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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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Detailed 40Ar/39Ar geochronology of the Loyalty and Three Kings Ridges clarifies the extent and sequential development of Eocene to Miocene southwest Pacific remnant volcanic arcs Detailed 40Ar/39Ar geochronology of the Loyalty and Three Kings Ridges clarifies the extent and sequential development of Eocene to Miocene southwest Pacific remnant volcanic arcs

The 2015 VESPA voyage (Volcanic Evolution of South Pacific Arcs) was a seismic and rock dredging expedition to the Loyalty and Three Kings Ridges and South Fiji Basin. In this paper we present 33 40Ar/39Ar, 22 micropaleontological, and two U/Pb ages for igneous and sedimentary rocks from 33 dredge sites in this little-studied part of the southwest Pacific Ocean. Igneous rocks include...
Authors
Phillip B. Gans, Nick Mortimer, M. Patriat, Rose E. Turnbull, M.P. Crundwell, A. Agranier, Andrew T. Calvert, G. Seward, Samuel Etienne, P.M.J. Durance, H.J. Campbell, Julien Collot

Distributions of Cisco (Coregonus artedi) in the upper Great Lakes in the mid-twentieth century, when populations were in decline Distributions of Cisco (Coregonus artedi) in the upper Great Lakes in the mid-twentieth century, when populations were in decline

The restoration of the once abundant Cisco (Coregonus artedi) is a management interest across the Laurentian Great Lakes. To inform the restoration, we (1) described historical distributions of Cisco and (2) explored whether non-indigenous Rainbow Smelt (Osmerus mordax) and Alewife (Alosa pseudoharengus) played a role in the decline of Cisco populations across the upper Great Lakes (i.e...
Authors
Yu-Chun Kao, Renee Elizabeth Renauer, David B. Bunnell, Owen Gorman, Randy L. Eshenroder

Near-term forecasts of stream temperature using deep learning and data assimilation in support of management decisions Near-term forecasts of stream temperature using deep learning and data assimilation in support of management decisions

Deep learning (DL) models are increasingly used to make accurate hindcasts of management-relevant variables, but they are less commonly used in forecasting applications. Data assimilation (DA) can be used for forecasts to leverage real-time observations, where the difference between model predictions and observations today is used to adjust the model to make better predictions tomorrow...
Authors
Jacob Aaron Zwart, Samantha K. Oliver, William Watkins, Jeffrey Michael Sadler, Alison P. Appling, Hayley R. Corson-Dosch, Xiaowei Jia, Vipin Kumar, Jordan Read

Investigating effects of climate-induced changes in water temperature and diet on mercury concentrations in an Arctic freshwater forage fish Investigating effects of climate-induced changes in water temperature and diet on mercury concentrations in an Arctic freshwater forage fish

The amount of mercury (Hg) in Arctic lake food webs is, and will continue to be, affected by rapid, ongoing climate change. At warmer temperatures, fish require more energy to sustain growth; changes in their metabolic rates and consuming prey with potentially higher Hg concentrations could result in increased Hg accumulation. To examine the potential implications of climate warming on...
Authors
Sarah M. Laske, Samantha M. Burke, Michael P. Carey, Heidi K. Swanson, Christian E. Zimmerman

Revised age and regional correlations of Cenozoic strata on Bat Mountain, Death Valley region, California, USA, from zircon U-Pb geochronology of sandstones and ash-fall tuffs Revised age and regional correlations of Cenozoic strata on Bat Mountain, Death Valley region, California, USA, from zircon U-Pb geochronology of sandstones and ash-fall tuffs

Basin analysis and tectonic reconstructions of the Cenozoic history of the Death Valley region, California, USA, are hindered by a lack of volcanic (tuff) age control in many stratigraphic successions exposed in the Grapevine and Funeral Mountains of California, USA. Although maximum depositional ages (MDAs) interpreted from detrital zircon U-Pb data may be a promising alternative to...
Authors
Theresa Maude Schwartz, Amanda Kate Souders, Jens-Erik Lundstern, Amy K. Gilmer, Ren A. Thompson

Do unpublished data help to redraw distributions? The case of the spectacled bear in Peru Do unpublished data help to redraw distributions? The case of the spectacled bear in Peru

Data availability remains a principal factor limiting the use of species distribution models (SDMs) as tools for wildlife conservation and management of rare species. Although data collected in systematic and rigorous fashion are preferable, available data for most species of conservation interest are usually low in both quality and number. Here we show that combining records published...
Authors
Nereyda Falconi, John T. Finn, Todd K. Fuller, John F. Organ

Models combining multiple scales of inference capture hydrologic and climatic drivers of riparian tree distributions Models combining multiple scales of inference capture hydrologic and climatic drivers of riparian tree distributions

Predicting species geographic distributions is key to managing invasive species, conserving biodiversity, and understanding species' environmental requirements. Species distribution models (SDMs) commonly focus on climatic predictors, but other environmental factors can also be essential, particularly for species with specialized habitats defined by hydrologic, topographic, or edaphic...
Authors
Laura G Perry, Catherine S. Jarnevich, Patrick B. Shafroth

Analysis of per capita contributions from a spatial model provides strategies for controlling spread of invasive carp Analysis of per capita contributions from a spatial model provides strategies for controlling spread of invasive carp

Metapopulation models may be applied to inform natural resource management to guide actions targeted at location-specific subpopulations. Model insights frequently help to understand which subpopulations to target and highlight the importance of connections among subpopulations. For example, managers often treat aquatic invasive species populations as discrete populations due to...
Authors
Donald R. Schoolmaster, Alison A. Coulter, Jahn L. Kallis, David C. Glover, John M. Dettmers, Richard A. Erickson

Sharing land via keystone structure: Retaining naturally regenerated trees may efficiently benefit birds in plantations Sharing land via keystone structure: Retaining naturally regenerated trees may efficiently benefit birds in plantations

Meeting food/wood demands with increasing human population and per-capita consumption is a pressing conservation issue, and is often framed as a choice between land sparing and land sharing. Although most empirical studies comparing the efficacy of land sparing and sharing supported land sparing, land sharing may be more efficient if its performance is tested by rigorous experimental...
Authors
Yuichi Yamaura, Akira Unno, J. Andrew Royle

Hydrologic and landscape controls on dissolved organic matter composition across western North American Arctic lakes Hydrologic and landscape controls on dissolved organic matter composition across western North American Arctic lakes

Northern high-latitude lakes are hotspots for cycling dissolved organic carbon (DOC) inputs from allochthonous sources to the atmosphere. However, the spatial distribution of lake dissolved organic matter (DOM) is largely unknown across Arctic-boreal regions with respect to the surrounding landscape. We expand on regional studies of northern high-latitude DOM composition by integrating...
Authors
Martin R. Kurek, Fenix Garcia-Tigreros, Kimberly Wickland, Karen E. Frey, Mark Dornblaser, Robert G. Striegl, Sydney F. Niles, Amy M. McKenna, Pieter J.K Aukes, Ethan D. Kyzivat, Chao Wang, Tamlin M. Pavelsky, Laurence C. Smith, Sherry L. Schiff, David Butman, Robert G.M. Spencer

A genetic warning system for a hierarchically structured wildlife monitoring framework A genetic warning system for a hierarchically structured wildlife monitoring framework

Genetic variation is a well-known indicator of population fitness yet is not typically included in monitoring programs for sensitive species. Additionally, most programs monitor populations at one scale, which can lead to potential mismatches with ecological processes critical to species' conservation. Recently developed methods generating hierarchically nested population units (i.e...
Authors
Shawna J Zimmerman, Cameron L. Aldridge, Michael S. O’Donnell, David R. Edmunds, Peter S. Coates, Brian G. Prochazka, Jennifer A. Fike, Todd B. Cross, Bradley C. Fedy, Sara J. Oyler-McCance

Comparison of two estrogen chemically activated luciferase expression cell bioassays to liquid chromatography–mass spectrometry for quantifying estrone in water samples Comparison of two estrogen chemically activated luciferase expression cell bioassays to liquid chromatography–mass spectrometry for quantifying estrone in water samples

Chemically activated luciferase expression (CALUX) cell bioassays are popular tools for assessing endocrine activity of chemicals such as certain environmental contaminants. Although activity equivalents can be obtained from CALUX analysis, directly comparing these equivalents to those obtained from analytical chemistry methods can be problematic because of the complexity of endocrine...
Authors
Jennifer C. Brennan, Abigail Henke, Robert Gale, Diane K. Nicks, Donald Tillitt
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