Recent Submissions

  • The effect of Siberian alder on the activities of three extracellular enzymes and their implications for soil decomposition in Arctic and boreal Alaska

    Heslop, Calvin; Ruess, Roger; Bret-Harte, Syndonia; Kielland, Knut (2020-08)
    As tall shrubs increase in extent and abundance in response to a changing climate, they have the potential to substantially alter ecosystem nutrient availability and carbon (C) balance. Siberian alder (Alnus viridis ssp. fruticosa), a nitrogen (N) fixing shrub, is among the species responding to climate warming in both the Arctic and boreal forests. Alder-fixed N has the potential to increase decomposition of labile C, by relieving N limitation on microbial activity. Simultaneously, it has the potential to decrease decomposition of recalcitrant C by downregulating microbial N mining. The net effect of N additions is influenced by the relative quality of the soil C and could determine whether alder N additions result in a net sink or source of C to the atmosphere. We measured the activities of three extracellular enzymes in bulk organic soils under and away from alder canopies, in stands differing in soil organic matter quality, in both arctic and boreal forest regions of Alaska, USA. In the Alaskan arctic, the proximity of alder increased the activities of both recalcitrant and labile C-degrading enzymes regardless of soil C quality, potentially resulting in increased C losses. In the boreal forest, enzyme activities did not differ with alder proximity nor stand soil C quality, possibly due to long legacies of alder N inputs relieving microbial N limitation in these stands. As arctic and boreal forest ecosystems experience shifts in the distribution and abundance of this N fixing shrub, alders' influence on soil decomposition could have significant consequences for high latitude soil C budgets.
  • Beyond trending: using risking connection as a framework for moving agency culture toward trauma-informed care

    Healey, Michael J.; Renes, Susan L.; Strange, Anthony; Baker, Courtney; Anahita, Sine (2020-08)
    The prevalence and pervasive impact of adverse childhood experiences (ACEs), and more broadly, trauma, are well supported in the extant literature. Despite this evidence, there remains a significant dearth of formal training and educational programs that prepare staff who work with trauma survivors within complex behavioral health systems. Trauma-informed care (TIC) has moved beyond a trend in the mental health field and is gaining momentum as a leading philosophical paradigm that is being infused as an operational framework for agencies that work with survivors. Risking Connection (RC) is a curriculum-based training program that works with agencies interested in becoming trauma-informed. The current study examined the impact of RC on trainee outcomes for knowledge gain, attitude change, and vicarious trauma (VT) on 119 participants who all work for a therapeutic group home system being operated by a provincial government in Atlantic Canada. The findings in this study suggest that RC is effective in improving knowledge gain and attitude change in a favorable direction toward TIC. The study also supported previous findings associated with the improvement of VT.
  • Community composition and biogeography of beetles and spiders across an elevational gradient in Denali National Park, Alaska

    Haberski, Adam; Sikes, Derek S.; Hollingsworth, Teresa; Armbruster, W. Scott (2020-08)
    Anthropogenic climate change is rapidly altering alpine ecosystems in Alaska. Trees and woody shrubs are expanding upslope and displacing alpine tundra. As alpine tundra habitats shrink and fragment, arthropods and other animals face an increased risk of extirpation due to smaller population sizes and reduced geneflow. Arthropods--insects, spiders, and their relatives--are the most speciose component of the alpine fauna and perform key ecosystem services, such as pollination and nutrient cycling, and are food for vertebrates. Many species have responded by shifting their distribution to higher elevations, but species respond to change idiosyncratically, which could alter species interactions and disrupt communities. I compared beetle and spider communities along an elevational gradient in Denali National Park and Preserve, Alaska, an area with a complex biogeographic history and a poorly known arthropod fauna, in order to 1) examine differences in diversity, abundance, and community composition among forest, shrub, and alpine tundra habitats; 2) link the observed differences to abiotic factors relevant to climate change; and 3) test if shared habitat preferences lead to community-level patterns in geographic distribution. After three consecutive summers of sampling, I found that alpine tundra supports an unexpectedly diverse arthropod community with a high proportion of unique species and that vegetation cover and mean air temperature are strongly correlated with community composition. I therefore expect species losses among alpine tundra communities as shrubification continues. Community-level distribution patterns were not observed, but trends in the data point to a reduction of Holarctic distributions among forest-dwelling arthropods and an increased proportion of Beringian endemics among tundra species. This was the first systematic survey of Denali's terrestrial arthropods and added over 450 new park records.
  • Impacts of climate change on juvenile broad whitefish Coregonus nasus in Arctic Alaska: bioenergetics model development and application

    Green, Duncan G.; Sutton, Trent M.; Norcross, Brenda L.; Cunningham, Curry J. (2020-08)
    Anthropogenic climate change is contributing to rising temperatures worldwide, yet the increase is particularly rapid in the Arctic. Despite their position on the front of global temperature warming, the responses of Arctic ecosystems and the individual species within them are poorly understood. Broad whitefish Coregonus nasus in the Alaska nearshore Beaufort Sea not only inhabit a rapidly changing ecosystem, but are also a key component of subsistence harvest in the region and a relatively understudied fish. I parameterized and corroborated a bioenergetics model through species-specific physiological investigation and laboratory rearing trials, and used the resulting model to simulate potential responses in growth and consumption under climate change scenarios projected with global climate models. Simulations at current estimated prey energy densities projected increases in future consumption rates of up to 4% required to maintain historically observed summer growth, while simulations in which prey energy density was reduced by 50% resulted in projected consumption increases of up to 107% necessary to maintain historic growth. Simulations in which prey energy density was increased by 50% indicated the ability for juvenile broad whitefish to reduce consumption rates by up to 32% and maintain current growth rates. These results suggest that, although the physiological effects of rising water temperatures have the potential to increase growth rates of juvenile broad whitefish, climate-induced shifts in prey availability or prey quality are likely to be regulating factors that determine the magnitude and direction of changes in growth rates.
  • Fate and effects of commercial crude oil bioremediation products in Arctic seawater

    Gofstein, Taylor R.; Leigh, Mary Beth; Simpson, William; Guerard, Jennifer; Collins, R. Eric (2020-08)
    With increased oil exploration, development, and transport in the Arctic in recent years, the potential for disastrous oil spills is imminent. Biodegradation, the consumption of contaminants by indigenous microorganisms capable of using them as an energy source, can be enhanced using bioremediation treatments and may be a viable spill remediation method when traditional physical recovery techniques are not. The EPA National Contingency Plan (NCP) product schedule lists oil spill response treatments that can be used in the event of a spill, many of which can stimulate intrinsic biodegradation. However, there is often little to no experimental data demonstrating the effectiveness of these products in aiding the remediation of a spill. Here we investigate the effects of the currently listed NCP products Corexit 9500 and Oil Spill Eater II (OSEII) on crude oil biodegradation in Arctic seawater and the associated shifts in the microbial community using mesocosm incubations. Despite conflicting reports in the literature, Corexit 9500 showed no inhibitory effects on the biodegradation of crude oil. When oil and Corexit were co-present, chemical and microbial data revealed a sequential degradation beginning with the non-ionic surfactant components of Corexit (Span 80, Tween 80, Tween 85), followed by the degradation of the labile alkane oil components, with the degradation of other Corexit components such as dioctyl sodium sulfosuccinate (DOSS) and dipropylene glycol n-butyl ether (DGBE) less clear. 16S rRNA gene sequencing revealed that oil and Corexit stimulate different microbial communities but some taxa are stimulated by either (Oleispira, Pseudofulvibacter, Roseobacter), suggesting that these organisms may be capable of degrading both. Further analysis with metatranscriptomic sequencing showed increased gene expression in the presence of Corexit, even when co-present with oil, suggesting that Corexit may enhance the metabolic activity of oil degraders. Increased expression of β-oxidation pathway genes (fadE, fadA, fadB) in the presence of Corexit coincided with the chemical loss of Corexit components. Based on these findings and the abundance of ester groups in the chemical structures of Corexit 9500 surfactant components, we propose a biodegradation pathway that involves the transformation of ester groups into fatty acids either through biotic lipase enzymes or abiotic hydrolysis, before funneling into the β-oxidation fatty acid degradation pathway. Taxonomic origins for these transcripts showed a diverse number of genera expressing these genes, which along with its lability may serve to explain the number of taxa observed to respond to Corexit both here and in the literature. Characterization of the contents of OSEII revealed the presence of sugars, surfactants, nutrients, phytochemicals, amylase, protease, and the non-hydrocarbonoclastic non-viable microorganisms Lactobacillus and Saccharomyces. Incubation experiments targeting the efficacy of OSEII showed a slight enhancement of n-alkane loss at 30 days, suggesting that it may have utility in longer term use following a post-spill nutrient depletion. However, the nutrient contents of OSEII were up to 32-fold times higher for ammonia and 100,000-fold times higher for iron than in ambient Arctic seawater, which although are limiting nutrients in seawater, may also cause more harmful ecological effects following a spill by inducing phytoplankton blooms. Based on these findings, the non-ionic surfactants of Corexit 9500 appear to be easily degraded through the proposed β-oxidation fatty acid pathway. Future NCP dispersants should target these labile ester chemical moieties while also being effective at dispersion. It is imperative for NCP products to undergo more rigorous third-party experiments to demonstrate their suitability, effectiveness, toxicity, and unintended side effects that may occur in situ before an oil spill occurs. Doing so will allow decision-makers to have comprehensive information to aid in selection of appropriate oil spill response techniques.
  • Bristol Bay dual permit operations, vessel heterogeneity, and the migration of Alaskan permit holders

    Gho, Marcus J.; Criddle, Keith; Adkison, Milo; Adkison, Milo; Twomley, Bruce; Brown, Benjamin (2020-08)
    This dissertation examines three aspects of Alaska's Limited Entry program. Chapter 1 explores the outcome of dual-permit regulations. The Alaska Board of Fisheries passed regulations allowing for dual permit operations in the Bristol Bay Pacific salmon drift gillnet fishery starting in 2004. These regulations allow two permit holders to fish from a single vessel with additional gear. Policymakers anticipated that the dual permit regulations would encourage young fishermen to enter the fishery and reduce the number of limited entry permits transferred from local fishermen to nonlocal fishermen and nonresidents. Statistical analyses reported in Chapter 1 indicate that the dual-permit program successfully offset part of the adverse influence of increases in the market value of permits on the number of new entrants and that implementation of dual-permit regulations was followed by a reduction in the median age of new entrants, particularly among nonresidents. However, the implementation of dual-permit regulation failed to staunch the outflow of limited entry permits. Chapter 2 examines the persistence of heterogeneity in the size of fishing vessels active in the Bristol Bay salmon drift gillnet fishery. When entry was limited, the commercial fishing fleet included a mix of vessels up to the long-established 32-foot maximum length. The race for fish that so often arises under license limitation favors the adoption of vessel and gear configurations that maximize catch-perday and could be anticipated to lead to increased homogeneity in fleet composition. Yet, statistical analyses indicate that even after over four decades, the composition of this fleet remains heterogeneous in vessel size and vessel value. Multivariate analysis of time series observations of vessel values indicates that vessels captained by permit holders who were given their permit are less capitalized than vessels captained by permit holders who purchased their permit. Likewise, vessels operated by local resident permit holders are less capitalized than vessels owned by nonlocal Alaskan or nonresident permit holders. In addition, vessels operated by older permit holders are less capitalized than vessels operated by younger permit holders. Chapter 3 examines the factors that influence the migration of permit holders. Since limitation, there have been concerns that ever more of the permits issued to individuals local to Alaska's fisheries would come to be held by individuals who were not local to the fisheries. The count of permit holders local to a fishery can change because of transfers, administrative cancellations, or because permit holders migrate either to or from fisheries where the permit is used. Chapter 3 considers possible factors that predict permit migration to or from different residency classes. Included in our analysis was a look at season length, fleet participation rates, permit transfers, the size of the fleet, gear type, wages of construction workers to serve as a proxy for substitute employment, and the local unemployment rate. Statistical analyses indicate that fisheries with longer seasons show slightly elevated migration from local to nonresident status of permit holders. Permit latency and permit holder migration have a negative relationship among the significant variables. Transfers serve as a substitute for permit migrations and provide the largest influence on permit migrations. For every resident type of migration, as the transfer rate increases, fewer permit holders migrate. The total number of permits within the fishery also affects the migration of permit holders, albeit only minimally. The second-largest influence on permit migration is gear type. Migrations to local setnet permit holders had a smaller magnitude of change than migrations from permit holders across most categories. Generally speaking, migration tends to move towards a nonresident status of permit holders. Wages of construction workers were only significant at the 5% level for transfers from locals to nonresidents and from nonresidents to locals, but both variables were positive. As the local unemployment rate increases, the rate of locals emigrating outside of Alaska increased.
  • Age, growth, and movement dynamics of Arctic cod (Boreogadus saida) in the Chukchi and Beaufort seas

    Frothingham, Alyssa; Norcross, Brenda L.; Seitz, Andrew C.; Brown, Randy J. (2020-08)
    Arctic Cod (Boreogadus saida) dominates fish assemblages in the Arctic and provides a valuable food source to upper trophic level predators. Little is known about several important facets of its biology and ecology in the Pacific Arctic, including in the Chukchi and Beaufort seas. The physical connectivity of these two biologically and hydrologically unique seas provides an excellent opportunity to explore differences in Arctic Cod life history characteristics such as age, growth, and movement dynamics in these two adjacent areas. To establish a current benchmark of Arctic Cod life history and movement characteristics for the Pacific Arctic, Arctic Cod otoliths collected from 2009 to 2014 during twelve research cruises conducted throughout the Chukchi and Beaufort seas were used to estimate growth and age structure for this species from the two regions. Ages of Arctic Cod ranged from 0 to 5 years with significant overlap in size at age. Growth of Arctic Cod collected in the southern Chukchi Sea and eastern Beaufort Sea regions were similar, suggesting freshwater-influenced regions may enhance growth compared to other areas. Additionally, microchemistry of age-0 Arctic Cod otoliths was analyzed to determine potential differences in elemental signatures between the Chukchi and Beaufort seas, and to infer movement between them. Otolith trace element concentrations were distinct between the Chukchi and Beaufort seas, indicating populations of Arctic Cod from the Chukchi and Beaufort seas can be differentiated based on otolith elemental signatures. Furthermore, elemental signatures from the cores of otoliths were significantly different from those from the edges in both seas suggesting early life history movement. As the Pacific Arctic faces warming sea temperatures and sea ice reduction, predicting a species-level adaptation to a changing environment is nearly impossible without establishing a benchmark for future comparison. This research will provide valuable insight into Arctic Cod across a broad portion of its distribution.
  • Design, manufacture, and testing of a modular array for three-dimensional photovoltaics

    Fiscus, Trevar; Peterson, Rorik; Huang, Daisy; Denkenberger, David (2020-08)
    The emerging technology of three-dimensional photovoltaics is explored, shedding light on past research, current developments, and recommendations for future work. Research was performed at the University of Alaska Fairbanks analyzing six different geometric configurations of solar cells, both computationally and experimentally. The primary work described in this paper is the design and production of a modular solar array prototype and the experimental setup used to test the power output of the different configurations. Data collected from hundreds of tests were processed and analyzed to find optimum configuration angles and recommendations for future research. Working through the process of designing and manufacturing the equipment, and then subsequently using it for experimentation, provided many insights into recommended improvements. This text is organized into eight chapters that detail the background of research in using three-dimensional space for solar power generation, the recent project completed at the University of Alaska Fairbanks, and the proposed guidance for future work on this topic. This paper and use of the sources cited herein should provide the reader with the background and tools necessary to continue research. The latter chapters should act as a guide for the future design of components to be used in laboratory experimentation. It is hoped that this report, the collected data, and associated files from this project will add to the knowledge base of threedimensional solar arrays and help advance the technology one step closer to real-world application.
  • Transport of CH₄ through open-talik lakes in discontinuous permafrost aquifers

    Eckhardt, Bridget A.; Barnes, David L.; Daanen, Ronald P.; Liljedahl, Anna K.; Romanovsky, Vladimir E.; Anthony, Katey Walter (2020-08)
    As northern regions of the world experience warming climate, scientists look to permafrost, a crucial component of Arctic and subarctic ecosystems, as a source and sink of atmospheric carbon. It is well-known that the thawing of permafrost from above as a result of warming climate is a considerable source of greenhouse gases. However, few studies have considered the production of methane, a potent greenhouse gas, beneath the permafrost. A rugged permafrost bottom is proposed to favor the storage of gas in "pockets" that have been formed through permafrost thaw and degradation from below. Sub (below)-permafrost methane can migrate to reach the atmosphere when connections between the sub-permafrost and supra- permafrost open pathways from the pocket to the bottom of an open talik lake. We hypothesized that the migration of methane occurs through advection and diffusion as a dissolved gas and by movement as an immiscible fluid. Through measurement of environmental tracers in two thermokarst lakes in Goldstream Creek Basin, Fairbanks, Alaska, we found that advection was variable and was seasonally and climatically dependent demonstrating both upward and downward groundwater flow within our study lakes. Measurements of dissolved methane concentrations in the lakes demonstrated that diffusion of methane was not a significant transport mechanism in the groundwater-to-lake pathway due to the extreme temporal and spatial variability of methane concentrations. Immiscible flow of free-phase methane is likely the dominant transport mechanism but is dependent on the lake sediment composition and the formation of secondary pathways within the talik. Data obtained from this study allowed for a better understanding of methane transport and thermokarst lake dynamics.
  • Temporal and size-based patterns in juvenile sablefish energy allocation and diet

    Callahan, Matthew W.; Beaudreau, Anne H.; Mueter, Franz J.; Heintz, Ronald A. (2020-08)
    A recent marine heatwave in the Gulf of Alaska caused depressed growth, poor body condition, and low survival in many fish species, but juvenile sablefish (Anoplopoma fimbria) thrived. These fast-growing piscivores are the target of a valuable commercial fishery in Alaska as adults and have historically shown high variability in recruitment. The first winter is a period of nutritional stress and high mortality for many fish species and first winter survival may dictate year class strength, but the importance of the first winter for juvenile sablefish is understudied. We examined juvenile sablefish energy storage, growth, and diet during their first two years of life, specifically as newly settled juveniles in their first autumn, in late winter, and during their second summer and autumn. Sablefish grew rapidly in autumn and growth slowed but continued through winter. Mean energy density (kJ g⁻¹) declined over the winter but total energy (kJ individual⁻¹) increased significantly between October and March. Slopes of energy density and total energy versus length regressions were atypical for high latitude marine fish in that they were steepest in March. This indicates that large fish grew during winter with minimal energy depletion while small fish grew but depleted their energy stores. Stable isotope results revealed that larger fish were enriched in [delta]¹³C and [delta]⁻¹⁵N in March relative to smaller fish, suggesting diet differences may contribute to size-specific energy storage patterns during winter. Pacific herring (Clupea pallasii) dominated diets but consumption of herring and other prey varied seasonally and annually. Relative stomach content weights were highest in autumn 2018, which was a period of rapid growth. Results of this study show advantages for sablefish achieving large size prior to winter and broadly support the hypothesis that first winter is a life history bottleneck for juvenile sablefish. The generalist feeding strategy of sablefish and rapid growth early in life may provide the ability to adapt to a wide range of environmental conditions.
  • If women were dragons: a study of the conquest of women and dragons in Ragnar's saga, the Volsunga sagas, and the Nibelungenlied

    Baalke, Claire-Elise A.; Harney, Eileen; Stanley, Sarah; Riley, Terry (2020-08)
    This thesis is a study displaying the connections between female characters and dragons in Old Norse and Middle High Germanic literature. The main associations that I examine are the ways that female characters and dragons share the characteristics of greed or hoarding, prophetic sight or supernatural power, and "monstrosity" or "Otherness." The fundamental argument is that the women and dragons have common characteristics which define them as dangerous and thereby cause the men or heroes of the tale to feel the need to silence or depower them through conquest. Typically, the dragon is the barrier between the woman and the hero in these kinds of stories and thus the dragon is violated or slain in a manner that represents quashing of feminine power. I argue that the dragon is defeated as proxy to the defamation or depowering of deviant female characters, non-conforming women who do not follow socially accepted gender roles. The texts used to present these arguments are The Poetic Edda, The Volsunga Sagas and its prequel Ragnar's Saga, and The Nibelungenlied. In the majority of dragon stories there is a direct relationship between a dragon and a female character, commonly a princess who is being protected or arguably kept captive by the dragon. I argue, however, that these characteristics of the dragon, which are imitated by female characters, can manifest metaphorically as well. In the texts considered in which there are no "real" or physical dragons, a woman stands in as the metaphorical dragon that must be defeated.