• Resource Partitioning Among Sympatric Stellar Sea Lions And Northern Fur Seals On Lovushki Island, Russia

      Waite, Jason N.; Andrews, Russel; Castellini, Michael; Atkinson, Shannon; Rea, Lorrie; Trumble, Stephen (2010)
      The competitive exclusion principle maintains that one of two non-interbreeding species occupying the same ecological niche and geographical territory will be displaced if population growth is not the same between species. Steller sea lions (Eumetopias jubatus; SSL) and northern fur seals (Callorhinus ursinus; NFS) breed sympatrically on four rookeries in the Russian Far East, creating the potential for inter-specific competition for limited prey resources. Approximately 1,000 SSL and 14,000 NFS breed on Lovushki Island in the Kuril Island chain. An additional 13,000--14,000 juvenile NFS are present during the breeding season. The partitioning of forage resources among breeding SSL and both breeding and non-breeding NFS from 2003--2008 was examined through analysis of prey remains recovered from scats and spews, stable isotope (SI) analysis of vibrissae, fatty acid (FA) analysis of blubber, and analysis of foraging behavior through satellite-linked telemetry. Analysis of prey remains indicated a biologically significant overlap in the prey species and size selection of SSL and juvenile NFS and significant differences between the diets of SSL and breeding NFS. SSL fed primarily on Atka mackerel, while breeding NFS fed primarily on cephalopods and northern smoothtongue. SI analysis indicated significant differences in the trophic level and relative foraging location. SSL foraged at a higher trophic level, nearshore, and benthically, while NFS foraged at a lower trophic level, offshore, and pelagically. Analysis of FA signatures also suggested significant differences in the relative diets of breeding NFS and SSL. Foraging behavior analysis also indicated that SSL foraged nearshore and benthically and breeding NFS foraged offshore and pelagically. The combination of these four methodologies suggests breeding NFS and SSL partition their forage resources by prey type and prey size, as well as spatially. This partitioning of resources between breeding animals currently allows both species to coexist within the same geographical region and likely reflected the differences in foraging abilities and provisioning strategies of the adults, as well as the fasting abilities of their pups. However, continued growth of the non-breeding NFS population on Lovushki Island may lead to the competitive exclusion of SSL due to inter-specific competition for food resources.
    • Resource partitioning between breeding common (Uria aalge) and thick-billed murres (Uria lomvia)

      Barger, Christopher Paul; Kitaysky, Alexander; O'Brien, Diane; Takebayashi, Naoki (2013-05)
      In seabirds, food availability is a driver of ecological and evolutionary processes. Here we examine how changes in food availability and energy demands affect both inter-specific resource partitioning and the genetic diversity within a species. We examined the effects of interannual fluctuations in food availability and predictable seasonal increases in energy demands on prey partitioning between breeding common (Uric aalge) and thick-billed (U. lomvia) murres. We observed strong spatial, temporal and dietary differences in the use of prey resources between the species. We found that partitioning increased as food availability declined and as energy demands increased during chick-rearing. We conclude that murres can buffer negative effects of warming and increased energy demands by reducing inter-specific competition for limited food resources. We also investigated the effects of contrasting foraging conditions and population trajectories on the genetic structure of common murres. We found that birds breeding on an increasing food-rich colony had higher genetic diversity than conspecifics breeding on a declining food-poor colony. This may be indicative of changes in a relative strength of purifying selection operating on increasing versus declining colonies. We conclude that foraging conditions might be driving the pattern of the genetic diversity in the Pacific common murre population.
    • Resource Partitioning By Sympatric Brown And American Black Bears

      Belant, Jerrold L.; Fullmann, Erich H. (2006)
      The fundamental niche of a species is rarely if ever realized because the presence of other species restricts it to a narrower range of ecological conditions. Additionally, distribution theory predicts that for two competing species living in sympatry, the subordinate species will be constrained from optimal resources. This constraint would result in use of lower quality resources by the subordinate species and possible spatial segregation from the dominant species. I evaluated diet in relation to body condition and reproduction for sympatric brown bears (Ursus arctos) and American black bears (U. americanus) in southcentral Alaska during 1998-2000, and assessed spatial segregation and habitat selection in 2000. Based on isotopic analysis, salmon (Onchorhynchus spp.) predominated in brown bear diets (>53% annually) whereas black bears assimilated 0-25% salmon annually. Black bears did not exploit salmon during 1998, a year with below average spawning numbers, probably because brown bears deterred black bear access to salmon. Enhanced body condition (as indexed by increased percent body fat) from salmon consumption resulted in better body condition the following spring. Further, black bear reproduction was directly related to body condition; reproductive rates were reduced when body condition was poorer. Analyses of radio location data confirmed that 24-hour monitoring of bears was necessary to determine habitat use and that habitat use varied seasonally. Black bears avoided areas occupied by brown bears during summer, supporting the ideal despotic distribution model. In contrast, black bears selected areas where brown bears were present during spring, presumably because of spatially-restricted (i.e., restricted to low elevations) but dispersed availability of food. Similarities in preferred and potentially limited resources resulted in co-occupancy of areas at intermediate to coarse spatial resolutions; however, spatial avoidance of brown bears and black bears influenced population-level use of resources. Further, the realized niche of black bears was constrained by brown bears through partitioning of food resources, which varied among years. Reduced access to salmon caused black bears to forage more extensively in areas containing less nutritious food, resulting in lowered body condition and subsequent lowered reproduction. Coexistence of these species in this study area appears dependent on the distribution, abundance, and availability of salmon and berries.
    • Resources, support, and advocacy for Alaskan secondary school students who identify as LGBTQIA+

      Nickell, Jasmine L.; Gifford, Valerie; Dahl, Heather; Wilson, Hilary (2017-05)
      This comprehensive literature review presents findings associated with the needs of students in grades 7-12 who identify as lesbian, gay, bisexual, transgender, questioning, intersex, and/or asexual (LGBTQIA+). In addition, the roles of school counselors, faculty, and staff in addressing these needs are discussed, and policy decisions and legislation supporting safe and inclusive environments are examined. A comprehensive guidebook is included which explains the legislative process that can be used to promote systems change in order to address these needs. The legislative proposal in this guidebook would mandate Alaskan school counselors receive proper training, resources, and guidance to appropriately support and advocate for students who identify as LGBTQIA+. Although there are legislative bills currently being introduced to the Alaska Legislature that support more inclusive anti-discrimination state-based laws, Alaska has yet to pass such a bill and its efforts remain inadequate concerning the institution of state law preventing bullying, discrimination, and violence in schools based on a student's gender identity, gender expression, and/or sexual.
    • Response of Alaskan wells to near and distant large earthquakes

      Sil, Samik (2006-08)
      We observed water level changes in groundwater wells in Alaska following the large 2002 Nenana Mountain and the Denali fault earthquakes. Multiple mechanisms must be responsible for the variable temporal pattern and the magnitude of the observed water level changes. For the wells in a consolidated confined aquifer system, poroelastic theory explains the water level changes. However for the wells in a partially confined unconsolidated aquifer, 1) fracture formation due to an earthquake which changes the permeability of the aquifer, or 2) consolidation of the unconfined aquifer in host rock by earthquake induced dynamic strain (liquefaction) are both important mechanisms. For each well the dominant mechanisms are the same for both earthquakes. For the group of wells where dynamic strain is the cause of water level changes, we also observed water level changes due to the 2004 great Sumatra-Andaman earthquakes. Though more than 10000 km away, the Sumatra earthquake induced water level changes that are very consistent with the changes due to the local large earthquakes. Along with the determination of the mechanics of the well water level changes in Alaska, we also determined general hydrological parameters of the wells which can be helpful for future studies.
    • The response of juvenile coho and chinook salmon stocks to salmon spawner abundance: marine nutrients as drivers of productivity

      Joy, Philip J.; Wipfli, Mark S.; Adkison, Milo D.; McPhee, Megan V.; Stricker, Craig A.; Rinella, Danial J. (2019-08)
      Resource subsidies from spawning Pacific salmon (Oncorhynchus spp.) in the form of marine-derived nutrients (MDN) benefit juvenile salmonids while they rear in fresh water, but it remains unclear if the abundance of spawners in a watershed affects the productivity of salmon stocks that rear in those riverine systems. This dissertation aimed to provide a better understanding of these dynamics by evaluating whether the response of juvenile salmon to MDN is sufficient to enhance overall stock productivity. In Chapter 1, I examined correlative relationships in the abundance of Pink (O. gorbuscha) and Coho (O. kisutch) salmon and simulated spawner-recruit dynamics to determine if those correlations were produced by a Coho Salmon response to marine subsidies from Pink Salmon, a shared response to marine conditions, and/or autocorrelations in the returns of both species. Results demonstrated that observed correlative patterns most closely resembled simulated freshwater effects, providing evidence that marine subsidies from Pink Salmon influence Coho Salmon productivity. In Chapter 2, I examined the relationship between spawner abundance and MDN assimilation by juvenile Coho and Chinook (O. tshawytscha) salmon in the Unalakleet River watershed. Stable isotope analysis demonstrated that after salmon spawned, MDN assimilation by juvenile salmon in the fall was a function of adult Pink and Chinook salmon spawner abundance, regardless of the habitat occupied by rearing juveniles. However, by the following summer, high retention of MDN in complex habitat masked seasonality of MDN assimilation in sloughs and river sections with abundant lentic-lotic exchanges. As such, MDN assimilation in the summer (prior to arrival of spawners) bore only a faint relationship to spawner abundance and distribution from the previous year. In chapter 3 I examined the relationship between MDN assimilation (Chapter 2) and juvenile salmon growth, size, body condition, and abundance. Prior to salmon spawning, residual MDN from past years offered little advantage to juvenile salmon. However, after the arrival of spawning salmon, MDN enhanced juvenile salmon size, growth, and condition in fall and winter. The collective results from this dissertation thus provides compelling evidence that MDN from spawning Pink Salmon may enhance the productivity of Coho and Chinook salmon. Management agencies should explore modified spawner-recruit models that incorporate MDN relationships to determine if they more accurately describe population dynamics. Where they do, such models may be used to forecast salmon returns and possibly adjust escapement goals (the number of spawners desired on the spawing grounds) to improve maximum-sustained yields (MSY).
    • Response of major modes of eastern Arctic Ocean variability to climate change

      Baumann, Till M.; Polyakov, Igor V.; Bhatt, Uma S.; Walsh, John E.; Weingartner, Thomas J. (2019-12)
      The Arctic Ocean plays a central role in ongoing climate change, with sea ice loss being the most prominent indicator. Recent observations showed that Atlantic inflows play an increasingly important role in the demise of sea ice. This encroaching atlantification of the eastern Arctic Ocean impacts the mean state and the variability of hydrography and current dynamics throughout the basin. Among the most energetic modes of variability are the seasonal cycle and high frequency semidiurnal (∼12-hourly) dynamics in the tidal and inertial frequency band. Limited observations indicated a substantial increase of both, hydrographic seasonal cycles as well as semidiurnal current dynamics in the eastern Arctic over the last decade. Using a uniquely comprehensive data set from an array of six moorings deployed across the eastern Eurasian Basin (EB) continental slope along the 125°E meridian between 2013 and 2015 within the NABOS project, we assess the state of hydrographic seasonal cycles in the eastern EB. Results show a complex pattern of seasonality with a remarkably strong (∆T=1.4°C), deep reaching (∼600 m) temperature signal over the continental slope and large-scale seasonal displacements of isopycnal interfaces. Seasonally changing background conditions are also the main source of variability of semidiurnal frequency band currents: During winter, vigorous baroclinic tidal currents whose amplitudes by far exceed predictions follow the vertical evolution of the pycnocline. During summer, extensive open-water periods additionally lead to strong wind-driven inertial currents in the upper ocean, routinely exceeding 30 cm/s far offshore in the deep basin. In order to obtain an Arctic-wide perspective on the impact of baroclinic tidal currents, a pan-Arctic tidal current atlas has been developed that synthesizes all available observations from the last 20 years. This atlas allows for in-depth studies of regional baroclinic tidal current variability as well as for validation of ocean and climate models, an essential step towards more accurate projections of the future Arctic Ocean state. Our findings from the eastern EB region already indicate a new, more dynamic state of the eastern Arctic Ocean with direct implications for the ecosystem and further sea-ice reduction.
    • Response of northern red-backed vole (Clethrionomys rutilus) populations to a major spruce beetle infestation in the Copper River Basin, Alaska

      McDonough, Thomas (2000-08)
      A spruce bark beetle (Dendroctonus rufipennis) epidemic in the Copper Basin of Alaska beginning in the late 1980's has infested over 200,000 ha of white spruce forests in the region. The impact of spruce beetle-induced habitat changes on the northern red-backed vole (Clethrionomys rutilus) was investigated using mark/recapture techniques for 2 field seasons. Vole abundance and recruitment was significantly greater on low versus heavily infested sites but a large vole survival response was lacking. Vole food resources and protective vegetative cover did not vary substantially in areas with different levels of spruce mortality. Male movement distances were influenced by sex ratio, and females appeared to respond to food resources (epigeous sporocarps). Beetle infestations alone did not influence vole movements, but female movement distances decreased when heavy infestation levels were coupled with female age and sporocarp availability. The impact of beetle infestations on red-backed vole populations in the Copper Basin appears to be relatively small.
    • Response of pile-guided floats subjected to dynamic loading

      Quan, Zhili; 权致力; Chen, Gang; Metzger, Andrew; Hulsey, Leroy (2013-12)
      Pile-guided floats can be a desirable alternative to stationary berthing structures. Both floats and guide piles are subjected to time varying (dynamic) forces such as wind-generated waves and impacts from vessels. There is little design information available concerning the dynamic load environment to which the floats will be subjected. So far, the most widely acceptable method used in offshore structure design is the Kinetic Energy Method (KEM). It is a simplified method that is based on the conservation of energy. This approach is straightforward and easy to implement. However, in spite of its simplicity and straightforwardness, the method lacks accuracy. The intent of this project is to develop a rational basis for estimating the dynamic response of floating pile-guided structures, providing necessary insight into design requirements of the guide-piles. In this study, the Dynamic Analysis Method (DAM) will be used to model the dynamic responses of the system. MATLAB codes are written to help calculate the analytic and numerical values obtained from the dynamic models. For the purpose of validation, results from the two systems should be compared to a comprehensive dynamic analysis model created with the ANSYS AQWA Software.
    • Responses of captive common eiders to implanted satellite transmitters with percutaneous antennas

      Latty, Christopher J. (2008-05)
      Implanted transmitters have been used for over a decade to track the migrations and habitat use of many sea duck species, but their effects remain largely unstudied. To address this, I assessed the physiological and behavioral responses and characterized the clinical responses of six Common Eiders implanted with a transmitter with a percutaneous antenna. To maintain a semi-natural feeding regime, I fed birds benthicly in a 4.9 m deep dive column. I collected blood, feces, mass, and video data prior to surgery to establish baselines and at staggered intervals for 3.5 months post surgery to determine responses. All birds had some clinical complications, but most abated within 2 weeks of surgery. Mass increased in the first two weeks, but no trend was evident thereafter. Most biomarkers and dive performance metrics were altered at some point after surgery. While most biochemical values returned to baseline within weeks of surgery, a few remained deviated for longer. Additionally, dive speeds were slower for up to 3.5 months after implantation. Although it is uncertain how these changes would ultimately affect birds in the wild, effects on physiological condition and behavior seem likely in the first few weeks after surgery with longer-term effects also possible. Scientists should consider these responses and possible effects on the validity of PIT data when designing studies and analyzing information from implanted transmitters in sea ducks.
    • Restorative practices as tools for reducing the outcome data gaps in the Fairbanks North Star Borough School District

      Kettle, Anne; Gifford, Valerie; McMorrow, Samantha; Repetto, Elizabeth (2018)
      Childhood adversity, toxic stress and trauma have physical and mental health impacts on individuals and affect academic and career success. The result of which may present as challenging or off-task behavior in the classroom. Trauma-informed techniques are being implemented to address these challenges in schools and classrooms across the United States. Restorative practices are proving to serve as successful tools for mitigating the impact of adversity on students and build a more cohesive and successful school atmosphere. There is potential for restorative practices to be used by school counselors as part of a comprehensive school counseling program to work to close gaps in the rates of graduation, suspension/expulsion and attendance between students from the majority population and those from traditionally marginalized populations. Based on a review of the literatures of trauma-informed schools, restorative practices and school counselor roles, a presentation and tool-kit has been developed for the Fairbanks North Star Borough school counselors. This tool-kit builds awareness around the impact of trauma, restorative practices and provides resources to support their implementation in this district via school counselors.
    • Rethinking the Redoubt: Kolmakovskiy Redoubt, a fur trading post on the middle Kuskokwim

      Hilsinger, Erik Deforest (2002-08)
      "Kolmakovskiy Redoubt is a multi-component site in the Middle Kuskokwim River region. It operated from 1840 to 1925 and includes evidence of Russian, Eskimo, Deg Hit'aan, and Euro-American occupations. Dissatisfaction with the report and the availability of the collection at the University of Alaska Museum led to reexamination of the site. The collection of artifacts was examined, identified and recorded. Information about the stratigraphy, details of construction, and function of excavated structures are presented in a clearer fashion. Historical information about the people who lived or traded there and historical information about the material culture left behind was synthesized. New conclusions were reached that differ significantly in some cases from Oswalt's original conclusions. Alaska Natives and Creoles operated the Redoubt, and little material culture evidence separates them. American period occupation results in the advent of vast amounts of manufactured imported goods, dubbed technofacts, which clearly distinguish this occupation"--Leaf iii.
    • Retrodirective phased array antenna for nanosatellites

      Long, Justin W.; Thorsen, Denise; Kegege, Obadiah; Hawkins, Joseph; Mayer, Charles (2019-12)
      This thesis presents a S-band phased array antenna for CubeSat applications. Existing state-of the-art high gain antenna systems are not well suited to the majority of CubeSats, those that fall within the 1U (10 cm x 10 cm x 10 cm) to 3U (10 cm x 10 cm x 30 cm) size ranges and in Low Earth Orbit (LEO). The system presented in this thesis is designed specifically to meet the needs of those satellites. This system is designed to fit on the 1U face (10 cm x 10 cm) of a CubeSat and requires no deployables. The use of beamforming and retrodirective algorithms reduces the pointing requirements of the antenna, easing the strict requirements that high gain antennas typically force on a CubeSat mission. Additionally, this design minimizes volume and uses low cost Commercial-off-the-Shelf (COTS) parts. This thesis discusses the theoretical background of phased array theory and retrodirective algorithms. Analysis are presented that show the characteristics and advantages of retrodirective phased antenna systems. Preliminary trade studies and design analyses show the feasibility and expected performance of a system utilizing existing COTS parts. The preliminary analysis shows that an antenna system can be achieved with ≥8.5 dBi of gain, 27dB of transmitted signal gain, 20% Power Added Efficiency (PAE) within a 1 W to 2 W power output, and an 80° effective beamwidth. Simulation results show an example antenna array that achieves 8.14 dBi of gain and an 82° effective beamwidth. Testing results on a prototype of the front-end electronics show that with minimal calibration, the beamforming and scanning error can be reduced to 5°. The power consumption and signal gain of the electronics is also verified through testing. The CubeSat Communications Platform, a CubeSat mission funded through the Air Force Research Laboratory is in Phase A design to demonstrate this antenna system, along with other experimental payloads. This thesis includes a discussion of interface control, mission requirements, operations, and a recommended experiment sequence to test and verify the antenna system on orbit.
    • Retrogressive thaw slumps and active layer detachment slides in the Brooks Range and foothills of northern Alaska: terrain and timing

      Balser, Andrew W.; Jones, Jeremy B. Jr; Walker, Donald A.; Mack, Michelle C.; Gens, Rudiger (2015-05)
      Permafrost degradation is widespread throughout the circumpolar north, occurring by multiple modes and mechanisms on many types of landscapes. The pan-Arctic rate of permafrost degradation is reportedly increasing, and permafrost carbon and nitrogen release are likely to be major contributors to global atmospheric greenhouse gas concentrations in coming decades. Locally, liberation of previously frozen substrates, organic materials, and nutrients alters the ecology of receiving streams, causes ecological and hydrobiogeochemical impacts in lake ecosystems, and impacts vegetation through disturbance, nutrient release, and succession on altered surfaces. Understanding the diverse modes of permafrost landscape response to climate, within time and space, is critical to questions of future impacts and feedbacks to climate change. Active layer detachment sliding and retrogressive thaw slumping are important modes of upland permafrost degradation and disturbance throughout the low arctic, and have been linked with climate warming trends, ecosystem impacts, and permafrost carbon release. In the Brooks Range and foothills study region of northwest Alaska, active layer detachment slides and retrogressive thaw slumps are widespread and prominant modes of permafrost degradation. Their distribution has been partially correlated with landscape properties, especially upper permafrost characteristics. However, drivers of active layer detachment slide and retrogressive thaw slump distribution and initiation triggering mechanisms, are poorly understood in this region, and detailed spatial distribution of permafrost characteristics is particularly lacking for the entire area. To better understand retrogressive thaw slump initiation triggers, this research used archived ERS-1 synthetic aperture RADAR data (1997-2010) to determine the year of first detection for 21 active retrogressive thaw slumps in the Noatak Basin, and examined weather records from remote and regional weather stations (1992-2011), along with satellite image-derived seasonal snowpack distribution (2000-2012) for correlations among weather, snowpack duration, and the timing of retrogressive thaw slump initiation. Most slumps first appeared within a 13 month span beginning June of 2004. Early summer 2004 was distinct in the weather records for anomalously warm early thaw-season temperatures, intense rainfall events in May, and unusually early dissipation of the annual snowpack. Results suggest that, regionally, retrogressive thaw slump initiation may be clustered in time, in response to seasonal shifts or anomalous weather events, and that future landscape response to climate change may depend on the nature and timing of climate change as much as overall magnitude. SS_para>The project examined inter-related and co-varying terrain properties at specific sites to identify relationships among terrain properties and permafrost characteristics. Consistent relationships among vegetation, surficial geology and permafrost characteristics were found using multiple factor analysis ordination of empirical data from diverse field sites throughout the region. Ordination results suggest relevant relationships among these factors to support regional-scale spatial analysis of terrain and permafrost properties. Field sites were also found to form consistent groupings from hierarchical clustering of ordination results, suggesting that relationships among these factors remain relevant across diverse gradients of landscape conditions in the region. Several thousand observed feature locations of active layer detachment slides and retrogressive thaw slumps were then used to examine region-wide terrain suitability based on terrain properties including: surficial geology, topography, geomorphology, vegetation and hydrology. Structural equation modeling and integrated terrain unit analyses confirmed and identified the nature and relative strength of relationships among terrain factors explaining observed feature distribution. These results may partially correspond with permafrost ground ice conditions as well, which is further supported by our ordination results. Analysis results drove mapped estimates of terrain suitability for active layer detachment slides and retrogressive thaw slumps across the region, enabling better estimates of permafrost carbon vulnerable to release, and ecosystems potentially impacted by these modes of permafrost degradation. Up to 57% of the study region may contain 'suitable' terrain for one or both of these features. Results support a 'state factor' approach as a useful organizing framework for assessing and describing terrain suitability, and for examining drivers of permafrost characteristics.
    • Retrospective Analysis Of Marine Biological Data From Port Valdez, Alaska: A Case Study In Long -Term Monitoring

      Blanchard, Arny L.; Fedev, Howard (2006)
      Efforts to understand anthropogenic effects within the Port Valdez study area provide a simple and adaptive model for developing and refining hypotheses to measure the structure of and detect, change in nearshore and benthic habitats. Drivers of change detected by this study are the 1964 Prince William Sound earthquake and the oil transportation and salmon aquaculture industries within the fjord. The study area is a glacial-outwash fjord characterized by strong seasonal and spatial environmental gradients due to glacial influences including seasonally low salinity, high suspended sediment loads, and subsequent high sedimentation rates. Direct and indirect effects from intolerance to low salinity are important in organizing intertidal communities as is habitat structure. Previously unrecognized subtle effects on subtidal fauna from anthropogenic stressors near the marine oil terminal in Port Valdez are identified. Demonstration of statistical methods (variogram estimation, repeated measures analysis of variance, and geostatistical modeling) for field studies with spatially and temporally correlated data should be useful to others seeking to establish new long-term studies or analyze previously collected, long-term field data. Investigation of the re-adjustment of benthic fauna from a large earthquake and ecosystem-level effects of salmon aquaculture are not readily available and this dissertation provides a reference point for any such future studies. Although re-adjustment from the large earthquake was a key process during the study period, salmon aquaculture appears to have a strong effect on the benthic ecosystem. The model of detecting change is simple and adaptive and provides inputs for larger models and scientific investigations in marine ecosystems. Broad questions are developed through a long-term study of an ecosystem. The hypotheses formulated are then evaluated and refined through retrospective analysis of long-term data and results can be used to refine larger models. This dissertation contributes rigorous, statistically bounded biological time series to regional monitoring programs by providing small-scale, ecological information necessary for larger models. As a result, the information provided in this dissertation should increase the accuracy of ecological models and aid in the management of marine resources.
    • Retrospective analysis on the effects of bottom trawl fishing in the Gulf of Alaska and Aleutian islands

      Coon, Catherine (2006-05)
      Commercial bottom trawl fishing effort during 1990-2000 was summarized for the Gulf of Alaska and Aleutian Islands to determine spatial and temporal patterns of fishing effort. Attributes of the benthic community based on research bottom trawl surveys were compared between areas of high and low commercial bottom trawling effort. The total number of bottom trawl tows was estimated to be 133,326 for the Gulf of Alaska, and 47,483 for the Aleutian Islands. For the Gulf of Alaska, the 301-500 m depth range of the Kodiak area had the highest density of bottom trawl tows for the decade with 2.039 trawl tows/km². For the Aleutian Islands, the 101-200 m depth range of the eastern Aleutian area had the highest density of bottom trawls with 1.447 trawl tows/km² in an area of 7,909 km². Fish abundance, fish species richness, and invertebrate biomass differed significantly among locations but did not differ between the two levels of trawl effort. A significant interaction between trawl effort and location indicated that differences in biomass of fish species between levels of trawl effort depended on location. Species composition appeared to be more related to location than to levels of trawl effort.
    • A retrospective assessment of primary productivity on the Bering and Chukchi Sea shelves using stable isotope ratios in seabirds

      Abromaitis, Grace Elizabeth; Schell, Donald; Castellini, Michael; Springer, Alan (2000-12)
      Recent declines of marine mammal seabird populations in the Bering Sea have raised the question of whether the changes are caused by fishing pressure or a decrease in ecosystem carrying capacity. Stable carbon (¹³C⁾ and nitrogen (¹⁵N⁾ isotope ratios in Thick⁻billed Murre muscle and feathers were used as indicators of changing seasonal primary production. ¹³C values in phytoplankton vary directly with growth rates and are passed up the food web to consumers. Muscle and feather ¹³C values decreased over the period 1976-1998 suggesting a decline in Bering/Chukchi continental shelf primary production. Carbon isotope ratios in murres were correlated with bowhead whale baleen isotope ratios and to some climate indices. In contrast, ¹⁵N values in the birds showed no significant change indicating no concurrent shifts in trophic status.
    • Returning: Twentieth century performances of the King Island Wolf Dance

      Kingston, Deanna Marie; Morrow, Phyllis (1999)
      In 1982 and again in 1991, the King Island (Alaska) Native Community revived the Wolf Dance, which is a complex ritual involving songs, dances, feasts, competitive games and an exchange of goods. The object of this dissertation is to discover why they chose to revive the Wolf Dance, rather than the Polar Bear Dance which was their most significant ritual in the early twentieth century. Archival sources and other literature pertaining to Inupiaq and Yup'ik ceremonialism were consulted in order to interpret the meaning and purpose of the Wolf Dance. In addition, contemporary King Island community members were interviewed in order to obtain their interpretations. Videotapes of both the 1982 and 1991 performances were viewed in order to gain information not obtained in either written or oral sources. Finally, archival sources were again searched to understand the interactions between King Islanders and members of Western society, including missionaries, tourists, public folklorists, and agents of the Bureau of Indian Affairs. This dissertation concludes that the Wolf Dance was revived for reasons that served both individuals and the community. Organizers of Wolf Dance performances desired to enact either their own or a family member's return to the community. The King Island community performed the Wolf Dance either to create peace or to encourage youth to return to traditional activities. Although particular meanings of the Wolf Dance changed through time, the basic themes of the Wolf Dance (returning, reciprocity, friendship/enmity, and danger) were maintained in contemporary performances. Finally, because the Wolf Dance embodied the cultural value placed on balancing, rather than resolving, tensions and contradictions, this ritual mirrors their perceived need to balance traditions with new influences of Western society. Catholicism was balanced with traditional beliefs, the use of Western resources (such as funding) was balanced with the need to counteract Western forces, and the need to be interdependent with mainland Natives was balanced with their need to be separate from them. Thus, the Wolf Dance reflects not only basic themes of their social order, but also their history of interaction with Western society.
    • Reversability Of Arctic Sea Ice Retreat - A Conceptual Multi-Scale Modeling Approach

      Mueller-Stoffels, Marc; Wackerbauer, Renate (2012)
      The ice-albedo feedback has been identified as an important factor in the decay of the Arctic sea ice cover in a warming climate. Mechanisms of transition from perennial ice cover to seasonal ice cover are discussed in the literature; the existence of a tipping point is disputed. A newly developed regular network model for energy exchange and phase transition of an ice covered ocean mixed layer is introduced. The existence of bistability, a key ingredient for irreversibility, on local and regional scales is explored. It is shown in a spatially confined model that the asymptotic behavior and the existence of a parameter region of bistability strongly depend on the albedo parametrization. The spatial dynamics of sea ice retreat are studied for a high resolution latitudinal model of the ocean mixed layer. This regional model suggests that sea ice retreat is reversible. It is shown that laterally driven melt of thick multi-year sea ice, and thus, ice-albedo feedback, is an important mechanism in the transition from perennial to seasonal ice cover at the pole. Results are used to interpret observed changes in the recent ice extent and ice volume record. It is shown that the effectiveness of ice-albedo feedback strongly depends on the existence of lateral heat transfer mechanisms in the ocean.