Alphabetical listing of categories: O

oblasts -> political areas (1) field observation -> field inventory and monitoring (324) indicator species observation -> ecosystem monitoring (72) weather observations (40) -> field inventory and monitoring WITH atmospheric and climatic processes observation sites -> research areas (3) observatories -> research facilities (2) radio observatories -> research facilities (2) observatorios -> research facilities (2) earthquake occurrence maps (12) -> earthquake occurrences WITH maps and atlases earthquake occurrences (39) ocean-atmosphere interaction (7) ocean bottom characteristics -> sea-floor characteristics (36) ocean characteristics (52) ocean chemistry -> marine chemistry (1) ocean circulation (2) ocean current measurement (1) -> field inventory and monitoring WITH ocean currents ocean currents (4) ocean currents (1) ocean floor features -> seafloor features (10) oceanic lithosphere (4) ocean monitoring (29) -> field inventory and monitoring WITH ocean characteristics biological oceanography -> marine biology (15) chemical oceanography -> marine chemistry (1) geological oceanography -> marine geology (35) oceanography -> ocean sciences (34) physical oceanography -> ocean sciences (34) ocean processes (16) ocean regions (1) oceans (4) oceans (6) -> ocean characteristics WITH ocean processes ocean salinity (2) ocean sciences (34) ocean temperature (5) ocean tides -> tides (oceanic) (3) ocean water quality -> marine water quality (11) ocean waves (7) distribution of animals -> biogeography (65) off-stream water use -> offstream water use (11) offices -> buildings (4) offshore areas -> coastal zones (43) offstream water use (11) distribution of plants -> biogeography (65) distribution of species -> biogeography (65) collection of specimens -> specimen collecting (9) bodies of water -> hydrographic features (165) sounds (bodies of water) -> channels (2) oil palm plantations -> agricultural sites (3) oil resources (20) oil wells -> wells (10) olive groves -> woods (1) ontogeny -> organism growth and development (9) open pit mines -> mine sites (7) optical backscatterance sensing -> optical methods (3) optically-stimulated luminescence dating -> luminescence dating (3) optical methods (3) optical microscopy (1) optical reflectance measurement -> optical methods (3) orchards -> agricultural sites (3) countries, 2nd order divisions (1) ore deposits (metallic) -> metallic ores (9) ore deposits (non-metallic) -> nonmetallic mineral resources (5) gold ores (2) metallic ores (9) organic decomposition -> biogeochemical cycling (9) organism groupings (non-taxonomic) (149) organism growth and development (9) biological organisms -> organisms (229) organisms (229) orienteering -> geolocation measurement (34) ornithology (29) orthoimagery (19) -> aerial photography WITH image collections orthophotographs (19) -> aerial photography WITH image collections ostracodes (1) outer core (earth) (1) outfall -> contamination and pollution (108) over-fishing -> overfishing (3) over-grazing -> overgrazing (1) overfalls -> hydrographic features (165) overfishing (3) overgrazing (1) overpasses -> bridges (2) intermittent oxbow lakes -> lakes (25) oxbow lakes -> lakes (25) dissolved oxygen -> oxygen content (water) (9) oxygen content (water) (9) oxygen isotope analysis (2) ozone layer (1) ozonesphere -> ozone layer (1)

Alphabetical index of categories: O