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Recent Submissions

  • Climate change, moose, and subsistence harvest in Arctic Alaska

    Zhou, Jiake; Kielland, Knut; Kofinas, Gary; Tape, Ken D.; Prugh, Laura (2020-08)
    Arctic climate is resulting in transformative changes to Arctic social-ecological systems. With warming-induced increases in tall-shrubs, moose are expanding their range northwards. However, the socio-economic implications of this ecological change are unclear. Using field surveys, interviews, and modeling, I assessed the impact of climate change on moose harvest by hunters of Nuiqsut, an Inupiat community in arctic Alaska. Based on a 568 km transect of field sampling on shrubs and herbivore browsing levels, I estimated that the minimum shrub height for moose occurrence was ≥ 81 cm (95% CI: 65 - 96 cm). Patterns of moose geographic distribution mirrored tall-shrub distribution in arctic riparian areas. I also found that snowshoe hares may impact moose habitat via potential resource competition. Habitat suitability models, using Maxent and simpler temperature-threshold models, predicted that moose habitat may more than double by 2099 if current warming trends continue. The model outputs also suggested that climate warming will likely increase habitat connectivity, enhancing range expansion of moose in the Arctic. Finally, I used a coupled social-ecological systems (SES) framework to assess the implications of changes in tall-shrub habitat to moose harvest under future warming. Despite the expected increase in moose habitat and distribution, simulations of an agent-based model showed that the future may not translate into greater harvest opportunities, largely due to the limitation of river navigability for hunters. These findings provide an example in which rapid landscape and resource change may not translate into increased harvest. The integrated assessment with a SES framework revealed new and surprising outcomes, not evident when evaluating social and ecological components separately. This analysis highlighted how a coupled social-ecological framework can be used to assess the effects of climate change on ecosystem services.
  • Sea urchin ecology: effects of food-web modification, climate change, and community structure

    Weitzman, Benjamin P.; Esler, Daniel; Konar, Brenda H.; Hardy, Sarah M.; Johnson, Mark A.; Tinker, Martin T. (2020-08)
    Ecosystem structure and function of temperate rocky reef habitats are subject to change as a result of food-web modification, climate change, and changes in biological community interactions. Sea urchins are a global driver of change in nearshore marine habitats though their ability to heavily graze marine vegetation and force rocky reef ecosystems from kelp forest to sea urchin barren ground states. The Aleutian Archipelago in southwest Alaska provided an ideal natural laboratory to study sea urchin (Strongylocentrotus spp.) ecology following the functional loss of the keystone predator, the sea otter (Enhydra lutris) during the 1990s. The objectives of this dissertation were to 1) determine the important drivers of sea urchin demographics following the functional loss of their keystone predator; 2) determine how projected ocean warming and acidification may affect sea urchin physical condition; and 3) identify biological drivers of sea urchin recruitment in both kelp forest and barren ground habitats. To determine demographic drivers, I used a time series of benthic habitat, sea urchin demographic, and environmental data, dating back almost forty years. In the absence of sea otters, environmental conditions, specifically ocean temperatures, became more important to sea urchin demographics, but recruitment was the primary process affecting the resultant abundance and size class structure over time. To understand how predicted ocean warming and acidification could impact S. polyacanthus survival, growth, calcification, gonad development, and energy content, a 108-day laboratory experiment was conducted. This experiment determined that temperature caused a greater reduction in survival than acidification, and that projected changes in temperature and acidification will result in investment trade-offs between reproduction and maintenance or growth of somatic and calcified tissues. To determine how recruitment varied between kelp forest and sea urchin habitats, fine-scale surveys of benthic community structure found that specific taxa, and not overall community structure, correlated with sea urchin recruitment. Results from this dissertation will allow managers to make predictions about how sea urchin demography will change as a result of keystone predator loss and climate change and how that will affect nearshore community structure and function. Overall, my dissertation establishes likely pathways by which coastal habitats may change over time, in a system no longer under strong top-down control.
  • In pursuit of harm reduction in the Alaskan context: patient cultural explanatory models of addiction and treatment outcomes for a medically-assisted program utilizing a buprenorphine/naloxone formulation

    Vasquez, Ángel R.; Campbell, Kendra; Lopez, Ellen; Gifford, Valerie; Gonzalez, Vivian (2020-08)
    This study explored the process of completing a private-for-profit medically-assisted treatment (MAT) program which treats opioid use disorder in a semi-rural community in Alaska. The goal of the study was to answer two broad research questions: (a) did patients get better during the medically-assisted treatment program, and (b) what characterized patient experiences participating in the MAT program? Limited research has been conducted to understand patient experiences of completing medically-assisted treatment in small communities and how various factors may impact treatment outcomes and recovery trajectories. To achieve this goal, a mixed methods case study approach was conducted to evaluate changes in symptom distress and characterize the experience of patients who participated in the program. Three Phases were implemented. Phase I involved archival data analysis of a 22 patient dataset was conducted to assess pre-post treatment outcomes. In Phase II three participants were interviewed who initiated in the program to explore patient treatment themes. Phase III involved co-interpretation of preliminary findings MAT program providers to synthesize findings and gain insights into systemic factors that may have impacted participant experiences. The three-phase research study revealed three major findings. First, MAT patient program completers in our sample who utilized buprenorphine/naloxone in conjunction with counseling experienced a statistically significant reduction in psychological distress with a large observed effect size (Phase I). Second, themes that emerged from semi-structured interviews suggest motivation and treatment process factors play an important role in treatment success (Phase II). Finally, community stakeholders on the provider treatment team were consulted to more deeply understand why it is important to assess patient needs and co-interpret key study findings (Phase III).
  • Trophic structure of rocky intertidal communities in contrasting high-latitude environments

    Siegert, Danielle; Iken, Katrin; Konar, Brenda; Lindeberg, Mandy (2020-08)
    Coastal ecosystems in high latitudes are increasingly impacted by glacial melt and river discharge due to climate change. One way to understand ecosystem responses to these stressors is assessing trophic relationships. The goal of this study was to better understand how hydrographic conditions influence trophic structure in high-latitude rocky intertidal systems. I compared the trophic structure of rocky intertidal assemblages in two regions in the northern Gulf of Alaska that comprise the same regional species pool but are hydrographically distinct, one glacially influenced and one primarily marine influenced. Common macroalgal and invertebrate taxa, as well as particulate organic matter (POM) were sampled at three rocky intertidal communities in each region in 2017 and 2018. Food web structure was compared using trophic metrics based on the distribution of shared taxa in isotopically-derived (delta¹³C and delta¹⁵N) trophic niche space. I found that trophic niche space in the glacially-influenced rocky intertidal system was larger, driven by larger ranges in both carbon and nitrogen stable isotope values. In particular, the lower delta¹³C values in Kamishak Bay suggest that an additional food source, most likely terrestrial organic material from glacial discharge, was incorporated into the food web. This supported the hypothesis that patterns in food web structure differed based on hydrographic influences to maintain overall stability. Isotopic evenness, i.e., the distribution of the shared taxa within trophic space, did not differ between the two regions. Macroalgae were overall a more important food source than POM in both regions, and even more so in the glacially-influenced region, where macroalgae may be an energetically beneficial food source compared to silt-laden glacial inputs. This study showed that common intertidal taxa have high tropic flexibility enabling them to respond to variable food sources under a variety of environmental conditions. As hypothesized, taxa in food webs occupying a larger trophic niche space engaged in more heterogeneous trophic pathways and used diverse resources depending on local environmental conditions, making these systems more stable to perturbations affecting a single resource. The common taxa of high-latitude rocky intertidal systems studied here are responding to current levels of glacial input with more diverse resource use, but it remains to be seen how well those systems are suited to maintain trophic stability with an expected increase in glacial stress from climate warming.
  • Safety analysis of off-highway vehicles use within public rights-of-way in Alaska

    Sayre, Tristan; Belz, Nathan; Barnes, David; Falchetto, Augusto (2020-08)
    Many Alaskans own and operate off-highway vehicles (OHVs) for recreational purposes or for use as primary and secondary modes of transportation. However, the reported crash rate shows that 80 on-road crashes, resulting in five fatalities, occur each year statewide. As a result, the use of OHVs has been identified as a safety concern in the Alaska State Highway Safety Improvement Plan. Minimal research dedicated to understanding OHV use in Alaska exists which limits the potential for improvements that address safety concerns in an equitable fashion. The research presented here contributes to better understanding of on-road OHV use through observational and retrospective analysis. Field-based observations were conducted within highway rights-of-way in 14 strategic locations across Alaska to quantify OHV use and the risk-taking behaviors of riding without helmets, passengers riding without a designated seat, and riding unlawfully on the road. Additional risk factors from the field observations and Alaska Department of Motor Vehicles (DMV) crash data for the period from 2000 through 2016 were identified using the Chi-Square test for independence. Spatial analysis of the Alaska DMV crash data for the period from 2009 through 2016 tested for complete spatial randomness of crashes and identified clusters of crashes by frequency and severity using neighborhood point density statistics. Frequent OHV use was observed with daily traffic volumes exceeding 40 vehicles per day in three field study locations. Several risk-tolerant behaviors were observed including users riding without helmets and vehicles carrying passengers without a designated seat an average of 70 and 20 percent of the time, respectively. Additionally, over half the OHV users were observed to be riding unlawfully using the road. Risk-tolerant behaviors were most frequently observed in communities where on-road use is legal and happened to be coincident with the highest on-road use rates. Overrepresented risk factors for high crash severity incidents included riding at night, in summer, on unpaved roads, on local roads or collectors, in rural areas, for single-vehicle crashes with the occupant not using safety equipment and riding under the influence of alcohol. Crashes were observed to be clustered around towns with the highest frequencies occurring near town centers. The prevalence of risk-tolerant riding behaviors and unlawful on-road riding indicates the need for improvements to existing laws and the education and enforcement thereof. Changes must address the unique needs of users while also considering local jurisdiction such that safety can be improved while also maintain transport equity for residents of rural and isolated communities in Alaska.
  • Sea otters in Southeast Alaska: subsistence harvest and ecological effects in seagrass communities

    Raymond, Wendel W.; Eckert, Ginny L.; Beaudreau, Anne H.; Galloway, Aaron W.E.; Mueter, Franz J. (2020-08)
    The recovery of sea otters (Enhydra lutris) to Southeast Alaska is a conservation success story, but their increasing population raises questions about sea otter population dynamics and the ecological role of this top-level predator. In Chapter 1, we addressed these questions by investigating patterns and population effects of subsistence sea otter harvest. Subsistence harvest reduced populations at a small scale, with potential to slow or stop population growth, but across Southeast Alaska the population continues to grow, even with an average 3% subsistence harvest rate. In Chapters 2 and 3 we investigated the ecological role of sea otters in seagrass (Zostera marina) communities. When we tested for generality in a sea otter - seagrass trophic cascade across a large spatial scale in Southeast Alaska, we found a positive relationship between sea otters and seagrass. However, we found no evidence of a relationship between crabs and epifauna, suggesting that the ecological mechanisms in Southeast Alaska may differ from other regions. Our comparison of carbon and nitrogen stable isotopes (SI) to assess the role of sea otters on trophic structure and energetic pathways of seagrass beds found little effect of sea otters in overall community trophic niche space, suggesting similar carbon sources and food chain length in seagrass meadows regardless of sea otters. Conversely, the FA profiles of diverse consumer suggest variation in dietary sources with and without sea otters. This result suggests that the trophic cascade may not be the only or primary energetic pathway in Southeast Alaska seagrass communities. In all, our studies have revealed that sea otters in Southeast Alaska are linked to both people and a common Southeast Alaska nearshore habitat, seagrass. These results describe the varied interactions of a recovering top predator and highlight a need to consider these diverse interactions in resource management, conservation, and ecological research.
  • Life cycles of the kelps Saccharina latissima and Alaria marginata: implications for mariculture and ecology in Alaska

    Raymond, Annie E.T.; Stekoll, Michael S.; Eckert, Ginny L.; Bergstrom, Carolyn A. (2020-08)
    Kelp farming has the potential to economically diversify coastal communities of Alaska while offering other ecosystem services, including carbon sequestration and mitigation of eutrophication. Two bottlenecks to the expansion of the industry are understanding the natural kelp life cycle and manipulating the life cycle to produce seed. We address these questions with specific research aimed to increase knowledge of the expected natural variability of the kelp life cycle and test methods to effectively manipulate storage of kelp seed string to add flexibility to the kelp farming industry. First, in Chapter 1, we documented the patterns of sporophyte fertility for two commercially important kelp species, Saccharina latissima and Alaria marginata, in the wild. We found S. latissima exhibited both annual and perennial life history varying by location and year, with an increasing proportion of fertile sporophytes present in the fall and winter season. In contrast, A. marginata displayed a predictable annual life history, recruiting in spring with the proportion of fertile sporophytes increasing into the fall. Results from Chapter 1 suggest A. marginata has a more reliable brood stock availability and, therefore, has the potential to be a suitable commercial crop. Ecologically, Chapter 1 results suggest A. marginata may contribute consistently to habitat across Alaska in spring and summer months. In Chapter 2, we tested how different culture conditions, including light, temperature, and culture media, affected gametophyte growth with the goal of developing storage methods for kelp seed string. We found that low temperature is effective in slowing gametophyte growth and reducing gametogenesis and is the best condition for seed storage. Further experiments tested how storage in cold temperatures affects seed quality, leading to the development of a method called "cold banking," which enables extended seed storage or staggering of seed string for at least an additional thirty-six days in a storage setting without adverse effects to sporophyte density and length at the time of outplanting and up to three weeks after outplanting. Ecologically, Chapter 2 results demonstrate the diversification of microscopic stages used as an overwintering strategy by S. latissima. As the kelp mariculture industry is expected to grow in Alaska and around the world, we hope this information will be a jumping-off point for research promoting productive and sustainable commercial kelp production.
  • Long-term shifts in community structure, growth, and relative abundance of nearshore Arctic fishes: a response to changing environmental conditions

    Priest, Justin T.; Sutton, Trent M.; Mueter, Franz J.; Raborn, Scott W. (2020-08)
    Environmental conditions influence the presence, species composition, abundance, and growth of fish species in the nearshore Arctic ecosystem. With ongoing shifts in Arctic conditions due to climate change, how fish communities and individual species respond to such changes to environmental variability more broadly is unknown. This study analyzed catch and length data from a long-term fish monitoring project near Prudhoe Bay, Alaska, 2001-2018, to quantify the effects of environmental variables on the overall fish community and on the juveniles of two important whitefishes, Arctic Cisco Coregonus autumnalis and Broad Whitefish Coregonus nasus. Abundance data (n = 1.78 million fish) from daily sampling (July-August) at four stationary sampling locations showed distinct shifts in fish community metrics. Since 2001, annual species richness has significantly increased by one species per decade while water temperature warmed by over 1.4°C. The species composition based on biweekly catch data has significantly changed across years, with distinct variations among sample locations and throughout the season. Species composition was significantly affected by both salinity and water temperature. The effects of environmental conditions on growth showed that water temperature was positively and linearly associated with increases in growth for juvenile whitefish, while salinity negatively affected growth of age-0 Arctic Cisco. Changes in the abundance of juvenile whitefishes were related to both water temperature and salinity. Results from all analyses suggest that species positively associated with observed warming in the aquatic environment are generalist species such as Broad Whitefish. This study concluded that continued climate change, and especially Arctic warming, will likely increase growth, change the species composition, and alter abundance in the Arctic nearshore ecosystem. These changes will have impacts on subsistence harvests and on upper trophic level species that prey on nearshore fishes.
  • Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas

    Poje, Alexandra; Hopcroft, Russ; Coyle, Kenneth; Danielson, Seth (2020-08)
    Egg production and copepodite growth rates were measured for the calanoid copepods Pseudocalanus spp., Calanus marshallae/glacialis, and Metridia pacifica in the northern Bering and southern Chukchi Seas during June of 2017 and 2018. For all taxa, instantaneous growth rates generally decreased with increasing copepodite stage, though the differences between most stages was not significant. The growth rates for Pseudocalanus spp. averaged 0.03 ± 0.002 day⁻¹, Calanus spp. 0.09 ± 0.004 day⁻¹, and M. pacifica 0.05 ± 0.03 day⁻¹. Egg production rates increased with prosome length for all species, but when standardized to body weight this trend reversed. All Pseudocalanus species had similar weight-specific egg production (SEP): 0.18 ± 0.01 for P. acuspes, 0.15 ± 0.00 for P. newmani, and 0.11 ± 0.02 for P. minutus. The SEP for Calanus was considerably lower, 0.09 ± 0.01, while for M. pacifica it was 0.11 ± 0.01. These rates suggest considerable discrepancies between growth rates and egg production weights that we propose are due to differences in life history strategies. Pseudocalanus reproduce nearly year round, they appear to invest less in somatic growth, preferring to quickly reach their adult stage where they invest heavily into reproduction. Calanus spp. have 1 or possibly 2 generations per year in this region, they invest more into somatic growth in order to ensure their population is ready for a reproductive season timed to the spring phytoplankton bloom. The more omnivorous M. pacifica is also likely limited to 1 or 2 generations, although their ability to thrive on a wider range of food sources than Calanus seems to allow for relatively higher investment in reproduction and perhaps lower investment in somatic growth. Consistent with other studies, global growth models do not match our observations particularly well, likely because they are dominated by egg production estimates at lower latitudes.
  • Control of internal transport barriers in magnetically confined tokamak fusion plasmas

    Panta, Soma Raj; Newman, David; Wackerbauer, Renate; Ng, Chung Sang; Sanchez, Raul (2020-07)
    In the Tokamak plasma, for fusion to be possible, we have to maintain a very high temperature and density at the core at the same time keeping them low at the edge to protect the machine. Nature does not favor gradients. Gradients are source of free energy that causes instability. But we require a large gradient to get energy from plasma fusion. We therefore, apply a huge magnetic field on the order of few Tesla (1 T-10 T) that confines the plasma in the core, maintaining gradients. Due to gradients in density of charged particles (ions and electrons), there is an electric field in the plasma. Heat and particle transport takes place from core to edge mainly through anomalous transport while the E x B velocity sheer acts to reduce the transport of heat and particles. The regime at which the E x B velocity shear exceeds the maximum linear instability growth rate, as a result, the transport of particles and heat gets locally reduced is termed as the formation of a transport barrier. This regime can be identified by calculating the transport coefficients in the local region. Sometimes it can be observed in the edge where it is called an edge barrier while if it is near the core it is an internal transport barrier. There is a positive feedback loop between gradients and transport barrier formation. External heating and current drives play an important role to control such barriers. Auxiliary heating like neutral beam injection (NBI) and radio frequency (RF) heating can be used at a proper location (near the core of the plasma) to trigger or (far outside from the core) to destroy those barriers. Barrier control mechanism in the burning plasmas in international thermonuclear test reactor (ITER) parameter scenarios employing fusion power along with auxiliary heating source and pellets are studied. Continuous bombardment with pellets in the interval of a fraction of a second near the core of the burning plasma results in a stronger barrier. Frozen pellets along with auxiliary heating are found to be helpful to control the barriers in the tokamak plasmas. Active control mechanism for transport barriers using pellets and auxiliary heating in one of tokamaks in United States (DIII-D) parameter scenarios are presented in which intrinsic hysteresis is used as a novel control tool. During this process, a small background NBI power near the core assists in maintaining the profile. Finally, a self-sustained control mechanism in the presence of core heating is also explored in Japanese tokamak (JT-60SA) parameter scenarios. Centrally peaked narrow NBI power is mainly absorbed by ions with a smaller fraction by the electrons. Heat exchange between the electron and ion channels and heat conduction in the electron channel are found to be the main processes that govern this self control effect. A strong barrier which is formed in the ion channel is found to play the main role during the profile steepening while the burst after the peaked core density is found to have key role in the profile relaxation.
  • Timescales of magmatic processes from diffusional profiles recorded in minerals of the 2016-2017 eruption of Bogoslof Volcano, Alaska

    Moshrefzadeh, Jamshid Akhbar; Izbekov, Pavel; Loewen, Matthew; Larsen, Jessica; Regan, Sean (2020-08)
    Every volcanic eruption is unique, and creates opportunities for scientists to gain insights on magma processes. Studying active volcanoes not only adds to our understanding of fundamental processes that shape our planet, but it is also importantly aids the scientic community to assess and mitigate the many hazards that volcanoes pose. The products of the 2016-2017 eruption of Bogoslof Volcano provide a unique opportunity for the application of diusion chronometry, due to the abundance of distinct, stepwise boundaries within three mineral phases: clinopyroxene, plagioclase, and amphibole. Given that diusion is driven by the presence of a chemical gradient, the compositionally stepwise boundaries between distinct zones can be used to investigate the diusion of elements within the crystals in order to constrain timing of the magmatic processes that created them, as well as crystal residence times. Here we present our analyses of these stepwise boundaries, and discuss the potential correlation of acquired diusional timescales from clinopyroxene with the other two mineral phases, in order to determine what magma processes lead to the formation of these boundaries, and when these processes occurred. Our results suggest that the stepwise boundaries in crystalline phases of the magmas erupted by Bogoslof in August 2017 formed due to mac recharge that resumed in March 2017 and occurred repeatedly until the cessation of the eruption in August 2017. Activity at Bogoslof during March 2017 is additionally characterized by increased seismicity and SO₂ rates, suggesting that our petrologic results are consistent with multiple interdisciplinary observations.
  • Seasonal variation in nutritional biomarkers and fecal cortisol concentrations in a northern population of snowshoe hares

    Montgomerie, Claire Kornet; Kielland, Knut; Breed, Greg; Lian, Marianne (2020-08)
    Blood biomarkers indicative of nutritional status, fecal cortisol metabolite concentrations and an established body condition index (BCI), were collectively examined from snowshoe hares(Lepus americanus) inhabiting northern Alaska in 2018, during five ecologically significant times of year. As a novel approach to increase our understanding of the effects of diet and predation pressure on hare physiology, I addressed how these markers were associated with seasonal timing of energetic demands and adult survival rates. Mean decreases in concentrations of total protein (TP), blood urea nitrogen (BUN), hematocrit (HCT) and glucose during spring and autumn, suggest that snowshoe hare nutritional status decreased during these two seasons in 2018. The shoulder seasons of spring and autumn coincide with energetic challenges, including molt, changes in diet and breeding. Because available forage during these seasons largely consists of winter-dormant twigs, the energy expenditure of growing a new winter coat (autumn) and breeding behavior (spring) may compromise the energy balance of hares during these periods. Male hares, whose activity levels increase during breeding, exhibited lower BCI scores and were slower to molt from white to brown than female hares in May. Furthermore, adult survival rates were lowest during spring months. Snowshoe hare mean fecal cortisol metabolite concentrations did not show associations with seasons of apparent low nutritional status. Adult hare survival rates peaked during summer and early autumn, during which mean values of TP, BUN, Hct, Cl (chloride), Na (sodium) and glucose also increased. By contrast, this period coincided with a 2-fold increase in mean fecal cortisol metabolite concentrations, suggesting that the apparent stressor was not related to nutrition. Interestingly, after having decreased in autumn, BUN, Hct, TP, and glucose mean concentrations increased in midwinter. Free calcium (iCa) and potassium (K) mean concentrations were also highest in December. Hares may have reduced activity during winter months, and metabolic rates may have increased to cope with thermoregulation demands. BCI scores decreased by December, suggesting use of endogenous reserves. Lowest seasonal mean cortisol metabolite concentrations were also observed in mid-winter. This study demonstrates the value of examining both physiological and morphological metrics of snowshoe hare condition to better our understanding of how seasonal trends in food and fear may unfold into cyclic patterns.
  • Landscape characteristics influence climate change effects on juvenile chinook and coho salmon rearing habitat in the Kenai River watershed

    Meyer, Benjamin; Rinella, Daniel; Wipfli, Mark; Schoen, Erik; Falke, Jeffrey (2020-08)
    Changes in temperature and precipitation as a result of ongoing climate warming in south-central Alaska are affecting juvenile salmon rearing habitat differently across watersheds. Work presented here simulates summer growth rates of juvenile Chinook and coho salmon in streams under future climate and feeding scenarios in the Kenai River (Alaska) watershed across a spectrum of landscape settings from lowland to glacially-influenced. I used field-derived data on water temperature, diet, and body size as inputs to bioenergetics models to simulate growth for the 2030-2039 and 2060-2069 time periods, comparing back to 2010-2019. My results suggest decreasing growth rates under most future scenarios; predicted changes were of lower magnitude in the cooler glacial watershed and main stem and more in montane and lowland watersheds. The results demonstrate how stream and landscape types differentially filter a climate signal to juvenile rearing salmon habitat and contribute to a broader portfolio of habitats in early life stages. Additionally, I examined two years of summer water temperature data from sites throughout our study tributaries to assess the degree to which lower-reach sites are representative of upstream thermal regimes. I found that the lower reaches in the lowland and glacial study watersheds were reasonably representative of daily and seasonal main stem thermal conditions upstream, while in the montane study watershed (elevation and gradient mid-way between the lowland watershed) upstream conditions were less consistent and thus less suitable for thermal characterization by a lower-reach site alone. Together, this work highlights examples of the importance of accounting for habitat diversity when assessing climate change impacts to salmon-bearing streams.
  • Abundance, composition and distribution of predatory gelatinous zooplankton in the northern Gulf of Alaska

    Mendoza Islas, Heidi M.; Hopcroft, Russell R.; Coyle, Kenneth O.; Cieciel, Kristin; Danielson, Seth (2020-08)
    Jellyfish are conspicuous yet under-studied components of marine zooplankton communities. Abundance, biomass, size, and distribution of large-jellyfish were measured during July and September of 2018 and 2019 as part of the Northern Gulf of Alaska Long-Term Ecological Research (NGA-LTER) cruises. Nearly 1000 kg dispersed among ~13,800 jellies were collected using a 5 m² Methot net. Catches were dominated by two macro-jellies, the hydrozoan Aequorea sp. and the scyphozoan Chrysaora sp. During 2018, epipelagic macro-jellies biomass averaged 1.46 ± 0.36 g WW m⁻³ for July and 1.14 ± 0.23 g WW m⁻³ for September, while during 2019 they averaged 0.86 ± 0.19 g WW m⁻³ for July and 0.72 ± 0.21 g WW m⁻³ by September. Despite similar biomass among sampling seasons within the same year, July abundances were fivefold greater than abundances in September, with July catches dominated by juvenile jellyfish over the inner shelf, while during September jellyfish adults were more prominent and most predominant at offshore stations. Comparison to over 20 years of data from standard towed nets allowed determination of the relative magnitude of the three dominant predatory zooplankton components: Scyphozoans, Hydrozoans, and Chaetognaths in the NGA. The biomass of these smaller epipelagic predators (10 mg WW m⁻³ for hydrozoans and 8 mg WW m⁻³ for chaetognaths) is a low percentage of the macro-jellies, despite their much higher numerical abundance. Acknowledging that changes in gelatinous biomass could have profound effects on fisheries, we argue that jellyfish should be quantitatively monitored in ecosystems with high fisheries productivity.
  • Analysis of the 2015 Sagavanirktok River flood: associated permafrost degradation using InSAR and change detection techniques

    McClernan, Mark Timothy; Meyer, Franz; Zwieback, Simon; Minter, Clifton (2020-08)
    In 2015, the Sagavanirktok River experienced a sequence of high, early-winter temperatures that lead to a buildup of aufeis. The buildup displaced the spring runoff causing widespread flooding. Flood waters inundated the surrounding tundra introducing heat into ground ice-baring soils. The Sagavanirktok River flood was caused by an extensive ice dam that developed the previous winter. The first flooding pulse started in April 2015, when an aufeis obstruction diverted river water to the surface. The obstruction caused flooding along 24 km of the Dalton Highway and its surroundings, necessitating a prolonged highway closure and emergency repairs. A second flooding pulse was caused by annual spring runoff in May 2015, which was driven by rapid snowmelt due to warm seasonal temperatures. The washed-out highway had to be closed again. Field investigations showed that thermal erosion of ice wedges in the tundra adjacent to the Dalton Highway caused local subsidence by several meters. However, the full environmental impact of the flood has not yet been quantified regionally or temporally. Thermokarst formation, can cause rapid ecological and environmental changes. Thawing of permafrost can lead to terrain instability as the melting of ground ice induces subsidence and loss of soil strength. The processes involved in permafrost degradation are complex, as is predicting terrain stability and the associated impacts to permafrost surrounding infrastructure. The immediate impact of the 2015 Sagavanirktok River flood is evident, which caused rapid terrain collapse in the vicinity of the Dalton Highway and the Trans-Alaska Pipeline near Deadhorse, North Slope Borough, Alaska. Thermal degradation of permafrost can be expressed as the change in the surfacemicrotopography over several years following a flood. Change detection, digital elevation model differencing, and InSAR were employed within the area of interest to understand the extent of the flood and deformation within inundated areas. To determine the likely impacted areas within the area of interest and expanse of the flood, an unsupervised change detection technique of high resolution TerraSAR-X and Sentinel-1 amplitude images was utilized. The topographic deformation analysis to determine the motion on the ground surface used a short baseline subset InSAR analysis of Sentinel-1 data during the summer season following the Sagavanirktok River flooding events. Additional deformation analysis was conducted with ALOS-2 data for annual comparison of the 2015 to 2019 summers. TanDEM-X digital elevation model differencing compared surface models generated from before and after the Sagavanirktok River flood. Elevation model differencing would identify the absolute change between the acquisition time of the surface models. A joint data analysis between deformation and differenced elevation models analyzed the contrast within inundated and flood-unaffected areas; thus, the changes and impact to the permafrost following the 2015 Sagavanirktok River flood. The Sagavanirktok River flood highlights the vulnerability of ice-rich permafrost to flooding. A change in the vicinity of the Sagavanirktok River Delta to the hydrological cycle led to widespread increases in terrain instability. Analysis of summer season deformation data suggested inundated permafrost areas showed lower seasonal deformation in years following the flood. Analysis of annual deformation shows permafrost subsidence intensified in inundated areas in the years following the flood. Digital elevation model differencing produced a statistically ambiguous result. This research illustrates the value of combining TerraSAR-X, TanDEM-X, Sentinel 1, and ALOS-2 microwave remote sensing missions for evaluating widespread surface changes in arctic environments. However, annual deformation data proved the most usable tool in observing the changing permafrost ecosystems around the Sagavanirktok River.
  • Assessing adverse effects of mercury in two pinniped species

    Lian, Marianne; O'Hara, Todd M.; Rea, Lorrie D.; Kuhn, Thomas B.; Van Wijngaarden, Edwin (2020-08)
    This dissertation studies measures of adverse effects in free-ranging pinnipeds associated with relatively high total mercury ([THg]) or monomethylmercury ([MeHg+]) concentrations, relatively low total selenium ([TSe]) concentrations and/or low TSe:THg molar ratios. Both the Steller sea lion (SSL, Eumetopias jubatus) and Pacific harbor seal (HS, Phoca vitulina richardii) inhabit coasts of the North Pacific, and are considered important sentinel species for One Health (environmental, animal and human health). Relatively high [THg] is reported for some animals in both species, causing concern for adverse effects especially in the developing fetus. Maternal piscivorous diet can expose the fetus to MeHg⁺ at a vulnerable developmental stage, with potential for adverse effects on several organ systems. This dissertation focused on two of these: nervous system development and function and oxidant/antioxidant homeostasis. In Chapter 2 I outlined capture and field anesthesia of free-ranging SSL. I found faster induction times for sevoflurane over isoflurane, with a significant interaction for anesthetist. Difference among the two agents is most likely attributed to the different chemical properties for these gases (blood solubility), whereas personal experience/comfort level most likely explains the differences between the human operators. Severe hypothermia was also documented, associated with the time of year, sex and duration of anesthetic event. There was an overall low mortality rate, and the protocols were effective for relatively safe field anesthesia of a large mammal. Chapter 3 assessed oxidant/antioxidant status and associations with [THg], [MeHg⁺], [TSe] and TSe:THg molar ratio in anesthetized free-ranging SSL pups. The anesthesia protocols described in Chapter 2 were used as a physiological stressor for measuring oxidative stress in SSL. Pinnipeds as diving mammals are naturally adapted with high antioxidant activity to survive long breath-holds during foraging. However, the relatively high [THg] found in some SSL cause concern for sequestration of Se due to its high binding affinity to Hg, and subsequently decreased antioxidant capacity (Se-dependent glutathione peroxidase (GPx)). I found a significant negative relationship between lipid peroxidation and [TSe], suggesting the potential for decreased antioxidant protection from Se. There were also significant associations between increased GPx activity and lipid peroxidation, possibly protecting pups with relatively high [THg] and low TSe:THg molar ratios. In Chapter 4 I repeatedly evaluated live-stranded HS pups admitted to The Marine Mammal Center, using weekly clinical and behavior assessments, which were analyzed for associations with [THg]. There was a significant association between [THg] in hair and/or blood and decreased response to tactile stimulation, less movement and longer stays in rehabilitation. These findings will help us better assess similar [THg] in hair and blood of SSL in Alaska that we currently study as well as other pinnipeds. In summary, this dissertation confirms the potential for adverse effects in two free-ranging species of pinnipeds exposed to MeHg⁺ in utero.
  • Stigma, self-efficacy, and adherence behaviors in people with type 2 diabetes: unexpected outcomes

    Laweryson, Annie N.; Campbell, Kendra; Dulin, Patrick; David, EJR; Rivkin, Inna (2020-08)
    Type 2 diabetes mellitus is a health condition treated with behavioral modifications including changes in diet, exercise, foot care regimens, and medication. Stigma associated with type 2 diabetes negatively effects health outcomes, whereas patient-provider relationships positively affects health outcomes. The growing literature base on type 2 diabetes stigma and health outcomes is mostly conducted outside of the United States. The present study used online crowdsourcing methods to gather cross-sectional survey data from people (n=152) who have been diagnosed with type 2 diabetes and are living in the United States. Participants completed the survey battery measuring stigma, self-efficacy, patientprovider relationships, and health behaviors. It was predicted that 1) internalized stigma would have a negative impact on self-care behaviors including diet, exercise, foot care, and medication adherence as well as glycated hemoglobin [HbA1C] levels 2) self-efficacy would mediate each of those relationships, and 3) the patient-provider relationship, characterized by trust in providers would moderate the relationship between stigma and self-efficacy thus indirectly moderating self-care behaviors and HbA1C. To test these hypotheses, a set of five moderated-mediation analysis were conducted to test each outcome variable of diet, exercise, foot care, medication adherence, and HbA1C. Main findings of this study revealed paradoxical relationships between stigma, self efficacy, and trust in providers, although consistent with psychological reactance theory. Stigma was associated with medication non-adherence and worse HbA1C, which is consistent with literature. Results of this study suggest that patients who exhibit psychological reactance may struggle to adhere to recommendations despite being more likely to report that everything is okay. This dynamic may make it difficult for providers to accurately gauge patient engagement in care, ability, or progress in health behavior change. However, one could argue responding to stigma with reactance may be protective in other ways. There was some evidence to suggest providers can attend to reactance by attuning to trust within the patient-provider relationship. In summary, this study adds to the pool of literature on stigma and type 2 diabetes, specifically within the US which is important considering variances in social climates and health care systems across nations. Future research should corroborate our suppositions about the relationships between stigma, self-efficacy, and psychological reactance.
  • Environmental impacts on reproductive responses of Pacific walruses (Odobenus rosmarus divergens) and subsistence users of St. Lawrence Island

    Larsen Tempel, Jenell T.; Atkinson, Shannon; Kruse, Gordon H.; Fugate, Corey; Pyenson, Nick (2020-08)
    An interdisciplinary approach is used in understanding change and resiliency in St. Lawrence Island (SLI) resources and resource users throughout this dissertation. Historically SLI inhabitants have relied on the Pacific walrus (Odobenus rosmarus divergens) for their survival and this resource is still highly valued for cultural and dietary purposes. The responses of Pacific walruses and SLI subsistence users to environmental change was analyzed. In walruses, reproductive capacity was analyzed using an anatomical approach as well as reproductive plasticity which was determined using a physiological approach to characterize their estrus cycle. A suite of anatomical measurements were developed to characterize reproductive capacity of walruses by analyzing ovaries from three distinct time frames during a 35-year period. Reproductive capacity was reduced during time frames when carrying capacity (K) was reached and when large environmental changes occurred in the Bering Sea, including years of very low sea ice extent. Reproductive capacity was high in times when K was lower and harvest levels were greater. Our results explained how perturbations in K and environmental changes may have influenced reproductive capacity of the population in the past. Endocrine techniques were used in ovarian tissues to determine if progesterone and total estrogens are useful indicators of female reproductive status in walruses harvested during the spring hunt. Progesterone and total estrogen concentrations were greater in the reproductive tissues of unbred and pregnant females than postpartum females, however neither hormone could distinguish between pregnant and unbred animals. These results provide the first physiological evidence for pseudopregnancy in this species, rather than a postpartum estrus. Lastly, discussions were held with SLI community members to determine changes in key subsistence resources and community resiliency with regard to food security. Walruses ranked highest among key resources. Stakeholders reported limited access and increased effort to hunt walruses, changes in crab abundance, and increases in commercially exploitable fish stocks. Changes were attributed to loss of sea ice, "bad" weather, and climate change. In order for SLI communities to continue their subsistence-based way of life, inhabitants may need to expand their diet to include less-preferred food items in place of harvested ice-associated species. In conclusion, loss of sea ice and rapid environmental changes in the Bering Sea have the potential to greatly impact walrus reproduction and the marine subsistence way of life that is practiced by SLI stakeholders.
  • Developing a Data-Driven Safety Assessment Framework for RITI Communities in Washington State

    Wang, Yinhai; Sun, Wei; Ricord, Sam; de Souza, Cesar Maia; Yin, Shuyi; Tsai, Meng-Ju (2021-09-10)
    The roadway safety of the Rural, Isolated, Tribal, or Indigenous (RITI) communities has become an important social issue in the United States. Official data from the Federal Highway Administration (FHWA) shows that, in 2012, 54 percent of all fatalities occurred on rural roads while only 19 percent of the US population lived in rural communities. Under the serious circumstances, this research aims to help the RITI communities to improve their roadway safety through the development of a roadway safety management system. Generally, a roadway safety management system includes two critical components, the baseline data platform and safety assessment framework. In our Year 1 and Year 2 CSET projects, a baseline data platform was developed by integrating the safety related data collected from the RITI communities in Washington State. This platform is capable of visualizing the accident records on the map. The Year 3 project further developed the safety data platform by developing crash data analysis and visualization functions. In addition, various roadway safety assessment methods had been developed to provide safety performance estimation, including historical accident data averages, predictions based on statistical and machine learning (ML) models, etc. Beside roadway safety assessment methods, this project investigated the safety countermeasures selection and recommendation methods for RITI communities. Specifically, the research team has reached out to RITI communities and established a formal research partnership with the Yakama Nation. The research team has conducted research on safety countermeasures analysis and recommendation for RITI communities.
  • Development of scalable energy distribution models to evaluate the impacts of renewable energy on food, energy, and water system infrastructures in remote Arctic microgrids of Alaska

    Karenzi, Justus; Wies, Richard; Huang, Daisy; Al-Badri, Maher (2020-08)
    Experience and observations from remote Alaska communities have shown that energy is inarguably at the center of food, energy, and water (FEW) security. The availability of potable water, fresh produce, food storage, or processed seafood ultimately depends on a reliable and adequate energy supply. For most communities, diesel fuel is the primary source of power, which comes at high cost because of the logistics associated with importing the fuel to these relatively isolated communities. Integrating locally available renewable energy resources not only enhances energy supply, but the impacts further translate to food and water security in remote microgrids. The focus of this work is to investigate how intermittent renewable energy sources impact community level food and water infrastructure systems in a remote Arctic microgrid. Energy distribution models are mathematically developed in MATLAB® Simulink® to identify, describe, and evaluate the connections between intermittent renewable resources and the FEW loads. Energy requirements of public water systems, greenhouses, cold storage units, seafood processing loads, and modular water and food system loads are evaluated. Then energy sources including solar PV, solar thermal collectors, wind, hydro, energy storage, and diesel electric generation are modeled and validated. Finally, simulations of scenarios using distributed energy resources to serve water and food infrastructure loads are carried out including the incorporation of dispatchable loads. The results indicate that the impacts of renewable energy on FEW infrastructure systems are highly seasonal, primarily because of the variability of renewable resources. The outcome of this work helps in gaining firsthand insights into FEW system dynamics in a remote islanded microgrid setting.

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