• Decomposition and adsorption of peptides in Alaskan coastal marine sediments

      Luo, Honghong (1994)
      In organic-rich coastal sediments, hydrolyzable amino acids make up a substantial fraction of the sedimentary content of organic nitrogen. How this organic nitrogen resists decomposition and is preserved in sediments is poorly understood. In order to investigate the factors controlling mineralization and preservation of hydrolyzable amino acids, decomposition and adsorption of peptides were studied in suboxic and anoxic pore water and sediments from Resurrection Bay (RB) and Skan Bay (SB), Alaska. Five tritium-labeled peptides, basic di-lysine, acidic di-glutamic acid, and neutral di-alanine, tri-alanine and hexa-alanine, were used as tracers. In filtered pore water, the hydrolysis rates were usually low. The exception was that the initial enzymatic hydrolysis of di-alanine and di-glutamic acid was rapid in SB pore water. The hydrolysis rates of both peptides increased with concentration. In sediments, hydrolysis was found to be the rate-limiting step of peptide decomposition. Alanyl and glutamyl peptides were hydrolyzed faster than lysyl peptide, and the hydrolysis rates among alanyl peptides decreased with increasing molecular weight. Peptide hydrolysis was affected more by molecular structure than by oxic or anoxic conditions. Adsorption of lysyl peptide to sediments was greater than that of other peptides. Basicity enhanced peptide adsorption more than increased molecular weight. Sedimentary organic matter was mainly responsible for peptide adsorption. The different patterns of peptide adsorption in RB and SB sediments were related to the greater total organic carbon concentration in SB sediment. Some of the peptide adsorption was irreversible. Adsorbed peptides were more resistant to biological decomposition than dissolved peptides. Adsorption may be an important step in the process of peptide preservation in sediments, and thus the preservation of sediment organic matter during early diagenesis.
    • Decomposition of dissolved organic matter in Arctic and boreal streams

      Mutschlecner, Audrey; Harms, Tamara; Jones, Jeremy; Guerard, Jennifer (2017-05)
      Arctic and boreal rivers connect terrestrial, oceanic, and atmospheric carbon (C) pools by transporting and processing dissolved organic matter (DOM). DOM composition influences its susceptibility to decomposition (biolability), which in turn determines whether the associated C is respired, stored, or exported. High-latitude ecosystems are changing rapidly due to processes such as permafrost thaw, shifts in vegetative communities, and increasing discharge, and each of these processes can influence the composition of DOM reaching rivers. The eventual fate of riverine DOM, whether it is mineralized or exported, shifts the balance of global C pools. Therefore, to understand how changes to high-latitude ecosystems influence the global C cycle, we must be able to connect patterns in DOM composition to its biolability and subsequent fate within the C cycle. The objectives of this study were to describe spatial and temporal patterns in DOM composition and biolability, and to determine links between the composition and biolability of DOM. I sampled DOM from streams along an Arctic-boreal gradient in interior Alaska throughout the year. I measured DOM biolability and nutrient limitation of decomposition in laboratory incubations and characterized DOM composition using optical properties and chemical analysis. I found that temporal patterns in DOM composition corresponded to seasonal trends in the hydrology of high-latitude catchments, linking DOM source to shallow, organic-rich flowpaths in spring and deeper groundwater flows in winter. Biolability was low, indicating that the majority of riverine DOM is recalcitrant to biological decomposition. I observed increased biolability in response to phosphorus (P) addition, particularly during spring, indicating that phosphorus limits DOM decomposition. To further examine the mechanisms driving C processing in streams, I also conducted a series of whole-stream experiments to compare the relative influence of molecular composition and nutrient content of DOM. I added leaf leachate to boreal streams and measured C retention, which represents both biological uptake and sorption. The leachates varied by molecular composition, due to differences in tissue chemistry of plant species, and in nutrient content, because the leaves were collected from plots with different fertilization regimes. Retention was greatest for leachates derived from trees that had been fertilized with P, indicating P-limitation of biological uptake of C or preferential sorption of P-containing organic molecules. Although leachates varied in molecular composition as determined by optical properties, these differences did not correspond to a difference in uptake rates by species. These patterns in DOM retention indicate that nutrient content is a greater constraint on C uptake than molecular composition. Together, the two studies suggest that export is the primary fate of ambient DOM in high-latitude streams, but that C processing is highly sensitive to inputs of bioavailable DOM. The coupling between the P and C cycles observed in both studies highlights the potential for nutrient availability to constrain or promote CO₂ emissions from C-rich, high-latitude catchments.
    • Decompression induced crystallization of basaltic andesite magma: constraints on the eruption of Arenal volcano, Costa Rica

      Szramek, Lindsay Ann (2004-08)
      Continuously active since 1968, Arenal Volcano in Costa Rica has undergone various eruption styles. The deposited magmas, whereas geochemically similar, show a complex history of magma chamber processes, which are not fully understood. The intricate mixing histories of the phenocrysts and lack of oxide pairs have made determination of the volatile content and oxygen fugacity difficult by conventional methods. Phase equilibria experiments were carried out between 200-50 MPa and 940-1075°C in a TZM furnace at fO₂ of NNO and water saturation. Time in the furnace varied from 7 to 30 hours at constant pressure and temperature. Examination of the natural and experimental phase assemblages constrained the probable pre-eruptive conditions for Arenal magmas to be 50-80 MPa and 950-1040°C. For decompression experiments, the sample was initially held at two conditions 200MPa and 950°C and 60MPa and 1050°C. The samples were then decompressed by 5-30 MPa pressure steps held for 20 seconds to 8 hours until 20 MPa was reached, approximating average decompression rates of 0.25, 0.025, and 0.0013 MPa/s. Textures formed in the experiments and seen in the natural samples constrain the probable ascent rate of the Arenal magma to 0.05 mls. The ascent rate increases as explosivity increases.
    • Deconstructing the western worldview: toward the repatriation and indigenization of wellness

      Rahm, Jacqueline Marie; Koskey, Michael; Lewis, Jordan; John, Theresa; Leonard, Beth (2014-12)
      As Indigenous peoples and scholars advance Native histories, cultures, and languages, there is a critical need to support these efforts by deconstructing the western worldview in a concerted effort to learn from indigenous knowledge and ways of knowing for humanity's future wellbeing. Toward that imperative, this research brings together and examines pieces of the western story as they intersect with Indigenous peoples of the lands that now comprise the United States of America. Through indigenous frameworks and methodologies, it explores a forgotten epistemology of the pre-Socratic and Pythagorean Archaic and Classical Greek eras that is far more similar to indigenous worldviews than it is to the western paradigm today. It traces how the West left behind this timeless wisdom for the "new learning" and the European colonial settlers arrived in the old "New World" with a fragmented, materialistic, and dualistic worldview that was the antithesis to those of Indigenous peoples. An imbalanced and privileged worldview not only justified an unacknowledged genocide in world history, it is characteristic of a psycho-spiritual disease that plays out across our global society. This dissertation suggests that the healing of the western mind rests with shifting the dominant paradigm toward a fundamental axiom of holism found within the life-ways of American Indigenous peoples and also buried within the West's own ancestry, particularly within a misunderstood ancient Greek tradition at the cornerstone of the western world.
    • Deeper than blood

      Brownlee, Yavanna M. (2006-05)
      The poems in 'Deeper than Blood' present a mosaic of geographic location, intensely personal events, friends, family, and observations tied together by a feminine persona who is not afraid to explore her life and the lives of those around her. Section I reaches into the depths of the persona's sexuality and fears of dying, revealing a shadowed and troubled side of the persona. Section II mixes views of the persona from an outside and an inside perspective, looking at how others view her as she stands naked before them and how she observes herself through her past and her memories of people and places. Section III searches through childhood memories, family, and friends for an answer to what comes next in life and after life is over. Throughout the intricate life story presented by these poems, a peaceful mood prevails. By setting the mood as one of calm, the speaker presents the rollercoaster ride of life. Instead of seeming like she is on a wild ride, the persona flows like a boat over the swells of an ocean on a calm day, allowing the reader to take in all the eccentricities of life with the calm that pervades the poetry.
    • Defining genetic population structure and historical connectivity of snow crab (Chionoecetes opilio)

      Albrecht, Gregory T.; Hardy, Sarah M.; Lopez, J. Andres; Hundertmark, Kris J. (2011-08)
      The snow crab (Chionoecetes opilio) is a valuable commercial resource within the Bering Sea, as well as other areas in the North Pacific and Atlantic Oceans. Large populations are known to exist within the Chukchi and Beaufort Seas, including recently discovered commercial sized individuals (Beaufort). However, genetic connectivity throughout these regions has not been examined until now. Based on seven polymorphic microsatellite loci, relatively low population genetic structuring occurs throughout the Alaskan region (Gst = 0.001). This homogeneity is likely due to long-distance larval dispersal, adult migrations, and a possible recent population expansion following the last glacial maximum. Furthermore, meta-population analysis was conducted for Alaskan and Northwest Atlantic stocks. Although significant genetic divergence characterizes the West Greenland stock in relation to all other populations, low divergence (Gst = 0.005) was found between Atlantic Canada crabs and those from the Alaska region. Larval dispersal between regions is highly unlikely due to the transit distance. Therefore, low divergence is likely the result of a recent population expansion into the Northwest Atlantic <5000 years ago.
    • Deformation microstructures, mechanisms, and history of a shear zone within the Chugach accretionary complex in the Nelchina area, South-Central Alaska

      Yakimova, Veselina T.; Nadin, Elisabeth; Mezger, Jochen; Regan, Sean (2020-05)
      Ductile-to-brittle fault zones reveal mineralogical processes that are thought to be responsible for the mechanical behavior of faults. I examined a pervasively deformed zone within the Jurassic to Cretaceous accretionary complex of southern Alaska that preserves hydrothermal alteration, dissolution precipitation, carbonaceous material (CM), clay minerals, and intracrystalline plasticity, all of which influence the strength of a fault. I characterized microstructures by SEM and EBSD, determined compositions by XRD, XRF, and Raman spectroscopy for one carbon-rich sample, and dated whole rock, rotated K-feldspar, and metamorphic muscovite by ⁴⁰Ar/³⁹Ar thermochronology to constrain the timing and conditions of accretion, uplift, and deformation recorded by this fault zone. I interpret the specific mineralogy and complex network of deformation microstructures as a result of multiple deformation events. Highest-temperature deformation recorded within the shear zone is lower greenschist facies (400-450°C). Quartz-rich clasts preserve deformation lamellae, grain bulges, sweeping undulose extinction, pressure solution, and brittle fractures characteristic of low grade (300-400°C) at the brittle-ductile transition. Brittle overprint is expressed by fractures cross-cutting the stretched quartz phacoids, and black fault rock that has entrained stretched quartz grains. Raman spectroscopy places precipitation of the CM at ~300˚C. I therefore associate the fault-rock fabrics with progressive down-temperature deformation as the fault was exhumed. I suggest that pressure solution and mineral alteration in all fault-zone samples, as well as quartz and phyllosilicate preferred orientation in a subset of the samples, indicate aseismic slip. Growth of clay and precipitation of CM reduced the friction coefficient, lowering the frictional strength and influencing the dynamic behavior of this fault zone. Constraining the relative timing of the different slip behaviors is hard to determine. It is possible they were active at the same time, especially with the increase of width and complexity at the deeper part of the fault. What is preferentially preserved in the rock record is the latest stage of slip. Pseudotachylite structures generated during earthquakes, however, are rarely preserved due to their susceptibility to alteration. In my field area, consequent exhumation and cooling lead to progressive down-temperature brittle deformation and strong hydrothermal alteration, which could have eradicated any evidence for frictional melting. Using ⁴⁰Ar/³⁹Ar thermochronometry alongside regional and local age constraints, I was able to provide some insight on timing of fault-zone and local tectonic activity. The fault lies between the McHugh Complex and Valdez Group, the two main components of the Jurassic to Cretaceous Chugach accretionary prism whose development and disruption is still debated. I interpret that fault activity lasted from ca. 120 Ma to ca. 60 Ma., and was followed by two stages of accelerated uplift and cooling during ca. 40 Ma and ca. 20 Ma. The cease of major fault activity after ca. 60 Ma, the lack of pervasive strike-slip motion indicators, and the presence of undeformed Eocene dikes as well as Eocene sediments deposited on top of both the McHugh Complex and Valdez Group, suggest they were deposited in proximity and were in place in Southern Alaska at the start of the Eocene epoch.
    • Deformation Of Alaskan Volcanoes Measured Using Sar Interferometry And Gps

      Mann, Doerte; Freymueller, Jeffrey (2002)
      Geodetic measurements using the Global Positioning System (GPS) and synthetic aperture radar interferometry (InSAR) show deformation of Okmok, Westdahl, and Fisher volcanoes in the Alaska-Aleutian arc. This thesis shows the variety of deformation signals observed, presents models for the observations, and interprets them in terms of underlying processes. InSAR data show deflation of Okmok caldera during its last eruption in 1997, preceded and followed by inflation of smaller magnitude. Modeling shows that the main deformation source, interpreted as a central magma reservoir, is located at 2.5 to 5.0 km depth beneath the approximate center of the caldera, and 5 km away from the active vent. Mass balance calculations and comparison with the long-term eruptive frequency indicate that Okmok may be supplied with magma continuously from a deep source. GPS measurements between 1998 and 2001 show inflation of Westdahl volcano, with a source located about 7 km beneath the summit. The combined subsurface volume increase measured during the GPS and an earlier InSAR observation period [Lu et al., 2000a] accounts for at least 15% more than the volume erupted from Westdahl in 1991--92, suggesting that an eruption of that size could occur at any time. Neighboring Fisher caldera shows subsidence and contraction across the caldera center that is not related to any eruptive activity. The main mechanisms to explain this deformation are degassing and contractional cooling of a shallow magma body, or depressurization of Fisher's hydrothermal system, possibly triggered by an earthquake in the vicinity of the caldera in 1999. A systematic coherence analysis of SAR interferograms documents the cooling history of the 1997 Okmok lava flow. The flow is incoherent directly after emplacement, but coherence increases as more time has passed since the eruption, and also the shorter the period spanned by the interferogram. Coherence is regained three years after the eruption. This corresponds to the time when the 20 m thick flow has solidified, indicating that flow mobility is the dominant factor degrading coherence on young lava flows. Based on these results, InSAR coherence analysis can be used to derive the minimum thickness of a lava flow.
    • Deg Xinag Oral Traditions: Reconnecting Indigenous Language And Education Through Traditional Narratives

      Leonard, Beth R.; Barnhardt, Raymond J. (2007)
      "Deg Xinag," literally 'local language' is the westernmost of the Athabascan 1 languages. The language area is also referred to as "Deg Hit'an," literally, 'local people'. The Deg Hit'an are often referred to inappropriately in anthropological and linguistic literature as "Ingalik," a Yup'ik word meaning 'lice-infested'. There are currently three villages in western, interior Alaska where this language is spoken and about 20 fluent speakers of this language remaining. As I proceeded through my graduate research I came to understand the significance of indigenous language revitalization in relation to its potential contributions to indigenous and cross-cultural education. These contributions include establishing and enhancing self-identity and self-esteem for indigenous students, as well as contributing in-depth knowledge about local environments thereby enhancing place-based and funds of knowledge educational models (Bamhardt and Kawagley 2005: 15; Moll 1990). This dissertation presents an interdisciplinary analysis of a complex, cosmological Deg Hit'an narrative entitled "Nil oqay Ni'idaxin" or "The Man and Wife" told in the Deg Xinag language by the late Belle Deacon of Grayling Alaska (1987b). Deacon also told her own English version and titled this "The Old Man Who Came Down From Above the Second Layer of the World" (1987c). Underlying structures and meanings used in the contexts of Deg Xinag oral traditions are currently lacking in most published materials for this language, making it difficult to learn and consequently, develop culturally-appropriate language learning programs and curriculum. This analysis encompasses the fields of Alaska Native/indigenous studies, anthropology, and folklore/oral traditions using philosophical and pedagogical frameworks established by indigenous scholars including Gregory Cajete, Oscar Kawagley, and Greg Sarris. 1The term "Athabascan" has varied spellings within the literature, including "Athapaskan" and "Athabaskan." In 1997, Tanana Chiefs Conference (TCC), the interior Alaska tribal consortium adopted a resolution stating their tribes' preference of the spelling using "b" and "c."
    • Delayed effects of oil exposure on fish

      Hicken, Corinne E.; Stekoll, Michael S.; Incardona, John P.; Smoker, William W.; Rice, Stanley D. (2012-05)
      Polycyclic aromatic hydrocarbons (PAHs) are continuously added to aqueous environments through point source and non-point source pollution and can cause deleterious effects on exposed fish populations. Historically, studies have shown that acute PAH exposure causes only short-term effects in adult fish which were resolved when the exposure ended. Chronic exposure to PAHs, however -- even at the less susceptible juvenile and adult stages -- can cause a host of effects including lesions, lower body length and weight, and reduced swimming ability. More recently studies of embryonic fish have demonstrated that much lower PAH concentrations can cause lethal and sub-lethal effects on those embryos and can cause delayed effects on the fish that are not seen until adulthood. This study used zebrafish (Danio rerio) to examine the effects of 48-hour weathered crude oil exposure on both the embryonic fish exposed and the adult fish exposed as embryos but raised in clean water. Oil exposed embryos had increased mortality, pericardial edema, intracranial hemorrhage, and higher cytochrome P4501A (CYP1A) activity. Adult fish exposed as embryos had decreased critical swim speed and rounder hearts than the control fish. These effects may culminate in decreased fitness of the exposed fish population.
    • Delineating drawdown lakes and Salix alaxensis in interior Alaska using Landsat TM and multitemporal SAR imagery

      Fogde, Julieanne L. (2001-08)
      This study evaluates the effectiveness of multitemporal Synthetic Aperture Radar (SAR) data and Landsat ETM+ imagery to delineate: 1) The locations of drawdown lakes within the Iditarod River drainage. 2) The locations of Salix alaxensis along the Innoko River. Both elements are related in that they constitute critical wildlife habitat, and their occurrence is largely due to seasonal flooding. Multitemporal, georeferenced Radarsat SAR imagery was used to classify lakes as either drawdown or non-drawdown. This technique yielded an overall classification accuracy of 78%, proving that multitemporal, georeferenced SAR is a good tool for delineating drawdown lakes. Landsat ETM+ imagery was used to develop three criteria (proximity to turbid water, broadleaf vegetation, and sandbars) to delineate S. alaxensis. Areas that met all three of the criteria had an estimated producer's accuracy of 4% for S. alaxensis, indicating that this technique is ineffective at delineating S. alaxensis.
    • Delineation of Yakutat foreland coho salmon (Oncorhynchus kisutch) stocks using otolith chemistry

      Jones, Matthew A. (2007-08)
      Otolith chemistry was utilized to identify suspected coho salmon sub-stock populations on the Yakutat Foreland of southeast Alaska. In order to demonstrate that otolith chemistry might be successful in sub-stock differentiation, water samples were collected from four adjacent river systems and chemically segregated by collection site. Juvenile coho salmon and adult coho salmon were collected from the same four river systems and were subsequently analyzed for levels of select Ba, Ca, Mg, and Sr isotopes in all otolith edge and core regions using laser ablation-inductively coupled plasma-mass spectrometry. Otolith Sr⁸⁷/Ca⁴⁸ and Mg²⁴/Ca⁴⁸ were used to segregate collection sites, identify sub-stock populations, and infer straying rates for coho salmon on the Yakutat Foreland. Juvenile core and edge otolith chemistry returned moderate to high classification accuracy for three out of four collection' sites (60%-92%) in statistical discriminant analyses. Adult core otolith chemistry could not segregate samples according to collection site in three out of four sites (7%-50%). Yakutat Foreland otolith chemistry analysis results allowed for (1) differentiation of adjacent freshwater systems, (2) a significant amount of coho salmon stock delineation, and (3) a higher suggested rate of straying from natal sites than coho salmon in other locations.
    • Demographic and social consequences of oil and gas development in Siberia, 1960s-early 1990s

      Logunov, Eugene V.; Black, Lydia (1999)
      The main goal of this thesis is to study the demographic and social consequences of rapid oil and gas development in Siberia, to show the experience of solving or failing to solve of wide range of social and cultural issues, and to sum up the results of both the economic impact on the social-cultural processes and the social impact on industrial production. In three decades, the number of new settlers in the Tyumen province was no less than 2,000,000 people. Such a pace of settling previously uninhabited territories with extreme environmental conditions had never occurred before in world practice. This explosive growth of population, dominated by young single males, has resulted in a distorted demographic structure which is hardly capable of reproduction. The birth rate declined sharply, whereas the death rate grew because of accidents, diseases, alcoholism, narcotics addiction, etc. The situation has been aggravated by complete neglect of the development of a social infrastructure. Nearly half of population live in conditions conducive to the degradation of family, morals, health and cultural values. Oil and gas development had numerous negative effects on indigenous peoples of the North. Destruction of the environment has undermined the natural base and functioning of their traditional occupations. They were unable to adapt to the new kinds of economic activity, and social and physical problems have become aggravated. There has been growth of the disease rate and of alcoholism. The descent into poverty has been rapid, and they find themselves under threat of ethnic degeneration and extinction. It was the initial orientation toward creation of a new but permanent population, the politics of "development through settlement," that proved to be one of the main causes of the deep crisis which has affected the region. The formation of a large, heterogeneous, unstable population, taken together with all its problems, accompanied by the inability to create a favorable social environment, mismanagement of manpower resources and an inadequate social infrastructure, have become the leading causes of production failures in the oil and gas industry.
    • Demographic components of philopatry and nest-site fidelity of Pacific black brant

      Lindberg, Mark Steven; Sedinger, James S. (1996)
      I investigated demographic components of nest-site fidelity and philopatry of Pacific black brant (Branta bernicla nigricans). My analyses included data I collected during summer 1990-1993, and also incorporated data obtained between 1986-1989. My studies of nest-site fidelity were limited to the Tutakoke River colony, Yukon-Kuskokwim River Delta, Alaska. Studies of philopatry and dispersal among colonies included observations at 7 breeding colonies of brant marked with tarsal tags (n = 20,147). I observed strong evidence that philopatry of brant was female biased. Probability of breeding philopatry, which was estimated with multi-state modeling techniques, was high (>0.9) and dispersal of adults among breeding colonies was rare. I developed an ad hoc estimator for natal philopatry that was unbiased by a confounding of homing, survival, and detection probabilities. Probability of natal philopatry for females was both age and density dependent. The density-dependent decline in natal philopatry may result from increased rate of permanent nonbreeding or increased probability of dispersal. Observed probability of natal philopatry for males was approximately equivalent to the relative size of their natal colony, suggesting that males pair at random with females from other colonies. Gene flow among populations of brant is largely male mediated, and I predict populations of brant will exhibit distinct mitochondrial DNAs if populations have been reproductively isolated for an adequate period of time. Probability of fidelity to previous nest sites for adults was high (>0.7). Probability of nest-site fidelity was affected by previous nesting success, age, and availability of nest sites. Phenology of nesting, nest-site selection, and clutch size of brant was affected by spring snowmelt. Dispersal of brant from traditional nest sites in years with late springs may represent a tradeoff between site fidelity and timing of nest initiation. Movement of young females from natal nest sites was a mechanism for colony expansion. I observed little evidence that site fidelity was advantageous, and concluded that quality of individual bird, environmental conditions, and demographic status may be more important determinants of breeding performance.
    • Demographics and telomere dynamics of hibernating Arctic ground squirrels (Urocitellus parryii)

      Wilbur, Sara M.; Williams, Cory; Barnes, Brian; Kitaysky, Alexander; Podlutsky, Andrej (2019-08)
      Aging is the complex process by which an organism loses functional integrity over time. Several measurable contributors to or components of the aging process have been identified, one of which is telomere length. Telomeres are the repetitive, nucleoprotein structures located at the ends of linear chromosomes. In general, telomeres shorten over time and when exposed to damaging reactive oxygen species (highly unstable molecules released as a byproduct of cellular respiration). Organisms that have unique physiologies, in addition to those that live longer than otherwise predicted, have recently inspired comparative telomere dynamics studies. Hibernating mammals, which exhibit both heterothermy and long lifespan, have served as models for these new investigations into telomere length dynamics. Several studies over the past decade have measured the effects of torpor (the period of hibernation characterized by extremely low metabolic rates and body temperature) and arousal (from torpor; a brief return to euthermic or high levels of body temperature) on telomere length change in hibernators. This body of work demonstrated that telomere length is preserved across hibernation seasons (likely due to the majority of hibernation spent in torpor), and any telomere shortening that does occur is correlated with arousal frequency. However, all telomere-hibernator studies to date have focused on hibernators from temperate regions and on DNA from a peripheral tissue (either buccal cells or skin tissue). Arctic ground squirrels, the northernmost hibernator and ground squirrel species, are appropriate model candidates to expand the diversity of research in hibernator telomere dynamics, as they remain thermogenic during torpor to defend a viable body temperature against subfreezing ambient temperatures. Maintaining high metabolic rates to support thermogenesis throughout torpor--and over arousals--may lead to increased telomere attrition in this species compared to other hibernators adapted to milder climates. This thesis begins with basic arctic ground squirrel demographics from two well-studied populations in Arctic Alaska. I report that (female) arctic ground squirrels appear to be similarly long-lived as other hibernating species, and that sex-specific differences in lifespan may be driven by behavioral differences between males and females. I also present results from a study comparable to those performed in temperate hibernators: I measured telomere length in freeliving arctic ground squirrels across hibernation and age groups and found that, as in temperate hibernators, telomere length (in ear tissue) is maintained across hibernation. Expanding upon single-tissue telomere studies, I also measured telomere length in brown adipose tissue (the tissue responsible for non-shivering thermogenesis for heat generation during torpor and at arousal initiation), liver, and heart in captive arctic ground squirrels and found that telomeres shortened dramatically in brown adipose tissue only. Overall, this work identifies arctic ground squirrels as capable of maintaining cellular integrity (as measured via telomere length) and of reaching surprising longevity in the face of extreme environmental conditions.
    • Dena'ina duch'deldih: "we are learning Dena'ina," language goals and ideologies among adult learners of Dena'ina Athabascan

      Bell, Lindsay A. (2006-05)
      The work contained herein consists of two research papers that emerged from a single qualitative study of goals and ideologies of adult learners of Dena'ina Athabascan in attendance at the 2005 Dena'ina Language Institute. The study draws upon 19 semi-structured, in-depth interviews that were collected and analyzed in order to increase community control over the program and to assist in the development of future programming offered by the University of Alaska Fairbanks. The first research paper suggests that goals of attendees clustered into four categories: fluency, literacy, cultural knowledge, and community building. More important than these four stated goals were the ways in which these goals connected to overarching themes of visibility, healing and resistance. It is argued that these themes are interconnected forms of, and tools for, empowerment. The second research paper suggests that the presence and work of university representatives is always ideological and always educational. It outlines the importance of ideological critique on the part of both community and institution when goals of empowerment are being sought after. The work contains both-site specific recommendations and broader implications for educational institutions involved in Native language programming.
    • A dendroclimatological study of long-term growth patterns of yellow-cedar trees in Southeast Alaska

      Sink, Scott E. (2006-08)
      Yellow-cedar is a very long-lived, commercially important tree species found along the coasts of Southeast Alaska and also in small populations in Prince William Sound. However, this is the first study of the tree's annual ring growth patterns in the region. Tree cores were collected from over 400 trees across a large latitudinal gradient and cross-dated using standard dendrochronological techniques. Radial tree-ring growth was measured and compared to reconstructed weather station data to gain a better understanding of the climatic conditions favoring yellow-cedar growth. We found consistent, significant positive correlations between ring widths and mean monthly temperatures in August, previous January, and previous December, and negative relationships with May and December precipitation. Climate indices we created using these variables explain approximately 25% of growth variability in five distinct yellow-cedar populations. Long-term growth patterns in tree populations going back three centuries were similar across all sites, specifically the sustained below mean growth during the 1800s. Yellow-cedar at the northern limits of its distribution shows a common growth signal which may indicate the influence of larger pressure anomalies, such as EI Nino-Southern Oscillation (ENSO), on the climate factors affecting the trees.
    • Denitrification in a subarctic lake

      Clasby, Robert Charles (1972-05)
      The rates of denitrification for an ice covered subarctic lake were measured by nitrogen-15 tracer techniques and the results compared to the measured decrease of nitrate in the lake during the same period. The effects of nitrate, glucose, acetate and phosphate concentration on the rate of denitrification were also investigated. Good agreement was found between the rate of denitrification and the loss of nitrate. The average rate of denitrification for the period measured was 5 µg N/ℓ·day which is in good agreement with rates determined for other subarctic and temperate lakes and semi-tropical marine environments. Glucose, acetate and phosphate were found to enhance the rates of denitrification.