GLERL Publications Abstracts: FY 1995

Publications List Key
Capitalized names represent GLERL authors.
* = Not available from GLERL.
** = Available in GLERL Library only.

ASSEL, R.A. Great Lakes Ice Cover Studies. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 4 pp. (1995).

No abstract.

ASSEL, R.A. Long term trends in Laurentian Great Lakes ice cover. GLERL Open File Report, Great Lakes Environmental Research Laboratory, Ann Arbor, MI 5 pp. (1994). https://www.glerl.noaa.gov/pubs/fulltext/1994/19940007.pdf

No abstract.

ASSEL, R.A., T.E. CROLEY, and K. Schneider. Computer visualization of long-term average Great Lakes temperature and ice cover. Journal of Great Lakes Research 20(4):771-782 (1994). https://www.glerl.noaa.gov/pubs/fulltext/1994/19940004.pdf

The Great Lakes Environmental Research Laboratory (GLERL) developed data sets of daily long-term averages over the annual cycle for surface water temperature, ice cover concentration, and derived lake-averaged vertical temperature profiles for each of the Laurentian Great Lakes. The two-dimensional data sets have a spatial resolution of approximately 2.5 km and are geo-referenced with latitude and longitude. A lake bathymetry data set was also produced for the same grid. The objective of assembling these particular data sets was to develop a computer tool to visualize and explore spatial and particularly temporal relationships between long-term averages of temperature (surface and lake-averaged vertical profile), ice cover, and bathymetry on a given lake and between lakes. Here, we briefly describe the data sets, summarize data sources and algorithms used to develop these data sets, and discuss the limitations of these data. We also briefly summarize the capabilities of the interactive menu-driven system to manipulate the display and daily long-term average temperatures and ice cover.

ASSEL, R.A., and D.M. Robertson. Changes in winter air temperatures near Lake Michigan, 1851-1993, as determined from regional lake-ice records. Limnology and Oceanography 40(1):165-176 (1995). https://www.glerl.noaa.gov/pubs/fulltext/1995/19950019.pdf

Records of freezeup and breakup dates for Grand Traverse Bay, Michigan, and Lake Mendota, Wisconsin, are among the longest ice records available near the Great Lakes, beginning in 1851 and 1855, respectively. The timing of freezeup and breakup results from an integration of meteorological conditions (primarily air temperature) that occur before these events. Changes in the average timing of these ice-events are translated into changes in air temperature by the use of empirical and process-driven models. The timing of freezeup and breakup at the two locations represents an integration of air temperatures over slightly different seasons (months). Records from both locations indicate that the early winter period before about 1890 was ~1.5°C cooler than the early winter period after that time; the mean temperature has, however, remained relatively constant since about 1890. Changes in breakup dates demonstrate a similar 1.0-1.5°C increase in late winter and early spring air temperatures about 1890. More recent average breakup dates at both locations have been earlier than during 1890-1940, indicating an additional warming of 1.2°C in March since about 1940 and a warming of 1.1 °C in January-March since about 1980. Ice records at these sites will continue to provide an early indication of the anticipated climatic warming, not only because of the large response of ice cover to small changes in air temperature but also because these records integrate climatic conditions during the seasons (winter-spring) when most warming is forecast to occur. Future reductions in ice cover may strongly affect the winter ecology of the Great Lakes by reducing the stable environment required by various levels of the food chain.

ASSEL, R.A., C.E. SELLINGER, D.E. MEYER, and R.N. KELLEY. Great Lakes states monthly precipitation data - beginning of record to 1990. NOAA Technical Memorandum ERL GLERL-86, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (PB96-125604-XAB) 39 pp. (1995). https://www.glerl.noaa.gov/pubs/tech_reports/glerl-086/tm-086.pdf

Monthly precipitation data for 2,015 stations from beginning of record to 1947 for the eight Great Lakes states were digitized using an electronic scanner and optical character recognition software. These data were combined with digital monthly station precipitation data from 1948 to 1990 that was obtained from the National Climate Data Center (NDC) in Asheville, North Carolina. The total number of stations in the combined data set is 3,447. Station latitude, longitude, elevation, and station name and changes in these metadata was also digitized. A complete list of stations is given as an appendix to the report. Data reduction, verification, quality control, and analysis methods are summarized. The spatial and temporal distribution patterns of the number of stations is presented. The digital data has been archived and is available from NCDC in Asheville.

Atwood, D.K., A.W. BRATKOVICH, M. Gallagher, and G.L. Hitchcock. Introduction to the dedicated issue. Estuaries 17(4):729-731 (1994).

No abstract.

Bedford, K.W., and D. SCHWAB. Report of the First Annual Great Lakes Forecasting System (GLFS) Users' Workshop. Great Lakes Forecasting System (GLFS) Users' Workshop, Sandusky, OH, September 22, 1994. Ohio Sea Grant College Program, Columbus, OH, 16 pp. (1995).

No abstract.

Bedford, K.W., and D.J. SCHWAB. The Great Lakes Forecasting System: An overview. Proceedings, 1994 Hydraulic Engineering Conference, C.V. Cotroneo and R.R. Rumer (eds.), Buffalo, NY, August 1-5, 1994. American Society of Civil Engineers, New York, NY, 197-201 (1994).

The Great Lakes Forecasting System is a full three-dimensional model-based system designed to make regularly scheduled predictions of the physical status of each of the Great Lakes. Due to its shallowness and rapid response to storms, Lake Erie has been selected as the prototype. Daily predictions are made for three-dimensional velocity and temperature distributions as well as water level and wind wave distributions. The system is designed to function with existing, operationally collected data including AVHRR and GOES satellite data. Products are distributed through two systems, the NOAA-based COASTWATCH Program and the PC-based GLFSview system. Research concerns include identification of procedures for coupled predictions with atmospheric models, developing satellite procedures for including the effect of clouds on heat flux estimates, and determining the adequacy of wave model predictions for shallow water effects. Funding for this project comes from a suite of thirteen sources, ranging from federal to local governments and private companies and foundations.

BEETON, A.M. Lakes and Ponds. In Encyclopedia of the Environment, R.A. Eblen and W.R. Eblen (eds.). Houghton Mifflin Company, Boston, MA, 394-395 (1994).

No abstract.

BRATKOVICH, A.W., S.P. Dinnel, and D. Goolsby. Variability and prediction of freshwater and nitrate fluxes for the Louisiana-Texas Shelf: Mississippi and Atchafalaya River source functions. Estuaries 17(4):766-778 (1994).

Time histories of riverine water discharge, nitrate concentration, and nitrate flux have been analyzed for the Mississippi and Atchafalaya rivers. Results indicate that water discharge variability is dominated by the annual cycle and shorter-time-scale episodic events presumably associated with snowmelt runoff and spring or summer rains. Interannual variability in water discharge is relatively small compared to the above. In contrast, nitrate concentration exhibits strongest variability at decadal time scales. The interannual variability is not monotonic but more complicated in structure. Weak covariability between water discharge and nitrate concentration leads to a relatively "noisy" nitrate flux signal. Nitrate flux variations exhibit a low-amplitude, long-term modulation of a dominant annual cycle. Predictor-hindcastor anayses indicate that skilled forecasts of nitrate concentration and nitrate flux fields are feasible. Water discharge was the most reliably hindcast (on seasonal to interannual time scales) due to the fundamental strength of the annual hydrologic cycle. However, the forecasting effort for this variable was less successful than the hindcasting effort, mostly due to a phase shift in the annual cycle during our relatively short test period (18 mo). Nitrate concentration was more skillfully predicted (seasonal to interannual time scales) due to the relative dominance of the decadal-scale portion of the signal. Nitrate flux was also skillfully forecast even though historical analyses seemed to indicate that it should be more difficult to predict than either water discharge or nitrate concentration.

Bruner, K.A., S.W. Fisher, and P.F. LANDRUM. The role of the zebra mussel, Dreissena polymorpha, in contaminant cycling: I. The effect of body size and lipid content on the bioconcentration of PCBs and PAHs. Journal of Great Lakes Research 20(4):725-734 (1994). https://www.glerl.noaa.gov/pubs/fulltext/1994/19940002.pdf

The zebra mussel, Dreissena polymorpha, a recent invader to the Great Lakes, may influence contaminant cycling by bioconcentrating high levels of hydrophobic contaminants in its tissue. To better understand zebra mussel bioconcentration and ultimately, contaminant cycling, we measured bioconcentration factors (BCFs) and kinetic parameters for accumulation of polychlorinated biphenyl and polycyclic aromatic hydrocarbon congeners for two size classes of mussels and for a pre-spawning (high lipid) and post-spawning (low lipid) mussel population. High lipid, pre-spawning mussels had greater BCFs and faster uptake kinetics for the highly hydrophobic compounds, i.e. hexachlorobiphenyl and benzo(a)pyrene, than the low lipid, post-spawning mussels, BCFs and uptake kinetics determined for the less hydrophobic compounds, i.e., tetrachlorobiphenyl and pyrene, were not measurably influenced by differences in lipid content. Small mussels (15 mm shell length) had higher BCFs and faster uptake kinetics for all compounds compared to larger (21 mm shell length) mussels. Contaminant elimination was not affected by size or differences in lipid levels. For both lipid levels and size classes of mussels, the BCFs were positively correlated with compound log octanol:water partition coefficient. Hence, the lipid affinity of a compound can be a good indicator of mussel contaminant accumulation. Potentially large contaminant concentration in zebra mussels may alter contaminant cycling in the Great Lakes by increasing contaminant transfer to mussel predators. Selective predation on small, pre-spawning (high lipid) mussels may present a greater hazard to predators than predation on larger, post-spawning (low lipid) mussels.

Bruner, K.A., S.W. Fisher, and P.F. LANDRUM. The role of the zebra mussel, Dreissena polymorpha, in contaminant cycling: II. Zebra mussel contaminant accumulation from algae and suspended particles, and transfer to the benthic invertebrate, Gammarus fasciatus. Journal of Great Lakes Research 20(4):735-750 (1994). https://www.glerl.noaa.gov/pubs/fulltext/1994/19940003.pdf

To determine the contribution of ingested material to zebra mussel contaminant accumulation, contaminant assimilation efficiencies (fraction of the total contaminant exposure that is accumulated into tissue, AE) from spiked algae and suspended sediment particles were measured for benzo(a)pyrene, the insecticide DDT, and selected polychlorinated biphenyl (PCB) congeners. Contaminant transfer from zebra mussel feces to the benthic invertebrate, Gammarus fasciatus, was determined by measuring AE from PCB contaminated mussel feces to gammarids. Further, mussel contaminant AE values coupled with physiological and environmental parameters were used in a steady-state model to examine the relative importance of the algal, suspended sediment, and water-borne exposure routes for a representative organochlorine compound, hexachlorobiphenyl (HCBP). The relative accumulation via the fecal and water exposure routes were modeled for gammarids. Mussel AE values for contaminant accumulation were greater from algae than from suspended sediments. Model estimates indicated that when contaminant concentrations in the water were near detection limits, dietary exposure was the primary route of contaminant accumulation (61.5% of the total contaminant concentration). Water was the most important route of contaminant exposure (89.5% of the total contaminant concentration) when contaminant concentrations in water were 10 times greater than the compound detection limit. Suspended sediment was the major dietary source of contaminants at all water concentrations. Percent AE for zebra mussel feces to gammarid transfer were high 79.0 and 89.4 % for hexachlorobiphenyl and tetrachlorobiphenyl respectively but not statistically different. Model estimates indicated that the dietary route of exposure was the primary source of PCB exposure for gammarids and indicated a potential for PCB biomagnification in the mussel-based detrital food chain. Results suggest that zebra mussels have the potential to change contaminant cycling in the Great Lakes by rerouting dissolved and particulate bound contaminants through zebra mussel food chains with possible biomagnification in upper trophic levels.

Crecelius, E., B. Lasora, L. Lefkovits, P.F. LANDRUM, and B. Barrick. Chapter 5: Chemical Analyses. In Assessment and Remediation of Contaminated Sediments (ARCS) Program: Assessment Guidance Document, Great Lakes National Program Office, Environmental Protection Agency, Chicago, IL, EPA 905-B94-002, 69-85 (1994).

No abstract.

CROLEY, T.E.II. GLERL Water Resources Research Program. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 4 pp. (1995).

No abstract.

CROLEY, T.E.II. Hydrological impacts of climate change on the Laurentian Great Lakes. In Trends in Hydrology, Research Trends, The Council of Scientific Research Integration, Trivandrum, India, 1-25 (1994).

The Great Lakes Environmental Research Laboratory (GLERL) used their conceptual models for simulating moisture storages in, and runoff from, the 121 watersheds draining into the Laurentian Great Lakes, over-lake precipitation into each lake, and the heat storages in, and evaporation from, each lake. GLERL combined these components as net water supplies for each lake to consider climate change scenarios, developed from general circulation models of the global atmosphere, through linkages on air temperature, precipitation, humidity, wind speed, and cloud cover. Steady-state doubling of atmospheric CO2 was considered by abstracting changes in linkages, making these changes in historical data, observing the impact of the changed data in the model outputs, and comparing it to model results using unchanged data, representing comparison to an unchanged atmosphere. This study indicates a 20 to 100% reduction in net basin supplies for each of the Great Lakes. The basins' various moisture storages become dryer and the lakes are warmer with associated hydrological impacts.

CROLEY, T.E.II. Laurentian Great Lakes dynamics, climate, and response to change. In The Role of Water and the Hydrological Cycle in Global Change, H.R. Oliver, and S. A. Oliver (eds.). Springer-Verlag, New York, 253-296 (1995).

No abstract.

CROLEY, T.E.II, D.H. LEE, and B.M. LOFGREN. GLERL Hydrological Modeling. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 4 pp. (1995).

No abstract.

CROLEY, T.E.II, D.H. LEE, B.M. LOFGREN, and F.H. QUINN. Great Lakes Water Resources Forecasting. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 4 pp. (1995).

No abstract.

CROLEY, T.E.II, and F.H. QUINN. Climate Transposition in the Great Lakes. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 4 pp. (1995).

No abstract.

CROLEY, T.E.II, F.H. QUINN, K. Kunkel, and S. Changnon. Potential Great Lakes hydrology and lake level impacts resulting from global warming. Sixth Symposium on Global Change Studies, Dallas, TX, January 15-20, 1995. American Meteorological Society, Boston, MA, 67-72 (1995).

No abstract.

Dinnel, S.P., T. Whitledge, A.W. BRATKOVICH, and B.H. Jones. Buoyancy and nutrient exchange in the Mississippi River outflow region. Proceedings, Nutrient Enhanced Coastal Ocean Productivity Synthesis Workshop, Baton Rouge, LA, April 26-27, 1994. Louisiana Sea Grant, Baton Rouge, LA, 28-33 (1995).

No abstract.

EADIE, B.J., R. Amon, R. Benner, J.F. CAVALETTO, J.B. Cotner, W.S. GARDNER, M.B. LANSING, and D. Pakulski. Organic matter decomposition, nitrogen recycling, and oxygen consumption in the Mississippi River plume/Gulf Shelf region. Proceedings, Nutrient Enhanced Coastal Ocean Productivity Synthesis Workshop, Baton Rouge, LA, April 26-27, 1994. Louisiana Sea Grant, Baton Rouge, LA, 40-45 (1995).

No abstract.

EADIE, B.J., B.A. McKee, M.B. LANSING, J.A. ROBBINS, S. Metz, and J.H. Trefry. Records of nutrient-enhanced coastal ocean productivity in sediments from the Louisiana continental shelf. Estuaries 17(4):754-765 (1994).

Shelf sediments from near the mouth of the Mississippi River were collected and analyzed to examine whether records of the consequences of anthropogenic nutrient loadings are preserved. Cores representing approximately 100 yr of accumulation have increasing concentrations of organic matter over this period, indicating increased accumulation of organic carbon, rapid early diagenesis, or a combination of these processes. Stable carbon isotopes and organic tracers show that virtually all of this increase is of marine origin. Evidence from two cores near the river mouth, one within the region of chronic seasonal hypoxia and one nearby but outside the hypoxic region, indicate that changes consistent with increased productivity began by approximately the mid-1950s when the inorganic carbon in benthic forams rapidly became isotopically lighter at both stations. Beginning in the mid-1960s, the accumulation of organic matter, organic d13C, and d15N all show large changes in a direction consistent with increased productivity. This last period coincides with a doubling of the load of nutrients from the Mississippi River, which levelled off in the mid-1980s. These data support the hypothesis that anthropogenic nutrient loading has had a significant impact on the Louisiana shelf.

FAHNENSTIEL, G.L., M.J. McCORMICK, G.A. LANG, D.G. Redalje, S.E. Lohrenz, M. MARKOWITZ, B. WAGONER, and H.J. CARRICK. Taxon-specific growth and loss rates for dominant phytoplankton populations from the northern Gulf of Mexico. Marine Ecology Progress Series 117:229-239 (1995).

Taxon-specific growth and sedimentation rates of dominant phytoplankton were measured during 2 cruises (summer 1990 and spring 1991) in the northern Gulf of Mexico as part of the NOAA Nutrient-Enhanced Coastal Ocean Productivity (NECOP) program. Microzooplankton grazing rates also were measured during the summer cruise. During each of the cruises, a series of stations from the Mississippi River mouth to the hypoxia region (located ca 50 to 100 km west) were sampled to examine variability of growth and loss processes along a strong environmental gradient. Significant taxa- and group-specific differences were noted for both growth and loss rates. Growth rates ranged from <0.1 to 3.0 d-1 with highest rates in the plume region during the summer cruise, where surface rates were close to or exceeded previous mmax values for several taxa. For all taxa, growth rates were lower in the hypoxia region (mean=0.5 d-1) than in the plume region (mean =1.1 d-1); soluble nitrogen concentrations explained over 50% of the variability in growth rates. Diatom growth rates were similar to non-diatoms in the plume region, but were significantly lower in the hypoxia region, which suggests that silica limitation may exist in this region. The fate of phytoplankton appeared to be controlled by size and by the degree of silicification. Significant microzooplankton grazing loss rates were noted only for small taxa (<20 mm). For microflagellates, microzooplankton grazing rates averaged 82% (range 42 to 214%) of the growth rate; sedimentation rates were always <1% of the growth rate. Sedimentation was an important loss for several diatoms, with significant taxon-specific and seasonal differences noted. Large colonial diatoms, such as Skeletonema costatum and Thalassiosira rotula, exhibited the highest sedimentation rates in the plume region during the spring cruise (0.2 to 1.0 d-1), whereas the lowest rates (<0.01 d-1) were noted for Rhizosolenia fragilissima and Ceratulina pelagica in the hypoxia region during the summer cruise. Our results suggest that in the northern Gulf of Mexico, phytoplankton rate processes proceed very rapidly, with growth rates primarily controlled by the supply of nitrogen via the Mississippi River and the fate controlled primarily by size and density (silicification).

Fox, R., P.F. LANDRUM, and L. McCrone. Chapter 1: Introduction. In Assessment and Remediation of Contaminated Sediments (ARCS) Program: Assessment Guidance Document, EPA, Great Lakes National Program Office, Chicago, IL, EPA 905-B94-002, 1-9 (1994).

No abstract.

GARDNER, W.S., R. Benner, G. Chin-Leo, J.B. COTNER, B.J. EADIE, J.F. CAVALETTO, and M.B. LANSING. Mineralization of organic material and bacterial dynamics in Mississippi River plume water. Estuaries 17(4):816-828 (1994).

Net remineralization rates of organic matter and bacterial growth rates were observed in dark-bottle incubation experiments conducted in July-August and February with water samples collected from sites in the Mississippi River plume of the Gulf of Mexico. Our objectives were to measure site-specific degradation rates of labile dissolved and particulate organic matter, quantify the potential importance of bacteria in these processes, and examine the kinetics of degradation over time. Unfiltered samples, and samples treated to remove (or dilute out) particles larger than bacteria, were enclosed in 9-L bottles and incubated in the dark for 3-5 d. Respiration rates and inorganic compound accumulation rates were higher in summer than in winter and were highest in unfiltered surface samples at sites of intermediate salinities where phytoplankton were most abundant. The ratio of ammonium accumulation to oxygen removal in summer experiments suggested that the mineralized organic material resembed "Redfield" stoichiometry. Chemical fluxes were greater in bottles containing large (>1-3 mm) particles than in the bottles with these particles removed, but bacterial activities were generally similar in both treatments. These results suggest that particle consumers were an important component of total organic matter degradation. However, these experiments may have underestimated natural bacterial degradation rates because the absence of light could affect the production of labile organic substrates by phytoplankton. In agreement, with this hypothesis, bacterial growth rates tended to decrease over time in summer in surface plume waters where phytoplankton were abundant. In conjunction with other data, our results indicate that heterotrophic processes in the water column are spatially and temperally dependent on phytoplankton production.

GARDNER, W.S., H.A. BOOTSMA, C. Evans, and P.A. St. John. Improved chromatographic analysis of 15N:14N ratios in ammonium or nitrate for isotope addition experiments. Marine Chemistry 48:271-282 (1995).

Estimating nitrogen transformation in aquatic ecosystems by isotope dilution techniques is simplified by directly measuring nitrogen isotopic ratios for NH4+ in the water using high performance cation exchange liquid chromatography (HPLC). Modifications of HPLC conditions and implementation of a median-area method for retention time determination improved and linearized a previously reported sigmoid relationship between the retention time shift (RTshift) of the NH4+ peak and the ratio of [15NH4+]:[Total NH4+] in seawater fortified with 15NH4+. Increasing the temperature of the HPLC column from 47 to 85oC increased mobile phase buffer flow rate relative to column back pressure, decreased the retention time for NH4+, and allowed the buffer pH to be optimized relative to the pK of NH4+. The use of median-area rather than maximum-height to define the retention time of NH4+ further improved the linearity (r>0.995) of the relationship between the ratio [15NH4+]:[Total NH4+] and RTshift over the range of isotope ratios. Reduction of NO3- to NH4+ by adding zinc dust to acidified (pH 2) seawater or lakewater samples, followed by pH neutralization, and subsequent analysis of NH4+ isotope ratios by HPLC, extended application of the method to isotope dilution experiments with NO3-. Advantages of this direct-injection method over mass-measurement approaches traditionally used for isotope dilution experiments include small sample size and minimal sample preparation.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. FY 1993 Yearly Report. C.M. Darnell and D.F. Reid, (eds ). Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 50 pp. (1994).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Publications by the staff of the Great Lakes Environmental Research Laboratory. C.M. Darnell (ed.). NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 94 pp. (1995).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. FY 1994 Yearly Report. C.M. Darnell and D.F. Reid (eds.). NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 49 pp. (1995).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. The Lake St. Clair Problem. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 2 pp. (1995).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Nearshore Hydrodynamics 1995 Update. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 3 pp. (1995).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Environmental Stewardship and Natural Resource Management Contributions by NOAA's Great Lakes Environmental Research Laboratory A Synopsis. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 2 pp. (1995).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. NOAA's Great Lakes Environmental Research Laboratory, Information Sheet. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 2 pp. (1995).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Cargo Sweeping on the Great Lakes: Balancing Environmental Protection, Safety, and Economics. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 2 pp. (1995).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. The Great Lakes Coastal Forecasting System A Coastal Prediction Tool. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 2 pp. (1995).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. The Saginaw Bay National Watershed Initiative: Participation and Contributions of NOAA's Great Lakes Environmental Research Laboratory. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 2 pp. (1995).

No abstract.

HARKEY, G.A., P.L. VAN HOOF, and P.F. LANDRUM. Bioavailability of polycyclic aromatic hydrocarbons from a historically contaminated sediment core. Environmental Toxicology and Chemistry 14(9):1551-1560 (1995).

To determine changes in bioavailability of selected polycyclic aromatic hydrocarbons (PAHs) with sedient aging, Lumbriculus variegatus were exposed for 4 weeks to sediment core sections taken from a contaminated lake. Core depths included surficial (0 to 4 cm), 4- to 8-, 12- to 16-, 28- to 32-, and 44- to 48-cm sections deposited from approximately 1899 to 1993, and were known to be historically contaminated with PAHs. Bioaccumulation was maximal at the 12- to 16-cm depth (circa 1967) where sediment PAH concentrations were greatest. Accumulation was generally below detection limits in the 0- to 4-cm depths, even though sediment concentration of some compounds were comparable to those at the 12- to 16-cm depth where accumulation was great enough to generate accurate kinetics curves. Accumulation peaked at about 96 h, then declined over the remainder of the study for the lower-molecular-weight PAHs. For most higher-molecular-weight PAHs, accumulation peaked at about 2 weeks, then declined only slightly after 4 weeks. The differential bioavailability observed between surficial and at-depth core sections raises questions concerning the adequacy of results generated from toxicity and bioaccumulation tests routinely conducted with surficial sediments.

HAWLEY, N., and B.M. Lesht. Does local resuspension maintain the benthic nepheloid layer in southeastern Lake Michigan? Journal of Sedimentary Research A65(1):69-76 (1995).

Time-series observations of water temperature, water transparency, and current velocity at four stations in southeastern Lake Michigan show that the benthic nepheloid layer is probably not maintained by the local resuspension of bottom sediment. Local resuspension may occasionally occur in the deep parts of the lake, but it seems likely that vertical mixing and offshore advection of sediment-laden water maintain the benthic nepheloid layer during most of the year. Although sediment trap data have been interpreted as indicating that local resuspension does occur, it is more likely that the increased sediment fluxes observed near the bottom are due to vertical redistribution of material already in suspension.

Holcombe, T.L., D.F. REID, and D.L. Davins. New bathymetry of the Great Lakes being compiled as part of NOAA's Great Lakes data rescue effort. Earth System Monitor :10-11 (1995).

No abstract.

Horowitz, A.J., K.A. Elrick, J.A. ROBBINS, and R.B. Cook. A summary of the effects of mining and related activities on the sediment-trace element geochemistry of Lake Coeur d'Alene, Idaho, USA. Journal of Geochemical Exploration 52:135-144 (1995).

During 1989 and 1990 a series of 12 gravity cores, and 150 surface grab samples were collected in Lake Coeur d'Alene, Idaho to determine trace element concentrations, partitioning and surface and subsurface distribution patterns in the bed sediments of the lake. In addition, selected subsamples from one core were analyzed for 137Cs activity to begin to establish a trace element geochemical history for the lake. The intent was to try and relate the trace element concentrations and distributions in the sediment column to past and present mining and mining related activities in the area. Substantial portions of the surface and near-surface sediments in Lake Coeur d'Alene are markedly enriched in Ag, As, Cd, Hg, Pb, Sb and Zn, and somewhat enriched in Cu, Fe, and Mn. Surface distribution patterns, as well as variations in the thickness of the trace element-rich subsurface sediments, indicate that the source of much of this enriched material is the Coeur d'Alene River. The similarity between the trace element-rich surface and subsurface sediments with respect to: their location, their bulk chemistry, and their trace element partitioning indicate that the sources and/or concentrating mechanisms causing the trace element enrichment in the lake sediments probably have been the same throughout their depositional history. An estimated 75 million metric tons of trace element-rich sediments have been deposited on or in the lakebed. Based on a Mt. St. Helens' ash layer from the 1980 eruption, ages estimated from 137Cs activity, and the presence of 80 discernible and presumably annual layers in a core collected near the Coeur d'Alene River delta, indicate that the deposition of trace element-rich sediments began, at least in the Coeur d'Alene River delta, sorne time between 1895 and 1910, dates consistent with the onset of mining and ore-processing activities that began in the area in the 1880's.

Horowitz, A.J., K.A. Elrick, J.A. ROBBINS, and R.B. Cook. Effect of mining and related activities on the sediment trace element geochemistry of Lake Coeur d'Alene, Idaho, USA - Part II: Subsurface sediments. Hydrological Processes 9:35-54 (1995).

During the summer of 1990, 12 gravity cores were collected in Lake Coeur d'Alene, Idaho at various depths and in a variety of depositional environments. All core subsamples were analyzed to determine the bulk sediment chemistry; selected subsamples were analyzed for trace element partitioning and 137Cs activity. The purpose of these analyses was to deterimne the trace element concentrations and distributions in the sediment column and to try to establish trace element goechemical history of the lake in relation to mining and mining-related discharge operations in the area. Substantial portions of the near-surface sediments in Lake Coeur d'Alene are markedly enriched in Ag, As, Cd, Hg, Pb, Sb, and Zn, and slightly enriched in Cu, Fe, and Mn. Variations in the thickness of the trace element-rich sediments, which range from more than 119 cm to as little as 17 cm, indicate that the source of much of this material is the Coeur d'Alene River. An estimated 75 million tonnes of trace element-rich sediments have been deposited on or in the lake bed. Estimated trace element masses in excess of those considered representative of background conditions range from a high of 468,000 tonnes of Pb to a low of 260 tonnes of Hg. The similarity between the trace element-rich surface and subsurface sediments with respect to their location, their bulk chemistry, their interelement relations, and their trace element partitioning indicate that the sources and/or concentrating mechanisms causing the trace element enrichment in the lake sediments have probably been the same throughout their depositional history. Based on Mt. St. Helens' ash layer from the 1980 eruption, ages estimated from 137Cs activity and the presence of 80 discernible and presumably annual layers in a core collected near the Coeur d'Alene River delta indicate that deposition rates for the trace element-rich sediments have ranges from 2.1 to 1.3 cm/year. These data also indicate that the deposition of trace element-rich sediments began, at least in the Coeur d'Alene River delta, some time between 1895 and 1910, dates consistent with the onset of mining and ore processing activities that began in the area in the 1880s.

Kelley, J.G., C.J. Yen, J.S. Hobgood, D.J. SCHWAB, and K.W. Bedford. Short-term forecasts for Lake Erie. Proceedings, 1994 Hydraulic Engineering Conference, G.V. Cotroneo and R.R. Rumer (eds.), Buffalo, NY, August 1-5, 1994. American Society of Civil Engineers, New York, NY, 227-231 (1994).

Short-term forecasts for Lake Erie were generated by coupling a mesoscale atmospheric prediction system with a lake forecast system. The modeling systems used were The Pennsylvania State University/National Center for Atmospheric Research (NCAR) mesoscale atmospheric prediction system, version 4.8 and the Great Lakes Forecasting System (GLFS). Two one-way coupled model runs were conducted for Lake Erie using archived 36-hour forecast output from the Penn State/NCAR model in GLFS. High-resolution (2 km) hourly lake forecasts of currents, thermal structure and surface water elevations were generated for Lake Erie out to 36 hours. The surface water elevation and water temperature forecasts were compared against observed values at selected sites.

KUKKONEN, J., and P.F. LANDRUM. Effects of sediment-bound Polydimethylsiloxane (PDMS) on the bioavailability and distribution of Benzo(a)pyrene in lake sediment to Lumbriculus variegatus. Environmental Toxicology and Chemistry 14(3):523-531 (1995).

Oligochaetes, Lumbriculus variegatus, were exposed to Lake Michigan sediment spiked in the laboratory with polydimethylsiloxane (PDMS) at two different concentrations (50 and 150 mg g-1). Additionally, these sediment samples and one without PDMS were spiked with benzo(a)pyrene (BaP) (about 190 mg g-1). The accumulation of PDMS and BaP, survival, wet weight, and defecation of the animals were monitored. Lumbriculus variegatus accumulated sediment-associated BaP rapidly and achieved steady state within 96 to 168 h. The BaP uptake clearances (ks, g sediment g-1 animal h-1) were 0.069, 0.060, and 0.056 for BaP only, BaP with low-dose PDMS, and BaP with high-dose PDMS exposures, respectively. The BaP bioaccumulation factor was reduced by PDMS in the sediment. Only very low concentrations of PDMS were found associated with the worms, which suggests some surface sorption or association with material in the gut. Elimination of BaP in clean sediment was rapid, but elimination in water was much slower. Elimination rate constants for BaP, ke, were 0.0229 ± 0.0011 h-1 for sediment and 0.0004 ± 0.0004 h-1 water-only depuration. The PDMS was excreted within 10 h both in sediment and water-only depuration exposures, indicating that most of the measured body burden was due to the sediment-associated material inside the organisms' gut. Animals were not purged before analyses, and several approaches were investigated for estimating the contribution of the intestinal contents. Based on both measurements and calculations, sediment-associated BaP in the gut contributes less than 10% of total body burden. Thus, a 10-h water-only purge was found to be the most appropriate method for eliminating the gut-content influence on the body burden.

KUKKONEN, J., and P.F. LANDRUM. Measuring assimilation efficiencies for sediment-bound PAH and PCB congeners by benthic organisms. Aquatic Toxicology 32:75-92 (1995).

Assimilation ef'ficiencies (AEs) of sediment-sorbed 3H-benzo(a)pyrene (BaP) and 14C-2,2',4,4',5,5'-hexachlorobiphenyl (HCBP) were measured in Diporeia spp. (Amphipoda) and the AE for BaP was determined in Lumbriculus variegatus (Oligochaeta). For Diporeia, three methods of determining AEs were compared and for L. variegatus AEs were measured by two methods. The first method used organic carbon as a tracer based on a feeding selectivity index (Sl) and the relative concentrations in the sediment and fecal material. After 10-day exposure, the AEs in Diporeia for BaP and HCBP were 45% to 57% and 46% to 58%, respectively. The AEs in L. variegatus for BaP were 0% to 26% throughout the 5-day exposure. The second method estimated assimilation from ingestion based on the feeding rate and the SI for organic carbon. The AEs in Diporeia for BaP and HCBP were 11 to 15% and 36% to 52%, respectively. For the third approach, a dual-label technique was used with 14C-polydimethylsiloxane as a non-assimilated tracer for estimating AE based on the relative ratio of the assimilated and non-assimilated tracers in the food and fecal material. This technique gave a BaP-AE of 56% for Diporeia after 10 days. The BaP-AE in L. variegatus ranged from 23% to 26% for the first day of exposure, then decreased to 10% by the end of the 5-day exposure period. Differences in the AEs for Diporeia exposed to BaP determined from these techniques result, in part, from the differential distribution of the xenobiotics among the sediment particles and the selective feeding by Diporeia.

Kunkel, K.E., S.A. Changnon, T.E. CROLEY, and F.H. QUINN. Scenarios for climate change impacts assessments in the Great Lakes region. Ninth Conference on Applied Meteorology, Dallas, TX, January 15-20, 1995. American Meteorological Society, Boston, MA, 212-216 (1995).

No abstract.

LANDRUM, P.F. How should numerical sediment quality criteria be used? Human and Ecological Risk Assessment 1(1):13-17 (1995).

No abstract.

LANDRUM, P.F. Toxicokinetics from aqueous and sediment exposures for Diporeia spp. NOAA Technical Memorandum ERL GLERL-87, Great Lakes Environmental Research Laboratory, Ann Arbor, MI (PB95-240529/XAB) 17 pp. (1995). https://www.glerl.noaa.gov/pubs/tech_reports/glerl-087/tm-087.pdf

This report contains a summary of the toxicokinetics data for the amphipod Diporeia spp. from the last 13 years. Data are from both aqueous and sediment exposures and are focused primarily on selected polycyclic aromatic hydrocarbons and polychlorinated biphenyls.

LANDRUM, P.F., W.S. DUPUIS, and J. KUKKONEN. Toxicokinetics and toxicity of sediment-associated pyrene and phenanthrene in Diporeia spp.: Examination of equilibrium-partitioning theory and residue-based effects for assessing hazard. Environmental Toxicology and Chemistry 13(11):1769-1780 (1994).

The amphipod Diporeia spp. was exposed to pyrene (0.14 to 1.11 mmol g-1) or phenanthrene (0.08 to 0.62 mmol g-1)-dosed sediments for month-long exposures. Phenanthrene was only slightly toxic with 12±0 3% mortality at the highest sediment dose (0.62 mmol g-1). Failure to attain and maintain toxic residue body burdens, based on a nonpolar narcosis concentration of approximately 6 mmol g-1, accounts for the low mortality. Phenanthrene toxicokinetic parameters were essentially constant among all doses and consistent with previous measures. Sediment concentration was a poor representation of dose for mortality by pyrene. The relative pyrene distribution among the <63 mm particles increased in the smallest-sized particles at larger doses. An apparent stimulation of pyrene accumulation was observed as a peak in uptake clearance values between sediment concentrations of 0.16 and 0.26 mmol g-1 dry sediment. (Uptake clearance is the amount of source scavenged of contaminant per mass of organism per time.) The pyrene particle-size distribution and the varation in kinetics with dose provide a partial explanation for the poor representation of dose by the sediment concentration. The pyrene body burdens provided a good dose response yielding LD50 values of 6.3 (4.6-41.7, 95% C.I.) and 9.4 (7.9-54.2) umol g-1 for two experiments. These values are consistent with the residue concentrations for 50% mortality by a nonpolar narcosis mechanism. Comparing the experimental and predicted equilibrium partitioning-based sediment concentrations for 50% mortality, the equillibrium prediction overestimates the toxic pyrene sediment concentration by approximately a factor of ten. Diporeia behavior, differential particle-size distribution, and kinetic limitations appear as likely reasons for the variation between calculated and observed concentrations required to produce mortality.

LANDRUM, P.F., and W.R. FAUST. The role of sediment composition on the bioavailability of laboratory-dosed sediment-associated organic contaminants to the amphipod Diporeia (spp.). Chemical Speciation and Bioavailability 6(2/3):85-92 (1994).

Bioavailability of sediment-associated contaminants depends on contaminant and sediment characteristics and organism behavior and physiology. Bioavailability of a sediment-associated contaminant can be defined by the uptake clearance. Uptake clearance is the volume or mass of the source compartment scavenged of contaminant per mass of organism per time. For non-polar organic contaminants, carbon normalization has been suggested as a means of normalizing the relative bioavailability among sediments of differing compositions. To examine this, amphipods, Diporeia spp., were exposed to five Lake Michigan sediments and one soil from Florissant, MO, each spiked with selected polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) congeners. The uptake clearances (ks) were then determined. The PAH congeners were generally less bioavailable, based on ks, than the PCB congeners after accounting for contaminant hydrophobicity. The ks values generally declined as the fraction of fine particles (<63 mm) and organic carbon increased among the sediments. Organic carbon normalization reduced the variability among the ks values to approximately a factor of two among the Lake Michigan sediments, but the Florissant soil was an outlier. The compounds were more bioavailable from the Florissant soil than from the Lake Michigan sediments, and the relative availability increased with increasing contaminant hydrophobicity up to a factor of eight for hexachlorobiphenyl.

LEE, D.H., and A.H. CLITES. Great Lakes water level extremes and risk assessment. Proceedings, First International Conference, Water Resources Engineering Division of ASCE, San Antonio, TX, August 14-18, 1995. 129-133 (1995).

A method for developing Great Lakes probabilistic monthly water level forecasts, adapted from the Extended Streamflow Prediction technique is presented. The method is applied retrospectively to quantify the risk of flooding at Milwaukee, Wisconsin and assess the need to enhance flood control measures during a period of record high water levels. The results show that during the 24 months following October, 1986, when Lake Michigan reached an all time high, the risk of exceeding the maximum flood protection level of 177.76 m was less than 2%. This information would have reduced the uncertainty regarding the need to prepare a high lake level protection plan for downtown Milwaukee. Further refinements to the probabilistic forecast technique are discussed.

LIU, P.C. How do wind waves grow? Proceedings, Second International Conference on Air-Sea Interaction and on Meteorology and Oceanography of the Coastal Zone, Lisbon, Portugal, September 22-27, 1994. American Meteorological Society, 107-108 (1994).

No abstract.

LIU, P.C. Review of "Dynamics and Modeling of Ocean Waves" by G.J. Komen et al. Bulletin of the American Meteorological Society 76(5):763-766 (1995).

No abstract.

LOFGREN, B.M., and T.E. CROLEY. Validation of the Coupled Hydrosphere-Atmosphere Research Model (CHARM). Proceedings, Conference on Hydrology, Dallas, TX, January 15-20, 1995. American Meteorological Society, Boston, MA, 26-30 (1995).

No abstract.

Lohrenz, S.E., G.L. FAHNENSTIEL, and D.G. Redalje. Spatial and temporal variations of photosynthetic parameters in relation to environmental conditions in coastal waters of the northern Gulf of Mexico. Estuaries 17(4):779-795 (1994).

On a series of eight cruises conducted in the northern Gulf of Mexico, efforts were made to characterize temporal and spatial variability in parameters of the photosynthesis-irradiance saturation curve (PBmax, aB,Ik) and to relate the observed varaitions to environmental conditions. Experiments to examine the importance of diel variation in upper mixed layer populations were conducted in July-August 1990 and March 1991. During July-August 1990, PBmax and Ik showed significant increases and aB decreased during the photoperiod in both river plume and shelf-slope populations. During March 1991, no consistent covariance of P-I parameters with local time was found, although highest values of aB in the river plume were observed in early morning. Seasonal variation in PBmax and aB were correlated with temperature. Spatial variations of photosynthetic parameters in the upper mixed layer ranged from twofold to threefold within any given cruise. Variations of photosynthetic parameters in the upper mixed layer were related to principal components derived from environmental variables, including temperature, salinity, nutrients, mixed layer depth, attenuation coefficient, and daily photosynthetically available radiation (PAR). Greater than 70% of the variation in the environmental variables could be accounted for by two principal components; the majority of this variation was associated with the first principal component, which was generally strongly correlated with salinity, nutrients, mixed layer depth, and attentuation coefficient. Corelations of PBmax, aB, and Ik with the first principal component were found to be significant in some cases, an indication that spatial variability in P-I parameters was related to river outflow. Variation of P-I parameters in relation to depth and PAR were evaluated by regressions with principal components derived from depth, temperature, and mean daily PAR. For most cruises, PBmax and Ik were negatively correlated with the first principal component, which was strongly positively correlated with depth and negatively correlated with daily PAR. This was consistent with a decrease in both PBmax and Ik with depth that could be related to decreasing daily PAR. Positive correlations of aB with the first principal component for two cruises, March 1991 and April 1992, indicated an increasing trend with depth. In conclusion, relationships between P-I parameters and environmental variables in the region of study were significant in some cases, but variation between cruises made it difficult to generalize. We attributed this variation to the physically dynamic characteristics of the region and the possible effects of variables that were not included in the analysis such as species composition. Our findings do support the view that a limited set of observations may be adequate to characterize P-I parameter distributions in a given region within a restricted period of time.

Lohrenz, S.E., D.G. Redalje, and G.L. FAHNENSTIEL. Optical properties of Mississippi River plume and adjacent waters during March 1991. Proceedings, Nutrient Enhanced Coastal Ocean Productivity Synthesis Workshop, Baton Rouge, LA, April 26-27, 1994. Louisiana Sea Grant, Baton Rouge, LA, 67-74 (1995).

Variations in attenuation of irradiance (total photosynthetically active radiation and downwelling spectral irradiance) were related to other optical measurements (beam c, solar-stimulated fluorescence) and to concentrations of particulate and dissolved materials determined from analyses of discrete samples. Four sampling locations were studies representative of conditions ranging from very turbid low salinity plume water to very oligotrophic water over the slope. Highest values of Kpar (over 2.5 m-1) were observed at the surface in a low salinity plume station, although there was considerable scatter in the values. Lowest values were observed at a slope water station (<0.8 m-1). The utility of measurements of Lu683 as an index of chlorophyll concentrations was found to be limited. Extracted chlorophyll concentrations tended to be overestimated in near surface waters and underestimated at depth. Profiles of beam c revealed high values (>3 m-1) in surface waters of the shelf stations. Spectral attenuation minima at shelf stations were in the vicinity of 540-580 nm. Lowest values of attentuation were observed at the slope water station where the attentuation minimum was around 490 nm. A spectral attentuation model reproduced measured spectra remarkably well considerring variations in attenauation spanned over an order of magnitude. It was evident that in shelf waters during this period, absorption and scattering were dominated by dissolved organic carbon and suspended particulate matter.

Magnuson, J.J., C.J. Bowser, R.A. ASSEL, B.T. DeStasio, J.R. Eaton, E.J. Fee, P.J. Dillion, L.D. Mortsch, N.T. Roulet, F.H. QUINN, and D.W. Schindler. Region 1. - Laurentian Great Lakes and Precambrian Shield. Proceedings, Regional Assessment of Freshwater Ecosystems and Climate Change in North America, Leesburg, Virginia, October 24-26, 1994. American Society of Limnology and Oceanography, 3-4 (1994). https://www.glerl.noaa.gov/pubs/fulltext/1994/19940008.pdf

No abstract.

Meyers, P.A., A. Zsolnay, and B.J. EADIE. Pyrolysis-mass spectrometry of sediment trap organic matter from Lake Michigan. Chemical Speciation and Bioavailability 7(1):33-37 (1995).

The composition of total organic matter associated with sinking particles collected by sediment traps moored at five depths in Lake Michigan has been characterized by pyrolosis-chemical ionization mass spectrometry. Concentrations of organic carbon decrease dramatically in the upper part of the water column as organic matter is remineralized. Remineralization changes the character of organic matter associated with particles as they settle, and different pyrolsate distributions are consequently obtained. Nitrogen-containing compounds are more abundant in trap contents from the epilmnion and metalimnion, whereas saccharides and humic acids are more abundant in particles settling within the near-bottom nepheloid layer. Comparison of extractable n-alkane distributions to the pyrolysates of bulk organic matter indicates preferential degradation of algal components during sinking of sediment particles.

Mulsow, S.G., and P.F. LANDRUM. Bioaccumulation of DDT in a marine polychaete, the conveyor-belt deposit feeder Heteromastus filiformis (claparede). Chemosphere 31(4):3141-3152 (1995).

To better understand the fate of toxic pollutants within the sediment column and their uptake by the benthic community, the effects of several sub-lethal DDT concentrations were determined on Heteromastus filiformis (a marine head-down deposit feeder) under laboratory conditions. Net DDT uptake by this polychaete (measured at 5, 11, and 28 days) increased through time for all treatments (2, 4, and 8 mg g-1 DDT in sediments) and reached concentrations of 240, 500, and 870 mg of DDT per g of lipid, respectively, at the end of the experiment. Biota sediment accumulation factor (BSAF) for DDT (organism concentration normalized to lipid content divided by sediment concentration normalized to the sediment total organic carbon content) ranged from 0.4 to 0.8. Sediment reworking rate of H. filiformis measured by fecal pellet production was reduced only when the worms were exposed to the highest concentration (8 mg g-1 DDT after 28 d exposure). Initially, fecal pellets contained 5 to 8 times greater DDT concentrations than the spiked sediments, but these values decreased at 11 and 28 days. In this study, DDT reduced the feeding rate of H. filiformis at a relatively low DDT concentration (8 mg g-1), compared to concentrations reported for marine sediments, after a relatively short time (28 days), and the buried DDT was transported to the sediment-water interface through the fecal pellets.

NALEPA, T.F. Decline of native unionid bivalves in Lake St. Clair after infestation by the zebra mussel, Dreissena polymorpha. Canadian Journal of Fisheries and Aquatic Sciences 51(10):2227-2233 (1994).

To determine impacts of the zebra mussel, Dreissena polymorpha, on bivalves in Lake St. Clair, densities of Unionidae in 1990 and 1992 (after D. polymorpha invasion) were compared with densities in 1986 (before D. polymorpha). Declines in density occurred mainly at sites in the southeastern portion of the lake where unionids were highly infested with D. polymorpha. Unionid densities at highly infested sites declined from 2.4/m2 in 1986, to 1.8/m2 in 1990, and to 0/m2 in 1992. Unionid species with light-weight shells that brood larvae over an extended period declined more between 1986 and 1990 than heavy-shelled, short-term brooders. Unionid densities at lightly infested sites located mainly in the northwestern portion of the lake did not decline: mean densities were 1.4/m2 in 1986, 1.6/m2 in 1990, and 1.4/m2 in 1992. While the mean number of D. polymorpha per unionid was <l at these lightly infested sites in 1990, it increased to 35 by 1992. Given this relatively slow increase in D. polymorpha per unionid in this portion of the lake, continued monitoring of populations should provide a better understanding of the relationship between the extent of infestations and unionid mortality.

Nelsen, T.A., P. Blackwelder, T. Hood, C. Zarikian, J.H. Trefry, S. Metz, B.J. EADIE, and B.J. McKee. Retrospective analysis of NECOP area sediments: biogenic, inorganic, and organic indicators of antropogenic influences since the turn of the century. Proceedings, Nutrient Enhanced Coastal Ocean Productivity Synthesis Workshop, Baton Rouge, LA, April 26-27, 1994. Louisiana Sea Grant, Baton Rouge, LA, 90-101 (1995).

Surface and cored sediments from the NECOP study area were analyzed for physical (coarse-grain texture, composition), biological (foraminifera) and chemical (organic and inorganic) properties. Results of analyses for surface samples indicated spatial patterns of benthic foraminifera dictated by sediment accumulation rate and regions of seasonal hypoxia. The latter also correlated well with the distribution of surface authigenic glauconite. Temporal variability, determined from core samples, indicated transitions in benthic foraminifera community structure with upcore increases in hypoxia tolerant assemblages. Transitions in glauconite abundance, organic carbon, and other chemical paramaters strongly correlated temporally with increases in fertilizer application in the United States.

O'CONNOR, W.P. The complex wavenumber eigenvalues of Laplace's tidal equations for oceans bounded by meridians. Proceedings of the Royal Society of London, Series A 449:51-64 (1995).

The complex wavenumber eigenvalues of Laplace's tidal equations are determined for an ocean of constant depth bounded by meridians. A Galerkin method is used to expand the tide height and velocities in series of associated Legendre functions. A homogeneous system of equations results from the continuity and momentum equations. The frequency and depth are fixed, so that the meridional wavenumbers are the eigenvalues. This gives rise to a generalized eigenvalue problem that must be solved numerically by iteration. The eigenvalues are not integers and represent inertia-gravity wave solutions at the specified tidal forcing frequency that can be excited by the presence of meridional boundaries. Those complex eigenvalues represent solutions that decay away from meridional boundaries. The eigenvalue spectrum is investigated for the semi-diurnal, fortnightly, and monthly tides. One complex wavenumber for the semi-diurnal tide explains the amphidromic systems within 20° of a north-south coastline. The fortnightly and monthly tides have only real wavenumber eigenvalues. The basin scale deviation of these tides from equilibrium is attributed to low wavenumber divergent inertia-gravity waves.

QUINN, F.H., T.E. CROLEY, S.J. Changnon, and K. Kunkel. North American Great Lakes hydrology under the transposed 1993 Mississippi flood climate. Proceedings, Conference on Hydrology, Dallas, TX, January 15-20, 1995. American Meteorological Society, Boston, MA, 18-21 (1995).

No abstract.

Redalje, D.G., S.E. Lohrenz, and G.L. FAHNENSTIEL. The relationship between primary production and the vertical export of particulate organic matter in a river-impacted coastal ecosystem. Estuaries 17(4):829-838 (1994).

As part of the NOAA Nutrient Enhanced Coastal Ocean Productivity program, we have conducted four research cruises, July-August 1990, March 1991, September 1991, and May 1992, in the Mississippi River plume and adjacent shelf regions. Over this time period, photic-zone-integrated primary production varied significantly in both the river plume and shelf study regions, with greatest variability observed in the river plume region. In the river plume and the adjacent shelf, highest production occurred during July-August 1990 (8.17 g C m-2 d-1 for the plume and 1.89-3.02 g C m-2 d-1 for the shelf) and the lowest during march 1991 (0.40-0.69 g C m-2 d-1 for the plume and 0.12-0.45 g C m-2 d-1 for the shelf). The vertical export of POC from the euphotic zone, determined with free-floating MULTITRAP sediment trap systems, also varied temporally in both study regions, with highest values occurring in May 1992 (1.80 ± 0.04 g C m-2 d-1 for the plume and 0.40 ± 0.02 g C m-2 d-1 for the shelf) and the lowest values occurring during July-August 1990 (0.20 ± 0.02 g C m-2 d-1 for the plume and 0.18 ± 0 0.01 g C m-2 d-1 for the shelf). The fraction of production exported out of the photic zone was highly variable and was dependent, in part, on phytoplankton species composition and on the grazing activities of microzooplankton and mesozooplankton. The lowest ratio of export to production coincided with the time when production was greatest and the highest ratios occurred when production was the lowest.

REID, D.F. The Great Lakes Environmental Research Laboratory: Focus on Saginaw Bay. Proceedings, Ecosystem Management: Status and Potential, Washington, DC, March 24-25, 1994. U.S. Government Printing Office, Washington, DC, 153-158 (1994).

No abstract.

ROBBINS, J.A., and A.W. Jasinski. Chernobyl fallout radionuclides in Lake Sniardwy, Poland. Journal of Environmental Radioactivity 26:157-184 (1995).

Following the introduction of Chernobyl radionuclides, in May 1986, to Lake Sniardwy, the largest lake in Poland, sediment cores and fish were periodically collected through 1989 and analyzed for 144Ce, 134Cs and 137Cs. Within four months of the fallout 134Cs had penetrated down to about 10 cm in one sediment core and, in cores collected from three sites, a year later, had penetrated from 14 to 24 cm. Laboratory measurement of the partitioning of a carrier-free spike of 137Cs between sediment and pore water yielded a Kd of 4.3 x 103 ml g-1 ruling out molecular diffusion (Deff-0.06 cm2 year-1) as a significant transport mechanism. Rapid vertical transport is ascribed to mixing through strong coupling of wind-driven currents to sediments in this shallow, polymictic lake (5.8 m mean depth) and to biological activity. Profiles of 134Cs at several sites and changes in profiles over three years at one site were described by eddy diffusive mixing (3-20 cm2 year-1) of a layer of activity initially deposited on the sediment surface. The generally discontinuous nature of profiles of 144Ce is ascribed to its association with discreet 'hot' (nuclear fuel) particles. The average activity of 137Cs in the flesh of bream (Abramis brama) increased up to 120 times that of pre-Chernobyl levels (measured in 1985) 1 year after the fallout event. The delayed maximum and subsequent decrease in 137Cs activity are described by a first order kinetic model with an uptake rate constant proportional to the time-dependent concentration of the isotope in surface sediments. Model calculations are substantially improved if the uptake rate constant includes a term, measuring the 'availability' of 137Cs to fish, calculated in terms of radial diffusion of radiocesium into sediment particles. The inferred residence time of 137Cs in bream was about 1 year.

Schloesser, D.W., and T.F. NALEPA. Dramatic decline of unionid bivalves in offshore waters of western Lake Erie after infestation by the zebra mussel, Dreissena polymorpha. Canadian Journal of Fisheries and Aquatic Sciences 51:2234-2242 (1994).

Unionid bivalves and attached epizoic zebra mussels (Dreissena polymorpha) were collected at one index station in 1989, 1990, and 1991 and at 17 stations in 1991 in offshore waters of western Lake Erie of the Laurentian Great Lakes. Sampling at the index station revealed that the proportion of live unionids declined from 53% in September 1989 to 17% in May-June 1990 and to 0% in September 1990: this100% mortality coincided with heavy infestation by zebra mussels. Quantitative sampling with a Ponar grab at the 17 stations in 1991 revealed a widespread and dramatic reduction in unionid populations. In 1982, five unionid species occurred at 35% of the stations at a density of 4/m2, whereas in 1991, no live unionid species were found. Qualitative sampling with an epibenthic sled at the 17 stations in 1991 yielded only 4 live specimens of 2 species (Amblema plicata plicata and Fusconaia flava) and 187 dead specimens of 10 species. These and other results indicate that unionid populations are being negatively affected by zebra mussels in the Great Lakes. Similar impacts on unionids are expected to occur where zebra mussels become abundant throughout North America.

Schloesser, D.W., and T.F. NALEPA. Freshwater mussels in the Lake Huron-Lake Erie corridor. In Our Living Resources: A Report to the Nation on the Distribution, Abundance, and Health of U.S.Plants, Animals, and Ecosystems, E.T. Laroe, G. S. Farris, C.E. Puckett, P. Doran, and M.J. Mac (eds.). U.S. Dept. of the Interior, National Biological Service, Washington, DC, 179-182 (1995).

No abstract.

SCHWAB, D.J., K.W. Bedford, and F.H. QUINN. Overview of the Great Lakes Coastal Forecasting System. Proceedings, 11th International Conference on IIPS for Meteorology, Oceanography, and Hydrology, Dallas, TX, January 15-20, 1995. American Meteorological Society, Boston, MA, 132-133 (1995).

No abstract.

SCHWAB, D.J., W.P. O'CONNOR, and G.L. Mellor. On the net cyclonic circulation in large stratified lakes. Journal of Physical Oceanography 25(6):1516-1520 (1995). https://www.glerl.noaa.gov/pubs/fulltext/1995/19950003.pdf

This paper proposes a possible explanation for the mean cyclonic circulation in large stratified lakes. The condition of no heat flux through the bottom boundary causes the isotherms to dip near the shores to itersect the sloping bottom orthogonally. This "doming" of the thermocline causes an internal pressure gradient in the surface layer with higher pressure nearshore and results in a geostrophic cyclonic circulation.

SELLINGER, C.E. Groundwater flux into a portion of eastern Lake Michigan. Journal of Great Lakes Research 21(1):53-63 (1995). https://www.glerl.noaa.gov/pubs/fulltext/1995/19950004.pdf

One of the world's most precious resources is groundwater. Groundwater flow in the Great Lakes region is estimated to be 111.7 million m3 d-1. Not only is groundwater's value in the Great Lakes region attributed to its comsumptive quality, but groundwater is also important to the hydrologic cycle in the region. The objective of this study is to quantify the volume of groundwater by applying streamflow. This study compares the past method of computing groundwater flow with results obtained from a three-dimensional finite-difference model.

Trefry, J.H., S. Metz, T.A. Nelsen, T.P. Trocine, and B.J. EADIE. Transport and fate of particulate organic carbon by the Mississippi River and its fate in the Gulf of Mexico. Estuaries 17(4):839-849 (1994).

This study was designed to determine the amount of particulate organic carbon (POC) introduced to the Gulf of Mexico by the Mississippi River and assess the influence of POC inputs on the development of hypoxia and burial of organic carbon on the Louisiana continental shelf. Samples of suspended sediment and supporting hydrographic data were collected from the river and >50 sites on the adjacent shelf. Suspended particles collected in the river averaged 1.8 ± 0.3% organic carbon. Becuse of this uniformity, POC values (in mmol l-1) correlated well with concentrations of total suspended matter. Net transport of total organic carbon by the Mississippi-Atchafalaya River system averaged 0.48 x 1012 moles y-1 with 66% of the total organic carbon carried as POC. Concentrations of POC decreased from a high as 600 mmol l-1 in the river to <0.8 mmol l-1 in offshore waters. In contrast, the organic carbon fraction of the suspended matter increased from <2% of the total mass in the river to >35% along the shelf at 10 km from the river mouth. River flow was a dominant factor in controlling particle and POC distributions; however, time-series data showed that tides and weather fronts can influence particle movement and POC concentrations. Values for apparent oxygen utilization (AOU) increased from ~60 mmol l-1 to >200 mmol l-1 along the shelf on approach to the region of chronic hypoxia. Short-term increases in AOU were related to transport of more particle-rich waters. Sediments buried on the shelf contained less organic carbon than incoming river particles. Organic carbon and d13C values for shelf sediments indicated that large amounts of both terrigenous and marine organic carbon are being decomposed in shelf waters and sediments to fuel observed hypoxia.

VANDERPLOEG, H.A., J.R. LIEBIG, and T.F. NALEPA. From picoplankton to microplankton: temperature-driven filtration by the unionid bivalve Lampsilis radiata siliquoidea in Lake St. Clair. Canadian Journal of Fisheries and Aquatic Sciences 52:63-74 (1995).

Size-selective filtration by the unionid bivalve Lampsilis radiata siliquoidea was determined seasonally for Lake St. Clair seston with special emphasis placed on determining retention efficiency of particles less than 1 mm equivalent spherical diameter (ESD). These results allowed us to estimate the aggregate clearance rates of Lampsilis and total unionids in the lake. Retention efficiency for seston in the 0.79-1.00 mm ESD size category was 0.44 whereas 0.07 was the corresponding value for O.91-mm microspheres in laboratory prepared mixtures of microspheres and cultured algae; respective values for the 0.63-0.79 mm size category were not significantly different from zero. Particle shape may explain the difference between natural seston and microspheres. Particles in the picoplankton size range (<3 mm ESD) were probably an important food resource to the mussels, since 35-49% of the seston volume in Lake St. Clair was smaller than 3 mm ESD. Regression analyses of filtration rate as a function of temperature and food concentration showed that feeding rate was temperature driven and not saturated by available seston concentration. Lampsilis and total community clearance rates were maximum in September, with respective fractions of the water columns swept clear of 0.018 and 0.053 d-1.

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