Determination and uncertainty of moment tensors for microearthquakes at Okmok Volcano, Alaska
J. D. Pesicek, J. Sileny, S. G. Prejean, C.H. Thurber
2012, Geophysical Journal International (190) 1689-1709
Efforts to determine general moment tensors (MTs) for microearthquakes in volcanic areas are often hampered by small seismic networks, which can lead to poorly constrained hypocentres and inadequate modelling of seismic velocity heterogeneity. In addition, noisy seismic signals can make it difficult to identify phase arrivals correctly for small magnitude...
Synchronous cycling of Ichthyophoniasis with Chinook salmon density revealed during the annual Yukon River spawning migration
Stanley Zuray, Richard Kocan, Paul Hershberger
2012, Transactions of the American Fisheries Society (141) 615-623
Populations of Chinook salmon Oncorhynchus tshawytscha in the Yukon River declined by more than 57% between 2003 and 2010, probably the result of a combination of anthropogenic and environmental factors. One possible contributor to this decline is Ichthyophonus, a mesomycetozoan parasite that has previously been implicated in significant losses of...
Detecting hidden volcanic explosions from Mt. Cleveland Volcano, Alaska with infrasound and ground-couples airwaves
Slivio De Angelis, David Fee, Matthew Haney, David Schneider
2012, Geophysical Research Letters (39)
In Alaska, where many active volcanoes exist without ground-based instrumentation, the use of techniques suitable for distant monitoring is pivotal. In this study we report regional-scale seismic and infrasound observations of volcanic activity at Mt. Cleveland between December 2011 and August 2012. During this period, twenty explosions were detected by...
Spatial genetic structure and asymmetrical gene flow within the Pacific walrus
Sarah A. Sonsthagen, Chadwick V. Jay, Anthony S. Fischbach, George K. Sage, Sandra L. Talbot
2012, Journal of Mammalogy (93) 1512-1524
Pacific walruses (Odobenus rosmarus divergens) occupying shelf waters of Pacific Arctic seas migrate during spring and summer from 3 breeding areas in the Bering Sea to form sexually segregated nonbreeding aggregations. We assessed genetic relationships among 2 putative breeding populations and 6 nonbreeding aggregations. Analyses of mitochondrial DNA (mtDNA) control...
Canada Basin revealed
David C. Mosher, John Shimeld, Deborah R. Hutchinson, D Chian, Nina Lebedeva-Ivanova, Ruth Jackson
2012, Conference Paper, Arctic Technology Conference: Challenges for today, opportunities for tomorrow
More than 15,000 line-km of new regional seismic reflection and refraction data in the western Arctic Ocean provide insights into the tectonic and sedimentologic history of Canada Basin, permitting development of new geologic understanding in one of Earth's last frontiers. These new data support a rotational opening model for southern...
Walrus distributional and foraging response to changing ice and benthic conditions in the Chukchi Sea
Chadwick V. Jay, Jacqueline M. Grebmeier, Anthony S. Fischbach
2012, North Pacific Research Board Project Final Report 818
Arctic species such as the Pacific walrus (Odobenus rosmarus divergens) are facing a rapidly changing environment. Walruses are benthic foragers and may shift their spatial patterns of foraging in response to changes in prey distribution. We used data from satellite radio-tags attached to walruses in 2009-2010 to map walrus foraging...
Biodegradability of dissolved organic carbon in the Yukon River and its tributaries: Seasonality and importance of inorganic nitrogen
Kimberly P. Wickland, George R. Aiken, Kenna D. Butler, Mark M. Dornblaser, RGM Spencer, Robert G. Striegl
2012, Global Biogeochemical Cycles (26) 1-14
Northern high-latitude rivers transport large amounts of terrestrially derived dissolved organic matter (DOM) from boreal and arctic ecosystems to coastal areas and oceans. Current knowledge of the biodegradability of DOM in these rivers is limited, particularly for large rivers discharging to the Arctic Ocean. We conducted a seasonally comprehensive study...
Assessment of boreal forest historical C dynamics in the Yukon River Basin: relative roles of warming and fire regime change
F.M. Yuan, S.H. Yi, A. D. McGuire, K.D. Johnson, J. Liang, J.W. Harden, E.S. Kasischke, W.A. Kurz
2012, Ecological Applications (22) 2091-2109
Carbon (C) dynamics of boreal forest ecosystems have substantial implications for efforts to mitigate the rise of atmospheric CO2 and may be substantially influenced by warming and changing wildfire regimes. In this study we applied a large-scale ecosystem model that included dynamics of organic soil horizons and soil organic matter...
Identifying potential habitat for the endangered Aleutian shield fern using topographical characteristics
Adam Duarte, Daniel M. Wolcott, T. Edwin Ricca Chow Ricca, Mark A.
2012, Journal of Fish and Wildlife Management (3) 303-310
The Aleutian shield fern Polystichum aleuticum is endemic to the Aleutian archipelago of Alaska and is listed as endangered pursuant to the U.S. Endangered Species Act. Despite numerous efforts to discover new populations of this species, only four known populations are documented to date, and information is needed to prioritize...
Using surface velocities to calculate ice thickness and bed topography: A case study at Columbia Glacier, Alaska, USA
R.W. McNabb, R. Hock, Shad O’Neel, Lowell A. Rasmussen, Y. Ahn, M. Braun, H. Conway, S. Herreid, I. Joughin, W.T. Pfeffer, B.E. Smith, M. Truffer
2012, Journal of Glaciology (58) 1151-1164
Information about glacier volume and ice thickness distribution is essential for many glaciological applications, but direct measurements of ice thickness can be difficult and costly. We present a new method that calculates ice thickness via an estimate of ice flux. We solve the familiar continuity equation between adjacent flowlines, which...
High shrew diversity on Alaska's Seward Peninsula: Community assembly and environmental change
Andrew G. Hope
2012, Northwestern Naturalist (93) 101-110
In September 2010, 6 species of shrews (genus: Sorex) were collected at a single locality on the Seward Peninsula of Alaska. Such high sympatric diversity within a single mammalian genus is seldom realized. This phenomenon at high latitudes highlights complex Arctic community dynamics that reflect significant turnover through time as...
Spawning salmon and the fitness of stream-dwelling fishes: Marine-derived nutrients show saturating effects on growth and energy storage in juvenile salmonids
D.J. Rinella, M.S. Wipfli, C. A. Stricker, R. Heintz
2012, Canadian Journal of Fisheries and Aquatic Sciences (69) 73-84
We examined how marine-derived nutrients (MDN), in the form of spawning Pacific salmon, influenced the nutritional status and d15N of stream-dwelling fishes. We sampled juvenile coho salmon (Oncorhynchus kisutch) and Dolly Varden (Salvelinus malma) during spring and fall from 11 south-central Alaskan streams that ranged widely in spawning salmon biomass...
Chronic hydrocarbon exposure of harlequin ducks in areas affected by the Selendang Ayu oil spill at Unalaska Island, Alaska
Paul L. Flint, J.L. Schamber, K.A. Trust, A.K. Miles, J.D. Henderson, B.W. Wilson
2012, Environmental Toxicology and Chemistry (31) 2828-2831
We evaluated chronic exposure of harlequin ducks (Histrionicus histrionicus) to hydrocarbons associated with the 2004 M/V Selendang Ayu oil spill at Unalaska Island, Alaska. We measured levels of hepatic 7-ethoxyresorufin-O-deethylase activity (EROD) in liver biopsy samples as an indicator of hydrocarbon exposure in three oiled bays and one reference bay in...
Moderating Argos location errors in animal tracking data
David C. Douglas, Rolf Weinziert, Sarah C. Davidson, Roland Kays, Martin Wikelski, Gil Bohrer
2012, Methods in Ecology and Evolution (3) 999-1007
1. The Argos System is used worldwide to satellite-track free-ranging animals, but location errors can range from tens of metres to hundreds of kilometres. Low-quality locations (Argos classes A, 0, B and Z) dominate animal tracking data. Standard-quality animal tracking locations (Argos classes 3, 2 and 1) have larger errors...
Listening to Glaciers: Passive hydroacoustics near marine-terminating glaciers
E.C. Pettit, J.A. Nystuen, Shad O’Neel
2012, Oceanography (25) 104-105
The catastrophic breakup of the Larsen B Ice Shelf in the Weddell Sea in 2002 paints a vivid portrait of the effects of glacier-climate interactions. This event, along with other unexpected episodes of rapid mass loss from marine-terminating glaciers (i.e., tidewater glaciers, outlet glaciers, ice streams, ice shelves) sparked intensified...
Food availability and offspring sex in a monogamous seabird: insights from an experimental approach
Thomas Merkling, Sarah Leclaire, Etienne Danchin, Emeline Lhuillier, Richard H. Wagner, Joel White, Scott A. Hatch, Pierrick Blanchard
2012, Behavioral Ecology (23) 751-758
Sex allocation theory predicts that parents should favor offspring of the sex that provides the greatest fitness return. Despite growing evidence suggesting that vertebrates are able to overcome the constraint of chromosomal sex determination, the general pattern remains equivocal, indicating a need for experimental investigations. We used an experimental feeding...
Vegetation shifts observed in arctic tundra 17 years after fire
Kirsten Barrett, Adrian V. Rocha, Martine Janet van de Weg, Gaius Shaver
2012, Remote Sensing Letters (3) 729-736
With anticipated climate change, tundra fires are expected to occur more frequently in the future, but data on the long-term effects of fire on tundra vegetation composition are scarce. This study addresses changes in vegetation structure that have persisted for 17 years after a tundra fire on the North Slope...
A simple method for in situ monitoring of water temperature in substrates used by spawning salmonids
Christian E. Zimmerman, James E. Finn
2012, Journal of Fish and Wildlife Management (3) 288-295
Interstitial water temperature within spawning habitats of salmonids may differ from surface-water temperature depending on intragravel flow paths, geomorphic setting, or presence of groundwater. Because survival and developmental timing of salmon are partly controlled by temperature, monitoring temperature within gravels used by spawning salmonids is required to adequately describe the...
Rapid movement of frozen debris-lobes: implications for permafrost degradation and slope instability in the south-central Brooks Range, Alaska
R.P. Daanen, G. Grosse, M.M. Darrow, T. D. Hamilton, Benjamin M. Jones
2012, Natural Hazards and Earth System Sciences (12) 1521-1537
We present the results of a reconnaissance investigation of unusual debris mass-movement features on permafrost slopes that pose a potential infrastructure hazard in the south-central Brooks Range, Alaska. For the purpose of this paper, we describe these features as frozen debris-lobes. We focus on the characterisation of frozen debris-lobes as...
Molecular detection of hematozoa infections in tundra swans relative to migration patterns and ecological conditions at breeding grounds
Andrew M. Ramey, Craig R. Ely, Joel A. Schmutz, John M. Pearce, Darryl J. Heard
2012, PLoS ONE (7)
Tundra swans (Cygnus columbianus) are broadly distributed in North America, use a wide variety of habitats, and exhibit diverse migration strategies. We investigated patterns of hematozoa infection in three populations of tundra swans that breed in Alaska using satellite tracking to infer host movement and molecular techniques to assess the...
Structure of marine predator and prey communities along environmental gradients in a glaciated fjord
Martin Renner, Mayumi L. Arimitsu, John F. Piatt
2012, Canadian Journal of Fisheries and Aquatic Sciences (69) 2029-2045
Spatial patterns of marine predator communities are influenced to varying degrees by prey distribution and environmental gradients. We examined physical and biological attributes of an estuarine fjord with strong glacier influence to determine the factors that most influence the structure of predator and prey communities. Our results suggest that some...
Evidence of accelerated beak growth associated with avian keratin disorder in black-capped chickadees (Poecile atricapillus)
Caroline R. Van Hemert, Colleen M. Handel, Todd M. O'Hara
2012, Journal of Wildlife Diseases (48) 686-694
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...
Characterizing post-drainage succession in Thermokarst Lake Basins on the Seward Peninsula, Alaska with TerraSAR-X Backscatter and Landsat-based NDVI data
Prajna Regmi, Guido Grosse, Miriam C. Jones, Benjamin M. Jones, Katey Walter Anthony
2012, Remote Sensing (4) 3741-3765
Drained thermokarst lake basins accumulate significant amounts of soil organic carbon in the form of peat, which is of interest to understanding carbon cycling and climate change feedbacks associated with thermokarst in the Arctic. Remote sensing is a tool useful for understanding temporal and spatial dynamics of drained basins. In...
Bioenergetics model for estimating food requirements of female Pacific walruses (Odobenus rosmarus divergens)
S.R. Noren, Mark S. Udevitz, C.V. Jay
2012, Marine Ecology Progress Series (460) 261-275
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...
Cenozoic tectono-thermal history of the Tordrillo Mountains, Alaska: Paleocene-Eocene ridge subduction, decreasing relief, and late Neogene faulting
Jeff A. Benowitz, Peter J. Haeussler, Paul W. Layer, Paul B. O'Sullivan, Wes K. Wallace, Robert J. Gillis
2012, Geochemistry, Geophysics, Geosystems (13)
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)...
