• Optical observations of critical ionization velocity chemical releases in the ionosphere: The role of collisions

      Hampton, Donald Loyd (1996)
      In recent years researchers have pointed out the importance of collisional processes in ionospheric chemical releases performed to study Alfven's critical ionization velocity effect (CIV). Ionizing collisions, including charge exchange with ambient O$\sp+$ and associative ionization, can not only help initiate CIV, but can also lead to 'contamination' of the ion cloud. Most of the proposed collisions have associated emissions which should be observable with sensitive detectors, but until now have not been attempted since atomic processes had not been considered important. The first four releases of the CRRES satellite were performed to study CIV. The releases were at local dusk over the south Pacific in September, 1990, and were observed from two aircraft with low light level cameras, both filtered and broadband. Ion inventories of the releases show ionization yields (number of ions per number of available neutrals) of 0.02% for Sr, 0.15% for the first Ba release, 0.27% for Ca and 1.48 for the second Ba release. The release clouds were seen to glow quite strongly, below the terminator. The measured light is found to be primarily from line emissions which indicates that it is due to collisional processes in the release cloud. Two measurements were made on the release cloud data; (1) the absolute intensity of the release clouds and (2) the ratio between a broadband intensified CCD (ICCD) and an imaging photon detector filtered for the Ba$\sp+$ 455.4 nm emission line. The measured ratio is compared to the expected ratio for charge exchange collisions, and to electron impact excitation of Ba. The measured ratio is consistent with emissions being from charge exchange collisions. However, when compared to the total intensity of emissions expected from charge exchange, the absolute intensity in the release cloud measured by the ICCD is five times greater. The two measurements are in conflict, and with this limited set of data cannot be fully resolved. The ratio measurement does indicate that any CIV discharge in the Ba releases was extremely weak, and that charge exchange is the dominant collisional process in Ba releases.
    • Optical Remote Sensing Of Snow On Sea Ice: Ground Measurements, Satellite Data Analysis, And Radiative Transfer Modeling

      Zhou, Xiaobing; Li, Shusun; Stamnes, Knut; Sharpton, Buck; Jeffries, Martin O.; Echelmeyer, Keith (2002)
      The successful launch of the Terra satellite on December 18, 1999 opened a new era of earth observation from space. This thesis is motivated by the need for validation and promotion of the use of snow and sea ice products derived from MODIS, one of the main sensors aboard the Terra and Aqua satellites. Three cruises were made in the Southern Ocean, in the Ross, Amundsen and Bellingshausen seas. Measurements of all-wave albedo, spectral albedo, BRDF, snow surface temperature, snow grain size, and snow stratification etc. were carried out on pack ice floes and landfast ice. In situ measurements were also carried out concurrently with MODIS. The effect of snow physical parameters on the radiative quantities such as all-wave albedo, spectral albedo and bidirectional reflectance are studied using statistical techniques and radiative transfer modeling, including single scattering and multiple scattering. The whole thesis consists of six major parts. The first part (chapter 1) is a review of the present research work on the optical remote sensing of snow. The second part (chapter 2) describes the instrumentation and data-collection of ground measurements of all-wave albedo, spectral albedo and bidirectional reflectance distribution function (BRDF) of snow and sea ice in the visible-near-infrared (VNIR) domain in Western Antarctica. The third part (chapter 3) contains a detailed multivariate correlation and regression analysis of the measured radiative quantities with snow physical parameters such as snow density, surface temperature, single and composite grain size and number density. The fourth part (chapter 4) describes the validation of MODIS satellite data acquired concurrently with the ground measurements. The radiances collected by the MODIS sensor are converted to ground snow surface reflectances by removing the atmospheric effect using a radiative transfer algorithm (6S). Ground measured reflectance is corrected for ice concentration at the subpixel level so that the in situ and space-borne measured reflectance data are comparable. The fifth part (chapter 5) investigates the single scattering properties (extinction optical depth, single albedo, and the phase function or asymmetry factor) of snow grains (single or composite), which were calculated using the geometrical optical method. A computer code, GOMsnow, is developed and is tested against benchmark results obtained from an exact Mie scattering code (MIE0) and a Monte Carlo code. The sixth part (chapter 6) describes radiative transfer modeling of spectral albedo using a multi-layer snow model with a multiple scattering algorithm (DISORT). The effect of snow stratification on the spectral albedo is explored. The vertical heterogeneity of the snow grain-size and snow mass density is investigated. It is found that optical remote sensing of snow physical parameters from satellite measurements should take the vertical variation of snow physical parameters into account. The albedo of near-infrared bands is more sensitive to the grain-size at the very top snow layer (<5cm), while the albedo of the visible bands is sensitive to the grain-size of a much thicker snow layer. Snow parameters (grain-size, for instance) retrieved with near-infrared channels only represent the very top snow layer (most probably 1--3 cm). Multi-band measurements from visible to near-infrared have the potential to retrieve the vertical profile of snow parameters up to a snow depth limited by the maximum penetration depth of blue light.
    • Optical spectroscopic observations of sprites, blue jets, and elves: Inferred microphysical processes and their macrophysical implications

      Heavner, Matthew James; Sentman, Davis D. (2000)
      During the past decade, several new upper atmospheric phenomena associated with thunderstorms have been discovered. The four main types of optical emissions are now called sprites, blue jets, lves, and halos. Sprites are primarily red and appear between 40--95 km altitude and last between 1--100 ms. The dominant sprite emission is the molecular nitrogen first positive band, a relatively low energy emission also observed in the red lower borders of aurorae. The total optical energy output of a bright sprite is on the order of 50 kJ. Based on spectral observations, the total vibrational and electronic energy deposited in molecular nitrogen and oxygen in the upper atmosphere is 250 MJ-1 GJ. Blue jets last hundreds of milliseconds and span altitudes 15--40 km. Spectral observations of blue jets have not been obtained to date. Elves, the third type of observed optical emissions above thunderstorms, are red emissions at altitudes 75--95 km, lasting one millisecond or less. Elves and halos are similar phenomena, but are distinct based on altitude and duration. Halos typically last 3--6 ms and occur at lower altitudes than elves. This dissertation describes the optical spectrum of sprites obtained by the University of Alaska Fairbanks during summer campaigns of 1995, 1996, and 1998, and its implication to the understanding of the electrodynamics of the middle atmosphere. The single most significant result is the determination that a typical sprite deposits up to one gigajoule into the mesosphere. These forms of electrical energy coupling from tropospheric thunderstorms into the stratosphere, mesosphere, and thermosphere/ionosphere may have critical implications for the global chemistry and energy budgets in these regions.
    • Optimal Inseason Management Of Pink Salmon Given Uncertain Run Sizes And Declining Economic Value

      Su, Zhenming; Adkison, Milo (2001)
      This is a comprehensive study on the fishery and management system (including the inseason stock abundance dynamics, the purse seine fleet dynamics and the inseason management) of pink salmon (Oncorhynchus gorbuscha) in the northern Southeast Alaska inside waters (NSE). Firstly, we presented a hierarchical Bayesian modelling approach (HBM) for estimating salmon escapement abundance and timing from stream count data, which improves estimates in years when data are sparse by "borrowing strength" from counts in other years. We presented a model of escapement and of count data, a hierarchical Bayesian statistical framework, a Gibbs sampling estimation approach for posterior distributions, and model determination techniques. We then applied the HBM to estimating historical escapement parameters for pink salmon returns to Kadashan Creek in Southeast Alaska. Secondly, a simulation study was conducted to compare the performance of the HBM to that of separate maximum likelihood estimation of each year's escapement. We found that the HBM was much better able to estimate escapement parameters in years where few or no counts are made after the peak of escapement. Separate estimates for such years could be wildly inaccurate. However, even a single postpeak count could dramatically improve the estimability of escapement parameters. Third, we defined major stocks and their migratory pathways for the NSE pink salmon. We estimated the escapement timing parameters of these stocks by the HBM. A boxcar migration model was then used to reconstruct the catch and abundance histories for these stocks from 1977 to 1998. Finally, we developed a stochastic simulation model that simulates this fishery and management system. Uncertainties in annual stock size and run timing, fleet dynamics and both preseason and inseason forecasts were accounted for explicitly in this simulation. The simulation model was applied to evaluating four kinds of management strategies with different fishing opening schedules and decision rules. When only flesh quality is concerned, the present and a more aggressive strategy, both of which are adaptive to the run strength of the stocks, are able to provide higher quality fish without compromising the escapement objectives.
    • Optimization of oilfield power distribution through installation of underground transmission lines applied to the Alaskan North Slope

      Mielke, Robert (2004-05)
      An analytical model is developed to evaluate economic feasibility of installing new underground segments to the power transmission system maintained and operated by Greater Prudhoe Bay Central Power Station. Installation of underground segments is considered for intersections of power lines and roadways. Old materials and equipment are abandoned in favor of new technological infrastructure additions to transmission systems. This installation is progressive in its approach; it aims to eliminate superfluous oilfield operations via implementation of technological innovation. Results indicate that installation of underground segments of transmission line is an economically feasible project. Installation sites are chosen that optimize the economics of this investment. Project impact to power reliability, idle rig time, and streamlined rig operations far outweighs the investment associated with this project. Additionally, this project's effect on Prudhoe Bay oil production shows great potential for additional power line burial projects. Hence, it is hoped that this research be considered a pilot project, that future power line burial projects be considered for implementation, and that economic modeling of future projects be accomplished via revision of this work to include comparison of actual vs. predicted economics of this pilot project.
    • Optimizing landbird surveys for detecting population and spatial dynamics

      Mizel, Jeremy D.; Lindberg, Mark; Breed, Greg; Powell, Abby; Schmidt, Joshua (2017-12)
      Landbird populations are undergoing concurrent changes in population size, spatial distribution, and phenology. The sensitivity of landbird monitoring programs to detect and distinguish these varied processes is of critical importance. Consequently, these efforts require inference methods that are efficient and fully leverage information about spatial, population, and phenological dynamics. The development of efficient inference methods can be addressed in part through a thorough understanding of how the data are actually generated, the application of sampling methods that attempt to maximize encounter probability, and the tailoring of sampling methods to maximize sensitivity to specific inference objectives. Chapter one of this dissertation is concerned with accommodating temporary emigration in spatial distance sampling models. Model-based distance sampling is commonly used to understand spatial variation in the density of wildlife species. The standard approach is to assume that individuals are distributed uniformly in space and model spatial variation in abundance using plot-level effects. Thinned point process models for surveys of unmarked populations (spatial distance sampling) frame the sampling process in terms of the individual encounter in space and, consequently, are expected to offer greater sensitivity for understanding spatial processes. However, existing spatial distance sampling approaches are conditioned on the assumption that all individuals are present and available for sampling. Temporary emigration of individuals can therefore result in biased estimates of abundance. Herein, I extend spatial distance sampling models to accommodate temporary emigration. A simulation study indicated more precise and less biased estimation under the spatial distance sampling model compared to models that assume a uniform distribution of individuals and assess spatial variation in abundance using plot-level effects. An applied example involving two arctic-breeding passerines indicated considerably stronger inference under the spatial distance sampling model than standard distance sampling models. Chapter two is concerned with the capacity of subarctic passerines to adjust their arrival timing to relatively extreme variation in spring conditions. I assessed interannual variation in passerine arrival timing in Denali National Park, Alaska from 1995-2015, a period that included both the warmest and coldest recorded mean spring temperatures for the park. Neotropical-Nearctic migrants varied in terms of the flexibility of their arrival timing, but generally showed plastic phenologies, suggesting resilience under extreme spring conditions. In comparison, Nearctic-Nearctic migrants showed similar or greater plasticity in arrival timing. A majority of species showed synchronous-asynchronous fluctuation in arrival (i.e., synchronous arrival in some years, asynchronous in others) in combination with various levels of the mean response (i.e., early, average, and late arrival), suggesting the presence of interactions between environmental conditions at multiple scales and inter-individual variation. Overall, these findings suggest that monitoring of the mean-variance relationship may lead to a deeper understanding of the factors shaping phenological responses. Chapter three is concerned with developing efficient inference methods for inventorying and monitoring cliff-nesting raptor populations. In nest occupancy studies of cliff-nesting raptors, the standard approach is to allocate a level of survey effort that is assumed to ensure that the occupancy state is known with certainty. However, allocating effort in this manner is inefficient, particularly at landscape scales, constraining our capacity for effective management of these species. To increase survey efficiency and expand the spatial inference of these studies, I developed two versions of a multi-state, time-removal model, one for long-term monitoring studies and another for population inventories or single-season surveys in which there is no prior knowledge of nest locations. For long-term monitoring of species with alternative nests, I formulated a version of the model that accounts for state uncertainty at the territory-level caused by a failure to observe all nests within a territory. Simulation studies indicated generally low to moderate relative bias under the monitoring and inventory models. In addition, I applied the monitoring model to a long-term study of golden eagles (Aquila chrysaetos) in Alaska and demonstrate that the maximum effort spent on any nesting territory could be reduced by up to almost 90% of that recommended by standard protocols.
    • Order reduction and eigenstructure assignment for nonsmooth vibrating systems: a nonlinear normal modes approach

      Lu, Rongdong (2002-08)
      Two related problems are addressed in this thesis. The first one is for order reduction of conservative vibrating systems with piecewise linear nonsmooth nonlinearities of arbitrary dimension. Linear-based, PMM-based and LELSM-based order reduction transformations are applied. The technique is applied to multi-degree-of-freedom systems with nonsmooth clearance, deadzone, bang-bang, and saturation nonlinearities. The resulting approximate frequencies are compared with those obtained from numerical simulations. The second technique is eigenstructure assignment of n-degree-of-freedom conservative vibrating systems with nonsmooth nonlinearities. Three distinct control strategies which utilize methods for approximating the NNM frequencies and mode shapes are employed. First, PMM for approximating NNM frequencies is used to determine n constant actuator gains for eigenvalue placement. Second, an approximate single-degree-of-freedom reduced model is found with one actuator gain for the mode to be controlled. The third strategy allows the frequencies and mode shapes (eigenstructure) to be placed by using a full n x n matrix of actuator gains and employing LELSM for approximating NNM frequencies and mode shapes.
    • Organic matter accumulation and preservation in Alaskan continental margin sediments

      Ding, Xiaoling; Henrichs, Susan M. (1998)
      Continental margin sediments provide a historical record of the sources and fate of organic matter (OM) originating both from the continents and from primary productivity in the overlying water column. However, since this record can be altered by microbial decomposition within the sediment, the history cannot be interpreted without understanding how decomposition can affect OM composition. Also, the margins accumulate much of the OM buried in ocean sediments; hence, knowledge of processes influencing preservation of OM in these sediments is essential to understanding the global carbon cycle. OM preservation was examined using two approaches. First, I studied sediments in the northeastern Gulf of Alaska to determine sources of OM and temporal changes in carbon accumulation. A large amount of OM, 45--70 x 104 tons/yr, accumulated in this region, about 50% from terrestrial sources. Most of the sediment cores showed little evidence of change in TOC, TN, or C and N stable isotope compositions due to decomposition within the sediment. Second, I investigated the processes that control OM preservation, focusing on the role of the OM adsorption to mineral surfaces. Because proteins are major constituents of sedimentary OM, I examined factors controlling their adsorption, decomposition, and preservation. Three hydrophilic proteins were strongly adsorbed by two clay minerals, an iron oxide, sub-oxic sediments from Resurrection Bay (RB), Alaska, and anoxic sediments from Skan Bay (SB), Alaska. The partition coefficients were large enough to lead to their preservation provided that the proteins did not decompose while adsorbed. Generally, adsorption of proteins to solid phases decreased decomposition rates, suggesting that adsorption is important in protecting these compounds from microbial attack. Greater protein decomposition rates were found in SB than in RB sediments, indicating that anoxia did not inhibit protein biodegradation. Naturally-occurring adsorbed proteins were extracted from SB and RB sediments using a detergent solution. Most of these adsorbed proteins were small (<12 kDa), indicating that only the proteins adsorbed within the micropores of particle surfaces are preserved long-term.
    • Organic matter sources on the Chukchi Sea shelf in a changing Arctic

      Zinkann, Ann-Christine; Iken, Katrin; Wooller, Matthew; Danielson, Seth; Leigh, Mary Beth; Gibson, Georgina (2020-05)
      Climate-change induced alterations of the organic matter flow from various primary production sources to the benthic system in the Arctic Chukchi Sea could have major implications on carbon cycling, sequestration, and benthic food web structure sustaining upper trophic levels. In particular, the role and contribution of terrestrial matter and bacterial matter could become more prominent, with increasing erosion and permafrost melt being discharged from land, and warming water temperatures raising bacterial metabolism. In this study, I used essential amino acid (EAA) specific stable isotope analysis to trace the proportional contributions of bacterial, phytoplankton, and terrestrial organic matter in sediments, as well as benthic invertebrates on the Chukchi Sea shelf. Across the upper 5 cm of sediments, most organic matter sources were equally distributed, except for a slight decrease with depth in phytoplankton EAA. Terrestrial sources contributed the majority of EAA (~76 %) in all sediment layers, suggesting a potential accumulation of this material due to slow degradation processes. These results indicate a well-mixed upper sediment horizon, possibly due to bioturbation activity by the abundant benthos. Experimental observations of increases in bacterial production, measured as phospholipid fatty acid (PLFA) production, at water temperatures 5 °C above ambient (0 °C) and under sufficient substrate conditions suggest that bacterial organic matter in sediments could become a greater organic matter source in the sediments of a future, warmer Arctic. EAA source contribution to various benthic invertebrate feeding types (FT) were similar but showed significant differences among genera within the same FT, suggesting that feeding habits are more genus-specific rather than FT-specific. These differences were attributed to variations in other characteristics such as mobility, selectivity, and assimilation efficiency. Terrestrial EAA contributed high amounts to all benthic genera, supporting other recent findings that this source is readily utilized by benthic invertebrate consumers. These results of organic matter source contributions across sediments and benthic invertebrate feeding types were then used to better resolve the detrital pathways in an Ecopath mass-balance model of the Chukchi Sea. The incorporation of terrestrial matter as an organic matter source to Chukchi Sea food webs and updated organic matter use in benthic invertebrate diets balanced energy flow from phytoplankton and bacterial production through the food web. Simulations of potential future reductions of the pelagic production to the benthos negatively impacted benthic feeding taxa, which could be partially compensated by a simulated increase in terrestrial and bacterial organic matter supply.
    • Organizational communication and culture in female predominated workplaces

      Comstock, Sarah Rush (2000-05)
      While equality of the sexes has still not been achieved, the ongoing struggle for parity has paved the way for an influx of females into workplaces. In many organizations this increase has resulted in a higher ratio of females to males. Offices that are predominated by on sex or the other create communication problems, attitudes, and ways of dealing with co-workers on an interpersonal level that organizations with a balance between males and females do not face. This study will explore the perspective of females working in gender predominant organizations, and also observations on organizational culture; intra-organizational communication; communicated support among organizational members; and the overall uniqueness of the organization.
    • Organizational culture and meanings in tension: an analysis of the Alaska Volcano Observatory

      Worley, Shelly Lisa (2000-05)
      The Alaska Volcano Observatory (AVO) is an organization that is responsible for observing volcanic activity in Alaska and surrounding regions. This organization has a great impact on the public and agencies in Alaska because it is responsible for ensuring the safety of many Alaskans, and to many people who live in neighboring regions. AVO is not only responsible for saving lives, but also responsible for notifying agencies that depend on this organization for volcanic crisis notification. This study is an ethnography of the Alaska Volcano Observatory and through interpretation of my data as research too, I provide a sense of place for this organization. Detailed journals of my experience as a member of this organization have been analyzed to understand the culture of the place.
    • Organochlorines In Steller Sea Lions (Eumetopias Jubatus)

      Myers, Matthew John; Atkinson, Shannon; Krahn, Margaret; Rea, Lorrie; Castellini, Michael; Mellish, Jo-Ann; Burdin, Alexander (2009)
      Existing populations of Steller sea lions (Eumetopias jubatus ) have declined precipitously over the last half-century. Investigations into the cause of this downward trend have focused on many different possible factors. Toxicity caused by the accumulation of organochlorines (OCs), such as polychlorinated biphenyls (PCBs) and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane or dichlorodiphenyltrichloroethane (DDT), has been demonstrated in marine mammals and was considered here as one possible factor that may have contributed to the decline of Steller sea lions or their failure to recover. The focus of this project was to investigate the relationship of contaminant loads to hormone levels, specifically thyroid hormones and cortisol in Steller sea lions. Two approaches were taken to this study. Firstly, baseline hormone concentrations were identified for the thyroid hormones, thyroxine (T 4) and triiodothyronine (T3), and cortisol. This involves comparison and extrapolation. Secondly, possible risk effects were examined by comparing levels of OCs in captive and free-ranging Steller sea lions to known effects in related species with known physiological thresholds. Serum concentrations of total T4 were highest in Steller sea lions followed by total T3 concentrations. Concentrations of free T4 and free T3 were three to four orders of magnitude lower. Concentrations for all four thyroid hormone measurements tended to a lower level as animals matured beyond the neonatal stage. When thyroid hormones from captive sea lions were evaluated across seasons, all thyroid hormones were highest in the July to September period. Cortisol concentrations were similar in male and female pups. Cortisol varied with age but when considered in regards to time of year when sampled, followed a seasonal pattern. Cortisol was elevated in fall months in captive sea lions (non-pups), which is similar to what is seen in other marine mammals and is likely associated with the annual molt. Male pups from Alaska had lower levels of SigmaPCBs and SigmaDDT when compared to male pups from Russia. Female pups from Alaska were significantly lower in SigmaPCBs than Russian female pups as were female pups for SigmaDDT levels between areas. Anywhere from 12 to 64% (depending on rookery) of Steller sea lion pups investigated for contaminants had concentrations of SigmaPCBs that are high enough to cause physiological problems. Concentrations in blood taken monthly for 2 years in three captive Steller sea lions were similar at any given sampling time and followed a seasonal pattern with levels significantly higher in the summer months of July to September and lower in the three month winter period January to March. Concentrations of OCs in blubber samples collected quarterly for the captive females followed an analogous pattern to blood samples but the captive male sea lion was considerably lower and declined over the study period. A significant relationship between blubber contaminants and lipids was noted in the three captive Steller sea lions. Even though OC contamination has not been hypothesized to be the primary factor that precipitated the population decline, there is a potential for these chemicals to have a negative effect on the health of free-ranging Steller sea lions. These data suggest that concentrations of OCs in Steller sea lions may be high enough to cause endocrine or reproductive dysfunction and could potentially impact fertility or fecundity. Therefore, OC contaminants can not be dismissed as a contributing source to either the decline or the failure to recover of the Steller sea lion population.
    • The origin and composition of aerosols in the Alaskan airshed

      Wilcox, Walter James (2001-12)
      Since the Alaskan airshed north of the Alaska Range receives a substantial portion of its anthropogenic aerosol and gaseous pollutants through long-range transport, Alaskan air quality is influenced to an unusually high degree by the political and economic events of other countries. An understanding of the political and economic forces at work in the various circumpolar nations is key to an understanding of the observed decline in Arctic haze, the present state of Arctic air pollution, and likely future developments. It is shown in this thesis that Arctic haze has declined in Interior Alaska over the last decade and a half. This decline appears to be driven by the widespread emission reductions which have occurred in North America, Europe, and the former Soviet Union (FSU) between 1988 and 1998. If true, this linkage indicates that the story of Arctic haze is not yet a post-mortem. EMEP projections for 2005 foresee a continuing decline in emissions across Europe and a leveling off in North America, but emissions in the European FSU are expected to double by 2005. Events in the FSU, and perhaps Asia as well, threaten to abrogate any further progress made by Europe and North America and could perhaps revive the phenomenon.
    • Origin, character, application and correlation of tephra partings in tertiary coal beds of the Kenai Peninsula, Alaska

      Reinink-Smith, Linda Margareta; Hopkins, David M. (1989)
      Volcanic and non-volcanic partings occur in coal beds of the Neogene Beluga and Sterling Formations along the shores of the Kenai lowland, Alaska. The partings were systematically characterized to determine their potential geological applications: Two-thirds of the partings originated as air-fall tephra. Of these, partly altered, Pliocene tephra typically contain volcanic glass + feldspar $\pm$ montmorillonite $\pm$ quartz $\pm$ kaolinite $\pm$ opal-CT. Highly altered Miocene partings are characterized by feldspar $\pm$ kaolinite $\pm$ montmorillonite $\pm$ quartz $\pm$ crandallite $\pm$ altered volcanic glass, where crandallite appears to have formed by replacement of volcanic glass prior to clay formation. About one-third of the partings are of detrital origin and contain detrital chlorite + illite + smectite + quartz $\pm$ feldspar $\pm$ siderite $\pm$ kaolinite. A Pliocene pumice parting near the top of the Sterling Formation was correlated from the northwestern to the southeastern Kenai lowland on the basis of similar glass morphologies, an absence of opaque minerals, and geochemical similarities. A crystal-tuff near the middle of the section could be traced across the Kenai lowland as one or two ash-falls, based on inertinite contents of adjacent coal, mineralogy, and geochemistry. Some other prominent tephras could not be correlated. The tephra partings are time-equivalent to DSDP cores from the Gulf of Alaska and along the Aleutian Island chain. Tephras occur every 125-500 yr in the lower part of the Beluga Formation, and their deposition probably coincides with a volcanic pulse 10.5 m.y. ago. This pulse is not well recorded in nearby DSDP cores. In the upper part of the Beluga Formation, during volcanic quiescence, tephras are recorded at an average rate of one every 9,000 yr. Time equivalent DSDP cores show a near absence of tephras. A volcanic pulse occurred during the deposition of the lower Sterling Formation, about 7.5 m.y. ago, with intervals between volcanism which averages 11,000 yr or longer. Volcanic sources appear to have been distant, which is consistent with an absence of tephra layers in a Gulf of Alaska core. About 5 m.y. ago, concurrent with the deposition of the upper Sterling Formation, the thicknesses of the tephra layers dramatically increase and the frequency increases to an average of one tephra every 2,000 years. This increase is recorded in DSDP cores as well.
    • Origins And Zoning Of The Buckhorn Gold Skarn, Ne Washington

      Deal, Michelle L.; Newberry, Rainer (2012)
      The Buckhorn Deposit was discovered in the mid 1980's and is composed of two separate Au-Bi deposits: the Gold Bowl and the Southwest Zone. The Southwest Zone is the larger of the two and is blind and stratabound. The Gold Bowl is exposed on the surface. Jurassic and Eocene plutonic rocks are present in the immediate area, indicating a complex geologic history and two potential mineralization ages. To determine the source- and thus the age- of gold mineralization I use chemical analyses of (>300) igneous rocks, X-ray Fluorescence (XRF) determination of (>200) Bi/Au, Cu/Au, and Cu/Pb ratios throughout the ore zones, Fe:Mg ratios of skarn clinopyroxenes determined by EMP analyses, calc-silicate mineral zoning, surface and underground mapping, and Ar40/Ar39 dating of Au-intergrown skarn hornblende. Chemical classification of igneous rocks distinguishes seven potential source intrusions in the immediate Buckhorn area. Metal zoning (Bi/Au, Cu/Au, and Cu/Pb) throughout the entire deposit showcases the lack of relationship between the Gold Bowl and the Southwest Zone, allowing for multiple source and remobilization interpretations. However, the techniques employed all indicate an east to west ore fluid migration across the Southwest Zone and reveal a newly-unrecognized zoned Jurassic pluton SE and below the deposit as the source.
    • Osteological stress markers and habitual behaviors: analyzing the connection at Hierakonpolis, Egypt

      Denton, Nora Lee Cross (2005-05)
      The current project identifies skeletal patterns that indicate habitual behavior using muscle attachment sites, osteoarthritic changes and long-bone robusticity. Using a sample from HK43, a cemetery used by the Naqada II A-C working class (circa 3,800-3,400 B.C.), patterns were determined with respect to sex, and by age group. Those patterns were then compared to hypothesized models of skeletal markers predicted to occur with habitual use of an Egyptian hoe, an ox-drawn ard-style plow, a shaduf (a simple machine used in irrigation), and grinding grain using a saddle quern and grinding stone. The patterns displayed in the sample population correspond to predicted patterns created by habitual activity. Results were determined twice; first by sex, then by age. Females and males were grouped regardless of age, and vice versa. If divided by both, the resulting groups were too small to be compared. Females demonstrated a pattern that was most consistent with grinding grain. Males were determined to have a pattern most consistent with hoeing and using a shaduf The middle adult age group, composed of both males and females, showed a range of skeletal markers that is most consistent with that predicted for plowing. Not all patterns were easily explained, however. The young adult, or 17-24 year old age group displayed a pattern of muscle attachment very similar to the old adult group,>45 years of age. The source of that apparent similarity will have to be addressed by further research at Hierakonpolis, Egypt.
    • Osteology, relationships and paleoecology of a new Arctic hadrosaurid (Dinosauria: ornithopoda) from the Prince Creek formation of Northern Alaska

      Mori, Hirotsugu; Druckeniller, Patrick; Fowell, Sarah; Wooller, Matthew; Hundertmark, Kris (2014-05)
      The Liscomb Bonebed (LBB), found in the early Maastrichtian Prince Creek Formation of northern Alaska, is the single most productive site for the Arctic dinosaurs in either hemisphere. From the LBB, thousands of bones representing at least hundreds of individuals of a saurolophine hadrosaur have been collected, but they have not been previously described and their taxonomic status remains unresolved. In part, this stems from the fact that most material comes from individuals approximately one-half to onefourth of adult size. Another long-standing question concerns whether dinosaurs in the Prince Creek Formation overwintered in the paleo-Arctic or migrated elsewhere (presumably south) to escape prolonged darkness and cold. Here, I attempt to determine the taxonomic status of the LBB hadrosaurs using three semi-independent methods: 1) geometric morphometric analysis; 2) comparative morphological analysis; and 3) cladistic analysis. An important component of this work also includes an ontogenetic study of the growth patterns of the genus Edmontosaurus, to which this material has been previously referred, in order to better understand ontogenetic variation within the Alaskan taxon. My results indicate the Alaskan taxon is a new species of the widespread genus Edmontosaurus. For the first time, the Alaskan taxon is described in detail, making it the best known polar dinosaur to date. My cladistic analysis suggests a possible biogeographic scenario in which the common ancestor of Edmontosaurus and Shantungosaurus originated in eastern Eurasia and then dispersed by the Campanian to North America via a land corridor in the area of present day Alaska. Finally, I used a novel method involving strontium isotope geochemistry to test the migration hypothesis of the new species of Alaskan Edmontosaurus. I measured strontium in tooth enamel of Edmontosaurus and a putative non-migratory species (Troodon) using LA-MC-ICP-MS. My results suggest diagenesis had not significantly altered the signal and that Alaskan Edmontosaurus likely did not migrate during approximately the last four months of life. My results lend further support for the existence of a distinct, early Maastrichtian polar dinosaur fauna known as the Paanaqtat Province.
    • Otters, sea stars, and glacial melt: top-down and bottom-up factors that influence kelp communities

      Traiger, Sarah B.; Konar, Brenda; Hardy, Sarah; Okkonen, Stephen; Edwards, Matthew; Litaker, Wayne (2017-08)
      Kelp beds are important features of the Alaska coastline and provide habitat, protect coastlines, and support commercial and subsistence harvests. Kelp beds are affected by top-down and bottom-up factors, which are changing due to human and climate-related impacts. The influences of these top-down and bottom-up factors on kelp beds are investigated in three chapters. My first chapter investigated the influence of glacial discharge on recruitment and early community development in subtidal kelp communities by monitoring benthic sessile algae and invertebrates on cleared rocks across a glacial gradient along with various physical and biological parameters in the summers of 2013-2014. It has been predicted that Alaska's glaciers will lose 30-60% of their volume by 2100. The melt from glaciers increases sedimentation and lowers salinity, impacting important habitat-providing kelp. I found that sites upstream from glacial discharge had higher kelp recruitment than downstream sites, and that up to 72% of the variation in community development was related to mobile invertebrates and kelp in the surrounding community. Glacially-influenced environmental factors did not explain any variation that was not already explained by biological factors. My second chapter explored whether patterns in the recruitment of the dominant canopy kelp, Nereocystis luetkeana and the subcanopy kelp, Saccharina latissima were a result of dispersal limitation or failure to grow to macroscopic size. My goals were to determine 1) whether glacial melt conditions affect adult fecundity (spore production) of either species, 2) how sedimentation affects early gametophyte growth and survival in each species, and 3) whether competitive interaction between species at the gametophyte stage is altered by sediments. I found that glacial melt conditions did not affect the fecundity of either species, but sedimentation affected survival and competition. Saccharina latissima was the superior competitor under high sediment conditions. Because glacially-influenced coastal areas often have little exposed hard substrate and predation by sea otters and sea stars on clams can provide hard substrate for kelp colonization, my third chapter examined methods for determining predation on clams by these predators without direct observation. I found that foraging pits of sea otters and sea stars could not be distinguished using quantitative measurements. In contrast, shell litter proved useful in quantifying relative foraging rates. Clam consumption by sea otters and sea stars was equal at all but one site. Collectively, my thesis chapters provide information on the effects of glacial discharge on microscopic and early kelp life stages in Alaska which can be incorporated into management practices.
    • Outbreeding depression and inheritance in three generations of geographically distinct southeast Alaska coho salmon (Oncorhynchus kisutch) populations

      Dann, Tyler H. (2009-08)
      I observed no fitness losses among F₂ hybrids of three Southeast Alaska coho salmon (Oncorhynchus kisutch) populations relative to parental controls. Marine survival did not differ among groups in one generation, but was greater for hybrids than controls in another, although the power of these tests was low. Increases in fluctuating asymmetry, which can signal losses in fitness, were not observed. Line cross analyses of length suggested additive and additive plus dominance gene action, and two of three analyses suggested epistasis. In contrast, meristic characters exhibited little variability; and in most cases tests failed to reject a simple additive model. Half- and full-sib analyses provided no evidence of quantitative genetic variation for any trait although the power to detect these effects was low. Comparisons of population divergence measured by quantitative traits (Qst) and molecular markers (Fst) that length is an adaptive trait and that bilateral meristics are highly conserved. Although we did not observe losses in fitness, the power of our tests was low, the among-population differences were unique to our experiment and so results of this study should be interpreted with caution.
    • Outbreeding depression in hybrids between spatially separated pink salmon (Oncorhynchus gorbuscha) populations: marine survival, homing ability, and variability in family size

      Gilk, Sara E. (2003-05)
      Hybridization between distinct populations of salmon can cause fitness loss (outbreeding depression), and may result in reduced survival. The erosion of fitness-related traits such as homing ability and change in family size distribution may underlie reduced survival. Out breeding depression was investigated in two independent experiments that made hybrids between geographically separated and genetically divergent pink salmon populations. Control crosses were made from male and female Auke Creek (Southeast Alaska) pink salmon and hybrid crosses were between Auke Creek females and Pillar Creek (Kodiak Island, about 1000km away) males. Parentage assignment from microsatellite analysis improved estimates of survival and straying, and was used to examine variation in family size. The return rates of even-broodyear F 1 control and hybrid fish were similar, but the odd-broodyear F 1 control returns exceeded hybrid returns. The F 2 control returns exceeded hybrid returns in both the even- and odd broodyears. Hybridization did not impair homing ability; weekly surveys in nearby ( - lkm) Waydelich Creek revealed similar straying rates from Auke Creek by both hybrid and control fish in all years. Family data were available only for even-broodyear returns; hybridization did not increase the index of variability (ratio of variance to mean) in family size in these years. Outbreeding depression in hybrids of geographically separated populations demonstrates the potential for introgression of nonnative fish to erode natural production.