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Filter Total Items: 3374

Important observations and parameters for a salt water intrusion model

Sensitivity analysis with a density-dependent ground water flow simulator can provide insight and understanding of salt water intrusion calibration problems far beyond what is possible through intuitive analysis alone. Five simple experimental simulations presented here demonstrate this point. Results show that dispersivity is a very important parameter for reproducing a steady-state distribution
Authors
W.B. Shoemaker

Measuring mercury and other elemental components in tree rings

There has been considerable interest in measuring heavy metal pollution, such as mercury, using tree ring analysis. Since 1970, this method has provided a historical snapshot of pollutant concentrations near hazardous waste sites. Traditional methods of analysis have long been used with heavy metal pollutants such as mercury. These methods, such as atomic fluorescence and laser ablation, are somet
Authors
C. Gillan, W.A. Hollerman, T.W. Doyle, T.E. Lewis

Latitudinal variation in carbon storage can help predict changes in swamps affected by global warming

Plants may offer our best hope of removing greenhouse gases (gases that contribute to global warming) emitted to the atmosphere from the burning of fossil fuels. At the same time, global warming could change environments so that natural plant communities will either need to shift into cooler climate zones, or become extirpated (Prasad and Iverson, 1999; Crumpacker and others, 2001; Davis and Shaw,
Authors
Beth A. Middleton, Karen McKee

Purple loosestrife volunteers

Purple loosestrife (Lythrum salicaria) is a perennial plant native to Eurasia where it grows along streams, rivers, and wet seepage areas (fig. 1). Seeds were inadvertently brought to North American territories in the ballast water of ships. Purple loosestrife was also intentionally planted throughout North America for its ornamental flowers but has since escaped cultivation to spread to wetlands.
Authors
Beth A. Middleton

Cattle grazing and its long-term effects on sedge meadows

Most people think that wetlands are temporary, that they fill in by natural processes, and eventually become dry land. Some of these outdated ideas have come from the way that this subject has been covered in introductory textbooks in schools (Gibson, 1996). From these texts, we learned incorrectly that over time a lake fills with sediment or organic matter to become a wetland, which dries out to
Authors
Beth Middleton

Coefficients of productivity for Yellowstone's grizzly bear habitat

This report describes methods for calculating coefficients used to depict habitat productivity for grizzly bears in the Yellowstone ecosystem. Calculations based on these coefficients are used in the Yellowstone Grizzly Bear Cumulative Effects Model to map the distribution of habitat productivity and account for the impacts of human facilities. The coefficients of habitat productivity incorporate
Authors
David John Mattson, Kim Barber, Ralene Maw, Roy Renkin

Standing crop and aboveground biomass partitioning of a dwarf mangrove forest in Taylor River Slough, Florida

The structure and standing crop biomass of a dwarf mangrove forest, located in the salinity transition zone ofTaylor River Slough in the Everglades National Park, were studied. Although the four mangrove species reported for Florida occurred at the study site, dwarf Rhizophora mangle trees dominated the forest. The structural characteristics of the mangrove forest were relatively simple: tree heig
Authors
C. Coronado-Molina, J.W. Day, E. Reyes, B.C. Perez

Mechanisms for dominance in an early successional old field by the invasive non-native Lespedeza cuneata (Dum. Cours.) G. Don

Researchers studying invasive plants often concentrate their efforts on predictive models thought to allow invasive plants to dominate native landscapes. However, if an invasive is already well established then experimental research is necessary to provide the information necessary to effectively manage the species. Prescribing appropriate management strategies without prior experimental research
Authors
A.L. Brandon, D.J. Gibson, B.A. Middleton

Flow cytometric analysis of crayfish haemocytes activated by lipopolysaccharides

Lipopolysaccharides (LPS) from Gram-negative bacteria are strong stimulators of white river crayfish, Procambarus zonangulus, haemocytes in vitro. Following haemocyte treatment with LPS and with LPS from rough mutant R5 (LPS Rc) from Salmonella minnesota, flow cytometric analysis revealed a conspicuous and reproducible decrease in cell size as compared to control haemocytes. These LPS molecules al
Authors
W. Cardenas, J.R. Dankert, J.A. Jenkins

Dynamic consequences of allochthonous nutrient input into freshwater systems

Abstract not supplied at this time
Authors
D.L. DeAngelis, P. J. Mulholland

Cichlidae

No abstract available.
Authors
P. J. Schofield, A. B. Powell