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: 2891
Diverse juvenile life-history behaviours contribute to the spawning stock of an anadromous fish population
Habitat quality often varies substantially across space and time, producing a shifting mosaic of growth and mortality trade-offs across watersheds. Traditional studies of juvenile habitat use have emphasised the evolution of single optimal strategies that maximise recruitment to adulthood and eventual fitness. However, linking the distribution of individual behaviours that contribute to recruitmen
Authors
Timothy E. Walsworth, Daniel E. Schindler, Jennifer R. Griffiths, Christian E. Zimmerman
Reconnaissance investigation of the Lisburne Group in the Cobblestone Creek area, Chandler Lake quadrangle, Alaska
A reconnaissance investigation of the Carboniferous Lisburne Group in the Cobblestone Creek area, Chandler Lake Quadrangle, yields insights into its resource potential and regional relations. Locally porous vuggy dolostone with hydrocarbon reservoir potential occurs in the lower Lisburne in the three most southerly of five thrust sheets, and contains traces of dead oil in two of these sheets. The
Authors
Julie A. Dumoulin, Michael T. Whalen
Evidence for the assimilation of ancient glacier organic carbon in a proglacial stream food web
We used natural abundance δ13C, δ15N, and Δ14C to compare trophic linkages between potential carbon sources (leaf litter, epilithic biofilm, and particulate organic matter) and consumers (aquatic macroinvertebrates and fish) in a nonglacial stream and two reaches of the heavily glaciated Herbert River. We tested the hypothesis that proglacial stream food webs are sustained by organic carbon releas
Authors
Jason Fellman, Eran Hood, Peter A. Raymond, J.H. Hudson, Maura Bozeman, Mayumi L. Arimitsu
Polar bear population dynamics in the southern Beaufort Sea during a period of sea ice decline
In the southern Beaufort Sea of the United States and Canada, prior investigations have linked declines in summer sea ice to reduced physical condition, growth, and survival of polar bears (Ursus maritimus). Combined with projections of population decline due to continued climate warming and the ensuing loss of sea ice habitat, those findings contributed to the 2008 decision to list the species as
Authors
Jeffrey F. Bromaghin, Trent L. McDonald, Ian Stirling, Andrew E. Derocher, Evan S. Richardson, Eric V. Regehr, David C. Douglas, George M. Durner, Todd C. Atwood, Steven C. Amstrup
Observing a catastrophic thermokarst lake drainage in northern Alaska
The formation and drainage of thermokarst lakes have reshaped ice-rich permafrost lowlands in the Arctic throughout the Holocene. North of Teshekpuk Lake, on the Arctic Coastal Plain of northern Alaska, thermokarst lakes presently occupy 22.5% of the landscape, and drained thermokarst lake basins occupy 61.8%. Analysis of remotely sensed imagery indicates that nine lakes (>10 ha) have drained in t
Authors
Benjamin M. Jones, Christopher D. Arp
A review of infectious agents in polar bears (Ursus maritimus) and their long-term ecological relevance
Disease was a listing criterion for the polar bear (Ursus maritimus) as threatened under the Endangered Species Act in 2008; it is therefore important to evaluate the current state of knowledge and identify any information gaps pertaining to diseases in polar bears. We conducted a systematic literature review focused on infectious agents and associated health impacts identified in polar bears. Ove
Authors
Anna C. Fagre, Kelly A. Patyk, Pauline Nol, Todd C. Atwood, Karsten Hueffer, Colleen G. Duncan
Evaluating the status of individuals and populations: Advantages of multiple approaches and time scales
The assessment of population status is a central goal of applied wildlife research and essential to the field of wildlife conservation. “Population status” has a number of definitions, the most widely used having to do with the current trajectory of the population (i.e., growing, stable, or declining), or the probability of persistence (i.e., extinction risk), perhaps without any specific knowledg
Authors
Daniel H. Monson, Lizabeth Bowen
Unusually loud ambient noise in tidewater glacier fjords: a signal of ice melt
In glacierized fjords, the ice-ocean boundary is a physically and biologically dynamic environment that is sensitive to both glacier flow and ocean circulation. Ocean ambient noise offers insight into processes and change at the ice-ocean boundary. Here we characterize fjord ambient noise and show that the average noise levels are louder than nearly all measured natural oceanic environments (signi
Authors
Erin C. Pettit, Kevin M. Lee, Joel P. Brann, Jeffrey A. Nystuen, Preston S. Wilson, Shad O'Neel
Resilience and risk: a demographic model to inform conservation planning for polar bears
Climate change is having widespread ecological effects, including loss of Arctic sea ice. This has led to listing of the polar bear (Ursus maritimus) and other ice-dependent marine mammals under the U.S. Endangered Species Act (ESA). Methods are needed to evaluate the effects of climate change on population persistence to inform recovery planning for listed species. For polar bears, this includes
Authors
Eric V. Regehr, Ryan H. Wilson, Karyn D. Rode, Michael C. Runge
Life in the main channel: long-term hydrologic control of microbial mat abundance in McMurdo Dry Valley streams, Antarctica
Given alterations in global hydrologic regime, we examine the role of hydrology in regulating stream microbial mat abundance in the McMurdo Dry Valleys, Antarctica. Here, perennial mats persist as a desiccated crust until revived by summer streamflow, which varies inter-annually, and has increased since the 1990s. We predicted high flows to scour mats, and intra-seasonal drying to slow growth. Res
Authors
Tyler J. Kohler, Lee F. Stanish, Steven W. Crisp, Joshua C. Koch, Daniel Liptzin, Jenny L. Baeseman, Diane M. McKnight
Distance measures and optimization spaces in quantitative fatty acid signature analysis
Quantitative fatty acid signature analysis has become an important method of diet estimation in ecology, especially marine ecology. Controlled feeding trials to validate the method and estimate the calibration coefficients necessary to account for differential metabolism of individual fatty acids have been conducted with several species from diverse taxa. However, research into potential refinemen
Authors
Jeffrey F. Bromaghin, Karyn D. Rode, Suzanne M. Budge, Gregory W. Thiemann
Pre-fieldwork surveys
In sea-level studies, initial surveys at the office or library can increase a project’s likelihood of success. Pre-fieldwork surveys should begin with a thorough review of prior research literature that appraises available data, identifies data gaps, and places the project objectives into a broader scientific context. Whereas peer reviewed journal articles may contain a wealth of research findings
Authors
Robert C. Witter