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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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Rapa Nui (Easter Island) Rano Raraku crater lake basin: Geochemical characterization and implications for the Ahu-Moai Period Rapa Nui (Easter Island) Rano Raraku crater lake basin: Geochemical characterization and implications for the Ahu-Moai Period
Rano Raraku, the crater lake constrained by basaltic tuff that served as the primary quarry used to construct the moai statues on Rapa Nui (Easter Island), has experienced fluctuations in lake level over the past centuries. As one of the only freshwater sources on the island, understanding the present and past geochemical characteristics of the lake water is critical to understand if the...
Authors
Elena Argiriadis, Mara Bortolini, Natalie Kehrwald, Marco Roman, Clara Turetta, Shahpara Hanif, Evans Osayuki Erhendi, Jose Miguel Ramirez Aliaga, David B. McWethy, Amy E. Myrbo, Anibal Pauchard, Carlo Barbante, Dario Battistel
A new approach to evaluate and reduce uncertainty of model-based biodiversity projections for conservation policy formulation A new approach to evaluate and reduce uncertainty of model-based biodiversity projections for conservation policy formulation
Biodiversity projections with uncertainty estimates under different climate, land-use, and policy scenarios are essential to setting and achieving international targets to mitigate biodiversity loss. Evaluating and improving biodiversity predictions to better inform policy decisions remains a central conservation goal and challenge. A comprehensive strategy to evaluate and reduce...
Authors
Bonnie Myers, Sarah R. Weiskopf, Alexey N. Shiklomanov, Simon Ferrier, Ensheng Weng, Kimberly Ann Casey, Michael Harfoot, Stephen Jackson, Allison K. Leidner, Timothy M. Lenton, Gordon Luikart, Hiroyuki Matsuda, Nathalie Pettorelli, Isabel M. D. Rosa, Alexander C. Ruane, Gabriel B. Senay, Shawn P. Serbin, Derek P. Tittensor, Beard
Feather corticosterone reveals developmental challenges in a long-term study of juvenile northern spotted owls Feather corticosterone reveals developmental challenges in a long-term study of juvenile northern spotted owls
Corticosterone is a steroid hormone integral to a variety of physiological pathways and is strongly associated with the vertebrate stress response. In avian species, circulating corticosterone is sequestered into developing feathers and is used as an indicator of energy allocation during feather growth and widely applied in conservation physiology.The northern spotted owl Strix...
Authors
Katie M. Dugger, Ashlee J. Mikkelsen, Damon B. Lesmeister, Kathleen M. O’Reilly
Feather corticosterone reveals developmental challenges in a long-term study of juvenile northern spotted owls Feather corticosterone reveals developmental challenges in a long-term study of juvenile northern spotted owls
Corticosterone is a steroid hormone integral to a variety of physiological pathways and is strongly associated with the vertebrate stress response. In avian species, circulating corticosterone is sequestered into developing feathers and is used as an indicator of energy allocation during feather growth and widely applied in conservation physiology.The northern spotted owl Strix...
Authors
Ashlee J. Mikkelsen, Damon B. Lesmeister, Kathleen M. O’Reilly, Katie M. Dugger
Persistent nitrate in alpine waters with changing atmospheric deposition and warming trends Persistent nitrate in alpine waters with changing atmospheric deposition and warming trends
Nitrate concentrations in high-elevation lakes of the Colorado Front Range remain elevated despite declining trends in atmospherically deposited nitrate since 2000. The current source of this elevated nitrate in surface waters remains elusive, given shifts in additional nitrogen sources via glacial inputs and atmospheric ammonium deposition. We present the complete isotopic composition...
Authors
Sydney C. Clark, Rebecca T. Barnes, Isabella A. Oleksy, Jill S. Baron, Meredith G. Hastings
Refinements to the Graves–Pitarka kinematic rupture generator, including a dynamically consistent slip‐rate function, applied to the 2019 Mw 7.1 Ridgecrest earthquake Refinements to the Graves–Pitarka kinematic rupture generator, including a dynamically consistent slip‐rate function, applied to the 2019 Mw 7.1 Ridgecrest earthquake
The main objective of this study is to develop physics‐based constraints on the spatiotemporal variation of the slip‐rate function using a simplified dynamic rupture model. First, we performed dynamic rupture modeling of the 2019 Mw 7.1 Ridgecrest, California, earthquake, to analyze the effects of depth‐dependent stress and material friction on slip rate. Then, we used our modeling...
Authors
Arben Pitarka, Robert Graves, Kojiro Irikura, Ken Miyakoshi, Changjiang Wu, Hiroshi Kawase, Arthur Rodgers, David McCallen
Hazard characterization for alternative intensity measures using the total probability theorem Hazard characterization for alternative intensity measures using the total probability theorem
Since their inception in the 1980s, simplified procedures for the analysis of liquefaction hazards have typically characterized seismic loading using a combination of peak ground acceleration and earthquake magnitude. However, more recent studies suggest that certain evolutionary intensity measures (IMs) such as Arias intensity or cumulative absolute velocity may be more efficient and...
Authors
Michael W. Greenfield, Andrew James Makdisi
A comprehensive statewide spatiotemporal stream assessment of per- and polyfluoroalkyl substances (PFAS) in an agricultural region of the United States A comprehensive statewide spatiotemporal stream assessment of per- and polyfluoroalkyl substances (PFAS) in an agricultural region of the United States
Public concern regarding per- and polyfluoroalkyl substances (PFAS) has grown substantially in recent years. In addition, research has documented multiple potential agriculture-related release pathways for PFAS (e.g., biosolids and livestock manure). Nevertheless, little research on the environmental prevalence of PFAS has been conducted in agricultural regions of the United States. To...
Authors
Dana W. Kolpin, Laura E. Hubbard, D.M. Cwiertny, Shannon M. Meppelink, D.A. Thompson, James L. Gray
Disentangling stationary and dynamic estuarine fish habitat to inform conservation: Species-specific responses to physical habitat and water quality in San Francisco Estuary Disentangling stationary and dynamic estuarine fish habitat to inform conservation: Species-specific responses to physical habitat and water quality in San Francisco Estuary
Estuaries represent critical aquatic habitat that connects surface water distributed between Earth’s landmasses and oceans. They are dynamic transitional ecosystems, which provide important habitat for fishes and other aquatic organisms. Effective conservation of species inhabiting estuaries requires knowledge of the habitat features that drive their abundance and distribution. We sought...
Authors
Frederick V. Feyrer, Matthew J. Young, Brock Huntsman, Larry R. Brown
Hierarchical functional response of a forager on a wetland landscape Hierarchical functional response of a forager on a wetland landscape
We show that for some foragers the form that a functional response takes depends on the temporal and spatial scales considered. In representing the consumption rate of an organism, it may be necessary to use a hierarchy of functional responses. Consider, for example, a wading bird foraging in wetland landscape characterized by a spatial distribution of potential foraging sites, such as...
Authors
Don DeAngelis, Simeon Yurek, Stephen Tennenbaum, Hyo Won Lee
Characterizing downstream migration timing of American Eels using commercial catch data in the Penobscot and Delaware rivers Characterizing downstream migration timing of American Eels using commercial catch data in the Penobscot and Delaware rivers
Adult “silver-phase” American Eels Anguilla rostrata were a focus of commercial fisheries in the 1970s and 1980s, but stocks have been depleted due to many anthropogenic factors. One significant source of mortality occurs during the downstream migration of eels when passing through turbines at hydroelectric facilities. We sought to construct a model to predict eel migration timing to...
Authors
Daniel M. Weaver, Douglas B. Sigourney, Mari-Beth Delucia, Joseph D. Zydlewski
Growth inhibition of the harmful alga Prymnesium parvum by plant-derived products and identification of ellipticine as highly potent allelochemical Growth inhibition of the harmful alga Prymnesium parvum by plant-derived products and identification of ellipticine as highly potent allelochemical
Prymnesium parvum is a toxin-producing harmful alga that has caused ecological and economic damage worldwide. Effective methods to control blooms of this species in the field, however, are unavailable. This study examined five natural compounds present in the invasive plant Arundo donax and one synthetic derivative (5,6-dichlorogramine) for their effect on P. parvum growth. All compounds...
Authors
Mousumi Mary, R. H. Rashel, Reynaldo Patino