Search Results

Many living resources in the Chesapeake Bay estuary have deteriorated over the past 50 years. As a result, many governmental committees, task forces, and management plans have been established. Most of the recommendations for implementing a bay cleanup focus on reducing sediments and nutrient flow into the watershed. We emphasize...

We describe the nests and eggs of 7 species of colonial birds that nested on Malheur Lake in Malheur National Wildlife Refuge, Oregon, in 1980 and 1981. All nests were constructed over water in stands of hardstem bulrush (Scirpus acutus). We compared nest measurements among species and found...

Compared were concentrations of Al, Cd, Ca, Cu, Fe, Pb, Mg, Mn, Hg, Ni, P, and Zn in water, plants, and aquatic invertebrates of wetlands, ponds, and small lakes in Maryland and Maine. The accumulation of metals by aquatic plants and insects and the concentration of metals in water were...

Compared were concentrations of Al, Cd, Ca, Cu, Fe, Hg, Pb, Mg, Mn, Ni, P, and Zn in water, plants, and aquatic insects of three acidified (pH ∼ 5.0) and three nonacidified (pH ˜ 6.5) constructed wetlands. Concentrations of Zn in water and bur-reed (Sparganium americanum) were higher in acidified...

Seamount phosphorites have been recognized since the 1950s, but this is the first study to provide an in depth exploration of the origin and history of these widespread deposits. Representative samples from equatorial Pacific Cretaceous seamounts were analyzed for chemical, mineralogical, and stable isotope compositions. The phosphorites occur in a...

Salinity in the San Francisco Bay Estuary almost always experiences its yearly maximum during late summer, but climate variability produces marked interannual variations. The atmospheric circulation pattern impacts the estuary primarily through variations of runoff from rainfall and snowmelt from the Sierra Nevada and, secondarily, through variations in the near-surface...

The phenomenon of 'acid rain' is not new; it was recognized in the mid-1800s in industrialized Europe. In the 1960s a synthesis of information about acidification began in Europe, along with predictions of ecological effects. In the U.S. studies of acidification began in the 1920s. By the late 1970s research...

Data from several sources were collated and analyzed by correlation, regression, and principal components analysis to define surrrogate variables for use in the brook trout (Salvelinus fontinalis) habitat suitability index (HSI) model, and to evaluate the applicability of the model for assessing habitat in high elevation streams of the southern...

In 1992, the Vicksburg Field Research Station of the National Wetlands Research Center initiated research on the ecology of migratory birds within forests of the Mississippi Alluvial Valley (MAV). The MAV was historically a nearly contiguous bottomland hardwood forest, however, only remnants remain. These remnants are fragmented and often influenced...

Trail system planning and management require accurate assessments of existing trail resources and their condition. A standardized and efficient process for surveying, inventorying, and assessing trail systems was developed and applied in the Delaware Water Gap National Recreation Area. Two approaches employed were (1) a Trail System Inventory,...

The United States Fish and Wildlife Service coordinates several surveys that collect information on the population status of migratory birds in North America. The North American Breeding Bird Survey is the primary source of population information on nongame birds during the breeding season, and waterfowl surveys are conducted...

The Pliocene—Quaternary pattern of contourite deposits on the eastern Gulf of Cadiz continental slope results from an interaction between linear diapiric ridges that are perpendicular to slope contours and the Mediterranean undercurrent that has flowed northwestward parallel to the slope contours and down valleys between the ridges since the late...

Most continental flood basalts are enriched in incompatible elements and have high initial 87Sr/86Sr ratios and low ϵNd values. Many are depleted in Nb and Ta. The commonly-held view that these characteristics are inherited directly from a source in metasomatized lithospheric mantle is inconsistent with the following arguments: (1) thermomechanical modelling demonstrates that flood basalt...

Efflorescent salt crusts in Death Valley, California, were mapped by using Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and a recently developed least-squares spectral band-fitting algorithm. Eight different saline minerals were remotely identified, including three borates, hydroboracite, pinnoite, and rivadavite, that have not been previously reported from the Death Valley efflorescent...

The development of a large northeastern Atlantic shelf ostracod database has confirmed that an intrinsic relationship exists between watermass temperature and the spatial (latitudinal) distribution of benthonic shelf Ostracoda. A second Pliocene ostracod database, using assemblages from four boreholes in The Netherlands and a number of localities from the East...

No abstract available....

Mount Rainier is a young volcano whose slopes are undergoing rapid change by a variety of geologic processes, including debris flows. Debris flows are churning masses of water, rock and mud that travel rapidly down the volcano's steep, glacially carved valleys, leaving in their wake splintered trees, picnic sites buried...

Many landslides and debris flows have originated from Mount Rainier since the retreat of glaciers from Puget Sound about 10,000 years ago. The recurrent instability is due to several factors--height of the steep-sided volcanic cone, frequent volcanic activity, continuous weakening of rock by steam and hot, chemical-laden water, and exposure...

Public water supply in the Rockaway River valley depends almost entirely on ground water from wells in the valley-fill deposits. Ground-water withdrawals from these deposits in 1986 were about 9.1 million gallons per day. A steady-state ground-water flow model was developed to quantify the effects of ground-water withdrawals on water...

This report describes the results of a study by the U.S. Geological Survey, in cooperation with the West Virginia Geological and Economic Survey, to evaluate the distribution of fluoride in ground water of West Virginia. Fluoride is a natural chemical constituent in domestic and public water supplies in West Virginia....