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: 3091
Cenozoic tectono-thermal history of the Tordrillo Mountains, Alaska: Paleocene-Eocene ridge subduction, decreasing relief, and late Neogene faulting Cenozoic tectono-thermal history of the Tordrillo Mountains, Alaska: Paleocene-Eocene ridge subduction, decreasing relief, and late Neogene faulting
Topographic development inboard of the continental margin is a predicted response to ridge subduction. New thermochronology results from the western Alaska Range document ridge subduction related orogenesis. K-feldspar thermochronology (KFAT) of bedrock samples from the Tordrillo Mountains in the western Alaska Range complement existing U-Pb, 40Ar/39Ar and AFT (apatite fission track)...
Authors
Jeff A. Benowitz, Peter J. Haeussler, Paul W. Layer, Paul B. O'Sullivan, Wes K. Wallace, Robert J. Gillis
A multi-sensor lidar, multi-spectral and multi-angular approach for mapping canopy height in boreal forest regions A multi-sensor lidar, multi-spectral and multi-angular approach for mapping canopy height in boreal forest regions
Spatially explicit representations of vegetation canopy height over large regions are necessary for a wide variety of inventory, monitoring, and modeling activities. Although airborne lidar data has been successfully used to develop vegetation canopy height maps in many regions, for vast, sparsely populated regions such as the boreal forest biome, airborne lidar is not widely available...
Authors
David J. Selkowitz, Gordon Green, Birgit E. Peterson, Bruce Wylie
Effects of sea ice on winter site fidelity of Pacific common eiders (Somateria mollissima v-nigrum) Effects of sea ice on winter site fidelity of Pacific common eiders (Somateria mollissima v-nigrum)
In northern marine habitats, the presence or absence of sea ice results in variability in the distribution of many species and the quality and availability of pelagic winter habitat. To understand the effects of ice on intra- and inter-annual winter site fidelity and movements in a northern sea-duck species, we marked 25 adult Pacific Common Eiders (Somateria mollissima v-nigrum) on...
Authors
Margaret R. Petersen, David C. Douglas, Heather M. Wilson, Sarah E. McCloskey
Behavioral vs. molecular sources of conflict between nuclear and mitochondrial DNA: The role of male-biased dispersal in a Holarctic sea duck Behavioral vs. molecular sources of conflict between nuclear and mitochondrial DNA: The role of male-biased dispersal in a Holarctic sea duck
Genetic studies of waterfowl (Anatidae) have observed the full spectrum of mitochondrial (mt) DNA population divergence, from apparent panmixia to deep, reciprocally monophyletic lineages. Yet, these studies often found weak or no nuclear (nu) DNA structure, which was often attributed to male-biased gene flow, a common behaviour within this family. An alternative explanation for this...
Authors
Jeffrey L. Peters, Kimberly A. Bolender, John M. Pearce
Evidence of accelerated beak growth associated with avian keratin disorder in black-capped chickadees (Poecile atricapillus) Evidence of accelerated beak growth associated with avian keratin disorder in black-capped chickadees (Poecile atricapillus)
We recently documented an epizootic of beak deformities in more than 2,000 Black-capped Chickadees (Poecile atricapillus) and other wild bird species in North America. This emerging avian disease, which has been termed avian keratin disorder, results in gross overgrowth of the rhamphotheca, the outer, keratinized layer of the beak. To test the hypothesis that the beak deformities...
Authors
Caroline R. Van Hemert, Colleen M. Handel, Todd M. O'Hara
Bioenergetics model for estimating food requirements of female Pacific walruses (Odobenus rosmarus divergens) Bioenergetics model for estimating food requirements of female Pacific walruses (Odobenus rosmarus divergens)
Pacific walruses Odobenus rosmarus divergens use sea ice as a platform for resting, nursing, and accessing extensive benthic foraging grounds. The extent of summer sea ice in the Chukchi Sea has decreased substantially in recent decades, causing walruses to alter habitat use and activity patterns which could affect their energy requirements. We developed a bioenergetics model to estimate...
Authors
S.R. Noren, Mark S. Udevitz, C.V. Jay
Analysis of low-frequency seismic signals generated during a multiple-iceberg calving event at Jakobshavn Isbræ, Greenland Analysis of low-frequency seismic signals generated during a multiple-iceberg calving event at Jakobshavn Isbræ, Greenland
We investigated seismic signals generated during a large-scale, multiple iceberg calving event that occurred at Jakobshavn Isbræ, Greenland, on 21 August 2009. The event was recorded by a high-rate time-lapse camera and five broadband seismic stations located within a few hundred kilometers of the terminus. During the event two full-glacier-thickness icebergs calved from the grounded (or...
Authors
Fabian Walter, Jason M. Amundson, Shad O’Neel, Martin Truffer, Mark Fahnestock, Helen A. Fricker
Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change
Polar bears (PBs) are superbly adapted to the extreme Arctic environment and have become emblematic of the threat to biodiversity from global climate change. Their divergence from the lower-latitude brown bear provides a textbook example of rapid evolution of distinct phenotypes. However, limited mitochondrial and nuclear DNA evidence conflicts in the timing of PB origin as well as...
Authors
Webb Miller, Stephan C. Schuster, Andreanna J. Welch, Aakrosh Ratan, Oscar C. Bedoya-Reina, Fangqing Zhao, Hie Lim Kim, Richard C. Burhans, Daniela I. Drautz, Nicola E. Wittekindt, Lynn P. Tomsho, Enrique Ibarra-Laclette, Luis Herrera-Estrella, Elizabeth L. Peacock, Sean Farley, George K. Sage, Karyn D. Rode, Martyn E. Obbard, Rafael Montiel, Lutz Bachmann, Olafur Ingolfsson, Jon Aars, Thomas Mailund, Øystein Wiig, Sandra L. Talbot, Charlotte Lindqvist
Peat accumulation in drained thermokarst lake basins in continuous, ice-rich permafrost, northern Seward Peninsula, Alaska Peat accumulation in drained thermokarst lake basins in continuous, ice-rich permafrost, northern Seward Peninsula, Alaska
Thermokarst lakes and peat-accumulating drained lake basins cover a substantial portion of Arctic lowland landscapes, yet the role of thermokarst lake drainage and ensuing peat formation in landscape-scale carbon (C) budgets remains understudied. Here we use measurements of terrestrial peat thickness, bulk density, organic matter content, and basal radiocarbon age from permafrost cores...
Authors
Miriam C. Jones, Guido Grosse, Benjamin M. Jones, Katey Walter Anthony
Carry-over effects of winter location contribute to variation in timing of nest initiation and clutch size in black brant (Branta bernicla nigricans) Carry-over effects of winter location contribute to variation in timing of nest initiation and clutch size in black brant (Branta bernicla nigricans)
We assessed carry-over effects from winter location on timing of nest initiation and clutch size of Black Brant (Branta bernicla nigricans) using observations of individually marked brant breeding at the Tutakoke River colony in Alaska, and wintering along a latitudinal gradient at three areas on the Pacific coast of Baja California: northernmost Bahia San Quintin (BSQ), Laguna Ojo de...
Authors
Jason L. Schamber, James S. Sedinger, David H. Ward
Predicted eelgrass response to sea level rise and its availability to foraging Black Brant in Pacific coast estuaries Predicted eelgrass response to sea level rise and its availability to foraging Black Brant in Pacific coast estuaries
Managers need to predict how animals will respond to habitat redistributions caused by climate change. Our objective was to model the effects of sea level rise on total eelgrass (Zostera marina) habitat area and on the amount of that area that is accessible to Brant geese (Branta bernicla), specialist grazers of eelgrass. Digital elevation models were developed for seven estuaries from...
Authors
Frank J. Shaughnessy, Whelan Gilkerson, Jeffrey M. Black, David H. Ward, Mark Petrie
Phenology and duration of remigial moult in Surf Scoters (Melanitta perspicillata) and White-winged Scoters (Melanitta fusca) on the Pacific coast of North America Phenology and duration of remigial moult in Surf Scoters (Melanitta perspicillata) and White-winged Scoters (Melanitta fusca) on the Pacific coast of North America
By quantifying phenology and duration of remigial moult in Surf Scoters (Melanitta perspicillata (L., 1758)) and White-winged Scoters (Melanitta fusca (L., 1758)), we tested whether timing of moult is dictated by temporal optima or constraints. Scoters (n = 3481) were captured during moult in Alaska, British Columbia, and Washington, and remigial emergence dates were determined. We...
Authors
Rian D. Dickson, Daniel Esler, Jerry W. Hupp, E.M. Anderson, J.R. Evenson, J. Barrett