An assessment of the sources of error in estimations of bulk sedimentary pigment concentrations and its implications for trophic status assessment

Rates of leaf litter processing and densities of macroinvertebrates in leaf packs were compared at two sites that differed in catchment logging history. The processing rate of leaves of sugar maple (Acer saccharum Marsh.) was significantly faster in a stream draining a catchment that had been logged about 20 years ago than in one that had been undisturbed for 80 years. The faster processing rate was accompanied by significantly higher leaf pack densities of total macroinvertebrates, shredders, and collector-gatherers. The higher densities of leaf pack macroinvertebrates were apparently a result of differences in tree species between the two catchments. These differences resulted in greater inputs of fast-decomposing leaf litter to the stream draining the disturbed catchment and in smaller amounts of leaf litter remaining in the stream draining the disturbed catchment by spring when this study was conducted. The Unit is jointly sponsored by the West Virginia Department of Natural Resources, West Virginia University, the U.S. Fish and Wildlife Service, and the Wildlife Management Institute. The Unit is jointly sponsored by the West Virginia Department of Natural Resources, West Virginia University, the U.S. Fish and Wildlife Service, and the Wildlife Management Institute.     

Improved methods for detecting enteric viruses in oysters.

New and improved methods for concentrating enteroviruses, reoviruses, and adenoviruses from oysters have been developed and evaluated. Viruses are efficiently adsorbed to homogenized oyster meat by adjusting the homogenate to pH 5.0 and a conductivity of less than or equal to 2,000 mg of NaCl per liter. After low-speed centrifugation, the virus-free supernatant is discarded and the viruses are eluted from the sedimented oyster solids with pH 7.5 glycine-NaCl having a conductivity of 8,000 mg of NaCl per liter. The oyster solids are removed by low-speed centrifugation and filtration, and the viruses in the filtered supernatant are concentrated to a small volume by either ultrafiltration or acid precipitation at pH 4.5. The concentrate is treated with antibiotics and inoculated into cell cultures for virus isolation and quantitation. When these methods were tested with oysters experimentally contaminated with polioviruses, reoviruses, and adenoviruses, recovery efficiencies averaged about 46%. With the exception of virus assay and quantitation, these methods are simple and inexpensive enough to be done in typical shellfish microbiology laboratories.     

The three-spined stickleback as an environmental sentinel: effects of stressors on whole-body physiological indices

Indicators of a generalized stress response (changes in cortisol, glucose, RNA: DNA ratio and total protein) when measured in whole-body preparations of individual three-spined sticklebacks Gasterosteus aculeatus displayed significant alterations in response to acute (hours) and chronic (days) disturbances and food withdrawal. In addition, changes in alkali-labile phosphorous, a specific biomarker of exposure to oestrogenic contaminants, could be detected in whole-body preparations of oestrogen-exposed three-spined sticklebacks confirming that the measurement of biomarkers normally assessed in a specific tissue can be equally possible in whole fish.