ASSEL, R. A. Classification of annual Great Lakes ice cycles: Winters
of 1973-2002. Journal of Climate 18:4895-4905 (2005). http://www.glerl.noaa.gov/pubs/fulltext/2005/20050028.pdf
Annual seasonal average ice cover from 1973 to 2002 and associated
dates of first ice, last ice, and ice duration are presented and discussed.
The annual seasonal average ice cover of each Great Lake is used to
define three ice cycle classes: mild, typical, and severe. About half
of the severe ice cycles occurred from 1977 to 1982 and about half of
the mild ice cycles occurred from 1998 to 2002. The seasonal progression
of daily lake-averaged ice cover, spatial differences in ice cover,
and differences among the Great Lakes for mild, typical, and severe
ice cycles are discussed within the context of lake bathymetry and winter
air temperatures. Seasonal average ice cover is larger on Lakes Superior,
Erie, and Huron relative to Lakes Michigan and Ontario, because of shallower
depths (for Erie and Huron) and lower air temperatures (for Superior)
relative to Lakes Michigan and Ontario. This ice cycle classification
scheme can be used to compare future Great Lakes ice cycle severity
with this 30-winter benchmark.
ASSEL, R. A. Detroit River - Western Lake Erie Basin Indicator Project.
Indicator: Lake Erie Ice Cover. U.S. EPA Web Site, pp. (2006). http://www.epa.gov/med/grosseile_site/indicators/index.htm
No abstract
Barbiero, R. P., T. F. NALEPA, and M. L. Tuchman. Phytoplankton, zooplankton,
and benthos. In The State of Lake Huron in 1999. M.P. Ebener (Ed.).
Special Publication 05-02. Great Lakes Fishery Commission, Ann Arbor,
MI, 33-41 (2005). http://www.glerl.noaa.gov/pubs/fulltext/2005/20050029.pdf
No specific FCOs for phytoplankton, zooplankton, and benthos exist. However,
FCOs call for balancing predator abundance with prey-fish production,
which is a function of plankton and benthos production. The Great Lakes
National Program Office (GLNPO) of the U.S. Environmental Protection
Agency has conducted regular surveillance monitoring of Lake Huron since
1983. The monitoring effort is focused on whole-lake responses to changes
in loadings of anthropogenic substances, so sampling is restricted largely
to the relatively homogeneous offshore waters. Data presented in this
report are for phytoplankton and zooplankton communities sampled at
14 sites lakewide during spring (20-21 April) and summer (15-17 August),
1999. Sampling methods and limnological conditions during the surveys
are described in Barbiero and Tuchman (2001) and Barbiero et al. (2001).
The description of the benthos community is consolidated from a variety
of unrelated studies.
Biddanda, B. A., D. F. Coleman, T. H. JOHENGEN, S. A. RUBERG, G. A.
Meadows, H. W. VanSumeren, R. R. Rediske, and S. T. Kendall. Exploration
of a submerged sinkhole ecosystem in Lake Michigan. Ecosystems
9:828-842 (2006). http://www.springerlink.com/content/r106152q530xn0m1
http://www.glerl.noaa.gov/pubs/fulltext/2006/20060020.pdf
Dissolution of the Silurian-Devonian aquifer in the Lake Huron Basin has
produced several karst formations in the bedrock (sinkholes), through
which groundwater emerges onto the lake floor. During September 2003,
we explored a recently discovered submerged sinkhole ecosystem (55 m
* 40 m * ~1 m) located at a depth of 93 m with a remotely operated vehicle
(ROV) equipped with a conductivity-temperature-depth (CTD) system, an
acoustic navigational system, a video camera, and a water sampling system.
In addition to two morphotypes of benthic mats, a 1–2 m thick
visibly cloudy near-bottom nepheloid-like layer (sinkhole plume) with
a strong hydrogen sulfide odor prevailed just above the seepage area
of clear water. Relative to lake water, water samples collected within
the sinkhole plume were characterized by slightly higher (by 4°C)
temperatures, very high levels of chloride (up to 175 mg l-1) and conductivity
(1,700 µS cm-1), as well as extremely high concentrations of sulfate
(1,400 mg l-1), phosphorus (3 mg l-1) and particulate organic matter
(400 mg C l-1). Compared to background lake water, sinkhole plume water
was characterized by approximately twofold lower C:N ratios and tenfold
higher levels of dissolved organic carbon, bacterial biomass as well
as heterotrophic bacterial production. Significant uptake of 14C-bicarbonate
in dark incubations provided preliminary evidence for occurrence of
chemosynthesis, possibly mediated by specialized Bacteria and Archea
present in this submerged sinkhole ecosystem in the Laurentian Great
Lakes.
BRANDT, S. B., J. Hendee, P. Levin, J. Phinney, D. Schuerer, and F.
Schwing. Ecological forecasting. White Paper #5. In Ecosystem Science
Capabilities Required to Support NOAA's Mission in the Year 2020.
NOAA Technical Memorandum NMFS-F/SPO-74. S.A. Murawski and G.C. Matlock
(Eds.). NOAA, National Marine Fisheries Service, Silver Spring, MD,
52-63 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/2006tm74.pdf
The health of the U.S. economy is inextricably linked to the health
of our Nation’s ecosystems and the goods and services they deliver
to our economy. Each year, U.S. ecosystems provide over $227 billion
in added value to the U.S. economy (CENR, 2001) as well as other harder-to-quantify
services and benefits such as waste detoxification and decomposition,
air and water purification, maintenance of biological diversity, and
recreational and spiritual renewal (Daily et al., 1997). Coastal ecosystems,
in particular, provide a wealth of fisheries resources and recreational
benefits, and are a potential source of life saving pharmaceuticals.
These important ecosystems can also directly impact human health from
exposure to contaminated water (e.g., from urban and agricultural runoff,
pollutants, coliform, and other pathogens, and toxic algae) or contaminated
food (e.g., fish and shellfish).
Bundy, M. H., H. A. VANDERPLOEG, P. J. Lavrentyev, and P. A. Kovalcik.
The importance of microzooplankton versus phytoplankton to copepod populations
during late winter and early spring in Lake Michigan. Canadian Journal
of Fisheries and Aquatic Sciences 62:2371-2385 (2005). http://www.glerl.noaa.gov/pubs/fulltext/2005/20050024.pdf
Feeding rates of the calanoid copepod Leptodiaptomus sicilis on natural assemblages
of phytoplankton and microzooplankton were evaluated during late winter
and early spring in Lake Michigan. Microzooplankton were the preferred
food source for this copepod, and larger size fractions of phytoplankton
were preferred to smaller size fractions. Ingestion rates of total chlorophyll
a ranged from 2 to 14 ng·copepod–1·day–1,
while ingestion rates of microzooplankton biomass ranged from 0.04 to
0.15 µg C·copepod–1·day–1. In these
experiments, microzooplankton carbon accounted for 22%–74% of
the total carbon ingested. Clearance rates of microzooplankton carbon
were positively related to the larger size fractions of chlorophyll
a and to total suspended solids. Measured ingestion rates of microzooplankton
and phytoplankton carbon suggest that calanoid copepod populations have
the potential to control microzooplankton production in late winter
and early spring, and even with an abundance of phytoplankton carbon,
food availability may limit the reproduction of L. sicilis. Because
microzooplankton contribute significantly to the diet of these copepods,
stimulation of the microbial food web by terrigenous inputs of nutrients
and carbon may be transmitted to higher trophic levels (i.e., mesozooplankton
and their predators) through heterotrophic flagellates and protozoans.
Bunnell, D. B., C. P. Madenjian, and T. E. CROLEY II. Long-term trends
of bloater (Coregonus hoyi) recruitment in Lake Michigan: evidence for
the effect of sex ratio. Canadian Journal of Fisheries and Aquatic
Sciences 63:832-844 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060005.pdf
Long-term population trends are generally explained by factors extrinsic
(e.g., climate, predation) rather than intrinsic (e.g., genetics, maternal
effects) to the population. We sought to understand the long-term population
dynamics of an important native Lake Michigan prey fish, the bloater
Coregonus hoyi. Over a 38-year time series, three 10- to 15-year phases
occurred (poor, excellent, and then poor recruitment) without high interannual
variability within a particular phase. We used dynamic linear models
to determine whether extrinsic (winter and spring temperature, alewife
predator densities) or intrinsic factors (population egg production,
adult condition, adult sex ratio) explained variation in recruitment.
Models that included population egg production, sex ratio, winter and
spring temperature, and adult bloater condition explained the most variation.
Of these variables, sex ratio, which ranged from 47% to 97% female across
the time series, consistently had the greatest effect: recruitment declined
with female predominance. Including biomass of adult alewife predators
in the models did not explain additional variation. Overall our results
indicated that bloater recruitment is linked to its sex ratio, but understanding
the underlying mechanisms will require additional efforts.
Cardenas, M. P., D. J. SCHWAB, B. J. EADIE, N. HAWLEY, and B. M. Lesht.
Sediment transport model validation in Lake Michigan. Journal of
Great Lakes Research 31:373-385 (2005). http://www.glerl.noaa.gov/pubs/fulltext/2005/20050031.pdf
A multiple sediment type, three-dimensional hydrodynamic and sediment
transport model was applied to Lake Michigan to simulate conditions
during the Spring 2000 resuspension event. Model predictions were compared
to data gathered by the EEGLE project including turbidity and downward
mass flux. The model predictions for turbidity compared well to observed
data, especially in capturing the distinctive peaks in turbidity due
to advection that occurred in the area of the resuspension feature.
The advection peaks seemed tied to the presence of a highly-resuspendable
pool of sediments that was transported by weaker winds during early
Spring 2000. The model predictions at depths of 40 m in the area of
the resuspension feature were more problematic, as the observed data
in one location showed a significant turbidity peak at the time of maximum
winds. The model underestimated turbidity at that particular location,
yet model predictions of a very similar turbidity peak were seen at
a similar depth. The different turbidity predictions at these locations
were due to underestimation of offshore flow by the hydrodynamic model.
The model generally underestimated downward mass flux, though the predictions
for the time-intervals that included the time of peak winds and the
following week were good to excellent. These intervals generally showed
the highest downward mass flux. This work highlights the importance
of multiple sediment types, their associated critical shear stresses
for resuspension, and the presence of a very easily resuspendable sediment
layer. The availability of comprehensive data set was also important.
Carter, G., P. Restrepo, J. Hameedi, P. Ortner, C. E. SELLINGER, J.
Stein, and T. Beechie. Freshwater issues. White Paper #3. In Ecosystem
Science Capabilities Required to Support NOAA's Mission in the Year
2020. NOAA Technical Memorandum NMFS-F/SPO-74. S.A. Murawski and
G.C. Matlock (Eds.). NOAA, National Marine Fisheries Service, Silver
Spring, MD, 29-39 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/2006tm74.pdf
Freshwater is our most precious and finite natural resource -- the
total amount of freshwater in lakes, streams, rivers, and groundwater
accounts for less than one percent of water on the Earth. As human populations
increase, so does competition for water to meet societal needs versus
to maintain the needs of the earth’s biological systems. Additionally,
there are increasing demands for recreational use of water in streams,
river, and lakes, and increasing awareness of interacting hydrological
ecological, and social systems required for a healthy environment, dynamic
economy, and equitable allocation and use of freshwater.
CARTER, G. S., T. F. NALEPA, and R. R. Rediske. Status and trends
of benthic populations in a coastal drowned river mouth lake of Lake
Michigan. Journal of Great Lakes Research 32:578-595 (2006).
http://www.glerl.noaa.gov/pubs/fulltext/2006/20060029.pdf
Muskegon Lake was designated an Area of Concern because of severe environmental
impairments from direct discharge of industrial and municipal wastes.
Since diversion of all municipal and industrial wastewater in 1973,
few studies have assessed ecological changes associated with improved
water quality. We examined distributions and long-term changes in the
benthic macroinvertebrate community at 27 sites. Distributions were
evaluated relative to distance from the river mouth, water depth, grain
size, and known areas of sediment contamination. Temporal changes were
assessed relative to wastewater diversion. Oligochaeta and Chironomidae
dominated the community, and the oligochaete trophic condition index
indicated that, in 1999, the lake was generally mesotrophic to eutrophic.
Cluster analysis resulted in four distinct site groupings. A cluster
of sites near the river mouth had the highest total density (9,375 m–2)
and lowest diversity (Shannon Weaver Index 1.05) suggesting an enriched
habitat. A site cluster in the south central region had the lowest oligochaete
density (2,782 m–2), lowest oligochaete trophic condition index
scores (1.00), and highest diversity (2.24), suggesting the best habitat.
The chironomid community in this site cluster was dominated by predatory
species, possibly resulting from high concentrations of heavy metals
at some sites. Densities of all major taxonomic groups increased significantly
between 1972 and 1999. Decreasing proportions of oligochaetes (0.85
to 0.68) and increasing diversity suggest improved environmental conditions
over this period. Evidence suggests that changes in Muskegon Lake’s
benthic community were more a result of wastewater diversion than Dreissena
invasion
Cowden, J. R., D. Watkins, and T. E. CROLEY II. Investigating urban
land use effects on runoff by using the distributed large basin runoff
model. Proceedings, The World Environmental and Water Resources Congress
2006: Examining the Confluence of Environmental and Water Concerns,
Omaha, Nebraska, May 21-25, 2006. Environmental Water Resources Institute,
American Society of Civil Engineers, 9 pp. (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060024.pdf
Urbanization is a growing trend world wide and presents many significant
challenges in watershed planning. Distributed operational hydrology
models can assist decision makers in understanding the effects of land
use and urban development policies on large watersheds, including runoff
quantity and quality. The National Oceanic and Atmospheric Administration’s
Great Lakes Environmental Research Laboratory (GLERL) has developed
the Distributed Large Basin Runoff Model (DLBRM) as a large-scale model
for the Great Lakes basin. This paper illustrates how the daily DLBRM
may be used to model runoff impacts of urbanization. Urbanization trends
within the Clinton watershed of Southeastern Michigan are discussed,
including analysis of stationary stream flow trends of the watershed.
Calibration issues regarding temporal parameter variability are also
addressed followed by urbanization scenario simulations within the Clinton
watershed
CROLEY, T. E., II. Modified Great Lakes hydrology modeling system
for considering simple extreme climates. NOAA Technical Memorandum GLERL-137.
NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI,
27 pp. (2006). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-137/tm-137
We (the Great Lakes Environmental Research Laboratory) want to simulate
Great Lakes hydrology for simple hypothetical climate scenarios to understand
the extremes necessary to cause closed (terminal) lakes, suspected to
have occurred about 7,900 radiocarbon years ago. We use our Advanced
Hydrologic Prediction System with some conditions estimated for this
period. We use dynamic lake areas (which vary with lake depth) to correct
modeled over-lake precipitation, runoff, and lake evaporation, and neglect
existing diversions and consumptions. We use simple shifts in precipitation,
air temperature, and humidity, relative to the present base climate,
with 52 years of daily historical meteorology. For steady-state analysis
of the interconnected Great Lakes, we employ lake outflow-depth rating
curves (using estimated sill elevations) reasonable for a natural system
and combine with a water balance for all the lakes connected by their
channels. We consider the upper and lower Great Lakes separately with
no river connection, as in the early Holocene basin configuration. We
identify candidate climates that result in closed lakes by looking at
lake outflows and levels, demonstrating that climate may have been the
mechanism creating terminal lake status in the past. The lakes would
close in the order: Erie, Superior, Michigan-Huron, and Ontario for
increasingly drier and warmer climates. For a temperature rise of T
ºC and a precipitation drop of P% relative to the present base climate,
conditions for complete lake closure range from 4.7 T + P > 51 for
Erie to 3.5 T + P > 71 for Ontario
CROLEY, T. E. II. Using climatic predictions in Great Lakes hydrologic
forecasts. In ASCE Task Committee Report on Climatic Variations,
Climate Change, and Water Resources Engineering. J. Garbrecht and T.
Piechota (Eds.) . American Society of Civil Engineers, Arlington, VA,
164-185 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060013.pdf
The Great Lakes Environmental Research Laboratory’s (GLERL’s)
Advanced Hydrologic Prediction System (AHPS) illustrates the technology
for those interested in using climate predictions in water resources
decisions. It provides 1-6-month probability outlooks for 25 hydrology
variables over the 121 watersheds and 7 lake surfaces of the Great Lakes
basin, including simultaneous water levels on all lakes. The system
incorporates both current conditions, antecedent to a forecast, and
multiagency, multi-area, multi-period climate outlooks of meteorology
probabilities. Extended water level forecasts are evaluated over three
periods to determine the value of antecedent conditions and meteorological
outlooks in making them. The suitability of GLERL’s AHPS forecasts
is also considered relative to existing US and Canadian forecasts. While
the use of antecedent conditions adds considerably to Great Lakes forecasting
ability, the use of existing meteorological outlooks adds little. GLERL’s
AHPS appears better than, or as good as, other Great Lakes forecasts
and offers the advantage of improvement as better near real time data
streams and improved process models become available. Forecasts that
utilize climate predictions are used in several water resource decision
settings, as illustrated here
CROLEY, T. E. II., and C. He. Watershed surface and subsurface spatial
intraflows model. Journal of Hydraulic Engineering 11(1):12-20
(2006).
We present new developments to the original, spatially lumped large
basin runoff model (LBRM) of the National Oceanic and Atmospheric Administration's
Great Lakes Environmental Research Laboratory. In addition to making
it a two-dimensional, spatially distributed model, we modify it to allow
muting flows between adjacent cells upper soil zones, lower soil zones,
and groundwater zones. We modify the LERM continuity equations for these
additional flows and add corresponding corrector terms to the original
solution equations. We derive the flow network from elevation and hydrography
and the LBRM automatically arranges eel) computations. We apply the
newly modified LBRM to the Kalamazoo River watershed in Michigan and
to the Maumee River watershed in Ohio. The simulations show that the
Kalamazoo River has dominant groundwater storage, allowing delayed and
sustained hydrologic responses to rainfall whereas the Maumee River
lacks any significant groundwater storage, allowing a fast flashy response
to rainfall. These results are characteristic of the study watersheds,
indicating that the addition of subsurface intraflows in the model has
improved watershed representation
DeMaster, D., M. Fogarty, D. M. MASON, G. Matlock, and A. Hollowed.
Management of living marine resources in an ecosystem context. White
paper #2. In Ecosystem Science Capabilities Required to Support
NOAA's Mission in the Year 2020. NOAA Technical Memorandum NMFS-F/SPO-74.
S.A. Murawski and G.C. Matlock (Eds.). NOAA, National Marine Fisheries
Service, Silver Spring, MD, 15-28 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/2006tm74.pdf
One of the four goals articulated in NOAA’s Strategic Plan is
to “protect, restore and manage coastal and ocean resources through
an ecosystem approach” (NOAA, 2004). This goal flows from the
mandates and direction of such Federal laws, executive orders, courts,
and international treaties as the Magnuson-Stevens Fishery and Conservation
Management Act (MSFCMA), Endangered Species Act (ESA), National Environmental
Policy Act (NEPA), Marine Mammal Protection Act, Coral Reef Conservation
Act, Coastal Zone Management Act, National Marine Sanctuaries Act, International
Commission for the Conservation of Atlantic Tunas, and Inter-American
Tropical Tuna Commission. These directives reflect society’s desire
for policies and institutions to manage the environment. When combined,
they reflect the recognition that fishing is but one competing use of
ecosystems that produces a broad set of ecological and societal benefits.
But the benefits are not achieved without costs; thus, there is a need
to manage LMRs in an ecosystem context. The critical need for a more
holistic approach to managing the use of LMRs has been well articulated
in a number of recent publications, including the U.S. Commission on
Ocean Policy report (USCOP, 2004), U.S. Ocean Action Plan (CEQ, 2004),
Pew Oceans Commission report (2003), Rappoport (1998), report to Congress
by the Ecosystem Principles Advisory Panel (1999), report by the United
Nations’ Food and Agriculture Organization (FAO, 2003), a series
of essays published by the Marine Ecology Progress Series (Browman and
Stergiou, 2004), and a series of National Research Council (NRC) publications
(1994, 1999b, 1999c, 2001, 2002), as well as numerous references contained
therein.
DYBLE, J., P. A. Tester, and R. W. Litaker. Effects of light intensity
on cylindrospermopsin production in the cyanobacterial HAB species Cylindrospermopsis
raciborskii. African Journal of Marine Science 28(2):309-312
(2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060025.pdf
The role of light intensity on growth and the production of the hepatotoxin
cylindrospermopsin (CYN) in the cyanobacterial harmful algal bloom species
Cylindrospermopsis raciborskii was investigated using cultured isolates
grown in N-free media under a series of neutral density screens. Maximum
growth as indicated by chlorophyll a concentrations was measured at
75 µmol photons m-2 s-1, whereas maximum intracellular and extracellular
CYN concentrations occurred in cultures grown under the highest light
intensity (140 µmol photons m-2 s-1). During exponential growth
phase, N-limited C. raciborskii cultures grown under light intensities
of 18–75 µmol photons m-2 s-1 exhibited a strong linear
relationship between light intensity and both intracellular and extracellular
CYN concentrations. Extracellular CYN concentrations increased significantly
as the culture moved from log to stationary growth phase. These results
indicate that the highest intracellular toxin concentrations in the
field are likely to occur in C. raciborskii populations that have been
actively growing at light intensities of 75–150 µmol photons
m-2 s-1 for more than two weeks, and that peak soluble toxin levels
will be found at the end of a bloom.
FOLEY, A. J. III, T. F. NALEPA, G. K. Walker, and M. J. McCORMICK.
Epibiont populations associated with Diporeia spp. (amphipoda) from
Lake Michigan. Verh. Internat. Verein. Limnol. 29:1205-1211
(2006).
The benthic amphipod Diporeia spp. is the dominant benthic macroinvertebrate
in the offshore region (>30 m) of the Laurentian Great Lakes and,
as a detritivore, plays a critical role in the offshore food web. Diporeia
feed on organic material that settles from the water column and, in
turn, are fed upon by many fish species. This organism, therefore, serves
as an important trophic link between lower and upper trophic levels
(Gardner et al. 1990). Diporeia are currently declining in all the Great
Lakes except Lake Superior (Dermott & Kerec 1997, Nalepa et al.
1998, Lozano et al. 2001, Dermott 2001). While declines have been coincidental
with the introduction and spread of the zebra mussel (Dreissena polymorpha)
and the quagga mussel (Dreissena bugensis), exact mechanisms for the
negative response have not been clearly defined (Nalepa et al. 2004).
Gregson, B. P., D. F. Millie, C. Cao, G. L. FAHNENSTIEL, R. J. Pigg,
and D. P. Fries. Simplified enrichment and identification of environmental
peptide toxins using antibody-capture surfaces with subsequent mass
spectrometry detection. Journal of Chromatography A 1123(2):233-238
(2006).
The development of a simplified assay for detection of congeners of
the microcystin (MC) hepatotoxin is described that combines the extreme
sensitivity of surface-enhanced laser desorption/ionization time-of-flight
MS (SELDI TOF-MS) with the superior selectivity of immunoaffinity interactions.
Using methods similar to those of conventional immunoassays, MC standards
were captured and enriched on immunoreactive ProteinChips coated with
an MC-antibody and analyzed by TOF-MS. Unlike with conventional immunoassays,
individual congeners were resolved from mixed pools. Assay conditions
were optimized for the quantification of MC from untreated raw pond
water at concentrations as low as 0.025 µg L-1, well below the
public health relevant guideline of 1 µg L-1.
HAWLEY, N., T. H. JOHENGEN, Y. R. Rao, S. A. RUBERG, D. BELETSKY,
S. A. LUDSIN, B. J. EADIE, D. J. SCHWAB, T. E. CROLEY II, and S. B.
BRANDT. Lake Erie hypoxia prompts Canada-U.S. study. EOS Transactions
86(32):313-319 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060021.pdf
Because of its size and geometry, the central basin of Lake Erie,
one of North America’s Great Lakes, is subject to periods in the
late summer when dissolved oxygen concentrations are low (hypoxia).
An apparent increase in the occurrence of these eutrophic conditions
and ‘dead zones’ in recent years has led to increased public
concern. The International Field Years for Lake Erie (IFYLE) project
of the Great Lakes Environmental Research Laboratory (GLERL, a U.S.
National Oceanic and Atmospheric Administration (NOAA) laboratory),
was established in 2005 in response to this increase. This project is
investigating the causes and consequences of hypoxia in the lake. As
part of the effort, scientists from the United States and Canada conducted
an extensive field study in 2005 to gather more information on the duration
and extent of the hypoxic zone and its effects on the biota in the lake.
This article gives a brief history and description of the problem and
presents initial results from the field study. Preliminary results from
2005 indicate that, when compared with data collected in the past 25
years, the hypoxic region was one of the largest (approximately 10,000
square kilometers) ever documented in the lake. This is about half the
maximum size of the hypoxic area in the Gulf of Mexico [Rabelais et
al., 1999] and about five times larger than the maximum hypoxic area
in the Chesapeake Bay [Hagy et al., 2004].
He, C., and T. E. CROLEY II. Spatially modeling nonpoint source pollution
loadings in the Saginaw Bay watersheds with the DLBRM. Geographic Information
Systems and Water Resources IV, AWRA Spring Specialty Conference, Houston,
TX, May 8-10, 2006. American Water Resources Association, 8 pp. (2006).
http://www.glerl.noaa.gov/pubs/fulltext/2006/20060023.pdf
Accurate nonpoint source (NPS) pollution accounting is essential to
effective water quality and ecosystem management. The National Oceanic
and Atmospheric Administration’s Great Lakes Environmental Research
Laboratory and Western Michigan University are jointly developing a
physically based, spatially-distributed hydrology model to simulate
spatial and temporal NPS material distributions in the Saginaw Bay watersheds,
draining into Georgian Bay in the Laurentian Great Lakes. Multiple databases
of meteorology, land use, topography, hydrography, soils, and agricultural
statistics were used to estimate nonpoint source loading potential in
the study watersheds. Animal manure production was computed from tabulations
of animals by zip code area for the census years of 1987, 1992, 1997,
and 2002. Relative chemical loadings for agricultural land use were
calculated from fertilizer and pesticide estimates by crop for the same
periods. These estimates are used as the input to the distributed water
quality model for simulating pollutant transport through surface and
subsurface processes to Great Lakes waters. Visualization and GIS interfaces
are developed to visualize the spatial and temporal distribution of
the pollutant transport. These simulations, once verified with the in
situ Saginaw Bay water quality data, will provide important information
to researchers and decision makers for developing the Environmental
Protection Agency (EPA) mandated Total Maximum Daily Load programs to
minimize the nonpoint source pollution in the watersheds
Hong, Y., A. Steinman, B. Biddanda, R. Rediske, and G. L. FAHNENSTIEL.
Note. Occurrence of the toxin-producing Cyanobacterium Cylindrospermopsis
raciborskii in Mona and Muskegon Lakes, Michigan. Journal of
Great Lakes Research 32:645-652 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060028.pdf
The bloom-forming and toxin-producing cyanobacterium Cylindrospermopsis
raciborskii was observed in Muskegon and Mona lakes, drowned river-mouth
tributaries of Lake Michigan. Morphological features of the taxon were
similar to those described elsewhere. The species was observed only
in late summer; elevated bottom water temperature, and perhaps phosphorus
concentration, appears to be implicated in its appearance. Maximum abundances
at any given site reached 393 and 0.9 trichomes/mL in Mona Lake and
Muskegon Lake, respectively. Although these concentrations are low relative
to other reports, the presence of this species in these two lakes from
adjacent watersheds adds to a growing body of literature that suggests
the distribution of C. raciborskii is on the increase in northern latitudes.
Hultquist, T. R., M. R. Dutter, and D. J. SCHWAB. Reexamination of
the 9-10 November 1975 Edmund Fitzgerald storm using today's technology.
Bulletin of the American Meteorological Society 87(5):607-622
(2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060016.pdf
An intense autumn storm moved through the upper Great Lakes region
on 10 November 1975, producing extremely hazardous wind and wave conditions
on Lake Superior. The storm is particularly memorable because it is
forever linked with the loss of the ship Edmund Fitzgerald (U.S. Coast
Guard 1977), which occurred at approximately 0015 UTC (7:15 P.M. EST)
11 November 1975. There are numerous theories about the specific cause
for the loss of the Edmund Fitzgerald, and this article makes no attempt
to further investigate possible causes, but rather focuses on determining
the most likely weather conditions throughout the storm. Meteorological
observations from the storm were combined with modern numerical weather
prediction models to provide detailed hindcasts of conditions throughout
the storm. These hindcasts indicate that although severe wind and wave
conditions did occur during the storm, the most extreme conditions were
confined to a 6-h period in the late afternoon and early evening of
10 November 1975, during which time the Edmund Fitzgerald sank.
JAEGAR, A. L. Invasive species impacts on ecosystem structure and
function. Master's Thesis. Michigan State University, Department of
Fisheries and Wildlife, E. Lansing, MI, 210 pp. (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060022.pdf
Exotic species invasion is a worldwide threat to the integrity of
aquatic ecosystems. To understand ecosystem level response to the introduction
of exotic species, I compared food web characteristics of two eutrophic
Great Lakes ecosystems - the Bay of Quinte, Lake Ontario, Canada, and
Oneida Lake, New York, USA - before and after zebra mussel (Dreissena
polymorpha) invasion using ecological network analysis (ENA) and a social
network analysis method, cohesion analysis (CA). ENA quantifies ecosystem
function through an analysis of food web transfers, while CA assesses
ecosystem structure by organizing food web members into subgroups of
strongly interacting predators and prey. In Oneida Lake and the Bay
of Quinte, zebra mussel invasion increased food web organization and
the potential for system development. Additionally, zebra mussel invasion
stimulated benthic production in both systems. Effects on food web structure
were strongest in the Bay of Quinte where zebra mussel invasion removed
subgroup structure entirely. In Oneida Lake, over 33% of taxa changed
subgroup association after invasion, with benthically associated subgroups
gaining the most members. This analysis suggested that the effects of
zebra mussel introduction are similar in ecosystems of comparable trophic
status and that future invasions of eutrophic systems could have similar
impacts on ecosystem structure and function.
JOSEPH, S. Beach closures and human health. NOAA, Great Lakes Environmental
Research Laboratory, Ann Arbor, MI, 2 pp. (2006). http://www.glerl.noaa.gov/pubs/brochures/beachclosures.pdf
During natural and human-made events, pollutants enter into the Great
Lakes that pose a health risk to swimmers, boaters, and other recreationists.
Microscopic pollutants, such as bacteria and viruses can be pathogenic
(cause illness in humans). The symptoms and illnesses that these pathogens
can cause vary based on multiple factors. Some people might get a sore
throat or cold-like symptoms, others can get gastroenteritis (diarrhea).
Usually the elderly, people with compromised immune systems, and young
children are more at risk of illness from disease causing bacteria in
the water. In order to protect people from getting sick your county,
tribal, or state health department monitors the quality of Great Lakes
beaches. There are two main bacteria, E.coli and Enterococci, that are
monitored in recreational water. If the level of either bacteria is
too high, they will close the beach until the bacteria level decreases
LEE, J. H., and P. F. LANDRUM. Development of a Multi-component Damage
Assessment Model (MDAM) for time-dependent mixture toxicity with toxicokinetic
interactions. Environmental Science and Technology 40(4):1341-1349
(2006).
A new mixture toxicity model was developed to predict the time-dependent
toxicity of a mixture with toxicokinetic interactions directed specifically
toward addressing biotransformation. The Damage Assessment Model (DAM),
a toxicokinetic-toxicodynamic model that describes and predicts the
time-dependent toxicity of a single compound, was extended to a multicomponent
model for mixture toxicity. The model assumes that cumulative damage
from the parent compound, metabolites, and/or a biotransformation inhibitor
are additive, and the sum of the cumulative damage determines mixture
toxicity. Since incorporation of the damage addition hypothesis into
the DAM was equivalent to an independent action model for mixture toxicity,
it was applied to describe the combined effect of mixture components
with potentially dissimilar modes of action. From the multicomponent
DAM, a time-dependent toxic unit model was derived and applied to determine
the toxic units of mixture components. This model suggests a series
of experimental designs required to assess the role of biotransformation
in the toxicity of metabolized organic compounds and a data analysis
method to separately estimate toxicodynamic parameters for the parent
compound and metabolites.
LEE, J. H., and P. F. LANDRUM. Application of a Multi-component Damage
Assessment Model (MDAM) for the toxicity of metabolized PAH in Hyalella
azteca. Environmental Science and Technology 40(4):1350-1357 (2006).
Biotransformation and time-dependent toxicity of pyrene and fluorene,
in the presence and absence of the biotransformation inhibitor 6-propylpiperonyl
butyl diethylene glycol ether known as piperonyl butoxide (PBO), were
investigated in Hyalella azteca. Toxicokinetics and biotransformation
were determined in both short- and longterm experiments. For pyrene,
the uptake rate coefficient (ku = 99 +- 9 L kg-1 h-1), elimination rate
constant for parent compound (kep = 0.050 +- 0.008 h-1), biotransformation
rate constant (km = 0.016 +- 0.003 h-1), and elimination rate constant
for metabolites (kem = 0.021 +- 0.007 h-1) were determined from a short-term
study. For fluorene, ku (130 +- 30 L kg-1 h-1) and kep (1.7 +- 0.2 h-1)
were estimated based on km (0.015 +- 0.002 h-1) and kem (0.011 +- 0.002
h-1) determined from a long-term study. At steady state, the percent
metabolites for pyrene and fluorene were 43% and 58%, respectively,
determined from km/( km+ kem). Time dependent toxicity was determined
as both lethal water concentration and lethal body residue in the presence
and absence of PBO. Co-exposure to PBO decreased the median lethal residue
(LBR50) for parent pyrene and shortened the median lethal time (LT50).
Pyrene toxicity was explained by the body residues of parent pyrene
and PBO, where the metabolites’ contribution was negligible. For
fluorene, coexposure to PBO increased the LBR50 for parent fluorene
and shortened the LT50. Thus, fluorene metabolites contributed significantly
to the toxicity. Using a multicomponent damage assessment model, the
toxicodynamic parameters, damage accrual rate coefficient, and damage
recovery rate constant for parent pyrene and parent fluorene were very
similar and estimated to be from 0.009 to 0.020 µmol-1 g h-1 and
from 0.003 to 0.013 h-1, respectively, and the incipient LBR50 at the
infinite time (LBR50(t = oo)) was from 0.24 to 0.46 µmol g-1,
respectively. These values are similar to the reported (LBR50(t = oo))
for other nonpolar narcotics such as pentachlorobenzene (PCBz, 0.38
(0.13 µmol g-1) and dichlorophenylchloroethylene (DDE, 0.41 +-
0.19 µmol g-1). For fluorene metabolites, these values were 0.10
+- 0.03 µmol-1 g h-1, 0.034 +- 0.021 h-1, and 0.33 +- 0.23 µmol
g-1, respectively. However, for pyrene metabolites, since toxicity of
pyrene metabolites was negligible, the parameters could not be estimated.
LIEBIG, J. R., H. A. VANDERPLOEG, and S. A. RUBERG. Factors affecting
the performance of the optical plankton counter in large lakes: insights
from Lake Michigan and laboratory studies. Journal of Geophysical
Research 111(C05S02):10 pp. (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060012.pdf
There has been a question as to whether the optical plankton counter
(OPC) accurately measures zooplankton density and biomass in large lakes,
oceans, and estuaries. Results from our Lake Michigan surveys in 1998–2000
often revealed poor agreement between the OPC-2T and 153-mm mesh plankton
net samples. The most serious common problem was overestimation of zooplankton
biomass by the OPC relative to net tows. Such overestimates have been
attributed to the orientation of zooplankton assuming that their maximal
silhouette area is detected by the OPC, coincidence, and the presence
of nonzooplankton particles. Experiments using an OPC-1L with polymer
microspheres, nylon rods, or live zooplankton confirmed that the OPC
accurately counts and sizes zooplankton at low zooplankton concentrations
typically found in Lake Michigan and that a shape factor correction
often used need not be applied. Most overestimation of biomass was associated
with the presence of nonzooplankton particles. Worst agreement was seen
in shallow nearshore zones during periods of high total suspended matter
(TSM), which consisted of fine sediments and large resuspended particles
such as sediment phytoplankton aggregates, and benthic plant and animal
debris. Best agreement was found under low TSM conditions associated
with offshore waters during the stratified period.
Lindberg, W. J., T. K. Frazer, K. P. Portier, F. Vose, J. Loftin,
D. J. Murie, D. M. MASON, B. Nagy, and M. K. Hart. Density-dependent
habitat selection and performance by a large mobile reef fish. Ecological
Applications 16(2):731-746 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060009.pdf
Many exploited reef fish are vulnerable to overfishing because they
concentrate over hard-bottom patchy habitats. How mobile reef fish use
patchy habitat, and the potential consequences on demographic parameters,
must be known for spatially explicit population dynamics modeling, for
discriminating essential fish habitat (EFH), and for effectively planning
conservation measures (e.g., marine protected areas, stock enhancement,
and artificial reefs). Gag, Mycteroperca microlepis, is an ecologically
and economically important warm-temperate grouper in the southeastern
United States, with behavioral and life history traits conducive to
large-scale field experiments. The Suwannee Regional Reef System (SRRS)
was built of standard habitat units (SHUs) in 1991–1993 to manipulate
and control habitat patchiness and intrinsic habitat quality, and thereby
test predictions from habitat selection theory. Colonization of the
SRRS by gag over the first six years showed significant interactions
of SHU size, spacing, and reef age; with trajectories modeled using
a quadratic function for closely spaced SHUs (25 m) and a linear model
for widely spaced SHUs (225 m), with larger SHUs (16 standardized cubes)
accumulating significantly more gag faster than smaller 4-cube SHUs
(mean1/72.5 gag/16-cube SHU at 225-m spacing by year 6, compared to
24.2 gag/4-cube SHU for same spacing and reef age). Residency times
(mean 1/4 9.8 mo), indicative of choice and measured by ultrasonic telemetry
(1995–1998), showed significant interaction of SHU size and spacing
consistent with colonization trajectories. Average relative weight (Wr)
and incremental growth were greater on smaller than larger SHUs (mean
Wr 1/4 104.2 vs. 97.7; incremental growth differed by 15%), contrary
to patterns of abundance and residency. Experimental manipulation of
shelter on a subset of SRRS sites (2000–2001) confirmed our hypothesis
that shelter limits local densities of gag, which, in turn, regulates
their growth and condition. Density-dependent habitat selection for
shelter and individual growth dynamics were therefore interdependent
ecological processes that help to explain how patchy reef habitat sustains
gag production. Moreover, gag selected shelter at the expense of maximizing
their growth. Thus, mobile reef fishes could experience density-dependent
effects on growth, survival, and/or reproduction (i.e., demographic
parameters) despite reduced stock sizes as a consequence of fishing.
Liu, L., M. S. Phanikumar, S. L. Molloy, R. L. Whitman, D. A. Shively,
M. B. Nevers, D. J. SCHWAB, and J. B. Rose. Modeling the transport and
inactivation of E. coli and Enterococci in the near-shore region
of Lake Michigan. Environmental Science and Technology 40(16):5022-5028
(2006).
To investigate the transport and fate of fecal pollution at Great
Lakes beaches and the health risks associated with swimming, the near-shore
waters of Lake Michigan and two tributaries discharging into it were
examined for bacterial indicators of human fecal pollution. The enterococcus
human fecal pollution marker, which targets a putative virulence factors
the enterococcal surface protein (esp) in Enterococcus faecium, was
detected in 2/28 samples (7%) in the tributaries draining into Lake
Michigan and in 6/30 samples (20%) in Lake Michigan beaches. This was
indicative of human fecal pollution being transported in the tributaries
and occurrence at Lake Michigan beaches. To understand the relative
importance of different processes influencing pollution transport and
inactivation, a finite-element model of surf-zone hydrodynamics (coupled
with models for temperature, E. coli and enterococci) was used. Enterococci
appear to survive longer than E. coli, which was described using an
overall first-order inactivation coefficient in the range 0.5-2.0 per
day. Our analysis suggests that the majority of fecal indicator bacteria
variation can be explained based on loadings from the tributaries. Sunlight
is a major contributor to inactivation in the surf-zone and the formulation
based on sunlight, temperature and sedimentation is preferred over the
first-order inactivation formulation.
LIU, P. C., K. R. MacHuchon, and C. H. Wu. Exploring rogue waves from
observations in South Indian Ocean. In Rogue Waves 2004. M. Olagnon
and M. Prevosto (Eds.). Ifremer, Brest, France, 1-10 (2004). http://www.glerl.noaa.gov/pubs/fulltext/2004/20040037.pdf
Amidst all the enticing advancements on rogue waves in recent years,
the conspicuous scarcity of actual, in situ, rogue wave measurements
still represents an inevitable hindrance shadowing over the horizon
of rogue wave studies. In this paper we wish to present an exploratory
observational study of rogue waves based on wave measurement made in
South Indian Ocean. As there have been significant theoretical advancements
in numerical simulation of rogue waves, the need for actual field observations
of rogue waves should certainly be commensurably supplemented. We hope
our efforts in this study can be ventured toward further understanding
of rogue waves in reality.
LIU, P. C., and K. R. MacHutchon. Are there different kinds of rogue
waves? Proceedings, 25th International Conference on Offshore Mechanics
and Arctic Engineering, Hamburg, Germany, June 4-9, 2006. ASME, 6 pp.
(2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060014.pdf
Inasmuch as there is as yet still no universally accepted definition
for rogue waves in the ocean, we think there might just be more than
one kind of rogue waves to contend with. While the conventional approach
has generally designated waves with Hmax/Hs greater than 2.2 as possible
rogue waves, based on Rayleigh distribution considerations, there is
conspicuously no provision as to how high the ratio of Hmax/Hs can be.
In our analysis of wave measurements made from a gas-drilling platform
in South Indian Ocean, offshore from Mossel Bay, South Africa, we found
a number of cases that indicated Hmax/Hs could be valued in the range
between 4 and 10. If this were to be the case then these records could
be considered to be "uncommon" rogue waves, whereas a record
of Hmax/Hs in the range between 2 and 4 could be considered to comprise
"typical" rogue waves. On the other hand the spikes in the
Hmax data could have been caused by equipment malfunction or some other
phenomenon. Clearly the question of whether or not there are different
kinds of rogue waves can not be readily answered by theoretical considerations
alone and there is a crucial need for long-term wave time series measurements
for studying rogue waves.
LUDSIN, S. A., B. J. Fryer, and J. E. Gagnon. Comparison of solution-based
versus laser ablation inductively coupled plasma mass spectrometry for
analysis of larval fish otolith microelemental composition. Transactions
of the American Fisheries Society 135:218-231 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060002.pdf
Otolith microchemistry has become a widely used tool for fisheries-based
research in marine systems. However, its application to systems without
well-defined juvenile nursery areas in which distinct otolith elemental
signatures can develop (i.e., most freshwater systems) remains limited.
In large part, this deficiency is due to unsuitable protocols for reliably
processing and analyzing small otoliths of larvae. Herein, we evaluate
the abilities of solution-based (SO) and laser ablation (LA) inductively
coupled plasma mass spectrometry (ICPMS) to quantify the otolith elemental
composition of larval yellow perch Perca flavescens captured in three
distinct spawning locations in Lake Erie (USA–Canada). Analysis
of otolith pairs by each technique demonstrated that both SO- and LA-ICPMS
could be used to reliably quantify the more abundant elements, such
as Sr and Ba. Magnesium and zinc, analyzed by use of both SO- and LA-ICPMS,
also met the criteria for inclusion in our analyses (i.e., the coefficients
of variation of standards were ,10.5%, and over 90% of samples were
above detection limits at a single location). Upon closer inspection
of the data, however, we found that estimates of Mg and Zn were only
reliable for LA-ICPMS. Estimates of these two elements using SO-ICPMS
were unrealistically high, probably owing to contamination during the
otolith dissolution and handling phases. We also found that LA-ICPMS
provided more precise estimates than did SO-ICPMS for nearly all elements
explored, but LA-ICPMS was somewhat limited by high limits of detection
for some elements. Despite these differences, both techniques could
accurately discriminate among larvae produced in different Lake Erie
spawning locations, primarily because of the significant variation in
Sr among larval otoliths. Ultimately, although both methods are appropriate
for analysis of otoliths from larvae, we recommend the use of LA-ICPMS
in future otolith microchemical applications involving larvae.
Madenjian, C. P., D. V. O'Connor, S. A. POTHOVEN, P. J. Schneeberger,
R. R. Rediske, J. P. O'Keefe, R. A. Bergstedt, R. L. Argyle, and S.
B. BRANDT. Evaluation of a Lake Whitefish bioenergetics model. Transactions
of the American Fisheries Society 135:61-75 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060001.pdf
We evaluated the Wisconsin bioenergetics model for lake whitefish Coregonus
clupeaformis in the laboratory and in the field. For the laboratory
evaluation, lake whitefish were fed rainbow smelt Osmerus mordax in
four laboratory tanks during a 133-d experiment. Based on a comparison
of bioenergetics model predictions of lake whitefish food consumption
and growth with observed consumption and growth, we concluded that the
bioenergetics model furnished significantly biased estimates of both
food consumption and growth. On average, the model overestimated consumption
by 61% and underestimated growth by 16%. The source of the bias was
probably an overestimation of the respiration rate. We therefore adjusted
the respiration component of the bioenergetics model to obtain a good
fit of the model to the observed consumption and growth in our laboratory
tanks. Based on the adjusted model, predictions of food consumption
over the 133-d period fell within 5% of observed consumption in three
of the four tanks and within 9% of observed consumption in the remaining
tank. We used polychlorinated biphenyls (PCBs) as a tracer to evaluate
model performance in the field. Based on our laboratory experiment,
the efficiency with which lake whitefish retained PCBs from their food
(g) was estimated at 0.45. We applied the bioenergetics model to Lake
Michigan lake whitefish and then used PCB determinations of both lake
whitefish and their prey from Lake Michigan to estimate g in the field.
Application of the original model to Lake Michigan lake whitefish yielded
a field estimate of 0.28, implying that the original formulation of
the model overestimated consumption in Lake Michigan by 61%. Application
of the bioenergetics model with the adjusted respiration component resulted
in a field g estimate of 0.56, implying that this revised model underestimated
consumption by 20%.
Madenjian, C. P., S. A. POTHOVEN, J. M. Dettmers, and J. D. Holuszko.
Changes in seasonal energy dynamics of alewife (Alosa pseudoharengus)
in Lake Michigan after invasion of dreissenid mussels. Canadian
Journal of Fisheries and Aquatic Sciences 63:891-902 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060004.pdf
The dreissenid mussel invasion of Lake Michigan during the 1990s has
been linked to a concomitant decrease in the abundance of the amphipod
Diporeia. We tracked the seasonal energy dynamics of alewife (Alosa
pseudoharengus) in Lake Michigan during 2002–2004 and compared
our findings with previously published results for years 1979–1981.
Adult alewife energy density exhibited a pronounced seasonal cycle during
both the pre-invasion and post-invasion periods, with energy density
in October or November nearly twice as high as that in early summer.
However, on average, adult alewife energy density was 23% lower during
the post-invasion period compared with the preinvasion period. This
significant decline in energy density was attributable to decreased
importance of Diporeia in adult alewife diet. In contrast, energy density
of juvenile alewives did not significantly differ between the pre-invasion
and post-invasion periods. To attain a weight of 8 kg by age 4, bioenergetics
modeling indicated that a Chinook salmon (Oncorhynchus tshawytscha)
in Lake Michigan would have to consume 22.1% more alewives during the
post-invasion period compared with the pre-invasion period.
Mantha, P. S., J. B. Rose, and S. JOSEPH. Water pollution studies
for the lower Grand River, MI. Michigan State University Dept. of Fisheries
and Wildlife, E. Lansing, MI, 2 pp. (2006).
Researchers at Michigan State University and the NOAA Center for Excellence
in Great Lakes and Human Health, in cooperation with Ottawa County,
are conducting water quality investigations in the lower Grand River
to better understand bacteria, parasite and virus pollution. In order
to characterize and further our understanding of the sources of pollution
and how the microorganisms are transported in the river, we are monitoring
the beaches and locations within the river. The ultimate goals are to
be able to predict impaired water quality events, to aid in decisions
on pollution prevention and to further the protection of the public
using the waterways and beaches
MASON, D. M., T. B. Johnson, C. J. Harvey, J. F. Kitchell, S. T. Schram,
C. R. Bronte, M. H. Hoff, S. J. LOZANO, A. S. Trebitz, D. R. Schreiner,
E. C. Lamon, and T. Hrabik. Hydroacoustic estimates of abundance and
spatial distribution of pelagic prey fishes in western Lake Superior.
Journal of Great Lakes Research 31:426-438 (2005). http://www.glerl.noaa.gov/pubs/fulltext/2005/20050026.pdf
Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) are a valuable
prey resource for the recovering lake trout (Salvelinus namaycush) in
Lake Superior. However, prey biomass may be insufficient to support
the current predator demand. In August 1997, we assessed the abundance
and spatial distribution of pelagic coregonines and rainbow smelt in
western Lake Superior by combining a 120 kHz split beam acoustics system
with midwater trawls. Coregonines comprised the majority of the midwater
trawl catches and the length distributions for trawl caught fish coincided
with estimated sizes of acoustic targets. Overall mean pelagic prey
fish biomass was 15.56 kg ha–1 with the greatest fish biomass
occurring in the Apostle Islands region (27.98 kg ha–1), followed
by the Duluth Minnesota region (20.22 kg ha–1), and with the lowest
biomass occurring in the open waters of western Lake Superior (9.46
kg ha–1). Biomass estimates from hydroacoustics were typically
2–134 times greater than estimates derived from spring bottom
trawl surveys. Prey fish biomass for Lake Superior is about order of
magnitude less than acoustic estimates for Lakes Michigan and Ontario.
Discrepancies observed between bioenergetics-based estimates of predator
consumption of coregonines and earlier coregonine biomass estimates
may be accounted for by our hydroacoustic estimates.
McCORMICK, M. J., T. O. Manley, A. J. FOLEY III, J. C. Gascard, and
G. L. FAHNENSTIEL. Lake Champlain Lagrangian experiment. Verh. Internat.
Verein. Limnol. 29:1683-1687 (2006).
Lake Champlain is a mesotrophic lake bordering the states of New York and
Vermont and the Canadian province Quebec. The lake lies between the
Adirondack Mountains in the west and the Green Mountains of Vermont
to the east. Its orientation is predominantly north and south spanning
a length of 193 km, and it is relatively narrow with its widest part
extending 19 km. The surface area of the lake is 1127 kin' and mean
depth is 19.5m, with a maximum depth of 122m. Large amplitude internal
seiches and bores have recently been observed (Hunkins et al. 1998),
and an extensive field program is being conducted to study the lake's
circulation and mixing. Part of the observation strategy involves Lagrangian
experiments, which began in summer 2003. Both surface tracking buoys
and subsurface buoyancy-controlled (RAFOS) buoys, were used to track
the baroclinic circulation. This marks the first time that we are aware
of that RAFOS technology has been used in a freshwater environment.
Millie, D. F., G. R. Weckman, H. W. Paerl, J. L. Pinckney, B. J. Bendis,
R. J. Pigg, and G. L. FAHNENSTIEL. Neural net modeling of estuarine
indicators: Hindcasting phytoplankton biomass and net ecosystem production
in the Neuse (North Carolina) and Trout (Florida) rivers, USA. Ecological
Indicators 6(3):589-608 (2006).
Phytoplankton biomass, as chlorophyll (Chl) a, and net ecosystem production
(NEP), were modeled using artificial neural networks (ANNs). Chl a varied
seasonally and along a saline gradient throughout the Neuse River (North
Carolina). NEP was extremely dynamic in the Trout River (Florida), with
phototrophic or heterotrophic conditions occurring over short-term intervals.
Physical and chemical variables, arising from meteorological and hydrological
conditions, created spatial and/or temporal gradients in both systems
and served as interacting predictors for the trends/patterns of Chl
a and NEP. ANNs outperformed comparable linear regression models and
reliably modeled Chl a concentrations less than 20 µg L-1 and
NEP values, denoting the apparent non-linear interactions among abiotic
and indicator variables. ANNs underestimated Chl a concentrations greater
than 20 µg L-1, likely due to the periodicity of data acquisition
not being sufficient to generalize system variability, the designated
‘lag’ effect for variables not being adequate to portray
estuarine flow dynamics, the exclusion of (one or more) variables that
would have improved prediction, and/or an unrealistic expectation of
network performance. Variables indicative of meteorological and hydrological
forcing and/or proxy measurements of phytoplankton had the greatest
relative impact on prediction of Chl a and NEP. Except for their predictive
capability, ANNs might appear to be of limited value for ecological
applications and problem solving; interpreting the absolute impact of
and/or interacting relationships among network variables is intrinsically
difficult. Statistical methods or ‘rule extraction’ algorithms
that convey comprehensible network interpretation are needed prior to
the routine use of ANNs in programs assessing and/or forecasting the
response of biotic indicators to perturbation or for a means to discern
estuarine function
Millie, D. F., G. R. Weckman, R. J. Pigg, P. A. Tester, J. DYBLE,
R. W. Litaker, H. J. Carrick, and G. L. FAHNENSTIEL. Modeling phytoplankton
abundance in Saginaw Bay, Lake Huron: Using artificial neural networks
to discern functional influence of environmental variables and relevance
to a Great Lakes observing system. Journal of Phycology 42:336-349
(2006).
Phytoplankton abundance, as chl a, in Saginaw Bay, Lake Huron was modeled
using artificial neural networks. Suites of abiotic variables served
as predictors for the trends/patterns in chl a concentrations. Spatial
and temporal gradients of sampling stations throughout the bay were
evident, with physical/chemical differences arising from hydrological/
meteorological forcing and zebra mussel recruitment. Chlorophyll a concentrations
displayed corresponding disparities; concentrations differed between
the inner and outer bays and varied intra- and inter-annually. Trained
networks reproduced the intrinsic variance and magnitude of chl a dynamics.
Modeled-measured concentrations best approximated a 1:1 relationship
in a hybrid network incorporating both supervised and unsupervised training
whereas concentrations greater than 15 lg/L were underestimated in networks
utilizing only supervised training, likely because of inadequate training
data. Variables indicative of phytoplankton nutrition, acting as proxy
measurements of algal biomass, and/or corresponding to descriptors of
hydrological and meteorological forcing had the greatest influence upon
modeled concentrations. A conjunctive decision tree and a novel sensitivity
analysis provided rule-based information and comprehensible interpretation
of relationships among multiple predictor variables. From this, the
‘‘knowledge’’ embedded in trained networks proved
extractable and usable for ecological theory generation and/or decision
making within water-quality problem solving. Forecasting initiatives
within the developing Great Lakes Observing System may be best served
by embedding neural networks in mechanistic models to quantitatively
initialize variables, qualitatively delineate conditions for projecting
ecological structure, and/or estimate deviations from predictability
within mechanistic simulations
NALEPA, T. F., D. L. FANSLOW, A. J. FOLEY III, G. A. LANG, B. J. EADIE,
and M. A. QUIGLEY. Continued disappearance of the benthic amphipod Diporeia
spp. in Lake Michigan: Is there evidence of food limitation? Canadian
Journal of Fisheries and Aquatic Sciences 63:872-890 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060003.pdf
Benthic surveys were conducted in the southern basin of Lake Michigan
and throughout the lake to assess trends in benthic populations, emphasizing
recent changes in densities of the benthic amphipod Diporeia spp. and
dreissenid mussels. In the southern basin, Diporeia populations declined
89%, 91%, and 45% between 1993 and 2002 at sites <30, 31–50,
and 51–90 m, respectively. Lakewide, the population declined 65%
between 1994–1995 and 2000. Over the same time period, dreissenid
densities, particularly Dreissena bugensis, increased. Intensive studies
at 45 m sites in the southeastern region examined changes in lipid content,
age structure, and benthic food inputs relative to the hypothesis that
food limitation was a factor in Diporeia’s disappearance. As Diporeia
densities declined to zero, length–weight remained unchanged,
and lipid content generally increased. Recruitment still occurred, but
the young did not survive to become adults. Based on organic carbon,
biogenic silica, and chlorophyll collected in sediment traps and found
in the upper sediments, pelagic inputs to the benthic region still occurred.
Our field observations and laboratory experiments did not disprove the
hypothesis that food limitation from dreissenid filtering activities
was the cause of the decline, but direct relationships between the loss
of Diporeia and indicators of food availability were difficult to establish
NALEPA, T. F., D. L. FANSLOW, A. J. FOLEY III, G. A. LANG, B. J. EADIE,
and M. A. QUIGLEY. Continued disappearance of the benthic amphipod Diporeia
spp. in Lake Michigan: Is there evidence for food limitation? Aquatic
Invaders 17(3):1-12 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060018.pdf
The increased spread of aquatic invasive species has led to the growing
realization that these invaders, either individually or in concert,
can change ecosystems at many levels of organization (Simon and Townsend
2003). A striking example is the Great Lakes ecosystem where, over the
past 10-15 years, species invasions have led to the loss of native species,
altered pathways of energy and nutrient flux through food webs, and
redefined fundamental understanding of ecosystem function (Nalepa et
al. 1996; Vanderploeg et al. 2002; Hecky et al. 2004). When considering
imposed changes within the Great Lakes, perhaps the most large-scale,
and certainly the most equivocal, has been the disappearance of the
deepwater amphipod Diporeia spp. Declines in Diporeia populations have
recently been documented in all the lakes except Lake Superior, and
large areas in southeastern Lake Michigan (Nalepa et al. 1998), outer
Saginaw Bay, Lake Huron (Nalepa et al. 2003), eastern Lake Erie (Dermott
and Kerec 1997), and Lake Ontario (Dermott 2001; Lozano et al. 2001)
are now mostly devoid of this organism
NALEPA, T. F., D. C. Rockwell, and D. W. Schloesser. Disappearance
of the amphipod Diporeia spp. in the Great Lakes: Workshop summary,
discussion, and recommendations. NOAA Technical Memorandum GLERL-136.
NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI,
20 pp. (2006). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-136/tm-136.pdf
A workshop was held in October, 2006 to discuss population status
and causes of the disappearance of the benthic amphipod Diporeia spp.
in the Great Lakes, and to provide recommendations for future research.
Recent surveys indicate that Diporeia continues to decline in Lakes
Michigan, Huron, and Ontario, but surveys in Lake Superior are conflicting.
One data set shows that the population in Lake Superior is declining
in offshore regions (> 90 m) but not in nearshore regions (< 90
m). Other data sets show that the population is stable throughout the
lake. Reasons for this discrepancy were not resolved. In the other lakes,
Diporeia are now rare or completely gone at depths < 90 m, and are
declining at depths > 90 m. Latter declines are preceding the expansion
of Dreissena bugensis (quagga mussel) from shallow to deeper regions.
While there is a strong negative relationship between Diporeia and Dreissena
in the Great Lakes, Diporeia remains abundant in the Finger Lakes, New
York, despite the long-term presence of Dreissena. There are areas in
the Great Lakes where Diporeia seemed to persist but are now declining,
indicating that environmental conditions do play a mitigating role to
some extent. While there was agreement that Dreissena was the cause
of the disappearance of Diporeia in the Great Lakes, a survey of workshop
participants indicated no clear consensus on potential mechanisms for
the negative response. The most popular theories were food limitation
directly or indirectly related to dreissenid filtering activities, a
toxic by-product associated with dreissenid biodeposits, and an introduced
pathogen/disease. Based on previous field surveys and laboratory experiments,
there are inconsistencies in each of these theories, which may imply
a multitude of causative factors whose relative importance may vary
depending on specific environmental conditions. Given the potential
for multi-stressors, techniques that provide genomic or protein profiles
offer promise in defining a specific cause. Included among the recommendations
for future research are continued monitoring of Diporeia in the Finger
Lakes along with an assessment of conditions that allow it to persist,
experiments to further define a dreissenid by-product that negatively
impacts Diporeia, the development of genomic and protein expressions
specific for Diporeia, a better definition of taxonomic status, and
further efforts to characterize/resolve conflicting trends in offshore
populations in Lake Superior.
Osgood, K., N. Cyr, O. C. T., J. Polovina, D. J. SCHWAB, and P. Stabeno.
Ecosystem responses for climate variability. White Paper #1. In Ecosystem
Science Capabilities Required to Support NOAA's Mission in the Year
2020. NOAA Technical Memorandum NMFS-F/SPO-74. S.A. Murawski and
G.C. Matlock (Eds.). NOAA, National Marine Fisheries Service, Silver
Spring, MD, 6-14 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/2006tm74.pdf
Variations in the world’s climate have significant implications
for the productivity and structure of marine and coastal (including
Great Lakes) ecosystems ranging from the tropics to the poles. Climate-driven
variability of environmental conditions is manifest on many time and
space scales, including year-to-year variation, multi-year (e.g., El
Niño-Southern Oscillation [ENSO]), and decadal scales (e.g.,
Pacific Decadal Oscillation, North Atlantic Oscillation, and Arctic
Oscillation). In addition to this shorter-term variability, the Earth’s
climate system has demonstrably warmed on both global and regional scales
since the pre-industrial era impacting ice extent (IPCC, 2001). As a
consequence of global warming and subsidence, sea levels continue to
rise and the rate of rise is projected to accelerate. Precipitation
and resulting rates of runoff are predicted to change significantly
over the next century. These variations and changes in environmental
conditions have profound implications for ecosystems and the human activities
that are dependent on them by changing the distributions and productivity
of living resources.
PANGLE, K. L., and S. D. PEACOR. Non-lethal effect of the invasive
predator Bythotrephes longimanus on Daphnia mendotae. Freshwater
Biology 51:1070-1078 (2006).
1. We evaluated the antipredator behaviour of Daphnia mendotae to the
invasive invertebrate predator, Bythotrephes longimanus, and the consequent
effect of the predator on prey growth rate (referred to as a non-lethal
effect of the predator)
2. In a laboratory experiment, Daphnia in the absence of Bythotrephes
kairomones remained in the top, warmer regions of experimental columns,
whereas in the presence of Bythotrephes kairomones, Daphnia migrated
vertically, occupying a middle region by night and a low, cold region
during the day. Over a 4-day experiment, the vertical migration induced
by Bythotrephes caused a 36% reduction in the somatic growth rate of
Daphnia, a level that is sufficient to have an effect on prey population
growth rate
3. A second laboratory experiment indicated that concentrations of
Bythotrephes kairomones in water taken directly from the field (Lake
Michigan) were high enough to induce behavioural shifts that led to
these large reductions in somatic growth rate.
4. Our results identify a means by which Bythotrephes has substantial effects
on native prey populations other than through direct consumption.
PEACOR, S. D., and C. A. Pfister. Experimental and model analyses
of the effects of competition on individual size variation in wood frog
(Rana sylvatica) tadpoles. Journal of Animal Ecology
75:990-999 (2006).
1. Size variation is a ubiquitous feature of animal populations and
is predicted to strongly influence species abundance and dynamics; however,
the factors that determine size variation are not well understood.
2. In a mesocosm experiment, we found that the relationship between
mean and variation in wood frog (Rana sylvatica) tadpole size is qualitatively
different at different levels of competition created by manipulating
resource supply rates or tadpole density. At low competition, relative
size variation (as measured by the coefficient of variation) decreased
as a function of mean size, while at high competition, relative size
variation increased. Therefore, increased competition magnified differences
in individual performance as measured by growth rate.
3. model was developed to estimate the contribution of size-dependent factors
(i.e. based on size alone) and size-independent factors (i.e. resulting
from persistent inherent phenotypic differences other than size that
affect growth) on the empirical patterns.
4. Model analysis of the low competition treatment indicated that size-dependent
factors alone can describe the relationship between mean size and size
variation. To fit the data, the size scaling exponent that describes
the dependence of growth rate on size was determined. The estimated
value, 0·83, is in the range of that derived from physiological
studies.
5. At high competition, the model analysis indicated that individual differences
in foraging ability, either size-based or due to inherent phenotypic
differences (size-independent factors), were much more pronounced than
at low competition. The model was used to quantify the changes in size-dependent
or size-independent factors that underlie the effect of competition
on size-variation. In contrast to results at low competition, parameters
derived from physiological studies could not be used to describe the
observed relationships.
6. Our experimental and model results elucidate the role of size-dependent
and size independent factors in the development of size variation, and
highlight and quantify the context dependence of individual (intrapopulation)
differences in competitive abilities.
Plattner, S., D. M. MASON, G. A. LESHKEVICH, D. J. SCHWAB, and E.
S. Rutherford. Classifying and forecasting coastal upwellings in Lake
Michigan using satellite derived temperature images and buoy data. Journal
of Great Lakes Research 32:63-76 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060008.pdf
Coastal upwellings are common in the Great Lakes but have lacked enumeration
and systematic classification of spatial extent, frequency, duration,
and magnitude. Near real-time sea surface temperature (SST) images derived
from the Advanced Very High Resolution Radiometer (AVHRR) provide indices
of upwelling events, but visual inspection of daily images can be tedious.
Moreover, the definition of what constitutes an upwelling from AVHRR
data is subjective. We developed a semi-automated method to classify
upwellings during the period of thermal stratification using daily,
cloud-free surface temperature charts from AVHRR SST data. Then we statistically
evaluated the location, frequency, magnitude, extent, and duration of
upwelling events in Lake Michigan from 1992–2000. Further, we
analyzed meteorological data from the National Data Buoy Center buoys
in an attempt to improve the reliability of the classification and to
provide a means for future forecast of coastal upwelling. Although variable,
upwelling events along the western shoreline were preceded by 4 days
of southerly and west-to-northwesterly winds, while upwelling events
occurring along the eastern shore were preceded by 4 days of northerly
winds. Probability of an upwelling event occurring was a function of
the direction-weighted wind speed, reaching a 100% probability at direction
weighted wind speeds of 11 m s–1 for the western shore. Probability
of an upwelling occurrence along the east coast reached 73% at 11 m
s–1 and 100% at 13 m s–1. Continuous measurements of wind
data with a sufficient temporal resolution are required during the entire
upwelling season to improve the predictability of upwellings
POTHOVEN, S. A., and T. F. NALEPA. Feeding ecology of lake whitefish
in Lake Huron. Journal of Great Lakes Research 32:489-501 (2006).
http://www.glerl.noaa.gov/pubs/fulltext/2006/20060030.pdf
We determined diet composition, feeding strategy, prey size, and effects
of prey type on food weight and energy in stomachs for lake whitefish
Coregonus clupeaformis in Lake Huron during 2002–04. Age-0 lake
whitefish (73–149 mm TL) ate mainly large-bodied cladoceran zooplankton
in the summer (July–mid September). Medium lake whitefish (≤
350 mm TL excluding age-0) generally ate softbodied macroinvertebrates,
especially Chironomidae larvae and pupae, in the spring (mid May-June).
Zooplankton, if eaten, were generally most important in the summer.
Molluscs were generally a minor part of medium lake whitefish diets.
Large lake whitefish (> 350 mm) mainly ate molluscs, particularly
quagga mussels (Dreissena bugensis), despite geographic differences
in mussel abundance. Large-bodied crustaceans (Diporeia spp., Mysis
relicta, Isopoda) were a minor part of large lake whitefish diets. Lake
whitefish demonstrated a flexible feeding strategy, with individual
specialization on some prey and generalized feeding on others. The size
of benthic prey (Diporeia spp., Chironomidae, and Dreissena spp.) eaten
increased with fish size and influenced the energetic value of prey
for medium and large lake whitefish. The type of prey eaten affected
the food and energy intake differently for each size class of lake whitefish.
Age-0 lake whitefish that ate mainly zooplankton had more food and energy
in stomachs than fish eating shelled prey or other macroinvertebrates.
On the other hand, food weight in stomachs did not differ across prey
groups for medium fish, but energy in stomachs was lowest for fish that
ate shelled prey. For large lake whitefish, there was no difference
in food weight or energy in stomachs for different prey groups
POTHOVEN, S. A., T. F. NALEPA, C. P. Madenjian, R. R. Rediske, P.
J. Schneeberger, and J. X. He. Energy density of lake whitefish Coregonus
clupeaformis in Lakes Huron and Michigan. Environmental Biology
of Fishes 76:151-158 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060031.pdf
We collected lake whitefish Coregonus clupeaformis off Alpena and
Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA
in Lake Michigan during 2002–2004. We determined energy density
and percent dry weight for lake whitefish from both lakes and lipid
content for Lake Michigan fish. Energy density increased with increasing
fish weight up to 800 g, and then remained relatively constant with
further increases in fish weight. Energy density, adjusted for weight,
was lower in Lake Huron than in Lake Michigan for both small (≤800
g) and large fish (>800 g). Energy density did not differ seasonally
for small or large lake whitefish or between adult male and female fish.
Energy density was strongly correlated with percent dry weight and percent
lipid content. Based on data from commercially caught lake whitefish,
body condition was lower in Lake Huron than Lake Michigan during 1981–2003,
indicating that the dissimilarity in body condition between the lakes
could be long standing. Energy density and lipid content in 2002–2004
in Lake Michigan were lower than data for comparable sized fish collected
in 1969–1971. Differences in energy density between lakes were
attributed to variation in diet and prey energy content as well as factors
that affect feeding rates such as lake whitefish density and prey abundance.
QUINN, F. H., and C. E. SELLINGER. A reconstruction of Lake Michigan-Huron
water levels derived from tree ring chronologies for the period 1600-1961.
Journal of Great Lakes Research 32:29-39 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060006.pdf
A dendrochronolgy of annual precipitation and air temperatures from six Great
Lakes locations was used to reconstruct Lake Michigan-Huron water levels
from 1600–1961 representing the present St. Clair River channel
conditions and basin land cover. The reconstructions are based upon
a multi-linear regression model relating multi-year annual precipitation
and air temperature to annual water levels. An increased frequency of
low lake levels was found to occur prior to the twentieth century, accompanied
by a major extreme in water levels, greater than that experienced in
the historical record, in the early 1600s. The comparison of simulated
and measured water levels also indicates that the impact of some of
the channel changes in the St. Clair River may be underestimated and
that the major drop in lake level in the 1880s may be due to erosion
as well as to decreased precipitation. The occurrence of extreme levels
around 1640, in 1838, and in 1986 suggests a return interval of 150–190
years for extreme lake levels. The analysis also suggests that the variability
of lake levels has greatly decreased over the last century when comparing
tree-ring-derived level variability. Thus climatic periods used for
the development of the current regulation plans may not be representative
of the longer-term climate and lake levels.
RAIKOW, D. F., D. F. REID, E. E. MAYNARD, and P. F. LANDRUM. Sensitivity
of aquatic invertebrate resting eggs to SeaKleen (Menadione): A test
of potential ballast tank treatment options. Environmental Toxicology
and Chemistry 25(2):552-559 (2006).
The introduction of aquatic species in resting life stages by the release
of ballast water is a less well-known but potentially important invasive
species vector. Best-management practices designed to minimize transport
of ballast water cannot eliminate this threat, because residual water
and sediment are retained in ballast tanks after draining. To evaluate
the potential efficacy of chemical treatment of residual material in
ship ballast tanks, the present study examined the acute toxicity of
the proposed biocide SeaKleen® (menadione; Garnett, Watkinsville,
GA. USA) on resting eggs of Brachionus plicatilis (a marine rotifer),
a freshwater copepod, Daphnia mendotae (a freshwater cladoceran), and
Artemia sp. (a marine brine shrimp). SeaKleen was toxic to resting eggs
of all taxa. Daphnia mendotae resting eggs encased in protective ephippia
were the least sensitive, as indicated by a 24-h lethal concentration
of toxicant to 90% of organisms of 8.7 mg/L (95% confidence interval,
± 0.1 mg/L). SeaKleen induced teratogenic effects in D. mendotae
and Artemia sp. Exposure to sunlight quickly degraded SeaKleen, which
lost all toxicity after 72 h outdoors. SeaKleen increased in toxicity
slightly after 72 h in darkness. Burial of D. mendotae ephippia in natural
lake sediment reduced SeaKleen toxicity by a factor of 20. Reduced toxicity
in the presence of sediment raises serious doubts as to the potential
for this, or any, chemical biocide to kill aquatic invertebrate resting
stages buried in sediment retained in ship ballast tanks.
Reavie, E. D., J. A. ROBBINS, E. F. Stoermer, M. S. V. Douglas, G.
E. Emmert, N. R. MOREHEAD, and A. Mudroch. Paleolimnology of a fluvial
lake downstream of Lake Superior and the industrialized region of Sault
Saint Marie. Canadian Journal of Fisheries and Aquatic Sciences
62:2586-2608 (2005). http://www.glerl.noaa.gov/pubs/fulltext/2005/20050025.pdf
A paleolimnological study was undertaken to describe the past environment
of the St. Mary’s River downstream of Lake Superior. Two sediment
cores were obtained from the deepest part of Lake George, a fluvial
lake in the river system. Rigorous analyses of radionuclides (210Pb,
226Ra, and 137Cs) and chemical properties provided an accurate sediment
chronology. More than 450 diatom species from 47 genera were identified.
Diatom and geochemical data indicated gradual environmental change in
response to anthropogenic activities, including logging, hydrologic
manipulation, and steel, leather, and paper industries. A decline in
water quality occurred gradually from the late 1800s through the 20th
century in response to human activities, as was apparent from an increase
in eutrophic–planktonic diatom taxa. A decline in benthic taxa
and an increase in contaminant metals were also contemporaneous with
impacts during the 20th century. Subfossil diatoms were similar to those
recorded in paleolimnological investigations from the Great Lakes. However,
diatom profiles indicate that the algal supply from upstream Lake Superior
has been minimal and that the cores mainly reflect environmental characteristics
of the near-upstream environment. Despite stochastic sedimentary regimes
and complex habitats in the lotic system, this study reinforces the
value of river paleolimnology at carefully selected sites.
SANO, L. L., S. M. Bartell, and P. F. LANDRUM. Decay model for biocide
treatment of unballasted vessels: Application for the Laurentian Great
Lakes. Marine Pollution Bulletin 20:1050-1060 (2005).
A biocide decay model was developed to assess the potential efficacy and environmental
impacts associated with using glutaraldehyde to treat unballasted overseas
vessels trading on the Laurentian Great Lakes. The results of Monte
Carlo simulations indicate that effective glutaraldehyde concentrations
can be maintained for the duration of a vessel s oceanic transit (approximately
9–12 days): During this transit, glutaraldehyde concentrations
were predicted to decrease by approximately 10% from initial treatment
levels (e.g., 500 mg L 1). In terms of environmental impacts, mean glutaraldehyde
concentrations released at Duluth-Superior Harbor, MN were predicted
to be 100-fold lower than initial treatment concentrations, and ranged
from 3.2 mg L 1 (2 SD: 2.74) in April to 0.7 mg L 1 (2 SD: 1.28) in
August. Sensitivity analyses indicated that the reballasting dilution
factor was the major variable governing final glutaraldehyde concentrations;
however, lake surface temperatures became increasingly important during
the warmer summer months.
Schiesari, L., S. D. PEACOR, and E. E. Werner. The growth-mortality
tradeoff: Evidence from Anuran larvae and consequences for species distribution.
Oecologia 149:194-202 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060019.pdf
A tradeoff affecting the ability to grow under high versus low resource
levels has been commonly hypothesized to influence species distributions
across resource gradients in a wide variety of taxa. This influence
is dependent on individual growth being proportional to traits that
affect demographic processes such as mortality. However, data on how
individual growth scales with demographic performance are rare. We conducted
a mesocosm experiment, and reanalyzed data from a similarly designed
Weld experiment, to examine the relationship between growth and mortality
in two tadpole species that segregate across a resource gradient. Overall,
environmental conditions leading to faster growth also lead to lower
mortality rates. However, species differed in this relationship. Leopard
frogs achieved faster growth than wood frogs, but their absolute mortality
was greater and increased steeply as growth decreased. Conversely, absolute
mortality of wood frogs was lower and less strongly dependent on growth.
These interspecies differences suggest a second tradeoff, that between
maximizing growth rates or minimizing mortality, with potentially important
demographic consequences. Leopard frogs grow faster than wood frogs
in productive ponds, but are excluded from unproductive ponds dominated
by wood frogs due to accelerating mortality rates with declining realized
growth. A review of the literature suggests that in diverse taxa, including
plants, microcrustaceans and drosophilids, patterns in mortality are
consistent with this tradeoff indicating that the mechanism we demonstrate
could be a link between individual performance and demographic rates
influencing species distributions in other systems.
Schuler, L. J., P. F. LANDRUM, and M. J. Lydy. Comparative toxicity
of fluoranthene and pentachlorobenzene to three freshwater invertebrates.
Environmental Toxicology and Chemistry 25(4):985-994 (2006).
This study examined the temporal component of pentachlorobenzene lethal body
residues among three freshwater invertebrates. Also, using previous
fluoranthene data allowed a more detailed examination of the role of
biotransformation in lethal body residues and comparisons of lethal
residues across chemical classes. Time-dependent toxicity of fluoranthene
and pentachlorobenzene were compared among Hyalella azteca, Chironomus
tentans, and Diporeia spp. Lethal body residues required for 50% mortality
(LR50) were not constant and decreased with exposure time for all species.
Fluoranthene was most toxic to C. tentans with LR5O values of 0.38 mmol.g-1
at 2 d to 0.15 mmol.g-1 at 10 d and least toxic to Diporeia spp. with
values of 9.97 mmol.g-1 at 10 d to 3.67 mmol.g-1 at 28 d. The LR5O values
for H. azteca were intermediate and ranged from 2.25 mmol.g-1 at 5 d
to 0.56 mmol.g-1 at 28 d. Pentachlorobenzene LR5O values were less variable
among species and ranged from 1.20 mmol.g-1 at 4 d to 0.81 mmol.g-1
at 10 d for C. tentans, 5.0 mmol.g-1 at 20 d and 2.75 mmol.g-1 at 28
d for Diporeia spp., and 1.51 mmol.g-1 at 4 d and 0.71 mmol.g-1 at 28
d for H. azteca. When LR50 values for fluoranthene and pentachlorobenzene
were compared at steady state, the lethal residues for the amphipod
species were within the range expected for nonpolar narcotic chemicals
(anesthetics); however, C. tentans was more sensitive to fluoranthene
than pentachlorobenzene, confirming our previous hypothesis that biotransformation
of fluoranthene likely produces a metabolite(s) acting by some specific
mechanism of action. The information collected from this study allows
a greater understanding of residue-response relationships, specifically
relative species sensitivities.
SCHWAB, D. J., B. J. EADIE, R. A. ASSEL, and P. J. Roebber. Climatology
of large sediment resuspension events in southern Lake Michigan. Journal
of Great Lakes Research 32:50-62 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060007.pdf
Lake Michigan, particularly the southern basin, is subject to recurrent episodes
of massive sediment resuspension by storm-induced waves and currents.
The purpose of this paper is to investigate the climatology of these
events for Lake Michigan, including an analysis of associated meteorological
conditions. This paper begins by examining turbidity records from two
water treatment plants (Chicago, IL and St. Joseph, MI) for which long-term
records are available. The turbidity records from the two plants show
significant differences indicating that turbidity measurements from
a single location would probably not be representative of a basin-wide
climatology. A one-dimensional sediment resuspension and deposition
model for fine-grained sediments is then developed and calibrated with
data from the water treatment plants. The one-dimensional model is applied
at 15 points around the southern basin for a 45-year period for which
Lake Michigan wave climatology is available and the results are averaged
to obtain a basin-wide turbidity index (Southern Lake Michigan Turbidity
Index, SLMTI). A frequency distribution of the turbidity index is presented
and meteorological conditions associated with the largest events are
examined. Our analysis indicates that significant resuspension events
in southern Lake Michigan are usually caused by a strong cyclone passing
to the east of the lake. The most likely time of the year for this to
occur is October to April. There is an average of 1 event per year with
SLMTI above 25 mg/L and each event typically lasts about 3 days. Our
analysis indicates that events have occurred more frequently since the
late 1980s as the number of winter storms has increased and ice cover
has decreased.
Stroud, J., B. M. Lesht, D. J. SCHWAB, D. BELETSKY, and M. L. Stein.
Tracking suspended sediment motion in Lake Michigan by combining satellite
images with a numerical model. Technical Report No. 38. The University
of Chicago, Center for Integrating Statistical and Environmental Science,
Chicago, IL, 36 pp. (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060027.pdf
Because satellite observations are synoptic, collected frequently,
and highly resolved on geophysical scales, they can be a valuable source
of information for development and application of numerical models.
Data derived from satellite sensors may be used in model evaluation
studies, as well as for operational and prognostic updating of both
model state and forcing variables. Although satellite data are used
routinely with many types of operational atmospheric models, little
work has been done to integrate satellite data with models of aquatic
systems. In this paper, we develop and examine schemes for combining
daily images obtained by the Sea-viewing Wide Field Spectrometer (SeaWiFS)
with a two-dimensional sediment transport model representing southern
Lake Michigan. We perform a forecasting study focused on two-month period
in spring 1998 when a large storm caused substantial amounts of sediment
resuspension and horizontal sediment transport in the lake. We find
that data assimilation schemes improve forecast root-mean-square-error
(RMSE) by 40% over purely model-based approaches and by 20% over purely
data-based approaches.
Tirelli, V., D. Borme, F. Tulli, M. Cigar, S. Fonda Umani, and S.
B. BRANDT. Energy density of anchovy, Engraulis encrasicolus L.
in the Adriatic Sea. Journal of Fish Biology 68:982-989 (2006).
European anchovy Engraulis encrasicolus, with total lengths ranging from 40
-0 to 132-5 mm, were sampled during October 2002 and May 2003 in the
northern Adriatic Sea in order to estimate their energy densities (ED).
A highly significant (P < 0-001) relationship between ED (y) (J g-1wet
mass) and per cent dry mass (x) was found: y =321x - 3316-9 (n = 161,
r2 = 0 - 82).
VANDERPLOEG, H. A., and M. R. Roman. Introduction to special section
on analysis of zooplankton distributions using the optical plankton
counter. Journal of Geophysical Research 111(C05S01):doi:10.1029/2006JC003598
(2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060015.pdf
We briefly introduce the optical plankton counters (OPCs) currently
in use and summarize major themes and conclusions of papers from this
special section. These collected papers demonstrate that the OPC and
the new laser OPC (LOPC) are useful tools for mapping fine-scale distributions
of zooplankton over broad expanses of space and for examining patterns
in the size structure of zooplankton communities, which give insights
into the top-down and bottom-up forces affecting them. The LOPC or OPC
are particularly valuable sensors when used in conjunction with an array
of other sensors on a tow body so that investigators can synoptically
measure physical and biotic variables. Caution must be exercised in
using the OPC or LOPC because there are times when nonzooplankton particles
comprise a significant portion of the particles counted. The contribution
of nonzooplankton particles to the total seston varies with system and
conditions
Werner, E. E., and S. D. PEACOR. Lethal and non-lethal predator effects
on an herbivore guild mediated by system productivity. Ecology
87(2):347-361 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060011.pdf
Indirect effects propagated through intervening species in a food web
have important effects on community properties. Traditionally, these
indirect effects have been conceptualized as mediated through density
changes of the intervening species, but it is becoming increasingly
apparent that those mediated through trait (phenotypic) responses also
can be very important. Because density- and trait-mediated indirect
effects have different properties, it is critical that we understand
the mechanisms of transmission in order to predict how they will interact,
and when or where they will be important. In this study, we examined
the mechanisms and consequences of the lethal (density mediated) and
nonlethal (trait-mediated) effects of a larval odonate predator on a
guild of four herbivore species (a larval anuran and three species of
snails) and their resources. We also manipulated system productivity
in order to explore the effects of environmental context on the transmission
of these two types of indirect effects. We show that trait mediated
effects arising from the predator can be very strong relative to density-mediated
effects on both the competing herbivores and the species composition
and production of their resources. A number of these indirect effects
are shown to be contingent on productivity of the system. We further
present evidence that trait- and density-mediated indirect effects originating
from a predator may be transmitted independently through different routes
in a food web, particularly when spatial responses of the transmitting
prey are involved. Finally, effects on prey growth due to trait responses
to the predator varied from negative to positive in predictable ways
as a function of time and indirect effects on the larger food web. These
results indicate the important role that trait-mediated indirect effects
can play in trophic cascades and keystone predator interactions, and
we discuss how the mechanisms involved can be incorporated in theory.
Zhulidov, A. V., T. F. NALEPA, A. V. Kozhara, D. A. Zhulidov, and T.
Y. Gurtovaya. Recent trends in relative abundance of two dreissenid
species, Dreissena polymorpha and Dreissena bugensis
in the lower Don River System, Russia. Archives fur Hydrobiologie
165(2):209-220 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060010.pdf
We sampled sites in the lower Don River system, Russia between 1977
and 2004 (5 sites) or between 1999 and 2004 (10 sites) to determine
relative trends in two dreissenid species, Dreissena bugensis and Dreissena
polymorpha. The sites were located in the main river, in connecting
reservoirs, and in a major tributary, the Manych River. For sites sampled
beginning in 1977, D. bugensis was first found in the lower river in
1980 and then more upstream in 1991. The relative proportion of D. bugensis
increased to reach a maximum of 30–50% of the dreissenid population
by 1999. After 1999, this species decreased at 14 of the 15 sites. At
sites in the Don River, the proportion that D. bugensis comprised of
the total dreissenid population after 1999 declined from 25–50%
to 10–18%, whereas at sites in the Manych River the proportion
declined from 65–75% to 33–43%. The decline of D. bugensis
relative to D. polymorpha is unique; in most other water bodies D. bugensis
displaces D. polymorpha over time because of its superior physiological
attributes. Reasons for the relative decline of D. bugensis are unclear,
but we speculate that selective predation by fish may be a potential
factor.
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