Presenter Abstracts 

Interactive limitation of organic carbon processing in boreal headwater streams

Frances Iannucci, University of Alaska Fairbanks graduate student

Carbon emission from headwater streams represents an important yet uncertain component of ecosystem C balance. Microbial respiration may be an especially important component in the boreal forest where stream metabolism is highly heterotrophic and organic C can comprise a large portion of total C inputs. Climate-induced changes in boreal watersheds (e.g., permafrost thaw) will undoubtedly alter C processing in stream networks through change in resource supply and hydrologic flow paths. However, the magnitude of responses to changing resource delivery will depend on variation in the resources limiting boreal stream metabolism. To determine the resources most important in regulating dissolved organic C (DOC) uptake in boreal streams, I conducted a series of biodegradable dissolved organic C (BDOC) uptake experiments throughout the Caribou-Poker Creeks Research Watershed (CPCRW) near Fairbanks, Alaska. DOC uptake was primarily limited by labile C availability throughout the watershed, and phosphorus availability further accelerated DOC uptake when labile C was available. Cold temperature strongly limited DOC uptake when P was low, but increased P availability counteracted this temperature limitation. The co-importance of temperature, DOC lability, and P availability suggests that the current ambient conditions in the CPCRW are not conducive to large microbial contributions to stream C emissions. However, microbial C processing and stream C emissions could increase with warmer stream temperature and increased labile C delivery as permafrost thaw progresses in boreal ecosystems.

Analyzing cod bone  and otoliths  to trace connections between  Icelanders and Atlantic cod over the last 1100 years

Habiba Moshfeka, University of Alaska Fairbanks graduate student

Cod (Gadus morhua) have been part of thriving North Atlantic fisheries for almost 1100 years, playing a pivotal role in Atlantic and global history, and it continues to be a key resource for food, economy and  trade. Existing cod populations are managed based on scientists' ideas of what constitutes a 'normal' or 'natural' cod population. This cod 'baseline' is largely based on data from the last 100-150 years. We can now extend this baseline data back over the millennium using techniques from a range of disciplines, including marine biology, archaeology, and history. Archaeology and historical ecology are in a unique position to analyze the long-term consequences of human/natural interactions. This is especially true when stable isotope (SI), ancient DNA (aDNA), zooarchaeological techniques (such as size and age assessments), and historical documents are combined. These methods can be used to investigate interactions between human subsistence, commercial harvests, and marine ecosystems. To examine these links, this project will use SI signatures (δ13C, δ18O and δ15N bulk and compound specific), allometric measurements of cod cranial elements, sea surface temperature (SST) reconstruction, growth rate, size-at-age estimates, and mortality rates from otoliths, as proxies to help determine changes in trophic position, productivity, foraging locations, and stock size and health  over time. Combined with SST from ocean cores and climate, harvest and trade data from historical documents, these new data will be useful in managing the human/cod relationship now and in the future.

Characterizing the immune response of trembling aspen to an aggressive fungal pathogen - infection decreases total RNA in trembling aspen trees

Hannah Glesener, University of Alaska Fairbanks undergraduate student

Neodothiora populina is a recently identified fungal pathogen that causes widespread mortality in Populus tremuloides. Transcriptomics on bark samples from P. tremuloides enable the characterization of the immune response of the tree to the canker. Using the Sigma Spectrum Plant Total RNA Kit I extracted total RNA from necrotic, infected, and neighboring healthy looking bark of infected trembling aspen trees as well as from bark of healthy aspen trees. I detected that necrotic, infected, and neighboring healthy looking bark of infected trembling aspen trees gave significantly less total RNA compared to neighboring healthy aspen trees rendering RNA sequencing of these types of bark samples difficult. Six test samples including infected bark and neighboring healthy looking bark as well as bark of healthy trees were sent to Psomagen for low input RNA sequencing. I identified target genes representative of the different stages of plant immune response to facilitate analysis.

A Dental Metric Biodistance Analysis of the Rong and the A'chik

Mary Stough, University of Alaska Fairbanks graduate student

Little is known about the population history and genetic affinities of many of the tribal groups of northeastern India, including the Rong and the A’chik. This study employs tooth size allocation analysis to test hypotheses concerning their origins and the impact of sex-biased post-marital residence patterns. Due to matrilineality and matrilocality, A’chik females ought to express less variability than males and be more isolated phenetically from members of other groups. The opposite should be true for the Rong who are patrilineal and patrilocal. Despite patrilineality, Rong females should share some affinities to members of other groups due to the widespread practice of hypergamous marriages. Mesiodistal and buccolingual dimensions of the permanent teeth were measured among 166 A’chik and 185 Rong individuals. These data were compared to that obtained among 1151 members of seven ethnic groups from other regions of South Asia. Group centroids from canonical variates were plotted in three dimensions to assess similarities among samples. Canonical variates, from both sex-pooled and non-pooled analysis, identify the Rong and A’chik as possessing closer affinities to each other than to members of the other groups, thereby supporting the hypothesis that members of these two tribal groups share a population history different from that of ethnic groups of other regions of the subcontinent. The sex-pooled analysis indicated a closer relationship between the Rong males and the A’chik and a more distant relationship between the Rong males and the other groups than expected. Overall the results support findings from genetic studies and population histories. 

Sled dog hair analysis in a pre- and post- salmon diet.

Shannon Jimmie, University of Alaska Fairbanks undergraduate student

The Role of Juvenile Weight in Predicting Age to Maturity for Moose Populations in Northwest Alaska

Sara Germain, University of Alaska Fairbanks graduate student

Capturing and weighing short-yearling moose (juveniles aged 9-11 months old) is standard practice for managers interested in assessing the health of a given population. However, little is known about the influence of short-yearling weights on specific moose population dynamics, such as calving rates. For this project, I sought to describe the relationship between a cow moose’s short-yearling weight and the age at which she begins calving by monitoring collared cow moose in two adjacent populations near Nome, Alaska. Preliminary data from two years of calving surveys indicate that cow moose that begin calving at 2-years-old weigh significantly more as short-yearlings than cows that begin calving at 3-years-old. Additionally, the short-yearling weight at which a cow moose had a 50% probability of calving as a 2-year-old differed between populations. These results suggest that short-yearling weight has lasting implications on the reproductive capacity of an individual moose and may provide managers with population-specific metrics to more accurately estimate whether a population is in decline.

Efficient Wet-Biomass Fuel Production Via Supercritical Water

Jonathan Kamler, University of Alaska Fairbanks graduate student

Broadly speaking, biomass refers to any organic matter from living organisms. Some biomass sources have longstanding histories as straightforward, reliable energy supplies (e.g., wood), whereas many others face critical impediments to viably supplying energy due in large part to high water content. In fact, some of the largest biomass sources are very wet and have therefore been largely dismissed as insurmountably impractical energy supplies. Historically, contending with wet biomass has singularly relied on suitable, water-removal methods sufficient to making the material burnable. Doing so has met with mixed success at best. Indeed, drying wet biomass often requires more energy than can ultimately be recovered. Unsurprisingly, less-practicality-challenged energy supplies have garnered the lions share of development effort given that up-side-down energy balances seldom pencil out well economically. That fact holds true despite the incongruous reality that many wet-biomass sources are energetically comparable to mid-grade coal on a dry tonnage basis. The trick is to flip the equation on its head and efficiently recover work-producing energy (a.k.a., exergy) from wet biomass without removing the water, which at face value sounds dubious. However, this research examines supercritical-water gasification processes to do exact that. Rather than removing the water, supercritical-water gasification uses the water as the medium to efficiently convert wet biomass directly to fuels. Notably, the research also aligns well with emerging industry optimization trajectories. Specifically, this research investigates supercritical-water process and hardware optimization, with preliminary results, discoveries, and insights having already produced multiple University of Alaska patents.

Anaerobic metabolic remodeling in three-spine stickleback fish in response to thermal acclimation

Eleanor Ransdell-Green, University of Alaska Fairbanks undergraduate student

Metabolic remodeling in organisms is critical for the maintenance of metabolic performance during extreme temperature changes. Thus, metabolic remodeling has become a primary focus in the field of biochemical adaptation in efforts to gain a better understanding of the mechanism. In this study, spectrophotometric assays were conducted to quantify the maximal activity of the glycolysis-associated enzyme lactate dehydrogenase (LDH) in the liver, oxidative muscle, and glycolytic muscle of the three-spine stickleback fish, Gasterusteus aculeatus, acclimated to 20℃, 12℃, and 5℃ temperatures. To detect changes in LDH activity and to determine if there is complete compensation in response to thermal acclimation, maximal LDH activity was measured at the acclimation temperature of the animal and at a common temperature of 20℃. When measured at the acclimation temperature, LDH activity in oxidative and glycolytic muscles were equivalent in all three temperature groups. However, in the liver, LDH activity was significantly higher in fish acclimated to 20℃ compared to fish acclimated to 12℃ and 5℃ temperatures. Measurements of LDH activity at a common temperature revealed no degree of thermal compensation in response to thermal acclimation in any of the three tissue types. When paired with results of previous studies showing significant thermal compensation in citrate synthase activity, these results indicate that G. aculeatus may be more reliant on aerobic metabolism at cold temperatures than anaerobic metabolism. The high level of variability in tissue LDH activity observed amongst individuals suggests that other confounding variables, such as those that determine energetic reserves, may be present. 

The Relationship of Substrate and Depth in Eastern Cook Inlet

Ruby Scanlon, University of Alaska Fairbanks undergraduate student

The sea otter, Enhydra lutris, is listed as threatened under the Endangered Species Act, and is designated as depleted under the Marine Mammal Protection Act. An important component in restoring the species is measuring and protecting their critical habitat. This project focuses on analyzing the substrate as it relates to depth in Eastern Cook Inlet, which supports a population of sea otters and is subject of several oil and gas lease sales. Sea otters predominantly utilize depths less than 40m. Prey availability can vary with depth and substrate, which could result in disproportionate depth usage by sea otters in variable habitats. Using a remotely operated vehicle (ROV), we recorded images at different depths between Anchor Point and Clam Gulch, to measure and predict sea otter usage and resource availability. After reviewing more than 1,300 images, we recorded eight different substrate types at the depths between 5 and 30 m. Of these substrates, the largest percentage was mud at 30.67%, and the lowest percentage was boulder at 1.76%. Substrate was found to be fairly consistent with depth, however sand cover was significantly different between 5 m and 30 m shell cover was significantly different between 5 m and 30 m. The results of this project can help to determine critical habitat for sea otters in Eastern Cook Inlet.

Moose habitat selection in the changing environment of southwest Alaska 

Sarah Dempsey, University of Alaska Fairbanks undergraduate student

In recent years, southwest Alaska has been evidence for climate change with its rising temperatures, varied sea ice, and increase in shrubs. Togiak National Wildlife Refuge (TNWR) is a 520,000 acre plot of protected land in this region, giving us a prime habitat to study. With this shifting environment, we observed that moose (Alces alces gigas) are taking advantage, with a 400- fold increase in population having occurred within TNWR. Curious about what specifically is making this moose population thrive, we performed a resource selection function (RSF) based on telemetry data of collared females in the area from 1998-2020. A moose’s primary source of nutrients comes from shrubs such as willow (Salix Salicacea), which are abundant in riparian areas. With the increase in shrubification, we hypothesize that elevation, distance from riparian area, National Land Cover Data (NCLD), and ruggedness will predict the relative probability of moose selection. We used analysis of variance (ANOVA) and Akaike’s information criterion (AIC) to compare models. A completed model and results have yet to be confirmed. 

A comparison of perceptions about the use of two different teaching pedagogies: Zoom, a video conferencing platform, and an experiential hands-on approach for teaching marine science in Bethel, Ak .

Courtney Pegus, University of Alaska Fairbanks graduate student

The 2019 novel coronavirus or COVID-19 pandemic had significant impacts on educational systems worldwide causing abrupt shifts in teaching pedagogies to be more centered on virtual or digital forms of teaching. It remains unclear how this format of teaching marine science will be perceived by students. Compared to in-person experiential teaching pedagogies, virtually- based pedagogies might increase levels of isolation by removing interpersonal and mentorship opportunities. To address this unknown we are examining students’ perceptions of a series of marine science classes that were held in Bethel, AK during the summer 2021. Summer science classes included virtual or “Zoom” classes as well as in-person teaching where subject materials were delivered by Elders as well as University professors.  We will use a mixed-method design to include results obtained from a questionnaire survey completed by instructors who led the classes as well as perceptions that were shared during the summer course.  The study will compare the attitudes and perceptions of individuals residing in rural villages in Alaska as well as teaching instructors who were introduced to the two types of teaching pedagogies during a marine science-oriented summer course. Results from this study will identify features of each teaching pedagogy that were appealing and meaningful to the class and help guide future science classes that are directed to marine science education in rural communities.

The Diversity of Mercury Methylating Bacteria Across a Permafrost Thaw Gradient in Interior Alaska

Jules Pender, University of Alaska Fairbanks undergraduate student

In this research project, we (Jules Pender, Dr. Mario Muscarella, Kaia Victorino) have been investigating the microbial diversity of soil bacteria and archaea in Interior Alaska, focusing specifically on whether they can methylate mercury and how this may change with respect to factors like thawing permafrost and wildfire events. Some anaerobic prokaryotes take up elemental mercury from the environment and methylate it in order to expel it. This methylmercury has a long biological half-life and can biomagnify to the top of food chains, posing environmental toxicity problems. Pertinent to Alaska’s rapidly changing climate, we hypothesized that locations with thawing permafrost or that had been recovering from wildfire would have a higher diversity of mercury methylating microorganisms and higher soil concentrations of methylmercury. This is because permafrost soils are the largest reservoir of mercury on the planet, and as they thaw, microbial activity increases, and this mercury is made available to them. Mercury is also mobilized from wildfires due to soil disturbance and atmospheric deposits. To study the distribution of mercury methylators, we collected 88 soil core samples from 26 sites in the Bonanza Creek LTER Regional Site Network and also at Big Trail Lake in the summer of 2021. From each sample, we extracted the DNA and amplified two genes of interest that were sequenced: the 16S gene to identify the microbes, and hgcA, which encodes a corrinoid protein essential for mercury methylation. Results are TBD.

Microbial community diversity in sediments and water from the Chena River 

Daphne Mueller, University of Alaska Fairbanks undergraduate student

I surveyed microbial community diversity in water and substrate samples to measure changes in those microbial communities along the Chena River. I used a metabarcoding approach to characterize my samples. I extracted DNA from my environmental samples and performed 16S amplicon sequencing. I will analyze community composition and compare samples by location and type. Microbial communities are markers for the health of their environments. Through the analysis of these communities, we can monitor coexisting plants and animals, and surrounding environments in freshwater habitats. 

Characterization of the onset of the 2021–2022 Great Sitkin dome-building eruption through the inversion of LP seismicity

Kyungmin Kim, University of Alaska Fairbanks graduate student

Long-period (LP) seismicity, which is commonly observed around active volcanoes, is thought to be controlled by the migration of magmatic or hydrothermal fluids. For example, Girona et al. (2019) found through a theoretical analysis that the permeable transport of gases can spontaneously trigger LP signals (and tremor) depending on gas supply characteristics and on the physical properties of volcanic conduits. This model, known as the gas pocket model, can be used to infer the physical properties of volcanic caps or domes by using methods such as the Bayesian Markov chain Monte Carlo inversion.  In this project, we focus on two open questions regarding LP signals and their relation to volcanic activity: (1) To what extent the gas pocket model can be applied to actual volcanoes for interpreting the physical properties of shallow vents? (2) Can an individual volcanic eruption be characterized through the inversion of LP seismicity? To investigate these questions, we run Bayesian Markov chain Monte Carlo inversions of the LP signals recorded at Great Sitkin volcano (Alaska) from July to early August 2021, which featured unrest and the onset of a new dome-building eruption. Our preliminary results showed that seismic attenuation increased between July 23–24, which can be interpreted as an increase of pressurized fluid and gas content in the shallow crust during the onset of the eruption;  and a decreased after July 25. Our analysis also reveals that the permeability of the dome during that period was constrained between 10^(-9) to 10^(-8) m^2.

The role of climate change in an expanding moose population in southwest Alaska

Sebastian Zavoico, University of Alaska Fairbanks graduate student

Climate change is altering the ecosystem structure of areas across the Arctic and sub-Arctic. One of the fastest-changing regions is southwest Alaska, where a combination of rising temperatures, shrubification, and increasingly inconsistent winter snowpack have occurred alongside a 400-fold increase in a moose (Alces alces gigas) population. We tested the hypothesis that climate change facilitated this population expansion by studying the population dynamics of a moose population in Togiak National Wildlife Refuge. We used a multistate model to estimate annual cow and calf survival, and parturition and twinning probabilities from monthly telemetry observations from 1998-2020. We embedded Generalized Linear Mixed Models (GLMMs) within the multistate model to test relationships between each demographic parameter and summer vegetation productivity (NDVI) and winter severity (WSI), two environmental metrics known to be changing due to climate change. We hypothesized demographic parameters would increase with higher NDVI and lower WSI and found support for these hypotheses. We found that summers with higher vegetation productivity, and winters with lower severity boost population productivity, lending support to the hypothesis that climate change is, at least in part, responsible for rapid moose population increase in southwest Alaska. Since moose act as important subsistence resources and ecosystem engineers, we recommend more research be done to understand how and why moose abundance is changing across the sub-Arctic and Arctic.

The role of antecedent moisture conditions in high-latitude catchment biogeochemistry

Jake Cavaiani, University of Alaska Fairbanks graduate student

High-latitude ecosystems are vulnerable to rapidly warming climate and increasingly variable precipitation resulting in altered pools and fluxes of materials from terrestrial to aquatic ecosystems. Permafrost-influenced soils store a significant portion of the global carbon (C) and nitrogen (N) stocks. As climate warming stimulates permafrost thaw, the fates of these released materials are critical for global C and N budgets. Permafrost thaw shifts hydrologic flowpaths from shallow, organic-rich soils to deeper, mineral-rich soils, which is hypothesized to diminish organic carbon and increase export of nitrate (NO3–) in high-latitude streams. Thus, solute dynamics in streams might reflect spatial and temporal patterns of permafrost thaw. However, solute exports also respond to short-term (e.g., inter-annual) variation in precipitation, which is also expected to increase under a warming climate, but the effects of antecedent moisture conditions remain less clear. Increased precipitation might promote solute leaching and establish hydrologic connectivity between catchments and streams, thereby reducing solute storage within catchments and facilitating rapid transport of solutes from distal sources to streams during storms. Transport mechanisms and solute storage can be estimated by observing differences in the concentration-discharge relationship between the rising and falling limbs of individual storm events (i.e., hysteresis). We monitored NO3– and fluorescent dissolved organic matter (fDOM) at high-frequency (15 min) intervals in six streams in Interior Alaska and quantified correlations between antecedent moisture conditions and storm dynamics. Storm dynamics indicated differential patterns of solute sources and transport across catchments varying in spatial extent of permafrost. 

Observer Variability in Dental Metrics

Sierra Cotrona, University of Alaska Fairbanks graduate student

Dental metrics are used by anthropologists to address questions in hominin evolution, biological distance analysis, population genetics, and the osteobiography in forensic anthropology and bioarcheology. Observer variability is inevitable but understanding the level in inter- and intra-user variability is important for repeatability. It is likely that there are certain teeth or measurements that are more subject to errors than others. The purpose of this study is to examine inter- and intraobserver variability in dental metrics in a cast collection from Northeast India. Some 50 plaster casts from the Hmar ethnic group were measured by three researchers during three measurement bouts each separated by a 30-day period. The researchers took mesiodistal (MD) and buccolingual (BL) measurements of 28 permanent teeth, except third molars (due to an inclusion protocol that limited participants to 15 – 19 years of age). Shapiro-Wilk tests was conducted for all variables to ensure normality of data. MANOVA tests were employed to determine significant differences regarding main effects and their interactions. Tukey HSD was used to test differences between the sample pairs. Results obtained from interobserver variation indicate that the researcher has little impact on the measurements obtained for incisor and molar data, or for MD measurements overall. Premolar BL measurements in both upper and lower arcades as well as maxillary canine and molar BL measurements yielded significant differences between researchers. This is likely due to slight differences in the orientation of this measurement relative to the long axis of the crown between observers.

Developing new movement models that combine GPS, heart rate, and accelerometry data to identify nuanced foraging behaviors of pelagic seabirds. 

Abigail Schiffmiller, University of Alaska Fairbanks graduate student

Accurately identifying behavior in free-living species is key to understanding how they interact with their environments and how ecosystem changes will affect such populations. However direct observation is often not possible, and wide ranging, free-living species are often only observable via biotelemetry. This is problematic for tasks such as detecting and understanding different foraging strategies in seabirds. Many seabirds engage in ‘facilitated foraging’ whereby marine predators (such as tuna and sharks) force aggregations of small fish near the ocean surface, increasing their accessibility to foraging birds. Understanding the importance of this foraging strategy to seabird populations is key to understanding how changes in marine predator populations may be linked to seabird population outcomes. To address this, we are developing models to analyze biologging data collected from birds carrying camera, position, and physiological instrument packages.  We will first model and identify the occurrence of different foraging behaviors, and then link the different foraging types to the presence of other predators and to the animal’s energy budgets from physiological biologger data. To do this, we will estimate behavioral parameters by modeling movement as a dynamic correlated random walk with time-varying correlation parameter controlled by environmental covariates. These models will be used to identify unique foraging behaviors during foraging trips, including facilitated foraging, ordinary foraging, and resting behaviors. The adapted model will include oceanographic covariates related to ocean productivity (such as fronts) and weather, as these variables influence the prevalence and detection of facilitated foraging opportunities.  Animal-borne camera and accelerometer data will be used to both develop and validate the behaviors delineated by the newly developed model. Once behaviors are identified, accelerometers, heart rate monitors, and stomach temperature loggers will be incorporated into the CRW model for finer discrimination and to assess the energetic consequences of each foraging type and to assess the overall importance of facilitated foraging on seabird energy budgets.

Biogeography and phylogeography of lake trout in Alaska

Anna Rix, University of Alaska Fairbanks graduate student

Understanding the historical dispersal of organisms across the landscape through genetics promotes enhanced prediction of distribution changes and conservation of wildlife populations. Cold-temperate freshwater fishes, such as the remarkably variable lake trout (Salvelinus namaycush) may provide information on how organisms have moved across the landscape and arrived at their present distribution in response to glacial cycling-mediated changes in freshwater connectivity. Previous work using restriction fragment length polymorphism (RFLP) analysis of mitochondrial DNA (mtDNA) in lake trout identified  four lake trout lineages that diverged  about 400,000 years ago and have colonized North America after glacial retreat. These lineages survived the Wisconsin glaciation in one or more refugia. Alaskan populations of lake trout were poorly represented in those analyses, however there appears to be two distinct lineages with one in the north and another in the south. What occurs in the drainages of interior Alaska is uncertain. To determine the mitochondrial lineage affinities of lake trout in interior Alaska, two mtDNA genes were sequenced revealing that interior Alaskan lake trout are most likely part of the southern Beringia lineage. However, Arctic drainages host populations with both the previously known northern Beringia lineage as well as the southern Beringia lineage. The presence of both lineages on the north slope may imply that lake trout have some ability to move around, but could also be an artifact from the numerous recolonizations. One north slope lake had a unique haplotype that should be investigated further as a possible refugia.