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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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A new species of Helianthus (Asteracae) from Clark County, Nevada A new species of Helianthus (Asteracae) from Clark County, Nevada

Helianthus devernii T.M.Draper is described as a new endemic species from two small desert spring populations found within Red Rock Canyon National Conservation Area, Clark County, NV. Morphological data and nuclear ribosomal ITS marker data place it in section Ciliares series Pumili. Furthermore, the molecular data allies it most closely to H. pumilus Nutt. Helianthus devernii differs...
Authors
Trent M Draper, Todd Esque

Targeted and non-targeted analysis of young-of-year smallmouth bass using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry Targeted and non-targeted analysis of young-of-year smallmouth bass using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry

Smallmouth bass in the Susquehanna River Basin, Chesapeake Bay Watershed, USA, have been exhibiting clinical signs of disease and reproductive endocrine disruption (e.g., intersex, male plasma vitellogenin) for over fifteen years. Previous histological and targeted chemical analyses have identified infectious agents and pollutants in fish tissues including organic contaminants, mercury...
Authors
Paige Teehan, Megan K. Schall, Vicki S. Blazer, Frank L Dorman

Waterborne gradient Self-Potential (WaSP) logging in the Rio Grande to map localized and regional surface and groundwater exchanges across the Mesilla Valley Waterborne gradient Self-Potential (WaSP) logging in the Rio Grande to map localized and regional surface and groundwater exchanges across the Mesilla Valley

The Rio Grande is the primary source of recharge to the Mesilla Basin/Conejos-Médanos aquifer system (“Mesilla Basin aquifer system”) in the Mesilla Valley of New Mexico and Texas. The Mesilla Basin aquifer system is the primary source of water supply to several large cities along the United States–Mexico border. Identifying gaining and losing reaches of the Rio Grande in the Mesilla...
Authors
Scott Ikard, Andrew Teeple

Does earthquake stress drop increase with depth in the crust? Does earthquake stress drop increase with depth in the crust?

We combine earthquake spectra from multiple studies to investigate whether the increase in stress drop with depth often observed in the crust is real, or an artifact of decreasing attenuation (increasing Q) with depth. In many studies, empirical path and attenuation corrections are assumed to be independent of the earthquake source depth. We test this assumption by investigating whether...
Authors
Rachel E. Abercrombie, Daniel T. Trugman, Peter M. Shearer, Xiaowei Chen, Jiewen Zhang, Colin Nathanael Pennington, Jeanne L. Hardebeck, Thomas H W Goebel, Christine J Ruhl

Monthly river temperature trends across the US confound annual changes Monthly river temperature trends across the US confound annual changes

Climate variations and human modifications of the water cycle continue to alter the Earth's surface water and energy exchanges. It is therefore critical to ascertain how these changes impact water quality and aquatic ecosystem habitat metrics such as river temperatures. Though river temperature trend analyses exist in the literature, studies on seasonal trends in river temperatures...
Authors
Christa Kelleher, Heather E. Golden, Stacey A. Archfield

Forest resistance to extended drought enhanced by prescribed fire in low elevation forests of the Sierra Nevada Forest resistance to extended drought enhanced by prescribed fire in low elevation forests of the Sierra Nevada

Prescribed fire reduces fire hazards by removing dead and live fuels (small trees and shrubs). Reductions in forest density following prescribed fire treatments (often in concert with mechanical treatments) may also lessen competition so that residual trees might be more likely to survive when confronted with additional stressors, such as drought. The current evidence for these effects...
Authors
Phillip J. van Mantgem, Anthony C. Caprio, Nathan L. Stephenson, Adrian Das

Fish response to successive clearcuts in a second-growth forest from the central Coast range of Oregon Fish response to successive clearcuts in a second-growth forest from the central Coast range of Oregon

Research dating back to the 1950 s has documented negative effects from harvesting of primeval forests on stream ecosystems of the Pacific Northwest. By the early 1990 s, state and federal forest practice rules governing timber harvest were modified throughout North America to better protect aquatic habitats and biotic resources, principally salmonids. These rules inspired a generation...
Authors
D. S. Bateman, Nathan Chelgren, Robert E. Gresswell, Jason B. Dunham, David Hockman-Wert, D. W. Leer, K. D. Bladon

A preliminary regional geomorphologic map in Utopia Planitia of the Tianwen-1 Zhurong Landing Region A preliminary regional geomorphologic map in Utopia Planitia of the Tianwen-1 Zhurong Landing Region

A geomorphologic map is an important step to understanding the geologic context and history of a site; here, we present an initial geomorphologic map for an area spanning 22°–26°N, 108°–112°E in the Utopia Planitia (UP) region on Mars. This site is of special interest because it contains the May 2021 landing site of the Zhurong rover from Tianwen-1. Utopia Planitia exhibits many lobate...
Authors
Mackenzie M Mills, Alfred S. McEwen, Chris Okubo

A novel automatic phenology learning (APL) method of training sample selection using multiple datasets for time-series land cover mapping A novel automatic phenology learning (APL) method of training sample selection using multiple datasets for time-series land cover mapping

The long record of Landsat imagery, which is the cornerstone of Earth observation, provides an opportunity to monitor land use and land cover (LULC) change and understand the interactions between the climate and earth system through time. A few change detection algorithms such as Continuous Change Detection and Classification (CCDC) have been developed to utilize all available Landsat...
Authors
Congcong Li, George Z. Xian, Qiang Zhou, Bruce Pengra

The 6 May 1947 Milwaukee, Wisconsin, earthquake The 6 May 1947 Milwaukee, Wisconsin, earthquake

The State of Wisconsin is not known for earthquake activity. The authoritative public‐facing U.S. Geological Survey Comprehensive Catalog of earthquakes includes only three small (magnitude 2) earthquakes in the state, all instrumentally recorded. Although other catalogs include more events in Wisconsin, experience has shown that many types of events, such as explosions and cryoseisms...
Authors
Susan E. Hough

Could climate change benefit invasive snakes? Modelling the potential distribution of the California Kingsnake in the Canary Islands Could climate change benefit invasive snakes? Modelling the potential distribution of the California Kingsnake in the Canary Islands

The interaction between climate change and biological invasions is a global conservation challenge with major consequences for invasive species management. However, our understanding of this interaction has substantial knowledge gaps; this is particularly relevant for invasive snakes on islands because they can be a serious threat to island ecosystems. Here we evaluated the potential...
Authors
Julien C Piquet, Dan L Warren, Jorge Fernando Saavedra Bolanos, Jose Miguel Sanchez Rivero, Ramon Gallo-Barneto, Miguel Angel Cabrera-Perez, Robert N. Fisher, Sam R Fisher, Carlton J. Rochester, Brian Hinds, Manuel Nogales, Marta Lopez-Darias

Modeling moose habitat use by age, sex, and season in Vermont, USA using high-resolution lidar and national land cover data Modeling moose habitat use by age, sex, and season in Vermont, USA using high-resolution lidar and national land cover data

Moose (Alces alces) populations have experienced unprecedented declines along the southern periphery of their range, including Vermont, USA. Habitat management may be used to improve the status of the population and health of individuals. To date, however, Vermont wildlife managers have been challenged to effectively use this important tool due to the lack of fine-scale information on...
Authors
Joshua Blouin, Jacob Debow, Elias Rosenblatt, Cedric Alexander, Katherina Gieder, Nicholas Fortin, James Murdoch, Therese M. Donovan
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