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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.

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Defining the hafnium isotopic signature of the Appalachian orogen through analysis of detrital zircons from modern fluvial sediments Defining the hafnium isotopic signature of the Appalachian orogen through analysis of detrital zircons from modern fluvial sediments

Fluvial sediments are the product of erosion, weathering, and transport of bedrock within a well-defined catchment area, and their constituent grains may therefore record valuable information about the lithological and geochemical properties of geologic units within the upstream drainage. Analysis of U-Pb ages and Lu/Hf isotopic values in detrital zircon grains from major rivers in the...
Authors
John W. Counts, William H. Craddock, Jared T. Gooley

Exposure to and biomarker responses from legacy and emerging contaminants along three drainages in the Milwaukee Estuary, Wisconsin, USA Exposure to and biomarker responses from legacy and emerging contaminants along three drainages in the Milwaukee Estuary, Wisconsin, USA

Legacy contaminants and contaminants of emerging concern (CECs) were assessed in tree swallow (Tachycineta bicolor) tissue and diet samples from three drainages in the Milwaukee estuary, Wisconsin, USA, to understand exposures and possible biomarker responses. Two remote Wisconsin lakes were assessed for comparative purposes. Bioaccumulative classes of contaminants, such as...
Authors
Christine M. Custer, Thomas W. Custer, Paul M. Dummer, Sandra L. Schultz, Natalie Karouna-Renier, Chi Yen Tseng, Cole W. Matson

Novel approach for ranking DEMs: Copernicus DEM improves one arc second open global topography Novel approach for ranking DEMs: Copernicus DEM improves one arc second open global topography

We present a practical approach to intercompare a range of candidate digital elevation models (DEMs) based on predefined criteria and a statistically sound ranking approach. The presented approach integrates the randomized complete block design (RCBD) into a novel framework for DEM comparison. The method presented provides a flexible, statistically sound, and customizable tool for...
Authors
Conrad Bielski, Carlos Lopez-Vazquez, Carlos H. Grohmann, Peter L. Guth, Laurence Hawker, Dean B. Gesch, Sebastiano Trevisani, Virginia Herrera-Cruz, Serge Riazanoff, Axel Corseaux, Hannes I. Reuter, Peter Strobl

Climate and landform interact to control the source and transport of nitrate in Pacific Northwest rivers Climate and landform interact to control the source and transport of nitrate in Pacific Northwest rivers

The hydrological effects of climate change are documented in many regions; however, climate-driven impacts to the source and transport of river nutrients remain poorly understood. Understanding the factors controlling nutrient dynamics across river systems is critical to preserve ecosystem function yet challenging given the complexity of landscape and climate interactions. Here, we...
Authors
Elizabeth J. Elmstrom, Gordon W. Holtgrieve, Mark David Scheuerell, Andrew J. Schauer, Karrin Leazer

GRACE and GRACE Follow-On gravity observations of intermediate-depth earthquakes contrasted with those of shallow events GRACE and GRACE Follow-On gravity observations of intermediate-depth earthquakes contrasted with those of shallow events

Earthquakes involve mass redistribution within the solid Earth and the ocean, and as a result, perturb the Earth's gravitational field. For most of the shallow ( 8.0, the GRACE satellite gravity measurements suggest considerable volumetric disturbance of rocks. At a spatial scale of hundreds of km, the effect of volumetric change exceeds gravity change by vertical deformation; for...
Authors
Shin-Chan Han, Jeanne Sauber, Taco Broerse, Frederick Pollitz, Emile Okal, Taehwan Jeon, Ki-Weon Seo, Richard Stanaway

PFAS river export analysis highlights the urgent need for catchment-scale mass loading data PFAS river export analysis highlights the urgent need for catchment-scale mass loading data

Source apportionment of per- and polyfluoroalkyl substances (PFAS) requires an understanding of the mass loading of these compounds in river basins. However, there is a lack of temporally variable and catchment-scale mass loading data, meaning identification and prioritization of sources of PFAS to rivers for management interventions can be difficult. Here, we analyze PFAS concentrations...
Authors
Patrick Byrne, William M. Mayes, Alun L. James, Sean Comber, Emma Biles, Alex Riley, Robert L. Runkel

How quickly do oil and gas wells “Water Out”? Quantifying and contrasting water production trends How quickly do oil and gas wells “Water Out”? Quantifying and contrasting water production trends

Water production from petroleum (oil and natural gas) wells is a topic of increasing environmental and economic importance, yet quantification efforts have been limited to date, and patterns between and within petroleum plays are largely unscrutinized. Additionally, classification of reservoirs as “unconventional” (also known as “continuous”) carries scientific and regulatory importance...
Authors
Seth S. Haines, Brian A. Varela, Marilyn E. Tennyson, Nicholas J. Gianoutsos

Adaptive resource management: Achieving functional eradication of invasive snakes to benefit avian conservation Adaptive resource management: Achieving functional eradication of invasive snakes to benefit avian conservation

Natural resource management often co-occurs with considerable uncertainty. One approach to mitigating uncertainty is through adaptive resource management (ARM), a specialized form of structured decision-making that modifies management decisions or actions through monitoring and implementation.Here, we present a case study on the attempted eradication of an invasive brown treesnake (Boiga
Authors
Melia Gail Nafus, Amanda Reyes, Thomas Fies, Scott Michael Goetz

Revisiting the physical processes controlling the tropical atmospheric circulation changes during the Mid-Piacenzian Warm Period Revisiting the physical processes controlling the tropical atmospheric circulation changes during the Mid-Piacenzian Warm Period

The Mid-Piacenzian Warm Period (MPWP; 3.0–3.3 Ma), a warm geological period about three million years ago, has been deemed as a good past analog for understanding the current and future climate change. Based on 12 climate model outputs from Pliocene Model Intercomparison Project Phase 2 (PlioMIP2), we investigate tropical atmospheric circulation (TAC) changes under the warm MPWP and...
Authors
Ke Zhang, Yong Sun, Xuan Zhang, Christian Stepanek, Ran Feng, Daniel Hill, Gerrit Lohmann, Aisling M Dolan, Alan M Haywood, Ayako Abe-Ouchi, Bette Otto-Bliesner, Camille Contoux, Deepak Chandan, Gilles Ramstein, Harry J. Dowsett, Julia C. Tindall, Michiel Baatsen, Ning Tan, William Richard Peltier, Qiang Liu, Wing-Le Chan, Xin Wang, Xu Zhang

Precipitation uncertainty estimation and rainfall-runoff model calibration using iterative ensemble smoothers Precipitation uncertainty estimation and rainfall-runoff model calibration using iterative ensemble smoothers

The introduction of iterative ensemble smoothers (IES) for parameter calibration opens avenues for expanding parameter space in surface water hydrologic modeling. Here, we have introduced independent parameters into a model calibration experiment to estimate errors in rainfall forcing data. This approach has the potential to estimate rainfall errors using other hydrological observations...
Authors
Davide Zoccatelli, Daniel B. Wright, Jeremy T. White, Michael N. Fienen, Guo Yu

Declining pronghorn (Antilocapra americana) population productivity caused by woody encroachment and oil and gas development Declining pronghorn (Antilocapra americana) population productivity caused by woody encroachment and oil and gas development

Conservation is increasingly focused on preventing losses in species’ populations before they occur. Tracking changes in demographic parameters that can impact a population’s resilience in response to drivers of global change can support early conservation efforts. We assessed trends in population productivity (late summer juveniles per 100 females) relative to drivers of global change...
Authors
Victoria M. Donovan, Jeffrey L. Beck, Carissa L. Wonkka, Caleb Powell Roberts, Craig R. Allen, Dirac Twidwell

Assessing trade-offs in developing a landscape-scale nest monitoring programme for a threatened shorebird Assessing trade-offs in developing a landscape-scale nest monitoring programme for a threatened shorebird

Effective monitoring of wildlife species requires thorough planning and development of survey programmes that can address management and conservation objectives. Decisions about monitoring programmes include where to survey, survey design and how much effort to allocate at survey sites are typically predicated on limited budgets and available resources. When the scope of inference...
Authors
Kristen S. Ellis, Michael J. Anteau, Garrett J. MacDonald, Megan M. Ring, Mark H. Sherfy, Rose J. Swift, Dustin L. Toy
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