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Sample records for alaskan wet sedge

  1. Effects of increased nutrients and warming on CO{sub 2} exchanges in Alaskan wet sedge tundras: Mechanism of response

    SciTech Connect

    Johnson, L.C.; Shaver, G.R.; Cades, D.C.

    1995-06-01

    We measured ecosystem- and leaf-level CO{sub 2} exchanges in Alaskan wet sedge tundra that had been warmed or fertilized for 6 years. Gross ecosystem photosynthesis (GEP), both diurnally and seasonally, was nearly double in N+P fertilizer additions. With N+P additions, GEP greatly exceeded ecosystem respiration, thereby increasing ecosystem C storage. Warming for 6 years (in a field greenhouse) had little effect on GEP, ecosystem respiration, or ecosystem C storage compared to controls.(Controls stored {approximately}90 gC m{sup -2} season{sup -1}.) In the N+P additions, higher canopy photosynthetic rates (P{sub max}) under saturating light conditions accounted for the higher GEP; under low light, GEP was similar among treatments. The increased canopy P{sub max} with N+P additions was due more to increased leaf mass than to increased photosynthesis per unit leaf area. Ecosystem respiration (plant plus microbial) strongly increased in response to greater nutrient availability. This increase was due to a stimulation of plant respiration (mostly aboveground) because the microbial component of the gaseous CO{sub 2} flux was small and unresponsive to treatments. In summary, ecosystem response to increased nutrients appears to be primarily dominated by aboveground plant response.

  2. Plant carbon-nutrient interactions control CO{sub 2} exchange in Alaskan wet sedge tundra ecosystems

    SciTech Connect

    Johnson, L.C.; Shaver, G.R.; Cades, D.H.; Rastetter, E.; Nadelhoffer, K.; Giblin, A.; Laundre, J.; Stanley, A.

    2000-02-01

    The authors explored the long-term (8-yr) effects of separate field manipulations of temperature and nutrient availability on carbon balance in wet sedge tundra near the Arctic Long Term Ecological Research (LTER) site at Toolik Lake, Alaska. Their goals were (1) to assess the relative importance of chronic warming (with field greenhouses) and increased N and P availability (by fertilization) in controlling gross ecosystem photosynthesis, ecosystem respiration, and ultimately ecosystem C balance; and (2) to attempt to partition ecosystem responses to these treatments between plant and soil contributions. The authors present results of the effects of these manipulations on whole-system CO{sub 2} exchange over seasonal and duel cycles, and on nonrhizosphere soil microbial respiration using in situ soil incubations.

  3. Contrasting radiation and soil heat fluxes in Arctic shrub and wet sedge tundra

    NASA Astrophysics Data System (ADS)

    Juszak, Inge; Eugster, Werner; Heijmans, Monique M. P. D.; Schaepman-Strub, Gabriela

    2016-07-01

    Vegetation changes, such as shrub encroachment and wetland expansion, have been observed in many Arctic tundra regions. These changes feed back to permafrost and climate. Permafrost can be protected by soil shading through vegetation as it reduces the amount of solar energy available for thawing. Regional climate can be affected by a reduction in surface albedo as more energy is available for atmospheric and soil heating. Here, we compared the shortwave radiation budget of two common Arctic tundra vegetation types dominated by dwarf shrubs (Betula nana) and wet sedges (Eriophorum angustifolium) in North-East Siberia. We measured time series of the shortwave and longwave radiation budget above the canopy and transmitted radiation below the canopy. Additionally, we quantified soil temperature and heat flux as well as active layer thickness. The mean growing season albedo of dwarf shrubs was 0.15 ± 0.01, for sedges it was higher (0.17 ± 0.02). Dwarf shrub transmittance was 0.36 ± 0.07 on average, and sedge transmittance was 0.28 ± 0.08. The standing dead leaves contributed strongly to the soil shading of wet sedges. Despite a lower albedo and less soil shading, the soil below dwarf shrubs conducted less heat resulting in a 17 cm shallower active layer as compared to sedges. This result was supported by additional, spatially distributed measurements of both vegetation types. Clouds were a major influencing factor for albedo and transmittance, particularly in sedge vegetation. Cloud cover reduced the albedo by 0.01 in dwarf shrubs and by 0.03 in sedges, while transmittance was increased by 0.08 and 0.10 in dwarf shrubs and sedges, respectively. Our results suggest that the observed deeper active layer below wet sedges is not primarily a result of the summer canopy radiation budget. Soil properties, such as soil albedo, moisture, and thermal conductivity, may be more influential, at least in our comparison between dwarf shrub vegetation on relatively dry patches and

  4. AmeriFlux US-ICs Imnavait Creek Watershed Wet Sedge Tundra

    SciTech Connect

    Bret-Harte, Syndonia; Euskirchen, Eugenie; Shaver, Gaius

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-ICs Imnavait Creek Watershed Wet Sedge Tundra. Site Description - The Imnavait Creek Watershed Wet Sedge Tundra (Fen Station) is located near Imnavait Creek in Alaska, north of the Brooks Range in the Kuparuk basin near Lake Toolik and the Toolik Field Station. The Kuparuk River has its headwaters in the Brooks Range and drains through northern Alaska into the Arctic Ocean. Within these headwaters lies the Imnavait basin at an average elevation of 930 m. Water tracks run down the hill in parallel zones with a spacing of approximately 10 m. The Fen Station was deployed at the end of Summer 2007.

  5. The temperature response of methane emission in Arctic wet sedge tundra

    NASA Astrophysics Data System (ADS)

    Lim, Edward; Zona, Donatella

    2015-04-01

    Since the last glacial maximum Arctic tundra soils have acted as an important carbon sink, having accumulated carbon under cold, anaerobic conditions (Zona et al. 2009). Several studies indicate that recent climate warming has altered this balance, with the Arctic tundra now posited to be a significant annual source of atmospheric methane (CH4) (McGuire et al. 2012). Nonetheless, the response of Arctic tundra CH4 fluxes to continued climate warming remains uncertain. Laboratory and field studies indicate that CH4 fluxes are temperature sensitive, thus accurate calculation of the temperature sensitivity is vital for the prediction of future CH4 emission. For this, the increase in reaction rate over a 10°C range (Q10) is frequently used, with single fixed Q10 values (between 2 and 4) commonly incorporated into climate-carbon cycle models. However, the temperature sensitivity of CH4 emission can vary considerably depending on factors such as vegetation composition, water table and season. This promotes the use of spatially and seasonally variable Q10 values for accurate CH4 flux estimation under different future climate change scenarios. This study investigates the temperature sensitivity (Q10) of Arctic tundra methane fluxes, using an extensive number of soil cores (48) extracted from wet sedge polygonal tundra (Barrow Experimental Observatory, Alaska). 'Wet' and 'dry' cores were taken from the centre and raised perimeter of ice-wedge polygons, where the water tables are 0cm and -15cm respectively. Cores were incubated in two controlled environment chambers (University of Sheffield, UK) for 12 weeks under different thaw depth treatments (control and control + 6.8cm), water tables (surface and -15cm), and CO2 concentrations (400ppm and 850ppm) in a multifactorial manner. Chamber temperature was gradually increased from -5°C to 20°C, then gradually decreased to -5°C, with each temperature stage lasting one week. Average CH4 fluxes from 'dry' cores were consistently

  6. Plant growth form more important than temperature in controlling CH{sub 4} flux in Alaskan tundra communities

    SciTech Connect

    Verville, J.H.; Chapin, F.S. III.; Hobbie, S.E.

    1995-09-01

    We conducted species removals, vegetation and soil transplants, and air temperature manipulations in Alaskan wet meadow and upland tussock tundra communities to determine the relative importance of vegetation type and environmental variables in controlling CH{sub 4} flux. Removal of sedges in the wet meadow community significantly decreased CH{sub 4} flux, while moss removal had no significant effects on emissions. At 15 cm depth, pore water CH{sub 4} concentrations were higher in sedge removals, relative to control plots, suggesting that sedges contribute to CH{sub 4} emissions by transporting CH{sub 4} from anaerobic soil to the atmosphere, rather than by promoting methanogenesis. In reciprocal ecosystem transplants between the wet meadow and upland tussock tundra communities, CH{sub 4} flux was higher in the wet meadow site, but was unrelated to transplant origin. Soil temperature, thaw depth, and water table depth were correlated with CH{sub 4} flux, but their relative importance on a local level varied throughout the season. Plastic greenhouses placed over the wet meadow species removal plots increased soil moisture and air and soil temperatures, but did not affect CH{sub 4} flux. These results suggest that future changes in CH{sub 4} flux in response to climatic change will be more strongly mediated by large-scale changes in soil moisture and vegetation than by direct temperature effects on CH{sub 4} emissions.

  7. Mycorrhiza in sedges--an overview.

    PubMed

    Muthukumar, T; Udaiyan, K; Shanmughavel, P

    2004-04-01

    Most terrestrial plants associate with root-colonising mycorrhizal fungi, which improve the fitness of both the fungal and plant associates. However, exceptions exist both between and within plant families failing to associate with mycorrhizal fungi or in the incidence and the extent of mycotrophy, which may vary greatly. Sedges are important pioneers of disturbed habitats and often dominate vegetations like wetlands, and arctic and alpine vegetations, in which the mycorrhizal inoculum in the soil is often low or absent. In the past, sedges were often designated as non-mycorrhizal, though limited reports indicated the presence of mycorrhiza in certain species. However, studies since 1987 indicate widespread occurrence of mycorrhiza in sedges. Based on these studies, the family Cyperaceae is no longer a non-mycorrhizal family, but the mycorrhizal status of its members is greatly influenced by environmental conditions. Further, sedges appear to have several morphological adaptations to thrive in the absence of mycorrhizal association. Though mycorrhizal associations have been noted in many sedge species, the ecological role of this association is not well documented and no clear generalisation can be drawn. Similarly, the role of mycorrhizal fungi on sedge growth and nutrient uptake or non-nutritional benefits has yet to be fully ascertained. This paper reviews the current information available on the incidence of mycorrhiza in sedges and the possible reasons for low mycotrophy observed in this family.

  8. Alaskan Voices.

    ERIC Educational Resources Information Center

    Achatz, Mary, Ed.; Caldera, Debra, Ed.; Saylor, Brian; DeGross, Denny

    This paper examines the attitudes of adults and teenagers in 10 predominantly rural Alaskan communities toward their own health and well-being and that of children and families in their community. The communities were located across the state and ranged in size from populations of under 900 to over 50,000. The proportion of Alaska Natives in the…

  9. Gypsy Sedge or Just Another Non-native Invasive Weedy Sedge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-native weeds present a huge threat to agricultural and non-agricultural lands throughout the U.S.A. Blue sedge (Carex breviculmis R. Br.: Cyperaceae) is a non-native invasive weed discovered in North America in 2007. The sedge is native of Asia, Australia, and the Indian Subcontinent where it ...

  10. Gypsy Sedge or Just Another Non-Native Invasive Weedy Sedge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-native weeds present a huge threat to agricultural and non-agricultural lands throughout the U.S.A. Blue sedge (Carex breviculmis R. Br.: Cyperaceae) is a non-native invasive weed discovered in North America in 2007. The sedge is native of Asia, Australia, and the Indian Subsontinent where it ...

  11. Alder Expansion as a Coastal Warming Signal - Linking Coastal Alaskan Carbon to Vegetation Change with Climate

    NASA Astrophysics Data System (ADS)

    Peteet, D. M.; Nichols, J. E.; Moy, C. M.; McGeachy, A.

    2014-12-01

    Corser Bog (60.5296364oN, 145.453858oW), 21 km east of Cordova, AK is a sphagnum-dominated peatland 42 m asl. adjacent to Sheridan Glacier and the Copper River Delta. Deglaciation at 11.5 ka began with shallow pond deposition, reflecting regional warmth with the pioneers Alnus crispa subsp. sinuata, Salix, and ferns colonizing the fresh, mineral soils on the landscape. Continued early Holocene warming/melting of glaciers led to the foundation species Alnus dominance and peatland formation, surrounded by shrubs such as Rubus spectabilis, Sambucus racemosa, and wetland species such as Myrica gale and Potentilla palustris. As Sphagnum peat accumulated, the highest rates of carbon accumulation for a few centuries are represented at 50 g/m2/a, similar to short-term very high rates in the early Holocene throughout the circumboreal region but varying within the early Holocene due to development of local wet, bryophytic environments. A shift to sedge peat regionally along the South-Central Alaskan coast 7.6 - 3.7 ka is paralleled by a more evaporative, drier climate with Rhododendron groenlandicum presence, lower carbon accumulation (13 g/m2/a), and minimal macrofossil preservation, which is paralleled regionally in coastal muskegs both to the northwest and southeast and by a hiatus in a nearby lake record. A cooler, moister climate is evident in Corser Bog with the shift to Sphagnum peat at 3.7 ka, regional shifts from sedge to Sphagnum peat throughout the entire coastline from Yakutat to Girdwood, AK and the demonstration of glacial advances in the region. Alnus pollen markedly increases to 60% in the uppermost sample, indicative of a major signal for glacial recession in this region.

  12. Chasing Nutrients with an Arctic Sedge

    NASA Astrophysics Data System (ADS)

    Iverson, S. L.; Schimel, J.

    2013-12-01

    Climate change has put the Arctic into a state of flux. Understanding the effects an altered climate will have on vegetation and nutrient cycling requires more knowledge of the key plant and soil functions of major arctic ecosystems. One of these ecosystems, moist acidic tussock tundra, is dominated by a single plant species, the tussock-forming sedge Eriophorum vaginatum. This plant has unusual underground biomass: long, fast-growing, non-branching, non-mycorrhizal roots. In contrast to many other plants in nutrient-limiting environments, this sedge is highly successful without maximizing its root surface area to volume ratio. The benefits of this growth strategy to the plants and its effects on the accompanying soil-microbe-plant relationships are not fully understood. One possibility is that the roots may help the plant take advantage of nutrients released into the active layer of soil as it thaws in the spring. The roots may also stimulate microbial activity, increasing nutrient turnover and availability. A study was undertaken to explore the nitrogen (N) and carbon (C) dynamics in these plants, as well as the microbial populations associated with active E. vaginatum roots. Intact tussock microcosms (plant and accompanying soil) were removed from the tundra and cultivated in transparent boxes. Half the plants were kept in light to encourage photosynthesis (and thus greater plant activity), while the other half was kept in the dark to inhibit it. Using a 15N isotopic tracer injected at the extremity of root penetration into the soil, the N uptake capacity of E. vaginatum roots at depth was explored. This uptake capacity is compared to measures of plant activity, microbial activity, and soil solution chemistry in order to paint a clearer picture of the role of E. vaginatum in the soil ecosystem.

  13. Silicified structures affect leaf optical properties in grasses and sedge.

    PubMed

    Klančnik, Katja; Vogel-Mikuš, Katarina; Gaberščik, Alenka

    2014-01-01

    Silicon (Si) is an important structural element that can accumulate at high concentrations in grasses and sedges, and therefore Si structures might affect the optical properties of the leaves. To better understand the role of Si in light/leaf interactions in species rich in Si, we examined the total Si and silica phytoliths, the biochemical and morphological leaf properties, and the reflectance and transmittance spectra in grasses (Phragmites australis, Phalaris arundinacea, Molinia caerulea, Deschampsia cespitosa) and sedge (Carex elata). We show that these grasses contain >1% phytoliths per dry mass, while the sedge contains only 0.4%. The data reveal the variable leaf structures of these species and significant differences in the amount of Si and phytoliths between developing and mature leaves within each species and between grasses and sedge, with little difference seen among the grass species. Redundancy analysis shows the significant roles of the different near-surface silicified leaf structures (e.g., prickle hairs, cuticle, epidermis), phytoliths and Si contents, which explain the majority of the reflectance and transmittance spectra variability. The amount of explained variance differs between mature and developing leaves. The transmittance spectra are also significantly affected by chlorophyll a content and calcium levels in the leaf tissue.

  14. Women and Minorities in Alaskan Aviation. Alaskan Equity Publication.

    ERIC Educational Resources Information Center

    Dordan, Mary Lou; Nicholson, Deborah

    This resource guide tells the story of Alaskan women and minority aviators and those in aviation-related businesses, from the early 20th century to the present. Developed for secondary students but also suitable for younger students, the guide combines six accounts of Alaskan women and minority aviators with classroom activities centered around…

  15. How sedge meadow soils, microtopography, and vegetation respond to sedimentation

    USGS Publications Warehouse

    Werner, K.J.; Zedler, Joy B.

    2002-01-01

    The expansion of urban and agricultural activities in watersheds of the Midwestern USA facilitates the conversion of species-rich sedge meadows to stands of Phalaris arundinacea and Typha spp. We document the role of sediment accumulation in this process based on field surveys of three sedge meadows dominated by Carex stricta, their adjacent Phalaris or Typha stands, and transitions from Carex to these invasive species. The complex microtopography of Carex tussocks facilitates the occurrence of other native species. Tussock surface area and species richness were positively correlated in two marshes (r2 = 0.57 and 0.41); on average, a 33-cm-tall tussock supported 7.6 species. Phalaris also grew in tussock form in wetter areas but did not support native species. We found an average of 10.5 Carex tussocks per 10-m transect, but only 3.5 Phalaris tussocks. Microtopographic relief, determined with a high-precision GPS, measured 11% greater in Carex meadows than Phalaris stands. Inflowing sediments reduced microtopographic variation and surface area for native species. We calculated a loss of one species per 1000 cm2 of lost tussock surface area, and loss of 1.2 species for every 10-cm addition of sediment over the sedge meadow surface. Alluvium overlying the sedge meadow soil had a smaller proportion of organic matter content and higher dry bulk density than the buried histic materials. We conclude that sedimentation contributes to the loss of native species in remnant wetlands. ?? 2002, The Society of Wetland Scientists.

  16. Alaskan Commodities Irradiation Project

    SciTech Connect

    Zarling, J.P.; Swanson, R.B.; Logan, R.R.; Das, D.K.; Lewis, C.E.; Workman, W.G.; Tumeo, M.A.; Hok, C.I.; Birklid, C.A.; Bennett, F.L.

    1988-12-01

    The ninety-ninth US Congress commissioned a six-state food irradiation research and development program to evaluate the commercial potential of this technology. Hawaii, Washington, Iowa, Oklahoma and Florida as well as Alaska have participated in the national program; various food products including fishery products, red meats, tropical and citrus fruits and vegetables have been studied. The purpose of the Alaskan study was to review and evaluate those factors related to the technical and economic feasibility of an irradiator in Alaska. This options analysis study will serve as a basis for determining the state's further involvement in the development of food irradiation technology. 40 refs., 50 figs., 53 tabs.

  17. Increase in sedge biomass across a permafrost thaw gradient correlates to changes in the magnitude and isotopic composition of methane emissions

    NASA Astrophysics Data System (ADS)

    Werner, S. L.; Malhotra, A.; McCalley, C. K.; Varner, R. K.; Roulet, N. T.; Crill, P. M.

    2013-12-01

    Species transitions have been observed in northern latitudes in response to a warming climate. Sedge species in particular are becoming more abundant as permafrost thaws. These species are closely linked to increases in methane (CH4) emission, which has 23 times the global warming potential of carbon dioxide (CO2) and wetlands are a major natural source of emissions. Understanding how CH4emissions are associated with species changes during thaw is essential for estimating CH4 fluxes from discontinuous permafrost regions and for predicting the trajectory of CH4 emissions under future climate change. To understand the relationship between sedges and methane emissions, we measured methane fluxes and the isotopic composition of pore water CH4 and CO2 along a permafrost thaw gradient in Stordalen Mire, Abisko, Sweden. To determine the controls on CH4emission, we measured vegetation biomass, pH, soil temperature, active layer depth and species composition. Significant differences were found between different vegetation classes, with lowest fluxes of CH4 observed in the frozen palsa (0.73 × 4.41 mg m-2d-1), mid-range fluxes in Sphagnum sites (14.2 1 × 15.8 mg m-2d-1) and highest fluxes in the wet graminoid (165.4 × 136.6 mg m-2d-1). The best indicator of CH4 flux was biomass of sedge vegetation (e.g Eriophorum vaginatum and Carex spp.) (R2= 0.86 p= 0.001). In general, pore water CH4 increased with depth and was on average highest and most variable in the Carex spp. dominated sites compared to the mixed vegetation, Sphagnum and E. vaginatum dominated sites. The best predictor of below ground CH4 concentration was also sedge biomass (R2= 0.86 p= 0.01 at 30 cm). The variability and abundance of CH4 indicates differences in methane production rates depending on the presence of sedges. Patterns in del13C-CH4 suggest a shift from hydrogenotrophic production in Sphagnum dominated sites to increasing contributions from acetate fermentation in sedge-dominated sites. These

  18. An Alaskan legend

    USGS Publications Warehouse

    Mann, H.; Blodgett, R.B.

    2009-01-01

    Jack Lee is a prominent personality, an Alaskan individualist and a skeptic worthy of remembrance if for no other reason than being inextricably associated with the catastrophic Katmai eruption in 1912. Jack remains a provocative reminder of Alaska's pre-1958 drilling and was quite possibly the earliest observer (excepting natives and possibly Russians) of the oil seeps in the area now encompassed by the Becharof National Wildlife Refuge. His observation of the impressive live oil seeps in the Ugashik and Becharof Lakes area, and his subsequent involvement in the early drilling entirely consumed his future interests. He is a firm believer that individualism and suspicion are powerful tools when forced to reconsider alternatives to readily accepted interpretations of modern exploration results. His individualism and sometimes annoying, but thought-provoking skepticism remains useful in any field where clich??s provide safe guards from new concepts.

  19. Growth reproductive potential and control strategies for deeproot sedge (Cyperus entreianus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse, growth chamber, and field studies were conducted at Stoneville, MS in 2000-2008 to determine the growth rate, reproductive and overwintering potential, and control of deeproot sedge. In growth chamber studies, deeproot sedge growth rate (height) and plant dry weights were greatest for 2...

  20. Cattle Grazing and Its Long-term Effects on Sedge Meadows

    USGS Publications Warehouse

    Middleton, Beth

    2004-01-01

    Most people think that wetlands are temporary, that they fill in by natural processes, and eventually become dry land. Some of these outdated ideas have come from the way that this subject has been covered in introductory textbooks in schools (Gibson, 1996). From these texts, we learned incorrectly that over time a lake fills with sediment or organic matter to become a wetland, which dries out to support shrubs and trees, and eventually it is no longer a wetland (Middleton, 1999; Middleton and others, 2004). These old ideas of how vegetation changes (succession) are no longer accepted. Wetland succession should be thought of as a cycle, with natural disturbance driving the changes, depending on the needs of the species. Succession is not something that changes a wetland into something that is not a wetland (Egler, 1978; van der Valk, 1981; Middleton and others, 1991; Klinger, 1996; Middleton, 1999). As an example of how disturbance changes wetlands, I have studied sedge meadows that have become invaded by shrubs after cattle (Bos sp.) have grazed them, in the Lodi Marsh State Natural Area, Wisconsin. Cattle disturbances allowed shrubs to invade sedge meadows, but the cattle also grazed on the shrubs, which kept them small. After the cows were removed, the plant species changed in the sedge meadow from the original sedges (fig. 1), to sedges mixed with growing small shrubs, and eventually to tall shrubs with very small amounts of sedge, called ?shrub carr? (Middleton, 2002a). Even though there has been a succession of plant types, the meadows, which began as wetlands, have remained wetlands. The settlers originally found the sedge meadows to be open ?sedge? lands and not shrubby. The settlers cut the sedges by hand to feed the cattle. Whitetailed deer (Odocoileus virginianus), though probably not bison (Bison bison), grazed these sedge meadows (Middleton 2002a).

  1. Linkage among Vegetation, Microbes and Methanogenic Pathways in Alaskan Peatlands

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Sidelinger, W.; Shu, H.; Varner, R. K.; Hines, M. E.

    2014-12-01

    Northern wetlands are thought to account for one third of the naturally emitted CH4. However, methane production pathways in northern peatlands are poorly understood, yet are predicted to change in response to vegetation shifts due to warming. Previous studies noted that acetate conversion to methane (acetoclastic methanogenesis, AM) in northern wetlands is largely impeded and acetate accumulates, however AM tends to increase with minerotrophy. To understand methanogenic pathways and to provide linkage among pathways, we studied Alaskan wetlands in 2013 and 2014. In 2013, laboratory incubations were conducted in three peatlands representing trophic gradients from bogs to fens. During 2014, 37 different sites in Fairbanks and Anchorage were studied that represented wetlands with pH values from 3.5 to 5.5 and vegetation from primarily Sphagnum to sedges. Measurements in 2014 included vegetation composition, gases (CH4, CO2, H2, and CO), 13CH4 and 13CO2, volatile fatty acids, DOC, other electron acceptors. Further incubation studies are being conducted to decipher controls on decomposition pathways. Gene sequencing was used to characterize microbial community composition, and metagenomic and transcriptomics were conducted to describe community activity. Results showed that methanogenesis was higher in fens than bogs, but hydrogenotrophic methanogenesis (HM) was dominant at all sites. End product ratios showed that AM was occurring in fens, albeit slowly. Fermentation was an important end-point in decomposition and microbial syntrophy was weak. These data, regardless of trophic status, differed greatly from data obtained from temperate wetlands in which terminal respiratory processes were strong and C flow through syntrophy was important. Trophic status influenced C flow in the Alaskan sites, but terminal processes were weak and end product formation tended to end at primary fermentation, which dominated as the terminal step in decomposition.

  2. Nonuniform processes of chromosome evolution in sedges (Carex: Cyperaceae).

    PubMed

    Hipp, Andrew L

    2007-09-01

    Holocentric chromosomes-chromosomes that lack localized centromeres-occur in numerous unrelated clades of insects, flatworms, and angiosperms. Chromosome number changes in such organisms often result from fission and fusion events rather than polyploidy. In this study, I test the hypothesis that chromosome number evolves according to a uniform process in Carex section Ovales (Cyperaceae), the largest New World section of an angiosperm genus renowned for its chromosomal variability and species richness. I evaluate alternative models of chromosome evolution that allow for shifts in both stochastic and deterministic evolutionary processes and that quantify the rate of evolution and heritability/phylogenetic dependence of chromosome number. Estimates of Ornstein-Uhlenbeck model parameters and tree-scaling parameters in a generalized least squares framework demonstrate that (1) chromosome numbers evolve rapidly toward clade-specific stationary distributions that cannot be explained by constant variance (Brownian motion) evolutionary models, (2) chromosome evolution in the section is rapid and exhibits little phylogenetic inertia, and (3) explaining the phylogenetic pattern of chromosome numbers in the section entails inferring a shift in evolutionary dynamics at the root of a derived clade. The finding that chromosome evolution is not a uniform process in sedges provides a novel example of karyotypic orthoselection in an organism with holocentric chromosomes.

  3. Restoration potential of sedge meadows in hand-cultivated soybean fields in northeastern China

    USGS Publications Warehouse

    Wang, Guodong; Middleton, Beth; Jiang, Ming

    2013-01-01

    Sedge meadows can be difficult to restore from farmed fields if key structural dominants are missing from propagule banks. In hand-cultivated soybean fields in northeastern China, we asked if tussock-forming Carex and other wetland species were present as seed or asexual propagules. In the Sanjiang Plain, China, we compared the seed banks, vegetative propagules (below-ground) and standing vegetation of natural and restored sedge meadows, and hand-cultivated soybean fields in drained and flooded conditions. We found that important wetland species survived cultivation as seeds for some time (e.g. Calamogrostis angustifolia and Potamogeton crispus) and as field weeds (e.g. C. angustifolia and Phragmites australis). Key structural species were missing in these fields, for example, Carex meyeriana. We also observed that sedge meadows restored without planting or seeding lacked tussock-forming sedges. The structure of the seed bank was related to experimental water regime, and field environments of tussock height, thatch depth, and presence of burning as based on Nonmetric Multidimensional Scaling analysis. To re-establish the structure imposed by tussock sedges, specific technologies might be developed to encourage the development of tussocks in restored sedge meadows.

  4. Treatment of domestic wastewater by vertical flow constructed wetland planted with umbrella sedge and Vetiver grass.

    PubMed

    Kantawanichkul, Suwasa; Sattayapanich, Somsiri; van Dien, Frank

    2013-01-01

    The aim of this study was to investigate the efficiency of wastewater treatment by vertical flow constructed wetland systems under different hydraulic loading rates (HLR). The comparison of two types of plants, Cyperus alternifolius (Umbrella sedge) and Vetiveria zizanioides (Vetiver grass), was also conducted. In this study, six circular concrete tanks (diameter 0.8 m) were filled with fine sand and gravel to the depth of 1.23 m. Three tanks were planted with Umbrella sedge and the other three tanks were planted with Vetiver grass. Settled domestic wastewater from Chiang Mai University (chemical oxygen demand (COD), NH4(+)-N and suspended solids (SS) of 127.1, 27.4 and 29.5 mg/L on average, respectively) was intermittently applied for 45 min and rested for 3 h 15 min. The HLR of each tank was controlled at 20, 29 and 40 cm/d. It was found that the removal efficiency of the Umbrella sedge systems was higher than the Vetiver grass systems for every parameter, and the lowest HLR provided the maximum treatment efficiency. The removal efficiency of COD and nitrogen in terms of total Kjeldahl nitrogen (TKN) was 76 and 65% at 20 cm/d HLR for Umbrella sedge compared to only 67 and 56% for Vetiver grass. Nitrogen accumulation in plant biomass was also higher in Umbrella sedge than in Vetiver grass in every HLR. Umbrella sedge was thus proved to be a suitable constructed wetland plant in tropical climates.

  5. Ecological importance of sedges: a survey of the Australasian Cyperaceae genus Lepidosperma

    PubMed Central

    Barrett, Russell L.

    2013-01-01

    Background Sedges (Cyperaceae) form an important ecological component of many ecosystems around the world. Sword and rapier sedges (genus Lepidosperma) are common and widespread components of the southern Australian and New Zealand floras, also occurring in New Caledonia, West Papua, Borneo, Malaysia and southern China. Sedge ecology is seldom studied and no comprehensive review of sedge ecology exists. Lepidosperma is unusual in the Cyperaceae with the majority of species occurring in dryland habitats. Scope Extensive review of ecological literature and field observations shows Lepidosperma species to be important components of many ecosystems, often dominating understorey and sedge-rich communities. For the first time, a detailed ecological review of a Cyperaceae genus is presented. Conclusions Lepidosperma species are long-lived perennials with significant abundance and persistence in the landscape. Speciation patterns in the genus are of considerable interest due to complex biogeographical patterns and a high degree of habitat specificity. Potential benefits exist for medicinal products identified from several Lepidosperma species. Over 178 organisms, including 26 mammals, 42 birds, six reptiles, five amphibians, eight arachnids, 75 insects, three crustaceans and 13 fungi, are found to be dependent on, or making use of, Lepidosperma species. A significant relationship exists between Lepidosperma species and the moth genus Elachista. Implications for the conservation and ecology of both sedges and associated species are discussed. PMID:23378523

  6. Treatment of domestic wastewater by vertical flow constructed wetland planted with umbrella sedge and Vetiver grass.

    PubMed

    Kantawanichkul, Suwasa; Sattayapanich, Somsiri; van Dien, Frank

    2013-01-01

    The aim of this study was to investigate the efficiency of wastewater treatment by vertical flow constructed wetland systems under different hydraulic loading rates (HLR). The comparison of two types of plants, Cyperus alternifolius (Umbrella sedge) and Vetiveria zizanioides (Vetiver grass), was also conducted. In this study, six circular concrete tanks (diameter 0.8 m) were filled with fine sand and gravel to the depth of 1.23 m. Three tanks were planted with Umbrella sedge and the other three tanks were planted with Vetiver grass. Settled domestic wastewater from Chiang Mai University (chemical oxygen demand (COD), NH4(+)-N and suspended solids (SS) of 127.1, 27.4 and 29.5 mg/L on average, respectively) was intermittently applied for 45 min and rested for 3 h 15 min. The HLR of each tank was controlled at 20, 29 and 40 cm/d. It was found that the removal efficiency of the Umbrella sedge systems was higher than the Vetiver grass systems for every parameter, and the lowest HLR provided the maximum treatment efficiency. The removal efficiency of COD and nitrogen in terms of total Kjeldahl nitrogen (TKN) was 76 and 65% at 20 cm/d HLR for Umbrella sedge compared to only 67 and 56% for Vetiver grass. Nitrogen accumulation in plant biomass was also higher in Umbrella sedge than in Vetiver grass in every HLR. Umbrella sedge was thus proved to be a suitable constructed wetland plant in tropical climates. PMID:24056433

  7. Cattle grazing and its long-term effects on sedge meadows

    USGS Publications Warehouse

    Middleton, Beth

    2004-01-01

    Most people think that wetlands are temporary, that they fill in by natural processes, and eventually become dry land. Some of these outdated ideas have come from the way that this subject has been covered in introductory textbooks in schools (Gibson, 1996). From these texts, we learned incorrectly that over time a lake fills with sediment or organic matter to become a wetland, which dries out to support shrubs and trees, and eventually it is no longer a wetland (Middleton, 1999; Middleton and others, 2004). These old ideas of how vegetation changes (succession) are no longer accepted. Wetland succession should be thought of as a cycle, with natural disturbance driving the changes, depending on the needs of the species. Succession is not something that changes a wetland into something that is not a wetland (Egler, 1978; van der Valk, 1981; Middleton and others, 1991; Klinger, 1996; Middleton, 1999).As an example of how disturbance changes wetlands, I have studied sedge meadows that have become invaded by shrubs after cattle (Bos sp.) have grazed them, in the Lodi Marsh State Natural Area, Wisconsin. Cattle disturbances allowed shrubs to invade sedge meadows, but the cattle also grazed on the shrubs, which kept them small. After the cows were removed, the plant species changed in the sedge meadow from the original sedges (fig. 1), to sedges mixed with growing small shrubs, and eventually to tall shrubs with very small amounts of sedge, called “shrub carr” (Middleton, 2002a). Even though there has been a succession of plant types, the meadows, which began as wetlands, have remained wetlands. The settlers originally found the sedge meadows to be open “sedge” lands and not shrubby. The settlers cut the sedges by hand to feed the cattle. Whitetailed deer (Odocoileus virginianus), though probably not bison (Bison bison), grazed these sedge meadows (Middleton 2002a).Subsequent studies have explored methods to control invasive shrubs to restore the biodiversity of

  8. Controls on evapotranspiration at a subarctic sedge fen

    NASA Astrophysics Data System (ADS)

    Eaton, Andrea K.; Rouse, Wayne R.

    2001-12-01

    In this study, 10 years (1990-99) of summertime data collected at a representative sedge fen in the Hudson Bay Lowland (HBL) are used to investigate the energy and water balance dynamics of subarctic wetlands. The summertime climatic characteristics at the study site during the 10 year study period are also examined. It is shown that mean cumulative summertime precipitation Pavg for the study decade closely approximates the 30 year mean Pavg. However, the mean summertime air temperature Tavg for the study decade is 1 °C higher than the 30 year mean Tavg.To examine the energy and water balance dynamics at the study site, the variation in each of their respective components throughout the study decade is considered. Little variation is observed in cumulative summertime net radiation and cumulative summertime ground heat flux QGcum; however, substantial year-to-year variation is evident in cumulative summertime water deficit WDcum, cumulative summertime precipitation P

  9. C-isotope composition of fossil sedges and grasses

    NASA Astrophysics Data System (ADS)

    Kurschner, Wolfram M.

    2010-05-01

    C4 plants differ from C3 plants regarding their anatomy and their C-isotope composition. Both features can be used in the geological record to determine the presence of C4 plants. Yet, the evolution of the C4 pathway in the fossil record is enigmatic as palaeobotanical and geological evidence for C4 plants is sparse. The oldest structural evidence for Kranz anatomy has been found in Late Miocene permineralized grass leaf remains. But studies on the C-isotope composition of sedimentary organic matter indicate that abundant C4 biomass was present in N-America and Asia throughout the Miocene in expanding savannahs and grasslands. The success of C4 plants appears to be related also to an increasing seasonal aridity in the tropical climate belts and the co-evolution of grazers. However, C- isotope composition of palaeosols or vertebrate teeth only allows to estimate the abundance of C4 plant biomass in the vegetation or in the diet without further taxonomical specification which plant groups would have had C4 metabolism. In this contribution the first extensive C-isotope analysis of fossil seeds of sedges and a few grasses are presented. The age of the carpological material ranges from Late Eocene to Pliocene and was collected from several central European brown coal deposits. The 52 different taxa studied include several species of Carex, Cladiocarya, Eriopherum, Eleocharis, Scirpus, Sparganium. Most of them representing herbaceous elements of a (sub)tropical vegetation growing near the edge of a lake. The C-isotope composition of the fossil seeds varies between -30 and -23 o/oo indicating C3 photosynthesis. This first systematic inventory shows that C4 plants were absent in the European (sub)tropical brown coal forming wetland vegetation during the Tertiary. These preliminary data are in agreement with phylogenetic studies which predict the origin of C4 plants outside the European realm.

  10. Disjunct performance and distribution in the sedge Carex prasina.

    PubMed

    Flinn, Kathryn M; Waterway, Marcia J; Lechowicz, Martin J

    2010-05-01

    Efforts to understand species distributions and predict responses to environmental changes depend on specifying how the abiotic environment determines distributions. At landscape scales, it is critical to distinguish effects of environmental factors from other mechanisms such as competition and dispersal limitation. We examined how environmental factors affect the distribution and performance of the sedge Carex prasina across a 10-km(2) old-growth forest in southern Québec. We isolated the effects of soil characteristics by conducting a greenhouse experiment that assessed the performance of C. prasina on soils from a range of wetland habitats where it could potentially occur. This allowed us to compare how the species' performance and its distribution across the landscape relate to the same soil characteristics. In the experiment, the biomass and leaf chlorophyll content of C. prasina increased with increasing soil organic matter (OM). Across the landscape, however, the species' probability of occurrence and abundance decreased with increasing soil OM. C. prasina had similar biomass on soils from sites where it did and did not occur, but it had higher leaf chlorophyll content on soils from sites where it did not occur. We found no evidence that differential performance across environments determines the distribution of this species, as C. prasina tended to occur on soils where it showed reduced performance. Rather, other processes such as competition or dispersal limitation likely override any direct effects of the soil environment on distribution. Our results caution against the common assumption that the environments where a species tends to occur or be most abundant are the environments where it performs best. C. prasina presents a clear example of a species whose performance, at least along edaphic gradients, cannot explain its distribution. This example highlights the importance of distinguishing the relative roles of biotic and abiotic factors that shape

  11. New flat mite genera (Acari: Trombidiformes: Tenuipalpidae) associated with Australian sedges (Cyperaceae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two new genera, Gahniacarus and Cyperacarus, and four new species, G. gersonus, G. tuberculatus, C. naomae and C. foliatus, are described from native Australian sedge species in the genus Gahnia (Cyperaceae). Leg chaetotaxy is provided for all stages of each species. The importance of taxonomic ch...

  12. Hominins, sedges, and termites: new carbon isotope data from the Sterkfontein valley and Kruger National Park.

    PubMed

    Sponheimer, Matt; Lee-Thorp, Julia; de Ruiter, Darryl; Codron, Daryl; Codron, Jacqui; Baugh, Alexander T; Thackeray, Francis

    2005-03-01

    Stable carbon isotope analyses have shown that South African australopiths did not have exclusively frugivorous diets, but also consumed significant quantities of C4 foods such as grasses, sedges, or animals that ate these foods. Yet, these studies have had significant limitations. For example, hominin sample sizes were relatively small, leading some to question the veracity of the claim for australopith C4 consumption. In addition, it has been difficult to determine which C4 resources were actually utilized, which is at least partially due to a lack of stable isotope data on some purported australopith foods. Here we begin to address these lacunae by presenting carbon isotope data for 14 new hominin specimens, as well as for two potential C4 foods (termites and sedges). The new data confirm that non-C3 foods were heavily utilized by australopiths, making up about 40% and 35% of Australopithecus and Paranthropus diets respectively. Most termites in the savanna-woodland biome of the Kruger National Park, South Africa, have intermediate carbon isotope compositions indicating mixed C3/C4 diets. Only 28% of the sedges in Kruger were C4, and few if any had well-developed rhizomes and tubers that make some sedges attractive foods. We conclude that although termites and sedges might have contributed to the C4 signal in South African australopiths, other C4 foods were also important. Lastly, we suggest that the consumption of C4 foods is a fundamental hominin trait that, along with bipedalism, allowed australopiths to pioneer increasingly open and seasonal environments.

  13. Cardiovascular Deaths among Alaskan Natives, 1980-86.

    ERIC Educational Resources Information Center

    Middaugh, John P.

    1990-01-01

    Analyzes death certificate data to discover the number of deaths of Alaskan natives caused by cardiovascular disease. Rates from cardiovascular diseases and atherosclerosis from 1980-86 among Alaskan natives were lower than rates among other Alaskans, while death rates from other causes were higher. Discusses the possible impact of diet. (JS)

  14. 7 CFR 1780.49 - Rural or Native Alaskan villages.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Rural or Native Alaskan village. A rural or Native Alaskan community which meets the definition of a... waterborne communicable disease have been documented; or (ii) No community-wide water and sewer system exists... 7 Agriculture 12 2012-01-01 2012-01-01 false Rural or Native Alaskan villages. 1780.49...

  15. 7 CFR 1780.49 - Rural or Native Alaskan villages.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Rural or Native Alaskan village. A rural or Native Alaskan community which meets the definition of a... waterborne communicable disease have been documented; or (ii) No community-wide water and sewer system exists... 7 Agriculture 12 2014-01-01 2013-01-01 true Rural or Native Alaskan villages. 1780.49 Section...

  16. 7 CFR 1780.49 - Rural or Native Alaskan villages.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Rural or Native Alaskan village. A rural or Native Alaskan community which meets the definition of a... waterborne communicable disease have been documented; or (ii) No community-wide water and sewer system exists... 7 Agriculture 12 2013-01-01 2013-01-01 false Rural or Native Alaskan villages. 1780.49...

  17. 78 FR 36566 - Endangered and Threatened Wildlife and Plants; Technical Agency Draft Recovery Plan for Golden Sedge

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-18

    ... (67 FR 3120). This species is a rare perennial member of the sedge family (Cyperaceae) endemic to the... this plant occur in the Northeast Cape Fear River watershed in North Carolina. Factors contributing...

  18. Helping Kids Succeed--Alaskan Style.

    ERIC Educational Resources Information Center

    Association of Alaska School Boards, Juneau.

    The purpose of this book is to serve as a tool for individuals helping to make Alaskan communities places where youth can grow up to be strong, capable, and caring. The book is built around the Search Institute's Youth Developmental Assets Framework, which is comprised of the key building blocks in youth development. The book notes 40 assets that…

  19. Alaskan North Slope petroleum systems

    USGS Publications Warehouse

    Magoon, L.B.; Lillis, P.G.; Bird, K.J.; Lampe, C.; Peters, K.E.

    2003-01-01

    Six North Slope petroleum systems are identified, described, and mapped using oil-to-oil and oil-to-source rock correlations, pods of active source rock, and overburden rock packages. To map these systems, we assumed that: a) petroleum source rocks contain 3.2 wt. % organic carbon (TOC); b) immature oil-prone source rocks have hydrogen indices (HI) >300 (mg HC/gm TOC); c) the top and bottom of the petroleum (oil plus gas) window occur at vitrinite reflectance values of 0.6 and 1.0% Ro, respectively; and d) most hydrocarbons are expelled within the petroleum window. The six petroleum systems we have identified and mapped are: a) a southern system involving the Kuna-Lisburne source rock unit that was active during the Late Jurassic and Early Cretaceous; b) two western systems involving source rock in the Kingak-Blankenship, and GRZ-lower Torok source rock units that were active during the Albian; and c) three eastern systems involving the Shublik-Otuk, Hue Shale and Canning source rock units that were active during the Cenozoic. The GRZ-lower Torok in the west is correlative with the Hue Shale to the east. Four overburden rock packages controlled the time of expulsion and gross geometry of migration paths: a) a southern package of Early Cretaceous and older rocks structurally-thickened by early Brooks Range thrusting; b) a western package of Early Cretaceous rocks that filled the western part of the foreland basin; c) an eastern package of Late Cretaceous and Paleogene rocks that filled the eastern part of the foreland basin; and d) an offshore deltaic package of Neogene rocks deposited by the Colville, Canning, and Mackenzie rivers. This petroleum system poster is part of a series of Northern Alaska posters on modeling. The poster in this session by Saltus and Bird present gridded maps for the greater Northern Alaskan onshore and offshore that are used in the 3D modeling poster by Lampe and others. Posters on source rock units are by Keller and Bird as well as

  20. Organochlorine residues in eggs of Alaskan seabirds

    USGS Publications Warehouse

    Ohlendorf, H.M.; Bartonek, J.C.; Divoky, G.J.; Klass, E.

    1982-01-01

    One egg from each of 440 clutches of eggs of 19 species of Alaskan seabirds collected in 1973-76 was analyzed for organochlorine residues. All eggs contained DDE; 98.9% contained PCB's; 84.3%, oxychlordane; and 82.7%, HCB. Endrin was found in only one egg, but DDD, DDT, dieldrin, heptachlor epoxide, mirex, cis-chlordane (or trans-nonachlor), cis-nonachlor, and toxaphene each occurred in at least 22% of the samples.Concentrations of organochlorines in the samples were generally low. Mean concentrations of eight compounds were highest in eggs of glaucous-winged gulls (Larus glaucescens) from three sites: DDE (5.16 ppm, wet weight), dieldrin (0.214 ppm), oxychlordane (0.251 ppm), and PCB's (3.55 ppm) in eggs from Bogoslof Island; heptachlor epoxide (0.037 ppm), cis-chlordane (0.075 ppm), and HCB (0.188 ppm) in eggs from Buldir Island; and cis-nonachlor (0.026 ppm) in eggs from the Semidi Islands. Highest concentrations of DDD (0.157 ppm), DDT (0.140 ppm), and toxaphene (0.101 ppm) were in eggs of fork-tailed storm-petrel (Oceanodroma furcata) from Buldir Island, and the highest concentration of mirex (0.044 ppm) was in fork-tailed storm-petrel eggs from the Barren Islands.Both frequency of occurrence and concentration of residues in the eggs differed geographically and by species, apparently reflecting non-uniform distribution of organochlorines in the environment, dissimilar feeding habits and migration patterns of the species, or metabolic differences among the species.The overall frequency of residue occurrence was highest in eggs from the Pribilof Islands, but only three species were represented in the samples collected there. Detectable residues also were more frequent in eggs from the Gulf of Alaska colonies than elsewhere, and the lowest frequency was in eggs from nesting colonies on or near the Seward Peninsula. Regionally, concentrations of DDE and PCB's were usually higher than average in eggs from the Gulf of Alaska and lower than average in eggs from the

  1. Offshore oil in the Alaskan Arctic

    NASA Technical Reports Server (NTRS)

    Weeks, W. F.; Weller, G.

    1984-01-01

    Oil and gas deposits in the Alaskan Arctic are estimated to contain up to 40 percent of the remaining undiscovered crude oil and oil-equivalent natural gas within U.S. jurisdiction. Most (65 to 70 percent) of these estimated reserves are believed to occuur offshore beneath the shallow, ice-covered seas of the Alaskan continental shelf. Offshore recovery operations for such areas are far from routine, with the primary problems associated with the presence of ice. Some problems that must be resolved if efficient, cost-effective, environmentally safe, year-round offshore production is to be achieved include the accurate estimation of ice forces on offshore structures, the proper placement of pipelines beneath ice-produced gouges in the sea floor, and the cleanup of oil spills in pack ice areas.

  2. The Role of Sedges in Methane Production and Emission From a Temperate Fen

    NASA Astrophysics Data System (ADS)

    Noyce, G. L.; Szarkowski, E. R.; Bubier, J. L.; Varner, R. K.

    2008-12-01

    Northern peatlands are the largest single natural source of atmospheric methane (CH4) and thus any changes in these fluxes could have global consequences. Positive correlations have been observed between sedge biomass and high CH4 emissions from peatlands. We examined the effect that Carex rostrata has on methane production and transport in Sallie's Fen, Barrington, NH. During the summer of 2008, CH4 fluxes, pore-water CH4 concentrations, and C. rostrata biomass, along with temperature, net ecosystem CO2 exchange (NEE), and water table depth, were measured from both clipped and unclipped plots. In clipped plots, all C. rostrata were clipped below the peat surface and then sealed with petroleum jelly and plastic bags. Unclipped plots were left undisturbed. We observed a strong positive correlation between C. rostrata biomass and CH4 fluxes. Initial findings suggest that sedges have a strong effect on gas transport. The average 18 cm (C. rostrata rooting depth) pore water CH4 concentrations in the clipped plots (6141 ppm CH4) were significantly higher (p<0.001) than in the unclipped plots (3912 ppm CH4). The past 20 years of data at Sallie's Fen also show that plots with more C. rostrata have higher mid-season CH4 fluxes, on average, than shrub-dominated plots. Depth to water table, however, may be a stronger control on CH4 fluxes than vegetation.

  3. Invertebrate community composition differs between invasive herb alligator weed and native sedges

    NASA Astrophysics Data System (ADS)

    Bassett, Imogen E.; Paynter, Quentin; Beggs, Jacqueline R.

    2012-05-01

    Chemical and/or architectural differences between native and exotic plants may influence invertebrate community composition. According to the enemy release hypothesis, invasive weeds should host fewer and less specialised invertebrates than native vegetation. Invertebrate communities were compared on invasive Alternanthera philoxeroides (alligator weed) and native sedges (Isolepis prolifer and Schoenoplectus tabernaemontani) in a New Zealand lake. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Lower invertebrate abundance, richness and proportionally fewer specialists were predicted on A. philoxeroides compared to native sedges, but with greatest differences between A. philoxeroides and S. tabernaemontani. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Invertebrate abundance showed taxa-specific responses, rather than consistently lower abundance on A. philoxeroides. Nevertheless, as predicted, invertebrate fauna of A. philoxeroides was more similar to that of I. prolifer than to S. tabernaemontani. The prediction of a depauperate native fauna on A. philoxeroides received support from some but not all taxa. All vegetation types hosted generalist-dominated invertebrate communities with simple guild structures. The enemy release hypothesis thus had minimal ability to predict patterns in this system. Results suggest the extent of architectural and chemical differences between native and invasive vegetation may be useful in predicting the extent to which they will host different invertebrate communities. However, invertebrate ecology also affects whether invertebrate taxa respond positively or negatively to weed invasion. Thus, exotic vegetation may support distinct invertebrate communities despite similar overall invertebrate abundance to native vegetation.

  4. Emissions of biogenic sulfur gases from Alaskan tundra

    NASA Technical Reports Server (NTRS)

    Hines, Mark E.; Morrison, Michael C.

    1992-01-01

    Results of sulfur emission measurements made in freshwater and marine wetlands in Alaskan tundra during the Arctic Boundary Layer Expedition 2A (ABLE 3A) in July 1988 are presented. The data indicate that this type of tundra emits very small amounts of gaseous sulfur and, when extrapolated globally, accounts for a very small percentage of the global flux of biogenic sulfur to the atmosphere. Sulfur emissions from marine sites are up to 20-fold greater than fluxes from freshwater habitats and are dominated by dimethyl sulfide (DMS). Highest emissions, with a mean of 6.0 nmol/sq m/h, occurred in water-saturated wet meadow areas. In drier upland tundra sites, highest fluxes occurred in areas inhabited by mixed vegetation and labrador tea at 3.0 nmol/sq m/h and lowest fluxes were from lichen-dominated areas at 0.9 nmol/sq m/h. DMS was the dominant gas emitted from all these sites. Emissions of DMS were highest from intertidal soils inhabited by Carex subspathacea.

  5. Can nutrients alone shift a sedge meadow towards dominance by the invasive Typha × glauca

    USGS Publications Warehouse

    Woo, Isa; Zedler, Joy B.

    2002-01-01

    Where wetlands receive urban runoff, Typha spp. and other invasive plants often displace the native vegetation. We tested the ability of nutrients (N and P) to increase vegetative growth of T. × glauca(a hybrid of T. latifolia and T. angustifolia). In the greenhouse, 17 treatments revealed that T. × glauca required both N and P for growth, and total leaf length was most stimulated where a higher proportion of P was added (7N∶1P vs. 14N∶1P, with N constant and P changed), regardless of concentration (the High treatment was 4× the Low treatment). In Gardner Marsh (Madison, Wisconsin, USA), we set up 28 plots (1×6 m) that bisected the boundary between sedge meadow (graminoids) and T. × glauca, and we added a common lawn fertilizer (9N∶1P∶4K) at high (62.5 g/m2), medium (31.3 g/m2), low (15.6 g/m2), and control (0 g/m2) rates on five dates, with n=7 plots/treatment. After one growing season, fertilizer addition increased T. × glauca ramet density, height, and biomass, especially where the sedge meadow graminoids were initially dominant. Aboveground biomass of T. × glauca in the high nutrient addition treatment (1029±256.1 g/m2) was more than double that for control plots (431±80.52 g/m2) overall, with the greatest percent increase in sedge meadow subplots. In contrast, native graminoids (mostly Carex spp.) did not respond to treatment, either in biomass or percent cover. Typha × glauca allocated nutrients to both growth and storage, as indicated by higher N and P concentrations in leaves, shoot bases, and rhizomes in plots with high nutrient addition. Because fertilizing the marsh enhanced the shoot growth of T. × glauca but not native graminoids, and because the 7N∶1P treatment stimulated growth in the greenhouse, we suggest that wetland managers focus on reducing P inflows to urban wetlands. Fertilizer additions below those recommended by the manufacturer for new lawns (5× that of our highest treatment) should be more

  6. 7 CFR 1780.49 - Rural or Native Alaskan villages.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... providing grants to remedy the dire sanitation conditions in rural Alaskan villages using funds specifically... 7 Agriculture 12 2011-01-01 2011-01-01 false Rural or Native Alaskan villages. 1780.49 Section 1780.49 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES...

  7. 7 CFR 1780.49 - Rural or Native Alaskan villages.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... providing grants to remedy the dire sanitation conditions in rural Alaskan villages using funds specifically... 7 Agriculture 12 2010-01-01 2010-01-01 false Rural or Native Alaskan villages. 1780.49 Section 1780.49 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES...

  8. Educational Provisions for the Alaskan Natives Since 1867.

    ERIC Educational Resources Information Center

    Hopkins, Thomas Robert

    The study compiles and records the history of the administration of education for Alaskan natives since the United States purchased the territory from Russia in 1876. Chapter 1, An Overview of the Development of the Alaskan Native, covers the development of missionary and government schools, the growth and development of Native education from 1906…

  9. Contribution of arbuscular mycorrhizal fungi of sedges to soil aggregation along an altitudinal alpine grassland gradient on the Tibetan Plateau.

    PubMed

    Li, Xiaoliang; Zhang, Junling; Gai, Jingping; Cai, Xiaobu; Christie, Peter; Li, Xiaolin

    2015-08-01

    The diversity of arbuscular mycorrhizal fungi (AMF) in sedges on the Tibetan Plateau remains largely unexplored, and their contribution to soil aggregation can be important in understanding the ecological function of AMF in alpine ecosystems. Roots of Kobresia pygmaea C.B. Clarke and Carex pseudofoetida Kük. in alpine Kobresia pastures along an elevational transect (4149-5033 m) on Mount Mila were analysed for AMF diversity. A structural equation model was built to explore the contribution of biotic factors to soil aggregation. Sedges harboured abundant AMF communities covering seven families and some operational taxonomic units are habitat specific. The two plant species hosted similar AMF communities at most altitudes. The relative abundance of the two sedges contributed largely to soil macroaggregates, followed by extraradical mycorrhizal hyphae (EMH) and total glomalin-related soil protein (T-GRSP). The influence of plant richness was mainly due to its indirect influence on T-GRSP and EMH. There was a strong positive correlation between GRSP and soil total carbon and nitrogen. Our results indicate that mycorrhization might not be a major trait leading to niche differentiation of the two co-occurring sedge species. However, AMF contribute to soil aggregation and thus may have the potential to greatly influence C and N cycling in alpine grasslands.

  10. Soil Redox Chemistry Limitation of Selenium Concentration in Carex Species Sedges

    SciTech Connect

    Bruce J. Mincher; John Mionczynski; Patrick A. Hnilicka

    2007-09-01

    The trace element selenium (Se) is required in the production of enzymes that protect mammalian cells from oxidative damage due to the byproducts of aerobic respiration. Its deficiency in livestock results in the nutritional muscular dystrophy called white muscle disease. This especially affects juveniles in the preweaning period. Symptoms have also been reported in wild herbivores on low-Se forage, and their appearance may be episodic, suggesting temporal variations in Se uptake by plants. Here, we report variations in selenium concentrations in Carex spp. sedges used as forage by bighorn sheep (Ovis canadensis) on summer range in the Wyoming, Wind River Mountains, and correlate those variations with soil conditions that affect the bioavailability of selenium. Variations in available Se are explained based upon the known oxidation/reduction chemistry of the element. It is concluded that water-saturated, alpine soils provide conditions suitable for the reduction of Se to the unavailable, elemental form, limiting its concentration in forage plants.

  11. Development and characterization of 11 microsatellite primers for the sedge Trichophorum planifolium (Cyperaceae)1

    PubMed Central

    Nowell, Victoria J.; Wang, Song; Smith, Tyler W.

    2015-01-01

    Premise of the study: Microsatellite loci were developed for Trichophorum planifolium (Cyperaceae), an endangered woodland sedge protected under federal and provincial legislation in Canada, to explore patterns of population genetic diversity and differentiation in the species. Methods and Results: Sixty-three primer pairs were evaluated for amplification consistency and screened for polymorphisms in 96 samples collected from 12 populations of T. planifolium distributed through the range of the species. Of these, 11 loci were shown to be polymorphic, displaying two to six alleles. Mean observed heterozygosity across loci ranged from 0.00 to 0.06 among populations tested. Conclusions: The results suggest that the 11 primer pairs developed in this study will be useful for future studies of broad-scale genetic variation in T. planifolium and in guiding management protocols for the species in Canada. PMID:26421254

  12. Carbon cycle uncertainty in the Alaskan Arctic

    NASA Astrophysics Data System (ADS)

    Fisher, J. B.; Sikka, M.; Oechel, W. C.; Huntzinger, D. N.; Melton, J. R.; Koven, C. D.; Ahlström, A.; Arain, M. A.; Baker, I.; Chen, J. M.; Ciais, P.; Davidson, C.; Dietze, M.; El-Masri, B.; Hayes, D.; Huntingford, C.; Jain, A. K.; Levy, P. E.; Lomas, M. R.; Poulter, B.; Price, D.; Sahoo, A. K.; Schaefer, K.; Tian, H.; Tomelleri, E.; Verbeeck, H.; Viovy, N.; Wania, R.; Zeng, N.; Miller, C. E.

    2014-08-01

    Climate change is leading to a disproportionately large warming in the high northern latitudes, but the magnitude and sign of the future carbon balance of the Arctic are highly uncertain. Using 40 terrestrial biosphere models for the Alaskan Arctic from four recent model intercomparison projects - NACP (North American Carbon Program) site and regional syntheses, TRENDY (Trends in net land atmosphere carbon exchanges), and WETCHIMP (Wetland and Wetland CH4 Inter-comparison of Models Project) - we provide a baseline of terrestrial carbon cycle uncertainty, defined as the multi-model standard deviation (σ) for each quantity that follows. Mean annual absolute uncertainty was largest for soil carbon (14.0 ± 9.2 kg C m-2), then gross primary production (GPP) (0.22 ± 0.50 kg C m-2 yr-1), ecosystem respiration (Re) (0.23 ± 0.38 kg C m-2 yr-1), net primary production (NPP) (0.14 ± 0.33 kg C m-2 yr-1), autotrophic respiration (Ra) (0.09 ± 0.20 kg C m-2 yr-1), heterotrophic respiration (Rh) (0.14 ± 0.20 kg C m-2 yr-1), net ecosystem exchange (NEE) (-0.01 ± 0.19 kg C m-2 yr-1), and CH4 flux (2.52 ± 4.02 g CH4 m-2 yr-1). There were no consistent spatial patterns in the larger Alaskan Arctic and boreal regional carbon stocks and fluxes, with some models showing NEE for Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. Finally, AmeriFlux data are used at two sites in the Alaskan Arctic to evaluate the regional patterns; observed seasonal NEE was captured within multi-model uncertainty. This assessment of carbon cycle uncertainties may be used as a baseline for the improvement of experimental and modeling activities, as well as a reference for future trajectories in carbon cycling with climate change in the Alaskan Arctic and larger boreal region.

  13. Engaging Alaskan Students in Cryospheric Research

    NASA Astrophysics Data System (ADS)

    Yoshikawa, K.; Sparrow, E. B.; Kopplin, M.

    2011-12-01

    The Permafrost/Active Layer Monitoring Program is an ongoing project, which builds on work begun in 2005 to establish long-term permafrost and active layer monitoring sites adjacent to schools in Alaskan communities and in the circumpolar permafrost region. Currently, there are about 200 schools in Alaska involved in the project including also Denali National Park and Preserve. The project has both scientific and outreach components. The monitoring sites collect temperature data on permafrost, and the length and depth of the active layer (the layer above the permafrost that thaws during summer and freezes again during winter). To ensure scientific integrity, the scientist installed all of the monitoring instruments and selected the sites representative of the surrounding biome and thermal conditions. This is a unique collaboration opportunity in that 1) uses scientifically accurate instruments, 2) is scientist led and supervised including instrumentation set-up and data quality check, 3)has teacher/student organized observation network, 4) increased spatial scale of monitoring sites that covers all of the Alaskan communities. Most of the monitoring sites are located in remote communities, where the majority of residents depend on a subsistence lifestyle. Changes in climate, length of seasons, and permafrost conditions directly impact natural resources and subsistence activities. Changes in permafrost conditions also affect local ecosystems and hydrological regimes, and can influence the severity of natural disasters. In addition to extending our knowledge of the arctic environment, the program involves school-age students. Several students have been using the data for their projects and have been inspired to continue their studies. The data gathered from these stations are shared with other schools and made available to the public through our web site (http://www.uaf.edu/permafrost). Also communities have increasingly become interested in this project not only as

  14. Greater shrub dominance alters breeding habitat and food resources for migratory songbirds in Alaskan arctic tundra.

    PubMed

    Boelman, Natalie T; Gough, Laura; Wingfield, John; Goetz, Scott; Asmus, Ashley; Chmura, Helen E; Krause, Jesse S; Perez, Jonathan H; Sweet, Shannan K; Guay, Kevin C

    2015-04-01

    Climate warming is affecting the Arctic in multiple ways, including via increased dominance of deciduous shrubs. Although many studies have focused on how this vegetation shift is altering nutrient cycling and energy balance, few have explicitly considered effects on tundra fauna, such as the millions of migratory songbirds that breed in northern regions every year. To understand how increasing deciduous shrub dominance may alter breeding songbird habitat, we quantified vegetation and arthropod community characteristics in both graminoid and shrub dominated tundra. We combined measurements of preferred nest site characteristics for Lapland longspurs (Calcarius lapponicus) and Gambel's White-crowned sparrows (Zonotrichia leucophrys gambelii) with modeled predictions for the distribution of plant community types in the Alaskan arctic foothills region for the year 2050. Lapland longspur nests were found in sedge-dominated tussock tundra where shrub height does not exceed 20 cm, whereas White-crowned sparrows nested only under shrubs between 20 cm and 1 m in height, with no preference for shrub species. Shrub canopies had higher canopy-dwelling arthropod availability (i.e. small flies and spiders) but lower ground-dwelling arthropod availability (i.e. large spiders and beetles). Since flies are the birds' preferred prey, increasing shrubs may result in a net enhancement in preferred prey availability. Acknowledging the coarse resolution of existing tundra vegetation models, we predict that by 2050 there will be a northward shift in current White-crowned sparrow habitat range and a 20-60% increase in their preferred habitat extent, while Lapland longspur habitat extent will be equivalently reduced. Our findings can be used to make first approximations of future habitat change for species with similar nesting requirements. However, we contend that as exemplified by this study's findings, existing tundra modeling tools cannot yet simulate the fine-scale habitat

  15. Greater shrub dominance alters breeding habitat and food resources for migratory songbirds in Alaskan arctic tundra.

    PubMed

    Boelman, Natalie T; Gough, Laura; Wingfield, John; Goetz, Scott; Asmus, Ashley; Chmura, Helen E; Krause, Jesse S; Perez, Jonathan H; Sweet, Shannan K; Guay, Kevin C

    2015-04-01

    Climate warming is affecting the Arctic in multiple ways, including via increased dominance of deciduous shrubs. Although many studies have focused on how this vegetation shift is altering nutrient cycling and energy balance, few have explicitly considered effects on tundra fauna, such as the millions of migratory songbirds that breed in northern regions every year. To understand how increasing deciduous shrub dominance may alter breeding songbird habitat, we quantified vegetation and arthropod community characteristics in both graminoid and shrub dominated tundra. We combined measurements of preferred nest site characteristics for Lapland longspurs (Calcarius lapponicus) and Gambel's White-crowned sparrows (Zonotrichia leucophrys gambelii) with modeled predictions for the distribution of plant community types in the Alaskan arctic foothills region for the year 2050. Lapland longspur nests were found in sedge-dominated tussock tundra where shrub height does not exceed 20 cm, whereas White-crowned sparrows nested only under shrubs between 20 cm and 1 m in height, with no preference for shrub species. Shrub canopies had higher canopy-dwelling arthropod availability (i.e. small flies and spiders) but lower ground-dwelling arthropod availability (i.e. large spiders and beetles). Since flies are the birds' preferred prey, increasing shrubs may result in a net enhancement in preferred prey availability. Acknowledging the coarse resolution of existing tundra vegetation models, we predict that by 2050 there will be a northward shift in current White-crowned sparrow habitat range and a 20-60% increase in their preferred habitat extent, while Lapland longspur habitat extent will be equivalently reduced. Our findings can be used to make first approximations of future habitat change for species with similar nesting requirements. However, we contend that as exemplified by this study's findings, existing tundra modeling tools cannot yet simulate the fine-scale habitat

  16. [Wet work].

    PubMed

    Kieć-Swierczyńska, Marta; Chomiczewska, Dorota; Krecisz, Beata

    2010-01-01

    Wet work is one of the most important risk factors of occupational skin diseases. Exposure of hands to the wet environment for more than 2 hours daily, wearing moisture-proof protective gloves for a corresponding period of time or necessity to wash hands frequently lead to the disruption of epidermal stratum corneum, damage to skin barrier function and induction of irritant contact dermatitis. It may also promote penetration of allergens into the skin and increase the risk of sensitization to occupational allergens. Exposure to wet work plays a significant role in occupations, such as hairdressers and barbers, nurses and other health care workers, cleaning staff, food handlers and metalworkers. It is more common among women because many occupations involving wet work are female-dominated. The incidence of wet-work-induced occupational skin diseases can be reduced by taking appropriate preventive measures. These include identification of high-risk groups, education of workers, organization of work enabling to minimize the exposure to wet work, use of personal protective equipment and skin care after work.

  17. Response of plant community structure and primary productivity to experimental drought and flooding in an Alaskan fen

    USGS Publications Warehouse

    Churchill, A.C.; Turetsky, Merritt R.; McGuire, Anthony; Hollingsworth, Teresa N.

    2014-01-01

    Northern peatlands represent a long-term net sink for atmospheric CO2, but these ecosystems can shift from net carbon (C) sinks to sources based on changing climate and environmental conditions. In particular, changes in water availability associated with climate control peatland vegetation and carbon uptake processes. We examined the influence of changing hydrology on plant species abundance and ecosystem primary production in an Alaskan fen by manipulating the water table in field treatments to mimic either sustained flooding (raised water table) or drought (lowered water table) conditions for 6 years. We found that water table treatments altered plant species abundance by increasing sedge and grass cover in the raised water table treatment and reducing moss cover while increasing vascular green area in the lowered water table treatment. Gross primary productivity was lower in the lowered treatment than in the other plots, although there were no differences in total biomass or vascular net primary productivity among the treatments. Overall, our results indicate that vegetation abundance was more sensitive to variation in water table than total biomass and vascular biomass accrual. Finally, in our experimental peatland, drought had stronger consequences for change in vegetation abundance and ecosystem function than sustained flooding.

  18. Comparative metagenome analysis of an Alaskan glacier.

    PubMed

    Choudhari, Sulbha; Lohia, Ruchi; Grigoriev, Andrey

    2014-04-01

    The temperature in the Arctic region has been increasing in the recent past accompanied by melting of its glaciers. We took a snapshot of the current microbial inhabitation of an Alaskan glacier (which can be considered as one of the simplest possible ecosystems) by using metagenomic sequencing of 16S rRNA recovered from ice/snow samples. Somewhat contrary to our expectations and earlier estimates, a rich and diverse microbial population of more than 2,500 species was revealed including several species of Archaea that has been identified for the first time in the glaciers of the Northern hemisphere. The most prominent bacterial groups found were Proteobacteria, Bacteroidetes, and Firmicutes. Firmicutes were not reported in large numbers in a previously studied Alpine glacier but were dominant in an Antarctic subglacial lake. Representatives of Cyanobacteria, Actinobacteria and Planctomycetes were among the most numerous, likely reflecting the dependence of the ecosystem on the energy obtained through photosynthesis and close links with the microbial community of the soil. Principal component analysis (PCA) of nucleotide word frequency revealed distinct sequence clusters for different taxonomic groups in the Alaskan glacier community and separate clusters for the glacial communities from other regions of the world. Comparative analysis of the community composition and bacterial diversity present in the Byron glacier in Alaska with other environments showed larger overlap with an Arctic soil than with a high Arctic lake, indicating patterns of community exchange and suggesting that these bacteria may play an important role in soil development during glacial retreat.

  19. Sufentanil citrate immobilization of Alaskan moose calves.

    PubMed

    Kreeger, Terry J; Kellie, Kalin A

    2012-10-01

    Free-ranging Alaskan moose calves (Alces alces gigas) were immobilized with 0.12 mg/kg sufentanil (S; n=16), 0.12 mg/kg sufentanil plus 0.27 mg/kg xylazine (SX; n=11), or 0.007 mg/kg carfentanil plus 0.36 mg/kg xylazine (CX; n=13). Immobilants were antagonized with 1.2 mg/kg naltrexone (S) or 1.2 mg/kg naltrexone plus 2.4 mg/kg tolazoline (SX, CX). There were no differences in induction (P ≥ 0.29) or processing (P ≥ 0.44) times between groups. Moose given either S or SX had significantly shorter recovery times than moose given CX (P=0.001) and recovery times from S were shorter than from SX (P=0.02). Oxygen saturation values for all groups averaged 85 ± 8%, but were significantly higher (P=0.048) for CX (89 ± 7%) than for S (82 ± 8%). Based on these data, sufentanil at 0.1 mg/kg or sufentanil at 0.1 mg/kg plus xylazine at 0.25 mg/kg could provide effective remote immobilization for Alaskan moose calves and could be substituted for carfentanil or thiafentanil should the need arise.

  20. Emissions of biogenic sulfur gases from Alaskan tundra

    SciTech Connect

    Hines, M.E.; Morrison, M.C.

    1992-10-30

    Fluxes of the biogenic sulfur gases carbonyl sulfide (COS), dimethyl sulfide (DMS), methyl mercaptan (MeSH), and carbon disulfide (CS{sub 2}) were determined from several freshwater and coastal marine tundra habitats using a dynamic enclosure method and gas chromatography. In the freshwater tundra sites, highest emissions, with a mean of 6.0 nmol m{sup {minus}2}h{sup {minus}1} (1.5-10) occurred in the water-saturated wet meadow areas inhabited by grasses, sedges, and Shpagnum mosses. In the drier upland tundra sites, highest fluxes occurred in areas inhabited by mixed vegetation and labrador tea at 3.0 nmol m{sup {minus}2}h{sup {minus}1} (0-8.3) and lowest fluxes were from lichen-dominated areas at 0.8 nmol m{sup {minus}2}h{sup {minus}1}. Sulfur emissions from a lake surface were also low at 0.8 nmol m{sup {minus}2}h{sup {minus}1}. Of the compounds measured, DMS was the dominant gas emitted from all of these sites. Sulfur emissions from the marine sites were up to 20-fold greater than fluxes in the freshwater habitats and were also dominated by DMS. Emissions of DMS were highest from intertidal soils inhabited by Carex subspathacea. This Carex sp. was grazed thoroughly by geese and DMS fluxes doubled when goose feces were left within the flux chamber. Emissions were much lower from other types of vegetation which were more spatially dominant. Sulfur emissions from tundra were among the lowest reported in the literature. When emission data were extrapolated to include all tundra globally, the global flux of biogenic sulfur from this biome is 2-3 x 10{sup 8} g yr{sup {minus}1}. This represents less than 0.001% of the estimated annual global flux of biogenic sulfur and <0.01% of the estimated terrestrial flux. The low emissions are attributed to the low availability of sulfate, certain hydrological characteristics of tundra, and the tendency for tundra to accumulate organic matter. 31 refs., 1 fig., 2 tabs.

  1. Emissions of biogenic sulfur gases from Alaskan tundra

    NASA Technical Reports Server (NTRS)

    Hines, Mark E.; Morrison, Michael C.

    1992-01-01

    Fluxes of the biogenic sulfur gases carbonyl sulfide (COS), dimethyl sulfide (DMS), methyl mercaptan (MeSH), and carbon disulfide (CS2) were determined for several freshwater and coastal marine tundra habitats using a dynamic enclosure method and gas chromatography. In the freshwater tundra sites, highest emissions, with a mean of 6.0 nmol/m(sup -2)H(sup -1) (1.5-10) occurred in the water-saturated wet meadow areas inhabited by grasses, sedges, and Sphagnum mosses. In the drier upland tundra sites, highest fluxes occurred in areas inhabited by mixed vegetation and labrador tea at 3.0 nmol/m(sup -2)h(sup -1) (0-8.3) and lowest fluxes were from lichen-dominated areas at 0.9 nmol/m(sup -2)h(sup -1). Sulfur emissions from a lake surface were also low at 0.8 nmol/m(sup -2)h(sup -1). Of the compounds measured, DMS was the dominant gas emitted from all of these sites. Sulfure emissions from the marine sites were up to 20-fold greater than fluxes in the freshwater habitats and were also dominated by DMS. Emissions of DMS were highest from intertidal soils inhabited by Carex subspathacea (150-250 nmol/m(sup -2)h(sup -1)). This Carex sp. was grazed thoroughly by geese and DMS fluxes doubled when goose feces were left within the flux chamber. Emissions were much lower from other types of vegetation which were more spatially dominant. Sulfure emissions from tundra were among the lowest reported in the literature. When emission data were extrapolated to include all tundra globally, the global flux of biogenic sulfur from this biome is 2-3 x 10(exp 8) g/yr. This represents less than 0.001 percent of the estimated annual global flux (approximately 50 Tg) of biogenic sulfur and less than 0.01 percent of the estimated terrestrial flux. The low emissions are attributed to the low availability of sulfate, certain hydrological characteristics of tundra, and the tendency for tundra to accumulate organic matter.

  2. Carbon cycle uncertainty in the Alaskan Arctic

    NASA Astrophysics Data System (ADS)

    Fisher, J. B.; Sikka, M.; Oechel, W. C.; Huntzinger, D. N.; Melton, J. R.; Koven, C. D.; Ahlström, A.; Arain, A. M.; Baker, I.; Chen, J. M.; Ciais, P.; Davidson, C.; Dietze, M.; El-Masri, B.; Hayes, D.; Huntingford, C.; Jain, A.; Levy, P. E.; Lomas, M. R.; Poulter, B.; Price, D.; Sahoo, A. K.; Schaefer, K.; Tian, H.; Tomelleri, E.; Verbeeck, H.; Viovy, N.; Wania, R.; Zeng, N.; Miller, C. E.

    2014-02-01

    Climate change is leading to a disproportionately large warming in the high northern latitudes, but the magnitude and sign of the future carbon balance of the Arctic are highly uncertain. Using 40 terrestrial biosphere models for Alaska, we provide a baseline of terrestrial carbon cycle structural and parametric uncertainty, defined as the multi-model standard deviation (σ) against the mean (x\\bar) for each quantity. Mean annual uncertainty (σ/x\\bar) was largest for net ecosystem exchange (NEE) (-0.01± 0.19 kg C m-2 yr-1), then net primary production (NPP) (0.14 ± 0.33 kg C m-2 yr-1), autotrophic respiration (Ra) (0.09 ± 0.20 kg C m-2 yr-1), gross primary production (GPP) (0.22 ± 0.50 kg C m-2 yr-1), ecosystem respiration (Re) (0.23 ± 0.38 kg C m-2 yr-1), CH4 flux (2.52 ± 4.02 g CH4 m-2 yr-1), heterotrophic respiration (Rh) (0.14 ± 0.20 kg C m-2 yr-1), and soil carbon (14.0± 9.2 kg C m-2). The spatial patterns in regional carbon stocks and fluxes varied widely with some models showing NEE for Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. Additionally, a feedback (i.e., sensitivity) analysis was conducted of 20th century NEE to CO2 fertilization (β) and climate (γ), which showed that uncertainty in γ was 2x larger than that of β, with neither indicating that the Alaskan Arctic is shifting towards a certain net carbon sink or source. Finally, AmeriFlux data are used at two sites in the Alaskan Arctic to evaluate the regional patterns; observed seasonal NEE was captured within multi-model uncertainty. This assessment of carbon cycle uncertainties may be used as a baseline for the improvement of experimental and modeling activities, as well as a reference for future trajectories in carbon cycling with climate change in the Alaskan Arctic.

  3. Atmospheric methane sources - Alaskan tundra bogs, an alpine fen, and a subarctic boreal marsh

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Harriss, R. C.; Grice, S. S.; Bartlett, K. B.; Sebacher, S. M.

    1986-01-01

    Methane (CH4) flux measurements from Alaska tundra bogs, an alpine fen, and a subarctic boreal marsh were obtained at field sites ranging from Prudhoe Bay on the coast of the Arctic Ocean to the Alaskan Range south of Fairbanks during August 1984. In the tundra, average CH4 emission rates varied from 4.9 mg CH4 per sq m per day (moist tundra) to 119 mg CH4 per sq m per day (waterlogged tundra). Fluxes averaged 40 mg CH4 per sq m per day from wet tussock meadows in the Brooks Range and 289 mg Ch4 per sq m per day from an alpine fen in the Alaskan Range. The boreal marsh had an average CH4 emission rate of 106 mg CH4 per sq m per day. Significant emissions were detected in tundra areas where peat temperatures were as low as 4 C, and permafrost was only 25 cm below the ground surface. Emission rates from the 17 sites sampled were found to be logarithmically related to water levels at the sites. Extrapolation of the data to an estimate of the total annual CH4 emission from all arctic and boreal wetlands suggests that these ecosystems are a major source of atmospheric CH4 and could account for up to 23 percent of global CH4 emissions from wetlands.

  4. Development of Alaskan gas hydrate resources

    SciTech Connect

    Kamath, V.A.; Sharma, G.D.; Patil, S.L.

    1991-06-01

    The research undertaken in this project pertains to study of various techniques for production of natural gas from Alaskan gas hydrates such as, depressurization, injection of hot water, steam, brine, methanol and ethylene glycol solutions through experimental investigation of decomposition characteristics of hydrate cores. An experimental study has been conducted to measure the effective gas permeability changes as hydrates form in the sandpack and the results have been used to determine the reduction in the effective gas permeability of the sandpack as a function of hydrate saturation. A user friendly, interactive, menu-driven, numerical difference simulator has been developed to model the dissociation of natural gas hydrates in porous media with variable thermal properties. A numerical, finite element simulator has been developed to model the dissociation of hydrates during hot water injection process.

  5. Subacute necrotising encephalopathy in an Alaskan husky.

    PubMed

    Wakshlag, J J; de Lahunta, A; Robinson, T; Cooper, B J; Brenner, O; O'Toole, T D; Olson, J; Beckman, K B; Glass, E; Reynolds, A J

    1999-12-01

    A 29-month-old female Alaskan husky was presented recumbent, tetraparetic and in a state of dementia, with blindness and cranial nerve deficits. The dog's progress was followed for over two months, as the signs resolved to an non-progressive mild hypermetria with slight proprioceptive ataxia, a diminished menace response and inability to prehend food. Magnetic resonance imaging (MRI) revealed bilateral cavitation extending from the thalamus to the medulla, with less pronounced degenerative lesions in the caudate nucleus, putamen and claustrum. Cerebrospinal fluid lactate and pyruvate concentrations were in their normal ranges. Necropsy and histological examination confirmed the MRI findings as well as neuronal degeneration of the cerebellar cortex in the vermis and degenerative changes in the neocortex at the depths of the cerebral sulci. In view of the similarity of lesions to subacute necrotising encephalomyelopathy, known as Leigh's disease in humans, a tentative diagnosis of a mitochondrial encephalopathy was made.

  6. Gastritis in Alaskan racing sled dogs.

    PubMed

    Ritchey, J W; Davis, M S; Breshears, M A; Willard, M D; Williamson, K K; Royer, C M; Payton, M E; Cragun, A S

    2011-07-01

    Alaskan racing sled dogs are a well-established model of exercise-induced gastric disease. The aim of this study was to define the temporal development of microscopical gastric lesions during long distance racing. Two groups of dogs were examined: group I comprised conditioned dogs that were exercising and group II were conditioned dogs not exercising. The gastric mucosa was examined endoscopically and sampled for routine histopathology and microscopical scoring, immunohistochemistry (IHC) and detection of apoptotic epithelial cells. Overall, group I dogs exhibited more significant epithelial lesions, including ulcers, compared with dogs in group II. Group II dogs exhibited the most severe mucosal inflammatory infiltrates. Although the intensity of inflammation differed, the nature of the inflammation was similar between groups, consisting of diffuse lymphocytic infiltration and a unique interface-type infiltrate that obscured the basement membrane zone and was accompanied by intraepithelial infiltration of lymphocytes. IHC confirmed the presence of CD3(+) T and CD79(+) B lymphocytes within the mucosal infiltrates; however, most of the intraepithelial and interface infiltrates were CD3(+) T cells. Spiral-shaped bacterial organisms were seen in the gastric tissues; however, their presence did not correlate with either the severity of epithelial lesions, inflammation or the pattern of interface inflammation. The number of apoptotic epithelial cells was widely variable and not significantly different between groups. These findings confirm previous observations that gastric ulcers develop in conditioned dogs under racing stress. The unique nature of the interface-type gastric inflammation is similar to that of human lymphocytic gastritis and may suggest an immune-mediated mechanism for the changes seen in Alaskan racing sled dogs.

  7. Sedge (Carex nudata) as a mediator of river channel change in response to grazing reduction and a large flood

    NASA Astrophysics Data System (ADS)

    McDowell, P. F.

    2011-12-01

    Human land use can change vegetation - hydrogeomorphic interactions in ways that exert a major influence on channel form. The native riparian sedge Carex nudata (torrent sedge) was suppressed by cattle grazing in the Middle Fork John Day River in the Blue Mountains of northeastern Oregon, and following the end of grazing in 2000 C. nudata and other sedge populations exploded. Today C. nudata forms highly resistant tussocks on the active channel bed. The tussocks cause both stabilization (of bars and channel bed) and erosion (around the tussocks as resistance elements). C. nudata has stabilized active bars, pool tails and riffle crests. The tussocks behave as boulder-sized resistance elements and create scour holes and appear to increase bank erosion. From a habitat perspective, C. nudata has increased fish cover, as well as the complexity of bed morphology and hydraulic diversity. The flood of record in May 2011 produced only limited erosion of C. nudata tussocks. Comparison of pre and post-flood channel cross-sections shows both the stabilizing and erosive effects of C. nudata. These changes suggest that C. nudata is setting a new trajectory of channel adjustment toward narrower, rougher, more stable, and reduced sediment transport conditions.

  8. Predicted effects of proposed new regulation plans on sedge/grass meadows of Lake Ontario

    USGS Publications Warehouse

    Wilcox, D.A.; Xie, Y.

    2008-01-01

    Previously described models for predicting the percent of Lake Ontario wetlands that would be occupied by sedge/grass-dominated meadow marsh were used to test four proposed new plans for regulation of lake levels and to make comparisons with the current plan and unregulated conditions. The models for drowned river mouth, barrier beach, open embayment, and protected embayment wetlands assessed responses to lake levels that would be generated by each plan under net total supplies modified from those that occurred from1900 to 2000. In years when reduced supplies would allow meadow marsh regeneration, simulated unregulated lake levels produced the most meadow marsh in all wetland geomorphic types; current Plan 1958DD produced the least. Overall predicted percent meadow marsh under the test plans decreased in the order B+, 2007, D+, and A+, and the latter three plans produced rather similar results in many cases. Lower percentages of meadow marsh under some plans were due to insufficient low lake levels that could allow soils to dry and restrict invasion by cattails, as well as lack of periodic high lake levels that could kill invading upland plants. An assessment of seasonal lake-level characteristics demonstrated that Plan 2007 would reduce mean winter lake levels by 13 cm or more than Plan B+ and springtime lake levels by more than 10 cm. These seasonal differences could result in less winter habitat for muskrats and reduced access to spring spawning habitats for fish such as northern pike. Our model results provide important information for use in the process of selecting a new regulation plan for Lake Ontario.

  9. Alaska Is Our Home--Book 3: A Natural Science Handbook for Alaskan Students.

    ERIC Educational Resources Information Center

    Bury, John; Bury, Susan

    The third book in a series of natural science handbooks for Alaskan students focuses on Alaskan plantlife. The first chapter, on trees, gives general information about trees and explains how to identify and locate trees in the three main Alaskan tree families: pine, willow, and birch. The second chapter, on plants, describes 14 kinds of edible…

  10. 40 CFR 408.90 - Applicability; description of the non-remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-remote Alaskan shrimp processing subcategory. 408.90 Section 408.90 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Shrimp Processing Subcategory § 408.90 Applicability; description of the non-remote Alaskan shrimp processing subcategory. The provisions of this subpart...

  11. 40 CFR 408.100 - Applicability; description of the remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... remote Alaskan shrimp processing subcategory. 408.100 Section 408.100 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Shrimp Processing Subcategory § 408.100 Applicability; description of the remote Alaskan shrimp processing subcategory. The provisions of this subpart are...

  12. 40 CFR 408.100 - Applicability; description of the remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... remote Alaskan shrimp processing subcategory. 408.100 Section 408.100 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Shrimp Processing Subcategory § 408.100 Applicability; description of the remote Alaskan shrimp processing subcategory. The provisions of this subpart are...

  13. 40 CFR 408.90 - Applicability; description of the non-remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-remote Alaskan shrimp processing subcategory. 408.90 Section 408.90 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Shrimp Processing Subcategory § 408.90 Applicability; description of the non-remote Alaskan shrimp processing subcategory. The provisions of this subpart...

  14. 40 CFR 408.100 - Applicability; description of the remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... remote Alaskan shrimp processing subcategory. 408.100 Section 408.100 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Shrimp Processing Subcategory § 408.100 Applicability; description of the remote Alaskan shrimp processing subcategory. The provisions of this subpart are...

  15. 40 CFR 408.90 - Applicability; description of the non-remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-remote Alaskan shrimp processing subcategory. 408.90 Section 408.90 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Shrimp Processing Subcategory § 408.90 Applicability; description of the non-remote Alaskan shrimp processing subcategory. The provisions of this subpart...

  16. 40 CFR 408.100 - Applicability; description of the remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... remote Alaskan shrimp processing subcategory. 408.100 Section 408.100 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Shrimp Processing Subcategory § 408.100 Applicability; description of the remote Alaskan shrimp processing subcategory. The provisions of this subpart are...

  17. 40 CFR 408.90 - Applicability; description of the non-remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-remote Alaskan shrimp processing subcategory. 408.90 Section 408.90 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Shrimp Processing Subcategory § 408.90 Applicability; description of the non-remote Alaskan shrimp processing subcategory. The provisions of this subpart...

  18. 40 CFR 408.100 - Applicability; description of the remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... remote Alaskan shrimp processing subcategory. 408.100 Section 408.100 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Shrimp Processing Subcategory § 408.100 Applicability; description of the remote Alaskan shrimp processing subcategory. The provisions of this subpart are...

  19. 40 CFR 408.90 - Applicability; description of the non-remote Alaskan shrimp processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-remote Alaskan shrimp processing subcategory. 408.90 Section 408.90 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Shrimp Processing Subcategory § 408.90 Applicability; description of the non-remote Alaskan shrimp processing subcategory. The provisions of this subpart...

  20. 40 CFR 408.200 - Applicability; description of the Alaskan bottom fish processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Alaskan bottom fish processing subcategory. 408.200 Section 408.200 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Bottom Fish Processing Subcategory § 408.200 Applicability; description of the Alaskan bottom fish processing subcategory. The provisions of this subpart are...

  1. 40 CFR 408.200 - Applicability; description of the Alaskan bottom fish processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Alaskan bottom fish processing subcategory. 408.200 Section 408.200 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Bottom Fish Processing Subcategory § 408.200 Applicability; description of the Alaskan bottom fish processing subcategory. The provisions of this subpart are...

  2. 40 CFR 408.200 - Applicability; description of the Alaskan bottom fish processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Alaskan bottom fish processing subcategory. 408.200 Section 408.200 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Bottom Fish Processing Subcategory § 408.200 Applicability; description of the Alaskan bottom fish processing subcategory. The provisions of this subpart are...

  3. 40 CFR 408.200 - Applicability; description of the Alaskan bottom fish processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Alaskan bottom fish processing subcategory. 408.200 Section 408.200 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Bottom Fish Processing Subcategory § 408.200 Applicability; description of the Alaskan bottom fish processing subcategory. The provisions of this subpart are...

  4. 40 CFR 408.200 - Applicability; description of the Alaskan bottom fish processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Alaskan bottom fish processing subcategory. 408.200 Section 408.200 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Bottom Fish Processing Subcategory § 408.200 Applicability; description of the Alaskan bottom fish processing subcategory. The provisions of this subpart are...

  5. American Indian Policy Review Commission Special Joint Task Force Report on Alaskan Native Issues.

    ERIC Educational Resources Information Center

    Congress of the U.S. Washington, DC. American Indian Policy Review Commission.

    Impact of the Alaskan Native Claims Settlement Act (ANCSA) on Alaskan Natives, particularly at village levels, is the focus of a joint task force report on Alaskan Native issues. Prepared for the American Indian Policy Review Commission, the report is the work of representatives from task forces on tribal government, federal, state, and tribal…

  6. 40 CFR 408.50 - Applicability; description of the remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... remote Alaskan crab meat processing subcategory. 408.50 Section 408.50 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Crab Meat Processing Subcategory § 408.50 Applicability; description of the remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  7. 40 CFR 408.50 - Applicability; description of the remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... remote Alaskan crab meat processing subcategory. 408.50 Section 408.50 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Crab Meat Processing Subcategory § 408.50 Applicability; description of the remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  8. 40 CFR 408.50 - Applicability; description of the remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... remote Alaskan crab meat processing subcategory. 408.50 Section 408.50 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Crab Meat Processing Subcategory § 408.50 Applicability; description of the remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  9. 40 CFR 408.50 - Applicability; description of the remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... remote Alaskan crab meat processing subcategory. 408.50 Section 408.50 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Crab Meat Processing Subcategory § 408.50 Applicability; description of the remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  10. 40 CFR 408.50 - Applicability; description of the remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... remote Alaskan crab meat processing subcategory. 408.50 Section 408.50 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Remote Alaskan Crab Meat Processing Subcategory § 408.50 Applicability; description of the remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  11. 40 CFR 408.320 - Applicability; description of the non-Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-Alaskan herring fillet processing subcategory. 408.320 Section 408.320 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Herring Fillet Processing Subcategory § 408.320 Applicability; description of the non-Alaskan herring fillet processing subcategory. The provisions of this subpart...

  12. 40 CFR 408.320 - Applicability; description of the non-Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-Alaskan herring fillet processing subcategory. 408.320 Section 408.320 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Herring Fillet Processing Subcategory § 408.320 Applicability; description of the non-Alaskan herring fillet processing subcategory. The provisions of this subpart...

  13. 40 CFR 408.320 - Applicability; description of the non-Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Alaskan herring fillet processing subcategory. 408.320 Section 408.320 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Herring Fillet Processing Subcategory § 408.320 Applicability; description of the non-Alaskan herring fillet processing subcategory. The provisions of this subpart...

  14. 40 CFR 408.310 - Applicability; description of the Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Alaskan herring fillet processing subcategory. 408.310 Section 408.310 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Herring Fillet Processing Subcategory § 408.310 Applicability; description of the Alaskan herring fillet processing subcategory. The provisions of this subpart...

  15. 40 CFR 408.310 - Applicability; description of the Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Alaskan herring fillet processing subcategory. 408.310 Section 408.310 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Herring Fillet Processing Subcategory § 408.310 Applicability; description of the Alaskan herring fillet processing subcategory. The provisions of this subpart...

  16. 40 CFR 408.310 - Applicability; description of the Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Alaskan herring fillet processing subcategory. 408.310 Section 408.310 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Herring Fillet Processing Subcategory § 408.310 Applicability; description of the Alaskan herring fillet processing subcategory. The provisions of this subpart...

  17. 40 CFR 408.320 - Applicability; description of the non-Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-Alaskan herring fillet processing subcategory. 408.320 Section 408.320 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Herring Fillet Processing Subcategory § 408.320 Applicability; description of the non-Alaskan herring fillet processing subcategory. The provisions of this subpart...

  18. 40 CFR 408.310 - Applicability; description of the Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Alaskan herring fillet processing subcategory. 408.310 Section 408.310 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Herring Fillet Processing Subcategory § 408.310 Applicability; description of the Alaskan herring fillet processing subcategory. The provisions of this subpart...

  19. 40 CFR 408.310 - Applicability; description of the Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Alaskan herring fillet processing subcategory. 408.310 Section 408.310 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Herring Fillet Processing Subcategory § 408.310 Applicability; description of the Alaskan herring fillet processing subcategory. The provisions of this subpart...

  20. 40 CFR 408.320 - Applicability; description of the non-Alaskan herring fillet processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-Alaskan herring fillet processing subcategory. 408.320 Section 408.320 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Herring Fillet Processing Subcategory § 408.320 Applicability; description of the non-Alaskan herring fillet processing subcategory. The provisions of this subpart...

  1. 40 CFR 408.160 - Applicability; description of the Alaskan hand-butchered salmon processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Alaskan hand-butchered salmon processing subcategory. 408.160 Section 408.160 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Hand-Butchered Salmon Processing Subcategory § 408.160 Applicability; description of the Alaskan hand-butchered salmon processing subcategory. The provisions of this subpart...

  2. 40 CFR 408.170 - Applicability; description of the Alaskan mechanized salmon processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Alaskan mechanized salmon processing subcategory. 408.170 Section 408.170 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Mechanized Salmon Processing Subcategory § 408.170 Applicability; description of the Alaskan mechanized salmon processing subcategory. The provisions of this subpart...

  3. 40 CFR 408.160 - Applicability; description of the Alaskan hand-butchered salmon processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Alaskan hand-butchered salmon processing subcategory. 408.160 Section 408.160 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Hand-Butchered Salmon Processing Subcategory § 408.160 Applicability; description of the Alaskan hand-butchered salmon processing subcategory. The provisions of this subpart...

  4. 40 CFR 408.170 - Applicability; description of the Alaskan mechanized salmon processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Alaskan mechanized salmon processing subcategory. 408.170 Section 408.170 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Mechanized Salmon Processing Subcategory § 408.170 Applicability; description of the Alaskan mechanized salmon processing subcategory. The provisions of this subpart...

  5. 40 CFR 408.160 - Applicability; description of the Alaskan hand-butchered salmon processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Alaskan hand-butchered salmon processing subcategory. 408.160 Section 408.160 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Hand-Butchered Salmon Processing Subcategory § 408.160 Applicability; description of the Alaskan hand-butchered salmon processing subcategory. The provisions of this subpart...

  6. 40 CFR 408.160 - Applicability; description of the Alaskan hand-butchered salmon processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Alaskan hand-butchered salmon processing subcategory. 408.160 Section 408.160 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Hand-Butchered Salmon Processing Subcategory § 408.160 Applicability; description of the Alaskan hand-butchered salmon processing subcategory. The provisions of this subpart...

  7. 40 CFR 408.170 - Applicability; description of the Alaskan mechanized salmon processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Alaskan mechanized salmon processing subcategory. 408.170 Section 408.170 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Mechanized Salmon Processing Subcategory § 408.170 Applicability; description of the Alaskan mechanized salmon processing subcategory. The provisions of this subpart...

  8. 40 CFR 408.170 - Applicability; description of the Alaskan mechanized salmon processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Alaskan mechanized salmon processing subcategory. 408.170 Section 408.170 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Mechanized Salmon Processing Subcategory § 408.170 Applicability; description of the Alaskan mechanized salmon processing subcategory. The provisions of this subpart...

  9. 40 CFR 408.160 - Applicability; description of the Alaskan hand-butchered salmon processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Alaskan hand-butchered salmon processing subcategory. 408.160 Section 408.160 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Hand-Butchered Salmon Processing Subcategory § 408.160 Applicability; description of the Alaskan hand-butchered salmon processing subcategory. The provisions of this subpart...

  10. 40 CFR 408.170 - Applicability; description of the Alaskan mechanized salmon processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Alaskan mechanized salmon processing subcategory. 408.170 Section 408.170 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Alaskan Mechanized Salmon Processing Subcategory § 408.170 Applicability; description of the Alaskan mechanized salmon processing subcategory. The provisions of this subpart...

  11. Thematic mapper study of Alaskan ophiolites

    NASA Technical Reports Server (NTRS)

    Bird, John M.

    1988-01-01

    The two principle objectives of the project Thematic Mapper Study of Alaskan Ophiolites were to further develop techniques for producing geologic maps, and to study the tectonics of the ophiolite terrains of the Brooks Range and Ruby Geanticline of northern Alaska. Ophiolites, sections of oceanic lithosphere emplaced along island arcs and continental margins, are important to the understanding of mountain belt evolution. Ophiolites also provide an opportunity to study the structural, lithologic, and geochemical characteristics of ocean lithosphere, yielding a better understanding of the processes forming lithosphere. The first part of the report is a description of the methods and results of the TM mapping and gravity modeling. The second part includes papers being prepared for publication. These papers are the following: (1) an analysis of basalt spectral variations; (2) a study of basalt geochemical variations; (3) an examination of the cooling history of the ophiolites using radiometric data; (4) an analysis of shortening produced by thrusting during the Brooks Range orogeny; and (5) a study of an ophiolite using digital aeromagnetic and topographic data. Additional papers are in preparation.

  12. Evolution of geographical place and niche space: Patterns of diversification in the North American sedge (Cyperaceae) flora.

    PubMed

    Spalink, Daniel; Drew, Bryan T; Pace, Matthew C; Zaborsky, John G; Li, Pan; Cameron, Kenneth M; Givnish, Thomas J; Sytsma, Kenneth J

    2016-02-01

    The role of geography and ecology in speciation are often discussed in the context of phylogenetic niche conservatism (PNC), the propensity of lineages to retain ancestral niche related traits. However, a recent paradigm shift focuses instead on measuring divergence of these traits in conjunction with patterns of speciation. Under this framework, we analyzed the diversification of North America's third most diverse family, Cyperaceae ("sedges"), using a modified Parsimony Analysis of Endemicity approach to identify floristic regions and ordination statistics to quantify species distribution in a continuous manner. Utilizing over 200,000 georeferenced specimens, we characterized the geographical distribution and climatic and edaphic niche space occupied by each species. We constructed a supermatrix phylogeny of the North American sedge flora, aided in part by the sequencing of all sedges of Wisconsin, and employed a multifaceted approach to assess the role of geographical and ecological divergence on lineage diversification. In addition to measuring phylogenetic signal for these traits, we also measured pairwise phylogenetic distance of species within floristic regions, calculated rates of speciation, and tested for correlations of speciation rate to tempo of geographical and ecological evolution. Our analyses consistently show that evolutionarily related species tend to be geographically unrelated. Rates of geographical and ecological diversification are closely linked to tempo of speciation, and exploration of geographical place coincides with divergence in ecological niche space. We highlight the benefits of treating geography in a continuous manner, and stress the importance of employing a diverse suite of analytical approaches in testing hypotheses regarding the evolution of range and niche.

  13. Evolution of geographical place and niche space: Patterns of diversification in the North American sedge (Cyperaceae) flora.

    PubMed

    Spalink, Daniel; Drew, Bryan T; Pace, Matthew C; Zaborsky, John G; Li, Pan; Cameron, Kenneth M; Givnish, Thomas J; Sytsma, Kenneth J

    2016-02-01

    The role of geography and ecology in speciation are often discussed in the context of phylogenetic niche conservatism (PNC), the propensity of lineages to retain ancestral niche related traits. However, a recent paradigm shift focuses instead on measuring divergence of these traits in conjunction with patterns of speciation. Under this framework, we analyzed the diversification of North America's third most diverse family, Cyperaceae ("sedges"), using a modified Parsimony Analysis of Endemicity approach to identify floristic regions and ordination statistics to quantify species distribution in a continuous manner. Utilizing over 200,000 georeferenced specimens, we characterized the geographical distribution and climatic and edaphic niche space occupied by each species. We constructed a supermatrix phylogeny of the North American sedge flora, aided in part by the sequencing of all sedges of Wisconsin, and employed a multifaceted approach to assess the role of geographical and ecological divergence on lineage diversification. In addition to measuring phylogenetic signal for these traits, we also measured pairwise phylogenetic distance of species within floristic regions, calculated rates of speciation, and tested for correlations of speciation rate to tempo of geographical and ecological evolution. Our analyses consistently show that evolutionarily related species tend to be geographically unrelated. Rates of geographical and ecological diversification are closely linked to tempo of speciation, and exploration of geographical place coincides with divergence in ecological niche space. We highlight the benefits of treating geography in a continuous manner, and stress the importance of employing a diverse suite of analytical approaches in testing hypotheses regarding the evolution of range and niche. PMID:26702956

  14. A water-budget approach to restoring a sedge fen affected by diking and ditching

    USGS Publications Warehouse

    Wilcox, Douglas A.; Sweat, Michael J.; Carlson, Martha L.; Kowalski, Kurt P.

    2006-01-01

    A vast, ground-water-supported sedge fen in the Upper Peninsula of Michigan, USA was ditched in the early 1900s in a failed attempt to promote agriculture. Dikes were later constructed to impound seasonal sheet surface flows for waterfowl management. The US Fish and Wildlife Service, which now manages the wetland as part of Seney National Wildlife Refuge, sought to redirect water flows from impounded C-3 Pool to reduce erosion in downstream Walsh Ditch, reduce ground-water losses into the ditch, and restore sheet flows of surface water to the peatland. A water budget was developed for C-3 Pool, which serves as the central receiving and distribution body for water in the affected wetland. Surface-water inflows and outflows were measured in associated ditches and natural creeks, ground-water flows were estimated using a network of wells and piezometers, and precipitation and evaporation/evapotranspiration components were estimated using local meteorological data. Water budgets for the 1999 springtime peak flow period and the 1999 water year were used to estimate required releases of water from C-3 Pool via outlets other than Walsh Ditch and to guide other restoration activities. Refuge managers subsequently used these results to guide restoration efforts, including construction of earthen dams in Walsh Ditch upslope from the pool to stop surface flow, installation of new water-control structures to redirect surface water to sheet flow and natural creek channels, planning seasonal releases from C-3 Pool to avoid erosion in natural channels, stopping flow in downslope Walsh Ditch to reduce erosion, and using constructed earthen dams and natural beaver dams to flood the ditch channel below C-3 Pool. Interactions between ground water and surface water are critical for maintaining ecosystem processes in many wetlands, and management actions directed at restoring either ground- or surface-water flow patterns often affect both of these components of the water budget. This

  15. Strength and deformation characteristics of Alaskan offshore silts

    SciTech Connect

    Fleming, L.N.

    1985-01-01

    A comprehensive series of undrained shear tests were performed on representative samples of Alaskan silts in both the normally consolidated and overconsolidated state. The type of tests performed were triaxial compression and extension, torvane and miniature laboratory vane tests. It was found that the Alaskan silt exhibited dilative behavior during undrained shear. Also, the silt is highly anisotropic with respect to the stress-strain characteristics and the undrained shear strength. Sample disturbance reduced the measured strength in the unconsolidated undrained tests. The normalized strength parameter was shown to vary from one silt to another. The importance of evaluating the properties of each new silt deposit are described.

  16. Microhabitat differences impact phylogeographic concordance of codistributed species: genomic evidence in montane sedges (Carex L.) from the Rocky Mountains.

    PubMed

    Massatti, Rob; Knowles, L Lacey

    2014-10-01

    By selecting codistributed, closely related montane sedges from the Rocky Mountains that are similar in virtually all respects but one-their microhabitat affinities-we test predictions about how patterns of genetic variation are expected to differ between Carex nova, an inhabitant of wetlands, and Carex chalciolepis, an inhabitant of drier meadows, slopes, and ridges. Although contemporary populations of the taxa are similarly isolated, the distribution of glacial moraines suggests that their past population connectedness would have differed. Sampling of codistributed population pairs from different mountain ranges combined with the resolution provided by over 24,000 single nucleotide polymorphism loci supports microhabitat-mediated differences in the sedges' patterns of genetic variation that are consistent with their predicted differences in the degree of isolation of ancestral source populations. Our results highlight how microhabitat preferences may interact with glaciations to produce fundamental differences in the past distributions of presently codistributed species. We discuss the implications of these findings for generalizing the impacts of climate-induced distributional shifts for communities, as well as for the prospects of gaining insights about species-specific deterministic processes, not just deterministic community-level responses, from comparative phylogeographic study.

  17. Microhabitat differences impact phylogeographic concordance of codistributed species: genomic evidence in montane sedges (Carex L.) from the Rocky Mountains.

    PubMed

    Massatti, Rob; Knowles, L Lacey

    2014-10-01

    By selecting codistributed, closely related montane sedges from the Rocky Mountains that are similar in virtually all respects but one-their microhabitat affinities-we test predictions about how patterns of genetic variation are expected to differ between Carex nova, an inhabitant of wetlands, and Carex chalciolepis, an inhabitant of drier meadows, slopes, and ridges. Although contemporary populations of the taxa are similarly isolated, the distribution of glacial moraines suggests that their past population connectedness would have differed. Sampling of codistributed population pairs from different mountain ranges combined with the resolution provided by over 24,000 single nucleotide polymorphism loci supports microhabitat-mediated differences in the sedges' patterns of genetic variation that are consistent with their predicted differences in the degree of isolation of ancestral source populations. Our results highlight how microhabitat preferences may interact with glaciations to produce fundamental differences in the past distributions of presently codistributed species. We discuss the implications of these findings for generalizing the impacts of climate-induced distributional shifts for communities, as well as for the prospects of gaining insights about species-specific deterministic processes, not just deterministic community-level responses, from comparative phylogeographic study. PMID:25041894

  18. Policy Statements on Collection Development. A Compendium from Alaskan Libraries.

    ERIC Educational Resources Information Center

    McCabe, Carol, Ed.

    Developed as part of a statewide coordinated collection development effort, this document is a compendium of the narrative statements of collection development policies from 19 Alaskan university, public, school, and special libraries. Only the basic narrative plus any unique appendices are included for each policy, and some of the policies are…

  19. Village Science: A Resource Handbook for Rural Alaskan Teachers.

    ERIC Educational Resources Information Center

    Dick, Alan

    A resource handbook for rural Alaskan teachers covers village science, to make basic science concepts relevant to the physical environment in villages. Material is intended for use as filler for weeks that come up short on science materials, to provide stimulation for students who cannot see the relevance of science in their lives, and to help…

  20. Definition of Alaskan Aviation Training Requirements. Final Report.

    ERIC Educational Resources Information Center

    Mitchell, M. K.; And Others

    Because of high accident rates and the unique conditions faced in Arctic flying, a project was conducted to develop a training program for airline pilots flying over Alaska. Data were gathered, through the critical incident method in conjunction with traditional job-analysis procedures, about how experienced Alaskan pilots learned to cope with the…

  1. Rural Alaskan Schools: Educational Specifications. Reprinted September, 1971.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau. Office of Public Information and Publications.

    The educational specifications of facilities for rural Alaskan schools are given in this 1964 report. Alaska's 6 recognized geographic regions are briefly described with consideration to topography, climate, permafrost conditions, latitude position, and transportation difficulties which present problems in planning schools. Since the school design…

  2. Standard Implications: Alaskans Reflect on a Movement To Change Teaching.

    ERIC Educational Resources Information Center

    Calkins, Annie, Ed.; Christian, Scott, Ed.

    In this anthology, rural Alaskan English teachers in the Bread Loaf Rural Teacher Network describe their experiences implementing new state education standards while continuing their commitment to learner-centered and place-based practice. The book presents narratives about teaching grounded in knowledge and understanding of students and…

  3. RESIDUAL MUTAGENICITY OF THE ALASKAN OIL SPILL ORGANICS

    EPA Science Inventory

    RESIDUAL MUTAGENICITY OF THE ALASKAN OIL SPILL ORGANICS. L.D.

    The Exxon Valdez, on March 24, 1989, spilled approximately eleven million gallons of Prudhoe Bay crude oil into the waters of Prince William Sound. Approximately 300 miles of
    contaminated beach are potential...

  4. Effects of the Oil Spill on Alaskan Education.

    ERIC Educational Resources Information Center

    Oldaker, Lawrence Lee

    Oil-industry-produced revenues, help finance Alaskan state and local governmental services including education. Capital losses incurred by the Exxon Corporation and by commerical fisheries as a consequence of the Exxon Valdez oil spill caused an economic recession, the result being diminished financing for a number of governmental programs and…

  5. STARS (Secondary Training for Alaskan Rural Students): Science. Draft Copy.

    ERIC Educational Resources Information Center

    Shepard, Gary; Costello, Bill

    STARS (Secondary Training for Alaskan Rural Students) materials resulted from extensive rewriting of the Vocational Adult Secondary Training (VAST) materials produced by the British Columbia Department of Education, after those materials had been used with the 9th and 10th graders on Kodiak Island. Revision was done by teachers who had been using…

  6. Species coherence in the face of karyotype diversification in holocentric organisms: the case of a cytogenetically variable sedge (Carex scoparia, Cyperaceae)

    PubMed Central

    Escudero, Marcial; Weber, Jaime A.; Hipp, Andrew L.

    2013-01-01

    Background and Aims The sedge genus Carex, the most diversified angiosperm genus of the northern temperate zone, is renowned for its holocentric chromosomes and karyotype variability. The genus exhibits high variation in chromosome numbers both among and within species. Despite the possibility that this chromosome evolution may play a role in the high species diversity of Carex, population-level patterns of molecular and cytogenetic differentiation in the genus have not been extensively studied. Methods Microsatellite variation (11 loci, 461 individuals) and chromosomal diversity (82 individuals) were investigated in 22 Midwestern populations of the North American sedge Carex scoparia and two Northeastern populations. Key Results Among Midwestern populations, geographic distance is the most important predictor of genetic differentiation. Within populations, inbreeding is high and chromosome variation explains a significant component of genetic differentiation. Infrequent dispersal among populations separated by >100 km explains an important component of molecular genetic and cytogenetic diversity within populations. However, karyotype variation and correlation between genetic and chromosomal variation persist within populations even when putative migrants based on genetic data are excluded. Conclusions These findings demonstrate dispersal and genetic connectivity among widespread populations that differ in chromosome numbers, explaining the phenomenon of genetic coherence in this karyotypically diverse sedge species. More generally, the study suggests that traditional sedge taxonomic boundaries demarcate good species even when those species encompass a high range of chromosomal diversity. This finding is important evidence as we work to document the limits and drivers of biodiversity in one of the world's largest angiosperm genera. PMID:23723260

  7. Sex- and age-related differences in the timing and body condition of migrating Reed Warblers Acrocephalus scirpaceus and Sedge Warblers Acrocephalus schoenobaenus

    NASA Astrophysics Data System (ADS)

    Jakubas, Dariusz; Wojczulanis-Jakubas, Katarzyna

    2010-05-01

    The migration strategies of birds may vary strongly between species and also between age and/or sex groups. We studied the autumn migration and body condition of molecularly sexed Reed Warblers Acrocephalus scirpaceus and Sedge Warblers Acrocephalus schoenobaenus (211 and 208 ind., respectively) at a stopover site on Lake Druzno, Northern Poland, in 2008. Immature male Reed Warblers were caught significantly later than females (median dates 9 days later), but in the Sedge Warbler, both sexes of immatures migrated at about the same time. Adult males and females of both species did not differ in their time of migration. Adult and immature males of both species were larger (wing length and body mass) than females. In both species, fat reserves were similar in both sexes of both age classes. Adults of both sexes of Reed and Sedge Warbler were generally caught earlier than immatures. In both species, the body mass and fat reserves of immatures were generally less than in adults. The autumn protogyny of immature Reed Warblers may allow smaller females to limit competition with bigger males during migration and at the wintering grounds. In the Sedge Warbler, which tends to match its migration to peak of occurrence of superabundant food at stopover sites, both sexes gain an advantage from migrating at the same time. Since part of the measured wing length variation in both species was explained by sex differences, temporal trends in wing length recorded at stopover sites should be interpreted with caution.

  8. Sixteen-year stimulation of sedge density by elevated CO2 reaches 100% and is salt-stress enhanced.

    NASA Astrophysics Data System (ADS)

    Rasse, D. P.; Drake, B. G.

    2003-12-01

    Increased atmospheric CO2 concentration produces a short-term stimulation of plant growth across terrestrial ecosystems. However, the long-term response remains uncertain and is thought to depend on environmental constraints. In the longest experiment on natural ecosystem response to elevated CO2, we observed for the wetland sedge Scirpus olneyi that the shoot-density stimulation by elevated CO2 increased from 16% during the first four years to more than 100% in the 16th year. While most of the inter-annual variability of the stimulation was explained by this steady increase with time (r2 = 0.89), the residuals of this variability were positively correlated with the salinity of the marsh (r2 = 0.44). These results demonstrate that the inter-annual variability of plant response to elevated CO2 is coupled to environmental stress and indicate that experiments based on more than a decade of measurements are necessary to ascertain such effects.

  9. Hereditary encephalomyelopathy and polyneuropathy in an Alaskan husky.

    PubMed

    Wakshlag, J J; de Lahunta, A

    2009-12-01

    An Alaskan husky puppy was examined for a neurologic disease which began at six weeks of age with generalised paresis that progressed resulting in recumbency by 18 weeks. Thoracic limbs primarily exhibited lower motor neuron signs that included distal muscle atrophy and persistent elbow and carpal flexion that resisted manual extension. Pelvic limb signs primarily exhibited upper motor neuron and general proprioceptive deficits, but also included lower motor neuron signs. Abnormal vocalisation suggested a laryngeal paresis. Histopathologic lesions included a diffuse axonopathy and secondary demyelination in the nerves of the limbs and larynx and a similar bilaterally symmetrical degeneration in the spinal cord white matter suggestive of a dying back axonopathy. In addition, a degenerative process was present in nuclei in the brain stem and cerebellum. Recognition of this disease through clinical and pathologic examination in other related Alaskan Huskies suggested an autosomal recessive inherited disorder.

  10. Productivity of wet soils: Biomass of cultivated and natural vegetation

    SciTech Connect

    Johnston, C.A.

    1988-12-01

    Wet soils, soils which have agronomic limitations because of excess water, comprise 105 million acres of non-federal land in the conterminous United States. Wet soils which support hydrophytic plants are ''wetlands'', and are some of the most productive natural ecosystems in the world. When both above- and belowground productivity are considered, cattail (Typha latifolia) is the most productive temperate wetland species (26.4 Mg/ha/year). Both cattail and reed (Phragmites australis) have aboveground productivities of about 13 Mg/ha/year. Although average aboveground yields of reed canarygrass (Phalaris arundinacea) are lower (9.5 Mg/ha/year), techniques for its establishment and cultivation are well-developed. Other herbaceous wetland species which show promise as biomass crops include sedge (Carex spp.), river bulrush (Scirpus fluviatilis) and prairie cordgrass (Spartina pectinata). About 40% of wet soils in the conterminous US are currently cultivated, and they produce one-quarter of the major US crops. Most of this land is artificially drained for crops such as corn, soybeans, and vegetables. US wetlands are drained for agriculture at the rate of 223,000 ha/yr. Paddies flooded with water are used to grow rice, cranberries, and wild rice. Forage and live sphagnum moss are products of undrained wetlands. A number of federal and state regulations apply to the draining or irrigation of wetlands, but most do not seriously restrict their use for agriculture. 320 refs., 36 tabs.

  11. Wetting or non-wetting liquid?

    NASA Astrophysics Data System (ADS)

    Karmakov, Iordan

    2000-11-01

    What factors determine whether or not a particular liquid will wet a particular surface? Is it possible for a meniscus in a capillary to become convex from concave? What would you have to do to flatten it out? In university courses in physics there is often a lack of example or comment concerning the influence of temperature on the characteristics of liquid surface tension. For example, would temperature be a factor in changing wetting? This article describes an experiment that illustrates the conversion of isopropyl alcohol from a wetting state to a non-wetting state as a result of the influence of temperature on the characteristics of the liquid.

  12. Revegetation of Alaskan coal mine spoils. Progress report

    SciTech Connect

    Mitchell, W W; Mitchell, G A; McKendrick, J D

    1980-05-23

    Activities initiated after the start of the revegetation project on Alaskan coal mine spoils on September 1, 1979 have consisted mainly of some fall plantings (dormant seedings) and soil and coal spoil samplings and analyses. Because of the late summer start for the project, only a limited amount of field work could be initiated in plant material studies. This consisted of a fall planting at the Usibelli mine site at Healy in interior Alaska. The planting was intended to test the efficacy of seeding in the frost period following the growing season, requiring the seed to remain dormant over winter and to germinate when conditions become favorable in late spring. It also was intended as a comparison of a number of different grasses. Thirty entries were seeded in three replications. Fifteen species of grasses and a clover were included in the trial. The site provided for the trial was on overburden material along a streambed. Among the entries were eight cultivars of introduced grasses, five cultivars of native Alaskan germplasm, one introduced clover cultivar, and sixteen experimental grasses mainly of Alaskan origin.

  13. 40 CFR 408.210 - Applicability; description of the non-Alaskan conventional bottom fish processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-Alaskan conventional bottom fish processing subcategory. 408.210 Section 408.210 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Conventional Bottom Fish Processing Subcategory § 408.210 Applicability; description of the non-Alaskan conventional bottom fish processing subcategory. The provisions...

  14. 40 CFR 408.210 - Applicability; description of the non-Alaskan conventional bottom fish processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-Alaskan conventional bottom fish processing subcategory. 408.210 Section 408.210 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Conventional Bottom Fish Processing Subcategory § 408.210 Applicability; description of the non-Alaskan conventional bottom fish processing subcategory. The provisions...

  15. 40 CFR 408.210 - Applicability; description of the non-Alaskan conventional bottom fish processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-Alaskan conventional bottom fish processing subcategory. 408.210 Section 408.210 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Conventional Bottom Fish Processing Subcategory § 408.210 Applicability; description of the non-Alaskan conventional bottom fish processing subcategory. The provisions...

  16. 40 CFR 408.210 - Applicability; description of the non-Alaskan conventional bottom fish processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-Alaskan conventional bottom fish processing subcategory. 408.210 Section 408.210 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Conventional Bottom Fish Processing Subcategory § 408.210 Applicability; description of the non-Alaskan conventional bottom fish processing subcategory. The provisions...

  17. 40 CFR 408.210 - Applicability; description of the non-Alaskan conventional bottom fish processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Alaskan conventional bottom fish processing subcategory. 408.210 Section 408.210 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Conventional Bottom Fish Processing Subcategory § 408.210 Applicability; description of the non-Alaskan conventional bottom fish processing subcategory. The provisions...

  18. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  19. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  20. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  1. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  2. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  3. 40 CFR 408.60 - Applicability; description of the non-remote Alaskan whole crab and crab section processing...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-remote Alaskan whole crab and crab section processing subcategory. 408.60 Section 408.60 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.60 Applicability; description of the non-remote Alaskan whole crab and crab...

  4. 40 CFR 408.40 - Applicability; description of the non-remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-remote Alaskan crab meat processing subcategory. 408.40 Section 408.40 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Crab Meat Processing Subcategory § 408.40 Applicability; description of the non-remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  5. 40 CFR 408.70 - Applicability; description of the remote Alaskan whole crab and crab section processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... remote Alaskan whole crab and crab section processing subcategory. 408.70 Section 408.70 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.70 Applicability; description of the remote Alaskan whole crab and crab section...

  6. 40 CFR 408.60 - Applicability; description of the non-remote Alaskan whole crab and crab section processing...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-remote Alaskan whole crab and crab section processing subcategory. 408.60 Section 408.60 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.60 Applicability; description of the non-remote Alaskan whole crab and crab...

  7. 40 CFR 408.70 - Applicability; description of the remote Alaskan whole crab and crab section processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... remote Alaskan whole crab and crab section processing subcategory. 408.70 Section 408.70 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.70 Applicability; description of the remote Alaskan whole crab and crab section...

  8. 40 CFR 408.60 - Applicability; description of the non-remote Alaskan whole crab and crab section processing...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-remote Alaskan whole crab and crab section processing subcategory. 408.60 Section 408.60 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.60 Applicability; description of the non-remote Alaskan whole crab and crab...

  9. 40 CFR 408.70 - Applicability; description of the remote Alaskan whole crab and crab section processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... remote Alaskan whole crab and crab section processing subcategory. 408.70 Section 408.70 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.70 Applicability; description of the remote Alaskan whole crab and crab section...

  10. 40 CFR 408.60 - Applicability; description of the non-remote Alaskan whole crab and crab section processing...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-remote Alaskan whole crab and crab section processing subcategory. 408.60 Section 408.60 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.60 Applicability; description of the non-remote Alaskan whole crab and crab...

  11. 40 CFR 408.60 - Applicability; description of the non-remote Alaskan whole crab and crab section processing...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-remote Alaskan whole crab and crab section processing subcategory. 408.60 Section 408.60 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.60 Applicability; description of the non-remote Alaskan whole crab and crab...

  12. 40 CFR 408.70 - Applicability; description of the remote Alaskan whole crab and crab section processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... remote Alaskan whole crab and crab section processing subcategory. 408.70 Section 408.70 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.70 Applicability; description of the remote Alaskan whole crab and crab section...

  13. 40 CFR 408.70 - Applicability; description of the remote Alaskan whole crab and crab section processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... remote Alaskan whole crab and crab section processing subcategory. 408.70 Section 408.70 Protection of... SEAFOOD PROCESSING POINT SOURCE CATEGORY Remote Alaskan Whole Crab and Crab Section Processing Subcategory § 408.70 Applicability; description of the remote Alaskan whole crab and crab section...

  14. 40 CFR 408.40 - Applicability; description of the non-remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-remote Alaskan crab meat processing subcategory. 408.40 Section 408.40 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Crab Meat Processing Subcategory § 408.40 Applicability; description of the non-remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  15. 40 CFR 408.40 - Applicability; description of the non-remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-remote Alaskan crab meat processing subcategory. 408.40 Section 408.40 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Crab Meat Processing Subcategory § 408.40 Applicability; description of the non-remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  16. 40 CFR 408.40 - Applicability; description of the non-remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-remote Alaskan crab meat processing subcategory. 408.40 Section 408.40 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Crab Meat Processing Subcategory § 408.40 Applicability; description of the non-remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  17. 40 CFR 408.40 - Applicability; description of the non-remote Alaskan crab meat processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-remote Alaskan crab meat processing subcategory. 408.40 Section 408.40 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Remote Alaskan Crab Meat Processing Subcategory § 408.40 Applicability; description of the non-remote Alaskan crab meat processing subcategory. The provisions of this subpart...

  18. 25 CFR 243.11 - Are transfers of Alaskan reindeer that occurred before issuance of this part valid?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Are transfers of Alaskan reindeer that occurred before... INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.11 Are transfers of Alaskan reindeer that occurred before issuance of this part valid? All transfers of live Alaskan reindeer or reindeer products that...

  19. 25 CFR 243.11 - Are transfers of Alaskan reindeer that occurred before issuance of this part valid?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Are transfers of Alaskan reindeer that occurred before... INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.11 Are transfers of Alaskan reindeer that occurred before issuance of this part valid? All transfers of live Alaskan reindeer or reindeer products that...

  20. 25 CFR 243.11 - Are transfers of Alaskan reindeer that occurred before issuance of this part valid?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Are transfers of Alaskan reindeer that occurred before... INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.11 Are transfers of Alaskan reindeer that occurred before issuance of this part valid? All transfers of live Alaskan reindeer or reindeer products that...

  1. 25 CFR 243.11 - Are transfers of Alaskan reindeer that occurred before issuance of this part valid?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Are transfers of Alaskan reindeer that occurred before... INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.11 Are transfers of Alaskan reindeer that occurred before issuance of this part valid? All transfers of live Alaskan reindeer or reindeer products that...

  2. 25 CFR 243.11 - Are transfers of Alaskan reindeer that occurred before issuance of this part valid?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Are transfers of Alaskan reindeer that occurred before... INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.11 Are transfers of Alaskan reindeer that occurred before issuance of this part valid? All transfers of live Alaskan reindeer or reindeer products that...

  3. Cool, wet conditions late in the Younger Dryas in semi-arid New Mexico

    NASA Astrophysics Data System (ADS)

    Hall, Stephen A.; Penner, William L.; Palacios-Fest, Manuel R.; Metcalf, Artie L.; Smith, Susan J.

    2012-01-01

    A thick alluvial sequence in central New Mexico contains the Scholle wet meadow deposit that traces upstream to a paleospring. The wet meadow sediments contain an abundant fauna of twenty-one species of freshwater and terrestrial mollusks and ten species of ostracodes. The mollusks and ostracodes are indicative of a local high alluvial water table with spring-supported perennial flow but without standing water. Pollen analysis documents shrub grassland vegetation with sedges, willow, and alder in a riparian community. Stable carbon isotopes from the wet meadow sediments have δ13C values ranging from - 22.8 to - 23.3‰, indicating that 80% of the organic carbon in the sediment is derived from C3 species. The wet meadow deposit is AMS dated 10,400 to 9700 14C yr BP, corresponding to 12,300 to 11,100 cal yr BP and overlapping in time with the Younger Dryas event (YD). The wet meadow became active about 500 yr after the beginning of the YD and persisted 400 yr after the YD ended. The Scholle wet meadow is the only record of perennial flow and high water table conditions in the Abo Arroyo drainage basin during the past 13 ka.

  4. Enuresis (Bed-Wetting)

    MedlinePlus

    ... their development. Bed-wetting is more common among boys than girls. What causes bed-wetting? A number of things ... valves in boys or in the ureter in girls or boys Abnormalities in the spinal cord A small bladder ...

  5. 25 CFR 243.9 - Who may inherit live Alaskan reindeer and by what means?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... provisions of 43 CFR part 4, subpart D. During the pendency of such a proceeding, the authority to assume control over the affected Alaskan reindeer pursuant to 43 CFR 4.270 may be exercised by the Alaska... 25 Indians 1 2011-04-01 2011-04-01 false Who may inherit live Alaskan reindeer and by what...

  6. 25 CFR 243.9 - Who may inherit live Alaskan reindeer and by what means?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... provisions of 43 CFR part 4, subpart D. During the pendency of such a proceeding, the authority to assume control over the affected Alaskan reindeer pursuant to 43 CFR 4.270 may be exercised by the Alaska... 25 Indians 1 2014-04-01 2014-04-01 false Who may inherit live Alaskan reindeer and by what...

  7. 25 CFR 243.4 - Who can own or possess Alaskan reindeer?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Who can own or possess Alaskan reindeer? 243.4 Section 243.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.4 Who can own or possess Alaskan reindeer? (a) Only Alaska Natives, organizations of...

  8. 25 CFR 243.9 - Who may inherit live Alaskan reindeer and by what means?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... provisions of 43 CFR part 4, subpart D. During the pendency of such a proceeding, the authority to assume control over the affected Alaskan reindeer pursuant to 43 CFR 4.270 may be exercised by the Alaska... 25 Indians 1 2012-04-01 2011-04-01 true Who may inherit live Alaskan reindeer and by what...

  9. 25 CFR 243.4 - Who can own or possess Alaskan reindeer?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Who can own or possess Alaskan reindeer? 243.4 Section 243.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.4 Who can own or possess Alaskan reindeer? (a) Only Alaska Natives, organizations of...

  10. 25 CFR 243.4 - Who can own or possess Alaskan reindeer?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Who can own or possess Alaskan reindeer? 243.4 Section 243.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.4 Who can own or possess Alaskan reindeer? (a) Only Alaska Natives, organizations of...

  11. 25 CFR 243.4 - Who can own or possess Alaskan reindeer?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Who can own or possess Alaskan reindeer? 243.4 Section 243.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.4 Who can own or possess Alaskan reindeer? (a) Only Alaska Natives, organizations of...

  12. 25 CFR 243.9 - Who may inherit live Alaskan reindeer and by what means?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... provisions of 43 CFR part 4, subpart D. During the pendency of such a proceeding, the authority to assume control over the affected Alaskan reindeer pursuant to 43 CFR 4.270 may be exercised by the Alaska... 25 Indians 1 2013-04-01 2013-04-01 false Who may inherit live Alaskan reindeer and by what...

  13. 25 CFR 243.4 - Who can own or possess Alaskan reindeer?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Who can own or possess Alaskan reindeer? 243.4 Section 243.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE REINDEER IN ALASKA § 243.4 Who can own or possess Alaskan reindeer? (a) Only Alaska Natives, organizations of...

  14. An Authentic Voice in the Technocratic Wilderness: Alaskan Natives and the "Tundra Times."

    ERIC Educational Resources Information Center

    Daley, Patrick; James, Beverly

    1986-01-01

    Examines a pair of critical challenges to the cultural integrity of Alaskan Natives around 1960 as pivotal episodes in the process of native resistance to U. S. dominance. Historically evaluates the fragility of native culture in terms of the political, scientific, and economic interests expressed in the mainstream Alaskan press, particularly the…

  15. 25 CFR 243.9 - Who may inherit live Alaskan reindeer and by what means?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... provisions of 43 CFR part 4, subpart D. During the pendency of such a proceeding, the authority to assume control over the affected Alaskan reindeer pursuant to 43 CFR 4.270 may be exercised by the Alaska... live Alaskan reindeer may pass to the deceased owner's Native heirs by descent or devise. (b) In...

  16. Field note: phytoremediation of petroleum sludge contaminated field using sedge species, Cyperus rotundus (Linn.) and Cyperus brevifolius (Rottb.) Hassk.

    PubMed

    Basumatary, Budhadev; Saikia, Rubul; Das, Hamendra Chandra; Bordoloi, Sabitry

    2013-01-01

    The aim of this study was to degrade total petroleum hydrocarbon (TPH) in a petroleum sludge contaminated site (initial TPH concentration of 65,000-75,000 mg kg(-1)) with two native sedge species namely Cyperus rotundus (Linn.) and Cyperus brevifolius (Rottb.) Hassk. Fertilized and unfertilized treatments were maintained separately to record the influence of fertilizer in TPH degradation. The average biomass production (twenty plants from each treatment) of C. rotundus was 345.5 g and that of C. brevifolius was 250.6 g in fertilized soil during 360 days. Decrease in soil TPH concentration was higher in fertilized soil (75% for C. rotundus and 64% for C. brevifolius) than in unfertilized soil (36% for C. rotundus and 32% for C. brevifolius). In unvegetated treatments, decrease in soil TPH concentration in fertilized (12%) and unfertilized soil (8%) can be attributed to natural attenuation and microbial degradation. TPH accumulation in roots and shoots was significantly higher in fertilized soil in comparison to unfertilized soils (p < 0.05). Most probable number (MPN) in planted treatments was significantly higher than in unplanted treatments (p < 0.05). PMID:23819282

  17. (Alaskan commodities irradiation project: An options analysis study)

    SciTech Connect

    Zarling, J.P.; Swanson, R.B.; Logan, R.R.; Das, D.K.; Lewis, C.E.; Workman, W.G.; Tumeo, M.A.; Hok, C.I.; Birklind, C.A.; Bennett, F.L. . Inst. of Northern Engineering)

    1989-09-01

    The ninety-ninth US Congress commissioned a six-state food irradiation research and development program to evaluate the commercial potential of this technology. Hawaii, Washington, Iowa, Oklahoma and Florida as well as Alaska have participated in the national program; various food products including fishery products, red meats, tropical and citrus fruits and vegetables have been studied. The purpose of the Alaskan study was to review and evaluate those factors related to the technical and economic feasibility of an irradiator in Alaska. This options analysis study will serve as a basis for determining the state's further involvement in the development of food irradiation technology.

  18. Influence of biomass harvesting on fluxes of CO2 CH4 and N2O for a sedge fen in south-west Belarus

    NASA Astrophysics Data System (ADS)

    Burlo, A.; Minke, M.; Chuvashova, H.; Yarmashuk, T.; Augustin, J.; Thiele, A.; Tichonov, V.; Liashchynskaya, N.; Narkevitch, I.

    2012-04-01

    Until now, it is usual to drain a peatland to be able to use it economically. The consequences are a progressive peat loss and a negative climate impact caused by a strong emission of the greenhouse gases CO2 and N2O (Droesler et al., 2008). To avoid these negative effects of the peatland use, the concept of the so-called Paludiculture was developed. This is the harvest of plant biomass on wet and rewetted peatlands (Wichtmann & Joosten 2007). However, there is only few and contradictory information about the actual effect of the Paludiculture on the greenhouse gas fluxes, the peat carbon budget, and the climate balance so far. Therefore, we investigated the influence of late mowing on a sedge fen in the Paliessie region in SW Belarus. The site is characterized by Carex nigra, Carex rostrata, Calamagrostis canescens, Potentilla palustris, Drepanocladus aduncus and Rhizomnium punctatum and a mean water level close to the surface. The investigation covers two variants: Without use (control), and the removal of the aboveground biomass in late autumn. For every variant, we installed three soil collars distributed randomly as a base for the gas flux measurements. Since August 2010 the CO2, CH4 and N2O exchange rates are measured by the closed chamber approach of Droesler (2005). The first harvest of plant biomass was on 17th of November 2010. It turned out, that the single gas fluxes are influenced very differently by the biomass removal. In case of the CH4 a noticeable impact of mowing became evident directly after melting of the ice layer in spring 2011, when the emissions at the harvested plots for nearly doubled those from the control on two measurement campaigns. The N2O fluxes were very week but these are according to tendency lower on the harvest variant all the time. However, the ecosystem respiration did not show any clear reaction on the mowing at all. Furthermore, we will report about the effects of the biomass removal on the current net CO2 exchange, the

  19. PREFACE: Dynamics of wetting Dynamics of wetting

    NASA Astrophysics Data System (ADS)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  20. Analysis of Alaskan burn severity patterns using remotely sensed data

    USGS Publications Warehouse

    Duffy, P.A.; Epting, J.; Graham, J.M.; Rupp, T.S.; McGuire, A.D.

    2007-01-01

    Wildland fire is the dominant large-scale disturbance mechanism in the Alaskan boreal forest, and it strongly influences forest structure and function. In this research, patterns of burn severity in the Alaskan boreal forest are characterised using 24 fires. First, the relationship between burn severity and area burned is quantified using a linear regression. Second, the spatial correlation of burn severity as a function of topography is modelled using a variogram analysis. Finally, the relationship between vegetation type and spatial patterns of burn severity is quantified using linear models where variograms account for spatial correlation. These results show that: 1) average burn severity increases with the natural logarithm of the area of the wildfire, 2) burn severity is more variable in topographically complex landscapes than in flat landscapes, and 3) there is a significant relationship between burn severity and vegetation type in flat landscapes but not in topographically complex landscapes. These results strengthen the argument that differential flammability of vegetation exists in some boreal landscapes of Alaska. Additionally, these results suggest that through feedbacks between vegetation and burn severity, the distribution of forest vegetation through time is likely more stable in flat terrain than it is in areas with more complex topography. ?? IAWF 2007.

  1. Phlorotannins from Alaskan seaweed inhibit carbolytic enzyme activity.

    PubMed

    Kellogg, Joshua; Grace, Mary H; Lila, Mary Ann

    2014-10-22

    Global incidence of type 2 diabetes has escalated over the past few decades, necessitating a continued search for natural sources of enzyme inhibitors to offset postprandial hyperglycemia. The objective of this study was to evaluate coastal Alaskan seaweed inhibition of α-glucosidase and α-amylase, two carbolytic enzymes involved in serum glucose regulation. Of the six species initially screened, the brown seaweeds Fucus distichus and Alaria marginata possessed the strongest inhibitory effects. F. distichus fractions were potent mixed-mode inhibitors of α-glucosidase and α-amylase, with IC50 values of 0.89 and 13.9 μg/mL, respectively; significantly more efficacious than the pharmaceutical acarbose (IC50 of 112.0 and 137.8 μg/mL, respectively). The activity of F. distichus fractions was associated with phlorotannin oligomers. Normal-phase liquid chromatography-mass spectrometry (NPLC-MS) was employed to characterize individual oligomers. Accurate masses and fragmentation patterns confirmed the presence of fucophloroethol structures with degrees of polymerization from 3 to 18 monomer units. These findings suggest that coastal Alaskan seaweeds are sources of α-glucosidase and α-amylase inhibitory phlorotannins, and thus have potential to limit the release of sugar from carbohydrates and thus alleviate postprandial hyperglycemia.

  2. Reanalysis of the USGS Alaskan benchmark glacier dataset

    NASA Astrophysics Data System (ADS)

    van Beusekom, A. E.; O'Neel, S.; March, R. S.; Sass, L. C.

    2010-12-01

    Resolving the relationship between glacier surface-forcing (climate) and glacier geometry changes is accomplished through mass-balance estimates which can be made with remote sensing methods or field-based observations. The small scale of Alaskan glaciers has prevented remote sensing methods until recently, and field data are essential for validating new techniques. Field data provide the only long duration record that can be studied with respect to climate. The United States Geological Survey has maintained a 44-year mass-balance program at Alaska’s Gulkana Glacier and Wolverine Glacier. We have reanalyzed the Alaskan benchmark glaciers mass balance time series so that all data are treated similarly and systematically. Both glaciers are undergoing sustained mass loss with an increasing rate in recent years. However, the magnitude of the calculated loss depends on the number and location of the data collection sites. We explore the sensitivity of the glacier-wide balance estimates to the method of integration used on the necessarily point data. The robustness of the balance is strengthened with use of independent photogrammetric measurements.

  3. Changes in the structure and function of northern Alaskan ecosystems when considering variable leaf-out times across groupings of species in a dynamic vegetation model.

    PubMed

    Euskirchen, Eugénie S; Carman, Tobey B; McGuire, A David

    2014-03-01

    The phenology of arctic ecosystems is driven primarily by abiotic forces, with temperature acting as the main determinant of growing season onset and leaf budburst in the spring. However, while the plant species in arctic ecosystems require differing amounts of accumulated heat for leaf-out, dynamic vegetation models simulated over regional to global scales typically assume some average leaf-out for all of the species within an ecosystem. Here, we make use of air temperature records and observations of spring leaf phenology collected across dominant groupings of species (dwarf birch shrubs, willow shrubs, other deciduous shrubs, grasses, sedges, and forbs) in arctic and boreal ecosystems in Alaska. We then parameterize a dynamic vegetation model based on these data for four types of tundra ecosystems (heath tundra, shrub tundra, wet sedge tundra, and tussock tundra), as well as ecotonal boreal white spruce forest, and perform model simulations for the years 1970-2100. Over the course of the model simulations, we found changes in ecosystem composition under this new phenology algorithm compared with simulations with the previous phenology algorithm. These changes were the result of the differential timing of leaf-out, as well as the ability for the groupings of species to compete for nitrogen and light availability. Regionally, there were differences in the trends of the carbon pools and fluxes between the new phenology algorithm and the previous phenology algorithm, although these differences depended on the future climate scenario. These findings indicate the importance of leaf phenology data collection by species and across the various ecosystem types within the highly heterogeneous Arctic landscape, and that dynamic vegetation models should consider variation in leaf-out by groupings of species within these ecosystems to make more accurate projections of future plant distributions and carbon cycling in Arctic regions. PMID:24105949

  4. Changes in the structure and function of northern Alaskan ecosystems when considering variable leaf-out times across groupings of species in a dynamic vegetation model.

    PubMed

    Euskirchen, Eugénie S; Carman, Tobey B; McGuire, A David

    2014-03-01

    The phenology of arctic ecosystems is driven primarily by abiotic forces, with temperature acting as the main determinant of growing season onset and leaf budburst in the spring. However, while the plant species in arctic ecosystems require differing amounts of accumulated heat for leaf-out, dynamic vegetation models simulated over regional to global scales typically assume some average leaf-out for all of the species within an ecosystem. Here, we make use of air temperature records and observations of spring leaf phenology collected across dominant groupings of species (dwarf birch shrubs, willow shrubs, other deciduous shrubs, grasses, sedges, and forbs) in arctic and boreal ecosystems in Alaska. We then parameterize a dynamic vegetation model based on these data for four types of tundra ecosystems (heath tundra, shrub tundra, wet sedge tundra, and tussock tundra), as well as ecotonal boreal white spruce forest, and perform model simulations for the years 1970-2100. Over the course of the model simulations, we found changes in ecosystem composition under this new phenology algorithm compared with simulations with the previous phenology algorithm. These changes were the result of the differential timing of leaf-out, as well as the ability for the groupings of species to compete for nitrogen and light availability. Regionally, there were differences in the trends of the carbon pools and fluxes between the new phenology algorithm and the previous phenology algorithm, although these differences depended on the future climate scenario. These findings indicate the importance of leaf phenology data collection by species and across the various ecosystem types within the highly heterogeneous Arctic landscape, and that dynamic vegetation models should consider variation in leaf-out by groupings of species within these ecosystems to make more accurate projections of future plant distributions and carbon cycling in Arctic regions.

  5. Changes in the structure and function of northern Alaskan ecosystems when considering variable leaf-out times across groupings of species in a dynamic vegetation model

    USGS Publications Warehouse

    Euskirchen, E.S.; Carman, T.B.; McGuire, Anthony David

    2013-01-01

    The phenology of arctic ecosystems is driven primarily by abiotic forces, with temperature acting as the main determinant of growing season onset and leaf budburst in the spring. However, while the plant species in arctic ecosystems require differing amounts of accumulated heat for leaf-out, dynamic vegetation models simulated over regional to global scales typically assume some average leaf-out for all of the species within an ecosystem. Here, we make use of air temperature records and observations of spring leaf phenology collected across dominant groupings of species (dwarf birch shrubs, willow shrubs, other deciduous shrubs, grasses, sedges, and forbs) in arctic and boreal ecosystems in Alaska. We then parameterize a dynamic vegetation model based on these data for four types of tundra ecosystems (heath tundra, shrub tundra, wet sedge tundra, and tussock tundra), as well as ecotonal boreal white spruce forest, and perform model simulations for the years 1970 -2100. Over the course of the model simulations, we found changes in ecosystem composition under this new phenology algorithm compared to simulations with the previous phenology algorithm. These changes were the result of the differential timing of leaf-out, as well as the ability for the groupings of species to compete for nitrogen and light availability. Regionally, there were differences in the trends of the carbon pools and fluxes between the new phenology algorithm and the previous phenology algorithm, although these differences depended on the future climate scenario. These findings indicate the importance of leaf phenology data collection by species and across the various ecosystem types within the highly heterogeneous Arctic landscape, and that dynamic vegetation models should consider variation in leaf-out by groupings of species within these ecosystems to make more accurate projections of future plant distributions and carbon cycling in Arctic regions.

  6. Guide to wet scrubbers

    SciTech Connect

    Toy, D.A.

    1983-10-01

    The use of wet scrubbers for control of air pollution has gained wide acceptance throughout industry in the last two decades. Many plants have turned to wet scrubber technology to help reduce their discharge volumes and to help them comply with future regulations. There are four major classifications: centrifugal, venturi, packed column, and mist eliminators. Over 200 manufacturers of wet scrubbers were surveyed and their systems are listed to assist readers in selecting the proper system for a particular application.

  7. Contrasting patterns of clonality and fine-scale genetic structure in two rare sedges with differing geographic distributions

    PubMed Central

    Binks, R M; Millar, M A; Byrne, M

    2015-01-01

    For plants with mixed reproductive capabilities, asexual reproduction is more frequent in rare species and is considered a strategy for persistence when sexual recruitment is limited. We investigate whether asexual reproduction contributes to the persistence of two co-occurring, rare sedges that both experience irregular seed set and if their differing geographic distributions have a role in the relative contribution of clonality. Genotypic richness was high (R=0.889±0.02) across the clustered populations of Lepidosperma sp. Mt Caudan and, where detected, clonal patches were small, both in ramet numbers (⩽3 ramets/genet) and physical size (1.3±0.1 m). In contrast, genotypic richness was lower in the isolated L. sp. Parker Range populations, albeit more variable (R=0.437±0.13), with genets as large as 17 ramets and up to 5.8 m in size. Aggregated clonal growth generated significant fine-scale genetic structure in both species but to a greater spatial extent and with additional genet-level structure in L. sp. Parker Range that is likely due to restricted seed dispersal. Despite both species being rare, asexual reproduction clearly has a more important role in the persistence of L. sp. Parker Range than L. sp. Mt Caudan. This is consistent with our prediction that limitations to sexual reproduction, via geographic isolation to effective gene exchange, can lead to greater contributions of asexual reproduction. These results demonstrate the role of population isolation in affecting the balance of alternate reproductive modes and the contextual nature of asexual reproduction in rare species. PMID:25873148

  8. Cattail invasion of sedge/grass meadows in Lake Ontario: Photointerpretation analysis of sixteen wetlands over five decades

    USGS Publications Warehouse

    Wilcox, D.A.; Kowalski, K.P.; Hoare, H.L.; Carlson, M.L.; Morgan, H.N.

    2008-01-01

    Photointerpretation studies were conducted to evaluate vegetation changes in wetlands of Lake Ontario and the upper St. Lawrence River associated with regulation of water levels since about 1960. The studies used photographs from 16 sites (four each from drowned river mouth, barrier beach, open embayment, and protected embayment wetlands) and spanned a period from the 1950s to 2001 at roughly decadal intervals. Meadow marsh was the most prominent vegetation type in most wetlands in the late 1950s when water levels had declined following high lake levels in the early 1950s. Meadow marsh increased at some sites in the mid-1960s in response to low lake levels and decreased at all sites in the late 1970s following a period of high lake levels. Typha increased at nearly all sites, except wave-exposed open embayments, in the 1970s. Meadow marsh continued to decrease and Typha to increase at most sites during sustained higher lake levels through the 1980s, 1990s, and into 2001. Most vegetation changes could be correlated with lake-level changes and with life-history strategies and physiological tolerances to water depth of prominent taxa. Analyses of GIS coverages demonstrated that much of the Typha invasion was landward into meadow marsh, largely by Typha x glauca. Lesser expansion toward open water included both T. x glauca and T. angustifolia. Although many models focus on the seed bank as a key component of vegetative change in wetlands, our results suggest that canopy-dominating, moisture-requiring Typha was able to invade meadow marsh at higher elevations because sustained higher lake levels allowed it to survive and overtake sedges and grasses that can tolerate periods of drier soil conditions.

  9. Contrasting patterns of clonality and fine-scale genetic structure in two rare sedges with differing geographic distributions.

    PubMed

    Binks, R M; Millar, M A; Byrne, M

    2015-09-01

    For plants with mixed reproductive capabilities, asexual reproduction is more frequent in rare species and is considered a strategy for persistence when sexual recruitment is limited. We investigate whether asexual reproduction contributes to the persistence of two co-occurring, rare sedges that both experience irregular seed set and if their differing geographic distributions have a role in the relative contribution of clonality. Genotypic richness was high (R=0.889±0.02) across the clustered populations of Lepidosperma sp. Mt Caudan and, where detected, clonal patches were small, both in ramet numbers (⩽3 ramets/genet) and physical size (1.3±0.1 m). In contrast, genotypic richness was lower in the isolated L. sp. Parker Range populations, albeit more variable (R=0.437±0.13), with genets as large as 17 ramets and up to 5.8 m in size. Aggregated clonal growth generated significant fine-scale genetic structure in both species but to a greater spatial extent and with additional genet-level structure in L. sp. Parker Range that is likely due to restricted seed dispersal. Despite both species being rare, asexual reproduction clearly has a more important role in the persistence of L. sp. Parker Range than L. sp. Mt Caudan. This is consistent with our prediction that limitations to sexual reproduction, via geographic isolation to effective gene exchange, can lead to greater contributions of asexual reproduction. These results demonstrate the role of population isolation in affecting the balance of alternate reproductive modes and the contextual nature of asexual reproduction in rare species.

  10. Wetting and spreading

    NASA Astrophysics Data System (ADS)

    Bonn, Daniel; Eggers, Jens; Indekeu, Joseph; Meunier, Jacques; Rolley, Etienne

    2009-04-01

    Wetting phenomena are ubiquitous in nature and technology. A solid substrate exposed to the environment is almost invariably covered by a layer of fluid material. In this review, the surface forces that lead to wetting are considered, and the equilibrium surface coverage of a substrate in contact with a drop of liquid. Depending on the nature of the surface forces involved, different scenarios for wetting phase transitions are possible; recent progress allows us to relate the critical exponents directly to the nature of the surface forces which lead to the different wetting scenarios. Thermal fluctuation effects, which can be greatly enhanced for wetting of geometrically or chemically structured substrates, and are much stronger in colloidal suspensions, modify the adsorption singularities. Macroscopic descriptions and microscopic theories have been developed to understand and predict wetting behavior relevant to microfluidics and nanofluidics applications. Then the dynamics of wetting is examined. A drop, placed on a substrate which it wets, spreads out to form a film. Conversely, a nonwetted substrate previously covered by a film dewets upon an appropriate change of system parameters. The hydrodynamics of both wetting and dewetting is influenced by the presence of the three-phase contact line separating “wet” regions from those that are either dry or covered by a microscopic film only. Recent theoretical, experimental, and numerical progress in the description of moving contact line dynamics are reviewed, and its relation to the thermodynamics of wetting is explored. In addition, recent progress on rough surfaces is surveyed. The anchoring of contact lines and contact angle hysteresis are explored resulting from surface inhomogeneities. Further, new ways to mold wetting characteristics according to technological constraints are discussed, for example, the use of patterned surfaces, surfactants, or complex fluids.

  11. Relationship between Trophic Status and Methanogenic Pathways in Alaskan Peatlands

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Liu, X.; Sidelinger, W.; Wang, Y.; Hines, M. E.; Langford, L.; Chanton, J.

    2015-12-01

    To improve predictions of naturally emitted CH4 from northern wetlands, it is necessary to further examine the methanogenic pathways in these wetlands. Stable isotope C ratios (δ13C) have been used as a robust tool to distinguish different pathways, but different sources of parent compounds (acetate and CO2) with unique δ13C may add complexity to previously established criteria. Large portions of peatlands accommodate a mixture of different sphagna and sedges. Plant species may look very similar and belong to the same genus but are different morphologically and physiologically. To better understand the relationships between surface vegetation patterns and methanogenic pathways, 26 peatland sites were studied in Fairbanks and Anchorage, Alaska in summers of 2014 and 2015. These sites were ordinated using multiple factor analysis into 3 clusters based on pH, temp, CH4 and volatile fatty acids production rates, δ13C values, and surface vegetation species/pattern. In the low-pH trophic cluster (pH~3.5), non-vascular/vascular plant ratios (NV/V) were ~ 0.87 and dominated by diverse Sphagnum species and specific sedges (Eriophorum vaginatum), and fermentation was the dominant end-point in decomposition with no CH4 detected. Although NV/V is about the same in the intermediate cluster (0.74) (pH~4.5), and Sphagnum squarrosum was largely present, both hydrogenotrophic (HM) and acetoclastic methanogenesis (AM) were very active. Syntrophy was present at certain sites, which may provide CO2 with unique δ13C for CH4 production. At the highest pH trophic cluster examined in this study (pH~5), non-vascular plants were almost not existent and Carex aquatilis dominated. CH4 production rates (mainly HM) were slower than those in the intermediate cluster and the apparent fractionation factor a was lower than in the sites with syntrophy, which warrants further investigation of the position and compound specific δ13C analysis of volatile fatty acids.

  12. Chamber and Diffusive Based Carbon Flux Measurements in an Alaskan Arctic Ecosystem

    NASA Astrophysics Data System (ADS)

    Wilkman, E.; Oechel, W. C.; Zona, D.

    2013-12-01

    Eric Wilkman, Walter Oechel, Donatella Zona Comprising an area of more than 7 x 106 km2 and containing over 11% of the world's organic matter pool, Arctic terrestrial ecosystems are vitally important components of the global carbon cycle, yet their structure and functioning are sensitive to subtle changes in climate and many of these functional changes can have large effects on the atmosphere and future climate regimes (Callaghan & Maxwell 1995, Chapin et al. 2002). Historically these northern ecosystems have acted as strong C sinks, sequestering large stores of atmospheric C due to photosynthetic dominance in the short summer season and low rates of decomposition throughout the rest of the year as a consequence of cold, nutrient poor, and generally water-logged conditions. Currently, much of this previously stored carbon is at risk of loss to the atmosphere due to accelerated soil organic matter decomposition in warmer future climates (Grogan & Chapin 2000). Although there have been numerous studies on Arctic carbon dynamics, much of the previous soil flux work has been done at limited time intervals, due to both the harshness of the environment and labor and time constraints. Therefore, in June of 2013 an Ultraportable Greenhouse Gas Analyzer (UGGA - Los Gatos Research Inc.) was deployed in concert with the LI-8100A Automated Soil Flux System (LI-COR Biosciences) in Barrow, AK to gather high temporal frequency soil CO2 and CH4 fluxes from a wet sedge tundra ecosystem. An additional UGGA in combination with diffusive probes, installed in the same location, provides year-round soil and snow CO2 and CH4 concentrations. When used in combination with the recently purchased AlphaGUARD portable radon monitor (Saphymo GmbH), continuous soil and snow diffusivities and fluxes of CO2 and CH4 can be calculated (Lehmann & Lehmann 2000). Of particular note, measuring soil gas concentration over a diffusive gradient in this way allows one to separate both net production and

  13. Very, Very Fast Wetting

    NASA Technical Reports Server (NTRS)

    Jacqmin, David; Lee, Chi-Ming (Technical Monitor); Salzman, Jack (Technical Monitor)

    2001-01-01

    Just after formation, optical fibers are wetted stably with acrylate at capillary numbers routinely exceeding 1000. It is hypothesized that this is possible because of dissolution of air into the liquid coating. A lubrication/boundary integral analysis that includes gas diffusion and solubility is developed. It is applied using conservatively estimated solubility and diffusivity coefficients and solutions are found that are consistent with industry practice and with the hypothesis. The results also agree with the claim of Deneka, Kar & Mensah (1988) that the use of high solubility gases to bathe a wetting line allows significantly greater wetting speeds. The solutions indicate a maximum speed of wetting which increases with gas solubility and with reduction in wetting-channel diameter.

  14. Applications of remote sensing data to the Alaskan environment

    NASA Technical Reports Server (NTRS)

    Belon, A. E.; Iller, J. M.

    1973-01-01

    The ERTS program provides a means to overcome the formidable logistic and economic costs of preparing environmental surveys of the vast and relatively unexplored regions of Alaska. There is an excellent potential in satellite remote sensing to benefit Federal, state, local, and private agencies, by providing a new synoptic data base which is necessary for the preparation of the needed surveys and the search for solutions to environmental management problems. One approach in coupling satellite data to Alaskan problems is a major program initiated by the University of Alaska and funded by NASA's Goddard Space Flight Center. This included 12 projects whose aims were to study the feasibility of applying ERTS data to the disciplines of ecology, agriculture, hydrology, wildlife management, oceanography, geology, glaciology, volcanology, and archaeology.

  15. Development of Alaskan gas hydrate resources. Final report

    SciTech Connect

    Kamath, V.A.; Sharma, G.D.; Patil, S.L.

    1991-06-01

    The research undertaken in this project pertains to study of various techniques for production of natural gas from Alaskan gas hydrates such as, depressurization, injection of hot water, steam, brine, methanol and ethylene glycol solutions through experimental investigation of decomposition characteristics of hydrate cores. An experimental study has been conducted to measure the effective gas permeability changes as hydrates form in the sandpack and the results have been used to determine the reduction in the effective gas permeability of the sandpack as a function of hydrate saturation. A user friendly, interactive, menu-driven, numerical difference simulator has been developed to model the dissociation of natural gas hydrates in porous media with variable thermal properties. A numerical, finite element simulator has been developed to model the dissociation of hydrates during hot water injection process.

  16. Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities

    SciTech Connect

    Duncan, Kathleen E.; Gieg, Lisa M.; Parisi, Victoria A.; Tanner, Ralph S.; Green Tringe, Susannah; Bristow, Jim; Suflita, Joseph M.

    2009-09-16

    Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon, with standard treatment methods targeting mesophilic sulfatereducing bacteria. In assessing biocorrosion potential at an Alaskan North Slope oil field, we identified thermophilic hydrogen-using methanogens, syntrophic bacteria, peptideand amino acid-fermenting bacteria, iron reducers, sulfur/thiosulfate-reducing bacteria and sulfate-reducing archaea. These microbes can stimulate metal corrosion through production of organic acids, CO2, sulfur species, and via hydrogen oxidation and iron reduction, implicating many more types of organisms than are currently targeted. Micromolar quantities of putative anaerobic metabolites of C1-C4 n-alkanes in pipeline fluids were detected, implying that these low molecular weight hydrocarbons, routinely injected into reservoirs for oil recovery purposes, are biodegraded and provide biocorrosive microbial communities with an important source of nutrients.

  17. Air-cushion tankers for Alaskan North Slope oil

    NASA Technical Reports Server (NTRS)

    Anderson, J. L.

    1973-01-01

    A concept is described for transporting oil from the Arctic to southern markets in 10,000-ton, chemically fueled air-cushion vehicles (ACV's) configured as tankers. Based on preliminary cost estimates the conceptual ACV tanker system as tailored to the transportation of Alaskan North Slope oil could deliver the oil for about the same price per barrel as the proposed trans-Alaska pipeline with only one-third of the capital investment. The report includes the description of the conceptual system and its operation; preliminary cost estimates; an appraisal of ACV tanker development; and a comparison of system costs, versatility, vulnerability, and ecological effect with those of the trans-Alaska pipeline.

  18. Kinetics of Reactive Wetting

    SciTech Connect

    YOST, FREDERICK G.

    1999-09-09

    The importance of interfacial processes in materials joining has a long history. A significant amount of work has suggested that processes collateral to wetting can affect the extent of wetting and moderate or retard wetting rate. Even very small additions of a constituent, known to react with the substrate, cause pronounced improvement in wetting and are exploited in braze alloys, especially those used for joining to ceramics. The wide diversity of processes, such as diffusion, chemical reaction, and fluxing, and their possible combinations suggest that various rate laws should be expected for wetting kinetics depending on the controlling processes. These rate laws are expected to differ crucially from the standard fluid controlled wetting models found in the literature. Voitovitch et al. and Mortensen et al. have shown data that suggests diffusion control for some systems and reaction control for others. They also presented a model of wetting kinetics controlled by the diffusion of a constituent contained by the wetting fluid. In the following a model will be constructed for the wetting kinetics of a small droplet of metal containing a constituent that diffuses to the wetting line and chemically reacts with a flat, smooth substrate. The model is similar to that of Voitovitch et al. and Mortensen et al. but incorporates chemical reaction kinetics such that the result contains both diffusion and reaction kinetics. The model is constructed in the circular cylinder coordinate system, satisfies the diffusion equation under conditions of slow flow, and considers diffusion and reaction at the wetting line to be processes in series. This is done by solving the diffusion equation with proper initial and boundary conditions, computing the diffusive flux at the wetting line and equating this to both the convective flux and reaction flux. This procedure is similar to equating the current flowing in components of a series circuit. The wetting rate will be computed versus time

  19. Aerobic Methane Oxidation in Alaskan Lakes Along a Latitudinal Transect

    NASA Astrophysics Data System (ADS)

    Martinez-Cruz, K. C.; Sepulveda-Jauregui, A.; Walter Anthony, K. M.; Anthony, P.; Thalasso, F.

    2013-12-01

    Karla Martinez-Cruz* **, Armando Sepulveda-Jauregui*, Katey M. Walter Anthony*, Peter Anthony*, and Frederic Thalasso**. * Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, Alaska. ** Biotechnology and Bioengineering Department, Cinvestav, Mexico city, D. F., Mexico. Methane (CH4) is the third most important greenhouse gas in the atmosphere, after carbon dioxide and water vapor. Boreal lakes play an important role in the current global warming by contributing as much as 6% of global atmospheric CH4 sources annually. On the other hand, aerobic methane oxidation (methanotrophy) in lake water is a fundamental process in global methane cycling that reduces the amount of CH4 emissions to the atmosphere. Several environmental factors affect aerobic methane oxidation in the water column both directly and indirectly, including concentration of CH4 and O2, temperature and carbon budgets of lakes. We analyzed the potential of aerobic methane oxidation (PMO) rates in incubations of water collected from 30 Alaskan lakes along a north-south transect during winter and summer 2011. Our findings showed an effect of CH4 and O2 concentrations, temperature and yedoma thawing permafrost on PMO activity in the lake water. The highest PMO rates were observed in summer by lakes situated on thawing yedoma permafrost, most of them located in the interior of Alaska. We also estimated that 60-80% of all CH4 produced in Alaskan lakes could be taken up by methanotrophs in the lake water column, showing the significant influence of aerobic methane oxidation of boreal lakes to the global CH4 budget.

  20. Kinetics of reactive wetting

    SciTech Connect

    Yost, F.G.

    2000-04-14

    The importance of interfacial processes in materials joining has a long history. A significant amount of work has suggested that processes collateral to wetting can affect the extent of wetting and moderate or retard wetting rate. Even very small additions of a constituent, known to react with the substrate, cause pronounced improvement in wetting and are exploited in braze alloys, especially those used for joining to ceramics. In the following a model will be constructed for the wetting kinetics of a small droplet of metal containing a constituent that diffuses to the wetting line and chemically reacts with a flat, smooth substrate. The model is similar to that of Voitovitch et al. and Mortensen et al. but incorporates chemical reaction kinetics such that the result contains both diffusion and reaction kinetics. The model is constructed in the circular cylinder coordinate system, satisfies the diffusion equation under conditions of slow flow, and considers diffusion and reaction at the wetting line to be processes in series. This is done by solving the diffusion equation with proper initial and boundary conditions, computing the diffusive flux at the wetting line, and equating this to both the convective flux and reaction flux. This procedure is similar to equating the current flowing in components of a series circuit. The wetting rate will be computed versus time for a variety of diffusion and reaction conditions. A transition is observed from nonlinear (diffusive) to linear (reactive) behavior as the control parameters (such as the diffusion coefficient) are modified. This is in agreement with experimental observations. The adequacy of the slow flow condition, used in this type of analysis, is discussed and an amended procedure is suggested.

  1. Breeding bird territory placement in riparian wet meadows in relation to invasive reed canary grass, Phalaris arundinacea

    USGS Publications Warehouse

    Kirsch, E.M.; Gray, B.R.; Fox, T.J.; Thogmartin, W.E.

    2007-01-01

    Invasive plants are a growing concern worldwide for conservation of native habitats. In endangered wet meadow habitat in the Upper Midwestern United States, reed canary grass (Phalaris arundinacea) is a recognized problem and its prevalence is more widespread than the better-known invasive wetland plant purple loosestrife (Lythrum salicaria). Although resource managers are concerned about the effect of reed canary grass on birds, this is the first study to report how common wet meadow birds use habitat in relation to reed canary grass cover and dominance. We examined three response variables: territory placement, size of territories, and numbers of territories per plot in relation to cover of reed canary grass. Territory locations for Sedge Wren (Cistothorus platensis) and Song Sparrow (Melospiza melodia) were positively associated with reed canary grass cover, while those for Common Yellowthroat (Geothlypis trichas) were not. Only Swamp Sparrow (M. georgiana) territory locations were negatively associated with reed canary grass cover and dominance (which indicated a tendency to place territories where there was no reed canary grass or where many plant species occurred with reed canary grass). Swamp Sparrow territories were positively associated with vegetation height density and litter depth. Common Yellowthroat territories were positively associated with vegetation height density and shrub cover. Song Sparrow territories were negatively associated with litter depth. Reed canary grass cover within territories was not associated with territory size for any of these four bird species. Territory density per plot was not associated with average reed canary grass cover of plots for all four species. Sedge Wrens and Song Sparrows may not respond negatively to reed canary grass because this grass is native to wet meadows of North America, and in the study area it merely replaces other tall lush plants. Avoidance of reed canary grass by Swamp Sparrows may be mediated

  2. Wetting Transition in Water

    NASA Astrophysics Data System (ADS)

    Friedman, S. R.; Khalil, M.; Taborek, P.

    2013-11-01

    Optical images were used to study the wetting behavior of water on graphite, sapphire, and quartz along the liquid vapor coexistence curve from room temperature to 300°C. Wetting transitions were identified by the temperature at which the contact angle decreased to zero and also by the disappearance of dropwise condensation. These two methods yielded consistent values for the wetting temperatures, which were 185°C, 234°C, and 271°C for water on quartz, sapphire, and graphite, respectively. We compare our results with the theoretical predictions based on a simplified model of the water-substrate potential and sharp interfaces.

  3. Wetting transition in water.

    PubMed

    Friedman, S R; Khalil, M; Taborek, P

    2013-11-27

    Optical images were used to study the wetting behavior of water on graphite, sapphire, and quartz along the liquid vapor coexistence curve from room temperature to 300 °C. Wetting transitions were identified by the temperature at which the contact angle decreased to zero and also by the disappearance of dropwise condensation. These two methods yielded consistent values for the wetting temperatures, which were 185 °C, 234 °C, and 271 °C for water on quartz, sapphire, and graphite, respectively. We compare our results with the theoretical predictions based on a simplified model of the water-substrate potential and sharp interfaces.

  4. WET SOLIDS FLOW ENHANCEMENT

    SciTech Connect

    Hugo S. Caram; Natalie Foster

    1999-07-01

    The strain-stress behavior of a wet granular media was measured using a split Parfitt tensile tester. In all cases the stress increases linearly with distance until the maximum uniaxial tensile stress is reached. The stress then decreases exponentially with distance after this maximum is reached. The linear region indicates that wet solids behave elastically for stresses below the tensile stresses and can store significant elastic energy. The elastic deformation cannot be explained by analyzing the behavior of individual capillary bridges and requires accounting for the deformation of the solids particles. The elastic modulus of the wet granular material remains unexplained.

  5. WET SOLIDS FLOW ENHANCEMENT

    SciTech Connect

    Hugo S. Caram; Natalie Foster

    1998-03-30

    The strain-stress behavior of a wet granular media was measured using a split Parfitt tensile tester. In all cases the stress increases linearly with distance until the maximum uniaxial tensile stress is reached. The stress then decreases exponentially with distance after this maximum is reached. The linear region indicates that wet solids behave elastically for stresses below the tensile stresses and can store significant elastic energy. The elastic deformation cannot be explained by analyzing the behavior of individual capillary bridges and may require accounting for the deformation of the solids particles. The elastic modulus of the wet granular material remains unexplained.

  6. Spatial and Temporal Variation in Primary Productivity (NDVI) of Coastal Alaskan Tundra: Decreased Vegetation Growth Following Earlier Snowmelt

    NASA Technical Reports Server (NTRS)

    Gamon, John A.; Huemmrich, K. Fred; Stone, Robert S.; Tweedie, Craig E.

    2015-01-01

    In the Arctic, earlier snowmelt and longer growing seasons due to warming have been hypothesized to increase vegetation productivity. Using the Normalized Difference Vegetation Index (NDVI) from both field and satellite measurements as an indicator of vegetation phenology and productivity, we monitored spatial and temporal patterns of vegetation growth for a coastal wet sedge tundra site near Barrow, Alaska over three growing seasons (2000-2002). Contrary to expectation, earlier snowmelt did not lead to increased productivity. Instead, productivity was associated primarily with precipitation and soil moisture, and secondarily with growing degree days, which, during this period, led to reduced growth in years with earlier snowmelt. Additional moisture effects on productivity and species distribution, operating over a longer time scale, were evident in spatial NDVI patterns associated with microtopography. Lower, wetter regions dominated by graminoids were more productive than higher, drier locations having a higher percentage of lichens and mosses, despite the earlier snowmelt at the more elevated sites. These results call into question the oft-stated hypothesis that earlier arctic growing seasons will lead to greater vegetation productivity. Rather, they agree with an emerging body of evidence from recent field studies indicating that early-season, local environmental conditions, notably moisture and temperature, are primary factors determining arctic vegetation productivity. For this coastal arctic site, early growing season conditions are strongly influenced by microtopography, hydrology, and regional sea ice dynamics, and may not be easily predicted from snowmelt date or seasonal average air temperatures alone. Our comparison of field to satellite NDVI also highlights the value of in-situ monitoring of actual vegetation responses using field optical sampling to obtain detailed information on surface conditions not possible from satellite observations alone.

  7. Modelling guided waves in the Alaskan-Aleutian subduction zone

    NASA Astrophysics Data System (ADS)

    Coulson, Sophie; Garth, Thomas; Reitbrock, Andreas

    2016-04-01

    Subduction zone guided wave arrivals from intermediate depth earthquakes (70-300 km depth) have a huge potential to tell us about the velocity structure of the subducting oceanic crust as it dehydrates at these depths. We see guided waves as the oceanic crust has a slower seismic velocity than the surrounding material, and so high frequency energy is retained and delayed in the crustal material. Lower frequency energy is not retained in this crustal waveguide and so travels at faster velocities of the surrounding material. This gives a unique observation at the surface with low frequency energy arriving before the higher frequencies. We constrain this guided wave dispersion by comparing the waveforms recorded in real subduction zones with simulated waveforms, produced using finite difference full waveform modelling techniques. This method has been used to show that hydrated minerals in the oceanic crust persist to much greater depths than accepted thermal petrological subduction zone models would suggest in Northern Japan (Garth & Rietbrock, 2014a), and South America (Garth & Rietbrock, in prep). These observations also suggest that the subducting oceanic mantle may be highly hydrated at intermediate depth by dipping normal faults (Garth & Rietbrock 2014b). We use this guided wave analysis technique to constrain the velocity structure of the down going ~45 Ma Pacific plate beneath Alaska. Dispersion analysis is primarily carried out on guided wave arrivals recorded on the Alaskan regional seismic network. Earthquake locations from global earthquake catalogues (ISC and PDE) and regional earthquake locations from the AEIC (Alaskan Earthquake Information Centre) catalogue are used to constrain the slab geometry and to identify potentially dispersive events. Dispersed arrivals are seen at stations close to the trench, with high frequency (>2 Hz) arrivals delayed by 2 - 4 seconds. This dispersion is analysed to constrain the velocity and width of the proposed waveguide

  8. Wrinkling of wet paper

    NASA Astrophysics Data System (ADS)

    Kim, Ho-Young; Kim, Jungchul; Mahadevan, L.

    2011-11-01

    It is a mundane experience that paper stained with water wrinkles. It is because a wetted portion of paper, which swells due to the hygroexpansive nature of the cellulose fiber network, deforms out of its original plane. Here we quantify the dynamics of wrinkling of wet paper coupled to the capillary imbibition of water into paper using a combination of experiment and theory. While supplying water from a capillary tube that touches the center of a paper strip, we measure the spreading rate of the wet area, wait time for the out-of-plane buckling, and temporal growth of a wrinkling magnitude. Using a theoretical model assuming a linear increase of the strain and an exponential decay of the elastic modulus with the water concentration, we construct scaling laws to predict the simultaneous capillary imbibition and wrinkling rates. This work was supported by the Wyss Institute of Harvard University.

  9. Water storage capacity of the natural river valley - how sedge communities influence it. Case study of Upper Biebrza Basin (Poland) based on ALS and TLS data

    NASA Astrophysics Data System (ADS)

    Brach, Marcin; Chormański, Jarosław

    2014-05-01

    The exact determination of water storage capacity in river valley is an important issue for hydrologists, ecologist and flood modellers. In case of natural river valley, the dense and complexity vegetation of the natural ecosystems can influence the proper identification of the water storage. Methods considered to be sufficient in other cases (urbanized, agricultural) may not produce correct results. Sedge communities in natural river valleys form characteristic tussocks, built from the species roots, other organic material and silt or mud. They are formed due to partial flooding during the inundation, so the plants can survive in hard, anaerobic conditions. They can growth even up to 0.5 meters, which is not so visible due to very dense vegetation in the valleys. These tussocks form a microtopography or a river valley. Currently, the most commonly used technology to register the terrain topography is an Airborne Laser Scanning (ALS), but in the case of the tussocks and the dense vegetation it generates high errors on elevation in the areas of the sedges (Carex appropinquata). This study concerns the Upper Biebrza Valley which is located in the northeastern Poland. For purpose of our work we used Terrestrial Laser Scanner (TLS) technology to determine microtopography of selected fields. Before measurements, the green part of the sedge was cut in selected measurements fields. It make possible to register only tussocks shape. Next, step was collection of the airborne ALS data of the valley with density of 8 points/sq m. The experimental field was divided on two sub-fields: one was cut and scanned using TLS before ALS collection, while the second after. Data collected as ALS and the TLS were then compared. The accuracy of the ALS data depends on the land cover of an area, while TLS accuracy is around 2 millimeters (when georeferenced it depends on the accuracy of reference points - in our case it was made using GPS RTK which gave us accuracy of few centimeters). The

  10. Rapid body size decline in Alaskan Pleistocene horses before extinction.

    PubMed

    Guthrie, R Dale

    2003-11-13

    About 70% of North American large mammal species were lost at the end of the Pleistocene epoch. The causes of this extinction--the role of humans versus that of climate--have been the focus of much controversy. Horses have figured centrally in that debate, because equid species dominated North American late Pleistocene faunas in terms of abundance, geographical distribution, and species variety, yet none survived into the Holocene epoch. The timing of these equid regional extinctions and accompanying evolutionary changes are poorly known. In an attempt to document better the decline and demise of two Alaskan Pleistocene equids, I selected a large number of fossils from the latest Pleistocene for radiocarbon dating. Here I show that horses underwent a rapid decline in body size before extinction, and I propose that the size decline and subsequent regional extinction at 12,500 radiocarbon years before present are best attributed to a coincident climatic/vegetational shift. The present data do not support human overkill and several other proposed extinction causes, and also show that large mammal species responded somewhat individualistically to climate changes at the end of the Pleistocene.

  11. Ice loss and sea level rise contribution from Alaskan glaciers

    NASA Astrophysics Data System (ADS)

    Berthier, E.; Schiefer, E.; Clarke, G. K.; Menounos, B.; Rémy, F.; Cazenave, A. A.

    2009-12-01

    Over the last 50 years, retreating glaciers and ice caps (GIC) contributed 0.5 mm/yr to SLR, and one third is believed to originate from ice masses bordering the Gulf of Alaska. However, these estimates of ice wastage in Alaska are based on methods that directly measure mass changes from a limited number of glaciers and extrapolate the results to estimate ice loss for the many thousands of others. Here, using a new glacier inventory with elevation changes derived from sequential digital elevation models (DEMs), we found that, between 1962 and 2006, Alaskan glaciers lost 41.9 ± 8.6 km**3/yr water equivalent (w.e.) and contributed 0.12 ± 0.02 mm/yr to SLR. Our ice loss is 34% lower than previous estimates. Reasons for our lower values include the higher spatial resolution of the glacier inventory used in our study and the complex pattern of ice elevation changes at the scale of individual glaciers and mountain ranges which was not resolved in earlier work. Our ice elevation changes reveal that glacier dynamics (surges, phase of the tidewater cycle, etc...) have a profound effect on the wastage of Alaska glaciers. 3D satellite view of Columbia glacier, Chugach Mountains, Alaska. (Copyright CNES 2007, Distribution Spot Image, processing E. Berthier CNRS)

  12. Quantifying seismic survey reverberation off the Alaskan North Slope.

    PubMed

    Guerra, Melania; Thode, Aaron M; Blackwell, Susanna B; Michael Macrander, A

    2011-11-01

    Shallow-water airgun survey activities off the North Slope of Alaska generate impulsive sounds that are the focus of much regulatory attention. Reverberation from repetitive airgun shots, however, can also increase background noise levels, which can decrease the detection range of nearby passive acoustic monitoring (PAM) systems. Typical acoustic metrics for impulsive signals provide no quantitative information about reverberation or its relative effect on the ambient acoustic environment. Here, two conservative metrics are defined for quantifying reverberation: a minimum level metric measures reverberation levels that exist between airgun pulse arrivals, while a reverberation metric estimates the relative magnitude of reverberation vs expected ambient levels in the hypothetical absence of airgun activity, using satellite-measured wind data. The metrics are applied to acoustic data measured by autonomous recorders in the Alaskan Beaufort Sea in 2008 and demonstrate how seismic surveys can increase the background noise over natural ambient levels by 30-45 dB within 1 km of the activity, by 10-25 dB within 15 km of the activity, and by a few dB at 128 km range. These results suggest that shallow-water reverberation would reduce the performance of nearby PAM systems when monitoring for marine mammals within a few kilometers of shallow-water seismic surveys.

  13. ERTS imagery applied to Alaskan coastal problems. [surface water circulation

    NASA Technical Reports Server (NTRS)

    Wright, F. F.; Sharma, G. D.; Burbank, D. C.; Burns, J. J.

    1974-01-01

    Along the Alaska coast, surface water circulation is relatively easy to study with ERTS imagery. Highly turbid river water, sea ice, and fluvial ice have proven to be excellent tracers of the surface waters. Sea truth studies in the Gulf of Alaska, Cook Inlet, Bristol Bay, and the Bering Strait area have established the reliability of these tracers. ERTS imagery in the MSS 4 and 5 bands is particularly useful for observing lower concentrations of suspended sediment, while MSS 6 data is best for the most concentrated plumes. Ice features are most clearly seen on MSS 7 imagery; fracture patterns and the movement of specific floes can be used to map circulation in the winter when runoff is restricted, if appropriate allowance is made for wind influence. Current patterns interpreted from satellite data are only two-dimensional, but since most biological activity and pollution are concentrated near the surface, the information developed can be of direct utility. Details of Alaska inshore circulation of importance to coastal engineering, navigation, pollution studies, and fisheries development have been clarified with satellite data. ERTS has made possible the analysis of circulation in many parts of the Alaskan coast.

  14. Soluble trace elements and total mercury in Arctic Alaskan snow

    USGS Publications Warehouse

    Snyder-Conn, E.; Garbarino, J.R.; Hoffman, G.L.; Oelkers, A.

    1997-01-01

    Ultraclean field and laboratory procedures were used to examine trace element concentrations in northern Alaskan snow. Sixteen soluble trace elements and total mercury were determined in snow core samples representing the annual snowfall deposited during the 1993-94 season at two sites in the Prudhoe Bay oil field and nine sites in the Arctic National Wildlife Refuge (Arctic NWR). Results indicate there were two distinct point sources for trace elements in the Prudhoe Bay oil field - a source associated with oil and gas production and a source associated with municipal solid-waste incineration. Soluble trace element concentrations measured in snow from the Arctic NWR resembled concentrations of trace elements measured elsewhere in the Arctic using clean sample-collection and processing techniques and were consistent with deposition resulting from widespread arctic atmospheric contamination. With the exception of elements associated with sea salts, there were no orographic or east-west trends observed in the Arctic NWR data, nor were there any detectable influences from the Prudhoe Bay oil field, probably because of the predominant easterly and northeasterly winds on the North Slope of Alaska. However, regression analysis on latitude suggested significant south-to-north increases in selected trace element concentrations, many of which appear unrelated to the sea salt contribution.

  15. Ecology of invasive Melilotus albus on Alaskan glacial river floodplains

    USGS Publications Warehouse

    Conn, Jeff S.; Werdin-Pfisterer, Nancy R.; Beattie, Katherine L.; Densmore, Roseann V.

    2011-01-01

    Melilotus albus (white sweetclover) has invaded Alaskan glacial river floodplains. We measured cover and density of plant species and environmental variables along transects perpendicular to the Nenana, Matanuska, and Stikine Rivers to study interactions between M. albus and other plant species and to characterize the environment where it establishes. Melilotus albus was a pioneer species on recently disturbed sites and did not persist into closed canopy forests. The relationships between M. albus cover and density and other species were site-specific.Melilotus albus was negatively correlated with native species Elaeagnus commutata at the Nenana River, but not at the Matanuska River. Melilotus albus was positively correlated with the exotic species Crepis tectorumand Taraxacum officinale at the Matanuska River and T. officinale on the upper Stikine River. However, the high density of M. albus at a lower Stikine River site was negatively correlated with T. officinale and several native species including Lathyrus japonicus var. maritimus and Salix alaxensis. Glacial river floodplains in Alaska are highly disturbed and are corridors for exotic plant species movement. Melilotus albus at moderate to low densities may facilitate establishment of exotic species, but at high densities can reduce the cover and density of both exotic and native species.

  16. A Formal Messaging Notation for Alaskan Aviation Data

    NASA Technical Reports Server (NTRS)

    Rios, Joseph L.

    2015-01-01

    Data exchange is an increasingly important aspect of the National Airspace System. While many data communication channels have become more capable of sending and receiving data at higher throughput rates, there is still a need to use communication channels efficiently with limited throughput. The limitation can be based on technological issues, financial considerations, or both. This paper provides a complete description of several important aviation weather data in Abstract Syntax Notation format. By doing so, data providers can take advantage of Abstract Syntax Notation's ability to encode data in a highly compressed format. When data such as pilot weather reports, surface weather observations, and various weather predictions are compressed in such a manner, it allows for the efficient use of throughput-limited communication channels. This paper provides details on the Abstract Syntax Notation One (ASN.1) implementation for Alaskan aviation data, and demonstrates its use on real-world aviation weather data samples as Alaska has sparse terrestrial data infrastructure and data are often sent via relatively costly satellite channels.

  17. Quantifying seismic survey reverberation off the Alaskan North Slope.

    PubMed

    Guerra, Melania; Thode, Aaron M; Blackwell, Susanna B; Michael Macrander, A

    2011-11-01

    Shallow-water airgun survey activities off the North Slope of Alaska generate impulsive sounds that are the focus of much regulatory attention. Reverberation from repetitive airgun shots, however, can also increase background noise levels, which can decrease the detection range of nearby passive acoustic monitoring (PAM) systems. Typical acoustic metrics for impulsive signals provide no quantitative information about reverberation or its relative effect on the ambient acoustic environment. Here, two conservative metrics are defined for quantifying reverberation: a minimum level metric measures reverberation levels that exist between airgun pulse arrivals, while a reverberation metric estimates the relative magnitude of reverberation vs expected ambient levels in the hypothetical absence of airgun activity, using satellite-measured wind data. The metrics are applied to acoustic data measured by autonomous recorders in the Alaskan Beaufort Sea in 2008 and demonstrate how seismic surveys can increase the background noise over natural ambient levels by 30-45 dB within 1 km of the activity, by 10-25 dB within 15 km of the activity, and by a few dB at 128 km range. These results suggest that shallow-water reverberation would reduce the performance of nearby PAM systems when monitoring for marine mammals within a few kilometers of shallow-water seismic surveys. PMID:22087932

  18. 33 CFR 334.1290 - In Bering Sea, Shemya Island Area, Alaska; meteorological rocket launching facility, Alaskan Air...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., Alaska; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. 334.1290 Section...; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. (a) The danger zone. An arc of a...) Rockets will normally be launched one each day Monday through Friday between 9 a.m. and 3 p.m....

  19. 33 CFR 334.1290 - In Bering Sea, Shemya Island Area, Alaska; meteorological rocket launching facility, Alaskan Air...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Alaska; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. 334.1290 Section...; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. (a) The danger zone. An arc of a...) Rockets will normally be launched one each day Monday through Friday between 9 a.m. and 3 p.m....

  20. 33 CFR 334.1290 - In Bering Sea, Shemya Island Area, Alaska; meteorological rocket launching facility, Alaskan Air...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., Alaska; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. 334.1290 Section...; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. (a) The danger zone. An arc of a...) Rockets will normally be launched one each day Monday through Friday between 9 a.m. and 3 p.m....

  1. 33 CFR 334.1290 - In Bering Sea, Shemya Island Area, Alaska; meteorological rocket launching facility, Alaskan Air...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., Alaska; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. 334.1290 Section...; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. (a) The danger zone. An arc of a...) Rockets will normally be launched one each day Monday through Friday between 9 a.m. and 3 p.m....

  2. 33 CFR 334.1290 - In Bering Sea, Shemya Island Area, Alaska; meteorological rocket launching facility, Alaskan Air...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Alaska; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. 334.1290 Section...; meteorological rocket launching facility, Alaskan Air Command, U.S. Air Force. (a) The danger zone. An arc of a...) Rockets will normally be launched one each day Monday through Friday between 9 a.m. and 3 p.m....

  3. 25 CFR 243.6 - Which sales or transfers of Alaskan reindeer do not require a permit?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Which sales or transfers of Alaskan reindeer do not... AND WILDLIFE REINDEER IN ALASKA § 243.6 Which sales or transfers of Alaskan reindeer do not require a... reindeer or reindeer products; and (b) Sale of transfer of live reindeer between Alaska Natives or...

  4. 25 CFR 243.6 - Which sales or transfers of Alaskan reindeer do not require a permit?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Which sales or transfers of Alaskan reindeer do not... AND WILDLIFE REINDEER IN ALASKA § 243.6 Which sales or transfers of Alaskan reindeer do not require a... reindeer or reindeer products; and (b) Sale of transfer of live reindeer between Alaska Natives or...

  5. 25 CFR 243.6 - Which sales or transfers of Alaskan reindeer do not require a permit?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Which sales or transfers of Alaskan reindeer do not... AND WILDLIFE REINDEER IN ALASKA § 243.6 Which sales or transfers of Alaskan reindeer do not require a... reindeer or reindeer products; and (b) Sale of transfer of live reindeer between Alaska Natives or...

  6. 25 CFR 243.6 - Which sales or transfers of Alaskan reindeer do not require a permit?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Which sales or transfers of Alaskan reindeer do not... AND WILDLIFE REINDEER IN ALASKA § 243.6 Which sales or transfers of Alaskan reindeer do not require a... reindeer or reindeer products; and (b) Sale of transfer of live reindeer between Alaska Natives or...

  7. 25 CFR 243.6 - Which sales or transfers of Alaskan reindeer do not require a permit?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Which sales or transfers of Alaskan reindeer do not... AND WILDLIFE REINDEER IN ALASKA § 243.6 Which sales or transfers of Alaskan reindeer do not require a... reindeer or reindeer products; and (b) Sale of transfer of live reindeer between Alaska Natives or...

  8. Ventilation of North Pacific Intermediate Waters - The role of the Alaskan Gyre

    NASA Technical Reports Server (NTRS)

    Van Scoy, Kim A.; Olson, Donald B.; Fine, Rana A.

    1991-01-01

    Hydrographic data, tritium data, and potential vorticity calculations suggest that although North Pacific Intermediate Water is formed in the northwest, the Alaskan Gyre might be an additional ventilation site. The proposed ventilation is quantified by a vertical column tritium inventory, which indicates an excess of 0.08 kg of tritium in the Alaskan Gyre. An evaluation of the energy stored in the water column and of wind and buoyancy forcing shows that during winter conditions enough energy can be pumped into the system to force 26.80 sigma(theta) to outcrop in the Alaskan Gyre. Model results suggest that relatively limited outcrops in time and space (tens of days and several hundred kilometers in diameter) can account for the excess tritium.

  9. WET SOLIDS FLOW ENHANCEMENT

    SciTech Connect

    Hugo S. Caram; Natalie Foster

    1999-03-30

    The elastic modulus E of wet granular material was found to be of the order of 0.25 MPa, this value does not compare well with the value predicted for a cubic array of spheres under Hertzian contact were the predicted values were in the order of 250 MPa . The strain-stress behavior of a wet granular media was measured using a split Parfitt tensile tester. In all cases the stress increases linearly with distance until the maximum uniaxial tensile stress is reached. The stress then decreases exponentially with distance after this maximum is reached. The linear region indicates that wet solids behave elastically for stresses below the tensile stresses and can store significant elastic energy. The elastic deformation cannot be explained by analyzing the behavior of individual capillary bridges and requires accounting for the deformation of the solids particles. The elastic modulus of the wet granular material remains unexplained. New information was found to support the experimental finding and a first theory to explain the very small elastic modulus is presented. A new model based on the used of the finite element method is being developed.

  10. Wet and Wild Water.

    ERIC Educational Resources Information Center

    Indiana State Dept. of Education, Indianapolis. Center for School Improvement and Performance.

    This guide uses a thematic approach to show the integration of subjects (reading, mathematics, language arts, science/fine arts) and skills to create a context for learning. The contents of this guide are presented in a holistic format. There are six major topics in the guide, each with subtopics: (1) "Getting Your Feet Wet--An Introduction to…

  11. Characterizing Variation of Isotopic Markers in Northern Alaskan Caribou Forages

    NASA Astrophysics Data System (ADS)

    VanSomeren, L.; Barboza, P. S.; Gustine, D. D.; Parrett, L. S.; Stricker, C. A.

    2013-12-01

    Isotopic markers in feces and tissues are a potential tool for monitoring the importance of feeding areas for migratory herbivores such as caribou (Rangifer tarandus). Many of these techniques are currently limited by gaps in our knowledge of how these isotopic signatures vary over the landscape. We collected seven species of preferred caribou forages along a latitudinal gradient in the summer ranges of the Central Arctic (9 sites) and Teshekpuk Lake (4 sites) caribou herds during 2011 and 2012. We analyzed forages at peak protein content and at the end of the season to characterize temporal, species-specific, and spatial variation in isotopic markers. The availability of C and N was measured by digestion in vitro. Isotopic signatures of digested samples were used to calculate fractionation that would bias the isotopic signature of feces. The range of values for isotopes (all values ‰) of nitrogen (δ15N -9.5 - +4.3), and sulfur (δ34S -3.6 - +15.5) were greater than those for carbon (δ13C -30.5 - -24.9). Small declines in forage δ13C with latitude (Carex aquatilis, Eriophorum vaginatum, Salix pulchra, and S. richardsonii [all P < 0.01]), season (all species except C. bigelowii [all P ≤ 0.01]), and season x year (S. richardsonii; P = 0.01) were probably associated with changes in water availability. Fractionation of δ13C in early season forages was 0.1 × 1.0 and positively related to C availability (58% × 15%; P < 0.01) with the greatest fractionation for the highly digestible forb Pedicularis langsdorfii (1.43 × 0.44; P < 0.01). Sedges (Carex and Eriophorum) were significantly higher in δ15N than Salix spp. and other dicots (2.0 × 1.1 vs. -2.9 × 2.2; P < 0.01). For Salix spp., δ15N was consistent over the season and between years. Fractionation of δ15N in early season forages was 0.2 × 1.8 and not related to N availability (60% × 17%). For S. pulchra, δ34S may indicate usage of coastal habitats over foothills because δ34S was higher on the

  12. Alaskan malamute chondrodysplasia IV. Concentrations of zinc, copper and iron in various tissues.

    PubMed

    Brown, R G; Hoag, G N; Smart, M E; Boechner, G; Subden, R E

    1977-09-01

    Trace mineral concentrations in various tissues of the chondrodysplastic (dwarf) Alaskan Malamute are remarkably different as compared to normal. The zinc level in heart tissue was depressed in dwarf animals (26 weeks). Copper concentration in the liver is elevated two to four fold in 26 week old dwarf animals and iron levels are significantly elevated in kidney, liver and pancreas of these animals. These observations suggest that the dwarf Alaskan Malamutes suffer from a genetic defect in trace mineral metabolism. If this is the case, then many of the skeletal lesions reported for these animals may be attributed to disorders in either zinc or copper metabolism.

  13. PREFACE: Wetting: introductory note

    NASA Astrophysics Data System (ADS)

    Herminghaus, S.

    2005-03-01

    The discovery of wetting as a topic of physical science dates back two hundred years, to one of the many achievements of the eminent British scholar Thomas Young. He suggested a simple equation relating the contact angle between a liquid surface and a solid substrate to the interfacial tensions involved [1], γlg cos θ = γsg - γsl (1) In modern terms, γ denotes the excess free energy per unit area of the interface indicated by its indices, with l, g and s corresponding to the liquid, gas and solid, respectively [2]. After that, wetting seems to have been largely ignored by physicists for a long time. The discovery by Gabriel Lippmann that θ may be tuned over a wide range by electrochemical means [3], and some important papers about modifications of equation~(1) due to substrate inhomogeneities [4,5] are among the rare exceptions. This changed completely during the seventies, when condensed matter physics had become enthusiastic about critical phenomena, and was vividly inspired by the development of the renormalization group by Kenneth Wilson [6]. This had solved the long standing problem of how to treat fluctuations, and to understand the universal values of bulk critical exponents. By inspection of the critical exponents of the quantities involved in equation~(1), John W Cahn discovered what he called critical point wetting: for any liquid, there should be a well-defined transition to complete wetting (i.e., θ = 0) as the critical point of the liquid is approached along the coexistence curve [7]. His paper inspired an enormous amount of further work, and may be legitimately viewed as the entrance of wetting into the realm of modern physics. Most of the publications directly following Cahn's work were theoretical papers which elaborated on wetting in relation to critical phenomena. A vast amount of interesting, and in part quite unexpected, ramifications were discovered, such as the breakdown of universality in thin film systems [8]. Simultaneously, a number

  14. Contaminants in arctic snow collected over northwest Alaskan sea ice

    USGS Publications Warehouse

    Garbarino, J.R.; Snyder-Conn, E.; Leiker, T.J.; Hoffman, G.L.

    2002-01-01

    Snow cores were collected over sea ice from four northwest Alaskan Arctic estuaries that represented the annual snowfall from the 1995-1996 season. Dissolved trace metals, major cations and anions, total mercury, and organochlorine compounds were determined and compared to concentrations in previous arctic studies. Traces (<4 nanograms per liter, ng L-1) of cis- and trans-chlordane, dimethyl 2,3,5,6-tetrachloroterephthalate, dieldrin, endosulfan II, and PCBs were detected in some samples, with endosulfan I consistently present. High chlorpyrifos concentrations (70-80 ng L-1) also were estimated at three sites. The snow was highly enriched in sulfates (69- 394 mg L-1), with high proportions of nonsea salt sulfates at three of five sites (9 of 15 samples), thus indicating possible contamination through long-distance transport and deposition of sulfate-rich atmospheric aerosols. Mercury, cadmium, chromium, molybdenum, and uranium were typically higher in the marine snow (n = 15) in relation to snow from arctic terrestrial studies, whereas cations associated with terrigenous sources, such as aluminum, frequently were lower over the sea ice. One Kasegaluk Lagoon site (Chukchi Sea) had especially high concentrations of total mercury (mean = 214 ng L-1, standard deviation = 5 ng L-1), but no methyl mercury was detected above the method detection limit (0.036 ng L-1) at any of the sites. Elevated concentrations of sulfate, mercury, and certain heavy metals might indicate mechanisms of contaminant loss from the arctic atmosphere over marine water not previously reported over land areas. Scavenging by snow, fog, or riming processes and the high content of deposited halides might facilitate the loss of such contaminants from the atmosphere. Both the mercury and chlorpyrifos concentrations merit further investigation in view of their toxicity to aquatic organisms at low concentrations.

  15. Quantifying and comparing size selectivity among Alaskan sockeye salmon fisheries.

    PubMed

    Kendall, Neala W; Quinn, Thomas P

    2012-04-01

    Quantifying long-term size-selective harvest patterns is necessary for understanding the potential evolutionary effects on exploited species. The comparison of fishery selection patterns on the same species subject to different gear types, in different areas, and over multi-decadal periods can reveal the factors influencing selection. In this study we quantified and compared size-selective harvest by nine Alaskan sockeye salmon (Oncorhynchus nerka) fisheries to understand overall patterns. We calculated length-specific linear selection differentials (the difference in average length of fish before vs. after fishing), which are produced by different combinations of exploitation rates and length-selectivity values, and nonlinear standardized differentials, describing disruptive selection, across all years for each fishery. Selection differentials varied among years, but larger fish were caught in 73% of years for males and 84% of years for females, leaving smaller fish to spawn. Disruptive selection was observed on female and male fish in 84% and 92% of years, respectively. Linear selection was stronger on females than males in 77% of years examined, and disruptive selection was stronger on males in 71% of years. Selection pressure was influenced by a combination of factors under and beyond management control; analyses using mixed-effects models indicated that fisheries were less size selective in years when fish were larger than average and had lower exploitation rates. The observed harvest of larger than average sockeye salmon is consistent with the hypothesis that size-selective fishing contributes to decreasing age and length at maturation trends over time, but temporal variability in selection and strong disruptive selection suggests that the overall directional pressure is weaker than is often assumed in evolutionary models.

  16. Inorganic and organic contaminants in Alaskan shorebird eggs.

    PubMed

    Saalfeld, David T; Matz, Angela C; McCaffery, Brian J; Johnson, Oscar W; Bruner, Phil; Lanctot, Richard B

    2016-05-01

    Many shorebird populations throughout North America are thought to be declining, with potential causes attributed to habitat loss and fragmentation, reduced prey availability, increased predation, human disturbance, and increased exposure to environmental pollutants. Shorebirds may be particularly vulnerable to contaminant exposure throughout their life cycle, as they forage primarily on invertebrates in wetlands, where many contaminants accumulate disproportionately in the sediments. Therefore, it is important to document and monitor shorebird populations thought to be at risk and assess the role that environmental contaminants may have on population declines. To investigate potential threats and provide baseline data on shorebird contaminant levels in Alaskan shorebirds, contaminant concentrations were evaluated in shorebird eggs from 16 species residing in seven geographic distinct regions of Alaska. Similar to previous studies, low levels of most inorganic and organic contaminants were found, although concentrations of several inorganic and organic contaminants were higher than those of previous studies. For example, elevated strontium levels were observed in several species, especially black oystercatcher (Haematopus bachmani) sampled in Prince William Sound, Alaska. Additionally, contaminant concentrations varied among species, with significantly higher concentrations of inorganic contaminants found in eggs of pectoral sandpiper (Calidris melanotos), semipalmated sandpiper (Calidris pusilla), black oystercatcher, and bar-tailed godwit (Limosa lapponica). Similarly, significantly higher concentrations of some organic contaminants were found in the eggs of American golden plover (Pluvialis dominica), black-bellied plover (Pluvialis squatarola), pacific golden plover (Pluvialis fulva), bar-tailed godwit, and semipalmated sandpiper. Despite these elevated levels, current concentrations of contaminants in shorebird eggs suggest that breeding environments are

  17. Mechanisms influencing changes in lake area in Alaskan boreal forest

    USGS Publications Warehouse

    Roach, Jennifer K.; Griffith, Brad; Verbyla, David; Jones, Jeremy B.

    2011-01-01

    During the past ∼50 years, the number and area of lakes have declined in several regions in boreal forests. However, there has been substantial finer-scale heterogeneity; some lakes decreased in area, some showed no trend, and others increased. The objective of this study was to identify the primary mechanisms underlying heterogeneous trends in closed-basin lake area. Eight lake characteristics (δ18O, electrical conductivity, surface : volume index, bank slope, floating mat width, peat depth, thaw depth at shoreline, and thaw depth at the forest boundary) were compared for 15 lake pairs in Alaskan boreal forest where one lake had decreased in area since ∼1950, and the other had not. Mean differences in characteristics between paired lakes were used to identify the most likely of nine mechanistic scenarios that combined three potential mechanisms for decreasing lake area (talik drainage, surface water evaporation, and terrestrialization) with three potential mechanisms for nondecreasing lake area (subpermafrost groundwater recharge through an open talik, stable permafrost, and thermokarst). A priori expectations of the direction of mean differences between decreasing and nondecreasing paired lakes were generated for each scenario. Decreasing lakes had significantly greater electrical conductivity, greater surface : volume indices, shallower bank slopes, wider floating mats, greater peat depths, and shallower thaw depths at the forest boundary. These results indicated that the most likely scenario was terrestrialization as the mechanism for lake area reduction combined with thermokarst as the mechanism for nondecreasing lake area. Terrestrialization and thermokarst may have been enhanced by recent warming which has both accelerated permafrost thawing and lengthened the growing season, thereby increasing plant growth, floating mat encroachment, transpiration rates, and the accumulation of organic matter in lake basins. The transition to peatlands associated

  18. Inorganic and organic contaminants in Alaskan shorebird eggs.

    PubMed

    Saalfeld, David T; Matz, Angela C; McCaffery, Brian J; Johnson, Oscar W; Bruner, Phil; Lanctot, Richard B

    2016-05-01

    Many shorebird populations throughout North America are thought to be declining, with potential causes attributed to habitat loss and fragmentation, reduced prey availability, increased predation, human disturbance, and increased exposure to environmental pollutants. Shorebirds may be particularly vulnerable to contaminant exposure throughout their life cycle, as they forage primarily on invertebrates in wetlands, where many contaminants accumulate disproportionately in the sediments. Therefore, it is important to document and monitor shorebird populations thought to be at risk and assess the role that environmental contaminants may have on population declines. To investigate potential threats and provide baseline data on shorebird contaminant levels in Alaskan shorebirds, contaminant concentrations were evaluated in shorebird eggs from 16 species residing in seven geographic distinct regions of Alaska. Similar to previous studies, low levels of most inorganic and organic contaminants were found, although concentrations of several inorganic and organic contaminants were higher than those of previous studies. For example, elevated strontium levels were observed in several species, especially black oystercatcher (Haematopus bachmani) sampled in Prince William Sound, Alaska. Additionally, contaminant concentrations varied among species, with significantly higher concentrations of inorganic contaminants found in eggs of pectoral sandpiper (Calidris melanotos), semipalmated sandpiper (Calidris pusilla), black oystercatcher, and bar-tailed godwit (Limosa lapponica). Similarly, significantly higher concentrations of some organic contaminants were found in the eggs of American golden plover (Pluvialis dominica), black-bellied plover (Pluvialis squatarola), pacific golden plover (Pluvialis fulva), bar-tailed godwit, and semipalmated sandpiper. Despite these elevated levels, current concentrations of contaminants in shorebird eggs suggest that breeding environments are

  19. Exporting Alaskan North Slope crude oil: Benefits and costs

    SciTech Connect

    Not Available

    1994-06-01

    The Department of Energy study examines the effects of lifting the current prohibitions against the export of Alaskan North Slope (ANS) crude. The study concludes that permitting exports would benefit the US economy. First, lifting the ban would expand the markets in which ANS oil can be sold, thereby increasing its value. ANS oil producers, the States of California and Alaska, and some of their local governments all would benefit from increased revenues. Permitting exports also would generate new economic activity and employment in California and Alaska. The study concludes that these economic benefits would be achieved without increasing gasoline prices (either in California or in the nation as a whole). Lifting the export ban could have important implications for US maritime interests. The Merchant Marine Act of 1970 (known as the Jones Act) requires all inter-coastal shipments to be carried on vessels that are US-owned, US-crewed, and US-built. By limiting the shipment of ANS crude to US ports only, the export ban creates jobs for the seafarers and the builders of Jones Act vessels. Because the Jones Act does not apply to exports, however, lifting the ban without also changing US maritime law would jeopardize the jobs associated with the current fleet of Jones Act tankers. Therefore the report analyzes selected economic impacts of several maritime policy alternatives, including: Maintaining current law, which allows foreign tankers to carry oil where export is allowed; requiring exports of ANS crude to be carried on Jones Act vessels; and requiring exports of ANS crude to be carried on vessels that are US-owned and US-crewed, but not necessarily US-built. Under each of these options, lifting the export ban would generate economic benefits.

  20. WET SOLIDS FLOW ENHANCEMENT

    SciTech Connect

    Unknown

    2001-03-25

    The yield locus, tensile strength and fracture mechanisms of wet granular materials were studied. The yield locus of a wet material was shifted to the left of that of the dry specimen by a constant value equal to the compressive isostatic stress due to pendular bridges. for materials with straight yield loci, the shift was computed from the uniaxial tensile strength, either measured in a tensile strength tester or calculated from the correlation, and the angle of internal friction of the material. The predicted shift in the yield loci due to different moisture contents compare well with the measured shift in the yield loci of glass beads, crushed limestone, super D catalyst and Leslie coal. Measurement of the void fraction during the shear testing was critical to obtain the correct tensile strength theoretically or experimentally.

  1. Wet chemistry instrument prototype

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A wet chemistry instrument prototype for detecting amino acids in planetary soil samples was developed. The importance of amino acids and their condensation products to the development of life forms is explained. The characteristics of the instrument and the tests which were conducted to determine the materials compatibility are described. Diagrams are provided to show the construction of the instrument. Data obtained from the performance tests are reported.

  2. Wetting of Porous Solids.

    PubMed

    Patkar, Saket; Chaudhuri, Parag

    2013-01-10

    This paper presents a simple, three stage method to simulate the mechanics of wetting of porous solid objects, like sponges and cloth, when they interact with a fluid. In the first stage, we model the absorption of fluid by the object when it comes in contact with the fluid. In the second stage, we model the transport of absorbed fluid inside the object, due to diffusion, as a flow in a deforming, unstructured mesh. The fluid diffuses within the object depending on saturation of its various parts and other body forces. Finally, in the third stage, over-saturated parts of the object shed extra fluid by dripping. The simulation model is motivated by the physics of imbibition of fluids into porous solids in the presence of gravity. It is phenomenologically capable of simulating wicking and imbibition, dripping, surface flows over wet media, material weakening and volume expansion due to wetting. The model is inherently mass conserving and works for both thin 2D objects like cloth and for 3D volumetric objects like sponges. It is also designed to be computationally efficient and can be easily added to existing cloth, soft body and fluid simulation pipelines. PMID:23319518

  3. Wetting of porous solids.

    PubMed

    Patkar, Saket; Chaudhuri, Parag

    2013-09-01

    This paper presents a simple, three stage method to simulate the mechanics of wetting of porous solid objects, like sponges and cloth, when they interact with a fluid. In the first stage, we model the absorption of fluid by the object when it comes in contact with the fluid. In the second stage, we model the transport of absorbed fluid inside the object, due to diffusion, as a flow in a deforming, unstructured mesh. The fluid diffuses within the object depending on saturation of its various parts and other body forces. Finally, in the third stage, oversaturated parts of the object shed extra fluid by dripping. The simulation model is motivated by the physics of imbibition of fluids into porous solids in the presence of gravity. It is phenomenologically capable of simulating wicking and imbibition, dripping, surface flows over wet media, material weakening, and volume expansion due to wetting. The model is inherently mass conserving and works for both thin 2D objects like cloth and for 3D volumetric objects like sponges. It is also designed to be computationally efficient and can be easily added to existing cloth, soft body, and fluid simulation pipelines. PMID:23846102

  4. Contributions of algae to GPP and DOC production in an Alaskan fen: effects of historical water table manipulations on ecosystem responses to a natural flood.

    PubMed

    Wyatt, Kevin H; Turetsky, Merritt R; Rober, Allison R; Giroldo, Danilo; Kane, Evan S; Stevenson, R Jan

    2012-07-01

    The role of algae in the metabolism of northern peatlands is largely unknown, as is how algae will respond to the rapid climate change being experienced in this region. In this study, we examined patterns in algal productivity, nutrients, and dissolved organic carbon (DOC) during an uncharacteristically wet summer in an Alaskan rich fen. Our sampling was conducted in three large-scale experimental plots where water table position had been manipulated (including both drying and wetting plots and a control) for the previous 4 years. This study allowed us to explore how much ecosystem memory of the antecedent water table manipulations governed algal responses to natural flooding. Despite no differences in water table position between the manipulated plots at the time of sampling, algal primary productivity was consistently higher in the lowered water table plot compared to the control or raised water table plots. In all plots, algal productivity peaked immediately following seasonal maxima in nutrient concentrations. We found a positive relationship between algal productivity and water-column DOC concentrations (r (2) = 0.85, P < 0.001). Using these data, we estimate that algae released approximately 19% of fixed carbon into the water column. Algal exudates were extremely labile in biodegradability assays, decreasing by more than 55% within the first 24 h of incubation. We suggest that algae can be an important component of the photosynthetic community in boreal peatlands and may become increasingly important for energy flow in a more variable climate with more intense droughts and flooding.

  5. Projected future duration of the sea-ice-free season in the Alaskan Arctic

    NASA Astrophysics Data System (ADS)

    Wang, Muyin; Overland, James E.

    2015-08-01

    Global warming and continued reduction in sea ice cover will result in longer open water duration in the Arctic, which is important for the shipping industry, marine mammals, and other components of the regional ecosystem. In this study we assess the length of open water duration in the Alaskan Arctic over the next few decades using the set of latest coupled climate models (CMIP5). The Alaskan Arctic, including the Chukchi and the Beaufort Sea, has been a major region of summer sea ice retreat since 2007. Thirty five climate models from CMIP5 are evaluated and twelve are selected for composite projections based on their historical simulation performance. In the regions north of the Bering Strait (north of 70° N), future open-water duration shifts from a current 3-4 months to a projected near 5 months by 2040 based on the mean of the twelve selected climate models. There is considerable north-south gradient in projected durations. Open water duration is about 1 month shorter along the same latitudes in the Beaufort Sea compared with that in the Chukchi Sea. Uncertainty is generally ±1 month estimated from the range of model results. Open-water duration in the Alaskan Arctic expands quickly in these models over the next decades which will impact regional economic access and potentially alter ecosystems. Yet the northern Alaskan Arctic from January through May will remain sea ice covered into the second half of the century due to normal lack of sunlight.

  6. CYCLING OF DISSOLVED ELEMENTAL MERCURY IN ARCTIC ALASKAN LAKES. (R829796)

    EPA Science Inventory

    Aqueous production and water-air exchange of elemental mercury (Hg0) are important features of the environmental cycling of Hg. We investigated Hg0 cycling in ten Arctic Alaskan lakes that spanned a wide range in physicochemical characteristics. Dissolved...

  7. AlaskaAdvantage[R] Programs Annual Report to Alaskans, Year Ending June 30, 2007

    ERIC Educational Resources Information Center

    Alaska Commission on Postsecondary Education, 2007

    2007-01-01

    Through its AlaskAdvantage[R] Programs, the Alaska Commission on Postsecondary Education promotes, supports, and provides access to postsecondary education for Alaskans and in Alaska. This publication reports on another year of success for the state's higher education assistance agency. Among the accomplishments this year to make higher…

  8. Radiocarbon evidence of mid-Holocene mammoths stranded on an Alaskan Bering Sea island.

    PubMed

    Guthrie, R Dale

    2004-06-17

    Island colonization and subsequent dwarfing of Pleistocene proboscideans is one of the more dramatic evolutionary and ecological occurrences, especially in situations where island populations survived end-Pleistocene extinctions whereas those on the nearby mainland did not. For example, Holocene mammoths have been dated from Wrangel Island in northern Russia. In most of these cases, few details are available about the dynamics of how island colonization and extinction occurred. As part of a large radiocarbon dating project of Alaskan mammoth fossils, I addressed this question by including mammoth specimens from Bering Sea islands known to have formed during the end-Pleistocene sea transgression. One date of 7,908 +/- 100 yr bp (radiocarbon years before present) established the presence of Holocene mammoths on St Paul Island, a first Holocene island record for the Americas. Four lines of evidence--265 accelerator mass spectrometer (AMS) radiocarbon dates from Alaskan mainland mammoths, 13 new dates from Alaskan island mammoths, recent reconstructions of bathymetric plots and sea transgression rates from the Bering Sea--made it possible to reconstruct how mammoths became stranded in the Pribilofs and why this apparently did not happen on other Alaskan Bering Sea islands.

  9. American Indian/Alaskan Native Grandparents Raising Grandchildren: Findings from the Census 2000 Supplementary Survey

    ERIC Educational Resources Information Center

    Fuller-Thomson, Esme; Minkler, Meredith

    2005-01-01

    This article documents the prevalence and national profile of American Indian/Alaskan Native (AI/AN) grandparents who are raising their grandchildren, based on data from the American Community Survey/Census 2000 Supplementary Survey. In 2000 there were estimated to be nearly 53,000 AI/AN grandparent caregivers age 45 and older in the United…

  10. 36 CFR 223.10 - Free use to Alaskan settlers, miners, residents, and prospectors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST... may take free of charge green or dried timber from the National Forests in Alaska for personal use but... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Free use to Alaskan...

  11. 36 CFR 223.10 - Free use to Alaskan settlers, miners, residents, and prospectors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST... may take free of charge green or dried timber from the National Forests in Alaska for personal use but... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Free use to Alaskan...

  12. 36 CFR 223.10 - Free use to Alaskan settlers, miners, residents, and prospectors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER, SPECIAL FOREST... may take free of charge green or dried timber from the National Forests in Alaska for personal use but... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Free use to Alaskan...

  13. Alaskan Native Social Adjustment and the Role of Eskimo and Indian Music

    ERIC Educational Resources Information Center

    Johnston, Thomas F.

    1976-01-01

    Suggests that research into the social and psychological implications of Alaskan Eskimo and Indian musical behavior will continue to provide useful clues to solving current inter-cultural and intra-cultural problems in changing Alaska, particularly within the real of Eskimo and Indian preschool and primary education. (Author/AM)

  14. College Orientation Program for Alaskan Natives (COPAN Program - Education for Survival). Final Report.

    ERIC Educational Resources Information Center

    Salisbury, Lee H.

    Of the original number of Alaskan natives entering the University of Alaska from rural and urban areas, 50% drop out at the end of their freshman year, and less than 2% are likely to receive a degree at the end of 4 years. This high attrition rate is caused by poor elementary and secondary school preparation, and strong personal feelings of…

  15. Poly(hydroxyalkanoate) Biosynthesis from Crude Alaskan Pollock (Theragra chalcogramma) Oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Six strains of Pseudomonas were tested for their abilities to synthesize poly(hydroxyalkanoate) (PHA) polymers from crude Pollock oil, a large volume byproduct of the Alaskan fishing industry. All six strains were found to produce PHA polymers from hydrolyzed Pollock oil with productivities (P; the...

  16. Alaskan Fish Gelatin Films: Thermal, Tensile, and Barrier Properties and Effects of Cross-linking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gelatin was extracted from the skins of Alaska pollock (Theragra chalcogramma) and Alaska pink salmon (Oncorhynchus gorbuscha). These skins were by-products generated from the Alaskan fishing industry. Films were then cast from the fish gelatin and their thermal, tensile, water vapor permeability, o...

  17. Understanding the Complex Dimensions of the Digital Divide: Lessons Learned in the Alaskan Arctic

    ERIC Educational Resources Information Center

    Subramony, Deepak Prem

    2007-01-01

    An ethnographic case study of Inupiat Eskimo in the Alaskan Arctic has provided insights into the complex nature of the sociological issues surrounding equitable access to technology tools and skills, which are referred to as the digital divide. These people can overcome the digital divide if they get the basic ready access to hardware and…

  18. Alaska Is Our Home--Book 2: A Natural Science Handbook for Alaskan Students.

    ERIC Educational Resources Information Center

    Bury, John; Bury, Susan

    A natural science resource booklet for teachers and students contains detailed materials for teaching and learning about Alaskan wildlife. Each of nine chapters provides background subject information, suggested learning activities, tear-out pages of review questions for students to answer, and supplementary notes for teachers which include…

  19. Intensive Evaluation of Satellite TV Impact on Four Alaskan Villages. Supplement to Basic ESCD Evaluation Design.

    ERIC Educational Resources Information Center

    Practical Concepts, Inc., Washington, DC.

    A supplement to the final report, "Design for an Analysis and Assessment of the Education Satellite Communications Demonstration (ESCD)," this document is both: (1) a separable, sociologically oriented evaluation of the ESCD impact on Alaskan native villages; and (2) a direct extension of the work described in sections 4 and 5 in the Practical…

  20. It Happens When We Get There. Conversations With Teachers in Alaskan Villages.

    ERIC Educational Resources Information Center

    Beers, C. David

    Developed through in-depth interviews with experienced "bush" teachers from interior Alaska, this booklet is the product of a five-day workshop in the design of vocational education curriculum materials for rural Alaskan secondary schools. The statements in this booklet represent the edited responses of experienced teachers to the following…

  1. Studies of the Northern Alaskan Coastal System: Ongoing project work and synthesis activities

    NASA Astrophysics Data System (ADS)

    Douglas, T. A.; Sturm, M.; Ashjian, C. J.; Jorgensen, T.; Oechel, W. C.; Ping, C.; Rhew, R. C.; Stieglitz, M.

    2006-12-01

    Six ongoing projects focus on a better understanding of processes occurring along the Arctic Alaskan Coast. These projects, grouped as "Studies of the Northern Alaskan Coastal System", or SNACS, combine field, laboratory, modeling and human dimensions research. They include: 1) an investigation of climate variability, ocean processes, sea ice, bowhead whales, and Inupiat subsistence whaling, 2) research on the impact of variability within the ocean and atmosphere on terrestrial fluxes of carbon dioxide, dissolved organic matter and energy, 3) an inventory and description of soil organic carbon fluxes and ground ice in the coastal environment, 4) a determination of whether arctic coastal terrestrial ecosystems are significant sources or sinks of atmospheric methyl halides, chloroform and methane, 5) development of generalized discharge- constituent relationships for arctic basins, and 6) an investigation of the processes controlling mercury deposition to the coastal system. Three broad themes unite the projects: 1) nutrient fluxes from rivers and shoreline erosion in the Arctic coastal zone, 2) impacts of cryospheric changes on the Alaskan Arctic Coast, and 3) potential rapid regime shifts controlled by atmospheric and meteorological processes that could affect the Alaskan Arctic Coast. Warming of the Arctic, particularly its impact on sea ice and nutrient transport in arctic rivers is already affecting fundamental coastal system processes. The six SNACS projects are helping to understand how these impacts will evolve and what their ramifications will be both within and outside of the Arctic.

  2. EXAMINATION OF THE FEASIBILITY FOR DEMONSTRATION AND USE OF RADIOLUMINESCENT LIGHTS FOR ALASKAN REMOTE RUNWAY LIGHTING

    SciTech Connect

    Jensen, G.; Perrigo, L.; Leonard, L.; Hegdal, L

    1984-01-01

    This report examines the feasibility of radioluminescent light applications for rural Alaskan airports. The work presented in this report covers four tasks: State of the Art Evaluation of Radioluminescent Lights, Environmental, Radiological, and Regulatory Evaluations, Engineering Evaluations, and Demonstration Plan Development.

  3. Petroleum systems of the Alaskan North Slope: a numerical journey from source to trap

    USGS Publications Warehouse

    Lampe, C.; Peters, K.E.; Magoon, L.B.; Bird, K.J.; Lillis, P.G.

    2003-01-01

    The complex petroleum province of the Alaskan North Slope contains six petroleum systems (Magoon and others, this session). Source rocks for four of these systems include the Hue-gamma ray zone (Hue-GRZ), pebble shale unit, Kingak Shale, and Shublik Formation. Geochemical data for these source rocks are investigated in greater detail and provide the basis for numerical petroleum migration models.

  4. Alaskan glaciers: Recent observations in respect to the earthquake-advance theory

    USGS Publications Warehouse

    Post, A.S.

    1965-01-01

    Preliminary aerial photographic studies indicate that the Alaskan earthquake produced some rockfalls but no significant snow and ice avalanches on glaciers. No rapid, short-lived glacier advances (surges) are conclusively associated with this earthquake. Recent evidence fails to support the earthquake-advance theory of Tarr and Martin.

  5. Shaping the Landscape: A Journal of Writing by Alaskan Teachers 1992.

    ERIC Educational Resources Information Center

    Longenbaugh, Betsy, Ed.

    Intended to encourage Alaska teachers to write, to provide an honest sounding board for those submitting work, and to be a pleasure to read, this booklet presents a collection of 20 pieces of writing (short stories, poems, and life experiences) by Alaskan teachers. The pieces and their authors are as follows: "The First Haiku" (Dan Walker);…

  6. Implications of lifting the ban on the export of Alaskan crude oil

    SciTech Connect

    Not Available

    1990-03-26

    Present legislation effectively bans the export of crude oil produced in the United States. The ban has been in effect for years and is particularly stringent with respect to crude oil produced in Alaska, particularly on the North Slope. The Alaska crude export ban is specifically provided for in the Trans-Alaska Pipeline Authorization Act of 1973 and in other legislation. It was imposed for two reasons. The first was to reduce US dependence on imported crude oil. The Arab oil embargo had been imposed shortly before the Act was passed and a greater measure of energy independence was considered imperative at that time. The second reason was to assure that funds expended in building an Alaskan pipeline would benefit domestic users rather than simply employed to facilitate shipments to other countries. The main objective of this report is to estimate the potential impacts on crude oil prices that would result from lifting the export ban Alaskan crude oil. The report focuses on the Japanese market and the US West Coast market. Japan is the principal potential export market for Alaskan crude oil. Exports to that market would also affect the price of Alaskan crude oil as well as crude oil and product prices on the West Coast and the volume of petroleum imported in that area. 3 figs., 8 tabs.

  7. 77 FR 45921 - Alaskan Fuel Hauling as a Restricted Category Special Purpose Flight Operation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-02

    ... the Federal Register (74 FR 39242) in which the FAA proposed to specify Alaskan fuel hauling as a... Purpose Flight Operation AGENCY: Federal Aviation Administration (FAA), (DOT). ACTION: Notice of policy... submitted was, ``The transport of the fuel could be made safer by limiting the payload on each flight to...

  8. Alaskan Native Games--A Cross-Cultural Addition to the Physical Education Curriculum.

    ERIC Educational Resources Information Center

    Frey, Richard D.; Allen, Mike

    1989-01-01

    Importing traditional, yet unknown, physical activities from different cultures is an exciting way to add creativity and imagination to the physical education curriculum. Explanations, accompanied by teaching hints, are given of several traditional Alaskan native games which have been successfully used with K-Six students in the Anchorage School…

  9. Controls on Ecosystem and Root Respiration in an Alaskan Peatland

    NASA Astrophysics Data System (ADS)

    McConnell, N. A.; McGuire, A. D.; Harden, J. W.; Kane, E. S.; Turetsky, M. R.

    2010-12-01

    Boreal ecosystems cover 14% of the vegetated surface on earth and account for 25-30% of the world’s soil carbon (C), mainly due to large carbon stocks in deep peat and frozen soil layers. While peatlands have served as historical sinks of carbon, global climate change may trigger re-release of C to the atmosphere and may turn these ecosystems into net C sources. Rates of C release from a peatland are determined by regional climate and local biotic and abiotic factors such as vegetation cover, thaw depth, and peat thickness. Soil CO2 fluxes are driven by both autotrophic (plant) respiration and heterotrophic (microbial) respiration. Thus, changes in plant and microbial activity in the soil will impact CO2 emissions from peatlands. In this study, we explored environmental and vegetation controls on ecosystem respiration and root respiration in a variety of wetland sites. The study was conducted at the Alaskan Peatland Experiment (APEX; www.uoguelph.ca/APEX) sites in the Bonanza Creek Experimental Forest located 35 km southwest of Fairbanks Alaska. We measured ecosystem respiration, root respiration, and monitored a suite of environmental variables along a vegetation and soil moisture gradient including a black spruce stand with permafrost, a shrubby site with permafrost, a tussock grass site, and a herbaceous open rich fen. Within the rich fen, we have been conducting water table manipulations including a control, lowered, and raised water table treatment. In each of our sites, we measured total ecosystem respiration using static chambers and root respiration by harvesting roots from the uppermost 20 cm and placing them in a root cuvette to obtain a root flux. Ecosystem respiration (ER) on a μmol/m2/sec basis varied across sites. Water table was a significant predictor of ER at the lowered manipulation site and temperature was a strong predictor at the control site in the rich fen. Water table and temperature were both significant predictors of ER at the raised

  10. Seasonal Variations of Biomass Burning Tracers in Alaskan Aerosols

    NASA Astrophysics Data System (ADS)

    Haque, M. M.; Kawamura, K.; Kim, Y.

    2015-12-01

    Biomass burning (BB) is a large source of atmospheric trace gases and aerosols. During the burning, several organic and inorganic gases and particles are emitted into the atmosphere. Here, we present seasonal variations of specific BB tracers such as levoglucosan, mannosan and galactosan, which are produced by pyrolysis of cellulose and hemicelluloses. We collected TSP aerosol samples (n= 32) from Fairbanks, Alaska in June 2008 to June 2009. Levoglucosan was detected as the dominant anhydrosugar followed by its isomers, mannosan and galactosan. The result of levoglucosan showed clear seasonal trends with winter maximum (ave.145 ng m-3) and spring minimum (12.3 ng m-3). The analyses of air mass back trajectories and fire spots demonstrated that anhydrosugars may be associated from residential heating and cooking in local region and Siberia in winter time. Levoglucosan showed significant positive correlation with EC (r= 0.67, p= 0.001) and OC (r= 0.51, p= 0.002) but there was no correlation with nss-K+ (r= -0.16, p= 0.37). The emission of K+ from biomass burning depends on burning condition and types of material burned. There are two possible reasons, which can be explained for the lack of correlation between levoglucosan and K+. First, specific burning materials may be used for residential heating, which can't produce K+. Secondly, K+ could be deposit on the surface of chimney breast and it can't emit into the atmosphere. Anhydrosugars contributed 4.4% to water-soluble organic carbon (WSOC) and 2.4% to organic carbon (OC). Their highest values of WSOC (8.1%) and OC (4.9%) in wintertime indicate that contribution of BB to Alaskan aerosols is important in winter period. The current study presents for the first time one-year observation on BB tracers in the subarctic region, which provide useful information to better understand the effect of biomass burning on subarctic atmosphere. It will also be helpful for further long-term climate studies in this region.

  11. Wet-dog shake

    NASA Astrophysics Data System (ADS)

    Dickerson, Andrew; Mills, Zack; Hu, David

    2010-11-01

    The drying of wet fur is a critical to mammalian heat regulation. We investigate experimentally the ability of hirsute animals to rapidly oscillate their bodies to shed water droplets, nature's analogy to the spin cycle of a washing machine. High-speed videography and fur-particle tracking is employed to determine the angular position of the animal's shoulder skin as a function of time. We determine conditions for drop ejection by considering the balance of surface tension and centripetal forces on drops adhering to the animal. Particular attention is paid to rationalizing the relationship between animal size and oscillation frequency required to self-dry.

  12. Wetting in Color

    NASA Astrophysics Data System (ADS)

    Burgess, Ian Bruce

    Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. However, expansion of colorimetry to new sensing paradigms is challenging because macroscopic color changes are seldom coupled to arbitrary differences in the physical/chemical properties of a system. In this thesis I present in detail the development of Wetting in Color Technology, focusing primarily on its application as an inexpensive and highly selective colorimetric indicator for organic liquids. The technology exploits chemically-encoded inverse-opal photonic crystals to control the infiltration of fluids to liquid-specific spatial patterns, projecting minute differences in liquids' wettability to macroscopically distinct, easy-to-visualize structural color patterns. It is shown experimentally and corroborated with theoretical modeling using percolation theory that the high selectivity of wetting, upon-which the sensitivity of the indicator relies, is caused by the highly symmetric structure of our large-area, defect-free SiO2 inverse-opals. The regular structure also produces a bright iridescent color, which disappears when infiltrated with liquid - naturally coupling the optical and fluidic responses. Surface modification protocols are developed, requiring only silanization and selective oxidation, to facilitate the deterministic design of an indicator that differentiates a broad range of liquids. The resulting tunable, built-in horizontal and vertical chemistry gradients allow the wettability threshold to be tailored to specific liquids across a continuous range, and make the readout rely only on countable color differences. As wetting is a generic fluidic phenomenon, Wetting in Color technology could be suitable for applications in authentication or identification of unknown liquids across a broad range of industries. However, the generic nature of the response also ensures chemical non-specificity. It is shown

  13. Phoenix's Wet Chemistry Lab

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is an illustration of soil analysis on NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL will attempt to determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  14. Phoenix's Wet Chemistry Lab

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is an illustration of the analytical procedure of NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL can determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  15. Optical wet steam monitor

    DOEpatents

    Maxey, L.C.; Simpson, M.L.

    1995-01-17

    A wet steam monitor determines steam particle size by using laser doppler velocimeter (LDV) device to produce backscatter light. The backscatter light signal is processed with a spectrum analyzer to produce a visibility waveform in the frequency domain. The visibility waveform includes a primary peak and a plurality of sidebands. The bandwidth of at least the primary frequency peak is correlated to particle size by either visually comparing the bandwidth to those of known particle sizes, or by digitizing the waveform and comparing the waveforms electronically. 4 figures.

  16. Optical wet steam monitor

    DOEpatents

    Maxey, Lonnie C.; Simpson, Marc L.

    1995-01-01

    A wet steam monitor determines steam particle size by using laser doppler velocimeter (LDV) device to produce backscatter light. The backscatter light signal is processed with a spectrum analyzer to produce a visibility waveform in the frequency domain. The visibility waveform includes a primary peak and a plurality of sidebands. The bandwidth of at least the primary frequency peak is correlated to particle size by either visually comparing the bandwidth to those of known particle sizes, or by digitizing the waveform and comparing the waveforms electronically.

  17. WET SOLIDS FLOW ENHANCEMENT

    SciTech Connect

    Hugo S. Caram; Natalie Foster

    1997-03-31

    The objective was to visualize the flow of granular materials in flat bottomed silo. This was done by for dry materials introducing mustard seeds and poppy seeds as tracer particles and imaging them using Nuclear Magnetic Resonance. The region sampled was a cylinder 25 mm in diameter and 40 mm in length. Eight slices containing 128*128 to 256*256 pixels were generated for each image. The size of the silo was limited by the size of the high resolution NMR imager available. Cross-sections of 150mm flat bottomed silos, with the tracer layers immobilized by a gel, showed similar qualitative patterns for both dry and wet granular solids.

  18. Wet granular materials

    NASA Astrophysics Data System (ADS)

    Mitarai, Namiko; Nori, Franco

    2006-04-01

    Most studies on granular physics have focused on dry granular media, with no liquids between the grains. However, in geology and many real world applications (e.g. food processing, pharmaceuticals, ceramics, civil engineering, construction, and many industrial applications), liquid is present between the grains. This produces inter-grain cohesion and drastically modifies the mechanical properties of the granular media (e.g. the surface angle can be larger than 90 degrees). Here we present a review of the mechanical properties of wet granular media, with particular emphasis on the effect of cohesion. We also list several open problems that might motivate future studies in this exciting but mostly unexplored field.

  19. Deglacial Warming and Wetting of Northern Alaska

    NASA Astrophysics Data System (ADS)

    Daniels, W.; Russell, J. M.; Longo, W. M.; Giblin, A. E.; Holland-Stergar, P.; Morrill, C.; Huang, Y.

    2015-12-01

    Aeolian sand dunes swept across northern Alaska during the last glacial maximum. Today, summer temperatures are moderate and soils can remain waterlogged all summer long. How did the transition from a cold and dry glacial to a warm and wet interglacial take place? To answer this question we reconstructed temperature and precipitation changes during the last deglaciation using biomarker hydrogen isotopes from a new 28,000 year-long sediment core from Lake E5, located in the central Brooks Range of Alaska. We use terrestrial leaf waxes (dDterr, C28-acid), informed by dD measurements of modern vegetation, to infer dD of precipitation, an indicator of relative temperature change. Biomarkers from aquatic organisms (dDaq, C18-acid) are used as a proxy for lake water isotopes. The offset between the two (eterr-aq) is used to infer relative changes in evaporative enrichment of lake water, and by extension, moisture balance. dDterr during the last glacial period was -282‰ compared to -258‰ during the Holocene, suggesting a 5.6 ± 2.7 °C increase in summer temperature using the modern local temperature-dD relationship. Gradual warming began at ~18.5 ka, and temperature increased abruptly at 11.5 ka, at the end of the Younger Dryas. Warming peaked in the early Holocene from 11.5 to 9.1 ka, indicating a Holocene thermal maximum associated with peak summer insolation. The eterr-aq supports a dry LGM and moist Holocene. Other sediment proxies (TIC, TOC, redox-sensitive elements) support the eterr-aq, and reveal a shift to more positive P-E beginning around 17 ka, suggesting rising temperature led increases in precipitation during the last deglaciation. Moreover, differing patterns of dDterr and eterr-aq during the deglaciation suggest that the relationship between temperature and precipitation changed through time. Such decoupling, likely due to regional atmospheric reorganization as the Laurentide ice sheet waned, illustrates the importance of atmospheric dynamics in

  20. PREFACE: Wetting: introductory note

    NASA Astrophysics Data System (ADS)

    Herminghaus, S.

    2005-03-01

    The discovery of wetting as a topic of physical science dates back two hundred years, to one of the many achievements of the eminent British scholar Thomas Young. He suggested a simple equation relating the contact angle between a liquid surface and a solid substrate to the interfacial tensions involved [1], γlg cos θ = γsg - γsl (1) In modern terms, γ denotes the excess free energy per unit area of the interface indicated by its indices, with l, g and s corresponding to the liquid, gas and solid, respectively [2]. After that, wetting seems to have been largely ignored by physicists for a long time. The discovery by Gabriel Lippmann that θ may be tuned over a wide range by electrochemical means [3], and some important papers about modifications of equation~(1) due to substrate inhomogeneities [4,5] are among the rare exceptions. This changed completely during the seventies, when condensed matter physics had become enthusiastic about critical phenomena, and was vividly inspired by the development of the renormalization group by Kenneth Wilson [6]. This had solved the long standing problem of how to treat fluctuations, and to understand the universal values of bulk critical exponents. By inspection of the critical exponents of the quantities involved in equation~(1), John W Cahn discovered what he called critical point wetting: for any liquid, there should be a well-defined transition to complete wetting (i.e., θ = 0) as the critical point of the liquid is approached along the coexistence curve [7]. His paper inspired an enormous amount of further work, and may be legitimately viewed as the entrance of wetting into the realm of modern physics. Most of the publications directly following Cahn's work were theoretical papers which elaborated on wetting in relation to critical phenomena. A vast amount of interesting, and in part quite unexpected, ramifications were discovered, such as the breakdown of universality in thin film systems [8]. Simultaneously, a number

  1. Rheological conditions for emplacement of Ural-Alaskan-type ultramafic complexes

    NASA Astrophysics Data System (ADS)

    Guillou-Frottier, Laurent; Burov, Evgueni; Augé, Thierry; Gloaguen, Eric

    2014-09-01

    Ural-Alaskan- (or Alaskan-) type complexes correspond to a particular class of ultramafic intrusions that attract particular attention due to their deep mantle origin and their platinum-group element (PGE) mineralization. When defined as massifs of dunite-clinopyroxenite, only forty-six complexes are reported in the literature. These large-scale dunite pipe-like structures are rarely isolated and they even can appear in clusters. To better understand genesis of these relatively young (< 460 Ma) complexes, a worldwide compilation has been built, and three categories have been defined: single circular or elliptical bodies, twin bodies with similar shapes, and dismembered dunite bodies. PGE enrichment in Alaskan-type complexes is highest for the second category, where twin bodies are interpreted as horizontal sections of Y-shaped dunite pipes. To constrain mechanical properties of the lithosphere allowing emplacement of the Alaskan-type complexes, the forceful diapiric ascent hypothesis is investigated through numerical thermo-mechanical models. One hundred high resolution experiments accounting for realistic phase changes and softening mechanisms have been performed. The experiments show that with no rheological softening of the host rock and in case of a relatively weak ductile lower crust, the uprising magma tends to spread laterally without reaching the surface. To account for the forceful ascent of deep magmas, it is hence necessary to assume a strong lower crust rheology and strong local softening mechanisms. Besides reproducing the clustered distribution of the weakness zones representing magma pathways, these latter experiments reproduce large-scale pipe-like (cylindrical) structures, Y-shaped and funnel-shaped bodies, and laterally-shifted structures. Interestingly, zones of highest strain rates are located at the bottom parts of the inclined edges of Y-shaped and funnel-shaped bodies. The restricted age range of Alaskan-type complexes (< 460 Ma) would mean

  2. Wetting of cholesteric liquid crystals.

    PubMed

    Silvestre, Nuno M; Figueirinhas Pereira, Maria Carolina; Bernardino, Nelson R; Telo da Gama, Margarida M

    2016-02-01

    We investigate theoretically the wetting properties of cholesteric liquid crystals at a planar substrate. If the properties of substrate and of the interface are such that the cholesteric layers are not distorted, the wetting properties are similar to those of a nematic liquid crystal. If, on the other hand, the anchoring conditions force the distortion of the liquid crystal layers the wetting properties are altered, the free cholesteric-isotropic interface is non-planar and there is a layer of topological defects close to the substrate. These deformations can either promote or hinder the wetting of the substrate by a cholesteric, depending on the properties of the cholesteric liquid crystal.

  3. Wet solids flow enhancemant

    SciTech Connect

    Caram, H.S.; Foster, N.; Wildman, D.J.

    1996-12-31

    WE used glass beads of different sizes as.a model system to study the flow enhancing properties of Octadecyltrichlorosilane (OTS). 0TS provides Si(CH{sub 2}){sub 17}CH{sub 3} groups that bind with the surface hydrox groups to make it hydrophobic. Experimental data showed, indeed, that surface hydrophobicity promotes the flow of wet granular materials. Mixtures of different percentage of silanized/unsilanized particles were prepared for tensile strength measurements. The tensile strength decreased as more silanized particles were added to the samples. The relationship between dimensionless tensile strength and void fraction followed the correlation found by Pierrat (1994). Contact angles were larger for the silanized particles, as compared with unsilanized ones.

  4. Impact of disability and other physical health issues on academic outcomes among American Indian and Alaskan Native college students: an exploratory analysis.

    PubMed

    Patterson Silver Wolf Adelv Unegv Waya, David A; Vanzile-Tamsen, Carol; Black, Jessica; Billiot, Shanondora M; Tovar, Molly

    2015-01-01

    This study investigated whether self-identified disabilities among American Indian and Alaskan Native college students impact academic performance and persistence to graduation and explored the differences in health and academic grades between American Indian and Alaskan Native students and students of other racial and ethnic identities using the National College Health Assessment. Findings indicate that American Indian or Alaskan Native students have significantly lower grades than White and Asian students, and American Indian and Alaskan Native women report the highest incidence of health problems of any demographic group. Exploratory results point to future research to determine the full impact of disabilities and poor health on academic success.

  5. Claviceps cyperi, a new cause of severe ergotism in dairy cattle consuming maize silage and teff hay contaminated with ergotised Cyperus esculentus (nut sedge) on the Highveld of South Africa.

    PubMed

    Naudè, T W; Botha, C J; Vorster, J H; Roux, C; Van der Linde, E J; Van der Walt, S I; Rottinghaus, G E; Van Jaarsveld, L; Lawrence, A N

    2005-03-01

    During December/January 1996/97 typical summer syndrome (hyperthermia and a 30% drop in milk yield) occurred in succession in two Holstein dairy herds (n=240 and n=150 milking cows, respectively) on the South African Highveld. These farms are situated in the midst of the prime maize and dairy farming areas of South Africa where this condition had never been diagnosed before. The individual components of the concentrate on both farms were negative for ergot alkaloids. Endophytic fungi and/or ergot infestation of teff and other grasses fed to the cows were then suspected of being involved, but neither endophytes nor ergot alkaloids could be implicated from these sources. By measuring the serum prolactin levels of groups of sheep (n=5) fed the first farm's total mixed ration (TMR) or its three individual fibre components for a period of 11 days, the source of the ergot alkaloids was identified. A statistically significant decrease in the level of this hormone occurred only in the group on maize silage (which constituted 28% on dry matter base of the TMR). The involvement of the maize silage was further chemically confirmed by the high levels of total ergot alkaloids, predominantly ergocryptine, found by LC-MS in the silage as well as in the TMR (115-975 ppb and 65-300 ppb, respectively). The ergot alkaloid content (mainly ergocryptine) of the maize silage on the second affected farm was 875 ppb. Withdrawal of contaminated silage resulted in gradual recovery of stock on both farms. Nut sedge (Cyperus esculentus and Cyperus rotundus of the family Cyperaceae) has a world-wide distribution and is a common weed in annual crops, and can be parasitized by Claviceps cyperi. Careful examination of the maize silage from both farms revealed that it was heavily contaminated with nut sedge and that it contained minute sclerotia, identified as those of Claviceps cyperi, originating from the latter. Nut sedge was abundant on both farms and it is believed that late seasonal rain had

  6. Claviceps cyperi, a new cause of severe ergotism in dairy cattle consuming maize silage and teff hay contaminated with ergotised Cyperus esculentus (nut sedge) on the Highveld of South Africa.

    PubMed

    Naudè, T W; Botha, C J; Vorster, J H; Roux, C; Van der Linde, E J; Van der Walt, S I; Rottinghaus, G E; Van Jaarsveld, L; Lawrence, A N

    2005-03-01

    During December/January 1996/97 typical summer syndrome (hyperthermia and a 30% drop in milk yield) occurred in succession in two Holstein dairy herds (n=240 and n=150 milking cows, respectively) on the South African Highveld. These farms are situated in the midst of the prime maize and dairy farming areas of South Africa where this condition had never been diagnosed before. The individual components of the concentrate on both farms were negative for ergot alkaloids. Endophytic fungi and/or ergot infestation of teff and other grasses fed to the cows were then suspected of being involved, but neither endophytes nor ergot alkaloids could be implicated from these sources. By measuring the serum prolactin levels of groups of sheep (n=5) fed the first farm's total mixed ration (TMR) or its three individual fibre components for a period of 11 days, the source of the ergot alkaloids was identified. A statistically significant decrease in the level of this hormone occurred only in the group on maize silage (which constituted 28% on dry matter base of the TMR). The involvement of the maize silage was further chemically confirmed by the high levels of total ergot alkaloids, predominantly ergocryptine, found by LC-MS in the silage as well as in the TMR (115-975 ppb and 65-300 ppb, respectively). The ergot alkaloid content (mainly ergocryptine) of the maize silage on the second affected farm was 875 ppb. Withdrawal of contaminated silage resulted in gradual recovery of stock on both farms. Nut sedge (Cyperus esculentus and Cyperus rotundus of the family Cyperaceae) has a world-wide distribution and is a common weed in annual crops, and can be parasitized by Claviceps cyperi. Careful examination of the maize silage from both farms revealed that it was heavily contaminated with nut sedge and that it contained minute sclerotia, identified as those of Claviceps cyperi, originating from the latter. Nut sedge was abundant on both farms and it is believed that late seasonal rain had

  7. REPETITIVE DIGITAL NOAA-AVHRR DATA FOR ALASKAN ENGINEERING AND SCIENTIFIC APPLICATIONS.

    USGS Publications Warehouse

    Christie, William M.; Pawlowski, Robert J.; Fleming, Michael D.

    1986-01-01

    Selected digitally enhanced NOAA - Advanced Very High Resolution Radiometer (AVHRR) images taken by the NOAA 6, 7, 8 and 9 Polar Orbiting Satellites demonstrate the capability and application of repetitive low-resolution satellite data to Alaska's engineering and science community. Selected cloud-free visible and thermal infrared images are enhanced to depict distinct oceanographic and geologic processes along Alaska's west coast and adjacent seas. Included are the advance of the Bering Sea ice field, transport of Yukon River sediment into Norton Sound, and monitoring of plume trajectories from the Mount Augustine volcanic eruptions. Presented illustrations are representative of the 94 scenes in a cooperative USGS EROS/NOAA Alaskan AVHRR Digital Archive. This paper will discuss the cooperative efforts in establishing the first year data set and identifying Alaskan applications.

  8. Preliminary evidence for the involvement of budding bacteria in the origin of Alaskan placer gold

    USGS Publications Warehouse

    Watterson, J.R.

    1992-01-01

    Lacelike networks of micrometre-size filiform gold associated wtih Alaskan placer gold particles are interpreted as low-temperature pseudomorphs of a Pedomicrobium-like budding bacterium. Submicron reproductive structures (hyphae) and other morphological features similar to those of Pedomicrobium manganicum occur as detailed three-dimensional facsimiles in high purity gold in and on placer gold particles from Lillian Creek, Alaska. In a scanning electron microscope survey, the majority of gold particles at nine Alaskan placer deposits appear to include gold that has accumulated chemically at low temperatures in and on the cells of P. manganicum. Similar bacterioform gold from a Paleozoic deposit in China and from the Precambrian Witwatersrand deposit in South Africa may indicate that bacterioform gold is widespread. -Author

  9. Wet Winding Improves Coil Encapsulation

    NASA Technical Reports Server (NTRS)

    Hill, A. J.

    1987-01-01

    Wet-winding process encapsulates electrical coils more uniformily than conventional processes. Process requires no vacuum pump and adapts easily to existing winding machines. Encapsulant applied to each layer of wire as soon as added to coil. Wet-winding process eliminates voids, giving more uniformly encapsulated coil.

  10. Extensive wetting due to roughness

    SciTech Connect

    Yost, F.G.; Michael, J.R.; Eisenmann, E.T. . Center for Solder Science and Technology)

    1995-01-01

    Typically, a small mass of eutectic Sn-Pb solder wets a copper surface and flows radially outward to form a hemispherical shape with a contact angle of approx. 15--20 deg. When a similar mass of solder wets and thick electroless copper coated substrate, rapid radial flow commences and surprising new effects occur. Thick coats of electroless copper have a nodular surface structure and spreading on it does not subside until all solder is consumed. When the nodular structure is wetted by solder a coastline'' with many nearby islands'' are defined. Photos of regions at the wetting front were taken in the backscatter imaging mode of an SEM. These images show that solder wets the valleys between the surface nodules forming a delicate, lacy arrangement. The geometry of this coastal'' solder structure is described as fractal-like having a dimension D = 1.38 making it similar to drying fronts and cloud configurations. The importance of surface roughness in wetting phenomena is discussed in the light of an extensive history on the subject. It is shown that for spontaneous flow, assisted by roughness, the surface geometry must consist of local angles that are larger than the equilibrium contact angle. Kinetics of the wetting process are demonstrated by image analysis of wetted area taken from videotaped experiments. These experimental kinetics are shown to be similar in form to flow in open channel capillaries.

  11. Clinical pathology and assessment of pathogen exposure in southern and Alaskan sea otters.

    PubMed

    Hanni, Krista D; Mazet, Jonna A K; Gulland, Frances M D; Estes, James; Staedler, Michelle; Murray, Michael J; Miller, Melissa; Jessup, David A

    2003-10-01

    The southern sea otter (Enhydra lutris nereis) population in California (USA) and the Alaskan sea otter (E. lutris kenyoni) population in the Aleutian Islands (USA) chain have recently declined. In order to evaluate disease as a contributing factor to the declines, health assessments of these two sea otter populations were conducted by evaluating hematologic and/or serum biochemical values and exposure to six marine and terrestrial pathogens using blood collected during ongoing studies from 1995 through 2000. Samples from 72 free-ranging Alaskan, 78 free-ranging southern, and (for pathogen exposure only) 41 debilitated southern sea otters in rehabilitation facilities were evaluated and compared to investigate regional differences. Serum chemistry and hematology values did not indicate a specific disease process as a cause for the declines. Statistically significant differences were found between free-ranging adult southern and Alaskan population mean serum levels of creatinine kinase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, calcium, cholesterol, creatinine, glucose, phosphorous, total bilirubin, blood urea nitrogen, and sodium. These were likely due to varying parasite loads, contaminant exposures, and physiologic or nutrition statuses. No free-ranging sea otters had signs of disease at capture, and prevalences of exposure to calicivirus, Brucella spp., and Leptospira spp. were low. The high prevalence (35%) of antibodies to Toxoplasma gondii in free-ranging southern sea otters, lack of antibodies to this parasite in Alaskan sea otters, and the pathogen's propensity to cause mortality in southern sea otters suggests that this parasite may be important to sea otter population dynamics in California but not in Alaska. The evidence for exposure to pathogens of public health importance (e.g., Leptospira spp., T. gondii) in the southern sea otter population, and the naïveté of both populations to other pathogens (e.g., morbillivirus

  12. Clinical pathology and assessment of pathogen exposure in southern and Alaskan sea otters

    USGS Publications Warehouse

    Hanni, K.D.; Mazet, J.A.K.; Gulland, F.M.D.; Estes, James; Staedler, M.; Murray, M.J.; Miller, M.; Jessup, David A.

    2003-01-01

    The southern sea otter (Enhydra lutris nereis) population in California (USA) and the Alaskan sea otter (E. lutris kenyoni) population in the Aleutian Islands (USA) chain have recently declined. In order to evaluate disease as a contributing factor to the declines, health assessments of these two sea otter populations were conducted by evaluating hematologic and/or serum biochemical values and exposure to six marine and terrestrial pathogens using blood collected during ongoing studies from 1995 through 2000. Samples from 72 free-ranging Alaskan, 78 free-ranging southern, and (for pathogen exposure only) 41 debilitated southern sea otters in rehabilitation facilities were evaluated and compared to investigate regional differences. Serum chemistry and hematology values did not indicate a specific disease process as a cause for the declines. Statistically significant differences were found between free-ranging adult southern and Alaskan population mean serum levels of creatinine kinase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, calcium, cholesterol, creatinine, glucose, phosphorous, total bilirubin, blood urea nitrogen, and sodium. These were likely due to varying parasite loads, contaminant exposures, and physiologic or nutrition statuses. No free-ranging sea otters had signs of disease at capture, and prevalences of exposure to calicivirus, Brucella spp., and Leptospira spp. were low. The high prevalence (35%) of antibodies to Toxoplasma gondii in free-ranging southern sea otters, lack of antibodies to this parasite in Alaskan sea otters, and the pathogen's propensity to cause mortality in southern sea otters suggests that this parasite may be important to sea otter population dynamics in California but not in Alaska. The evidence for exposure to pathogens of public health importance (e.g., Leptospira spp., T. gondii) in the southern sea otter population, and the nai??vete?? of both populations to other pathogens (e

  13. Characteristics and petrogenesis of Alaskan-type ultramafic-gabbro intrusions, southeastern Alaska

    SciTech Connect

    Loney, R.A. ); Himmelberg, G.R. Univ. of Missouri, Columbia, MO )

    1993-04-01

    Alaskan-type ultramafic-gabbro intrusions occur along a belt that extends from Duke Island to Klukwan in southeastern Alaska and fall into two age groups, 400 to 440 Ma and 100 to 110 Ma. Most of the smaller bodies are magnetite-bearing hornblende clinopyroxenite; the larger ones consist of dunite, wehrlite, olivine clinopyroxenite, with some gabbro, in addition to hornblende clinopyroxenite and hornblendite. Textural, mineralogical, and chemical characteristics of the Alaskan-type ultramafic bodies indicate that they originated by fractional crystallization of a basaltic magma and accumulation in a crustal magma chamber. The Al[sub 2]O[sub 3] content of clinopyroxene shows a marked enrichment with differentiation, suggesting crystallization from progressively more hydrous melts like those characteristics of arc magmas. REE abundance levels and patterns are markedly similar for given rock units in all the bodies studied suggesting that all the bodies were derived by differentiation of closely similar parent magmas under near identical conditions. The exact composition of the primary melt is uncertain but the authors' preferred interpretation is that the parental magma of most Alaskan-type bodies was a subalkaline hydrous basalt. The striking similarity between the REE abundance levels and patterns of the Alaskan-type clinopyroxenites and gabbros, and the clinopyroxenite xenoliths and plutonic gabbros associated with Aleutian Island Arc volcanism, further suggests that the primary magma was probably a hydrous olivine basalt similar to the primary magma proposed for the Aleutian arc lavas. The mineral chemistry and phase equilibria of the ultramafic bodies suggest that they crystallized in magma chambers at depths greater than about 9 km. Except for the Duke Island body, which has sedimentary structures and shows evidence of ubiquitous current activity, most of the other bodies appear to have accumulated under static conditions.

  14. Projected Duration of the Sea-Ice-Free Season in the Future Alaskan Arctic

    NASA Astrophysics Data System (ADS)

    Wang, M.; Overland, J. E.

    2014-12-01

    The change in the Arctic climate is fast and broad. Among many changes that have been observed, the reduction of sea ice coverage has been one of the most significant factors. Continued reduction in sea ice cover will probably result in longer open water duration, which is important for the shipping industry, marine mammals as well as other component of the local ecosystem. In this study we are to assess future sea ice conditions, particularly the length of open water duration in the Alaskan Arctic over the next few decades using the latest coupled climate models (CMIP5). The Alaskan Arctic, including the Chukchi and the Beaufort Sea, has been a major region of summer sea ice retreat since 2007. Based on the mean of 12 climate models, for the region north of the Bering Strait (70° N), future open-water duration may extend from a current 3-4 months to around five months by 2050. It is about one month shorter along the same latitude over the Beaufort Sea. The difference in the length of ice-free season between the north and the south will remain, but will be smaller in the 21st century compared with current condition. Open-water duration in the Alaskan Arctic expands quickly in these models over the next decades, in contrast to model under-predictions of sea ice loss for the summer minimum over the Arctic wide domain. Uncertainty is generally ±one month estimated from the range of model results. Continued increases in open-water duration over the next two decades will impact regional economic access and potentially alter ecosystems, yet we need to keep in mind that from December through May most of the northern Alaskan Arctic will remain sea ice covered into the second half of the century.

  15. Juvenile laryngeal paralysis in three Siberian husky x Alaskan malamute puppies.

    PubMed

    Polizopoulou, Z S; Koutinas, A F; Papadopoulos, G C; Saridomichelakis, M N

    2003-11-15

    Three three-month-old Siberian husky x Alaskan malamute crossbreds had suffered episodic inspiratory dyspnoea and stridor for four to eight weeks and their endurance had decreased. In two of them bilateral, and in the other unilateral, laryngeal paralysis was diagnosed by laryngoscopy. In the nucleus ambiguus of the dogs there was a depletion of motor neurons, neuronal degeneration and mild gliosis, but there were no lesions in the root and peripheral segments of the recurrent laryngeal nerves.

  16. Does surface roughness amplify wetting?

    SciTech Connect

    Malijevský, Alexandr

    2014-11-14

    Any solid surface is intrinsically rough on the microscopic scale. In this paper, we study the effect of this roughness on the wetting properties of hydrophilic substrates. Macroscopic arguments, such as those leading to the well-known Wenzel's law, predict that surface roughness should amplify the wetting properties of such adsorbents. We use a fundamental measure density functional theory to demonstrate the opposite effect from roughness for microscopically corrugated surfaces, i.e., wetting is hindered. Based on three independent analyses we show that microscopic surface corrugation increases the wetting temperature or even makes the surface hydrophobic. Since for macroscopically corrugated surfaces the solid texture does indeed amplify wetting there must exist a crossover between two length-scale regimes that are distinguished by opposite response on surface roughening. This demonstrates how deceptive can be efforts to extend the thermodynamical laws beyond their macroscopic territory.

  17. Viability of the Alaskan breeding population of Steller’s eiders

    USGS Publications Warehouse

    Dunham, Kylee; Grand, James B.

    2016-10-11

    The U.S. Fish and Wildlife Service is tasked with setting objective and measurable criteria for delisting species or populations listed under the Endangered Species Act. Determining the acceptable threshold for extinction risk for any species or population is a challenging task, particularly when facing marked uncertainty. The Alaskan breeding population of Steller’s eiders (Polysticta stelleri) was listed as threatened under the Endangered Species Act in 1997 because of a perceived decline in abundance throughout their nesting range and geographic isolation from the Russian breeding population. Previous genetic studies and modeling efforts, however, suggest that there may be dispersal from the Russian breeding population. Additionally, evidence exists of population level nonbreeding events. Research was conducted to estimate population viability of the Alaskan breeding population of Steller’s eiders, using both an open and closed model of population process for this threatened population. Projections under a closed population model suggest this population has a 100 percent probability of extinction within 42 years. Projections under an open population model suggest that with immigration there is no probability of permanent extinction. Because of random immigration process and nonbreeding behavior, however, it is likely that this population will continue to be present in low and highly variable numbers on the breeding grounds in Alaska. Monitoring the winter population, which includes both Russian and Alaskan breeding birds, may offer a more comprehensive indication of population viability.

  18. Task 27 -- Alaskan low-rank coal-water fuel demonstration project

    SciTech Connect

    1995-10-01

    Development of coal-water-fuel (CWF) technology has to-date been predicated on the use of high-rank bituminous coal only, and until now the high inherent moisture content of low-rank coal has precluded its use for CWF production. The unique feature of the Alaskan project is the integration of hot-water-drying (HWD) into CWF technology as a beneficiation process. Hot-water-drying is an EERC developed technology unavailable to the competition that allows the range of CWF feedstock to be extended to low-rank coals. The primary objective of the Alaskan Project, is to promote interest in the CWF marketplace by demonstrating the commercial viability of low-rank coal-water-fuel (LRCWF). While commercialization plans cannot be finalized until the implementation and results of the Alaskan LRCWF Project are known and evaluated, this report has been prepared to specifically address issues concerning business objectives for the project, and outline a market development plan for meeting those objectives.

  19. Long-term climate patterns in Alaskan surface temperature and precipitation and their biological consequences

    USGS Publications Warehouse

    Simpson, James J.; Hufford, Gary L.; Fleming, Michael D.; Berg, Jared S.; Ashton, J.B.

    2002-01-01

    Mean monthly climate maps of Alaskan surface temperature and precipitation produced by the parameter-elevation regression on independent slopes model (PRISM) were analyzed. Alaska is divided into interior and coastal zones with consistent but different climatic variability separated by a transition region; it has maximum interannual variability but low long-term mean variability. Pacific decadal oscillation (PDO)- and El Nin??o southern oscillation (ENSO)-type events influence Alaska surface temperatures weakly (1-2 ??C) statewide. PDO has a stronger influence than ENSO on precipitation but its influence is largely localized to coastal central Alaska. The strongest influence of Arctic oscillation (AO) occurs in northern and interior Alaskan precipitation. Four major ecosystems are defined. A major eco-transition zone occurs between the interior boreal forest and the coastal rainforest. Variability in insolation, surface temperature, precipitation, continentality, and seasonal changes in storm track direction explain the mapped ecosystems. Lack of westward expansion of the interior boreal forest into the western shrub tundra is influenced by the coastal marine boundary layer (enhanced cloud cover, reduced insolation, cooler surface and soil temperatures). In this context, the marine boundary layer acts in an analogous fashion to the orographic features which form the natural boundaries of other Alaskan ecosystems. Variability in precipitation may play a secondary role.

  20. Wet Mars, Dry Mars

    NASA Astrophysics Data System (ADS)

    Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Yan, D.; Fricke, K. W.; Thrall, L.

    2012-12-01

    The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This poster highlights the third in a series of presentations that target school-age audiences with the overall goal of helping the audience visualize planetary magnetic field and understand how they can impact the climatic evolution of a planet. Our first presentation, "Goldilocks and the Three Planets," targeted to elementary school age audiences, focuses on the differences in the atmospheres of Venus, Earth, and Mars and the causes of the differences. The second presentation, "Lost on Mars (and Venus)," geared toward a middle school age audience, highlights the differences in the magnetic fields of these planets and what we can learn from these differences. Finally, in the third presentation, "Wet Mars, Dry Mars," targeted to high school age audiences and the focus of this poster, the emphasis is on the long term climatic affects of the presence or absence of a magnetic field using the contrasts between Earth and Mars. These presentations are given using visually engaging spherical displays in conjunction with hands-on activities and scientifically accurate 3D models of planetary magnetic fields. We will summarize the content of our presentations, discuss our lessons learned from evaluations, and show (pictures of) our hands-on activities and 3D models.

  1. Wet Mars, Dry Mars

    NASA Astrophysics Data System (ADS)

    Fillingim, Matthew; Brain, D.; Peticolas, L.; Yan, D.; Fricke, K.; Thrall, L.

    2012-10-01

    The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This poster highlights the third in a series of presentations that target school-age audiences with the overall goal of helping the audience visualize planetary magnetic field and understand how they can impact the climatic evolution of a planet. Our first presentation, "Goldilocks and the Three Planets," targeted to elementary school age audiences, focuses on the differences in the atmospheres of Venus, Earth, and Mars and the causes of the differences. The second presentation, "Lost on Mars (and Venus)," geared toward a middle school age audience, highlights the differences in the magnetic fields of these planets and what we can learn from these differences. Finally, in the third presentation, "Wet Mars, Dry Mars," targeted to high school age audiences and the focus of this poster, the emphasis is on the long term climatic affects of the presence or absence of a magnetic field using the contrasts between Earth and Mars. These presentations are given using visually engaging spherical displays in conjunction with hands-on activities and scientifically accurate 3D models of planetary magnetic fields. We will summarize the content of our presentations, discuss our "lessons learned" from formative evaluation, and show (pictures of) our hands-on activities and 3D models.

  2. WET AND DRY SCRUBBERS FOR EMISSION CONTROL

    EPA Science Inventory

    Generally speaking, absorption equipment includes two major categories: Wet adsorption scrubbers (or wet scrubbers); Dry absorption scrubbers (or dry scrubbers).
    Wet scrubbers: As the name implies, wet scrubbers (also known as wet collectors) are devices which use a liquid fo...

  3. A native sedge, Carex nudata, as facilitator of restoration goals: effects on channel morphology and planform in the Middle Fork John Day River

    NASA Astrophysics Data System (ADS)

    Goslin, M.; McDowell, P. F.

    2015-12-01

    In the Middle Fork of the John Day River, the native riparian sedge, Carex nudata, has exploded across the landscape following the removal of cattle grazing in the late 1990s. C. nudata now forms fringes along the edges of the low flow channel and grows as islands within the river. C. nudata appears to be altering channel morphology and planform in ways that may facilitate key restoration goals. I have employed multiple methods to investigate changes in channel morphology and planform in association with C. nudata: aerial imagery analysis, repeated topographic surveys, and erosion pins in cut banks with C. nudata fringes. Preliminary results suggest that C. nudata stabilizes the edges of the low flow channel, but cut banks behind C. nudata fringes continue to erode such that the bankflow width and channel boundaries continue to move. Aerial imagery analysis indicates that current C. nudata islands are often the result of C. nudata fringes becoming "detached" from banks rather than from initial establishment of plants in midchannel positions. Topographic surveys suggest scouring upstream of C. nudata islands and along the edges of C. nudata fringes. We propose a conceptual model in which multiple alternative pathways of river development may be possible after the establishment of C. nudata, depending on the antecedent conditions where it becomes established (e.g. bank composition, river curvature). Alternative pathways include: 1) bank stabilization, channel narrowing and deepening; 2) formation of a compound channel with a side channel that is activated at high flows; 3) the formation of islands within the channel. The potential for multiple pathways of development after C. nudata establishment may lead to complex patterns of river morphology and planform consistent with habitat complexity goals of river restoration.

  4. A regional approach to plant DNA barcoding provides high species resolution of sedges (Carex and Kobresia, Cyperaceae) in the Canadian Arctic Archipelago.

    PubMed

    Clerc-Blain, Jessica L E; Starr, Julian R; Bull, Roger D; Saarela, Jeffery M

    2010-01-01

    Previous research on barcoding sedges (Carex) suggested that basic searches within a global barcoding database would probably not resolve more than 60% of the world's some 2000 species. In this study, we take an alternative approach and explore the performance of plant DNA barcoding in the Carex lineage from an explicitly regional perspective. We characterize the utility of a subset of the proposed protein-coding and noncoding plastid barcoding regions (matK, rpoB, rpoC1, rbcL, atpF-atpH, psbK-psbI) for distinguishing species of Carex and Kobresia in the Canadian Arctic Archipelago, a clearly defined eco-geographical region representing 1% of the Earth's landmass. Our results show that matK resolves the greatest number of species of any single-locus (95%), and when combined in a two-locus barcode, it provides 100% species resolution in all but one combination (matK + atpFH) during unweighted pair-group method with arithmetic mean averages (UPGMA) analyses. Noncoding regions were equally or more variable than matK, but as single markers they resolve substantially fewer taxa than matK alone. When difficulties with sequencing and alignment due to microstructural variation in noncoding regions are also considered, our results support other studies in suggesting that protein-coding regions are more practical as barcoding markers. Plastid DNA barcodes are an effective identification tool for species of Carex and Kobresia in the Canadian Arctic Archipelago, a region where the number of co-existing closely related species is limited. We suggest that if a regional approach to plant DNA barcoding was applied on a global scale, it could provide a solution to the generally poor species resolution seen in previous barcoding studies.

  5. Forced wetting and hydrodynamic assist

    NASA Astrophysics Data System (ADS)

    Blake, Terence D.; Fernandez-Toledano, Juan-Carlos; Doyen, Guillaume; De Coninck, Joël

    2015-11-01

    Wetting is a prerequisite for coating a uniform layer of liquid onto a solid. Wetting failure and air entrainment set the ultimate limit to coating speed. It is well known in the coating art that this limit can be postponed by manipulating the coating flow to generate what has been termed "hydrodynamic assist," but the underlying mechanism is unclear. Experiments have shown that the conditions that postpone air entrainment also reduce the apparent dynamic contact angle, suggesting a direct link, but how the flow might affect the contact angle remains to be established. Here, we use molecular dynamics to compare the outcome of steady forced wetting with previous results for the spontaneous spreading of liquid drops and apply the molecular-kinetic theory of dynamic wetting to rationalize our findings and place them on a quantitative footing. The forced wetting simulations reveal significant slip at the solid-liquid interface and details of the flow immediately adjacent to the moving contact line. Our results confirm that the local, microscopic contact angle is dependent not simply only on the velocity of wetting but also on the nature of the flow that drives it. In particular, they support an earlier suggestion that during forced wetting, an intense shear stress in the vicinity of the contact line can assist surface tension forces in promoting dynamic wetting, thus reducing the velocity-dependence of the contact angle. Hydrodynamic assist then appears as a natural consequence of wetting that emerges when the contact line is driven by a strong and highly confined flow. Our theoretical approach also provides a self-consistent model of molecular slip at the solid-liquid interface that enables its magnitude to be estimated from dynamic contact angle measurements. In addition, the model predicts how hydrodynamic assist and slip may be influenced by liquid viscosity and solid-liquid interactions.

  6. 33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force....

  7. 33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force....

  8. 33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force....

  9. 33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force....

  10. 33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force....

  11. WET BEAVER ROADLESS AREA, ARIZONA.

    USGS Publications Warehouse

    Ulrich, George E.; Bielski, Alan M.

    1984-01-01

    On the basis of field studies there is little promise for the occurrence of mineral or energy resources in the Wet Beaver Roadless Area, Arizona. No significant concentrations of metals were indicated by geochemical sampling or aeromagnetic data within the area. Basaltic cinders and sandstone have been quarried for construction materials near the area but are readily available and more accessible outside the precipitous canyons of Wet Beaver Creek and its tributaries.

  12. Free radical scavenging, α-glucosidase inhibitory and anti-inflammatory constituents from Indian sedges, Cyperus scariosus R.Br and Cyperus rotundus L.

    PubMed Central

    Kakarla, Lavanya; Katragadda, Suresh Babu; Tiwari, Ashok K; Kotamraju, K Srigiridhar; Madhusudana, K; Kumar, D Anand; Botlagunta, Mahendran

    2016-01-01

    Background: Cyperus scariosus R. Br and Cyperus rotundus L are widely used in ayurvedic preparation for the treatment of diabetes and other diseases. The early literature, so far, does not indicate the presence of any bioactive principle isolated from these plants. Objective: To identify free radical scavenging, anti-diabetic and anti- inflammatory principles from these two species. Materials and Methods: The bioassay guided fractionation and isolation of active constituents was done by chromatographic techniques. They also evaluated their anti-oxidant activity by DPPH and ABTS. The anti-diabetic activity was screened by α- glucosidase and α- amylase assays. Also, the further evaluation of in vitro anti-inflammatory activity using THP-1 monocytic cells and in vivo anti- inflammatory activity, was confirmed by carrageenan induced rat paw edema as model. Results: The activity guided isolation led to isolation of twelve compounds Which are: Stigmasterol[1], β- sitosterol[2], Lupeol[3], Gallic acid[4], Quercetin[5], β- amyrin[6], Oleanolic acid[7], β- amyrin acetate[8], 4- hydroxyl butyl cinnamate[9], 4- hydroxyl cinnamic acid[10], Caffeic acid,[11] and Kaempferol[12] respectively. Among the isolates, the compounds 4 and 5 displayed potent radical scavenging activity with an IC50 values of 0.43 and 0.067 ΅g/ml. The compounds 4, 5 and 10 showed significant anti-diabetic activities. while lupeol[3] showed potent IL-1 β activity inhibition in THP-1 monocytic cells and also displayed significant (p<0.0025) in vivo anti-inflammatory activity. Conclusion: Inbrief, we isolated twelve compounds from both the species. Collectively, our results suggested that aromatic compounds showed good anti-oxidant and anti-diabetic activities. SUMMARY The study investigates the free radical scavenging, α-glucosidase inhibitory and anti-inflammatory effects of constituents isolated from Indian sedges viz. C. scariosus and C. rotundus. The results indicated that phenolic compounds

  13. Earthquake triggering at alaskan volcanoes following the 3 November 2002 denali fault earthquake

    USGS Publications Warehouse

    Moran, S.C.; Power, J.A.; Stihler, S.D.; Sanchez, J.J.; Caplan-Auerbach, J.

    2004-01-01

    The 3 November 2002 Mw 7.9 Denali fault earthquake provided an excellent opportunity to investigate triggered earthquakes at Alaskan volcanoes. The Alaska Volcano Observatory operates short-period seismic networks on 24 historically active volcanoes in Alaska, 247-2159 km distant from the mainshock epicenter. We searched for evidence of triggered seismicity by examining the unfiltered waveforms for all stations in each volcano network for ???1 hr after the Mw 7.9 arrival time at each network and for significant increases in located earthquakes in the hours after the mainshock. We found compelling evidence for triggering only at the Katmai volcanic cluster (KVC, 720-755 km southwest of the epicenter), where small earthquakes with distinct P and 5 arrivals appeared within the mainshock coda at one station and a small increase in located earthquakes occurred for several hours after the mainshock. Peak dynamic stresses of ???0.1 MPa at Augustine Volcano (560 km southwest of the epicenter) are significantly lower than those recorded in Yellowstone and Utah (>3000 km southeast of the epicenter), suggesting that strong directivity effects were at least partly responsible for the lack of triggering at Alaskan volcanoes. We describe other incidents of earthquake-induced triggering in the KVC, and outline a qualitative magnitude/distance-dependent triggering threshold. We argue that triggering results from the perturbation of magmatic-hydrothermal systems in the KVC and suggest that the comparative lack of triggering at other Alaskan volcanoes could be a result of differences in the nature of magmatic-hydrothermal systems.

  14. The Apparent Periodicity of Felt Reports in the Alaskan Earthquake Record

    NASA Astrophysics Data System (ADS)

    Hafner, L. A.; McNutt, S. R.

    2004-12-01

    Felt reports for Alaskan earthquakes were found to be non-uniformly distributed throughout the year. With a predominantly tourist economy, the Alaskan population nearly triples in the summer months, possibly affecting the reporting of earthquakes in the historical record. Using published felt reports from the National Earthquake Information Center and the Alaska Earthquake Information Center, the percentage of events felt each month in central mainland Alaska were tabulated and compared between the summer and winter seasons. Earthquakes were selected from January 1, 1990 to October 31, 2002, from latitudes 58 to 70 degrees N and longitudes 140 to 160 degrees W, and depths 0 to 200 km. 408 events were felt out of a total of 695 that occurred. A number of parameters, including time of day, latitude, longitude, and magnitude, were additionally compared to specify possible limiting factors within each season. While a strong seasonal effect was not found in magnitude 4.0 ML events and greater, the months of May and June were consistently found to have the highest percentage of felt events with a steep drop occurring in the month of July. We ascribe this effect to the summer melting of the top layer of frozen ground to a depth of about 1.5 meters. Additionally, smaller events from magnitude 1.0 to 4.0 ML were also examined. 396 events were felt out of a total of 7,451 that occurred. We found that small earthquakes were felt, with a significant difference, more readily during summer months than in winter. This is likely an effect of the higher summer population of tourists and greater distribution of open businesses. Together these observations suggest that the historical Alaskan earthquake record is likely biased in favor of more frequent reporting of events occurring in summer months as opposed to winter.

  15. Implications of lifting the ban on the export of Alaskan crude oil: Price and trade impacts

    SciTech Connect

    Not Available

    1990-06-26

    This study addresses the issue of the ban on exports of Alaskan crude oil. At present almost all crude oil production from Alaska must be sold in the United States, i.e., it may not be exported. This study examines the impact, mainly on the West Coast, of eliminating this export restraint. The study concentrates on two time periods. These are 1988, the most recent year for which complete data are available, and 1995, a year in which Alaskan production is projected to be substantially less than at present. This is the Energy Information Administration's (EIA's) second report on this subject. The first was released earlier in 1990. They differ principally in the years for which results are presented and in the models used to generate quantitative results. The first report was limited to 1988. The quantitative results for that year were based on use of a single region model and therefore did not take into account petroleum interactions among all areas of the world. Because of this limitation, quantitative results were limited to Alaskan crude oil prices. All other price and trade flow results were qualitative. In contrast, the present report covers both 1988 and 1995. The quantitative results are generated with use of a more comprehensive model, one which does take into account petroleum interactions among all areas of the world. The model-generated results cover both crude and product prices as well as petroleum trade flows. The quantitative results in the present report therefore supersede those in the first, although both sets are generally consistent.

  16. Alaskan marine mammal tissue archival project: a project description including collection protocols

    SciTech Connect

    Becker, P.R.; Wise, S.A.; Koster, B.J.; Zeisler, R.

    1988-03-01

    The Alaskan Marine Mammal Tissue Archival Project was initiated in 1987. Although the emphasis is on the collection of tissues for analysis of contaminants that may be associated with the petroleum industry, the development of an archive of marine mammal tissues collected and stored using carefully controlled procedures provides an important resource addressing questions concerning the transport of elements and compounds (contaminants and non-contaminants) throughout the polar ecosystem. The document provides the basic information on Project objectives and management, justification for the species, tissues, and contaminants of interest, and specific instructions for collecting, handling, and storing samples.

  17. First Alaskan records and a significant northern range extension for two species of Diplura (Diplura, Campodeidae)

    PubMed Central

    Sikes, Derek S.; Allen, Robert T.

    2016-01-01

    Abstract Species in the class Diplura are recorded from Alaska for the first time. Two species, Tricampa rileyi Silvestri from Dall and Prince of Wales Islands in the Alexander Archipelago of Southeast Alaska and Metriocampa allocerca Conde & Geeraert from near Quartz Lake, southeast of Fairbanks, both in the family Campodeidae, are documented based on recently collected specimens deposited in the University of Alaska Museum Insect Collection. A brief review of the history of the documentation of the Alaskan soil microarthropod fauna is provided, as well as discussion of possible glacial refugia. PMID:27047242

  18. Anti-infective Discorhabdins from a Deep-Water Alaskan Sponge of the Genus Latrunculia†

    PubMed Central

    Na, MinKyun; Ding, Yuanqing; Wang, Bin; Tekwani, Babu L.; Schinazi, Raymond F.; Franzblau, Scott; Kelly, Michelle; Stone, Robert; Li, Xing-Cong; Ferreira, Daneel; Hamann, Mark T.

    2016-01-01

    Bioassay- and LC-MS-guided fractionation of a methanol extract from a new deep-water Alaskan sponge species of the genus Latrunculia resulted in the isolation of two new brominated pyrroloiminoquinones, dihydrodiscorhabdin B (1) and discorhabdin Y (2), along with six known pyrroloiminoquinone alkaloids, discorhabdins A (3), C (4), E (5), and L (6), dihydrodiscorhabdin C (7), and the benzene derivative 8. Compounds 3, 4, and 7 exhibited anti-HCV activity, antimalarial activity, and selective antimicrobial activity. Although compounds 3 and 7 displayed potent and selective in vitro antiprotozoal activity, Plasmodium berghei-infected mice did not respond to these metabolites due to their toxicity in vivo. PMID:20337497

  19. Enhanced removal of Exxon Valdez spilled oil Alaskan gravel by a microbial surfactant

    SciTech Connect

    Harvey, S.; Elashvili, I.; Valdes, J.J.; Kamely, D.; Chakrabarty, A.M. )

    1990-03-01

    Remediation efforts for the oil spill from the Exxon Valdez tanker in Alaska have focused on the use of pressurized water at high temperature to remove oil from the beaches. We have tested a biological surfactant from Pseudomonas aeruginosa for its ability to remove oil from contaminated Alaskan gravel samples under various conditions, including concentration of the surfactant, time of contact, temperature of the wash, and presence or absence of xanthan gum. The results demonstrate the ability of the microbial surfactant to release oil to a significantly greater extent (2 to 3 times) than water alone, particularly at temperatures of 30{degree}C and above.

  20. Enhanced removal of Exxon Valdez spilled oil from Alaskan gravel by a microbial surfactant.

    PubMed

    Harvey, S; Elashvili, I; Valdes, J J; Kamely, D; Chakrabarty, A M

    1990-03-01

    Remediation efforts for the oil spill from the Exxon Valdez tanker in Alaska have focused on the use of pressurized water at high temperature to remove oil from the beaches. We have tested a biological surfactant from Pseudomonas aeruginosa for its ability to remove oil from contaminated Alaskan gravel samples under various conditions, including concentration of the surfactant, time of contact, temperature of the wash, and presence or absence of xanthan gum. The results demonstrate the ability of the microbial surfactant to release oil to a significantly greater extent (2 to 3 times) than water alone, particularly at temperatures of 30 degrees C and above. PMID:1367420

  1. Enhanced removal of Exxon Valdez spilled oil from Alaskan gravel by a microbial surfactant.

    PubMed

    Harvey, S; Elashvili, I; Valdes, J J; Kamely, D; Chakrabarty, A M

    1990-03-01

    Remediation efforts for the oil spill from the Exxon Valdez tanker in Alaska have focused on the use of pressurized water at high temperature to remove oil from the beaches. We have tested a biological surfactant from Pseudomonas aeruginosa for its ability to remove oil from contaminated Alaskan gravel samples under various conditions, including concentration of the surfactant, time of contact, temperature of the wash, and presence or absence of xanthan gum. The results demonstrate the ability of the microbial surfactant to release oil to a significantly greater extent (2 to 3 times) than water alone, particularly at temperatures of 30 degrees C and above.

  2. Paleoclimatic forcing of magnetic susceptibility variations in Alaskan loess during the late Quaternary

    SciTech Connect

    Beget, J.E.; Stone, D.B.; Hawkins, D.B. )

    1990-01-01

    Visual matches and statistical tests suggest correlations between marine isotope curves, retrodictive solar insolation at lat 65{degree}N, and magnetic susceptibility profiles through late Quaternary age Alaskan loess sections. The susceptibility changes largely appear to reflect variability in magnetite content due to climatically controlled changes in wind intensity and competence. Magnetic susceptibility profiles through massive loess can provide stratigraphic context for intercalated paleosols and tephras. A prominent paleosol correlated with marine isotope stage 5 occurs several metres above the Old Crow ash in loess sections, indicating that this important tephra is older than suggested by thermoluminescence dates, and may have been deposited ca. 215 {plus minus}25 ka.

  3. The Changing Alaskan Experience—Health Care Services and Cultural Identity

    PubMed Central

    Dixon, Mim; Myers, Wayne W.; Book, Patricia A.; Nice, Philip O.

    1983-01-01

    Before Western contact, Alaskan Native populations were self-sufficient in their health practices. Slowly, the Native health care system was replaced by a Western one which was highly effective in treating infectious diseases. As infectious diseases were brought under control by the Indian Health Service, the emergent leading health problems were related to violence, attributed in part to cultural disintegration. New types of Native health providers and new Native-controlled institutions evolved to provide culturally appropriate health and mental health services and to promote a stronger cultural identity. PMID:6666110

  4. Surface structure determines dynamic wetting

    NASA Astrophysics Data System (ADS)

    Shiomi, Junichiro; Wang, Jiayu; Do-Quang, Minh; Cannon, James; Yue, Feng; Suzuki, Yuji; Amberg, Gustav

    2014-11-01

    Dynamic wetting, the spontaneous spreading process after droplet contacts a solid surface, is important in various engineering processes, such as in printing, coating, and lubrication. In the recent years, experiments and numerical simulations have greatly progressed the understanding in the dynamic wetting particularly on ``flat'' substrates. To gain further insight into the governing physics of the dynamic wetting, we perform droplet-wetting experiments on microstructured surfaces, just a few micrometers in size, with complementary numerical simulations, and investigate the dependence of the spreading rate on the microstructure geometries and fluid properties. We reveal that the influence of microstructures can be quantified in terms of a line friction coefficient for the energy dissipation rate at the contact line, and that this can be described in a simple formula in terms of the geometrical parameters of the roughness and the line-friction coefficient of the planar surface. The systematic study is also of practical importance since structures and roughness are omnipresent and their influence on spreading rate would give us additional degrees of freedom to control the dynamic wetting. This work was financially supported in part by, the Japan Society for the Promotion of Science (J.W., J.C., and J.S) and Swedish Governmental Agency for Innovation Systems (M.D.-Q. and G.A.).

  5. Do peat amendments to oil sands wet sediments affect Carex aquatilis biomass for reclamation success?

    PubMed

    Roy, Marie-Claude; Mollard, Federico P O; Foote, A Lee

    2014-06-15

    The oil sands industries of Alberta (Canada) have reclamation objectives to return the mined landscape to equivalent pre-disturbance land capability. Industrial operators are charged with reclaiming a vast landscape of newly exposed sediments on saline-sodic marine-shales sediments. Incorporated in these sediments are by-products resulting from bitumen extraction (consolidated tailings (CT), tailings-sand (TS), and oil sands processed water (OSPW)). A sedge community dominated by Carex aquatilis was identified as a desirable and representative late-succession community for wet-meadow zones of oil sands-created marshes. However, the physical and chemical conditions, including high salinity and low nutrient content of CT and TS sediments suppress plant growth and performance. We experimentally tested the response of C. aquatilis to amendments with peat-mineral-mix (PM) on oil sand sediments (CT and TS). In a two factorial design experiment, we also tested the effects of OSPW on C. aquatilis. We assessed survival, below- and aboveground biomass, and physiology (chlorophyll a fluorescence). We demonstrated that PM amendments to oil sands sediments significantly increased C. aquatilis survival as well as below and aboveground biomass. The use of OSPW significantly reduced C. aquatilis belowground biomass and affected its physiological performance. Due to its tolerance and performance, we verified that C. aquatilis was a good candidate for use in reclaiming the wet-meadow zones of oil sands-created marshes. Ultimately, amending CT and TS with PM expedited the reclamation of the wetland to a C. aquatilis-community which was similar in gross structure to undisturbed wetlands of the region.

  6. Surface structure determines dynamic wetting

    PubMed Central

    Wang, Jiayu; Do-Quang, Minh; Cannon, James J.; Yue, Feng; Suzuki, Yuji; Amberg, Gustav; Shiomi, Junichiro

    2015-01-01

    Liquid wetting of a surface is omnipresent in nature and the advance of micro-fabrication and assembly techniques in recent years offers increasing ability to control this phenomenon. Here, we identify how surface roughness influences the initial dynamic spreading of a partially wetting droplet by studying the spreading on a solid substrate patterned with microstructures just a few micrometers in size. We reveal that the roughness influence can be quantified in terms of a line friction coefficient for the energy dissipation rate at the contact line, and that this can be described in a simple formula in terms of the geometrical parameters of the roughness and the line-friction coefficient of the planar surface. We further identify a criterion to predict if the spreading will be controlled by this surface roughness or by liquid inertia. Our results point to the possibility of selectively controlling the wetting behavior by engineering the surface structure. PMID:25683872

  7. Squeezing wetting and nonwetting liquids.

    PubMed

    Samoilov, V N; Persson, B N J

    2004-01-22

    We present molecular-dynamics results for the squeezing of octane (C8H18) between two approaching solid elastic walls with different wetting properties. The interaction energy between the octane bead units and the solid walls is varied from a very small value (1 meV), corresponding to a nonwetting surface with a very large contact angle (nearly 180 degrees), to a high value (18.6 meV) corresponding to complete wetting. When at least one of the solid walls is wetted by octane we observe well defined molecular layers develop in the lubricant film when the thickness of the film is of the order of a few atomic diameters. An external squeezing-pressure induces discontinuous, thermally activated changes in the number n of lubricant layers (n-->n-1 layering transitions). With increasing interaction energy between the octane bead units and the solid walls, the transitions from n to n-1 layers occur at higher average pressure. This results from the increasing activation barrier to nucleate the squeeze-out with increasing lubricant-wall binding energy (per unit surface area) in the contact zone. Thus, strongly wetting lubricant fluids are better boundary lubricants than the less wetting ones, and this should result in less wear. We analyze in detail the effect of capillary bridge formation (in the wetting case) and droplets formation (in the nonwetting case) on the forces exerted by the lubricant on the walls. For the latter case small liquid droplets may be trapped at the interface, resulting in a repulsive force between the walls during squeezing, until the solid walls come into direct contact, where the wall-wall interaction may be initially attractive. This effect is made use of in some practical applications, and we give one illustration involving conditioners for hair care application. PMID:15268334

  8. Squeezing wetting and nonwetting liquids

    NASA Astrophysics Data System (ADS)

    Samoilov, V. N.; Persson, B. N. J.

    2004-01-01

    We present molecular-dynamics results for the squeezing of octane (C8H18) between two approaching solid elastic walls with different wetting properties. The interaction energy between the octane bead units and the solid walls is varied from a very small value (1 meV), corresponding to a nonwetting surface with a very large contact angle (nearly 180 degrees), to a high value (18.6 meV) corresponding to complete wetting. When at least one of the solid walls is wetted by octane we observe well defined molecular layers develop in the lubricant film when the thickness of the film is of the order of a few atomic diameters. An external squeezing-pressure induces discontinuous, thermally activated changes in the number n of lubricant layers (n→n-1 layering transitions). With increasing interaction energy between the octane bead units and the solid walls, the transitions from n to n-1 layers occur at higher average pressure. This results from the increasing activation barrier to nucleate the squeeze-out with increasing lubricant-wall binding energy (per unit surface area) in the contact zone. Thus, strongly wetting lubricant fluids are better boundary lubricants than the less wetting ones, and this should result in less wear. We analyze in detail the effect of capillary bridge formation (in the wetting case) and droplets formation (in the nonwetting case) on the forces exerted by the lubricant on the walls. For the latter case small liquid droplets may be trapped at the interface, resulting in a repulsive force between the walls during squeezing, until the solid walls come into direct contact, where the wall-wall interaction may be initially attractive. This effect is made use of in some practical applications, and we give one illustration involving conditioners for hair care application.

  9. Anthropogenic and natural radionuclides in caribou and muskoxen in the western Alaskan Arctic and marine fish in the Aleutian Islands in the first half of 2000s.

    PubMed

    Hong, Gi Hoon; Baskaran, Mark; Molaroni, Shannon Marie; Lee, Hyun-Mi; Burger, Joanna

    2011-09-01

    A number of caribou and muskoxen samples from the western Alaskan Arctic and fish samples from the Aleutian Islands were collected between 1998 and 2006 and analyzed for anthropogenic ((90)Sr and (137)Cs) and natural radionculides ((40)K, (210)Pb and (226)Ra), as part of the radiological assessment for the regional subsistence hunting communities in the first half of 2000s. We examined the relationship between the activities of these nuclides with the size of the fish. In caribou samples, concentration of (90)Sr in muscle was below the detection limit of 0.14 Bq kg(-1) and (137)Cs concentration in bones was below the detection limit of 0.15 Bq kg(-1). (137)Cs activity varied over an order of magnitude in caribou muscle samples with an average value of 2.5 Bq/kg wet wt. Average (137)Cs activity in muskoxen muscle was found to be 9.7 Bq/kg wet wt. However, there were a little variation (less than 60%) in (210)Pb, (40)K, and (226)Ra in both muscle and bone of both caribou and muskoxen. The activities of total (210)Pb in caribou and muskox bones were found to be 1-2 orders of magnitude higher than that of parent-supported (210)Pb indicating the potential for dating of bones of terrestrial mammals (time elapsed since the death of the animal) based on the excess (210)Pb method exists. In fish muscle samples, (137)Cs activity varied from below detection limit to 154 mBq/kg wet wt. and its content increased with the size of the fish due to its transfer through the food chain. Among the seven fish species investigated, (210)Pb activities varied almost an order of magnitude; however, (40)K and (226)Ra activities varied less than a factor of two. Total annual effective dose due to (90)Sr and (137)Cs from the ingestion of those terrestrial and marine meats was estimated to be negligible (ca. 9 μSV/a) compared to the natural radionuclides present thus posing negligible radiological threat to humans.

  10. Anthropogenic and natural radionuclides in caribou and muskoxen in the western Alaskan Arctic and marine fish in the Aleutian Islands in the first half of 2000s.

    PubMed

    Hong, Gi Hoon; Baskaran, Mark; Molaroni, Shannon Marie; Lee, Hyun-Mi; Burger, Joanna

    2011-09-01

    A number of caribou and muskoxen samples from the western Alaskan Arctic and fish samples from the Aleutian Islands were collected between 1998 and 2006 and analyzed for anthropogenic ((90)Sr and (137)Cs) and natural radionculides ((40)K, (210)Pb and (226)Ra), as part of the radiological assessment for the regional subsistence hunting communities in the first half of 2000s. We examined the relationship between the activities of these nuclides with the size of the fish. In caribou samples, concentration of (90)Sr in muscle was below the detection limit of 0.14 Bq kg(-1) and (137)Cs concentration in bones was below the detection limit of 0.15 Bq kg(-1). (137)Cs activity varied over an order of magnitude in caribou muscle samples with an average value of 2.5 Bq/kg wet wt. Average (137)Cs activity in muskoxen muscle was found to be 9.7 Bq/kg wet wt. However, there were a little variation (less than 60%) in (210)Pb, (40)K, and (226)Ra in both muscle and bone of both caribou and muskoxen. The activities of total (210)Pb in caribou and muskox bones were found to be 1-2 orders of magnitude higher than that of parent-supported (210)Pb indicating the potential for dating of bones of terrestrial mammals (time elapsed since the death of the animal) based on the excess (210)Pb method exists. In fish muscle samples, (137)Cs activity varied from below detection limit to 154 mBq/kg wet wt. and its content increased with the size of the fish due to its transfer through the food chain. Among the seven fish species investigated, (210)Pb activities varied almost an order of magnitude; however, (40)K and (226)Ra activities varied less than a factor of two. Total annual effective dose due to (90)Sr and (137)Cs from the ingestion of those terrestrial and marine meats was estimated to be negligible (ca. 9 μSV/a) compared to the natural radionuclides present thus posing negligible radiological threat to humans. PMID:21774963

  11. TRANSPORTATION ISSUES IN THE DELIVERY OF GTL PRODUCTS FROM ALASKAN NORTH SLOPE TO MARKET

    SciTech Connect

    Godwin Chukwu

    2004-01-01

    The Alaskan North Slope (ANS) is one of the largest hydrocarbon reserves in the United States where Gas-to-Liquids (GTL) technology can be successfully implemented. The proven and recoverable reserves of conventional natural gas in the developed and undeveloped fields in the Alaskan North Slope (ANS) are estimated to be 38 trillion standard cubic feet (TCF) and estimates of additional undiscovered gas reserves in the Arctic field range from 64 TCF to 142 TCF. Because the domestic gas market in the continental United States is located thousands of miles from the ANS, transportation of the natural gas from the remote ANS to the market is the key issue in effective utilization of this valuable and abundant resource. The focus of this project is to study the operational challenges involved in transporting the gas in converted liquid (GTL) form through the existing Trans Alaska Pipeline System (TAPS). A three-year, comprehensive research program was undertaken by the Petroleum Development Laboratory, University of Alaska Fairbanks, under cooperative agreement No. DE-FC26-98FT40016 to study the feasibility of transporting GTL products through TAPS. Cold restart of TAPS following an extended winter shutdown and solids deposition in the pipeline were identified as the main transportation issues in moving GTL products through the pipeline. The scope of work in the current project (Cooperative Agreement No. DE-FC26-01NT41248) included preparation of fluid samples for the experiments to be conducted to augment the comprehensive research program.

  12. Seasonal Storminess in the North Pacific, Bering Sea, and Alaskan Regions

    NASA Astrophysics Data System (ADS)

    Shippee, N. J.; Atkinson, D. E.; Walsh, J. E.; Partain, J.; Gottschalck, J.; Marra, J.

    2012-12-01

    Annually, extra-tropical cyclones present a high impact natural hazard to the North Pacific, Bering Sea, and Alaskan regions. In these regions, extensive subsistence and commercial fishing, new oil and gas field development, tourism, growing interest in and exploitation of new commercial shipping potential, and increasing military and Coast Guard activity, all represent potential parties impacted by storms in these waters. It is of interest to many parties to begin developing capacity to provide some indication of storm activity at a monthly- to seasonal-outlook (30 to 90 days) timeframe. Using storm track data from NOAA's Climate Prediction Center for the North Pacific and Alaskan region, an experimental seasonal storminess outlook product, using eigen-based methods similar to the operational seasonal temperature and precipitation products currently produced at NOAA CPC, has been created and tested in hindcast mode using predicted states of ENSO, the Pacific Decadal Oscillation (PDO), the Pacific-North American Pattern (PNA), and the Arctic Oscillation (AO). A sample of the seasonal storminess outlook product will be shown along with a discussion of the utility of individual teleconnection patterns in the generation of the product.

  13. Spatial variability and landscape controls of near-surface permafrost within the Alaskan Yukon River Basin

    USGS Publications Warehouse

    Pastick, Neal J.; Jorgenson, M. Torre; Wylie, Bruce K.; Rose, Joshua R.; Rigge, Matthew; Walvoord, Michelle A.

    2014-01-01

    The distribution of permafrost is important to understand because of permafrost's influence on high-latitude ecosystem structure and functions. Moreover, near-surface (defined here as within 1 m of the Earth's surface) permafrost is particularly susceptible to a warming climate and is generally poorly mapped at regional scales. Subsequently, our objectives were to (1) develop the first-known binary and probabilistic maps of near-surface permafrost distributions at a 30 m resolution in the Alaskan Yukon River Basin by employing decision tree models, field measurements, and remotely sensed and mapped biophysical data; (2) evaluate the relative contribution of 39 biophysical variables used in the models; and (3) assess the landscape-scale factors controlling spatial variations in permafrost extent. Areas estimated to be present and absent of near-surface permafrost occupy approximately 46% and 45% of the Alaskan Yukon River Basin, respectively; masked areas (e.g., water and developed) account for the remaining 9% of the landscape. Strong predictors of near-surface permafrost include climatic indices, land cover, topography, and Landsat 7 Enhanced Thematic Mapper Plus spectral information. Our quantitative modeling approach enabled us to generate regional near-surface permafrost maps and provide essential information for resource managers and modelers to better understand near-surface permafrost distribution and how it relates to environmental factors and conditions.

  14. Using smooth sheets to describe groundfish habitat in Alaskan waters, with specific application to two flatfishes

    NASA Astrophysics Data System (ADS)

    Zimmermann, Mark; Reid, Jane A.; Golden, Nadine

    2016-10-01

    In this analysis we demonstrate how preferred fish habitat can be predicted and mapped for juveniles of two Alaskan groundfish species - Pacific halibut (Hippoglossus stenolepis) and flathead sole (Hippoglossoides elassodon) - at five sites (Kiliuda Bay, Izhut Bay, Port Dick, Aialik Bay, and the Barren Islands) in the central Gulf of Alaska. The method involves using geographic information system (GIS) software to extract appropriate information from National Ocean Service (NOS) smooth sheets that are available from NGDC (the National Geophysical Data Center). These smooth sheets are highly detailed charts that include more soundings, substrates, shoreline and feature information than the more commonly-known navigational charts. By bringing the information from smooth sheets into a GIS, a variety of surfaces, such as depth, slope, rugosity and mean grain size were interpolated into raster surfaces. Other measurements such as site openness, shoreline length, proportion of bay that is near shore, areas of rocky reefs and kelp beds, water volumes, surface areas and vertical cross-sections were also made in order to quantify differences between the study sites. Proper GIS processing also allows linking the smooth sheets to other data sets, such as orthographic satellite photographs, topographic maps and precipitation estimates from which watersheds and runoff can be derived. This same methodology can be applied to larger areas, taking advantage of these free data sets to describe predicted groundfish essential fish habitat (EFH) in Alaskan waters.

  15. Fine-scale population genetic structure in Alaskan Pacific halibut (Hippoglossus stenolepis)

    USGS Publications Warehouse

    2010-01-01

    Pacific halibut collected in the Aleutian Islands, Bering Sea and Gulf of Alaska were used to test the hypothesis of genetic panmixia for this species in Alaskan marine waters. Nine microsatellite loci and sequence data from the mitochondrial (mtDNA) control region were analyzed. Eighteen unique mtDNA haplotypes were found with no evidence of geographic population structure. Using nine microsatellite loci, significant heterogeneity was detected between Aleutian Island Pacific halibut and fish from the other two regions (FST range = 0.007–0.008). Significant FST values represent the first genetic evidence of divergent groups of halibut in the central and western Aleutian Archipelago. No significant genetic differences were found between Pacific halibut in the Gulf of Alaska and the Bering Sea leading to questions about factors contributing to separation of Aleutian halibut. Previous studies have reported Aleutian oceanographic conditions at deep inter-island passes leading to ecological discontinuity and unique community structure east and west of Aleutian passes. Aleutian Pacific halibut genetic structure may result from oceanographic transport mechanisms acting as partial barriers to gene flow with fish from other Alaskan waters.

  16. TISSUE DISTRIBUTION OF PCBS AND ORGANOCHLORINE PESTICIDES IN ALASKAN NORTHERN FUR SEALS: COMPARISON OF VARIOUS CONGENER CLASSIFICATION SCHEMES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are believed to adversely affect reproduction and cause health problems in Pinnipeds 1-4. In this study, 145 PCB congeners and OCPs were analyzed in 10 juvenile male northern fur seals, Callorhinus ursinus, collected from Alaskan...

  17. Long-Term Effects of Otitis Media a Ten-Year Cohort Study of Alaskan Eskimo Children

    ERIC Educational Resources Information Center

    Kaplan, Gary J.; And Others

    1973-01-01

    Histories of ear disease, otoscopic examinations, and audiologic, intelligence, and achievement tests were obtained from a cohort of 489 Alaskan Eskimo children, followed through the first 10 years of life, to determine whether otitis media (middle ear inflammation) deleteriously affected intellectual functioning and achievement in school.…

  18. Urban American Indian/Alaskan Natives Compared to Non-Indians in Out-of-Home Care

    ERIC Educational Resources Information Center

    Carter, Vernon B.

    2011-01-01

    Historically, American Indian/Alaskan Native (AI/AN) children have been disproportionately represented in the foster care system. In this study, nationally representative child welfare data from October 1999 was used to compare urban AI/AN children to non-Indian children placed into out-of-home care. Compared to non-Indian children, urban AI/AN…

  19. Population structure over a broad spatial scale driven by nonanthropogenic factors in a wide-ranging migratory mammal, Alaskan caribou.

    PubMed

    Mager, Karen H; Colson, Kevin E; Groves, Pam; Hundertmark, Kris J

    2014-12-01

    Wide-ranging mammals face significant conservation threats, and knowledge of the spatial scale of population structure and its drivers is needed to understand processes that maintain diversity in these species. We analysed DNA from 655 Alaskan caribou (Rangifer tarandus granti) from 20 herds that vary in population size, used 19 microsatellite loci to document genetic diversity and differentiation in Alaskan caribou, and examined the extent to which genetic differentiation was associated with hypothesized drivers of population subdivision including landscape features, population size and ecotype. We found that Alaskan caribou are subdivided into two hierarchically structured clusters: one group on the Alaska Peninsula containing discrete herds and one large group on the Mainland lacking differentiation between many herds. Population size, geographic distance, migratory ecotype and the Kvichak River at the nexus of the Alaska Peninsula were associated with genetic differentiation. Contrary to previous hypotheses, small Mainland herds were often differentiated genetically from large interconnected herds nearby, and genetic drift coupled with reduced gene flow may explain this pattern. Our results raise the possibility that behaviour helps to maintain genetic differentiation between some herds of different ecotypes. Alaskan caribou show remarkably high diversity and low differentiation over a broad geographic scale. These results increase information for the conservation of caribou and other migratory mammals threatened by population reductions and landscape barriers and may be broadly applicable to understanding the spatial scale and ecological drivers of population structure in widespread species. PMID:25403098

  20. Population structure over a broad spatial scale driven by nonanthropogenic factors in a wide-ranging migratory mammal, Alaskan caribou.

    PubMed

    Mager, Karen H; Colson, Kevin E; Groves, Pam; Hundertmark, Kris J

    2014-12-01

    Wide-ranging mammals face significant conservation threats, and knowledge of the spatial scale of population structure and its drivers is needed to understand processes that maintain diversity in these species. We analysed DNA from 655 Alaskan caribou (Rangifer tarandus granti) from 20 herds that vary in population size, used 19 microsatellite loci to document genetic diversity and differentiation in Alaskan caribou, and examined the extent to which genetic differentiation was associated with hypothesized drivers of population subdivision including landscape features, population size and ecotype. We found that Alaskan caribou are subdivided into two hierarchically structured clusters: one group on the Alaska Peninsula containing discrete herds and one large group on the Mainland lacking differentiation between many herds. Population size, geographic distance, migratory ecotype and the Kvichak River at the nexus of the Alaska Peninsula were associated with genetic differentiation. Contrary to previous hypotheses, small Mainland herds were often differentiated genetically from large interconnected herds nearby, and genetic drift coupled with reduced gene flow may explain this pattern. Our results raise the possibility that behaviour helps to maintain genetic differentiation between some herds of different ecotypes. Alaskan caribou show remarkably high diversity and low differentiation over a broad geographic scale. These results increase information for the conservation of caribou and other migratory mammals threatened by population reductions and landscape barriers and may be broadly applicable to understanding the spatial scale and ecological drivers of population structure in widespread species.

  1. American Indian/Alaskan Native Undergraduate Retention at Predominantly White Institutions: An Elaboration of Tinto's Theory of College Student Departure

    ERIC Educational Resources Information Center

    Lee, Junghee; Donlan, William; Brown, Eddie F.

    2011-01-01

    This article reports findings from a major public university sponsored study undertaken with the intention of (a) improving university understanding of factors affecting American Indian/Alaskan Native (AI/AN) undergraduates' persistence at this institution, and (b) identifying in what areas, and in what manner, this institution could improve…

  2. Social Disruption and Psychological Stress in an Alaskan Fishing Community: The Impact of the Exxon Valdez Oil Spill.

    ERIC Educational Resources Information Center

    Picou, J. Steven; And Others

    Technological accidents such as the Exxon Valdez oil spill in 1989 create man-made disaster situations that threaten community survival and the well-being and quality of life of community residents. This paper focuses on the social and psychological impact of the 1989 oil spill on Cordova, an isolated Alaskan community with high economic…

  3. STARCH/PULP-FIBER BASED PACKAGING FOAMS AND CAST FILMS CONTAINING ALASKAN FISH BY-PRODUCTS (WASTE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Baked starch/pulp foams were prepared from formulations containing 0-25% (wt%) of processed Alaskan fish by-products that consisted mostly of salmon heads, pollock heads and pollock frames (bones and associated remains produced in the filleting operation). Fish by-products thermoformed well along wi...

  4. Late nineteenth to early twenty-first century behavior of Alaskan glaciers as indicators of changing regional climate

    USGS Publications Warehouse

    Molnia, B.F.

    2007-01-01

    Alaska's climate is changing and one of the most significant indications of this change has been the late 19th to early 21st century behavior of Alaskan glaciers. Weather station temperature data document that air temperatures throughout Alaska have been increasing for many decades. Since the mid-20th century, the average change is an increase of ?????2.0????C. In order to determine the magnitude and pattern of response of glaciers to this regional climate change, a comprehensive analysis was made of the recent behavior of hundreds of glaciers located in the eleven Alaskan mountain ranges and three island areas that currently support glaciers. Data analyzed included maps, historical observations, thousands of ground-and-aerial photographs and satellite images, and vegetation proxy data. Results were synthesized to determine changes in length and area of individual glaciers. Alaskan ground photography dates from 1883, aerial photography dates from 1926, and satellite photography and imagery dates from the early 1960s. Unfortunately, very few Alaskan glaciers have any mass balance observations. In most areas analyzed, every glacier that descends below an elevation of ?????1500??m is currently thinning and/or retreating. Many glaciers have an uninterrupted history of continuous post-Little-Ice-Age retreat that spans more than 250??years. Others are characterized by multiple late 19th to early 21st century fluctuations. Today, retreating and/or thinning glaciers represent more than 98% of the glaciers examined. However, in the Coast Mountains, St. Elias Mountains, Chugach Mountains, and the Aleutian Range more than a dozen glaciers are currently advancing and thickening. Many currently advancing glaciers are or were formerly tidewater glaciers. Some of these glaciers have been expanding for more than two centuries. This presentation documents the post-Little-Ice-Age behavior and variability of the response of many Alaskan glaciers to changing regional climate. ?? 2006.

  5. Formative Assessment Probes: Wet Jeans

    ERIC Educational Resources Information Center

    Keeley, Page

    2015-01-01

    Picture a wet towel or a puddle of water on a hot, sunny day. An hour later, the towel is dry and the puddle no longer exists. What happened to the water? Where did it go? These are questions that reveal myriad interesting student ideas about evaporation and the water cycle--ideas that provide teachers with a treasure trove of data they can use to…

  6. Phoenix's Wet Chemistry Laboratory Units

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image shows four Wet Chemistry Laboratory units, part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument on board NASA's Phoenix Mars Lander. This image was taken before Phoenix's launch on August 4, 2007.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. Competitive Wetting in Active Brazes

    SciTech Connect

    Chandross, Michael Evan

    2014-05-01

    We found that the wetting and spreading of molten filler materials (pure Al, pure Ag, and AgAl alloys) on a Kovar ™ (001) substrate was studied with molecular dynamics simulations. A suite of different simulations was used to understand the effects on spreading rates due to alloying as well as reactions with the substrate. Moreover, the important conclusion is that the presence of Al in the alloy enhances the spreading of Ag, while the Ag inhibits the spreading of Al.

  8. Wetting hysteresis induced by nanodefects.

    PubMed

    Giacomello, Alberto; Schimmele, Lothar; Dietrich, Siegfried

    2016-01-19

    Wetting of actual surfaces involves diverse hysteretic phenomena stemming from ever-present imperfections. Here, we clarify the origin of wetting hysteresis for a liquid front advancing or receding across an isolated defect of nanometric size. Various kinds of chemical and topographical nanodefects, which represent salient features of actual heterogeneous surfaces, are investigated. The most probable wetting path across surface heterogeneities is identified by combining, within an innovative approach, microscopic classical density functional theory and the string method devised for the study of rare events. The computed rugged free-energy landscape demonstrates that hysteresis emerges as a consequence of metastable pinning of the liquid front at the defects; the barriers for thermally activated defect crossing, the pinning force, and hysteresis are quantified and related to the geometry and chemistry of the defects allowing for the occurrence of nanoscopic effects. The main result of our calculations is that even weak nanoscale defects, which are difficult to characterize in generic microfluidic experiments, can be the source of a plethora of hysteretical phenomena, including the pinning of nanobubbles. PMID:26721395

  9. Different regimes of dynamic wetting

    NASA Astrophysics Data System (ADS)

    Gustav, Amberg; Wang, Jiayu; Do-Quang, Minh; Shiomi, Junichiro; Physiochemical fluid mechanics Team; Maruyama-Chiashi Laboratory Team

    2014-11-01

    Dynamic wetting, as observed when a droplet contacts a dry solid surface, is important in various engineering processes, such as printing, coating, and lubrication. Our overall aim is to investigate if and how the detailed properties of the solid surface influence the dynamics of wetting. Here we discuss how surface roughness influences the initial dynamic spreading of a partially wetting droplet by studying the spreading on a solid substrate patterned with microstructures just a few micrometers in size. This is complemented by matching numerical simulations. We present a parameter map, based on the properties of the liquid and the solid surface, which identifies qualitatively different spreading regimes, where the spreading speed is limited by either the liquid viscosity, the surface properties, or the liquid inertia. The peculiarities of the different spreading regimes are studied by detailed numerical simulations, in conjuction with experiments. This work was financially supported in part by, the Japan Society for the Promotion of Science (J.W. and J.S) and Swedish Governmental Agency for Innovation Systems (M.D.-Q. and G.A).

  10. Wetting hysteresis induced by nanodefects

    PubMed Central

    Giacomello, Alberto; Schimmele, Lothar; Dietrich, Siegfried

    2016-01-01

    Wetting of actual surfaces involves diverse hysteretic phenomena stemming from ever-present imperfections. Here, we clarify the origin of wetting hysteresis for a liquid front advancing or receding across an isolated defect of nanometric size. Various kinds of chemical and topographical nanodefects, which represent salient features of actual heterogeneous surfaces, are investigated. The most probable wetting path across surface heterogeneities is identified by combining, within an innovative approach, microscopic classical density functional theory and the string method devised for the study of rare events. The computed rugged free-energy landscape demonstrates that hysteresis emerges as a consequence of metastable pinning of the liquid front at the defects; the barriers for thermally activated defect crossing, the pinning force, and hysteresis are quantified and related to the geometry and chemistry of the defects allowing for the occurrence of nanoscopic effects. The main result of our calculations is that even weak nanoscale defects, which are difficult to characterize in generic microfluidic experiments, can be the source of a plethora of hysteretical phenomena, including the pinning of nanobubbles. PMID:26721395

  11. Wetting hysteresis induced by nanodefects.

    PubMed

    Giacomello, Alberto; Schimmele, Lothar; Dietrich, Siegfried

    2016-01-19

    Wetting of actual surfaces involves diverse hysteretic phenomena stemming from ever-present imperfections. Here, we clarify the origin of wetting hysteresis for a liquid front advancing or receding across an isolated defect of nanometric size. Various kinds of chemical and topographical nanodefects, which represent salient features of actual heterogeneous surfaces, are investigated. The most probable wetting path across surface heterogeneities is identified by combining, within an innovative approach, microscopic classical density functional theory and the string method devised for the study of rare events. The computed rugged free-energy landscape demonstrates that hysteresis emerges as a consequence of metastable pinning of the liquid front at the defects; the barriers for thermally activated defect crossing, the pinning force, and hysteresis are quantified and related to the geometry and chemistry of the defects allowing for the occurrence of nanoscopic effects. The main result of our calculations is that even weak nanoscale defects, which are difficult to characterize in generic microfluidic experiments, can be the source of a plethora of hysteretical phenomena, including the pinning of nanobubbles.

  12. Potential effects of oil spills and other chemical pollutants on marine mammals occurring in Alaskan waters

    SciTech Connect

    Hansen, D.J.

    1985-01-01

    The outer continental shelf report describes and assesses the potential effects of oil spills and other contaminants on marine mammals that occur in Alaskan waters, assuming that a spill or contamination occurs. The report focuses primarily on the potential direct and indirect effects of oil spills on marine mammals and addresses both short-term effects that may occur at the time of contact with oil, and long-term effects that may occur long after contact with oil. The report also briefly reviews the literature on the potential effects of other contaminants such as heavy metals and organochlorines (DDT and PCB's) on marine mammals. The assessment concludes that sea otters, polar bears, fur seals, and very young seal pups could suffer serious or lethal effects if contact with oil occurred.

  13. Recent physical connections may explain weak genetic structure in western Alaskan chum salmon (Oncorhynchus keta) populations

    PubMed Central

    Garvin, Michael R; Kondzela, Christine M; Martin, Patrick C; Finney, Bruce; Guyon, Jeffrey; Templin, William D; DeCovich, Nick; Gilk-Baumer, Sara; Gharrett, Anthony J

    2013-01-01

    Low genetic divergence at neutral loci among populations is often the result of high levels of contemporary gene flow. Western Alaskan summer-run chum salmon (Oncorhynchus keta) populations demonstrate weak genetic structure, but invoking contemporary gene flow as the basis for the low divergence is problematic because salmon home to their natal streams and some of the populations are thousands of kilometers apart. We used genotypes from microsatellite and single nucleotide polymorphism loci to investigate alternative explanations for the current genetic structure of chum salmon populations from western Alaska. We also estimated current levels of gene flow among Kuskokwim River populations. Our results suggest that weak genetic structure is best explained by physical connections that occurred after the Holocene Thermal Maximum among the Yukon, Kuskokwim, and Nushagak drainages that allowed gene flow to occur among now distant populations. PMID:23919176

  14. All-weather ice information system for Alaskan arctic coastal shipping

    NASA Technical Reports Server (NTRS)

    Gedney, R. T.; Jirberg, R. J.; Schertler, R. J.; Mueller, R. A.; Chase, T. L.; Kramarchuk, I.; Nagy, L. A.; Hanlon, R. A.; Mark, H.

    1977-01-01

    A near real-time ice information system designed to aid arctic coast shipping along the Alaskan North Slope is described. The system utilizes a X-band Side Looking Airborne Radar (SLAR) mounted aboard a U.S. Coast Guard HC-130B aircraft. Radar mapping procedures showing the type, areal distribution and concentration of ice cover were developed. In order to guide vessel operational movements, near real-time SLAR image data were transmitted directly from the SLAR aircraft to Barrow, Alaska and the U.S. Coast Guard icebreaker Glacier. In addition, SLAR image data were transmitted in real time to Cleveland, Ohio via the NOAA-GOES Satellite. Radar images developed in Cleveland were subsequently facsimile transmitted to the U.S. Navy's Fleet Weather Facility in Suitland, Maryland for use in ice forecasting and also as a demonstration back to Barrow via the Communications Technology Satellite.

  15. Issues facing the future use of Alaskan NorthSlope natural gas

    SciTech Connect

    Bowsher, C.A.

    1983-05-12

    The North Slope of Alaska contains over 26 trillion cubic feet of natural gas. In 1977, the President and the Congress approved construction of a 4800-mile gas pipeline to bring this gas to US consumers by 1983. However, completion of the project is not now expected until late 1989 at the earliest. This report examines the status and outlook for the Alaskan gas pipeline (the Alaska Natural Gas Transportation System). It also evaluates the pros and cons of (1) alternative systems to deliver this gas to market, including a gas pipeline with Alaska for export of liquefied natural gas; (2) processing the gas in Alaska by converting it to methanol and petrochemicals for export; and (3) using the gas within Alaska.

  16. The influence of the Alaskan Gyre on the coastal circulation in the Gulf of Alaska

    NASA Technical Reports Server (NTRS)

    Heim, Paul K., II; Johnson, Mark A.; O'Brien, James J.

    1992-01-01

    The circulation of the northeast Pacific Ocean and the Gulf of Alaska is simulated by means of a reduced-gravity wind-driven model to study seasonal and interannual flow variability. The circulation in the NE Pacific is discussed emphasizing its ramifications for the physical domain, equations, and boundary conditions of the numerical model. The pseudostress fields used to drive the model are based on 20 years of data from the Comprehensive Ocean-Atmosphere Data Set and are analyzed with empirical orthogonal function analysis. The monthly stresses from 1986-89 are used to drive the model, and regional oceanographic features are reproduced including the Alaskan Gyre, Coastal Current, the Sitka eddy, and a severe cyclonic eddy. Comparisons with experimental data show that the high-resolution baroclinic model is valid and demonstrates the applicability of reduced-gravity models.

  17. Bowhead whale behavior in relation to seismic exploration, Alaskan Beaufort Sea, Autumn 1981. Study report (Final)

    SciTech Connect

    Fraker, M.A.; Ljungblad, D.K.; Richardson, W.J.; Van Schoik, D.R.

    1985-10-01

    Behavior of bowhead whales (Balsena mysticetus) in the eastern part of the Alaskan Beaufort Sea or near the Alaska/Yukon border was observed from a circling turbine-powered Goose aircraft on 10 dates from 12 September to 5 October 1981. On three of these dates, the whales were exposed t, noise impulses from seismic vessels 13 km or more away. Some behavioral data were acquired. In both the presence and the absence of seismic impulses, most bowheads appeared to be feeding in the water column, although slow travel and active socializing were sometimes detected. Sonobuoys detected bowhead calls both in the presence and the absence of seismic impulses. There was no clear evidence of unusual behavior in the presence of seismic impulses.

  18. Digital depth horizon compilations of the Alaskan North Slope and adjacent Arctic regions

    USGS Publications Warehouse

    Saltus, Richard W.; Bird, Kenneth J.

    2003-01-01

    Data have been digitized and combined to create four detailed depth horizon grids spanning the Alaskan North Slope and adjacent offshore areas. These map horizon compilations were created to aid in petroleum system modeling and related studies. Topography/bathymetry is extracted from a recent Arctic compilation of global onshore DEM and satellite altimetry and ship soundings offshore. The Lower Cretaceous Unconformity (LCU), the top of the Triassic Shublik Formation, and the pre-Carboniferous acoustic basement horizon grids are created from numerous seismic studies, drill hole information, and interpolation. These horizons were selected because they mark critical times in the geologic evolution of the region as it relates to petroleum. The various horizons clearly show the major tectonic elements of this region including the Brooks Range, Colville Trough, Barrow Arch, Hanna Trough, Chukchi Platform, Nuwuk Basin, Kaktovik Basin, and Canada Basin. The gridded data are available in a variety of data formats for use in regional studies.

  19. Quantifying the historic and future distribution of fire in Alaskan tundra ecosystems

    NASA Astrophysics Data System (ADS)

    Young, A. M.; Higuera, P. E.; Duffy, P. A.

    2012-12-01

    During the past 60 years fire has been relatively rare and small in size within tundra ecosystems. However, historical observations and paleoecological evidence indicates that fire regimes vary widely across Alaskan tundra, in both space and time. These lines of evidence suggest that fire occupies a highly specified niche or ecological space in Alaskan tundra, which may change significantly with future climate warming. The objective of this research was to quantify the relationships between fire occurrence and different seasonal climate variables, and to begin to make inferences about future distributions of fire across the tundra landscape. The results of this research will ultimately contribute to the goal of summarizing the linkages that exist among climate, vegetation, and fire in the historical record, and for making predictions concerning fire disturbance in tundra ecosystems throughout the next century. Historic tundra fires occurred non-randomly across space, and a relationship exists between fire occurrence and warm, dry climates. We quantified this relationship with generalized boosting models (GBM) using datasets of downscaled temperature and precipitation (2 km, 1971-2000), and historic records of tundra area burned (1950-2010). The GBM used six seasonal climate variables, focused on growing season temperature and precipitation, to predict the probability of fire occurrence over the 1950-2010 time period. To understand implications of these historic relationships given ongoing climate warming, we constructed future climatologies of temperature and precipitation for the five GCMs which performed best in Alaska under the IPCC AR4 A1B (middle-of-the-road) emissions scenario for the time period 2021-2050. The GBM performed well predicting the observed spatial distribution of tundra area burned, capturing key regions which experienced the most fire activity from 1950-2010. The mean temperature of the warmest month (MeanMaxTemp) was the most influential

  20. Frequency of genes in aromatic and aliphatic hydrocarbon biodegradation pathways within bacterial populations from Alaskan sediments.

    PubMed

    Sotsky, J B; Greer, C W; Atlas, R M

    1994-11-01

    A significant proportion of the naturally occurring hydrocarbon-degrading populations within Alaskan sediments affected by the Exxon Valdez oil spill had both the xylE and alkB genes and could convert hexadecane and naphthalene to carbon dioxide; a greater proportion of the population had xylE than had alkB, reflecting the composition of the residual oil at the time of sampling; nearly equal populations with xylE alone, alkB alone, and xylE + alkB genes together were found after exposure to fresh crude oil; populations with xylE lacking alkB increased after enrichment on naphthalene. Thus, the genotypes of hydrocarbon-degrading populations reflected the composition of the hydrocarbons to which they were exposed. PMID:7804909

  1. Recent and Holocene climate change controls on vegetation and carbon accumulation in Alaskan coastal muskegs

    NASA Astrophysics Data System (ADS)

    Peteet, Dorothy M.; Nichols, Jonathan E.; Moy, Christopher M.; McGeachy, Alicia; Perez, Max

    2016-01-01

    Pollen, spore, macrofossil and carbon data from a peatland near Cordova, Alaska, reveal insights into the climate-vegetation-carbon interactions from the initiation of the Holocene, c. the last 11.5 ka, to the present (1 ka = 1000 calibrated years before present where 0 = 1950 CE). The Holocene period is characterized by early deposition of gyttja in a pond environment with aquatics such as Nuphar polysepalum and Potamogeton, and a significant regional presence of Alnus crispa subsp. sinuata. Carbon accumulation (50 g/m2/a) was high for a short interval in the early Holocene when Sphagnum peat accumulated, but was followed by a major decline to 13 g/m2/a from 7 to 3.7 ka when Cyperaceae and ericads such as Rhododendron (formerly Ledum) groenlandicum expanded. This shift to sedge growth is representative of many peatlands throughout the south-central region of Alaska, and indicates a drier, more evaporative environment with a large decline in carbon storage. The subsequent return to Sphagnum peat after 4 ka in the Neoglacial represents a widespread shift to moister, cooler conditions, which favored a resurgence of ericads, such as Andromeda polifolia, and increased carbon accumulation rate. The sustained Alnus expansion visible in the top 10 cm of the peat profile is correlative with glacial retreat and warming of the region in the last century, and suggests this colonization will continue as temperature increases and ice melts.

  2. Pleiotropic effects on subclasses of HDL, adiposity and glucose metabolism in adult Alaskan Eskimos

    PubMed Central

    Tejero, ME; Voruganti, VS; Cai, G; Cole, SA; Laston, S; Wenger, CR; MacCluer, JW; Dyke, B; Devereux, R; Ebbesson, SO; Fabsitz, RR; Howard, BV; Comuzzie, AG

    2012-01-01

    The aim of the present study was to analyze the heritability and the presence of pleiotropic effects on subfractions of high density lipoproteins (HDLs) as measured by nuclear magnetic resonance (NMR), parameters for adiposity and glucose metabolism in adult Alaskan Eskimos. The present family study included 1214 adult Alaskan Eskimos (537 male/677 female). Body weight, height, circumferences, selected skinfolds and blood pressure were measured in all participants. Blood samples were collected under fasting conditions for isolation of plasma. Glucose, insulin, subclasses and size of lipoproteins, triglycerides, total and HDL cholesterol and lipoprotein (a) were measured in plasma. HbA1c was measured in total blood. Univariate and bivariate quantitative genetic analyses were conducted between HDL subclasses and size and the anthropometric and biochemical measures using the variance decomposition approach. Variation in all the analyzed traits exhibits a significant genetic component. Heritabilities ranged between 0.18 ± 0.11 for LDL2 (intermediate) to 0.89 ± 0.07 for small HDL. No common genetic effects were found on the HDL subclasses (small, intermediate and large). Small HDL particles were genetically correlated with LDL particles and HbA1c. Negative genetic correlations were observed between intermediate and large HDL subfractions and HDL size and measures of adiposity, LDL and parameters for glucose metabolism (HbA1, insulin). These observations confirm the presence of possible pleiotropic effects on HDL, adiposity and cardiovascular risk factors and provide novel insight on the relationship between HDL subclasses, adiposity and glucose regulation. PMID:19950191

  3. Coal combustion by wet oxidation

    SciTech Connect

    Bettinger, J.A.; Lamparter, R.A.; McDowell, D.C.

    1980-11-15

    The combustion of coal by wet oxidation was studied by the Center for Waste Management Programs, of Michigan Technological University. In wet oxidation a combustible material, such as coal, is reacted with oxygen in the presence of liquid water. The reaction is typically carried out in the range of 204/sup 0/C (400/sup 0/F) to 353/sup 0/C (650/sup 0/F) with sufficient pressure to maintain the water present in the liquid state, and provide the partial pressure of oxygen in the gas phase necessary to carry out the reaction. Experimental studies to explore the key reaction parameters of temperature, time, oxidant, catalyst, coal type, and mesh size were conducted by running batch tests in a one-gallon stirred autoclave. The factors exhibiting the greatest effect on the extent of reaction were temperature and residence time. The effect of temperature was studied from 204/sup 0/C (400/sup 0/F) to 260/sup 0/C (500/sup 0/F) with a residence time from 600 to 3600 seconds. From this data, the reaction activation energy of 2.7 x 10/sup 4/ calories per mole was determined for a high-volatile-A-Bituminous type coal. The reaction rate constant may be determined at any temperature from the activation energy using the Arrhenius equation. Additional data were generated on the effect of mesh size and different coal types. A sample of peat was also tested. Two catalysts were evaluated, and their effects on reaction rate presented in the report. In addition to the high temperature combustion, low temperature desulfurization is discussed. Desulfurization can improve low grade coal to be used in conventional combustion methods. It was found that 90% of the sulfur can be removed from the coal by wet oxidation with the carbon untouched. Further desulfurization studies are indicated.

  4. Mold management of wetted carpet.

    PubMed

    Ong, Kee-Hean; Dixit, Anupma; Lewis, Roger D; MacDonald Perkins, Maureen; Backer, Denis; Condoor, Sridhar; Emo, Brett; Yang, Mingan

    2014-01-01

    This study evaluated the growth and removal of fungi on wetted carpet using newly designed technologies that rely on physical principles of steam, heat, and fluid flow. Sixty samples of carpet were embedded with heat-treated house dust, followed by embedding, wearing with a hexapod, and wetting. Samples were inoculated using a liquid suspension of Cladosporium sphaerospermum prior to placement over a water-saturated foam pad. Incubation times were 24 hr, 7 days, and 30 days. Cleaning was performed using three methods; high-flow hot water extraction, hot water and detergent, and steam. Fungal loading increased from approximately 1500 colony forming units per area (CFU/cm(2)) in 24 hr to a maximum of approximately 10,200 CFU/cm(2) after 7 days with a slight decline to 9700 CFU/cm(2) after 30 days incubation. Statistically significant differences were found among all three methods for removal of fungi for all three time periods (p < 0.05). Steam-vapor was significantly better than the alternative methods (p <0.001) with over 99% efficiency in mold spore decline from wetted carpet after 24 hr and 30 days, and over 92% efficiency after 7 days. The alternative methods exhibited lower efficiencies with a decline over time, from a maximum of 82% and 81% at 24 hr down to 60% and 43% at 30 days for detergent-hot water and high-flow, hot water extraction, respectively. The net effect of the mold management study demonstrates that while steam has a consistent fungal removal rate, the detergent and high-flow, hot water methods decline in efficiency with increasing incubation time.

  5. Single-metalloprotein wet biotransistor

    NASA Astrophysics Data System (ADS)

    Alessandrini, Andrea; Salerno, Marco; Frabboni, Stefano; Facci, Paolo

    2005-03-01

    Metalloproteins are redox molecules naturally shuttling electrons with high efficiency between molecular partners. As such, they are candidates of choice for bioelectronics. In this work, we have used bacterial metalloprotein azurin, hosted in a nanometer gap between two electrically biased gold electrodes, to demonstrate an electrochemically gated single-molecule transistor operating in an aqueous environment. Gold-chemisorbed azurin shows peaks in tunneling current upon changing electrode potential and a related variation in tunneling barrier transparency which can be exploited to switch an electron current through it. These results suggest the wet approach to molecular electronics as a viable method for exploiting electron transfer of highly specialized biomolecules.

  6. A Wet Chemistry Laboratory Cell

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This picture of NASA's Phoenix Mars Lander's Wet Chemistry Laboratory (WCL) cell is labeled with components responsible for mixing Martian soil with water from Earth, adding chemicals and measuring the solution chemistry. WCL is part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument suite on board the Phoenix lander.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. Droplet charging for wet scrubbers.

    PubMed

    Pilat, Michael J; Lukas, John C

    2004-01-01

    Water droplet charge/mass of wet scrubbers was measured over the direct charging applied potential range of 0-20 kV, 30-70 pounds per square inch gauge (206.8-482.6 kPa) water pressure, and with spiral, impingement, and whirl nozzles. The measured charge/mass ranged from -0.0005 to 0.2 microcoulomb/gm and was directly related to the applied voltage. The water charge/mass was a function of the spray nozzle, with the smaller orifice lower-flow nozzles having the higher charge/mass.

  8. Placer and lode platinum-group minerals in south Kalimantan, Indonesia: evidence for derivation from Alaskan-type ultramafic intrusions

    USGS Publications Warehouse

    Zientek, M.L.

    1992-01-01

    Platinum-group minerals occur in significant proportions in placer deposits in several localities in South Kalimantan. They consist of Pt-Fe alloy that may be intergrown with or contain inclusions of Ir-Os-Ru alloy, laurite and chromite. Alluvial PGM found along Sungai Tambanio are in part derived from chromatite schlieren in dunitic bodies intruded into clinopyroxene cumulates that may be part of an Alaskan-type ultramafic complex. A chromitite schlieren in serpentinite from one of these dunitic bodies is anomalous in PGE. The chondrite-normalized PGE pattern for this rock, pan concentrates from this area, and PGM concentrates from diamond-Au-PGM placer deposits have an "M'-shaped pattern enriched in Ir and Pt that is typical of PGE-mineralization associated with Alaskan-type ultramafic complexes. -Authors

  9. Microbes residing in young organic rich Alaskan soils contain older carbon than those residing in old mineral high Arctic soils

    NASA Astrophysics Data System (ADS)

    Ziolkowski, L. A.; Slater, G. F.; Onstott, T. C.; Whyte, L.; Townsend-Small, A.

    2013-12-01

    Arctic soils range from very organic rich to low carbon and mineral-dominated soils. At present, we do not yet fully understand if all carbon in the Arctic is equally vulnerable to mineralization in a warmer climate. Many studies have demonstrated that ancient carbon is respired when permafrost has thawed, yet our understanding of the active layer and permafrost carbon dynamics is still emerging. In an effort to remedy this disconnect between our knowledge of surface fluxes and below ground processes, we used radiocarbon to examine the microbial carbon dynamics in soil cores from organic rich soils near Barrow, Alaska and mineral soils from the Canadian high Arctic. Specifically, we compared the microbial community using lipid biomarkers, the inputs of carbon using n-alkanes and measured the 14C of both the bulk organic carbon and of the microbial lipids. In theory, the microbial lipids (phospholipid fatty acids, PLFA) represent the viable microbial community, as these lipids are hydrolyzed quickly after cell death. Variations in the PLFA distributions suggested that different microbial communities inhabit organic rich Alaskan soils and those of the Canadian high Arctic. When the PLFA concentrations were converted to cellular concentration, they were within the same order of magnitude (1 to 5 x 108 cells/g dry soil) with slightly higher cell concentrations in the organic rich Alaskan soils. When these cellular concentrations were normalized to the organic carbon content, the Canadian high Arctic soils contained a greater proportion of microbes. Although bulk organic carbon 14C of Alaskan soils indicated more recent carbon inputs into the soil than the Canadian high Arctic soils, the 14C of the PLFA revealed the opposite. For corresponding depth horizons, microbes in Alaskan soils were consuming carbon 1000 to 1500 years older than those in the Canadian high Arctic. Differences between the 14C content of bulk organic carbon and the microbial lipids were much smaller

  10. Isolation of a complete circular virus genome sequence from an Alaskan black-capped chickadee (Poecile atricapillus) gastrointestinal tract sample.

    USGS Publications Warehouse

    Hanna, Zachary R.; Runckel, Charles; Fuchs, Jerome; DeRisi, Joseph L.; Mindell, David P.; Van Hemert, Caroline R.; Handel, Colleen M.; Dumbacher, John P.

    2015-01-01

    We report here the genome sequence of a circular virus isolated from samples of an Alaskan black-capped chickadee (Poecile atricapillus) gastrointestinal tract. The genome is 2,152 bp in length and is most similar (30 to 44.5% amino acid identity) to the genome sequences of other single-stranded DNA (ssDNA) circular viruses belonging to the gemycircularvirus group.

  11. Utility of a Work Process Classification System for characterizing non-fatal injuries in the Alaskan commercial fishing industry

    PubMed Central

    Syron, Laura N.; Lucas, Devin L.; Bovbjerg, Viktor E.; Bethel, Jeffrey W.; Kincl, Laurel D.

    2016-01-01

    Background The US commercial fishing industry is hazardous, as measured by mortality data. However, research on non-fatal injuries is limited. Non-fatal injuries constitute the majority of occupational injuries and can result in workers’ lowered productivity and wages, lost quality of life, and disability. In the United States, a Work Process Classification System (WPCS) has previously been applied in Alaskan freezer-trawl and freezer-longline fleets to identify causes of injuries and specific hazards, but not to other fishing fleets. Objectives This descriptive epidemiologic study aimed to explore the application and modification of the WPCS in multiple Alaskan fleets, characterize non-fatal occupational injuries in these fleets, and identify work processes that could be targeted for further investigation and future injury prevention efforts. Design Traumatic, non-fatal injuries on-board Alaskan commercial fishing vessels were identified through United States Coast Guard investigative reports. Characteristics of injuries, as well as worker characteristics, were analysed. Injuries were coded using the WPCS. Results We successfully utilized the WPCS to code non-fatal injury cases (n = 136). The most frequent main work processes associated with non-fatal injuries included: on-board trawlers, handling frozen fish and processing the catch; on-board vessels using pot/trap gear, handling the gear and shooting/setting the gear; on-board longliners, traffic on board and hauling the gear; and on-board processor vessels, processing the catch, other work with the catch, and handling frozen fish. Conclusions The study confirmed that a WPCS can be applied to multiple Alaskan fleets to identify hazardous tasks. Hazards were unique for each vessel gear type. Future injury prevention efforts should target work processes associated with the most frequent and most severe injuries. Future studies should establish time estimates for work processes in order to determine risk

  12. Mars: Always Cold, Sometimes Wet?

    NASA Technical Reports Server (NTRS)

    Lee, Pascal; McKay, Christoper P.

    2003-01-01

    A synthesis of a diverse suite of observations of H2O-related landforms that are possible Mars analogs from terrestrial polar regions (Devon Island in the Arctic; the Dry Valleys of Antarctica) put into question any requirement for extended episode(s) of warm and wet climate in Mars past. Geologically transient episodes of localized H2O cycling, forced by exogenic impacts, enhanced endogenic heat flow, and/or orbit-driven short-term local environmental change under an otherwise cold, low pressure (=10(exp 2) mbar) global climate, may be sufficient to account for the martian surface's exposed record of aqueous activity. A Mars that was only sometimes locally warm and wet while remaining climatically cold throughout its history is consistent with results (difficulties) encountered in modeling efforts attempting to support warm martian climate hypotheses. Possible analogs from terrestrial cold climate regions for the recent gully features on Mars also illustrate how transient localized aqueous activity might, under specific circumstances, also occur on Mars under the present frigid global climatic regime.

  13. This technology is all wet

    SciTech Connect

    1996-09-01

    The wet oxidation technology developed by Conor Pacific Environmental Technologies Inc. (CPET; Vancouver, British Columbia) is designed to eliminate hazardous and nonhazardous organic contaminants from liquid effluent. The technology, which originated in Denmark, uses oxygen homogeneously dissolved in water to treat organic contaminants. According to the company, the process eliminates hazardous and nonhazardous contaminants without generating pollutant emissions, making it relatively easy to permit. CPET says wet oxidation eliminates some inorganic compounds, such as cyanides, and all hazardous and nonhazardous organic pollutants, including those found in petroleum products, aromatic solvents, tar compounds, pesticides and plasticizers. The process also handles relatively high concentrations of such contaminants as phenol, oil, and coal, tar and wood preservatives. The technology can achieve up to 99.9999% destruction efficiencies. The process is exothermic, generating its own heat, and allows energy to be recovered and recycled. Some heating is required at start-up, and heat exchangers are used to overcome heat build-up later in the process.

  14. Elucidating the mysteries of wetting.

    SciTech Connect

    Webb, Edmund Blackburn, III; Bourdon, Christopher Jay; Grillet, Anne Mary; Sackinger, Philip A.; Grest, Gary Stephen; Emerson, John Allen; Ash, Benjamin Jesse; Heine, David R.; Brooks, Carlton, F.; Gorby, Allen D.

    2005-11-01

    Nearly every manufacturing and many technologies central to Sandia's business involve physical processes controlled by interfacial wetting. Interfacial forces, e.g. conjoining/disjoining pressure, electrostatics, and capillary condensation, are ubiquitous and can surpass and even dominate bulk inertial or viscous effects on a continuum level. Moreover, the statics and dynamics of three-phase contact lines exhibit a wide range of complex behavior, such as contact angle hysteresis due to surface roughness, surface reaction, or compositional heterogeneities. These thermodynamically and kinetically driven interactions are essential to the development of new materials and processes. A detailed understanding was developed for the factors controlling wettability in multicomponent systems from computational modeling tools, and experimental diagnostics for systems, and processes dominated by interfacial effects. Wettability probed by dynamic advancing and receding contact angle measurements, ellipsometry, and direct determination of the capillary and disjoining forces. Molecular scale experiments determined the relationships between the fundamental interactions between molecular species and with the substrate. Atomistic simulations studied the equilibrium concentration profiles near the solid and vapor interfaces and tested the basic assumptions used in the continuum approaches. These simulations provide guidance in developing constitutive equations, which more accurately take into account the effects of surface induced phase separation and concentration gradients near the three-phase contact line. The development of these accurate models for dynamic multicomponent wetting allows improvement in science based engineering of manufacturing processes previously developed through costly trial and error by varying material formulation and geometry modification.

  15. Transport and reaction of heavy metals in Alaskan fjord estuaries. Annual report, July 1, 1980-May 31, 1981

    SciTech Connect

    Burrell, D.C.

    1981-05-01

    The program investigates the potential effects of energy-related chemical pollution in Alaskan fjords. The long-term objective is to understand the chemical, physical, and biological processes responsible for the transport and reaction of heavy metals in these sub-arctic estuaries. The physical circulation and mixing processes, the nature and reactions of terrigenous organics and particulate sediment within the mixing zone, and aspects of the basin sediment oxygen, carbon and nutrient budgets in addition to study of individual metals are investigated. Mainly copper, iron and manganese are being studied since these provide information on physical-chemical processes common to, or greatly affecting, a much wider range of metals. The bulk of the Work completed section of this report refers to Resurrection Bay, a southcentral Alaskan fjord. The Work in progress reported here outlines recent investigations in Boca de Quadra, a southeast Alaskan fjord-estuary. We are here investigating deep and surface water circulation; oxygen, carbon and nutrient budgets; the compositions, reaction and flux of particulate sediment; and organic-heavy metal associations in the freshwater and in the mixing zone.

  16. Wetting and Non-Wetting Models of Black Carbon Activation

    NASA Astrophysics Data System (ADS)

    Henson, B. F.; Laura, S.

    2006-12-01

    We present the results of recent modeling studies on the activation of black carbon (BC) aerosol to form cloud condensation nuclei (CCN). We use a model of BC activation based on a general modification of the Koehler equation for insoluble activation in which we introduce a term based on the activity of water adsorbed on the particle surface. We parameterize the model using the free energy of adsorption, a parameter directly comparable to laboratory measurements of water adsorption on carbon. Although the model of the water- surface interaction is general, the form of the activation equation that results depends upon a further model of the distribution of water on the particle. One possible model involves the symmetric growth of a water shell around the isoluble particle core (wetting). This model predicts upper and lower bounding curves for the activation supersaturation given by the range of water interaction energies from hydrophobic to hydrophilic which are in agreement with a large body of recent activation data. The resulting activation diameters are from 3 to 10 times smaller than activation of soluble particles of identical dry diameter. Another possible model involves an exluded liquid droplet growing in contact with the particle (non-wetting). The geometry of this model much more resembles classic assumptions of heterogeneous nucleation theory. This model can yield extremely high activation supersaturation as a function of diameter, as has been observed in some experiments, and enables calculations in agreement with some of these results. We discuss these two geometrical models of water growth, the different behaviors predicted by the resulting activation equation, and the means to determine which model of growth is appropriate for a given BC particle characterized by either water interaction energy or morphology. These simple models enable an efficient and physically reasonable means to calculate the activation of BC aerosol to form CCN based upon a

  17. Spectral indices for remote sensing of phytomass and deciduous shrub changes in Alaskan arctic tundra

    NASA Astrophysics Data System (ADS)

    Kushida, K.; Hobara, S.; Tsuyuzaki, S.; Watanabe, M.; Harada, K.; Kim, Y.; Shaver, G. R.; Fukuda, M.

    2010-12-01

    The relationships between spectral indices, phytomass, and plant functional types were determined by using field observations of a moist acidic tundra (MAT) and a moist non-acidic tundra (MNT) in the Toolik Lake Long Term Ecological Research (LTER) site and a sedge-shrub tundra (SS) in the Arctic National Wildlife Refuge, Alaska, USA. For the MAT and MNT observations, among aboveground phytomass, aboveground vascular phytomass, and vascular plant green phytomass, vascular plant green phytomass was the most sensitive to an exponential function of the normalized difference vegetation index (NDVI). The coefficient of determination (R2) was 0.73. Vascular plant carbon and nitrogen were estimated with exponential functions of NDVI (R2 of 0.57 and 0.53, respectively). For the MAT, MNT, and SS observations, vascular plant green phytomass was more strongly correlated with an exponential function of NDVI (ENDVI, R2 of 0.62) than any other spectral indices. On the other hand, for deciduous shrub green phytomass, the strongest correlation was with a product of an exponential function of NDVI and a spectral index (MIR - RED)/(MIR + RED) (DSSI, R2 of 0.60). Here, MIR and RED denote the bands with wavelengths 2.09-2.35 and 0.63-0.69 µm, respectively. As a result of a regression analysis, 41% of the ENDVI variance and 60% of the DSSI variance were explained by deciduous shrub green phytomass. Up to 38% of the ENDVI variance and up to 10% of the DSSI variance were explained by green phytomass of evergreen shrubs and graminoids, and phytomass of mosses/lichens. These spectral indices were applicable to evaluating tundra plant community changes.

  18. Effects of migratory geese on plant communities of an Alaskan salt marsh

    USGS Publications Warehouse

    Zacheis, A.; Hupp, J.W.; Ruess, R.W.

    2001-01-01

    1. We studied the effects of lesser snow geese (Anser caerulescens caerulescens) and Canada geese (Branta canadensis) on two salt marsh plant communities in Cook Inlet, Alaska, a stopover area used during spring migration. From 1995 to 1997 we compared plant species composition and biomass on plots where geese were excluded from feeding with paired plots where foraging could occur. 2. Foraging intensity was low (650-1930 goose-days km-2) compared to other goose-grazing systems. 3. Canada geese fed mainly on above-ground shoots of Triglochin maritimum, Puccinellia spp. and Carex ramenskii, whereas the majority of the snow goose diet consisted of below-ground tissues of Plantago maritima and Triglochin maritimum. 4. Plant communities responded differently to goose herbivory. In the sedge meadow community, where feeding was primarily on above-ground shoots, there was no effect of grazing on the dominant species Carex ramenskii and Triglochin maritimum. In the herb meadow community, where snow geese fed on Plantago maritima roots and other below-ground tissues, there was a difference in the relative abundance of plant species between treatments. Biomass of Plantago maritima and Potentilla egedii was lower on grazed plots compared with exclosed, whereas biomass of Carex ramenskii was greater on grazed plots. There was no effect of herbivory on total standing crop biomass in either community. The variable effect of herbivory on Carex ramenskii between communities suggests that plant neighbours and competitive interactions are important factors in a species' response to herbivory. In addition, the type of herbivory (above- or below-ground) was important in determining plant community response to herbivory. 5. Litter accumulation was reduced in grazed areas compared with exclosed in both communities. Trampling of the previous year's litter into the soil surface by geese incorporated more litter into soils in grazed areas. 6. This study illustrates that even light herbivore

  19. Inter-annual variability in Alaskan net ecosystem CO2 exchange

    NASA Astrophysics Data System (ADS)

    Luus, Kristina; Lindaas, Jakob; Commane, Roisin; Euskirchen, Eugenie; Oechel, Walter; Zona, Donatella; Chang, Rachel; Kelly, Richard; Miller, Charles; Wofsy, Steven; Lin, John

    2015-04-01

    The high-latitude biospheric carbon cycle's responses to climate change are predicted to have an important role in determining future atmospheric concentrations of CO2. In response to warming soil and air temperatures, Arctic wetlands have been observed to increase rates of both soil C efflux and vegetation C uptake through photosynthesis. However, insights into the regional-scale consequences of these processes for net C uptake have been limited by the large uncertainties existing in process-based model estimates of Arctic net ecosystem CO2 exchange (NEE). The Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM) instead provides data-driven, satellite-based estimates of high-latitude NEE, using a framework which specifically accounts for polar influences on NEE. PolarVPRM calculates NEE as the sum of respiration (R) and gross ecosystem exchange (GEE), where GEE refers to the light-dependent portion of NEE: NEE= -GEE + R. Meteorological inputs for PolarVPRM are provided by the North American Regional Reanalysis (NARR), and land surface inputs are acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS). Growing season R is calculated from air temperature, and subnivean R is calculated according to soil temperature. GEE is calculated according to shortwave radiation, air temperature, and MODIS-derived estimates of soil moisture and vegetation biomass. Previously, model validation has indicated that PolarVPRM showed reasonably good agreement with eddy covariance observations at nine North American Arctic sites, of which three were used for calibration purposes. For this project, PolarVPRM NEE was calculated year-round across Alaska at a three-hourly temporal resolution and a spatial resolution of 1 6°×1 4° (latitude × longitude). The objective of this work was to gain insight into inter-annual variability in Alaskan NEE, R and GEE, and an understanding of which meteorological and land surface drivers account for these observed patterns

  20. Directional wetting in anisotropic inverse opals.

    PubMed

    Phillips, Katherine R; Vogel, Nicolas; Burgess, Ian B; Perry, Carole C; Aizenberg, Joanna

    2014-07-01

    Porous materials display interesting transport phenomena due to restricted motion of fluids within the nano- to microscale voids. Here, we investigate how liquid wetting in highly ordered inverse opals is affected by anisotropy in pore geometry. We compare samples with different degrees of pore asphericity and find different wetting patterns depending on the pore shape. Highly anisotropic structures are infiltrated more easily than their isotropic counterparts. Further, the wetting of anisotropic inverse opals is directional, with liquids filling from the side more easily. This effect is supported by percolation simulations as well as direct observations of wetting using time-resolved optical microscopy. PMID:24941308

  1. Carbon nanotube fiber spun from wetted ribbon

    SciTech Connect

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  2. Directional wetting in anisotropic inverse opals.

    PubMed

    Phillips, Katherine R; Vogel, Nicolas; Burgess, Ian B; Perry, Carole C; Aizenberg, Joanna

    2014-07-01

    Porous materials display interesting transport phenomena due to restricted motion of fluids within the nano- to microscale voids. Here, we investigate how liquid wetting in highly ordered inverse opals is affected by anisotropy in pore geometry. We compare samples with different degrees of pore asphericity and find different wetting patterns depending on the pore shape. Highly anisotropic structures are infiltrated more easily than their isotropic counterparts. Further, the wetting of anisotropic inverse opals is directional, with liquids filling from the side more easily. This effect is supported by percolation simulations as well as direct observations of wetting using time-resolved optical microscopy.

  3. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2002

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sánchez, John; Estes, Steve; McNutt, Stephen R.; Paskievitch, John

    2003-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001; Dixon and others, 2002). The primary objectives of this program are the seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the basic seismic data and changes in the seismic monitoring program for the period January 1, 2002 through December 31, 2002. Appendix G contains a list of publications pertaining to seismicity of Alaskan volcanoes based on these and previously recorded data. The AVO seismic network was used to monitor twenty-four volcanoes in real time in 2002. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). Monitoring highlights in 2002 include an earthquake swarm at Great Sitkin Volcano in May-June; an earthquake swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and long-period events at Mount Veniaminof in September-October and in December; and continuing volcanogenic seismic swarms at Shishaldin Volcano throughout the year. Instrumentation and data acquisition highlights in 2002 were the installation of a subnetwork on Okmok Volcano, the establishment of telemetry for the Mount Veniaminof subnetwork, and the change in the data acquisition system to

  4. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 2000 through December 31, 2001

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Moran, Seth C.; Paskievitch, John; McNutt, Stephen R.

    2002-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog reflects the status and evolution of the seismic monitoring program, and presents the basic seismic data for the time period January 1, 2000, through December 31, 2001. For an interpretation of these data and previously recorded data, the reader should refer to several recent articles on volcano related seismicity on Alaskan volcanoes in Appendix G. The AVO seismic network was used to monitor twenty-three volcanoes in real time in 2000-2001. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). AVO located 1551 and 1428 earthquakes in 2000 and 2001, respectively, on and around these volcanoes. Highlights of the catalog period (Table 1) include: volcanogenic seismic swarms at Shishaldin Volcano between January and February 2000 and between May and June 2000; an eruption at Mount Cleveland between February and May 2001; episodes of possible tremor at Makushin Volcano starting March 2001 and continuing through 2001, and two earthquake swarms at Great Sitkin Volcano in 2001. This catalog includes: (1) earthquake origin

  5. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1, 2000 through December 31, 2001

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; Moran, Seth C.; Paskievitch, John; McNutt, Stephen R.

    2002-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at potentially active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001). The primary objectives of this program are the seismic surveillance of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog reflects the status and evolution of the seismic monitoring program, and presents the basic seismic data for the time period January 1, 2000, through December 31, 2001. For an interpretation of these data and previously recorded data, the reader should refer to several recent articles on volcano related seismicity on Alaskan volcanoes in Appendix G.The AVO seismic network was used to monitor twenty-three volcanoes in real time in 2000-2001. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). AVO located 1551 and 1428 earthquakes in 2000 and 2001, respectively, on and around these volcanoes.Highlights of the catalog period (Table 1) include: volcanogenic seismic swarms at Shishaldin Volcano between January and February 2000 and between May and June 2000; an eruption at Mount Cleveland between February and May 2001; episodes of possible tremor at Makushin Volcano starting March 2001 and continuing through 2001, and two earthquake swarms at Great Sitkin Volcano in 2001.This catalog includes: (1) earthquake origin times

  6. STUDY OF TRANSPORTATION OF GTL PRODUCTS FROM ALASKAN NORTH SLOPE (ANS) TO MARKETS

    SciTech Connect

    Godwin A. Chukwu, Ph.D., P.E.

    2002-09-01

    The Alaskan North Slope is one of the largest hydrocarbon reserves in the US where Gas-to-Liquids (GTL) technology can be successfully implemented. The proven and recoverable reserves of conventional natural gas in the developed and undeveloped fields in the Alaskan North Slope (ANS) are estimated to be 38 trillion standard cubic feet (TCF) and estimates of additional undiscovered gas reserves in the Arctic field range from 64 TCF to 142 TCF. Transportation of the natural gas from the remote ANS is the key issue in effective utilization of this valuable and abundance resource. The throughput of oil through the Trans Alaska Pipeline System (TAPS) has been on decline and is expected to continue to decline in future. It is projected that by the year 2015, ANS crude oil production will decline to such a level that there will be a critical need for pumping additional liquid from GTL process to provide an adequate volume for economic operation of TAPS. The pumping of GTL products through TAPS will significantly increase its economic life. Transporting GTL products from the North Slope of Alaska down to the Marine terminal at Valdez is no doubt the great challenge facing the Gas to Liquids options of utilizing the abundant natural gas resource of the North Slope. The primary purpose of this study was to evaluate and assess the economic feasibility of transporting GTL products through the TAPS. Material testing program for GTL and GTL/Crude oil blends was designed and implemented for measurement of physical properties of GTL products. The measurement and evaluation of the properties of these materials were necessary so as to access the feasibility of transporting such materials through TAPS under cold arctic conditions. Results of the tests indicated a trend of increasing yield strength with increasing wax content. GTL samples exhibited high gel strengths at temperatures as high as 20 F, which makes it difficult for cold restart following winter shutdowns. Simplified

  7. On the Frontline: Tracking Ocean Acidification in an Alaskan Shellfish Hatchery.

    PubMed

    Evans, Wiley; Mathis, Jeremy T; Ramsay, Jacqueline; Hetrick, Jeff

    2015-01-01

    The invasion of anthropogenic carbon dioxide (CO2) into the ocean is shifting the marine carbonate system such that saturation states of calcium carbonate (CaCO3) minerals are decreasing, and this is having a detrimental impact on early life stages of select shellfish species. The global, secular decrease in CaCO3 saturation states is occurring on top of a backdrop of large natural variability in coastal settings; progressively shifting the envelope of variability and leading to longer and more frequent exposure to adverse conditions. This is a great concern in the State of Alaska, a high-latitude setting vulnerable to rapid changes in the marine carbonate system, where an emerging shellfish industry plans major growth over the coming decades. Currently, the Alutiiq Pride Shellfish Hatchery (APSH) in Seward, Alaska is the only hatchery in the state, and produces many shellfish species with early life stages known to be sensitive to low CaCO3 saturation states. Here we present the first land-based OA measurements made in an Alaskan shellfish hatchery, and detail the trends in the saturation state of aragonite (Ωarag), the more soluble form of CaCO3, over a 10-month period in the APSH seawater supply. These data indicate the largest changes are on the seasonal time scale, with extended periods of sub-optimal Ωarag levels (Ωarag < 1.5) in winter and autumn associated with elevated water column respiration and short-lived runoff events, respectively. The data pinpoint a 5-month window of reprieve with favorable Ωarag conditions above the sub-optimal Ωarag threshold, which under predicted upper-bound CO2 emissions trajectories is estimated to close by 2040. To date, many species in production at APSH remain untested in their response to OA, and the data presented here establish the current conditions at APSH as well as provide a framework for hatchery-based measurements in Alaska. The current and expected conditions seen at APSH are essential to consider for this

  8. On the Frontline: Tracking Ocean Acidification in an Alaskan Shellfish Hatchery

    PubMed Central

    Evans, Wiley; Mathis, Jeremy T.; Ramsay, Jacqueline; Hetrick, Jeff

    2015-01-01

    The invasion of anthropogenic carbon dioxide (CO2) into the ocean is shifting the marine carbonate system such that saturation states of calcium carbonate (CaCO3) minerals are decreasing, and this is having a detrimental impact on early life stages of select shellfish species. The global, secular decrease in CaCO3 saturation states is occurring on top of a backdrop of large natural variability in coastal settings; progressively shifting the envelope of variability and leading to longer and more frequent exposure to adverse conditions. This is a great concern in the State of Alaska, a high-latitude setting vulnerable to rapid changes in the marine carbonate system, where an emerging shellfish industry plans major growth over the coming decades. Currently, the Alutiiq Pride Shellfish Hatchery (APSH) in Seward, Alaska is the only hatchery in the state, and produces many shellfish species with early life stages known to be sensitive to low CaCO3 saturation states. Here we present the first land-based OA measurements made in an Alaskan shellfish hatchery, and detail the trends in the saturation state of aragonite (Ωarag), the more soluble form of CaCO3, over a 10-month period in the APSH seawater supply. These data indicate the largest changes are on the seasonal time scale, with extended periods of sub-optimal Ωarag levels (Ωarag < 1.5) in winter and autumn associated with elevated water column respiration and short-lived runoff events, respectively. The data pinpoint a 5-month window of reprieve with favorable Ωarag conditions above the sub-optimal Ωarag threshold, which under predicted upper-bound CO2 emissions trajectories is estimated to close by 2040. To date, many species in production at APSH remain untested in their response to OA, and the data presented here establish the current conditions at APSH as well as provide a framework for hatchery-based measurements in Alaska. The current and expected conditions seen at APSH are essential to consider for this

  9. Investigating Alaskan methane and carbon dioxide fluxes using measurements from the CARVE tower

    NASA Astrophysics Data System (ADS)

    Karion, Anna; Sweeney, Colm; Miller, John B.; Andrews, Arlyn E.; Commane, Roisin; Dinardo, Steven; Henderson, John M.; Lindaas, Jacob; Lin, John C.; Luus, Kristina A.; Newberger, Tim; Tans, Pieter; Wofsy, Steven C.; Wolter, Sonja; Miller, Charles E.

    2016-04-01

    Northern high-latitude carbon sources and sinks, including those resulting from degrading permafrost, are thought to be sensitive to the rapidly warming climate. Because the near-surface atmosphere integrates surface fluxes over large ( ˜ 500-1000 km) scales, atmospheric monitoring of carbon dioxide (CO2) and methane (CH4) mole fractions in the daytime mixed layer is a promising method for detecting change in the carbon cycle throughout boreal Alaska. Here we use CO2 and CH4 measurements from a NOAA tower 17 km north of Fairbanks, AK, established as part of NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), to investigate regional fluxes of CO2 and CH4 for 2012-2014. CARVE was designed to use aircraft and surface observations to better understand and quantify the sensitivity of Alaskan carbon fluxes to climate variability. We use high-resolution meteorological fields from the Polar Weather Research and Forecasting (WRF) model coupled with the Stochastic Time-Inverted Lagrangian Transport model (hereafter, WRF-STILT), along with the Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM), to investigate fluxes of CO2 in boreal Alaska using the tower observations, which are sensitive to large areas of central Alaska. We show that simulated PolarVPRM-WRF-STILT CO2 mole fractions show remarkably good agreement with tower observations, suggesting that the WRF-STILT model represents the meteorology of the region quite well, and that the PolarVPRM flux magnitudes and spatial distribution are generally consistent with CO2 mole fractions observed at the CARVE tower. One exception to this good agreement is that during the fall of all 3 years, PolarVPRM cannot reproduce the observed CO2 respiration. Using the WRF-STILT model, we find that average CH4 fluxes in boreal Alaska are somewhat lower than flux estimates by Chang et al. (2014) over all of Alaska for May-September 2012; we also find that enhancements appear to persist during some wintertime

  10. Investigating Alaskan methane and carbon dioxide fluxes using measurements from the CARVE tower

    NASA Astrophysics Data System (ADS)

    Karion, A.; Sweeney, C.; Miller, J. B.; Andrews, A. E.; Commane, R.; Dinardo, S.; Henderson, J. M.; Lindaas, J.; Lin, J. C.; Luus, K. A.; Newberger, T.; Tans, P.; Wofsy, S. C.; Wolter, S.; Miller, C. E.

    2015-12-01

    Northern high-latitude carbon sources and sinks, including those resulting from degrading permafrost, are thought to be sensitive to the rapidly warming climate. Because the near-surface atmosphere integrates surface fluxes over large (~ 500-1000 km) scales, atmospheric monitoring of carbon dioxide (CO2) and methane (CH4) mole fractions in the daytime mixed layer is a promising method for detecting change in the carbon cycle throughout boreal Alaska. Here we use CO2 and CH4 measurements from a NOAA tower 17 km north of Fairbanks AK, established as part of NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), to investigate regional fluxes of CO2 and CH4 for 2012-2014. CARVE was designed to use aircraft and surface observations to better understand and quantify the sensitivity of Alaskan carbon fluxes to climate variability. We use high-resolution meteorological fields from the Polar Weather Research and Forecasting (WRF) model coupled with the Stochastic Time-Inverted Lagrangian Transport model (hereafter, WRF-STILT), along with the Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM), to investigate fluxes of CO2 in boreal Alaska using the tower observations, which are sensitive to large areas of central Alaska. We show that simulated PolarVPRM/WRF-STILT CO2 mole fractions show remarkably good agreement with tower observations, suggesting that the WRF-STILT model represents the meteorology of the region quite well, and that the PolarVPRM flux magnitudes and spatial distribution are consistent with CO2 mole fractions observed at the CARVE tower. CO2 signals at the tower are larger than predicted, with significant respiration occurring in the fall that is not captured by PolarVPRM. Using the WRF-STILT model, we find that average CH4 fluxes in boreal Alaska are somewhat lower than flux estimates by Chang et al. (2014) over all of Alaska for May-September 2012; we also find emissions persist during some wintertime periods, augmenting those

  11. Thunderstorms Increase Mercury Wet Deposition.

    PubMed

    Holmes, Christopher D; Krishnamurthy, Nishanth P; Caffrey, Jane M; Landing, William M; Edgerton, Eric S; Knapp, Kenneth R; Nair, Udaysankar S

    2016-09-01

    Mercury (Hg) wet deposition, transfer from the atmosphere to Earth's surface by precipitation, in the United States is highest in locations and seasons with frequent deep convective thunderstorms, but it has never been demonstrated whether the connection is causal or simple coincidence. We use rainwater samples from over 800 individual precipitation events to show that thunderstorms increase Hg concentrations by 50% relative to weak convective or stratiform events of equal precipitation depth. Radar and satellite observations reveal that strong convection reaching the upper troposphere (where high atmospheric concentrations of soluble, oxidized mercury species (Hg(II)) are known to reside) produces the highest Hg concentrations in rain. As a result, precipitation meteorology, especially thunderstorm frequency and total rainfall, explains differences in Hg deposition between study sites located in the eastern United States. Assessing the fate of atmospheric mercury thus requires bridging the scales of global transport and convective precipitation. PMID:27464305

  12. Wet comet model: Rosetta redux

    NASA Astrophysics Data System (ADS)

    Sheldon, Robert B.

    2015-09-01

    The wet-comet model (WCM) of the structure and composition of comets was developed in 2005 to replace the "dirty-snowball" model (DSM) of Fred Whipple, because the first comet flybys of P/Halley "armada" revealed a very different landscape. Subsequent flybys of P/Borrelly, P/Wild-2, P/Hartley, P/Tempel-1 have confirmed and refined the model, so that we confidently predicted that the Rosetta mission would encounter a prolate, tumbling, concrete-encrusted, black comet: P/Churyumov-Gerasimenko. Unfortunately, the Philae lander team was preparing for a DSM and the anchors bounced off the concrete surface, but the orbiter has returned spec- tacular pictures of every crevice, which confirm and extend the WCM yet a sixth time. We report of what we predicted, what was observed, and several unexpected results from the ROSETTA mission.

  13. Thunderstorms Increase Mercury Wet Deposition.

    PubMed

    Holmes, Christopher D; Krishnamurthy, Nishanth P; Caffrey, Jane M; Landing, William M; Edgerton, Eric S; Knapp, Kenneth R; Nair, Udaysankar S

    2016-09-01

    Mercury (Hg) wet deposition, transfer from the atmosphere to Earth's surface by precipitation, in the United States is highest in locations and seasons with frequent deep convective thunderstorms, but it has never been demonstrated whether the connection is causal or simple coincidence. We use rainwater samples from over 800 individual precipitation events to show that thunderstorms increase Hg concentrations by 50% relative to weak convective or stratiform events of equal precipitation depth. Radar and satellite observations reveal that strong convection reaching the upper troposphere (where high atmospheric concentrations of soluble, oxidized mercury species (Hg(II)) are known to reside) produces the highest Hg concentrations in rain. As a result, precipitation meteorology, especially thunderstorm frequency and total rainfall, explains differences in Hg deposition between study sites located in the eastern United States. Assessing the fate of atmospheric mercury thus requires bridging the scales of global transport and convective precipitation.

  14. Contrasting support for alternative models of genomic variation based on microhabitat preference: species-specific effects of climate change in alpine sedges.

    PubMed

    Massatti, Rob; Knowles, L Lacey

    2016-08-01

    Deterministic processes may uniquely affect codistributed species' phylogeographic patterns such that discordant genetic variation among taxa is predicted. Yet, explicitly testing expectations of genomic discordance in a statistical framework remains challenging. Here, we construct spatially and temporally dynamic models to investigate the hypothesized effect of microhabitat preferences on the permeability of glaciated regions to gene flow in two closely related montane species. Utilizing environmental niche models from the Last Glacial Maximum and the present to inform demographic models of changes in habitat suitability over time, we evaluate the relative probabilities of two alternative models using approximate Bayesian computation (ABC) in which glaciated regions are either (i) permeable or (ii) a barrier to gene flow. Results based on the fit of the empirical data to data sets simulated using a spatially explicit coalescent under alternative models indicate that genomic data are consistent with predictions about the hypothesized role of microhabitat in generating discordant patterns of genetic variation among the taxa. Specifically, a model in which glaciated areas acted as a barrier was much more probable based on patterns of genomic variation in Carex nova, a wet-adapted species. However, in the dry-adapted Carex chalciolepis, the permeable model was more probable, although the difference in the support of the models was small. This work highlights how statistical inferences can be used to distinguish deterministic processes that are expected to result in discordant genomic patterns among species, including species-specific responses to climate change.

  15. Contrasting support for alternative models of genomic variation based on microhabitat preference: species-specific effects of climate change in alpine sedges.

    PubMed

    Massatti, Rob; Knowles, L Lacey

    2016-08-01

    Deterministic processes may uniquely affect codistributed species' phylogeographic patterns such that discordant genetic variation among taxa is predicted. Yet, explicitly testing expectations of genomic discordance in a statistical framework remains challenging. Here, we construct spatially and temporally dynamic models to investigate the hypothesized effect of microhabitat preferences on the permeability of glaciated regions to gene flow in two closely related montane species. Utilizing environmental niche models from the Last Glacial Maximum and the present to inform demographic models of changes in habitat suitability over time, we evaluate the relative probabilities of two alternative models using approximate Bayesian computation (ABC) in which glaciated regions are either (i) permeable or (ii) a barrier to gene flow. Results based on the fit of the empirical data to data sets simulated using a spatially explicit coalescent under alternative models indicate that genomic data are consistent with predictions about the hypothesized role of microhabitat in generating discordant patterns of genetic variation among the taxa. Specifically, a model in which glaciated areas acted as a barrier was much more probable based on patterns of genomic variation in Carex nova, a wet-adapted species. However, in the dry-adapted Carex chalciolepis, the permeable model was more probable, although the difference in the support of the models was small. This work highlights how statistical inferences can be used to distinguish deterministic processes that are expected to result in discordant genomic patterns among species, including species-specific responses to climate change. PMID:27317885

  16. A cold and wet Mars

    NASA Astrophysics Data System (ADS)

    Fairén, Alberto G.

    2010-07-01

    Water on Mars has been explained by invoking controversial and mutually exclusive solutions based on warming the atmosphere with greenhouse gases (the "warm and wet" Mars) or on local thermal energy sources acting in a global freezing climate (the "cold and dry" Mars). Both have critical limitations and none has been definitively accepted as a compelling explanation for the presence of liquid water on Mars. Here is considered the hypothesis that cold, saline and acidic liquid solutions have been stable on the sub-zero surface of Mars for relatively extended periods of time, completing a hydrogeological cycle in a water-enriched but cold planet. Computer simulations have been developed to analyze the evaporation processes of a hypothetical martian fluid with a composition resulting from the acid weathering of basalt. This model is based on orbiter- and lander-observed surface mineralogy of Mars, and is consistent with the sequence and time of deposition of the different mineralogical units. The hydrological cycle would have been active only in periods of dense atmosphere, as having a minimum atmospheric pressure is essential for water to flow, and relatively high temperatures (over ˜245 K) are required to trigger evaporation and snowfall; minor episodes of limited liquid water on the surface could have occurred at lower temperatures (over ˜225 K). During times with a thin atmosphere and even lesser temperatures (under ˜225 K), only transient liquid water can potentially exist on most of the martian surface. Assuming that surface temperatures have always been maintained below 273 K, Mars can be considered a "cold and wet" planet for a substantial part of its geological history.

  17. Impact of the Alaskan Stream flow on surface water dynamics, temperature, ice extent, plankton biomass, and walleye pollock stocks in the eastern Okhotsk Sea

    NASA Astrophysics Data System (ADS)

    Prants, S. V.; Andreev, A. G.; Budyansky, M. V.; Uleysky, M. Yu.

    2015-11-01

    Year-to-year changes of the Alaskan Stream surface flow, forming the northern boundary of the western subarctic cyclonic gyre in the Pacific, impact the dynamics of water in the eastern Okhotsk Sea. It is shown by Lagrangian simulation of transport of the Alaskan Stream waters in 20 year-long AVISO velocity field and direct computation of the corresponding fluxes that an intensification/weakening of the Alaskan Stream current leads to increased/decreased northward fluxes in the areas of the Krusenstern and Fourth Kuril straits connected the Okhotsk Sea with the Pacific Ocean. Enhancement of the Alaskan Stream flux is accompanied by an increase in water temperature and decreasing ice area in the Okhotsk Sea in winter. The Alaskan Stream surface flux is shown to be negatively correlated with satellite-derived chlorophyll-a concentration in May from r = - 0.68 to - 0.73 in 1998-2013 and with winter-spring biomass of large-sized zooplankton with r = - 0.70 in 1995-2012. It is positively correlated with winter-spring biomass of small- and medium-sized zooplankton in the eastern Okhotsk Sea with r = 0.74 in 1995-2012.

  18. Constraining the 2012-2014 growing season Alaskan methane budget using CARVE aircraft measurements

    NASA Astrophysics Data System (ADS)

    Hartery, S.; Chang, R. Y. W.; Commane, R.; Lindaas, J.; Miller, S. M.; Wofsy, S. C.; Karion, A.; Sweeney, C.; Miller, C. E.; Dinardo, S. J.; Steiner, N.; McDonald, K. C.; Watts, J. D.; Zona, D.; Oechel, W. C.; Kimball, J. S.; Henderson, J.; Mountain, M. E.

    2015-12-01

    Soil in northen latitudes contains rich carbon stores which have been historically preserved via permafrost within the soil bed; however, recent surface warming in these regions is allowing deeper soil layers to thaw, influencing the net carbon exchange from these areas. Due to the extreme nature of its climate, these eco-regions remain poorly understood by most global models. In this study we analyze methane fluxes from Alaska using in situ aircraft observations from the 2012-2014 Carbon in Arctic Reservoir Vulnerability Experiment (CARVE). These observations are coupled with an atmospheric particle transport model which quantitatively links surface emissions to atmospheric observations to make regional methane emission estimates. The results of this study are two-fold. First, the inter-annual variability of the methane emissions was found to be <1 Tg over the area of interest and is largely influenced by the length of time the deep soil remains unfrozen. Second, the resulting methane flux estimates and mean soil parameters were used to develop an empirical emissions model to help spatially and temporally constrain the methane exchange at the Alaskan soil surface. The empirical emissions model will provide a basis for exploring the sensitivity of methane emissions to subsurface soil temperature, soil moisture, organic carbon content, and other parameters commonly used in process-based models.

  19. Geographic patterns and dynamics of Alaskan climate interpolated from a sparse station record

    USGS Publications Warehouse

    Fleming, Michael D.; Chapin, F. Stuart; Cramer, W.; Hufford, Gary L.; Serreze, M.C.

    2000-01-01

    Data from a sparse network of climate stations in Alaska were interpolated to provide 1-km resolution maps of mean monthly temperature and precipitation-variables that are required at high spatial resolution for input into regional models of ecological processes and resource management. The interpolation model is based on thin-plate smoothing splines, which uses the spatial data along with a digital elevation model to incorporate local topography. The model provides maps that are consistent with regional climatology and with patterns recognized by experienced weather forecasters. The broad patterns of Alaskan climate are well represented and include latitudinal and altitudinal trends in temperature and precipitation and gradients in continentality. Variations within these broad patterns reflect both the weakening and reduction in frequency of low-pressure centres in their eastward movement across southern Alaska during the summer, and the shift of the storm tracks into central and northern Alaska in late summer. Not surprisingly, apparent artifacts of the interpolated climate occur primarily in regions with few or no stations. The interpolation model did not accurately represent low-level winter temperature inversions that occur within large valleys and basins. Along with well-recognized climate patterns, the model captures local topographic effects that would not be depicted using standard interpolation techniques. This suggests that similar procedures could be used to generate high-resolution maps for other high-latitude regions with a sparse density of data.

  20. Alaskan Wild Berry Resources and Human Health Under the Cloud of Climate Change

    PubMed Central

    KELLOGG, JOSHUA; WANG, JINZHI; FLINT, COURTNEY; RIBNICKY, DAVID; KUHN, PETER; DE MEJIA, ELVIRA GONZÁLEZ; RASKIN, ILYA; LILA, MARY ANN

    2009-01-01

    Wild berries are integral dietary components for Alaska Native tribes and a rich source of polyphenolic metabolites that can ameliorate metabolic disorders such as obesity and diabetes. In this study, five species of wild Alaskan berries (Vaccinium ovalifolium, V. uliginosum, Rubus chamaemorus, R. spectabilis, and Empetrum nigrum) were screened for bioactivity through a community-participatory research method involving three geographically-distinct tribal communities. Compositional analysis by HPLC and LC-MS2 revealed substantial site-specific variation in anthocyanins (0.01-4.39 mg/g-FW) and proanthocyanidins (0.74-6.25 mg/g-FW), and identified A-type proanthocyanidin polymers. R. spectabilis increased expression levels of preadipocyte-factor-1 (182%), and proanthocyanidin-enriched fractions from other species reduced lipid accumulation in 3T3-L1 adipocytes. Selected extracts reduced serum glucose levels in C57bl/6j mice by up to 45%. Local observations provided robust insights into effects of climatic fluctuations on berry abundance and quality, and preliminary site-specific compositional and bioactivity differences were noted, suggesting the need to monitor this Alaska Native resource as climate shifts impact the region. PMID:20025229

  1. InSAR detects possible thaw settlement in the Alaskan Arctic Coastal Plain

    USGS Publications Warehouse

    Rykhus, R.P.; Lu, Zhiming

    2008-01-01

    Satellite interferometric synthetic aperture radar (InSAR) has proven to be an effective tool for monitoring surface deformation from volcanoes, earthquakes, landslides, and groundwater withdrawal. This paper seeks to expand the list of applications of InSAR data to include monitoring subsidence possibly associated with thaw settlement over the Alaskan Arctic Coastal Plain. To test our hypothesis that InSAR data are sufficiently sensitive to detect subsidence associated with thaw settlement, we acquired all Japanese Earth Resources Satellite-1 (JERS-1) L-band data available for the summers of 1996, 1997, and 1998 over two sites on the Alaska North Slope. The least amount of subsidence for both study sites was detected in the interferograms covering the summer of 1996 (2-3 cm), interferograms from 1997 and 1998 revealed that about 3 cm of subsidence occurred at the northern Cache One Lake site, and about 5 cm of subsidence was detected at the southern Kaparuk River site. These preliminary results illustrate the capacity of the L-band (24 cm) wavelength JERS-1 radar data to penetrate the short Arctic vegetation to monitor subsidence possibly associated with thaw settlement of the active layer and (or) other hydrologic changes over relatively large areas. ?? 2008 CASI.

  2. Hepatitis C Virus in American Indian/Alaskan Native and Aboriginal Peoples of North America

    PubMed Central

    Rempel, Julia D.; Uhanova, Julia

    2012-01-01

    Liver diseases, such as hepatitis C virus (HCV), are “broken spirit” diseases. The prevalence of HCV infection for American Indian/Alaskan Native (AI/AN) in the United States and Canadian Aboriginals varies; nonetheless, incidence rates of newly diagnosed HCV infection are typically higher relative to non-indigenous people. For AI/AN and Aboriginal peoples risk factors for the diagnosis of HCV can reflect that of the general population: predominately male, a history of injection drug use, in midlife years, with a connection with urban centers. However, the face of the indigenous HCV infected individual is becoming increasingly female and younger compared to non-indigenous counterparts. Epidemiology studies indicate that more effective clearance of acute HCV infection can occur for select Aboriginal populations, a phenomenon which may be linked to unique immune characteristics. For individuals progressing to chronic HCV infection treatment outcomes are comparable to other racial cohorts. Disease progression, however, is propelled by elevated rates of co-morbidities including type 2 diabetes and alcohol use, along with human immunodeficiency virus (HIV) co-infection relative to non-indigenous patients. Historical and personal trauma has a major role in the participation of high risk behaviors and associated diseases. Although emerging treatments provide hope, combating HCV related morbidity and mortality will require interventions that address the etiology of broken spirit diseases. PMID:23342378

  3. Effects of simultaneous climate change and geomorphic evolution on thermal characteristics of a shallow Alaskan lake

    USGS Publications Warehouse

    Griffiths, J.R.; Schindler, D.E.; Balistrieri, L.S.; Ruggerone, G.T.

    2011-01-01

    We used a hydrodynamics model to assess the consequences of climate warming and contemporary geomorphic evolution for thermal conditions in a large, shallow Alaskan lake. We evaluated the effects of both known climate and landscape change, including rapid outlet erosion and migration of the principal inlet stream, over the past 50 yr as well as future scenarios of geomorphic restoration. Compared to effects of air temperature during the past 50 yr, lake thermal properties showed little sensitivity to substantial (, 60%) loss of lake volume, as the lake maximum depth declined from 6 m to 4 m driven by outlet erosion. The direction and magnitude of future lake thermal responses will be driven largely by the extent of inlet stream migration when it occurs simultaneously with outlet erosion. Maintaining connectivity with inlet streams had substantial effects on buffering lake thermal responses to warming climate. Failing to account for changing rates and types of geomorphic processes under continuing climate change may misidentify the primary drivers of lake thermal responses and reduce our ability to understand the consequences for aquatic organisms. ?? 2011, by the American Society of Limnology and Oceanography, Inc.

  4. Seasonal variation of a snow algal community on an Alaskan glacier

    NASA Astrophysics Data System (ADS)

    Takeuchi, N.

    2003-12-01

    There are cold tolerant algae (snow algae) growing on the surface of glaciers. Several species of snow algae have been reported on Alaskan glaciers. Seasonal variation of the snow algal community was investigated on Gulkana Glacier in the Alaska Range from May to September, 2001. Chlorophyll, nutrients, and stable isotope for carbon and nitrogen (particulate organic matter) were also measured. The snow algal community on this glacier varied with time, in particular changed with snow melting and nutrients in the snow. When the glacier is covered with snow (May), the algal community consisted of mainly only one species of alga (Chlamydomonas nivalis, alga of red snow). The algal biomass and chlorophyll concentration increased with snow melting in early summer. When the glacial ice surface appeared, the community structure changed drastically. The community on the ice consisted of some of different species. The community structure and biomass kept almost constant after the ice surface appeared. Nutrients measurements showed that nitrogen was likely limited on the algal growth rather than phosphate. Especially, the nitrate was depleted from August to September. Results of stable isotope measurements also support the nitrogen limitation of the snow algae in late summer.

  5. Re-analysis of Alaskan benchmark glacier mass-balance data using the index method

    USGS Publications Warehouse

    Van Beusekom, Ashely E.; O'Nell, Shad R.; March, Rod S.; Sass, Louis C.; Cox, Leif H.

    2010-01-01

    At Gulkana and Wolverine Glaciers, designated the Alaskan benchmark glaciers, we re-analyzed and re-computed the mass balance time series from 1966 to 2009 to accomplish our goal of making more robust time series. Each glacier's data record was analyzed with the same methods. For surface processes, we estimated missing information with an improved degree-day model. Degree-day models predict ablation from the sum of daily mean temperatures and an empirical degree-day factor. We modernized the traditional degree-day model and derived new degree-day factors in an effort to match the balance time series more closely. We estimated missing yearly-site data with a new balance gradient method. These efforts showed that an additional step needed to be taken at Wolverine Glacier to adjust for non-representative index sites. As with the previously calculated mass balances, the re-analyzed balances showed a continuing trend of mass loss. We noted that the time series, and thus our estimate of the cumulative mass loss over the period of record, was very sensitive to the data input, and suggest the need to add data-collection sites and modernize our weather stations.

  6. Cost-Optimal Pathways to 75% Fuel Reduction in Remote Alaskan Villages: Preprint

    SciTech Connect

    Simpkins, Travis; Cutler, Dylan; Hirsch, Brian; Olis, Dan; Anderson, Kate

    2015-10-28

    There are thousands of isolated, diesel-powered microgrids that deliver energy to remote communities around the world at very high energy costs. The Remote Communities Renewable Energy program aims to help these communities reduce their fuel consumption and lower their energy costs through the use of high penetration renewable energy. As part of this program, the REopt modeling platform for energy system integration and optimization was used to analyze cost-optimal pathways toward achieving a combined 75% reduction in diesel fuel and fuel oil consumption in a select Alaskan village. In addition to the existing diesel generator and fuel oil heating technologies, the model was able to select from among wind, battery storage, and dispatchable electric heaters to meet the electrical and thermal loads. The model results indicate that while 75% fuel reduction appears to be technically feasible it may not be economically viable at this time. When the fuel reduction target was relaxed, the results indicate that by installing high-penetration renewable energy, the community could lower their energy costs by 21% while still reducing their fuel consumption by 54%.

  7. Recent acceleration of biomass burning and carbon losses in Alaskan forests and peatlands

    USGS Publications Warehouse

    Turetsky, M.R.; Kane, E.S.; Harden, J.W.; Ottmar, R.D.; Manies, K.L.; Hoy, E.; Kasischke, E.S.

    2011-01-01

    Climate change has increased the area affected by forest fires each year in boreal North America. Increases in burned area and fire frequency are expected to stimulate boreal carbon losses. However, the impact of wildfires on carbon emissions is also affected by the severity of burning. How climate change influences the severity of biomass burning has proved difficult to assess. Here, we examined the depth of ground-layer combustion in 178 sites dominated by black spruce in Alaska, using data collected from 31 fire events between 1983 and 2005. We show that the depth of burning increased as the fire season progressed when the annual area burned was small. However, deep burning occurred throughout the fire season when the annual area burned was large. Depth of burning increased late in the fire season in upland forests, but not in peatland and permafrost sites. Simulations of wildfire-induced carbon losses from Alaskan black spruce stands over the past 60 years suggest that ground-layer combustion has accelerated regional carbon losses over the past decade, owing to increases in burn area and late-season burning. As a result, soils in these black spruce stands have become a net source of carbon to the atmosphere, with carbon emissions far exceeding decadal uptake.

  8. Establishment of a New, Cooperative ARM and AmeriFlux Site on the Alaskan North Slope

    NASA Astrophysics Data System (ADS)

    Billesbach, D. P.; Fischer, M. L.; Cook, D. R.; Torn, M. S.; Castanha, C.

    2011-12-01

    We report here on the establishment of a new research facility on the Alaskan North Slope. The experiment, located near Barrow, AK will be operated by the US Department of Energy (US DOE) as a permanent facility at the North Slope of Alaska (NSA) site of the Atmospheric Radiation Measurement (ARM) Climate Research Facility. The instrumentation at the site as well as on-going vegetation and soil measurements will also constitute the core data set for a new AmeriFlux site. Data will be made available through both the ARM and the AmeriFlux data centers. The experiment will be centered around an eddy covariance flux tower that will generated measurements of carbon dioxide, methane, water vapor, and energy fluxes. Additionally, surface radiation, meteorological, and soil instruments will provide ancillary data needed for gap filling, quality control, and climate quantification. Destructive and non-destructive sampling, according to the AmeriFlux biometric sampling protocols will quantify plant biomass, species, leaf area and nitrogen, and soil carbon stocks. Our goal is to assess both the impact that the Arctic costal region might have on the carbon cycle as well as climatic feedbacks that could affect this vulnerable ecosystem.

  9. Depth and temperature of permafrost on the Alaskan Arctic Slope; preliminary results

    USGS Publications Warehouse

    Lachenbruch, Arthur H.; Sass, J.H.; Lawver, L.A.; Brewer, M.C.; Moses, T.H.

    1982-01-01

    As permafrost is defined by its temperature, the only way to determine its depth is to monitor the return to equilibrium of temperatures in boreholes that penetrate permafrost. Such measurements are under way in 25 wells on the Alaskan Arctic Slope; 21 are in Naval Petroleum Reserve Alaska (NPRA), and 4 are in the foothills to the east. Near-equilibrium results indicate that permafrost thickness in NPRA generally ranges between 200 and 400 m (compared to 600+ m at Prudhoe Bay); there are large local variations and no conspicuous regional trends. By contrast the long-term mean temperature of the ground surface (one factor determining permafrost depth) varies systematically from north to south in a pattern modified by the regional topography. The observed variation in permafrost temperature and depth cannot result primarily from effects of surface bodies of water or regional variations in heat flow; they are consistent, however, with expectable variations in the thermal conductivity of the sediments. It remains to be determined (with conductivity measurements) whether certain sites with anomalously high local gradients have anomalously high heat flow; if they do, they might indicate upwelling of interstitial fluids in the underlying basin sediments.

  10. Extent of endocrine disruption in fish of western and Alaskan National Parks

    USGS Publications Warehouse

    Schreck, Carl B.; Kent, Michael

    2013-01-01

    In 2008 2009, 998 fish were collected from 43 water bodies across 11 western Alaskan national parks and analyzed for reproductive abnormalities. Exposure to estrogenic substances such as pesticides can induce abnormalities like intersex. Results suggest there is a greater propensity for male intersex fish collected from parks located in the Rocky Mountains, and specifically in Rocky Mountain NP. Individual male intersex fish were also identified at Lassen Volcanic, Yosemite, and WrangellSt. Elias NPs. The preliminary finding of female intersex was determined to be a false positive. The overall goal of this project was to assess the general health of fish from eleven western national parks to infer whether health impacts may be linked to contaminant health thresholds for animal andor human health. This was accomplished by evaluating the presence of intersex fish with eggs developing in male gonads or sperm developing in female gonads using histology. In addition, endocrine disrupting compounds and other contaminants were quantified in select specimens. General histologic appearance of the gonadal tissue and spleen were observed to assess health.

  11. Possible connection between two Alaskan catastrophes occurring 25 yr apart (1964 and 1989)

    SciTech Connect

    Kvenvolden, K.A.; Carlson, P.R. ); Threlkeld, C.N.; Warden, A. )

    1993-09-01

    On March 24, 1989, the Exxon Valdez supertanker grounded on Bligh Reef, spilling North Slope crude oil into Prince William Sound, Alaska. Tracking the geochemical fate of this spilled oil has revealed, in addition to weathered products from the spill, minor oil residues on beaches from a distinctly different source. By using carbon isotopic compositions of whole-oil residues as a principal method of identification, we found that the [delta][sup +13]C values of Exxon Valdez oil (one sample) and its residues (eight samples from six islands) average [minus]29.3 0.1%. In contrast, the non-Exxon Valdez residues (15 samples from 12 localities) have an average [delta][sup 13]C value of [minus]23.8 [+-]0.1%. This tight distribution of carbon isotopic values suggestes a single event to explain the non-Exxon Valdez residues. This event likely was the Great Alaska Earthquake of March 27, 1964. This quake and the subsequent tsunami destroyed asphalt storage facilities at the old Valdez town site, spilling asphalt ([delta][sup +13]C = [minus]23.6%) into Port Valdez fjord. From there the asphalt apparently advanced south into the sound. Thus, the possible connection between two Alaskan catastrophes, separated by 25 yr, is found in the minor oil-like residues that continue to mark the two events on the beaches of Prince William Sound. 16 refs., 2 figs., 1 tab.

  12. American Indian/Alaskan Native grandparents raising grandchildren: findings from the Census 2000 Supplementary Survey.

    PubMed

    Fuller-Thomson, Esme; Minkler, Meredith

    2005-04-01

    This article documents the prevalence and national profile of American Indian/Alaskan Native (AI/AN) grandparents who are raising their grandchildren, based on data from the American Community Survey/Census 2000 Supplementary Survey. In 2000 there were estimated to be nearly 53,000 AI/AN grandparent caregivers age 45 and older in the United States. Almost half of the caregiving grandparents had been raising a grandchild for five years or longer. The findings reveal a portrait of grandparents committed to raising their grandchildren despite the fact that many were living in extreme poverty, with ill health, and with limited resources and services. One-third of grandparent caregivers were living below the poverty line, and only one-quarter of these were receiving public assistance. Even when compared with their noncaregiving AI/AN peers, grandparents raising grandchildren were disproportionately female, poor, living with a functional disability, and living in overcrowded conditions. Implications for social work practice are presented and recommendations for policy and research are discussed. PMID:15853190

  13. Microbial activity in Alaskan taiga soils contaminated by crude oil in 1976

    SciTech Connect

    Monroe, E.M.; Lindstrom, J.E.; Brown, E.J.; Raddock, J.F. |

    1995-12-31

    Biodegradation, often measured via microbial activity, includes destruction of environmental pollutants by living microorganisms and is dependent upon many physical and chemical factors. Effects of mineral nutrients and organic matter on biodegradation of Prudhoe Bay crude oil were investigated at a nineteen-year-old oil spill site in Alaskan taiga. Microcosms of two different soil types from the spill site; one undeveloped soil with forest litter and detritus (O horizon) and one more developed with lower organic content (A horizon), were treated with various nitrogen and phosphorus amendments, and incubated for up to six weeks. Each microcosm was sampled periodically and assayed for hydrocarbon mineralization potential using radiorespirometry, for total carbon dioxide respired using gas chromatography, and for numbers of hydrocarbon-degrading bacteria and heterotrophic bacteria using most probable number counting techniques. Organic matter in the O horizon soil along with combinations of mineral nutrients were found to stimulate microbial activity. No combination of mineral nutrient additions to the A horizon soil stimulated any of the parameters above those measured in control microcosms. The results of this study indicate that adding mineral nutrients and tilling the O horizon into the A horizon of subarctic soils contaminated with crude oil, would stimulate microbial activity, and therefore the biodegradation potential, ultimately increasing the rate of destruction of crude oil in these soils.

  14. Evolution of age and length at maturation of Alaskan salmon under size-selective harvest.

    PubMed

    Kendall, Neala W; Dieckmann, Ulf; Heino, Mikko; Punt, André E; Quinn, Thomas P

    2014-02-01

    Spatial and temporal trends and variation in life-history traits, including age and length at maturation, can be influenced by environmental and anthropogenic processes, including size-selective exploitation. Spawning adults in many wild Alaskan sockeye salmon populations have become shorter at a given age over the past half-century, but their age composition has not changed. These fish have been exploited by a gillnet fishery since the late 1800s that has tended to remove the larger fish. Using a rare, long-term dataset, we estimated probabilistic maturation reaction norms (PMRNs) for males and females in nine populations in two basins and correlated these changes with fishery size selection and intensity to determine whether such selection contributed to microevolutionary changes in maturation length. PMRN midpoints decreased in six of nine populations for both sexes, consistent with the harvest. These results support the hypothesis that environmental changes in the ocean (likely from competition) combined with adaptive microevolution (decreased PMRNs) have produced the observed life-history patterns. PMRNs did not decrease in all populations, and we documented differences in magnitude and consistency of size selection and exploitation rates among populations. Incorporating evolutionary considerations and tracking further changes in life-history traits can support continued sustainable exploitation and productivity in these and other exploited natural resources. PMID:24567750

  15. Upwelling on the continental slope of the Alaskan Beaufort Sea: Storms, ice, and oceanographic response

    NASA Astrophysics Data System (ADS)

    Pickart, Robert S.; Moore, G. W. K.; Torres, Daniel J.; Fratantoni, Paula S.; Goldsmith, Roger A.; Yang, Jiayan

    2009-01-01

    The characteristics of Pacific-born storms that cause upwelling along the Beaufort Sea continental slope, the oceanographic response, and the modulation of the response due to sea ice are investigated. In fall 2002 a mooring array located near 152°W measured 11 significant upwelling events that brought warm and salty Atlantic water to shallow depths. When comparing the storms that caused these events to other Aleutian lows that did not induce upwelling, interesting trends emerged. Upwelling occurred most frequently when storms were located in a region near the eastern end of the Aleutian Island Arc and Alaskan Peninsula. Not only were these storms deep but they generally had northward-tending trajectories. While the steering flow aloft aided this northward progression, the occurrence of lee cyclogenesis due to the orography of Alaska seems to play a role as well in expanding the meridional influence of the storms. In late fall and early winter both the intensity and frequency of the upwelling diminished significantly at the array site. It is argued that the reduction in amplitude was due to the onset of heavy pack ice, while the decreased frequency was due to two different upper-level atmospheric blocking patterns inhibiting the far field influence of the storms.

  16. No evidence of metabolic depression in Western Alaskan juvenile Steller sea lions (Eumetopias jubatus).

    PubMed

    Hoopes, Lisa A; Rea, Lorrie D; Christ, Aaron; Worthy, Graham A J

    2014-01-01

    Steller sea lion (Eumetopias jubatus) populations have undergone precipitous declines through their western Alaskan range over the last four decades with the leading hypothesis to explain this decline centering around changing prey quality, quantity, or availability for this species (i.e., nutritional stress hypothesis). Under chronic conditions of reduced food intake sea lions would conserve energy by limiting energy expenditures through lowering of metabolic rate known as metabolic depression. To examine the potential for nutritional stress, resting metabolic rate (RMR) and body composition were measured in free-ranging juvenile Steller sea lions (N = 91) at three distinct geographical locations (Southeast Alaska, Prince William Sound, Central Aleutian Islands) using open-flow respirometry and deuterium isotope dilution, respectively. Average sea lion RMR ranged from 6.7 to 36.2 MJ d(-1) and was influenced by body mass, total body lipid, and to a lesser extent, ambient air temperature and age. Sea lion pups captured in the Aleutian Islands (region of decline) had significantly greater body mass and total body lipid stores when compared to pups from Prince William Sound (region of decline) and Southeast Alaska (stable region). Along with evidence of robust body condition in Aleutian Island pups, no definitive differences were detected in RMR between sea lions sampled between eastern and western populations that could not be accounted for by higher percent total body lipid content, suggesting that that at the time of this study, Steller sea lions were not experiencing metabolic depression in the locations studied. PMID:24416394

  17. Methane transport mechanisms and isotopic fractionation in emergent macrophytes of an Alaskan tundra lake

    SciTech Connect

    Chanton, J.P.; Martens, C.S.; Kelley, C.A.; Crill, P.M.; Showers, W.J. North Carolina Univ., Chapel Hill New Hampshire Univ., Durham North Carolina State Univ., Raleigh )

    1992-10-01

    The stable carbon isotopic composition of methane associated with and emitted by the two dominant emergent macrophytes abundant in the many Alaskan tundra lakes, Carex rostrata and Arctophila fulva, is determined. The carbon isotopic composition of the methane was -58.6 +/- 0.5 (n=2) for Arctophila and -66.6 +/- 2.5 (n=6) for Carex. The methane emitted by these species is depleted in C-13 by 12 per mil for Arctophila and 18 per mil for Carex relative to methane withdrawn from plant stems 1-2 cm below the waterline. The results suggest more rapid transport of (C-12)H4 relative to (C-13)H4 through plants to the atmosphere. Plant stem methane concentrations ranged from 0.2 to 4.0 percent in Arctophila, with an isotopic composition of -46.1 +/- 4.3 percent (n=8). Carex stem methane concentrations ranged from 150 to 1200 ppm, with an isotopic composition of -48.3 +/- 1.4 per mil (n=3). 60 refs.

  18. Incorporating deep and shallow components of genetic structure into the management of Alaskan red king crab

    PubMed Central

    Grant, William Stewart; Cheng, Wei

    2012-01-01

    Observed patterns of genetic variability among marine populations are shaped not only by contemporary levels of gene flow, but also by divergences during historical isolations. We examined variability at 15 SNP loci and in mtDNA sequences (COI, 665 bp) in red king crab from 17 localities in the North Pacific. These markers define three geographically distinct evolutionary lineages (SNPs, FCT = 0.054; mtDNA ΦCT = 0.222): (i) Okhotsk Sea–Norton Sound–Aleutian Islands, (ii) southeastern Bering Sea–western Gulf of Alaska, and (iii) Southeast Alaska. Populations in the Bering Sea and in Southeast Alaska are genetically heterogeneous, but populations in the center of the range are homogeneous. Mitochondrial DNA diversity drops from h = 0.91 in the northwestern Pacific to h = 0.24 in the Southeast Alaska. Bayesian skyline plots (BSPs) indicate postglacial population expansions, presumably from ice-age refugia. BSPs of sequences simulated under a demographic model defined by late Pleistocene temperatures failed to detect demographic variability before the last glacial maximum. These results sound a note of caution for the interpretation of BSPs. Population fragmentation in the Bering Sea and in Southeast Alaskan waters requires population management on a small geographic scale, and deep evolutionary partitions between the three geographic groups mandate regional conservation measures. PMID:23346227

  19. Chemical and biological assessment of two offshore drilling sites in the Alaskan Arctic.

    PubMed

    Trefry, John H; Dunton, Kenneth H; Trocine, Robert P; Schonberg, Susan V; McTigue, Nathan D; Hersh, Eric S; McDonald, Thomas J

    2013-05-01

    A retrospective chemical and biological study was carried out in Camden Bay, Alaskan Beaufort Sea, where single exploratory oil wells were drilled at two sites more than two decades ago. Barium from discharged drilling mud was present in sediments at concentrations as high as 14%, ~200 times above background, with significantly higher concentrations of Ba, but not other metals, within 250 m of the drilling site versus reference stations. Elevated concentrations of Cr, Cu, Hg and Pb were found only at two stations within 25 m of one drilling site. Concentrations of total polycyclic aromatic hydrocarbons (TPAH) were not significantly different at reference versus drilling-site stations; however, TPAH were elevated in Ba-rich layers from naturally occurring perylene in ancient formation cuttings. Infaunal biomass and species abundance were not significantly different at reference versus drilling-site stations; infauna were less diverse at drilling-site stations. Our assessment showed that discharges from single wells within large areas caused minimal long-term, adverse impacts to the benthic ecosystem.

  20. Estimation of carbon emissions from wildfires in Alaskan boreal forests using AVHRR data

    SciTech Connect

    Kasischke, E.S.; French, N.H.F.; Bourgeau-Chavez, L.L )

    1993-06-01

    The objectives of this research study were to evaluate the utility of using AVHRR data for locating and measuring the areal extent of wildfires in the boreal forests of Alaska and to estimate the amount of carbon being released during these fires. Techniques were developed to using the normalized difference vegetation signature derived from AVHRR data to detect and measure the area of fires in Alaska. A model was developed to estimate the amount of biomass/carbon being stored in Alaskan boreal forests, and the amount of carbon released during fires. The AVHRR analysis resulted in detection of > 83% of all forest fires greater than 2,000 ha in size in the years 1990 and 1991. The areal estimate derived from AVHRR data were 75% of the area mapped by the Alaska Fire Service for these years. Using fire areas and locations for 1954 through 1992, it was determined that on average, 13.0 gm-C-m-2 of boreal forest area is released during fires every year. This estimate is two to six times greater than previous reported estimates. Our conclusions are that the analysis of AVHRR data represents a viable means for detecting and mapping fires in boreal regions on a global basis.

  1. Methane transport mechanisms and isotopic fractionation in emergent macrophytes of an Alaskan tundra lake

    NASA Technical Reports Server (NTRS)

    Chanton, Jeffrey P.; Martens, Christopher S.; Kelley, Cheryl A.; Crill, Patrick M.; Showers, William J.

    1992-01-01

    The stable carbon isotopic composition of methane associated with and emitted by the two dominant emergent macrophytes abundant in the many Alaskan tundra lakes, Carex rostrata and Arctophila fulva, is determined. The carbon isotopic composition of the methane was -58.6 +/- 0.5 (n=2) for Arctophila and -66.6 +/- 2.5 (n=6) for Carex. The methane emitted by these species is depleted in C-13 by 12 per mil for Arctophila and 18 per mil for Carex relative to methane withdrawn from plant stems 1-2 cm below the waterline. The results suggest more rapid transport of (C-12)H4 relative to (C-13)H4 through plants to the atmosphere. Plant stem methane concentrations ranged from 0.2 to 4.0 percent in Arctophila, with an isotopic composition of -46.1 +/- 4.3 percent (n=8). Carex stem methane concentrations ranged from 150 to 1200 ppm, with an isotopic composition of -48.3 +/- 1.4 per mil (n=3).

  2. Possible connection between two Alaskan catastrophes occurring 25 yr apart (1964 and 1989)

    NASA Astrophysics Data System (ADS)

    Kvenvolden, Keith A.; Carlson, Paul R.; Threlkeld, Charles N.; Warden, Augusta

    1993-09-01

    On March 24, 1989, the Exxon Valdez supertanker grounded on Bligh Reef, spilling North Slope crude oil into Prince William Sound, Alaska. Tracking the geochemical fate of this spilled oil has revealed, in addition to weathered products from the spill, minor oil residues on beaches from a distinctly different source. By using carbon isotopic compositions of whole-oil residues as a principal method of identification, we found that the δ13C values of Exxon Valdez oil (one sample) and its residues (eight samples from six islands) average -29.3 ±0.1‰. In contrast, the non-Exxon Valdez residues (15 samples from 12 localities) have an average δ13C value of -23.8 ±0.1‰. This tight distribution of carbon isotopic values suggests a single event to explain the non-Exxon Valdez residues. This event likely was the Great Alaska Earthquake of March 27, 1964. This quake and the subsequent tsunami destroyed asphalt storage facilities at the old Valdez town site, spilling asphalt (δ13C = -23.6‰) into Port Valdez fjord. From there the asphalt apparently advanced south into the sound. Thus, the possible connection between two Alaskan catastrophes, separated by 25 yr, is found in the minor oil- like residues that continue to mark the two events on the beaches of Prince William Sound.

  3. Hepatitis C virus in American Indian/Alaskan Native and Aboriginal peoples of North America.

    PubMed

    Rempel, Julia D; Uhanova, Julia

    2012-12-01

    Liver diseases, such as hepatitis C virus (HCV) infection, are "broken spirit" diseases. The prevalence of HCV infection for American Indian/Alaskan Native (AI/AN) in the United States and Canadian Aboriginals varies; nonetheless, incidence rates of newly diagnosed HCV infection are typically higher relative to non-indigenous people. For AI/AN and Aboriginal peoples risk factors for the diagnosis of HCV infection can reflect that of the general population: predominately male, a history of injection drug use, in midlife years, with a connection with urban centers. However, the face of the indigenous HCV infected individual is becoming increasingly female and younger compared to non-indigenous counterparts. Epidemiology studies indicate that more effective clearance of acute HCV infection can occur for select Aboriginal populations, a phenomenon which may be linked to unique immune characteristics. For individuals progressing to chronic HCV infection treatment outcomes are comparable to other racial cohorts. Disease progression, however, is propelled by elevated rates of co-morbidities including type 2 diabetes and alcohol use, along with human immunodeficiency virus (HIV) co-infection relative to non-indigenous patients. Historical and personal trauma has a major role in the participation of high risk behaviors and associated diseases. Although emerging treatments provide hope, combating HCV-related morbidity and mortality will require interventions that address the etiology of broken spirit diseases.

  4. Temperature and plant species control over litter decomposition in Alaskan tundra

    SciTech Connect

    Hobbie, S.E.

    1996-11-01

    This study compared effects of increased temperature and litter from different Alaskan tundra plant species on cycling of carbon and nitrogen through litter and soil in microcosms. Warming between 4{degrees} and 10{degrees}C significantly increased rates of soil and litter respiration, litter decomposition, litter nitrogen release, and soil net nitrogen mineralization. Thus, future warming will directly increase rates of carbon and nitrogen cycling through litter and soil in tundra. In addition, differences among species` litter in rates of decomposition, N release, and effects on soil net nitrogen mineralization were sometimes larger than differences between the two temperature treatments within a species. Thus, changes in plant community structure and composition associated with future warming will have important consequences for how elements cycle through litter and soil in tundra. In general, species within a growth form (graminoids, evergreen shrubs, deciduous shrubs, and mosses) were more similar in their effects on decomposition than were species belonging to different growth forms, with gramminoid litter having the fastest rate and litter of deciduous shrubs and mosses having the slowest rates. Differences in rates of litter decomposition were more related to carbon quality than to nitrogen concentration. Increased abundance of deciduous shrubs with future climate warming will promote carbon storage, because of their relatively large allocation to woody stems that decompose slowly. Changes in moss abundance will also have important consequences for future carbon and nitrogen cycling, since moss litter is extremely recalcitrant and has a low potential to immobilize nitrogen. 82 refs., 8 figs., 7 tabs.

  5. No evidence of metabolic depression in Western Alaskan juvenile Steller sea lions (Eumetopias jubatus).

    PubMed

    Hoopes, Lisa A; Rea, Lorrie D; Christ, Aaron; Worthy, Graham A J

    2014-01-01

    Steller sea lion (Eumetopias jubatus) populations have undergone precipitous declines through their western Alaskan range over the last four decades with the leading hypothesis to explain this decline centering around changing prey quality, quantity, or availability for this species (i.e., nutritional stress hypothesis). Under chronic conditions of reduced food intake sea lions would conserve energy by limiting energy expenditures through lowering of metabolic rate known as metabolic depression. To examine the potential for nutritional stress, resting metabolic rate (RMR) and body composition were measured in free-ranging juvenile Steller sea lions (N = 91) at three distinct geographical locations (Southeast Alaska, Prince William Sound, Central Aleutian Islands) using open-flow respirometry and deuterium isotope dilution, respectively. Average sea lion RMR ranged from 6.7 to 36.2 MJ d(-1) and was influenced by body mass, total body lipid, and to a lesser extent, ambient air temperature and age. Sea lion pups captured in the Aleutian Islands (region of decline) had significantly greater body mass and total body lipid stores when compared to pups from Prince William Sound (region of decline) and Southeast Alaska (stable region). Along with evidence of robust body condition in Aleutian Island pups, no definitive differences were detected in RMR between sea lions sampled between eastern and western populations that could not be accounted for by higher percent total body lipid content, suggesting that that at the time of this study, Steller sea lions were not experiencing metabolic depression in the locations studied.

  6. Geographic and seasonal variation of dissolved methane and aerobic methane oxidation in Alaskan lakes

    NASA Astrophysics Data System (ADS)

    Martinez-Cruz, K.; Sepulveda-Jauregui, A.; Anthony, K. Walter; Thalasso, F.

    2015-03-01

    Methanotrophic bacteria play an important role oxidizing a significant fraction of methane (CH4) produced in lakes. Aerobic CH4 oxidation depends on lake CH4 and oxygen (O2) concentrations, temperature, and organic carbon input to lakes, including from thawing permafrost in thermokarst (thaw)-affected lakes. Given the large variability in these environmental factors, CH4 oxidation is expected to be subject to large seasonal and geographic variations, which have been scarcely reported in the literature. In the present study, we measured CH4 oxidation rates in 30 Alaskan lakes along a north-south latitudinal transect during winter and summer with a new field laser spectroscopy method. Additionally, we measured dissolved CH4 and O2 concentrations. We found that in the winter, aerobic CH4 oxidation was mainly controlled by the dissolved O2 concentration, while in the summer it was controlled primarily by the CH4 concentration, which was in deficit compared to dissolved O2. The permafrost environment of the lakes was identified as another key factor. Thermokarst (thaw) lakes formed in yedoma-type permafrost had significantly higher CH4 oxidation rates compared to other thermokarst and non-thermokarst lakes formed in non-yedoma permafrost environments. These results confirm that landscape processes play an important role in lake CH4 cycling.

  7. Chemical and biological assessment of two offshore drilling sites in the Alaskan Arctic.

    PubMed

    Trefry, John H; Dunton, Kenneth H; Trocine, Robert P; Schonberg, Susan V; McTigue, Nathan D; Hersh, Eric S; McDonald, Thomas J

    2013-05-01

    A retrospective chemical and biological study was carried out in Camden Bay, Alaskan Beaufort Sea, where single exploratory oil wells were drilled at two sites more than two decades ago. Barium from discharged drilling mud was present in sediments at concentrations as high as 14%, ~200 times above background, with significantly higher concentrations of Ba, but not other metals, within 250 m of the drilling site versus reference stations. Elevated concentrations of Cr, Cu, Hg and Pb were found only at two stations within 25 m of one drilling site. Concentrations of total polycyclic aromatic hydrocarbons (TPAH) were not significantly different at reference versus drilling-site stations; however, TPAH were elevated in Ba-rich layers from naturally occurring perylene in ancient formation cuttings. Infaunal biomass and species abundance were not significantly different at reference versus drilling-site stations; infauna were less diverse at drilling-site stations. Our assessment showed that discharges from single wells within large areas caused minimal long-term, adverse impacts to the benthic ecosystem. PMID:23535013

  8. No Evidence of Metabolic Depression in Western Alaskan Juvenile Steller Sea Lions (Eumetopias jubatus)

    PubMed Central

    Hoopes, Lisa A.; Rea, Lorrie D.; Christ, Aaron; Worthy, Graham A. J.

    2014-01-01

    Steller sea lion (Eumetopias jubatus) populations have undergone precipitous declines through their western Alaskan range over the last four decades with the leading hypothesis to explain this decline centering around changing prey quality, quantity, or availability for this species (i.e., nutritional stress hypothesis). Under chronic conditions of reduced food intake sea lions would conserve energy by limiting energy expenditures through lowering of metabolic rate known as metabolic depression. To examine the potential for nutritional stress, resting metabolic rate (RMR) and body composition were measured in free-ranging juvenile Steller sea lions (N = 91) at three distinct geographical locations (Southeast Alaska, Prince William Sound, Central Aleutian Islands) using open-flow respirometry and deuterium isotope dilution, respectively. Average sea lion RMR ranged from 6.7 to 36.2 MJ d−1 and was influenced by body mass, total body lipid, and to a lesser extent, ambient air temperature and age. Sea lion pups captured in the Aleutian Islands (region of decline) had significantly greater body mass and total body lipid stores when compared to pups from Prince William Sound (region of decline) and Southeast Alaska (stable region). Along with evidence of robust body condition in Aleutian Island pups, no definitive differences were detected in RMR between sea lions sampled between eastern and western populations that could not be accounted for by higher percent total body lipid content, suggesting that that at the time of this study, Steller sea lions were not experiencing metabolic depression in the locations studied. PMID:24416394

  9. Cost-Optimal Pathways to 75% Fuel Reduction in Remote Alaskan Villages

    SciTech Connect

    Simpkins, Travis; Cutler, Dylan; Hirsch, Brian; Olis, Dan; Anderson, Kate

    2015-08-01

    There are thousands of isolated, diesel-powered microgrids that deliver energy to remote communities around the world at very high energy costs. The Remote Communities Renewable Energy program aims to help these communities reduce their fuel consumption and lower their energy costs through the use of high penetration renewable energy. As part of this program, the REopt modeling platform for energy system integration and optimization was used to analyze cost-optimal pathways toward achieving a combined 75% reduction in diesel fuel and fuel oil consumption in a select Alaskan village. In addition to the existing diesel generator and fuel oil heating technologies, the model was able to select from among wind, battery storage, and dispatchable electric heaters to meet the electrical and thermal loads. The model results indicate that while 75% fuel reduction appears to be technically feasible it may not be economically viable at this time. When the fuel reduction target was relaxed, the results indicate that by installing high-penetration renewable energy, the community could lower their energy costs by 21% while still reducing their fuel consumption by 54%.

  10. Psychrotrophic strain of Janthinobacterium lividum from a cold Alaskan soil produces prodigiosin.

    PubMed

    Schloss, Patrick D; Allen, Heather K; Klimowicz, Amy K; Mlot, Christine; Gross, Jessica A; Savengsuksa, Sarah; McEllin, Jennifer; Clardy, Jon; Ruess, Roger W; Handelsman, Jo

    2010-09-01

    We have explored the microbial community in a nonpermafrost, cold Alaskan soil using both culture-based and culture-independent approaches. In the present study, we cultured >1000 bacterial isolates from this soil and characterized the collection of isolates phylogenetically and functionally. A screen for antibiosis identified an atypical, red-pigmented strain of Janthinobacterium lividum (strain BR01) that produced prodigiosin when grown at cool temperatures as well as strains (e.g., strain BP01) that are more typical of J. lividium, which produce a purple pigment, violacein. Both purple- and red-pigmented strains exhibited high levels of resistance to beta-lactam antibiotics. The prodigiosin pathway cloned from J. lividium BR01 was expressed in the heterologous host, Escherichia coli, and the responsible gene cluster differs from that of a well-studied prodigiosin producer, Serratia sp. J. lividum BR01 is the first example of a prodigiosin-producer among the beta-Proteobacteria. The results show that characterization of cultured organisms from previously unexplored environments can expand the current portrait of the microbial world.

  11. 7 CFR 29.2316 - Wet (W).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.2316 Section 29.2316 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2316 Wet...

  12. 7 CFR 29.3567 - Wet (W).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.3567 Section 29.3567 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3567 Wet (W). Any sound tobacco containing excessive moisture to the extent that it is...

  13. 7 CFR 29.3077 - Wet (W).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.3077 Section 29.3077 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Wet (W). Any sound tobacco containing excessive moisture to the extent that it is in an unsafe...

  14. 7 CFR 29.1083 - Wet (W).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.1083 Section 29.1083 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1083 Wet (W). Any sound tobacco containing excessive moisture to the extent that it is...

  15. 7 CFR 29.2570 - Wet (W).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.2570 Section 29.2570 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2570 Wet (W). Any sound tobacco...

  16. Wet runways. [aircraft landing and directional control

    NASA Technical Reports Server (NTRS)

    Horne, W. B.

    1975-01-01

    Aircraft stopping and directional control performance on wet runways is discussed. The major elements affecting tire/ground traction developed by jet transport aircraft are identified and described in terms of atmospheric, pavement, tire, aircraft system and pilot performance factors or parameters. Research results are summarized, and means for improving or restoring tire traction/aircraft performance on wet runways are discussed.

  17. A reconnaissance survey of southern Alaskan lakes by high-resolution reflection seismics and short sediment coring - a first step towards a calibrated lacustrine paleoseismometer at the Alaskan-Aleutian subduction zone

    NASA Astrophysics Data System (ADS)

    Strupler, M.; Moernaut, J.; Haeussler, P. J.; De Batist, M. A.; Bender, A. M.

    2012-12-01

    The Good Friday earthquake of 27 March 1964 (Mw 9.2) ruptured an 800 km-length of the Alaskan-Aleutian megathrust, producing significant changes in the landscape morphology, both in subaerial and in subaquatic environments. Lake sediments can represent excellent archives for paleoseismic studies, as traces of seismically-induced subaquatic landslides and related turbidites are protected from erosion by later sedimentation and are often embedded in background sediments that are easy to date. In order to test the archive quality of the Alaskan lakes, we conducted a reconnaissance survey on three lakes on the Kenai Peninsula (Kenai, Skilak and Tustumena lakes) and on Eklutna lake (near Anchorage). We collected seismic data with a 3.5 kHz pinger system. Dense seismic grids reveal a glacially inherited basin morphology, which is infilled by lacustrine sediments that show numerous earthquake-related features. Multiple landslide deposits and associated turbidites at several stratigraphic levels indicate they were triggered by strong earthquake shaking. The relatively large volumes of the landslide deposits might be a result of the high sedimentation rates in these periglacial lakes. Short gravity cores reveal a detailed sedimentary imprint of the 1964 earthquake in different sub-basins of the investigated lakes. The irregular lamination pattern of the cores reflects altering conditions of the climatic, biological, hydrological and seismological factors in the investigation area. In a further phase of our project, long sediment cores will be taken in these lakes. The analysis and dating of these long sedimentary records is expected to yield information on the periodicity of megathrust earthquakes in the Prince William Sound Segment of the Alaskan-Aleutian subduction zone for the last few thousand years. The results of this study will contribute to an improved earthquake-hazard assessment for the Kenai Peninsula and the more densely-populated Anchorage area.

  18. Thin wetting film lensless imaging

    NASA Astrophysics Data System (ADS)

    Allier, C. P.; Poher, V.; Coutard, J. G.; Hiernard, G.; Dinten, J. M.

    2011-03-01

    Lensless imaging has recently attracted a lot of attention as a compact, easy-to-use method to image or detect biological objects like cells, but failed at detecting micron size objects like bacteria that often do not scatter enough light. In order to detect single bacterium, we have developed a method based on a thin wetting film that produces a micro-lens effect. Compared with previously reported results, a large improvement in signal to noise ratio is obtained due to the presence of a micro-lens on top of each bacterium. In these conditions, standard CMOS sensors are able to detect single bacterium, e.g. E.coli, Bacillus subtilis and Bacillus thuringiensis, with a large signal to noise ratio. This paper presents our sensor optimization to enhance the SNR; improve the detection of sub-micron objects; and increase the imaging FOV, from 4.3 mm2 to 12 mm2 to 24 mm2, which allows the detection of bacteria contained in 0.5μl to 4μl to 10μl, respectively.

  19. Dynamic wetting at the nanoscale

    NASA Astrophysics Data System (ADS)

    Amberg, Gustav; Nakamura, Yoshinori; Carlson, Andreas; Shiomi, Junichiro

    2013-11-01

    Although the capillary spreading of a drop on a dry substrate is well studied, the physical mechanisms that govern the dynamics remain challenging. Here we study the dynamics of spreading of partially wetting nano-droplets, by combining molecular dynamics and continuum simulations. The latter accounts for all the relevant hydrodynamics, i.e. capillarity, inertia and viscous stresses. By coordinated continuum and molecular dynamics simulations, the macroscopic model parameters are extracted. For a Lennard-Jones fluid spreading on a planar surface, the liquid slip on the substrate is found to be crucial for the motion of the contact line. Evaluation of the different contributions to the energy transfer shows that the liquid slip generates dissipation of the same order as the bulk viscous dissipation or the energy transfer to kinetic energy. We also study the dynamics of spreading on a substrate with a periodic nanostructure. Here it is found that a nanostructure with a length scale commensurate with molecular size completely inhibits the liquid slip. This reduces the spreading speed by about 30%. This work is partially supported by the Japan Science and Technology Agency, CREST, the Swedish Research Council, the Japan Society for the Promotion of Science, and the Sasakawa foundation.

  20. The Responses of the Quantitative Characteristics of a Ramet Population of the Ephemeroid Rhizomatous Sedge Carex physodes to the Moisture Content of the Soil in Various Locations on Sand Dunes

    PubMed Central

    Abudureheman, Buhailiqiemu; Liu, Huiliang; Zhang, Daoyuan; Guan, Kaiyun; Zhang, Yongkuan

    2014-01-01

    In this study, the soil moisture content was measured, and the quantitative characteristics of this sedge species were compared. The phenotypic plasticity of each parameter and the linear regression relationships were analyzed. The results showed that the soil moisture content was significantly affected by location, soil depth, and sampling date. The aboveground biomass, underground biomass, biomass density, and population density at the peak were significantly higher than elsewhere on the dune. However, the morphological plasticity index of the quantitative characteristics was higher at the base and middle of the dune. When the soil moisture content decreased, the underground biomass and ramet biomass density increased. The aboveground and underground biomasses were strongly negatively correlated, but the ramet height and aboveground biomass were strongly positively correlated. These results indicated that the soil water content significantly affected the clonal growth of C. physodes. The responsiveness of C. physodes may be adaptive when the soil resource supply is low. The strong morphological plasticity of the species appears to be ecologically important for the maintenance and dominance of this species in the dune habitat. PMID:25045722

  1. The responses of the quantitative characteristics of a ramet population of the ephemeroid rhizomatous sedge Carex physodes to the moisture content of the soil in various locations on sand dunes.

    PubMed

    Abudureheman, Buhailiqiemu; Liu, Huiliang; Zhang, Daoyuan; Guan, Kaiyun; Zhang, Yongkuan

    2014-01-01

    In this study, the soil moisture content was measured, and the quantitative characteristics of this sedge species were compared. The phenotypic plasticity of each parameter and the linear regression relationships were analyzed. The results showed that the soil moisture content was significantly affected by location, soil depth, and sampling date. The aboveground biomass, underground biomass, biomass density, and population density at the peak were significantly higher than elsewhere on the dune. However, the morphological plasticity index of the quantitative characteristics was higher at the base and middle of the dune. When the soil moisture content decreased, the underground biomass and ramet biomass density increased. The aboveground and underground biomasses were strongly negatively correlated, but the ramet height and aboveground biomass were strongly positively correlated. These results indicated that the soil water content significantly affected the clonal growth of C. physodes. The responsiveness of C. physodes may be adaptive when the soil resource supply is low. The strong morphological plasticity of the species appears to be ecologically important for the maintenance and dominance of this species in the dune habitat.

  2. Repeat Photography of Alaskan Glaciers and Landscapes as Both Art and as a Means of Communicating Climat Change

    NASA Astrophysics Data System (ADS)

    Molnia, B. F.

    2013-12-01

    For nearly 15 years, I have used repeat photography of Alaskan glaciers and landscapes to communicate to fellow scientists, policymakers, the media, and society that Alaskan glaciers and landscapes have been experiencing significant change in response to post-Little Ice Age climate change. I began this pursuit after being contacted by a U.S. Department of the Interior senior official who requested unequivocal and unambiguous documentation that climate change was real and underway. After considering several options as to how best respond to this challenge, I decided that if a picture is worth a thousand words, then a pair of photographs, both with the same field of view, spanning a century or more, and showing dramatic differences, would speak volumes to documenting that dynamic climate change is occurring over a very broad region of Alaska. To me, understating the obvious with photographic pairs was the best mechanism to present irrefutable, unambiguous, nonjudgmental, as well as unequivocal visual documentation that climate change was both underway and real. To date, more than 150 pairs that meet these criteria have been produced. What has surprised me most is that the many of the photographs contained in the pairs present beautiful images of stark, remote landscapes that convey the majestic nature of this dynamic region with its unique topography and landscapes. Typically, over periods of just several decades, the photographed landscapes change from black and white to blue and green. White ice becomes blue water and dark rock becomes lush vegetation. Repeat photography is a technique in which a historical photograph and a modern photograph, both having the same field of view, are compared and contrasted to quantitatively and qualitatively determine their similarities and differences. I have used this technique from both ground-based photo stations and airborne platforms at Alaskan locations in Kenai Fjords National Park, Glacier Bay National Park and Preserve

  3. Critical point wetting drop tower experiment

    NASA Technical Reports Server (NTRS)

    Kaukler, William F.

    1990-01-01

    The 100 m Drop Tower at NASA-Marshall was used to provide the step change in acceleration from 1.0 to 0.0005 g. An inter-fluid meniscus oscillates vertically within a cylindrical container when suddenly released from earth's gravity and taken into a microgravity environment. Oscillations damp out from energy dissipative mechanisms such as viscosity and interfacial friction. Damping of the oscillations by the later mechanism is affected by the nature of the interfacial junction between the fluid-fluid interface and the container wall. In earlier stages of the project, the meniscus shape which developed during microgravity conditions was applied to evaluations of wetting phenomena near the critical temperature. Variations in equilibrium contact angle against the container wall were expected to occur under critical wetting conditions. However, it became apparent that the meaningful phenomenon was the damping of interfacial oscillations. This latter concept makes up the bulk of this report. Perfluoromethyl cyclohexane and isopropanol in glass were the materials used for the experiment. The wetting condition of the fluids against the wall changes at the critical wetting transition temperature. This change in wetting causes a change in the damping characteristics of the interfacial excursions during oscillation and no measurable change in contact angle. The effect of contact line friction measured above and below the wetting transition temperature was to increase the period of vertical oscillation for the vapor-liquid interface when below the wetting transition temperature.

  4. Alcohol Screening and Brief Intervention as Standard Practice: Working with the American Indian/Native Alaskan Populations

    PubMed Central

    Patterson Silver Wolf (Adelv unegv Waya), David A.; Duran, Bonnie; Dulmus, Catherine N.; Manning, Amy R.

    2014-01-01

    Alcohol use and the resulting problems associated with high-risk drinking in the American Indian/Native Alaskan (AI/NA) population are well-documented, as alcohol misuse has taken an incredible toll on many AI/NA communities. Presently, both overall health issues and alcohol use occur disproportionately within this population. This article provides an updated overview of the impact of alcohol use in the United States and within AI/NA communities specifically. It also provides recommendations for an alcohol-related screening and brief intervention instrument that social workers can begin using in their practice and can be utilized within the AI/NA community. PMID:25580074

  5. Importance of the eastern Alaskan Beaufort Sea to feeding bowhead whales, 1985. Final report, June 1985-May 1986

    SciTech Connect

    Richardson, W.J.

    1986-05-01

    The two-year project is designed to quantify what proportion of the energy requirements of Western Arctic bowheads is provided by food acquired in the Eastern part of the Alaskan Beaufort Sea. The report describes results from Year 1 fieldwork in September and early October 1985. Water masses were studied by boat-based sampling and by airborne and satellite remote sensing. Zooplankton composition, biomass, distribution, patchiness, and energy content were documented by boat-based sampling. The distribution, numbers and activities of bowheads were determined by aerial surveys and behavioral observations. Bowheads probably consume several times more food there in some other years.

  6. Sulfur dioxide emissions from Alaskan volcanoes quantified using an ultraviolet SO_{2} camera

    NASA Astrophysics Data System (ADS)

    Kern, Christoph; Werner, Cynthia; Kelly, Peter; Brewer, Ian; Ketner, Dane; Paskievitch, John; Power, John

    2016-04-01

    Alaskan volcanoes are difficult targets for direct gas measurements as they are extremely remote and their peaks are mostly covered in ice and snow throughout the year. This makes access extremely difficult. In 2015, we were able to make use of an ultraviolet SO2 camera to quantify the SO2 emissions from Augustine Volcano, Redoubt Volcano, Mount Cleveland and Shishaldin Volcano in the Aleutian Arc. An airborne gas survey performed at Augustine Volcano in April 2015 found that the SO2 emission rate from the summit area was below 10 tonnes per day (t/d). SO2 camera measurements were performed two months later (June 2015) from a snow-free area just 100 meters from the fumarole on the south side of Augustine's summit dome to maximize camera sensitivity. Though the visible appearance of the plume emanating from the fumarole was opaque, the SO2 emissions were only slightly above the 40 ppmṡm detection limit of the SO2 camera. Still, SO2 could be detected and compared to coincident MultiGAS measurements of SO2, CO2 and H2S. At Redoubt Volcano, SO2 camera measurements were conducted on 13 June 2015 from a location 2 km to the north of the final 72x106 m3 dome extruded during the 2009 eruption. Imagery was collected of the plume visibly emanating from the top of the dome. Preliminary evaluation of the imagery and comparison with a coincident, helicopter-based DOAS survey showed that SO2 emission rates had dropped below 100 t/d (down from 180 t/d measured in April 2014). Mount Cleveland and Shishaldin Volcano were visited in August 2015 as part of an NSF-funded ship-based research expedition in the Central Aleutian Arc. At Mount Cleveland, inclement weather prohibited the collection of a lengthy time-series of SO2 camera imagery, but the limited data that was collected shows an emission rate of several hundred t/d. At Shishaldin, several hours of continuous imagery was acquired from a location 5 km east of the summit vent. The time series shows an SO2 emission rate of

  7. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2002

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sánchez, John; Estes, Steve; McNutt, Stephen R.; Paskievitch, John

    2003-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Power and others, 1993; Jolly and others, 1996; Jolly and others, 2001; Dixon and others, 2002). The primary objectives of this program are the seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the basic seismic data and changes in the seismic monitoring program for the period January 1, 2002 through December 31, 2002. Appendix G contains a list of publications pertaining to seismicity of Alaskan volcanoes based on these and previously recorded data. The AVO seismic network was used to monitor twenty-four volcanoes in real time in 2002. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai Volcanic Group (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Great Sitkin Volcano, and Kanaga Volcano (Figure 1). Monitoring highlights in 2002 include an earthquake swarm at Great Sitkin Volcano in May-June; an earthquake swarm near Snowy Mountain in July-September; low frequency (1-3 Hz) tremor and long-period events at Mount Veniaminof in September-October and in December; and continuing volcanogenic seismic swarms at Shishaldin Volcano throughout the year. Instrumentation and data acquisition highlights in 2002 were the installation of a subnetwork on Okmok Volcano, the establishment of telemetry for the Mount Veniaminof subnetwork, and the change in the data acquisition system to

  8. Martian and Ionian Analogs of Permafrost-Volcano Interactions in Alaskan Permafrost

    NASA Astrophysics Data System (ADS)

    Kargel, J. S.; Beget, J. E.; Skinner, J. A.; Wessels, R.

    2005-12-01

    Volcanic landforms in Alaskan lowland permafrost exhibit several unique morphological attributes, as described in a companion AGU abstract (Beget et al.). These features include (1) giant maar sizes (in Bering Land Bridge National Preserve) an order of magnitude larger than common in non-permafrost terrains, (2) composite volcanic forms produced by repeated maar-forming explosions (the novel Ingakslugwat-type volcano in Yukon Delta), and (3) super-inflated lava flows with marginal thermokarst pits (Lost Jim flow, Imuruk Lake Volcanic Field, Bering Land Bridge area). We have identified on Mars, in areas not indicating glaciation, several landforms and on Io an active volcanic process that might be analogs of these in Alaska. On Mars, within and near Elysium (Galaxias Fossae and Hrad Vallis region) multiple crater-like depressions occur with other volcanic features. Their characteristics suggest that the depressions are maars. The composite structures suggest similarities to Ingakslugwat volcanoes. Possible analogs of giant oversize maars also have been identified on Mars. In addition to surface gravitational differences between Earth and Mars, it seems likely that volatile composition is a key aspect controlling the explosivity and sizes of maars on both planets. In Alaska, we suspect that volcanic interactions with methane clathrate hydrate-rich permafrost tends to yield larger maar sizes than with ice-rich permafrost or ground water. This working hypothesis fits well with observations that the giant maars formed during the climatically coldest periods (Beget et al., 2005, this conference). During those periods, permafrost was thick, strong, and unpunctured by lakes and rivers, and so it could have trapped clathrate-forming gases. During interglacials, thinner permafrost and the widespread occurrence of thaw lakes and surface streams may cause the permafrost to be ineffective in confining ascending gases, and so clathrates were absent or not abundant, and volcanic

  9. Wetting transitions at soft, sliding interfaces

    NASA Astrophysics Data System (ADS)

    Martin, A.; Clain, J.; Buguin, A.; Brochard-Wyart, F.

    2002-03-01

    We observe (by optical interferometry) the contact of a rubber cap squeezing a nonwetting liquid against a plate moving at velocity U. At low velocities, the contact is dry. It becomes partially wet above a threshold velocity Vc1, with two symmetrical dry patches on the rear part. Above a second velocity Vc2, the contact is totally wet. This regime U>Vc2 corresponds to the hydroplaning of a car (decelerating on a wet road). We interpret the transitions at Vc1, Vc2 in terms of a competition between (a) liquid invasion induced by shear (b) spontaneous dewetting of the liquid (between nonwettable surfaces).

  10. Asbestos/NESHAP adequately wet guidance

    SciTech Connect

    Shafer, R.; Throwe, S.; Salgado, O.; Garlow, C.; Hoerath, E.

    1990-12-01

    The Asbestos NESHAP requires facility owners and/or operators involved in demolition and renovation activities to control emissions of particulate asbestos to the outside air because no safe concentration of airborne asbestos has ever been established. The primary method used to control asbestos emissions is to adequately wet the Asbestos Containing Material (ACM) with a wetting agent prior to, during and after demolition/renovation activities. The purpose of the document is to provide guidance to asbestos inspectors and the regulated community on how to determine if friable ACM is adequately wet as required by the Asbestos NESHAP.

  11. Biomarkers as Indicators of Respiration During Laboratory Incubations of Alaskan Arctic Tundra Permafrost Soils

    NASA Astrophysics Data System (ADS)

    Hutchings, J.; Schuur, E.; Bianchi, T. S.; Bracho, R. G.

    2015-12-01

    High latitude permafrost soils are estimated to store 1,330 - 1,580 Pg C, which account for ca. 40% of global soil C and nearly twice that of atmospheric C. Disproportionate heating of high latitude regions during climate warming potentially results in permafrost thaw and degradation of surficial and previously-frozen soil C. Understanding how newly-thawed soils respond to microbial degradation is essential to predicting C emissions from this region. Laboratory incubations have been a key tool in understanding potential respiration rates from high latitude soils. A recent study found that among the common soil measurements, C:N was the best predictor of C losses. Here, we analyzed Alaskan Arctic tundra soils from before and after a nearly 3-year laboratory incubation. Bulk geochemical values as well as the following biomarkers were measured: lignin, amino acids, n-alkanes, and glycerol dialkyl glycerol tetraethers (GDGT). We found that initial C:N did not predict C losses and no significant change in C:N between initial and final samples. The lignin acid to aldehyde (Ad:Al) degradation index showed the same results with a lack of C loss prediction and no significant change during the experiment. However, we did find that C:N and Ad:Al had a significant negative correlation suggesting behavior consistent with expectations. The failure to predict C losses was likely influenced by a number of factors, including the possibility that biomarkers were tracking a smaller fraction of slower cycling components of soil C. To better interpret these results, we also used a hydroxyproline-based amino acid degradation index and n-alkanes to estimate the contribution Sphagnum mosses to soil samples - known to have slower turnover times than vascular plants. Finally, we applied a GDGT soil temperature proxy to estimate the growing season soil temperatures before each incubation, as well as investigating the effects of incubation temperature on the index's temperature estimate.

  12. An estimate of carbon emissions from 2004 wildfires across Alaskan Yukon River Basin

    PubMed Central

    Tan, Zhengxi; Tieszen, Larry L; Zhu, Zhiliang; Liu, Shuguang; Howard, Stephen M

    2007-01-01

    Background Wildfires are an increasingly important component of the forces that drive the global carbon (C) cycle and climate change as progressive warming is expected in boreal areas. This study estimated C emissions from the wildfires across the Alaskan Yukon River Basin in 2004. We spatially related the firescars to land cover types and defined the C fractions of aboveground biomass and the ground layer (referring to the top 15 cm organic soil layer only in this paper) consumed in association with land cover types, soil drainage classes, and the C stocks in the ground layer. Results The fires led to a burned area of 26,500 km2 and resulted in the total C emission of 81.1 ± 13.6 Tg (Tg, Teragram; 1 Tg = 1012 g) or 3.1 ± 0.7 kg C m-2 burned. Of the total C emission, about 73% and 27% could be attributed to the consumption of the ground layer and aboveground biomass, respectively. Conclusion The predominant contribution of the ground layer to the total C emission implies the importance of ground fuel management to the control of wildfires and mitigation of C emissions. The magnitude of the total C emission depends on fire extent, while the C loss in kg C m-2 burned is affected strongly by the ground layer and soil drainage condition. The significant reduction in the ground layer by large fires may result in profound impacts on boreal ecosystem services with an increase in feedbacks between wildfires and climate change. PMID:18093322

  13. Widespread Burning of Alaskan Boreal Forests Overcomes Fuel Limitation in the 21st Century

    NASA Astrophysics Data System (ADS)

    Kelly, R.; Hu, F.

    2015-12-01

    Fire is a key determinant of the structure and function of boreal forest ecosystems. Boreal fire regimes have been climate-limited in recent decades, and future climate warming is predicted to drive a pronounced increase in fire activity, likely resulting in carbon release from the boreal biome and positive feedback to climate change. Fuel limitation could slow fire regime change by reducing the abundance of mature vegetation on the landscape, but this mechanism remains poorly quantified and is thus excluded from forecasts of future boreal burning. We developed a novel statistical model that links regional area burned to mean landscape age, a proxy for fuel limitation due to cumulative past burning. Fit to historical fire observations from interior Alaska, the model detects significant evidence of fire-vegetation feedback and provides the first quantitative estimate of its effects on regional fire regimes. These effects were subtle during the past 60 yr, but they will become increasingly influential as climate warming promotes higher fire activity. By the end of the 21st century, fuel limitation reduces predicted area burned by 40-50% relative to predictions based on climate alone, and diminishes the difference between fire regimes expected under alternate future climate scenarios. Nevertheless, annual area burned will approximately double during the coming century as fire becomes more widespread in spite of regional fuel limitation. Furthermore, changes to the fire regime and mean landscape age by the end of the century could represent a fundamental shift in the Alaskan boreal ecosystem. Our model structure facilitates linking fire regime predictions to ecosystem and Earth system models and could help reduce uncertainty in these models due to poorly constrained initial conditions. We demonstrate this approach using the Terrestrial Ecosystem Model, which has been calibrated extensively for applications in simulating boreal carbon dynamics. Results suggest that

  14. Mercury Methylation in Alaskan Peatlands Spanning a Large Range of Trophic Structure

    NASA Astrophysics Data System (ADS)

    Krabbenhoft, D. P.; Zhang, L.; Hines, M. E.; Barkay, T.; Schaefer, J.; Aiken, G.

    2015-12-01

    The process of mercury (Hg) methylation has long been recognized as a key area of research in order to understand spatial and temporal variability of toxic methylmercury (MeHg) on the landscape. Numerous factors affect MeHg production, the most important generally falling into those that affect inorganic Hg(II) bioavailability (e.g., Hg(II) concentration and ligand composition), and those that affect microbial community composition and activity. The principal goal of this project is to decipher the details of MeHg production in Alaskan peatlands exhibiting a range of trophic status, including those lacking in electron acceptors that support the traditional respiratory pathway of MeHg production (e.g., sulfate reduction). MeHg production is carried out by a diverse group of microorganisms that possess the gene cluster (hgcAB), including the well-studied sulfate and iron- reducing bacteria (SRB and FeRB). However, less well known bacteria also possess the hgcAB genes, including: syntrophs, methanogens, acetogens, and fermenters. Methylation and demethylation activities were determined by injecting trace levels of the stable isotope (198Hg and Me204Hg) into intact peat cores. In addition, the short-lived radioisotope 197Hg was used in laboratory incubations. Laboratory studies also included assays for changes in diagnostic gas concentrations (CH4, CO2, H2) and LMW organic acids (formate, acetate, propionate, butyrate) to infer specific microbial processes, and the use of genomics to confirm microbial assemblages and the presence/absence of hgcAB genes. Overall, we observed Hg methylation rates were greatest at minerotrophic sites with active syntrophy and methanogenesis. Methylation and demethylation rates corresponded significantly across sites. There was no evidence of SO4- reduction in these samples, and addition of SO4- did not stimulate methylation suggesting that methylation was conducted by SRB that were metabolizing syntrophically and/or by fermentation.

  15. Sublacustrine Landslides in Several Alaskan Lakes Reveal a Long History of Strong Earthquake Shaking

    NASA Astrophysics Data System (ADS)

    Praet, N.; Moernaut, J.; Van Daele, M. E.; Vandekerkhove, E.; Boes, E.; Strupler, M. M.; Haeussler, P. J.; De Batist, M. A. O.

    2015-12-01

    In 1964, the "Good Friday Earthquake" ruptured a 800 km-long segment of the Alaskan-Aleutian Subduction Zone (AASZ), representing the largest measured earthquake in North America (Mw 9.2). Lake sediments potentially record such large earthquakes, since seismic shaking can generate subaquatic mass-wasting deposits. Several short cores, high-resolution seismic (3.5 kHz) and multibeam (50khz) data were collected in Eklutna, Skilak and Kenai Lakes in southern Alaska. The data reveal the presence of sublacustrine landslides related to the 1964 earthquake. The seismic profiles also show a succession of older landslide deposits in the subsurface. It has been shown that earthquake shaking with intensities of > VII can trigger such landslides and as such they are useful for paleoseismology research, especially in low-seismicity regions. In high-seismicity regions (e.g. southcentral Chile), however, the turbidite record has shown to be a much more sensitive seismometer, because frequent and strong seismic shaking is under-represented in landslide deposits in the lake records. Eklutna, Skilak and Kenai lakes are also located in a high-seismicity setting (the Prince William Sound segment of the AASZ), but they exhibit significantly larger sedimentation rates (4 mm/yr), potentially reducing the effect of under-representation. Our multilake approach allows us to compare landslide records between lakes with different characteristics: low slope gradients and sedimentation rates cause under-representation of the landslides in Skilak Lake with respect to other independent paleoseismic records, while steeper slopes and higher sedimentation rates in Eklutna Lake produce more frequent event deposits, potentially thus resulting in a more precise sedimentary archive of past earthquake events. Multiple lake records will also help us understand segment boundaries of megathrust earthquakes. This is crucial for inferring information on variability between ruptures and interplate coupling.

  16. Influence of fire frequency on carbon consumption in Alaskan blackspruce forests

    NASA Astrophysics Data System (ADS)

    Hoy, E.; Kasischke, E. S.

    2014-12-01

    Increasing temperatures and drier conditions within the boreal forests of Alaska have resulted in increases in burned area and fire frequency, which alter carbon storage and emissions. In particular, analyses of satellite remote sensing data showed that >20% of the area impacted by fires in interior Alaska occurred in areas that had previously burned since 1950 (e.g., short to intermediate interval fires). Field studies showed that in immature black spruce forests ~ 35 to 55 years old organic layers experienced deep burning regardless of topographic position or seasonality of burning, factors that control depth of burning in mature black spruce forests. Here, refinements were made to a carbon consumption model to account for variations in fuel loads and fraction of carbon consumed associated with fire frequency based on quantifying burned area in recently burned sites using satellite imagery. An immature black spruce (Picea mariana) fuel type (including stands of ~0-50 years) was developed which contains new ground-layer carbon consumption values in order to more accurately account for differences between various age classes of black spruce forest. Both versions of the model were used to assess carbon consumption during 100 fire events (over 4.4 x 10^6 ha of burned area) from two recent ultra-large fire years (2004 and 2005). Using the improved model to better attribute fuel type and consumption resulted in higher ground-layer carbon consumption (4.9% in 2004 and 6.8% in 2005) than previously estimated. These adjustments in ground-layer burning resulted in total carbon consumption within 2004 and 2005 of 63.5 and 42.0 Tg of carbon, respectively. Results from this research could be incorporated into larger scale modeling efforts to better assess changes in the climate-fire-vegetation dynamics in interior Alaskan boreal forests, and to understand the impacts of these changes on carbon consumption and emissions.

  17. Microbial Communities in Methane Hydrate-Bearing Sediments from the Alaskan North Slope

    NASA Astrophysics Data System (ADS)

    Schwartz, A.; Briggs, B.; Colwell, F.

    2008-12-01

    High latitude soils and sediments often contain large quantities of methane as well as microbial communities capable of producing and consuming the methane. We studied the microbial communities collected from hydrate-bearing sediments on the Alaskan North Slope to determine how abiotic variables (e.g., grain size, hydrate presence, original depositional environment) may control the type and distribution of microbes in the sediments. The cores were acquired from sub-permafrost, Eocene (35-36 million years ago [MYA]) sediments laid down as a marine transgressive series within which hydrates are believed to have formed 1.5 MYA. Forty samples, eight of which originally contained hydrates, were acquired from depths of ca. 606-666 meters below land surface. Five samples from drilling fluids acquired from the same depth range were included in the analysis as a control for contamination during the drilling and handling of cores. DNA was extracted from the samples (typically <1 ng DNA/g sediment was recovered) and then amplified using polymerase chain reaction with primers specific for bacterial and archaeal 16S rDNA. Only bacterial DNA amplicons were detected. Terminal-restriction fragment length polymorphism (t-RFLP) was used to measure bacterial diversity in the respective samples. Non-metric multidimensional scaling (NMDS) was then used to determine the abiotic variables that may have influenced bacterial diversity. NMDS analysis revealed that sediment samples were distinct from those obtained from drilling fluids suggesting that the samples were not contaminated by the drilling fluids. All samples had evidence of microbial communities and sample depth, temperature, and hydrate presence appeared to have some influence on community diversity. Samples sharing these environmental parameters often shared common t-RFLP profiles. Further examination of selected samples using clone libraries should help to identify the key taxa present in these unique sediments and yield a

  18. Temperature and injection water source influence microbial community structure in four Alaskan North Slope hydrocarbon reservoirs

    PubMed Central

    Piceno, Yvette M.; Reid, Francine C.; Tom, Lauren M.; Conrad, Mark E.; Bill, Markus; Hubbard, Christopher G.; Fouke, Bruce W.; Graff, Craig J.; Han, Jiabin; Stringfellow, William T.; Hanlon, Jeremy S.; Hu, Ping; Hazen, Terry C.; Andersen, Gary L.

    2014-01-01

    A fundamental knowledge of microbial community structure in petroleum reservoirs can improve predictive modeling of these environments. We used hydrocarbon profiles, stable isotopes, and high-density DNA microarray analysis to characterize microbial communities in produced water from four Alaskan North Slope hydrocarbon reservoirs. Produced fluids from Schrader Bluff (24–27°C), Kuparuk (47–70°C), Sag River (80°C), and Ivishak (80–83°C) reservoirs were collected, with paired soured/non-soured wells sampled from Kuparuk and Ivishak. Chemical and stable isotope data suggested Schrader Bluff had substantial biogenic methane, whereas methane was mostly thermogenic in deeper reservoirs. Acetoclastic methanogens (Methanosaeta) were most prominent in Schrader Bluff samples, and the combined δD and δ13C values of methane also indicated acetoclastic methanogenesis could be a primary route for biogenic methane. Conversely, hydrogenotrophic methanogens (e.g., Methanobacteriaceae) and sulfide-producing Archaeoglobus and Thermococcus were more prominent in Kuparuk samples. Sulfide-producing microbes were detected in all reservoirs, uncoupled from souring status (e.g., the non-soured Kuparuk samples had higher relative abundances of many sulfate-reducers compared to the soured sample, suggesting sulfate-reducers may be living fermentatively/syntrophically when sulfate is limited). Sulfate abundance via long-term seawater injection resulted in greater relative abundances of Desulfonauticus, Desulfomicrobium, and Desulfuromonas in the soured Ivishak well compared to the non-soured well. In the non-soured Ivishak sample, several taxa affiliated with Thermoanaerobacter and Halomonas predominated. Archaea were not detected in the deepest reservoirs. Functional group taxa differed in relative abundance among reservoirs, likely reflecting differing thermal and/or geochemical influences. PMID:25147549

  19. Sarcocystis arctica (Apicomplexa: Sarcocystidae): ultrastructural description and its new host record, the Alaskan wolf (Canis lupus).

    PubMed

    Calero-Bernal, Rafael; Cerqueira-Cézar, Camila K; Verma, Shiv Kumar; Mowery, Joseph; Carmena, David; Beckmen, Kimberlee; Dubey, Jitender P

    2016-07-01

    Sarcocystis sarcocysts are common in muscles of herbivores but are rare in muscles of carnivores. Here, we report sarcocysts in the muscles of a gray wolf (Canis lupus) from Alaska, USA, for the first time. Sarcocysts extracted from the tongue of the wolf were up to 900 μm long and slender and appeared to have a relatively thin wall by light microscope. By transmission electron microscopy, the sarcocyst wall most closely resembled "type 9c," and had a wavy parasitophorous vacuolar membrane folded as pleomorphic villar protrusions (vp), with anastomoses of tips. The vp and the ground substance (gs) layer were smooth without tubules or granules. The gs was up to 2.0 μm thick. The total width of the wall including vp and the gs was 3.5 μm. The vp were up to 1.5 μm long. Mature sarcocysts contained numerous bradyzoites and few metrocytes. The bradyzoites were 9.5 μm long and 1.5 μm wide, and contained all organelles found in Sarcocystis bradyzoites with at least two rhoptries. Molecular characterization showed the highest identity for 18S rRNA, 28S rRNA, ITS-1, and cox1 sequences of Sarcocystis arctica of the Arctic fox (Vulpes lagopus) from Norway. The ultrastructure of S. arctica from the fox is unknown. Here, we provide ultrastructure of S. arctica from the Alaskan wolf for the first time. The definitive host of S. arctica remains unknown. PMID:27112760

  20. The State of Land Surface Model Uncertainty for the Alaskan Arctic

    NASA Astrophysics Data System (ADS)

    Fisher, J. B.; Sikka, M.; Oechel, W. C.; Koven, C. D.; Huntzinger, D. N.; Ahlstroem, A.; Arain, M. A.; Baker, I. T.; Chen, J. M.; Ciais, P.; Davidson, C. D.; Dietze, M. C.; ElMasri, B.; Hayes, D. J.; Huntingford, C.; Jain, A. K.; Lomas, M. R.; Poulter, B.; Price, D. T.; Sahoo, A. K.; Schaefer, K. M.; Tian, H.; Tomelleri, E.; Verbeeck, H.; Viovy, N.; Zeng, N.; Miller, C. E.

    2012-12-01

    Climate change is leading to a disproportionately large warming in the high northern latitudes, but the magnitude, and even sign, of the future carbon balance of the Arctic is highly uncertain. Using 27 land surface models, we provide a baseline of multi-model temporal and spatial variability for carbon, water, and energy stocks and fluxes across Alaska, USA, concentrating on the northern Arctic region. The models captured the diurnal cycle of the net ecosystem exchange (NEE) of CO2 at the Atqasuk and Barrow ground sites (multi-model mean vs. all site mean r2=0.92; RMSE=0.21 μmol CO2 m-2 s-1), though seasonally the models did worse (multi-model mean vs. all site mean r2=0.29; RMSE=0.45 μmol CO2 m-2 s-1). The spatial patterns in regional NEE varied widely between models with some models showing Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. The multi-model mean NEE for the Alaskan Arctic was -0.0120±0.0099 kg C m-2 y-1 in 2003 (i.e., significant carbon sink). The seasonal NEE for each model was generally similar across models (multi-model standard error: 0.01 kg C m-2 y-1). Total soil carbon stocks varied from 1.4-29.3 kg C m-2 across models, with a multi-model mean of 13.0±2.4 kg C m-2. Results for gross primary production (GPP), ecosystem respiration (Re), heterotrophic respiration (Rh), net primary production (NPP), soil moisture, soil temperature, active layer depth, latent heat flux (LE), and sensible heat flux (H) are provided as Supplementary Information.

  1. Effects of historical changes in climate on carbon storage in Alaskan arctic tundra

    SciTech Connect

    McKane, R.; Rastetter, E.; Shaver, G.; Nadelhoffer, K.; Giblin, A.; Laundre, J. ); Chapin, F.S. III )

    1994-06-01

    Surface air temperature in Arctic regions has increased since pre-industrial times, raising concerns that warmer and drier conditions have increased soil decomposition rates, thereby stimulating the release to the atmosphere of the large stores of C in arctic soils. We used a model (MBL-GEM) of ecosystem C and N dynamics to predict and analyze historical (1829 to 1990) changes in C storage in a tussock tundra ecosystem in Alaska. We calibrated the model by deriving a single parameter set that closely simulated responses to decade-long manipulations of nutrients, temperature, light, and atmospheric CO[sub 2]. Based on the combined effects of reconstructed historical changes in atmospheric CO[sub 2], mean growing-season temperature and two alternative soil moisture scenarios, the model predicts a [minus]3.0 + 2.1 percent change in ecosystem C from 1829 to 1990. These results are consistent with field evidence that historically recent changes in C storage of tussock tundra have been relatively small. However, the model also predicts that relatively large transient losses of ecosystem C(50 to 120 g m[sup [minus]2]yr[sup [minus]1]) may frequently have occurred since the late 1800s, with one of the largest simulated C losses of the 20th century occurring from 1988 to 1990 (85, 92, 61 g C m[sup [minus]2]yr[sup [minus]1], respectively). These simulated losses were at the low end of the range of losses measured in Alaskan tussock tundra from 1983 to 1990 (65 to 487 g C m[sup [minus]2]yr[sup [minus]1]), but nonetheless suggest that these recent losses may be transitory in nature.

  2. Payoffs and Pitfalls of a Minority Outreach Program: An Alaskan Example

    NASA Astrophysics Data System (ADS)

    Hanks, C. L.; Fowell, S. J.; Wartes, D.; Owens, G.

    2004-12-01

    The Rural Alaska Honors Institute (RAHI) is a summer bridging program for college-bound high school students from remote Alaskan communities. In the 20+ years since its initiation, more than 50% of RAHI graduates eventually obtained post-secondary degrees. The success of the RAHI program provides insights into how an outreach program can achieve its goals and avoid potential pitfalls. Instrumental to the success of the RAHI program are: longevity; small size (40-45 students per summer); support from the Alaska Native community; academic rigor; aggressive recruiting; establishment of a sense of community amongst participants; and individual mentoring and support. Potential pitfalls include: overextending the program to include too many students; failure to maintain academic rigor in all courses; recruitment of students and staff who do not embrace the program's methods and goals; and attempts to evaluate the program on the basis of short-term results. Alaska Natives in Geosciences introduces college-bound Alaska Native students to the geosciences by teaching a college-level introductory geoscience class as a RAHI elective. By collaborating with RAHI, Alaska Natives in Geosciences takes advantage of RAHI's effective recruitment efforts and proven mentoring program. However, maintaining scientific rigor has been difficult due to large differences in the students' scientific backgrounds, the demands of other courses in the RAHI program and the brevity of the summer session. Immediate post-course survey responses suggest that many RAHI students thought the geoscience class was interesting but too difficult and much too time-consuming. However, surveys of RAHI geoscience students a year later suggest that many found the course a very positive experience. An unanticipated result was that RAHI students who did not take the class also gained some insight into the geosciences.

  3. Recovery of plant biomass and soil N cycling in Alaskan tundra following an unusual fire

    NASA Astrophysics Data System (ADS)

    Bret-Harte, M. S.; Mack, M. C.; Huebner, D. C.; Johnston, M.; Shaver, G. R.

    2012-12-01

    Climate warming is likely to increase the frequency of disturbances in the Arctic. The Anaktuvuk River fire of 2007 burned 1039 km2 of northern Alaskan tundra; this was unprecedented for this vegetation, which is clonal, slow-growing, and long-lived. We harvested plant biomass and soils from severely and moderately burned areas and controls in 2011 to assess recovery of plant productivity and soil N cycling four years after the fire. Biomass of vascular plants had recovered to nearly control levels in moderately burned areas, due primarily to resprouting by graminoids, particularly Eriophorum vaginatum. Graminoid biomass was actually greater in moderately burned tundra than in unburned tundra. Deciduous shrub and evergreen shrub biomass in moderately burned tundra was approximately half that seen in unburned tundra, but non-vascular plant biomass was much less, so that total aboveground biomass in moderately burned tundra had not returned to control levels. Severely burned tundra had less of all components of the community than in moderately burned tundra, except that there was higher biomass of non-vascular plants, due to colonization by fire-following liverworts and mosses. Productivity of vascular plants was similar in unburned and severely burned tundra plots, and higher in moderately burned plots, due in part to higher soil N availability. Recovery of plant biomass was largely due to resprouting of species that survived the fire, though numerous seedlings were seen. Biomass of vascular plants has recovered rapidly in the moderately burned sites, while severely burned sites and nonvascular plants are recovering more slowly, but the relative abundance of different species differs from unburned tundra. The relationship between spectral indices (NDVI, EVI-2) collected at the plot level and either biomass or NPP varied with burn category, which may complicate assessments of NPP by remote sensing following fire.

  4. An estimate of carbon emissions from 2004 wildfires across Alaskan Yukon River Basin

    USGS Publications Warehouse

    Tan, Z.; Tieszen, L.L.; Zhu, Z.; Liu, S.; Howard, S.M.

    2007-01-01

    Background: Wildfires are an increasingly important component of the forces that drive the global carbon (C) cycle and climate change as progressive warming is expected in boreal areas. This study estimated C emissions from the wildfires across the Alaskan Yukon River Basin in 2004. We spatially related the firescars to land cover types and defined the C fractions of aboveground biomass and the ground layer (referring to the top 15 cm organic soil layer only in this paper) consumed in association with land cover types, soil drainage classes, and the C stocks in the ground layer. Results: The fires led to a burned area of 26,500 km2 and resulted in the total C emission of 81.1 ?? 13.6 Tg (Tg, Teragram; 1 Tg = 1012g) or 3.1 ?? 0.7 kg C m-2 burned. Of the total C emission, about 73% and 27% could be attributed to the consumption of the ground layer and aboveground biomass, respectively. Conclusion: The predominant contribution of the ground layer to the total C emission implies the importance of ground fuel management to the control of wildfires and mitigation of C emissions. The magnitude of the total C emission depends on fire extent, while the C loss in kg C m-2 burned is affected strongly by the ground layer and soil drainage condition. The significant reduction in the ground layer by large fires may result in profound impacts on boreal ecosystem services with an increase in feedbacks between wildfires and climate change. ?? 2007 Tan et al; licensee BioMed Central Ltd.

  5. Geographic and seasonal variation of dissolved methane and aerobic methane oxidation in Alaskan lakes

    NASA Astrophysics Data System (ADS)

    Martinez-Cruz, K.; Sepulveda-Jauregui, A.; Anthony, K. Walter; Thalasso, F.

    2015-08-01

    Methanotrophic bacteria play an important role oxidizing a significant fraction of methane (CH4) produced in lakes. Aerobic CH4 oxidation depends mainly on lake CH4 and oxygen (O2) concentrations, in such a manner that higher MO rates are usually found at the oxic/anoxic interface, where both molecules are present. MO also depends on temperature, and via methanogenesis, on organic carbon input to lakes, including from thawing permafrost in thermokarst (thaw)-affected lakes. Given the large variability in these environmental factors, CH4 oxidation is expected to be subject to large seasonal and geographic variations, which have been scarcely reported in the literature. In the present study, we measured CH4 oxidation rates in 30 Alaskan lakes along a north-south latitudinal transect during winter and summer with a new field laser spectroscopy method. Additionally, we measured dissolved CH4 and O2 concentrations. We found that in the winter, aerobic CH4 oxidation was mainly controlled by the dissolved O2 concentration, while in the summer it was controlled primarily by the CH4 concentration, which was scarce compared to dissolved O2. The permafrost environment of the lakes was identified as another key factor. Thermokarst (thaw) lakes formed in yedoma-type permafrost had significantly higher CH4 oxidation rates compared to other thermokarst and non-thermokarst lakes formed in non-yedoma permafrost environments. As thermokarst lakes formed in yedoma-type permafrost have been identified to receive large quantities of terrestrial organic carbon from thaw and subsidence of the surrounding landscape into the lake, confirming the strong coupling between terrestrial and aquatic habitats and its influence on CH4 cycling.

  6. Temperature calibration and phylogenetically distinct distributions for freshwater alkenones: Evidence from northern Alaskan lakes

    NASA Astrophysics Data System (ADS)

    Longo, William M.; Theroux, Susanna; Giblin, Anne E.; Zheng, Yinsui; Dillon, James T.; Huang, Yongsong

    2016-05-01

    Alkenones are a class of unsaturated long-chain ketone biomarkers that have been used to reconstruct sea surface temperature and, more recently, continental temperature, by way of alkenone unsaturation indices (e.g. U37K and U37K‧). Alkenones are frequently found in brackish and saline lakes, however species effects confound temperature reconstructions when multiple alkenone-producing species with different temperature responses are present. Interestingly, available genetic data indicate that numerous freshwater lakes host a distinct phylotype of alkenone-producing haptophyte algae (the Group I or Greenland phylotype), providing evidence that species effects may be diminished in freshwater lakes. These findings encourage further investigation of alkenone paleotemperature proxies in freshwater systems. Here, we investigated lakes from northern Alaska (n = 35) and show that alkenones commonly occurred in freshwater lakes, where they featured distinct distributions, characterized by dominant C37:4 alkenones and a series of tri-unsaturated alkenone isomers. The distributions were characteristic of Group I-type alkenone distributions previously identified in Greenland and North America. Our analysis of suspended particulate matter from Toolik Lake (68° 38‧N, 149° 36‧W) yielded the first in situ freshwater U37K calibration (U37K = 0.021 * T - 0.68; r2 = 0.85; n = 52; RMSE = ±1.37 °C). We explored the environmental significance of the tri-unsaturated isomers using our northern Alaskan lakes dataset in conjunction with new data from haptophyte cultures and Canadian surface sediments. Our results show that these temperature-sensitive isomers are biomarkers for the Group I phylotype and indicators of multiple-species effects. Together, these findings highlight freshwater lakes as valuable targets for continental alkenone-based paleotemperature reconstructions and demonstrate the significance of the recently discovered tri-unsaturated isomers.

  7. Alaskan transect links Holocene carbon shifts to peatland paleoecology and paleoclimate

    NASA Astrophysics Data System (ADS)

    Peteet, D. M.; Nichols, J. E.; Andreev, A.; McGeachy, A.; Perez, M.

    2011-12-01

    Arctic and subarctic peatlands are highly sensitive to climate shifts, and greenhouse warming is greatest at high latitudes. As high latitudes warm and peatlands provide positive and negative feedbacks in carbon sequestration, the paleo-perspective becomes critical in assessing future peatland stocks. We target a north-south (temperature) and east-west (moisture) transect of Alaskan peatlands using pollen and spores, plant macrofossils, charcoal, stable isotopes, and C/N coupled with carbon to explore the relationship of climate and vegetation shifts to carbon storage through time. Since deglaciation, peatlands have developed in a variety of maritime and continental subarctic and arctic environments with vegetation ranging from fens to bogs. Factors affecting the net carbon storage (productivity and decomposition) include the vegetation type, precipitation, temperature, bryophyte component, seasonality, snow history, fire history, and permafrost. New paleoecological records from three Holocene peatlands, each spanning at least 9000 years, include a continental boreal forest site, Goldmine Bog, Fairbanks, (65°N, 147°W), and maritime sites including Phalarope Bog, Kodiak (57°N, 154°W), and Bear Bog, Cordova (60°N, 145°W). Major shifts in moisture and temperature are evident throughout the Holocene from our multiproxy investigations of each site. Our data address several questions about subarctic/arctic carbon storage and climate, such as whether bogs or fens sequester more carbon, as this topic is intensely debated in the current literature. We also compare shifts in inferred moisture and temperature with carbon storage at each site, and with other coastal and interior sites for a fuller understanding of changes in the climate of this important region.

  8. Alaskan Husky encephalopathy--a canine neurodegenerative disorder resembling subacute necrotizing encephalomyelopathy (Leigh syndrome).

    PubMed

    Brenner, O; Wakshlag, J J; Summers, B A; de Lahunta, A

    2000-07-01

    The gross and histopathological findings in the brain and spinal cord of five Alaskan Husky dogs with a novel incapacitating and ultimately fatal familial and presumed hereditary neurodegenerative disorder are described. Four dogs presented with neurological deficits before the age of 1 year (7-11 months) and one animal at 2.5 years old. Clinical signs in all dogs were of acute onset and included ataxia, seizures, behavioral abnormalities, blindness, facial hypalgesia and difficulties in prehension of food. In animals allowed to survive, the disease was static but with frequent recurrences. Pathological findings were limited to the central nervous system. Grossly visible bilateral and symmetrical cavitated foci were consistently present in the thalamus with variable extension into the caudal brain stem. Microscopic lesions were more widespread and included foci of bilateral and symmetrical degeneration in the basal nuclei, midbrain, pons and medulla, as well as multifocal lesions at the base of sulci in the cerebral cortex and in the gray matter of cerebellar folia in the ventral vermis. Neuronal loss with concomitant neuronal sparing, spongiosis, vascular hypertrophy and hyperplasia, gliosis, cavitation and transient mixed inflammatory infiltration were the main histopathological findings. In addition, a population of reactive gemistocytic astrocytes with prominent cytoplasmic vacuolation was noted in the thalamus. Lesions of this nature in this distribution within the neuroaxis have not been reported in dogs. The neuropathological findings resemble Leigh's disease/subacute necrotizing encephalomyelopathy of man. Neuronal sparing in conjunction with apparently transient astrocytic vacuolation point to the possible pathogenetic role of astrocytes in the evolution of these lesions. An inherited metabolic derangement of unknown nature is postulated as the cause of this breed-specific disorder.

  9. Wetting behavior of alternative solder alloys

    SciTech Connect

    Hosking, F.M.; Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.

    1993-07-01

    Recent economic and environmental issues have stimulated interest in solder alloys other than the traditional Sn-Pb eutectic or near eutectic composition. Preliminary evaluations suggest that several of these alloys approach the baseline properties (wetting, mechanical, thermal, and electrical) of the Sn-Pb solders. Final alloy acceptance will require major revisions to existing industrial and military soldering specifications. Bulk alloy and solder joint properties are consequently being investigated to validate their producibility and reliability. The work reported in this paper examines the wetting behavior of several of the more promising commercial alloys on copper substrates. Solder wettability was determined by the meniscometer and wetting balance techniques. The wetting results suggest that several of the alternative solders would satisfy pretinning and surface mount soldering applications. Their use on plated through hole technology might be more difficult since the alloys generally did not spread or flow as well as the 60Sn-40Pb solder.

  10. National Ignition Facility wet weather construction plan

    SciTech Connect

    Kugler, A N

    1998-01-01

    This report presents a wet weather construction plan for the National Ignition Facility (NIF) construction project. Construction of the NIF commenced in mid- 1997, and excavation of the site was completed in the fall. Preparations for placing concrete foundations began in the fall, and above normal rainfall is expected over the tinter. Heavy rainfall in late November impacted foundation construction, and a wet weather construction plan was determined to be needed. This wet weather constiction plan recommends a strategy, techniques and management practices to prepare and protect the site corn wet weather effects and allow construction work to proceed. It is intended that information in this plan be incorporated in the Stormwater Pollution Prevention Plan (SWPPP) as warranted.

  11. A WET TALE: TOXICITY OF COMPLEX EFFLUENTS

    EPA Science Inventory

    This course covers standards, regulations, policy, guidance and technical aspects of implementing the whole effluent toxicity program. The curriculum incorporates rationale and information on WET test requirements from USEPA documents, such as the Technical Support Document for W...

  12. Wetting of a Chemically Heterogeneous Surface

    SciTech Connect

    Frink, L.J.D.; Salinger, A.G.

    1998-11-20

    Theories for inhomogeneous fluids have focused in recent years on wetting, capillary conden- sation, and solvation forces for model systems where the surface(s) is(are) smooth homogeneous parallel plates, cylinders, or spherical drops. Unfortunately natural systems are more likely to be hetaogeneous both in surt%ce shape and surface chemistry. In this paper we discuss the conse- quences of chemical heterogeneity on wetting. Specifically, a 2-dimensional implementation of a nonlocal density functional theory is solved for a striped surface model. Both the strength and range of the heterogeneity are varied. Contact angles are calculated, and phase transitions (both the wetting transition and a local layering transition) are located. The wetting properties of the surface ase shown to be strongly dependent on the nature of the surface heterogeneity. In addition highly ordered nanoscopic phases are found, and the operational limits for formation of ordered or crystalline phases of nanoscopic extent are discussed.

  13. Reducing the atmospheric impact of wet slaking

    SciTech Connect

    B.D. Zubitskii; G.V. Ushakov; B.G. Tryasunov; A.G.Ushakov

    2009-05-15

    Means of reducing the atmospheric emissions due to the wet slaking of coke are considered. One option, investigated here, is to remove residual active silt and organic compounds from the biologically purified wastewater sent for slaking, by coagulation and flocculation.

  14. Critical point wetting drop tower experiment

    NASA Technical Reports Server (NTRS)

    Kaukler, W. F.; Tcherneshoff, L. M.; Straits, S. R.

    1984-01-01

    Preliminary results for the Critical Point Wetting CPW Drop Tower Experiment are produced with immiscible systems. Much of the observed phenomena conformed to the anticipated behavior. More drops will be needed to test the CPW theory with these immiscible systems.

  15. Chlorine Disinfection of Wet Weather Managed Flows

    EPA Science Inventory

    Blending is a practice used in the wastewater industry to deal with wet weather events when the hydraulic capacity of the treatment facility could be compromised. Blending consists of primary wastewater treatment plant effluent, partially bypassing secondary treatment, and then ...

  16. Snow wetness measurements for melt forecasting

    NASA Technical Reports Server (NTRS)

    Linlor, W. I.; Clapp, F. D.; Meier, M. F.; Smith, J. L.

    1975-01-01

    A microwave technique for directly measuring snow pack wetness in remote installations is described. The technique, which uses satellite telemetry for data gathering, is based on the attenuation of a microwave beam in transmission through snow.

  17. Structure of Wet Specimens in Electron Microscopy

    ERIC Educational Resources Information Center

    Parsons, D. F.

    1974-01-01

    Discussed are past work and recent advances in the use of electron microscopes for viewing structures immersed in gas and liquid. Improved environmental chambers make it possible to examine wet specimens easily. (Author/RH)

  18. Wetting on flexible hydrophilic pillar-arrays

    PubMed Central

    Yuan, Quanzi; Zhao, Ya-Pu

    2013-01-01

    Dynamic wetting on the flexible hydrophilic pillar-arrays is studied using large scale molecular dynamics simulations. For the first time, the combined effect of the surface topology, the intrinsic wettability and the elasticity of a solid on the wetting process is taken into consideration. The direction-dependent dynamics of both liquid and pillars, especially at the moving contact line (MCL), is revealed at atomic level. The flexible pillars accelerate the liquid when the liquid approaches, and pin the liquid when the liquid passes. The liquid deforms the pillars, resulting energy dissipation at the MCL. Scaling analysis is performed based on molecular kinetic theory and validated by our simulations. Our results may expand our knowledge of wetting on pillars and assisting the future design of active control of wetting in practical applications. PMID:23736041

  19. Making and Experimenting with a Wet Cell.

    ERIC Educational Resources Information Center

    George, Arnold

    1993-01-01

    Presents an activity that demonstrates the physical and chemical changes that occur during the operation of a wet cell battery as it produces an electrical current. Provides instructions for the lesson. (MDH)

  20. ESTIMATING URBAN WET-WEATHER POLLUTANT LOADING

    EPA Science Inventory

    This paper presents procedures for estimating pollutant loads in urban watersheds emanating from wet-weather flow discharge. Equations for pollutant loading estimates will focus on the effects of wastewater characteristics, sewer flow carrying velocity, and sewer-solids depositi...

  1. 7 CFR 51.491 - Wet slip.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... time of packing in which the stem scar is abnormally large, excessively wet and slippery, yields to slight pressure, and is frequently accompanied by fresh radial growth cracks at the edge of the stem scar....

  2. 7 CFR 51.491 - Wet slip.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... time of packing in which the stem scar is abnormally large, excessively wet and slippery, yields to slight pressure, and is frequently accompanied by fresh radial growth cracks at the edge of the stem scar....

  3. 7 CFR 51.491 - Wet slip.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... time of packing in which the stem scar is abnormally large, excessively wet and slippery, yields to slight pressure, and is frequently accompanied by fresh radial growth cracks at the edge of the stem scar....

  4. Wet/dry cooling tower and method

    DOEpatents

    Glicksman, Leon R.; Rohsenow, Warren R.

    1981-01-01

    A wet/dry cooling tower wherein a liquid to-be-cooled is flowed along channels of a corrugated open surface or the like, which surface is swept by cooling air. The amount of the surface covered by the liquid is kept small compared to the dry part thereof so that said dry part acts as a fin for the wet part for heat dissipation.

  5. Complete wetting of graphene by biological lipids

    NASA Astrophysics Data System (ADS)

    Luan, Binquan; Huynh, Tien; Zhou, Ruhong

    2016-03-01

    Graphene nanosheets have been demonstrated to extract large amounts of lipid molecules directly out of the cell membrane of bacteria and thus cause serious damage to the cell's integrity. This interesting phenomenon, however, is so far not well understood theoretically. Here through extensive molecular dynamics simulations and theoretical analyses, we show that this phenomenon can be categorized as a complete wetting of graphene by membrane lipids in water. A wetting-based theory was utilized to associate the free energy change during the microscopic extraction of a lipid with the spreading parameter for the macroscopic wetting. With a customized thermodynamic cycle for detailed energetics, we show that the dispersive adhesion between graphene and lipids plays a dominant role during this extraction as manifested by the curved graphene. Our simulation results suggest that biological lipids can completely wet the concave, flat or even convex (with a small curvature) surface of a graphene sheet.Graphene nanosheets have been demonstrated to extract large amounts of lipid molecules directly out of the cell membrane of bacteria and thus cause serious damage to the cell's integrity. This interesting phenomenon, however, is so far not well understood theoretically. Here through extensive molecular dynamics simulations and theoretical analyses, we show that this phenomenon can be categorized as a complete wetting of graphene by membrane lipids in water. A wetting-based theory was utilized to associate the free energy change during the microscopic extraction of a lipid with the spreading parameter for the macroscopic wetting. With a customized thermodynamic cycle for detailed energetics, we show that the dispersive adhesion between graphene and lipids plays a dominant role during this extraction as manifested by the curved graphene. Our simulation results suggest that biological lipids can completely wet the concave, flat or even convex (with a small curvature) surface of a

  6. Recent developments in wet carbonization of peat

    SciTech Connect

    Rue, D.M.; Mensinger, M.C.; Srivastava, V.J.

    1986-08-01

    Wet carbonization is a generic term for a thermal beneficiation process in which wet peat is heated to temperatures of 150 to 325/sup 0/C at elevated pressures so that water present remains in liquid form. Wet carbonization produces a solid product with a higher heating value than raw peat. Wet-carbonized peat can be mechanically dewatered to a significantly lower moisture content than raw peat. A continuous-flow Process Research Unit (PRU), capable of processing 375 kg/h of peat slurry at temperatures and pressures up to 290/sup 0/C and 7.60 MPa, respectively, was used to study the effect of wet-carbonization operating conditions on the peat. Thirteen tests were made with peats from Minnesota and Maine. For the Minnesota peat tests, the feed slurry solids concentration ranged from 6.1 to 13.7%. The average reactor operating temperatures and residence times ranged from 175 to 260/sup 0/C and 1 to 60 minutes, respectively. The heating value enhancement of the wet-carbonized peats was as high as 21%, and the moisture content of mechanically-dewatered wet-carbonized peat was as low as 39% (compared with >65% for raw peat). A bench-scale, continuous two-phase anaerobic digestion system to recover energy and to treat wet-carbonization effluent water was designed, fabricated, and tested with effluent water from the PRU tests. At a short hydraulic retention time of 2.9 days, the system provided COD and BOD/sub 5/ removal efficiencies of 56 and 75%, respectively. The methane yield was approximately 86% of the average ultimate biodegradable yield. 6 refs., 10 figs., 2 tabs.

  7. Leaf wetness distribution within a potato crop

    NASA Astrophysics Data System (ADS)

    Heusinkveld, B. G.

    2010-07-01

    The Netherlands has a mild maritime climate and therefore the major interest in leaf wetness is associated with foliar plant diseases. During moist micrometeorological conditions (i.e. dew, fog, rain), foliar fungal diseases may develop quickly and thereby destroy a crop quickly. Potato crop monocultures covering several hectares are especially vulnerable to such diseases. Therefore understanding and predicting leaf wetness in potato crops is crucial in crop disease control strategies. A field experiment was carried out in a large homogeneous potato crop in the Netherlands during the growing season of 2008. Two innovative sensor networks were installed as a 3 by 3 grid at 3 heights covering an area of about 2 hectares within two larger potato crops. One crop was located on a sandy soil and one crop on a sandy peat soil. In most cases leaf wetting starts in the top layer and then progresses downward. Leaf drying takes place in the same order after sunrise. A canopy dew simulation model was applied to simulate spatial leaf wetness distribution. The dew model is based on an energy balance model. The model can be run using information on the above-canopy wind speed, air temperature, humidity, net radiation and within canopy air temperature, humidity and soil moisture content and temperature conditions. Rainfall was accounted for by applying an interception model. The results of the dew model agreed well with the leaf wetness sensors if all local conditions were considered. The measurements show that the spatial correlation of leaf wetness decreases downward.

  8. The footprint of Alaskan tundra fires during the past half-century: implications for surface properties and radiative forcing

    USGS Publications Warehouse

    Rocha, Adrian V.; Loranty, Michael M.; Higuera, Phil E.; Mack, Michelle C.; Hu, Feng Sheng; Jones, Benjamin M.; Breen, Amy L.; Rastetter, Edward B.; Goetz, Scott J.; Shaver, Gus R.

    2012-01-01

    Recent large and frequent fires above the Alaskan arctic circle have forced a reassessment of the ecological and climatological importance of fire in arctic tundra ecosystems. Here we provide a general overview of the occurrence, distribution, and ecological and climate implications of Alaskan tundra fires over the past half-century using spatially explicit climate, fire, vegetation and remote sensing datasets for Alaska. Our analyses highlight the importance of vegetation biomass and environmental conditions in regulating tundra burning, and demonstrate that most tundra ecosystems are susceptible to burn, providing the environmental conditions are right. Over the past two decades, fire perimeters above the arctic circle have increased in size and importance, especially on the North Slope, indicating that future wildfire projections should account for fire regime changes in these regions. Remote sensing data and a literature review of thaw depths indicate that tundra fires have both positive and negative implications for climatic feedbacks including a decadal increase in albedo radiative forcing immediately after a fire, a stimulation of surface greenness and a persistent long-term (>10 year) increase in thaw depth. In order to address the future impact of tundra fires on climate, a better understanding of the control of tundra fire occurrence as well as the long-term impacts on ecosystem carbon cycling will be required.

  9. Effect of the long-term elevation of CO sub 2 concentration in the field on the quantum yield of photosynthesis of the C sub 3 sedge, Scirpus olneyi

    SciTech Connect

    Long, S.P. ); Drake, B.G. )

    1991-05-01

    CO{sub 2} concentration was elevated throughout 3 years around stands of the C{sub 3} sedge Scirpus olneyi on a tidal marsh of the Chesapeake Bay. The hypothesis that tissues developed in an elevated CO{sub 2} atmosphere will show an acclimatory decrease in photosynthetic capacity under light-limiting conditions was examined. The absorbed light quantum yield of CO{sub 2} uptake ({phi}{sub abs}) and the efficiency of photosystem II photochemistry were determined for plants which had developed in open top chambers with CO{sub 2} concentrations in air of 680 micromoles per mole, and of 351 micromoles per mole as controls. When measured in an atmosphere with 10 millimoles per mole O{sub 2} to suppress photorespiration, shoots showed a {phi}{sub abs} of 0.093 {plus minus} 0.003, with no statistically significant difference between shoots grown in elevated or control CO{sub 2} concentration. Efficiency of photosystem II photochemistry was also unchanged by development in an elevated CO{sub 2} atmosphere. Shoots grown and measured in 680 micromoles per mole of CO{sub 2} in air showed a {phi}{sub abs} of 0.078 {plus minus} 0.004 compared with 0.065 {plus minus} for leaves grown and measured in 351 micromoles per mole CO{sub 2} in air; a highly significant increase. In accordance with the change in {phi}{sub abs}, the light compensation point of photosynthesis decreased from 51 {plus minus} 3 to 31 {plus minus} 3 micromoles per square meter per second for stems grown and measured in 351 and 680 micromoles per mole of CO{sub 2} in air, respectively.

  10. Tissue Distribution of Polychlorinated Biphenyls and Organochlorine Pesticides and Potential Toxicity to Alaskan Northern Fur Seals Assessed Using PCBs Congener Specific Mode of Action Schemes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The concentrations of 145 polychlorinated biphenyl (PCB) congeners were measured using gas chromatography-ion trap mass spectrometry in 8 different tissues (blubber, brain, heart, kidney, liver, lung, muscle, and reproductive tissues) of 10 Alaskan northern fur seals. The mean concentrations of bot...

  11. Apolipoprotein E isoforms 3/3 and 3/4 differentially interact with circulating stearic, palmitic, and oleic fatty acids and lipid levels in Alaskan Natives.

    PubMed

    Castellanos-Tapia, Lyssia; López-Alvarenga, Juan Carlos; Ebbesson, Sven O E; Ebbesson, Lars O E; Tejero, M Elizabeth

    2015-04-01

    Lifestyle changes in Alaskan Natives have been related to the increase of cardiovascular disease and metabolic syndrome in the last decades. Variation of the apolipoprotein E (Apo E) genotype may contribute to the diverse response to diet in lipid metabolism and influence the association between fatty acids in plasma and risk factors for cardiovascular disease. The aim of this investigation was to analyze the interaction between Apo E isoforms and plasma fatty acids, influencing phenotypes related to metabolic diseases in Alaskan Natives. A sample of 427 adult Siberian Yupik Alaskan Natives was included. Fasting glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, Apo A1, and Apo B plasma concentrations were measured using reference methods. Concentrations of 13 fatty acids in fasting plasma were analyzed by gas chromatography, and Apo E variants were identified. Analyses of covariance were conducted to identify Apo E isoform and fatty acid main effects and multiplicative interactions. The means for body mass index and age were 26 ± 5.2 and 47 ± 1.5, respectively. Significant main effects were observed for variation in Apo E and different fatty acids influencing Apo B levels, triglycerides, and total cholesterol. Significant interactions were found between Apo E isoform and selected fatty acids influencing total cholesterol, triglycerides, and Apo B concentrations. In summary, Apo E3/3 and 3/4 isoforms had significant interactions with circulating levels of stearic, palmitic, oleic fatty acids, and phenotypes of lipid metabolism in Alaskan Natives.

  12. A Report and Basic Proposal to Provide Alaskan Manpower Entry into the Pipeline and Related Construction Skills via Technical Training, Immediate and Intermediate.

    ERIC Educational Resources Information Center

    Bland, Laurel L.

    To make policy makers and others more aware of possibilities for utilizing Alaskan manpower, information has been gathered on the manpower demand to construct the proposed 800 mile Alaska oil pipeline and its supporting system. The recruitment and training of chronically unemployed or underemployed workers (largely Eskimos and Indians) is being…

  13. Alaskan Superintendent Turnover: Is There a Correlation between Anticipated Turnover and the Organizational Culture of School Boards in the State of Alaska

    ERIC Educational Resources Information Center

    Herbert, David M. Q.

    2012-01-01

    The purpose of this study is to determine if a particular type of school board culture is predictive of Alaskan public school superintendents' intention to leave their positions. Cameron and Quinn's four types of organizational culture--hierarchy, market, clan, and adhocracy--serve as the model for the study, which surveyed Alaska's…

  14. Partial replacement of menhaden oil with Alaskan pollack viceral meal in striped bass Morone saxatilis and sunshine bass M. chrysops X M. saxatilis diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recovery of waste by-products from the Alaskan fishery and use in fish feeds can potentially reduce pressure on fish harvested for animal feed applications. However, little data exist evaluating these by-products in moronid diets. Striped bass and sunshine bass growth, body composition, and imm...

  15. 33 CFR 334.1300 - Blying Sound area, Gulf of Alaska, Alaska; air-to-air gunnery practice area, Alaskan Air Command...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Blying Sound area, Gulf of Alaska, Alaska; air-to-air gunnery practice area, Alaskan Air Command, U.S. Air Force. 334.1300 Section 334.1300... AND RESTRICTED AREA REGULATIONS § 334.1300 Blying Sound area, Gulf of Alaska, Alaska;...

  16. 33 CFR 334.1300 - Blying Sound area, Gulf of Alaska, Alaska; air-to-air gunnery practice area, Alaskan Air Command...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Blying Sound area, Gulf of Alaska, Alaska; air-to-air gunnery practice area, Alaskan Air Command, U.S. Air Force. 334.1300 Section 334.1300... AND RESTRICTED AREA REGULATIONS § 334.1300 Blying Sound area, Gulf of Alaska, Alaska;...

  17. Use of fish hydrolysates and fishmeal by-products of the Alaskan fishing industry in diets for Pacific white shrimp (Litopenaeus vannamei)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The suitability of four fish hydrolysates and two fishmeals derived from by-products of the Alaskan fishing industry, as menhaden fishmeal replacements in shrimp diets was determined. A control diet (30% crude protein and 8.5% crude lipid) was produced with menhaden meal (13% of diet). Experimental ...

  18. Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 through December 31, 2005

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Estes, Steve; McNutt, Stephen R.

    2006-01-01

    Summary: The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988 (Figure 1). The primary objectives of the seismic program are the real-time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents calculated earthquake hypocenters and seismic phase arrival data, and details changes in the seismic monitoring program for the period January 1 through December 31, 2005. The AVO seismograph network was used to monitor the seismic activity at thirty-two volcanoes within Alaska in 2005 (Figure 1). The network was augmented by two new subnetworks to monitor the Semisopochnoi Island volcanoes and Little Sitkin Volcano. Seismicity at these volcanoes was still being studied at the end of 2005 and has not yet been added to the list of permanently monitored volcanoes in the AVO weekly update. Following an extended period of monitoring to determine the background seismicity at the Mount Peulik, Ukinrek Maars, and Korovin Volcano, formal monitoring of these volcanoes began in 2005. AVO located 9,012 earthquakes in 2005. Monitoring highlights in 2005 include: (1) seismicity at Mount Spurr remaining above background, starting in February 2004, through the end of the year and into 2006; (2) an increase in seismicity at Augustine Volcano starting in May 2005, and continuing through the end of the year into 2006; (3) volcanic tremor and seismicity related to low-level strombolian activity at Mount Veniaminof in January to March and September; and (4) a seismic swarm at Tanaga Volcano in October and November. This catalog includes: (1) descriptions and locations of seismic instrumentation deployed in the field in 2005

  19. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2003

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sanchez, John J.; McNutt, Stephen R.; Estes, Steve; Paskievitch, John

    2004-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of this program are the near real time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the calculated earthquake hypocenter and phase arrival data, and changes in the seismic monitoring program for the period January 1 through December 31, 2003. The AVO seismograph network was used to monitor the seismic activity at twenty-seven volcanoes within Alaska in 2003. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai volcanic cluster (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Okmok Caldera, Great Sitkin Volcano, Kanaga Volcano, Tanaga Volcano, and Mount Gareloi. Monitoring highlights in 2003 include: continuing elevated seismicity at Mount Veniaminof in January-April (volcanic unrest began in August 2002), volcanogenic seismic swarms at Shishaldin Volcano throughout the year, and low-level tremor at Okmok Caldera throughout the year. Instrumentation and data acquisition highlights in 2003 were the installation of subnetworks on Tanaga and Gareloi Islands, the installation of broadband installations on Akutan Volcano and Okmok Caldera, and the establishment of telemetry for the Okmok Caldera subnetwork. AVO located 3911 earthquakes in 2003. This catalog includes: (1) a description of instruments deployed in the field and their locations; (2) a

  20. Catalog of earthquake hypocenters at Alaskan volcanoes: January 1 through December 31, 2003

    USGS Publications Warehouse

    Dixon, James P.; Stihler, Scott D.; Power, John A.; Tytgat, Guy; Moran, Seth C.; Sanchez, John J.; McNutt, Stephen R.; Estes, Steve; Paskievitch, John

    2004-01-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, has maintained seismic monitoring networks at historically active volcanoes in Alaska since 1988. The primary objectives of this program are the near real time seismic monitoring of active, potentially hazardous, Alaskan volcanoes and the investigation of seismic processes associated with active volcanism. This catalog presents the calculated earthquake hypocenter and phase arrival data, and changes in the seismic monitoring program for the period January 1 through December 31, 2003.The AVO seismograph network was used to monitor the seismic activity at twenty-seven volcanoes within Alaska in 2003. These include Mount Wrangell, Mount Spurr, Redoubt Volcano, Iliamna Volcano, Augustine Volcano, Katmai volcanic cluster (Snowy Mountain, Mount Griggs, Mount Katmai, Novarupta, Trident Volcano, Mount Mageik, Mount Martin), Aniakchak Crater, Mount Veniaminof, Pavlof Volcano, Mount Dutton, Isanotski Peaks, Shishaldin Volcano, Fisher Caldera, Westdahl Peak, Akutan Peak, Makushin Volcano, Okmok Caldera, Great Sitkin Volcano, Kanaga Volcano, Tanaga Volcano, and Mount Gareloi. Monitoring highlights in 2003 include: continuing elevated seismicity at Mount Veniaminof in January-April (volcanic unrest began in August 2002), volcanogenic seismic swarms at Shishaldin Volcano throughout the year, and low-level tremor at Okmok Caldera throughout the year. Instrumentation and data acquisition highlights in 2003 were the installation of subnetworks on Tanaga and Gareloi Islands, the installation of broadband installations on Akutan Volcano and Okmok Caldera, and the establishment of telemetry for the Okmok Caldera subnetwork. AVO located 3911 earthquakes in 2003.This catalog includes: (1) a description of instruments deployed in the field and their locations; (2) a