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A radioisotope method for measurement of bacteria respiratory reduction of selenate to elemental selenium in aquatic sediments was devised. Sediments were labeled with [75Se]selenate, incubated, and washed, and 75Se0(s) was determined as counts remaining in the sediments. Core profiles of selenate reduction, sulfate reduction, and denitrification were made simultaneously in...

Shallow soil slips, earth and debris slides appear to be a primary mechanism of hillslope denudation in the rainforest of eastern Puerto Rico. Annual rainfall in excess of 4,000 mm, and thick sequences (up to 20 m) of residual soils (saprolite) combine to produce these landslides. Shear strength testing and...

Soil moisture conditions are not well documented in steep, tropical landslide-prone terrain. In the 11,330 ha Caribbean National Forest (CNF) in northeastern Puerto Rico more than 170 landslides that occurred from one to approximately 60 years ago have been mapped. Most of these landslides are shallow, with failure depths of...

A differentially connected array of proton magnetometers operated within the epicentral region of the October 18, 1989, ML 7.1 Loma Prieta earthquake for 12 years from 1974 to 1986. The closest magnetometer station was located 7.3 km from the epicenter of the earthquake and within 3 km of the site where...

Quantitative estimates of metamorphic fluid speciation, stable isotopic analyses, and studies of fluid inclusions all document the local complexity of fluids in the deep crustal rocks exposed in the Adirondack Mountains, NY. Estimates of the activity of H2O in the granulite facies are substantially lower than in the amphibolite...

The organic component of the vapor phase of a porous medium contaminated by an immiscible organic liquid can be significant enough to violate the condition of a dilute species diffusing in a bulk phase assumed by Fick's law. The Stefan-Maxwell equations provide a more comprehensive model for quantifying steady state...

Lake Ontario's water levels have been regulated since 1959, after the completion of the St. Lawrence River navigation and hydropower development project. The plan used to guide the regulation (1958-D) has been in effect since 1963 (Bryce, 1982). The purpose of the regulation was to prevent extreme...

The water balance describes climate as it is sensed by plants, as the interaction of energy and water in the environment. Discriminant analysis showed that the distribution of North American plant formations was more highly correlated with the water balance (actual evapotranspiration and deficit) than with the more traditional measures...

Four measures of behavior-spontaneous swimming activity, swimming capacity, feeding behavior, and vulnerability to predation-were assessed as indicators of sublethal toxicity in rainbow trout (Oncorhynchus mykiss) in 96-hr exposures to sublethal concentrations of six agricultural chemicals: carbaryl, chlordane, dimethylamine salt of 2,4-dichlorophenoxyacetic acid (2,4-DMA), tributyl phosphorotrithioate (DBF 1), methyl...

Energy development of all types continues to grow in the Rocky Mountain Region of the western United States. Federal resource managers increasingly need to balance energy demands, their effects on the natural and human landscape, and public perceptions towards these issues. The Western Energy Citation Clearinghouse (WECC v.1.0), part of...

I developed methods of estimating confidence intervals for the federal waterfowl harvest surveys conducted by the U.S. Fish and Wildlife Service (USFWS). I estimated flyway harvest confidence intervals for mallards (Anas platyrhynchos) (95% CI are ± 8% of the estimate). Canada geese (Branta canadensis) (±11%), black ducks (Anas rubripes) (±16%),...

We evaluated 3 techniques (air jet, flat skin, grab sample) to assess molt in dead waterfowl (green- winged teal [Anas crecca] and king eider [Somateria spectabilis]). The air jet technique was fast and required no specimen preparation. The flat skin technique required lengthy preparation time after which molt was assessed...

Three experiments were performed on natural slopes to investigate variations of soil pore-water pressure during induced slope failure. Two sites in the Wasatch Range, Utah, and one site in the San Dimas Experimental Forest of southern California were forced to fail by artificial subsurface irrigation. The sites were instrumented with...

We use magnetostratigraphy and Sr-isotope stratigraphy to improve stratigraphic control for the Eocene to Oligocene of the New Jersey coastal plain (ACGS4 borehole). Magnetostratigraphy in many cases is complicated in outcrop sections of shallow-water (<200 m paleodepth) sediments by low remanence and weathering; we minimize these problems by analyzing large...

Bedded quartz cherts that contain recognizable diatoms are rare in the geologic record and are described here for the first time. The Eocene Andrew Lake Formation on Adak Island, Alaska consists of about 800 m of sedimentary and volcanogenic rocks. Quartz cherts containing diatoms occur in the upper part of...

In this paper stability and error analyses are discussed for some finite difference methods when applied to the one-dimensional shallow-water equations. Two finite difference formulations, which are based on a combined Eulerian-Lagrangian approach, are discussed. In the first part of this paper the results of numerical analyses for an explicit...

Chemical and biological interactions involving arsenic (As) and phosphorus (P) appear to affect significantly As transport and distribution in Whitewood Creek, South Dakota. Data (first‐order uptake rate constants, standing crop, and accumulation factors) that can be used to predict As transport have been determined using algae collected in the creek...

Two distinct hydrogeochemical regimes currently dominate the Peruvian continental margin. One, in shallower water (150-450 m) shelf to upper-slope regions, is characterized by interstitial waters with strong positive chloride gradients with depth. The maximum measured value of 1043 mM chloride at Site 680 at ITS corresponds to a degree of...

Hydrocarbon gases (methane, ethane, propane, isobutane, «-butane, ethene, and propene) are present in Tertiary and Quaternary shelf, upper-slope, and lower-slope deposits of the Peruvian continental margin. Methane dominates the composition of the hydrocarbon gas at all 10 sites examined during Ocean Drilling Program (ODP) Leg 112. Generation of methane is...

Gas hydrates were recovered during coring by Ocean Drilling Program (ODP) Leg 112 at Sites 685 and 688 on the Peruvian outer continental margin at latitudes of 9° and 11.5°S, where water depths are 5070 and 3820 m, respectively. In addition, nearby Sites 682 and 683 yielded compelling evidence that...

Since its introduction, Ceriodaphnia dubia, a small planktonic daphnid, has been widely used for biomonitoring point source discharges. This species was also used to determine nonpoint sources of metals and related contaminants in three trout streams in the west where mining activities have been widespread. Along Chalk Creek, Colo., specific...

Efforts to relate shallow ground-water quality to the land use near a well lead to several statistical difficulties. These include potential uncertainty in land-use categorical data due to misclassification, data closure, distributional skewing, and spatial autocorrelation. Methods of addressing these problems are, respectively, the establishment of limits on minimum buffer...

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