GLERL Publications Abstracts: FY 1990

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

Barron, M.G., G.R. STEHLY, and W.L. Hayton. Pharmacokinetic modeling in aquatic animals. I. Models and concepts. Aquatic Toxicology 17:187-212 (1990).

While clinical and toxicological applications of pharmacokinetics have continued to evolve both conceptually and experimentally, pharmacokinetic modeling in aquatic animals has not progressed accordingly. In this paper we present methods and concepts of pharmacokinetic modeling in aquatic animals using multicompartmental, clearance-based, non-compartmental and physiologically-based pharmocokinetic models. These models should be considered as alternatives to traditional approaches, which assume that the animal acts as a single homogeneous compartment based on apparent monoexponential elimination. Multicompartmental models are a necessary increase in complexity when elimination is biphasic or when there is a widely different distribution between high perfusion and low perfusion tissues. Alternatives to traditional rate-constant based models are clearance-based compartmental models, which have parameters that may be interpreted in terms of the controlling physiological and biochemical processes. Non-compartmental methods characterize uptake, distribution, elimination, and persistence without making assumptions about the underlying model topology. Development of physiologically-based models is highly desirable because they allow extrapolation to other species, body sizes and environmental conditions.

Bedford, K.W., and D.J. SCHWAB. Preparation of real-time Great Lakes forecasts. Cray Channels Summer 1990:14-17 (1990).

No abstract.

Bedford, K.W., C.-C Yen, J. Kempf, D.J. SCHWAB, R. Marshall, and C.A. Kuan. A 3D-Stereo graphics interface for operational Great Lakes forecasts. Proceedings, Estuarine and Coastal Modeling Conference, Newport, RI, November 15-17, 1989. American Society of Civil Engineers, 248-257 (1990).

A system for real-time predictions of Great Lakes physics and transport characteristics is now being implemented. The full 3-D nature of the predictions demands accurate, high speed computer visualized representations of the results and therefore this article presents the user interface for this system which fully integrates a graphics philosophy at every level of the forecasting system. Steering, tracking and pre- and post processing are possible and the full use of 3-D stereo animations is being exploited to the extent of its utility.

BRATKOVICH, A.W. NOAA ship requirements for fisheries oceanography. NOAA's Ocean Fleet Modernization Study Phase 1: Mission Requirements. NOAA, Washington, DC, A69-73 pp. (1990).

No abstract.

CARRICK, H.J., and G.L. FAHNENSTIEL. Biomass, size structure, and composition of phototrophic and heterotrophic nanoflagellate communities in Lakes Huron and Michigan. Canadian Journal of Fisheries and Aquatic Sciences 46(11):1922-1928 (1989).

The abundance and biomass of surface (5 m) and deep (20-45 m) nanoflagellate communities in Lakes Huron and Michigan were determined during 1987. Abundances (102-10-3cells.mL-1) were comparable between lakes and similar to those reported from other oligotrophic environments. Community composition was skewed towards the small end of the size spectrum due to the prevalence of small chrysomonads. In general, heterotrophic flagellates (Hnano) were more abundant that phototrophic flagellates (Pnano), while standing stocks of Pnano carbon (average 24.7 mg C.L-1) were greater than Hnano carbon (9.6 mg C.L-1) on nearly all sample dates. The abundance of nanoflagellates in both Lakes Huron and Michigan peaked in July, perhaps indicating increased growth at higher temperatures and/or a response to higher abundance of prey. Nanoflagellate communities in deep waters during thermal stratification were more abundant (50-70% higher carbon) than surface communities and were dominated by Pnano. High carbon standing stocks of deep communities did not correspond with high prey abundances. Thus, deep communities seem to be influenced by factors (e.g., light and nutrients) that maintain deep phytoplankton communities in the upper Great Lakes. While Hnano are quantitatively important in Lakes Huron and Michigan, representing nearly 20% of phytoplankton biomass, their trophic role is largely unknown.

CARRICK, H.J., and G.L. FAHNENSTIEL. Planktonic protozoa in Lakes Huron and Michigan: Seasonal abundance and composition of ciliates and dinoflagellates. Journal of Great Lakes Research 16(2):319-329 (1990).

The abundance and biomass of surface (5m) and deep (30-45m) ciliate and dinoflagellate protozoa in the offshore waters of Lakes Huron and Michigan were determined from December 1986 to November 1987. Protozoan (ciliates and dinoflagellates) abundance (4 to 15 cells.mL-1) and biomass (13-140 mg.L-1, wet wt.) were comparable between lakes and similar to those reported from other oligotrophic environments. On average, ciliates comprised the majority of protozoan abundance (80%) and biomass (73%). The mean size (ESD) of these communities was small (20.6 mm) due to the numerical dominance of small choreotrichs, oligotrichs, and species of Gymnodinium. Total biomass in both lakes peaked during late June-July and again during the October-November period. These seasonal changes in biomass were accompanied by species replacements: tintinnids, strobilids, oligotrichs, and Gymnodinium species were abundant in the spring isothermal period, shifting to oligotrich dominance during summer stratification (May-July); a more diverse assemblage followed during late stratification (October-November) in which haptorids, prorodontids, and Peridinium species became more important. Deep and surface communities were comparable in terms of abundance and biomass, although deep community biomass decreased as stratification intensified. Because the biomass of ciliates alone represents approximately 30% of crustacean zooplankton biomass, protozoa may be more important grazers than once thought.

Chin, Y.-P, W.J. Weber, and B.J. EADIE. Estimating the effects of dispersed organic polymers on the sorption of contaminants by natural solids. 2. Sorption in the presence of humic and other natural macromolecules. Environmental Science and Technology 24(6):837-842 (1990).

A triphase distribution model was used in conjunction with experimental observations to characterize the effects of humic polymers dispersed in an aqueous phase on the sorption of hydrophobic organic compounds from that phase by natural solids. The organic compound-humic substance binding constants employed in the model were estimated using a partition equation that takes into account the solubility of the solute in both the aqueous and organic polymer phases as developed in the first paper of this two part series. Experimental results and model predictions indicate that the sorption of moderately hydrophobic compounds by lacustrine sediments is relatively unaffected by the presence of humic polymers, but that the sorption of highly insoluble organic contaminants by the same sorbents is sensitive to small amounts of background organic polymers. The observations support earlier analyses by other investigators regarding the impact of the organic subphases on the fate and transport of pollutants in natural aquatic systems.

CROLEY, T.E.II. Great Lakes hydrological impacts of 2xCO2 climate change. Proceedings, International and Transboundary Water Resources Issues, Toronto, Ontario, Canada, April 1-5, 1990. American Water Resources Association, Minneapolis, MN, 595-604 (1990).

The Great Lakes Environmental Research Laboratory considered climate change impacts on North American Great Lakes hydrology by using recent atmospheric general circulation model (GCM) simulations of a doubling of atmospheric CO2, available from the Goddard Institute for Space Studies. We made changes in historical meteorological data, similar to the changes observed in the GCM, and observed the impact of the changed data in hydrology models for basin moisture storage and runoff, over-lake precipitation, and lake heat storage and evaporation. While precipitation changes are uncertain, higher air temperatures generally increase basin evapotranspiration which decreases the snowpack, lowers runoff, shifts runoff peaks, and reduces soil moisture. There are larger amounts of heat resident in the deep lakes reducing buoyancy-driven turnovers of the water column, lowering ice formation, and increasing lake evaporation.

CROLEY, T.E., II, and H.C. HARTMANN. GLERL's near real time hydrological outlook package. Proceedings, Great Lakes Water Level Forecasting and Statistics Symposium, Windsor, Ontario, Canada, May 17-18, 1990. Great Lakes Commission, Ann Arbor, MI, 63-72 (1990).

The Great Lakes Environmental Research Laboratory developed a semiautomatic software package for making deterministic or probabilistic outlooks of basin moisture storage conditions, basin runoff, lake heat storage, lake evaporation and other heat fluxes, net lake supplies, and lake levels six or more full months into the future for large lakes. We designed the package especially for use on small computers with a standard FORTRAN-77 compiler, 5-15 megabytes of disk storage (per application), and a minimum of processor and memory resources. The package combines our Large Basin Runoff Model applications on each of the subbasins about a-lake to represent the entire basin's current moisture storage and our lake evaporation model applications on each of the Great Lakes to represent each lake's current heat storage. Our near-real-time data reduction system uses new algorithms to efficiently determine daily areal averages of meteorologic variables over each of the subbasins. We select historic meteorologic sequences, representing anticipated meteorology, based on the National Weather Service monthly and seasonal forecasts of precipitation and air temperature probabilities, for use with the runoff and evaporation models to generate our near real-time outlooks. The package construction is presented and the use of its modules are detailed.

EADIE, B.J., N.R. MOREHEAD, and P.F. LANDRUM. Three-phase partitioning of hydrophobic organic compounds in Great Lakes waters. Chemosphere 20(1-2):161-178 (1990).

Great Lakes waters were freshly collected, inoculated with radiolabelled hydrophobic organic compounds and, after equilibration, separated into particle bound, dissolved organic matter bound and freely dissolved phases. In these ambient suspended matter (0.2-5 ppm) and dissolved organic carbon (1-6 ppm) media, the freely dissolved phase generally dominates and the amounts associated with dissolved organic matter rarely exceeds 5% for most compounds. Solubility controls the constituent distribution between particle bound and freely dissolved but plays a much smaller role in mediating the binding to dissolved organic matter. Differences observed in the binding to dissolved and particulate organic matter support the need to consider the distribution of constituents among three phases. Although the concentration and composition of the substrate changes significantly, there is no apparent seasonal effect on the distribution of compounds among the three phases in the Great Lakes.

EADIE, B.J., H.A. VANDERPLOEG, J.A. ROBBINS, and G.L. BELL. Significance of sediment resuspension and particle settling. In Large Lakes: Ecological Structure and Function, M.M. Tilzer and C. Serruya (eds.). Springer-Verlag, New York, 196-209 (1990).

Seasonal particle characteristics and sediment-trap-measured resuspension rates are examined for the Laurentian Great Lakes and compared with other large, deep lakes. Results are used to estimate the influence of particle-related processes on the current chemical composition of these lakes. Even in deep systems, such as the Laurentian Great Lakes, particle settling times are relatively short and compounds with a high affinity for particulate matter are efficiently scavenged and removed to the sediments. After reaching the bottom, the settled materials are mixed by the feeding activities of bottom-dwelling organisms into an homogenized pool representing years-to-decades of recent sedimentation. It is apparent from the relatively slow decline of the concentrations of these particle-associated constituents in water and biota that sediments are a leaky sink; small concentrations persist for decades because of processes that can remobilize materials from the bottom.

Edgington, D.N., and J.A. ROBBINS. Time scales of sediment focusing in large lakes as revealed by measurement of fallout Cs-137. In Large Lakes: Ecological Structure and Function, M.M. Tilzer and C. Serruya (eds.). Springer-Verlag, New York, 210-223 (1990).

The sediments of large lakes provide a sink for many of the trace contaminant's that have been mobilized in the environment. Several models have been developed to describe the resultant concentration profiles in sediment cores in terms of input fluxes, sedimentation rates, and mixing depths. Implicit in these models are the assumptions that sedimenting particles are disconnected from prior input events and that transport is only by vertical advection, even though the measured integrated fluxes indicated that there had been considerable sediment focusing. Recent measurements of Cs-137 and Pb-210 in sediment cores from Green Bay in Lake Michigan and least-squares best fits for sedimentation rates and mixing depths from these data suggest that these simple models are incorrect and do not adequately reflect the resuspension, horizontal transport, and redeposition of bottom sediments. Furthermore, such processes are not confined to shallow water; a comparison of total Cs-137 content, sedimentation rates, and mixing depths measured in a series of cores taken from Lake Michigan at the same locations ten years apart indicate that while the overall integrated Cs-137 content of the sediments, corrected for radioactive decay, has remained constant, there has been an increase within and a decrease at the periphery and outside of the depositional zones over the same period there was, as would be predicted from the simple models, an increase in the thickness of the measured mixing depth.

FAHNENSTIEL, G.L., C.L. Schelske, and M.J. McCORMICK. Phytoplankton photosynthesis and biomass in Lake Superior: Effects of nutrient enrichment. Verhandlugen Internationale Vereinigung Fur Theoretische und Angewandte Limnologie 24:371-377 (1990).

Several investigators have measured the rate of photosynthesis in Lake Superior during the past two decades (Putnam and Olson 1966, Parkos et al. 1969, Verduin 1975, Nalewajko et al. 1981, Fanhenstiel & Glime 1983, Nalewajko & Voltolina 1986). Neither experimental approaches nor methods for data reporting have been consistent among investigators (Fahnenstiel et al. 1989) and thus, not all rates are comparable. Furthermore, the factor(s) controlling the rate of photosynthesis in Lake Superior may still be open to question. The role of nutrients and in particular, phosphorus, in controlling photosynthesis and phytoplankton yield in Lake Superior has been documented. Schelske et al. (1972) performed a series of large enclosure experiments that were designed to determine the limiting element in the Great Lakes. In these experiments, large volumes of water (> 1000 I) were spiked with various combinations of plant nutrients and the response of the phytoplankton community in terms of chlorophyll, phytoplankton abundance, and photosynthesis was monitored. Results from these experiments suggested that phosphorus was the limiting element in the Great Lakes. These and other nutrient enrichment studies on the Great Lakes (Schelske 1979) provided the scientific cornerstone for eutrophication control.

FONTAINE, T.D., III, and D.J. Stewart. Trophic dynamics and ecosystem integrity in the Great Lakes: Past, present, and possibilities. In An Ecosystem Approach to the Integrity of the Great Lakes in Turbulent Times, C.J. Edwards and H.A. Regier (eds.). Great Lakes Fishery Commission Special Publication 90-4, 153-167 (1990).

The Great Lakes are perhaps unique among large lakes of the world in the degree to which fish population dynamics and water quality resources can be influenced by management at the bottom of the food web or from the top of the food web. Nonmanagement factors known to affect fish quality and quantity and water quality include toxic contaminants, short-term weather events and long-term climatic changes, exotic species invasions, and evolutionary changes of existing species. Because fisheries-based revenues to the Great Lakes region are presently estimated at $2-4 billion per year, it would seem prudent to determine the extent to which management and nonmanagement factors influence fish quality and quantity, as well as water quality. Here we present a comprehensive, yet preliminary, conceptual and mathematical modeling approach that describes causal relationships among fish food web, nutrient cycling, and contaminant processes in the southern basin of Lake Michigan. Our approach identifies weaknesses in the data base that are important to the predictive usefulness of such a model. We suggest that our comprehensive modeling approach will be useful in transforming some surprises into expected events. For instance, the model predicts that contaminant concentrations in salmonines will decrease by nearly 20% if Bythotrephes, an exotic carnivorous zooplankton, successfully establishes itself in Lake Michigan.

GARDNER, W.S., P.F. LANDRUM, and J.F. CAVALETTO. Lipid-partitioning and disposition of benzo(a)pyrene and Hexachlorobiphenyl in Lake Michigan Pontoporeia hoyi and Mysis relicta. Environmental Toxicology and Chemistry 9:1269-1278 (1990).

Two Lake Michigan macroinvertebrates, Pontoporeia hoyi and Mysis relicta, exhibited major differences in the disposition of the lipophilic contaminants, [3 H]benzo[a]pyrene (BaP) and [14C]2,4,5,2',4',5'-hexachlorobiphenyl (HCB). Interactions of these contaminants with major lipid classes (triacylglycerols and phospholipids) were examined by centrifuging aqueous whole organism homogenates of labeled animals into three discrete layers that were operationally defined as "buoyant-lipid," "particle" and "aqueous" fractions. The buoyant-lipid fraction contained most of the energy storing triacylglycerols, whereas the particle and aqueous fractions contained most of the membrane phospholipids. During 2 to 4 d experiments, unmodified BaP and HCB partitioned among the three fractions in proportion to the distribution of total-lipids in both species, but in M. relicta most of the BaP was biotransformed into polar metabolites that were selectively found in the aqueous and particle fractions. Apparently HCB was not substantially biotransformed in either species but took longer (ca. 2 d) to reach steady state among lipid pools in M. relicta than it did in P. hoyi (< 1 d). Although the contaminants did not always completely reach steady state in the organisms with respect to the external environments during these relatively short experiments, they appeared to reach steady state among lipid pools within the organisms.

GARDNER, W.S., M.A. QUIGLEY, G.L. FAHNENSTIEL, D. SCAVIA, and W. Frez. Pontoporeia hoyi--a direct trophic link between spring diatoms and fish in Lake Michigan. In Large Lakes: Ecological Structure and Function, M.M. Tilzer and C. Serruya (eds.). Springer-Verlag, New York, 632-644 (1990).

Several lines of evidence suggest that the Lake Michigan benthic amphipod, Pontoporeia hoyi (an important fish prey in large, temperate, low-nutrient lakes), may obtain a large portion of its annual energy directly from the spring diatom bloom: 1) Energetic considerations suggest that P. hoyi must assimilate a large fraction of energy from incoming organic material, but that summer input rates are not sufficient to support observed annual production of P. hoyi. 2) The weight-specific lipid content of P. hoyi at some locations in Lake Michigan doubles within a few weeks after the spring diatom bloom. 3) Lipids accumulate in P. hoyi primarily as the storage products, triglycerides. 4) P. hoyi feeds intermittently and can survive for months without food. 5) The dominant spring diatom in Lake Michigan, Melosira, is not significantly cropped by zooplankton and settles rapidly through the water column in the spring and early summer. 6) After the spring diatom bloom, the phytoplankton changes to a dominance of flagellates that are mostly eaten by pelagic zooplankton and therefore largely unavailable to benthic organisms. The ability of P. hoyi to rapidly accumulate and store energy from spring diatom blooms may help explain why this amphipod thrives in many temperate, oligotrophic/mesotrophic lakes. This apparently direct trophic linkage between spring diatoms and P. hoyi is energetically important because it involves a minimum of trophic energy loss between primary production and fish.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Annual Report for the Great Lakes Environmental Research Laboratory, FY 1988. Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 64 pp. (1990).

No abstract.

GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY. Annual Report for the Great Lakes Environmental Research Laboratory, FY 1989. Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 53 pp. (1990).

No abstract.

HARTMANN, H.C., and M.J. Donahue. The institutional morass: Constraints and opportunities for issue management. Proceedings, International and Transboundary Water Resources Issues, Toronto, Ontario, Canada, April 1-5, 1990. American Water Resources Association, 329-338 (1990).

A critical link exists between government policies and the institutional milieu which exists to fulfill those policies. Ostensibly, the large number of institutions which influence use of the Great Lakes leads to public confusion and a perception of institutional unresponsiveness. However, the current institutional setting is actually a rational response to several characteristics inherent to the Great Lakes system and government behavior; elimination of institutions simply to reduce the number of players is inappropriate. Rather, the exclusive and adversarial nature of traditional agency decision making processes appears to be a pivotal problem. Future planning must incorporate Alternative Dispute Resolution (ADR) processes, which seek to build consensus among the various interest groups (agencies included) that have some state in Great Lakes management decisions. For many contentious Great Lakes issues, ADR uniquely offers the potential for mutual learning by groups as their assumptions and perceptions are evaluated by other groups during facilitated policy dialogues, collaborative problem-solving, or negotiations.

HAWLEY, N., and J.E. ZYREN. Transparency calibrations for Lake St. Clair and Lake Michigan. Journal of Great Lakes Research 16(1):113-120 (1990).

Extensive measurements of water transparency using a Sea Tech transmissometer and total suspended solids (TSM) were made in the southern basin of Lake Michigan and in Lake St. Clair. The relationship between transparency and TSM in each lake can be expressed very well by a single equation. The similarity in the slopes of the lines for the two lakes suggested that the physical properties of the particles suspended in the water are very similar, while the large difference between the intercepts is due to the presence in Lake St. Clair of very fine material (particle diameter less that one micron) which is not present in Lake Michigan. Attempts to use the transparency measurements to identify different particle populations in Lake Michigan as a function of time, station, and sample depth were unsuccessful. Limited data from northern Lake Michigan, Lake Huron, and Lake Superior suggest that the material in Lake Huron is similar to that in the southern basin of Lake Michigan while the observations in northern Lake Michigan more closely resemble those from Lake Superior.

JOHENGEN, T.H., A.M. BEETON, and R.E. Holland. Saline Valley rural clean water project interim report on monitoring during 1989. Contract Report, Michigan Department of Agriculture, Washtenaw County Board of Commissioners, the Monroe County Board of Commissioners, the Washtenaw County Soil Conservation District, and the Monroe County Soil and Water Conservation District, 78 pp. (1990).

No abstract.

KEILTY, T.J. Note. Evidence for Alewife (Alosa pseudoharengus) predation on the European cladoceran Bythotrephes cederstroemi in northern Lake Michigan. Journal of Great Lakes Research 16(2):330-333 (1990).

Stomach contents of 10 alewife (Alosa pseudoharengus), 3 bloaters (Coregonus hoyi), 1 rainbow smelt (Osmerus mordax), 4 chinook salmon (Oncorhynchus tshawytscha), and 1 lake trout (Salvelinus namaycush) were examined for the presence of the European cladoceran, Bythotrephes cederstroemi. Fish were collected commercially (by gillnetters and sport charters) in July and August of 1988 in the North Manitou Island area of Lake Michigan when B. cederstroemi were abundant. The zooplankter was found in all alewife examined and its remains normally filled the entire stomach cavity. The only other evidence for fish predation on B. cederstroemi was found in the stomach from a 0.5 kg chinook salmon. A few caudal spine fragments were found in the stomach of one bloater yet because the stomach was full of the benthic amphipod, Pontoporeia hoyi, it was hypothesized that the fish acquired the remains from the sediments. Stomachs of other fish were either empty or did not contain B. cederstroemi. Although limited, these data are the first conclusive evidence that the economically important alewife prey upon the exotic B. cederstroemi in the open waters of the Great Lakes.

KEILTY, T.J., and P.F. LANDRUM. Population-specific toxicity responses by the freshwater oligochaete, Stylodrilus heringianus, in natural Lake Michigan sediments. Environmental Toxicology and Chemistry 9:1147-1154 (1990).

Sediment reworking rate, mortality and organism dry weight were measured for Stylodrilus heringianus in laboratory microcosms. The experiments were designed to identify potential population-specific response differences to mixed (stirred to obtain a more uniform particle size distribution over depth) and unmixed (passively settled) microcosm sediments. Lake Michigan sediments and worms were collected offshore Benton Harbor, Michigan and Grand Haven, Michigan. The mixed Benton Harbor sediments were toxic to S. heringianus collected from Grand Haven, whereas there were no significant differences in measured responses between mixed and unmixed sediment microcosms for Grand Haven-collected worms exposed to Grand Haven sediments or Benton Harbor-collected worms exposed to Benton Harbor sediments. Note that the mixing of sediments resulted in increased availability of contaminants sorbed to the fine sediment fraction. Because contaminant and oligochaete population density data suggest that Grand Haven sediments are less contaminated, the population-specific response suggests that S. heringianus may adapt to the low level long-term stressful conditions (chemical or otherwise). Results also suggest caution and consideration of the history of test organisms in the design and interpretation of toxicity tests.

LAIRD, G.A., and D. SCAVIA. Distribution of labile dissolved organic carbon in Lake Michigan. Limnology and Oceanography 35(2):443-447 (1990).

Bioassay-measured, labile dissolved organic carbon (LDOC) concentrations were compared in near-bottom and near-surface Lake Michigan water between April and October 1986. In five of seven experiments, the LDOC concentration was higher in near-bottom water. LDOC reached 40.2% of the total DOC pool in the near-bottom water in late May and 13.8% in the near-surface water in early July. Concentration in near-bottom water was highest during early stratification; concentration in surface water varied less but was highest in early July. The data suggested that an allochthonous source of labile organic C may be important.

LANDRUM, P.F., and J.A. ROBBINS. Bioavailability of sediment-associated contaminants to benthic invertebrates. In Sediments: Chemistry and Toxicity of In-Place Pollutants, R. Baudo, J. P. Giesy, and H. Muhtau (eds.). Lewis Publishers, Inc., Chelsea, MI, 237-263 (1990).

No abstract.

LANG, G.A., and T.D. FONTAINE. Modeling the fate and transport of organic contaminants in Lake St. Clair. Journal of Great Lakes Research 16(2):216-232 (1990).

Despite the rapid hydraulic turnover time of Lake St. Clair, inputs of organic contaminants to the lake are a cause for concern because of their potential long-term storage in the lake's surficial sediments. In order to understand and predict the transport and fate of organic contaminants in Lake St. Clair, a multisegment, contaminant mass balance model was developed. The model was calibrated and tested against four data sets that describe the behavior of the conservative chloride ion, and against two data sets that describe the fate and distribution of sediment-bound cesium-137. Model applications included simulations of octachlorostyrene (OCS) and polychlorinated biphenyl (PCB) dynamics in the lake. The model predicted that during 1971-83, 3.8 MT of OCS entered the lake, 2.8 MT were flushed from the system, 0.8 MT were lost due to biological degradation and volatilization, and 0.2 MT remained in the system. The model also predicted that during 1970-74, 3.4 MT of PCB entered the lake, 2.1 MT were flushed from the system, 2.2 MT were lost due to biological degradation and volatilization, and the system mass of PCB decreased from 1.9 to 1.0 MT.

LESHKEVICH, G.A., D.W. Deering, T.F. Eck, and S.P. Ahmad. Diurnal patterns of the bi-directional reflectance of fresh-water ice. Annals of Glaciology 14:153-157 (1990).

To improve the interpretation of surface cryospheric albedo from satellite sensor data, diurnal measurements of the spectral bi-directional reflectance of a commonly-found fresh-water ice type were made, from which hemispherical reflectance can be derived. The purpose of this study is to document its clear-sky, bidirectional reflectance characteristics in the visible (650-670 nm) and near-infrared (810-840 nm) region, assess the diurnal nature of the reflectance, and quantify the surface anisotropy. Bi-directional reflectances of the re-frozen slush ice measured show a spectral dependence and change significantly with solar zenith angle. Considerable variation occurs at each view angle and among view angles throughout the day. Although diurnal reflectance patterns were similar in both bands, the magnitudes varied greatly, being highest in the visible and lowest in the near-infrared region. With the exception of peak saturated (specular) values in the forward scatter direction, bi-directional reflectance was generally highest in the morning when the surface and the illumination were most diffuse in character. The exitance (pN) computed from nadir radiance (N) is compared to the measured hemispheric exitance (M). The pN/M ratio, an index of anisotropy, reveal an anisotropy that increases with increasing solar zenith angle and is more pronounced in the near-infrared region.

LINDNER, S.R. Sorption of volatile organic compounds and their mixtures on synthetic and natural soils. Ph.D. dissertation, Cornell University, Ithaca, NY, 230 pp. (1990).

Although sorption can have a profound influence on the fate of chlorinated hydrocarbon solvents and hydrocarbon fuels, the sorptive behavior of volatile organic compounds in unsaturated soils is relatively untested. A headspace analysis technique was used to measure the partitioning of 15 volatile organic compounds between the vapor phase and a synthetic soil sorbent made by coating aluminum oxide with Aldrich humic acid. The sorptive behavior of the 15 organic compounds was related to their physical/chemical properties to deduce sorbate properties which influence sorption from the vapor phase. since fuels and solvents are commonly introduced to the environment as component mixtures, a second objective was to study the behavior of sorbate mixtures. The effect of sorbent moisture content on observations was also considered.

PERNIE, G.L., D. SCAVIA, M.L. Pace, and H.J. CARRICK. Micrograzer impact and substrate limitation of bacterioplankton in Lake Michigan. Canadian Journal of Fisheries and Aquatic Sciences 47:1836-1841 (1990).

We estimated Lake Michigan epilimnetic heterotrophic bacterial loss rates, predator size, and substrate limitation in 1986 and 1987. The bacterial growth rates were always enhanced by organic substrate additions indicating that bacterial growth is limited, to some degree, by substrate availability. In this study we obtained loss rates and intrinsic growth rates each between 0.32 and 1.45 d-1. The grazers were predominantly picoplankton-size organisms, presumably heterotrophic flagellates. Using radiolabeled bacteria, only a small percentage (2-3%) of bacterial cells were incorporated in larger size fractions after 24 h. These results indicate that during our experiments heterotrophic bacteria were not a direct, significant, carbon source for t he upper trophic levels.

QUIGLEY, M.A., J.F. CAVALETTO, and W.S. GARDNER. Lipid composition related to size and maturity of the amphipod Pontoporiea hoyi. Journal of Great Lakes Research 15(4):601-610 (1989).

Micro-gravimetric determination of the lipid content of amphipods (Pontoporeia hoyi) obtained from a 45-m-deep Lake Michigan sampling site indicated that the mean lipid content of adult females was 30% on a non-lipid dry weight (NLDW) basis, and that juveniles and adult males contained 21 and 10% lipid (NLDW basis), respectively. Thin layer chromatography-flame ionization detection (TLC-FID) analyses revealed that lipids of females were composed primarily of triacylglycerols (81%), the principal energy storage lipid of amphipods. Lipids of juveniles were composed largely of triacylglycerols (41%) and phospholipids (44%). Adult male P. hoyi lipids consisted mostly of phospholipids (64%) and, secondarily, of triacylglycerols (12%). The relatively low triacylglycerol concentrations in males may be associated with the minimal requirements for energy stores to support metabolic needs during the male's brief (10 day) life span. By contrast, the high lipid content and marked abundance of triacylglycerols in adult females represents an important energy store supporting subsequent egg development, particularly since females appear to halt all feeding upon maturation. In juvenile P. hoyi, increased individual size (NLDW) was accompanied by increased lipid dry weight, implying that juveniles accumulate lipids during growth. Overall, the results demonstrated the importance of considering P. hoyi size, life stage, and sex when describing a population's lipid content or composition. This consideration is particularly critical when evaluating the role of P. hoyi in the transfer of energy and/or organic contaminants within the Great Lakes food web.

QUINN, F.H. Great Lakes water levels statistics and decision making. Proceedings, Great Lakes Water Level Forecasting and Statistics Symposium, Windsor, Ontario, Canada, May 17-18, 1990. Great Lakes Commission, Ann Arbor, MI, 205-209 (1990).

The Laurentian Great Lakes comprise one of the major water resources of North America. Planning for the future use and development around the Great Lakes requires a knowledge of past and potential future water level fluctuations. An excellent database of monthly water levels exists from 1860 to present with some additional data back to 1800. This data can be used to derive statistics to assist in decision making for varying planning horizons into the future. Statistical analysis of Great Lakes water levels is different from riverine systems because of long term persistence due to the large lakes surface areas and limited outlet capacity. The lake level variability and range are also dependent upon the climatic regime that is in effect. In addition, for about 12 years into the future, lake levels are conditionally dependent upon the current lake level. A major challenge is to analyze and present lake level statistics in such a way as to provide meaningful data for engineers, planners, water resource managers and others who are responsible for decisions based on future water level fluctuations.

QUINN, F.H., and C.E. SELLINGER. Note. Lake Michigan record levels of 1838, a present perspective. Journal of Great Lakes Research 16(1):133-138 (1990).

Record high lake levels for this century, set for all lakes but Ontario in 1985 and 1986, caused extensive economic losses and were a major concern of riparian interests. An analysis of early Lake Michigan-Huron water levels recorded at Milwaukee, Wisconsin, beginning in 1819 revealed an extremely high lake level regime peaking in 1838. To provide a valid comparison with recent data, the 19th century data were first adjusted to the International Great Lakes Datum of 1955 and corrected for differential isostatic rebound between Milwaukee and the outlet water level gage for Lake Michigan-Huron at Harbor Beach, Michigan. A comparison of the 1838 lake levels with the recent records indicates the former to be approximately 50 cm higher than the record set in 1986. A future recurrence of the climatic conditions causing the 1838 high lake levels would have a severe outcome for riparian interests throughout the Great Lakes region.

ROBBINS, J.A., A. Mudroch, and B.G. Oliver. Transport and storage of 137Cs and 210Pb in sediments of Lake St. Clair. Canadian Journal of Fisheries and Aquatic Sciences 47(3):572-587 (1990).

In 1985 cores were collected by diver from areas with fine-grained sediments in Lake St. Clair. Although the lake is shallow, rapidly flushed, and possesses only a thin layer of postglacial sediment (ca. 30 cm max.), 8% of the estimated 137Cs loading from atmospheric nuclear testing in the mid-1960s and 13% of the potential standing crop of excess 210Pb were retained. A sediment column transport model including eddy diffusive mixing, advection, and resuspension, acceptably described the vertical distribution of these radionuclides as well as stable lead and implied that such efficient retention may be of recent origin, occurring with the onset of net sedimentation about 100 yr ago. The model showed that, at selected sites, the history of lake loading by particle-associated contaminants can be reconstructed from sediment profiles. Horizontally averaged characteristics of the deposit indicate a surface mixed layer mass of 5 g cm-2 and tracer residence time of 3 yr in accord with residence times of surficial Hg, PCBs, and DDT. Trap-collected materials from two sites show markedly contrasting seasonal variations in 137Cs activity reflecting differing proportions of particles derived from inflow (ca 300 mBqlg-1) and resuspension (<30 mBq g-1).

Shabman, L., B. Smit, W. Shoots, L. Ludlow, K. O'Grady, H.C. HARTMANN, and C. Stewart. Living with the Lakes: Challenges and Opportunities, Annex C, Interests, Policies, and Decision Making: Prospects for Managing the Water levels Issue in the Great Lakes - St. Lawrence River Basin. International Joint Commission, Washington, DC, 153 pp. (1990).

No abstract.

STEHLY, G.R., and W.L. HAYTON. Effect of pH on the accumulation kinetics of pentachlorophenol in goldfish. Archives of Environmental Contamination and Toxicology 19:464-470 (1990).

The kinetics of accumulation of pentachlorophenol (PCP) at various pH values were investigated to explore how pH-dependent accumulation might influence PCP toxicity. Goldfish (Carassius auratus) were exposed to 5 mg PCP/L in a static system buffered with 7.5 uM bicine or N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (BES) at pH 7.0, 8.0, or 9.0. The amount of PCP in the fish, concentration of PCP in water, and the total amount of metabolites in the system were measured after exposure of fish from 1 to 96 h. Equations for these variables based on a two compartment pharmacokinetic model were fitted simultaneously to the data using NONLIN, which uses an iterative nonlinear least squares computer technique. Uptake clearance, metabolic clearance, and apparent volume of distribution of PCP decreased as pH increased. The decrease in PCP accumulation with increased pH was not due solely to a pH induced decrease in uptake. In addition, the distribution of PCP within the fish was altered by changes in the external pH. The pH-associated changes in distribution may have altered access of PCP to sites of metabolism, thereby altering the metabolic clearance. The pH-related changes in the pharmacokinetics of PCP resulted in a decrease in its bioconcentration factor with an increase in pH and account both for the decreased capacity of the fish to accumulate PCP and for its reduced LC50.

STEHLY, G.R., P.F. LANDRUM, M.G. Henry, and C. Klemm. Toxicokinetics of PAHs in Hexagenia. Environmental Toxicology and Chemistry 9:167-174 (1990).

The accumulation kinetics of two water-borne polycyclic aromatic hydrocarbons (PAHs), benzo(a)pyrene (BAP) and phenanthrene (PHE), were studied in the mayfly nymph (Hexagenia limbata). The uptake clearance decreased while the bioconcentration of BAP increased with an increase in the weight of the H. limbata nymph. The relationship between uptake clearance and bioconcentration for PHE was variable, and bioconcentration was greater for the heavier animals. Two kinetic models were used to evaluate the nymph weight on disposition of PAHs: (a) the amount-uptake clearance model, similar to models most frequently used in environmental toxicology; and (b) a clearance-volume model, similar to models used in clinical pharmacology. The two models gave similar predictive results but were different in a few cases. These differences in common parameter estimation probably resulted from methodologies used and high data variability rather than the models themselves, since they are mathematically equal. Some of the parameters are unique to each of the models defined and described. The clearance of oxygen from water is inversely and linearly related to the weight of the mayfly nymphs, but oxygen clearances were always much less than the uptake clearances of the PAHs. The high PAH uptake clearance compared to oxygen clearance implies a greater surface area or efficienty for PAH accumulation from water.

TARAPCHAK, S.J., and R.A. Moll. Phosphorus sources for phytoplankton and bacteria in Lake Michigan. Journal of Plankton Research 12(4):743-758 (1990).

Size-fractionation experiments on the uptake of phosphate (PO4) and recently excreted dissolved organic phosphorus (E-DOP) from phytoplankton suggest that algae and bacteria rely on different forms of phosphorus (P) in the epilimnion of P-limited Lake Michigan. Rate constants for PO4 uptake on 0-1 mm fractions generally were low relative to those measured in wholewater, suggesting that most of the uptake was by algae. Uptake of 33E-DOP in 0-1 mm fractions approximated uptake in wholewater, indicating uptake principally by bacteria. Concurrent experiments showed that (i) E-DOP and PO4 were taken up by different transport systems; (ii) bacteria have transport systems for E-DOP compounds; and (iii) cell-surface phosphatase-mediated PO4 supply to phytoplankton from E-DOP was negligible. Results suggest that pathways of PO4 and E-DOP flux in microplankton communities of P-limited large and small lakes may differ. The use of different sources of P by algae and bacteria in Lake Michigan supports the classical concept of algal-bacterial freshwater P cycling. These findings are consistent with a proposed hypothesis that, in large lakes with low allochthonous nutrient inputs, phytoplankton are P-limited and use PO4, while bacteria obtain P primarily from dissolved organic compounds and are limited by a nutrient other than P.

VANDERPLOEG, H.A., G.-A Paffenhofer, and J.R. LIEBIG. Concentration-variable interactions between calanoid copepods and particles of different food quality: Observations and hypotheses. In Behavioural Mechanisms of Food Selection, R.N. Hughes (ed.). Springer-Verlag, NATO ASI Series, Berlin Heidelberg, G20:595-613 (1990).

No abstract.

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