Search Results

A year-long study of four western Montana streams (two impacted by mining and two “pristine”) evaluated surface water geochemical dynamics on various time scales (monthly, daily, and bi-hourly). Monthly changes were dominated by snowmelt and precipitation dynamics. On the daily scale, post-rain surges in some solute and particulate concentra tions...

The variation of baseline levels of uranium in soil and stream sediments over Europe is described, based on new data prepared by the Forum of European Geological Surveys (FOREGS). The samples have been collected and analysed according to the protocols established for the International Union of Geological Sciences/International Association of...

Seasonal variations in stream inorganic geochemistry are not well documented or understood. We sampled two mining-impacted and two relatively pristine streams in western Montana over a 12-month period, collecting samples every 4 weeks, with supplemental sampling (at least weekly) during spring runoff. We analyzed all samples for dissolved (operationally defined...

No abstract available....

We sampled the Blackfoot River (Montana) and its major tributaries from the headwaters of the basin to near its confluence with the Clark Fork River over the course of 5 days in August 1998. We measured streamflow, collected fine-grained (<63 μm) streambed sediment, and sampled the dissolved (operationally defined as...

This map was prepared as a collaborative effort with the Missouri Division of Geology and Land Survey, the Kansas Geological Survey, and the Nebraska Conservation and Survey Division. Map units and preliminary contacts between units were identified using stereoscopic pairs of high altitude, false color infrared, aerial photographs. Contacts were drawn on...

We used ultraclean sampling techniques to study the solute (operationally defined as <0.2 ?m) surface water geochemistry at five sites along the Upper Blackfoot River and four sites along the Landers Fork, some in more detail and more regularly than others. We collected samples also from Hogum Creek, a tributary to the Blackfoot,...

Geochemical maps of the conterminous United States have been prepared for seven major elements (Al, Ca, Fe, K, Mg, Na, and Ti) and 15 trace elements (As, Ba, Cr, Cu, Hg, Li, Mn, Ni, Pb, Se, Sr, V, Y, Zn, and Zr). The maps are based on an ultra low-density...

This geologic mapping and interpretation of the Pea Ridge iron mine, Missouri, is part of a cooperative effort between the U.S. Geological Survey (USGS) and the Missouri Department of Natural Resources, Division of Geology and Land Survey (DGLS), under the auspices of the USGS Midcontinent Strategic and Critical Minerals Project....

This dataset contains geochemical data for Alaska produced by the analytical laboratories of the Geologic Division of the U.S. Geological Survey (USGS). These data represent analyses of stream-sediment, heavy-mineral-concentrate (derived from stream sediment), soil, and organic material samples. Most of the data comes from mineral resource investigations conducted in the...

Hemlock ravines in Delaware Water Gap National Recreation Area (DEWA) are highly valued because of their distinctive aesthetic, recreational and ecological qualities. We conducted a comparative study designed to determine the potential long-term consequences to aquatic communities of the suspected transition from hemlock-dominated forests to mixed hardwood forests as a result of hemlock woolly adelgid (HWA; Adelges...

In previously reported work (Wright and others, 2000) we found that the very early time electromagnetic (VETEM) prototype system produced data from which high resolution images of a buried former foundry site at the Denver Federal Center were made. The soil covering the site is about 30 mS/m conductivity, and...

Salmonid whirling disease is caused by Myxobolus cerebralis, a metazoan parasite with a two host life cycle involving salmonid fish a an aquatic oligochaete, Tubifex tubifex (Wolf, Markiw and Hiltunen, 1986). Whirling disease has been reported in 22 U.S. states with the greatest losses occurring in the salmonid fisheries...

No abstract available....

Power analysis after study completion has been suggested to interpret study results. We present 3 methods of estimating power and discuss their limitations. We use simulation studies to show that estimated power can be biased, extremely variable, and severely bounded. We endorse the practice of computing power to detect a...

Electrogeochemical extraction methods are based on the migration of ions in an electric field. Ions present in soil moisture are transported by an applied current into fluids contained in special electrodes placed on the soil. The fluids are then collected and analyzed. Extractions are governed by Faraday's and Ohm's laws...

Accurate detection of Aeromonas salmonicida subsp. salmonicida (the cause of furunculosis disease) in covertly infected salmonids is difficult and is a cause of concern for those involved in fish health inspection and resource management programs. In this study, we examined populations of brook trout Salvelinus fontinalis, Atlantic salmon Salmo salar, and lake trout Salvelinus namaycush that previously sustained...

A revised annotated checklist for the chironomid midges (Diptera: Chironomidae) of the southeastern United States is presented that includes the states of Alabama, Florida, Georgia, North Carolina, South Carolina, and Tennessee. Much of the information concerns occurrence and habitat preference records based upon the authors' data, as well as published...

Because visibility bias can confound attempts to detect changes in abundance, we evaluated factors that affect visibility rate in aerial surveys of wintering waterfowl. We placed waterfowl decoys in 32 2- x 0.25-km strip transects in the Mississippi Alluvial Valley (MAV) during February 1990 and 1991 and observed the decoys...