• Post stroke interpersonal communication: an intimate exploration of stroke survivors' lived experiences

      Hendley, Lora L.; Richey, Jean; Taylor, Karen; Jarrett, Brian (2015-12)
      This qualitative study explores the personal and intimate lived experiences of stroke survivors who suffer the comorbid emotional sequelae of Post Stroke Depression (PSD) and how it affects their rehabilitation and interpersonal relationships post stroke. By using Uncertainty Reduction Theory (URT), the idea of Social Construction of Identity, the epistemology of Narrative Inquiry (NI), and conversational interviews (CI), with stroke survivors, their spouses/significant others, friends, and other family members, the aim of this body of research has been to take on the difficult task of observing how stroke survivors navigate the difficult and sometimes daunting path that all stroke survivors must travel as they attempt the reconstruction of their self post stroke. They face every new day with the knowledge of who they once were and who they are now. The person that they are now has become their reality. Many stroke survivors regardless of the hemisphere in which the brain lesion occurs, suffer from some degree of the post stroke emotional sequelae, or a condition following and resulting from a disease, of post stroke depression (PSD). With the comorbid occurrence of PSD comes yet another challenge to their reconstruction process. The findings of this research study have remained consistent with the current research data and literature on stroke, stroke recovery, PSD, and aphasia.
    • Post-caldera eruptions at Okmok Volcano, Umnak Island, Alaska, with emphasis on recent eruptions from cone A

      Grey, Delenora M. (2003-12)
      Okmok volcano has undergone two caldera-forming eruptions, 12,000 and 2050 BP, and has been quite active in historic time. The historic eruptive record has been compiled and augmented with descriptions and photographs of recent eruptions. Eruptions in 1958 and 1997 produced the first post-caldera lava flows to traverse most of the caldera floor. The source of these flows, Cone A, has been constructed largely during the 20th century. Major element analysis of lavas from eight major intracaldera cones reveals two chemically and spatially separate trends, which suggest two separate magma sources beneath the caldera, one feeding an arc of cones extending from the west to north margin of the caldera, the other feeding an arc running from southwest to east. Recent geodetic results by other workers show a single active inflation source related to Cone A but located beneath the center of the caldera. A rheologic study of the 1997 lava flow was undertaken to determine how viscosities calculated from flow morphology compare with viscosities and eruption temperatures obtained from petrology. This may be a useful tool for constraining composition of new flows observed by satellite imagery, and for constraining eruptive conditions for older flows when chemistry is known.
    • Post-fire variability in Siberian alder in Interior Alaska: distribution patterns, nitrogen fixation rates, and ecosystem consequences

      Houseman, Brian Richard; Ruess, Roger; Hollingsworth, Teresa; Verbyla, Dave (2017-12)
      The circumpolar boreal forest is responsible for a considerable proportion of global carbon sequestration and is an ecosystem with limited nitrogen (N) pools. Boreal forest fires are predicted to increase in severity, size, and frequency resulting in increased losses of N from this system due to volatilization. Siberian alder (Alnus viridis ssp. fruticosa) N-fixation is a significant source of N-input within the interior Alaskan boreal forest and likely plays a pivotal, though poorly understood, role in offsetting losses of N due to fire. This study disentangles the effects of fire severity, post-fire age, and environmental variables on Siberian alder N-input across the upland boreal forest and quantifies the landscape-level implications of Siberian alder N-input on N pool balance. Stand types of an early- and intermediate-age burn scar were determined by relevé plot sampling, hierarchical clustering, and indicator species analysis. Alder growth traits (density, nodule biomass, nodule N-fixation, and other traits) were sampled across all stand types, burn scars, and a fire severity gradient. Pre- and post-fire landscape-level N-fixation inputs were quantified within the early-age burn scar by scaling-up Siberian alder growth traits to the stand-level and then mapping the total area of pre- and post-fire stand types. Results show that fire severity shares a complex relationship with Siberian alder N-input in black spruce stands, wherein moderate fire severity has a negligible effect on Siberian alder N-input, moderate to high fire severity increases Siberian alder N-input, and high fire severity reduces Siberian alder N-input. Fire likely limited alder vegetative propagation in post-fire black spruce trajectory stands but enhanced propagation in post-fire deciduous trajectory stands that experienced moderate severity. Following the 2004 Boundary Fire, Siberian alder N-input showed an overall increase across the landscape, mostly within post-fire deciduous stand types. Future increases of fire severity and subsequent conversions of stand type from black spruce to deciduous dominance have the potential to increase total short-term N-input on the landscape, but a majority of those gains will be concentrated within a small proportion of the post-fire landscape (i.e. deciduous trajectory stand types). In the boreal forest, the temporal and spatial pattern of ecosystem processes that rely on N fixation inputs is dependent on the recruitment and growth of Siberian alder, which is in turn dependent on a complex relationship between fire severity, stand type, and post-fire age.
    • Post-Upgrade Thesis Test 10/21/17

      CHISUM (2017-10)
      Post-Upgrade Thesis Test 10/21/17
    • Postbreeding Ecology Of Shorebirds On The Arctic Coastal Plain Of Alaska

      Taylor, Audrey R.; Powell, Abby N.; Lanctot, R. B.; Huettmann, F.; Kitaysky, A. S.; Williams, T. D. (2011)
      Previous research on the Arctic Coastal Plain (ACP) of Alaska has shown that postbreeding shorebirds congregate at coastal sites prior to fall migration. Relatively little has been done to compare distribution, community characteristics, or behavior broadly across the ACP landscape, but this information is necessary to set the context for interpreting population demographics and setting conservation priorities. I collected data on distribution, species composition, phenology, and habitat use of postbreeding shorebirds in 2005--2007. I found that distribution of shorebirds across the ACP was not uniform: I identified persistent "hotspots" at Peard Bay, Pt. Barrow/Elson Lagoon, Cape Simpson, Smith Bay to Cape Halkett, and at the Sagavanirktok and Kongakut Deltas. Staging phenology varied by species and location, and differed than that reported in previous studies for several species. Three foraging habitat guilds existed with birds favoring gravel beach, mudflat, or salt marsh/pond edge habitats. Using VHF telemetry. I examined how shorebirds moved from tundra breeding sites to and between coastal postbreeding sites. I found that most species exhibited a variable direction of movement compared to their ultimate migration direction; this may be related to each species' overall length of stay on the ACP. I also found species-specific patterns of movements and residence time that were indicative of differing life history strategies. Lastly, I examined the use of physiological tools (triglyceride and corticosterone levels) to assess function and quality of foraging sites for postbreeding shorebirds, taking into account varying molt strategies. I determined that molt strategies affected physiological profiles and physiologic metrics varied through space and time. However, my hypotheses for variation in physiological patterns for shorebirds employing different molt strategies and using sites of varying quality were not completely upheld. I suggest that assessments of site quality for postbreeding shorebirds should consider species-specific life history strategies, and use multiple species and physiological metrics as indicators. Given suspected declines in North American shorebird populations, and accelerated rates of environmental change in northern Alaska, this contextual information regarding postbreeding distribution, population characteristics, behavior, and physiology may help interpret changes in shorebird populations or behavior and establish strategies to protect important habitat.
    • Postwar reconciliation: parental attitudes towards Sri Lanka's trilingual education policy

      Malalasekera, Nimasha S.; Marlow, Patrick; Siekmann, Sabine; Martelle, Wendy (2019-08)
      After 26 years, the ethnic-based civil war in Sri Lanka ended in 2009. The Trilingual Education Policy seeks to reconcile the estranged Sinhalese and Tamil communities by teaching each community the other's language in this postwar context. Scholars argue that national reconciliation through Trilingual Education is unlikely to succeed because of the continued mistrust and prejudice between the two communities and the demand for English as key to social mobility and economic prosperity. Since these claims are not supported by empirical evidence, this study seeks to find empirical data to support or counter these claims. The study investigates parental attitudes to their second languages, Sinhala, Tamil, and English, the three languages of the Trilingual Education Policy to understand its likely success. Twenty-one parents whose children receive Sinhala, Tamil, and English L2 tuition in Colombo 5 were selected through convenience sampling. The study uses the constructivist grounded theory, mentalist approach to language attitudes, and concepts of capital and linguicism for data analysis. The study found that Sinhala has capital for the Tamils and is valued and glorified by them, whereas Tamil has no capital for the Sinhalese and is devalued and stigmatized by them. Both groups valorize and glorify English, for it has more capital than Sinhala/Tamil both locally and translocally. Concluding that the Trilingual Education Policy is unlikely to succeed because of linguicism, the study recommends providing incentives for learning Sinhala and Tamil and advocating dual language education for reconciling the two communities.
    • post~conscious

      Moser, Nicklaus O.; Hill, Sean; Cooper, Burns; Farmer, Daryl; Hirsch, Alex (2017-05)
      post~conscious is a collection of poems that attempts to explore the potential of what may be described as a fractal rhetoric. As anyone can know or find out, the term fractal does not only describe pretty, self-similar shapes, like snowflakes, but at its mathematical core describes a set of values which are derived from convoluting and reiterating an algorithm, so that if A2+B=A and A=0 and B=1, then A=1. At this point one simply drops the new value for A (1) back into the equation and solves for yet another, new value for A (2). Of course, in reality, B is not a real number, but an imaginary one, such as 1i, so that every iteration of A is confined to a complex number plane and will, as, for instance, in the case of the very well-known Mandelbrot Set, never exceed 2. But, of course, there is an infinite number of numbers between 1 and 2. However, the importance of fractal geometry for post~conscious is not that the fractal provides a formula for understanding human thought (though it may) or for creating poetry. The importance rests in the more symbolic, parallel induction that utterances which are limited to an imaginary plane or environment or subject, may, after numerous iterations, begin to cohere into a thing that resembles the imagination proper. Of course, one has no image for the imagination other than every image. This paradox is post~conscious' raison d'être. As has been stated, yet not explained, post~conscious attempts to make use of a fractal rhetoric. Yet because a rhetoric does not rely upon somatic phenomena, such as images, sounds, or touches, to exist, but may exist in a purely semiotic form/nonform, yet can be simulated structurally with language, yet not with just any aspect of language, but predominantly with syntactical cleverness, post~conscious may attempt to delineate the form of the fractal rhetoric which may be supposed to resemble the imagination proper, if such a nonity can be said to exist anywhere, or at any time, outside of itself. Thus, post~conscious:
    • Potential muskox habitat in the National Petroleum Reserve-Alaska: a GIS analysis

      Danks, Fiona Susan (2000-08)
      Muskoxen (Ovibos moschatus), reestablished in northern Alaska in recent decades, have been increasing in number and distribution. However, their selection of habitat within the landscape, historically and presently, remains inadequately documented. This project produced maps of predicted muskox habitat in the National Petroleum Reserve-Alaska (NPR-A), that provide a basis for management of muskoxen and protection of their habitat in relation to proposed oil, gas and mineral exploration. Vegetation analyses showed compositional differences and interactions between vegetation and terrain. Within a geographical information systems (GIS) database, muskox locations, satellite-based vegetation maps and terrain data for the Kuparuk River drainage basin were assimilated, and a maximum likelihood classification developed to produce a habitat selection model incorporating the interactive effects of these characteristics. Using NPR-A GIS data, the model was extrapolated to produce maps showing suitable summer habitat in lower-lying drainages and wetter areas, and suitable winter habitat in drier, more rugged, exposed areas.
    • The potential of lodgepole pine in Alaska

      Cushing, Alina (2005-08)
      The introduction of non-native trees should be informed by various perspectives. In the case of forestry in high-latitude regions, managers face the challenge of finding cold-hardy species adequately adapted to harsh climatic environments; Lodgepole pine (Pinus contorta Dougl. Ex. Loud.) has been introduced to three regions at or above its natural northern latitudinal extent; Alaska, Iceland, and northern Sweden. Analysis of interviews in each region revealed the structure of common arguments, including underlying assumptions and perceptions of the natural world. Results of a mail-out-survey to the Alaskan public indicate that a considerable portion of the public is concerned about the possibility for adverse ecological effects on the native ecosystem. However, acceptance of non-native trees increased under certain circumstances; e.g. small-scale ornamental plantings, and when economic benefit is demonstrated. In comparisons of twenty-year growth data of lodgepole pine in Alaska with native white spruce (Picea glauca), lodgepole pine achieved greater height, diameter, and volume. The response of lodgepole pine in all three regions to scenarios of climate change was predicted using tree-ring analysis. Results indicate a negative response (reduced growth) in the Fairbanks area, a positive response (increased growth) in Delta and Glennallen, and a positive response at all but one Icelandic site and both Swedish sites. Overall, lodgepole pine appears relatively well-adapted to the present and modeled future environments of interior Alaska, Iceland, and northern Sweden.
    • Potential of Pleurotus ostreatus to remediate diesel-contaminated soil in subarctic mesocosms

      Anderson, Christin Elizabeth; Leigh, Mary Beth; Juday, Glenn; Valentine, David (2016-08)
      Pleurotus ostreatus, a gilled basidiomycete, has previously been shown to biodegrade petroleum using extracellular enzymes. However, few studies have tested petroleum biodegradation by fungi, known as mycoremediation, in cold temperatures. I conducted mesocosm studies to assess the potential from mycoremediation of diesel-contaminated soil collected from interior Alaska with a cultivated strain of P. ostreatus var. columbinus at 4 ºC, 10 ºC, and 25 ºC. In soil, both uninoculated and inoculated with P. columbinus, diesel range organics (DRO) decreased by 22-28% (p=0.455), 41-55% (p=0.236), and 91-92% (p=0.735) at the three temperatures, respectively. The differences in DRO loss between uninoculated and inoculated mesocosms at each temperature were not statistically significant, most likely due to high soil heterogeneity. However, DRO loss was greater as temperature increased, and was significantly different between the temperatures evaluated. These results indicate that temperature is a more important factor controlling DRO loss than substrate or inoculation with P. columbinus. Inoculation may enhance DRO loss at medium temperatures, but inoculation does not appear to enhance DRO loss at the highest and lowest temperatures in this study. The results also suggest that manipulating the temperature of remediation sites may be more important than inoculating with Pleurotus, and that inoculation might not be needed at sites where temperature can be increased.
    • Potential recharge estimates of Arctic lakes to aid water management on the North Slope of Alaska

      Cormack, Chad Michael (2011-08)
      Water is a valuable asset to the petroleum industry on the North Slope of Alaska. Current water-permitting processes do not take into account watershed principles in the allocation of water resources. This has primarily been due to lack of information related to tundra lake watersheds and associated water use. This thesis evaluated several study lakes located within the eastern portion of the National Petroleum Reserve Alaska (NPRA) to demonstrate how watershed and meteorological parameters could be incorporated into water-use management practices. Watershed areas were delineated for the study lakes digitally with geographic information systems (GIS) and Rivertools software. Estimates for rainfall, snow-water equivalent, and evapotranspiration were combined to calculate potential recharge estimates for each individual study lake. A potential recharge tool was developed to help calculate potential recharge values. This tool can be a good first step for industry to begin to apply watershed principles into the water-permitting processes. For the study lakes analyzed, it was concluded that water withdrawal would not adversely affect the sustainability of the water bodies. With the current level of available data, recharge estimates are accurate enough to be used in permitting processes. It is recommended that geographic lake parameters (i.e., watershed and lake areas) and meteorological parameters (e.g., rain, snow, evapotranspiration) are further studied and included in future lake permits.
    • The practical application of a hydraulic power recovery turbine at the Valdez Marine Terminal

      Bruns, Brendon; Dandekar, Abhijit; Heimke, David; Wies, Richard (2019-05)
      A hydraulic power recovery turbine (HPRT) is a machine designed to capture energy from the pressure differential of a fluid. The HPRT recovers energy that would otherwise be lost to entropy in flowing fluid processes. When the shaft of the HPRT is coupled to an electric generator, the electricity produced can be employed for practical purposes. At the terminus of the Trans-Alaska Pipeline System (TAPS) in Valdez, favorable hydraulic conditions and electrical infrastructure exists for the application of an HPRT to generate significant power. This project will study the practical application of an HPRT as a source of clean, reliable electricity to the VMT. Installation of an HPRT has the potential to reduce diesel consumption and emissions of air pollutants at the VMT.
    • Praxis and insider-outsider relationships: the role of non-indigenous teachers in promoting indigenous language and culture in educational spaces

      Kealy, Kelly; Marlow, Patrick; Siekmann, Sabine; Webster, Joan Parker (2014-12)
      In many places throughout Alaska, non-Alaska Native certified teachers are working in communities that foster (or seek to foster) Alaska Native language and culture revitalization in the schools. Often, this means teachers with limited knowledge of the target language need to figure out how to support that content in their classrooms. This qualitative thesis examines interview and field note data collected from five non-Alaska Native teachers (working in Southwest schools) while they took summer classes at an Alaskan university. The teachers shared reflections on their struggles and successes in seeking to facilitate the integration of local Indigenous Knowledges into their schools and classrooms. Several common themes were identified, including Positioning Self as Co-Learner, Transforming Attitude towards Village English (VE)/Yugtun, Promoting VE/Yugtun in the Classroom, and Valuing Linguistic Affordances to Transform Self. When viewed through the lens of critical pedagogy, these themes indicate that participants are engaging in praxis -- or reflecting critically and acting -- in order to move towards supporting Indigenous knowledges in beneficial, non-appropriative ways.
    • Pre-stress loss due to creep in precast concrete decked bulb-tee girders under cold climate conditions

      Vandermeer, Drew E.; Ahn, Il-Sang; Liu, Juanyu (2019-05)
      This report presents guidelines for estimating pre-stress loss in high-strength precast pretensioned concrete Decked Bulb-Tee (DBT) bridge girders in cold climate regions. The guidelines incorporate procedures yielding more accurate predictions of shrinkage and concrete creep than current 2017 American Association of State Highway and Transportation Officials (AASHTO) specifications. The results of this report will be of particular interest to researchers and cold climate bridge design engineers in improved predictions of design life and durability. The use of high-strength concrete in pre-tensioned bridge girders has increased in popularity among many state highway agencies. This fact is due to its many beneficial economic and constructability aspects. The overall cost of longer girders with increased girder spacing in a bridge that is precast with high strength concrete can be significantly reduced through the proper estimating factors. Recent research indicates that the current provisions used for calculating prestress losses in cold regions for high-strength concrete bridge girders may not provide reliable estimates. Therefore, additional research is needed to evaluate the applicability of the current provisions for estimating pre-stress losses in high-strength concrete DBT girders. Accurate estimations of pre-stress losses in design of pre-tensioned concrete girders are affected by factors such as mix design, curing, concrete strength, and service exposure conditions. The development of improved guidelines for better estimating these losses assists bridge design engineers for such girders and provide a sense of security in terms of safety and longevity. The research includes field measurements of an environmentally exposed apparatus set up to measure shrinkage, creep and strain in cylinders loaded under constant pressure for a full calendar year.
    • Precipitation in the Alaska central Arctic

      Homan, Joel W.; Kane, Douglas; Hinzman, Larry; Sturm, Matthew; Toniolo, Horacio (2015-12)
      Environmental change currently stimulates much of the interest in high-latitude hydrologic studies, as northern areas are expected to be strongly impacted by warming. This thesis consists of a comprehensive assessment of solid and liquid precipitation throughout the Alaska Central Arctic. The founding hypothesis are: (1) the spatial distribution of snow and warm season precipitation are linearly related to elevation, (2) annual precipitation inputs are dominated by warm season precipitation when potential moisture sources are ice free, and (3) moisture responsible for snow-producing storms is primarily advected through atmospheric circulation. To verify the validity of the hypothesis, the temporal variability and spatial distribution of snow and warm season precipitation were extensively measured. Snowpack patterns were established using over 1000 snow surveys from end-of-winter field campaigns. The snowpack distribution patterns were similar from year to year and relatively independent of elevation, with roughly an average of 100 mm of snow water equivalent (SWE) from the Arctic Coast to the Brooks Range divide. For the same 1500 m change in elevation, warm season precipitation has a large orographic change, which increases more than 240 mm. Warm season precipitation was evaluated using 31 meteorological stations and although a strong spatial distribution was found, no discernible long-term trends were identified in the somewhat limited 29 year data set. The accumulation of end-of-winter SWE and warm season precipitation measurements were combined to evaluate the distribution of annual precipitation. Annual precipitation varies temporally and spatially over the Alaska Central Arctic. At high elevations, 70% of the annual precipitation is liquid, while at low elevations, liquid precipitation only represents 40% of the annual budget and end-of winter SWE becomes the dominate precipitation contributor. Moisture responsible for snow-producing storms was found to originate from different sources depending on the time of year and ice cover conditions. North originating moisture is three times more likely to occur during the fall when sea ice is thin, or nonexistent. Mid-winter moisture was found to advect into the Arctic from the south. The timing and travel pathways of snowfall events were determined using an atmospheric model (HYSPLIT) and supplemental surface analysis charts.
    • Predator-prey dynamics between mountain lions and mule deer: Effects on distribution, population regulation, habitat selection, and prey selection

      Pierce, Becky Miranda; Bowyer, R. T.; Bleich, V. C. (1999)
      Mountain lions (Puma concolor) and mule deer ( Odocoileus hemionus), which share a winter range in the Eastern Sierra Nevada in Round Valley, California, USA, were fitted with radio-telemetry collars and tracked to determine their movements and cause of mortality. The mountain lion population of Round Valley refers to a group of individuals that lived in close proximity to one another, essentially isolated from similar groups during the winter, and fed on the migratory herd of mule deer that overwinter in Round Valley. Mountain lions migrated seasonally with the deer population, and two distinct patterns for coping with variability in abundance of prey were observed. The unique migratory behavior identified for the mountain lions in this study indicates a more flexible social system for mountain lions than previously described. Tests of whether the presence of another mountain lion affected where individuals to killed deer indicated that social interactions had no effect and that social behavior was not regulating the population of mountain lions via spatial partitioning of prey. Examination of habitat selection by mule deer and mountain lions revealed that mule deer selected habitat at higher elevations (P < 0.001) with more bitterbrush ( Purshia tridentata) and less rabbitbrush (Chrysothamnus nauseosum ) than random locations. Mountain lions killed deer in relatively open areas with more desert peach (Prunus andersonii) than locations in which deer foraged. Those results indicated that deer were not confronted with a tradeoff in terms of habitat selection on the winter range because habitat with the best forage (e.g. bitterbrush), also provided the least predation risk. Comparisons of mule deer killed by mountain lions, coyotes, and automobiles indicated that mountain lions selected young (<1 year old) deer and both predators selected older age classes among adults. Furthermore, there was no selection by either predator for animals in poor condition. Among mountain lions in different social categories, female mountain lions with kittens selected more young deer than did other social categories. This study indicated that ambush predators (mountain lions) may be as selective for prey as coursing predators (coyotes) and that lactation in mountain lions may play a role in determining prey selection. ion.
    • Predatory Hymenopteran assemblages in boreal Alaska: associations with forest composition and post-fire succession

      Wenninger, Alexandria; Wagner, Diane; Hollingsworth, Teresa; Skies, Derek (2018-05)
      Predatory Hymenoptera play key roles in terrestrial foodwebs and affect ecosystem processes, but their assemblage composition and distribution among forest habitats are poorly understood. Historically, the boreal forest of interior Alaska has been characterized by a fire disturbance regime that maintains vegetation composition dominated by black spruce forest. Climate-driven changes in the boreal fire regime have begun to increase the occurrence of hardwood species in the boreal forest, including trembling aspen and Alaska paper birch. Replacement of black spruce forests with aspen forests may influence predatory hymenopteran assemblages due to differences in prey availability and extrafloral nectar provisioning. Furthermore, changes in the frequency and extent of boreal forest fires increase the proportion of forests in earlier successional stages, altering habitat structure. The primary goal of this study was to characterize predatory hymenopteran assemblages in post-fire boreal forests of interior Alaska. To investigate this, the abundance, species richness, and composition of predatory hymenopteran assemblages were compared among forests at different stages of succession that were dominated by black spruce pre-fire, but that vary in their tree species composition post-fire. Predatory hymenopterans were separated into three groups: ants, macropterous wasps, and micropterous wasps. Ant species richness and abundance were not related to forest composition, but both were significantly higher in early-successional forests than in mid-late successional forests. In contrast, macropterous wasp morphospecies richness and abundance, as well as micropterous wasp abundance, were positively related to the basal area of aspen, suggesting that aspen forests benefit macropterous and micropterous wasps, perhaps due to extrafloral nectar provisioning and the availability of greater quality prey than is provided by black spruce. Wasp assemblages did not differ between successional stages. This study is the first to characterize the influence of post-fire succession on predatory hymenopteran assemblages of the boreal forest at a large spatial scale. The results suggest that continued warming of the boreal forest will have cascading influences on the insect assemblages of boreal Alaska.
    • Predicting contaminant transport pathways in the Caribou-Poker Creek Research Watershed

      Autier, Vincent (2002-12)
      In order to evaluate the impact of natural organic matter (NOM) on drinking water, the hydrology of the Caribou-Poker Creeks Research Watershed (CPCRW) was considered. The CPCRW provided an excellent opportunity to investigate contaminant transport as it relates to hydrology in a well studied, discontinuous permafrost environment. The seasonal variation of organic chemistry of three different water sources (i.e. ground water, artesian spring and stream) was studied during the course of the year 2001. This thesis comprises three chapters, each of which seeks to gain a better understanding of the contaminant transport pathways in a boreal watershed, Caribou Poker Creeks Research Watershed. The hypothesis of Chapter One was that the heavy metal Cadmium (Cd) is strongly correlated to NOM. The objective was to establish the likely sources of cadmium mobility in organic rich soils. Cadmium was selected because of its tendency to be more mobile in soils than other heavy metals. The hypothesis of Chapter Two was as follows; the chemical nature of dissolved organic matter (DOM) changes during the course of a year in a boreal watershed. The objective of this study was to evaluate the seasonal character of DOM in the CPCRW. DOM was characterized using pyrolysis-gas chromatograph/mass spectrometry (Py-GC/MS), as well as ultraviolet absorbance at 254 nanometers (UV254) and dissolved organic carbon (DOC). Finally, Chapter Three had for central hypothesis that water could be traced to its origin through a correlation of NOM fingerprints. NOM was used as a natural tracer. One hypothesis was that the water appearing on the discharge areas (north-facing slopes) was derived from infiltration at higher elevation on recharging area (south-facing slopes). It was also expected to find that surface water in downstream segments could be correlated with an upstream source, and that this relationship would change during the course of the year. The main objective of this thesis was to establish the relationship of NOM type (chemical/physical characteristic) to Cd mobilization.
    • Predicting Distributions of Estuarine Associated Fish and Invertebrates in Southeast Alaska

      Miller, Katharine Bollinger; Norcross, Brenda; Iken, Katrin; Weingartner, Tom; Mundy, Phillip; Huettmann, Falk (2013-05)
      Estuaries in Southeast Alaska provide habitat for juveniles and adults of several commercial fish and invertebrate species; however, because of the area's size and challenging environment, very little is known about the spatial structure and distribution of estuarine species in relation to the biotic and abiotic environment. This study uses advanced machine learning algorithms (random forest and multivariate random forest) and landscape and seascape-scale environmental variables to develop predictive models of species occurrence and community composition within Southeast Alaskanestuaries. Species data were obtained from trawl and seine sampling in 49 estuaries throughout the study area. Environmental data were compiled and extracted from existing spatial datasets. Individual models for species occurrence were validated using independent data from seine surveys in 88 estuaries. Prediction accuracy for individual species models ranged from 94% to 63%, with 76% of the fish species models and 72% of the invertebrate models having a predictive accuracy of 70% or better. The models elucidated complex species-habitat relationships that can be used to identify habitat protection priorities and to guide future research. The multivariate models demonstrated that community composition was strongly related to regional patterns of precipitation and tidal energy, as well as to local abundance of intertidal habitat and vegetation. The models provide insight into how changes in species abundance are influenced by both environmental variation and the co-occurrence of other species. Taxonomic diversity in the region was high (74%) and functional diversity was relatively low (23%). Functional diversity was not linearly correlated to species richness, indicating that the number of species in the estuary was not a good predictor of functional diversity or redundancy. Functional redundancy differed across estuary clusters, suggesting that some estuaries have a greater potential for loss of functional diversity with species removal than others.