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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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Modeling marsh dynamics using a 3-D coupled wave-flow-sediment model Modeling marsh dynamics using a 3-D coupled wave-flow-sediment model

Salt marshes are dynamic biogeomorphic systems that respond to external physical factors, including tides, sediment transport, and waves, as well as internal processes such as autochthonous soil formation. Predicting the fate of marshes requires a modeling framework that accounts for these processes in a coupled fashion. In this study, we implement two new marsh dynamic processes in the...
Authors
Tarandeep S. Kalra, Neil K. Ganju, Alfredo Aretxabaleta, Joel A. Carr, Zafer Defne, Julia Moriarty

Long-term Mississippi River trends expose shifts in the river load response to watershed nutrient balances between 1975 and 2017 Long-term Mississippi River trends expose shifts in the river load response to watershed nutrient balances between 1975 and 2017

Excess nutrients transported by the Mississippi River (MR) contribute to hypoxia in the Gulf of Mexico. Nutrient balances are key drivers to river nutrient loads and represent inputs (fertilizer, manure, deposition, wastewater, N-fixation, and weathering) minus outputs (nutrient uptake and removal in harvest, and N emissions). Here, we quantified annual changes in nitrogen (N) and...
Authors
Sarah M. Stackpoole, Robert D. Sabo, James A. Falcone, Lori A. Sprague

Small shorebirds feast on green slime to fuel their long migration Small shorebirds feast on green slime to fuel their long migration

Shorebirds wade in shallow waters along shorelines searching for food. More than a million shorebirds visit the San Francisco Estuary each year during their migration to feast on the insects, worms, clams, and crabs that live on or under the surface of the sand or mud. The abundant food in the Estuary provides shorebirds with the energy they need to migrate thousands of kilometers...
Authors
Laurie Anne Hall, Susan E.W. De La Cruz, Isa Woo, Tomohiro Kuwae, David Mcgovern Nelson, John Y. Takekawa

Magmatism, migrating topography, and the transition from Sevier shortening to Basin and Range extension, western United States Magmatism, migrating topography, and the transition from Sevier shortening to Basin and Range extension, western United States

The paleogeographic evolution of the western U.S. Great Basin from the Late Cretaceous to the Cenozoic is critical to understanding how the North American Cordillera at this latitude transitioned from Mesozoic shortening to Cenozoic extension. According to a widely applied model, Cenozoic extension was driven by collapse of elevated crust supported by crustal thicknesses that were...
Authors
Jens-Erik Lundstern, Elizabeth L. Miller

Does restoration of plant diversity trigger concomitant soil microbiome changes in dryland ecosystems? Does restoration of plant diversity trigger concomitant soil microbiome changes in dryland ecosystems?

Drylands are highly vulnerable to land degradation, and despite increasing efforts, restoration success remains low. Although often ignored in the design and deployment of management strategies, soil microbial communities might be critical for dryland restoration due to their central role in promoting soil stability, nutrient cycling and plant establishment.We collected soil samples from...
Authors
Ben Yang, Kathleen R. Balazs, Bradley J. Butterfield, Katherine M. Laushman, Seth M. Munson, Elise S. Gornish, Albert Barberan

Evaluation of intensity prediction equations (IPEs) for small-magnitude earthquakes Evaluation of intensity prediction equations (IPEs) for small-magnitude earthquakes

This study assesses existing intensity prediction equations (IPEs) for small unspecified magnitude (M ≤3.5) earthquakes at short hypocentral distances (⁠Dh⁠) and explores such earthquakes’ contribution to the felt shaking hazard. In particular, we consider IPEs by Atkinson and Wald (2007) and Atkinson et al. (2014), and evaluate their performance based on “Did You Feel It” (DYFI) reports...
Authors
Ganyu Teng, Jack W. Baker, David J. Wald

Evidence of glacial activity during MIS 4 in the Rocky Mountains, Colorado, USA Evidence of glacial activity during MIS 4 in the Rocky Mountains, Colorado, USA

The Ziegler Reservoir fossil site near Snowmass Village, Colorado, provides a rare opportunity to examine environmental conditions in the Rocky Mountains during marine isotope stage (MIS) 4 (71–57 ka). Although recognized as a global-scale cold event, MIS 4 is typically absent from Rocky Mountain glacial chronologies because the geologic evidence was covered or destroyed during the...
Authors
Jeffrey S. Honke, Jeffrey S. Pigati, J. Michael Daniels

Causes, consequences, and conservation of ungulate migration Causes, consequences, and conservation of ungulate migration

Our understanding of ungulate migration is advancing rapidly due to innovations in modern animal tracking. Herein, we review and synthesize nearly seven decades of work on migration and other long-distance movements of wild ungulates. Although it has long been appreciated that ungulates migrate to enhance access to forage, recent contributions demonstrate that their movements are fine...
Authors
Matthew J. Kauffman, Ellen O. Aikens, Saeideh Esmaeili, Petra Kaczensky, Arthur Middleton, Kevin L. Monteith, Thomas A. Morrison, Thomas Mueller, Hall Sawyer, Jacob R. Goheen

Nine-banded armadillo (Dasyrus novemcinctus) activity patterns are influenced by human activity Nine-banded armadillo (Dasyrus novemcinctus) activity patterns are influenced by human activity

As the human footprint upon the landscape expands, wildlife seeking to avoid human contact are losing the option of altering their spatial distribution and instead are shifting their daily activity patterns to be active at different times than humans. In this study, we used game cameras to evaluate how human development and activity were related to the daily activity patterns of the nine...
Authors
Brett Alexander DeGregorio, C. Gale, E. V. Lassiter, A. Massey, Caleb Powell Roberts, J. Veon

PlioMIP: The Pliocene Model Intercomparison Project PlioMIP: The Pliocene Model Intercomparison Project

PlioMIP is a network of paleoclimate modelers and geoscientists who, through the study of the mid-Pliocene Warm Period (mPWP ~3.3–3.0 million years ago), seek to understand the sensitivity of the climate system to forcings and examine how well models reproduce past climate change.
Authors
A. M. Haywood, Harry J. Dowsett

Movement dynamics and survival of stocked Colorado River Cutthroat Trout Movement dynamics and survival of stocked Colorado River Cutthroat Trout

The ability of native fish to establish self-sustaining populations when reintroduced to vacant habitats is variable. We evaluated factors that potentially affect the reintroduction success of juvenile Colorado River Cutthroat Trout Oncorhynchus clarkii pleuriticus that were reintroduced to an isolated watershed and were experiencing suboptimal survival and recruitment. We conducted a 3...
Authors
Alex G. LeCheminant, Gabriel M. Barrile, Shannon E. Albeke, Annika W. Walters

Species invasion progressively disrupts the trophic structure of native food webs Species invasion progressively disrupts the trophic structure of native food webs

Species invasions can have substantial impacts on native species and ecosystems, with important consequences for biodiversity. How these disturbances drive changes in the trophic structure of native food webs through time is poorly understood. Here, we quantify trophic disruption in freshwater food webs to invasion by an apex fish predator, lake trout, using an extensive stable isotope...
Authors
Charles Wainright, Clint C. Muhlfeld, James J. Elser, Samuel Bourret, Shawn P. Devlin
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