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The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
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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Geoenvironmental model for roll-type uranium deposits in the Texas Gulf Coast Geoenvironmental model for roll-type uranium deposits in the Texas Gulf Coast
Geoenvironmental models were formulated by the U.S. Geological Survey in the 1990s to describe potential environmental effects of extracting different types of ore deposits in different geologic and climatic regions. This paper presents a geoenvironmental model for roll-front (roll-type) uranium deposits in the Texas Coastal Plain. The model reviews descriptive and quantitative...
Authors
Katherine Walton-Day, Johanna Blake, Robert R. Seal,, Tanya J. Gallegos, Jean Dupree, Kent D Becher
Comparison of radium analytical methods for municipal drinking water well operation Comparison of radium analytical methods for municipal drinking water well operation
Radium (Ra) is a geogenic contaminant that occurs at high levels in the Midwestern Cambrian-Ordovician aquifer system (MCOAS), a regionally important sandstone and carbonate drinking water aquifer. Water utilities using the MCOAS often must adopt treatment methods or use alternative water sources to maintain high-quality drinking water. Here, we show that Ra in water obtained from a...
Authors
Madeleine J Mathews, Sean R Scott, Randall J. Hunt, Matthew Ginder-Vogel
Assessing runoff and erosion on woodland-encroached sagebrush steppe using the Rangeland Hydrology and Erosion Model Assessing runoff and erosion on woodland-encroached sagebrush steppe using the Rangeland Hydrology and Erosion Model
The transition of sagebrush-dominated (Artemisia spp.) shrublands to pinyon (Pinus spp.) and juniper (Juniperus spp.) woodlands markedly alters resource-conserving vegetation structure typical of these landscapes. Land managers and scientists in the western United States need knowledge and predictive tools for assessment and effective targeting of tree-removal treatments to conserve or...
Authors
C. Jason Williams, Frederick B. Pierson, Osama Z. Al-Hamdan, S. Kossi Nouwakpo, Justin C. Johnson, Viktor O. Polyakov, Patrick R. Kormos, Scott Shaff, Kenneth E. Spaeth
What is a biocrust? A refined, contemporary definition for a broadening research community What is a biocrust? A refined, contemporary definition for a broadening research community
Studies of biological soil crusts (biocrusts) have proliferated over the last few decades. The biocrust literature has broadened, with more studies assessing and describing the function of a variety of biocrust communities in a broad range of biomes and habitats and across a large spectrum of disciplines, and also by the incorporation of biocrusts into global perspectives and...
Authors
Bettina Weber, Jayne Belnap, Burkhard Budel, Anita J. Antoninka, Nichole N. Barger, V Bala Chaudhary, Anthony Darrouzet-Nardi, David J. Eldridge, Akasha M. Faist, Scott Ferrenberg, Caroline Havrilla, Elisabeth Huber-Sannwald, Oumarou Malam Issa, Fernando T. Maestre, Sasha C. Reed, Emilio Rodriguez-Caballero, Colin L Tucker, Kristina E. Young, Yuanming Zhang, Yunge Zhao, Xiaobing Zhou, Matthew A. Bowker
Cryptic population decrease due to invasive species predation in a long-lived seabird supports need for eradication Cryptic population decrease due to invasive species predation in a long-lived seabird supports need for eradication
Invasive species are one of the greatest drivers of biodiversity loss worldwide, and the eradication of invasive species from islands is a highly efficient management strategy. Because eradication operations require large financial investments, uncertainty over the magnitude of impacts of both invasive species and their removal can impede the willingness of decision makers to invest in...
Authors
Steffen Oppel, Bethany L. Clark, Michelle M. Risi, Catharine Horswill, Sarah J. Converse, Christopher W. Jones, Alexis M. Osborne, Kim Stevens, Vonica Perold, Alexander L. Bond, Ross M. Wanless, Richard Cuthbert, John Cooper, Peter G. Ryan
Morphology and paleohydrology of intracrater alluvial fans north of Hellas Basin, Mars Morphology and paleohydrology of intracrater alluvial fans north of Hellas Basin, Mars
Alluvial fans and sinuous ridges are both important records of the history of fluvial activity on Mars, and they often occur together. We present observations of alluvial fans, many of which exhibit inverted relief, in five craters in the region north of Hellas basin. The observed fans ranged in size from ~10 to 820 km2. We identified three primary fan surface morphology classes (chute...
Authors
Ryan B. Anderson, Rebecca Williams, Amber L. Gullikson, William Nelson
Maturation study of vitrinite in carbonaceous shales and coals: Insights from hydrous pyrolysis Maturation study of vitrinite in carbonaceous shales and coals: Insights from hydrous pyrolysis
The presence of vitrinite in sedimentary rocks of post-Silurian age allows its reflectance to be used to estimate the thermal maturation of organic matter in petroleum systems. Increasing reflectance of vitrinite, which is primarily driven by aromaticity, depends primarily on the time and temperature attributes of its evolutionary pathway. This study evaluated carbonaceous shales...
Authors
Divya K. Mishra, Paul C. Hackley, Aaron M. Jubb, Margaret M. Sanders, Shailesh Agrawal, Atul K. Varma
Reproductive indices and observations of mass ovarian follicular atresia in hatchery-origin pallid sturgeon Reproductive indices and observations of mass ovarian follicular atresia in hatchery-origin pallid sturgeon
The Pallid Sturgeon (Scaphirhynchus albus) Conservation Propagation and Stocking Program began stocking in the Missouri River above Fort Peck Reservoir in 1998 with 1997-year-class pallid sturgeon. Within the 1997-year class, all hatchery-origin pallid sturgeon females that reached reproductive maturation by 2016 underwent mass ovarian follicular atresia. Using combined historical and...
Authors
Tanner L. Cox, Christopher S. Guy, Luke M. Holmquist, Molly A. H. Webb
Primary production responses to extreme changes in North American Monsoon precipitation vary by elevation and plant functional composition through time Primary production responses to extreme changes in North American Monsoon precipitation vary by elevation and plant functional composition through time
Primary production in dryland ecosystems is limited by water availability and projected to be strongly affected by future shifts in seasonal precipitation. Warm-season precipitation derived from the North American Monsoon contributes 40% of annual precipitation to dryland ecosystems in the southwestern U.S. and is projected to become more variable. However, there is large uncertainty on...
Authors
Seth M. Munson, John B. Bradford, Bradley J. Butterfield, Jennifer R. Gremer
Resisting-accepting-directing: Ecosystem management guided by an ecological resilience assessment Resisting-accepting-directing: Ecosystem management guided by an ecological resilience assessment
As anthropogenic influences push ecosystems past tipping points and into new regimes, complex management decisions are complicated by rapid ecosystem changes that may be difficult to reverse. For managers who grapple with how to manage ecosystems under novel conditions and heightened uncertainty, advancing our understanding of regime shifts is paramount. As part of an ecological...
Authors
Kristen L. Bouska, Nathan R. De Jager, Jeffrey N. Houser
Data-driven modeling of wind waves in upper Delaware Bay with living shorelines Data-driven modeling of wind waves in upper Delaware Bay with living shorelines
Living shoreline projects have been built to preserve coastal ecosystems under future climate change and sea level rise. To quantify the wave power variation across living shorelines, the wave characteristics around the constructed oyster reefs (CORs) in upper Delaware Bay were investigated in this study. Wave parameters seaward and shoreward of CORs were recorded by wave gauges in early...
Authors
Nan Wang, Q. Chen, Ling Zhu, Hongqing Wang
Assessing wave attenuation with rising sea levels for sustainable oyster reef-based living shorelines Assessing wave attenuation with rising sea levels for sustainable oyster reef-based living shorelines
In densely populated coastal areas with sea-level rise (SLR), protecting the shorelines against erosion due to the wave impact is crucial. Along with many engineered structures like seawalls and breakwaters, there are also green structures like constructed oyster reefs (CORs) that can not only attenuate the incident waves but also grow and maintain pace with SLR. However, there is a lack...
Authors
Reza Salatin, Hongqing Wang, Q. Chen, Ling Zhu