Search Results

The distance fish can swim through zones of high-velocity flow is an important factor limiting the distribution and conservation of riverine and diadromous fishes. Often, these barriers are characterized by nonuniform flow conditions, and it is likely that fish will swim at varying speeds to traverse them. Existing models used...

Fifty-nine stream-water samples and 14 municipal wastewater treatment facility (WWTF) discharge samples in Johnson County, northeastern Kansas, were analyzed for 55 compounds collectively described as organic wastewater compounds (OWCs). Stream-water samples were collected upstream, in, and downstream from WWTF discharges in urban and rural areas during base-flow conditions. The effect...

EarthScope is a multidisciplinary geophysical investigation of the structure and deformation of the North American continent. Components include a transportable array of digital seismometers (USArray) that will image the continental crust and underlying mantle, and Global Positioning System (GPS) receivers and strainmeters (Plate Boundary Observatory, PBO) that will measure tectonic...

We modeled yellow-billed loon (Gavia adamsii) habitat preferences in a 23,500 km2 area of northern Alaska using intensive aerial surveys and landscape-scale habitat descriptors. Of the 757 lakes censused, yellow-billed loons occupied 15% and Pacific loons (G. pacifica) 42%. Lake area, depth, proportion of shoreline in aquatic vegetation,...

In studies designed to investigate the environmental exposure of fish in Lake Erie tributaries, a benthic fish, the brown bullhead (Ameiurus nebulosus), was collected from the industrially contaminated Detroit River, Ottawa River, Black River, Cuyahoga River-harbor and -upstream, Ashtabula River, Buffalo River, and Niagara River, and the non-industrialized Old Woman...

Results from a plume mapping study from November 2000 through February 2001 in the sand-and-gravel surficial aquifer at Dover Air Force Base, Delaware, were used to assess the occurrence and extent of chlorinated solvent mass loss by calculating mass fluxes across two transverse cross sections and by observing changes in...

Onsite wastewater treatment systems serve approximately 25% of the U.S. population. However, little is known regarding the occurrence and fate of organic wastewater contaminants (OWCs), including endocrine disrupting compounds, during onsite treatment. A range of OWCs including surfactant metabolites, steroids, stimulants, metal-chelating agents, disinfectants, antimicrobial agents, and...

Campanian through Maastrichtian mixed carbonate and siliciclastic sediments in a 422 m continuous core drilled at Kure Beach, NC provide a record of sea-level change. Based on lithology and stratigraphy, depositional sequences are defined, and calcareous nannofossil zones and 87Sr/86Sr ratios and corresponding ages using the LOWESS Table determined. Campanian...

Halides, particularly Br- and Cl-, have been used as indicators of potential sources of Na+ and Cl- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na+ and Cl- is a common occurrence in growing urban areas and adversely affects municipal and private water...

Walker Lake, a hydrologically closed, saline, and alkaline lake, is situated along the western margin of the Great Basin in Nevada of the western United States. Analyses of the magnetic susceptibility (??), total inorganic carbon (TIC), and oxygen isotopic composition (??18O) of carbonate sediments including ostracode shells (Limnocythere ceriotuberosa) from...

The virulence of the WSB-98 isolate of Piscirickettsia salmonis from white seabass Atractoscion nobilis was compared with that of the American Type Culture Collection type strain LF-89, which was originally isolated from coho salmon Oncorhynchus kisutch in Chile. In controlled laboratory challenges of juvenile coho salmon, the isolate from white...

Borehole radar tomography was used as part of a pilot study to monitor steam‐enhanced remediation of a fractured limestone contaminated with volatile organic compounds at the former Loring Air Force Base, Maine, USA. Radar tomography data were collected using 100‐MHz electric‐dipole antennae before and during steam injection to evaluate whether...

A field of giant sand waves, among the largest in the world, recently was mapped in high resolution for the first time during a multibeam survey in 2004 and 2005 through the strait of the Golden Gate at the mouth of San Francisco Bay in California (Figure la). This massive...

Recreational and commercial harvest of American shad Alosa sapidissima in the Virginia waters of the Chesapeake Bay and its tributaries has been prohibited since 1994. The Atlantic States Marine Fisheries Commission Shad and River Herring Management Plan requires that Virginia develop restoration targets for its shad populations, but estimates of...

We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased...

NASA’s Experimental Advanced Airborne Research Lidar (EAARL) is a raster-scanning, waveform-resolving, green-wavelength (532 nm) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor records the time history of the return waveform within a small footprint (20 cm diameter) for each laser pulse, enabling characterization of...

We determined how different hydroperiods affected leaf gas exchange characteristics of greenhouse-grown seedlings (2002) and saplings (2003) of the mangrove species Avicennia germinans (L.) Stearn., Laguncularia racemosa (L.) Gaertn. f., and Rhizophora mangle L. Hydroperiod treatments included no flooding (unflooded), intermittent flooding (intermittent), and permanent flooding (flooded). Plants in the intermittent treatment were measured under both...

Amphibian populations have declined worldwide. To pursue conservation efforts adequately, land managers need more information concerning amphibian habitat requirements. To address this need, we examined relationships between anurans and habitat characteristics of wetlands in the Lower Mississippi River Alluvial Valley (LMAV). We surveyed chorusing anurans in 31 wetlands in 2000...

Constant-flow permeability tests were conducted on core samples from Ocean Drilling Program Leg 201 from the eastern equatorial Pacific and the Peru margin. Eighteen whole-round core samples from Sites 1225, 1226, 1227, 1230, and 1231 were tested for vertical permeabilities. Sites 1225, 1226, and 1231 represent sediments of the open...

Fire alters the structure and composition of shrublands and affects habitat quality for the associated avifauna. Because shrubland ecosystems have been greatly reduced from their original extent in western North America and fire is increasingly being used to manage these landscapes, a better understanding of how fire affects the associated...

The estimation of aboveground biomass is important in the management of natural resources. Direct measurements by clipping, drying, and weighing of herbaceous vegetation are time-consuming and costly. Therefore, non-destructive methods for efficiently and accurately estimating biomass are of interest. We compared two non-destructive methods, visual obstruction and light penetration, for...

Spatial autocorrelation in species' distributions has been recognized as inflating the probability of a type I error in hypotheses tests, causing biases in variable selection, and violating the assumption of independence of error terms in models such as correlation or regression. However, it remains unclear whether these problems occur at...

Imaging spectroscopy has been successfully used to aid researchers in characterizing potential environmental impacts posed by acid-rock drainage, ore-processing dust on mangroves, and asbestos in serpentine mineral deposits and urban dust. Many of these applications synergistically combine field spectroscopy with remote sensing data, thus allowing more-precise data calibration, spectral analysis...

This paper updates a life-cycle net energy analysis and carbon dioxide emissions analysis of three Midwestern utility-scale wind systems. Both the Energy Payback Ratio (EPR) and CO2 analysis results provide useful data for policy discussions regarding an efficient and low-carbon energy mix. The EPR is the amount of electrical energy...

In this study, the presence, composition, and concentrations of organic wastewater contaminants (OWCs) were determined in solid materials produced during wastewater treatment. This study was undertaken to evaluate the potential of these solids, collectively referred to as biosolids, as a source of OWCs to soil and water...