• Geometry and kinematics of the Yakataga anticline, Icy Bay, Alaska

      Broadwell, Michael Scott; Wallace, Wes; McCarthy, Paul; Hanks, Cathy (2001-05)
      The Yakataga incline is a well-exposed asymmetrical fold with a ramp tip beneath the forelimb. Uncomformities in the backlimb and forelimb indicate that both limbs rotated during fold growth. The stratigraphic character and evidence for deformation before full lithification suggest non-parallel folding by distributed strain rather than flexural slip. These characteristics of the natural fold do not fit existing models for thrust-related folds and I suggest two models for the Yakataga anticline's growth: 1) the fold formed as a non-parallel detachment fold modified by fault-propagation folding in the forelimb; and 2) the fold formed as a rotating-limb fault-propagation fold. The first of these models seems to fit the natural fold better because: 1) this model accounts for the subsidiary fold in the forelimb; and 2) rotation of the backlimb in the fault-propagation fold model requires a fanning of the bedding, a feature not observed in the natural fold.
    • Geometry and kinematics of thrust-truncated and/or flattened asymmetrical folds in the eastern Brooks Range, Alaska

      Bailey, Rebecca D. (2007-08)
      Exceptional exposures of thrust-related folds within carbonate rocks of the Lisburne Group of the Brooks Range of northern Alaska are classified into four groups: unbroken/parallel folds, thrust-truncated/parallel folds, unbroken/flattened folds and thrust-truncated/flattened folds. The geometry of these folds varies greatly along strike, suggesting that serial sections do not represent successive stages in fold evolution. Geometric and kinematic modeling of individual folds reveals that no single fault-related fold model can reproduce the geometry of a given fold. Instead, successful forward modeling of the folds requires some combination of detachment folding with fault-bend folding or fault-propagation folding. All folds followed one of two kinematic paths: the initially parallel folds either broke through without flattening or flattened first and then broke through. Preferred hypothesis for why folds would deform by one path verses the other include: I) Original asymmetry will promote breakthrough over flattening, so that originally asymmetric folds will break through without flattening while initially symmetric folds will flatten before breaking through; and 2) A thin detachment unit may limit fold growth resulting in breakthrough without flattening, while a thick detachment units will not limit fold growth, allowing folds to shorten via flattening before breaking through.
    • The geometry in geometric algebra

      Kilpatrick, Kristopher N.; Maxwell, David A.; Williams, Gordon I.; Rhodes, John A. (2014-12)
      We present an axiomatic development of geometric algebra. One may think of a geometric algebra as allowing one to add and multiply subspaces of a vector space. Properties of the geometric product are proven and derived products called the wedge and contraction product are introduced. Linear algebraic and geometric concepts such as linear independence and orthogonality may be expressed through the above derived products. Some examples with geometric algebra are then given.
    • A geostatistical model based on Brownian motion to Krige regions in R2 with irregular boundaries and holes

      Bernard, Jordy; McIntyre, Julie; Barry, Ron; Goddard, Scott (2019-05)
      Kriging is a geostatistical interpolation method that produces predictions and prediction intervals. Classical kriging models use Euclidean (straight line) distance when modeling spatial autocorrelation. However, for estuaries, inlets, and bays, shortest-in-water distance may capture the system’s proximity dependencies better than Euclidean distance when boundary constraints are present. Shortest-in-water distance has been used to krige such regions (Little et al., 1997; Rathbun, 1998); however, the variance-covariance matrices used in these models have not been shown to be mathematically valid. In this project, a new kriging model is developed for irregularly shaped regions in R 2 . This model incorporates the notion of flow connected distance into a valid variance-covariance matrix through the use of a random walk on a lattice, process convolutions, and the non-stationary kriging equations. The model developed in this paper is compared to existing methods of spatial prediction over irregularly shaped regions using water quality data from Puget Sound.
    • Glacier contribution to lowland streamflow: a multi-year, geochemical hydrograph separation study in sub-Arctic Alaska

      Gatesman, Tiffany A.; Trainor, Thomas P.; Liljedahl, Anna K.; Douglas, Thomas A. (2017-12)
      Glacier melt affects the geochemical composition of rivers; however, quantifying the glacier contribution to subarctic watershed-scale runoff has attracted limited attention. To estimate glacier contribution, we conducted a 6-year geochemical hydrograph separation study in a geologically heterogeneous glacierized watershed in Interior Alaska. Water samples were collected daily from Jarvis Creek during late April through September. Source waters were collected synoptically each year from rain, snow, baseflow (winter discharge), and the glacier terminus discharge. All samples were analyzed for stable water isotopes and dissolved ion concentrations. Stream surface water samples have large seasonal and inter-annual geochemical variation, however, source waters show distinct chemical signatures allowing the application of a geochemical hydrograph separation model to quantify relative source contribution to lowland streamflow. Considerable inter-annual differences within source water signatures emphasize the importance in informing the model with source waters sampled for each season. We estimated a seasonal average of 35% (20 to 44%) glacier terminus discharge contribution with a daily range of 2 (May) to 80% (September). If glacier contribution was to cease completely, stream discharge would be reduced by 48% and 22% in low and high rainfall summers, respectively. Combined with the documented shrinkage of glaciers, our findings emphasizes the need for further research on glacial wastage effect on subarctic watersheds.
    • Global and local contributors to the historical and projected regional climate change on the North Slope of Alaska

      Cai, Lei; Alexeev, Vladimir A.; Arp, Christopher D.; Bhatt, Uma S.; Liljedahl, Anna K. (2018-05)
      This thesis includes four studies that explore and compare the impacts of four contributing factors resulting in regional climate change on the North Slope of Alaska based on a numerical simulation approach. These four contributing factors include global warming due to changes in radiative forcing, sea ice decline, earlier Arctic lake ice-off, and atmospheric circulation change over the Arctic. A set of dynamically downscaled regional climate products has been developed for the North Slope of Alaska over the period from 1950 up to 2100. A fine grid spacing (10 km) is employed to develop products that resolve detailed mesoscale features in the temperature and precipitation fields on the North Slope of Alaska. Processes resolved include the effects of topography on regional climate and extreme precipitation events. The Representative Concentration Pathway (RCP) 4.5 scenario projects lower rates of precipitation and temperature increase than RCP8.5 compared to the historical product. The increases of precipitation and temperature trends in the RCP8.5 projection are higher in fall and winter compared to the historical product and the RCP4.5 projection. The impacts of sea ice decline are addressed by conducting sensitivity experiments employing both an atmospheric model and a permafrost model. The sea ice decline impacts are most pronounced in late fall and early winter. The near surface atmospheric warming in late spring and early summer due to sea ice decline are projected to be stronger in the 21st century. Such a warming effect also reduces the total cloud cover on the North Slope of Alaska in summer by destabilizing the atmospheric boundary layer. The sea ice decline warms the atmosphere and the permafrost on the North Slope of Alaska less strongly than the global warming does, while it primarily results in higher seasonal variability of the positive temperature trend that is bigger in late fall and early winter than in other seasons. The ongoing and projected earlier melt of the Arctic lake ice also contributes to regional climate change on the Northern coast of Alaska, though only on a local and seasonal scale. Heat and moisture released from the opened lake surface primarily propagate downwind of the lakes. The impacts of the earlier lake ice-off on both the atmosphere and the permafrost underneath are comparable to those of the sea ice decline in late spring and early summer, while they are roughly six times weaker than those of sea ice decline in late fall and early winter. The permafrost warming resulted from the earlier lake ice-off is speculated to be stronger with more snowfall expected in the 21st century, while the overall atmospheric warming of global origin is speculated to continue growing. Two major Arctic summer-time climatic variability patterns, the Arctic Oscillation (AO) and the Arctic Dipole (AD), are evaluated in 12 global climate models in Coupled Model Intercomparison Program Phase 5 (CMIP5). A combined metric ranking approach ranks the models by the Pattern Correlation Coefficients (PCCs) and explained variances calculated from the model-produced summer AO and AD over the historical period. Higher-ranked models more consistently project a positive trend of the summer AO index and a negative trend of summer AD index in their RCP8.5 projections. Such long-term trends of large-scale climate patterns will inhibit the increase in air temperature while favoring the increase in precipitation on the North Slope of Alaska. In summary, this thesis bridges the gaps by quantifying the relative importance of multiple contributing factors to the regional climate change on the North Slope of Alaska. Global warming is the leading contributing factor, while other factors primarily contribute to the spatial and temporal asymmetries of the regional climate change. The results of this thesis lead to a better understanding of the physical mechanisms behind the climatic impacts to the hydrological and ecological changes of the North Slope of Alaska that have been become more severe and more frequent. They, together with the developed downscaling data products, serve as the climatic background information in such fields of study.
    • Glucose transporter-4 in mononuclear cells of sled dogs

      Schnurr, Theresia Maria; Dunlap, Kriya; Reynolds, Arleigh; Duffy, Lawrence (2013-12)
      The glucose transporter-4 (GLUT4) is the glucose transporter most responsive to insulin and has been thought to exist predominately in muscle and adipose cells. There have been findings that the glucose transporter-4 isoform is also expressed in subpopulations of white blood cells such as mononuclear cells. This study was designed to validate the presence of GLUT4 in subpopulations of white blood cells of sled dogs and to investigate whether changes in GLUT4 protein levels in white blood cells might be associated with age and stage of conditioning, as it has been reported in muscle. Our initial results have shown the ability to detect GLUT4 in white blood cells of sled dogs with a non-significant trend observed in GLUT4 levels based on age. Subsequent testing showed a statistically significant difference in GLUT4 levels in mononuclear cells based on conditioning in sled dogs. Using sled dogs as a model should enhance our understanding of GLUT4 expression on the surface of subpopulations of white blood cells. The presented projects are groundbreaking for the development of an easy, reliable and minimally invasive diagnostic tool for insulin sensitivity. Our next step in this research is to examine whether the conditioning response of GLUT4 is also observed in human mononuclear cells.
    • Glucose transporter-4 on peripheral blood mononuclear cells in conditioned vs. sedentary college students

      Sticka, Kendra D.; Knall, Cindy M.; Dunlap, Kriya L.; Krebs, Jocelyn E.; Duffy, Lawrence K. (2016-05)
      Glucose transporter 4 (GLUT-4) plays a key role in the pathophysiology of type 2 diabetes. GLUT-4 is upregulated in response to exercise, enhancing cellular glucose transport in skeletal muscle tissue. This mechanism appears to remain intact in individuals with insulin resistance. There is evidence of increased translocation of GLUT-4 and increased transcription of SLC2A, the gene which codes for GLUT-4. Details of the mechanism are poorly understood and are challenging to study due to the invasive nature of muscle biopsy. Peripheral blood mononuclear cells (PBMC) have documented insulin-sensitive GLUT-4 activity and may serve as a proxy tissue for studying skeletal muscle GLUT-4. The purpose of this study was to investigate whether GLUT-4 on PBMC is affected by exercise in a similar fashion to myocytes. Additionally, correlations between PBMC GLUT-4 and common indicators of insulin resistance and dietary patterns were examined. The results show a trend toward higher PBMC GLUT-4 levels in conditioned athletes than in their sedentary counterparts, similar to what has been documented in myocytes. Females were shown to have higher PBMC GLUT-4 levels than males. SLC2A4 mRNA analysis demonstrates a difference in mean gene expression between the conditioned and sedentary participants. Correlations between levels of PBMC GLUT-4 and hemoglobin A1c (HbA1c), glucose, insulin, HOMA-IR, BMI, or body fat were not detected. Relationships between specific nutrients and GLUT-4 were also not detected. This study provides evidence to support exploration of PBMC as a proxy tissue for studying GLUT-4 response to exercise or other non-insulin factors. This could provide important treatment avenues for individuals with insulin resistance and type 2 diabetes.
    • Gold and base metal mineralization of the Dolphin intrusion-related gold deposit, Fairbanks Mining District, Alaska

      Raymond, Luke M.; Newberry, Rainer; Larsen, Jessica; Keskinen, Mary (2018-08)
      The Dolphin deposit is an intrusion-related gold deposit (IRGD) located approximately 30 km north of Fairbanks, Alaska. The deposit is in--and adjacent to--a composite mid-Cretaceous pluton intruding amphibolite facies metamorphic rocks. An NI43-101 compliant gold resource estimation for the deposit (utilizing a 0.3 g/t cut-off grade) is 61.5 Million tonnes (Mt) at 0.69 g/t indicated (1.36 million oz = Moz) and 71.5 Mt at 0.69 g/t inferred (1.58 Moz). Due to extensive hydrothermal alteration of the intrusion, identifying rock types in hand sample and thin section, as well as by standard compositional techniques (e.g., SiO₂ vs. Na₂O + K₂O), has proven problematic. By plotting wt % TiO₂ vs. P₂O5 obtained from XRF analyses and four-acid digest ICP-MS data, two distinct population clusters appear. By comparison with least-altered intrusive rock analyses from the Fairbanks district, the igneous units were originally granite and tonalite. Because there is no gradational transition through an intermediate granodiorite unit, they were most likely derived from two separate magmatic bodies rather than in-situ fractionation from a single parent. Tonalite is concentrated along the northern and eastern margins of the stock with granite composing the rest of the body. Tonalite xenoliths in granite and granite dikes intruding tonalite prove that tonalite is the older unit. Investigations of hydrothermal alteration (based on chemical analyses, X-ray diffraction, and thin section examination) show albitic and advanced argillic (kaolinite-quartz) alteration are the dominant styles with sericite common throughout. Advanced argillic is a low temperature (<300°C) low pH alteration style that has not been previously identified in intrusion related gold deposits (IRGDs) in interior Alaska. Albitic alteration probably resulted from higher temperature, more neutral pH fluids. Gold investigations show that gold occurs as coarse-grained Au°, aurostibite, and maldonite in quartz + sulfide veins; fine-grained Au° in the oxide zone; and in many forms in disseminated sulfide. These forms include Au° inclusions in pyrite and arsenopyrite; solid-solution Au within compositionally zoned arsenopyrite; and as Au° nanoparticles in pyrite and probably arsenopyrite. Using UAF's JEOL JXA-8530F microprobe, I found that solid-solution gold occurs only in arsenopyrite with strong compositional zoning. Such grains are always small (< 0.2 mm) and commonly have low As cores; gold- bearing mantles with moderate % As; and higher As rims. In contrast, compositionally homogenous arsenopyrite does not contain detectable solid-solution gold. Pyrite is commonly arsenian and carries dissolved gold (if any) near detection limits. Gold mineralization has not been tied to any one lithology or alteration style; however, gold does seem to correlate with abrupt changes in alteration, especially between sericite + albite and kaolinite + sericite alteration. Gold-bearing, zoned arsenopyrite is predominantly associated with advanced argillic alteration and apparently represents a rapid growth, disequilibrium phenomenon.
    • GPS based tectonic analysis of the Aleutian arc and Bering plate

      Cross, Ryan S. (2007-05)
      Global Positioning System (GPS) measurements enable a quantitative analysis of tectonic deformation in the Aleutian Islands, Alaska. We construct elastic deformation models to calculate coupling on the subduction interface and the interseismic strain recorded at stations throughout the Aleutian arc. Using a grid-search inversion procedure, we determine an arc translation velocity for each region of the arc, revealing south to southwest motions of 4 to 14 mm/yr. In the central Aleutians, there is good agreement between areas of high coupling and areas of large moment release in major seismogenic events. We have combined modeling results from the Aleutians with direct measurements of station velocities of sites in western Alaska and the Bering Sea islands to test the hypothesis of a clockwise rotating Bering plate. The Bering Sea area including the Aleutian arc and western Alaska is fit by an Euler pole located at 42.5°N, 121.3°E with an angular velocity of 6.0°/my, relative to stable North America. The Bering plate's eastern boundary appears to be related to left lateral faulting in interior Alaska as clockwise rotation of the plate results in south-southwest motion relative to the North American plate. The Bering plate's interaction with a counter-clockwise rotating southcentral Alaska block may be responsible for the decreased slip-rate on the western Denali fault. Thrust earthquake slip azimuths expose a systematic discrepancy with Pacific-Bering plate convergence direction. A simple model of slip partitioning and GPS measurements reveal that slip partitioning is present in the forearc throughout the arc but only develops in the back arc west of Amchitka Pass.
    • GRID habitat plot survey data for the nesting sea turtles beach La Flor beach, Pacific, southwestern Nicaragua July of 2013

      Huettmann, Falk (Maderas Rainforest Conservancy, 2013-07-29)
      This GRID habitat plot survey was done at a globally relevant sea turtle nesting beach: La Flor (latitude 11.14282, longitude 85.79418, geographic datum WGS84). This sand beach is located at the Pacific Ocean in southwestern Nicaragua, approx. 20 km far from San Juan Del Sur and approx. 30 km far from the Costa Rican border. We did our grid-based habitat survey on the 11th of July in 2013. The GRID points are geo-referenced by latitude and longitude (decimal degrees, WGS84, +- 10 meters acuracy) and were visited only once (no 3 repeats were done because it consists of sand and private/reserve property) and no species information is provided (sand beach). From 25 regular GRID points 13 were inaccessable because of reserve land holdings or dense bush forests. We took three photos (sky, ground vertical view) for every plot, more details can be seen there. This grid can be used for change detection, shoreline location, develeopment questions, and beach erosion questions over time for turtle nest habitat, for instance. Known sea turtles for this region are predominately Olive`s Ridley sea turtle (Lepidochelys olivacea, TSN 173840), but also Hawksbill (Eretmochelys imbricata TSN 208666) and Leatherback sea turtle (Dermochelys coriacea, TSN 173843).
    • GRID survey habitat data for Playa el Coco beach (nesting sea turtles) - Pacific, southwestern Nicaragua July of 2013

      Huettmann, Falk (Maderas Rainforest Conservancy, 2013-07-29)
      This GRID survey was done at the beach of Playa de Coco - near a globally relevant sea turtle nesting beach (La Flor). Playa el Coco (latitude 11.15382, longitude 85.80051, geographic datum WGS84) is situated at the Pacific Ocean in southwestern Nicaragua, approx. 20 km far from San Juan Del Sur and approx. 30 km far from the Costa Rican border, just adjacent to La Flor. We did our grid-based habitat survey on 8th and 9th of July in 2013. The GRID points are geo-referenced by latitude and longitude (decimal degrees, WGS84, +- 10 meters acuracy) and were visited only once (no 3 repeats because it consists of sand and private property) and no species information (mostly empty sand beach). From 25 regular GRID points 9 were inaccessable because of private land holdings or very bushy forests. We took photos for every point (horizontal, vertical, sky), more details can be seen there. This grid can be used for change detection, shoreline location, develeopment, and beach erosion questions over time for turtle nest habitat, for instance. Known sea turtles for this region are predominately Olive`s Ridley turtle (Lepidochelys olivacea, TSN 17384), other species could potentially occur too. On the beach, we also detected Black-throated Magpie-Jay Calocitta colliei 558992, Balck Vulture Coragyps atratus 175272, Groove-billed Ani Crotophaga sulcirostris 177839, Great Kiskadee Pitangus sulphuratus 178301, Magnificent Frigate Bird Fregata magnificens 174763, Black Oystercatcher Haematopus bachman 176475, Sooty Tern Onychoprion fuscatus 824105, Brown Pelican Pelecanus occidentalis 174685, Neotropical Cormorant Phalacrocorax brasilianus 554375 and Banded Wren Thryothorus pleurostictus 563460). This dataset is an MS Excel format and less than 1MB in size.
    • GRID-based habitat plot data for the public nesting sea turtle beach of Pacuare, Caribean Sea, Costa Rica July of 2013

      Huettmann, Falk (Maderas Rainforest Conservancy, 2013-07-29)
      This GRID habitat survey was done at a globally relevant public sea turtle nesting beach: Pacuare (Playa Vigilada). It is situated at the Caribean Sea in Costa Rica ((latitude10.20123 longitude 83.25925; geographic datum WGS84). We did our grid-based habitat survey on 18th of July in 2013. The individual GRID points are geo-referenced by latitude and longitude (decimal degrees, +- 10 meters acuracy) and were visited only once (no 3 repeats because it consists of sand and private property) and no species information was taken (sand beach habitat). From 25 regular GRID points 15 were inaccessable because the nearby jungle and reserve. We took photos for every point (horizontally, ground and sky), more details can be seen there. This grid can for instance be used for change detection, shoreline location, develeopment, and beach erosion questions over time for turtle nest habitat. Known and observed sea turtles to occur for this region are Leatherback sea turtle (Dermochelys coriacea TSN 173843), and presumably Hawksbill sea turtle (Eretmochelys imbricata TSN 208666) and the Green sea turtle (Chelonia mydas TSN 173833). This dataset is in an MS Excel format and is less than 1MB in size.
    • Growth and nutritional development of reindeer (Rangifer tarandus) and muskoxen (Ovibos moschatus)

      Knott, Katrina K. (2004-08)
      Young ruminants must grow and develop digestive function during brief summers in the Arctic. I examined growth and development of nutritional organs in reindeer and muskoxen as neonates (1 d), during transition from milk to forage (30-60 d) and at maturity. Reindeer and muskoxen gave birth to relatively smaller offspring than ruminants from more temperate regions. Costs of small birth mass are likely offset in neonates by an increase of thyroid hormones to enhance thermogenesis and hepatic reserves that provide additional nutrients during early development. Body mass gains during the neonatal period (1-30 d) were associated with well-developed abomasa that allow young to utilize milk immediately after birth. Transition to forage coincided with mass gains of the rumen, small intestine and colon. Digestive morphology also was modified to facilitate fermentation of plants and enhance digestion and absorption of nutrients by 60 days of age. Digestive anatomy of young reindeer and muskoxen also indicated that feeding strategies of adults may be determined from birth. Growth of reindeer and muskoxen, therefore, is dependent upon an endogenous sequence of nutritional development that allow young to take advantage of concentrated milk after birth and time fermentative function to plant emergence at high latitudes. These advances permit young to meet requirements of growth and establish reserves before winter.
    • Growth of juvenile chinook salmon (Oncorhynchus tshawytscha) as an indicator of density-dependence in the Chena River

      Perry, Megan T. (2012-08)
      In management of Pacific salmon, it is often assumed that density-dependent factors, mediated by the physical environment during freshwater residency, regulate population size prior to smolting and outmigration. However, in years following low escapement, temperature may be setting the upper limit on growth of juvenile chinook salmon Oncorhynchus tshawytscha during the summer rearing period. Given the importance of juvenile salmon survival for the eventual adult population size, we require a greater understanding of how density-dependent and independent factors affect juvenile demography through time. In this study we tested the hypotheses that (1) juvenile chinook salmon in the Chena River are food limited, and (2) that freshwater growth of juvenile chinook salmon is positively related with marine survival. We tested the first hypotheses using an in-situ supplemental feeding experiment, and the second hypothesis by conducting a retrospective analysis on juvenile growth estimated using a bioenergetics model related to return per spawner estimates from a stock-recruit analysis. We did not find evidence of food limitation, nor evidence that marine survival is correlated with freshwater growth. However, we did find some evidence suggesting that growth during the freshwater rearing period may be limited by food availability following years when adult escapement is high.
    • Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus)

      George, John Craighead (2009)
      This thesis describes investigations on bowhead whales (Balaena mysticetus) conducted over the past three decades, specifically on age, growth, morphology and energetics. The examined whales were harvested by Inupiat Eskimo whale hunters primarily in Barrow, Alaska. Bowheads are robust cetaceans reaching 19 m in length and inhabit the ice-covered waters of the circumpolar Arctic. They have the thickest blubber (? 35 cm) of any cetacean and the longest (>4 m) and most extensive baleen apparatus. Bowheads are ~4 m at birth and grow rapidly to ~8 m in their first year; they then experience a 2-3 year growth pause in both body length and mass. However the baleen continues to grow during this period. Sex differences are minimal but adult females tend to grow longer than males and males have larger pectoral limbs. Based on several lines of evidence, bowheads may routinely live to 150 years and thereby the longest-lived mammal. The recovery of 19 th century stone weapons from recently harvested whales confirms these age estimates. Age was estimated for 48 whales using the aspartic acid racemization technique, based on intrinsic changes of aspartic acid within the eye lens. The age at sexual maturity for bowheads occurs in the mid-20s. All harvested whales examined showed strong thermal gradients through their blubber (dermis and epidermis). A similar thermal gradient was evident through the muscle which is atypical of most terrestrial mammals. The deep body temperature averaged 33.8�C (SD=0.83, N = 28) which is lower than in other non-hibernating eutherian mammals. I did not see elevation of body temperatures in chased whales -- in fact these whales had slightly lower core temperatures. Resting metabolic rates for whales were estimated using a heat-loss technique. The thermal conductivity of the blubber for 5 whales averaged about 0.23 Wm-1K-1; similar to that of other whales and marine mammals. Heat flux rates varied highest to lowest as follows: palatal rete, flukes, tongue and lowest for the thorax and flippers. The resulting metabolic rates were much lower (~ 1/3) than predicted by the Kleiber regression. These investigations suggest that bowhead whales are unique among mammals in several respects such as: (a) following weaning they appear to lose weight over a period of 2-3 years and grow little in body length, (b) resting metabolic rates and body temperatures are lower than in other cetaceans. Their extensive blubber likely buffers bowheads against high variability in primary and secondary productivity in arctic seas.
    • Gyrfalcon Breeding Biology In Alaska

      Booms, Travis L.; Huettmann, Falk; McCracken, Kevin (2010)
      This dissertation addresses specific research needs identified by a panel of experts on Gyrfalcon biology and conservation convened on 3 September, 2003 at the Raptor Research Foundation Scientific Conference in Anchorage, Alaska. The first chapter is a significant update and revision of the 1994 Gyrfalcon Birds of North America (BNA) species account, using all published papers and available grey literature from 1994--2007 and personal expertise from over 3,000 hours of coordinated observations. The second chapter reports results from a spatially explicit model, based on the best available compiled data from Alaska, that predicted Gyrfalcon breeding distribution and population size across Alaska. The model predicted that 75% and 7% of the state had a relative index of nest occurrence of <20% and >60%, respectively. Areas of high predicted occurrence primarily occurred in northern and western Alaska. Using environmental variables, the model estimated the size of the breeding Gyrfalcon population in Alaska is 546 +/- 180 pairs. In Chapter 3, I used repeated aerial surveys to estimate detection probabilities of cliff-nesting raptors from fixed-wing aircrafts and helicopters. Detection probabilities ranged from 0.79--0.10 and varied by species, observer experience, and study area/aircraft type. Generally, Gyrfalcons had the highest detection probability, followed by Golden Eagles, Common Ravens, and Rough-legged Hawks, though the exact pattern varied by study area and survey platform. In the final chapter, I described for the first time in North America Gyrfalcon nest site fidelity, breeding dispersal, and natal dispersal using molted feathers as non-invasive genetic tags. Gyrfalcons were highly faithful to study areas (100% fidelity) and breeding territories (98% fidelity), but not to specific nest sites (22% fidelity). Breeding dispersal distance averaged 750 +/- 870 m, and was similar between sexes. Natal dispersal of three nestlings representing 2.5% recruitment varied from 0--254 km. Mean territory tenure was 2.8 +/- 1.4 yrs and displayed a bimodal distribution with peaks at 1 and 4 years. Mean annual turnover at one study site was 20%. Gyrfalcons in one study area exhibited low, but significant population differentiation from the other two study areas.
    • Habitat associations, distribution, and abundance of Smith's longspur (Calcarius pictus), an uncommon species of concern in the Brooks Range, Alaska

      Wild, Teri Corvus; Powell, Abby; Verbyla, Dave; Kendall, Steve (2013-12)
      Smith's Longspur (Calcarius pictus) is a species of conservation concern in the U.S. and Canada, yet few studies have been conducted on their breeding grounds in the Arctic, which are expected to undergo dramatic changes due to climate change. For effective conservation, we need information on breeding distribution and abundance; thus I conducted surveys for Smith's Longspur and habitat characteristics across a broad geographic range that included twelve sites within Alaska's Brooks Range, June 2003-2009. My main objectives were to (1) locate breeding populations (2) describe habitats at local and broader geographic scales, (3) develop a predictive distribution map based on habitat characteristics, and (4) estimate densities and abundance of Smith's Longspurs. Smith's Longspurs were detected at seven of twelve sites and were associated with mixed sedge and shrub habitats with high cover of moss and sedges. Across the Brooks Range, I predicted patchy occurrence in valleys and foothills in the north- and south-eastern mountains and in upland plateaus in the western mountains. Density estimates varied, ranging from 0 - 0.39 males/ha due to their patchy distribution within and among sites. I estimated abundance as ~30,000 males in the Brooks Range. My data provides a baseline for future monitoring of this little-known species.
    • Habitat selection and sightability of moose in Southeast Alaska

      Oehlers, Susan A. (2007-08)
      We examined the role of scale and sex in habitat selection by radiocollared Alaskan moose (Alces alces gigas) on the Yakutat forelands, Alaska, USA. We used conditional logistic regression to quantify differences in habitats selected between sexes and seasons at 3 different spatial scales (250, 500, and 1000 m), and multi-response permutation procedure (MRPP) to test for differences in spatial distribution between the sexes. Sexes selected for habitats similarly during the mating season, when sexes generally were aggregated, whereas sexes exhibited differential habitat selection during the non-mating season when sexes were segregated. Both sexes selected habitats at the 1000 m scale; models limited to 2 variables, however, demonstrated differences in scales selected by the sexes. There was a significant difference between male and female spatial distribution during all months (MRPP; P <0.0001), and distances between individuals were higher in females than in males, particularly during spring. We also developed a sightability model for moose with logistic regression, and used Distance Sampling to develop sightability correction factors (SCFs). Application of the sightability model and Distance Sampling to a sample data set of 600 moose yielded population estimates of 652-1124 (x̄= 755) and 858-1062 (x̄ = 954) moose, respectively.