abandoned mines and quarries BT: human impacts RT: industrial pollution SN: Mines and quarries that have been abandoned and may expose harmful chemicals to the environment. TNR: 1725 absorption USE: sorption abstracts USE: reports Ac USE: actinium accessing USGS data and products USE: USGS information services acid deposition BT: atmospheric deposition (chemical & particulate) RT: atmospheric sciences human impacts UF: acid precipitation acid rain acid snow acidic deposition SN: The process by which emissions, chiefly sulfur and nitrogen compounds, either react with the atmosphere when deposited on earth by precipitation of snow, rain, or fog with a pH of 5.5 or below, or settle out as acidic particles or gases. TNR: 6 acidic deposition USE: acid deposition acid precipitation USE: acid deposition acid rain USE: acid deposition acid snow USE: acid deposition acoustic doppler current profiler USE: acoustic doppler current profiling acoustic doppler current profiling BT: acoustic methods RT: stream-gage measurement UF: ADCP hydroacoustics acoustic doppler current profiler SN: Field monitoring of water currents using the doppler effect with acoustic instruments. TNR: 1726 acoustic methods BT: field inventory and monitoring NT: sonar methods acoustic doppler current profiling SN: Study methods based on techniques of transmitting and receiving sound waves as well as measuring the properties of sound, such as pitch, absorption, frequency, intensity, or velocity. TNR: 10 actinide series elements BT: rare earth elements RT: actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium TNR: 1384 actinium BT: chemical elements RT: actinide series elements UF: Ac SN: Rare earth (actinide series) element with symbol Ac and atomic number 89 TNR: 1385 ADCP USE: acoustic doppler current profiling administrative and political boundaries BT: culture and demographics RT: cadastral and legal land descriptions geography UF: borders geographic boundaries governmental units political boundaries SN: Lines drawn on maps or described in documents which encompass territory controlled by a government or organizational unit that may or may not align with geographic or cultural barriers. Use for datasets containing boundary representations for political/administrative units and related information. TNR: 12 adsorption USE: sorption Advanced Very High Resolution Radiometer (AVHRR) USE: AVHRR aerial photographs US+: aerial photography image collections aerial photography BT: photography RT: remote sensing UF: aerial photographs aerial photos air photos orthoimagery orthophotographs SN: The process of taking pictures with a camera mounted in an aircraft. Use for both the process of photography from the air and the images produced by the process. TNR: 15 aerial photos US+: aerial photography image collections aeromagnetic maps US+: maps and atlases aeromagnetic surveying aeromagnetic surveying BT: remote sensing RT: electromagnetic surveying geography UF: aeromagnetic maps magnetic surveying SN: Mapping of the earth's magnetic field with the use of airborne electronic magnetometers. TNR: 18 aeroradiometric surveying BT: remote sensing RT: geography UF: gamma-ray spectrometric surveying SN: Mapping of gamma radiation from the earth's surface with airborne scintillation meters or gamma-ray spectrometers. TNR: 19 Ag USE: silver age dating (fission-track) USE: fission-track dating age dating (radiometric) USE: radiometric dating age dating (tree ring) USE: tree ring analysis age estimation methods BT: laboratory methods NT: fission-track dating luminescence dating tephrochronology sclerochronology RT: radiometric dating tree ring analysis UF: dating methods SN: Methods used to determine the age of earth materials, typically by laboratory analysis of properties of those materials. TNR: 1680 agricultural water use BT: offstream water use NT: irrigation RT: hydraulic engineering hydrology UF: livestock water use rural water use SN: Water used for soil cultivation, crop production and livestock rearing. TNR: 23 agriculture BT: topics NT: aquaculture RT: soil chemistry UF: farming horticulture livestock husbandry SN: The science and business of soil cultivation to raise crops and of animal husbandry to raise domesticated animals. TNR: 24 airborne imaging USE: remote sensing airborne visible infrared imaging spectrometer USE: AVIRIS air photos US+: image collections aerial photography air pollution US+: contamination and pollution atmospheric composition air temperature BT: atmospheric properties RT: atmospheric sciences UF: temperature (air) TNR: 27 air transportation USE: transportation Al USE: aluminum algae BT: organisms NT: calcareous nannoplankton diatoms dinoflagellates RT: algal blooms bacteria phycology protists periphyton SN: Chlorophyll-bearing primarily aquatic nonvascular species that have no true roots, stems, or leaves; most algae are microscopic, but some species can be as large as vascular plants. TNR: 29 algal blooms BT: ecological processes RT: algae hazards phycology population dynamics UF: brown tides harmful algal blooms red tides SN: Exceptional growth of algae and cyanobacteria in lakes, rivers or oceans due to excessive nutrients or climatic conditions. TNR: 30 algology USE: phycology alien species USE: nonindigenous species alkali metal elements BT: chemical element groups RT: hydrogen lithium sodium potassium rubidium cesium francium TNR: 1388 alkaline earth elements BT: chemical element groups RT: beryllium magnesium calcium strontium barium radium TNR: 1389 alluvial sedimentation USE: sedimentation alluvial transport USE: sediment transport alluvium USE: unconsolidated deposits altimetry measurement BT: geolocation measurement RT: geography UF: satellite altimetry SN: The measurement of altitude, or height above mean sea level, using instruments such as aneroid barometers and radar altimeters. TNR: 36 aluminum BT: chemical elements RT: metal elements UF: Al SN: Metalloid element with symbol Al and atomic number 13 TNR: 1390 Am USE: americium americium BT: chemical elements RT: actinide series elements UF: Am SN: Rare earth (actinide series) element with symbol Am and atomic number 95 TNR: 1392 amphibians BT: vertebrates RT: herpetology SN: Vertebrates of the class Amphibia including frogs and toads (Anura), salamanders (Urodela), caecilians (Apoda) and extinct forms which are cold-blooded and have life stages in water as eggs and larval forms (tadpoles)until they metamorphose as adults. TNR: 37 anadromous fish US+: migratory species fish anatomy and physiology BT: life sciences NT: endocrinology histology immunology RT: plant and animal testing therapeutic methods UF: physiology SN: Study of the body structures (anatomy) and life functions and activities (physiology)of plants and animals. TNR: 39 animal and plant census BT: field inventory and monitoring UF: census SN: Inventory of macroscopic animals and plants by observation in the field. Used to estimate population and distribution. TNR: 1353 animal behavior BT: population and community ecology RT: ecology migration (organisms) migratory species SN: The way animals act or react to conditions in the environment and to other organisms, including life patterns such as migration, hibernation, and nocturnal living. TNR: 40 animal distribution USE: biogeography animals BT: organisms NT: invertebrates vertebrates RT: wildlife zoology UF: fauna SN: Multi-celled organisms of the kingdom Animalia with eukaryotic cells (cells with distinct nuclei containing genetic material and bounded by thin membranes) that are heterotrophic (obtaining energy from organic substances produced by other organisms). TNR: 45 animal tagging USE: plant and animal tagging animal testing USE: plant and animal testing animal tracking BT: field sampling RT: telemetry wildlife biology UF: tracking SN: Method of studying animals by following spoor (footprints, droppings, scent, and other evidence) in an area to document the presence and movements of the animal and its interactions within the landscape. TNR: 44 animations BT: product types SN: Graphical representation of scientific data presented as a timed sequence of visual images, normally without sound. TNR: 1740 annelids USE: segmented worms anoxia USE: oxygen content (water) anthracite resources USE: coal resources antimony BT: chemical elements RT: metal elements UF: Sb SN: Metalloid element with symbol Sb and atomic number 51 TNR: 1393 aquaculture BT: agriculture RT: commercial fishery resources fishery resources UF: fish farming SN: The farming of organisms that live in water, such as fish, shellfish, and algae for human use. TNR: 52 aquatic biology BT: life sciences RT: aquatic ecosystems benthic ecosystems commercial fishery resources ecology estuarine ecosystems fishery resources freshwater ecosystems inland fishery resources macroinvertebrates marine biology marine ecosystems marine fishery resources migratory species plankton recreational fishery resources shellfish water quality wetland ecosystems SN: The scientific study of organisms living in or near water. This term is to be used for the science of 'aquatic biology' and for biological studies in fresh and brackish water. For marine biological studies, use 'marine biology'. TNR: 53 aquatic ecosystems BT: ecosystems NT: benthic ecosystems estuarine ecosystems freshwater ecosystems marine ecosystems RT: aquatic biology coastal ecosystems ecology limnology marine biology UF: planktonic ecosystems SN: Communities of interdependent organisms living primarily in or on water. TNR: 54 aquatic vegetation BT: vegetation UF: hydrophytes mangroves seagrass seaweeds SN: Plants living primarily in or under water. TNR: 1705 aquifer-surface water interaction USE: ground-water and surface-water interaction aquifer level USE: ground-water level Ar USE: argon arachnids BT: arthropods RT: entomology invertebrate zoology UF: false scorpions mites spiders ticks SN: Carnivorous arthropods, chiefly terrestrial, of the class Arachnida including spiders, scorpions, mites, ticks, false scorpions, palpigrades, solifugids, and harvestmen. TNR: 55 arboreal ecosystems USE: forest ecosystems archaea BT: organisms RT: microbiology UF: archaebacteria SN: Microscopic organisms of the domain Archaea living on a diet of hydrogen and carbon dioxide, once thought to be bacteria, and often inhabiting extreme environments, such as thermal vents and hot springs, extremely alkaline and acidic waters, hypersaline water, and anoxic habitats. TNR: 56 archaean BT: precambrian UF: archean TNR: 1622 archaebacteria USE: archaea archaeology USE: archeology archean USE: archaean archeology BT: social sciences UF: archaeology SN: Study of human cultures through the recovery and analysis of their material relics. TNR: 1691 archives (USGS) USE: USGS libraries and archives argon BT: chemical elements RT: noble gas elements UF: Ar SN: Noble gas element with symbol Ar and atomic number 18 TNR: 1395 argon-argon dating USE: radiometric dating arsenic BT: chemical elements RT: nonmetal elements UF: As SN: Nonmetal element with symbol As and atomic number 33 TNR: 1396 arthropods BT: invertebrates NT: arachnids crustaceans horseshoe crabs insects trilobites RT: invertebrate zoology SN: Invertebrates belonging to the largest phylum of animals, Arthropoda, with an exoskeleton, segmented bodies, and jointed appendages, including many subphyla and classes, such as insects, crustaceans, horseshoe crabs, sea spiders, centipedes, millipedes, and the extinct trilobites. TNR: 58 articles (publications) USE: reports artificial recharge USE: water resource management As USE: arsenic Ask-A services (USGS) USE: USGS expertise services astatine BT: chemical elements RT: halogen elements UF: At SN: Halogen element with symbol At and atomic number 85 TNR: 1398 asteroid impact USE: impact cratering asthenosphere BT: mantle (earth) RT: tectonophysics SN: A layer of the earth within the upper mantle and directly below the lithosphere. This layer has a semi-solid consistency that reaches to about 200 kilometers (124 miles) below the surface. TNR: 61 astronomy USE: planetary sciences At USE: astatine atlases USE: maps and atlases atmosphere properties USE: atmospheric properties atmospheric and climatic processes BT: biological and physical processes NT: evaporation atmospheric circulation atmospheric deposition (chemical & particulate) climate change droughts ocean-atmosphere interaction precipitation (atmospheric) storms wind greenhouse effect RT: atmospheric properties atmospheric sciences meteorology snow and ice cover UF: climate weather monitoring weather observations weather microclimate SN: Phenomena affecting or occurring within the mass of gases that surrounds the earth, including its physics, chemistry, dynamics, and weather conditions. TNR: 63 atmospheric circulation BT: atmospheric and climatic processes RT: atmospheric sciences water circulation SN: Movement of atmospheric gases around the earth. TNR: 64 atmospheric composition BT: atmospheric properties NT: greenhouse gases ozone layer RT: atmospheric sciences UF: air pollution SN: Components of the mass of gases that surrounds a planet. The earth's atmosphere consists of nitrogen, oxygen, and small portions of other gases. TNR: 65 atmospheric deposition (chemical & particulate) BT: atmospheric and climatic processes NT: acid deposition RT: atmospheric sciences precipitation (atmospheric) sedimentation UF: atmospheric deposition (chemical and particulate) SN: The transfer of substances from the air to the surface of the earth, either in wet form (rain, fog, snow, dew, frost, hail) or in dry form (gases, aerosols, particles). TNR: 66 atmospheric deposition (chemical and particulate) USE: atmospheric deposition (chemical & particulate) atmospheric properties BT: earth characteristics NT: air temperature atmospheric composition RT: atmospheric and climatic processes atmospheric sciences UF: atmosphere properties SN: Characteristics of the mass of gases surrounding the earth such as composition, temperature, pressure, and humidity. TNR: 67 atmospheric sciences BT: earth sciences NT: climatology meteorology RT: acid deposition air temperature atmospheric and climatic processes atmospheric circulation atmospheric composition atmospheric deposition (chemical & particulate) atmospheric properties droughts fires global change global warming greenhouse gases ocean temperature ocean-atmosphere interaction ozone layer precipitation (atmospheric) SN: Studies relating to composition, structure, physics, chemistry, and dynamics of the atmosphere. TNR: 68 atomic absorption analysis BT: chemical analysis RT: biochemistry geochemistry SN: Technique used to identify chemicals based on the measurement of the spectra produced by atoms and molecules with absorption of electromagnetic radiation. TNR: 69 atomic emission spectroscopy BT: chemical analysis UF: ICP-AES inductively coupled plasma-atomic emission spectrometry SN: Chemical detection of element concentration by examining the intensity and wavelength of light emitted from the sample when gaseous sample is ionized and maintained in a plasma state. TNR: 1342 Au USE: gold audio recordings USE: sound recordings autumn BT: seasons UF: fall (season) TNR: 1624 avalanches USE: landslides AVHRR BT: infrared imaging RT: geography sea surface temperature UF: AVHRR images Advanced Very High Resolution Radiometer (AVHRR) SN: Advanced Very High Resolution Radiometer or broad-band, four or five channel scanner, sensing in the visible, near-infrared, and thermal infrared portions of the electromagnetic spectrum. This information is used to estimate characteristics of the land and sea surface such as temperature and overall health of vegetation. TNR: 74 AVHRR images US+: image collections AVHRR avian flu USE: avian influenza avian influenza BT: health and disease UF: avian flu bird flu HPAI H5N1 SN: A virulent disease of poultry and wild birds that has spread throughout a large geographic area in Asia and Eastern Europe since it was first documented in 1997 in Asia. TNR: 1732 aviation USE: transportation aviation safety BT: hazard preparedness RT: volcanic activity SN: Effects on air transportation of natural hazards such as volcanic activity (ash plumes and volcanic clouds). TNR: 1694 AVIRIS BT: infrared imaging UF: airborne visible infrared imaging spectrometer TNR: 1379 B USE: boron Ba USE: barium bacteria BT: organisms RT: algae microbiology SN: Single celled microorganisms, beneficial or pathogenic, without a nuclear membrane. TNR: 76 bacteriology BT: microbiology RT: culturing (specimens) health and disease SN: Study of the single celled microorganisms known as bacteria. TNR: 77 banding USE: plant and animal tagging bankfull stage USE: floods barium BT: chemical elements RT: alkaline earth elements UF: Ba SN: Alkaline earth element with symbol Ba and atomic number 56 TNR: 1403 baseline characterization USE: field inventory and monitoring basement maps US+: maps and atlases bedrock geologic units bathymetry BT: topography RT: geomorphology limnology ocean sciences sea-floor characteristics UF: bathymetry data sea floor topography underwater contours SN: The topography of a body of water, especially the ocean, determined by measurements of depth. TNR: 80 bathymetry data USE: bathymetry bathymetry measurement BT: geolocation measurement RT: geography sonar methods SN: Means of determining the depth to the floor of a body of water, especially the ocean. TNR: 82 bats BT: mammals SN: Small flying mammals of the order Chiroptera. TNR: 1747 Be USE: beryllium bears BT: mammals UF: polar bears grizzly bears black bears SN: Large wild mammals of the family Ursidae. Includes black and brown (grizzly) bears and polar bears. TNR: 1746 bed forms USE: bedforms bedforms BT: sedimentary rocks RT: sedimentology UF: bed forms SN: Fluctuations from horizontal layers in sediments or sedimentary rocks made by flow on the beds of alluvial channels. TNR: 83 bedload USE: sediment transport bed load USE: sediment transport bedrock geologic units BT: stratigraphic sections RT: stratigraphy UF: basement maps geologic formations SN: Units of consolidated (solid) rock that underlie soils or other unconsolidated materials. TNR: 84 bees USE: bees and wasps bees and wasps BT: insects UF: wasps bees TNR: 1737 benchmarks USE: field monitoring stations benthic ecosystems BT: aquatic ecosystems RT: aquatic biology ecology limnology marine biology SN: Biologic communities and habitats at the bottom of lakes, streams, or oceans. TNR: 85 benthos BT: organism groupings (non-taxonomic) SN: Animals that live on the bottom of water bodies. TNR: 1345 berkelium BT: chemical elements RT: actinide series elements UF: Bk SN: Rare earth (actinide series) element with symbol Bk and atomic number 97 TNR: 1405 beryllium BT: chemical elements RT: alkaline earth elements UF: Be SN: Alkaline earth element with symbol Be and atomic number 4 TNR: 1406 beryllium isotope analysis BT: light stable isotope analysis SN: Method of age determination based on measurement of the activity of beryllium-10, used in dating deep-sea sediments, and in determining sedimentation rates. TNR: 86 Bh USE: bohrium Bi USE: bismuth bibliographies BT: catalogs and indexes RT: reports SN: List of publications on a given topic, by an author or group, or published in a specific time period. Limited here to lists primarily of paper documents. TNR: 87 biking USE: recreation bioaccumulation BT: ecological processes RT: ecology ecotoxicology UF: bioconcentration SN: The biological sequestering of a substance at a higher concentration than that at which it occurs in the surrounding environment or medium. Also, the process whereby a substance enters an organism through the gills, epithelial tissues, dietary, or other sources. TNR: 88 biochemistry BT: life sciences RT: atomic absorption analysis biogeochemical cycling carbon cycling carbon isotope analysis chemical analysis chromatography DNA sequencing electrophoresis flow cytometry food web gas chromatography isotopic analysis light stable isotope analysis liquid chromatography mass spectroscopy mercury contamination neutron activation analysis nutrient cycling oxygen isotope analysis particle-beam spectroscopy pesticide and herbicide contamination polymerase chain reaction tritium analysis UF: biogeochemistry chemistry (life sciences) environmental chemistry SN: Study of chemical processes that occur within or are mediated by living organisms. TNR: 89 biocide contamination USE: pesticide and herbicide contamination bioconcentration USE: bioaccumulation biodegradation BT: geochemical processes UF: natural attenuation (harmful chemicals) SN: Reduction in the concentration of harmful chemicals by the action of animals and plants. TNR: 1346 biodiversity BT: population and community ecology NT: ecosystem diversity genetic diversity species diversity RT: biogeography ecological competition ecology endangered species endemic species invasive species life sciences native species nonindigenous species UF: biological diversity diversity (biological) SN: The variety in form, genetics, and ecological roles of organisms within a specific geographic area. TNR: 92 bioenergetic processes USE: biological and physical processes biogeochemical cycling BT: ecological processes NT: carbon cycling nutrient cycling RT: biochemistry decomposers ecology geochemistry geochemical processes UF: biogeochemical functioning biogeochemical processes decomposition (organic) organic decomposition SN: The cycling of chemical constituents through a biological system. TNR: 93 biogeochemical functioning USE: biogeochemical cycling biogeochemical processes USE: biogeochemical cycling biogeochemistry USE: biochemistry biogeography BT: population and community ecology RT: biodiversity ecology ecosystem monitoring migration (organisms) migratory species population dynamics wildlife population management UF: animal distribution distribution of animals distribution of plants distribution of species flyways plant distribution species distribution maps species distribution species geographic range SN: The study of the geographic distributions of plants and animals. TNR: 96 biographies USE: reports bioinformatics USE: biological informatics biological and physical processes BT: topics NT: atmospheric and climatic processes ecological processes fires geologic processes geochemical processes ocean processes physiological processes hydrologic processes evolution impact cratering UF: bioenergetic processes SN: All continuing activities, functions, and phenomena associated with organisms and non-living matter. TNR: 101 biological diversity USE: biodiversity biological informatics BT: information sciences RT: life sciences UF: bioinformatics SN: Development and use of computer, statistical, and other tools in the collection, organization, dissemination, and use of information to solve problems in the life sciences. TNR: 103 biological invasions US+: migration (organisms) invasive species biological oceanography USE: marine biology biological organisms USE: organisms biological population management BT: natural resource management NT: fishery management reintroduction (organisms) wildlife population management pest control RT: ecosystem monitoring population and community ecology UF: conservation genetics SN: Judicious means of controlling or directing numbers and life conditions of organisms living in a specific locality to achieve a selected goal. TNR: 107 biological productivity BT: ecological processes RT: ecology life sciences SN: The rate at which primary producers in the ecosystem utilize solar energy to produce food for consumption by other organisms. Do not use this term for "productivity" of organisms related to studies of the reproduction rates of a species. TNR: 108 biological remediation USE: bioremediation biological sciences USE: life sciences biology USE: life sciences bioluminescence BT: physiological processes SN: Emission of light by organisms. TNR: 1348 bionomics USE: ecology bioremediation BT: remediation RT: ecology ecosystem monitoring UF: biological remediation revegetation SN: Use of biological methods, usually involving microorganisms, to break down or neutralize contaminants in soil, water, and wastes. TNR: 113 biosphere USE: ecosystems biostratigraphy BT: geologic history RT: fossils ichnofossils paleontology stratigraphy SN: Branch of geology concerned with the separation and differentiation of rock units based on the fossils they contain. TNR: 115 biota BT: organism groupings (non-taxonomic) RT: life sciences SN: All living organisms in an area. TNR: 116 biotelemetry USE: telemetry bird banding USE: plant and animal tagging bird flu USE: avian influenza birds BT: vertebrates RT: ornithology UF: shorebirds water birds waterfowl SN: Land vertebrates belonging to the class Aves with warm blood, feathers, wings, and reproduction characterized by egg laying. TNR: 119 bird watching USE: recreation bismuth BT: chemical elements RT: metal elements UF: Bi SN: Metalloid element with symbol Bi and atomic number 83 TNR: 1409 bituminous coal resources USE: coal resources Bk USE: berkelium black bears USE: bears blizzards BT: storms SN: Severe snowstorms with intense winds. TNR: 121 boating USE: recreation bohrium BT: chemical elements RT: metal elements UF: Bh SN: Metal element with symbol Bh and atomic number 107 TNR: 1411 bolide impact USE: impact cratering bolides USE: meteorites books and book chapters USE: reports borders USE: administrative and political boundaries borehole logging BT: field inventory and monitoring NT: borehole temperature logging electrical resistivity logging gamma-ray logging RT: geophysics stratigraphy UF: well logging SN: Method of recording the physical characteristics of the subsurface as a function of depth by observations during drilling of a well or borehole, studying the resulting core, or by lowering instruments into a drilled hole. TNR: 125 borehole temperature logging BT: borehole logging RT: geophysics SN: Method of recording the measured temperature of the subsurface as a function of depth by lowering instruments into the hole. TNR: 126 boron BT: chemical elements RT: nonmetal elements UF: B SN: Nonmetal element with symbol B and atomic number 5 TNR: 1412 botany BT: life sciences NT: palynology phycology RT: drilling and coring ferns and fern allies flowering plants forest resources gymnosperms liverworts and hornworts mosses mycology nonvascular plants paleobotany plants (organisms) producers (organisms) vascular plants vegetation SN: The science of plants. TNR: 127 bouguer anomaly BT: gravitational field (earth) TNR: 1675 Br USE: bromine brachiopods USE: bryozoans and brachiopods bridge scour USE: scour bromine BT: chemical elements RT: halogen elements UF: Br SN: Halogen element with symbol Br and atomic number 35 TNR: 1414 brown tides USE: algal blooms bryozoans and brachiopods BT: invertebrates RT: invertebrate paleontology invertebrate zoology UF: brachiopods ectoprocta SN: Aquatic invertebrates, usually marine, belonging to the phyla Bryozoa and Brachiopoda. Brachiopods, or clam shells, are solitary living invertebrates characterized by two shells and a lophophore, which is a complex food gathering organ. Bryozoans are colonial and include moss coral and moss polyps. TNR: 130 budget (USGS) USE: USGS budget bugs USE: insects building stone resources BT: nonmetallic mineral resources RT: economic geology rocks and deposits sedimentology UF: crushed stone dimension stone SN: Deposits of rocks used in construction, including crushed stone and dimension stone. Dimension stone includes limestone and granite, quarried in large blocks, and shaped in cubes, panels and other forms. TNR: 132 business and economics BT: culture and demographics RT: social sciences UF: commerce economics SN: The activities and processes associated with the production, distribution, and consumption of goods and services. TNR: 133 business partners (USGS) USE: USGS partnerships butterflies and moths BT: insects RT: entomology UF: lepidoptera moths SN: Insects of the order Lepidoptera that have four wings with overlapping, often highly colored scales. They undergo four life cycle stages: eggs, caterpillar larvae, pupae, and the winged adults. TNR: 135 C USE: carbon Ca USE: calcium cadastral and legal land descriptions BT: culture and demographics RT: administrative and political boundaries geography social sciences UF: land partitioning systems legal land descriptions cadastral maps SN: Records in official registers showing extent, boundaries, and ownerships of land for administration and taxation. TNR: 136 cadastral maps US+: cadastral and legal land descriptions maps and atlases cadmium BT: chemical elements RT: metal elements UF: Cd SN: Metal element with symbol Cd and atomic number 48 TNR: 1417 caenozoic USE: cenozoic calcareous nannoplankton BT: algae RT: micropaleontology phycology plankton phytoplankton UF: coccoliths SN: Organisms of the kingdom Protista that normally produce coccoliths, microscopic structures of calcite (calcium carbonate), during some phase of their life cycle. TNR: 138 calcium BT: chemical elements RT: alkaline earth elements UF: Ca SN: Alkaline earth element with symbol Ca and atomic number 20 TNR: 1418 californium BT: chemical elements RT: actinide series elements UF: Cf SN: Rare earth (actinide series) element with symbol Cf and atomic number 98 TNR: 1419 cambrian BT: paleozoic TNR: 1626 camera calibration BT: laboratory methods SN: Optical calibration of cameras that are typically used in airborne remote sensing. TNR: 1670 camera tows USE: underwater photography camping USE: recreation canoeing USE: recreation capturing (animals) BT: field sampling RT: specimen collecting zoology UF: trapping (animals) SN: Collecting individual animals in the field by various methods in order to obtain information about the species or population and its ecology. Capturing methods are adapted to the habits and habitats of the target species and include both live trapping and kill trapping methods. TNR: 140 carbon BT: chemical elements RT: nonmetal elements UF: C SN: Nonmetal element with symbol C and atomic number 6 TNR: 1420 carbon-14 analysis BT: radiometric dating RT: carbon isotope analysis geochronology UF: carbon dating radiocarbon dating SN: Method to determine the age of organic geologic and archaeological specimens, aged approximately 3,000 to 50,000 years, by determining the decay of the radioactive isotope carbon-14. TNR: 143 carbon cycling BT: biogeochemical cycling RT: biochemistry ecology geochemistry SN: The circulation of carbon in the biosphere, atmosphere, and hydrosphere through a series of processes that include photosynthesis, consumption, and respiration. TNR: 141 carbon dating USE: carbon-14 analysis carbon isotope analysis BT: light stable isotope analysis RT: biochemistry carbon-14 analysis geochemistry SN: Experimental determination of the proportion of a given stable carbon isotope (C12 or C13) in a sample. TNR: 142 carbon sequestration BT: geochemical processes SN: Long-term storage of carbon in soils and terrestrial organic material, typically of importance in understanding the balance of CO2 in the global climate system. TNR: 1731 careers in science USE: scientific careers carnivores BT: consumers (organisms) RT: ecology zoology UF: predators SN: Flesh-eating animals. TNR: 145 cartographic data (digital) USE: geospatial datasets cartography BT: geography RT: map coordinate systems maps and atlases UF: digital cartography map making mapmaking mapping SN: The science and art of making maps. TNR: 147 catalogs and indexes BT: product types NT: bibliographies directories gazetteers RT: reports USGS clearinghouses UF: indexes lists of publications metadata SN: Detailed enumeration of related items listed in a given order, or alphabetical lists of topics used for information retrieval. TNR: 148 catastrophes USE: hazards Categories NT: methods product types sciences topics USGS time periods SN: Thematic terms for categorizing information resources. This thesaurus is intended to support finding and understanding scientific information. TNR: 1 caving USE: recreation Cd USE: cadmium Ce USE: cerium cell biology BT: life sciences RT: flow cytometry molecular biology UF: cellular biology cytology SN: Branch of biology that deals with the study of the formation, structure, and physiology of cells. TNR: 151 cellular biology USE: cell biology cenozoic BT: phanerozoic NT: quaternary tertiary UF: caenozoic TNR: 1627 census USE: animal and plant census cerium BT: chemical elements RT: lanthanide series elements UF: Ce SN: Rare earth (lanthanide series) element with symbol Ce and atomic number 58 TNR: 1423 cesium BT: chemical elements RT: alkali metal elements UF: Cs SN: Alkali metal element with symbol Cs and atomic number 55 TNR: 1424 Cf USE: californium charts USE: maps and atlases checklists BT: reports SN: Inventories or lists of related items for checking off or reference. TNR: 152 chemical analysis BT: laboratory methods NT: atomic absorption analysis chromatography DNA sequencing electrophoresis flow cytometry mass spectroscopy neutron activation analysis particle-beam spectroscopy polymerase chain reaction x-ray diffraction atomic emission spectroscopy RT: biochemistry geochemistry UF: detection (chemical) geochemical surveys leaching (analytical method) mineralogical analysis nuclear magnetic resonance spectroscopy sediment geochemistry SN: Chemical techniques used to identify the composition of substances. TNR: 153 chemical element groups BT: elements NT: metal elements halogen elements alkali metal elements alkaline earth elements noble gas elements nonmetal elements rare earth elements SN: Groups shown at TNR: 1426 chemical elements BT: elements NT: astatine cerium dubnium iron hydrogen californium fluorine francium europium lawrencium arsenic antimony iodine berkelium fermium germanium neon lithium lutetium magnesium neodymium molybdenum chlorine hassium cesium copper carbon bohrium boron bromine indium helium gadolinium gallium meitnerium mercury cadmium gold actinium erbium bismuth lead chromium einsteinium lanthanum manganese cobalt barium aluminum americium krypton darmstadtium beryllium argon calcium holmium mendelevium dysprosium hafnium curium irridium neptunium nickel niobium nitrogen nobelium osmium oxygen palladium phosphorus platinum plutonium polonium potassium praseodymium prometium protactinium radium radon rhenium rhodium rubidium ruthenium rutherfordium samarium scandium seaborgium selenium silicon silver sodium strontium sulfur tantalum technetium tellurium terbium thallium thorium thulium tin titanium tungsten ununnilium ununnubium ununnunium uranium vanadium xenon ytterbium yttrium zinc zirconium SN: Chemical substances distinguished by atomic number. http://periodic.lanl.gov/ TNR: 1427 chemical oceanography USE: marine chemistry chemistry (Earth sciences) USE: geochemistry chemistry (life sciences) USE: biochemistry chloride concentration USE: salinity chlorine BT: chemical elements RT: halogen elements UF: Cl SN: Halogen element with symbol Cl and atomic number 17 TNR: 1428 chondrites USE: meteorites chromatography BT: chemical analysis NT: gas chromatography liquid chromatography RT: biochemistry geochemistry SN: Analytical techniques used to separate or partition the components of a gaseous or liquid mixture by differences in absorption rates during flow around or over surface absorbents such as columns of silica, filter papers, or gels. TNR: 158 chromium BT: chemical elements RT: metal elements UF: Cr SN: Metal element with symbol Cr and atomic number 24 TNR: 1429 chronostratigraphy USE: geologic history circulation (ocean) USE: ocean circulation circulation (water) USE: water circulation Cl USE: chlorine clay deposits BT: unconsolidated deposits RT: economic geology nonmetallic mineral resources sedimentology SN: Fine-grained sedimentary soil deposits, containing hydrated silicas of aluminum, that are plastic and sticky when wet and harden when heated. TNR: 164 clearinghouses (USGS) USE: USGS clearinghouses cleavage (rock) USE: fracture (geologic) climate USE: atmospheric and climatic processes climate change BT: atmospheric and climatic processes NT: desertification RT: climatology global change global warming greenhouse gases UF: climatic change global climate change climate variability paleoclimate climate history SN: Long-term alteration in the characteristic weather conditions of a region, such as changes in precipitation and temperature. TNR: 168 climate history USE: climate change climate variability USE: climate change climatic change USE: climate change climatology BT: atmospheric sciences RT: climate change desertification meteorology ocean circulation sea-level change SN: Scientific study of the characteristic weather conditions of geographic areas. TNR: 170 climbing USE: recreation clines USE: ecosystems Cm USE: curium Co USE: cobalt coal bed methane resources USE: coalbed methane resources coalbed methane resources BT: natural gas resources RT: coal resources economic geology UF: coal bed methane resources methane resources (coalbed) SN: Resources of methane-rich gas generated and stored in coalbeds. TNR: 173 coal resources BT: energy resources RT: coalbed methane resources economic geology UF: anthracite resources bituminous coal resources lignite resources subbituminous coal resources SN: Fuel resources such as anthracite, lignite, bituminous coal, or coke, consisting largely of carbonaceous material and formed from fossilized plants. TNR: 172 coastal ecosystems BT: terrestrial ecosystems RT: aquatic ecosystems ecology UF: littoral ecosystems SN: Biological communities and habitats within the narrow zones of land between the margin of oceans or seas and large landmasses. TNR: 174 coastal fisheries USE: marine fishery resources coastal fishing USE: marine fishery resources cobalt BT: chemical elements RT: metal elements UF: Co SN: Metal element with symbol Co and atomic number 27 TNR: 1433 coccoliths USE: calcareous nannoplankton coelenterates BT: invertebrates RT: invertebrate zoology reef ecosystems UF: corals jellyfish sea anemones SN: Freshwater and marine invertebrates, such as corals, jellyfish, and sea anemones, belonging to the phylum Coelenterata and living as sedentary polyps or free swimming medusae. TNR: 177 collection of specimens USE: specimen collecting college programs (USGS) USE: USGS college programs colloquia (USGS) USE: USGS colloquia colonization (organisms) USE: dispersal (organisms) columbium USE: niobium comet impact USE: impact cratering commensalism USE: symbiosis commerce USE: business and economics commercial fishery resources BT: fishery resources RT: aquaculture aquatic biology ichthyology marine biology marine fishery resources SN: Stocks of fish and other seafood used for marketing purposes. TNR: 185 commercial water use BT: offstream water use RT: hydraulic engineering hydrology SN: Use of water for motels, hotels, restaurants, office buildings, and other commercial facilities and institutions. TNR: 186 community ecology BT: population and community ecology RT: ecological competition ecology SN: Study of the relationships of species that interact in a common area. TNR: 187 community education (USGS) USE: USGS lifelong learning programs compaction BT: earth material properties UF: soil compaction SN: Overall density of an unconsolidated earth material. TNR: 1714 composite burn index US+: remote sensing fire damage computational methods BT: methods NT: image analysis mathematical modeling relative abundance analysis spatial analysis statistical analysis topological analysis visualization methods UF: mathematical methods SN: Mathematical techniques used to analyze numerical data. TNR: 189 computer program USE: scientific software computer science BT: information sciences SN: Study of computers, including their design (architecture), uses (computations, data processing), and systems control. TNR: 190 conflict resolution methods USE: decision support methods coniferous forests ecosystems USE: forest ecosystems conodonts BT: invertebrates RT: invertebrate paleontology micropaleontology SN: Microscopic teeth of primitive, boneless, eel-like animals, similar to modern hagfish, that lived in many of the world's oceans from the Cambrian through Triassic Periods of geologic time (550 to 210 million years ago). TNR: 192 conservation USE: natural resource management conservation genetics US+: genetic diversity biological population management consumers (organisms) BT: organism groupings (non-taxonomic) NT: carnivores herbivores omnivores RT: ecology zoology SN: Organisms unable to produce food from nonliving matter and dependent on ingesting other animals, plants, or particulate organic matter. TNR: 194 consumptive use (water) USE: water use contacts (geologic) USE: geologic contacts contaminant transport BT: ecological processes RT: ecotoxicology SN: Processes involved in the movement of impurities through air, water, and soil. TNR: 196 contamination and pollution BT: topics NT: nonpoint-source pollution industrial pollution pesticide and herbicide contamination toxic radionuclide contamination toxic trace element contamination pharmaceutical contamination RT: human impacts waste treatment and disposal ecotoxicology hazards water quality UF: water pollution soil pollution natural contaminants pollution air pollution effluent outfall SN: Introduction of harmful substances into the environment by human action or natural processes. TNR: 769 continental drift USE: tectonic processes continental lithosphere BT: lithosphere RT: tectonophysics UF: craton SN: The earth's hard, outermost shell comprised of the crust and the upper part of the mantle. TNR: 199 continuing education (USGS) USE: USGS lifelong learning programs contour lines USE: topography contracts (USGS) USE: USGS contracts and grants controlled burns USE: controlled fires controlled fires BT: fire control RT: fires fire control UF: controlled burns fires (controlled) managed fires SN: Prescribed burns used to burn trees, brush, and undergrowth that would fuel a large wildfire. Do not confuse this term with 'fire control'. It is one of the tools used in fire control. TNR: 202 controlled flooding BT: natural resource management RT: floods UF: flooding (controlled) managed flooding SN: The deliberate inundation of land or wetland, or an increase in river flow below dams for restoration or research purposes. Do not confuse with flood control. TNR: 203 controlled vocabularies USE: terminologies and classifications cooperative research & development agreements (CRADAs) USE: USGS cooperative research & development agreements (CRADAs) cooperative research (USGS) USE: USGS partnerships cooperative research and development agreements USE: USGS cooperative research & development agreements (CRADAs) cooperators (USGS) USE: USGS partnerships coordinate systems USE: map coordinate systems copper BT: chemical elements RT: metal elements UF: Cu SN: Metal element with symbol Cu and atomic number 29 TNR: 1434 coral reef ecosystems USE: reef ecosystems corals USE: coelenterates core (earth) BT: earth structure NT: inner core (earth) outer core (earth) RT: geophysics SN: The superdense center of the earth composed of two layers: a liquid outer layer and a solid inner core of metallic iron-nickel alloy. TNR: 211 core analysis BT: laboratory methods RT: drilling and coring SN: Study of the composition and layers of cylindrical samples of rocks, trees, ice, and other materials extracted by drilling into a mass. Intended for broad use for the analysis of all types of core samples. The combination of this term with other terms will convey the context of the activity. TNR: 212 core sampling USE: drilling and coring coring USE: drilling and coring correlation USE: regression analysis Cr USE: chromium CRADAs USE: USGS cooperative research & development agreements (CRADAs) craton USE: continental lithosphere creep USE: mass wasting crenulation (geologic) USE: folding (geologic) cretaceous BT: mesozoic TNR: 1628 crushed stone USE: building stone resources crust (earth) BT: earth structure NT: lithosphere RT: tectonophysics SN: The outermost layer of the earth which is relatively thin, of lower density than the core, and rocky. TNR: 219 crustaceans BT: arthropods NT: ostracodes RT: invertebrate zoology shellfish SN: Arthropods of class Crustacea, such as crabs, lobsters, shrimp, prawns, or barnacles, with hard shells (exoskeleton) and segmented bodies with pairs of jointed appendages. TNR: 220 cryology USE: glaciology cryosphere USE: snow and ice cover cryptozoic USE: precambrian crystallography USE: mineralogy crystals USE: rocks and deposits Cs USE: cesium CTD measurement BT: field inventory and monitoring RT: limnology marine chemistry ocean sciences SN: Instrumental determination of conductivity, temperature, and pressure as a function of depth to determine the salinity of seawater. TNR: 222 Cu USE: copper culture and demographics BT: topics NT: administrative and political boundaries business and economics cadastral and legal land descriptions laws and regulations transportation geographic names RT: geography social sciences UF: demographics socioeconomics SN: Information on human behavior, ways of living and thinking, and characteristics of human populations. TNR: 223 culturing (specimens) BT: laboratory methods RT: bacteriology microbiology SN: Growing microorganisms, tissue cells, or other living matter in a specially prepared nutrient medium for diagnostic or scientific use. TNR: 224 Curie temperature analysis BT: paleomagnetic analysis RT: geophysics UF: temperature analysis (Curie) SN: Analysis of rock specimens using the Curie temperature point above which ferromagnetic materials lose permanent magnetism. TNR: 225 curium BT: chemical elements RT: actinide series elements UF: Cm SN: Rare earth (actinide series) element with symbol Cm and atomic number 96 TNR: 1438 customer support (USGS) USE: USGS customer support and user feedback cytology USE: cell biology darmstadtium BT: chemical elements RT: metal elements UF: Ds SN: Metal element with symbol Ds and atomic number 110 TNR: 1439 data USE: datasets data archives (USGS) USE: USGS libraries and archives databases USE: datasets data downloading (USGS) USE: USGS data downloading data management USE: information management methods datasets BT: product types NT: geospatial datasets hydrographic datasets time series datasets RT: USGS libraries and archives UF: data databases streamflow data water-quality data SN: Digital information in a format suitable for direct input to software that can analyze its meaning in the scientific, engineering, or business context for which the data were collected. TNR: 235 dating methods USE: age estimation methods Db USE: dubnium debris avalanches USE: landslides debris flows USE: landslides deciduous forest ecosystems USE: forest ecosystems decision support methods BT: management methods RT: geographic information systems (GIS) UF: conflict resolution methods SN: Mathematical, analytical, and social procedures used to aid groups and individuals in the process of making decisions. Includes protocols for discussion and mechanisms for facilitating communication among disparate groups as well as mechanical and technological aids to analysis and understanding. TNR: 237 decomposers BT: organism groupings (non-taxonomic) RT: biogeochemical cycling ecology life sciences SN: Organisms, chiefly microorganisms and invertebrates, that feed on dead plant or animal matter breaking it down and recycling the resulting elements and compounds in the environment. TNR: 238 decomposition (organic) USE: biogeochemical cycling deep sea fisheries USE: marine fishery resources deep sea fishing USE: marine fishery resources deforestation BT: human impacts SN: Reduction in the density of forest cover or tree canopy, typically by harvesting trees for human use or clearing land for other purposes such as agriculture. TNR: 1354 deformation (geologic) BT: geologic processes NT: folding (geologic) fracture (geologic) RT: geologic structure UF: rheology strain history SN: Change in form and structure of geologic materials in response to stress, typically heat and pressure. TNR: 1699 degradation products (chemical) USE: pesticide and herbicide contamination demographics USE: culture and demographics dendroecology US+: ecosystem monitoring vegetation density flow USE: sediment transport deposition (sediment) USE: sedimentation depth-to maps US+: structure contours maps and atlases desert ecosystems BT: terrestrial ecosystems RT: desertification ecology SN: Biological communities and habitats in arid areas with little precipitation, sparse, highly adapted vegetation, and extreme temperatures. TNR: 245 desertification BT: climate change RT: climatology desert ecosystems ecology hazards land use change SN: The alteration of arable land to dry, barren land due to prolonged drought or the deleterious effects of human intervention including overgrazing, overpopulation, or destructive agricultural practices. TNR: 246 detection (chemical) USE: chemical analysis developmental biology BT: life sciences RT: organism growth and development UF: embryology SN: Scientific study of the processes related to the transformation of living organisms from single cells to complex multi-celled individuals. TNR: 247 devonian BT: paleozoic TNR: 1630 diadromous fish US+: migratory species fish diagenesis BT: geologic processes RT: petrology sedimentology SN: Chemical, physical, and biological changes in sediment during and after its conversion to rock (lithification). TNR: 248 diatoms BT: algae RT: micropaleontology phycology SN: Microscopic, single-celled plants of the class Bacillariophyceae that have siliceous shells called frustules, and which grow in both marine and fresh water. TNR: 250 digital cartographic data USE: geospatial datasets digital cartographic datasets USE: geospatial datasets digital cartography USE: cartography digital line graphs USE: geospatial datasets dimension stone USE: building stone resources dinoflagellates BT: algae RT: micropaleontology phycology SN: Single-celled planktonic organisms, chiefly marine, characterized by twirling motion and whip-like flagella with affinities to both plants and animals. TNR: 261 dinosaurs BT: reptiles RT: vertebrate paleontology SN: Extinct reptiles, often gigantic, chiefly terrestrial, carnivorous or herbivorous, that lived during the Mesozoic era. TNR: 262 directories BT: catalogs and indexes RT: reports SN: Searchable lists of people, typically USGS staff. TNR: 263 disasters USE: hazards disease USE: health and disease disease (human) USE: environmental health (human) disease vectors BT: health and disease RT: life sciences SN: Organisms, such as insects, that transmit pathogens from one host to another. TNR: 267 dispersal (organisms) BT: ecological processes RT: ecology life sciences migration (organisms) UF: colonization (organisms) SN: The dissemination or geographic spread of individuals of a plant or animal population. TNR: 268 dissertations USE: reports dissolution USE: erosion dissolved constituents USE: water quality dissolved contaminants USE: water quality dissolved gases BT: water properties SN: Gases such as ammonia, oxygen, nitrogen, and carbon dioxide in solution measured in a water sample. TNR: 1682 dissolved oxygen USE: oxygen content (water) distribution of animals USE: biogeography distribution of plants USE: biogeography distribution of species USE: biogeography distribution services (USGS) USE: USGS sales and distribution services diversity (biological) USE: biodiversity DLG USE: geospatial datasets DNA sequencing BT: chemical analysis RT: biochemistry genetics UF: gene sequencing genome SN: Biochemical procedure to determine the order of nucleotides in genes. TNR: 276 documents USE: reports domestic water use BT: offstream water use NT: drinking water use RT: hydraulic engineering hydrology UF: public water supply residential water use SN: Use of water for household purposes, such as drinking, food preparation, bathing, washing clothes and dishes, flushing toilets, and watering lawns and gardens. TNR: 278 doppler radar imaging BT: radar imaging UF: radar ecology SN: Exploitation of the doppler effect in radar imaging to determine speed of airborne objects such as birds, butterflies, and clouds. TNR: 1727 dowsing USE: natural resource exploration drawdown USE: water use dredging BT: human impacts RT: hydraulic engineering SN: Removal of sediments from water bodies to aid navigation. TNR: 1671 drilling and coring BT: field sampling RT: botany core analysis geology glaciology well drilling UF: core sampling coring ice core sampling SN: Cutting into the subsurface, for example into underground strata, ice, or a tree trunk, to remove material for examination. Intended for broad use wherever coring is done. The combination of this term with other terms will convey the context of the activity. TNR: 281 drinking water USE: drinking water use drinking water use BT: domestic water use RT: water quality UF: drinking water potable water TNR: 283 droughts BT: atmospheric and climatic processes RT: atmospheric sciences hazards SN: Extended periods of moisture deficit over a sizeable area sufficient to have an adverse effect on vegetation, animals, or man. TNR: 284 Ds USE: darmstadtium dubnium BT: chemical elements RT: metal elements UF: Db SN: Metal element with symbol Db and atomic number 105 TNR: 1442 dust deposition USE: sedimentation dust storms BT: storms SN: Atmospheric disturbances in which a significant amount of dust is transported. TNR: 1696 dust transport USE: sediment transport Dy USE: dysprosium dynamic geology USE: tectonic processes dysprosium BT: chemical elements RT: lanthanide series elements UF: Dy SN: Rare earth (lanthanide series) element with symbol Dy and atomic number 66 TNR: 1444 early warning systems USE: hazard preparedness earth characteristics BT: topics NT: atmospheric properties earth structure geologic history geologic structure gravitational field (earth) land surface characteristics magnetic field (earth) ocean characteristics rocks and deposits snow and ice cover stratigraphic sections topography earth material properties RT: earth sciences SN: The measurable, definable properties and features of the earth. TNR: 287 earth history BT: geologic history RT: geochemistry geology tectonophysics SN: The structural and compositional changes that the earth has undergone from its formation. Use for discussions of the whole earth (or large sections of it) instead of regional studies. TNR: 288 earth material properties BT: earth characteristics NT: permeability porosity radioactivity resistivity compaction magnetism SN: Physical characteristics of rocks and unconsolidated earth materials such as soils and sediments. TNR: 1367 earthquake activity maps US+: maps and atlases earthquake occurrences earthquake epicenter maps US+: earthquake occurrences maps and atlases earthquake forecasting USE: earthquake probabilities earthquake hazards US+: hazards earthquakes earthquake monitoring USE: seismic networking earthquake occurrence maps US+: maps and atlases earthquake occurrences earthquake occurrences BT: earthquakes RT: seismology UF: earthquake occurrence maps earthquake seismology seismic activity earthquake activity maps earthquake epicenter maps ground motion maps seismic hazard maps shaking maps (seismic) seismicity strong motion ground motion SN: Time, location, severity, and mechanism of earthquake events, including the frequency and history of events in a given area. TNR: 299 earthquake prediction USE: earthquake probabilities earthquake preparedness BT: hazard preparedness SN: Awareness of the consequences of earthquake events and actions to be taken before, during, or after events. TNR: 301 earthquake probabilities BT: risk assessment RT: earthquakes neotectonic processes UF: earthquake forecasting earthquake prediction seismicity maps SN: That aspect of seismology that deals with the physical conditions or indications that precede an earthquake, in order to predict its probability, size, time, and location. TNR: 302 earthquakes BT: geologic processes NT: earthquake occurrences RT: earthquake probabilities hazards seismology tectonic processes tectonophysics volcanic activity UF: earthquake hazards SN: Ground shaking caused by the sudden release of accumulated strain by an abrupt shift of rock along a fracture in the earth or by volcanic or magmatic activity, or other sudden stress changes in the earth. TNR: 304 earthquake seismology US+: seismology earthquake occurrences Earth Science Information Centers (ESICs) USE: USGS Earth Science Information Centers (ESICs) earth sciences BT: sciences NT: atmospheric sciences geochemistry geography geology geophysics glaciology hydrology limnology ocean sciences paleontology soil sciences RT: earth characteristics natural resources scientific careers UF: geosciences SN: Broad term for all science related to the study of the earth. TNR: 291 earth structure BT: earth characteristics NT: core (earth) crust (earth) mantle (earth) RT: geologic structure structural geology tectonic processes tectonophysics SN: Major interior structural features of the planet earth. TNR: 292 earth tides BT: geologic processes SN: Periodic changes in the earth surface topography caused by the gravitational attraction of the moon and sun, measured with tiltmeters. Used in studies of volcanic activity. TNR: 1683 echinoderms BT: invertebrates RT: invertebrate zoology SN: Marine invertebrates of the phylum Echinodermata with a radial body and a calcareous exoskeleton. Includes starfishes, brittle stars, sea lilies, sea urchins, and sea cucumbers. TNR: 305 echo sounding USE: sonar methods ecoclines USE: ecosystems ecological competition BT: ecological processes RT: biodiversity community ecology ecology endangered species SN: The struggle between members of two or more species for scarce environmental resources. TNR: 308 ecological models USE: ecological processes ecological processes BT: biological and physical processes NT: transpiration algal blooms bioaccumulation biogeochemical cycling biological productivity contaminant transport dispersal (organisms) ecological competition ecosystem functions eutrophication extinction and extirpation habitat alteration migration (organisms) pollination succession (biological) RT: ecology population and community ecology soil formation UF: ecological models environmental processes SN: Dynamic biogeochemical interactions that occur among and between biotic and abiotic components of the biosphere. TNR: 310 ecologic succession USE: succession (biological) ecology BT: life sciences RT: animal behavior aquatic biology aquatic ecosystems benthic ecosystems bioaccumulation biodiversity biogeochemical cycling biogeography biological productivity bioremediation carbon cycling carnivores coastal ecosystems community ecology consumers (organisms) decomposers desert ecosystems desertification dispersal (organisms) ecological competition ecological processes ecosystem functions ecosystem monitoring ecosystems ecotoxicology endangered species endemic species estuarine ecosystems eutrophication extinction and extirpation fires food web forest ecosystems forest resources freshwater ecosystems global change global warming grassland ecosystems habitat alteration herbivores human impacts invasive species land use change long-term ecological monitoring marine ecosystems mercury contamination migration (organisms) migratory species native species nonindigenous species nutrient cycling omnivores pesticide and herbicide contamination plot sampling pollinators population and community ecology population dynamics producers (organisms) reef ecosystems remediation shrubland ecosystems succession (biological) terrestrial ecosystems tundra ecosystems vegetation waste treatment and disposal wetland ecosystems wetland functions UF: bionomics SN: Study of the relations between living plants and animals and their environment. TNR: 311 economic geology BT: geology RT: building stone resources clay deposits coal resources coalbed methane resources gas hydrate resources gem resources gold ores gravel deposits metallic ores mineral resources natural gas resources nonmetallic mineral resources energy resources oil resources oil sand resources oil shale resources sand deposits soil resources SN: Scientific study of the formation, location, and use of marketable geologic materials including fuels, metals, minerals, and water. TNR: 312 economics USE: business and economics ecosystem diversity BT: biodiversity SN: Measure of the variety of biological communities and habitats important for ecological stability. TNR: 314 ecosystem functions BT: ecological processes NT: wetland functions RT: ecology UF: ecosystem services estuarine ecosystem functions SN: The total life activities of organisms in habitats and the effects of those activities on the nonliving components of the environment. TNR: 315 ecosystem management BT: natural resource management RT: ecosystem monitoring UF: reintroduction (organisms) ecosystem preservation SN: Means of controlling or directing human practices, species populations, and physical environment within an ecosystem to achieve a selected state of sustainability. TNR: 316 ecosystem monitoring BT: field inventory and monitoring NT: long-term ecological monitoring RT: biogeography biological population management bioremediation ecology ecosystem management natural resource management population and community ecology relative abundance analysis remediation UF: indicator species observation dendroecology SN: Recording, evaluating, and actively intervening over time in the interaction of living and nonliving elements in a specific environment. TNR: 317 ecosystem preservation USE: ecosystem management ecosystems BT: population and community ecology NT: aquatic ecosystems terrestrial ecosystems wetland ecosystems RT: ecology habitats UF: biosphere clines ecoclines ecotones SN: The interacting populations of plants, animals, and microorganisms occupying a certain area, and their relationship to the environment. TNR: 319 ecosystem services USE: ecosystem functions ecotones USE: ecosystems ecotoxicology BT: life sciences RT: bioaccumulation contaminant transport ecology hazards human impacts mercury contamination contamination and pollution pesticide and herbicide contamination plant and animal testing therapeutic methods toxic radionuclide contamination toxic trace element contamination UF: environmental toxicology toxicology SN: Scientific study of causes, dispersal, and effects of contaminants on the environment. TNR: 320 ectoprocta USE: bryozoans and brachiopods Ediacaran BT: Neoproterozoic UF: Vendian SN: The last geological period of the Neoproterozoic Era, just before the Cambrian Period of the Paleozoic Era. TNR: 1735 educational services (USGS) USE: USGS educational services effluent USE: contamination and pollution einsteinium BT: chemical elements RT: actinide series elements UF: Es SN: Rare earth (actinide series) element with symbol Es and atomic number 99 TNR: 1445 electrical resistivity logging BT: borehole logging RT: electromagnetic surveying stratigraphy UF: resistivity sounding SN: Recordings made to identify the composition of subterranean materials at different depths in a borehole by measuring their ability to resist the flow of an electric current. TNR: 325 electromagnetic surveying BT: field inventory and monitoring RT: aeromagnetic surveying electrical resistivity logging UF: magnetic surveying magnetotelluric sounding SN: Method of determining the shape and constituency of near-surface earth structures by variations of responses of the materials to electrical and magnetic fields. Use for ground-based methods of imaging. TNR: 326 electron microscopy BT: microscopy NT: scanning electron microscopy SN: Study of small particles of matter with a microscope that produces a magnified image by using a beam of electrons focused by magnetic lenses. TNR: 327 electrophoresis BT: chemical analysis RT: biochemistry SN: Analytical technique to separate and identify components in a mixture using the differential migration of molecules based on their net charge through a paper or gel medium. TNR: 328 elements BT: topics NT: chemical elements chemical element groups SN: Chemical elements and element groups TNR: 1382 elevation USE: topography El Nino USE: ocean-atmosphere interaction embryology USE: developmental biology emergency management resources USE: hazards emergency response planning USE: hazard preparedness employment opportunities (USGS) USE: USGS employment and volunteer opportunities endangered species BT: organism groupings (non-taxonomic) RT: biodiversity ecological competition ecology life sciences SN: Plant or animal species reduced to such low numbers of individuals that they are at risk of becoming extinct. TNR: 332 endemic species BT: native species RT: biodiversity ecology life sciences SN: Plant and animals species native to and confined to specific geographic areas. TNR: 333 endocrinology BT: anatomy and physiology RT: health and disease SN: Study of the collection of ductless glands that secrete hormones which influence growth, gender, sexual maturity, and other attributes. TNR: 334 energy resources BT: natural resources NT: coal resources natural gas resources oil resources geothermal resources RT: economic geology UF: energy sources fossil fuels SN: Natural resources that are used for heat and power generation, including oil, natural gas, coal, and geothermal energy. TNR: 799 energy sources USE: energy resources engineering geology BT: engineering sciences RT: geology liquefaction remediation UF: engineering geology maps geotechnical properties maps rock mechanics maps SN: Branch of geology involved in the application of soil and rock mechanics, natural hazards, and other geological studies to the practice of engineering and construction. TNR: 337 engineering geology maps US+: maps and atlases engineering geology engineering sciences BT: sciences NT: engineering geology hydraulic engineering RT: instrument design and development mining hazards scientific careers UF: engineering seismology SN: Sciences involved in the application of scientific and mathematical principles to construction, machinery, mechanical design, mining and manufacturing processes and other practical activities. TNR: 339 engineering seismology US+: engineering sciences seismology entomology BT: invertebrate zoology RT: arachnids butterflies and moths insects pollinators SN: Branch of zoology involved in studying insects. TNR: 341 environmental analysis USE: environmental assessment environmental assessment BT: management methods NT: TMDL UF: environmental analysis environmental impact assessment SN: The evaluation of the status of a specific ecosystem or geographic area and how a proposed change in management or a proposed project will affect that status. TNR: 343 environmental chemistry USE: biochemistry environmental hazards USE: hazards environmental health (human) BT: health and disease NT: human environmental safety RT: human impacts social sciences toxic radionuclide contamination toxic trace element contamination virology UF: disease (human) health (human) human disease human health SN: Effects of the environment on human health. TNR: 345 environmental impact assessment USE: environmental assessment environmental management USE: natural resource management environmental planning USE: natural resource management environmental processes USE: ecological processes environmental toxicology USE: ecotoxicology eocene BT: paleogene TNR: 1631 eolian sediments USE: unconsolidated deposits Er USE: erbium erbium BT: chemical elements RT: lanthanide series elements UF: Er SN: Rare earth (lanthanide series) element with symbol Er and atomic number 68 TNR: 1447 erosion BT: geologic processes RT: geomorphology glaciology hydrology sedimentology watershed management scour UF: wind erosion dissolution sinkhole formation SN: The process whereby materials of the earth's crust are loosened, dissolved, or worn away and simultaneously moved from one place to another. TNR: 353 eruption USE: volcanic activity Es USE: einsteinium ESICs USE: USGS Earth Science Information Centers (ESICs) estuarine circulation US+: estuarine ecosystems water circulation estuarine currents US+: estuarine ecosystems water circulation estuarine ecosystem functions US+: estuarine ecosystems ecosystem functions estuarine ecosystems BT: aquatic ecosystems RT: aquatic biology ecology UF: estuarine circulation estuarine currents estuarine ecosystem functions SN: Biological communities and habitats within sea inlets or the zones where rivers meet the seas which are subject to tidal effects and the mixture of fresh and saltwater. TNR: 358 Eu USE: europium europium BT: chemical elements RT: lanthanide series elements UF: Eu SN: Rare earth (lanthanide series) element with symbol Eu and atomic number 63 TNR: 1450 eutrophication BT: ecological processes RT: ecology limnology oxygen content (water) SN: The process by which water becomes enriched with plant nutrients, most commonly phosphorus and nitrogen. TNR: 359 evaporation BT: atmospheric and climatic processes RT: transpiration water cycle UF: evapotranspiration SN: Transfer of water from a surface into the atmosphere. TNR: 1355 evapotranspiration US+: evaporation transpiration evolution BT: biological and physical processes UF: gene flow SN: Change in the genetic composition of populations of living organisms. TNR: 1702 exhibits (USGS) USE: USGS exhibits and facility tours exotic species USE: nonindigenous species expertise services (USGS) USE: USGS expertise services exploration USE: natural resource exploration exploration seismology US+: natural resource exploration seismology extinction and extirpation BT: ecological processes RT: ecology life sciences UF: extirpation SN: Extinction is the complete disappearance of a species from the earth. Extirpation is the complete disappearance (elimination) of a species from a given region, island, or area. TNR: 365 extirpation USE: extinction and extirpation F USE: fluorine facilities (USGS) USE: USGS facilities facility tours (USGS) USE: USGS exhibits and facility tours fall (season) USE: autumn false scorpions USE: arachnids farming USE: agriculture faulting (geologic) BT: fracture (geologic) SN: Movement of earth materials along fracture surfaces. TNR: 1700 fauna USE: animals faunal and floral census (microscopic) BT: laboratory methods RT: field inventory and monitoring microbiology micropaleontology microscopy UF: pollen analysis SN: Records of counts of the different microscopic species in a core, soil, sediment, rock or water sample to determine geologic age or other characteristic of the sample. Use for microscopic examinations. TNR: 370 fax-on-demand (USGS) USE: USGS fax-on-demand services Fe USE: iron fermentation USE: oxidation and reduction fermium BT: chemical elements RT: actinide series elements UF: Fm SN: Rare earth (actinide series) element with symbol Fm and atomic number 100 TNR: 1453 ferns and fern allies BT: vascular plants RT: botany SN: Spore-bearing, vascular plants having leaves known as fronds. TNR: 372 field centers (USGS) USE: USGS field centers field experiments BT: field methods NT: tracer study SN: Deliberate arrangement of objects and events in the field to observe the behavioral response of natural systems or organisms. TNR: 374 field inventory and monitoring BT: field methods NT: acoustic methods borehole logging CTD measurement ecosystem monitoring electromagnetic surveying handheld field spectroscopy seismic methods stream-gage measurement telemetry tiltmeter measurement video monitoring vocalization methods animal and plant census optical methods gravimeter measurement magnetometer measurement tomography RT: faunal and floral census (microscopic) field monitoring stations UF: baseline characterization field monitoring field observation inventory ocean current measurement ocean monitoring ocean wave measurement reconnaissance river discharge monitoring volcano monitoring weather monitoring weather observations precipitation measurement rainfall measurement snowfall measurement SN: Repeated observation or sampling at a site, on a scheduled or event basis, for study and analysis. In general, this category excludes sampling programs in which materials are obtained in the field and brought back to a laboratory for study and analysis. TNR: 375 field methods BT: methods NT: field experiments field inventory and monitoring field sampling geolocation measurement real-time monitoring and reporting SN: Research procedures and instrumental means to measure, collect data and samples, and observe in the natural areas where the materials, phenomena, structures, or species being studied occur. TNR: 376 field monitoring USE: field inventory and monitoring field monitoring stations BT: topics RT: field inventory and monitoring UF: benchmarks field stations seismic monitoring stations stream gaging stations SN: Locations where USGS scientists or their collaborators make measurements of natural phenomena. TNR: 1359 field observation USE: field inventory and monitoring field sampling BT: field methods NT: animal tracking capturing (animals) drilling and coring plant and animal tagging plot sampling sexing (plants & animals) specimen collecting transect sampling trenching water sampling UF: fish inventories SN: Collecting pieces or specimens or making measurements or observations at determined intervals or areas. Results may be used as representative of the whole research area or population. TNR: 379 field stations USE: field monitoring stations field trip guidebooks USE: guidebooks fire control BT: natural resource management NT: controlled fires RT: controlled fires UF: fire prevention SN: Human intervention to restrict or prevent fires in forests and grasslands. TNR: 1357 fire damage BT: habitat alteration UF: composite burn index normalized burn ratio SN: Destruction of surficial materials and vegetation by burning. TNR: 1378 fire preparedness US+: fires hazard preparedness fire prevention USE: fire control fires BT: biological and physical processes RT: atmospheric sciences controlled fires ecology hazards human impacts UF: fire preparedness fires (uncontrolled) wildfires SN: Combustion, marked by flames or intense heat, in natural settings, often ignited by lightning or human activities. For fires set as part of natural resource management, use 'controlled fires'. TNR: 384 fires (controlled) USE: controlled fires fires (uncontrolled) USE: fires fish BT: vertebrates RT: ichthyology UF: fish inventories fishes anadromous fish diadromous fish SN: Cold-blooded aquatic vertebrates with fins for swimming, gills for breathing, and usually scales. TNR: 387 fishery management BT: biological population management SN: Controlling or directing numbers and life conditions of fish living in a specific locality to achieve a selected goal. TNR: 390 fishery resources BT: natural resources NT: commercial fishery resources inland fishery resources marine fishery resources recreational fishery resources subsistence fishery resources RT: aquaculture aquatic biology ichthyology marine biology overfishing SN: The stock of anadromous, marine, and freshwater fish in fishing areas of commercial, subsistence, and recreational value. TNR: 391 fishes USE: fish fish farming USE: aquaculture fishing (recreational) USE: recreation fish inventories US+: fish field sampling fission-track dating BT: age estimation methods RT: geochronology radiometric dating UF: age dating (fission-track) fission-track method SN: Laboratory technique for determining the age of rocks and other geological materials by counts of spontaneous and induced fission tracks left by the radioactive isotope uranium-238. TNR: 393 fission-track method USE: fission-track dating flatworms BT: worms RT: invertebrate zoology SN: Soft flat worms of the phylum Platyhelminthes, which are often parasitic. Includes tapeworms and flukes. TNR: 395 flooding (controlled) USE: controlled flooding flood preparedness US+: hazard preparedness floods floods BT: hydrologic processes NT: storm surge RT: controlled flooding hazards hydrology surface water (non-marine) watershed management UF: bankfull stage flood preparedness SN: Relatively high water that overflows the natural or artificial banks of a stream or coastal area that submerges land not normally below water level. TNR: 398 flood stage USE: streamflow flora USE: plants (organisms) flow cytometry BT: chemical analysis RT: biochemistry cell biology SN: Laboratory technique to determine the amount of DNA in cells tagged by fluorescent dye by measuring the intensity of fluorescence under a laser beam. TNR: 400 flowering plants BT: vascular plants RT: botany SN: Plants known as angiosperms which periodically produce flowers which have various parts including sepals, petals, stamens, and carpels. TNR: 401 fluid dynamics USE: hydrodynamics fluid migration USE: ground-water flow fluorine BT: chemical elements RT: halogen elements UF: F SN: Halogen element with symbol F and atomic number 9 TNR: 1454 fluvial processes USE: streamflow flyways US+: biogeography migration (organisms) Fm USE: fermium folding (geologic) BT: deformation (geologic) RT: structural geology tectonic processes UF: crenulation (geologic) SN: A property of geologic structures to bend or curve from the planar layers. TNR: 403 foliation (geologic) BT: geologic structure RT: glaciation structural geology tectonic processes SN: The property of rocks or glaciers splitting into thin layers or plates due to the orientation of crystals and dynamic movement. TNR: 404 food chain USE: food web food cycle USE: food web food web BT: nutrient cycling RT: biochemistry ecology UF: food chain food cycle trophic level dynamics trophic relationships SN: The complex intertwining of the interrelated food chains in an ecosystem. TNR: 407 foraminifera USE: protists foreign species USE: nonindigenous species forest ecosystems BT: terrestrial ecosystems RT: ecology forest resources UF: arboreal ecosystems coniferous forests ecosystems deciduous forest ecosystems mixed forest ecosystems taiga ecosystems SN: Biological communities and habitats in geographic areas with dense growths of trees and associated vegetation. TNR: 410 forest resources BT: natural resources RT: botany ecology forest ecosystems UF: forestry SN: Trees and associated vegetation available for human use. Use for timber and other forest resources with economic value. TNR: 411 forestry USE: forest resources fossil fuels USE: energy resources fossils BT: rocks and deposits NT: ichnofossils RT: biostratigraphy micropaleontology paleontology trilobites UF: index fossils microfossils SN: Recognizable remains such as bones, shells, leaves, burrows, impressions, or tracks of past life on the earth. TNR: 414 Fr USE: francium fractal geometric methods USE: mathematical modeling fracture (geologic) BT: deformation (geologic) NT: faulting (geologic) RT: structural geology tectonic processes UF: cleavage (rock) jointing (geologic) SN: Break in a geologic structure including cracks, joints, and faults. TNR: 415 francium BT: chemical elements RT: alkali metal elements UF: Fr SN: Alkali metal element with symbol Fr and atomic number 87 TNR: 1457 free-air anomaly BT: gravitational field (earth) TNR: 1674 Frequently Asked Questions (FAQs) USE: USGS customer support and user feedback freshwater (ground) USE: ground water freshwater (surface) USE: surface water (non-marine) freshwater ecosystems BT: aquatic ecosystems RT: aquatic biology ecology ground water limnology surface water (non-marine) UF: lake ecosystems pond ecosystems river ecosystems spring ecosystems stream ecosystems SN: Biological communities and habitats that exist in lakes, rivers, ponds, and other bodies of water that are not salty. TNR: 419 fumarolic activity USE: volcanic gas emission fungi BT: organisms RT: mycology SN: Immobile organisms of the kingdom Fungi that lack chlorophyll and that obtain nutrients from other dead or living organisms. Fungi reproduce by spores and include yeasts, molds, smuts, and mushrooms. TNR: 420 Ga USE: gallium gadolinium BT: chemical elements RT: lanthanide series elements UF: Gd SN: Rare earth (lanthanide series) element with symbol Gd and atomic number 64 TNR: 1459 gage-height monitoring USE: stream-gage measurement gage height USE: streamflow gallium BT: chemical elements RT: metal elements UF: Ga SN: Metalloid element with symbol Ga and atomic number 31 TNR: 1460 game management BT: wildlife population management RT: wildlife biology SN: Scientific monitoring and control of hunted wildlife. TNR: 422 game species BT: organism groupings (non-taxonomic) RT: vertebrate zoology wildlife biology SN: Species of wild animals that are hunted for food or sport. TNR: 423 gamma-ray logging BT: borehole logging RT: stratigraphy SN: Recording of the measurements of natural gamma radiation emitted from the rocks in a borehole to study the subsurface structures. TNR: 424 gamma-ray spectrometric surveying USE: aeroradiometric surveying gas chromatography BT: chromatography RT: biochemistry geochemistry SN: Chromatographic technique used to separate or partition the components of a mixture. Solid and liquid samples are vaporized and passed through a column containing a liquid that differentially absorbs the molecules. TNR: 426 gas hydrate resources BT: natural gas resources RT: economic geology UF: methane hydrate resources SN: Deposits of a crystalline solid in which water molecules trap gas molecules, usually methane, in a cagelike structure known as a clathrate occurring in sediments overlain by cold deep water. TNR: 427 gazetteers BT: catalogs and indexes RT: geographic names SN: Indexed collections of geographic names. TNR: 1720 Gd USE: gadolinium Ge USE: germanium gemology USE: mineralogy gem resources BT: nonmetallic mineral resources RT: economic geology mineralogy SN: Deposits of rare minerals prized for their color, durability, sparkle, and clarity when cut and polished and used as ornaments or jewelry. TNR: 429 gene flow USE: evolution gene sequencing USE: DNA sequencing genetic diversity BT: biodiversity NT: genotype UF: conservation genetics SN: Measure of the variety of genes within a population pool in a given area. TNR: 432 genetics BT: life sciences RT: DNA sequencing molecular biology polymerase chain reaction UF: heredity SN: Branch of biology that deals with heredity or the passing of traits in living organisms from one generation to the next. TNR: 433 genome USE: DNA sequencing genotype BT: genetic diversity SN: Genetic characteristics of an individual organism. TNR: 1361 geochemical anomaly maps US+: geochemistry maps and atlases geochemical processes BT: biological and physical processes NT: biodegradation ore formation oxidation and reduction reaction transport sorption carbon sequestration RT: geochemistry soil formation biogeochemical cycling SN: Processes affecting the amount, distribution, or structure of chemical elements in air, water, soil, rocks, and minerals. TNR: 435 geochemical surveys USE: chemical analysis geochemistry BT: earth sciences NT: soil chemistry water chemistry RT: atomic absorption analysis biogeochemical cycling carbon cycling carbon isotope analysis chemical analysis chromatography earth history gas chromatography geochemical processes isotopic analysis light stable isotope analysis liquid chromatography mass spectroscopy metamorphism (geological) neutron activation analysis oxygen isotope analysis particle-beam spectroscopy tritium analysis UF: chemistry (Earth sciences) geochemical anomaly maps SN: Study of the distribution of chemical elements and natural compounds on the earth and in the atmosphere and the chemical processes that affect the earth. TNR: 437 geochronology BT: geology RT: carbon-14 analysis fission-track dating radiometric dating rubidium-strontium analysis stratigraphy tree ring analysis uranium-lead analysis uranium-thorium analysis SN: Study of the age of the earth by dating geological formations, rocks, and fossils. TNR: 438 geodata USE: geospatial datasets geodesy BT: geophysics RT: geography land surveying SN: Branch of science dealing with measuring the earth or large areas of the earth for making maps, determining the size and shape of the earth, and correlating gravitational, geological, and magnetic surveys of the earth. TNR: 440 geographic boundaries USE: administrative and political boundaries geographic coordinate systems USE: map coordinate systems geographic information sciences USE: geography geographic information system (GIS) datasets USE: geospatial datasets geographic information systems (GIS) BT: information system design and development RT: decision support methods geography geolocation measurement geospatial datasets GPS measurement information management methods information sciences map coordinate systems UF: GIS SN: Computer software that allows geospatially referenced data to be linked to geographic features. Use this term only for information that is about GIS and not for the use of GIS in applications and projects. TNR: 445 geographic names BT: culture and demographics RT: gazetteers SN: Names by which cultural and geographic features are known. Generally to be used for collections of names stored in gazetteers. TNR: 1719 geography BT: earth sciences NT: cartography paleogeography RT: administrative and political boundaries aeromagnetic surveying aeroradiometric surveying altimetry measurement AVHRR bathymetry measurement cadastral and legal land descriptions culture and demographics geodesy geographic information systems (GIS) geolocation measurement GPS measurement hyperspectral imaging IFSAR image analysis infrared imaging land surface characteristics land surveying land use change LIDAR map coordinate systems microwave imaging multispectral imaging panchromatic imaging radar imaging remote sensing SLAR SMMR spatial analysis SSM/I thermal imaging topography topological analysis visible light imaging UF: geographic information sciences SN: Study of the earth's landforms, topography, and climate, the distribution of flora and fauna, and the distribution, culture, and activities of human populations. TNR: 447 geohistory USE: geologic history geohydrology USE: hydrogeology geolocation measurement BT: field methods NT: altimetry measurement bathymetry measurement GPS measurement land surveying RT: geographic information systems (GIS) geography UF: location measurement navigating orienteering SN: Methods for establishing a geographic location on the surface of the earth. TNR: 450 geologic age USE: geologic time periods geological oceanography USE: marine geology geologic contacts BT: stratigraphic sections NT: unconformities RT: stratigraphy UF: contacts (geologic) SN: Junctions of two different rock formations varying by type or age of rock, including faults, unconformities, and bedding planes. TNR: 452 geologic formations USE: bedrock geologic units geologic hazards USE: hazards geologic history BT: earth characteristics NT: biostratigraphy earth history lithostratigraphy RT: geology paleontology paleoseismology stratigraphy UF: chronostratigraphy geohistory SN: Record (and inferred reconstruction) of the origin and development of the earth since its formation. TNR: 455 geologic maps US+: maps and atlases geology geologic processes BT: biological and physical processes NT: diagenesis earthquakes erosion glaciation heat flow (earth) hydrothermal processes isostasy land subsidence liquefaction metamorphism (geological) sediment transport sedimentation tectonic processes volcanic activity earth tides deformation (geologic) soil formation magnetic storms mass wasting RT: geology hydrology tsunamis UF: lithification SN: All types of processes involving geological structures. TNR: 451 geologic sections USE: stratigraphic sections geologic structure BT: earth characteristics NT: foliation (geologic) lineation (geologic) structure contours RT: earth structure stratigraphic sections structural geology deformation (geologic) SN: General position of rocks in an area, and geometrical relationships among rocks. TNR: 459 geologic time USE: geologic time periods geologic time periods BT: time periods NT: phanerozoic precambrian UF: geologic age geologic time TNR: 1634 geologic time scales BT: terminologies and classifications SN: Named divisions of geologic time used to specify relationships among geologic units and structural features TNR: 1745 geologic units USE: stratigraphic sections geology BT: earth sciences NT: economic geology geochronology geomorphology hydrogeology marine geology mineralogy petrology sedimentology stratigraphy structural geology volcanology RT: drilling and coring earth history engineering geology geologic processes geologic history metamorphism (geological) UF: geologic maps subsurface maps SN: Study of the planet earth, its composition, structure, physical and chemical processes, and history since its origin. TNR: 464 geomagnetic field USE: magnetic field (earth) geomagnetics USE: magnetic field (earth) geomagnetic storms USE: magnetic storms geomagnetism USE: magnetic field (earth) geomorphology BT: geology RT: bathymetry erosion land subsidence land surface characteristics landslides topography UF: speleology SN: Branch of geology dealing with surface land features and the processes that create and change them. TNR: 468 geophysical maps US+: maps and atlases geophysics geophysics BT: earth sciences NT: geodesy marine geophysics seismology tectonophysics RT: borehole logging borehole temperature logging core (earth) Curie temperature analysis gravitational field (earth) heat flow (earth) inner core (earth) isostasy laboratory-induced magnetization analysis magnetic field (earth) magnetic hysteresis analysis magnetic susceptibility analysis mantle (earth) metamorphism (geological) natural remanent magnetization analysis outer core (earth) paleomagnetic analysis UF: geophysical maps SN: Branch of geology studying the physical characteristics and phenomena of the earth and its atmosphere. TNR: 470 geosciences USE: earth sciences geospatial analysis BT: spatial analysis RT: image analysis topological analysis SN: Detailed study of information such as measurements, counts, and computations as a function of geographical location. TNR: 472 geospatial data USE: geospatial datasets geospatial datasets BT: datasets RT: geographic information systems (GIS) hydrographic datasets topography UF: DLG GIS datasets cartographic data (digital) digital cartographic data digital cartographic datasets digital line graphs geodata geographic information system (GIS) datasets geospatial data SN: Collections of related digital information that are geographically referenced. TNR: 474 geostatistics USE: statistical analysis geotechnical properties maps US+: engineering geology maps and atlases geothermal resources BT: energy resources RT: hydrogeology volcanology SN: Energy resources related to the earth's internal heat, commonly applied to springs or vents discharging hot water or steam. TNR: 477 geothermics USE: heat flow (earth) germanium BT: chemical elements RT: metal elements UF: Ge SN: Metalloid element with symbol Ge and atomic number 32 TNR: 1463 GIS USE: geographic information systems (GIS) GIS datasets USE: geospatial datasets glacial geology USE: glaciology glaciation BT: geologic processes RT: foliation (geologic) glaciology snow and ice cover SN: The geologic processes involved in the formation, movement, changes, and effects of large ice masses (glaciers). TNR: 482 glaciers USE: snow and ice cover glaciology BT: earth sciences RT: drilling and coring erosion glaciation isostasy snow and ice cover UF: cryology glacial geology SN: Science dealing with the features, origins, processes, and properties of snow, ice, glaciers, and ice sheets. TNR: 484 global change BT: topics NT: global warming RT: atmospheric sciences climate change ecology ocean sciences sea-level change SN: Changes in global environmental systems, including climate, land, oceans, fresh water, atmosphere and ecology throughout earth's history. TNR: 485 global climate change USE: climate change global positioning measurement USE: GPS measurement global warming BT: global change RT: atmospheric sciences climate change ecology ocean sciences SN: Increase in the average temperature of the earth's surface, often used to refer to the warming predicted as a result of anthropogenic emissions of greenhouse gases. TNR: 488 glossaries USE: terminologies and classifications gold BT: chemical elements RT: metal elements UF: Au SN: Metal element with symbol Au and atomic number 79 TNR: 1464 gold ores BT: metallic ores RT: economic geology mineralogy SN: Mineral deposits from which gold, a heavy, yellow, malleable metal, valuable as ornaments, jewelry, or coinage, can be extracted. TNR: 490 governmental units USE: administrative and political boundaries GPS measurement BT: geolocation measurement RT: geographic information systems (GIS) geography UF: global positioning measurement SN: Determination of distance and location using instruments receiving signals from the Global Positioning System, a system of satellites for identifying earth locations. TNR: 492 grain-size analysis BT: laboratory methods NT: sieve-size analysis RT: sedimentology UF: grainsize analysis granulometry particle-size analysis SN: Method of studying soils, sediments, sands, or rock by determining the size, distribution, and proportion of selected particles. TNR: 493 grainsize analysis USE: grain-size analysis grants (USGS) USE: USGS contracts and grants granulometry USE: grain-size analysis grasses USE: vegetation grassland ecosystems BT: terrestrial ecosystems RT: ecology UF: mixed grass ecosystems plains ecosystems prairie ecosystems short grass ecosystems tall grass ecosystems SN: Biological communities and habitats with ground cover of grasses and other herbaceous plants, but few trees. Examples include prairies, meadows, and savannas. TNR: 499 gravel deposits BT: unconsolidated deposits RT: economic geology nonmetallic mineral resources sedimentology SN: Alluvial accumulations of small unconsolidated rock fragments, such as pebbles and cobbles, used in construction as fill, ground cover, or aggregate for concrete. TNR: 500 gravimeter measurement BT: field inventory and monitoring UF: gravimetric methods gravimetry SN: Use of a specialized instrument for measuring the earth's gravity at a given location. TNR: 1668 gravimetric methods USE: gravimeter measurement gravimetry USE: gravimeter measurement gravitational field (earth) BT: earth characteristics NT: isostatic anomaly free-air anomaly bouguer anomaly RT: geophysics UF: gravity anomaly maps gravity field gravity SN: Region or space around earth's mass which exerts a force that mutually attracts other masses in proportion to the product of the two masses and the distance between them. TNR: 501 gravity USE: gravitational field (earth) gravity anomaly maps US+: gravitational field (earth) maps and atlases gravity field USE: gravitational field (earth) gray water USE: wastewater use greenhouse effect BT: atmospheric and climatic processes RT: greenhouse gases SN: Local, regional, or global warming in the atmosphere due to the higher heat capacity of certain gases such as carbon dioxide, methane, and ozone. TNR: 1704 greenhouse gases BT: atmospheric composition RT: atmospheric sciences climate change ozone layer greenhouse effect SN: Atmospheric gases, including carbon dioxide, fluorocarbons, methane, nitrous oxide, sulfur hexafluoride, ozone, and water vapor, that trap radiant (infrared) energy keeping the earth's surface warmer than it would otherwise be. TNR: 506 grey water USE: wastewater use grid coordinate systems USE: map coordinate systems grizzly bears USE: bears ground-water USE: ground water ground-water/surface-water interaction USE: ground-water and surface-water interaction ground-water and surface-water interaction BT: hydrologic processes UF: aquifer-surface water interaction ground water/surface water interaction ground-water/surface-water interaction hyporheic zone processes surface water/ground water interaction surface-water/ground-water interaction SN: Traditionally, management of water resources has focused on surface water or ground water as if they were separate entities. As development of land and water resources increases, it is apparent that development of either of these resources affects the quantity and quality of the other. Nearly all surface-water features (streams, lakes, reservoirs, wetlands, and estuaries) interact with ground water. These interactions take many forms. In many situations, surface-water bodies gain water and solutes from ground-water systems and in others the surface-water body is a source of ground-water recharge and causes changes in ground-water quality. As a result, withdrawal of water from streams can deplete ground water or conversely, pumpage of ground water can deplete water in streams, lakes, or wetlands. Pollution of surface water can cause degradation of ground-water quality and conversely pollution of ground water can degrade surface water. TNR: 1692 ground-water flow BT: hydrologic processes RT: ground water hydrogeology water cycle reaction transport UF: fluid migration ground-water flow modeling ground-water movement groundwater flow SN: Movement of subsurface water in the saturated zone from areas of recharge to areas of discharge. TNR: 514 ground-water flow modeling USE: ground-water flow ground-water level BT: ground water NT: unsaturated zone RT: surface-water level UF: aquifer level potentiometric surface water table SN: Depth in a well or aquifer at which ground water occurs. TNR: 1344 ground-water movement USE: ground-water flow ground-water quality BT: water quality RT: ground water hydrology water chemistry UF: groundwater quality SN: Fitness of subsurface water for use based on its composition and properties. TNR: 518 ground motion USE: earthquake occurrences ground motion maps US+: maps and atlases earthquake occurrences ground transportation USE: transportation groundwater USE: ground water ground water BT: water resources NT: ground-water level RT: freshwater ecosystems ground-water flow ground-water quality hydrogeology UF: freshwater (ground) ground-water groundwater water subsurface SN: All water that exists beneath the land surface, but more commonly applied to water in fully saturated soils and geologic formations. TNR: 513 ground water/surface water interaction USE: ground-water and surface-water interaction groundwater flow USE: ground-water flow groundwater flow modeling USE: mathematical modeling groundwater geology USE: hydrogeology groundwater quality USE: ground-water quality guidebooks BT: reports UF: field trip guidebooks SN: Books intended to direct and instruct travelers in a given area and often geared to special interests, such as observing local birds, understanding geological features, or locating endemic plants. TNR: 519 guidelines USE: reports gymnosperms BT: vascular plants RT: botany SN: Seed-bearing woody vascular plants, such as the conifers (pine, spruce, fir, etc.), whose seeds are not enclosed in an ovary or fruit, but are exposed. TNR: 521 H USE: hydrogen H5N1 USE: avian influenza habitat alteration BT: ecological processes NT: fire damage RT: ecology UF: habitat destruction habitat fragmentation SN: Natural or human-related changes in the environments where plants and animals live. TNR: 522 habitat destruction USE: habitat alteration habitat fragmentation USE: habitat alteration habitats BT: population and community ecology RT: ecosystems SN: Parts of the physical environment where plants and animals live. Use in combination with terms from "organisms" and "organism groupings (informal)" to indicate the topic of a species or group of species' habitat. TNR: 525 hadean BT: precambrian TNR: 1635 hafnium BT: chemical elements RT: metal elements UF: Hf SN: Metal element with symbol Hf and atomic number 72 TNR: 1466 halogen elements BT: chemical element groups RT: fluorine chlorine bromine iodine astatine TNR: 1467 hand-held field spectroscopy USE: handheld field spectroscopy handheld field spectroscopy BT: field inventory and monitoring UF: hand-held field spectroscopy SN: Use of portable equipment to measure spectral reflectance of materials in the field. TNR: 527 hardness (water) USE: water hardness harmful algal blooms US+: hazards algal blooms hassium BT: chemical elements RT: metal elements UF: Hs SN: Metal element with symbol Hs and atomic number 108 TNR: 1468 hazard mitigation USE: hazard preparedness hazard preparedness BT: management methods NT: earthquake preparedness aviation safety UF: early warning systems emergency response planning fire preparedness flood preparedness hazard mitigation landslide preparedness tsunami preparedness SN: Awareness of the consequences of hazards and actions to be taken before, during, or after hazards occur or are encountered. TNR: 530 hazards BT: topics RT: scour algal blooms desertification droughts earthquakes ecotoxicology fires floods human impacts landslides liquefaction mining hazards contamination and pollution social sciences storms tsunamis volcanic activity impact cratering magnetic storms UF: catastrophes disasters earthquake hazards emergency management resources environmental hazards geologic hazards harmful algal blooms SN: Potential dangers from both natural processes (e.g., earthquakes, floods, and climate change) and human impacts on the environment. TNR: 531 He USE: helium health (human) USE: environmental health (human) health and disease BT: topics NT: disease vectors environmental health (human) avian influenza RT: bacteriology endocrinology histology immunology life sciences parasitology pathology social sciences UF: disease nutrition SN: Normal and abnormal conditions of plant and animal bodies. Covers both human and non-human health and disease topics. For human health and disease, use the narrower term 'environmental health (human)'. TNR: 533 heat flow (earth) BT: geologic processes RT: geophysics UF: geothermics heatflow (earth) SN: Energy transferred by a difference in temperature through the surface of the earth. TNR: 534 heatflow (earth) USE: heat flow (earth) helium BT: chemical elements RT: noble gas elements UF: He SN: Noble gas element with symbol He and atomic number 2 TNR: 1470 herbicide contamination USE: pesticide and herbicide contamination herbivores BT: consumers (organisms) RT: ecology zoology SN: Animals that eat chiefly plants or their products, such as seeds, nectar, and fruit. TNR: 537 heredity USE: genetics herpetology BT: vertebrate zoology RT: amphibians reptiles SN: Branch of zoology concerned with the study of reptiles and amphibians. TNR: 539 Hf USE: hafnium Hg USE: mercury high-pressure liquid chromatography USE: liquid chromatography hiking USE: recreation histology BT: anatomy and physiology RT: health and disease SN: Branch of anatomy concerned with the microscopic structure of plant and animal tissue. TNR: 540 Ho USE: holmium holmium BT: chemical elements RT: lanthanide series elements UF: Ho SN: Rare earth (lanthanide series) element with symbol Ho and atomic number 67 TNR: 1474 holocene BT: quaternary TNR: 1636 horizontal datums USE: map coordinate systems horseshoe crabs BT: arthropods RT: invertebrate zoology SN: Marine arthropods, usually classed as Merostomata, which have a broad crescent (horseshoe-shaped) cephalothorax. TNR: 543 horticulture USE: agriculture HPAI USE: avian influenza HPLC USE: liquid chromatography Hs USE: hassium human disease USE: environmental health (human) human environmental safety BT: environmental health (human) RT: social sciences UF: safety issues (human) SN: Monitoring and managing potentially harmful factors in the environment for human safety. TNR: 546 human health USE: environmental health (human) human impacts BT: topics NT: deforestation land use change mining hazards overfishing overgrazing abandoned mines and quarries waste treatment and disposal dredging RT: acid deposition ecology ecotoxicology environmental health (human) fires hazards invasive species land subsidence social sciences contamination and pollution SN: The effects, intentional or unintentional, beneficial or harmful, direct or indirect, which human activities have upon the environment and living things. TNR: 548 hunting USE: recreation hurricanes BT: storms RT: meteorology UF: typhoons SN: Severe cyclones, or revolving storms, originating over the equatorial regions of the earth, accompanied by torrential rain, lightning, and winds with a speed greater than 74 miles per hour. TNR: 549 hydraulic engineering BT: engineering sciences RT: agricultural water use commercial water use domestic water use industrial water use instream water use irrigation mining water use offstream water use power generation water use wastewater use water use water resource management dredging UF: hydraulic models hydraulics SN: Branch of engineering which applies the physical properties of fluids, such as flow and pressure, to the design and use of machinery, pumps, pipelines, etc. TNR: 550 hydraulic models USE: hydraulic engineering hydraulics USE: hydraulic engineering hydroacoustics USE: acoustic doppler current profiling hydrodynamics BT: hydrology UF: fluid dynamics SN: Principles of fluid dynamics applied to water bodies. TNR: 1678 hydroelectric power generation water use USE: power generation water use hydrogen BT: chemical elements RT: alkali metal elements UF: H SN: Alkali metal element with symbol H and atomic number 1 TNR: 1476 hydrogeology BT: geology RT: geothermal resources ground water ground-water flow hydrothermal processes water resources hydrology UF: geohydrology groundwater geology hydrographic sections SN: Study of subsurface waters and geologic aspects of surface waters. TNR: 554 hydrographic datasets BT: datasets RT: geospatial datasets SN: Datasets for graphs showing variation of water elevation, velocity, streamflow, or other property of water with respect to time. TNR: 555 hydrographic sections USE: hydrogeology hydrologic cycle USE: water cycle hydrologic maps US+: hydrology maps and atlases hydrologic processes BT: biological and physical processes NT: runoff water cycle floods ground-water flow streamflow water circulation percolation saltwater intrusion scour ground-water and surface-water interaction RT: precipitation (atmospheric) TNR: 1667 hydrology BT: earth sciences NT: hydrodynamics RT: agricultural water use commercial water use domestic water use erosion floods geologic processes ground-water quality hydrothermal processes industrial water use instream water use irrigation limnology marine water quality meteorology mining water use nutrient content (water) ocean sciences offstream water use oxygen content (water) power generation water use precipitation (atmospheric) stream discharge river reaches river systems salinity sediment transport streamflow stream-gage measurement surface water (non-marine) surface water quality suspended material (water) wastewater use water circulation water hardness water pH water properties water quality water resources water sampling water temperature water use wetland functions hydrogeology UF: hydrologic maps SN: Branch of earth science that deals with water as it occurs in the atmosphere, on the surface of the ground, and underground. TNR: 560 hydrophytes USE: aquatic vegetation hydrosphere USE: water resources hydrothermal processes BT: geologic processes RT: hydrogeology hydrology SN: Natural phenomena relating to heated water generated by igneous activity. TNR: 562 hyperspectral imaging BT: remote sensing RT: geography SN: Multispectral imaging technique that records many bands of imagery at very narrow bandwidths. TNR: 563 hyporheic zone processes USE: ground-water and surface-water interaction hypoxia USE: oxygen content (water) hysteresis USE: magnetic hysteresis analysis I USE: iodine ice USE: snow and ice cover ice age USE: pleistocene ice core sampling US+: drilling and coring snow and ice cover ice storms BT: storms SN: Storms in which falling snow or rain freezes on contact with surfaces on the ground. TNR: 568 ichnofossils BT: fossils RT: biostratigraphy paleontology UF: trace fossils SN: Fossilized remains of the traces of animal activity from different geologic time periods including burrows, tracks, trails, borings, and other features found in sedimentary structures. TNR: 569 ichthyology BT: vertebrate zoology RT: commercial fishery resources fish fishery resources inland fishery resources marine fishery resources overfishing recreational fishery resources SN: Branch of zoology concerned with the study of fish. TNR: 570 ICP-AES USE: atomic emission spectroscopy IFSAR BT: remote sensing RT: geography UF: Interferometric Synthetic Aperture Radar (IFSAR) SAR interferometry InSAR SN: Interferometric comparison of radar reflectance imagery of the same area at different times to determine changes in the land surface, typically from a space-borne sensor. TNR: 571 igneous rocks BT: rocks and deposits NT: volcanic rocks Plutonic rocks RT: petrology SN: Rocks formed from melted rock that has cooled and solidified. TNR: 572 image analysis BT: computational methods RT: geography geospatial analysis spatial analysis SN: Pattern analysis of the shapes and textures of images to identify features and derive information about them. TNR: 574 image collections BT: product types UF: aerial photos air photos orthoimagery orthophotographs AVHRR images LIDAR images Landsat images aerial photographs photographs pictures scientists-at-work photographs remote-sensing data remote-sensing images satellite images SN: Visible representations of objects produced by optical or spectral instruments or cameras. TNR: 575 immunology BT: anatomy and physiology RT: health and disease SN: Branch of biology which studies the body's production of lymphocytes, antibodies, and macrophages in response to foreign substances or pathogenic organisms. TNR: 576 impact cratering BT: biological and physical processes RT: hazards planetary bodies UF: bolide impact meteor impact comet impact asteroid impact SN: Impact of extraterrestrial objects such as asteroids, comets, and meteorites on Earth. TNR: 1718 impoundment USE: water resource management In USE: indium in-stream water use USE: instream water use indexes USE: catalogs and indexes index fossils USE: fossils indicator species observation USE: ecosystem monitoring indigenous species USE: native species indium BT: chemical elements RT: metal elements UF: In SN: Metalloid element with symbol In and atomic number 49 TNR: 1479 inductively coupled plasma-atomic emission spectrometry USE: atomic emission spectroscopy industrial minerals USE: mineral resources industrial pollution BT: contamination and pollution NT: mine drainage RT: abandoned mines and quarries UF: polychlorinated biphenyls PCBs SN: Introduction of harmful substances into the environment by manufacturing, power generation, mining, or material processing. TNR: 1723 industrial water use BT: offstream water use RT: hydraulic engineering hydrology SN: Use of water for industrial purposes such as fabrication, processing, washing, and cooling, and including such industries as steel, chemical and allied products, paper and allied products, mining, and petroleum refining. TNR: 581 inert gases USE: noble gas elements infiltration (water) USE: percolation informal education (USGS) USE: USGS lifelong learning programs information centers (USGS) USE: USGS information services information management methods BT: management methods RT: geographic information systems (GIS) UF: data management SN: Activities focused on scientific information creation, description, storage, and retrieval for evaluation and analysis. TNR: 584 information sciences BT: sciences NT: biological informatics computer science RT: geographic information systems (GIS) information system design and development metadata development scientific careers SN: Sciences dealing with the compilation, processing, classification, display, transmission, storage, and retrieval of recorded knowledge. TNR: 585 information services (USGS) USE: USGS information services information system design and development BT: topics NT: geographic information systems (GIS) metadata development RT: information sciences SN: Use for the design and development of information systems. Do not use for general cases in which information systems are part of the activity. TNR: 587 infrared imaging BT: remote sensing NT: AVHRR AVIRIS RT: geography SN: Method of remote sensing in which optical sensors produce visible representations of infrared rays or radiated heat from the observed objects and the temperature variations are represented by different colors in the image. TNR: 588 inland fishery resources BT: fishery resources RT: aquatic biology ichthyology SN: Stocks of fish available to be taken in lakes, streams, ponds, rivers, and other inland bodies of water. TNR: 589 inner core (earth) BT: core (earth) RT: geophysics SN: The solid interior part of the earth's core, presumed to be composed principally of iron with an alloy of about 10 percent oxygen, sulfur, or nickel, or perhaps some combination of these three elements. The inner core is about 1221 kilometers thick. TNR: 590 InSAR USE: IFSAR insecticide contamination USE: pesticide and herbicide contamination insects BT: arthropods NT: butterflies and moths bees and wasps RT: entomology UF: bugs SN: Small arthropod animals of the class Insecta with bodies in 3 segments (head, thorax, and abdomen). They have 3 pairs of legs, 2 antennae, and usually one or two pairs of wings. Includes flies, mosquitoes, beetles, butterflies, bees, crickets, and dragonflies. TNR: 591 instream water use BT: water use NT: power generation water use wastewater use RT: hydraulic engineering hydrology UF: in-stream water use SN: Water that is used, but not withdrawn, from a surface-water or groundwater source for such purposes as hydroelectric power generation, navigation, water-quality improvement, fish propagation, and recreation. Sometimes called nonwithdrawal use or in-channel use. TNR: 592 instrument design and development BT: topics RT: engineering sciences UF: tool development SN: Includes the design and development of software for a particular instrument. TNR: 594 insular ecology USE: island ecosystems interactive map servers (USGS) USE: USGS map servers interagency programs (USGS) USE: USGS interagency programs Interferometric Synthetic Aperture Radar (IFSAR) USE: IFSAR international programs (USGS) USE: USGS international programs internships (USGS) USE: USGS internships interstices USE: porosity introduced species USE: nonindigenous species intrusive rocks USE: Plutonic rocks invader species USE: invasive species invasive species BT: nonindigenous species RT: biodiversity ecology human impacts life sciences UF: biological invasions invader species SN: Plant, animal, or microbe species that is non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm, or harm to human health. TNR: 602 inventory USE: field inventory and monitoring invertebrate paleontology BT: paleontology RT: bryozoans and brachiopods conodonts invertebrate zoology invertebrates trilobites SN: Branch of paleontology which deals with fossil animals without backbones. TNR: 604 invertebrates BT: animals NT: arthropods bryozoans and brachiopods coelenterates conodonts echinoderms mollusks sponges worms tunicates RT: invertebrate paleontology invertebrate zoology SN: Animals having no backbone or spinal column, such as insects, mollusks, crustaceans, worms, and similar organisms. TNR: 606 invertebrate zoology BT: zoology NT: entomology RT: arachnids arthropods bryozoans and brachiopods coelenterates crustaceans echinoderms flatworms horseshoe crabs invertebrate paleontology invertebrates mollusks ostracodes roundworms segmented worms shellfish sponges worms SN: Branch of biology dealing with animals having no backbones or spinal columns. TNR: 605 iodine BT: chemical elements RT: halogen elements UF: I SN: Halogen element with symbol I and atomic number 53 TNR: 1481 Ir USE: irridium iron BT: chemical elements RT: metal elements UF: Fe SN: Metal element with symbol Fe and atomic number 26 TNR: 1483 irridium BT: chemical elements RT: metal elements UF: Ir SN: Metal element with symbol Ir and atomic number 77 TNR: 1484 irrigation BT: agricultural water use RT: hydraulic engineering hydrology SN: Artificial application of water on lands to assist in the growing of crops and pastures or to maintain vegetative growth in recreational lands such as parks and golf courses. TNR: 607 island ecosystems BT: terrestrial ecosystems UF: insular ecology SN: Communities of living organisms on islands. TNR: 1706 isostasy BT: geologic processes RT: geophysics glaciology SN: Condition of equilibrium or buoyancy of the earth's crust above the mantle. TNR: 608 isostatic anomaly BT: gravitational field (earth) TNR: 1673 isotopic analysis BT: laboratory methods NT: light stable isotope analysis radiometric dating RT: biochemistry geochemistry SN: Experimental determination of the proportion of a given isotope (or isotopes) in a sample. TNR: 609 isotopic tracer study USE: tracer study jellyfish USE: coelenterates jointing (geologic) USE: fracture (geologic) journal articles USE: reports journals USE: reports jurassic BT: mesozoic TNR: 1638 K USE: potassium K-12 programs (USGS) USE: USGS K-12 programs K-Ar dating USE: potassium-argon analysis kayaking USE: recreation keystone species BT: organism groupings (non-taxonomic) SN: Species whose abundance and ecological role has a dramatic effect on the other species in an ecosystem. TNR: 615 Kr USE: krypton kriging BT: statistical analysis SN: Statistical analysis technique which uses interpolation to best predict unknown data values from data observed at known locations. TNR: 616 krypton BT: chemical elements RT: noble gas elements UF: Kr SN: Noble gas element with symbol Kr and atomic number 36 TNR: 1487 La USE: lanthanum laboratories (USGS) USE: USGS laboratories laboratory-induced magnetization analysis BT: paleomagnetic analysis RT: geophysics SN: Laboratory method to study rocks using magnetometers to measure remanent magnetic fields induced in the samples. TNR: 620 laboratory methods BT: methods NT: chemical analysis core analysis culturing (specimens) faunal and floral census (microscopic) grain-size analysis isotopic analysis meristics microscopy paleomagnetic analysis petrography plant and animal testing therapeutic methods tree ring analysis camera calibration age estimation methods SN: Experimental techniques to analyze and test samples in a place equipped and designed for the work. TNR: 619 laboratory reference materials USE: materials standards lahars BT: landslides RT: volcanic activity SN: Downslope flow of ash and rock debris resulting from volcanic activity. TNR: 1362 lake circulation USE: water circulation lake ecosystems USE: freshwater ecosystems land partitioning systems USE: cadastral and legal land descriptions Landsat images US+: image collections multispectral imaging landscape USE: land surface characteristics landslide maps US+: landslides maps and atlases landslide preparedness US+: hazard preparedness landslides landslides BT: mass wasting NT: lahars RT: geomorphology hazards landslide susceptibility assessment UF: avalanches debris avalanches debris flows landslide maps landslide preparedness mudflows rockfalls slides (land) SN: Downslope movement of rock, soil, or artificial fill under the influences of gravity. TNR: 639 landslide susceptibility assessment BT: risk assessment RT: landslides UF: landslide susceptibility maps slope stability slope stability maps SN: Estimation of the probability of occurrence and likely severity of landslides in a given area. TNR: 637 landslide susceptibility maps US+: maps and atlases landslide susceptibility assessment land subsidence BT: geologic processes RT: geomorphology human impacts UF: land subsidence maps SN: Settling, compaction, or caving in of land caused by subsurface mining, ground-water withdrawal, or pumping of oil and gas. TNR: 624 land subsidence maps US+: maps and atlases land subsidence land surface characteristics BT: earth characteristics RT: geography geomorphology sea-floor characteristics UF: landscape physiography SN: Features and attributes of earth's land surface. TNR: 626 land surveying BT: geolocation measurement RT: geodesy geography UF: surveying SN: Determining property boundaries, land area, elevations, and locations of features on the surface of the land by calculations based on the instrumental measurements of angles and distances or by use of global positional satellites. TNR: 627 land use and land cover BT: topics SN: The vegetation, water, natural surface, and cultural features on the land surface. TNR: 628 land use change BT: human impacts RT: desertification ecology geography social sciences UF: urbanization SN: Effect of changing land use patterns on ecological systems. TNR: 629 land use maps USE: maps and atlases La Nina USE: ocean-atmosphere interaction lanthanide series elements BT: rare earth elements RT: lanthanum cerium praseodymium neodymium prometium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium TNR: 1489 lanthanum BT: chemical elements RT: lanthanide series elements UF: La SN: Rare earth (lanthanide series) element with symbol La and atomic number 57 TNR: 1490 lava USE: volcanic rocks lava flows USE: volcanic activity lawrencium BT: chemical elements RT: actinide series elements UF: Lr SN: Rare earth (actinide series) element with symbol Lr and atomic number 103 TNR: 1491 laws and regulations BT: culture and demographics UF: legal processes legislation statutes SN: Legal statements of the government regarding actions people or corporations might undertake. TNR: 1684 leaching (analytical method) USE: chemical analysis lead BT: chemical elements RT: metal elements UF: Pb SN: Metalloid element with symbol Pb and atomic number 82 TNR: 1492 lead-210 dating USE: radiometric dating legal land descriptions USE: cadastral and legal land descriptions legal processes USE: laws and regulations legislation USE: laws and regulations lepidoptera USE: butterflies and moths Li USE: lithium libraries (USGS) USE: USGS libraries and archives lichens BT: organisms RT: mycology phycology SN: Plants that are composed of a fungus and an alga growing together symbiotically and often found growing on rocks or tree trunks. TNR: 647 LIDAR BT: remote sensing RT: geography UF: LIDAR images LIght Detection and Ranging (LIDAR) SN: LIDAR (LIght Detection and Ranging) is an airborne laser-ranging technique commonly used for acquiring high-resolution topographic data. TNR: 648 LIDAR images US+: image collections LIDAR life-long learning programs (USGS) USE: USGS lifelong learning programs life history USE: population and community ecology lifelong learning programs (USGS) USE: USGS lifelong learning programs life sciences BT: sciences NT: anatomy and physiology aquatic biology biochemistry botany cell biology developmental biology ecology ecotoxicology genetics marine biology microbiology molecular biology morphology (biological) mycology parasitology pathology systematics and taxonomy zoology RT: biodiversity biological informatics biological productivity biota decomposers disease vectors dispersal (organisms) endangered species endemic species extinction and extirpation health and disease invasive species migration (organisms) native species natural resources nonindigenous species organism groupings (non-taxonomic) organisms paleontology plant and animal tagging scientific careers sexing (plants & animals) UF: biological sciences biology SN: Branches of science that study living and fossil organisms. TNR: 650 LIght Detection and Ranging (LIDAR) USE: LIDAR light stable-isotope analysis USE: light stable isotope analysis light stable isotope analysis BT: isotopic analysis NT: beryllium isotope analysis carbon isotope analysis oxygen isotope analysis tritium analysis RT: biochemistry geochemistry UF: light stable-isotope analysis stable isotope analysis SN: Analytical technique using mass spectrometry to measure the different isotopic forms of low mass (light) elements such as oxygen, hydrogen, carbon, nitrogen and sulfur that occur in samples. TNR: 654 lignite resources USE: coal resources limnology BT: earth sciences RT: aquatic ecosystems bathymetry benthic ecosystems CTD measurement eutrophication freshwater ecosystems hydrology surface water (non-marine) surface water quality water resources SN: Scientific study of the physical and biological characteristics of inland bodies of water such as lakes and ponds. TNR: 657 lineaments USE: lineation (geologic) lineation (geologic) BT: geologic structure RT: structural geology tectonic processes UF: lineaments SN: Linear topographic feature on the earth's surface or in rocks. TNR: 660 liquefaction BT: geologic processes RT: engineering geology hazards SN: Physical process which can occur during an earthquake. Clay-free soil deposits (primarily sands and silts)temporarily lose strength and behave as viscuous fluids, resulting in ground failure. TNR: 661 liquid chromatography BT: chromatography RT: biochemistry geochemistry UF: HPLC high-pressure liquid chromatography SN: Chromatographic technique to separate or partition the components of a mixture in which samples are liquid and passed through a column. TNR: 662 lists of publications USE: catalogs and indexes lithification USE: geologic processes lithium BT: chemical elements RT: alkali metal elements UF: Li SN: Alkali metal element with symbol Li and atomic number 3 TNR: 1494 lithologic maps US+: maps and atlases rocks and deposits lithology USE: rocks and deposits lithosphere BT: crust (earth) NT: continental lithosphere oceanic lithosphere RT: mantle (earth) rocks and deposits tectonophysics SN: The solid outer zone of the earth comprising the crust and the upper layer of the mantle. TNR: 667 lithostratigraphy BT: geologic history RT: tephrochronology stratigraphy SN: Branch of stratigraphy dealing with the study of units of rock. Each unit is composed of a body of rock which is dominated by a certain lithology or similar color, mineralogic composition, and grain size. TNR: 668 littoral ecosystems USE: coastal ecosystems liverworts and hornworts BT: nonvascular plants RT: botany mosses SN: Simple green land plants of the phyla Bryophyta with leaves and a stem and always without roots. TNR: 669 livestock husbandry USE: agriculture livestock water use USE: agricultural water use location measurement USE: geolocation measurement loess USE: unconsolidated deposits long-term ecological monitoring BT: ecosystem monitoring RT: ecology SN: Data collection over a period of years or decades to assess changes in selected biological communities and habitats. TNR: 672 lower carboniferous USE: mississippian Lr USE: lawrencium Lu USE: lutetium luminescence dating BT: age estimation methods UF: optically-stimulated luminescence dating thermoluminescence dating TL/OSL dating SN: Dating methods that involve the analysis of the optical properties of minerals exposed to environmental radiation. Typically used to determine the age of subaerial exposure of surficial sediments. TNR: 1677 lutetium BT: chemical elements RT: lanthanide series elements UF: Lu SN: Rare earth (lanthanide series) element with symbol Lu and atomic number 71 TNR: 1497 macroinvertebrates BT: organism groupings (non-taxonomic) RT: aquatic biology SN: Invertebrate animals large enough to be studied without a microscope. TNR: 673 magma USE: Plutonic rocks magnesium BT: chemical elements RT: alkaline earth elements UF: Mg SN: Alkaline earth element with symbol Mg and atomic number 12 TNR: 1498 magnetic anomaly maps US+: magnetic field (earth) maps and atlases magnetic field USE: magnetic field (earth) magnetic field (earth) BT: earth characteristics RT: geophysics magnetic storms UF: geomagnetic field geomagnetics geomagnetism magnetic anomaly maps magnetic field magnetosphere SN: The magnetic region surrounding earth. It is generated by the dipolar characteristic of earth's core whereby earth itself acts as a great spherical magnet with poles near, but not exactly at, the North and South poles. TNR: 677 magnetic hysteresis analysis BT: paleomagnetic analysis RT: geophysics UF: hysteresis SN: Nondestructive evaluation of ferromagnetic materials. The evaluation is based on measurement of the variation of intensity of magnetization within an applied magnetic field due to changes in the magnetic domain structure of the materials under study. TNR: 678 magnetic storms BT: geologic processes RT: hazards magnetic field (earth) UF: geomagnetic storms SN: A period of time during which the earth\'s magnetic field varies rapidly. During magnetic storms, satellite electronics can be damaged through the build up and subsequent discharge of static electric charges and astronauts and high-altitude pilots can be subjected to increased levels of radiation. TNR: 1721 magnetic surveying US+: aeromagnetic surveying electromagnetic surveying magnetic susceptibility BT: magnetism SN: Degree to which a rock type or other earth material can acquire and retain the orientation and intensity of an applied magnetic field. TNR: 1742 magnetic susceptibility analysis BT: paleomagnetic analysis RT: geophysics SN: Nondestructive evaluation and location of magnetic materials in rock based on measuring the intensity of attraction of the materials to an induced magnetic field. Applications include geological and soil surveys, paleomagnetic studies, sedimentology, archaeological prospecting and core logging. TNR: 680 magnetism BT: earth material properties NT: remanent magnetism magnetic susceptibility SN: Strength and orientation of the permanent magnetic field in a given sample of an earth material TNR: 1741 magnetometer measurement BT: field inventory and monitoring UF: magnetometry SN: Use of specialized instruments designed to measure the earth's magnetic field at a given location. TNR: 1669 magnetometry USE: magnetometer measurement magnetosphere USE: magnetic field (earth) magnetotelluric sounding USE: electromagnetic surveying malacology USE: zoology mammalogy BT: vertebrate zoology RT: mammals SN: Branch of zoology concerned with the study of mammals. TNR: 685 mammals BT: vertebrates NT: bears bats RT: mammalogy SN: Vertebrate animals, generally large, with skin covered by hair and large brain cavities. Females have mammary glands for feeding the young, who are usually born quite mature. TNR: 686 managed fires USE: controlled fires managed flooding USE: controlled flooding management methods BT: methods NT: decision support methods environmental assessment hazard preparedness information management methods natural resource management risk assessment SN: Techniques of judiciously controlling or directing resources for a predetermined goal. TNR: 689 manganese BT: chemical elements RT: metal elements UF: Mn SN: Metal element with symbol Mn and atomic number 25 TNR: 1499 mangroves USE: aquatic vegetation mantle (earth) BT: earth structure NT: asthenosphere RT: geophysics lithosphere SN: Zone of earth's interior between the crust and the core. It is 2,900 kilometers (1,740 miles) thick and consists of a dense upper layer (upper mantle) and a partially molten lower layer (lower mantle), separated by a transition zone. TNR: 690 manuals BT: reports UF: technical instructions user guides SN: Documents giving instructions on using specified equipment or accomplishing specified tasks. TNR: 691 map coordinate systems BT: topics RT: cartography geographic information systems (GIS) geography UF: coordinate systems geographic coordinate systems grid coordinate systems horizontal datums map projections vertical datums SN: Systems using sets of numbers combined with geometric nets or grids to specific positions on a map or globe. TNR: 692 mapmaking USE: cartography map making USE: cartography mapping USE: cartography mapping centers (USGS) USE: USGS mapping centers map projections USE: map coordinate systems maps USE: maps and atlases map sales (USGS) USE: USGS sales and distribution services maps and atlases BT: product types RT: cartography UF: cadastral maps earthquake activity maps ground motion maps seismic hazard maps shaking maps (seismic) earthquake epicenter maps engineering geology maps geotechnical properties maps rock mechanics maps subsurface maps geophysical maps land subsidence maps slope stability maps aeromagnetic maps atlases basement maps depth-to maps earthquake occurrence maps geochemical anomaly maps geologic maps gravity anomaly maps hydrologic maps land use maps landslide maps landslide susceptibility maps lithologic maps magnetic anomaly maps maps paleotectonic maps quadrangle maps relief maps seismic reflection survey maps species distribution maps surficial geologic maps tectonic maps thickness maps charts topographic maps seismicity maps SN: Representation, usually on a flat surface, of a part or whole of the Earth or other parts of the universe. Collections of maps linked digitally or bound together in a book are called atlases. TNR: 700 map servers (USGS) USE: USGS map servers maps on demand (USGS) USE: USGS maps on demand marine biology BT: life sciences RT: aquatic biology aquatic ecosystems benthic ecosystems commercial fishery resources fishery resources marine ecosystems marine fishery resources migratory species ocean sciences recreational fishery resources reef ecosystems whaling UF: biological oceanography SN: Branch of biology concerned with the organisms and habitats of the seas and oceans. TNR: 702 marine chemistry BT: water chemistry RT: CTD measurement marine water quality ocean characteristics ocean salinity ocean sciences UF: chemical oceanography ocean chemistry water properties (marine) SN: Branch of chemistry that deals with the properties, composition, structure, and interaction of substances in the seas and oceans. TNR: 703 marine ecosystems BT: aquatic ecosystems NT: reef ecosystems RT: aquatic biology ecology marine biology SN: Biological communities composed of plants and animals living primarily in or on seawater. TNR: 704 marine fishery resources BT: fishery resources NT: whaling RT: aquatic biology commercial fishery resources ichthyology marine biology reef ecosystems UF: coastal fisheries coastal fishing deep sea fisheries deep sea fishing reef fisheries reef fishing SN: The stock of fisheries located in seas and oceans. TNR: 705 marine geology BT: geology RT: marine geophysics ocean sciences sea-floor characteristics side-scan sonar methods UF: geological oceanography SN: Branch of geology concerned with the composition, geologic history, and earth processes of the ocean floor and the continental margin. TNR: 706 marine geophysics BT: geophysics RT: marine geology ocean characteristics ocean processes ocean sciences side-scan sonar methods SN: Branch of earth sciences concerned with the physical processes of the oceans and continental margins. TNR: 707 marine water quality BT: water quality RT: hydrology marine chemistry ocean sciences UF: ocean water quality SN: Observed intrinsic characteristics of marine waters affecting their ability to support life or facilitate biological processes such as waste decomposition. TNR: 708 marsh ecosystems USE: wetland ecosystems marshland ecosystems USE: wetland ecosystems mass spectrometry USE: mass spectroscopy mass spectroscopy BT: chemical analysis RT: biochemistry geochemistry UF: mass spectrometry SN: Instrumental technique to separate and identify molecules. Gaseous ions are formed, with or without fragmentation. Their mass/charge ratios and relative electrical abundance are then measured or the spectra are recorded. TNR: 711 mass wasting BT: geologic processes NT: landslides UF: slumps creep SN: The down slope movement of earth material under the influence of gravity. TNR: 1736 materials standards BT: product types UF: laboratory reference materials standard reference samples SN: Physical materials such as chemicals, rocks, water, or biological materials that are used for reference when carrying out laboratory analysis. TNR: 1729 mathematical methods USE: computational methods mathematical modeling BT: computational methods NT: mathematical simulation RT: spatial analysis UF: fractal geometric methods groundwater flow modeling modeling (mathematical) numerical methods streamflow modeling SN: Creating mathematical expressions to represent a simplified view of real-world systems. TNR: 713 mathematical simulation BT: mathematical modeling SN: A computer algorithm or model, which was created to represent a simplified version of a real world situation. TNR: 715 Md USE: mendelevium media relations (USGS) USE: USGS media relations meetings (USGS) USE: USGS meetings meitnerium BT: chemical elements RT: metal elements UF: Mt SN: Metal element with symbol Mt and atomic number 109 TNR: 1501 memos USE: reports mendelevium BT: chemical elements RT: actinide series elements UF: Md SN: Rare earth (actinide series) element with symbol Md and atomic number 101 TNR: 1502 mercury BT: chemical elements RT: metal elements UF: Hg SN: Metal element with symbol Hg and atomic number 80 TNR: 1503 mercury contamination BT: toxic trace element contamination RT: biochemistry ecology ecotoxicology SN: Biological disturbances caused by mercury compounds that have entered the environment. TNR: 720 meristics BT: laboratory methods RT: morphology (biological) systematics and taxonomy UF: morphometrics SN: Branch of zoology concerned with classifying animals by counting and measuring body parts. TNR: 721 mesozoic BT: phanerozoic NT: cretaceous jurassic triassic TNR: 1640 metadata USE: catalogs and indexes metadata development BT: information system design and development RT: information sciences SN: Use for the development of metadata schemes and applications. Do not use for general cases where metadata are part of the activities. TNR: 723 metal elements BT: chemical element groups RT: scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium hafnium tantalum tungsten rhenium osmium irridium platinum gold mercury rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium ununnilium ununnunium ununnubium aluminum gallium germanium indium tin antimony thallium lead bismuth polonium TNR: 1504 metallic ores BT: mineral resources NT: gold ores RT: economic geology mineralogy nonmetallic mineral resources UF: ore deposits (metallic) SN: Resources from which ductile, malleable, opaque,and reflective metals that are also good heat and electricity conductors can be extracted. TNR: 724 metallogeny USE: ore formation metamorphic rocks BT: rocks and deposits RT: metamorphism (geological) petrology SN: Sedimentary or igneous rocks which have undergone such intense changes in temperature, pressure, structural stress, or chemical environment that they are transformed into denser rocks. TNR: 725 metamorphism (biological) USE: metamorphosis metamorphism (geological) BT: geologic processes RT: geochemistry geology geophysics metamorphic rocks SN: Process by which rocks are altered in composition and texture by extreme heat, high pressure, or the action of chemicals. TNR: 727 metamorphosis BT: organism growth and development UF: metamorphism (biological) SN: Transformation in animals, such as amphibians and insects, from one developmental stage to another. TNR: 726 meteor impact USE: impact cratering meteorites BT: planetary bodies RT: rocks and deposits UF: chondrites bolides meteors SN: Masses of rock or metal from space that reach the earth's surface without burning up. Use for 'meteors' or 'meteoroids' as well as 'meteorites'. USGS is more likely to have information about 'meteorites' since these are objects found on the earth. TNR: 730 meteorology BT: atmospheric sciences RT: atmospheric and climatic processes climatology hurricanes hydrology ocean currents ocean sciences planetary sciences storms tornadoes SN: Branch of science dealing with the short-term variations of atmospheric conditions including wind, precipitation, temperature, humidity, cloud cover, and air pressure. TNR: 731 meteors USE: meteorites methane hydrate resources USE: gas hydrate resources methane resources (coalbed) USE: coalbed methane resources methods BT: Categories NT: computational methods field methods laboratory methods management methods photography remote sensing videography SN: Techniques, methods, procedures, or strategies for research, management, collection, or analysis of scientific information in USGS. TNR: 734 Mg USE: magnesium microbes BT: organism groupings (non-taxonomic) UF: microorganisms SN: Microscopic, typically one-celled organisms. TNR: 1707 microbiology BT: life sciences NT: bacteriology virology RT: archaea bacteria culturing (specimens) faunal and floral census (microscopic) plankton producers (organisms) protists SN: Branch of biology dealing with organisms too small to be seen without the use of a microscope. TNR: 735 microclimate USE: atmospheric and climatic processes microfossils USE: fossils microorganisms USE: microbes micropaleontology BT: paleontology RT: calcareous nannoplankton conodonts diatoms dinoflagellates faunal and floral census (microscopic) fossils protists SN: Branch of paleontology dealing with fossils too small to be seen without a microscope. TNR: 738 microscope methods USE: microscopy microscopy BT: laboratory methods NT: electron microscopy optical microscopy RT: faunal and floral census (microscopic) UF: microscope methods SN: Laboratory methods using instruments that employ optical lenses or radiation to study objects too small to be seen by the naked eye. TNR: 740 microtomy BT: optical microscopy SN: Laboratory methods using special instruments, or microtomes, to cut very thin slices of specimens for microscopic studies. TNR: 741 microwave imaging BT: remote sensing NT: SMMR SSM/I RT: geography radar imaging SN: Remote sensing method using short high frequency electromagnetic waves reflected or radiated from the ground. TNR: 742 migration (organisms) BT: ecological processes RT: animal behavior biogeography dispersal (organisms) ecology life sciences migratory species UF: biological invasions flyways seasonal migration SN: The movement of animals, often periodical, from one area to another due to seasonal changes, availability of food, or climatic conditions. TNR: 743 migratory species BT: organism groupings (non-taxonomic) RT: animal behavior aquatic biology biogeography ecology marine biology migration (organisms) zoology UF: anadromous fish diadromous fish SN: Species that have a pattern of moving from one geographical area to another, primarily according to the seasons, and usually traveling long distances along established routes. TNR: 744 mine drainage BT: industrial pollution RT: mining hazards SN: Introduction of harmful substances into the environment from mines and tailings. TNR: 1724 mineralogical analysis USE: chemical analysis mineralogy BT: geology RT: gem resources gold ores metallic ores mineral resources x-ray diffraction UF: crystallography gemology SN: Branch of earth sciences concerned with the study of naturally occurring inorganic elements or compounds. TNR: 747 mineral resources BT: natural resources NT: metallic ores nonmetallic mineral resources RT: economic geology mineralogy UF: industrial minerals minerals SN: Natural occurrences of useful inorganic elements or compounds. TNR: 745 minerals USE: mineral resources mining and quarrying BT: natural resource extraction UF: quarrying SN: Extracting mineral deposits from a pit, tunnel, or excavation. TNR: 749 mining hazards BT: human impacts RT: engineering sciences hazards social sciences waste treatment and disposal mine drainage SN: Dangerous conditions which result from the extraction of naturally occurring mineral deposits. Includes tunnel collapses, fires, and explosions. TNR: 750 mining water use BT: offstream water use RT: hydraulic engineering hydrology SN: Water use for the extraction of naturally occurring mineral deposits by mining or quarrying. TNR: 751 miocene BT: neogene TNR: 1641 mississippian BT: paleozoic UF: lower carboniferous TNR: 1642 mites USE: arachnids mitigation USE: remediation mixed forest ecosystems USE: forest ecosystems mixed grass ecosystems USE: grassland ecosystems Mn USE: manganese Mo USE: molybdenum modeling (mathematical) USE: mathematical modeling molecular biology BT: life sciences RT: cell biology genetics organism growth and development SN: Branch of biology concerned with the study of physiology at the molecular level. TNR: 756 molluscs USE: mollusks mollusks BT: invertebrates RT: invertebrate zoology shellfish UF: molluscs SN: Invertebrates belonging to the phylum Mollusca with soft, nonsegmented bodies, often covered by a hard shell. Includes snails, clams, oysters, whelks, mussels, slugs, octopuses, and squids. TNR: 757 molybdenum BT: chemical elements RT: metal elements UF: Mo SN: Metal element with symbol Mo and atomic number 42 TNR: 1509 morphology (biological) BT: life sciences RT: meristics SN: The scientific study of the form, shape, and structure of plants and animals and their fossil remains. TNR: 758 morphometrics USE: meristics mosses BT: nonvascular plants RT: botany liverworts and hornworts SN: Simple green land plants, member of the phyla Bryophyta, along with liverworts and hornworts. They have leaves and a stem, but always lack roots. TNR: 760 moths USE: butterflies and moths Mt USE: meitnerium mudflows USE: landslides multispectral imaging BT: remote sensing RT: geography UF: Landsat images thematic mapper SN: A method of remote sensing that obtains optical representations in two or more ranges of frequencies or wave lengths. TNR: 765 multivariate statistical analysis BT: statistical analysis SN: Statistical study using a number of independent variables or measurements of the same attribute. TNR: 766 mutualism USE: symbiosis mycology BT: life sciences RT: botany fungi lichens SN: Branch of biology concerned with the study of fungi. TNR: 767 N USE: nitrogen Na USE: sodium native species BT: organism groupings (non-taxonomic) NT: endemic species RT: biodiversity ecology life sciences nonindigenous species UF: indigenous species SN: Organisms originating in the area where they live. TNR: 768 natural attenuation (harmful chemicals) USE: biodegradation natural contaminants USE: contamination and pollution natural gas resources BT: energy resources NT: coalbed methane resources gas hydrate resources RT: economic geology UF: petroleum resources (gas) SN: Stocks of naturally formed hydrocarbon gases which are usually associated with petroleum fields. Useful for heating, they are principally methane, but can be ethane, butane, or propane. TNR: 770 natural remanent magnetism USE: remanent magnetism natural remanent magnetization analysis BT: paleomagnetic analysis RT: geophysics UF: natural remnant magnetization analysis SN: Method which measures the intensity and direction of residual magnetism in rocks to determine their age and history. TNR: 771 natural remnant magnetization analysis USE: natural remanent magnetization analysis natural resource assessment BT: natural resource management UF: resource assessment SN: Estimation of the actual or potential value of natural materials and processes. TNR: 773 natural resource exploration BT: topics UF: dowsing exploration seismology exploration prospecting seismic exploration SN: Techniques for locating deposits or stocks of useful minerals, water, and other resources using reconnaissance or instrumental methods. TNR: 774 natural resource extraction BT: topics NT: mining and quarrying well drilling placer deposit mining UF: resource extraction SN: Removal of natural materials or properties (such as heat) for use. TNR: 775 natural resource management BT: management methods NT: biological population management controlled flooding ecosystem management natural resource assessment remediation water resource management watershed management fire control RT: ecosystem monitoring natural resources population and community ecology UF: conservation environmental management environmental planning resource conservation resource restoration SN: Using a combination of techniques to control or direct the use of resources and limit population size to reach a predetermined goal, such as sustainability. TNR: 776 natural resources BT: topics NT: mineral resources energy resources soil resources fishery resources forest resources water resources RT: earth sciences life sciences natural resource management SN: Stocks of anything naturally occurring that have a beneficial use for man including economic, nutritional, recreational, aesthetic, and other benefits. TNR: 777 navigating USE: geolocation measurement Nb USE: niobium Nd USE: neodymium Ne USE: neon nekton BT: organism groupings (non-taxonomic) SN: Free-swimming aquatic organisms able to move without depending on waves, currents, and tides. TNR: 779 nematodes USE: roundworms neodymium BT: chemical elements RT: lanthanide series elements UF: Nd SN: Rare earth (lanthanide series) element with symbol Nd and atomic number 60 TNR: 1516 neogene BT: tertiary NT: miocene pliocene TNR: 1643 neon BT: chemical elements RT: noble gas elements UF: Ne SN: Noble gas element with symbol Ne and atomic number 10 TNR: 1517 Neoproterozoic BT: proterozoic NT: Ediacaran SN: The latest geologic era of the Proterozoic Eon. TNR: 1734 neotectonic processes BT: tectonic processes RT: earthquake probabilities structural geology tectonophysics UF: neotectonics SN: Changes which took place during geological time after the Miocene era and are associated with the structural forces that affect the deformation, uplift, and movement occurring in the earth's crust. TNR: 781 neotectonics USE: neotectonic processes neptunium BT: chemical elements RT: actinide series elements UF: Np SN: Rare earth (actinide series) element with symbol Np and atomic number 93 TNR: 1518 neutron activation analysis BT: chemical analysis RT: biochemistry geochemistry SN: Sensitive laboratory technique for both qualitative and quantitative analysis of elements in samples. Target nuclei are bombarded with neutron beams to start nuclear reactions which emit characteristic gamma ray radiations. TNR: 783 new mapping projects (USGS) USE: USGS news new projects (USGS) USE: USGS news news (USGS) USE: USGS news newsletters USE: reports news releases BT: official communications UF: press releases SN: Short information memoranda issued by organizations to highlight new activities, appointments, or discoveries for the news media. TNR: 787 Ni USE: nickel nickel BT: chemical elements RT: metal elements UF: Ni SN: Metal element with symbol Ni and atomic number 28 TNR: 1520 niobium BT: chemical elements RT: metal elements UF: Nb columbium SN: Metal element with symbol Nb and atomic number 41 TNR: 1521 nitrogen BT: chemical elements RT: nonmetal elements UF: N SN: Nonmetal element with symbol N and atomic number 7 TNR: 1522 nitrogen content USE: nutrient content (water) No USE: nobelium nobelium BT: chemical elements RT: actinide series elements UF: No SN: Rare earth (actinide series) element with symbol No and atomic number 102 TNR: 1524 noble gas elements BT: chemical element groups RT: helium neon argon krypton xenon radon UF: inert gases TNR: 1525 non-formal education (USGS) USE: USGS lifelong learning programs non-indigenous species USE: nonindigenous species non-native species USE: nonindigenous species non-vascular plants USE: nonvascular plants nonindigenous species BT: organism groupings (non-taxonomic) NT: invasive species RT: biodiversity ecology life sciences native species UF: alien species exotic species foreign species introduced species non-indigenous species non-native species SN: Organisms accidentally or intentionally introduced into areas where they did not previously originate or live. TNR: 797 nonmetal elements BT: chemical element groups RT: boron carbon nitrogen oxygen silicon phosphorus sulfur arsenic selenium tellurium TNR: 1526 nonmetallic mineral resources BT: mineral resources NT: building stone resources gem resources RT: clay deposits economic geology gravel deposits metallic ores sand deposits UF: ore deposits (non-metallic) SN: Useful mineral deposits that are not metals. Includes materials used for construction, decoration, fuel, and other purposes. TNR: 798 nonpoint-source pollution BT: contamination and pollution SN: Contamination of the environment from sources spread widely across an area, not from a small number of identifiable locations. TNR: 1363 nonvascular plants BT: plants (organisms) NT: liverworts and hornworts mosses RT: botany UF: non-vascular plants SN: Simple plants which lack conducting tissues known as vascular bundles, a group of specialized cells made up of xylem and phloem. TNR: 801 normalized burn ratio US+: fire damage remote sensing Np USE: neptunium nuclear magnetic resonance spectroscopy USE: chemical analysis nuclear reactors (USGS) USE: USGS nuclear reactors nuclear waste repositories USE: waste treatment and disposal nuisance species BT: organism groupings (non-taxonomic) SN: Organisms whose presence or behavior has undesirable effects on human activities. TNR: 1728 numerical methods USE: mathematical modeling nutrient balance USE: nutrient cycling nutrient content (water) BT: water properties RT: hydrology nutrient cycling water chemistry UF: nitrogen content phosphorus content SN: Contaminants in water that nourish organisms, especially plants. Includes nitrogen and phosphorus, either of which can lead to the harmful growth of algae and other plants when present to excess in a body of water. TNR: 806 nutrient cycling BT: biogeochemical cycling NT: food web RT: biochemistry ecology nutrient content (water) UF: nutrient balance SN: The exchange of elements or compounds essential for the nourishment of organisms in an ecosystem. TNR: 807 nutrition USE: health and disease O USE: oxygen observatories (USGS) USE: USGS observatories ocean-atmosphere interaction BT: atmospheric and climatic processes RT: atmospheric sciences ocean processes ocean sciences UF: El Nino La Nina SN: Processes, including momentum, heat, gas and other exchanges, which result in profound effects on climate and interactions between the air in the lowest part of the atmosphere and the oceans. TNR: 823 ocean bottom characteristics USE: sea-floor characteristics ocean characteristics BT: earth characteristics NT: ocean salinity ocean temperature sea-floor characteristics sea-level change RT: marine chemistry marine geophysics ocean processes ocean sciences oceanic lithosphere surface water (non-marine) water resources sea ice concentration UF: ocean monitoring oceans SN: The attributes and process of seas and oceans. TNR: 810 ocean chemistry USE: marine chemistry ocean circulation BT: ocean processes RT: climatology ocean currents ocean sciences tides (oceanic) water circulation UF: circulation (ocean) SN: Movement of large masses of water within an ocean. TNR: 812 ocean current measurement US+: field inventory and monitoring ocean currents ocean currents BT: ocean processes RT: meteorology ocean circulation ocean sciences tides (oceanic) UF: ocean current measurement SN: Recurrent strong flows of seawater generated by wind or variations in water density along a given path. TNR: 814 oceanic lithosphere BT: lithosphere RT: ocean characteristics sea-floor characteristics tectonophysics SN: The solid outer zone of the earth, covered by seawater, and comprised of the crust and the upper layer of the mantle. TNR: 824 ocean monitoring US+: field inventory and monitoring ocean characteristics oceanography USE: ocean sciences ocean processes BT: biological and physical processes NT: ocean circulation ocean currents ocean waves tides (oceanic) RT: marine geophysics ocean characteristics ocean sciences ocean-atmosphere interaction surface water (non-marine) UF: oceans SN: Recurrent natural changes that are physical, biological, or chemical, actively affecting the seas and oceans. TNR: 816 oceans US+: ocean processes ocean characteristics ocean salinity BT: ocean characteristics RT: marine chemistry ocean sciences salinity SN: Measure of the percentage of dissolved salts in seawater. TNR: 817 ocean sciences BT: earth sciences NT: paleoceanography RT: bathymetry CTD measurement global change global warming hydrology marine biology marine chemistry marine geology marine geophysics marine water quality meteorology ocean characteristics ocean circulation ocean currents ocean processes ocean salinity ocean temperature ocean waves ocean-atmosphere interaction sea-floor characteristics sea-level change tides (oceanic) tsunamis underwater photography UF: oceanography physical oceanography SN: Sciences involved in the study of geological, biological, chemical, and physical characteristics and processes of the oceans. TNR: 818 ocean temperature BT: ocean characteristics NT: sea surface temperature RT: atmospheric sciences ocean sciences UF: temperature (ocean) SN: Distribution of heat in the oceans, including surface water, thermocline and mode waters, and deep waters. Includes discussion and measures of both in-situ and potential temperature. TNR: 819 ocean tides USE: tides (oceanic) ocean water quality USE: marine water quality ocean wave measurement US+: ocean waves field inventory and monitoring ocean waves BT: ocean processes NT: tsunamis RT: ocean sciences UF: ocean wave measurement water waves SN: A periodic movement of seawater caused by wind, tide, and currents. TNR: 822 off-stream water use USE: offstream water use official communications BT: product types NT: news releases policies and regulations speeches and testimony SN: Corporate releases of information by USGS not generally intended to document the details of scientific data or techniques for a scientific audience. TNR: 1349 offstream water use BT: water use NT: agricultural water use commercial water use domestic water use industrial water use mining water use RT: hydraulic engineering hydrology UF: off-stream water use SN: Water withdrawn or diverted from a ground- or surface-water source for public-water supply, industry, irrigation, livestock, thermoelectric power generation and other uses. Sometimes called off-channel use or withdrawal. TNR: 828 oil resources BT: energy resources NT: oil sand resources oil shale resources RT: economic geology UF: petroleum resources (oil) SN: Deposits (pools) of highly valuable liquid hydrocarbons or fossil fuels. TNR: 829 oil sand resources BT: oil resources RT: economic geology UF: tar sand resources SN: Deposits of sandstone or unconsolidated sand containing bitumen that can be extracted as an oil resource. TNR: 830 oil shale resources BT: oil resources RT: economic geology SN: Deposits of finely grained sedimentary rock containing kerogen that can be distilled to produce liquid or gaseous hydrocarbons. TNR: 831 oligocene BT: paleogene TNR: 1644 omnivores BT: consumers (organisms) RT: ecology zoology SN: Animals that eat both plant and animal materials. TNR: 832 ontogeny USE: organism growth and development open houses (USGS) USE: USGS open houses optical backscatterance sensing USE: optical methods optically-stimulated luminescence dating USE: luminescence dating optical methods BT: field inventory and monitoring UF: optical backscatterance sensing optical reflectance measurement SN: Measurement of light transmission or reflectance in the field to estimate, for example, the density of suspended sediment in water bodies. TNR: 1672 optical microscopy BT: microscopy NT: microtomy RT: petrography SN: Scientific techniques using a microscope with one or more lenses illuminated with visible light to view small objects. TNR: 835 optical reflectance measurement USE: optical methods oral presentations USE: speeches and testimony ordering services (USGS) USE: USGS sales and distribution services ordovician BT: paleozoic TNR: 1645 ore deposits (metallic) USE: metallic ores ore deposits (non-metallic) USE: nonmetallic mineral resources ore formation BT: geochemical processes UF: metallogeny SN: Geochemical processes resulting in concentration of useful chemical elements and compounds, in earth materials. Typically refers to metal ores. TNR: 1703 organic decomposition USE: biogeochemical cycling organism groupings (non-taxonomic) BT: topics NT: biota consumers (organisms) decomposers endangered species game species keystone species macroinvertebrates migratory species native species nekton nonindigenous species plankton pollinators producers (organisms) shellfish vegetation wildlife benthos microbes parasites nuisance species RT: life sciences organisms SN: Used for categories of living organisms that are not taxonomic and that include species from more than one taxonomic group. TNR: 841 organism growth and development BT: physiological processes NT: metamorphosis RT: developmental biology molecular biology UF: ontogeny SN: Changes that living things undergo as they progress from inception as a single cell to adult forms. TNR: 842 organisms BT: topics NT: algae animals archaea bacteria fungi lichens plants (organisms) protists viruses RT: life sciences organism groupings (non-taxonomic) UF: biological organisms SN: Living individuals that grow, reproduce, and die. TNR: 843 orienteering USE: geolocation measurement ornithology BT: vertebrate zoology RT: birds pollinators SN: Branch of biology concerned with the study of birds. TNR: 845 orthoimagery US+: image collections aerial photography orthophotographs US+: image collections aerial photography Os USE: osmium osmium BT: chemical elements RT: metal elements UF: Os SN: Metal element with symbol Os and atomic number 76 TNR: 1530 osmosis BT: physiological processes SN: Transfer of substances through biological membranes. TNR: 1364 ostracodes BT: crustaceans RT: invertebrate zoology SN: Small aquatic crustaceans belonging to the subclass Ostracoda, characterized by a bivalve shell. TNR: 848 outer core (earth) BT: core (earth) RT: geophysics SN: Outer zone of the earth's core between the mantle and the inner core. TNR: 849 outfall USE: contamination and pollution over-fishing USE: overfishing over-grazing USE: overgrazing overfishing BT: human impacts RT: fishery resources ichthyology social sciences wildlife biology UF: over-fishing SN: Taking too many fish from an area beyond the capacity for the population to replenish its numbers. The balance of the ecosystem is upset, leading to long-term depletion of fish stock. TNR: 852 overgrazing BT: human impacts UF: over-grazing SN: The practice of allowing animals to eat vegetation, especially ground cover, beyond the capacity of the plant population to replenish itself. Leads to erosion and other harm to the ecosystem. TNR: 853 oxidation and reduction BT: geochemical processes UF: fermentation SN: Addition or reduction of oxygen in a compound accompanied by exchange of electrons among atoms. TNR: 1708 oxygen BT: chemical elements RT: nonmetal elements UF: O SN: Nonmetal element with symbol O and atomic number 8 TNR: 1531 oxygen content (water) BT: water properties RT: eutrophication hydrology water chemistry UF: anoxia dissolved oxygen hypoxia SN: Measurement of the concentration of oxygen dissolved in water, which is an important indicator of the condition of a water body. TNR: 854 oxygen isotope analysis BT: light stable isotope analysis RT: biochemistry geochemistry SN: Experimental determination of the proportion of a given stable oxygen isotope in a sample. TNR: 855 ozone layer BT: atmospheric composition RT: atmospheric sciences greenhouse gases UF: ozonesphere SN: Upper atmosphere layer composed of ozone, a gas made up of molecules comprised of three oxygen atoms, which helps to shield the earth from ultraviolet rays. TNR: 856 ozonesphere USE: ozone layer P USE: phosphorus Pa USE: protactinium palaeozoic USE: paleozoic paleobotany BT: paleontology RT: botany palynology SN: Branch of paleontology concerned with the study of fossil plants and plant life in the geologic past. TNR: 858 paleoceanography BT: ocean sciences RT: paleontology SN: Study of the oceans in the geologic past, including their physical, chemical, biologic, and geologic history. TNR: 859 paleocene BT: paleogene TNR: 1647 paleoclimate USE: climate change paleogene BT: tertiary NT: eocene oligocene paleocene TNR: 1648 paleogeography BT: geography SN: Study of the history of earth surface characteristics; geomorphology in the past. TNR: 1679 paleomagnetic analysis BT: laboratory methods NT: Curie temperature analysis laboratory-induced magnetization analysis magnetic hysteresis analysis magnetic susceptibility analysis natural remanent magnetization analysis RT: geophysics SN: Determination of the intensity and direction of residual magnetism in rocks to study changes in the earth's magnetic field during past geologic time. TNR: 860 paleontology BT: earth sciences NT: invertebrate paleontology micropaleontology paleobotany vertebrate paleontology RT: biostratigraphy fossils geologic history ichnofossils life sciences paleoceanography UF: paleozoology phylogeny taphonomy SN: Study of life in past geologic time based on fossil plants and animals. TNR: 861 paleoseismology BT: seismology RT: geologic history SN: Branch of seismology concerned with ancient earthquakes. Clues which indicate seismic activities in the geologic past are used to date and determine the effects of those earthquakes. TNR: 862 paleotectonic maps US+: maps and atlases tectonic processes paleozoic BT: phanerozoic NT: cambrian devonian mississippian ordovician pennsylvanian permian silurian UF: palaeozoic TNR: 1649 paleozoology USE: paleontology palladium BT: chemical elements RT: metal elements UF: Pd SN: Metal element with symbol Pd and atomic number 46 TNR: 1534 palynology BT: botany RT: paleobotany plants (organisms) SN: Branch of botany concerned with the study of pollen and spores, especially fossil remains. These are used to study plant life and dispersal in geologic history and to date deposits. TNR: 865 pamphlets, brochures, and booklets USE: reports panchromatic imaging BT: remote sensing RT: geography SN: Photographic technique which uses emulsions, films, or plates sensitive to all colors in light to produce black-and-white photographs. Often used in aerial and satellite photography. TNR: 867 papers (publications) USE: reports parasites BT: organism groupings (non-taxonomic) SN: Symbiotic organisms that are detrimental to the host. TNR: 1709 parasitism USE: symbiosis parasitology BT: life sciences RT: health and disease wildlife biology SN: Branch of biology concerned with the study of organisms that, living on or in another organism, take nutrition from the host and often harm it. TNR: 871 particle-beam spectroscopy BT: chemical analysis RT: biochemistry geochemistry SN: Analytical technique using a concentrated beam of charged subatomic particles. TNR: 872 particle-size analysis USE: grain-size analysis partnerships (USGS) USE: USGS partnerships pathobiology USE: pathology pathology BT: life sciences RT: health and disease plant and animal testing therapeutic methods UF: pathobiology SN: Branch of biology concerned with the study of the causes, progress, symptoms, diagnosis, and effects of diseases. TNR: 876 Pb USE: lead PCBs USE: industrial pollution Pd USE: palladium pedogenesis USE: soil formation pedology (soils) USE: soil sciences pennsylvanian BT: paleozoic UF: upper carboniferous TNR: 1650 percolation BT: hydrologic processes RT: permeability UF: infiltration (water) SN: The movement of water through fractures or interstices of a rock or soil. TNR: 1365 periphyton BT: vegetation RT: algae SN: A plant assemblage including microbial communities of algae and cyanobacteria living attached to submerged aquatic vegetation. TNR: 1366 permafrost BT: rocks and deposits SN: Rocks and deposits in which the interstitial waters remain perennially frozen. TNR: 1370 permeability BT: earth material properties RT: percolation UF: soil permeability SN: The ability of fluids to pass through an earth material, typically depending on the connectedness of pore space in the material. TNR: 1368 permian BT: paleozoic TNR: 1651 personnel (USGS) USE: USGS personnel pest control BT: biological population management SN: Intentional reduction in the abundance of specific harmful organisms in a given area. TNR: 1685 pesticide and herbicide contamination BT: contamination and pollution RT: biochemistry ecology ecotoxicology UF: biocide contamination degradation products (chemical) herbicide contamination insecticide contamination SN: Pollution resulting from chemical agents applied to crops, rights of way, lawns, or residences to control weeds, insects, fungi, nematodes, rodents or other pests (pesticides) or kill undesirable plants (herbicides). TNR: 879 petrography BT: laboratory methods RT: optical microscopy petrology rocks and deposits UF: thin section analysis SN: Use of optical microscopy for the description and classification of rocks. TNR: 880 petroleum resources (gas) USE: natural gas resources petroleum resources (oil) USE: oil resources petrology BT: geology RT: diagenesis igneous rocks metamorphic rocks petrography rocks and deposits sedimentary rocks SN: Branch of earth sciences concerned with the origin, structure, alteration, and composition of rocks. TNR: 883 pH (water) USE: water pH phanerozoic BT: geologic time periods NT: cenozoic mesozoic paleozoic TNR: 1652 pharmaceutical contamination BT: contamination and pollution SN: Unintentional release of pharmaceutical compounds into the environment; work focuses on the effects of these compounds on organisms and water resources. TNR: 1693 phosphorus BT: chemical elements RT: nonmetal elements UF: P SN: Nonmetal element with symbol P and atomic number 15 TNR: 1537 phosphorus content USE: nutrient content (water) photo galleries (USGS) USE: USGS exhibits and facility tours photogrammetry USE: remote sensing photographs US+: photography image collections photography BT: methods NT: aerial photography underwater photography RT: videography UF: photographs SN: Process of using chemical reactions on sensitized emulsions, films or plates exposed to light (or other forms of radiant energy) to produce images or representations of objects. TNR: 889 photosynthesis BT: physiological processes SN: Conversion of sunlight, water, and nutrients into energy by plants. TNR: 1371 phycology BT: botany RT: algae algal blooms calcareous nannoplankton diatoms dinoflagellates lichens plankton UF: algology SN: Branch of biology concerned with the study of algae. TNR: 890 phylogeny USE: paleontology physical oceanography USE: ocean sciences physiography USE: land surface characteristics physiological processes BT: biological and physical processes NT: osmosis photosynthesis organism growth and development bioluminescence SN: Characteristics and processes of individual organisms that are not the direct result of their interaction with other organisms or with the environment. TNR: 1347 physiology USE: anatomy and physiology phytoplankton BT: plankton RT: calcareous nannoplankton SN: Small, mostly microscopic aquatic plants such as algae and bacteria suspended in water. TNR: 1372 pictures USE: image collections placer deposit mining BT: natural resource extraction SN: Extraction of minerals, typically metal ores, from unconsolidated surficial materials such as stream sediments. TNR: 1373 plains ecosystems USE: grassland ecosystems planetary bodies BT: topics NT: meteorites RT: planetary sciences impact cratering SN: Large celestial masses of rock, metal, or gas orbiting around a star. Use for extraterrestrial bodies. TNR: 900 planetary sciences BT: sciences RT: meteorology planetary bodies scientific careers UF: astronomy planetology SN: Scientific study of the solid bodies of the solar system, including planets, moons, asteroids, meteorites, and interplanetary materials. TNR: 901 planetology USE: planetary sciences plankton BT: organism groupings (non-taxonomic) NT: phytoplankton RT: aquatic biology calcareous nannoplankton microbiology phycology UF: planktonic ecosystems zooplankton SN: Floating aquatic plants (phytoplankton) and animals (zooplankton) which are often microscopic and drift with the current in lakes, rivers, and oceans. TNR: 903 planktonic ecosystems US+: plankton aquatic ecosystems planning reports USE: reports plant and animal tagging BT: field sampling RT: life sciences UF: animal tagging banding bird banding radioisotope tagging tagging SN: Methods of attaching a tag or marker to an organism as long-term identification for study purposes. TNR: 906 plant and animal testing BT: laboratory methods RT: anatomy and physiology ecotoxicology pathology UF: animal testing SN: Use of live or dead organisms for scientific study. TNR: 907 plant distribution USE: biogeography plants (organisms) BT: organisms NT: nonvascular plants vascular plants RT: botany palynology vegetation UF: flora SN: Organisms which belong to the plant kingdom. Commonly multicellular, they produce food through photosynthesis. TNR: 909 plate tectonics USE: tectonic processes platinum BT: chemical elements RT: metal elements UF: Pt SN: Metal element with symbol Pt and atomic number 78 TNR: 1538 pleistocene BT: quaternary UF: ice age TNR: 1653 pliocene BT: neogene TNR: 1654 plot sampling BT: field sampling RT: ecology transect sampling trenching SN: Outlining small areas of land within a larger area to use as samples to study biological populations or ecosystems. TNR: 911 Plutonic rocks BT: igneous rocks UF: intrusive rocks magma SN: Rocks formed at considerable depth by crystallization of magma and/or by chemical alteration. They are characteristically medium- to coarse-grained, of granitoid texture. TNR: 1341 plutonium BT: chemical elements RT: actinide series elements UF: Pu SN: Rare earth (actinide series) element with symbol Pu and atomic number 94 TNR: 1539 Pm USE: prometium Po USE: polonium podcasts USE: sound recordings polar bears USE: bears policies (USGS) USE: USGS policies and regulations policies and regulations BT: official communications RT: reports USGS policies and regulations UF: regulations SN: Rules, orders, and procedures issued by organizations or governments for administrative, controlling, and managing purposes. TNR: 913 political boundaries USE: administrative and political boundaries pollen analysis USE: faunal and floral census (microscopic) pollination BT: ecological processes RT: pollinators SN: Wind, bees, or other agents transfer plant pollen from flower anthers or cones to stigmas, thereby fertilizing plants for reproduction. TNR: 915 pollinators BT: organism groupings (non-taxonomic) RT: ecology entomology ornithology pollination zoology SN: Organisms that aid in the growth and distribution of plants by transferring pollen as a byproduct of their feeding activities. TNR: 916 pollution USE: contamination and pollution polonium BT: chemical elements RT: metal elements UF: Po SN: Metalloid element with symbol Po and atomic number 84 TNR: 1542 polychlorinated biphenyls USE: industrial pollution polymerase chain reaction BT: chemical analysis RT: biochemistry genetics SN: Biochemical technique that uses enzymes to replicate new nucleotides of DNA from DNA triphosphates using DNA as a template. TNR: 919 pond ecosystems USE: freshwater ecosystems population and community ecology BT: topics NT: animal behavior biodiversity biogeography community ecology ecosystems habitats population dynamics symbiosis RT: biological population management ecological processes ecology ecosystem monitoring natural resource management relative abundance analysis UF: life history population energetics radar ecology SN: Interactions of a single species (population) or an association of different species (community) occupying a particular region, including their biotic and abiotic environments. TNR: 921 population dynamics BT: population and community ecology RT: algal blooms biogeography ecology SN: Changes in the size, composition, or structure of aggregates of single or multiple species in a specific area over time. TNR: 922 population energetics USE: population and community ecology porosity BT: earth material properties UF: interstices soil porosity SN: The proportion of open space in a rock or unconsolidated material. TNR: 1369 posters BT: product types SN: Large single sheets of paper or board imprinted with informative text and graphics. Intended for hanging or flat display. TNR: 924 potable water USE: drinking water use potassium BT: chemical elements RT: alkali metal elements UF: K SN: Alkali metal element with symbol K and atomic number 19 TNR: 1543 potassium-argon analysis BT: radiometric dating UF: K-Ar dating SN: Radiometric age determination by comparison of the concentrations of radioactive potassium and argon daughter products. TNR: 1374 potentiometric surface USE: ground-water level power generation water use BT: instream water use RT: hydraulic engineering hydrology UF: hydroelectric power generation water use thermoelectric power generation water use SN: Use of water in the process of producing electric energy by transforming other forms of energy. TNR: 925 powerpoint USE: presentation materials Pr USE: praseodymium prairie ecosystems USE: grassland ecosystems praseodymium BT: chemical elements RT: lanthanide series elements UF: Pr SN: Rare earth (lanthanide series) element with symbol Pr and atomic number 59 TNR: 1545 precambrian BT: geologic time periods NT: archaean hadean proterozoic UF: cryptozoic TNR: 1655 precipitation (atmospheric) BT: atmospheric and climatic processes RT: hydrologic processes atmospheric deposition (chemical & particulate) atmospheric sciences hydrology storms water cycle UF: rainfall measurement snowfall measurement precipitation measurement rain rainfall snow snowfall SN: Any or all forms of water particles that fall from the atmosphere, such as rain, snow, hail and sleet. TNR: 927 precipitation measurement US+: field inventory and monitoring precipitation (atmospheric) predators USE: carnivores presentation materials BT: product types UF: powerpoint SN: Diagrams, photos, and text gathered together as part of a presentation given in a meeting or class. TNR: 1738 press relations (USGS) USE: USGS media relations press releases USE: news releases price lists (USGS) USE: USGS sales and distribution services pricing and ordering (USGS) USE: USGS sales and distribution services proceedings USE: reports producers (organisms) BT: organism groupings (non-taxonomic) RT: botany ecology microbiology SN: Organisms, chiefly green plants, which use inorganic elements, compounds, and light to produce their food (photosynthesis). They are a source of food for animals. TNR: 935 product support (USGS) USE: USGS product support product types BT: Categories NT: official communications catalogs and indexes datasets reports image collections maps and atlases posters scientific software videos materials standards presentation materials sound recordings animations terminologies and classifications SN: General representation of the information in a resource, such as a map or data set. TNR: 808 programs (USGS) USE: USGS programs prometium BT: chemical elements RT: lanthanide series elements UF: Pm SN: Rare earth (lanthanide series) element with symbol Pm and atomic number 61 TNR: 1546 prospecting USE: natural resource exploration protactinium BT: chemical elements RT: actinide series elements UF: Pa SN: Rare earth (actinide series) element with symbol Pa and atomic number 91 TNR: 1547 proterozoic BT: precambrian NT: Neoproterozoic TNR: 1656 protists BT: organisms RT: algae microbiology micropaleontology UF: foraminifera protozoans radiolaria SN: Unicellular eukaryotes (organisms possessing nucleated cells) with affinities to both plants and animals. Classed in the Protista or Potoctista kingdom, they include protozoans, foraminifera, radiolarians, fungi and some algae. TNR: 940 protozoans USE: protists Pt USE: platinum Pu USE: plutonium publication servers (USGS) USE: USGS publication servers public water supply USE: domestic water use published series USE: reports pyroclastic USE: volcanic rocks pyroclastic flows USE: volcanic activity quadrangle maps US+: topography maps and atlases quarrying USE: mining and quarrying quaternary BT: cenozoic NT: holocene pleistocene TNR: 1657 Ra USE: radium radar ecology US+: population and community ecology doppler radar imaging radar imaging BT: remote sensing NT: SLAR doppler radar imaging RT: geography microwave imaging SN: A remote sensing technique which uses the reflection of pulsed high frequency radio waves to determine the speed, direction, and distance of faraway objects. TNR: 948 radar tomography USE: tomography radioactive waste repositories USE: waste treatment and disposal radioactivity BT: earth material properties SN: Release of subatomic particles from earth materials. Generally the energy of these particles is used to determine the chemical elements present. TNR: 1701 radiocarbon dating USE: carbon-14 analysis radioisotope tagging USE: plant and animal tagging radioisotope tracer study USE: tracer study radiolaria USE: protists radiometric age determination USE: radiometric dating radiometric dating BT: isotopic analysis NT: carbon-14 analysis rubidium-strontium analysis uranium-lead analysis uranium-thorium analysis potassium-argon analysis RT: fission-track dating geochronology age estimation methods UF: age dating (radiometric) argon-argon dating lead-210 dating radiometric age determination SN: Methods for age determination of rocks and fossils by measuring the proportions of naturally occurring radioactive isotopes to their decay products. TNR: 954 radio telemetry USE: telemetry radium BT: chemical elements RT: alkaline earth elements UF: Ra SN: Alkaline earth element with symbol Ra and atomic number 88 TNR: 1551 radon BT: chemical elements RT: toxic radionuclide contamination noble gas elements UF: Rn SN: Noble gas element with symbol Rn and atomic number 86 TNR: 1552 rain USE: precipitation (atmospheric) rainfall USE: precipitation (atmospheric) rainfall measurement US+: precipitation (atmospheric) field inventory and monitoring rangeland ecosystems USE: terrestrial ecosystems rare earth elements BT: chemical element groups NT: actinide series elements lanthanide series elements TNR: 1553 Rb USE: rubidium Rb-Sr age analysis USE: rubidium-strontium analysis Re USE: rhenium re-establishment (organisms) USE: reintroduction (organisms) reaches (hydraulic) USE: river reaches reaches (streams) USE: river reaches reaction transport BT: geochemical processes RT: ground-water flow SN: Chemical reactions occurring during ground-water flow. TNR: 1711 real-time data USE: real-time monitoring and reporting real-time monitoring and reporting BT: field methods UF: real-time data SN: Gathering information through periodic or continuous measurement in the field to provide a view of current conditions. In some instances, observations may not be subject to rigorous review before release; this will be noted in the documentation accompanying the data. TNR: 1351 recharge USE: water cycle reclaimed water USE: water resource management reclamation USE: remediation recolonization (organisms) USE: reintroduction (organisms) reconnaissance USE: field inventory and monitoring recreation BT: topics UF: biking bird watching boating camping canoeing caving climbing fishing (recreational) hiking hunting kayaking SN: Pursuit of leisure-time activities, typically out of doors. TNR: 1352 recreational fishery resources BT: fishery resources RT: aquatic biology ichthyology marine biology UF: recreational fishing sport fishing SN: The stock of fish and other seafood resources in areas used for recreational fishing. TNR: 968 recreational fishing USE: recreational fishery resources red tides USE: algal blooms reef ecosystems BT: marine ecosystems RT: coelenterates ecology marine biology marine fishery resources UF: coral reef ecosystems SN: Biological communities formed by the skeletons of calcareous seawater organisms, usually corals. TNR: 971 reef fisheries USE: marine fishery resources reef fishing USE: marine fishery resources regression analysis BT: statistical analysis UF: correlation SN: Statistical analysis based on the functional relationships of two or more related variables. Predicts the value of one variable when the other two are given. TNR: 974 regulations USE: policies and regulations regulations (USGS) USE: USGS policies and regulations reintroduction (organisms) BT: biological population management UF: re-establishment (organisms) recolonization (organisms) SN: Return of a species to an area through the intervention of man. TNR: 977 relative abundance analysis BT: computational methods RT: ecosystem monitoring population and community ecology SN: Determination of the percentage of individuals of one group in comparison to the total of all individuals in a given area. TNR: 978 relief maps US+: maps and atlases topography remanent magnetism BT: magnetism UF: natural remanent magnetism SN: Magnetic characteristic of rocks and deposits reflective of the earth's magnetic field at the time of the deposit's formation. TNR: 1676 remediation BT: natural resource management NT: bioremediation RT: ecology ecosystem monitoring engineering geology UF: mitigation reclamation restoration SN: Methods for decontaminating, reclaiming, and restoring natural resources or reducing the effects of hazards. TNR: 980 remote-sensing data US+: image collections remote sensing remote-sensing images US+: image collections remote sensing remote sensing BT: methods NT: aeromagnetic surveying aeroradiometric surveying hyperspectral imaging IFSAR infrared imaging LIDAR microwave imaging multispectral imaging panchromatic imaging radar imaging thermal imaging visible light imaging RT: aerial photography geography seismic methods telemetry videography UF: remote-sensing data remote-sensing images airborne imaging composite burn index normalized burn ratio photogrammetry satellite altimetry satellite imaging space-borne sensing satellite images SN: The process of detecting and monitoring the physical characteristics of an area by measuring its reflected and emitted radiation at a distance from the targeted area. Remote sensing is used in this thesaurus to refer to methods that are solely or primarily deployed through air or space. Included in this concept are studies of biological populations using remote imaging techniques. Related methods which are used most frequently on the ground (e.g. photography), whether underwater, from airplanes or satellites, are not included in the term "remote sensing." TNR: 981 remote video monitoring USE: video monitoring reports BT: product types NT: checklists guidebooks manuals standards RT: bibliographies catalogs and indexes directories policies and regulations UF: abstracts articles (publications) biographies books and book chapters dissertations documents guidelines journal articles journals memos newsletters pamphlets, brochures, and booklets papers (publications) planning reports proceedings published series scientific reports serial publications technical reports text documents theses transcripts workshop reports yearbooks SN: Written items, especially those that are official, factual, or informative, often including graphics as well as text. TNR: 277 reptiles BT: vertebrates NT: dinosaurs RT: herpetology SN: Cold-blooded vertebrates of the class Reptilia. Characterized by skin covered with scales or horny plates and reproduced by eggs. Includes snakes, lizards, crocodiles, alligators, turtles, and extinct species such as dinosaurs. TNR: 988 residential water use USE: domestic water use resistivity BT: earth material properties SN: Electrical resistance of materials, often measured in boreholes. TNR: 1712 resistivity sounding USE: electrical resistivity logging resource assessment USE: natural resource assessment resource conservation USE: natural resource management resource extraction USE: natural resource extraction resource restoration USE: natural resource management restoration USE: remediation revegetation USE: bioremediation Rf USE: rutherfordium Rh USE: rhodium rhenium BT: chemical elements RT: metal elements UF: Re SN: Metal element with symbol Re and atomic number 75 TNR: 1558 rheology USE: deformation (geologic) rhodium BT: chemical elements RT: metal elements UF: Rh SN: Metal element with symbol Rh and atomic number 45 TNR: 1559 riparian ecosystems USE: wetland ecosystems risk assessment BT: management methods NT: earthquake probabilities landslide susceptibility assessment volcanic eruption prediction SN: The evaluation of the likelihood of adverse effects due to a given factor such as energy development or recurring hazardous events such as earthquakes. TNR: 997 river discharge USE: stream discharge river discharge monitoring USE: field inventory and monitoring river ecosystems US+: river systems freshwater ecosystems river reaches BT: river systems RT: hydrology UF: reaches (hydraulic) reaches (streams) SN: Continuous parts of streams between two specified points. TNR: 1001 river systems BT: surface water (non-marine) NT: river reaches RT: hydrology stream discharge UF: river ecosystems SN: Long water courses including main streams and tributaries. TNR: 1002 Rn USE: radon rock composition USE: rocks and deposits rockfalls USE: landslides rock mechanics maps US+: maps and atlases engineering geology rocks and deposits BT: earth characteristics NT: permafrost fossils igneous rocks metamorphic rocks sedimentary rocks unconsolidated deposits RT: building stone resources lithosphere petrography petrology meteorites UF: crystals lithologic maps lithology rock composition SN: Solid masses that make up the earth's crust as well as accumulations of materials. Use for major rock types and unconsolidated deposits. For deposits of economic value, see related terms. TNR: 1005 roundworms BT: worms RT: invertebrate zoology UF: nematodes SN: Worms of the phylum Nematoda, often parasitic, such as hookworms and pinworms, having soft cylindrical bodies without segments. TNR: 1006 Ru USE: ruthenium rubidium BT: chemical elements RT: alkali metal elements UF: Rb SN: Alkali metal element with symbol Rb and atomic number 37 TNR: 1562 rubidium-strontium analysis BT: radiometric dating RT: geochronology UF: Rb-Sr age analysis SN: Technique for dating ancient rocks based on measuring the ratio of the isotopes strontium-87 to ribidium-87 in samples. Uses the known half-life of radioactive isotopes of rubidium-87 that decay to isotopes of strontium-87 to determine rock ages. TNR: 1007 runoff BT: hydrologic processes UF: stormwater runoff urban runoff SN: Flow of water over land surfaces (including paved surfaces), typically from precipitation. TNR: 1375 rural water use USE: agricultural water use ruthenium BT: chemical elements RT: metal elements UF: Ru SN: Metal element with symbol Ru and atomic number 44 TNR: 1563 rutherfordium BT: chemical elements RT: metal elements UF: Rf SN: Metal element with symbol Rf and atomic number 104 TNR: 1564 S USE: sulfur safety issues (human) USE: human environmental safety sales services (USGS) USE: USGS sales and distribution services salinity BT: water properties RT: hydrology ocean salinity water chemistry UF: chloride concentration SN: Measure of the concentration of salts dissolved in a solution. TNR: 1010 salt-water intrusion USE: saltwater intrusion saltwater intrusion BT: hydrologic processes UF: salt-water intrusion SN: Infusion of saline waters in an aquifer or body of surface water. TNR: 1686 samarium BT: chemical elements RT: lanthanide series elements UF: Sm SN: Rare earth (lanthanide series) element with symbol Sm and atomic number 62 TNR: 1566 sand deposits BT: unconsolidated deposits RT: economic geology nonmetallic mineral resources sedimentology SN: Deposits of loose particles of rock or mineral (sediment) that range in size from 0.0625-2.0 millimeters in diameter. TNR: 1011 SAR interferometry USE: IFSAR satellite altimetry US+: remote sensing altimetry measurement satellite images US+: image collections remote sensing satellite imaging USE: remote sensing satellite photography USE: visible light imaging Sb USE: antimony Sc USE: scandium scandium BT: chemical elements RT: metal elements UF: Sc SN: Metal element with symbol Sc and atomic number 21 TNR: 1569 scanning electron microscopy BT: electron microscopy SN: Microscope in which a finely focused beam of electrons is scanned across a specimen. The electronic intensity variations observed are used to construct an image of the specimen. TNR: 1014 Scanning Multichannel Microwave Radiometer (SMMR) USE: SMMR school programs (USGS) USE: USGS K-12 programs science centers (USGS) USE: USGS science centers science programs (USGS) USE: USGS science programs sciences BT: Categories NT: earth sciences engineering sciences information sciences life sciences planetary sciences social sciences SN: Major educational fields, fields of study, and professional groupings within USGS. TNR: 1019 scientific careers BT: topics RT: earth sciences engineering sciences information sciences life sciences planetary sciences social sciences UF: careers in science scientists-at-work photographs SN: Professions in which people carry out or support scientific research or monitoring. TNR: 1020 scientific reports USE: reports scientific software BT: product types UF: computer program SN: Routines, programs, and procedures devised in order to direct computers to perform specific tasks. TNR: 1077 scientists-at-work photographs US+: image collections scientific careers sclerochronology BT: age estimation methods SN: Description of the history of individual organisms by studying the variations in thickness of accretionary layers in their skeletons. TNR: 1713 scour BT: hydrologic processes RT: hazards erosion UF: bridge scour SN: Erosion of sediment in a stream bed, often occurring at manmade structures such as bridge supports. TNR: 1687 scrubland ecosystems USE: shrubland ecosystems Se USE: selenium sea-floor characteristics BT: ocean characteristics RT: bathymetry land surface characteristics marine geology ocean sciences oceanic lithosphere UF: ocean bottom characteristics sea floor characteristics seafloor characteristics SN: Geomorphic features and geographic, compositional, and textural variation in the materials composing the ocean floor. Includes both large-scale structures (such as seamounts and rises) and fine-scale variations in rocks and deposits on the sea floor. TNR: 1025 sea-ice concentration USE: sea ice concentration sea-level change BT: ocean characteristics RT: climatology global change ocean sciences UF: sea-level rise SN: Variation in the relative vertical position of land and ocean waters. Caused globally by changes in the distribution of ice masses and the shape of the oceans, and locally by the rate of uplift or subsidence of the land surface. Includes both global (eustatic) and local (relative) sea-level variations. TNR: 1028 sea-level rise USE: sea-level change sea-surface temperature USE: sea surface temperature sea anemones USE: coelenterates seaborgium BT: chemical elements RT: metal elements UF: Sg SN: Metal element with symbol Sg and atomic number 106 TNR: 1571 seafloor characteristics USE: sea-floor characteristics sea floor characteristics USE: sea-floor characteristics sea floor topography USE: bathymetry seagrass USE: aquatic vegetation sea ice concentration BT: snow and ice cover RT: ocean characteristics UF: sea-ice concentration sea ice cover SN: Proportion of ocean area in a given region that contains or is covered by floating ice. TNR: 1722 sea ice cover USE: sea ice concentration search services (USGS) USE: USGS search services seasonal migration USE: migration (organisms) seasons BT: time periods NT: autumn spring (season) summer winter TNR: 1658 sea squirts USE: tunicates sea surface temperature BT: ocean temperature RT: AVHRR UF: sst temperature (sea surface) sea-surface temperature SN: Observed temperature of surface ocean waters, typically encompassing the entire mixed layer. Some observational methods, however, may measure a much smaller depth range. Includes temperature data obtained in-situ or by remote sensing methods. TNR: 1027 seaweeds USE: aquatic vegetation sections (geologic) USE: stratigraphic sections sections (stratigraphic) USE: stratigraphic sections sedimentary rocks BT: rocks and deposits NT: bedforms RT: petrology sedimentation sedimentology SN: Rocks formed by the consolidation of loose, uncemented pieces of sediments. TNR: 1035 sedimentation BT: geologic processes RT: sedimentary rocks sedimentology atmospheric deposition (chemical & particulate) UF: alluvial sedimentation deposition (sediment) dust deposition SN: Process of deposition of sediments (loose, uncemented pieces of rock, mineral fragments, or biological materials). The sediments settle out of water or air into layers on a surface. TNR: 1036 sediment geochemistry US+: unconsolidated deposits chemical analysis sedimentology BT: geology RT: bedforms building stone resources clay deposits diagenesis erosion grain-size analysis gravel deposits sand deposits sediment transport sedimentary rocks sedimentation sieve-size analysis trenching SN: Branch of earth sciences concerned with the study of the origin, composition, transport, and changes of materials deposited by water, wind, or ice. TNR: 1037 sediments USE: unconsolidated deposits sediment transport BT: geologic processes RT: hydrology sedimentology UF: alluvial transport bed load bedload density flow dust transport suspended load turbidity flow SN: Transport of solid particles of unconsolidated rock and mineral fragments, chemical precipitates, or biological materials. TNR: 1034 segmented worms BT: worms RT: invertebrate zoology UF: annelids SN: Worms belonging to the phylum Annelida, with soft bodies divided into segments and distinct heads. Includes leeches, earthworms, and marine worms. TNR: 1038 seismic activity USE: earthquake occurrences seismic exploration US+: seismic methods natural resource exploration seismic hazard maps US+: earthquake occurrences maps and atlases seismic imaging USE: seismic methods seismicity USE: earthquake occurrences seismicity maps US+: maps and atlases earthquake probabilities seismic methods BT: field inventory and monitoring NT: seismic networking seismic reflection method seismic refraction method RT: remote sensing seismology UF: seismic exploration seismic imaging seismic profiles seismograms seismometry SN: Procedures used to record and study earthquakes or earth vibrations including those that are artificially induced. TNR: 1042 seismic monitoring stations USE: field monitoring stations seismic networking BT: seismic methods RT: seismology UF: earthquake monitoring SN: Deploying, operating, and maintaining groups and arrays of instruments for detecting and describing local movements of the earth. TNR: 1043 seismic profiles USE: seismic methods seismic reflection method BT: seismic methods RT: seismology UF: seismic reflection survey maps SN: Geophysical technique to study the subsurface of the earth using sound waves induced by explosives, vibrating devices, or percussive equipment. The reflections of the sound waves from the boundaries of different rocks are measured. TNR: 1045 seismic reflection survey maps US+: maps and atlases seismic reflection method seismic refraction method BT: seismic methods RT: seismology SN: Geophysical technique to study the subsurface of the earth by generating compressional waves by means of hammering or explosive methods. The variations in velocity of the waves traveling through rocks or geological layers are measured. TNR: 1047 seismic tomography USE: tomography seismograms USE: seismic methods seismology BT: geophysics NT: paleoseismology RT: earthquake occurrences earthquakes seismic methods seismic networking seismic reflection method seismic refraction method tectonic processes tiltmeter measurement tsunamis volcanology UF: earthquake seismology engineering seismology exploration seismology SN: Branch of earth sciences concerned with the study of earthquakes and man-induced seismic waves. TNR: 1050 seismometry USE: seismic methods selenium BT: chemical elements RT: nonmetal elements UF: Se SN: Nonmetal element with symbol Se and atomic number 34 TNR: 1572 serial publications USE: reports sewage disposal USE: waste treatment and disposal sexing (plants & animals) BT: field sampling RT: life sciences UF: sexing (plants and animals) SN: Determination of the sex of an individual organism for study purposes, such as wildlife surveys. TNR: 1054 sexing (plants and animals) USE: sexing (plants & animals) Sg USE: seaborgium shaking maps (seismic) US+: maps and atlases earthquake occurrences shellfish BT: organism groupings (non-taxonomic) RT: aquatic biology crustaceans invertebrate zoology mollusks SN: Aquatic invertebrates with shells, usually mollusks and crustaceans. Includes clams, lobsters, and oysters. TNR: 1056 shorebirds USE: birds short grass ecosystems USE: grassland ecosystems shrubland ecosystems BT: terrestrial ecosystems RT: ecology UF: scrubland ecosystems SN: Biological land communities and habitats with sparse, low-growing vegetation. TNR: 1059 Side-Looking Airborne Radar (SLAR) USE: SLAR side-scan sonar methods BT: sonar methods RT: marine geology marine geophysics UF: Sidescan sonar methods SN: Techniques of collecting data from the sea floor by towing a vehicle with SOund NAvigation and Ranging systems projecting beams of sound waves into the underwater environment. Data are collected from the returning echoes (backscatter) as the sound waves are relected back from the sea floor or sediments. TNR: 1061 Sidescan sonar methods USE: side-scan sonar methods sieve-size analysis BT: grain-size analysis RT: sedimentology SN: Analytic technique determining the distribution of the different sizes of particles in soil, sediment, or rock samples by measuring the percentage that will pass through mesh holes of known size. TNR: 1062 silicon BT: chemical elements RT: nonmetal elements SN: Nonmetal element with symbol si and atomic number 14 TNR: 1575 silurian BT: paleozoic TNR: 1659 silver BT: chemical elements RT: metal elements UF: Ag SN: Metal element with symbol Ag and atomic number 47 TNR: 1576 sinkhole formation USE: erosion SLAR BT: radar imaging RT: geography UF: Side-Looking Airborne Radar (SLAR) SN: Side-looking Airborne Radar, an airborne radar imaging technique, uses an antenna mounted on an airplane or satellite to project radiation at right angles to the flight path and collect high resolution images. TNR: 1064 slides (land) USE: landslides slope stability USE: landslide susceptibility assessment slope stability maps US+: landslide susceptibility assessment maps and atlases slumps USE: mass wasting Sm USE: samarium SMMR BT: microwave imaging RT: geography UF: SMMR images Scanning Multichannel Microwave Radiometer (SMMR) SN: Scanning Multichannel Microwave Radiometer (SMMR), a technique which uses a multichannel microwave radiometer mounted on an airplane or satellite to measure polarized microwave radiances from the atmosphere, seas or land. Temperatures, wind speeds, sea ice coverage, and terrain parameters can be obtained. TNR: 1069 SMMR images USE: SMMR Sn USE: tin snow USE: precipitation (atmospheric) snow and ice cover BT: earth characteristics NT: sea ice concentration RT: atmospheric and climatic processes glaciation glaciology SSM/I surface water (non-marine) UF: cryosphere glaciers ice core sampling ice snowpack SN: Accumulation of snow or ice blanketing land surfaces. TNR: 1072 snowfall USE: precipitation (atmospheric) snowfall measurement US+: field inventory and monitoring precipitation (atmospheric) snowpack USE: snow and ice cover social sciences BT: sciences NT: archeology RT: business and economics cadastral and legal land descriptions culture and demographics environmental health (human) hazards health and disease human environmental safety human impacts land use change mining hazards overfishing scientific careers waste treatment and disposal SN: Sciences concerned with the structure and interrelationships of human societies, human institutions and organizations, and human culture over time. TNR: 1075 socioeconomics USE: culture and demographics sodium BT: chemical elements RT: alkali metal elements UF: Na SN: Alkali metal element with symbol Na and atomic number 11 TNR: 1579 soil chemistry BT: geochemistry RT: agriculture soil resources soil sciences SN: Branch of chemistry concerned with the elements and compounds that make up soils. Includes chemical processes involving soils. TNR: 1078 soil compaction USE: compaction soil formation BT: geologic processes RT: ecological processes geochemical processes UF: pedogenesis SN: Geological, geochemical, and ecological processes that work together to produce soils. TNR: 1710 soil permeability USE: permeability soil pollution US+: contamination and pollution soil resources soil porosity USE: porosity soil resources BT: natural resources RT: economic geology soil chemistry soil sciences UF: soil pollution SN: Natural resources of unconsolidated fragmented rock, humus, and mineral matter that cover the surface of the earth. TNR: 1080 soil sciences BT: earth sciences RT: soil chemistry soil resources trenching UF: pedology (soils) SN: Earth sciences dealing with the origin, classification, physical, chemical, and biological properties of soils. TNR: 1081 sonar depth-sounding USE: sonar methods sonar methods BT: acoustic methods NT: side-scan sonar methods RT: bathymetry measurement UF: echo sounding sonar depth-sounding SN: SOund Navigation And Ranging techniques to detect submerged objects and to determine depths to the sea floor using reflections of sound waves. TNR: 1083 sorption BT: geochemical processes UF: adsorption absorption SN: Attachment of chemical substances to materials, either externally (by adsorption) or internally (by absorption). TNR: 1715 sound recordings BT: product types UF: audio recordings podcasts SN: Information presented in a format for listening by the user. TNR: 1739 space-borne sensing USE: remote sensing spatial analysis BT: computational methods NT: geospatial analysis RT: geography image analysis mathematical modeling topological analysis SN: Use of quantitative tools to study social, economic, and geographic data in relation to distributions and patterns in geographic space. TNR: 1085 Special Sensor Microwave/Imager (SSM/I) USE: SSM/I species distribution USE: biogeography species distribution maps US+: biogeography maps and atlases species diversity BT: biodiversity SN: An ecological concept incorporating both the number of species in a particular sampling area and the evenness with which individuals are distributed among the various species. TNR: 1089 species geographic range USE: biogeography specimen collecting BT: field sampling RT: capturing (animals) UF: collection of specimens SN: Taking of samples from the environment for study. TNR: 1091 speeches and testimony BT: official communications RT: USGS meetings UF: oral presentations talks testimony TNR: 1092 speleology USE: geomorphology spiders USE: arachnids sponges BT: invertebrates RT: invertebrate zoology SN: Aquatic invertebrates belonging to the phylum Porifera having internal skeletons of silica or collagen, porous body around a cavity or cavities, and usually living in stationary communities. TNR: 1094 sport fishing USE: recreational fishery resources spring (season) BT: seasons TNR: 1660 spring ecosystems USE: freshwater ecosystems Sr USE: strontium SSM/I BT: microwave imaging RT: geography snow and ice cover UF: SSM/I images Special Sensor Microwave/Imager (SSM/I) SN: Special Sensor Microwave/Imager (SSM/I), technique using passive microwave radiometers aboard satellites to measure the microwave reflectivity of the earth, oceans, and the atmosphere. TNR: 1097 SSM/I images USE: SSM/I sst USE: sea surface temperature stable isotope analysis USE: light stable isotope analysis standard reference samples USE: materials standards standards BT: reports RT: USGS standards development SN: An object or instrument of known properties used as a model, for comparison, or a set of rules used to assure quality. TNR: 1099 standards development (USGS) USE: USGS standards development statistical analysis BT: computational methods NT: kriging multivariate statistical analysis regression analysis time series analysis UF: geostatistics SN: Branch of mathematics concerned with techniques to collect and interpret data. TNR: 1101 statutes USE: laws and regulations storms BT: atmospheric and climatic processes NT: blizzards hurricanes ice storms tornadoes dust storms RT: hazards meteorology precipitation (atmospheric) SN: Atmospheric disturbances with winds of unusual force or direction. Accompanied by rain, snow, hail, or sleet, and often by thunder and lightning. TNR: 1102 storm surge BT: floods SN: Coastal high water level caused by wind from storms. TNR: 1730 stormwater runoff USE: runoff strain history USE: deformation (geologic) stratigraphic sections BT: earth characteristics NT: bedrock geologic units geologic contacts surficial geologic units RT: geologic structure stratigraphy UF: geologic sections geologic units sections (geologic) sections (stratigraphic) SN: Vertical arrangement in layers of rock units whose sequence is used to study the geological history of the strata. TNR: 1103 stratigraphy BT: geology RT: bedrock geologic units biostratigraphy borehole logging electrical resistivity logging gamma-ray logging geochronology geologic contacts geologic history lithostratigraphy stratigraphic sections surficial geologic units unconformities SN: Branch of geology concerned with the study of the formation, composition, ordering in time, and arrangement in space of stratified rocks. TNR: 1104 stream-flow monitoring USE: stream-gage measurement stream-gage measurement BT: field inventory and monitoring RT: hydrology streamflow acoustic doppler current profiling UF: gage-height monitoring stream current monitoring stream flow monitoring stream gage monitoring stream-flow monitoring stream-gage monitoring streamflow monitoring SN: Use of specialized instruments designed for observing, checking, and recording the water discharge that occurs in a natural channel. TNR: 1116 stream-gage monitoring USE: stream-gage measurement stream current USE: streamflow stream current monitoring USE: stream-gage measurement stream discharge BT: streamflow RT: hydrology river systems surface water (non-marine) UF: river discharge stream discharge monitoring SN: Volume of water in a stream passing a given point at a given moment in time, expressed as a measure of volume per unit of time, i.e. cubic feet per second, million gallons per day, or gallons per minute. TNR: 998 stream discharge monitoring USE: stream discharge stream ecosystems USE: freshwater ecosystems streamflow BT: hydrologic processes NT: stream discharge turbidity RT: hydrology stream-gage measurement surface water (non-marine) water circulation watershed management surface-water level UF: flood stage fluvial processes gage height stream current stream flow stream stage streamflow data streamflow modeling SN: A type of channel flow, applied to a specific part of surface runoff in a stream, whether or not it is affected by diversion or regulation. TNR: 1113 stream flow USE: streamflow streamflow data US+: datasets streamflow streamflow modeling US+: mathematical modeling streamflow stream flow monitoring USE: stream-gage measurement streamflow monitoring USE: stream-gage measurement stream gage monitoring USE: stream-gage measurement stream gaging stations USE: field monitoring stations stream stage USE: streamflow strong motion USE: earthquake occurrences strontium BT: chemical elements RT: alkaline earth elements UF: Sr SN: Alkaline earth element with symbol Sr and atomic number 38 TNR: 1581 structural geology BT: geology RT: earth structure folding (geologic) foliation (geologic) fracture (geologic) geologic structure lineation (geologic) neotectonic processes structure contours tectonic processes tectonophysics SN: Branch of geology concerned with the distribution, position, shape, and internal structure of rocks. TNR: 1117 structure contours BT: geologic structure RT: structural geology UF: depth-to maps thickness maps SN: Gridding and contouring lines drawn on geologic maps to depict boundaries of structural features. TNR: 1118 subbituminous coal resources USE: coal resources subduction USE: tectonic processes subsistence fishery resources BT: fishery resources SN: The stock of fish taken and eaten by local populations rather than marketed. TNR: 1121 subsurface maps US+: geology maps and atlases succession (biological) BT: ecological processes RT: ecology UF: ecologic succession SN: Gradual replacement of one species in an area by another. TNR: 1123 sulfur BT: chemical elements RT: nonmetal elements UF: S SN: Nonmetal element with symbol S and atomic number 16 TNR: 1582 summer BT: seasons TNR: 1661 surface-water/ground-water interaction USE: ground-water and surface-water interaction surface-water level BT: surface water (non-marine) RT: ground-water level streamflow SN: Height of the water surface in a lake or reservoir. For water levels in flowing streams, refer to streamflow. TNR: 1743 surface water (non-marine) BT: water resources NT: river systems surface-water level RT: floods freshwater ecosystems hydrology limnology ocean characteristics ocean processes stream discharge snow and ice cover streamflow surface water quality UF: freshwater (surface) SN: Open bodies of water, such as lakes, rivers, or streams. All non-marine waters on the surface of the earth, including fresh, brackish, and salt water. TNR: 1124 surface water/ground water interaction USE: ground-water and surface-water interaction surface water quality BT: water quality RT: hydrology limnology surface water (non-marine) water chemistry SN: Chemical, physical, and biological characteristics of water in lakes, rivers, or streams related to its fitness for use. TNR: 1125 surficial deposits USE: unconsolidated deposits surficial geologic maps US+: surficial geologic units maps and atlases surficial geologic units BT: stratigraphic sections RT: stratigraphy UF: surficial geologic maps SN: Rock units on the earth's surface. TNR: 1127 surveying USE: land surveying suspended load USE: sediment transport suspended material (water) BT: water properties RT: hydrology water chemistry SN: Sediment or particles of rock, sand, soil, and organic detritus carried in suspension in the water column, in contrast to sediment that moves on or near the streambed. TNR: 1129 symbiosis BT: population and community ecology UF: commensalism mutualism parasitism SN: An intimate, prolonged association between two or more organisms of different species that may or may not benefit each member. TNR: 1688 symposia (USGS) USE: USGS symposia systematics and taxonomy BT: life sciences RT: meristics UF: taxonomy SN: Study of the identification, naming, and classification of organisms. TNR: 1131 Ta USE: tantalum tagging USE: plant and animal tagging taiga ecosystems USE: forest ecosystems talks USE: speeches and testimony tall grass ecosystems USE: grassland ecosystems tantalum BT: chemical elements RT: metal elements UF: Ta SN: Metal element with symbol Ta and atomic number 73 TNR: 1584 taphonomy USE: paleontology tar sand resources USE: oil sand resources taxonomy USE: systematics and taxonomy Tb USE: terbium Tc USE: technetium Te USE: tellurium technetium BT: chemical elements RT: metal elements UF: Tc SN: Metal element with symbol Tc and atomic number 43 TNR: 1588 technical instructions USE: manuals technical reports USE: reports technical support (USGS) USE: USGS technical support technology transfer (USGS) USE: USGS technology transfer tectonic maps US+: tectonic processes maps and atlases tectonic processes BT: geologic processes NT: neotectonic processes RT: earth structure earthquakes folding (geologic) foliation (geologic) fracture (geologic) lineation (geologic) seismology structural geology tectonophysics volcanic activity UF: continental drift dynamic geology paleotectonic maps plate tectonics subduction tectonic maps tectonics wilson cycle SN: The structural forces affecting the deformation, uplift, and movement of the earth's crust. TNR: 1145 tectonics USE: tectonic processes tectonophysics BT: geophysics RT: asthenosphere continental lithosphere crust (earth) earth history earth structure earthquakes lithosphere neotectonic processes oceanic lithosphere structural geology tectonic processes volcanology SN: Branch of geophysics concerned with the structural forces affecting the deformation, uplift, and movement of the earth's crust. TNR: 1147 telemetry BT: field inventory and monitoring RT: animal tracking remote sensing UF: biotelemetry radio telemetry SN: Field technique using instruments which measure heat, radiation, speed, or other property and transmit the data to a distant receiver. TNR: 1148 tellurium BT: chemical elements RT: nonmetal elements UF: Te SN: Nonmetal element with symbol Te and atomic number 52 TNR: 1589 temperature (air) USE: air temperature temperature (ocean) USE: ocean temperature temperature (sea surface) USE: sea surface temperature temperature (water) USE: water temperature temperature analysis (Curie) USE: Curie temperature analysis tephrochronology BT: age estimation methods RT: lithostratigraphy SN: Age determination of rocks and deposits by correlation of volcanic ash layers (tephra) that bound the deposits below and above. TNR: 1681 terbium BT: chemical elements RT: lanthanide series elements UF: Tb SN: Rare earth (lanthanide series) element with symbol Tb and atomic number 65 TNR: 1590 terminologies and classifications BT: product types NT: geologic time scales UF: glossaries controlled vocabularies SN: Collections of terms often including definitions or scope notes, with some stated relationships among terms TNR: 1744 terrestrial ecosystems BT: ecosystems NT: coastal ecosystems desert ecosystems forest ecosystems grassland ecosystems shrubland ecosystems tundra ecosystems island ecosystems RT: ecology wetland ecosystems UF: rangeland ecosystems SN: Communities of living organisms in a specific geographical location which exist primarily on land and not in water. TNR: 1156 tertiary BT: cenozoic NT: neogene paleogene TNR: 1662 testimony USE: speeches and testimony text documents USE: reports Th USE: thorium thallium BT: chemical elements RT: metal elements UF: Tl SN: Metalloid element with symbol Tl and atomic number 81 TNR: 1592 thematic mapper USE: multispectral imaging therapeutic methods BT: laboratory methods RT: anatomy and physiology ecotoxicology pathology SN: Methods of restoring health with remedial agents or treatments. TNR: 1160 thermal imaging BT: remote sensing RT: geography SN: Remote sensing techniques using instruments to measure emitted thermal radiation to form images of the earth's surface. TNR: 1161 thermoelectric power generation water use USE: power generation water use thermoluminescence dating USE: luminescence dating theses USE: reports thickness maps US+: structure contours maps and atlases thin section analysis USE: petrography thorium BT: chemical elements RT: actinide series elements UF: Th SN: Rare earth (actinide series) element with symbol Th and atomic number 90 TNR: 1593 thulium BT: chemical elements RT: lanthanide series elements UF: Tm SN: Rare earth (lanthanide series) element with symbol Tm and atomic number 69 TNR: 1594 Ti USE: titanium ticks USE: arachnids tidal waves USE: tsunamis tides (oceanic) BT: ocean processes RT: ocean circulation ocean currents ocean sciences UF: ocean tides SN: The periodic rise and fall of the level of the sea due to the gravitational attraction of the moon and sun. Occurs twice each day. TNR: 1168 tiltmeter USE: tiltmeter measurement tiltmeter measurement BT: field inventory and monitoring RT: seismology volcanology UF: tiltmeter SN: Determination of tiny changes in the slope angle or tilt of the ground in order to monitor deformation caused by moving magma. Instruments detect variations in a liquid level or in the position of a pendulum. TNR: 1169 time periods BT: Categories NT: geologic time periods seasons SN: Geologic time periods and seasons of the year TNR: 1663 time series analysis BT: statistical analysis RT: time series datasets SN: Statistical analysis using frequency distribution in which time is an independent variable. A sequence of observations collected at regular time intervals is studied. TNR: 1171 time series datasets BT: datasets RT: time series analysis SN: Digital information describing observations taken at regular time intervals. The time interval may vary; the type of observed phenomena and the location typically do not. TNR: 1172 tin BT: chemical elements RT: metal elements UF: Sn SN: Metalloid element with symbol Sn and atomic number 50 TNR: 1596 titanium BT: chemical elements RT: metal elements UF: Ti SN: Metal element with symbol Ti and atomic number 22 TNR: 1597 Tl USE: thallium TL/OSL dating USE: luminescence dating Tm USE: thulium TMDL BT: environmental assessment UF: total maximum daily load SN: A calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water-quality standards. TNR: 1380 tomography BT: field inventory and monitoring UF: seismic tomography radar tomography SN: Observation of the internal structure of an object or, as is more typical in USGS research, a cross section of the earth's crust by changing the relative orientation of a signal generator, a sensor, or both. TNR: 1716 tool development USE: instrument design and development topics BT: Categories NT: elements field monitoring stations recreation agriculture biological and physical processes culture and demographics earth characteristics global change hazards health and disease human impacts information system design and development instrument design and development land use and land cover map coordinate systems contamination and pollution natural resource exploration natural resource extraction natural resources organism groupings (non-taxonomic) organisms planetary bodies population and community ecology scientific careers water properties water quality water supply and demand SN: Themes, subjects, and concerns for which USGS information resources are relevant. TNR: 1174 topographic maps US+: topography maps and atlases topography BT: earth characteristics NT: bathymetry RT: geography geomorphology geospatial datasets UF: contour lines quadrangle maps relief maps elevation topographic maps SN: The shape of the land surface. TNR: 1176 topological analysis BT: computational methods RT: geography geospatial analysis spatial analysis SN: Branch of geometry concerned with the properties of objects that do not change even when deformed, twisted, stretched or otherwise changed in shape. TNR: 1177 tornadoes BT: storms RT: meteorology SN: Violent storms characterized by whirling funnels of wind moving at great speeds. TNR: 1178 total maximum daily load USE: TMDL tours (USGS) USE: USGS exhibits and facility tours toxicology USE: ecotoxicology toxic radionuclide contamination BT: contamination and pollution RT: ecotoxicology environmental health (human) radon SN: Introduction into the environment of unstable isotopes of elements that undergo radioactive decay, emitting radiation that is harmful to organisms. TNR: 1180 toxic trace element contamination BT: contamination and pollution NT: mercury contamination RT: ecotoxicology environmental health (human) SN: Introduction into the environment of elements (such as arsenic, cadmium, lead, and mercury) which have a deleterious effect on living organisms when found naturally in only minor amounts (concentrations less than 1.0 milligram per liter) in water or sediment. TNR: 1181 trace fossils USE: ichnofossils tracer study BT: field experiments UF: isotopic tracer study radioisotope tracer study SN: Experiments in which stable, easily detected substances or radioisotopes are added to a material to follow the movement of the substance in the environment or to detect any physical or chemical changes with time. TNR: 1376 tracking USE: animal tracking transcripts USE: reports transect sampling BT: field sampling RT: plot sampling trenching SN: Systematic method of collecting field data by recording observations or collecting specimens along a vector or measured course across the environment. TNR: 1186 transpiration BT: ecological processes RT: evaporation UF: evapotranspiration SN: Evaporation of water from plants. TNR: 1356 transportation BT: culture and demographics UF: air transportation aviation ground transportation SN: Movement of people or materials from one place to another for economic, political, or recreational purposes. TNR: 1689 trapping (animals) USE: capturing (animals) tree ring analysis BT: laboratory methods RT: geochronology age estimation methods UF: age dating (tree ring) SN: Study of the variations in width and number of tree rings to date historical events and to study periods of climatic and hydrologic changes. TNR: 1188 trees USE: vegetation trenching BT: field sampling RT: plot sampling sedimentology soil sciences transect sampling SN: Field method used by earth scientists to study the underground structure of an area. A long narrow ditch is dug to locate geologic features, such as a fault. TNR: 1189 triassic BT: mesozoic TNR: 1664 trilobites BT: arthropods RT: fossils invertebrate paleontology SN: Extinct marine arthropods of the class Trilobita with segmented bodies and jointed appendages found as Paleozoic fossils in many parts of the world. TNR: 1190 tritium-helium dating USE: tritium analysis tritium analysis BT: light stable isotope analysis RT: biochemistry geochemistry UF: tritium-helium dating SN: Mass spectrometric measurement of the decay of the radioactive isotope of hydrogen in water samples as a means of dating and investigating changes in water. TNR: 1191 trophic level dynamics USE: food web trophic relationships USE: food web tsunami preparedness US+: hazard preparedness tsunamis tsunamis BT: ocean waves RT: geologic processes hazards ocean sciences seismology UF: tidal waves tsunami preparedness SN: Large destructive sea waves generated by earthquakes, volcanic eruptions, or large landslides. TNR: 1195 tuff USE: volcanic rocks tundra ecosystems BT: terrestrial ecosystems RT: ecology SN: Biological communities and habitats located in the treeless plains of Arctic regions where the subsoil is permanently frozen. TNR: 1196 tungsten BT: chemical elements RT: metal elements UF: W SN: Metal element with symbol W and atomic number 74 TNR: 1600 tunicates BT: invertebrates UF: sea squirts urochordates SN: Marine organisms of the subphylum tunicata of the phylum chordata. TNR: 1733 turbidity BT: streamflow UF: turbulence SN: Internal roughness of the water column within a body of water. TNR: 1377 turbidity flow USE: sediment transport turbulence USE: turbidity typhoons USE: hurricanes U USE: uranium unconformities BT: geologic contacts RT: stratigraphy SN: The contact between older rocks and younger sedimentary rocks where erosion had removed some of the older rocks before the younger rocks were deposited. TNR: 1198 unconsolidated deposits BT: rocks and deposits NT: clay deposits gravel deposits sand deposits UF: alluvium eolian sediments loess sediments surficial deposits sediment geochemistry SN: Loosely bound sediments such as sand, gravel, and silt which tend to accumulate in low areas or valleys. TNR: 1199 underwater contours USE: bathymetry underwater photography BT: photography RT: ocean sciences UF: camera tows SN: Photographs taken below the water surface, usually in marine, lacustrine, and estuarine environments. Subjects are typically benthic organisms and sedimentary structures on the sea floor. TNR: 1201 unsaturated zone BT: ground-water level UF: vadose zone SN: The portion of the subsurface above the ground water table. TNR: 1717 ununnilium BT: chemical elements RT: metal elements UF: Uuu SN: Metal element with symbol Uuu and atomic number 111 TNR: 1602 ununnubium BT: chemical elements RT: metal elements UF: Uub SN: Metal element with symbol Uub and atomic number 113 TNR: 1603 ununnunium BT: chemical elements RT: metal elements UF: Uun SN: Metal element with symbol Uun and atomic number 112 TNR: 1604 upper carboniferous USE: pennsylvanian uranium BT: chemical elements RT: actinide series elements UF: U SN: Rare earth (actinide series) element with symbol U and atomic number 92 TNR: 1605 uranium-lead analysis BT: radiometric dating RT: geochronology SN: Radiometric dating technique to determine the age of earth materials from the ratio of the radioactive isotopes of uranium-235 or uranium-238 to the lead isotope decay products in the sample. The ratio is compared to the known half-life of the uranium isotopes. TNR: 1202 uranium-thorium analysis BT: radiometric dating RT: geochronology SN: Radiometric dating technique used to determine the age of earth materials based on determining the ratio of uranium-238 to the decay product thorium-230. The ratio is compared to the known half-life of the uranium isotope. TNR: 1203 urbanization USE: land use change urban runoff USE: runoff urochordates USE: tunicates user feedback (USGS) USE: USGS customer support and user feedback user guides USE: manuals user services (USGS) USE: USGS user services USGS BT: Categories NT: USGS budget USGS contracts and grants USGS facilities USGS news USGS organization USGS personnel USGS policies and regulations USGS programs USGS user services USGS community relations SN: Activities, processes, and organizational concepts relevant to USGS itself. TNR: 1208 USGS budget BT: USGS UF: budget (USGS) TNR: 1209 USGS clearinghouses BT: USGS information services RT: catalogs and indexes USGS search services UF: clearinghouses (USGS) TNR: 1210 USGS college programs BT: USGS educational services UF: college programs (USGS) TNR: 1211 USGS colloquia BT: USGS meetings UF: colloquia (USGS) TNR: 1212 USGS community involvement USE: USGS community relations USGS community relations BT: USGS UF: USGS community involvement SN: Interaction and communication with people and public organizations outside USGS to assist with decision-making, not specifically directed to general scientific education. TNR: 1695 USGS contracts and grants BT: USGS NT: USGS cooperative research & development agreements (CRADAs) USGS technology transfer UF: contracts (USGS) grants (USGS) TNR: 1213 USGS cooperative research & development agreements (CRADAs) BT: USGS contracts and grants RT: USGS partnerships UF: CRADAs cooperative research & development agreements (CRADAs) cooperative research and development agreements TNR: 1214 USGS customer support and user feedback BT: USGS user services NT: USGS product support USGS technical support UF: Frequently Asked Questions (FAQs) customer support (USGS) user feedback (USGS) TNR: 1215 USGS data downloading BT: USGS information services UF: data downloading (USGS) TNR: 1216 USGS disciplines BT: USGS organization UF: USGS divisions TNR: 1217 USGS divisions USE: USGS disciplines USGS Earth Science Information Centers (ESICs) BT: USGS information services RT: USGS sales and distribution services UF: ESICs Earth Science Information Centers (ESICs) TNR: 1218 USGS educational services BT: USGS user services NT: USGS college programs USGS internships USGS K-12 programs USGS lifelong learning programs USGS meetings UF: educational services (USGS) TNR: 1219 USGS employment and volunteer opportunities BT: USGS personnel UF: employment opportunities (USGS) volunteer opportunities (USGS) TNR: 1220 USGS exhibits and facility tours BT: USGS user services NT: USGS open houses UF: exhibits (USGS) facility tours (USGS) photo galleries (USGS) tours (USGS) TNR: 1221 USGS expertise services BT: USGS information services UF: Ask-A services (USGS) expertise services (USGS) TNR: 1222 USGS facilities BT: USGS NT: USGS field centers USGS laboratories USGS mapping centers USGS nuclear reactors USGS observatories USGS science centers USGS visitor centers UF: facilities (USGS) TNR: 1223 USGS fax-on-demand services BT: USGS information services UF: fax-on-demand (USGS) TNR: 1224 USGS field centers BT: USGS facilities UF: field centers (USGS) TNR: 1225 USGS information services BT: USGS user services NT: USGS clearinghouses USGS data downloading USGS Earth Science Information Centers (ESICs) USGS expertise services USGS fax-on-demand services USGS libraries and archives USGS map servers USGS media relations USGS publication servers USGS sales and distribution services USGS search services UF: accessing USGS data and products information centers (USGS) information services (USGS) TNR: 1226 USGS interagency programs BT: USGS programs UF: interagency programs (USGS) SN: Activities in which USGS works with other Federal agencies or non-governmental organizations. TNR: 1227 USGS international programs BT: USGS programs UF: international programs (USGS) TNR: 1228 USGS internships BT: USGS educational services UF: internships (USGS) TNR: 1229 USGS K-12 programs BT: USGS educational services UF: K-12 programs (USGS) school programs (USGS) TNR: 1230 USGS laboratories BT: USGS facilities UF: laboratories (USGS) TNR: 1231 USGS libraries and archives BT: USGS information services RT: datasets USGS search services UF: archives (USGS) data archives (USGS) libraries (USGS) TNR: 1232 USGS lifelong learning programs BT: USGS educational services UF: community education (USGS) continuing education (USGS) informal education (USGS) life-long learning programs (USGS) lifelong learning programs (USGS) non-formal education (USGS) TNR: 1233 USGS mapping centers BT: USGS facilities RT: USGS map servers USGS maps on demand UF: mapping centers (USGS) TNR: 1235 USGS map servers BT: USGS information services RT: USGS mapping centers USGS maps on demand UF: interactive map servers (USGS) map servers (USGS) TNR: 1234 USGS maps on demand BT: USGS sales and distribution services RT: USGS map servers USGS mapping centers UF: maps on demand (USGS) TNR: 1236 USGS media relations BT: USGS information services UF: USGS press relations media relations (USGS) press relations (USGS) TNR: 1237 USGS meetings BT: USGS educational services NT: USGS colloquia USGS symposia USGS workshops RT: speeches and testimony UF: meetings (USGS) TNR: 1238 USGS news BT: USGS UF: new mapping projects (USGS) new projects (USGS) news (USGS) what's new (USGS) TNR: 1239 USGS nuclear reactors BT: USGS facilities UF: nuclear reactors (USGS) TNR: 1240 USGS observatories BT: USGS facilities UF: observatories (USGS) TNR: 1241 USGS offices BT: USGS organization TNR: 1242 USGS open houses BT: USGS exhibits and facility tours UF: open houses (USGS) TNR: 1243 USGS organization BT: USGS NT: USGS disciplines USGS offices USGS partnerships USGS regional organization USGS teams TNR: 1244 USGS partnerships BT: USGS organization RT: USGS cooperative research & development agreements (CRADAs) UF: business partners (USGS) cooperative research (USGS) cooperators (USGS) partnerships (USGS) TNR: 1245 USGS personnel BT: USGS NT: USGS employment and volunteer opportunities UF: personnel (USGS) TNR: 1246 USGS policies and regulations BT: USGS RT: policies and regulations UF: policies (USGS) regulations (USGS) TNR: 1247 USGS press relations USE: USGS media relations USGS product support BT: USGS customer support and user feedback UF: product support (USGS) TNR: 1249 USGS programs BT: USGS NT: USGS interagency programs USGS international programs USGS science programs USGS standards development UF: programs (USGS) TNR: 1250 USGS publication servers BT: USGS information services UF: publication servers (USGS) TNR: 1251 USGS regional organization BT: USGS organization TNR: 1252 USGS sales and distribution services BT: USGS information services NT: USGS maps on demand RT: USGS Earth Science Information Centers (ESICs) UF: distribution services (USGS) map sales (USGS) ordering services (USGS) price lists (USGS) pricing and ordering (USGS) sales services (USGS) TNR: 1253 USGS science centers BT: USGS facilities UF: science centers (USGS) TNR: 1254 USGS science programs BT: USGS programs UF: science programs (USGS) TNR: 1255 USGS search services BT: USGS information services RT: USGS clearinghouses USGS libraries and archives UF: search services (USGS) TNR: 1256 USGS standards development BT: USGS programs RT: standards UF: standards development (USGS) TNR: 1257 USGS symposia BT: USGS meetings UF: symposia (USGS) TNR: 1258 USGS teams BT: USGS organization TNR: 1259 USGS technical support BT: USGS customer support and user feedback UF: technical support (USGS) TNR: 1260 USGS technology transfer BT: USGS contracts and grants UF: technology transfer (USGS) TNR: 1261 USGS user services BT: USGS NT: USGS customer support and user feedback USGS educational services USGS exhibits and facility tours USGS information services RT: USGS visitor centers UF: user services (USGS) SN: The user services facet contains terms to describe types of services provided by the USGS. For the most part, these are generic terms and not the names of specific services. TNR: 1262 USGS visitor centers BT: USGS facilities RT: USGS user services UF: visitor centers (USGS) TNR: 1263 USGS workshops BT: USGS meetings UF: workshops (USGS) TNR: 1264 Uub USE: ununnubium Uun USE: ununnunium Uuu USE: ununnilium V USE: vanadium vadose zone USE: unsaturated zone vanadium BT: chemical elements RT: metal elements UF: V SN: Metal element with symbol V and atomic number 23 TNR: 1610 vascular plants BT: plants (organisms) NT: ferns and fern allies flowering plants gymnosperms RT: botany SN: Plants which have a specialized conductive system. Includes xylem and phloem: club mosses, ferns, cycads, gymnosperms, and angiosperms. TNR: 1265 vegetation BT: organism groupings (non-taxonomic) NT: periphyton weeds aquatic vegetation RT: botany ecology plants (organisms) UF: grasses trees dendroecology SN: Plant life or general plant cover in an area. TNR: 1266 Vendian USE: Ediacaran vertebrate paleontology BT: paleontology RT: dinosaurs vertebrates SN: Branch of paleontology dealing with fossil animals that have spinal columns. TNR: 1267 vertebrates BT: animals NT: amphibians birds fish mammals reptiles RT: vertebrate paleontology vertebrate zoology SN: Animals possessing a vertebral column or backbone including birds, fishes, amphibians, reptiles, and mammals. TNR: 1269 vertebrate zoology BT: zoology NT: herpetology ichthyology mammalogy ornithology RT: game species vertebrates SN: Branch of zoology that deals with animals that have spinal columns. TNR: 1268 vertical datums USE: map coordinate systems videography BT: methods RT: photography remote sensing video monitoring SN: The process of recording and editing analog or digital video. TNR: 1276 video monitoring BT: field inventory and monitoring RT: videography UF: remote video monitoring SN: Field study employing the use of filming or repeated photography with stationary optical or digital cameras to observe changes in a feature or organism. TNR: 1273 videos BT: product types SN: Animation or other motion pictures, including videotape and DVD products. TNR: 1350 virology BT: microbiology RT: environmental health (human) viruses SN: Branch of biology dealing with viruses and viral diseases. TNR: 1279 viruses BT: organisms RT: virology SN: Very small particles visible only with an electronic microscope. Considered to be complex molecules and not living organisms, these are often causes of disease in plants, animals, and bacteria. TNR: 1280 visible light imaging BT: remote sensing RT: geography UF: satellite photography SN: Remote sensing methods using electromagnetic radiation which is visible to the human eye to react with the coating on a photographic plate or film. TNR: 1281 visitor centers (USGS) USE: USGS visitor centers visualization USE: visualization methods visualization methods BT: computational methods UF: visualization SN: The application of two-dimensional or three-dimensional graphical techniques for the analysis and interpretation of complex numerical data. TNR: 1284 vocalization methods BT: field inventory and monitoring RT: wildlife biology SN: Series of methods used to (a) record sonograms (sound spectrogram) of animal sounds which are analyzed to identify the presence of species in an area and to determine distinct sound patterns within a species, e.g., mating calls, danger alerts; (b) attract species to an area for inventory or monitoring by playing recorded animal sounds or mimicking them. TNR: 1285 volcanic activity BT: geologic processes NT: volcanic gas emission RT: hazards tectonic processes volcanology lahars aviation safety volcanic eruption prediction earthquakes UF: eruption lava flows pyroclastic flows volcanism volcano monitoring volcanic tremors SN: Episodes during which gases, ash, and lava (molten rock) escape from vents in the earth's crust, accompanied by minor tremors. TNR: 1286 volcanic ash USE: volcanic rocks volcanic eruption prediction BT: risk assessment RT: volcanic activity SN: Estimation of future volcanic activity using geological and geophysical observations. TNR: 1698 volcanic gas emission BT: volcanic activity UF: fumarolic activity SN: Emission of gases from fumaroles and volcanoes. TNR: 1358 volcanic rocks BT: igneous rocks UF: lava pyroclastic tuff volcanic ash SN: A generally finely crystalline or glassy igneous rock resulting from volcanic action at or near the earth's surface, either ejected explosively or extruded as lava. The term includes near-surface intrusions that form a part of the volcanic structure. TNR: 1340 volcanic tremors USE: volcanic activity volcanism USE: volcanic activity volcanology BT: geology RT: geothermal resources seismology tectonophysics tiltmeter measurement volcanic activity UF: vulcanology SN: The branch of geology that deals with volcanism and the processes involved in magma flow and eruption through a vent in the earth's surface. TNR: 1289 volcano monitoring US+: field inventory and monitoring volcanic activity volunteer opportunities (USGS) USE: USGS employment and volunteer opportunities vulcanology USE: volcanology W USE: tungsten wasps USE: bees and wasps waste repositories USE: waste treatment and disposal waste treatment USE: waste treatment and disposal waste treatment and disposal BT: human impacts RT: ecology mining hazards contamination and pollution social sciences wastewater use UF: nuclear waste repositories radioactive waste repositories sewage disposal waste repositories waste treatment wastewater treatment SN: The chemical and physical methods to recycle or dispose of materials which, without treatment, are deemed to have no further value or are too contaminated to be used. TNR: 1293 wastewater USE: wastewater use wastewater treatment USE: waste treatment and disposal wastewater use BT: instream water use RT: hydraulic engineering hydrology waste treatment and disposal UF: gray water grey water wastewater SN: Water that is reused after release from a wastewater treatment plant. TNR: 1295 water-quality USE: water quality water-quality data US+: water quality datasets water balance USE: water budget water birds USE: birds water budget BT: water supply and demand UF: water balance SN: An accounting of the inflow, outflow, and storage changes of water in a hydrologic unit. TNR: 1297 water chemistry BT: geochemistry NT: marine chemistry RT: ground-water quality nutrient content (water) oxygen content (water) salinity surface water quality suspended material (water) water hardness water pH water properties water quality water sampling water temperature SN: Branch of chemistry that deals with the elements and compounds in water. TNR: 1298 water circulation BT: hydrologic processes RT: atmospheric circulation hydrology ocean circulation streamflow UF: circulation (water) estuarine circulation estuarine currents lake circulation SN: The flow of water in a body of water due to wind or other forces or variations in density or temperature. Use 'water circulation' for situations that are not specifically covered by narrower terms. Use 'ocean circulation' for water circulation in the oceans. TNR: 1299 water cycle BT: hydrologic processes RT: evaporation precipitation (atmospheric) ground-water flow UF: hydrologic cycle recharge SN: Interchange of water among land, oceans, and atmosphere. TNR: 1360 water demand USE: water supply and demand waterfowl USE: birds water hardness BT: water properties RT: hydrology water chemistry UF: hardness (water) SN: Indicator of the concentration of alkaline salts in water, mainly calcium and magnesium, as a measure of water quality. TNR: 1301 water pH BT: water properties RT: hydrology water chemistry UF: pH (water) SN: The negative logarithm of the hydrogen ion concentration or activity of a water solution. Used for expressing both acidity (pH less than 7) and alkalinity (pH greater than 7), with 7 considered neutral. TNR: 1302 water pollution US+: water resources contamination and pollution water properties BT: topics NT: nutrient content (water) oxygen content (water) salinity suspended material (water) water hardness water pH water temperature dissolved gases RT: hydrology water chemistry water quality SN: Measurable physical and chemical characteristics of water from different sources. TNR: 1304 water properties (marine) USE: marine chemistry water quality BT: topics NT: ground-water quality marine water quality surface water quality RT: aquatic biology drinking water use hydrology water chemistry water properties contamination and pollution UF: dissolved constituents dissolved contaminants water-quality data water-quality SN: The chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose. TNR: 1306 water resource management BT: natural resource management RT: hydraulic engineering UF: artificial recharge impoundment reclaimed water SN: Methods of controlling or directing resources and activities related to water for a predetermined goal. TNR: 1307 water resources BT: natural resources NT: ground water surface water (non-marine) RT: hydrogeology hydrology limnology ocean characteristics UF: hydrosphere water pollution SN: Stocks of water, the liquid derived from precipitation. A constituent of living matter and necessity for all life, it covers a large proportion of the earth's surface. TNR: 1308 water sampling BT: field sampling RT: hydrology water chemistry SN: Methods of collecting a representative part of a body of water for testing in controlled conditions. TNR: 1309 watershed management BT: natural resource management RT: erosion floods streamflow SN: Controlling and directing the resources and activities associated with the land and streams of a drainage basin to maintain the supply and quality of water and prevent floods, erosions, and other destructive conditions. TNR: 1318 water subsurface USE: ground water water supply and demand BT: topics NT: water budget water use UF: water demand SN: The quantities of water resources in an area that are easily available and the amount of water that is needed for all uses. TNR: 1311 water table USE: ground-water level water temperature BT: water properties RT: hydrology water chemistry UF: temperature (water) SN: The degrees of heat of water from a given source at a specific time. TNR: 1312 water use BT: water supply and demand NT: instream water use offstream water use RT: hydraulic engineering hydrology UF: consumptive use (water) drawdown water utilities SN: Water withdrawal for a specific purpose, such as domestic use, irrigation, or industrial processing. TNR: 1313 water utilities USE: water use water waves USE: ocean waves weather USE: atmospheric and climatic processes weather monitoring US+: atmospheric and climatic processes field inventory and monitoring weather observations US+: atmospheric and climatic processes field inventory and monitoring weeds BT: vegetation SN: Plants whose presence in an area is undesirable. TNR: 1697 well drilling BT: natural resource extraction RT: drilling and coring SN: The process of artificial excavation for the purpose of withdrawing water, oil, or gas from underground. TNR: 1325 well logging USE: borehole logging wetland ecosystems BT: ecosystems RT: wetland functions aquatic biology ecology terrestrial ecosystems UF: marsh ecosystems marshland ecosystems riparian ecosystems SN: Ecosystems whose soil is saturated for long periods seasonally or continuously, including marshes, swamps, and ephemeral ponds. More detailed terms for wetlands can be selected from the FGDC Wetland Classification . TNR: 1326 wetland functions BT: ecosystem functions RT: wetland ecosystems ecology hydrology SN: Processes related to wetlands such as support of ecosystems, evaporation effects on weather, nutrient cycles, etc. TNR: 1327 whaling BT: marine fishery resources RT: marine biology SN: Taking whales from the ocean for marketing or subsistence purposes. TNR: 1328 what's new (USGS) USE: USGS news wildfires USE: fires wildlife BT: organism groupings (non-taxonomic) RT: animals wildlife biology SN: Undomesticated organisms living in natural settings without dependence on man. TNR: 1331 wildlife biology BT: zoology RT: animal tracking game management game species overfishing parasitology vocalization methods wildlife wildlife population management SN: Branch of biology dealing with living organisms, usually mammals, birds, or fishes, that are not domesticated or dependent on man. TNR: 1332 wildlife population management BT: biological population management NT: game management RT: biogeography wildlife biology SN: Monitoring and control of wildlife as a sustainable natural asset. TNR: 1333 wilson cycle USE: tectonic processes wind BT: atmospheric and climatic processes UF: wind erosion SN: Local air movements. TNR: 1690 wind erosion US+: erosion wind winter BT: seasons TNR: 1666 workshop reports USE: reports workshops (USGS) USE: USGS workshops worms BT: invertebrates NT: flatworms roundworms segmented worms RT: invertebrate zoology SN: Invertebrate animals of the phyla Annelida, Nematoda, Memertea, or Plathyhelminthes, that have long thin rounded or flat bodies without obvious appendages. TNR: 1336 x-ray diffraction BT: chemical analysis RT: mineralogy SN: Study of crystals which uses short wave electromagnetic radiations (x-rays). The xrays, scattered by the crystal atoms, show a characteristic interference pattern that is dependent upon the structure of the crystal. TNR: 1337 Xe USE: xenon xenon BT: chemical elements RT: noble gas elements UF: Xe SN: Noble gas element with symbol Xe and atomic number 54 TNR: 1613 Y USE: yttrium Yb USE: ytterbium yearbooks USE: reports ytterbium BT: chemical elements RT: lanthanide series elements UF: Yb SN: Rare earth (lanthanide series) element with symbol Yb and atomic number 70 TNR: 1616 yttrium BT: chemical elements RT: metal elements UF: Y SN: Metal element with symbol Y and atomic number 39 TNR: 1617 zinc BT: chemical elements RT: metal elements UF: Zn SN: Metal element with symbol Zn and atomic number 30 TNR: 1618 zirconium BT: chemical elements RT: metal elements UF: Zr SN: Metal element with symbol Zr and atomic number 40 TNR: 1619 Zn USE: zinc zoology BT: life sciences NT: invertebrate zoology vertebrate zoology wildlife biology RT: animals capturing (animals) carnivores consumers (organisms) herbivores migratory species omnivores pollinators UF: malacology SN: Branch of biology that deals with the reproduction, development and growth, anatomy, physiology, and behavior of animals. TNR: 1339 zooplankton USE: plankton Zr USE: zirconium