Skip to main content
U.S. flag

An official website of the United States government

Articles

Browse more than 65,000 articles authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.

Filter Total Items: 77848

Luminescence ages and new interpretations of the timing and deposition of Quaternary sediments at Natural Trap Cave, Wyoming Luminescence ages and new interpretations of the timing and deposition of Quaternary sediments at Natural Trap Cave, Wyoming

Natural Trap Cave, located in the Big Horn Mountains of north-central Wyoming, has a history of trapping and preserving a range of North American fauna that plummeted into the deep vertical entrance. These animal remains were buried and preserved within sediments of the main chamber and, in turn, have helped elucidate the procession of faunal dynamics during the latest glacial cycle. The...
Authors
Shannon A. Mahan, John R. Wood, Dave M Lovelace, Juan Laden, Jenny McGuire, Julie Meachen

Natural and anthropogenic influences on benthic cyanobacteria in streams of the northeastern United States Natural and anthropogenic influences on benthic cyanobacteria in streams of the northeastern United States

Benthic cyanobacteria are widespread in streams and rivers and have the potential to release toxins. In large numbers, these microorganisms and their toxins present a risk to human health. Cyanobacterial abundance in stream biofilms is typically related to single or a limited set of environmental factors, mainly light availability, water temperature, and nutrient concentrations. However...
Authors
Nicholas O. Schulte, Daren M. Carlisle, Sarah A. Spaulding

Limited land base and competing land uses force societal tradeoffs when siting energy development Limited land base and competing land uses force societal tradeoffs when siting energy development

As human populations grow, decisions regarding use of the world's finite land base become increasingly complex. We adopted a land use–conflict scenario involving renewable energy to illustrate one potential cause of these conflicts and resulting tradeoff decisions. Renewable energy industries wishing to expand operations in the United States are limited by multijurisdictional regulations...
Authors
Jill A. Shaffer, Neal D. Niemuth, Charles R. Loesch, Clayton E. Derby, Aaron T. Pearse, Kevin W. Barnes, Terry L. Shaffer, Adam J. Ryba

Comparison of methods for estimating density and population trends for low-density Asian bears Comparison of methods for estimating density and population trends for low-density Asian bears

Populations of bears in Asia are vulnerable to extinction and effective monitoring is critical to measure and direct conservation efforts. Population abundance (local density) or growth (λ) are the most sensitive metrics to change. We discuss the value in implementing spatially explicit capture-recapture (SCR), the current gold standard for density estimation, and open population SCR...
Authors
Dana J. Morin, John Boulanger, Richard Bischof, David C. Lee, Dusit Ngoprasert, Angela K. Fuller, Bruce McLellan, Robert Steinmetz, Sandeep Sharma, Dave Garshelis, Arjun M. Gopalaswamy, Muhammad Ali Nawaz, Ullas Karanth

Drivers of flight performance of California Condors (Gymnogyps californianus) Drivers of flight performance of California Condors (Gymnogyps californianus)

Flight behavior of soaring birds depends on a complex array of physiological, social, demographic, and environmental factors. California Condors (Gymnogyps californianus) rely on thermal and orographic updrafts to subsidize extended bouts of soaring flight, and their soaring flight performance is expected to vary in response to environmental variation and, potentially, with experience...
Authors
Sophie R. Bonner, Sharon A. Poessel, Joseph C. Brandt, Molly T. Astell, James R. Belthoff, Todd E. Katzner

Water chemistry, exposure routes and metal forms determine the bioaccumulation dynamics of silver (ionic and nanoparticulate) in Daphnia magna Water chemistry, exposure routes and metal forms determine the bioaccumulation dynamics of silver (ionic and nanoparticulate) in Daphnia magna

Treatment wetlands utilize various physical and biological processes to reduce levels of organic contaminants, metals, bacteria, and suspended solids. Silver nanoparticles (AgNPs) are one type of contaminant that can enter treatment wetlands and impact the overall treatment efficacy. Grazing by filter-feeding zooplankton, such as Daphnia magna, is critical to treatment wetland...
Authors
Emma Lesser, Fatima Noor Sheikh, Mithun Sikder, Marie Noele Croteau, Natasha Franklin, Mohammed Baalousha, Niveen S. Ismail

Synthetic aperture radar volcanic flow maps (SAR VFMs): A simple method for rapid identification and mapping of volcanic mass flows Synthetic aperture radar volcanic flow maps (SAR VFMs): A simple method for rapid identification and mapping of volcanic mass flows

Volcanic mass flows, including lava, pyroclastic density currents, and lahars, account for the bulk of fatalities and infrastructure damage caused by volcanic eruptions. Mapping these flows soon after their emplacement is vital to understanding their impact and to forecasting the likely behavior of potential future flows. Synthetic aperture radar (SAR) can provide useful information...
Authors
Michael Poland

Rotenone use and subsequent prey loss lowers Osprey fledging rates via brood reduction Rotenone use and subsequent prey loss lowers Osprey fledging rates via brood reduction

Fisheries managers used the fish toxicant rotenone to eradicate an undesirable brown bullhead (Ameiurus nebulosus) population and all other fish species at Hyatt Reservoir, Oregon, on 12 October 1989. This 4-yr study (1988–1990, 1992) compared effects of that rotenone project on Ospreys (Pandion haliaetus) nesting at Hyatt Reservoir and nearby Howard Prairie Reservoir (untreated...
Authors
Charles J. Henny, James L Kaiser

Selecting the optimal fine-scale historical climate data for assessing current and future hydrological conditions Selecting the optimal fine-scale historical climate data for assessing current and future hydrological conditions

High-resolution historical climate grids are readily available and frequently used as inputs for a wide range of regional management and risk assessments, including water supply, ecological processes, and as baseline for climate change impact studies that compare them to future projected conditions. Because historical gridded climates are produced using various methods, their portrayal...
Authors
Michelle A. Stern, Lorraine E. Flint, Alan L. Flint, Ryan M Boynton, Joseph A E Stewart, Jessica W Wright, James H. Thorne

State of stress in areas of active unconventional oil and gas development in North America State of stress in areas of active unconventional oil and gas development in North America

In this paper, we present comprehensive data on stress orientation and relative magnitude in areas throughout North America where unconventional oil and gas are currently being developed. We find excellent agreement between maximum horizontal principal stress (SHmax) orientations over a wide range of depths, using multiple methods. In all basins studied, we observed coherent stress...
Authors
Jens-Erik Lundstern, Mark D. Zoback

Simple relationships between residence time and annual nutrient retention, export, and loading for estuaries Simple relationships between residence time and annual nutrient retention, export, and loading for estuaries

Simple mathematical models are derived from mass balances for water and transported substance to provide insight into the relationships between import, export, transport, and internal removal for nonconservative substances in an estuary. Extending previous work, our models explicitly include water and substance inputs from the ocean and are expressed in terms of timescales (i.e., mean...
Authors
Jian Shen, Jiabi Du, Lisa Lucas

Biomass allocation of tidal freshwater marsh species in response to natural and manipulated hydroperiod in coastal deltaic floodplains Biomass allocation of tidal freshwater marsh species in response to natural and manipulated hydroperiod in coastal deltaic floodplains

Deltaic floodplains are highly vulnerable to relative sea level rise (RSLR) depending on the sediment supply from river channels that provides elevation capital as adaptation mechanism. In river channels where levees have restricted sediment supply to coastal deltaic floodplains, river sediment diversions have been proposed as a restoration strategy to increase elevation allowing for...
Authors
Andre S. Rovai, Robert R. Twilley, Alexandra Christiensen, Annabeth McCall, Daniel J. Jensen, Gregg Snedden, James T. Morris, John A. Cavell
Was this page helpful?