Publications

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...

Information on the concentrations and spatial distributions of pesticides and their transformation products, or degradates, in the hydrologic system is essential for managing pesticide use in both agricultural and nonagricultural settings to protect water resources. This report examines the occurrence of selected herbicides and their degradates in ground water, primarily on the basis of...

Water-quality data from 17 surface-water monitoring sites were compiled for 1970 through 1995 and analyzed to determine historical waterquality conditions and possible trends in the Eastern Iowa Basins study unit as part of the U.S. Geological Survey's National Water-Quality Assessment Program. The Eastern Iowa Basins encompasses the Wapsipinicon, Cedar, Iowa, and Skunk River Basins and...

No abstract available.

Organochlorine and polycyclic aromatic hydrocarbon compounds are of concern in the Columbia River Basin because of their adverse effects on fish and wildlife. Because these compounds can have important biological consequences at concentrations well below the detection limits associated with conventional water-sampling techniques, we used semipermeable membrane devices (SPMDs) to sample...

No abstract available.

We created a model to study the process in which nutria (Myocastor coypus) feeding activities lead to erosion and loss of marsh area. This model ties together data on nutria population dynamics and feeding behavior from the literature with data from field studies on the phenology of Scirpus americanus and Spartina patens conducted in the Barataria Basin, Louisiana, USA in 1992. The...

We exposed albino and pigmented medakaOryzias latipes to simulated solar ultraviolet-B (UVB) radiation to determine if albino medaka were less tolerant of UVB radiation than medaka pigmented with melanin. There was no difference in the number of albino and pigmented medaka that died during the exposure period. Spectrophotometric analyses of the outer dorsal skin layers from albino and...

Water resources data for Iowa for the 1998 water year consists of records of stage, discharge, and water quality of streams; stage, and/or contents of lakes and reservoirs; ground water levels and water quality of ground-water wells. This report volume contains discharge records for 32 gaging stations; stage or contents for 2 lakes; water quality for 1 stream-gaging station, and sediment...

This document describes procedures used to collect information, tissues, and fluids for documenting the exposure of fish to environmental contaminants. For the procedures described here, fish are captured (preferably by electrofishing) and held alive until processing (generally

The 2,300-acre Lisbon Bottom Unit, located in central Missouri, became part of the Big Muddy National Fish and Wildlife Refuge (NFWR) after the Great Flood of 1993 devastated the Unit's farmland and network of levees. As a result, interdisciplinary studies were initiated through collaboration among various researches, universities, and State and Federal conservation agencies to...

An analysis of available hydrologic data was conducted to evaluate the effects on groundwater levels in the Missouri River alluvial aquifer caused by changes in Missouri River stage at selected sites in Fremont and Monona Counties in western Iowa. Daily mean ground-water levels and river stage measured during November 1995- September 1996, simulated daily mean river stage for November...