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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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Geology and stratigraphic correlation of the Murray and Carolyn Shoemaker formations across the Glen Torridon region, Gale crater, Mars Geology and stratigraphic correlation of the Murray and Carolyn Shoemaker formations across the Glen Torridon region, Gale crater, Mars

The Glen Torridon (GT) region within Gale crater, Mars, occurs in contact with the southern side of Vera Rubin ridge (VRR), a well-defined geomorphic feature that is comparatively resistant to erosion. Prior to detailed ground-based investigation of GT, its geologic relationship with VRR was unknown. Distinct lithologic subunits within the Jura member (Murray formation), which forms the...
Authors
Christopher M. Fedo, Alexander Bryk, Lauren A. Edgar, Kristen A. Bennett, Valerie K. Fox, William E. Dietrich, Steve G. Banham, Sanjeev Gupta, Kathryn M. Stack, Rebecca Williams, John P. Grotzinger, Nathan Stein, Dave Rubin, Gwenael Caravaca, Ray E. Arvidson, Madison N Hughes, Abigail A. Fraeman, Ashwin R. Vasavada, Juergen Schieber, Brad Sutter

Hepatic gene expression profiling of American kestrels (Falco sparverius) exposed in ovo to three alternative brominated flame retardants Hepatic gene expression profiling of American kestrels (Falco sparverius) exposed in ovo to three alternative brominated flame retardants

A number of brominated flame retardants (BFRs) have been reported to interfere with the thyroid signaling pathway and cause oxidative stress in birds, yet the underlying shifts in gene expression associated with these effects remain poorly understood. In this study, we measured hepatic transcriptional responses of 31 genes in American kestrel (Falco sparverius) hatchlings following in...
Authors
Christopher G. Goodchild, Natalie Karouna-Renier, Ryan P. Braham, Paula F. P. Henry, Robert J. Letcher, Kim J. Fernie

Atlantic spotted and bottlenose dolphin sympatric distribution in nearshore waters off Bimini, The Bahamas, 2003–2018 Atlantic spotted and bottlenose dolphin sympatric distribution in nearshore waters off Bimini, The Bahamas, 2003–2018

Within nearshore waters off Bimini, The Bahamas, Atlantic spotted (Stenella frontalis) and common bottlenose (Tursiops truncatus) dolphins are sympatric but separated spatially in different geographic areas and water depth ranges. Afternoon surveys during summer months across a 16-year period showed S. frontalis used the northern part of the nearshore area more, while T. truncatus used...
Authors
Alexis L. Levengood, Kelly Melillo-Sweeting, Christine Ribic, Albert J. Beck, Kathleen M. Dudzinski

Climate matching with the climatchR R package Climate matching with the climatchR R package

Climate matching allows comparisons of climatic conditions between different locations to understand location and species range climatic suitability. The approach may be used as part of horizon scanning exercises such as those conducted for invasive species. We implemented the CLIMATCH algorithm into an R package, climatchR. The package allows automated and scripted climate matching...
Authors
Richard A. Erickson, Peder S Engelstad, Catherine S. Jarnevich, Helen Sofaer, Wesley M. Daniel

The influence of satellite-derived environmental and oceanographic parameters on marine turtle time at surface in the Gulf of Mexico The influence of satellite-derived environmental and oceanographic parameters on marine turtle time at surface in the Gulf of Mexico

The aftermath of the 2010 Deepwater Horizon oil spill highlighted the lack of baseline spatial, behavioral, and abundance data for many species, including imperiled marine turtles, across the Gulf of Mexico. The ecology of marine turtles is closely tied to their vertical movements within the water column and is therefore critical knowledge for resource management in a changing ocean. A...
Authors
Kelsey E. Roberts, Lance P. Garrison, Joel G. Ortega-Ortiz, Chuanmin Hu, Yingjun Zhang, Christopher R. Sasso, Margaret Lamont, Kristen Hart

Development of a ddPCR assay for the detection of the Smoky Madtom (Noturus baileyi) from eDNA in stream water samples Development of a ddPCR assay for the detection of the Smoky Madtom (Noturus baileyi) from eDNA in stream water samples

The Smoky Madtom Noturus baileyi is a federally endangered species, whose native distribution includes lower Abrams Creek in Great Smoky Mountains National Park (GRSM) and Citico Creek in nearby Cherokee National Forest. Due to challenges for bio-monitoring posed by its nocturnality and cryptic life history, an environmental DNA (eDNA)-based approach for detection would be useful to...
Authors
Aaron W. Aunins, Michael S. Eackles, Paul E Super, Matt A. Kulp, Becky J Nichols, Barbara A. Lubinski, Cheryl L. Morrison, Timothy L. King

Using ecosystem services to identify inequitable outcomes in migratory species conservation Using ecosystem services to identify inequitable outcomes in migratory species conservation

Biodiversity conservation efforts have been criticized for generating inequitable socio-economic outcomes. These equity challenges are largely analyzed as place-based problems affecting local communities directly impacted by conservation programs. The conservation of migratory species extends this problem geographically since people in one place may benefit while those in another bear...
Authors
Charles C. Chester, Aaron M. Lien, Juanita Sundberg, James E. Diffendorfer, Columba Gonzales, Brady J. Mattsson, Rodrigo Medellin, Darius J. Semmens, Wayne E. Thogmartin, Jonathan J. Derbridge, Laura Lopez-Hoffman

Hydrologic connectivity and residence time affect the sediment trapping efficiency and dissolved oxygen concentrations of the Atchafalaya River Basin Hydrologic connectivity and residence time affect the sediment trapping efficiency and dissolved oxygen concentrations of the Atchafalaya River Basin

Little is known about water movement, volume, or residence time (RT), and how those characteristics affect sediment trapping efficiency (TE) and dissolved oxygen concentrations (DO) in the United States' largest remaining bottomland hardwood swamp, the Atchafalaya River Basin. To better understand these dynamics, this study used bathymetry, lidar, and stage records to determine volumes...
Authors
Daniel Kroes, Richard Day, Michael D. Kaller, Charles R. Demas, William E. Kelso, Tiffany Pasco, Raynie Harlan, Steven Roberts

A reproducible and reusable pipeline for segmentation of geoscientific imagery A reproducible and reusable pipeline for segmentation of geoscientific imagery

Segmentation of Earth science imagery is an increasingly common task. Among modern techniques that use Deep Learning, the UNet architecture has been shown to be a reliable for segmenting a range of imagery. We developed software–Segmentation Gym–to implement a data-model pipeline for segmentation of scientific imagery using a family of UNet models. With an existing set of imagery and...
Authors
Daniel D. Buscombe, Evan B. Goldstein

Rapid SNP genotyping, sex identification, and hybrid-detection in threatened bull trout Rapid SNP genotyping, sex identification, and hybrid-detection in threatened bull trout

We developed new bull trout genetic markers using Restriction-site Associated DNA sequencing (RAD-seq) to improve our ability to address questions important for their conservation and management. Samples from across the species range were sequenced and 5020 high quality single nucleotide polymorphism (SNP) loci were discovered, including hundreds with high heterozygosity (H > 0.30). We...
Authors
Stephen J. Amish, Shana Bernall, Patrick W. DeHaan, Michael A. Miller, Sean M. O'Rourke, Matthew Boyer, Clint C. Muhlfeld, Angela Lodmell, Robb F. Leary, Gordon Luikart

Simulation of heat flow in a synthetic watershed: Lags and dampening across multiple pathways under a climate-forcing scenario Simulation of heat flow in a synthetic watershed: Lags and dampening across multiple pathways under a climate-forcing scenario

Although there is widespread agreement that future climates tend toward warming, the response of aquatic ecosystems to that warming is not well understood. This work, a continuation of companion research, explores the role of distinct watershed pathways in lagging and dampening climate-change signals. It subjects a synthetic flow and transport model to a 30-year warming signal based on...
Authors
Daniel T. Feinstein, Randall J. Hunt, Eric D. Morway

Avian influenza antibody prevalence increases with mercury contamination in wild waterfowl Avian influenza antibody prevalence increases with mercury contamination in wild waterfowl

Environmental contamination is widespread and can negatively impact wildlife health. Some contaminants, including heavy metals, have immunosuppressive effects, but prior studies have rarely measured contamination and disease simultaneously, which limits our understanding of how contaminants and pathogens interact to influence wildlife health. Here, we measured mercury concentrations...
Authors
Claire Stewart Teitelbaum, Joshua T. Ackerman, Mason A. Hill, Jaqueline M. Satter, Michael L. Casazza, Susan E.W. De La Cruz, Walter M. Boyce, Evan James Buck, John M. Eadie, Mark P. Herzog, Elliott Matchett, Cory T. Overton, Sarah H. Peterson, Magdalena Plancarte, Andrew M. Ramey, Jeffery D. Sullivan, Diann Prosser
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