Arhonditsis, G.B., H.W. Paerl, L.M. Valdes-Weaver, C.A. STOW,
L.J. Steinberg, and K. H. Reckhow. Application of Bayesian
structural equation modeling for examining phytoplankton dynamics in
the Neuse River Estuary (North Carolina, USA). Estuarine, Coastal,
and Shelf Science 72:63-80 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070032.pdf
We introduce a Bayesian structural equation modeling framework to
explore the spatiotemporal phytoplankton community patterns in the Neuse
River Estuary (study period 1995-2001). The initial hypothesized model
considered the influence of the physical environment (flow, salinity,
and light availability), nitrogen (dissolved oxidized inorganic nitrogen,
and total dissolved inorganic nitrogen), and temperature on total phytoplankton
biomass and phytoplankton community structure. Generally, the model
gave plausible results and enabled the identification of the longitudinal
role of the abiotic factors on the observed phytoplankton dynamics.
River flow fluctuations and the resulting salinity and light availability
changes (physical environment) dominate the up-estuary processes and
loosen the coupling between nitrogen and phytoplankton. Further insights
into the phytoplankton community response were provided by the positive
path coefficients between the physical environment and diatoms, chlorophytes,
and cryptophytes in the down-estuary sections. The latter finding supports
an earlier hypothesis that these three groups dominate the phytoplankton
community during high freshwater conditions as a result of their faster
nutrient uptake and growth rates and their tolerance on low salinity
conditions. The relationship between dissolved inorganic nitrogen concentrations
and phytoplankton community becomes more apparent as we move to the
down-estuary sections. A categorization of the phytoplankton community
into cyanobacteria, dinoflagellates and an assemblage that consists
of diatoms, chlorophytes, and cryptophytes provided the best results
in the upper and middle segments of the estuary. Finally, the optimal
down-estuary grouping aggregates diatoms and chlorophytes, lumps together
dinoflagellates with cryptophytes, while cyanobacteria are treated separately.
These structural shifts in the temporal phytoplankton community patterns
probably result from combined bottom-up and top-down control effects.
BELETSKY, D., D.J. SCHWAB, and M.J. McCORMICK. Modeling
the 1998-2003 summer circulation and thermal structure in Lake Michigan.
Journal of Geophysical Research 111:C10010, doi:10.1029/2005JC003222
(2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060032.pdf
A three-dimensional primitive equation numerical model was applied to
Lake Michigan on a 2 km grid for 6 consecutive years to study interannual
variability of summer circulation and thermal structure in 1998–2003.
The model results were compared to long-term observations of currents
and temperature at seven moorings and two NOAA buoys. The accuracy of
modeled currents improved considerably relative to previous summer circulation
modeling done on a 5 km grid, while the accuracy of temperature simulations
remained the same. Particle trajectory model results were also compared
with satellite-tracked surface drifter observations. Large-scale circulation
patterns tend to be more cyclonic (counterclockwise) toward the end
of summer as the thermocline deepens and density effects become more
important. Circulation in southern Lake Michigan appears to be more
variable than circulation in northern Lake Michigan. An important new
feature not previously seen in observations was found in southern Lake
Michigan: an anticyclonic gyre extending northward from the southern
shore of Lake Michigan, sometimes occupying the entire southern basin.
BRANDT, S.B., and M.B. LANSING. The International
Field Years on Lake Erie (IFYLE). In State of the Great Lakes Annual
Report, 20th Anniversary. Office of the Great Lakes, Michigan Department
of Environmental Quality, Lansing, MI, 26-28 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060048.pdf
The National Oceanic and Atmospheric Administration’s (NOAA’s)
Great Lakes Environmental Research Laboratory (GLERL), in collaboration
with researchers from the U.S., Canada, and Europe, have initiated what
is believed to be the largest, most comprehensive, multidisciplinary
research effort ever conducted on Lake Erie: the International Field
Years on Lake Erie (IFYLE). Lake Erie faces wide and varied threats
to its health and integrity, including harmful algal blooms (HABs) in
the west basin, recurring low oxygen episodes (“dead zones”)
in the central basin, and invasive species as well as extremes in natural
phenomena such as high and low water levels, and climate variability.
Each of these threats has the potential to disrupt normal food webs
and ecosystem processes, and thus, jeopardize Lake Erie’s ability
to provide healthy fish populations, safe drinking water, and bacteria-free
beaches. Since all of these factors are interrelated, the scientific
framework for effective management will require ecosystem-level research,
particularly relative to biological-physical-chemical interactions on
a lake-wide basis and over a range of time and space scales. Full report
available at: http://www.michigan.gov/documents/deq/deq-ogl-SOGL_report_185661_7.pdf
Cangelosi, A.A., N.L. Mays, M.D. Balcer, E.D. Reavie, D.M.
Reid, R. STURTEVANT, and X. Gao. The response of zooplankton
and phytoplankton from the North American Great Lakes to filtration.
Harmful Algae 6:547-566 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070013.pdf
Filtration of ballast water was investigated as a means of minimizing
the introduction of nonindigenous zooplankton and phytoplankton by ships
visiting the North American Great Lakes-St. Lawrence Seaway system (GLSLSS).
An automatic backwash screen filtration (ABSF) system with nominal filtration
options of 25, 50, or 100 um was mounted on the deck of an operating
Seaway-sized dry bulk carrier, the MV Algonorth. Water was
pumped through the ABSF with a deck mounted pump at 341 m3 hr-1 during
routine ship operations in the GLSLSS, and effectiveness of the various
screen pore sizes at removing taxonomic categories of zooplankton and
phytoplankton was measured using matched treatment and control ballast
tanks. The smallest pore sizes (25 and 50 um) performed better than
the 100 um pore size at removing biological material. There was no difference
in the filtration efficiency of the 25 and 50 um screens relative to
macro- or microzooplankton in these tests, but this result was probably
due to low densities of macrozooplankton, and soft-bodied (aloricate)
characteristics of the microzooplankton present. The 25 and 50 um pore
sizes were subjected to more controlled tests on board a stationary
barge platform equipped with triplicate 700 L catchment bins moored
in Duluth Harbor of Lake Superior. In these tests, filter pore size,
organism size and rigidity influenced zooplankton removal efficiency
by the ABSF. The 25 um screen reduced both macrozooplankton and microzooplankton
significantly more than the 50 um screen. Zooplankton width was more
determinative of filtration performance than length, and both filters
removed loricate species of rotifers significantly more efficiently
than aloricate species of the same length and width size classes. The
25 and 50 um ABSF also significantly reduced algal densities, with the
exception of colonial and filamentous green algae (50 um only). Filter
efficiency relative to algal particles was influenced by filter pore
size, organism morphology and structure, and intake density, while algal
particle size was not determinative. This research provides compelling
evidence that 25 or 50 um filtration is a potentially powerful means
of reducing densities of organisms discharged by ships operating in
the Great Lakes but an additional treatment step would be necessary
to effectively minimize risk and meet the International Maritime Organization’s
discharge standards associated with organisms of all sizes in the water
column.
Chu, P., J.G.W. Kelley, A.-J. Zhang, G.A. LANG, and K.W. Bedford.
Skill assessment of NOS Lake Erie Operational Forecast System
(LEOFS). NOAA Technical Memorandum NOS CS 12. NOAA Office of Coast Survey,
Coast Survey Development Lab, Silver Spring, MD, 73 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/2007tmNOS_CS12
This document describes the Lake Erie Operational Forecast System
(LEOFS) and an assessment of its skill. The lake forecast system, based
on a hydrodynamic model, uses near real-time atmospheric observations
and numerical weather prediction forecast guidance to produce three-dimensional
forecast guidance of water temperature and currents and two-dimensional
forecasts of water levels. LEOFS is the result of technology transfer
of the Great Lake Forecasting System (GLFS) and the Great Lakes Coastal
Forecasting System (GLCFS) from The Ohio State University (OSU) and
NOAA’s Great Lakes Environmental Research Laboratory (GLERL) to
NOAA’s National Ocean Service.
CROLEY, T.E. II., J.F. Atkinson, and D.F. RAIKOW.
Hydrologic - Hydraulic - Ecologic resource sheds. Proceedings of the
Second IASTED International Conference, Water Resources Management,
Honolulu, HI, August 20-22, 2007. 164-169 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070035.pdf
We can quantify source areas contributing material to a location during
various time periods as resource sheds. Various kinds of resource sheds
and their source material distributions are defined. For watershed hydrology,
we compute resource sheds and their source material distributions with
a spatially distributed hydrology model by tracing material departing
from a cell (say 1 km2) over one time interval and arriving at the watershed
mouth in another time interval. This requires modeling all cells, but
only tracing contributions from one at a time. By then combining these
simulations for all cell loadings, we construct a map of the contributions
over the entire watershed for specific departure and arrival time intervals.
We then combine results of several sets of simulations to determine
the source distribution for any time period and infer resource sheds
from these mappings. For lake circulation, we discuss the construction
of resource sheds and their source distributions in the lake, by using
lake circulation models to drive particle tracers in reverse time, and
subsequent correction. We present Maumee watershed examples, discuss
methods of computation reduction and linkage with lake circulation models,
construct joint resource sheds in Lake Erie, and suggest areas of extension.
CROLEY, T. E. II., C. He, J.F. Atkinson, and D.F. RAIKOW.
Resource shed definitions and computations. NOAA Technical Memorandum
GLERL-141. NOAA, Great Lakes Environmental Research Laboratory, Ann
Arbor, MI, 35 pp. (2007). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-141/tm-141.pdf
When we consider a location with a material (e.g., water, pollutant,
sediment) passing through it, we can ask: Where did the material come
from and how long did it take to reach the location? We can quantify
the answer by defining the areas contributing to this location during
various time periods as resource sheds. Various kinds of resource sheds
and their source material distributions are rigorously defined and properties
derived. For watershed hydrology, we compute resource sheds and their
source material distributions with a spatially distributed hydrology
model by tracing material departing from a cell (say 1 km2) over one
time interval and arriving at the watershed mouth in another time interval.
This requires modeling all cells, but only tracing contributions from
one at a time. By then combining these simulations for all cell loadings,
we construct a map of the contributions over the entire watershed for
specific departure and arrival time intervals. We then combine results
of several sets of simulations to determine the source distribution
for any time period and infer resource sheds from these mappings. For
lake circulation, we discuss the construction of resource sheds and
their source distributions in the lake, by using lake circulation models
to drive particle tracers in reverse time, and subsequent correction.
We present examples for the Maumee River watershed in northern Ohio,
discuss methods of computation reduction, discuss linkage with a lake
circulation model to construct joint resource sheds in Lake Erie, and
suggest areas of extension for the future.
CROLEY, T.E. II., and C.F.M. Lewis. Warmer and drier
climates that make terminal Great Lakes. Journal of Great Lakes
Research 32:852-869 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060043.pdf
A recent empirical model of glacial-isostatic uplift showed that the
Huron and Michigan lake level fell tens of meters below the lowest possible
outlet about 7,900 14C years BP when the upper Great Lakes became dependent
for water supply on precipitation alone, as at present. The upper Great
Lakes thus appear to have been impacted by severe dry climate that may
have also affected the lower Great Lakes. While continuing paleoclimate
studies are corroborating and quantifying this impacting climate and
other evidence of terminal lakes, the Great Lakes Environmental Research
Laboratory applied their Advanced Hydrologic Prediction System, modified
to use dynamic lake areas, to explore the deviations from present temperatures
and precipitation that would force the Great Lakes to become terminal
(closed), i.e., for water levels to fall below outlet sills. We modeled
the present lakes with pre-development natural outlet and water flow
conditions, but considered the upper and lower Great Lakes separately
with no river connection, as in the early Holocene basin configuration.
By using systematic shifts in precipitation, temperature, and humidity
relative to the present base climate, we identified candidate climates
that result in terminal lakes. The lakes would close in the order: Erie,
Superior, Michigan-Huron, and Ontario for increasingly drier and warmer
climates. For a temperature rise of TºC and a precipitation drop of
P% relative to the present base climate, conditions for complete lake
closure range from 4.7T + P > 51 for Erie to 3.5T + P > 71 for
Ontario.
DeMARCHI, C., A. Georgakakos, and C. Peters-Lidard.
Probabilistic estimation of precipitation combining geostationary and
TRMM satellite data. Proceedings of Symposium HS3007 at IUGG2007, Remote
Sensing for Environmental Monitoring and Change Detection, Perugia,
Italy, July 2007. IAHS Publication 316, International Association of
Hydrological Sciences, pp. 70-77 (2007).
This paper presents a methodology for estimating precipitation that
combines precipitation rates observed by the TRMM satellite with infrared/-visible
(IR/VIS) images by geostationary satellites. The method detects IR patterns
associated with convective storms and characterizes their evolution
phases. Precipitation rates are estimated for each phase using IR/VIS
and terrain information. The approach is shown to improve the integration
of TRMM precipitation rates and IR/VIS data by differentiating major
storms from smaller events and noise, and by separating the precipitation
regime characteristic of each storm phase. Further, the procedure explicitly
quantifies the uncertainty of the precipitation estimates by computing
their probability distribution. The methodology was tested in the Lake
Victoria basin during the period 1996–1998 against data from >100
rain gauges, showing lower bias and better correlation with ground data
than commonly used methods, and reproducing the variability of precipitation
over a range of temporal and spatial scales.
DeMARCHI, C., A. Georgakakos, and C. Peters-Lidard.
Uncertainty characterization in a combined IR/Microwave scheme for remote
sensing of precipitation. Proceedings, Symposium HS2004 at IUGG2007,
Quantification and Reduction of Predictive Uncertainty for Sustainable
Water Resources Management, Perugia, Italy, July 2007. International
Association of Hydrological Sciences , IAHS Publication 313, pp. 70-77
(2007).
This paper presents a methodology for estimating precipitation that
combines data from the precipitation radar aboard the TRMM satellite
with infrared/visible (IR/VIS) images by geostationary satellites. The
approach estimates half-hour precipitation based on IR/VIS data, storm
stage, and terrain, and quantifies the uncertainty of the precipitation
estimates by computing their full probability distribution. The probabilistic
characterization is composed of a binomial distribution for the probability
of rain and a lognormal distribution for the conditional rain intensity.
Temporal and spatial autocorrelations are fully accounted for by using
spatially optimal estimator methods (kriging). The procedure is tested
in the Lake Victoria basin over the period 1996–1998 against data
from more than one hundred rain gauges, showing lower bias and better
correlation with ground data than commonly used methods and reproducing
precipitation variability over a range of temporal and spatial scales.
Fong, T.T., L.S. Mansfield, D.L. Wilson, D.J. SCHWAB, S.L.
Molloy, and J.B. Rose. Massive microbiological groundwater
contamination associated with a waterborne outbreak in Lake Erie, South
Bass Island, Ohio. Environmental Health Perspectives 115(6):856-864
(2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070015.pdf
A groundwater-associated outbreak affected approximately 1,450 residents
and visitors of South Bass Island, Ohio, between July and September
2004. OBJECTIVES: To examine the microbiological quality of groundwater
wells located on South Bass Island, we sampled 16 wells that provide
potable water to public water systems 15–21 September 2004. METHODS:
We tested groundwater wells for fecal indicators, enteric viruses and
bacteria, and protozoa (Cryptosporidium and Giardia).
The hydrodynamics of Lake Erie were examined to explore the possible
surface water–groundwater interactions. RESULTS: All wells were
positive for both total coliform and Escherichia coli. Seven wells tested
positive for enterococci and Arcobacter (an emerging bacterial
pathogen), and F+-specific coliphage was present in four wells. Three
wells were positive for all three bacterial indicators, coliphages,
and Arcobacter; adenovirus DNA was recovered from two of these wells.
We found a cluster of the most contaminated wells at the southeast side
of the island. CONCLUSIONS: Massive groundwater contamination on the
island was likely caused by transport of microbiological contaminants
from wastewater treatment facilities and septic tanks to the lake and
the subsurface, after extreme precipitation events in May–July
2004. This likely raised the water table, saturated the subsurface,
and along with very strong Lake Erie currents on 24 July, forced a surge
in water levels and rapid surface water–groundwater interchange
throughout the island. Landsat images showed massive influx of organic
material and turbidity surrounding the island before the peak of the
outbreak. These combinations of factors and information can be used
to examine vulnerabilities in other coastal systems. Both wastewater
and drinking water issues are now being addressed by the Ohio Environmental
Protection Agency and the Ohio Department of Health.
Ge, J., J. Qi, B M. LOFGREN, N. Moore, N. Torbick, and J.M.
Olson. Impacts of land use/cover classification accuracy on
regional climate simulations. Journal of Geophysical Research
112(D05107, doi:10.1029/2006JD007404):12 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070003.pdf
Land use/cover change has been recognized as a key component in global
change. Various land cover data sets, including historically reconstructed,
recently observed, and future projected, have been used in numerous
climate modeling studies at regional to global scales. However, little
attention has been paid to the effect of land cover classification accuracy
on climate simulations, though accuracy assessment has become a routine
procedure in land cover production community. In this study, we analyzed
the behavior of simulated precipitation in the Regional Atmospheric
Modeling System (RAMS) over a range of simulated classification accuracies
over a 3 month period. This study found that land cover accuracy under
80% had a strong effect on precipitation especially when the land surface
had a greater control of the atmosphere. This effect became stronger
as the accuracy decreased. As shown in three follow-on experiments,
the effect was further influenced by model parameterizations such as
convection schemes and interior nudging, which can mitigate the strength
of surface boundary forcings. In reality, land cover accuracy rarely
obtains the commonly recommended 85% target. Its effect on climate simulations
should therefore be considered, especially when historically reconstructed
and future projected land covers are employed.
Ge, Z., and P.C. LIU. A time-localized response of
wave growth process under turbulent winds. Annales Geophysicae
25:1253-1262 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070018.pdf
Very short time series (with lengths of approximately 40 s or 5-7
wave periods) of wind velocity fluctuations and wave elevation were
recorded simultaneously and investigated using the wavelet bispectral
analysis. Rapid changes in the wave and wind spectra were detected,
which were found to be intimately related to significant energy transfers
through transient quadratic wind-wave and wave wave-induced interactions.
A possible pattern of energy exchange between the wind and wave fields
was further deduced. In particular, the generation and variation of
the strong wave-induced perturbation velocity in the wind can be explained
by the strengthening and diminishing of the associated quadratic interactions,
which cannot be unveiled by linear theories. On small time scales, the
wave-wave quadratic interactions were as active and effective in transferring
energy as the wind-wave interactions. The results also showed that the
wind turbulence was occasionally effective in transferring energy between
the wind and the wave fields, so that the background turbulence in the
wind cannot be completely neglected. Although these effects are all
possibly significant over short times, the time-localized growth of
the wave spectrum may not considerably affect the long-term process
of wave development.
Godby, N.A., Jr., E.S. Rutherford, and D.M. MASON.
Diet, feeding rate, growth, mortality, and production of juvenile steelhead
in a Lake Michigan tributary. North American Journal of Fisheries
Management 27:578-592 (2007).
http://www.glerl.noaa.gov/pubs/fulltext/2007/20070009.pdf
Steelhead (Oncorhynchus mykiss) support valuable sport fisheries
in the Great Lakes but are largely sustained by stocking. In many Great
Lakes tributaries, steelhead spawning and nursery habitats are limited
by hydropower dams, and natural recruitment may be supplemented by habitats
in adjacent coldwater creeks. In 1998–2001, we investigated the
potential for natural production of steelhead in the Muskegon River,
Michigan, a tributary to Lake Michigan, through analysis of parr diet
categories, consumption, growth, survival, and production in the main-stem
Muskegon River and in Bigelow Creek. We used electrofishing surveys
to estimate parr growth and survival from changes in fish weight and
density over time. We estimated diet from gut content analysis and consumption
from bioenergetics model analysis. Average fall density of parr in Bigelow
Creek was 20-fold higher than in the Muskegon River. Average summer
daily mortality rate of parr in the Muskegon River was nearly threefold
higher than in Bigelow Creek. Overwinter mortality rates of parr were
low in both habitats. Few yearling and older parr were present in the
Muskegon River relative to Bigelow Creek. Age-0 parr primarily consumed
benthic invertebrates. Macroinvertebrate prey densities were sufficient
to support high parr growth rates in both rivers. Parr grew at similar
rates but consumed 84% more per day in the Muskegon River, which had
higher water temperatures than Bigelow Creek. Age-0 production was fivefold
higher in Bigelow Creek than in the Muskegon River. High mortalities
of parr in the Muskegon River were correlated with summer water temperatures
exceeding 21oC. Average summer temperatures in Bigelow Creek (17oC)
were optimal for parr survival. Our results were consistent with data
from other Great Lakes tributaries and suggest that small tributary
creek habitats contribute disproportionately to steelhead recruitment
from large impounded watersheds by providing optimal thermal refugia
for parr during summer.
Great Lakes Beach Association, NOAA Great Lakes Environmental
Research Laboratory, Michigan Sea Grant Program, U.S. Environmental
Protection Agency, and U.S. Geological Survey. Great Lakes
beach health research needs: Workshop summary. NOAA Technical Memorandum
GLERL-138. NOAA, Great Lakes Environmental Research Laboratory, Ann
Arbor, MI, 27 pp. (2006). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-138/tm-138.pdf
The Great Lakes coastline is the largest in the continental United
States, containing hundreds of beaches and providing recreational opportunities
for millions of visitors, thus making it a vital part of the Midwest
economy. Too often the health of these beaches is compromised by water
quality degradation particularly from the introduction of sewage and
accompanying pathogens. These events, whether chronic or episodic, not
only reduce the quality of recreation but threaten human health. Public
officials responsible for protecting natural resources and visitor health
seek ways to remediate these problems and to communicate any health
threats in a timely manner. Increasingly sophisticated scientific information
is required to provide solutions to these problems not only for the
Great Lakes but along coastlines worldwide.
He, C., and T. E. CROLEY II. Application of a distributed
large basin runoff model in the Great Lakes basin. Control Engineering
Practice 15:1001-1011 (2007).
This paper analyzes the application of a spatially distributed large
basin runoff model (DLBRM) in the Great Lakes Basin of the United States
and Canada and discusses four essential components of operational hydrologic
model development: model structure, model input, model calibration,
and Geographical Information System (GIS)-model interface. The results
indicate that large scale operational hydrologic models that are based
on mass continuity equations and include land surface, soil zones, and
groundwater components require fewer parameters, are less data demanding,
and are particularly suitable for solving water resources problems over
large spatial and temporal scales than many other models. Use of GIS-model
interfaces is essential for utilizing the existing multiple digital
databases in defining model input and in facilitating model implementation
and applicability.
Holker, F., H. Dorner, T. Schulze, S. S. Haertel-Borer, S.D.
PEACOR, and T. Mehner. Species-specific responses of planktivorous
fish to the introduction of a new piscivore: implications for prey fitness.
Freshwater Biology 52(doi:10.1111/j.1365-2427.2007.01810.x):1793-1806
(2007).
1. Antipredator behaviour by the facultative planktivorous fish species
roach (Rutilus rutilus), perch (Perca fluviatilis)
and rudd (Scardinius erythrophthalmus) was studied in a multi-year
whole-lake experiment to evaluate species-specific behavioural and numerical
responses to the stocking of pikeperch (Sander lucioperca),
a predator with different foraging behaviour than the resident predators
large perch (P. fluviatilis) and pike (Esox lucius).
2. Behavioural responses to pikeperch varied greatly during the night,
ranging from reduced activity (roach and small perch) and a shift in
habitat (roach), to no change in the habitat use and activity of rudd.
The differing responses of the different planktivorous prey species
highlight the potential variation in behavioural response to predation
risk from species of similar vulnerability.
3. These differences had profound effects on fitness; the density of
species that exhibited an antipredator response declined only slightly
(roach) or even increased (small perch), whereas the density of the
species that did not exhibit an antipredator response (rudd) decreased
dramatically (by more than 80%).
4. The maladaptive behaviour of rudd can be explained by a ‘behavioural
syndrome’, i.e. the interdependence of behaviours expressed in
different contexts (feeding activity, antipredator) across different
situations (different densities of predators).
5. Our study extends previous studies, that have typically been limited
to more controlled situations, by illustrating the variability in intensity
of phenotypic responses to predators, and the consequences for population
density, in a large whole-lake setting.
Holloway, G., F. Dupont, E. Golubeva, S. Hakkinen, E. Hunke,
M. Jin, M. Karcher, F. Kauker, M. Maltrud, M. A. Morales-Maqueda, W.
Maslowski, G. Platov, D. Stark, M. Steele, T. Suzuki, J. WANG, and J.
Zhang. Water properties and circulation in Arctic Ocean models.
Journal of Geophysical Research 112(C04503, doi: 10.1029/2006JC003642):18
pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070031.pdf
[1] As a part of the Arctic Ocean Model Intercomparison Project, results
from 10 Arctic ocean/ice models are intercompared over the period 1970
through 1999. Models’ monthly mean outputs are laterally integrated
over two subdomains (Amerasian and Eurasian basins), then examined as
functions of depth and time. Differences in such fields as averaged
temperature and salinity arise from models’ differences in parameterizations
and numerical methods and from different domain sizes, with anomalies
that develop at lower latitudes carried into the Arctic. A systematic
deficiency is seen as AOMIP models tend to produce thermally stratified
upper layers rather than the ‘‘cold halocline’’,
suggesting missing physics perhaps related to vertical mixing or to
shelf-basin exchanges. Flow fields pose a challenge for intercomparison.
We introduce topostrophy, the vertical component of Vx?D where V is
monthly mean velocity and ?D is the gradient of total depth, characterizing
the tendency to follow topographic slopes. Positive topostrophy expresses
a tendency for cyclonic ‘‘rim currents’’. Systematic
differences of models’ circulations are found to depend strongly
upon assumed roles of unresolved eddies.
HÖÖK, T.O., M.J. McCORMICK, E.S. Rutherford, D.M.
MASON, and G.S. Carter. Short-term water mass movements in
Lake Michigan: Implications for larval fish transport. Journal of Great
Lakes Research 32:728-737 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060044.pdf
Water mass movement within the Great Lakes may rapidly transport fish
larvae from favorable nursery areas to less favorable habitats, thereby
affecting recruitment success. During 2001 and 2002, we released satellite-tracked
drifting buoys in eastern Lake Michigan to follow discrete water masses,
and used ichthyoplankton nets to repeatedly sample larval fish within
these water masses. Observed nearshore water currents were highly variable
in both direction and velocity. Current velocities far exceeded potential
larval fish swimming speeds, suggesting that currents can potentially
rapidly advect fish larvae throughout the lake. Evidence suggests that
while paired drifters released during 2002 were able to track relatively
small alewife (Alosa pseudoharengus) and yellow perch (Perca
flavescens) larvae within an alongshore coastal current, paired
drifters released during 2001 failed to track larger alewife larvae
when flow was more offshore and highly variable. These results are consistent
with the decorrelation scales associated with alongshore and offshore
transport.
HÖÖK, T.O., E.S. Rutherford, D.M. MASON, and G.S.
Carter. Hatch dates, growth rates, and over-winter mortality
of age-0 alewives in Lake Michigan: Implications for habitat-specific
recruitment success. Transactions of the American Fisheries Society
136:1298-1312 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070028.pdf
Alewives, Alosa pseudoharengus, are key components of Laurentian
Great Lakes ecosystems and spawn in multiple habitat types. Exploration
of alewife early life history dynamics within these different habitats
should help identify important recruitment processes. During 2001–2003,
we quantified physical (temperature, transparency) and biotic (chlorophyll
a, zooplankton densities) habitat factors and collected age-0 alewives
(using ichthyoplankton nets and trawls) in a nearshore region of Lake
Michigan and Muskegon Lake, Michigan (a drowned river mouth lake connected
to Lake Michigan). We characterized alewife hatch dates, individual
condition, growth, mortality, and size-dependent overwinter survival
to infer differences in habitat-specific recruitment success. Temperature,
turbidity, chlorophyll-a concentrations, and densities of zooplankton
prey were consistently higher in Muskegon Lake than in nearshore Lake
Michigan. On average, young alewives in Muskegon Lake hatched earlier,
grew faster, were in better condition (based on a biphasic length–weight
relationship), and had greater survival than alewives in Lake Michigan.
By the end of the growing season, young alewives in Muskegon Lake obtained
a larger size than those residing in nearshore Lake Michigan, suggesting
that they were more likely to survive through winter (a period of intense
size-selective mortality) and ultimately recruit to the adult population.
Jin, M., C. Deal, J. WANG, V. Alexander, R. Gradinger, S. Saitoh,
T. Iida, Z. Wan, and P. Stabeno. Ice-associated phytoplankton
blooms in the southeastern Bering Sea. Geophysical Research Letters
34(L06612, doi:10.1029/2006GL028849):6 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070025.pdf
Ice-associated phytoplankton blooms in the southeastern Bering Sea
can critically impact the food web structure, from lower tropic level
production to marine fisheries. By coupling pelagic and sea ice algal
components, our 1-D ecosystem model successfully reproduced the observed
ice-associated blooms in 1997 and 1999 at the NOAA/PMEL mooring M2.
The model results suggest that the ice-associated blooms were seeded
by sea ice algae released from melting sea ice. For an ice-associated
bloom to grow and reach the typical magnitude of phytoplankton bloom
in the region, ice melting-resulted low-salinity stratification must
not be followed by a strong mixing event that would destroy the stratification.
The ice-associated blooms had little impacts on the annual primary production,
but had significant impacts in terms of shifting phytoplankton species,
and the timing and magnitude of the bloom. These changes, superimposed
on a gradual ecosystem shift attributed to global warming, can dramatically
alter the Bering Sea ecosystem.
KASHIAN, D.R., R. E. Zuellig, K.A. Mitchell, and W H. Clements.
The cost of tolerance: Sensitivity of stream benthic communities to
UV-B and metals. Ecological Applications 17(2):365-375 (2007).
http://www.glerl.noaa.gov/pubs/fulltext/2007/20070030.pdf
The ability to tolerate disturbance is a defense strategy that minimizes
the effects of damage to fitness and is essential for sustainability
of populations, communities, and ecosystems. Despite the apparent benefits
of tolerance, there may be an associated cost that results in a deficiency
of a system to respond to additional disturbances. Aquatic ecosystems
are often exposed to a variety of natural and anthropogenic disturbances,
and the effects of these compound perturbations are not well known.
In this investigation, we examine whether tolerance to one stressor,
metals, results in a cost of increased sensitivity to an additional
stressor, ultraviolet-B (UV-B) radiation.
Heavy metal pollution is recognized as a major environmental problem
in Rocky Mountain streams. These high-elevation, typically clear streams
may be at particular risk to elevated UVB levels associated with reduced
levels of ozone. Microcosm experiments were conducted using natural
stream benthic communities collected from a reference site and a site
with a long-term history of heavy-metal pollution. Direct and interactive
effects of heavy metals and UV-B radiation on structural and functional
characteristics of benthic communities were evaluated among four treatments:
control, UV-B, metals, and metal and UV-B. Communities from the metal-polluted
site were more tolerant of metals but less tolerant to UV-B compared
to reference communities. Increased mayfly drift and reduced metabolism
in response to metal exposure were observed in reference communities
but not in the metal-polluted communities. In contrast to these results,
UV-B radiation significantly reduced community metabolism, total macroinvertebrate
abundance, and abundances of mayflies, caddisflies, and dipterans from
the metal-polluted site, but had no effects on benthic communities from
the reference site. ANOSIM results demonstrated that community responses
differed among treatments at both sites. Metals had the largest impact
on community differences at both sites, while UV-B had greater impacts
at the metal-polluted site. This research demonstrates the need to account
for potential costs associated with tolerance and that these costs can
result in behavioral, structural, and functional impacts to benthic
communities.
Kelley, J.G.W., P. Chu, A.-J. Zhang, and G.A. LANG.
Skill assessment of NOS Lake Superior Operational Forecast System (LSOFS).
NOAA Technical Memorandum NOS CS 9. NOSS Office of Coast Survey, Coast
Survey Development Lab, Silver Spring, MD, 48 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/2007tmNOS_CS9.pdf
This document describes the Lake Superior Operational Forecast System
(LSOFS) and an assessment of its skill. The lake forecast system, based
on a hydrodynamic model, uses near real-time atmospheric observations
and numerical weather prediction forecast guidance to produce three-dimensional
forecast guidance of water temperature and currents and two-dimensional
forecasts of water levels for Lake Superior. LSOFS is the result of
technology transfer of the Great Lake Forecasting System (GLFS) and
Great Lakes Coastal Forecasting System (GLCFS) from The Ohio State University
(OSU) and NOAA’s Great Lakes Environmental Research Laboratory
(GLERL) to NOAA’s National Ocean Service.
Kelley, J G.W., P. Chu, A.-J. Zhang, G.A. LANG, and D.J. SCHWAB.
Skill assessment of NOS Lake Michigan Operational Forecast System (LMOFS).
NOAA Technical Memorandum NOS CS 8. NOAA, Office of Coast Survey, Coast
Survey Development Laboratory, Silver Spring, MD, 67 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/2007tmNOS_CS8.pdf
This document describes the Lake Michigan Operational Forecast System
(LMOFS) and an assessment of its skill. The lake forecast system, based
on a hydrodynamic model, uses near real-time atmospheric observations
and numerical weather prediction forecast guidance to produce three-dimensional
forecast guidance of water temperature and currents and two-dimensional
forecasts of water levels for Lake Michigan. LMOFS is the result of
technology transfer of the Great Lake Forecasting System (GLFS) and
Great Lakes Coastal Forecasting System (GLCFS) from The Ohio State University
(OSU) and NOAA’s Great Lakes Environmental Research Laboratory
(GLERL) to NOAA’s National Ocean Service.
Lee, C., D.J. SCHWAB, D. BELETSKY, J. Stroud, and B.M. Lesht.
Numerical modeling of mixed sediment resuspension, transport, and deposition
during the March 1998 episodic events in southern Lake Michigan. Journal
of Geophysical Research 112(C02018, doi:10.1029/2005JC003419):17
pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070011.pdf
A two-dimensional sediment transport model capable of simulating sediment
resuspension of mixed (cohesive plus noncohesive) sediment is developed
and applied to quantitatively simulate the March 1998 resuspension events
in southern Lake Michigan. Some characteristics of the model are the
capability to incorporate several floc size classes, a physically based
settling velocity formula, bed armoring, and sediment availability limitation.
Important resuspension parameters were estimated from field and laboratory
measurement data. The model reproduced the resuspension plume (observed
by the SeaWIFS satellite and field instruments) and recently measured
sedimentation rate distribution (using radiotracer techniques) fairly
well. Model results were verified with field measurements of suspended
sediment concentration and settling flux (by ADCPs and sediment traps).
Both wave conditions and sediment bed properties (critical shear stress,
fine sediment fraction, and limited sediment availability or source)
are the critical factors that determine the concentration distribution
and width of the resuspension plume. The modeled sedimentation pattern
shows preferential accumulation of sediment on the eastern side of the
lake, which agrees with the observed sedimentation pattern despite a
predominance of particle sources from the western shoreline. The main
physical mechanisms determining the sedimentation pattern are (1) the
two counter-rotating circulation gyres producing offshore mass transport
along the southeastern coast during northerly wind, and (2) the settling
velocity of sediment flocs which controls the deposition location.
LESHKEVICH, G.A., and S.V. Nghiem. Algorithm development
for operational satellite SAR classification and mapping of Great Lakes
ice cover. Proceedings, OceanSAR 2006 - Third Workshop on Coastal and
Marine Applications of SAR, St. John's, Newfoundland, Canada, October
25, 2006. 3 pp. (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060051.pdf
During the 1997 winter season, shipborne polarimetric backscatter
measurements of Great Lakes (freshwater) ice types using the Jet Propulsion
Laboratory (JPL) C-band scatterometer, together with surface-based ice
physical characterization measurements and environmental parameters
were acquired. This polarimetric data set, measured at incident angles
from 0o to 60o for all polarizations, was processed to radar cross-section
to establish a library of signatures (look-up table) for different ice
types. Using this library of signatures, computer analysis of calibrated
ERS-2 and RADARSAT ScanSAR images of Great Lakes ice cover using a supervised
classification technique indicates that different ice types in the ice
cover can be identified and mapped, and that wind speed and direction
can have an influence on the classification of water as ice based on
single frequency, single polarization data.
LIU, P.C. A chronology of freaque wave encounters.
Geofizika 24(1):57-70 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070019.pdf
Freaque waves is a newly coined term that combines the two common
synonymously used terms of rogue and freak waves. Long before the recent
sweeping recognition of the existence of freaque waves, stories of encounters
with the unexpected and unusually large waves in the ocean have been
told and proffered among seafarers throughout the ages. After being
ignored or dismissed for decades, freaque waves have now emerged as
an apropos oceanographic research subject. The current literature consists
of various conjectured mechanisms aimed at explaining some aspects for
the occurrence of freak waves. Examples are: the linear or nonlinear
superposition of waves that lead to larger instability and wave heights,
and the focusing of wave energy through time and space, through areas
of variable surface ocean currents, and through nonlinear systems such
as various attributes of the nonlinear Schrodinger equation. These diversified
theoretical postulations mainly demonstrate that it is possible to simulate
some wave profiles that might resemble the appearance of freaque waves.
At the present, however, none of these conjectures can be readily substantiated
by measurements or shed new light on how a freak wave can be recognized
before its encounter. There is not even an available universal definition
for freaque waves beyond the simple rule of thumb of a height greater
than twice the significant wave height. Contrary to some claims, freaque
waves are presently not predictable. The following compilation is an
attempt to create a chronology of some of the most-well-known or reliably
reported freaque wave encounters, along with their respective, relevant,
and easily accessible sources. Each case is generally composed of year,
date, location, name of the vessel, a brief description of the encounter,
and extent of damages if known. While efforts have been made to incorporate
all known cases of freaque waves that were witnessed, alleged, or adverted
to, clearly no premise of accuracy or completeness can be vouched for
here. Additions, corrections, and modifications are sincerely welcome.
LIU, P.C., C.-H. Tsai, and H.S. Chen. On the growth
of ocean waves. Ocean Engineering 34:1472-1480 (2007).
The availability of 10 h of continuous, uninterrupted field measurements
of wind waves recorded in the western Pacific and containing a complete
wave growth episode, has provided a distinct opportunity for us to make
a novel, unprecedented examination of detailed wave growth processes.
We found that the significance of the size of data used in the measurement,
which can only be addressed with continuous and uninterrupted measurements,
reflected the ineptness of the conventional approach toward further
detailed understanding of realistic wave growth processes, as the conventional
20 min data size essentially stamped out any dynamics with time scale
below 20 min. While our conventional understanding and modeling were
generally operative and useful, they left no real vestige on time localized
mechanisms such as wave grouping or wave breaking processes all with
time scales much less than 20 min.
LOFGREN, B.M. Land surface roughness effects on lake
effect precipitation. Journal of Great Lakes Research 32:839-851
(2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060045.pdf
The land use of the Great Lakes region has changed significantly during
historical times, and continues to change. As a preliminary step in
investigating the overall effect that this might have on climate, attention
is focused here on one forcing factor and one effect—land surface
roughness length and lake effect precipitation, respectively—that
are anticipated to be particularly sensitive pieces of the land use-climate
interaction. On both a monthly basis and in an individual case of lake
effect precipitation, a reduction of land surface roughness reduces
the total amount of lake effect precipitation. It also reduces the degree
to which the precipitation is focused on the area closest to the lakeshore.
The largest reductions occur immediately adjacent to the lakeshore in
an area smaller than the overall lake effect zone. In the individual
lake effect event that is investigated here, precipitation increases
in some places farther inland when surface roughness is reduced. Because
this increase in precipitation farther inland appears to be associated
with significant topography, this result is most valid for lake effect
zones where there is a high topographic relief, such as near southeastern
Lake Erie (the main focus of this study), and to the south and east
of Lake Ontario. This displacement in location of precipitation is particularly
crucial where the boundary of the drainage basin is near the shoreline,
and can indicate a flux of moisture out of the Great Lakes drainage
basin and into another basin.
LUDSIN, S. A., C. H. HAND, J. E. Marsden, B. J. Fryer, and
E. A. Howe. Micro-elemental analysis of statoliths as a tool
for tracking tributary origins of sea lamprey. 2006 Project Completion
Report, Great Lakes Fishery Commission, Ann Arbor, MI, 106 pp. (2006).
http://www.glerl.noaa.gov/pubs/fulltext/2006/20060046.pdf
The analysis of otolith micro-elemental composition has been a valuable
tool for differentiating among local spawning populations, and identifying
origins of recruits to the fishery. Herein, we explored whether the
analysis of sea lamprey (Petromyzon marinus) statolith micro-elemental
composition by laser-ablation inductively-coupled plasma-mass spectrometry
(LA-ICP-MS) could be used as a tool to 1) discriminate among sea lamprey
larvae collected from Lake Huron tributaries, and 2) classify a mixed-sample
of unknown-origin parasites or spawners back to their natal source.
By providing the GLFC with an alternate means, to labor-intensive tagging
studies, to determine relative contributions of parasites and spawners
from various spawning tributaries, we sought to enhance the GLFC’s
ability to prioritize sea lamprey control efforts. As part of this effort,
we analyzed statoliths of larvae collected in 45 Lake Huron tributaries
during 2004 and 2005, as well as 72 female spawners collected in the
Thessalon and Opequeoc rivers during 2005. Our analyses were conducted
at three different classification scales: by geologic zone (n = 4 zones),
by watershed (n = 9 watersheds), and by individual stream (n = 45 streams).
Similar to a previous GLFC pilot study conducted using Proton Induced
X-ray Emission (PIXE), we found that LA-ICP-MS analysis of statolith
micro-elemental composition could be used to reliably differentiate
among individuals produced in different regions (i.e., geologic zones,
watersheds, streams), with the level of successful discrimination varying
with classification scale. Regardless of the scale of classification,
rubidium (Rb), strontium (Sr), manganese (Mn), and barium (Ba) were
always most important for discrimination, with zinc (Zn), magnesium
(Mg), and lead (Pb) being less useful. Analysis of water and sediment
samples from 31 Lake Huron and Lake Champlain tributaries helps to understand
these differences in utility for discrimination in that concentrations
of Rb, Sr, Mn, and Ba in larval statoliths and ambient water were correlated,
whereas concentrations of Zn, Mg, and Pb were not. Analysis of left-right
statolith pairs also demonstrate that Zn, Mg, and Pb were not analytically
stable in our analyses for reasons that are not entirely clear. Ultimately,
using Rb, Sr, Mn, and Ba in maximum-likelihood estimation analyses conducted
on a mixed-stock of adult spawners collected in 2005, we found that
the sources contributing the greatest proportion of adults to our mixed
sample were: 1) the Southern Lake Superior geologic zone (located north
of Lake Huron); 2) the Wanipiti-French watershed; and 3) Beavertail
Creek, Mississagi River, Lauzon Creek, Garden River, and Musquash River.
However, these results need to be viewed with some caution, given our
lack of success in accurately typing a sample of known-origin (tagged)
spawners back to their natal streams in parallel study conducted in
Lake Champlain. In discussing these results, we identify analytical
and research needs that could further support our findings, and advance
the use of statolith microchemistry as a means to identify natal origins
of parasitic and adult sea lamprey in Lake Huron.
MacHutchon, K.R., and P.C. LIU. Measurement and analysis
of ocean wave fields in four dimensions. Proceedings of the 26th International
Conference on Offshore Mechanics and Arctic Engineering, OMAE2007, San
Diego, CA, June 10-15, 2007. 5 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070017.pdf
Ocean wave data comprises either instrumentally-measured data or model-derived
data, and the former type of data is preferred in the offshore industry.
Instrumental data can be considered to be comprised of both directly
measured sea surface displacement data and derived data, from the acceleration
of buoys. It has been found that significant differences can occur between
sea surface displacements, which are recorded in steep waves by fixed
probes or lasers (Eulerian), or by free-floating buoys (Lagrangian).
This has given rise to the situation where wave buoy data should not
be used to estimate wave profiles in steep waves. Short crested and
heaped waves, in moderate to high sea states, can also cause a problem
when recording wave data at a fixed point, when it comes to determining
the representivity of the results across a wave field. Recorded wave
data is used as the basis for the development as well as the verification
of all wave models and, given the above uncertainties, the authors propose
a new wave measurement method, using the recently developed Automated
Trinocular Stereo Imaging System (ATSIS), for the recording of three-dimensional
surface wave displacements with respect to time. The ATSIS is a novel
system, which measures the temporal evolution of three- dimensional
wave characteristics for analysis. An oblique configuration for the
system effectively increases spatial coverage, allowing observations
of wave phenomena over a broad range of temporal and spatial scales.
The details in the paper provide a solution of quantifying the behaviour
of irregular, non-linear, and directionally spread (short crested waves),
and provides an efficient method for developing better design criteria
in the future.
MASON, D.M., B. Nagy, M. Butler, S. Larsen, D.J. Murie, and
W.J. Lindberg. Integration of technologies for understanding
the functional relationship between reef habitat and fish growth and
production. In Emerging Technologies for Reef Fisheries Research
and Management. J.C. Taylor (Ed.). NOAA Professional Paper NMFS
No. 5. NOAA National Marine Fisheries Service, Seattle, WA, 105-116
(2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060047.pdf
Functional linkage between reef habitat quality and fish growth and
production has remained elusive. Most current research is focused on
correlative relationships between a general habitat type and presence/absence
of a species, an index of species abundance, or species diversity. Such
descriptive information largely ignores how reef attributes regulate
reef fish abundance (density-dependent habitat selection), trophic interactions,
and physiological performance (growth and condition). To determine the
functional relationship between habitat quality, fish abundance, trophic
interactions, and physiological performance, we are using an experimental
reef system in the northeastern Gulf of Mexico where we apply advanced
sensor and biochemical technologies. Our study site controls for reef
attributes (size, cavity space, and reef mosaics) and focuses on the
processes that regulate gag grouper (Mycteroperca mscrolepis)
abundance, behavior and performance (growth and condition), and the
availability of their pelagic prey. We combine mobile and fixed-active
(fisheries) acoustics, passive acoustics, video cameras, and advanced
biochemical techniques. Fisheries acoustics quantifies the abundance
of pelagic prey fishes associated with the reefs and their behavior.
Passive acoustics and video allow direct observation of gag and prey
fish behavior and the acoustic environment, and provide a direct visual
for the interpretation of fixed fisheries acoustics measurements. New
application of biochemical techniques, such as Electron Transport System
(ETS) assay, allow the in situ measurement of metabolic expenditure
of gag and relates this back to reef attributes, gag behavior, and prey
fish availability. Here, we provide an overview of our integrated technological
approach for understanding and quantifying the functional relationship
between reef habitat quality and one element of production - gag grouper
growth on shallow coastal reefs.
Moisander, P.H., H.W. Paerl, J. DYBLE, and K. Sivonen.
Phosphorus limitation and diel control of nitrogen-fixing cyanobacteria
in the Baltic Sea. Marine Ecology Progress Series 345:41-50
(2007).
Up to half of the annual new nitrogen inputs into the Baltic Sea originate
from blooms of N2-fixing cyanobacteria. Estimates of the magnitude of
this new nitrogen vary, partially because relatively few studies have
investigated short-term changes in N2-fixation rates in response to
environmental changes in situ, including phosphorus availability, one
of the major factors limiting N2 fixation in the system. We examined
cyanobacterial N2 fixation in response to phosphorus amendments over
the diel cycle during 2002 and 2003 in the Baltic Sea, when both Nodularia
spumigena and Aphanizomenon sp. formed blooms. Phosphorus
stimulated N2 fixation in the open-sea areas in the Northern Baltic
Proper and Gulf of Finland during both years. In microcosm experiments,
both chlorophyll a concentration and N2 fixation were positively related
to time (R2 = 0.79 and 0.54, respectively) for at least 4.5 d after
the P amendment. N2 fixation was enhanced up to 3-fold within 4.5 d
by a single P pulse. N2 fixation continued in the dark at 16 to 61%
of maximum rates during the day, and there were no consistent changes
in nitrogenase enzyme abundance in response to darkness. Immunoblotting
showed that N2 fixation is not regulated in response to darkness by
size modifications of the Fe and MoFe proteins in N. spumigena or
of the Fe protein of Aphanizomenon sp. Capability to fix N2
at high rates at night allows these cyanobacteria to maximize their
utilization of periodic P pulses for subsequent growth.
NALEPA, T.F., D.L. FANSLOW, S.A. POTHOVEN, A.J. FOLEY III,
and G.A. LANG. Long-term trends in benthic macroinvertebrate
populations in Lake Huron over the past four decades. Journal of
Great Lakes Research 33(2):421-436 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070020.pdf
Surveys of the benthic macroinvertebrate community were conducted
in the main basin of Lake Huron in 2000 and 2003, and in Georgian Bay
and North channel in 2002. Results were compared to surveys conducted
in the 1960s and early 1970s. Although data of earlier surveys were
inconsistent, our best estimates suggest that total density of the four
major benthic taxa (Diporeia spp., Oligochaeta, Sphaeriidae,
and Chironomidae) in the main basin declined dramatically between the
early 1970s and 2000. Populations of all major taxa continued to decline
between 2000 and 2003, particularly Diporeia and Sphaeriidae.
Diporeia was rare or absent in the southern end of the lake
and in some nearshore areas in 2000, and by 2003 was not found at depths
< 50 m except in the far northeastern end of the lake. Densities
of the major taxa in Georgian Bay and North Channel in 2002 were not
different from densities in 1973 despite differences in survey methods.
A limited study in southern Georgian Bay, however, found that densities
of both Diporeia and Sphaeriidae declined to zero at most sites
between 2000 and 2004. The population of Dreissena polymorpha
was stable in all lake areas, but Dreissena bugensis
increased, particularly at the 31–50 m depth interval in the main
basin. Since there were no extensive surveys in Lake Huron in the period
between nutrient abatement (late 1970s) and the establishment of Dreissena
(early 1990s), it is difficult to determine relative roles of these
events on observed declines. However, since phosphorus loads have been
stable since the early 1980s, declines between 2000 and 2003 can likely
be attributed to Dreissena.
NALEPA, T.F., D.L. FANSLOW, S.A. POTHOVEN, A.J. FOLEY III,
G.A. LANG, S.C. Mozley, and M.W. Winnell. Abundance and distribution
of benthic macroinvertebrate populations in Lake Huron in 1972 and 2000-2003.
NOAA Technical Memorandum GLERL-140. NOAA, Great Lakes Environmental
Research Laboratory, Ann Arbor, MI, 33 pp. (2007). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-140/tm-140.pdf
This technical report gives results of benthic macroinvertebrate surveys
conducted in Lake Huron between 2000 and 2003, and in 1972. Objectives
of the former surveys were to document the status of benthic communities,
and to assess changes over time. Over the past 20-30 years, the benthic
community of Lake Huron has been the least studied of all the Great
Lakes. While a number of benthic surveys were conducted in Lake Huron
in the early 1970s (Schelske and Roth 1972; Shrivastava 1974; Loveridge
and Cook 1976; Great Lakes Research Division-University of Michigan,
unpublished data), no wide-scale surveys have been conducted in the
lake since this time period. With broad changes now occurring in many
of the other Great Lakes because of phosphorus abatement and the introduction
of invasive species, an assessment of the benthic community in Lake
Huron is both timely and needed. Of particular interest is the status
of the benthic amphipod Diporeia spp. This ecologically-important
organism has declined dramatically in Lakes Erie, Michigan, and Ontario
(Dermott and Kerec 1997, Nalepa et al. 1998, Lozano et al 2001, Nalepa
et al 2006) since the introduction and spread of Dreissena
polymorpha (zebra mussel) and Dreissena bugensis
(quagga mussel), and information is needed to determine if similar declines
have occurred in Lake Huron.
PANGLE, K.L., S.D. PEACOR, and O.E. Johansson. Large
nonlethal effects of an invasive invertebrate predator on zooplankton
population growth rate. Ecology 88(2):402-412 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070005.pdf
We conducted a study to determine the contribution of lethal and nonlethal
effects to a predator’s net effect on a prey’s population
growth rate in a natural setting. We focused on the effects of an invasive
invertebrate predator, Bythotrephes longimanus, on zooplankton
prey populations in Lakes Michigan and Erie. Field data taken at multiple
dates and locations in both systems indicated that the prey species
Daphnia mendotae, Daphnia retrocurva, and Bosmina
longirostris inhabited deeper portions of the water column as Bythotrephes
biomass increased, possibly as an avoidance response to predation. This
induced migration reduces predation risk but also can reduce birth rate
due to exposure to cooler temperatures. We estimated the nonlethal (i.e.,
resulting from reduced birth rate) and lethal (i.e., consumptive) effects
of Bythotrephes on D. mendotae and Bosmina longirostris.
These estimates used diel field survey data of the vertical gradient
of zooplankton prey density, Bythotrephes density, light intensity,
and temperature with growth and predation rate models derived from laboratory
studies. Results indicate that nonlethal effects played a substantial
role in the net effect of Bythotrephes on several prey population
growth rates in the field, with nonlethal effects on the same order
of magnitude as or greater (up to 10-fold) than lethal effects. Our
results further indicate that invasive species can have strong nonlethal,
behaviorally based effects, despite short evolutionary coexistence with
prey species.
PEACOR, S.D. Behavioural response of bullfrog tadpoles
to chemical cues of predation risk are affected by cue age and water
source. Hydrobiologia 573:39-44 (doi 10.1007/s10750-006-0256-3)
(2006).
When confronted by signals of predators presence, many aquatic organisms
modify their phenotype (e.g., behaviour or morphology) to reduce their
risk of predation. A principal means by which organisms assess predation
risk is through chemical cues produced by the predators and/or prey
during predation events. Such responses to predation risk can directly
affect prey fitness and indirectly affect the fitness of species with
which the prey interacts. Accurate assessment of the cue will affect
the adaptive nature, and hence evolution, of the phenotypic response.
It is therefore, important to understand factors affecting the assessment
of chemical cues. Here I examined the effect of the age of chemical
cues arising from an invertebrate predator, a larval dragonfly (Anax
junius), which was fed bullfrog tadpoles, on the behavioural response
(activity level and position) of bullfrog tadpoles. The bullfrog response
to chemical cues declined as a function of chemical cue age, indicating
the degradation of the chemical cue was on the order of 2–4 days.
Further, the decay occurred more rapidly when the chemical cue was placed
in pond water rather than well water. These results indicate a limitation
of the tadpoles to interpret factors that affect the magnitude of the
chemical cue and hence accurately assess predation risk. These findings
also have implications for experimental design and the adaptation of
phenotypic responses to chemical cues of predation risk.
PEACOR, S.D., J. R. Bence, and C.A. Pfister. The effect
of size-dependent growth and environmental factors on animal size variability.
Theoretical Population Biology 71(2007):80-94 (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060040.pdf
The origin of variation in animal growth rate and body size is not
well understood but central to ecological and evolutionary processes.
We develop a relationship that predicts the change in relative body
size variation within a cohort will be approximately equal to the relative
change in mean per unit size growth rate, when only size-dependent factors
affect growth. When modeling cohort growth, relative size variation
decreased, remained unchanged, or increased, as a function of growth
rate-size scaling relationships, in a predictable manner. We use the
approximation to predict how environmental factors (e.g., resource level)
affect body size variation, and verified these predictions numerically
for a flexible growth model using a wide range of parameter values.
We also explore and discuss the assumptions underlying the approximation.
We find that factors that similarly affect mean growth rate may differently
affect size variation, and competition may increase body size variation
without changing size-independent relationships. We discuss implications
of our results to the choice of growth equations used in models where
body size variation is an important variable or output.
PEACOR, S.D., S. Allesina, R L. Riolo, and M. Pascual.
Phenotypic plasticity opposes species invasions by altering fitness
surface. PLoS Biology 4(11):9 pp. (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060038.pdf
Understanding species invasion is a central problem in ecology because
invasions of exotic species severely impact ecosystems, and because
invasions underlie fundamental ecological processes. However, the influence
on invasions of phenotypic plasticity, a key component of many species
interactions, is unknown. We present a model in which phenotypic plasticity
of a resident species increases its ability to oppose invaders, and
plasticity of an invader increases its ability to displace residents.
Whereas these effects are expected due to increased fitness associated
with phenotypic plasticity, the model additionally reveals a new and
unforeseen mechanism by which plasticity affects invasions: phenotypic
plasticity increases the steepness of the fitness surface, thereby making
invasion more difficult, even by phenotypically plastic invaders. Our
results should apply to phenotypically plastic responses to any fluctuating
environmental factors including predation risk, and to other factors
that affect the fitness surface such as the generalism of predators.
We extend the results to competition, and argue that phenotypic plasticity’s
effect on the fitness surface will destabilize coexistence at local
scales, but stabilize coexistence at regional scales. Our study emphasizes
the need to incorporate variable interaction strengths due to phenotypic
plasticity into invasion biology and ecological theory on competition
and coexistence in fragmented landscapes.
PEACOR, S.D., L. Schiesari, and E.E. Werner. Mechanisms
of nonlethal predator effect on cohort size variation: ecological and
evolutionary implications. Ecology 88(6):1536-1547 (2007).
http://www.glerl.noaa.gov/pubs/fulltext/2007/20070016.pdf
Understanding the factors responsible for generating size variation
in cohorts of organisms is important for predicting their population
and evolutionary dynamics. We group these factors into two broad classes:
those due to scaling relationships between growth and size (size-dependent
factors), and those due to individual trait differences other than size
(size-independent factors; e.g., morphology, behavior, etc.). We develop
a framework predicting that the nonlethal presence of predators can
have a strong effect on size variation, the magnitude and sign of which
depend on the relative influence of both factors. We present experimental
results showing that size-independent factors can strongly contribute
to size variation in anuran larvae, and that the presence of a larval
dragonfly predator reduced expression of these size-independent factors.
Further, a review of a number of experiments shows that the effect of
this predator on relative size variation of a cohort ranged from negative
at low growth rates to positive at high growth rates. At high growth
rates, effects of size-dependent factors predominate, and predator presence
causes an increase in the scaling of growth rate with size (larger individuals
respond less strongly to predator presence than small individuals).
Thus predator presence led to an increase in size variation. In contrast,
at low growth rates, size-independent factors were relatively more important,
and predator presence reduced expression of these size-independent factors.
Consequently, predator presence led to a decrease in size variation.
Our results therefore indicate a further mechanism whereby nonlethal
predator effects can be manifest on prey species performance. These
results have strong implications for both ecological and evolutionary
processes. Theoretical studies indicate that changes in cohort size
variation can have profound effects on population dynamics and stability,
and therefore the mere presence of a predator could have important ecological
consequences. Further, changes in cohort size variation can have important
evolutionary implications through changes in trait heritability.
POTHOVEN, S.A., I. A. Grigorovich, G.L. FAHNENSTIEL, and M.D.
Balcer. Introduction of the Ponto-Caspian bloody-red mysis
Hemimysis anomala into the Lake Michigan basin. Journal
of Great Lakes Research 33:285-292 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070007.pdf
Hemimysis anomala G.O. Sars, 1907, a mysid species native to the Ponto-Caspian
region, was discovered during fall 2006 in the Lake Michigan basin.
Large numbers of individuals formed aggregations (averaging 1,540 ±
333 individuals/m2) in a shallow docking basin connected to the channel
linking Lake Michigan and Muskegon Lake. The population included females
(63%), males (35%), and juveniles (2%). The global invasion pattern
in H. anomala is similar to that in another Ponto-Caspian peracarid
crustacean, Echinogammarus ischnus. As with E. ischnus, the
expansion of H. anomala in North America is anticipated.
POTHOVEN, S.A., H.A. VANDERPLEOG, J.F. CAVALETTO, D.M. KRUEGER,
D.M. MASON, and S.B. BRANDT. Alewife planktivory controls the
abundance of two invasive predatory cladocerans in Lake Michigan. Freshwater
Biology 52(doi:10.1111/j.1365-2427.2007.01728.x):561-573 (2007).
1. We sampled along a nearshore transect (10-m bathymetric contour)
in Lake Michigan to determine diet, 24-h feeding periodicity, daily
ration and food requirements of an invasive fish, the alewife, Alosa
pseudoharengus, relative to zooplankton abundance and production.
Our objective was to determine whether the alewife controls the abundance
of two invasive, predatory cladocerans, Bythotrephes longimanus
and Cercopagis pengoi.
2. Bosminidae was the most abundant prey taxon and Chydoridae, Leptodora,
Chironomidae and Bythotrephes were the least abundant. Neither
Bythotrephes nor Cercopagis were important prey for
small alewives (≤100 mm). Bythotrephes was eaten by over
50% of large alewives (>100 mm) and accounted for 10–27% of
the diet weight. Cercopagis was eaten by about 30% of the large
alewives but only accounted 1% of the diet weight.
3. Food weight in stomachs was highest early in the night for small
alewives and lowest at night for large alewives. Chironomidae and large
Chydoridae were the preferred prey of small alewives. Bythotrephes
and large Chydoridae were the preferred prey for large alewives.
4. Food requirements of alewife were much less than production for most
prey taxa, although the consumption of Bythotrephes greatly
exceeded production on both dates. Alewives consumed only 3% of Cercopagis
production. High selectivity and food requirements of alewife for Bythotrephes,
and low selectivity and food requirements for Cercopagis, probably
explain the difference in abundance between these two invasive cladocerans
at our nearshore site in Lake Michigan.
RAIKOW, D. F., P. F. LANDRUM, and D. F. REID. Aquatic
invertebrate resting egg sensitivity to glutaraldehyde and sodium hypochlorite.
Environmental Toxicology and Chemistry 26(8):1770-773 (2007).
Ballast tank treatment technologies are currently in development to
reduce the risk of acquiring or transporting viable aquatic organisms
that could be introduced to ecosystems and become invasive. Aquatic
invertebrate resting eggs represent a challenge to such technologies
because of morphological and biochemical adaptations to stress that
also protect eggs from artificial stressors. To evaluate the potential
efficacy of chemical biocides for ballast tank treatment, the present
study examined the acute toxicity of glutaraldehyde and sodium hypochlorite
on resting eggs of the freshwater cladoceran Daphnia mendotae
and marine brine shrimp (Artemia sp.). Glutaraldehyde was toxic
to resting eggs of Artemia sp., as indicated by a lethal concentration
to 90% of organisms (LC90) of 95% confidence interval (226 ±
10 mg/L). Daphnia mendotae, in contrast, displayed erratic
responses to glutaraldehyde. Sodium hypochlorite was similarly toxic
to resting eggs of Artemia sp. and D. mendotae, which
displayed LC90s of 86.5 ± 3.0 and 78.3 ± 1.6 mg/L, respectively.
Burial in sediment protected resting eggs from toxicants. The present
results corroborate those from previous investigations of resting egg
sensitivity to artificial stressors, supporting the conclusions that
resting eggs are less sensitive than other life stages to artificial
stressors and that chemical biocide concentrations effective against
other life stages may be ineffective against resting stages.
RAIKOW, D. F., D. F. REID, E. R. Blatchley, G. JACOBS, and
P. F. LANDRUM. Effects of proposed physical ballast tank treatments
on aquatic invertebrate resting eggs. Environmental Toxicology and
Chemistry 26(4):717-725 (2007).
Adaptations in aquatic invertebrate resting eggs that confer protection
from natural catastrophic events also could confer protection from treatments
applied to ballast water for biological invasion vector management.
To evaluate the potential efficacy of physical ballast water treatment
methods, the present study examined the acute toxicity of heat (flash
and holding methods), ultraviolet (UV) radiation (254 nm), and deoxygenation
(acute and chronic) on resting eggs of the freshwater cladoceran Daphnia
mendotae and the marine brine shrimp Artemia sp. Both
D. mendotae and Artemia sp. were similarly sensitive
to flash exposures of heat (100% mortality at 70oC), but D. mendotae
were much more sensitive to prolonged exposures. Exposure to 4,000 mJ/cm2
of UV radiation resulted in mortality rates of 59% in Artemia sp.
and 91% in D. mendotae. Deoxygenation to an oxygen concentration
of 1 mg/L was maximally toxic to both species. Deoxygenation suppressed
hatching of D. mendotae resting eggs at oxygen concentrations
of less than 5.5 mg/L and of Artemia sp. resting eggs at concentrations
of less than 1 mg/L. Results suggest that UV radiation and deoxygenation
are not viable treatment methods with respect to invertebrate resting
eggs because of the impracticality of producing sufficient UV doses
and the suppression of hatching at low oxygen concentrations. Results
also suggest that the treatment temperatures required to kill resting
eggs are much higher than those reported to be effective against other
invertebrate life stages and species. The results, however, do not preclude
the effectiveness of these treatments against other organisms or life
stages. Nevertheless, if ballast tank treatment systems employing the
tested methods are intended to include mitigation of viable resting
eggs, then physical removal of large resting eggs and ephippia via filtration
would be a necessary initial step.
Rao, Y.R., and N. HAWLEY. Interbasin exchange flows
in Lake Erie. Proceedings, Sixth International Symposium on Stratified
Flows, Perth, Australia, December 11-14, 2006. International Association
of Hydraulic Engineering and Research, 245-250 pp. (2006). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060042.pdf
Exchange processes between the three basins of Lake Erie relevant
to water quality during summer stratified season are discussed in this
paper. Currents, water temperature, winds, radiation, and waves were
recorded at fixed moorings in Lake Erie during 2004 and 2005. Circulation
within and between the basins is studied. The thermal structure and
exchange processes during summer stratification and early fall indicates
that both barotropic and baroclinic processes influence the exchange
flows.
Rao, Y.R., and D.J. SCHWAB. Transport and mixing between
the coastal and offshore waters in the Great Lakes: A review. Journal
of Great Lakes Research 33:202-218 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070034.pdf
The Laurentian Great Lakes of North America have horizontal scales
of hundreds of kilometers and depth scales of hundreds of meters. In
terms of coastal dynamics, they behave much like inland seas and exhibit
physical processes characteristic of the coastal oceans. The lakes are
dynamically similar to the coastal ocean in that their horizontal dimensions
are larger than the vertical dimensions, and the principal source of
mechanical energy is the wind. The major difference in dynamical processes
is that the lakes are enclosed basins and are not connected to the deep
ocean. This paper presents an overview of some of the significant aspects
of physical processes in the coastal zones of the Great Lakes. The review
is based on examples ranging from lake-wide experiments like the International
Field Year on the Great Lakes (IFYGL) to several process-oriented coastal
boundary layer experiments. The basic circulations in the nearshore
zone and coastal boundary layer are summarized. The review concludes
with suggestions for future work on the understanding of the physical
processes that would have a bearing on lake management in the coastal
zones of the Great Lakes.
REID, D.F. Conversion of specific gravity to salinity
for ballast water regulatory management. NOAA Technical Memorandum GLERL-139.
NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 24
pp. (2006). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-139/tm-139.pdf
To reduce the risk of new aquatic species introductions to coastal
ecosystem via the ballast tanks of ocean-going ships, both the United
States and Canada have established regulatory and/or policy requirements
based on assuring that the salinity of incoming ballast water, including
residual ballast water, is 30 ppt or greater. However, common shipboard
practice for management of ballast water is to determine the specific
gravity of the water, not the salinity. Thus there is a technical disconnect
between the information the ship typically records and what the regulatory
agencies need. In 1981 a new equation of state for seawater was established,
including a highly accurate mathematical relationship between density,
salinity, temperature, and pressure. The equation is valid for salinity
from 2 to 42 (practical salinity) and temperature from -2 to 35oC. The
equation of state for seawater was used to calculate a set of tables
relating salinity to density and specific gravity, which were then converted
into a related series of graphs, presented in this report, that can
be used by ship’s crews and regulators alike to convert between
salinity and specific gravity.
REID, D.F., R. STURTEVANT, and S.A. POTHOVEN. Calling
on the public: Where in the Great Lakes basin is the newest aquatic
invader, Hemimysis anomala? Aquatic Invaders 18(1):1-7
(2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070006.pdf
A new aquatic invader, the bloody-red mysid shrimp (Figure 1), was
discovered in the Great Lakes in 2006, but has been confirmed only at
two locations (Figure 2). Scientists believe it probably has a wider
distribution, but has not been previously reported either because people
didn’t recognize it as a new organism, or simply didn’t
see it. Hemimysis anomala is difficult to locate because it
is nocturnal, preferring to hide in rocky cracks and crevices near the
bottom along the shoreline during daylight. However, it also sometimes
exhibits a unique swarming behavior, forming small dense reddish-tinged
clouds containing thousands of individuals concentrated in one location,
usually visible just below the water surface in a shadow zone (Figure
3). This is the basis for a new survey and monitoring program being
established which is asking for public assistance in locating other
occurrences of this organism.
RUBERG, S.A., S.B. BRANDT, R.W. MUZZI, N. HAWLEY, T. Bridgeman,
G.A. LESHKEVICH, J.C. LANE, and T.C. MILLER. A wireless real-time
coastal observation network. EOS Transactions 88(28):285-286
(2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070022.pdf
A new integrated coastal observation system is providing preliminary
data from the North American Great Lakes. This system can be implemented
in other coastal regions. To date, it has been successfully deployed
on Lakes Michigan, Huron, and Erie to make seabed to sea-surface measurements
of chemical, biological, and physical parameters, which are transmitted
wirelessly through buoys and permanent stations. Called the Real-Time
Coastal Observation Network (ReCON), the new system leverages existing
networking technology to provide universal access to a wide variety
of instrumentation through the use of an underwater Ethernet port server
[Austin, 2002]. A team of NOAA engineers and scientists has completed
the development and testing of this integrated coastal observation network.
RUBERG, S.A., D.F. Coleman, T.H. JOHENGEN, G.A. Meadows, H.W.
VanSumeren, G. A. LANG, and B. A. Biddanda. Groundwater plume
mapping in a submerged sinkhole in Lake Huron. Marine Technology
Society Journal 39(2):65-69 (2005). http://www.glerl.noaa.gov/pubs/fulltext/2005/20050038.pdf
A multidisciplinary exploratory project team from the Institute for
Exploration, the Great Lakes Environmental Research Laboratory, Grand
Valley State University, and the University of Michigan located and
explored a submerged sinkhole in Lake Huron during September 2003. A
CTD system and an ultra-short baseline (USBL) acoustic navigational
tracking system integrated with an open frame remotely operated vehicle
(ROV) provided high-resolution depth, temperature, and conductivity
maps of the sinkhole and plume. Samples were also peristaltically pumped
to the surface from a depth of 92 meters within and outside of the sinkhole
plume. A 1-2 m thick cloudy layer with a strong hydrogen sulfide odor
characterized the water mass close to the plume. Relative to ambient
lake water, water samples collected within this layer were characterized
by slightly higher (4-7.5 oC) temperatures, very high levels of chloride
and conductivity (10-fold) as well as extremely high concentrations
of organic matter (up to 400 mg C/L), sulfate, and phosphorus. Our observations
demonstrated the occurrence of unique biogeochemical conditions at this
submerged sinkhole environment.
Ruiz, G.M., and D.F. REID. Current state of understanding
about the effectiveness of Ballast Water Exchange (BWE) in reducing
Aquatic Nonindigenous Species (ANS) introductions to the Great Lakes
basin and Chesapeake Bay, USA: Synthesis and analysis of existing information.
NOAA Technical Memorandum GLERL-142. NOAA Great Lakes Environmental
Research Laboratory, Ann Arbor, MI, 127 pp. (2007). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-142/tm-142.pdf
This report summarizes the current state of knowledge about ballast
water exchange (BWE) as a management strategy by ships to reduce the
risk of invasions, with emphasis on two major U.S. ecosystems, the Great
Lakes and Chesapeake Bay. Today, most global trade occurs by shipping
among ports, creating unintended opportunities for transfer of aquatic
species that result in biological invasions. Ships transfer organisms
in their ballast tanks and on their hulls. To reduce the risk of invasions
from ballast water discharge, estimated annually to exceed 70,000,000
metric tons in the U.S., ships arriving from foreign ports are required
to conduct ballast water exchange (BWE) or alternative treatment before
discharging ballast. This management strategy became mandatory in the
United States for the Great Lakes and upper Hudson River in 1993, and
it has been required for ships arriving to the Chesapeake Bay and all
other ports since September 2004.
Schuler, L.J., P.F. LANDRUM, and M.J. Lydy. Response
spectrum for fluoranthene and pentachlorobenzene for the fathead minnow
(Pimephales promelas). Environmental Toxicology and Chemistry
26(1):139-148 (2007).
Internal body residue has been recognized as a potential dose metric
for toxicological assessments. This relationship between body residue
and biological effects, including both lethal and sublethal effects,
is critically important for determining environmental quality in risk
assessments. The present study identified the toxic equivalent body
residues for fluoranthene (FLU) and pentachlorobenzene (PCBz) associated
with mortality, reduced growth, and decreased hatchability in the fathead
minnow. The toxic equivalent body residue was defined as the total of
the parent compound and the organically extractable metabolites for
FLU and of the parent compound only for PCBz, because no biotransformation
was measurable. The lethal body residues corresponding to 50% mortality
were 0.80 and 1.26 umol/g wet weight for FLU and PCBz, respectively.
As expected, residues associated with sublethal effects generally are
2- to 40-fold lower than the lethal residues for FLU and PCBz. Juvenile
fish growth was the most sensitive endpoint examined for both compounds.
The maximum allowable toxicant residues were 0.02 and 0.43 umol/g wet
weight for FLU and PCBz, respectively. The information collected from
the present study will permit a greater understanding of residue–response
relationships, which will be useful in risk assessments.
Schuler, L.J., P.F. LANDRUM, and M.J. Lydy. Response
spectrum of pentachlorobenzene and fluoranthene for Chironomus tentans
and Hyalella azteca. Environmental Toxicology and Chemistry
26(6):1248-1257 (2007).
The whole-body residues of pentachlorobenzene (PCBz) and fluoranthene
(FLU) in Hyalella azteca and Chironomus tentans were
determined for a variety of chronic sublethal effects. The endpoints
evaluated for H. azteca included 28-d growth and survival and
42-d growth, survival, and reproduction. Adverse effects to C. tentans
also were determined at multiple endpoints including 10-d growth, cumulative
pupation and emergence, and reproduction. The lowest-observed-effect
residue (LOER) based on whole-body residues associated with growth was
consistent between compounds and species tested with concentrations
ranging from 0.17 to 0.33 umol/g. For H. azteca, the most sensitive
endpoints were growth at 0.23 umol/g and reproduction at 0.11 umol/g
for PCBz and FLU, respectively. For C. tentans, the most sensitive
endpoints were emergence, development and reproduction at 0.02 umol/g,
and development and reproduction at 0.15 umol/g for PCBz and FLU, respectively.
Compared to residues associated with acute lethality, the most sensitive
sublethal endpoints were approximately 4 and 60 times lower for PCBz
and FLU, respectively. The relative consistency of the sublethal endpoints
suggests that body residues can be a valuable tool to evaluate bioaccumulation
data as part of a risk assessment to predict adverse effects to biota.
STOW, C.A., C.R. Allen, and A.S. Garmestani. Evaluating
Discontinuities in Complex Systems: Toward Quantitative Measures of
Resilience. Ecology and Society 12(1):26 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070036.pdf
The textural discontinuity hypothesis (TDH) is based on the observation
that animal body mass distributions exhibit discontinuities that may
reflect the texture of the landscape available for exploitation. This
idea has been extended to other complex systems, hinting that the identification
and quantification of discontinuities in the distributions of appropriate
variables may provide clues to emergent system properties such as resilience.
We propose a discontinuity index, based on the vector norm of the full
assemblage of observed discontinuities, as a means to quantify and compare
this characteristic among systems. We also evaluate four methods to
identify the number and location of the most prominent discontinuities.
Although results of the four methods are similar, they are not identical,
and we conclude that this problem is best addressed with a consistent
operationally defined approach in an adaptive inference framework.
STOW, C.A., M.E. Borsuk, and K.H. Reckhow. Chapter
5 - Ecosystem Risk Assessment: The Neuse River Estuary, North Carolina.
In Risk Assessment for Environmental Health. M. Robson and
W. Toscano (Eds.). John Wiley and Sons, San Francisco, CA, 563-585 (2007).
Students who complete this chapter will be able to: (1) Appreciate
the role of models in ecological risk assessment, (2) Recognize the
high intrinsic uncertainties in making ecological forecasts, (3) Understand
the distinction between science and policy in environmental decision
making, and (4) Become familiar with the concept of "adaptive management".
Ecosystem risk assessment involves evaluating the current state of an
ecosystem, deciding what state the system should be in, and forecasting
its future state under alternative management options so that decision
makers can choose the management actions that are most likely to attain
the desired ecosystem state.
VANDERPLEOG, H.A., T.H. JOHENGEN, P.J. Lavrentyev, C. Chen,
G.A. LANG, M.A. Agy, M.H. Bundy, J.F. CAVALETTO, B.J. EADIE, J.R. LIEBIG,
G.S. MILLER, S.A. RUBERG, and M.J. McCORMICK. Anatomy of the
recurrent coastal sediment plume in Lake Michigan and its impacts on
light climate, nutrients, and plankton. Journal of Geophysical Research
112(C03S90, doi:10.1029/2004JC002379):23 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070010.pdf
As part of the Episodic Events Great Lakes Experiment, we sampled
total suspended matter (TSM), light climate, nutrients, and plankton
along cross-margin transects in southern Lake Michigan during February,
March, and April 1998–2000 to capture conditions before, during,
and after the occurrence of storm-driven recurrent coastal sediment
plumes to define the anatomy of the resuspension events and get insights
into their interactions with nutrients and plankton. Variability in
timing and strength of winter storms among years led to different timing,
intensity, and extent of plumes among years. TSM concentrations in the
core of plumes varied between 15 and 30 mg L-1, and photic depth was
reduced to ~1 to 2 m, thus potentially seriously limiting phytoplankton
growth in plume areas. Total P concentration was highly correlated with
TSM and river influence. Chlorophyll concentrations were lower in plume
regions than in adjacent areas, in contrast to the relatively constant
chlorophyll concentration across the plume predicted by a coupled hydrodynamic
and nutrient-phytoplankton-zooplankton model. Contrary to expectation,
protozoan microzooplankton (MZ) biomass was not more abundant in the
plume than adjacent waters, but was highest in nearshore areas receiving
river inflow. Storms affected horizontal distribution of zooplankton.
Because of the lower concentrations of phytoplankton in the plume, the
plume over the short term had a negative impact on zooplankton during
this food-limiting season. Our results combined with those of other
EEGLE studies lead us to conclude that storms and storm-driven plumes
had a negative effect on the planktonic food web.
Yang, X.-Y., D. Wang, J. WANG, and R.X. Huang. Connection
between the decadal variability in the southern ocean circulation and
the southern annual mode. Geophysical Research Letters 34(L16604,
doi:10.1029/2007GL030526):5 pp. (2007). http://www.glerl.noaa.gov/pubs/fulltext/2007/20070026.pdf
Previous studies demonstrated the remarkable upward trend of the Southern
Annular Mode (SAM) and Southern Ocean wind stress in association with
anthropogenic forcing. An oceanic reanalysis data set is used to investigate
the response of the circulation in the Southern Ocean to the decadal
variability of SAM. Our results indicate the strengthening and the poleward
shift of the northward Ekman velocity as well as the Ekman pumping rate,
which led to a corresponding strengthening trend in the Deacon Cell.
This strengthening, in turn, intensified the meridional density gradient
and the tilting of the isopycnal surfaces. On the interannual time scale,
the Antarctic Circumpolar Currents (ACC) transport exhibits a positive
correlation with SAM index as seen separately in observations. However,
there is no significant trend in the total transport of ACC. Possible
reasons are discussed.
You, J., P.F. LANDRUM, T.A. Trimble, and M.J. Lydy.
Availability of polychlorinated biphenyls in field-contaminated sediment.
Environmental Toxicology and Chemistry 26(9):1940-1948 (2007).
Two chemical approaches, Tenax extraction and matrix solid phase microextraction
(matrix-SPME), were evaluated as surrogates to estimate bioavailability
of polychlorinated biphenyls (PCBs) from field-contaminated sediment.
Aroclor 1254 was the primary contaminant found in sediment from Crab
Orchard Lake in Marion, Illinois, USA, and a total of 18 PCB congeners
were selected for study. Bioaccumulation was determined by exposing
the freshwater oligochaete, Lumbriculus variegatus, to the
sediment for 28 d. Differences in the rapidly desorbing fraction of
PCBs and fraction desorbed within 6 h, defined by Tenax extraction,
accounted for 39 and 31% of the differences among biota-sediment accumulation
factor values, respectively. A better relationship (r2= 0.95) was found
between the oligochaete PCB body residues and the concentration of PCBs
in the rapidly desorbing fraction of sediment. The degree of chlorination
and planarity of the PCB congeners affected both desorption and bioaccumulation.
The higher chlorine substituted and planar PCBs showed less chemical
and biological availability, due to their stronger sorption to sediment,
compared to the lower chlorinated and nonplanar PCBs. Accumulation of
PCBs by L. variegatus correlated well (r2=0.88) with matrix-SPME
fiber concentrations. The ratio of measured body residue to estimated
body residue from the pore water concentration measured by matrix-SPME
ranged from 0.4 to 1.3 with an average of 0.9. Overall, both Tenax and
matrix-SPME approaches were useful surrogates of bioaccumulation for
a field-contaminated sediment.
Zaiko, A., S. Olenin, D. Daunys, and T.F. NALEPA.
Vulnerability of benthic habitats to the aquatic invasive species. Biological
Invasions 9:(doi 10.1007/s10530-006-9070-0):703-714 (2007). http://www.glerl.noaa.gov/pubs/fulltext/2006/20060037.pdf
A comparative vulnerability analysis of 16 selected benthic habitat
types in the SE Baltic Sea waters and the Curonian lagoon, including
Klaipeda strait, was performed using long-term monitoring datasets (1980–2003)
and results of several other surveys in the lagoon and the sea. Results
indicated that invasive species richness (number of alien species per
habitat) in lagoon habitats was significantly higher than in the sea.
Habitats formed by artificial rock and stone, sand, mud, and habitats
modified by zebra mussel shell deposits appeared to be the most invaded.
Highest invasive species richness occurred in habitats with high native
species richness indicating that the main factors driving native species
distribution (such as favourable physical conditions, habitat alterations
generated by human or/and biotic activities) are also driving aquatic
invaders. Physical factors distinguished to be the most important for
native and invasive species distribution were salinity, depth range
(expressed by the maximal and minimal depths difference within a habitat),
shallowness of a habitat (expressed by a minimal depth), and availability
of a hard substrate.
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