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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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Photogrammetry of the deep seafloor from archived unmanned submersible exploration dives Photogrammetry of the deep seafloor from archived unmanned submersible exploration dives

Large amounts of video images have been collected for decades by scientific and governmental organizations in deep (>1000 m) water using manned and unmanned submersibles and towed cameras. The collected images were analyzed individually or were mosaiced in small areas with great effort. Here, we provide a workflow for utilizing modern photogrammetry to construct virtual geological...
Authors
Claudia Flores, Uri S. ten Brink

Gape-limited invasive predator frequently kills avian prey that are too large to swallow Gape-limited invasive predator frequently kills avian prey that are too large to swallow

Gape-limited predators (e.g., snakes, many fish) are not generally expected to pose a predation threat to prey that are too large for them to swallow. However, the extent to which snakes predate on prey that exceed their gape limitation remains largely unknown. We conducted the first study to investigate the influence of both prey and predator sizes on the frequency of ingestion success...
Authors
Martin Kastner, Scott Michael Goetz, Kayla M Baker, Shane R. Siers, Eben H. Paxton, Melia Gail Nafus, Haldre Rogers

Evaluating mountain lion diet before and after a removal of feral horses in a semiarid environment Evaluating mountain lion diet before and after a removal of feral horses in a semiarid environment

Non-native species can affect ecosystems by influencing native predator-prey dynamics. Therefore, management interventions designed to remove non-natives may inadvertently lead to increased predation on native species. Feral horses are widely distributed throughout the arid parts of western North America. A growing body of research indicates that horses can be an important prey species...
Authors
Peter C. Iacono, Kathryn A. Schoenecker, Kezia R. Manlove, Pat J. Jackson, David C. Stoner

Cathodoluminescence imaging and spectrometry of a jadeite microbeam reference crystal: Detection of Ce3+ Cathodoluminescence imaging and spectrometry of a jadeite microbeam reference crystal: Detection of Ce3+

Options for selecting a high Na concentration mineral for instrument calibration that are suitably stable under the electron beam are limited [1]. NaCl (approximately a mass fraction of 39 % Na) is not practical for use alongside other embedded and polished materials in a mounted block of standards. While albite (NaAlSi3O8; approximately a mass fraction of 8 % Na) represents a typical...
Authors
Thomas Lameris, Heather A. Lowers, Scott A. Wight, Edward P. Vicenzi

Correlating quantified cathodoluminescence spectra in jadeite with micro-scale color measurements in visible-near infrared reflectance spectrometry Correlating quantified cathodoluminescence spectra in jadeite with micro-scale color measurements in visible-near infrared reflectance spectrometry

Cultures throughout history have valued jadeite jade (hereinafter jade), a natural material assemblage composed predominately of the NaAl endmember pyroxene, jadeite (NaAlSi2O6) that is prized for its mechanical properties and enticing coloration [1, 2]. The geological setting for the formation of jadeite-rich rocks and associated complex geochemical phenomena is well documented in the...
Authors
Edward P. Vicenzi, Thomas Lameris, Heather A. Lowers, Colin MacRae

Compositional and structural mapping of Northwest Africa 15507 angrite Compositional and structural mapping of Northwest Africa 15507 angrite

Angrite meteorites represent interesting sampling of planetary crustal environments. Quench-textured angrites with strong crystal zoning originated from the shallow surface region, with evidence of reducing conditions during solidification. Plutonic angrites have more coarse-grained igneous and metamorphic textures with comparatively less zoning and are interpreted as having equilibrated...
Authors
Heather A. Lowers, Paul C. Carpenter, Jay M. Thompson, Anthony Irving

Mercury concentrations in Seaside Sparrows and Marsh Rice Rats differ across the Mississippi River Estuary Mercury concentrations in Seaside Sparrows and Marsh Rice Rats differ across the Mississippi River Estuary

Mercury (Hg) concentrations and their associated toxicological effects in terrestrial ecosystems of the Gulf of Mexico are largely unknown. Compounding this uncertainty, a large input of organic matter from the 2010 Deepwater Horizon oil spill may have altered Hg cycling and bioaccumulation dynamics. To test this idea, we quantified blood concentrations of total mercury (THg) in Seaside...
Authors
Andrea Bonisoli-Alquati, Allyson K. Jackson, Collin A. Eagles-Smith, Sydney Moyo, Anna A. Perez-Umphre, Michael J. Polito, Allison M. Snider, S. Tyler Williams, Stefan Woltmann, Philip C. Stouffer, Sabrina S. Taylor

Assessing the attractiveness of native wildflower species to bees (Hymenoptera: Anthophila) in the southeastern United States Assessing the attractiveness of native wildflower species to bees (Hymenoptera: Anthophila) in the southeastern United States

Habitat loss, agricultural intensification, pesticide use, disease and climate change have contributed to the decline of numerous insect groups. Recent government initiatives have recognized the importance of supplementary wildflower plantings to support native bee populations, yet little information exists on the attractiveness of recommended plant species to bees.With the use of...
Authors
Anthony P. Abbate, Joshua W. Campbell, Steven Mark Grodsky, Geoffrey R. Williams

Projecting the long-term effects of large-scale human influence on the spatial and functional persistence of extant longleaf pine ecosystems in the Florida Flatwoods Pyrome Projecting the long-term effects of large-scale human influence on the spatial and functional persistence of extant longleaf pine ecosystems in the Florida Flatwoods Pyrome

Decades of human activities and fire suppression have adversely affected longleaf pine (Pinus palustris) ecosystems, which are home to high levels of diversity and endemism. These iconic ecosystems also now face challenges from urbanization and climate change, which will alter conservation outcomes over the remainder of the 21st century. To explore how long-term, large-scale human...
Authors
Lilian Hutchens, John A. Kupfer, Peng Gao, Georgina M. Sanchez, Ross K. Meentemeyer, Adam Terando, J. Kevin Hiers

Global variability of the composition and temperature at the 410-km discontinuity from receiver function analysis of dense arrays Global variability of the composition and temperature at the 410-km discontinuity from receiver function analysis of dense arrays

Seismic boundaries caused by phase transitions between olivine polymorphs in Earth's mantle provide thermal and compositional markers that inform mantle dynamics. Seismic studies of the mantle transition zone often use either global averaging with sparse arrays or regional sampling from a single dense array. The intermediate approach of this study utilizes many densely spaced seismic...
Authors
Margaret Elizabeth Glasgow, Hankui K. Zhang, Brandon Schmandt, Wen-Yi Zhou, Jinchi Zhang

A semi-mechanistic model for partitioning evapotranspiration reveals transpiration dominates the water flux in drylands A semi-mechanistic model for partitioning evapotranspiration reveals transpiration dominates the water flux in drylands

Popular evapotranspiration (ET) partitioning methods make assumptions that might not be well-suited to dryland ecosystems, such as high sensitivity of plant water-use efficiency (WUE) to vapor pressure deficit (VPD). Our objectives were to (a) create an ET partitioning model that can produce fine-scale estimates of transpiration (T) in drylands, and (b) use this approach to evaluate how...
Authors
E.G. Reich, K. Samuels-Crow, John B. Bradford, M. Litvak, Daniel Rodolphe Schlaepfer, K. Ogle

Evaluating distributed snow model resolution and meteorology parameterizations against streamflow observations: Finer Is not always better Evaluating distributed snow model resolution and meteorology parameterizations against streamflow observations: Finer Is not always better

Estimating snow conditions is often done using numerical snowpack evolution models at spatial resolutions of 500 m and greater; however, snow depth in complex terrain often varies on sub-meter scales. This study investigated how the spatial distribution of simulated snow conditions varied across seven model spatial resolutions from 30 to 1,000 m and over two meteorological data sets...
Authors
Theodore B. Barnhart, Annie L. Putman, Aaron Joseph Heldmyer, David M. Rey, John C. Hammond, Jessica M. Driscoll, Graham A. Sexstone
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