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: 78958

Relation between road-salt application and increasing radium concentrations in a low-pH aquifer, southern New Jersey Relation between road-salt application and increasing radium concentrations in a low-pH aquifer, southern New Jersey

The Kirkwood–Cohansey aquifer in southern New Jersey is an important source of drinking-water supplies, but the availability of the resource is limited in some areas by high concentrations of radium, a potential carcinogen at elevated concentrations. Radium (226Ra plus 228Ra) concentrations from a network of 25 drinking-water wells showed a statistically significant increase over a...
Authors
Bruce D. Lindsey, Charles A. Cravotta, Zoltan Szabo, Kenneth Belitz, Paul E. Stackelberg

Growing as slow as a turtle: Unexpected maturational differences in a small, long-lived species Growing as slow as a turtle: Unexpected maturational differences in a small, long-lived species

Turtle body size is associated with demographic and other traits like mating success, reproductive output, maturity, and survival. As such, growth analyses are valuable for testing life history theory, demographic modeling, and conservation planning. Two important but unsettled research areas relate to growth after maturity and growth rate variation. If individuals exhibit indeterminate...
Authors
Devin Edmonds, Michael J. Dreslik, Jeffrey E. Lovich, Thomas P. Wilson, Carl H. Ernst

Climatic controls on soil carbon accumulation and loss in a dryland ecosystems Climatic controls on soil carbon accumulation and loss in a dryland ecosystems

Arid and semiarid ecosystems drive year-to-year variability in the strength of the terrestrial carbon (C) sink, yet there is uncertainty about how soil C gains and losses contribute to this variation. To address this knowledge gap, we embedded C-depleted soil mesocosms, containing litter or biocrust C inputs, within an in situ dryland ecosystem warming experiment. Over the course of one...
Authors
Bonnie G. Waring, Kenneth R Smith, Edmund E. Grote, Armin J. Howell, Robin H. Reibold, Colin L Tucker, Sasha C. Reed

A science agenda to inform natural resource management decisions in an era of ecological transformation A science agenda to inform natural resource management decisions in an era of ecological transformation

Earth is experiencing widespread ecological transformation in terrestrial, freshwater, and marine ecosystems that is attributable to directional environmental changes, especially intensifying climate change. To better steward ecosystems facing unprecedented and lasting change, a new management paradigm is forming, supported by a decision-oriented framework that presents three distinct...
Authors
Shelley Crausbay, Helen R. Sofaer, Amanda E. Cravens, Brian C. Chaffin, Katherine R. Clifford, John E. Gross, Corrine N. Knapp, David Lawrence, Dawn Magness, Abraham J. Miller-Rushing, Gregor W. Schuurman, Camille S. Stevens-Rumann

RAD adaptive management for transforming ecosystems RAD adaptive management for transforming ecosystems

Intensifying global change is propelling many ecosystems toward irreversible transformations. Natural resource managers face the complex task of conserving these important resources under unprecedented conditions and expanding uncertainty. As once familiar ecological conditions disappear, traditional management approaches that assume the future will reflect the past are becoming...
Authors
Abigail J. Lynch, Laura M. Thompson, John M. Morton, Erik A. Beever, Michael Clifford, Douglas Limpinsel, Robert T. Magill, Dawn R. Magness, Tracy A. Melvin, Robert A. Newman, Mark T. Porath, Frank J. Rahel, Joel H. Reynolds, Gregor W. Schuurman, Suresh Sethi, Jennifer L. Wilkening

Responding to ecological transformation: Mental models, external constraints, and manager decision-making Responding to ecological transformation: Mental models, external constraints, and manager decision-making

Ecological transformation creates many challenges for public natural resource management and requires managers to grapple with new relationships to change and new ways to manage it. In the context of unfamiliar trajectories of ecological change, a manager can resist, accept, or direct change, choices that make up the resist-accept-direct (RAD) framework. In this article, we provide a...
Authors
Katherine R. Clifford, Amanda E. Cravens, Corrine N. Knapp

Accounting for fine-scale forest structure is necessary to model snowpack mass and energy budgets in montane forests Accounting for fine-scale forest structure is necessary to model snowpack mass and energy budgets in montane forests

Accurately modeling the effects of variable forest structure and change on snow distribution and persistence is critical to water resource management. The resolution of many snow models is too coarse to represent heterogeneous canopy structure in forests, and therefore, most models simplify forest effects on snowpack mass and energy budgets. To quantify the loss of snowpack prediction...
Authors
Patrick D. Broxton, C. David Moeser, Adrian Harpold

South Africa's experimental fisheries closures and recovery of the endangered African penguin South Africa's experimental fisheries closures and recovery of the endangered African penguin

In a scientifically-transformative project, South Africa implemented a decade-long field experiment to understand how fisheries may be affecting its most iconic seabird, the African penguin Spheniscus demersus. This unique effort prohibits the take of anchovy and sardine within relatively small areas around four African penguin breeding colonies, two in the Benguela upwelling ecosystem...
Authors
William J. Sydeman, George L. Hunt, E.K. Pikitch, Julia K. Parrish, John F. Piatt, P Dee Boersma, Les Kaufman, Daniel W. Anderson, Sarah Ann Thompson, Richard B. Sherley

Mercury exposure of tidal marsh songbirds in the northeastern United States and its association with nest survival Mercury exposure of tidal marsh songbirds in the northeastern United States and its association with nest survival

The biogeochemistry of tidal marsh sediments facilitates the transformation of mercury (Hg) into the biologically available form methylmercury (MeHg), resulting in elevated Hg exposures to tidal marsh wildlife. Saltmarsh and Acadian Nelson’s sparrows (Ammospiza caudacutua and A. nelsoni subvirgatus, respectively) exclusively inhabit tidal marshes, potentially experiencing elevated risk...
Authors
Katherine J Ruskin, Garth Herring, Collin A. Eagles-Smith, Alyssa B. Eiklor, Chris S Elphick, Matthew A. Etterson, Chrisopher B. Field, Rebecca A. Longnecker, Adrienne I. Kovach, W Greg Shriver, James F. Walsh, Brian J. Olsen

Space-for-time is not necessarily a substitution when monitoring the distribution of pelagic fishes in the San Francisco Bay-Delta Space-for-time is not necessarily a substitution when monitoring the distribution of pelagic fishes in the San Francisco Bay-Delta

Occupancy models are often used to analyze long-term monitoring data to better understand how and why species redistribute across dynamic landscapes while accounting for incomplete capture. However, this approach requires replicate detection/non-detection data at a sample unit and many long-term monitoring programs lack temporal replicate surveys. In such cases, it has been suggested...
Authors
Adam Duarte, James T. Peterson

Long-term variation in polar bear body condition and maternal investment relative to a changing environment Long-term variation in polar bear body condition and maternal investment relative to a changing environment

In the Arctic, warming air and ocean temperatures have resulted in substantial changes to sea ice, which is primary habitat for polar bears (Ursus maritimus). Reductions in extent, duration, and thickness have altered sea ice dynamics, which influences the ability of polar bears to reliably access marine mammal prey. Because nutritional condition is closely linked to population vital...
Authors
Todd C. Atwood, Karyn D. Rode, David C. Douglas, Kristin S. Simac, Anthony Pagano, Jeffrey F. Bromaghin

Are drought indices and climate data good indicators of ecologically relevant soil moisture dynamics in drylands? Are drought indices and climate data good indicators of ecologically relevant soil moisture dynamics in drylands?

Droughts are disproportionately impacting global dryland regions where ecosystem health and function are tightly coupled to moisture availability. Drought severity is commonly estimated using algorithms such as the standardized precipitation-evapotranspiration index (SPEI), which can estimate climatic water balance impacts at various hydrologic scales by varying computational length...
Authors
David Barnard, Matthew J. Germino, John B. Bradford, Rory O’Connor, Caitlin M. Andrews, Robert K Shriver
Was this page helpful?