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Despite concern over amphibian declines, few studies estimate absolute abundances because of logistic and economic constraints and previously poor estimator performance. Two estimation approaches recommended for amphibian studies are mark-recapture and depletion (or removal) sampling. We compared abundance estimation via various mark-recapture and depletion methods, using data from a three-year...

Storms are one of the most important controls on the cycle of erosion and accretion on beaches. Current meters placed in shoreface locations of Saco Bay and Wells Embayment, ME, recorded bottom currents during the winter months of 2000 and 2001, while teams of volunteers profiled the topography of nearby...

Improved interpretations of the strength of the San Andreas Fault near Parkfield, CA based on thermal data require quantification of processes causing significant scatter and uncertainty in existing heat flow data. These effects include topographic refraction, heat advection by topographically-driven groundwater flow, and uncertainty in thermal conductivity. Here, we re-evaluate...

The adsorption of uranyl on standard Georgia kaolinites (KGa-1 and KGa-1B) was studied as a function of pH (3–10), total U (1 and 10 μmol/l), and mass loading of clay (4 and 40 g/l). The uptake of uranyl in air-equilibrated systems increased with pH and reached...

Temperature anomalies associated with oil-producing structures in the US Midcontinent and similar cratonic areas probably can be used reliably as a passkey for petroleum exploration in mature areas, and thus the concept of hot anticlines could be a key to discovery. Analysis of accumulated data during the past several decades...

Lateral dispersion coefficients for two dispersants were determined for three sections of the Mississippi River below the confluence with the Ohio River. The dispersants were the specific conductance and an industrial organic compound (trimethyltriazinetrione). Three models based on the stream tube concept were used, and lateral dispersion coefficients computed from...

Over the past century, fire suppression and prevention have altered disturbance regimes across the Pacific Northwest, resulting in a significant divergence of historical and current conditions in forested habitats. To address this continuing trend in habitat changes and begin restoring historical patterns of disturbance, the Clearwater Basin Elk Habitat Initiative...

Currently 20-30 billion barrels of formation water are co-produced annually in the USA with conventional oil and natural gas. The large database on the geochemistry of this produced water shows salinities that vary widely from ~5,000 to >350,000 mg/L TDS. Chloride, Na and Ca are generally the dominant ions, and...

Manganese oxides are important scavengers of trace metals and other contaminants in the environment. The inclusion of Mn oxides in predictive models, however, has been difficult due to the lack of a comprehensive set of sorption reactions consistent with a given surface complexation...

For federal and state land management agencies, mineral resource appraisal has evolved from value-based to outcome-based procedures wherein the consequences of resource development are compared with those of other management options. Complex systems modeling is proposed as a general framework in which to build models that can evaluate outcomes. Three...

Herbivore foraging theories have been developed for and tested on herbivores across a range of sizes. Due to logistical constraints, however, little research has focused on foraging behavior of megaherbivores. Here we present a research approach that explores megaherbivore foraging behavior, and assesses the applicability of foraging theories developed on...

Imaging with acoustic and optical televiewers results in continuous and oriented 360° views of the borehole wall from which the character, relation, and orientation of lithologic and structural planar features can be defined for studies of fractured-rock aquifers. Fractures are more clearly defined under a wider range of conditions...

Multimetric biotic indices increasingly are used to complement physicochemical data in assessments of stream quality. We initiated development of multimetric indices, based on fish communities, to assess biotic integrity of streams in two physiographic regions of central Romania. Unlike previous efforts to develop such indices for European streams, our metrics...

Airborne spectral and light detection and ranging (lidar) sensors have been used to quantify biophysical characteristics of tropical forests. Lidar sensors have provided high-resolution data on forest height, canopy topography, volume, and gap size; and provided estimates on number of strata in a forest, successional status of forests, and above-ground...

Margin-parallel shortening of the Cascadia forearc is a consequence of oblique subduction of the Juan de Fuca plate beneath North America. Strike-slip, thrust, and oblique crustal faults beneath the densely populated Puget Lowland accommodate much of this north-south compression, resulting in large crustal earthquakes. To better understand this forearc deformation...

To help teachers and students investigate one of the world's most famous historical events using the geographic perspective and GIS tools and methods, the U.S. Geological Survey (USGS) created a set of educational lessons based on the RMS Titanic's April 1912 sailing. With these lessons, student researchers can learn about...

Geophysical tomograms are used increasingly as auxiliary data for geostatistical modeling of aquifer and reservoir properties. The correlation between tomographic estimates and hydrogeologic properties is commonly based on laboratory measurements, co-located measurements at boreholes, or petrophysical models. The inferred correlation is assumed uniform throughout the interwell region; however, tomographic resolution...

Effects of dissolved carbonate on arsenate [As(V)] reactivity and surface speciation at the hematite−water interface were studied as a function of pH and two different partial pressures of carbon dioxide gas [PCO2 = 10-3.5 atm and ∼0; CO2-free argon (Ar)] using adsorption kinetics, pseudo-equilibrium adsorption/titration experiments, extended X-ray absorption...

The San Bernardino basin is an area of Quaternary extension between the San Jacinto and San Andreas Fault zones in southern California. New gravity data are combined with aeromagnetic data to produce two- and three-dimensional models of the basin floor. These models are used to identify specific faults that have...

The abundance of white bass (Morone chrysops) in Lake Erie has declined in recent years, sparking interest in mechanisms influencing its recruitment. We evaluate two mechanisms affecting recruitment: diet and the potential for competition, and storage of lipid energy reserves and the relationship to overwinter survival. The fish in our...

We provide recommendations on the best practices for mist netting for the purposes of monitoring population parameters such as abundance and demography. Studies should be carefully thought out before nets are set up, to ensure that sampling design and estimated sample size will allow study objectives to be met. Station...

The USGS, in collaboration with other federal and state government agencies, industry, and academia, is conducting the National Geochemical Survey (NGS) to produce a body of geochemical data for the United States based primarily on stream sediments, analyzed using a consistent set of methods. These data will compose a...

Nevada's reliance on ground-water resources has increased because of increased development and surface-water resources being fully appropriated. The need to accurately quantify Nevada's water resources and water use is more critical than ever to meet future demands. Estimated ground-water pumpage, artificial and natural recharge, and interbasin flow can be used...

A new and unique vegetation greenness forecast (VGF) model was designed to predict future vegetation conditions to three months through the use of current and historical climate data and satellite imagery. The VGF model is implemented through a seasonality-adjusted autoregressive distributed-lag function, based on our finding that the normalized difference...

Researchers examining American black bear (Ursus americanus) denning behavior have relied primarily on den-site visitation and radiotelemetry to gather data. Repeated den-site visits are time-intensive and may disturb denning bears, possibly causing den abandonment, whereas radiotelemetry is sufficient only to provide gross data on den emergence. We used remote cameras...