• Vertebrate ichnology and paleoenvironmental associations of Alaska's largest dinosaur track site in the cretaceous Cantwell Formation (Maastrichtian) of Denali National Park and Preserve

      Stewart, Dustin G.; Druckenmiller, Patrick; Fowell, Sarah; McCarthy, Paul (2020-10)
      The Upper Cretaceous Cantwell Formation in Denali National Park and Preserve (DENA) has recently been recognized as a major high latitude dinosaur track-bearing unit in Alaska. The abundant trace fossil record of the Cantwell Formation, which represents a diverse community of avian and non-avian dinosaurs, compliments the body fossil record of the state's other major dinosaur-producing unit, the Prince Creek Formation of northern Alaska. However, research in the Cantwell Formation is still in its infancy due to its wide aerial extent and remoteness, and many questions remain concerning the temporal, ichnological, and paleoenvironmental relationships of the formation. Here I describe and analyze the largest known single track site currently known in DENA and all of Alaska -- a football field-sized outcrop named the Coliseum. This site is composed of 65+ meters of vertical section, with laterally extensive fine- to medium-grained sandstone, indurated mudstone, fissile shale, and bentonite. Trace fossils at the Coliseum include true tracks, undertracks, natural casts, and trackways that vary in their preservation from eroded, trampled surfaces to individual prints with skin impressions. The tracks were documented via handheld and UAV-assisted photogrammetry, enabling a large-scale 3-dimensional mapping of the Coliseum. Facies analysis of the site reveal the tracks were formed on crevasse splay and overbank deposits within a fluvial floodplain. U-Pb dating of zircons collected from a bentonite horizon return an age of 69.3±0.9 Ma (early Maastrichtian), improving the temporal constraints of the formation and revealing one of the youngest ages of deposition for the formation. Several new dinosaurian ichnotaxa previously unrecognized from the formation are described, revealing the presence of large-bodied ornithopods, ceratopsids, and non-avian and avian theropod trackmakers. The Coliseum provides a snapshot of an ancient forested environment inhabited by a diverse dinosaurian community deposited in the Late Cretaceous paleo-Arctic.
    • Vetting model and satellite-based estimates of regional scale carbon exchange at northern high latitudes using solar-viewing infrared spectroscopy

      Jacobs, Nicole; Simpson, William R.; Euskirchen, Eugénie S.; Guerard, Jennifer; Maxwell, David A. (2021-08)
      Carbon exchange in the Boreal Forest and its response to a warming climate is a critical process that needs to be understood for more accurate predictions of climate change. Therefore, we established a ground-based long-term monitoring site at the University of Alaska Fairbanks in Fairbanks, Alaska, USA (64.859°N, 147.850°W) operating a solar-viewing Bruker EM27/SUN Fourier transform infrared spectrometer (FTS). This instrument measures vertically integrated column abundances of carbon dioxide (CO₂), methane (CH₄), and carbon monoxide (CO), termed Xgas, i.e., XCO₂. These measurements are directly comparable to satellite-based measurements, for which these ground-based observations provide validation data. Measurements of XCO₂ and XCH₄ have to be extremely precise because variability in atmospheric columns of CO₂ and CH₄ is often less than 1% of the background levels of these long-lived gases. Therefore, the observations in Fairbanks were carefully vetted through comparisons of results from two retrieval algorithms applied to the same observed spectra, comparisons of observations from two EM27/SUN FTS operating side-byside, and comparisons between an EM27/SUN FTS and measurements from a Bruker IFS125HR in the Total Carbon Column Observing Network (TCCON) at Caltech, Pasadena, California. These data are all collected over a period of about 4.5 years. Comparisons of retrieval methods indicate that the results are tightly correlated, but there are offsets that could be corrected with an appropriate scaling factor. Observed biases between two colocated EM27/SUN FTS were in agreement within instrument precision. Biases between the EM27/SUN and TCCON retrievals at Caltech are larger and more variable than biases between the two EM27/SUN FTS in Fairbanks, which may be partially explained by differences in spectral resolution. These biases are also similar to those reported in previous studies. Vetted Fairbanks observations are used in combination with those from two TCCON sites in the Boreal Forest, East Trout Lake, Saskatchewan, Canada (54.354°N, 104.987°W) and Sodankylä, Finland (67.367°N, 26.631°E), to evaluate quality control methods and bias in XCO₂ from the NASA Orbiting Carbon Observatory 2 (OCO-2). This study yielded alternative quality control thresholds and bias correction, tailored to Boreal Forest regions that allow for increased data throughput and reduced seasonality in bias over northern high latitude regions. In particular, increased data throughput in spring and autumn months made it possible to measure XCO₂ seasonal cycles using satellite-based measurements. In this analysis, we found that the Asian Boreal Forest region stood out as having the largest seasonal amplitude and earliest seasonal drawdown of any region. There is also a pronounced west-to-east gradient of increasing seasonal amplitude and earlier seasonal drawdown across the Eurasian continent. Comparisons with two independent global CO₂ models are good, showing high correlation and spatial agreement. Analysis of modeled (GEOS-Chem) surface contact tracer contributions reveals that the largest seasonal amplitudes occur in regions that have the largest contributions from land-based surface contact tracers with 15 or 30 day atmospheric lifetimes, suggesting that accumulations of CO₂ exchanges during atmospheric transport on approximately monthly timescales play an important role in shaping observed XCO₂ seasonal cycles in northern high latitude regions. Furthermore, surface contact tracer contributions from land were more correlated with XCO₂ seasonal amplitude than estimates of total annual fluxes or seasonal amplitudes of flux estimates within a region, emphasizing the importance of understanding the effects of atmospheric transport when interpreting observations of XCO₂.
    • The visual language of Turkish roman dance

      Carter, Bethan J.; Shoaps, Robin; Plattet, Patrick; Yamin-Pasternak, Sveta (2021-08)
      Utilizing Peircean semiotics and Dell Hymes' Ethnography of Communication, this research analyzes the dance style known as Roman havasi or, Turkish Roman dance. Elements and influences under consideration include costuming, dance vocabulary, musical instruments and traditions, gender-based stylistic differences, spheres of performance, audience member and participant demographics, and notions of authenticity in embodiment and presentation. An abridged history of the Roman is also presented, including public policies that influence the rights and lifestyle of Turkish Roman, as such factors have influenced their sense of social belonging as well as their dance and musical expressions. Romani people have experienced marginalization wherever they have immigrated, and scholarship regarding them has not always been beneficial. This thesis aims to increase the visibility, recognition, and appreciation of their culture. Research data was collected via participant observation as a Turkish Roman dance student and performer in Anchorage, Alaska, and from structured interviews with instructors and performers. Video footage was also gathered for analysis and was obtained by the author or via public domain websites. This thesis is accompanied by a collection of video clips featuring various elements of Turkish Roman dance referenced herein, and is available as supplemental material.
    • Western Gwich'in classificatory verbs

      Bushey, Scott T.; Tuttle, Siri; Peter, Hishinlai'; Vajda, Edward (2021-05)
      One of the many challenges faced by learners and teachers of Gwich'in, an endangered Athabascan or Dene language of Alaska and Canada, is a lack of instructional material for classificatory verbs. These verbs classify states and actions, such as lie, carry, and fall, by perceived qualities, such as cloth-like and stick-like, that indicate how and with which nominal entities the state or action takes place. For students of Gwich'in and other Dene languages, such as Navajo and Koyukon, classificatory verbs are an important grammar objective when included in the curriculum. Recognition and production of classificatory verbs is a main objective for students in the second year of the UAF Gwich'in class. Classificatory verb words are also present in vocabulary learned from the first year, such as gishreiin'ąįį "it's sunny" and OBJ naltsuu "I'm wearing OBJ [upper-body garment]". In this thesis I present a documentary, descriptive study of classificatory verbs and their qualities in modern spoken Gwich'in. The first goal of the study is to document examples of Gwich'in classificatory verbs in conversational and narrative discourse, and the second is to describe their morphosemantic properties and behavior. The third goal is to accomplish these documentary and descriptive aims in a way that can be adapted readily to the needs of not only linguists, but also Gwich'in language learners and teachers. Informed by previous documentary and descriptive work on classificatory verbs in other Dene languages, I attempt to provide a similarly useful text for Gwich'in, reconciling several competing nomenclatures and illustrating the relationship between classificatory verb theme sets, such as "carry", and semantic classes of verb stems, such as "animate", in a broad range of modal and aspectual contexts. Although this thesis is intended primarily as a reference work for learners and teachers, it also provides a resource for linguists comparing Gwich'in classificatory verbs with those in related Dene languages. The classificatory verb data in this thesis is drawn from a body of Gwich'in class notes and assignments, well as transcribed Gwich'in oral literature and consultation with a native speaker of the language. Classroom instruction took place between 2018 and 2020 at the University of Alaska Fairbanks and emphasized spoken language production with communicative aims. In addition to work from the Gwich'in language classroom, limited native speaker consultation regarding classificatory verbs was also conducted in February 2020. The third data source for this study is the rich body of narrative discourse available in the form of transcribed oral literature. These works record Gwich'in traditional narrative knowledge, lore, and history across a broad range of topics, in which classificatory verbs may be readily encountered and examined. Having drawn from these three pools of data, this thesis describes the morphosemantic qualities of Gwich'in classificatory verbs while considering the available data on other Dene languages and considers actual and potential application of this data in the language classroom.
    • Widespread capacity for denitrification in soils, streams, and thermokarst lakes of boreal Alaska

      Burnett, Melanie S.; Harms, Tamara K.; Ruess, Roger W.; Walter Anthony, Katey M. (2021-05)
      Rapid warming in Alaska is causing permafrost to thaw, especially in the region of discontinuous permafrost, where soil temperatures may only be a few degrees below 0 °C. An intensifying fire regime may also be exacerbating permafrost thaw with more frequent and severe fires removing insulating organic layers above permafrost. Permafrost thaw releases carbon and nitrogen (N) into the actively cycling pools, and whereas carbon emissions following permafrost thaw are well documented, the fates of N remain unclear. Denitrification and release of nitrous oxide (N₂O) or nitrogen gas (N₂) could result in N loss from ecosystems, but the contributions of these processes to the high-latitude N cycle remain uncertain. I quantified microbial capacity for denitrification and nitrous oxide production in boreal soils, lakes, and streams, and assessed correlates of denitrifying enzyme activity in interior Alaska to determine if denitrification could contribute significantly to N loss from the boreal forest. Across all landscape positions, median potential denitrification rate under anoxic conditions with nitrate and organic carbon amendment was 4.15 [mu]g N₂O-N /kg dry soil*h (range -6.39 to 479.94). Denitrification potential was highest within and along streams in both sediments and adjacent riparian soils, upland soils were intermediate, and lakes supported lower rates, whereas deep permafrost soils supported little denitrification. Time since last burn had no effect on denitrification potential in upland soils. Across all landscape positions, denitrification potential was negatively correlated with ammonium pools. In lakes, potential rate of denitrification declined with sediment depth, and was positively driven by organic matter content. In this era of anthropogenic climate change, pervasive N loss to denitrification in the boreal forest could constrain the capacity for N-limited primary producers to preserve carbon stocks in soils following permafrost thaw.
    • The Yup'ik relationships of qiluliuryaraq (processing intestine)

      Carrlee, Ellen; Schweitzer, Peter; Koester, David; Lee, Molly; Hill, Erica; Plattet, Patrick (2020-12)
      This project explores multiple Native cultural contexts that intersect in the use and understanding of intestine. Gut (tissues of internal organs including stomach, intestine, bladder and esophagus) as a raw material was historically used by many circumpolar cultures to make items like drums, raincoats, hats, windows, sails, containers, and hunting floats. These items are abundant in museum collections, but rarely seen today in cultural practice or the art market. Intestine is a natural material that was replaced by synthetic materials, but its dual physical properties of protection and permeability are the only features replicated by plastics. Examination of intestine as an obsolete material reveals both changes and resilience in different kinds of relationships. Emphasizing the meaning and materiality of gut over analysis of artifacts made from it emphasizes interactions among human, animal, and spiritual beings over formalistic approaches privileging object interpretations. Preferential investigation of a raw material over finished artifacts focuses the study on actions and values in Native places. Fieldwork components for this study include documentation of indigenous gut processing, sewing and repair workshops in museum contexts, processing fresh intestine in the Yup'ik village of Scammon Bay, and discussion of gut with Yup'ik cultural experts. The theoretical approach uses Actor-Network Theory (ANT) as a foundation, animated with practice theory and relational ontology. Since ANT creates space for human, animal, and object agency, reciprocal relationships among these actors will be explored through frameworks of materiality, object biography, gender studies, animal personhood, and the gift. This endeavor may promote a new model for the use of material culture to illuminate Native values. In the case of intestine, its decline in use connects to changes in technology and spirituality while resilience and revitalization of gut technology promotes identity and demonstrates traditional values.
    • Zooplankton community composition in relation to environment and juvenile salmon diets in Icy Strait, Southeast Alaska

      Fergusson, Emily A.; Eckert, Ginny; McPhee, Megan; Heintz, Ron (2020-12)
      Zooplankton in the nearshore marine habitat function as an important prey resource for many pelagic fishes, are a major component of the lower tropic level, and serve as a vital ecosystem indicator. Understanding how the zooplankton community changes in response to fluctuations in biophysical factors is critical in a changing climate and is important to understanding the dynamics of commercially important upper-trophic level species that depend nutritionally on zooplankton. The Alaska Fisheries Science Center's Southeast Coastal Monitoring project has surveyed the pelagic ecosystem in eastern Icy Strait monthly from May to August since 1997 to understand how environmental variation affects the pelagic food web and the sustainability of salmon resources. I used this long-term dataset (1997-2017) to address the goals of this study: 1) to investigate the influence of temperature on the Icy Strait zooplankton community; and 2) to understand how juvenile salmon utilize zooplankton prey in relation to temperature driven fluctuations in the zooplankton community. In Chapter 1, I noted that the composition of the zooplankton community varied in years with anomalously high or low temperatures. I observed shifts in the timing of development in many key taxa during these anomalous years. For example, in anomalously cool years, several taxa were found in higher densities later in the summer than in anomalously warm years. In Chapter 2, I examined how oceanographic factors influenced the diet composition and quality of four species of juvenile Pacific salmon (Oncorhynchus spp.) in Icy Strait (Southeast Alaska) from 2013 to 2017. In 2015 I observed a change in diets, including zooplanktivorous (pink salmon O. gorbuscha, chum salmon O. keta, and sockeye salmon O. nerka) and piscivorous (coho salmon O. kisutch) species, from typically diverse diets to diets dominated by euphausiids. This year was notable for warm waters, deep pycnoclines, and below average zooplankton nutritional quality. Juvenile salmon appeared to supplement their lipid intake and meet nutritional requirements by switching to larger euphausiid prey. The results from these studies increase our understanding of zooplankton community dynamics, salmon trophic relationships, and the resilience and flexibility of the food web during climate-driven reorganizations of the pelagic marine ecosystem.