• Prehistoric toolstone procurement and land use in the Tangle Lakes Region, central Alaska

      Lawler, Brooks A.; Potter, Ben A.; Reuther, Joshua D.; Newberry, Rainer; Hemphill, Brian (2019-05)
      This project explores prehistoric human mobility and landscape use in the Tangle Lakes region, central Alaska through analyses of toolstone procurement and manufacture conditioned by site function. Early Holocene Denali and middle Holocene Northern Archaic traditions are hypothesized to have different tool typologies, subsistence economies, and land use strategies. However, few large, systematic studies of toolstone procurement and use have been conducted. At a methodological level, archaeologists have struggled to quantitatively source non-igneous cryptocrystalline toolstone which often makes up the largest proportion of archaeological lithic assemblages. These problems were addressed by developing rigorous chemical methods for statistically assigning lithic from Tangle Lakes assemblages to (a) two known local toolstone quarries, (b) materials within the Tangle Lakes region, and (c) non-local materials. Lithic technological and geospatial analyses were used to evaluate toolstone procurement, manufacture, and use within sites. Lithic samples from four archaeological components located at different distances from their nearest known quarry sources were used to address the research problems. The archaeological samples were derived from a Denali complex hunting site (Whitmore Ridge Component 1) and three Northern Archaic assemblages: a residential site (XMH-35), a tool production site (Landmark Gap Trail) and a hunting camp (Whitmore Ridge Component 2). Chemical results indicate that cryptocrystalline material in Tangle Lakes assemblages can be statistically assigned to primary sources locations, and visual sourcing of this material is entirely unreliable. Lithic analytical results indicate that despite slight changes in mobility strategies for Denali and Northern Archaic populations, site function is the strongest conditioning factor for material selection and procurement strategies local to the Tangle Lakes region. Thus, this research provides (a) best practice methods for sourcing abundance cryptocrystalline material that has been precluded from most lithic sourcing studies, and (b) the data necessary to incorporate technological organization strategies of Tangle Lakes populations into the broader context of Denali and Northern Archaic behavioral patterns in Alaska.
    • Preliminary assessment of effectiveness of precut technique in controlling transverse cracks for asphalt pavement in Interior Alaska

      Netardus, John Jaro; Liu, Juanyu; Zhang, Xiong; Shur, Yuri; Saboundjian, Steve (2016-05)
      Transverse thermal cracking is one of the most common pavement distresses on asphalt pavements in cold climates. Transverse cracks are costly to maintain and unpleasant to drive over. The State of Alaska Department of Transportation and Public Facilities must seal cracks every summer to prevent further road damage from occurring. A simple solution that is gaining support is the precut technique where saw cuts are installed perpendicular to the road centerline shortly after construction to help relieve thermal stresses that cause cracking. This technique has effectively reduced the effects of natural transverse thermal cracking in other states as well as in Fairbanks, Alaska. This study investigates two road construction projects that include precuts with variable factors including three precut spacing intervals, five precut depths, and five pavement structures. Costs to install precuts are also compared against the cost to maintain a section without precuts in a preliminary cost effective analysis. Crack survey data from both projects have revealed that precutting does reduce transverse thermal cracking. Shorter precut spacing, placing precuts where natural cracks existed prior to construction, deeper precuts, and stronger pavement structures provided the best results. Further observations and more accurate cost data are recommended for an absolute determination of cost effectiveness.
    • Preparing Culturally Responsive Teachers Of Science, Technology, Engineering, And Math Using The Geophysical Institute Framework For Professional Development In Alaska

      Berry Bertram, Kathryn; Barnhardt, Raymond; McMillan, Claude III; Kramm, Gerhard; Smith, Roger (2011)
      The Geophysical Institute (GI) Framework for Professional Development was designed to prepare culturally responsive teachers of science, technology, engineering, and math (STEM). Professional development programs based on the framework are created for rural Alaskan teachers who instruct diverse classrooms that include indigenous students. This dissertation was written in response to the question, "Under what circumstances is the GI Framework for Professional Development effective in preparing culturally responsive teachers of science, technology, engineering, and math?" Research was conducted on two professional development programs based on the GI Framework: the Arctic Climate Modeling Program (ACMP) and the Science Teacher Education Program (STEP). Both programs were created by backward design to student learning goals aligned with Alaska standards and rooted in principles of indigenous ideology. Both were created with input from Alaska Native cultural knowledge bearers, Arctic scientists, education researchers, school administrators, and master teachers with extensive instructional experience. Both provide integrated instruction reflective of authentic Arctic research practices, and training in diverse methods shown to increase indigenous student STEM engagement. While based on the same framework, these programs were chosen for research because they offer distinctly different training venues for K-12 teachers. STEP offered two-week summer institutes on the UAF campus for more than 175 teachers from 33 Alaska school districts. By contrast, ACMP served 165 teachers from one rural Alaska school district along the Bering Strait. Due to challenges in making professional development opportunities accessible to all teachers in this geographically isolated district, ACMP offered a year-round mix of in-person, long-distance, online, and local training. Discussion centers on a comparison of the strategies used by each program to address GI Framework cornerstones, on methodologies used to conduct program research, and on findings obtained. Research indicates that in both situations the GI Framework for Professional Development was effective in preparing culturally responsive STEM teachers. Implications of these findings and recommendations for future research are discussed in the conclusion.
    • The President's Commission on Pornography

      Vorro, Amy E. (2006-05)
      The poems in this collection reflect various forms of maturation and their parallels with historic cultural shifts, specifically those typified in pop culture by the perceived climate of the 1970's. The poems contained in the first section, Deep Throat, focus on moments, taking the variables of place and sexuality heavily into account so as to explore 'the unmentionable' and their resonances for both the specifically female and generally human conditions, while simultaneously examining the personal implications. Debbie Does Dallas, the second section, continues along this vein, yet branches out to contemplate more imagined encounters and more specific taboos, sometimes through the use of traditional poetic forms. The third and final section, Behind the Green Door, steps through a doorway into the past: applying the same topics of maturation, taboos and sexuality to family structure, childhood and memory. The President's Commission on Pornography relies heavily on eccentric juxtaposition so as to stretch and investigate the amorphous boundaries of taboos, language and sexuality
    • Prestocking assessment of the prevalence and intensity of Diphyllobothrium ditremum (Creplin) plerocercoids in freshwater barriered lakes in Alaska

      Weiland, Keith Alan (1989-05)
      Plerocercoids of the pseudophyllidean cestode Diphyllobothrium ditremum (Creplin, 1825) have significantly affected the success of using certain barriered lakes for the rearing, overwintering and smolting of juvenile coho (Oncorhynchus kisutch) and Chinook (Oncorhynchus tshawytscha) salmon by causing mass mortalities of these host fishes. The prevalence of cestode procercoids in copepods, the first intermediate host, was propose as a method for assessing the potential for cestode caused losses of salmon prior to stocking a lake. However, no procercoids were found in a total of 15,276 Diaptomus and 435 Cyclops spp. from three lakes on south Baranof Island examined for procercoids. Diaptomus kenai is suggested as the first intermediate host for Diphyllobothrium ditremum. despite the absence of procercoids in any specimens examined. Diaptomus kenai was the predominant copepod in the three lakes studied, and was the prey item occurring most frequently (percent occurrence, 73.7%) in the stomach contents of 95 resident coho. Coho, Chinook, and rainbow trout (Salmo gairdneri) were obvious second intermediate hosts of D. ditremum. Among three species of piscivorous birds examined from the lake sites, a single common merganser (Merqus merganser) contained seven mature worms resembling D. ditremum. A bioassay study using coho salmon fingerlings in net pens suspended within a "cestode infested" lake proved successful as an assessment method. Plerocercoids of D. ditremum were observed in 91% of the planted coho within twenty days of exposure in Osprey Lake. Coho mortalities of 46.2% and 22.4% were observed in two pens. Mean plerocercoid intensities for apparently normal, moribund, and dead coho were 11, 28, and 32 respectively. Moribund and dead coho each had significantly larger worm loads than apparently normal coho. Primary lesions observed from gross and histopathological examinations of parasitized coho from Elfendahl and Osprey lakes included: ascites with marked distension of the abdomen; hemorrhaging of viscera primarily adipose tissue and liver; and focal necrosis of organs from migrating plerocercoids.
    • Pretreatment of aqueous phase of mine plant tailings for submarine disposal

      Choudhury, Abhishek; Bandopadhyay, Sukumar; Lin, Steve; Schiewer, Silke; Ganguli, Rajive; Wilson, Terril E. (2005-12)
      Submarine disposal of mine tailings is a relatively recent technology that holds the promise of solving the recurring problems that the mining industry has had with tailings disposal. The system has been successfully implemented in many mines around the world. Before implementation, however, a decision needs to be made whether the biogeochemical characteristics of the area selected for submarine disposal and characteristics of the tailings are conducive to implement submarine disposal of tailings. While an expert system can decide the feasibility of submarine tailings disposal (STD) based on its database of information and decision loops for the critical factors, tailings cannot be disposed of under water without pretreatment, which is the focus of this thesis. Bioremediation, freeze concentration and reverse osmosis were examined as possible alternatives for treatment. Laboratory tests were performed for all the methods, and in the case of bioremediation, pilot scale tests were also performed. It was concluded that all the three methods remove dissolved metals from mine water to varying degrees. Reverse osmosis was found to be the most efficient method, while freeze concentration was the least efficient method.
    • Preventing recidivism by using the theory of reintegrative shaming with conferences

      Enters, Patrick G.; Jarrett, Brian; Daku, Michael; Duke, J. Robert; May, Jeff (2013-06)
      Driving while intoxicated in the United States is a major problem with more than 31 percent of national driving fatalities caused by intoxicated drivers. The purpose of the present study is to identify the possibility between the use of reintegrative shaming with conferences and the likelihood that it will reduce the recidivism of driving while intoxicated. The study explores John Brathwaite's theory on reintegrative shaming and how that theory applies in conferences. The emerging theory o f Storylines from Robert Agnew is also explored in its importance when conducting these conferences. Studies conducted in Australia, Pennsylvania, Kansas and Alaska have all suggested that the use of conferences, especially those which utilize reintegrative shaming and reintegrating offenders back into the community reduces the recidivism rates. The research found in this article helps point future studies to examine offenders in a longer term after they have completed reintegrative shaming programs and conferences.
    • Prey consumption by juvenile salmonids on the Taku River, southeast Alaska

      Brownlee, Kevin (1991-05)
      Stomach contents were collected from juvenile salmonids (genus Oncorhynchus and Salvelinus) from habitats on the Taku River in 1987. Differences were defined between groups of fry. A linear discriminant function (LDF) analysis was applied to prey frequencies grouped by species, habitat, and period. The analysis discriminated between: fish in beaver ponds; sockeye in side-slough sites and fish from other mainstem sites; and beaver ponds and mainstem sites. An exclusion experiment was established in a beaver pond. The diet of sockeye (O. nerka) and coho (O. kisutch) fry was sampled from allopatric and sympatric treatment enclosures. LDF analysis applied to prey categories assigned group membership between species, treatment, and period factors. A log-linear analysis yielded significant interaction effects between the treatment, habitat, and. period explanatory variables and the response, prey, confirming the influence of the presence of cogenerics on prey consumed.
    • Prey relationships between juvenile pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon in Prince William Sound, Alaska

      Barnard, David (1981-05)
      The food relationships between juvenile pink salmon (Oncorhynchus gorbusaha) and chum salmon (O. keta) released from a hatchery Prince William Sound are examined. Samples of zooplankton and salmon fry were collected from nearshore waters adjacent to the hatchery. Salmon fry in this area have little opportunity for spatial segregation by habitat and are obliged to use common food resources. An electivity index shows that both salmon fry species selectively prey upon available zooplankton. The diets of the two salmon species are compared using a measure of overlap, Cλ, which is calculated using numerical (percent number) and mass (percent dry weight) data from stomach analyses. Values of Cλ calculated from numerical data show a moderate degree of food overlap. Values of Cλ calculated from mass data, however, show less overlap. It is concluded that on a basis of diet biomass, these two species of salmon fry effectively partition food resources.
    • Prey selectivity and diet overlap in juvenile pink, chum and sockeye salmon in the Gulf of Alaska and Prince William Sound, Alaska

      Blikshteyn, Mikhail A. (2005-12)
      Pink, chum and sockeye salmon are the three most commercially important Pacific salmon. As juveniles, they co-occur in coastal waters of Alaska. To assess the potential for competition among juveniles of these species, I examined their diets in Prince William Sound and in nearby continental shelf waters in the summer and fall of 2001 and quantified surface zooplankton at the same sampling stations. I estimated diet diversity, diet overlap and prey selectivity of the three species. A large proportion of gelatinous prey, especially larvaceans, characterized juvenile chum salmon diet. A pteropod, Limacina sp., was an important prey for juvenile pink and sockeye salmon. Juvenile pink and sockeye salmon diets consisted of a wider variety of prey than those of chum salmon; they also had a higher prey overlap with each other than with chum salmon. The three species showed similar trends in selectivity in Prince William Sound and in shelf waters. These results suggest that there is a higher probability of competition between juvenile pink and sockeye salmon than between either juvenile pink or sockeye salmon and chum salmon.
    • Price credit and price risk simulation for Alaska natural gas pipleline project

      Cao, Yue (2003-05)
      This work describes the price risk involved in developing an Alaska Natural Gas Pipeline. Three alternatives were developed. They are an ALCAN Only 4.5 Bcf/day case, a Y-line case, and an ALCAN Only 5.5 Bcf/day case. The simulation result supports the conclusion that the ALCAN Only 4.5 Bcf/day case would be the most feasible and flexible choice for the long-run gas development with less commodity risk. Also, the price credit simulation was run based on the EIA natural gas price forecast. It shows how a Federal Tax Credit helps to reduce price risk making this marginal project more acceptable for participating oil companies. However it might not be revenue neutral for the Federal Government. The risk-assessment model was constructed in the Excel spreadsheet with a commercially purchased add-in feature (@RISK by Palisade Corp.) that performed the Monte Carlo simulation and the probabilistic outcomes. It was designed to be a dynamic tool that could estimate production performance with associated costs, and product prices to Yield an economic analysis. The model was specifically designed for the Alaska Natural Gas Pipeline. This work could be useful for government, companies, and any individual, who is currently involved with the Alaska Natural Gas Act.
    • Primary afferent projections in a diver, the muskrat

      Delisa, Susan Manette; Ebbesson, S. O. E. (1989)
      In a preliminary search for primary afferent connections involved in the diving response, cutaneous afferents from the nose were traced in muskrats and compared with those in rats, and with projections from the soft palate, posterior pharynx and larynx. Horseradish peroxidase (HRP) was injected into the skin or mucosa, under anesthesia. After 48 h survival, the deeply anesthetized animal was transcardially perfused and the brain was frozen and sectioned transversely in a cryostat. The sections were reacted for HRP according to standard techniques, using tetramethylbenzidine; alternate sections were Nissl stained. HRP-labeled structures were mapped using darkfield photomicrographs and camera lucida drawings. Cutaneous afferents from the nose in the muskrat project densely to layers I-II of the ventral and dorsolateral parts of the caudal subnucleus of the spinal trigeminal nucleus (Sp5C) and sparsely to layers V-VI of Sp5C, sparsely to the ventromedial part of the interpolar subnucleus of the spinal trigeminal nucleus (Sp5I), moderately to the oral subnucleus of the spinal trigeminal nucleus (Sp5O)--particularly the dorsomedial part, possibly overlapping with the nucleus of the solitary tract, and with processes of labeled cells of other lateral facial nucleus extending into ventromedial Sp5O,--moderately to the principal trigeminal nucleus (Pr5); and to the paratrigeminal nucleus (Pa5). Projections in the rat were the same, except that little or no labeling of layers V-VI of Sp5C, dorsomedial Sp5O, or Pa5 was present. Projections from the soft palate to layers I-II of rostral Sp5C, Sp5O, Sp5I, and Pr5 were similar to those from the nose in the muskrat. Heavy projections from the soft palate, and less dense projections from the posterior pharynx and larynx, to Pa5 also were found. Those regions receiving dense projections from the nose, overlapping projections from the various sites, and more highly developed projections from the nose in the muskrat than in the rat, are of particular interest for further investigation of the neural substrate underlying the diving response. The projections traced from the nose correspond particularly with nociceptive and thermoreceptive projections, which suggests that thermoafferent function may be involved in the elicitation of the diving response.
    • Primary production and nutrient dynamics of the southeastern Bering Sea shelf

      Rho, TaeKeun (2004-05)
      Understanding the relationships between the distributions of organisms and oceanographic conditions was one of the major goals of the Southeastern Bering Sea Carrying Capacity (SEBSCC) study. As a part of SEBSCC, this study focused on the response of nutrients and primary production to the variations of physical conditions, the general distribution of primary production, and the dynamics of phytoplankton growth, and nutrient utilization over the middle shelf and shelf break regions. The concentration of nutrients and primary productivity were measured over the shelf during 1997-1999. Shipboard nutrient and iron addition experiments were conducted over the middle shelf and shelf break region of the southeastern Bering Sea shelf during 2000-2001. The variations in physical conditions strongly affected the distribution of nutrients in the surface euphotic layer as well as in the deep layer. The offshore transport of the middle shelf water at mid-depth over the outer shelf may playa very important role in the export of materials, including regenerated iron, from the middle shelf to the shelf break. There were large seasonal and spatial variations in the development of the spring phytoplankton bloom due to the strength of upwelling and the slope of the front at the shelf break. However, annual primary production, estimated by combining carbon uptake data of the PROBES study and this study, were similar over the inner (133 g C m⁻² y⁻¹), middle (144 g C m⁻² y⁻¹) and outer (138 g C m⁻² y⁻¹) shelves and the shelfbreak (143 g C m⁻² y⁻¹). Nutrient addition studies showed that nitrogen availability was essential to continuous phytoplankton growth during summer, and that the interaction between ammonium and nitrate may play an important role in the dynamics of nutrient utilization. The iron addition study suggested that lack of iron did not affect the growth of phytoplankton over the middle shelf, but slightly suppressed growth at the outside edge of the shelf break region.
    • Principal stress orientations inferred from inversion of focal mechanism data in Hawaii and Iran

      Gillard, Dominique Gerard; Wyss, Max (1993)
      Fault plane solutions were inverted to estimate stress tensor directions in Hawaii and Iran. These directions were compared to the seismically released strain tensor obtained by summing the moment tensors of the same earthquakes. Attempts were made to determine which of the nodal planes was the fault plane. Regional seismotectonic models were constructed based on these results. The seismotectonic model for west Hawaii explains the seaward motion of the upper crust along a near-horizontal plane under a near-vertical greatest principal stress. The focal mechanism of the 1951 M = 6.9 Kona earthquake in west Hawaii was modeled as a decollement based on a synthesis of teleseismic body waves using a new method designed for sparse data sets. In southeast Hawaii, a single stress tensor orientation is compatible with a complex mixture of decollement, reverse, and normal faults. However, the stress field varies as a function of space and time. The differences between stress and strain orientations are caused by rotations of stress or strain directions, respectively, while the other remains constant. A rotation of the greatest principal stress in 1979 suggests magma movements within the aseismic part of Kilauea's southeast rift zone. Strain directions rotate due to the shifting of seismic activity from one fault to another in a volume of diverse faulting. These results show that the decollement plane at 10 km depth is weak and can slip in response to greatest principal stresses oriented near-perpendicular, sub-parallel or at 45$\sp\circ$ to it. In Iran, stress directions, as estimated from major earthquakes, are homogeneous over areas several hundred kilometers long and mostly coincide with strain directions, suggesting that the strength of the crust is uniform. The quality of the stress inversion results, measured by the size of the average misfit, is similar in Hawaii and Iran, although the dimensions of the study areas vary from tens to several hundreds of kilometers, and the magnitudes of the earthquakes from M = 3.5 $\pm$ 0.5 to M = 6 $\pm$ 0.5, respectively. Average misfits between 2$\sp\circ$ and 6$\sp\circ$ were obtained in both studies and are interpreted as characteristic of crustal volumes with homogeneous stress fields.
    • Probabilistic decline curve analysis in unconventional reservoirs using Bayesian and approximate Bayesian inference

      Korde, Anand A.; Awoleke, Obadare; Goddard, Scott; Dandekar, Abhijit (2019-08)
      In this work, a probabilistic methodology for Decline Curve Analysis (DCA) in unconventional reservoirs is presented using a combination of Bayesian statistical methods and deterministic models. Accurate reserve estimation and uncertainty quantification are the primary objectives of this study. The Bayesian inferencing techniques described in this work utilizes three sampling mechanisms, namely the Gibbs Sampling (implemented in OpenBUGS), the Metropolis Algorithm, and Approximate Bayesian Computation (ABC) to sample parameter values from their posterior distributions. These different sampling mechanisms are applied in conjunction with DCA models like Arps, Power Law Exponential (PLE), Stretched Exponential Production Decline (SEPD), Duong and Logistic Growth Analysis (LGA) to estimate prediction intervals. Production is forecasted, and uncertainty bounds are established using these prediction intervals. A complete workflow and the summary steps for each of the sampling techniques are provided to permit readers to replicate results. To examine the reliability, the methodology was tested over 74 oil and gas wells located in the three main sub plays of the Permian Basin, namely, the Delaware play, the Central Basin Platform, and the Midland play. Results show that the examined DCA-Bayesian models are successful in providing a high coverage rate, low production prediction errors and narrow uncertainty bounds for the production history data sets. The methodology was also successfully applied to unconventional reservoirs with as low as 6 months of available production history. Depending on the amount of production history available, the combined deterministic-stochastic model that provides the best fit can vary. It is therefore recommended that all possible combinations of the deterministic and stochastic models be applied to the available production history data. This is in order to obtain more confidence in the conclusions related to the reserve estimates and uncertainty bounds. The novelty of this methodology relies in using multiple combinations of DCA-Bayesian models to achieve accurate reserve estimates and narrow uncertainty bounds. The paper can help assess shale plays as most of the shale plays are in the early stages of production when the reserve estimations are carried out.
    • The problem with waking

      Reid, Steven John (2002-05)
      'The problem with waking' investigates the human struggle of coming to an awareness of self and the self's place among those who make up key relationships throughout life. The emphasis of the text is on locating moments in which the human essence is revealed against a variety of landscapes including forests, lakeshores, ice rinks, urban streets, and an international array of bars, from Chinese nightclubs to Alaskan pubs. Within the poems there is always an awareness of the poem on the page, on striking a visual balance in stanza length and white space. Line lengths are determined fundamentally on the belief that the strength of a poem is based on the creation and resolution of tensions and on a sensitivity to sound. Within the landscapes, representative moments are sought out and made lyric. Simple actions, often fragments of larger events, take on microcosmic, even mythical importance.
    • The process of founding Fairbanks Baptist Bible College: a case study

      Loriot, Cliff R. (2006-08)
      The purpose of this study was to compare the founding of Fairbanks Baptist Bible College with a procedure I later developed from various sources (Alaska Commission on Postsecondary Education [ACPE], "Regulations," 2000; "Statutes," 2000; Association of Governing Boards of Universities and Colleges [AGBUC], 2000; Cedarholm, 1988; Fadel, 1971; Fisher, 1983; Gribble, 1998; Halm and Hiatt, 1987; Ingram, 2003; Schindlbeck, 1969; Stark and Lattuca, 1997). The comparison shows that we omitted some important steps in establishing the college. Based on the previous sources, the results of the study, and Thornton's (1966) procedure, I developed a recommended process describing the responsibilities of four successive groups: the founders, the Board, the president, and the college. I concluded with some implications for future study.
    • Processes controlling nitrogen release and turnover in Arctic tundra

      Kielland, Knut; Chapin, F. Stuart III (1990)
      This thesis provides data on nitrogen cycling among communities representative of the major vegetation types in arctic Alaska. Through field studies, I examined the pattern of nitrogen dynamics in four tundra ecosystems (dry lichen heath, wet meadow, tussock tundra, and deciduous shrub tundra) of contrasting structure and productivity near Toolik Lake, Alaska. In addition, through field and laboratory experiments, I sought to identify the major controls over nitrogen release and turnover in these nitrogen-limited systems. These ecosystems, representing extremes of productivity in arctic Alaska, show order-of-magnitude differences in biomass and net primary productivity, and likewise, exhibit order-of-magnitude differences in net nitrogen mineralization and nitrogen turnover. Decomposition, soil respiration, net nitrogen mineralization, and the turnover of soil inorganic nitrogen were all highly correlated with net primary production. These results show that nutrient availability, in particular nitrogen availability, is a major control over tundra ecosystem function. Soil pools of organic nitrogen are large, whereas the pools of inorganic nitrogen are small, and the net rate of nitrogen mineralization in situ is low. Thus, nitrogen mineralization represents a major control point in the nitrogen cycle. Net nitrogen mineralization is relatively insensitive to changes in soil temperature, but highly responsive to changes in available soil carbon and nitrogen. Thus, the effect of organic matter quality on microbial activity is a more important control of nitrogen release than is the direct effect of temperature. Free amino acids constitute a larger proportion of extractable soil nitrogen than do ammonium and nitrate. Tundra species have the capacity to absorb some amino acids directly at rates comparable to ammonium absorption. These experimental results contrast with the widely held assumption that mineral nitrogen is the only form of nitrogen available to plants. I conclude that we must examine the behavior of both inorganic and organic soil nitrogen in order to adequately understand nitrogen cycling in tundra soils and the functioning of arctic ecosystems.
    • Processes controlling radon-222 and radium-226 on the southeastern Bering Sea shelf

      Glover, David M. (1985-12)
      An investigation was made into the use of radon-222 and radium-226 as tracers of air-sea gas exchange, water column mixing and sediment-water exchange on the southeastern Bering Sea shelf. Further more, a two-dimensional model was developed to unity these three processes into a coherent picture of radon-222 flux out of the sediments, through the water column and into the atmosphere. The best time period to average wind speeds when regressing them against gas transfer coefficients was found to be 3.3 days by a linear regression optimization, approximately the synoptic time scale of storms in the southeastern Bering Sea. A statistically significant relationship between averaged wind speed and transfer coefficients was found at the 80% confidence level. Gas transfer coefficients were found to tie obscured in shallow waters by radon flux from the sediments. Two-dimensional mixing in these continental shelf waters rendered the traditional one-dimensional vertical mixing model of excess radon-222 unable to obtain reliable vertical eddy ditfusivities. Exchange across the sediment-water interface was calculated from the deficiency of radon-222 measured in sediment cores, the standing crop of excess radon-222 in the overlying water column and the radon-222 production rate of sediment surface grab samples. The flux of radon-222 out of the sediments was found to increase in the onshore direction. Biological irrigation appears to be the primary exchange mechanism between the sediment and water column s on this shelf. Distributions in the water column show fine structure reported previously as well as biological removal of radium-226. A chi-square hypersurface search found the optimal horizontal and vertical eddy diffusivities that explained the two-dimensional distribution of radon-222 provided from a kriging estimation exercise on the data measured in this study. This model was essentially a hybrid of a least squares surface fit and a numerical integration of the governing differential equation of radon-222. When considered as a two-dimensional system in the cross-shelf direction, the rates of gas exchange, water column mixing and sediment-water exchange agree with each other to an acceptable degree.
    • Processes Controlling Radon-222 And Radium-226 On The Southeastern Bering Sea Shelf (Chemical Oceanography, Two-Dimensional Model, Continental, Gas-Exchange, Sediment Flux)

      Glover, David Mark (1985)
      An investigation was made into the use of ('222)Rn and ('226)Ra as tracers of air-sea gas exchange, water column mixing and sediment-water exchange on the southeastern Bering Sea shelf. Furthermore, a two-dimensional model was developed to unify these three processes into a coherent picture of ('222)Rn flux out of the sediments, through the water column and into the atmosphere. The best time period to average wind speeds when regressing them against gas transfer coefficients was found to be 3.3 days by a linear regression optimization, approximately the synoptic time scale of storms in the southeastern Bering Sea. A statistically significant relationship between averaged wind speed and transfer coefficients was found at the 80% confidence level. Gas transfer coefficients were found to be obscured in shallow waters by radon flux from the sediments. Two-dimensional mixing in these continental shelf waters rendered the traditional one-dimensional vertical mixing model of excess ('222)Rn unable to obtain reliable vertical eddy diffusivities. Exchange across the sediment-water interface was calculated from the deficiency of ('222)Rn measured in sediment cores, the standing crop of excess ('222)Rn in the overlying water column and the ('222)Rn production rate of sediment surface grab samples. The flux of radon out of the sediments was found to increase in the onshore direction. Biological irrigation appears to be the primary exchange mechanism between the sediment and water columns on this shelf. Distributions in the water column show finestructure reported previously as well as biological removal of ('226)Ra. A (chi)('2) hypersurface search found the optimal horizontal and vertical eddy diffusivities that explained the two-dimensional distribution of ('222)Rn provided from a kriging estimation exercise on the data measured in this study. This model was essentially a hybrid of a least squares surface fit and a numerical integration of the governing differential equation of ('222)Rn. When considered as a two-dimensional system in the cross-shelf direction, the rates of gas exchange, water column mixing and sediment-water exchange agree with each other to an acceptable degree.