Publications

No abstract available.

A comprehensive set of soil characteristics were examined to determine the effect of soil on the transport of agrichemicals to ground water. This paper examines the relation of local soil characteristics to concentrations and occurrence of nitrate, atrazine (2-chloro-4 ethylamino-6-isopropylamino-s-trazine), and atrazine residue [atrazine + deethylatrazine (2-amino-4-chloro-6...

No abstract available.

No abstract available.

Ground-water samples were collected from 33 domestic wells to assess the water quality of the eastern part of the Silurian-Devonian and Upper Carbonate aquifers in the Eastern Iowa Basins National Water-Quality Assessment Program study unit. Samples were collected during June and July 1996 and analyzed for major ions, nutrients, pesticides and pesticide metabolites, volatile organic...

Ideally, general ecological relationships may be used to predict responses of natural communities to environmental change, but few attempts have been made to determine the reliability of predictions based on descriptive data. Using a previously published structural equation model (SEM) of descriptive data from a coastal marsh landscape, we compared these predictions against observed...

Town Lake, the last in the chain of Highland Lakes on the Colorado River, runs through the center of Austin, Texas. On any given day, grebes and coots dot the water, rowers skim alongside, and the sparkle of the sun on the water can be admired from the adjacent hike and bike path and from the windows of nearby office buildings. During the summer months, crowds gather along the shores of...

The South Florida Ecosystem Restoration Program is an intergovernmental effort to reestablish and maintain the ecosystems of south Florida. One element of the restoration effort is the development of a firm scientific basis for resource decision making. The U.S. Geological Survey (USGS) is one of the agencies that provides scientific information as part of the South Florida Ecosystem...

Ecosystems are communities of organisms, often including humans, and the associated physical and chemical environments in which they live. Ecosystems are a complex natural resource that need to be understood, carefully managed, and prudently conserved. Human modification of the environment, such as changing water drainage patterns and introducing pollutants (such as mercury) and...

Previous research on the distribution of Neosho madtoms, which are Federally-listed as threatened, indicated a positive relationship between density of Neosho madtoms and cumulative density of other riffle-dwelling benthic fishes. This suggested that interspecific competition was not limiting Neosho madtom populations. We provide further evidence that interspecific competition is not...

A method is described for preparing formulated sediments for use intoxicity testing. Ingredients used to prepare formulated sediments included commercially available silt, clay, sand, humic acid, dolomite, and α-cellulose (as a source of organic carbon). α-Cellulose was selected as the source of organic carbon because it is commercially available, consistent from batch to batch, and low...

No abstract available.