• 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.
    • Liberal deradicalization in the adaptation of novels to film: defining antiheroes, from Heathcliff to Walter White

      Kraft, Benjamin; Carr, Richard; Hirsch, Alexander; Harney, Eileen (2021-08)
      Using research from the history of the Victorian novel and recent media, I demonstrate the value in re-examining the critical importance of the antihero. Using a methodology of combining neo-Marxian analysis, adaptation studies, and a re-thinking of what constitutes novels and television serials, I explore how antiheroes are defined and why those definitions are often not inclusive to controversial, but seemingly definitional antihero examples. As informed by a critique of how antiheroes are defined, I use my research to discuss the underlying characteristics of the antihero across genres. From a perspective of critiquing liberalism adopted from Emily Brontë's Wuthering Heights and Vince Gilligan's Breaking Bad, I structure textual evidence in support of antiheroes being identified according to three traits: sympathy, violence, and radical speech. The literary and real-world impact of each trait is argued according to evidence qualified by a neo-Marxian methodology, using an original synthesis of Louis Althusser's aleatory politics and the Marxist cultural critiques of Raymond Williams. Finally, these three traits are strongly evinced in the real-world systemic critiques of liberalism represented in both Heathcliff and Walter White.
    • 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.
    • Mental health problems in the mountains: needs, assets, and recommendations for managing mental health problems in mountain-focused wilderness-based education and related fields

      Johnson, Samuel H.; Dulin, Patrick L.; Lopez, Ellen D. S.; Gifford, Valerie M.; Rivkin, Inna D. (2020-08)
      Background: Through controlled exposure to stress, wilderness-based education programs can buildcapacity for adaptive coping and produce long lasting improvements to participants' quality of life.However, stress can also overwhelm them, resulting in the emergence and exacerbation of mental health vulnerabilities in the field. However, empirically grounded best practices for training, pre-trip screening, and protocol/policy for mental health specific to the wilderness context are not well developed. Aim: The aim of this study was to assess needs and assets, and develop recommendations for training, pre-trip screening, and organizational protocol/policy to assist with successful management of mental health problems in mountain-focused, wilderness-based education and related fields such as outdoor leadership, guiding, environmental education, snow safety, search and rescue, and wilderness therapy. Methods:A pragmatic, two phase, sequential mixed methods approach was utilized to explore this topic within the context of an overarching collaborative community based participatory research (CBPR) framework with organizational partners: National Outdoor Leadership School, Outward Bound USA and Canada, the Wilderness Risk Management Conference, and the Alaska Mountaineering School. A preliminary quantitative study utilized a cloud-based survey to determine baseline characteristics for 64 wilderness-based educators, guides, outdoor leaders, snow safety professionals, and search and rescue personnel. Qualitative interviews with 16 experienced and prepared key informants addressed the study aim in more depth, consistent with partnering organization priorities, in the tradition of CBPR. Findings: Mental health topics and skills are underemphasized in current training, and training was found to be of less value than personal and professional experiences with mental health. In the future, mental health should be increased and emphasized, possibly through the utilization of existing resources such as the stress continuum or curriculum such as Psychological First Aid as well as practical training opportunities that emphasize experiential learning around mental health. Current screening can present both risks and benefits for clients, instructors, and organizations. Nondisclosure and the impacts of stigma and prejudice on the interpretation and utilization of mental health screening information were major concerns. However, screening can guide preventive and proactive efforts, and build working relationships with potential participants. Future screening should be used to inform participants about course stress, encourage disclosure, and direct curriculum development. Multi-step screening, utilizing multiple interactions with participants before the course, was identified as a utilitarian way to facilitate improvements for future screening. In protocol/policy, field management of mental health problems is underemphasized relative to evacuation, resulting in overutilization of disruptive evacuation processes. While many organizations do well at responding to instructor mental health needs after incidents such as a fatality in the line of work, inconsistencies in implementation can create unintended barriers to instructor self-care. Future protocol/policy should prioritize instructor mental health by addressing inconsistencies in implementation, removing barriers to self-care and guiding the deployment of resources such as responsive staffing or free counseling benefits. Implications: This study contributes uniquely to the literature by providing an empirically-based perspective into a little researched topic, and multiple avenues for implementation of findings such as increasing mental health content and experience-based training, utilization of multi-step screening processes, and consistent implementation of organizational protocol/policy in support of client and instructor mental health. Recommendations for implementation address weaknesses and build upon strengths already present in training, screening, and protocol/policy. Overall, practice and research in this area are in need of further investigation and development. Future dissemination, research, and practice development could help develop measures or resources to support the improvement of training, screening, and protocol/policy across wilderness-based education and related fields.
    • Metabolite influence on the hibernating Arctic ground squirrel

      Rice, Sarah A.; Drew, Kelly; Kuhn, Thomas; Coker, Robert; Ritter, Robert (2020-12)
      Hibernation is a state of extreme metabolic plasticity and fasting. How hibernators maintain nitrogen homeostasis and regulate amino acid metabolism and how those metabolites influence hibernation physiology remains unknown. We first utilized three approaches to understand nitrogen homeostasis and amino acid metabolism in hibernation: longitudinal metabolic profiling within individual animals over undisturbed torpor, in vivo amino acid isotope tracing in deep torpor, and ¹⁵N isotope tracing in vivo during arousal from hibernation in Arctic Ground Squirrels (AGS). We observed that in vivo whole body production (WBP) of metabolites in deep torpor are profoundly and selectively suppressed in deep torpor. Metabolic profiling over undisturbed torpor bouts shows amino acids with nitrogenous side chains accumulate over torpor while urea cycle intermediates remain unchanged. During arousal from hibernation, ¹⁵N isotope tracing demonstrates recycling of free nitrogen into non-essential amino acids, essential amino acids and the gamma-glutamyl system. We next utilized two approaches to understand potential metabolite influences on thermogenesis and behavior in hibernation: we infused ammonium acetate in deep torpor and fed diets high in omega 3 fatty acids and monitored body temperature and torpor bout length. We found high doses of a nitrogen donor, ammonium acetate, as well as diets high in omega 3 fatty acids both influence thermogenesis in hibernation. In conclusion, production of metabolites in deep torpor indicate highly regulated metabolism with accumulation of nitrogen carrying amino acids. We additionally show metabolites and nitrogen can exert thermogenic influence on hibernating AGS.
    • Meteorological drivers of lightning in Alaska on seasonal and sub-seasonal timescales

      Chriest, Jonathan; Bhatt, Uma S.; Bieniek, Peter A.; Walsh, John E. (2021-05)
      Wildfire has long been a part of the Boreal forest ecosystem in Alaska and the increasing number of large fire seasons over the past 2 decades has had substantial economic and health impacts. Boreal wildfires are expected to continue to increase over the next century in part due to a projected increase in lightning. This motivates developing lightning outlooks to inform fire management decisions regarding the economic allocation of shared firefighting resources including but not limited to personnel and air tankers. The goal of this research is to identify key meteorological parameters associated with lightning processes on a stroke-by-stroke spatial scale and at hourly-to-sub-seasonal timescales. This is a first step towards developing robust lightning outlooks. In order to identify the key parameters, lightning data for the Alaska Lightning Detection Network was paired with hourly European Center Reanalysis Version 5 (ERA5) over the 2012-2019 study period. This data was analyzed on the scale of Alaska Fire Service Predictive Service Areas (PSAs) and three sub-seasons of the Alaska fire season. This strategy helped to identify regional and sub-seasonal variability and made the research operationally relevant. Key results from this research include the following. The majority of lightning occurs in the duff driven sub-season across all PSAs. Lightning, particularly in the Interior PSAs, follows a diurnal pattern with lightning on average beginning earlier in the day in the eastern portion of Alaska and later in the day in the western portion of Alaska. This distinctive pattern is not as well defined in the Coastal PSAs. Results also suggested that dry lightning may be more prevalent in portions of the western Interior than in other regions of Alaska. Lightning events were more common under specific atmospheric flow directions at 500 and 700 hPa, where these directions varied by PSA. Northeasterly and northwesterly flow aloft were most favorable for lightning in the Tanana Valley West PSA, while southerly flow aloft was more favorable for lightning in the North Slope and Upper Yukon PSAs. Finally, easterly flow was a more common pattern during lightning strokes in the Seward Peninsula and Kuskokwim Valley PSAs.
    • The mineralogical associations, distribution, and mineral zoning of cobalt in the Bornite deposit, southwest Brooks Range, AK

      Mahaffey, Zachary B.; Newberry, Rainer; Schrader, Christian; Regan, Sean (2021-08)
      The Bornite Cu-Co deposit is predominately hosted in dolomitic marble with interstratified phyllite; the mineral resource is restricted to the Upper, Lower and South Reefs. Cobalt is primarily from carrollite (ideally CuCo₂S₄), cobaltite (ideally CoAsS), and cobaltiferous pyrite ((Fe,Co)S₂). The Co minerals can contain significant Ni, and the Ni rich endmembers, millerite (NiS) and gersdroffite (ideally NiAsS), also rarely occur. Detailed handheld XRF analyses on 15 drill holes, coupled with reflected light petrography, electron microprobe-based compositional maps, and electron microprobe analyses (EPMA) have shown complex compositions, textures, associations, and spatial distribution of the Co minerals in the Bornite deposit. Carrollite compositions and textures vary with the Cu-sulfide assemblage: carrollite with bornite is commonly porphyroblastic and approximated by Cu(Co,Ni)₂S₄, whereas carrollite lacking associated bornite is interstitial and represented by (Cu,Ni)(Co,Ni)₂S₄. Cobaltite occurs in two generations: early As-depleted, Ni-poor, and metastable ((Co,Fe)As₀.₅S₁.₅ to (Co,Fe,Ni₀.₀₆)As₀.₈₈S₁.₁₂), and late near stoichiometric ((Co,Fe,Ni₀.₀₁)As₀.₉S₁.₁ to (Co,Fe,Ni₀.₉₄)As₁S₁). The latter rims and (or) replaces the former. The virtual lack of cobaltite in assemblages containing bornite + pyrite, along with carrollite compositions, suggest a gradient in Cu and Co activity that increased with increasing fS₂. Distinct carrollite zones associated with higher Cu grades are present in the high-grade zone (Number One Orebody) of the Upper Reef and the South Reef. Decreasingly Cu-rich assemblages dominated by chalcopyrite + pyrite and cobaltite are outside the carrollite zones. The Lower Reef has lower Cu grades, lacks a carrollite zone, and variably contains cobaltite. Due to these different Co mineral distributions, the Bornite deposit cannot represent dismemberment of a single homogeneous body. Bornite pyrite can contain Ni and Cu (both inversely correlated to Co) and As (maximum 5.6%, generally correlates with Co). Compositions of Co-pyrite lacking significant As (up to 8.5% Co) and late cobaltite suggest temperatures of 400-500℃, consistent with Upper Blueschist to Greenschist conditions. Pyrite compositions can be extremely variable within a single sample and even within a single grain: nearly half of all EPMA pyrite analyses yield < 0.25% Co. Clearly metamorphic (porphyroblastic) pyrite displays concentric oscillatory Co + As zonation. Average Co content in pyrite generally increases with Cu grade, which suggests Devonian Co and Cu deposition occurred simultaneously. Co deportment is a function of location in the deposit, which correlates with Cu grade and Co mineral zonation. Based on metal balance calculations, more than half (on average 57%) of the Co in South Reef intervals with > 0.5% Cu is due to Co-pyrite. In the Lower Reef the proportion is much higher: 55-93%. High Cu grade intervals typically yield increased carrollite abundance and decreased cobaltite. Carrollite consistently reports to the Cu concentrate, however, cobaltite recovery is variable and can report to the tails with Co-pyrite. Thus, maximizing Co recovery from Bornite will require producing a pyrite concentrate in addition to the Cu concentrate.
    • Modeling permafrost dynamics and water balance of Arctic watersheds in a changing climate

      Debolskiy, Matvey Vladimirovich; Hock, Regine; Romanovsky, Vladimir E.; Alexeev, Vladimir A.; Nicolsky, Dmitry J. (2020-12)
      Changes in climate across the Arctic in recent decades and especially the increase of near-surface air temperature promote signicant changes in key natural components of the Arctic including permafrost (defined as soil experiencing subzero temperature for more than two consecutive years). Recent borehole observations exhibit signicant increase in ground temperatures below the depths of seasonal variations. Modeling studies on a global scale suggest a steady decrease in area underlain by near-surface permafrost in the northern hemisphere in recent decades. Global projections for the next century predict further permafrost degradation depending on the greenhouse gas concentration trajectory. Permafrost degradation is not only associated with climate feedbacks but can also result in signicant changes in coastal and terrestrial ecosystems and increased risks of costly infrastructural damage for Arctic settlements. In addition, permafrost plays an important role in the terrestrial part of the Arctic freshwater cycle as the volumes of frozen ground are practically impermeable for subsurface moisture transport and contain excess water in the form of ground ice. Since geophysical observations bear signicant costs in the Arctic, especially in the remote areas, simulations performed with physically based numerical models allow researchers to assess the current state of permafrost in Arctic regions and make future projections of its dynamics and resulting hydrological impacts. In this dissertation we use numerical modeling in two distinct ways: 1) to estimate current and future ground temperature distribution with high resolution on a regional scale and 2) to evaluate the role permafrost degradation plays in changes in water balance of watersheds under changing climate. First, we study the permafrost evolution of the Seward Peninsula, Alaska over the 20th and 21st century using a distributed heat transfer model. Model parameters are calibrated with a variational data assimilation and are distributed across the study domain with an ecosystem type approach. Simulations suggest that the peninsula will experience a reduction in the near surface permafrost extent of up to 90% and an average increase in ground temperature across the peninsula up to 4.4°C towards the end of the 21st century under the high greenhouse gas concentration trajectory. Second, we perform an ensemble of millennia-long experiments by simulating hypothetical idealized small-scale watersheds placed in a typical Sub-Arctic setting with a physically based distributed hydrological model. In these experiments we single out the effects of temperature dependent subsurface moisture transport by applying air temperature change in our forcing scenarios only to sub-zero temperatures within a given year. Results suggest a long-term increase in annual runoff of 7-15% and a similar decrease in evapotranspiration under a prolonged (up to a millennia) air-temperature increase. The short-term (< 100 years) water balance response highly depends on soil permeability and the watersheds slope and profile curvature. The simulated changes in water balance are a direct result of the decrease in near- surface soil moisture and intensified subsurface moisture transport in the deeper soil layers due to the permafrost thaw. Additional experiments suggest that simplied models that do not include lateral subsurface moisture transport, as typically done in Earth System Models, can reproduce similar changes in equilibrium water balance to the ones predicted by more sophisticated models for the watersheds with gentle slopes. We also find that if the air temperature trend is reversed and watersheds are experiencing prolonged cooling, a high degree of hysteresis in water balance behavior can be observed, however, the long-term changes in water balance are equal in their amplitude. Additionally, we find that initial soil moisture distribution in the deeper soil which is essentially a consequence of the paleoclimate (given the same permeability and topography) determines the overall soil moisture storage deciency which in turn results in the lag between the onset of warming and the increase in total runoff. The deficit in soil moisture storage is highly dependent on the watersheds topography.
    • Modeling supraglacial lake drainage and its effects on the seasonal evolution of the subglacial drainage system in a tributary glacier setting

      Franco, Nevil Arley; Truffer, Martin; Wackerbauer, Renate; Delamere, Peter (2021-08)
      This work aims to gain a better understanding of the relationship between glacier motion and water distributed through subglacial drainage systems. A numerical scheme (GlaDS) is used to model both inefficient and efficient drainage systems to see which dominates after the draining of a supraglacial lake on a synthetic glacier that is made up of an outline that features a main branch and a tributary. The geometry is based on the surgetype Black Rapids Glacier (Ahtna Athabascan name: Da lu'itsaa'den) in Alaska, where a lake develops in the higher ablation zone, and drains rapidly early in the melt season. It has also been observed that this lake drainage causes a twofold or threefold speed-up of the main branch, with some acceleration of the lower-lying Loket tributary. This speed-up can be considered a surrogate for a surge, which also initiates in the main branch, while, during times of quiescence, the ice flow on the tributary is dominant. We investigate the effects of varying timing and volume inputs of lake drainage with a focus on its effects beneath the tributary. We find that the response of the glacier depends on the seasonal timing, the amount of water from the draining lake, and its location on or near the margins of the glacier. Results show that an inefficient drainage system is the cause of the glacier speed-up, both when the lake drains rapidly or when there is an extended time in drainage, at any time of the season. The speed signals vary throughout the glacier depending on the location of the lake relative to that of an evolved efficient drainage system.
    • Neuroendocrine and glial cell remodeling in a hibernating mammal

      Duncan, Cassandra; Williams, Cory; O'Brien, Kristin; Christian, Helen (2021-08)
      In most seasonally breeding vertebrates, changes in photoperiod trigger the remodeling of neuroendocrine and glial cells known to be involved in activation of the reproductive axis. We used electron microscopy to determine whether similar remodeling occurs under conditions of continuous darkness during hibernation in arctic ground squirrels (Urocitellus parryii). Immediately prior to the reproductive season, arctic ground squirrels naturally sequester themselves in a persistently dark hibernacula for 6-8 months where they experience only muted fluctuations in ambient temperature. Hibernation consists of two to three week-long bouts of torpor, during which body temperature and metabolism are depressed, periodically interrupted by short (<24h) interbout arousals where animals become euthermic and metabolism returns to "normal" levels. Although their exact functions are unknown, interbout arousals are generally thought to be associated with homeostatic processes. With the exception of brief dynamic changes during interbout arousals, brain activity and neuroendocrine pathways are generally thought to be relatively static across hibernation. We hypothesized that interbout arousals may allow for cellular ultrastructural remodeling of pars tuberalis thyrotroph cells, hypothalamic tanycytes, and pars distalis gonadotroph cells across hibernation, allowing for animals to activate their reproductive axis in anticipation of the active season. To test this, we sampled brains from arctic ground squirrels during early, mid-, and late hibernation, as well as post hibernation. We found evidence for cellular remodeling and activation of the reproductive axis across hibernation including decreases in neuronal contacts with the hypothalamic basal lamina, increases in the cell area and decreases in granule density of pars distalis gonadotrophs, increases in gonadal mass, and upregulation of steroidogenic genes in gonadal tissue. We hypothesize that the return to euthermy during interbout arousals allows for remodeling of the hypothalamus and pituitary, which we tested by exposing male arctic ground squirrels to a warm ambient temperature (30°C) during midhibernation, which causes animals to prematurely end hibernation. However, the premature termination of hibernation resulted in limited ultrastructural changes, suggesting that temperature alone is insufficient to activate reproductive maturation. Altogether, our study reveals a previously underappreciated physiological dynamism during hibernation that allows animals to rapidly transition between seemingly incongruous life-history states.
    • A nonlethal, whole oocyte approach to determining spawn readiness in Pacific sand lance, Ammodytes personatus, in Southeastern Alaska

      Neff, A. Darcie; Norcross, Brenda L.; López, J. Andrés (2021-08)
      Knowing when a fish spawns is fundamental to understanding and sustainably managing it. The annual reproductive cycle of the iteroparous, total-spawning sand lances and sandeels (Ammodytidae) has been described almost exclusively using gonadal macroscopy and gonadosomatic indices (GSI), with little attention to gamete changes indicative of imminent ovulation and spawning. The latter was the focus of this study, in which spawn readiness of a southeastern Alaska population of Pacific sand lance (Ammodytes personatus) with unknown spawning phenology was assessed using light microscopy of whole oocytes. Oocytes were cannulated from spawning-capable females age-3 to age-9, measured for diameter, and classified into five developmental stages based on the coalescence of lipids and the position and integrity of the germinal vesicle. Oocyte maturation lasted 5-6 weeks, as determined by weekly cannulation of captive females. Diameter and developmental stage of oocytes were more precise metrics of readiness to spawn than macroscopy or GSI and indicated spawning in early- to mid-December. The examination of nonlethally collected whole oocytes is a quick, easy, and low-cost approach to the accurate and reliable assessment of spawn readiness in Pacific sand lance and offers the potential of success with congenerics and other total-spawning fish species.
    • Ocean and stream ecology of adult hatchery and wild pink salmon

      McMahon, Julia; Westley, Peter; Gorman, Kristen; McPhee, Megan; Rand, Peter (2021-08)
      In this thesis I investigate potential interactions of hatchery and wild pink salmon (Oncorhynchus gorbuscha) at sea and on the spawning grounds, in the context of the ecological and economic importance of modern Alaskan hatcheries. Although hatchery and wild salmon are known to interact, the nature and outcome of those interactions remain unclear. Here, I identify potential mechanisms of competition and hatchery salmon fitness with two datasets from Prince William Sound, Alaska, home to the largest pink salmon hatchery program in the world. First, I compared fitness-related traits such as body length, return timing, instream lifespan, and egg retention between straying hatchery and homing wild pink salmon to identify potential barriers or bridges to gene flow with over 120,000 individuals sampled over six years (2013-2018). Predicted lengths of hatchery and wild fish depended on the even or odd year lineage, return timing, and sex. Odd year pink salmon were smaller on average than even year pink salmon, odd year hatchery fish were smaller than wild fish, odd year length decreased over the season, and odd year males tended to be larger than females. In even years, hatchery pink salmon were larger on average than wild pink salmon, length increased over the season, and hatchery females were larger on average than any other group. I found no statistically significant differences in instream lifespan (2017: t-test (₂₀.₅₄), P = 0.41; 2018: t-test(₆.₂₆), P = 0.556) or egg retention (x²₍₂₎= 4.5, p = 0.11; 2017 and 2018 combined) between hatchery and wild fish. In contrast, I detected significant differences in stream life of the wild fish between two different sized streams in a manner consistent with observed black bear (Ursus americanus) predation; specifically stream life was shorter in the smaller stream with markedly higher predation. Second, I used stable carbon and nitrogen isotope analysis to test the hypothesis that hatchery and wild pink salmon have distinct foraging niches during their last months at sea, which could underpin observed differences in length between hatchery and wild pink salmon. Using data from 2015, I fit linear models and detected no difference in broad-scale foraging locations (delta¹³C values) of hatchery and wild pink salmon. However, trophic positions (delta¹⁵N values) for hatchery and wild pink salmon were inversely related to size where large wild salmon and small hatchery salmon tended to have the highest delta¹⁵N values. Because delta¹³C values and delta¹⁵N values of wild fish were positively associated with body size, it is likely that hatchery and wild pink salmon have size-dependent, yet still overlapping foraging niches. Overall, these results are consistent with the potential for hatchery and wild pink salmon to compete for resources on the spawning grounds and at sea to the extent that resources are limiting.
    • On estimating rotor noise generated by small unmanned multirotors

      Holst, Brian; Peterson, Rorik; Chen, Cheng-fu; Hatfield, Michael (2021-08)
      Unmanned aerial vehicles are utilized for missions ranging from wildlife surveillance to delivery of commercial goods. Previous research at the Alaska Center for Unmanned Aircraft Systems Integration (ACUASI) at the University of Alaska Fairbanks has focused on the monitoring of different species of wildlife, and some of this research was conducted utilizing multirotors. This work presents an introductory investigation and analysis of the acoustic noise generated by a single 15-inch rotor and applies this noise model to multiple rotors on a multirotor. The rotor is analyzed utilizing semi-empirical calculations and this work presents the process to continue acoustic analysis through simulation and analytical computation. Although this work studies, specifically, the 1555MR propeller designed by Advanced Precision Composites Propellers, the semi-empirical equations can be applied to other rotor designs. By investigating the analytical process, this work also presents a potential route through theory to identify the sound produced by these multirotors. The flow solution requires computational fluid dynamics software to output the flow on and around the rotors; this output can then be used for the analysis of noise. The total noise generated in stable hover is considered with certain assumptions about the blade geometry and aircraft motion. This work is organized into four chapters that detail the background, motivation, theory, setup, methods, results and conclusion. By utilizing this work and the works cited, readers and the researchers at ACUASI should understand the theory and be able to reproduce the results herein. With the estimation of noise of these multirotors, ACUASI will be able to refine their wildlife monitoring missions to ensure the observed animals are less affected by the noise generated by these vehicles.
    • Paleocene depositional history of the Cretaceous-Paleogene impact basin, Yucatan Peninsula, Mexico

      O'Malley, Katherine E.; Whalen, Michael; Fowell, Sarah; McCarthy, Paul (2020-12)
      In the spring of 2016, the International Ocean Discovery Program set out on Expedition 364 to recover core from the peak ring of Chicxulub Impact Crater at Site M0077. In total, 829 m of core was collected spanning granite to Paleogene sedimentary rocks. From this core, we have a well-preserved record of the Paleocene, which represents ~10 million years post impact in just under 10 m of sedimentary rock record. This has presented an incredible research opportunity, as we have gained invaluable information on how the environment responded and recovered from the global catastrophe that was the Chicxulub Impact. The Paleocene at M0077 is highly condensed and comprised of predominantly pelagic carbonate rocks. High resolution core logging and thin section analysis were used to identify facies in the Paleocene. Facies include marlstone, argillaceous wackestone, foraminiferal wackestone, and rare coarser grained lithologies such as packstone and grainstone. Overall, the Paleocene exhibits a succession of rhythmically bedded cycles composed of marlstones grading to argillaceous wackestones and capped by foraminiferal wackestones. Coarser grained lithologies only exist in the lower and uppermost portion of the core. In total, 72 cycles that ranged from 5-30 cm thick are identified and grouped into six larger packages based on pattern similarities in color, lithology, ichnofabric indices, and geochemical data. These cycles are interpreted as parasequences, and show predictable stacking patterns that allow us to make sequence stratigraphic analyses. Each package represents one to two systems tracts, and some can be correlated to eustatic sea level change. Recorded in this core is the progression of an initial sea level lowstand immediately post impact, and the fluctuation between highstands, lowstands, and transgressive systems tracts that follow. Major and trace elements were analyzed throughout the core, as well as delta¹³Corg and delta¹⁵Nbulk values. Three sets of geochemical proxies (paleoredox, detrital input, productivity) were used to provide insight into paleoecological conditions. Initial conditions in the crater show a period of high productivity, which tapers off within a million years post impact. Redox conditions vary, and show one major anoxic event, with other enrichments likely representing periods of pore water euxinia or increases in stratification leading to a more robust redox gradient.
    • Photosensitized degradation of chlorothalonil and chlorpyrifos in the presence of Arctic derived dissolved organic matter

      Quesada, Ginna; Guerard, Jennifer; Rasley, Brian; Green, Thomas (2021-05)
      Pesticides used at mid latitudes can accumulate in Arctic environments. Two commonly detected pesticides in Arctic lakes are chlorothalonil and chlorpyrifos. In surface waters, photolysis can play an important role in the attenuation of contaminants. The chemical characteristics of dissolved organic matter (DOM) can further alter the extent of photolytic degradation of pollutants. To determine the relative effect of natural Arctic lake water and its DOM on the photolysis of chlorpyrifos, experiments were conducted under natural Arctic irradiation and under artificial irradiation. Similarly, the effect of Arctic DOM was investigated for chlorothalonil under artificial irradiation. The fulvic acid (FA) fraction of DOM was isolated from Fog 1 and from Toolik Lake in May and July. Lake waters significantly enhanced the photodegradation of chlorpyrifos under natural light by up to an order of magnitude. FA's significantly increased the degradation of chlorpyrifos (>2x) and chlorothalonil (>100x) under artificial irradiation relative to 18 MΩ-cm Water. Toolik Lake FA isolated in May, significantly enhanced the photolysis of both contaminants relative to the isolate collected in July. In the presence of iron, a lower ratio of carbohydrates and peptides to aromatics in the FA's was associated with faster degradation for chlorothalonil.
    • Plasma transport and magnetic flux circulation in Saturn's magnetosphere

      Neupane, Bishwa Raj; Delamere, Peter; Ng, Chung-Sang; Newman, David; Wackerbauer, Renate (2021-08)
      The magnetospheres of outer planets are very different than the terrestrial magnetosphere. The magnetosphere of Saturn is rapidly rotating, and has its own plasma source. Enceladus located around 4Rs is the main source of plasma. The strong magnetic field of Saturn's magnetosphere picks up the plasma which experiences a strong centrifugal force in the non-inertial reference frame. The plasma produced in the inner magnetosphere has to be transported radially outward and lost to the solar wind. The transport of plasma in Saturn's magnetosphere is not fully understood. It is believed that transport is centrifugally-driven, occurring via flux tube interchange motions in the inner magnetosphere and via plasmoid expulsion in the magnetotail due to reconnection. It has been found that these mechanisms are not sufficient to explain the transport. We tried to determine different possible transport mechanisms that could exist in the outer planetary magnetosphere. Ma et al. (2019a) showed the low-specific entropy plasma with a narrow distribution in Saturn's inner magnetosphere and suggests a significant nonadiabatic cooling process during the inward motion while high specific entropy suggests the nonadiabatic heating during the outward transport. We have estimated the outward plasma transport rate about 55 kg s⁻¹. The calculation of magnetic flux transport and analysis of magnetic field data indicates that plasma transport in the Saturn magnetosphere could be dominated by small scale magnetic reconnection.
    • The politics of penguin pleasure: why animal sexualities matter to humans

      Emanuel, Nicole; Schell, Jennifer; Heyne, Eric (2021-08)
      This thesis is about what it means to think with penguins. It explores the ways in which we form ideas about these animals, and how those ideas can impact our beliefs about our own lives, penguins' lives, and the kinds of relationships that exist among humans and non-humans. It includes a survey of penguin representations across media and culture, particularly focusing on children's television and movies, nature documentaries, and non-fiction accounts of polar travel. While these penguin-centric texts can vary strikingly in tone, the penguins themselves appear again and again in an appealing light. Across a wide range of time and media, penguins are frequently portrayed as spunky, determined, and battling incredible odds to survive. That popular image of the plucky penguin has lent itself surprisingly well to debates about the naturalness of same-sex parenting in human society. The film The March of the Penguins (which was embraced by conservative Christians for its depiction of "traditional family values") and the picture book And Tango Makes Three (about two male chinstrap penguins who managed to successfully hatch an egg together at the Central Park Zoo) illustrate two sides of these public conversations. As the close reading and theoretical analysis performed in this thesis indicate, both views fail to truly understand penguins as living, courting, mating, reproducing beings. The behaviors of these actual animals are far too complex and varied to reduce to an alignment with either side of this fight over human concepts and morals.
    • Presentation of immunodominant peptides is strongly dependent on cathepsin resistance and preliminary cleavage of antigens

      Becker, Tynan; Ferrante, Andrea; Kuhn, Thomas B.; Chen, Jack; Leigh, Mary Beth (2021-08)
      An understanding of the basis for immunogenicity (the ability of a foreign substance to induce an adaptive immune response) is critical for advancing our knowledge of infectious or autoimmune diseases, as well as contributing to the design of vaccines and biologics. A key step in the initiation of an adaptive immune response is the presentation of pathogen-derived peptides by major histocompatibility class II (MHCII) molecules on the surface of antigen-presenting cells (APC) such as a dendritic cell (DC) to CD4⁺ T cells. Peptides that are superior at eliciting strong T-cell responses are termed immunodominant. The generation and selection of peptides occurs within a system of endosomal compartments that form when a DC takes up the antigen. These compartments become increasingly more acidic and reducing as proteolytic enzymes, MHCII and a peptide binding modulator human leukocyte antigen DM (HLA-DM, DM) are trafficked through to facilitate the degradation of proteins and the loading of peptides onto the MHCII. Although the general aspects of the antigen processing and presentation mechanisms are understood, important details of the endosomal machinery have yet to be determined. These studies focus on the elucidation of the pathways of antigen processing, the contribution of proteolytic cleavage to immunodominance, and the activity of four proteases in the cysteine family of cathepsins. Our findings strongly implied the existence of multiple, parallel pathways within antigen processing. These include the ability of MHCII to capture the native form of hemagglutinin (HA) from influenza A/New Caledonia 20/99 (H1N1), our model antigen, and the production of unique peptidomes through cleavage alone or through cleavage and capture by MHCII, in the presence or absence of DM, at varying pH. I demonstrate that one determinant for immunodominance is peptide resistance to cleavage by cathepsins, although it does not hold true for every immunodominant peptide. I establish that the cleavage of a protein and the generation of peptides available for binding to MHCII is strongly influenced by the pH and reducing potential of the cleavage environment as well as the flexibility of microdomains of the protein itself. Collectively, these results show that the cleavage events of antigen processing are pivotal to the generation of a broad and diverse peptidome available for binding to MHCII, and presentation to T-cells, that may lead to a more robust adaptive immune response.
    • Reevaluating recent temporal trends in animal body size: the role of demography

      Theriot, Miranda K.; Olson, Link; Doak, Patricia; Millien, Virginie (2021-05)
      Climate change over recent decades is associated with varied responses in animals, including both increases and decreases in body size. These opposing trends are often attributed to two primary hypotheses. In warm-blooded vertebrates, Bergmann's rule predicts decreases in average size with increasing temperature, based on the relationship between body size and thermoregulation. Alternatively, increased average body size is linked with changes in resource availability as summer growing seasons lengthen and winters becomes milder. We propose a third explanation, that shifts in demography underlie some of these observed trends, as many species change in size or shape throughout life. The influence of thermoregulatory demands, resources, and demography on body size trends are not mutually exclusive; disentangling these effects and identifying overarching patterns requires detailed analyses across multiple locations and taxa, which in turn necessitates repeatable and expandable studies. To that end, here we propose three best practices in body size research: defining and justifying measures of size, citing museum specimens, and accounting for demography. We employed these guidelines in a study on masked shrews (Sorex cinereus) in Alaska. We found evidence of age-based differences in total body length, tail length, skull length, and skull width; however, correcting for age did not have a strong effect on the apparent trends in size over time. Based on linear mixed models, mean total length and tail length increased from 1951-1991, consistent with previous findings. Additionally, our results revealed slight increases in mean skull length and toothrow length over the 40-year study period. There was some indication of differing trends between age classes in both of these measurements. These results were not statistically significant, but our sample size of overwintered adults was relatively small, so further study is needed to fully investigate age-specific size trends in masked shrews. In summary, this thesis highlights the importance of repeatability in body-size research and emphasizes the importance of demography in the study of these trends.