Publications
USGS research activities relevant to Alaska have yielded more than 9400 historical publications. This page features some of the most recent newsworthy research findings.
Filter Total Items: 2875
Where land and sea meet: Brown bears and sea otters
In Katmai National Park, Alaska, USA, we have seen changes in the number of brown bears and sea otters. The number of animals of a species a habitat can support is called carrying capacity. Even though bears live on land and sea otters live in the ocean, these two mammals share coastal habitats. Bears eat salmon, other fish, plants, clams, and beached whales. Sea otters feed on clams and other mar
Authors
Heather Coletti, Grant Hilderbrand, James L. Bodkin, Brenda E. Ballachey, Joy Erlenbach, George G. Esslinger, Michael Hannam, Kimberly A. Kloecker, Buck Mangipane, Amy Miller, Daniel Monson, Benjamin Pister, K. Griffin, K. Bodkin, Tom Smith
Barrier islands influence the assimilation of terrestrial energy in nearshore fishes
We examined the relative importance of landscape features on estuarine fish trophic structure and dependence on terrestrial organic matter (OMterr) in four barrier island lagoon systems along the Alaskan Beaufort Sea coast. Our study compared two relatively large lagoon systems characterized by high river discharge and relatively free ocean water exchanges (central region near Prudhoe Bay, Alaska)
Authors
Ashley E. Stanek, Vanessa R. von Biela, Sarah M. Laske, Rebecca L. Taylor, Kenneth H. Dunton
Chemical geodynamics insights from a machine learning approach
The radiogenic isotope heterogeneity of oceanic basalts is often assessed using 2D isotope ratio diagrams. But because the underlying data are at least six dimensional (87Sr/86Sr, 143Nd/144Nd, 176Hf/177Hf, and 208,207,206Pb/204Pb), it is important to examine isotopic affinities in multi-dimensional data space. Here, we apply t-distributed stochastic neighbor embedding (t-SNE), a multi-variate stat
Authors
Andreas Stracke, M. Willig, F. Genske, P. Béguelin, Erin Todd
Biosiliceous, organic-rich, and phosphatic facies of Triassic strata of northwest Alaska: Transect across a high-latitude, low-angle continental margin
The Shublik Formation (Middle and Upper Triassic) is a mixed siliciclastic-carbonate-phosphatic unit in northern Alaska. It generated oil found in Prudhoe Bay and other accumulations and is a prospective self-sourced resource play on Alaska’s North Slope. Its distal, deeper-water equivalent—the Otuk Formation—consists largely of radiolarian chert, mudstone, and limestone and contains potential gas
Authors
Julie A. Dumoulin, Katherine J. Whidden, William A. Rouse, Richard O. Lease, Adam Boehlke, Paul O'Sullivan
Seismic sources in the aleutian cradle of tsunamis
No abstract available.
Authors
Robert C. Witter, Richard W. Briggs, Tina Dura, Simon E. Engelhart, Alan Nelson
Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics
Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet their energy needs. Here, we assessed whe
Authors
Karyn D. Rode, Brian D. Taras, Craig A. Stricker, Todd C. Atwood, Nicole P Boucher, George M. Durner, Andrew E. Derocher, Evan S. Richardson, Seth Cherry, Lori T. Quakenbush, Lara Horstmann, Jeffrey F. Bromaghin
Inventory of eelgrass (Zostera marina) and seaweeds at the end of the Alaska Peninsula, August–September 2012:
Coastal communities in Alaska are undergoing rapid environmental change from increasing temperatures and baseline data are needed to monitor potential impacts. We conducted the first surveys of the abundance and distribution of eelgrass (Zostera marina) and seaweeds in the western part of Izembek National Wildlife Refuge at the end of the Alaska Peninsula. Six embayments and two offshore islands w
Authors
David H. Ward, Kyle R. Hogrefe, Tyronne F. Donnelly, Neils C. Dau, Orville Lind, Kevin J. Payne, Sandra C. Lindstrom
Eelgrass (Zostera marina) and seaweed abundance along the coast of Nunivak Island, Yukon Delta National Wildlife Refuge, Alaska, 2010
Eelgrass (<em>Zostera marina</em>) is a highly productive seagrass that plays an essential role in the health of the estuarine and coastal ecosystems; however, information about its abundance and distribution is insufficient in the Bering Sea along the Yukon Delta National Wildlife Refuge. We inventoried the spatial extent and abundance of eelgrass and seaweed in Duchikthluk and Shoal bays on Nuni
Authors
David H. Ward, Kyle R. Hogrefe, Tyrone F. Donnelly, Lucretia L. Fairchild
Eelgrass (Zostera marina) and Seaweed Abundance along the Coast of Togiak National Wildlife Refuge, Alaska, 2008–10
We conducted a point-sampling survey to determine eelgrass (Zostera marina) and seaweed abundance in coastal waters adjacent to Togiak National Wildlife Refuge, Alaska, in July 2008–10. Eelgrass was known to be abundant in protected embayments of the southeastern Bering Sea and near the Togiak National Wildlife Refuge, but prior to this study, no systematic ground surveys had been conducted in the
Authors
David H. Ward, Kyle R. Hogrefe, Michael A. Swaim, Tyronne F. Donnelly, Lucretia L. Fairchild
Distribution of eelgrass (Zostera marina) in coastal waters adjacent to Togiak National Wildlife Refuge, Alaska
Declines in the distribution and abundance of seagrasses worldwide have prompted a need for baseline distribution maps of eelgrass (Zostera marina) in Alaska. We used high-resolution digital-color aerial photography and multi-spectral satellite imagery to map the distribution and spatial extent of eelgrass at 21 sites in coastal waters adjacent to Togiak National Wildlife Refuge (TNWR) in northwes
Authors
David H. Ward, Kyle R. Hogrefe, Tyronne F. Donnelly, Michael A. Swaim
Abundance and distribution of eelgrass (Zostera marina) and seaweeds at Izembek National Wildlife Refuge, Alaska, 2007–10
Eelgrass (Zostera marina) meadows are expansive along the lower Alaska Peninsula, supporting a rich diversity of marine life, yet little is known about their status and trends in the region. We tested techniques to inventory and monitor trends in the spatial extent and abundance of eelgrass in lagoons of the Izembek National Wildlife Refuge. We determined if Landsat imagery could be used to assess
Authors
David H. Ward, Kyle R. Hogrefe, Tyronne F. Donnelly, Lucretia L. Fairchild, Kristine M. Sowl, Sandra C. Lindstrom
Estimating Pacific walrus abundance and survival with multievent mark-recapture models
Arctic marine ecosystems are undergoing rapid physical and biological change associated with climate warming and loss of sea ice. Sea ice loss will impact many species through altered spatial and temporal availability of resources. In the Bering and Chukchi Seas, the Pacific walrus Odobenus rosmarus divergens is one species that could be impacted by rapid environmental change, and thus, population
Authors
William S. Beatty, Patrick R. Lemons, Jason P. Everett, Cara J. Lewis, Rebecca L. Taylor, Robert J. Lynn, Suresh A. Sethi, Lori T. Quakenbush, John J. Citta, Michelle Kissling, Natalia Kryukova, John K. Wennburg