• The effects of individual and environmental heterogeneity on long-term population dynamics of Cassin's auklets (Ptychoramphus aleuticus)

      Johns, Michael E.; Breed, Greg; Lindberg, Mark; Kitaysky, Alexander; Doak, Pat (2020-12)
      Reproductive output and survival are expected to be balanced through a tradeoff between current success and future potential, in response to environmental conditions that vary on spatial and temporal scales. Long-term datasets that follow uniquely marked animals through time are excellent tools for describing how heritable or derived traits that influence reproduction and survival can be attributed to individual quality, and how the added reproductive performance of these individuals influence population dynamics. A 37-year record of breeding histories from known-aged Cassin's auklets from Southeast Farallon Island, a colony off the coast of central California, was used to examine these ideas in the context of a behavior unique to long-lived birds called double brooding. The results of generalized linear mixed modeling and multistate mark-recapture models revealed that double brooding, a form of increased immediate breeding effort, was associated with both higher reproductive output and longer lifespans. Older individuals that initiated breeding early in the season were most likely to attempt a second brood, particularly when food availability was high. Multistate mark-recapture analyses showed individuals that double brooded many times throughout their lives incurred no apparent longterm costs to survival or longevity. Oceanographic conditions related to prey abundance in the summer months affected the rates of double brooding, and using three years of movement data were shown to be important drivers of winter habitat selection as well. Findings at the individual level present strong evidence of a positive relationship between double brooding and survival that can only be attributed to some measure of individual quality. At the population level, when competition for breeding sites was relaxed, higher rates of double brooding had a positive effect on future recruitment rates; buffering the population against climate-driven periods of low adult survival.
    • Effects of sea ice seasonal evolution and oil properties on crude oil upward migration through sea ice

      Oggier, Marc; Eicken, Hajo; Collins, Eric; Barnes, David L.; Pettit, Erin; Truffer, Martin (2020-12)
      Sea ice plays an essential role in polar ecosystems as a habitat for organisms at the base of the food web. Receding Arctic perennial sea ice, potential oil and gas reserves, and increasing industrial activities in the Arctic are likely to increase oil extraction and transport in the maritime Arctic. Despite a decrease in summer sea ice extent, Arctic waters remain covered with sea ice for much of the year, increasing the risk of an oil spill in and under Arctic sea ice. This dissertation addresses the need for a quantitative understanding of the timing of and constraints on oil mobilization through the full seasonal cycle as well as the resulting oil distribution within the ice cover. All of these factors have major implications for spill clean-up efforts and habitat damage assessments. In Chapter 1, I assemble sea ice physical properties derived from long-term observations to characterize sea ice seasonal development stages. In Chapter 2, guided by results from three sets of oil-in-ice tank experiments, I present a semi-empirical multistage oil migration model linked to sea ice seasonal stages. I also find that ice stratigraphy plays a major role in oil movement, with granular ice hindering oil movement. In Chapter 3, I quantify the microstructural differences between granular and columnar ice texture. While both pore spaces have similar pore and throat size distribution, the higher tortuosity of granular ice increases the distance oil and brine have to travel by up to 30% to cover the same vertical distance as in columnar ice. With a less connected pore space, granular ice permeability is estimated as one order of magnitude smaller than that of columnar ice during winter and at the onset of spring warming. Chapter 4 introduces a simple 1D vertical model with a small set of initial conditions to describe oil movement along a connected pore pathway, I constrain the oil flow by accounting for the lateral displacement of brine into the surrounding ice volume to improve prediction of the timing and distribution of oil-in-ice flow. Future coupling of this model to a model of ice growth and melt may help inform oil spill response and clean-up operations, and improve the understanding of oil migration in the context of natural resource damage assessments.
    • Efficient alternative food systems for earth and space

      Alvarado, Kyle A.; Denkenberger, David; Schiewer, Silke; Karlsson, Meriam (2020-12)
      Alternative foods are a source of human-edible calories derived from an unconventional source or process. This thesis includes two alternative foods: (i) crops grown under low-tech greenhouses in low sunlight environments and (ii) hydrogen-oxidizing bacteria (HOB) in space and Earth refuges, such as to repopulate the Earth. The purpose of alternative foods is to ensure food security for human survival. During a global catastrophic risk (GCR) scenario, such as nuclear winter or super volcanic eruption, the sun may be obscured, causing lack of crop production and therefore global food shortages. The purpose of this thesis was to improve the cost and energy use of producing food during a GCR by avoiding the need to use artificial light photosynthesis. As a solution, a low-tech greenhouse scaling method was designed that could feed the Earth as quickly and cost-effectively as possible during a GCR, such as nuclear winter. Using concepts derived for scaling HOB single cell protein (SCP), a cost analysis was conducted for space that relates to Earth refuges. The cost of HOB was compared to that of microalgae SCP and of dry prepackaged food in a closed-loop system. Low-tech greenhouses were designed with basic materials to continue the production of non-cold tolerant crops at low cost; cold tolerant crops would be able to grow outside of greenhouses where it does not freeze. Scaling of low-tech greenhouses, which would add a cost to food of $2.30 /kg dry, is currently one of the most effective alternative foods for Earth. HOB is an effective method of converting electrical energy into food, having an electricity to biomass energy conversion efficiency of 18% versus 4.0% for artificial light (vertical farming) of microalgae (other crops would be even less efficient).
    • Enhancing tumor antigen presentation with complement targeted liposomes

      Francian, Alexandra; Kullberg, Max; Kuhn, Thomas; Burkhead, Jason; Knall, Cindy (2021-08)
      Tumor-mediated immune evasion and suppression can be prohibitive to successful cancer treatment and recovery. A defining trait of cancer progression is when tumor cells develop the ability to evade detection by the immune system. Advanced tumors can suppress the presentation of antigens to effector immune cells by secreting regulatory cytokines and by downregulating the expression of major histocompatibility complex I (MHC I) receptors on the surface of tumor cells. Effective anti-tumor immunity requires the processing and persistent presentation of tumor antigens to effector cells. The cells responsible for this are antigen presenting cells (APCs), which initiate the immune response against cancer by engulfing and presenting tumor antigens to effector immune cells. APCs present tumor antigens, which provide specific targets for helper T cells and cytotoxic T lymphocytes, allowing the immune system to distinguish cancer cells from noncancerous cells. There are many different types of tumor antigens, and the increased effort to sequence reactive epitopes and establish a database makes tumor antigen immunotherapy a promising avenue for treatments and vaccines. Immunotherapies have been developed to restore the immune response against tumors without the toxic side effects of chemotherapeutic drugs. This research describes a promising cancer immunotherapy utilizing a liposome nanoparticle that binds to endogenous complement C3 proteins in serum and is internalized by APCs through the complement C3 receptor, resulting in direct delivery of encapsulated compounds. APCs were shown to internalize C3-bound liposomes containing ovalbumin (OVA), a model antigen, resulting in a significant increase in activated T cells that recognize OVA, reduced tumor growth in all mice (n=5), and complete elimination of both treated and distal tumors in two out of five mice (40%). Blood from treated mice had lower percentages of immunosuppressive cells, higher percentages of B cells, and increased anti-OVA IgG1. Collectively, treatment with OVA C3-liposomes is able to induce the activation of both cell-mediated and humoral immune responses. C3-liposomes encapsulating a melanoma tumor antigen, TRP-2, were able to reduce and eliminate established tumors in a melanoma tumor model in 6 out 7 mice (86%), with the addition of checkpoint blockade, anti-CTLA-4, improving the results (tumor reduction in all mice; n=3). C3-liposomes were also able to induce expression of costimulatory molecules and the production of proinflammatory cytokines and factors in targeted APCs. These results indicate that C3-liposome delivery of tumor antigens to APCs initiates a potent and systemic antitumor immune response.
    • Environmental drivers of fish communities and food webs in Gulf of Alaska estuaries

      Lundstrom, Nina; Beaudreau, Anne; Mueter, Franz; Konar, Brenda (2021-05)
      The coastal Gulf of Alaska (GOA) is experiencing rapid, climate-driven ecological change. Climate forecasts predict increased temperatures and more precipitation as rainfall, but these changes will not have uniform effects across nearshore ecosystems. Estuarine habitats will be dynamically affected by changes in neighboring watersheds as glaciers melt and recede. Because estuaries provide critical habitat for many fishes, including some that support fisheries, it is important to understand how changing estuarine conditions may impact nearshore fish communities. The overall goal of this thesis was to investigate how environmental conditions, fish communities, and food webs vary across estuaries fed by watersheds with varying glacial coverage (0-60%). We conducted monthly beach seining and measured environmental conditions from April to September 2019 at ten estuary sites in two regions of the GOA, Lynn Canal in southeastern Alaska and Kachemak Bay in southcentral Alaska. The goal of Chapter One was to characterize differences in estuarine fish communities along the glacial gradient, between regions, and throughout the sampling season. We then focused on two abundant species in Lynn Canal, starry flounder (Platichthys stellatus) and Pacific staghorn sculpin (Leptocottus armatus), and used multiple years of data (2014, 2016-2017, 2019) to determine environmental drivers of size structure for each species. Fish communities showed the greatest differences between regions and across months, and temperature and salinity were significant drivers of variation in species composition. Variation in mean length of Pacific staghorn sculpin was best explained by year and the interaction of site and month, whereas variation in mean length of starry flounder was best explained by temperature, salinity, and turbidity. The goal of Chapter Two was to provide foundational information on the diet of juvenile coho salmon (Oncorhynchus kisutch) during the estuarine life stage and characterize variation in diets between years and regions. Juvenile coho salmon have a diverse diet of terrestrial and marine invertebrates and fishes, and they exhibited a shift to piscivory during this transitional period in nearshore habitats. Site differences accounted for most of the variability in diet, while temperature and salinity only accounted for a total of 12% of the variability in diet. Overall, we found that fish communities in GOA estuaries vary with environmental and habitat conditions, but that the glacial to non-glacial watershed gradient was less important in explaining variation in fish community structure than regional and interannual differences.
    • 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.
    • Ethnoarchaeology of the middle Tanana Valley, Alaska

      Smith, Gerad M.; Reuther, Joshua; Kari, James; Holmes, Charles; Hanson, Diane (2020-12)
      This study explores the shifting anthropological constructs of identity for the Middle Tanana people through time. It first summarizes this theme through contemporary regional Native American internal and external influences. A discussion is then given on how these constructs became formed through historical processes. Next, it provides an in-depth look into how identity became shaped prior to the Euro-American influence through an ethnographic reconstruction. These are framed in a way to form relevant hypotheses to study the regional prehistoric archaeological record. The Historical Linguistics analytical approach used here confirms that there is very little, if any, evidence in the languages of the Tanana Valley from any non-Dene or other hypothetical pre-existing linguistic group. Language forms an integral unit of community identity. This study also frames the linguistic argument for deep regional cultural antiquity and identity through an extensive survey of traditional place names. A brief comparative study of the processes and effects of the incursion of the Indo-European languages into traditional Dene territory is discussed to demonstrate this argument. Next, the research explores the middle and later Holocene archaeological record of the Shaw Creek basin, located deep within the Middle Tanana homelands, using innovative approaches framing traditional Optimal Foraging theory arguments through the lens of Complexity theory. It focuses on the household archaeology and spatial artifact analysis of two archaeological sites, Swan Point (three Holocene components) and Pickupsticks (one Holocene component). In these case studies, cultural identity analogs, social structure, and agency are discussed using the material cultural record as a proxy. Finally, a dynamic, seasonal, ecological landscape-use model informed by predator/prey interactions is used to inform hypothetical human foraging movements. It models decision-making and risk-mitigation processes through resource shortfalls, predicting raw materials' movements from their source locations to their discard locations at these two archaeological sites. The conclusions support the theory that Dene presence in the Middle Tanana Valley is an ancient phenomenon that has at least early Holocene roots. Further, the period between 2,000 and 1,000 years ago appears to have been a critical period of additional cultural intensification processes. The processes leading to the development of the Athabascan archaeological tradition are considered to be the result of demographic expansion, increased territoriality, and a critical reinterpretation of the roles of kinship and non-related partnerships.
    • An evaluation of GPR techniques for analyzing the safety of Interior Alaskan ice roads under varying river ice and environmental conditions

      Richards, Elizabeth M.; Stuefer, Svetlana; Maio, Chris; Belz, Nathan; Daanen, Ronald (2021-05)
      Ice roads and bridges are necessary routes to transport heavy equipment, supplies and food in the winter months to and from isolated cold region communities off the road system. Ice roads allow for community members to avoid the high costs of air shipments and obtain equipment and vehicles that would otherwise not be available. These ice roads traverse frozen bodies of water (e.g., rivers, estuaries, and lakes), and require extreme safety when driving over. To achieve this, calculations are frequently completed to determine the maximum acceptable loading on the ice cover. River ice tends to have increased safety concerns and uncertainty for travel that stem from warmer air temperatures and other factors such as precipitation, snow drifting, and ice cover forming differently each year. The necessity of obtaining time intensive ice thickness measurements by hand puts the responsible personnel at considerable risk of injury or fatality. Ground penetrating radar (GPR), which has gained much popularity in the last few decades, is a quicker and more effective non-invasive method for measuring ice thickness and other properties. The GPR system was tested for its accuracy in measuring ice thickness on common transportation routes on the Yukon River and the Tanana River. Identification of varying ice type layers in river ice cover using GPR was also attempted. While layers could not be identified using the 450 MHz and 750 MHz central frequency antennas, an accuracy analysis of GPR ice thickness measurements under various environmental conditions was completed. This analysis contributes to a comprehensive understanding of the safety of ice roads for community members in remote northern villages and provides the basis for further research on identifying layers in river ice cover.
    • Even in Arcadia: stories

      Wood, Rebecca N.; Farmer, Daryl; Johnson, Sara; Schell, Jennifer (2021-05)
      Even in Arcadia: Stories is a short story collection that follows adolescent and young adult women as they navigate growing up and growing out of the spaces they inhabit. Set in the American southwest, specifically unnamed suburban and rural cities of Arizona, the collection challenges the culturally popular narratives that surround the West-- the idealized cowboy, rugged individualism, and conquest of nature. Drawing on long-standing myths, serialized TV shows, and classic literature, the collection asks the reader to evaluate the stories they consume and are willing to take as truth. The stories range from realistic to speculative, employing horror and surrealistic elements as they descend into a sort of hellscape that draws on natural elements of desert landscapes juxtaposed against urban spaces. The collection focuses on gender, adolescence, and trauma set in the aftermath of the 2008 recession and the decline of small-town America from the perspective of youth.
    • Experimental investigation of polymer induced fouling of heater tubes in the first-ever polymer flood pilot on Alaska North Slope

      Dhaliwal, Anshul; Dandekar, Abhijit; Zhang, Yin; Goering, Douglas J. (2021-08)
      Mineral fouling in heat exchangers has been extensively investigated by researchers in recent times. The oil and gas industry has a long history of fouling issues in production systems as a result of produced fluids treatment. Due to decline in production rates in oilfields new technologies are being developed and field tested in pilots. Polymer flooding is one such technology that involves addition of polymers to injection fluids to enhance oil production. A polymer flood pilot has been set up in the Schrader Bluff viscous oil reservoir at Milne Point field on the Alaska North Slope (ANS). The results from the pilot are encouraging, however a major concern of the operator is the influence of polymer on the production system after breakthrough, especially the fouling in heat exchangers. This study investigates the propensity of polymer fouling on the heater tubes as a function of different variables, with the ultimate goal of determining safe and efficient operating conditions. This work applies a multi-experimental approach to study the severity of polymer-induced fouling in both dynamic and static states of produced fluids as well as studying the stability of polymer solutions at different temperatures. A unique experimental setup was designed and developed in-house to simulate the fouling process on the heating tube. The influence of heating tube skin temperature, tube material, and polymer concentration on fouling tendency was investigated. Each test was run five times with the same tube, and in each run, the freshly prepared synthetic brine and polymer solution was heated from 77°F to 122°F to mimic field-operating conditions. The heating time and fouling amount were recorded for each run. Dynamic Scale Loop (DSL) tests were conducted to study fouling due to polymer at different temperatures (165°F to 350°F) in a dynamic state of fluid flow where the fluids mimic the residence time of fluids in the heat exchanger on the field pilot. Cloud point measurement has also been conducted to find the critical temperature at which the polymer in solution becomes unstable and precipitates out. The morphology and composition of the deposit samples were analyzed by environmental scanning electron microscopy (ESEM) and X-ray diffraction (XRD), respectively. It was found that the presence of polymer in produced fluids would aggravate the fouling issues on both carbon steel and stainless-steel surfaces at all tested skin temperatures. Only higher skin temperatures of 250°F and 350°F could cause polymer-induced fouling issues on the copper tube surface, and the fouling tendency increased with polymer concentration. At the lower skin temperatures of 165°F, no polymer-induced fouling was identified on the copper tube. A critical temperature that is related to the cloud point of the polymer solution was believed to exist, below which polymer-induced fouling would not occur, and only mineral scale was deposited but above which the polymer would aggravate the fouling issue. The cloud point of the tested polymer solution was determined to be between 220°F and 230°F. In the DSL tests it was found that at higher skin temperatures of 250°F and 350°F tube blocking was observed in the DSL tests whereas the tests at 165°F and 200°F did not show any tube blocking in the same time period. These experiments also manifested the influence of cloud point of the solution as deposit rate increased significantly in both carbon steel and stainless-steel tubes when the skin temperature was higher than the solution cloud point. The results of this study have provided guidance to the operator for the field-operations.
    • Experimental investigation of the role of different clays in low salinity waterflooding

      Ivuawuogu, Henry; Zhang, Yin; Dandekar, Abhijit; Khataniar, Santanu; Awoleke, Obadare (2020-08)
      Various studies have demonstrated that Low Salinity Water Flooding (LSWF) can enhance oil recovery effectively, and its typical recovery mechanisms have been recognized. However, there is still a significant debate on the functions of clay during LSWF. This study investigates the impact of different clays, including montmorillonite, illite, and kaolinite, on the performance of LSWF. The zeta potentials of sand, montmorillonite, illite, and kaolinite in the presence of high salinity water (HSW) and low salinity water (LSW) were first examined. Then, the swelling factors of the three clay minerals in the HSW and LSW were measured in succession to determine their swelling characteristics. Subsequently, coreflooding experiments were conducted using one clay-free sand pack column and five sand pack columns respectively containing 10 wt% of montmorillonite, 10 wt% of illite, 10 wt% of kaolinite, compound clays (5 wt% of montmorillonite + 2.5 wt% of illite + 2.5 wt% of kaolinite), and 5 wt% of montmorillonite and the cumulative oil production and pressure drops were recorded. A produced crude oil sample with the American Petroleum Institute (API) gravity of 34° and viscosity of 14 cP (60°F) was used in the experiments. The total dissolved solids (TDS) of the HSW and LSW are 27,501 mg/L, and 2,485 mg/L respectively. It has been found that LSW could generate more negative zeta potential values for sand, montmorillonite, illite, and kaolinite, which made them more water-wet and thus favor oil recovery. Montmorillonite obviously swelled in HSW, and it could further swell significantly by contacting LSW. Although illite showed some swelling in HSW, LSW could not further expand it. Kaolinite did not swell in both HSW and LSW. The results from six coreflooding experiments showed that after high salinity waterflooding, the subsequent LSWF could generally further improve the oil recovery. The sand pack columns containing montmorillonite showed higher incremental oil recovery during LSWF (17.42% from sand pack column with 10 wt% of montmorillonite, 10.27% from sand pack column with compound clay, and 8.90% from sand pack column with 5 wt% of montmorillonite). Also, LSWF could improve oil recovery for the clay-free sand pack column, the sand pack column with kaolinite, and the sand pack column with illite by 0.73%, 0.83%, and 1.03%, respectively. Therefore, clay minerals would play an important role in determining oil recovery performance in LSWF, and the more swelling there is in clay in LSW, the more favorable it is in LSWF. This study proved that both clay swelling and wettability alteration could attribute to the improved oil recovery by LSWF.
    • Exploring infrasound wavefields to characterize volcanic eruptions

      Iezzi, Alexandra M.; Fee, David; Tape, Carl; West, Michael; Izbekov, Pavel; Haney, Matthew (2020-08)
      Infrasound has become an increasingly popular way to monitor and characterize volcanic eruptions, especially when combined with multidisciplinary observations. Regardless of how close the infrasound instruments are to the eruption, the effects from propagation must be considered prior to characterizing and quantifying the source. In this dissertation, we focus on modeling the effects of the atmosphere and topography on the recorded infrasound waveforms in order to better interpret the acoustic source and its implications on the volcanic eruption as a whole. Alaska has 54 historically active volcanoes, one third of which have no local monitoring equipment. Therefore, remote sensing (including that of infrasound arrays) is relied upon for the detection, location, and characterization of volcanic eruptions. At long ranges, the wind and temperature structure of the atmosphere affects infrasound propagation, however, changes in these conditions are variable both in time and space. We apply an atmospheric reconstruction model to characterize the atmosphere and use infrasound propagation modeling techniques for a few recent eruptions in Alaska. We couple these atmospheric propagation results with array processing techniques to provide insight into detection capability and eruption dynamics for both transient and long-duration eruptions in Alaska. Furthermore, we explore the future implementation of this long-range infrasound propagation modeling as an additional monitoring tool for volcano observatories in real time. The quantication of volcanic emissions, including volume flow rate and erupted mass, is possible through acoustic waveform inversion techniques that account for the effects of propagation over topography. Previous volcanic studies have generally assumed a simple acoustic source (monopole), however, more complex source reconstructions can be estimated using a combination of monopole and dipole sources (multipole). We deployed an acoustic network around Yasur volcano, Vanuatu, which has eruptions every 1-4 minutes, including acoustic sensors along a tethered aerostat, allowing us to better constrain the acoustic source in three dimensions. We find that the monopole source is a good approximation when topography is accounted for, but that directionality cannot be fully discounted. Inversions for the dipole components produce estimates consistent with observed ballistic directionality, though these inversions are somewhat unstable given the station conguration. Future work to explore acoustic waveform inversion stability, uncertainty, and robustness should be performed in order to better estimate and quantify the explosion source. Volcanic explosions can produce large, ash-rich plumes that pose great hazard to aviation. We use a single co-located seismic and infrasound sensor pair to characterize 21 explosions at Mount Cleveland, Alaska over a four-year study period. While the seismic explosion signals were similar, the acoustic signals varied between explosions, with some explosions exhibiting single main compressional phase while other explosions had multiple compressions in a row. A notable observation is that the seismo-acoustic time lag varied between explosions, implying a change in the path between the source and receiver. We explore the influence of atmospheric effects, nonlinear propagation, and source depth within the conduit on this variable seismo-acoustic time lag. While changes in the atmospheric conditions can explain some of the observed variation, substantial residual time lags remain for many explosions. Additionally, nonlinear propagation does not result in a measurable difference for the acoustic onset. Therefore, using methods such as seismic particle motion analysis and cross correlation of waveforms between events, we conclude that varying source depth within the conduit likely plays a key role in the observed variation in the seismo-acoustic time lags at Mount Cleveland.
    • Exploring the use of machine learning for daily fire growth prediction in Alaska

      White, James; Walsh, John; Thoman, Richard; Bhatt, Uma (2021-05)
      Wildfire is a natural but often hazardous part of the Alaskan ecosystems. Physically based wildfire models range from simple relationships used for rapid, in-situ fire behavior analysis to complex weather models used for prediction over several days and weeks. Physical models in Alaska, however, often struggle to integrate weather forecast information to make predictions beyond just a few days. The random forest model explored here is able to leverage an array of variables to identify days of enhanced and reduced satellite fire detections. Peaks and lulls in activity are accurately identified, though exact magnitudes are often incorrect, especially when wildfire suppression efforts occurred. This study emphasizes the use of reanalysis weather variables in addition to antecedent fire activity, highlighting the usefulness of variables like vapor pressure deficit for use in quantitative prediction. By applying weather forecast data, the model generated simulated wildfire forecasts. These forecasts show some success at identifying peaks and lulls in fire activity. Effective lead time varied widely ranging between 1 and 10 days, mostly dependent on the weather model performance. By providing specific timing and using real ensemble forecasts for medium term prediction, a model likes this fills a potential open niche in fire predictive services. Machine learning may be especially useful for its relative efficiency and ease of automation.
    • Fate and effects of commercial crude oil bioremediation products in Arctic seawater

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

      LaMesjerant, Eric N.; Toniolo, Horacio; Barnes, David; Shur, Yuri (2020-12)
      Alaska is characterized by sparse hydrologic data. Non-intrusive gauging is one method of increasing the data available but is limited in its current application. This study seeks to assess the feasibility of using commercially available software and multiple cameras to diversify the conditions for which large-scale particle image velocimetry may be applied. Using available software and the deployment of multiple cameras, stereoscopically determined discharge is compared with discharge determined using an acoustic Doppler current profiler and accepted single camera practices currently in use with large-scale particle image velocimetry. The results indicate that the use of commercial software and multiple cameras is feasible, with additional work, and that there is a statistically significant relationship between the velocity index (alpha) and aspect ratio (B/H, width divided by average depth). The velocity index-aspect ratio data indicate that the velocity index is a result of the environmental and geometric conditions for a given cross section and that an empirical relationship could be established.
    • Genomic signatures of optimal growth temperature in the family Colwelliaceae

      Gentilhomme, Anais; Collins, R. Eric; Hennon, Gwenn M.M.; Leigh, Mary-Beth; Drown, Devin (2020-12)
      The temperature range supporting growth defines a complex physiological phenotype that depends on interactions between an organism's genome and its environment. Its implications are widespread since small changes in optimal growth temperature (OGT) can alter an organism's ability to inhabit an ecological niche. Thus, organisms with extreme thermal growth traits (e.g., psychrophilic, with OGT < 15℃, or thermophilic, with OGT 60 -80℃) may be useful for identifying promising targets when searching for life on other planets, as well as predicting population dynamics in a warming Arctic. We performed comparative genomic analyses of bacteria newly isolated from Arctic sea ice that were affiliated with Colwelliaceae, a family of Gammaproteobacteria that contains many psychrophilic strains, to identify genomic factors that might be used to predict OGT. A phylogenomic analysis of 67 public and 39 newly-sequenced strains, was used to construct an updated phylogenetic tree of Colwelliaceae, of which at least two genera were well represented. To augment the previously reported OGTs of 26 strains, we measured growth rates at −1, 4, 11, and 17 ℃ to determine the OGTs of these 39 new strains of Colwelliaceae. We found that growth rates among all isolates were comparable at −1℃, but varied widely above 10 ℃, indicating higher variability in the ability to tolerate warmer temperatures. To analyze the phenotypic differences on a genomic level, we examined indices of amino acid substitutions that have previously been linked with cold adaptation via an increase in protein flexibility. We found that these indices were significantly correlated with OGT at the whole genome level, although the sign of some correlations were opposite of the predicted positive correlation between temperature and the indices. Using these data, we fit a multiple linear regression model for OGT within the Colwelliaceae family that incorporates the three most informative amino acid indices: GRAVY, Aliphatic Index, and Acidic Residue Proportion. Additionally, a putative cold-adaptive gene cassette was identified that was likely introduced by horizontal gene transfer between two closely related clades with different OGTs. These contributions offer key insights into OGT variability and its underlying genomic foundation in the family Colwelliaceae.
    • Geochemical, spatial, and temporal relationships of the intrusives and meta-intrusives of the Pogo deposit, eastern Interior, AK

      Thompson, William D.; Newberry, Rainer; Keskinen, Mary; Mezger, Jochen (2020-12)
      The Pogo deposit is an intrusion-related gold deposit (IRGD) located approximately 90 km southeast of Fairbanks, Alaska. It consists mainly of shallowly NW dipping quartz veins hosted in amphibolite facies paragneiss and predominately granite orthogneiss bodies. To date the deposit has produced over 4 million ounces of gold. U-Pb zircon dating of the orthogneisses shows they have Devonian-Mississippian protolith ages. Dates from the metamorphic zircons, established by microprobe Th data and cathodoluminescence studies, constrain a mid-Cretaceous metamorphic event to ~116 Ma. Recrystallization of kyanite to sillimanite and zircon recrystallization indicates this was a large fluid flux event that predated mineralization by 10 million years. Due to the fine-grained nature of the intrusive rocks at Pogo, identifying rocks in hand sample proved problematic. By combining XRF analysis of the rocks' major and trace elements and age data from this and previous studies, I identified and differentiated several suites of igneous rocks. The oldest is peraluminous granite, emplaced at ~2.5 ± 0.5 kb at ~109-107 Ma, predating mineralization at 104 Ma at a pressure of 2.0 kb. Non-peraluminous granite is less common and of uncertain relationship to the peraluminous granite. Next, temporally, is a body named the Football pluton (and associated dike) of granodioritic to tonalitic composition, emplaced at 2.0 ± 0.5 kb at 103 ± 2 Ma. Not only indistinguishable from age and depth of mineralization, a dike of this body is present downdip underneath the Liese veins (main zone of mineralization), making it the most likely candidate for being the causative pluton for mineralization. The final mid-Cretaceous body is the Liese pluton (and associated dikes), of quartz diorite to tonalite. This forms a large body with E-W dikes cutting the Pogo mineralization and post-dating it at 95.4 ± 0.2 Ma, emplaced at a pressure of 1.0 kb. Thermobarometry and radiometric dating indicate a consistent uplift rate of about 0.6 mm/year during the mid-Cretaceous, 116 to 95 Ma. Initially an extensional event, subduction-related magmatism began at about 105 Ma. At the same time, the thrust faults were re-activated as low angle normal faults that apparently acted as pathways for the Liese mineralization.
    • Gravity and mountain waves and their phenomena in Fairbanks, Alaska: a comparative case study

      Brink, Hannah; Mölders, Nicole; Fochesatto, Javier; Polyakov, Igor; Newman, David (2021-05)
      The area of Fairbanks, Alaska is in a valley surrounded by mountains from the Alaska Range to the South, the Brooks Range to the north, and the eastern mountain range that extends into Canada. The topographical nature of this subarctic area brings unique atmospheric features to the Fairbanks area, such as temperature inversions and mountain wave perturbation. This thesis will examine two case studies of gravity wave phenomena; one a mountain wave from December 2017, the other a non-mountainous gravity wave from December 2016. Data was collected from radiosondes and Global Data Assimilation Model (GDAS) maps, with the former smoothed for comparative purposes. Profiles of the atmosphere were created to see direct changes that mountain waves create on atmospheric parameters and the subarctic valley area. Methods were explored to separate mountain wave buoyancy effects from other atmospheric buoyancy effects, and then used to compare mountain wave buoyancy effects with frontal motion buoyancy effects. In all cases, the polar jet stream was found to have signicant influence on gravity wave effects in the Fairbanks area. Attention to the polar jet stream location can help predict mountain wave effects and associated atmospheric perturbations. Weather phenomena localized by altitude due to gravity waves were also identified. These include localized short-term surface pressure systems on the day of gravity wave cases. Mountain waves were found to be strongly linked to synoptic temperature events in Fairbanks, Alaska, and the mountain wave case was found to have more pronounced atmospheric effects than the gravity wave case.
    • 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.
    • Habitat use of spectacled eider broods in relation to salinity and food availability on the Yukon-Kuskokwim Delta, Alaska

      Graff, Nathan R.; Lindberg, Mark; Hollmén, Tuula; Knut, Kielland (2021-08)
      Spectacled eiders (Somateria fischeri) nest and raise their broods in coastal areas of the Yukon-Kuskokwim Delta, which may be vulnerable to projected climate change effects of increased temperatures, storms, and sea level rise. These changes in turn will likely affect wetland salinity levels used by ducklings, which are a potential constraint to growth and survival of young ducklings while their salt glands develop. To examine this potential concern, I investigated spatial and temporal pond salinity dynamics, food availability, and habitat use of spectacled eider broods at Kigigak Island, AK during 2011-2012. I found that salinity was highly variable across the island, ranging from 0-23.9 ppt and averaged 4.9-12.9 ppt in ponds at brood observation sites during the first 30 days of brood rearing. Salinity typically increased through the summer across all habitat types, but at the highest rate in high sedge habitat. The most common invertebrate taxonomic groups included Eurytemora, Harpacticoida, Annelida, and Chironomidae, which were found in nearly all ponds sampled with salinity ranging from 0.7- 16.1 ppt. Neither salinity nor invertebrate abundance explained pond foraging use by broods. Additionally, I used robust design occupancy models to estimate brood foraging patterns. Pond occupancy ranged from 0.43-0.59 between years. Overall, brood use of ponds was not dictated by salinity levels or invertebrates present, suggesting that most ponds provide suitable brood rearing habitat. I did not detect any obvious constraint to pond use within brood rearing habitat under the environmental conditions encountered.