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Sample records for kenai fjords alaska

  1. Status and distribution of the Kittlitz's murrelet Brachyramphus brevirostris in Kenai Fjords, Alaska

    USGS Publications Warehouse

    Arimitsu, M.; Piatt, J.F.; Romano, Marc D.; van Pelt, Thomas I.

    2011-01-01

    The Kittlitz's Murrelet Brachyramphus brevirostris is a candidate species for listing under the US Endangered Species Act because of its apparent declines within core population areas of coastal Alaska. During the summers of 2006-2008, we conducted surveys in marine waters adjacent to Kenai Fjords National Park, Alaska, to estimate the current population size of Kittlitz's and Marbled murrelets B. marmoratus and examine seasonal variability in distribution within coastal fjords. We also evaluated historical data to estimate trend. Based on an average of point estimates, we find the recent population (95% CI) of Kittlitz's Murrelet to be 716 (353-1080) individuals, that of Marbled Murrelet to be 6690 (5427-7953) individuals, and all Brachyramphus murrelets combined to number 8186 (6978-9393) birds. Within-season density estimates showed Kittlitz's Murrelets generally increased between June and July, but dispersed rapidly by August, while Marbled Murrelets generally increased throughout the summer. Trends in Kittlitz's and Marbled murrelet populations were difficult to assess with confidence. Methods for counting or sampling murrelets varied in early decades of study, while in later years there is uncertainty due to highly variable counts among years, which may be due in part to timing of surveys relative to the spring bloom in coastal waters of the Gulf of Alaska.

  2. Alaska: Glaciers of Kenai Fjords National Park and Katmai National Park and Preserve (Chapter 12)

    NASA Technical Reports Server (NTRS)

    Giffen, Bruce A.; Hall, Dorothy K.; Chien, Janet Y.L.

    2007-01-01

    Much recent research points to the shrinkage of the Earth's small glaciers, however, few studies have been performed to quantify the amount of change over time. We measured glacier-extent changes in two national parks in southeastern Alaska. There are hundreds of glaciers in Kenai Fjords National Park (KEFJ) and Katmai National Park and Preserve (KATM) covering over 2373 sq km of parkland. There are two primary areas of glaciation in KEFJ - the Harding Icefield and the Grewingk-Yalik Glacier Complex, and three primary areas of glaciation in KATM - the Mt. Douglas area, the Kukak Volcano to Mt. Katmai area and the Mt. Martin area. We performed glacier mapping using satellite imagery, from the 1970s, 1980s, and from 2000. Results of the analysis show that there has been a reduction in the amount of glacier ice cover in the two parks over the study period, of approximately 22 sq km of ice, approximately - 1.6% from 1986 to 2000 (for KEFJ), and of approximately 76 sq km of glacier ice, or about -7.7% from 1986187 to 2000 (for KATM). In the future, measurements of surface elevation changes of these ice masses should be acquired; together with our extent-change measurements, the volume change of the ice masses can then be determined to estimate their contribution to sea-level rise. The work is a continuation of work done in KEFJ, but in KATM, our measurements represent the first comprehensive study of the glaciers in this remote, little-studied area.

  3. Alaska: Glaciers of Kenai Fjords National Park and Katmai National Park and Preserve

    NASA Technical Reports Server (NTRS)

    Giffens, Bruce A.; Hall, Dorothy K.; Chien, Janet Y. L.

    2014-01-01

    There are hundreds of glaciers in Kenai Fjords National Park (KEFJ) and Katmai National Park and Preserve (KATM) covering over 2,276 sq km of park land (ca. 2000). There are two primary glacierized areas in KEFJ (the Harding Icefield and the Grewingk-Yalik Glacier Complex) and three primary glacierized areas in KATM (the Mt. Douglas area, the Kukak Volcano to Mt. Katmai area, and the Mt. Martin area). Most glaciers in these parks terminate on land, though a few terminate in lakes. Only KEFJ has tidewater glaciers, which terminate in the ocean. Glacier mapping and analysis of the change in glacier extent has been accomplished on a decadal scale using satellite imagery, primarily Landsat data from the 1970s, 1980s, and from2000. Landsat Multispectral Scanner (MSS),Thematic Mapper (TM), and Enhanced Thematic Mapper Plus (ETM) imagery was used to map glacier extent on a park-wide basis. Classification of glacier ice using image-processing software, along with extensive manual editing, was employed to create Geographic Information System (GIS)outlines of the glacier extent for each park. Many glaciers that originate in KEFJ but terminate outside the park boundaries were also mapped. Results of the analysis show that there has been a reduction in the amount of glacier ice cover in the two parks over the study period. Our measurements show a reduction of approximately 21 sq km, or 1.5(from 1986 to 2000), and 76 sq km, or 7.7 (from19861987 to 2000), in KEFJ and KATM, respectively. This work represents the first comprehensive study of glaciers of KATM. Issues that complicate the mapping of glacier extent include debris cover(moraine and volcanic ash), shadows, clouds, fresh snow, lingering snow from the previous season, and differences in spatial resolution between the MSS,TM, or ETM sensors. Similar glacier mapping efforts in western Canada estimate mapping errors of 34. Measurements were also collected from a suite of glaciers in KEFJ and KATM detailing terminus positions

  4. Alaska: Glaciers of Kenai Fjords National Park and Katmai and Lake Clark National Parks and Preserve

    NASA Technical Reports Server (NTRS)

    Giffen, bruce A.; Hall, Dorothy K.; Chien, Janet Y. L.

    2011-01-01

    There are hundreds of glaciers in Kenai Fjords National Park (KEFJ) and Katmai National Park and Preserve (KATM) covering over 2276 sq km of park land (circa 2000). There are two primary glacierized areas in KEFJ -- the Harding Icefield and the Grewingk-Yalik Glacier Complex, and three primary glacierized areas in KATM - the Mt. Douglas area, the Kukak Volcano to Mt. Katmai area and the Mt. Martin area. Most glaciers in these parks terminate on land, though a few terminate in lakes. Only KEFJ has tidewater glaciers, which terminate in the ocean. Glacier mapping and analysis of the change in glacier extent has been accomplished on a decadal scale using satellite imagery, primarily Landsat data from the 1970s, 1980s, and from 2000. Landsat Multispectral Scanner (MSS), Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) imagery was used to map glacier extent on a park-wide basis. Classification of glacier ice using image processing software, along with extensive manual editing, was employed to create Geographic Information System (GIS) outlines of the glacier extent for each park. Many glaciers that originate in KEFJ but terminate outside the park boundaries were also mapped. Results of the analysis show that there has been a reduction in the amount of glacier ice cover in the two parks over the study period. Our measurements show a reduction of approximately 21 sq km, or -1.5% (from 1986 to 2000), and 76 sq km, or -7.7% (from 1986/87 to 2000), in KEFJ and KATM, respectively. This work represents the first comprehensive study of glaciers of KATM. Issues that complicate the mapping of glacier extent include: debris-cover (moraine and volcanic ash), shadows, clouds, fresh snow, lingering snow from the previous season, and differences in spatial resolution between the MSS and TM or ETM+ sensors. Similar glacier mapping efforts in western Canada estimate mapping errors of 3-4%. Measurements were also collected from a suite of glaciers in KEFJ and KATM detailing

  5. Kittlitz's and Marbled Murrelets in Kenai Fjords National Park, South-Central Alaska: At-Sea Distribution, Abundance, and Foraging Habitat, 2006-08

    USGS Publications Warehouse

    Arimitsu, M.L.; Piatt, J.F.; Romano, Marc D.; Madison, E.N.; Conaway, J.S.

    2010-01-01

    Kittlitz's murrelets (Brachyramphus brevirostris) and marbled murrelets (B. marmoratus) are small diving seabirds and are of management concern because of population declines in coastal Alaska. In 2006-08, we conducted a study in Kenai Fjords National Park, south-central Alaska, to estimate the recent population size of Brachyramphus murrelets, to evaluate productivity based on juvenile to adult ratios during the fledgling season, and to describe and compare their use of marine habitat. We also attempted a telemetry study to examine Kittlitz's murrelet nesting habitat requirements and at-sea movements. We estimated that the Kittlitz's murrelet population was 671 ? 144 birds, and the marbled murrelet population was 5,855 ? 1,163 birds. Kittlitz's murrelets were limited to the heads of three fjords with tidewater glaciers, whereas marbled murrelets were more widely distributed. Population estimates for both species were lower in 2007 than in 2006 and 2008, possibly because of anomalous oceanographic conditions that may have delayed breeding phenology. During late season surveys, we observed few hatch-year marbled murrelets and only a single hatch-year Kittlitz's murrelet over the course of the study. Using radio telemetry, we found a likely Kittlitz's murrelet breeding site on a mountainside bordering one of the fjords. We never observed radio-tagged Kittlitz's murrelets greater than 10 kilometer from their capture sites, suggesting that their foraging range during breeding is narrow. We observed differences in oceanography between fjords, reflecting differences in sill characteristics and orientation relative to oceanic influence. Acoustic biomass, a proxy for zooplankton and small schooling fish, generally decreased with distance from glaciers in Northwestern Lagoon, but was more variable in Aialik Bay where dense forage fish schools moved into glacial areas late in the summer. Pacific herring (Clupea pallasii), capelin (Mallotus villosus) and Pacific sand lance

  6. Glacier fluctuations in the Kenai Fjords, Alaska, U.S.A.: An evaluation of controls on Iceberg-calving glaciers

    SciTech Connect

    Wiles, G.C.; Calkin, P.E.; Post, A.

    1995-08-01

    The histories of four iceberg-calving outlet-glacier systems in the Kenai Fjords National Park underscore the importance of fiord depth, sediment supply, and fiord geometry on glacier stability. These parameters, in turn, limit the reliability of calving glacier chronologies as records of climatic change. Tree-ring analysis together with radiocarbon dating show that the Northwestern and McCarty glaciers, with large drainage basins, were advancing in concert with nearby land-terminating glaciers about A.D. 600. After an interval of retreat and possible nonclimatically induced extension during the Medieval Warm Period, these ice margins advanced again through the Little Ice Age and then retreated synchronously with the surrounding land-terminating glaciers about A.D. 1900. In contrast, Holgate and Aialik glaciers, with deeper fiords and smaller basins, retreated about 300 yr earlier. Reconstructions of Little Ice Age glaciers suggest that equilibrium-line altitudes of Northwestern and McCarty glaciers were, respectively, 270 and 500 m lower than now. Furthermore, the reconstructions show that these two glaciers were climatically sensitive when at their terminal moranies. However, with ice margins at their present recessional positions and accumulation area ratios between 0.8 and 0.9, only McCarty Glacier shows evidence of advance. Aialik and Holgate glaciers were climatically insensitive during the Little Ice Age maxima and remain insensitive to climate. 40 refs., 7 figs., 2 tabs.

  7. Summer inventory of landbirds in Kenai Fjords National Park

    USGS Publications Warehouse

    2006-01-01

    As part of the National Park Service Inventory and Monitoring Program, we conducted a summer inventory of landbirds within Kenai Fjords National Park. Using a stratified random sampling design of areas accessible by boat or on foot, we selected sites that encompassed the breadth of habitat types within the Park. We detected 101 species across 52 transects, including 62 species of landbirds, which confirmed presence of 87% of landbird species expected to occur in the Park during the summer breeding season. We found evidence of breeding for three Partners in Flight Watch List species, Rufous Hummingbird (Selasphorus rufus), Olive-sided Flycatcher (Contopus cooperi), and Rusty Blackbird (Euphagus carolinus), which are of particular conservation concern due to recent population declines. Kenai Fjords National Park supports extremely high densities of Hermit Thrush, Orange-crowned Warbler, and Wilson’s Warbler (Wilsonia pusilla) compared with other regions of Alaska. Other commonly observed species included Fox Sparrow (Passerella iliaca), Varied Thrush (Ixoreus naevius), Rubycrowned Kinglet (Regulus calendula), and Yellow Warbler (Dendroica petechia). More than half of the landbird species we observed occurred in needleleaf forests, and several of these species were strongly associated with the coastforest interface. Tall shrub habitats, which occurred across all elevations and in recently deglaciated areas, supported high densities and a diverse array of passerines. Two major riparian corridors, with their broadleaf forests, wetlands, and connectivity to interior Alaska, provided unique and important landbird habitats within the region.

  8. Permian Tethyan Fusulinina from the Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Stevens, C.H.; Davydov, V.I.; Bradley, D.

    1997-01-01

    Two samples from a large, allochthonous limestone block in the McHugh Complex of the Chugach terrane on the Kenai Peninsula, Alaska, contain species of 12 genera of Permian Fusulinina including Abadehella, Kahlerina, Pseudokahlerina?, Nankinella, Codonofusiella, Dunbarula, Parafusulina?, Chusenella, Verbeekina, Pseudodoliolina, Metadoliolina?, Sumatrina?, and Yabeina, as well as several other foraminiferans and one alga. The assemblage of fusulinids is characteristically Tethyan, belonging to the Yabeina archaica zone of early Midian (late Wordian) age. Similar faunas are known from the Pamirs, Transcaucasia, and Japan, as well as from allochthonous terranes in British Columbia, northwestern Washington, and Koryakia in eastern Siberia.

  9. Hydraulic characteristics near streamside structures along the Kenai River, Alaska

    USGS Publications Warehouse

    Dorava, Joseph M.

    1995-01-01

    Hydraulic characteristics, water velocity, depth, and flow direction were measured near eight sites along the Kenai River in southcentral Alaska. Each of the eight sites contained a different type of structure: a road-type boat launch, a canal-type boat launch, a floating dock, a rock retaining wall, a pile-supported dock, a jetty, a concrete retaining wall, and a bank stabilization project near the city of Soldotna. Measurements of hydraulic characteristics were made to determine to what extent the structures affected natural or ambient stream hydraulic characteristics. The results will be used by the Alaska Department of Fish and Game to evaluate assumptions used in their Habitat Evaluation Procedure assessment of juvenile chinook salmon habitat along the river and to improve their understanding of stream hydraulics for use in permitting potential projects. The study included structures along the Kenai River from about 12 to 42 miles upstream from the mouth. Hydraulic characteristics were measured during medium-, high-, and low-flow conditions, as measured at the Kenai River at Soldotna: (1) discharge ranged from 6,310 to 6,480 cubic feet per second during medium flow conditions that were near mean annual flow on June 9-10, 1994; (2) discharge ranged from 14,000 to 14,400 cubic feet per second during high flow conditions that were near peak annual flow conditions on August 2-3, 1994; and (3) discharge ranged from 3,470 to 3,660 cubic feet per second during open-water low-flow conditions on May 8-9, 1995. Measurements made at the structures were compared with measurements made at nearby unaffected natural sites. The floating dock, pile-supported dock, road-type boat launch, and concrete retaining wall did not significantly alter the stream channel area. These structures contributed only hydraulic-roughness type changes. The structures occupied a much smaller area than that of the wetted perimeter of the channel and thus typically had little effect on velocity

  10. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Fjords and Admiralty Island National Monuments, Alaska. 228.80 Section 228.80 Parks, Forests, and Public... Operations within Misty Fjords and Admiralty Island National Monuments, Alaska. (a) Mineral activities on valid mining claims in the Misty Fjords and Admiralty Island National Monuments must be conducted...

  11. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Fjords and Admiralty Island National Monuments, Alaska. 228.80 Section 228.80 Parks, Forests, and Public... Operations within Misty Fjords and Admiralty Island National Monuments, Alaska. (a) Mineral activities on valid mining claims in the Misty Fjords and Admiralty Island National Monuments must be conducted...

  12. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Fjords and Admiralty Island National Monuments, Alaska. 228.80 Section 228.80 Parks, Forests, and Public... Operations within Misty Fjords and Admiralty Island National Monuments, Alaska. (a) Mineral activities on valid mining claims in the Misty Fjords and Admiralty Island National Monuments must be conducted...

  13. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Fjords and Admiralty Island National Monuments, Alaska. 228.80 Section 228.80 Parks, Forests, and Public... Operations within Misty Fjords and Admiralty Island National Monuments, Alaska. (a) Mineral activities on valid mining claims in the Misty Fjords and Admiralty Island National Monuments must be conducted...

  14. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Fjords and Admiralty Island National Monuments, Alaska. 228.80 Section 228.80 Parks, Forests, and Public... Operations within Misty Fjords and Admiralty Island National Monuments, Alaska. (a) Mineral activities on valid mining claims in the Misty Fjords and Admiralty Island National Monuments must be conducted...

  15. Genetic characterization of Kenai brown bears (Ursus arctos): Microsatellite and mitochondrial DNA control region variation in brown bears of the Kenai Peninsula, south central Alaska

    USGS Publications Warehouse

    Jackson, J.V.; Talbot, S.L.; Farley, S.

    2008-01-01

    We collected data from 20 biparentally inherited microsatellite loci, and nucleotide sequence from the maternally inherited mitochondrial DNA (mtDNA) control region, to determine levels of genetic variation of the brown bears (Ursus arctos L., 1758) of the Kenai Peninsula, south central Alaska. Nuclear genetic variation was similar to that observed in other Alaskan peninsular populations. We detected no significant inbreeding and found no evidence of population substructuring on the Kenai Peninsula. We observed a genetic signature of a bottleneck under the infinite alleles model (IAM), but not under the stepwise mutation model (SMM) or the two-phase model (TPM) of microsatellite mutation. Kenai brown bears have lower levels of mtDNA haplotypic diversity relative to most other brown bear populations in Alaska. ?? 2008 NRC.

  16. Tephra layers as correlation tools of neogene coal-bearing strata from the Kenai lowland, Alaska

    SciTech Connect

    Reinink-Smith, L.M.

    1995-03-01

    Thirty-two tephra layers, exposed in coal beds of the Miocene and Pliocene Beluga and Sterling Formations along the shores of the Kenai lowland on the northwestern Kenai Peninsula, Alaska, were studied in detail to improve the geochronology and regional correlation of the Sterling Formation and test prior correlations that were based on palynology and physical tracing of beds over short distances. Published radiogenic isotope data suggest an age span of approximately 4 m.y. for the Sterling Formation at this location but give discordant ages for individual samples depending on dating techniques. A crystal-rich tephra layer near the middle of the section was traced across the Kenai lowland as one or two ash falls based on stratigraphic position, inertinite contents of adjacent coal, geochemical and mineralogical analyses, and individual characteristics. A pumice-rich layer deposited near the top of the Sterling Formation is preserved at two localities on the northwestern and southeastern sides of the Kenai lowland. Geochemical similarities, similar glass morphologies, and an absence of opaque phases characterize this layer as a single ash fall and allow correlation. On a regional scale, these correlations concur with previous correlations and show that a shallow anticline with a northwest-southeast-trending axis extends across the Kenai lowland. 28 refs., 14 figs., 1 tab.

  17. Salmon Futures: Stakeholder-driven salmon management scenarios under changing environmental conditions on Alaska's Kenai Peninsula

    NASA Astrophysics Data System (ADS)

    Trammell, E. J.; Krupa, M.

    2015-12-01

    Understanding the adaptive capacity of individuals within natural resource management agencies is a key component of assessing the vulnerability of salmon to future environmental change. We seek to explore the adaptive capacity of natural resource agencies on Alaska's Kenai Peninsula by exploring the drivers and implications of different salmon allocation scenarios through participatory workshops with managers. We present here the initial results from the first workshop, which explores the various drivers responsible for changes in salmon allocation. Ranging from global to local, and biophysical to socioeconomic, these drivers are also linked to specific actors in the region. These complex interactions comprise the Kenai Peninsula's social-ecological system and determine its ability to react to change. Using a stakeholder-driven scenario framework, we aim to: 1) explore the adaptive capacity of natural resource agencies in the region by exploring and exposing managers to different but logically coherent salmon allocation scenarios; 2) build stakeholder confidence in the science of environmental change on the Kenai Peninsula; and 3) develop a decision support tool that helps regional resource managers better understand their changing environment. We utilize and present the scenario framework as a platform for integrating hydrologic, landscape, and cultural change information into actionable decisions, crafted by the stakeholders, so that landscape change on the Kenai becomes more coordinated.

  18. Sea otter abundance in Kenai Fjords national Park: results from the 2010 aerial survey

    USGS Publications Warehouse

    Coletti, Heather A.; Bodkin, James L.; Esslinger, George

    2011-01-01

    Fjord, Nuka Bay and Nuka Island. All observed otters were in the high density stratum, defined as the 0 m to 40 m depth contour and minimum distances from shore, while no sea otters were observed in the low density stratum, which is defined as the area within the 40m to 100 m depth contour. We recommend that prior to the next aerial sea otter survey in KEFJ (scheduled for 2013), a power simulation be conducted to evaluate methods to improve precision of estimates and the ability to detect change.

  19. Geology of the Prince William Sound and Kenai Peninsula region, Alaska

    USGS Publications Warehouse

    Wilson, Frederic H.; Hults, Chad P.

    2012-01-01

    The Prince William Sound and Kenai Peninsula region includes a significant part of one of the world’s largest accretionary complexes and a small part of the classic magmatic arc geology of the Alaska Peninsula. Physiographically, the map area ranges from the high glaciated mountains of the Alaska and Aleutian Ranges and the Chugach Mountains to the coastal lowlands of Cook Inlet and the Copper River delta. Structurally, the map area is cut by a number of major faults and postulated faults, the most important of which are the Border Ranges, Contact, and Bruin Bay Fault systems. The rocks of the map area belong to the Southern Margin composite terrane, a Tertiary and Cretaceous or older subduction-related accretionary complex, and the Alaska Peninsula terrane. Mesozoic rocks between these two terranes have been variously assigned to the Peninsular or the Hidden terranes. The oldest rocks in the map area are blocks of Paleozoic age within the mélange of the McHugh Complex; however, the protolith age of the greenschist and blueschist within the Border Ranges Fault zone is not known. Extensive glacial deposits mantle the Kenai Peninsula and the lowlands on the west side of Cook Inlet and are locally found elsewhere in the map area. This map was compiled from existing mapping, without generalization, and new or revised data was added where available.

  20. Glacial runoff strongly influences food webs in Gulf of Alaska fjords

    NASA Astrophysics Data System (ADS)

    Arimitsu, M.; Piatt, J. F.; Mueter, F. J.

    2015-12-01

    Melting glaciers contribute large volumes of freshwater to the Gulf of Alaska coast. Rates of glacier volume loss have increased markedly in recent decades, raising concern about the eventual loss of glaciers as a source of freshwater in coastal waters. To better understand the influence of glacier melt water on fjord ecosystems, we sampled oceanography, nutrients, zooplankton, forage fish, and seabirds within four fjords in the coastal Gulf of Alaska. We used generalized additive models and geostatistics to identify the range of influence of glacier runoff in fjords of varying estuarine and topographic complexity. We also modeled the responses of chlorophyll a concentration, copepod biomass, fish and seabird abundance to physical, nutrient and biotic predictor variables. Physical and nutrient signatures of glacial runoff extended 10-20 km into coastal fjords. Glacially modified physical gradients and among-fjord differences explained 66% of the variation in phytoplankton abundance, which drives ecosystem structure at higher trophic levels. Copepod, euphausiid, fish and seabird distribution and abundance were also related to environmental gradients that could be traced to glacial freshwater input. Seabird density was predicted by prey availability and silica concentrations, which may indicate upwelling areas where this nutrient is in excess. Similarities in ecosystem structure among fjords were due to influx of cold, fresh, sediment and nutrient laden water, while differences were due to fjord topography and the relative importance of estuarine vs. ocean influences. We anticipate continued changes in the volume and magnitude of glacial runoff will affect coastal marine food webs in the future.

  1. Magnetic Properties of Quaternary Deposits, Kenai Peninsula, Alaska -- Implications for Aeromagnetic Anomalies of Upper Cook Inlet

    USGS Publications Warehouse

    Saltus, R.W.; Haeussler, P.J.

    2004-01-01

    We measured magnetic susceptibilities of exposed Quaternary deposits on several beach cliffs and river banks on the Kenai Peninsula near Soldotna, Alaska. Data, descriptions, and photos from nine sites are included in this report. The mean susceptibility for Quaternary materials in this region is approximately 2.5 x 10-3 SI units. This is sufficiently magnetic to produce subtle aeromagnetic anomalies such as those observed to correlate with topographic features in the region of the measurements. The highest susceptibilities measured (greater than 20 x 10-3 SI units) may help, at least in part, to explain moderate amplitude aeromagnetic anomalies observed elsewhere in Cook Inlet, particularly those relating to structures showing Quaternary movement. Comparison of measured beach cliff susceptibility and susceptibility predicted from idealized formulas and two-dimensional cliff models suggests that measured susceptibilies underestimate true bulk susceptibility by 20 percent to 50 percent in this region.

  2. Rock uplift at the transition from flat-slab to normal subduction: The Kenai Mountains, Southeast Alaska

    NASA Astrophysics Data System (ADS)

    Valentino, Joshua D.; Spotila, James A.; Owen, Lewis A.; Buscher, Jamie T.

    2016-03-01

    The process of flat-slab subduction results in complex deformation of overlying forearcs, yet how this deformation decays with distance away from the zone of underthrusting is not well understood. In south central Alaska, flat-slab subduction of the Yakutat microplate drives shortening and rock uplift in a broad coastal orogenic belt. Defined limits of the zone of underthrusting allow testing how orogenesis responds to the transition from flat-slab to normal subduction. To better understand forearc deformation across this transition, apatite (U-Th)/He low temperature thermochronometry is used to quantify the exhumation history of the Kenai Mountains that are within this transition zone. Measured ages in the northern Kenai Mountains vary from 10-20 Ma and merge with the exhumation pattern in the Chugach Mountains to the northeast, where high exhumation occurs due to flat-slab-related deformation. In the southern Kenai Mountains, however, ages increase to 30-50 Ma across a transition near Seward, Alaska, above the zone from flat-slab to normal subduction. These ages are relatively old in comparison to ages determined in other studies in southern Alaska and suggest minimal exhumation. Furthermore, transitions in topographic expression of the coastal orogen also occur at the margin of Yakutat underthrusting. These observations suggest that either deformation associated with flat-slab subduction requires tens of kilometers to decay with distance away from the zone of underthrusting, or that orogenesis in the Kenai Mountains is driven by a distinct tectonic cause. A potential driver of deformation is underplating of thick sediments, specifically the Surveyor Submarine Fan, along the Aleutian Megathrust, analogous to the tectonic mechanism responsible for the emergence of the Kodiak Island forearc. If correct, this may represent a recent tectonic transition in the region, given the minimal exhumation of the rugged Kenai Mountains despite the presence of an erosion

  3. Ground-water conditions and quality in the western part of Kenai Peninsula, southcentral Alaska

    USGS Publications Warehouse

    Glass, R.L.

    1996-01-01

    The western part of Kenai Peninsula in southcentral Alaska is bounded by Cook Inlet and the Kenai Mountains. Ground water is the predominant source of water for commercial, industrial, and domestic uses on the peninsula. Mean daily water use in an oil, gas, and chemical processing area north of Kenai is more than 3.5 million gallons. Unconsolidated sediments of glacial and fluvial origin are the most productive aquifers. In the upper (northwestern) peninsula, almost all water used is withdrawn from unconsolidated sediments, which may be as thick as 750 feet. In the lower peninsula, unconsolidated sediments are thinner and are absent on many hills. Water supplies in the lower peninsula are obtained from unconsolidated sediments and bedrock, and a public-water supply in parts of Homer is obtained from Bridge Creek. Throughout the peninsula, ground-water flow occurs primarily as localized flow controlled by permeability of aquifer materials and surface topography. The concentration of constituents analyzed in water from 312 wells indicated that the chemical quality of ground water for human consumption varies from marginal to excellent. Even though the median concentration of dissolved solids is low (152 milligrams per liter), much of the ground water on the peninsula does not meet water-quality regulations for public drinking water established by the U.S. Environmental Protection Agency (USEPA). About 8 percent of wells sampled yielded water having concentrations of dissolved arsenic that exceeded the USEPA primary maximum contaminant level of 50 micrograms per liter. Concentrations of dissolved arsenic were as great as 94 micrograms per liter. Forty-six percent of wells sampled yielded water having concentrations of dissolved iron greater than the USEPA secondary maximum contaminant level of 300 micrograms per liter. Unconsolidated sediments generally yield water having calcium, magnesium, and bicarbonate as its predominant ions. In some areas, ground water at

  4. Ground-water reconnaissance of part of the lower Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Nelson, G.L.; Johnson, P.R.

    1981-01-01

    Most residential and industrial development of the Lower Kenai Peninsula, Alaska, is along the coast of Cook Inlet. Most of the information about subsurface conditions is obtained from wells along the coast. Ground water is recharged by local precipitation, and slow drainage of ground water to the streams maintains streamflow during winters and periods of no precipitation. Sedimentary bedrock of the Tertiary Kenai Group is the principal source of water to wells, but subsurface data are too sparse to differentiate individual aquifers within the bedrock. Most bedrock wells are completed in poorly consolidated sandstone. Glacial till overlies bedrock in much of the study area, but few wells obtain water from the poorly permeable till. Glacial outwash and abandoned-channel deposits in major drainageways of alluvial plains provide water to wells but are little utilized and have not been explored by drilling. Intermorainal valleys and areas of low relief are poorly drained , and bog deposits overlie surficial materials in parts of the area. Bog deposits contain highly colored, iron-rich water that is undesirable to most consumers. Lacustrine clays overlie and are interbedded with fluvial materials and contain little extractable water. Streams have incised older glacial sediments and deposited alluvium along the present flood plains. Where the alluvium is thick enough, it has good potential for providing ground water to high-capacity wells. However, production of ground water from alluvium or other deposits hydraulically connected to streams will reduce streamflow. Surficial deposits with the best potential for developing significant ground-water supplies in the study area are the deltaic complex near the mouth of Kasilof River, the alluvium of Crooked Creek, and abandoned-channel deposits in the alluvial plain near Ninilchik and in an ancestral drainageway of Tustumena Glacier south of Crooked Creek. (USGS)

  5. Effectiveness of streambank-stabilization techniques along the Kenai River, Alaska

    USGS Publications Warehouse

    Dorava, Joseph M.

    1999-01-01

    The Kenai River in southcentral Alaska is the State's most popular sport fishery and an economically important salmon river that generates as much as $70 million annually. Boatwake-induced streambank erosion and the associated damage to riparian and riverine habitat present a potential threat to this fishery. Bank-stabilization techniques commonly in use along the Kenai River were selected for evaluation of their effectiveness at attenuating boatwakes and retarding streambank erosion. Spruce trees cabled to the bank and biodegradable man-made logs (called 'bio-logs') pinned to the bank were tested because they are commonly used techniques along the river. These two techniques were compared for their ability to reduce wake heights that strike the bank and to reduce erosion of bank material, as well as for the amount and quality of habitat they provide for juvenile chinook salmon. Additionally, an engineered bank-stabilization project was evaluated because this method of bank protection is being encouraged by managers of the river. During a test that included 20 controlled boat passes, the spruce trees and the bio-log provided a similar reduction in boatwake height and bank erosion; however, the spruce trees provided a greater amount of protective habitat than the bio-log. The engineered bank-stabilization project eroded less during nine boat passes and provided more protective cover than the adjacent unprotected natural bank. Features of the bank-stabilization techniques, such as tree limbs and willow plantings that extended into the water from the bank, attenuated the boatwakes, which helped reduce erosion. These features also provided protective cover to juvenile salmon.

  6. Holocene glacier fluctuations inferred from lacustrine sediment, Emerald Lake, Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    LaBrecque, Taylor S.; Kaufman, Darrell S.

    2016-01-01

    Physical and biological characteristics of lacustrine sediment from Emerald Lake were used to reconstruct the Holocene glacier history of Grewingk Glacier, southern Alaska. Emerald Lake is an ice-marginal threshold lake, receiving glaciofluvial sediment when Grewingk Glacier overtops the topographic divide that separates it from the lake. Sub-bottom acoustical profiles were used to locate core sites to maximize both the length and resolution of the sedimentary sequence recovered in the 4-m-long cores. The age model for the composite sequence is based on 13 14C ages and a 210Pb profile. A sharp transition from the basal inorganic mud to organic-rich mud at 11.4 ± 0.2 ka marks the initial retreat of Grewingk Glacier below the divide of Emerald Lake. The overlaying organic-rich mud is interrupted by stony mud that records a re-advance between 10.7 ± 0.2 and 9.8 ± 0.2 ka. The glacier did not spill meltwater into the lake again until the Little Ice Age, consistent with previously documented Little Ice Ages advances on the Kenai Peninsula. The retreat of Grewingk Glacier at 11.4 ka took place as temperature increased following the Younger Dryas, and the subsequent re-advance corresponds with a climate reversal beginning around 11 ka across southern Alaska.

  7. Assessing net community production in a glaciated Alaska fjord

    NASA Astrophysics Data System (ADS)

    Reisdorph, S. C.; Mathis, J. T.

    2014-09-01

    The impact of deglaciation in Glacier Bay (GLBA) has been observed to seasonally impact the biogeochemistry of this marine system. The influence from surrounding glaciers, particularly tidewater glaciers, has the potential to greatly impact the efficiency and structure of the marine food web within GLBA. To assess the magnitude, spatial and temporal variability of net community production (NCP) in a glaciated fjord, we measured dissolved inorganic carbon (DIC), inorganic macronutrients, dissolved oxygen (DO) and particulate organic carbon (POC) between July 2011 and July 2012 in Glacier Bay, AK. Seasonally-averaged data were analyzed on a regional basis to account for distinct biogeochemical differences within the Bay due to spatial variation in rates of primary production and the influence of glacial-fed stratification, particularly in the northern regions. High NCP rates were observed across the Bay (~ 54 to ~ 81 mmol C m-2 d-1) between the summer and fall of 2011. However, between the fall and winter, as well as between the winter and spring of 2012, air-sea fluxes of CO2 and organic matter respiration made NCP rates negative across most of the Bay as inorganic carbon and macronutrient concentrations returned to pre-bloom levels. The highest carbon production occurred within the lower bay between the summer and fall of 2011 with ~ 1.3 × 1010 g C season-1. Bay-wide, there was carbon production of ~ 2.6 × 1010 g C season-1 between the summer and fall. Respiration and air-sea gas exchange were the dominant drivers of carbon biogeochemistry between the fall and winter of 2012. The substantial spatial and temporal variability in our NCP estimates largely reflect glacial influences within the Bay, as melt-water is depleted in macronutrients relative to marine waters entering from the Gulf of Alaska in the middle and lower parts of the Bay. Further glacial retreat will likely lead to additional modifications in the carbon biogeochemistry of GLBA with unknown

  8. Uplift of the Kenai Peninsula, Alaska, since the 1964 Prince William Sound earthquake

    NASA Technical Reports Server (NTRS)

    Cohen, Steven; Holdahl, Sandford; Caprette, Douglas; Hilla, Stephen; Safford, Robert; Schultz, Donald

    1995-01-01

    Using Global Positioning System (GPS) receivers, we reoccupied several leveling benchmarks on the Kenai Peninsula of Alaska which had been surveyed by conventional leveling immediately following the March 27, 1964, Prince William Sound earthquake (M(sub w) = 9.3). By combining the two sets of measurements with a new, high-resolution model of the geoid in the region, we were able to determine the cumulative 1993-1964 postseismic vertical displacement. We find uplift at all of our benchmarks, relative to Seward, Alaska, a point that is stable according to tide gauge data. The maximum uplift of about 1 m occurs near the middle of the peninsula. The region of maximum uplift appears to be shifted northwest relative to the point of maximum coseismic subsidence. If we use tide gauge data at Nikishka and Seward to constrain the vertical motion, then the observed uplift has a trenchward tilt (down to the southeast) as well as an arching component. To explain the observations, we use creep-at-depth models. Most acceptable models require a fault slip of about 2.75 m, although this result is not unique. If the slip has been continuous since the 1964 earthquake, then the average slip rate is nearly 100 mm/yr, twice the plate convergence rate. Comparing the net uplift achieved in 29 years with that observed over 11 years in an adjacent region southeast of Anchorage, Alaska, we conclude that the rate of uplift is decreasing. A further decrease in the uplift rate is expected as the 29-year averaged displacement rate is about twice the plate convergence rate and therefore cannot be sustained over the entire earthquake cycle.

  9. Late Quaternary distal tephra-fall deposits in lacustrine sediments, Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    de Fontaine, Christian S.; Kaufman, Darrell S.; Scott Anderson, R.; Werner, Al; Waythomas, Christopher F.; Brown, Thomas A.

    2007-07-01

    Tephra-fall deposits from Cook Inlet volcanoes were detected in sediment cores from Tustumena and Paradox Lakes, Kenai Peninsula, Alaska, using magnetic susceptibility and petrography. The ages of tephra layers were estimated using 21 14C ages on macrofossils. Tephras layers are typically fine, gray ash, 1-5 mm thick, and composed of varying proportions of glass shards, pumice, and glass-coated phenocrysts. Of the two lakes, Paradox Lake contained a higher frequency of tephra (0.8 tephra/100 yr; 109 over the 13,200-yr record). The unusually large number of tephra in this lake relative to others previously studied in the area is attributed to the lake's physiography, sedimentology, and limnology. The frequency of ash fall was not constant through the Holocene. In Paradox Lake, tephra layers are absent between ca. 800-2200, 3800-4800, and 9000-10,300 cal yr BP, despite continuously layered lacustrine sediment. In contrast, between 5000 and 9000 cal yr BP, an average of 1.7 tephra layers are present per 100 yr. The peak period of tephra fall (7000-9000 cal yr BP; 2.6 tephra/100 yr) in Paradox Lake is consistent with the increase in volcanism between 7000 and 9000 yr ago recorded in the Greenland ice cores.

  10. Perceptions of wildfire and landscape change in the Kenai Peninsula, Alaska.

    PubMed

    Gordon, Jason S; Gruver, Joshua B; Flint, Courtney G; Luloff, A E

    2013-10-01

    Despite a broad literature addressing the human dimensions of wildfire, current approaches often compartmentalize results according to disciplinary boundaries. Further, relatively few studies have focused on the public's evolving perceptions of wildfire as communities change over time. This paper responds to these gaps by exploring perceptions of landscape dynamics and wildfire between 2003 and 2007 using a typological framework of intersecting ecological, social, and cultural processes. Designed as a restudy, and using key informant interviews, this research allowed us to observe risk perception as they are related to community challenges and opportunities in the Kenai Peninsula, Alaska. Risk perceptions were examined as an integral part of community and landscape change. Wildfire was a concern among informants in 2003 and remained a concern in 2007, although informants were less likely to discuss it as a major threat compared to the original study. Informants in the western part of the peninsula tended to express more concern about wildfire than their eastern counterparts largely due to their experiences with recent fires. Other important factors residents considered included changing forest fuels, the expanding wildland urban interface, and contrasting values of new residents. Underscoring the localized nature of risk perceptions, informants had difficulty describing the probability of a wildfire event in a geographical context broader than the community scale. This paper demonstrates how a holistic approach can help wildfire and natural resource professionals, community members, and other stakeholders understand the social and physical complexities influencing collective actions or inactions to address the threat of wildfire.

  11. Landsat-faciliated vegetation classification of the Kenai National Wildlife Refuge and adjacent areas, Alaska

    USGS Publications Warehouse

    Talbot, S. S.; Shasby, M.B.; Bailey, T.N.

    1985-01-01

    A Landsat-based vegetation map was prepared for Kenai National Wildlife Refuge and adjacent lands, 2 million and 2.5 million acres respectively. The refuge lies within the middle boreal sub zone of south central Alaska. Seven major classes and sixteen subclasses were recognized: forest (closed needleleaf, needleleaf woodland, mixed); deciduous scrub (lowland and montane, subalpine); dwarf scrub (dwarf shrub tundra, lichen tundra, dwarf shrub and lichen tundra, dwarf shrub peatland, string bog/wetlands); herbaceous (graminoid meadows and marshes); scarcely vegetated areas ; water (clear, moderately turbid, highly turbid); and glaciers. The methodology employed a cluster-block technique. Sample areas were described based on a combination of helicopter-ground survey, aerial photo interpretation, and digital Landsat data. Major steps in the Landsat analysis involved: preprocessing (geometric connection), spectral class labeling of sample areas, derivation of statistical parameters for spectral classes, preliminary classification of the entree study area using a maximum-likelihood algorithm, and final classification through ancillary information such as digital elevation data. The vegetation map (scale 1:250,000) was a pioneering effort since there were no intermediate-sclae maps of the area. Representative of distinctive regional patterns, the map was suitable for use in comprehensive conservation planning and wildlife management.

  12. Late Quaternary distal tephra-fall deposits in lacustrine sediments, Kenai Peninsula, Alaska

    USGS Publications Warehouse

    de Fontaine, C.S.; Kaufman, D.S.; Scott, Anderson R.; Werner, A.; Waythomas, C.F.; Brown, T.A.

    2007-01-01

    Tephra-fall deposits from Cook Inlet volcanoes were detected in sediment cores from Tustumena and Paradox Lakes, Kenai Peninsula, Alaska, using magnetic susceptibility and petrography. The ages of tephra layers were estimated using 21 14C ages on macrofossils. Tephras layers are typically fine, gray ash, 1-5??mm thick, and composed of varying proportions of glass shards, pumice, and glass-coated phenocrysts. Of the two lakes, Paradox Lake contained a higher frequency of tephra (0.8 tephra/100 yr; 109 over the 13,200-yr record). The unusually large number of tephra in this lake relative to others previously studied in the area is attributed to the lake's physiography, sedimentology, and limnology. The frequency of ash fall was not constant through the Holocene. In Paradox Lake, tephra layers are absent between ca. 800-2200, 3800-4800, and 9000-10,300??cal yr BP, despite continuously layered lacustrine sediment. In contrast, between 5000 and 9000??cal yr BP, an average of 1.7 tephra layers are present per 100 yr. The peak period of tephra fall (7000-9000??cal yr BP; 2.6 tephra/100 yr) in Paradox Lake is consistent with the increase in volcanism between 7000 and 9000 yr ago recorded in the Greenland ice cores. ?? 2007 Elsevier Inc. All rights reserved.

  13. Perceptions of wildfire and landscape change in the Kenai Peninsula, Alaska.

    PubMed

    Gordon, Jason S; Gruver, Joshua B; Flint, Courtney G; Luloff, A E

    2013-10-01

    Despite a broad literature addressing the human dimensions of wildfire, current approaches often compartmentalize results according to disciplinary boundaries. Further, relatively few studies have focused on the public's evolving perceptions of wildfire as communities change over time. This paper responds to these gaps by exploring perceptions of landscape dynamics and wildfire between 2003 and 2007 using a typological framework of intersecting ecological, social, and cultural processes. Designed as a restudy, and using key informant interviews, this research allowed us to observe risk perception as they are related to community challenges and opportunities in the Kenai Peninsula, Alaska. Risk perceptions were examined as an integral part of community and landscape change. Wildfire was a concern among informants in 2003 and remained a concern in 2007, although informants were less likely to discuss it as a major threat compared to the original study. Informants in the western part of the peninsula tended to express more concern about wildfire than their eastern counterparts largely due to their experiences with recent fires. Other important factors residents considered included changing forest fuels, the expanding wildland urban interface, and contrasting values of new residents. Underscoring the localized nature of risk perceptions, informants had difficulty describing the probability of a wildfire event in a geographical context broader than the community scale. This paper demonstrates how a holistic approach can help wildfire and natural resource professionals, community members, and other stakeholders understand the social and physical complexities influencing collective actions or inactions to address the threat of wildfire. PMID:23884356

  14. Perceptions of Wildfire and Landscape Change in the Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Gordon, Jason S.; Gruver, Joshua B.; Flint, Courtney G.; Luloff, A. E.

    2013-10-01

    Despite a broad literature addressing the human dimensions of wildfire, current approaches often compartmentalize results according to disciplinary boundaries. Further, relatively few studies have focused on the public's evolving perceptions of wildfire as communities change over time. This paper responds to these gaps by exploring perceptions of landscape dynamics and wildfire between 2003 and 2007 using a typological framework of intersecting ecological, social, and cultural processes. Designed as a restudy, and using key informant interviews, this research allowed us to observe risk perception as they are related to community challenges and opportunities in the Kenai Peninsula, Alaska. Risk perceptions were examined as an integral part of community and landscape change. Wildfire was a concern among informants in 2003 and remained a concern in 2007, although informants were less likely to discuss it as a major threat compared to the original study. Informants in the western part of the peninsula tended to express more concern about wildfire than their eastern counterparts largely due to their experiences with recent fires. Other important factors residents considered included changing forest fuels, the expanding wildland urban interface, and contrasting values of new residents. Underscoring the localized nature of risk perceptions, informants had difficulty describing the probability of a wildfire event in a geographical context broader than the community scale. This paper demonstrates how a holistic approach can help wildfire and natural resource professionals, community members, and other stakeholders understand the social and physical complexities influencing collective actions or inactions to address the threat of wildfire.

  15. Late Holocene climate change at Goat Lake, Kenai Mountains, south-central Alaska

    NASA Astrophysics Data System (ADS)

    Daigle, T. A.; Kaufman, D. S.

    2006-12-01

    Lake sediments, glacier extents, and tree rings were used to reconstruct late Holocene climate changes from Goat Lake in the Kenai Mountains, south-central Alaska (60° 14' N/149° 54' W). Two sediment cores (3.7 and 5.6 m long) were dated with 16 AMS 14C ages and record changes in watershed (organic- matter content) and within-lake (biogenic silica) productivity since ~9500 cal yr BP. Sediment analyses focused on the last 1000 yr; this interval includes a sharp transition from gyttja to inorganic mud at ~1660 AD, which marks the fist time since Pleistocene deglaciation that the north goat outlet glacier (NGO) of the Harding Icefield overtopped the drainage divide at 590 m asl to spill meltwater into Goat Lake. One 14C age of ~1535 AD from a subfossil log in the NGO valley requires ~125 yr for the NGO to thicken 150 m to the elevation of the drainage divide where it remained until ~1930. Since ~1930, the NGO has thinned 150 m and retreated 1.4 km. Equilibrium-line altitudes (ELA) were reconstructed for 12 cirque glaciers nearby Goat Lake based on the accumulation-area ratio (AAR) method following field mapping of ice-marginal features formed during the maximum Little Ice Age (LIA) in the 19th century. Maximum LIA ELA data (AAR = 0.58) were compared with 1950 ELA and yield an average lowering of 50 ± 20 m. Application of the local lapse rate of 0.47°C/100 m indicates an average ablation-season temperature reduction of 0.3°C during the maximum LIA compared to 1950, assuming no change in winter precipitation. A new tree-ring chronology from 27 hemlock trees in the Goat Lake watershed correlates with mean March through August temperature from Kenai airport (r = 0.35) and a 207 yr reconstruction indicates an average temperature reduction of 1.0°C from 1800-1900 compared with 1930-1950. Assuming no change in winter precipitation, then a 1°C cooling should have been associated with an ELA lowering by 200 m. This did not occur, and we suggest that some degree of

  16. Comparisons of spawning areas and times for two runs of chinook salmon (Oncorhynchus tshawytscha) in the Kenai River, Alaska

    USGS Publications Warehouse

    Burger, C.V.; Wilmot, R.L.; Wangaard, D.B.

    1985-01-01

    From 1979 to 1982,188 chinook salmon (Oncorhynchus tshawytscha) were tagged with radio transmitters to locate spawning areas in the glacial Kenai River, southcentral Alaska. Results confirmed that an early run entered the river in May and June and spawned in tributaries, and a late run entered the river from late June through August and spawned in the main stem. Spawning peaked during August in tributaries influenced by lakes, but during July in other tributaries. Lakes may have increased fall and winter temperatures of downstream waters, enabling successful reproduction for later spawning fish within these tributaries. This hypothesis assumes that hatching and emergence can be completed in a shorter time in lake-influenced waters. The time of upstream migration and spawning (mid- to late August) of the late run is unique among chinook stocks in Cook Inlet. This behavior may have developed only because two large lakes (Kenai and Skilak) directly influence the main-stem Kenai River. If run timing is genetically controlled, and if the various components of the two runs are isolated stocks that have adapted to predictable stream temperatures, there are implications for stock transplantation programs and for any activities of man that alter stream temperatures.

  17. Post-Flood Recovery of Invertebrate Communities on the Salmon Streams of the Lower Kenai Peninsula, Alaska.

    NASA Astrophysics Data System (ADS)

    Mauger, S.

    2005-05-01

    Cook Inlet Keeper and the Homer Soil and Water Conservation District have been partnering since 1998 to monitor water quality on the lower Kenai Peninsula's most economically, culturally, and socially important salmon streams: Anchor River, Stariski Creek, Deep Creek, and Ninilchik River. Although these rivers support abundant salmon populations and are nutrient rich, these waterways ranked only "fair" in a 1997 macroinvertebrate assessment of Kenai Peninsula salmon streams by the University of Alaska Anchorage's Environment and Natural Resources Institute, perhaps providing an early warning signal that these high priority watersheds are being degraded. These streams are under new stresses from: 1) population growth and urban sprawl; 2) widespread spruce bark beetle infestation; 3) elevated sediment and temperature levels; and 4) catastrophic flooding events in the Fall of 2002. Cook Inlet Keeper expanded its bioassessment program in 2003 and 2004 to track the biological communities in these streams and to understand flood effects on stream productivity. Preliminary results suggest that short term reductions in abundance but not diversity occurred after flood events and that chronic sediment deposition may be responsible for sub-optimal community assessments.

  18. A Synthesis of Characteristics of Submarine Landslides Generated by the 1964 Great Alaska Earthquake in Six Fjords

    NASA Astrophysics Data System (ADS)

    Haeussler, P. J.; Parsons, T.; Lee, H. J.; Ryan, H. F.; Brothers, D. S.; Liberty, L. M.; Hart, P. E.; Geist, E. L.; Roland, E. C.; Witter, R. C.; Kayen, R. E.

    2015-12-01

    Submarine landslide-generated tsunamis were the single largest cause of fatalities in the Mw9.2 1964 Great Alaska earthquake. In the last decade, we studied the submarine slope failures in six fjords: Resurrection Bay, Port Valdez, Passage Canal, southern Dangerous Passage, Aialik Bay, and Harris Bay. The six fjords lie 20 to 30 km above the Alaska-Aleutian megathrust, which provides an ideal landslide trigger mechanism. To characterize the landslides, we used multibeam bathymetry data, pre- and post-event bathymetry differencing, sparker and chirp seismic data, wave runup directions and heights, shear wave velocity profiles, the onland sedimentary record of the tsunamis, observations during the earthquake, and tsunami models. All slides originated at the margins of the fjords, mostly in unconsolidated sediment of the fjord-head deltas(?), and transported sediment to the deepest part of the fjords. The slides transported material up to ~15 km, resulting in slide deposits up to 20 m thick, and a subsequent megaturbidite deposit up to 15 m thick. These slides resurfaced the entire fjord bottom and the resultant flow of sediment and water brought numerous deep dwelling fish to the surface, killed by the sudden pressure changes. Typical fjord sedimentation resulted in conditions primed for slope failures. Fjord-head deltas deposited unconsolidated sediment at the upper margins of the fjords, which composed the majority of sediment that failed during the earthquake. We find that the highest tsunami runups were correlated with blocky landslides that required unique depositional conditions. The Little Ice Age (LIA) occurred between the penultimate megathrust earthquake ~900 yr ago and 1964, with the most recent maximum extent around 1875AD. The LIA glacial expansion led to significant sedimentation at the margins of the fjords. Near Shoup Bay in Port Valdez, in Passage Canal, and probably in southern Dangerous Passage, ice overrode till and sediment deposited in front of

  19. Neoglacial fluctuations of terrestrial, tidewater, and calving lacustrine glaciers, Blackstone-Spencer Ice Complex, Kenai Mountains, Alaska

    NASA Astrophysics Data System (ADS)

    Crossen, Kristine June

    1997-12-01

    The glaciers surrounding the Blackstone-Spencer Ice Complex display a variety of termini types: Tebenkov, Spencer, Bartlett, Skookum, Trail, Burns, Shakespeare, Marquette, Lawrence, and Ripon glaciers end in terrestrial margins; Blackstone and Beloit glaciers have tidewater termini; and Portage Glacier has a calving lacustrine margin. In addition, steep temperature and precipitation gradients exist across the ice complex from the maritime environment of Prince William Sound to the colder, drier interior. The Neoglacial history of Tebenkov Glacier, as based on overrun trees near the terminus, shows advances ca. 250- 430 AD (calibrated date), ca. 1215-1275 AD (calibrated date), and ca. 1320-1430 AD (tree ring evidence), all intervals of glacier advance around the Gulf of Alaska. However, two tidewater glaciers in Blackstone Bay retreated from their outermost moraines by 1350 AD, apparently asynchronously with respect to the regional climate signal. The most extensive Kenai Mountain glacier expansions during Neoglaciation occurred in the late Little Ice Age. The outermost moraines are adjacent to mature forest stands and bog peats that yield dates as old as 5,600 BP. Prince William Sound glaciers advanced during two Little Ice Age cold periods, 1380-1680 and 1830-1900 AD. The terrestrial glaciers around the Blackstone-Spencer Ice Complex all built moraines during the 19th century and began retreating between 1875 and 1900 AD. Portage and Burns glaciers began retreating between 1790 and 1810 AD, but their margins remained close to the outermost moraines during the 19th century. Regional glacier fluctuations are broadly synchronous in the Gulf of Alaska region. With the exception of the two tidewater glaciers in Blackstone Bay, all glaciers in the Kenai Mountains, no matter their sizes, altitudes, orientations, or types of margins, retreated at the end of the Little Ice Age. The climate signal, especially temperature, appears to be the strongest control on glacier

  20. Beach ridges as paleoseismic indicators of abrupt coastal subsidence during subduction zone earthquakes, and implications for Alaska-Aleutian subduction zone paleoseismology, southeast coast of the Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Kelsey, Harvey M.; Witter, Robert C.; Engelhart, Simon E.; Briggs, Richard; Nelson, Alan R.; Haeussler, Peter J.; Corbett, D. Reide

    2015-01-01

    The Kenai section of the eastern Alaska-Aleutian subduction zone straddles two areas of high slip in the 1964 great Alaska earthquake and is the least studied of the three megathrust segments (Kodiak, Kenai, Prince William Sound) that ruptured in 1964. Investigation of two coastal sites in the eastern part of the Kenai segment, on the southeast coast of the Kenai Peninsula, identified evidence for two subduction zone earthquakes that predate the 1964 earthquake. Both coastal sites provide paleoseismic data through inferred coseismic subsidence of wetlands and associated subsidence-induced erosion of beach ridges. At Verdant Cove, paleo-beach ridges record the paleoseismic history; whereas at Quicksand Cove, buried soils in drowned coastal wetlands are the primary indicators of paleoearthquake occurrence and age. The timing of submergence and death of trees mark the oldest earthquake at Verdant Cove that is consistent with the age of a well documented ∼900-year-ago subduction zone earthquake that ruptured the Prince William Sound segment of the megathrust to the east and the Kodiak segment to the west. Soils buried within the last 400–450 years mark the penultimate earthquake on the southeast coast of the Kenai Peninsula. The penultimate earthquake probably occurred before AD 1840 from its absence in Russian historical accounts. The penultimate subduction zone earthquake on the Kenai segment did not rupture in conjunction with the Prince William Sound to the northeast. Therefore the Kenai segment, which is presently creeping, can rupture independently of the adjacent Prince William Sound segment that is presently locked.

  1. Heavy metals in seaducks and mussels from misty fjords national monument in Southeast Alaska.

    PubMed

    Franson, J C; Koehl, P S; Derksen, D V; Rothe, T C; Bunck, C M; Moore, J F

    1995-06-01

    Quartz Hill, in Misty Fjords National Monument near Ketchikan, Alaska, is the site of a proposed molybdenum-producing mine. To provide baseline data for use in post-development comparisons, we analyzed tissues of Barrow's goldeneyes (Bucephala islandica), common mergansers (Mergus merganser), and blue mussels (Mytilus edulis) for seven heavy metals that could potentially be released into the environment as a result of mining operations. Specimens were collected in 1980, 1981, and 1982 from two fjords likely to be used for discharge of tailings from the proposed mine and from two control fjords. Concentrations of arsenic, cadmium, copper, chromium, molybdenum, lead, and zinc were measured in soft tissues of mussels and in kidney, liver, and muscle of birds. The highest mean concentrations of metals found in bird tissues were 55.7 ppm dry weight cadmium in kidneys and 154 ppm dry weight zinc in livers of Barrow's goldeneyes. Concentrations of several metals in blue mussels differed among seasons and locations, but the most significant finding in mussels was a maximum mean cadmium concentration of 9.6 ppm dry weight, a level higher than normally found in undisturbed areas. With the exception of 104 ppm dry weight cadmium in the kidney of one common merganser and 12.7 ppm dry weight lead in the kidney of another, concentrations of other metals in seaduck and mussel tissues were low, consistent with what would be expected for a pre-development environment. Molybdenum was found in low concentrations (<10 ppm dry weight) in all avian kidney samples and most liver samples, but was not detected in blue mussels.

  2. Heavy metals in seaducks and mussels from Misty Fjords National Monument in southeast Alaska

    USGS Publications Warehouse

    Franson, J.C.; Koehl, P.S.; Derksen, D.V.; Rothe, T.C.; Bunck, C.M.; Moore, J.F.

    1995-01-01

    Quartz Hill, in Misty Fjords National Monument near Ketchikan, Alaska, is the site of a proposed molybdenum-producing mine. To provide baseline data for use in post-development comparisons, we analyzed tissues of Barrow's goldeneyes (Bucephala islandica), common mergansers (Mergus merganser), and blue mussels (Mytilus edulis) for seven heavy metals that could potentially be released into the environment as a result of mining operations. Specimens were collected in 1980, 1981, and 1982 from two fjords likely to be used for discharge of tailings from the proposed mine and from two control fjords. Concentrations of arsenic, cadmium, copper, chromium, molybdenum, lead, and zinc were measured in soft tissues of mussels and in kidney, liver, and muscle of birds. The highest mean concentrations of metals found in bird tissues were 55.7 ppm dry weight cadmium in kidneys and 154 ppm dry weight zinc in livers of Barrow's goldeneyes. Concentrations of several metals in blue mussels differed among seasons and locations, but the most significant finding in mussels was a maximum mean cadmium concentration of 9.6 ppm dry weight, a level higher than normally found in undisturbed areas. With the exception of 104 ppm dry weight cadmium in the kidney of one common merganser and 12.7 ppm dry weight lead in the kidney of another, concentrations of other metals in seaduck and mussel tissues were low, consistent with what would be expected for a pre-development environment. Molybdenum was found in low concentrations ( 10 ppm dry weight) in all avian kidney samples and most liver samples, but was not detected in blue mussels.

  3. Glacimarine sedimentary processes, facies and morphology of the south-southeast Alaska shelf and fjords

    USGS Publications Warehouse

    Powell, R.D.; Molnia, B.F.

    1989-01-01

    High precipitation from Gulf of Alaska air masses can locally reach up to 800 cm a-1. This precipitation on tectonically active mountains creates cool-temperate glaciation with extremely active erosion and continuously renewed resources. High basal debris loads up to 1.5 m thick of pure debris and rapid glacial flow, which can be more than 3000 m a-1, combine to produce large volumes of siliciclastic glacimarine sediment at some of the highest sediment accumulation rates on record. At tidewater fronts of valley glaciers, sediment accumulation rates can be over 13 m a-1 and deltas commonly grow at about 106 m3 a-1. Major processes influencing glacimarine sedimentation are glacial transport and glacier-contact deposition, meltwater (subaerial and submarine) and runoff transport and deposition, iceberg rafting and gouging, sea-ice transport, wave action and storm reworking, tidal transport and deposition, alongshelf transport, sliding and slumping and gravity flows, eolian transport, and biogenic production and reworking. Processes are similar in both shelf and fjord settings; however, different intensities of some processes create different facies associations and geometries. The tectonoclimatic regime also controls morphology because bedrock structure is modified by glacial action. Major glacimarine depositional systems are all siliciclastic. They are subglacial, marginal-morainal bank and submarine outwash, and proglacial/paraglacial-fluvial/deltaic, beach, tidal flat/estuary, glacial fjord, marine outwash fjord and continental shelf. Future research should include study of long cores with extensive dating and more seismic surveys to evaluate areal and temporal extent of glacial facies and glaciation; time-series oceanographic data, sidescan sonar surveys and submersible dives to evaluate modern processes; biogenic diversity and production to evaluate paleoecological, paleobiogeographic and biofacies analysis; and detailed comparisons of exposed older rock of the

  4. Seismic reflection characteristics of glacial and glacimarine sediment in the Gulf of Alaska and adjacent fjords

    USGS Publications Warehouse

    Carlson, P.R.

    1989-01-01

    Glaciation together with tectonism have been dominant factors affecting sedimentation in the Gulf of Alaska area from at least the late Miocene throughout the Quaternary. The effects of tectonism are apparent in high mountains that border the gulf, raised terraces of Middleton Island and the eastern gulf coastal zone, and numerous active faults and related earthquakes. Glacial evidence includes magnificent glaciers and their onshore deposits, spectacular fjords, large sea valleys incised in the continental shelf, submarine morainal ridges at mouths of bays and sea valleys, and thick glacimarine sedimentary sequences (diamicts) that are exposed onshore and at the sea floor along the outer shelf. Seismic-reflection profiling and sampling of the uppermost marine sedimentary sequences in the Gulf of Alaska and adjacent fjords and bays have allowed identification of three discrete glacially related stratigraphic units. These units were delineated on the basis of seismic signature, geometry, physiographic location, stratigraphic position, and sedimentologic characteristics. The oldest unit, a Quaternary diamict, is portrayed on seismic profiles by irregular, discontinuous reflections. This unit probably includes till, outwash and glacimarine sediment. A geographically restricted unit, one incorporating Holocene end moraines at bay mouths and associated with some sea valleys, consists of jumbled masses of discontinuous reflections and very irregular surface morphology. The youngest unit, a blanket of Holocene sand to clayey silt prograding as a sediment wedge across the shelf, contains nearly horizontal, parallel reflections except where disrupted by mass movement. Although seismic-reflection data alone cannot provide definitive proof of the presence of glacial sediment, when combined with sea-floor sampling, seismic profiling is a powerful tool for determining the continuity of marine sedimentary units and relationships to past and modern glaciers. ?? 1989.

  5. Oceanography of Glacier Bay, Alaska: Implications for biological patterns in a glacial fjord estuary

    USGS Publications Warehouse

    Etherington, L.L.; Hooge, P.N.; Hooge, E.R.; Hill, D.F.

    2007-01-01

    Alaska, U.S.A, is one of the few remaining locations in the world that has fjords that contain temperate idewater glaciers. Studying such estuarine systems provides vital information on how deglaciation affects oceanographic onditions of fjords and surrounding coastal waters. The oceanographic system of Glacier Bay, Alaska, is of particular interest ue to the rapid deglaciation of the Bay and the resulting changes in the estuarine environment, the relatively high oncentrations of marine mammals, seabirds, fishes, and invertebrates, and the Bay’s status as a national park, where ommercial fisheries are being phased out. We describe the first comprehensive broad-scale analysis of physical and iological oceanographic conditions within Glacier Bay based on CTD measurements at 24 stations from 1993 to 2002. easonal patterns of near-surface salinity, temperature, stratification, turbidity, and euphotic depth suggest that freshwater nput was highest in summer, emphasizing the critical role of glacier and snowmelt to this system. Strong and persistent tratification of surface waters driven by freshwater input occurred from spring through fall. After accounting for seasonal nd spatial variation, several of the external physical factors (i.e., air temperature, precipitation, day length) explained a large mount of variation in the physical properties of the surface waters. Spatial patterns of phytoplankton biomass varied hroughout the year and were related to stratification levels, euphotic depth, and day length. We observed hydrographic atterns indicative of strong competing forces influencing water column stability within Glacier Bay: high levels of freshwater ischarge promoted stratification in the upper fjord, while strong tidal currents over the Bay’s shallow entrance sill enhanced ertical mixing. Where these two processes met in the central deep basins there were optimal conditions of intermediate tratification, higher light levels, and potential nutrient renewal

  6. Kinematic analysis of melange fabrics: Examples and applications from the McHugh Complex, Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Kusky, T.M.; Bradley, D.C.

    1999-01-01

    Permian to Cretaceous melange of the McHugh Complex on the Kenai Peninsula, south-central Alaska includes blocks and belts of graywacke, argillite, limestone, chert, basalt, gabbro, and ultramafic rocks, intruded by a variety of igneous rocks. An oceanic plate stratigraphy is repeated hundreds of times across the map area, but most structures at the outcrop scale extend lithological layering. Strong rheological units occur as blocks within a matrix that flowed around the competent blocks during deformation, forming broken formation and melange. Deformation was noncoaxial, and disruption of primary layering was a consequence of general strain driven by plate convergence in a relatively narrow zone between the overriding accretionary wedge and the downgoing, generally thinly sedimented oceanic plate. Soft-sediment deformation processes do not appear to have played a major role in the formation of the melange. A model for deformation at the toe of the wedge is proposed in which layers oriented at low angles to ??1 are contracted in both the brittle and ductile regimes, layers at 30-45??to ??1 are extended in the brittle regime and contracted in the ductile regime, and layers at angles greater than 45??to ??1 are extended in both the brittle and ductile regimes. Imbrication in thrust duplexes occurs at deeper levels within the wedge. Many structures within melange of the McHugh Complex are asymmetric and record kinematic information consistent with the inferred structural setting in an accretionary wedge. A displacement field for the McHugh Complex on the lower Kenai Peninsula includes three belts: an inboard belt of Late Triassic rocks records west-to-east-directed slip of hanging walls, a central belt of predominantly Early Jurassic rocks records north-south directed displacements, and Early Cretaceous rocks in an outboard belt preserve southwest-northeast directed slip vectors. Although precise ages of accretion are unknown, slip directions are compatible with

  7. Kinematic analysis of mélange fabrics: examples and applications from the McHugh Complex, Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Kusky, Timothy M.; Bradley, Dwight C.

    1999-12-01

    Permian to Cretaceous mélange of the McHugh Complex on the Kenai Peninsula, south-central Alaska includes blocks and belts of graywacke, argillite, limestone, chert, basalt, gabbro, and ultramafic rocks, intruded by a variety of igneous rocks. An oceanic plate stratigraphy is repeated hundreds of times across the map area, but most structures at the outcrop scale extend lithological layering. Strong rheological units occur as blocks within a matrix that flowed around the competent blocks during deformation, forming broken formation and mélange. Deformation was noncoaxial, and disruption of primary layering was a consequence of general strain driven by plate convergence in a relatively narrow zone between the overriding accretionary wedge and the downgoing, generally thinly sedimented oceanic plate. Soft-sediment deformation processes do not appear to have played a major role in the formation of the mélange. A model for deformation at the toe of the wedge is proposed in which layers oriented at low angles to σ1 are contracted in both the brittle and ductile regimes, layers at 30-45° to σ1 are extended in the brittle regime and contracted in the ductile regime, and layers at angles greater than 45° to σ1 are extended in both the brittle and ductile regimes. Imbrication in thrust duplexes occurs at deeper levels within the wedge. Many structures within mélange of the McHugh Complex are asymmetric and record kinematic information consistent with the inferred structural setting in an accretionary wedge. A displacement field for the McHugh Complex on the lower Kenai Peninsula includes three belts: an inboard belt of Late Triassic rocks records west-to-east-directed slip of hanging walls, a central belt of predominantly Early Jurassic rocks records north-south directed displacements, and Early Cretaceous rocks in an outboard belt preserve southwest-northeast directed slip vectors. Although precise ages of accretion are unknown, slip directions are compatible with

  8. 76 FR 58263 - Kenai Pipe Line Company; Tesoro Alaska Company; Tesoro Logistics Operations, LLC; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ... Requirements. Tesoro requests that the Commission determine that two crude oil pipelines, as well as several crude oil and refined petroleum products pipeline spurs that are part of Tesoro Alaska's...

  9. Reflected and mode-converted seismic waves within the shallow Aleutian subduction zone, southern Kenai Peninsula, Alaska

    SciTech Connect

    Stephens, C.D.; Page, R.A.; Lahr, J.C. )

    1990-05-10

    Pronounced secondary phases observed in local recordings of quarry shots and earthquakes on the southern Kenai Peninsula, Alaska, are identified as reflected P and S and converted S-to-P phases originating within four depth ranges: in the upper few kilometers of the Cook Inlet Tertiary basin, at midcrustal depths within the overthrust North American plate, at about 35 km depth near the top of the Wadati-Benioff seismic zone in proximity to the inferred interplate megathrust, and at about 5-10 km below the megathrust in the subducted Pacific plate. Beneath the landward margin of the accreted Chugach terrane, the mid-upper plate (MUP) discontinuity dips as steeply as 20{degree}-30{degree} to the west-northwest over the depth range 12-18 km. At shallower depths it flattens and possibly arches with the crest at about 10 km depth. Similar midcrustal reflectors have been imaged about 125 km to the southwest and about 350 km to the northeast along the structural trend of the Chugach terrane. The extensive reflectors may have a common origin, possibly caused by the presence of underplated rocks. Relative amplitudes and polarities of the secondary phases originating at MUP depths provide few constraints on the nature of the discontinuity. It appears that the MUP discontinuity is seismically inactive and does not represent a brittle-ductile transition zone within the upper plate. The two converted S-to-P phases generated near the top of the subducted plate could indicate a low-velocity zone associated with subducted oceanic crust.

  10. White Spruce Regeneration Following a Major Spruce Beetle Outbreak in Forests on the Kenai Peninsula, Alaska

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Between 1987 and 2000, a spruce beetle (Dendroctonus rufipennis) epidemic infested 1.19 million hectares of spruce (Picea spp.) forests in Alaska, killing most of the large diameter trees. We evaluated whether these forests would recover to their pre-outbreak density, and determined the site conditi...

  11. Holocene evolution of diatom and silicoflagellate paleoceanography in Slocum Arm, a fjord in southeastern Alaska

    USGS Publications Warehouse

    Barron, John A.; Bukry, John D.; Addison, Jason A.; Ager, Thomas A.

    2016-01-01

    Diatom and silicoflagellate assemblages in cores EW0408-47JC, -47TC, -46MC (57° 34.5278′ N, 136° 3.7764′ W, 114 m water depth) taken from the outer portion of Slocum Arm, a post-glacial fjord in southeastern Alaska, reveal the paleoclimatic and paleoceanographic evolution of the eastern margin of the Gulf of Alaska (GoA) during the past 10,000 years. Between ~ 10 and 6.8 cal ka, periods of low salinity and cool water conditions alternated with brief intervals marked by the increased influx of oceanic, more saline and likely warmer waters. Increased surface water stability characterized by a middle Holocene interval between ~ 6.8 and 3.2 cal ka is typified by increased abundances of northeastern Pacific Thalassiosira spp. that are indicative of spring coastal blooms and decreased abundances of warm and higher salinity oceanic diatoms. At ~ 3.2 cal ka, an abrupt increase in both the relative contribution of oceanic diatoms and silicoflagellates suggestive of cooler upwelling conditions occurred in the -47JC record. A stepwise increase in alkenone sea surface temperature in northern GoA core EW0408-85JC and increase in southern sourced precipitation in the carbonate δ18O record of Jellybean Lake (Yukon) present evidence that this ~ 3.2 cal ka event coincided with the onset of enhanced positive Pacific Decadal Oscillation-like (PDO) conditions in the GoA. These positive PDO-like conditions persisted until ~ 1.0 cal ka and were followed by high amplitude fluctuations in the relative abundance of diatom and silicoflagellate assemblages.

  12. Accretion in the wake of terrane collision: The Neogene accretionary wedge off Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Fruehn, J.; Von Huene, R.; Fisher, M.A.

    1999-01-01

    Subduction accretion and repeated terrane collision shaped the Alaskan convergent margin. The Yakutat Terrane is currently colliding with the continental margin below the central Gulf of Alaska. During the Neogene the terrane's western part was subducted after which a sediment wedge accreted along the northeast Aleutian Trench. This wedge incorporates sediment eroded from the continental margin and marine sediments carried into the subduction zone on the Pacific plate. Prestack depth migration was performed on six seismic reflection lines to resolve the structure within this accretionary wedge and its backstop. The lateral extent of the structures is constrained by high-resolution swath bathymetry and seismic lines collected along strike. Accretionary structure consists of variably sized thrust slices that were deformed against a backstop during frontal accretion and underplating. Toward the northeast the lower slope steepens, the wedge narrows, and the accreted volume decreases notwith-standing a doubling of sediments thickness in the trench. In the northeasternmost transect, near the area where the terrane's trailing edge subducts, no frontal accretion is observed and the slope is eroded. The structures imaged along the seismic lines discussed here most likely result from progressive evolution from erosion to accretion, as the trailing edge of the Yakutat Terrane is subducting.

  13. Digital Data for the Reconnaissance Geologic Map for Prince William Sound and the Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Digital Files Preparation: Wilson, Frederic H.; Hults, Chad P.; Labay, Keith A.; Shew, Nora; Geologic Map Compilers: Wilson, Frederic H.

    2007-01-01

    INTRODUCTION The growth in the use of Geographic Information Systems (GIS) has highlighted the need for digital geologic maps that have been attributed with information about age and lithology. Such maps can be conveniently used to generate derivative maps for manifold special purposes such as mineral-resource assessment, metallogenic studies, tectonic studies, and environmental research. This report is part of a series of integrated geologic map databases that cover the entire United States. Three national-scale geologic maps that portray most or all of the United States already exist; for the conterminous U.S., King and Beikman (1974a,b) compiled a map at a scale of 1:2,500,000, Beikman (1980) compiled a map for Alaska at 1:2,500,000 scale, and for the entire U.S., Reed and others (2005a,b) compiled a map at a scale of 1:5,000,000. A digital version of the King and Beikman map was published by Schruben and others (1994). Reed and Bush (2004) produced a digital version of the Reed and others (2005a) map for the conterminous U.S. The present series of maps is intended to provide the next step in increased detail. State geologic maps that range in scale from 1:100,000 to 1:1,000,000 are available for most of the country, and digital versions of these state maps are the basis of this product. The digital geologic maps presented here are in a standardized format as ARC/INFO export files and as ArcView shape files. The files named __geol contain geologic polygons and line (contact) attributes; files named __fold contain fold axes; files named __lin contain lineaments; and files named __dike contain dikes as lines. Data tables that relate the map units to detailed lithologic and age information accompany these GIS files. The map is delivered as a set 1:250,000-scale quadrangle files. To the best of our ability, these quadrangle files are edge-matched with respect to geology. When the maps are merged, the combined attribute tables can be used directly with the merged

  14. Submarine sedimentary features on a fjord delta front, Queen Inlet, Glacier Bay, Alaska

    USGS Publications Warehouse

    Carlson, P.R.; Powell, R.D.; Phillips, A.C.

    1992-01-01

    Side-scan sonar images provide a view of an actively changing delta front in this marine outwash fjord. Numerous interconnected gullies and chute-like small channels form paths for the transport of sand and coarse silt from the braided glacial outwash streams on the delta plain to the sinuous turbidity-current channels incised into the fjord floor. These turbidity-current channels carry coarse sediment through the fjord and into the adjoining glacial trunk valley. Several sedimentary processes affect the development of this delta front: overflow plumes deposit fine sediment; sediment gravity flows result from episodic delivery of large loads of coarse sediment; and mass movement may be triggered by earthquakes and, more regularly, by spring-tidal drawdown or hydraulic loading. -Authors

  15. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  16. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  17. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  18. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  19. 46 CFR 7.165 - Kenai Peninsula, AK to Kodiak Island, AK.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Kenai Peninsula, AK to Kodiak Island, AK. 7.165 Section... BOUNDARY LINES Alaska § 7.165 Kenai Peninsula, AK to Kodiak Island, AK. (a) A line drawn from the southernmost extremity of Kenai Peninsula at longitude 151°44.0′ W. to East Amatuli Island Light; thence to...

  20. Reflected and mode-converted seismic waves within the shallow aleutian subduction zone, southern Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Stephens, C.D.; Page, R.A.; Lahr, J.C.

    1990-01-01

    Pronounced secondary phases observed in local recordings of quarry shots and earthquakes on the southern Kenai Peninsula are identified as reflected P and S and converted S-to-P phases originating within four depth ranges: in the upper few kilometers of the Cook Inlet Tertiary basin, at midcrustal depths within the overthrust North American plate, at about 35 km depth near the top of the Wadati-Benioff seismic zone in proximity to the inferred interplate megathrust, and at about 5-10 km below the megathrust in the subducted Pacific plate. The positions and origins of the mid-upper plate (MUP) discontinuity and similar reflectors are discussed. It appears the the MUP discontinuity is seismically inactive and does not represent a brittle-ductile transition zone within the upper plate. The two converted S-to-P phases generated near the top of the subducted plate could indicate a low velocity zone associated with subducted oceanic crust. -after Authors

  1. Determining baselines and variability of elements in plants and soils near the Kenai National Wildlife Refuge, Alaska

    USGS Publications Warehouse

    Crock, J.G.; Severson, R.C.; Gough, L.P.

    1992-01-01

    Recent investigations on the Kenai Peninsula had two major objectives: (1) to establish elemental baseline concentrations ranges for native vegetation and soils; and, (2) to determine the sampling density required for preparing stable regional geochemical maps for various elements in native plants and soils. These objectives were accomplished using an unbalanced, nested analysis-of-variance (ANOVA) barbell sampling design. Hylocomium splendens (Hedw.) BSG (feather moss, whole plant), Picea glauca (Moench) Voss (white spruce, twigs and needles), and soil horizons (02 and C) were collected and analyzed for major and trace total element concentrations. Using geometric means and geometric deviations, expected baseline ranges for elements were calculated. Results of the ANOVA show that intensive soil or plant sampling is needed to reliably map the geochemistry of the area, due to large local variability. For example, producing reliable element maps of feather moss using a 50 km cell (at 95% probability) would require sampling densities of from 4 samples per cell for Al, Co, Fe, La, Li, and V, to more than 15 samples per cell for Cu, Pb, Se, and Zn.Recent investigations on the Kenai Peninsula had two major objectives: (1) to establish elemental baseline concentrations ranges for native vegetation and soils; and, (2) to determine the sampling density required for preparing stable regional geochemical maps for various elements in native plants and soils. These objectives were accomplished using an unbalanced, nested analysis-of-variance (ANOVA) barbell sampling design. Hylocomium splendens (Hedw.) BSG (feather moss, whole plant), Picea glauca (Moench) Voss (white spruce, twigs and needles), and soil horizons (02 and C) were collected and analyzed for major and trace total element concentrations. Using geometric means and geometric deviations, expected baseline ranges for elements were calculated. Results of the ANOVA show that intensive soil or plant sampling is needed to

  2. Slide-induced waves, seiching and ground fracturing caused by the earthquake of March 27, 1964 at Kenai Lake, Alaska: Chapter A in The Alaska earthquake, March 27, 1964: regional effects

    USGS Publications Warehouse

    McCulloch, David S.

    1966-01-01

    The March 27, 1964, earthquake dislodged slides from nine deltas in Kenai Lake, south-central Alaska. Sliding removed protruding parts of deltas-often the youngest parts-and steepened delta fronts, increasing the chances of further sliding. Fathograms show that debris from large slides spread widely over the lake floor, some reaching the toe of the opposite shore; at one place debris traveled 5,000 feet over the horizontal lake floor. Slides generated two kinds of local waves: a backfill and far-shore wave. Backfill waves were formed by water that rushed toward the delta to fill the void left by the sinking slide mass, overtopped the slide scrap, and came ashore over the delta. Some backfill waves had runup heights of 30 feet and ran inland more than 300 feet, uprooting and breaking off large trees. Far-shore waves hit the shore opposite the slides. They were formed by slide debris that crossed the lake floor and forced water ahead of it, which then ran up the opposite slope, burst above the lake surface, and struck the shore. One far-shore wave had a runup height of 72 feet. Kenai Lake was tilted and seiched; a power spectrum analysis of a limnogram shows a wave having the period of the calculated uninodal seiche (36 minutes) and several shorter period waves. In constricted and shallow reaches, waves caused by seiching had 20- and 30-foot runup heights. Deep lateral spreading of sediments toward delta margins displaced deeply driven railroad-bridge piles, and set up stress fields in the surface sediments which resulted in the formation of many shear and some tension fractures on the surface of two deltas.

  3. Oceanographic gradients and seabird prey community dynamics in glacial fjords

    USGS Publications Warehouse

    Arimitsu, Mayumi L.; Piatt, John F.; Madison, Erica N.; Conaway, Jeff; Hillgruber, N.

    2012-01-01

    Glacial fjord habitats are undergoing rapid change as a result of contemporary global warming, yet little is known about how glaciers influence marine ecosystems. These ecosystems provide important feeding, breeding and rearing grounds for a wide variety of marine organisms, including seabirds of management concern. To characterize ocean conditions and marine food webs near tidewater glaciers, we conducted monthly surveys of oceanographic variables, plankton, fish and seabirds in Kenai Fjords, Alaska, from June to August of 2007 and 2008. We also measured tidal current velocities near glacial features. We found high sediment load from glacial river runoff played a major role in structuring the fjord marine ecosystem. Submerged moraines (sills) isolated cool, fresh, stratified and silt-laden inner fjord habitats from oceanic influence. Near tidewater glaciers, surface layers of turbid glacial runoff limited availability of light to phytoplankton, but macrozooplankton were abundant in surface waters, perhaps due to the absence of a photic cue for diel migration. Fish and zooplankton community structure varied along an increasing temperature gradient throughout the summer. Acoustic measurements indicated that low density patches of fish and zooplankton were available in the surface waters near glacial river outflows. This is the foraging habitat occupied most by Kittlitz's murrelet (Brachyramphus brevirostris), a rare seabird that appears to be specialized for life in glacially influenced environments. Kittlitz's murrelets were associated with floating glacial ice, and they were more likely to occur near glaciers, in deeper water, and in areas with high acoustic backscatter. Kittlitz's murrelet at-sea distribution was limited to areas influenced by turbid glacial outflows, and where prey was concentrated near the surface in waters with low light penetration. Tidewater glaciers impart unique hydrographic characteristics that influence marine plankton and fish

  4. Paleo-tsunami and Tephrochronologic Investigations into the Late Holocene Volcanic History of Augustine Volcano on the Southwest Coast of the Kenai Peninsula, Lower Cook Inlet Alaska

    NASA Astrophysics Data System (ADS)

    Maharrey, J. Z.; Beget, J. E.; Wallace, K.

    2014-12-01

    Augustine Volcano, a small island volcano located in Cook Inlet, Alaska has produced approximately 11 flank-failure debris-avalanches over the last 2,000 yrs (BP) that were large enough to reach the coast of the island and enter the sea. Each debris avalanche conceivably could have triggered a tsunami. In 1883, a tsunami generated by an eruption and flank-failure of Augustine inundated the indigenous Alaskan village of Nanwalek (previously English Bay) with 8 meters of runup. Nanwalek is geographically located atop a coastal headland on the southwest coast of the Kenai Peninsula approximately 85 kilometers due east of Augustine (Beget et al., 2008). Current research in Nanwalek is focused on describing a peat exposure situated on the shoreward edge of the English Bay headland. We present new data from this locality on the sedimentology, tephrochronology, radiocarbon dating, and field stratigraphy. The exposure is basally dated to approximately 7,100 yr BP and includes exotic units of volcanic ash, sand, and gravel. We correlate 19 tephra layers to late Holocene eruptions of Augustine and several Cook Inlet and northern Alaska Peninsula volcanoes. We interpret the non-volcanic clastic sediment horizons in the peat as prehistoric tsunami-inundation events of the English Bay headland. Augustine volcanic-ash deposits found within the tsunami deposits allow correlation to prehistoric coeval flank-failure debris-avalanche deposits exposed on Augustine (Waitt and Beget, 2009). We correlate three tsunami deposits associated with Augustine tephra marker horizons H, I, and G of Waitt and Beget (2009) each of which were erupted approximately 1,400 yr BP, 1,700 yr BP, and 2,100 yr BP. Additionally, we present new tephra and sedimentological evidence for a 4,100 yr BP paleo-tsunami inundation event at Nanwalek that we correlate to a previously unidentified flank-failure debris-avalanche event at Augustine Volcano. The recognition of this new deposit extends the age record for

  5. Trends and Controls on Summer Surface-Water Temperatures in Salmonid-Bearing Headwater Streams in Two Common Geomorphic Settings, Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Callahan, M. K.; Bellino, J. C.; Rains, M. C.

    2010-12-01

    Stream temperature is an important physical characteristic of headwater streams that plays a critical role in the presence and health of juvenile salmonids. Headwater stream temperature was documented in two geomorphic settings on the Kenai Peninsula, Alaska, focusing on the variation in temperature induced by diffuse groundwater discharge and variable air temperature. Eighteen headwater stream reaches were studied in four watersheds, with 11 drainageway sites and seven discharge-slope sites. In drainageway sites, low-gradient streams flow through broad valleys with groundwater-fed fen wetlands; in discharge-slope sites, high-gradient streams flow through narrow valleys with groundwater-fed slope wetlands. At all 18 sites, hourly stream temperatures were measured for one year. At one drainageway and one discharge-slope site, groundwater temperatures, stream stages, and groundwater heads in the local groundwater flow systems were also measured hourly for a year. A process-based, mechanistic surface-water temperature model (SSTEMP) was used to identify the importance of surface-water temperature controls, particularly the role of groundwater discharge and air temperature, at the two highly instrumented sites. The contribution of groundwater to flow was calculated using a mass-balance water quality mixing model. Groundwater discharge represented 40-60 percent of total stream flow in both geomorphic settings. However, stream and groundwater temperature characteristics differed between the two geomorphic settings. Stream and groundwater temperatures were tightly coupled in the discharge-slope site but not in the drainageway site. Furthermore, warmer stream temperatures occurred at the drainageway site compared to the discharge-slope site, especially during the late summer. SSTEMP simulations indicate that diffuse groundwater discharge does not greatly affect changes in stream temperature at either geomorphic setting, corroborating field observations that focused

  6. Direct measurements by submersible of surge-type turbidity currents in a fjord channel, southeast Alaska

    SciTech Connect

    Cowan, E.A. . Dept. of Geology); Powell, R.D. . Geology Dept.); Lawson, D.E. ); Carlson, P.R. )

    1992-01-01

    High density, high-speed turbidity currents were observed and their properties measured in submarine channels in Queen Inlet, southeast Alaska during June, 1990 and 1991. A ROV submersible fitted with two video cameras, a CTD, an optical backscatter turbidity monitor (OBS), and electromagnetic current meter, and sidescan sonar was used to collect data from within and above the flows. Multiple flows were recorded during a ROV dive at 2.3 km from the delta front in a channel at 104 m depth. Flows were marked by sudden increases in turbidity and current velocity. In one flow, turbidity increased from 300 to 1,600 OBS units (instrument maximum) in 10 sec, and within 9.4 min, salinity (S) steadily decreased by 12.1 ppt, with only a 0.2 C temperature (T) increase. Density differences between the flow and ambient water require a minimum sediment concentration of 97 g/l. Maximum flow velocity exceeded 3.3 m/s. A vertical ROV profile indicated a flow thickness of 10 m. The upper surface was visually identified by billowing suspended sediment and by fluctuating OBS and T as ambient and flow water mixed in turbulent eddies. A faster S decrease and slower T increase with distance into and away from the flow indicate that thermal diffusive processes were less efficient than convective mass transfer. The S change indicates that flow water and ambient water mixed well beyond the flow defined by high turbidity. Warm water temperatures within the flow and low meltwater stream discharge suggest that these flows originated from the delta front and are not continuous underflows.

  7. Object-Based Image Classification of Floating Ice Used as Habitat for Harbor Seals in a Tidewater Glacier Fjord in Alaska

    NASA Astrophysics Data System (ADS)

    McNabb, R. W.; Womble, J. N.; Prakash, A.; Gens, R.; Ver Hoef, J.

    2014-12-01

    Tidewater glaciers play an important role in many landscape and ecosystem processes in fjords, terminating in the sea and calving icebergs and discharging meltwater directly into the ocean. Tidewater glaciers provide floating ice for use as habitat for harbor seals (Phoca vitulina richardii) for resting, pupping, nursing, molting, and avoiding predators. Tidewater glaciers are found in high concentrations in Southeast and Southcentral Alaska; currently, many of these glaciers are retreating or have stabilized in a retracted state, raising questions about the future availability of ice in these fjords as habitat for seals. Our primary objective is to investigate the relationship between harbor seal distribution and ice availability at an advancing tidewater glacier in Johns Hopkins Inlet, Glacier Bay National Park, Alaska. To this end, we use a combination of visible and infrared aerial photographs, object-based image analysis (OBIA), and statistical modeling techniques. We have developed a workflow to automate the processing of the imagery and the classification of the fjordscape (e.g., individual icebergs, brash ice, and open water), providing quantitative information on ice coverage as well as properties not typically found in traditional pixel-based classification techniques, such as block angularity and seal density across the fjord. Reflectance variation in the red channel of the optical images has proven to be the most important first-level criterion to separate open water from floating ice. This first-level criterion works well in areas without dense brash ice, but tends to misclassify dense brash ice as single icebergs. Isolating these large misclassified regions and applying a higher reflectance threshold as a second-level criterion helps to isolate individual ice blocks surrounded by dense brash ice. We present classification results from surveys taken during June and August, 2007-2013, as well as preliminary results from statistical modeling of the

  8. 75 FR 38093 - ConocoPhillips Alaska Natural Gas Corporation and Marathon Oil Company; Application for Blanket...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... 1168, 1176 (5th Cir. 1988). \\4\\ Order No. 1473 at p. 14 citing, Delegation Order No. 0204- 111, 49 FR... natural gas liquefaction and marine terminal facilities near Kenai, Alaska, (Kenai LNG Facility) \\1\\...

  9. Geochemistry of gases from fluid inclusions within gold-quartz veins in the Chugach and Kenai Mountains, south-central Alaska

    SciTech Connect

    Goldfarb, R.J.; Leach, D.L.; Hofstra, A.H.; Landis, G.P.

    1985-01-01

    Gold-bearing quartz veins within the Valdez Group turbidite sequences of the Chugach and Kenai Mountains are largely restricted to areas of medium-grade greenschist facies. The veins postdate accretion, deformation, and peak regional metamorphism of the Valdez Group. Liquid dominant, low salinity (<5 wt.% NaCl equivalent) fluid inclusions in quartz from four mining districts show homogenization temperatures generally ranging from 210/sup 0/ to 280/sup 0/C. Estimated minimum trapping pressures of 1.5 kbar were obtained from quartz decrepitation data. The authors observations tend to support the theory that ore-forming fluids were derived during regional metamorphism. Microthermometry, Raman spectroscopy, and mass spectrometry were used to analyze the volatile components of fluid inclusions from the four districts. Inclusions adjacent to gold and sulfide grains from each district contained 7-10 mole % CO/sub 2/, 0-2 mole % CH/sub 4/, and 0-2 mole % N/sub 2/. Both a pure CO/sub 2/ volatile phase and CO/sub 2/-N/sub 2/-CH/sub 4/ mixtures were consistently observed within quartz embaying intergrown gold and sulfide grains. Gas solubility data and the observed inclusion homogenization temperatures support minimum trapping pressures in approximate agreement with the quartz decrepitation data. The estimated minimum pressures correspond to a minimum depth of vein development at 3.5-5 km under the condition that fluid pressure equals lithostatic pressure. The ubiquitous presence of appreciable and similar dissolved gases, along with the consistent salinities and homogenization temperatures, provide further support for a regional process of ore genesis.

  10. Genetic diversity of sockeye salmon (`oncorhynchus nerka`) of Cook Inlet, Alaska, and its application to restoration of injured populations of the Kenai River. Exxon Valdez Oil Spill Restoration Project 93012 and 94255-2. Final report

    SciTech Connect

    Seeb, L.W.; Habicht, C.; Templin, W.D.; Fetzner, J.W.; Gates, R.B.

    1995-11-01

    Genetic data from sockeye salmon (Oncorhynchus nerka) were collected from all significant spawning populations contributing to mixed-stock harvests in Cook Inlet. A total of 68 allozyme loci were resolved from 37 populations. Mitochondrial DNA data from the NADH subunits 5 and 6 were collected from 19 of the populations. Mixed-stock analyses using maximum likelihood methods with 27 loci were evaluated to estimate the proportion of Kenai River populations in Central District drift fisheries. Simulations indicate that Kenai River populations can be identified in mixtures at a level of precision and accuracy useful for restoration and fishery management. Mixed-stock samples from Cook Inlet drift net fisheries were analyzed both inseason (48 hr) and post-season. Samples from fish wheels from the Kenai, Kasilof, Yentna, and Susitna River systems were also analyzed. Inclusion of mtDNA data in the analysis is being investigated to determine if it improves precision and accuracy. Results from this study are currently being used in the management and restoration of Kenai River sockeye salmon injured in the 1989 Exxon Valdex oil spill.

  11. 75 FR 27775 - Kenai Hydro, LLC; Notice of Scoping Meetings, Environmental Site Review, and Soliciting Scoping...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-18

    ...: Grant Lake, Grand Creek, and Falls Creek on the Kenai Peninsula, near the community of Moose Pass...: Evening Scoping Meeting Date: Wednesday, June 2, 2010. Time: 7 p.m. (Alaska ST). Place: Moose Pass Community Hall. Address: Mile 29.5 Seward Highway, Moose Pass, AK 99631. Daytime Scoping Meeting...

  12. College Fjord, Prince Williams Sound

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The College Fjord with its glaciers was imaged by ASTER on June 24, 2000.

    This image covers an area 20 kilometers (13 miles) wide and 24 kilometers (15 miles) long in three bands of the reflected visible and infrared wavelength region. College Fjord is located in Prince Williams Sound, east of Seward, Alaska. Vegetation is in red, and snow and ice are white and blue. Ice bergs calved off of the glaciers can be seen as white dots in the water. At the head of the fjord, Harvard Glacier (left) is one of the few advancing glaciers in the area; dark streaks on the glacier are medial moraines: rock and dirt that indicate the incorporated margins of merging glaciers. Yale Glacier to the right is retreating, exposing (now vegetated) bedrock where once there was ice. On the west edge of the fjord, several small glaciers enter the water. This fjord is a favorite stop for cruise ships plying Alaska's inland passage.

    This image is located at 61.2 degrees north latitude and 147.7 degrees west longitude.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in

  13. Unusually loud ambient noise in tidewater glacier fjords: a signal of ice melt

    USGS Publications Warehouse

    Pettit, Erin C.; Lee, Kevin M.; Brann, Joel P.; Nystuen, Jeffrey A.; Wilson, Preston S.; O'Neel, Shad

    2015-01-01

    In glacierized fjords, the ice-ocean boundary is a physically and biologically dynamic environment that is sensitive to both glacier flow and ocean circulation. Ocean ambient noise offers insight into processes and change at the ice-ocean boundary. Here we characterize fjord ambient noise and show that the average noise levels are louder than nearly all measured natural oceanic environments (significantly louder than sea ice and non-glacierized fjords). Icy Bay, Alaska has an annual average sound pressure level of 120 dB (re 1 μPa) with a broad peak between 1000 and 3000 Hz. Bubble formation in the water column as glacier ice melts is the noise source, with variability driven by fjord circulation patterns. Measurements from two additional fjords, in Alaska and Antarctica, support that this unusually loud ambient noise in Icy Bay is representative of glacierized fjords. These high noise levels likely alter the behavior of marine mammals.

  14. Fjords: Processes and products

    SciTech Connect

    Syvitski, J.P.M.; Burrell, D.C.; Skei, J.M.

    1987-01-01

    Fjords are a major feature of coasts and provide geologists and oceanographers with an excellent environment for studying and modeling coastal processes and products. This book brings together and integrates an enormous amount of information on fjords and provides the reader with a thorough, interdisciplinary account of current research with emphasis on sedimentary processes. The processes demonstrated in fjords are often relevant to the estuarine or open ocean environment.

  15. Quantifying the Availability of Tidewater Glacial Ice as Habitat for Harbor Seals in a Tidewater Glacial Fjord in Alaska Using Object-Based Image Analysis of Airborne Visible Imagery

    NASA Astrophysics Data System (ADS)

    Prakash, A.; Haselwimmer, C. E.; Gens, R.; Womble, J. N.; Ver Hoef, J.

    2013-12-01

    Tidewater glaciers are prominent landscape features that play a significant role in landscape and ecosystem processes along the southeastern and southcentral coasts of Alaska. Tidewater glaciers calve large icebergs that serve as an important substrate for harbor seals (Phoca vitulina richardii) for resting, pupping, nursing young, molting, and avoiding predators. Many of the tidewater glaciers in Alaska are retreating, which may influence harbor seal populations. Our objectives are to investigate the relationship between ice conditions and harbor seal distributions, which are poorly understood, in John's Hopkins Inlet, Glacier Bay National Park, Alaska, using a combination of airborne remote sensing and statistical modeling techniques. We present an overview of some results from Object-Based Image Analysis (OBIA) for classification of a time series of very high spatial resolution (4 cm pixels) airborne imagery acquired over John's Hopkins Inlet during the harbor seal pupping season in June and during the molting season in August from 2007 - 2012. Using OBIA we have developed a workflow to automate processing of the large volumes (~1250 images/survey) of airborne visible imagery for 1) classification of ice products (e.g. percent ice cover, percent brash ice, percent ice bergs) at a range of scales, and 2) quantitative determination of ice morphological properties such as iceberg size, roundness, and texture that are not found in traditional per-pixel classification approaches. These ice classifications and morphological variables are then used in statistical models to assess relationships with harbor seal abundance and distribution. Ultimately, understanding these relationships may provide novel perspectives on the spatial and temporal variation of harbor seals in tidewater glacial fjords.

  16. Intersection model for estimating sea otter mortality from the Exxon Valdez oil spill along the Kenai Peninsula, Alaska. Marine mammal study 6-5. Exxon Valdez oil spill state/federal natural resource damage assessment final report

    SciTech Connect

    Bodkin, J.L.; Udevitz, M.S.

    1995-06-01

    The authors developed an analytical model (intersection model) to estimate the exposure of sea otters (Enhydra lutris), to oil from the Exxon Valdez oil spill. The authors applied estimated and assumed exposure dependent mortality rates to the Kenai Peninsula sea otter population to provide examples of the application of the model in estimating sea otter mortality. The intersection model requires three distinct types of data: (1) distribution, abundance, and movements of oil, (2) abundance and distribution of sea otters, and (3) sea otter mortality rates relative to oil exposure. Initial output of the model is an estimate of exposure of otters to oil. Exposure is measured in amount and duration of oil near an otter`s observed location (intersections). The authors provide two examples of the model using different assumptions about the relation between exposure and mortality. Because of an apparent non-linear relation between the degree of oiling and survival of otters from rehabilitation, output from the authors` examples are likely biased.

  17. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Though it's not quite spring, waters in the Gulf of Alaska (right) appear to be blooming with plant life in this true-color MODIS image from March 4, 2002. East of the Alaska Peninsula (bottom center), blue-green swirls surround Kodiak Island. These colors are the result of light reflecting off chlorophyll and other pigments in tiny marine plants called phytoplankton. The bloom extends southward and clear dividing line can be seen west to east, where the bloom disappears over the deeper waters of the Aleutian Trench. North in Cook Inlet, large amounts of red clay sediment are turning the water brown. To the east, more colorful swirls stretch out from Prince William Sound, and may be a mixture of clay sediment from the Copper River and phytoplankton. Arcing across the top left of the image, the snow-covered Brooks Range towers over Alaska's North Slope. Frozen rivers trace white ribbons across the winter landscape. The mighty Yukon River traverses the entire state, beginning at the right edge of the image (a little way down from the top) running all the way over to the Bering Sea, still locked in ice. In the high-resolution image, the circular, snow-filled calderas of two volcanoes are apparent along the Alaska Peninsula. In Bristol Bay (to the west of the Peninsula) and in a couple of the semi-clear areas in the Bering Sea, it appears that there may be an ice algae bloom along the sharp ice edge (see high resolution image for better details). Ground-based observations from the area have revealed that an under-ice bloom often starts as early as February in this region and then seeds the more typical spring bloom later in the season.

  18. Geologic map of the Cook Inlet region, Alaska, including parts of the Talkeetna, Talkeetna Mountains, Tyonek, Anchorage, Lake Clark, Kenai, Seward, Iliamna, Seldovia, Mount Katmai, and Afognak 1:250,000-scale quadrangles

    USGS Publications Warehouse

    Wilson, Frederic H.; Hults, Chad P.; Schmoll, Henry R.; Haeussler, Peter J.; Schmidt, Jeanine M.; Yehle, Lynn A.; Labay, Keith A.

    2012-01-01

    In 1976, L.B. Magoon, W.L. Adkinson, and R.M. Egbert published a major geologic map of the Cook Inlet region, which has served well as a compilation of existing information and a guide for future research and mapping. The map in this report updates Magoon and others (1976) and incorporates new and additional mapping and interpretation. This map is also a revision of areas of overlap with the geologic map completed for central Alaska (Wilson and others, 1998). Text from that compilation remains appropriate and is summarized here; many compromises have been made in strongly held beliefs to allow construction of this compilation. Yet our willingness to make interpretations and compromises does not allow resolution of all mapping conflicts. Nonetheless, we hope that geologists who have mapped in this region will recognize that, in incorporating their work, our regional correlations may have required some generalization or lumping of map units. Many sources were used to produce this geologic map and, in most cases, data from available maps were combined, without generalization, and new data were added where available. A preliminary version of this map was published as U.S. Geological Survey Open-File Report 2009–1108. The main differences between the versions concern revised mapping of surfical deposits in the northern and eastern parts of the map area. Minor error corrections have been made also.

  19. Biospheric and petrogenic organic carbon flux along southeast Alaska

    NASA Astrophysics Data System (ADS)

    Cui, Xingqian; Bianchi, Thomas S.; Jaeger, John M.; Smith, Richard W.

    2016-10-01

    Holocene fjords store ca. 11-12% of the total organic carbon (OC) buried in marine sediments with fjords along southeast (SE) Alaska possibly storing half of this OC (Smith et al., 2015). However, the respective burial of biospheric (OCbio) and petrogenic OC (OCpetro) remains poorly constrained, particularly across glaciated versus non-glaciated systems. Here, we use surface sediment samples to quantify the sources and burial of sedimentary OC along SE Alaska fjord-coastal systems, and conduct a latitudinal comparison across a suite of fjords and river-coastal systems with distinctive OC sources. Our results for SE Alaska show that surface sediments in northern fjords (north of Icy Strait) with headwater glaciers are dominated by OCpetro, in contrast to marine and terrestrially-derived fresh OC in non-glaciated southern fjords. Along the continental shelf of the Gulf of Alaska, terrestrial OC is exported from rivers. Using end-member mixing models, we determine that glaciated fjords have significantly higher burial rates of OCpetro (∼ 1.1 ×103 gOC m-2yr-1) than non-glaciated fjords and other coastal systems, making SE Alaska potentially the largest sink of OCpetro in North America. In contrast, non-glaciated fjords in SE Alaska are effective in burying marine OC (OCbio-mari) (13-82 g OC m-2yr-1). Globally, OC in fjord sediments are comprised of a mixture of OCpetro and fresh OCbio, in contrast to the pre-aged OC from floodplain river-coastal systems. We find that there may be a general latitudinal trend in the role of fjords in processing OC, where high-latitude temperate glacial fjords (e.g., Yakutat Bay, SE Alaska) rebury OCpetro and non-glacial mid-latitude fjords (e.g., Doubtful Sound, Fiordland) sequester CO2 from phytoplankton and/or temperate forests. Overall, we propose that fjords are effective in sequestering OCbio and re-burying OCpetro. Based on our study, we hypothesize that climate change will have a semi-predictable impact on fjords' OC cycling in

  20. Hydrologic Modeling in the Kenai River Watershed using Event Based Calibration

    NASA Astrophysics Data System (ADS)

    Wells, B.; Toniolo, H. A.; Stuefer, S. L.

    2015-12-01

    Understanding hydrologic changes is key for preparing for possible future scenarios. On the Kenai Peninsula in Alaska the yearly salmon runs provide a valuable stimulus to the economy. It is the focus of a large commercial fishing fleet, but also a prime tourist attraction. Modeling of anadromous waters provides a tool that assists in the prediction of future salmon run size. Beaver Creek, in Kenai, Alaska, is a lowlands stream that has been modeled using the Army Corps of Engineers event based modeling package HEC-HMS. With the use of historic precipitation and discharge data, the model was calibrated to observed discharge values. The hydrologic parameters were measured in the field or calculated, while soil parameters were estimated and adjusted during the calibration. With the calibrated parameter for HEC-HMS, discharge estimates can be used by other researches studying the area and help guide communities and officials to make better-educated decisions regarding the changing hydrology in the area and the tied economic drivers.

  1. Preliminary Geologic Map of the Cook Inlet Region, Alaska-Including Parts of the Talkeetna, Talkeetna Mountains, Tyonek, Anchorage, Lake Clark, Kenai, Seward, Iliamna, Seldovia, Mount Katmai, and Afognak 1:250,000-scale Quadrangles

    USGS Publications Warehouse

    Geologic map compiled by Wilson, Frederic H.; Hults, Chad P.; Schmoll, Henry R.; Haeussler, Peter J.; Schmidt, Jeanine M.; Yehle, Lynn A.; Digital files prepared by Wilson, Frederic H.; Labay, Keith A.; Shew, Nora

    2009-01-01

    The growth in the use of Geographic Information Systems (GIS) has highlighted the need for digital geologic maps that have been attributed with information about age and lithology. Such maps can be conveniently used to generate derivative maps for manifold special purposes such as mineral-resource assessment, metallogenic studies, tectonic studies, and environmental research. This report is part of a series of integrated geologic map databases that cover the entire United States. Three national-scale geologic maps that portray most or all of the United States already exist; for the conterminous U.S., King and Beikman (1974a,b) compiled a map at a scale of 1:2,500,000, Beikman (1980) compiled a map for Alaska at 1:2,500,000 scale, and for the entire U.S., Reed and others (2005a,b) compiled a map at a scale of 1:5,000,000. A digital version of the King and Beikman map was published by Schruben and others (1994). Reed and Bush (2004) produced a digital version of the Reed and others (2005a) map for the conterminous U.S. The present series of maps is intended to provide the next step in increased detail. State geologic maps that range in scale from 1:100,000 to 1:1,000,000 are available for most of the country, and digital versions of these state maps are the basis of this product. The digital geologic maps presented here are in a standardized format as ARC/INFO export files and as ArcView shape files. The files named __geol contain geologic polygons and line (contact) attributes; files named __fold contain fold axes; files named __lin contain lineaments; and files named __dike contain dikes as lines. Data tables that relate the map units to detailed lithologic and age information accompany these GIS files. The map is delivered as a set 1:250,000-scale quadrangle files. To the best of our ability, these quadrangle files are edge-matched with respect to geology. When the maps are merged, the combined attribute tables can be used directly with the merged maps to make

  2. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area (egda) § 13.1328 EGDA closures and restrictions. The Superintendent may prohibit...

  3. 36 CFR 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General... trail near Exit Glacier to the emergency hut near the terminus is closed to— (a) Camping within 1/8...

  4. 36 CFR 13.1316 - Commercial transport of passengers by motor vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords... transport of passengers by motor vehicles on Exit Glacier Road is allowed without a written permit. However... prohibited. Exit Glacier Developed Area (EGDA)...

  5. 36 CFR 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General... trail near Exit Glacier to the emergency hut near the terminus is closed to— (a) Camping within 1/8...

  6. 36 CFR 13.1316 - Commercial transport of passengers by motor vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords... transport of passengers by motor vehicles on Exit Glacier Road is allowed without a written permit. However... prohibited. Exit Glacier Developed Area (EGDA)...

  7. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area (egda) § 13.1328 EGDA closures and restrictions. The Superintendent may prohibit...

  8. 36 CFR 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General... trail near Exit Glacier to the emergency hut near the terminus is closed to— (a) Camping within 1/8...

  9. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area (egda) § 13.1328 EGDA closures and restrictions. The Superintendent may prohibit...

  10. 36 CFR 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General... trail near Exit Glacier to the emergency hut near the terminus is closed to— (a) Camping within 1/8...

  11. 36 CFR 13.1316 - Commercial transport of passengers by motor vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords... transport of passengers by motor vehicles on Exit Glacier Road is allowed without a written permit. However... prohibited. Exit Glacier Developed Area (EGDA)...

  12. 36 CFR 13.1316 - Commercial transport of passengers by motor vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords... transport of passengers by motor vehicles on Exit Glacier Road is allowed without a written permit. However... prohibited. Exit Glacier Developed Area (EGDA)...

  13. 36 CFR 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General... trail near Exit Glacier to the emergency hut near the terminus is closed to— (a) Camping within 1/8...

  14. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area (egda) § 13.1328 EGDA closures and restrictions. The Superintendent may prohibit...

  15. 36 CFR 13.1316 - Commercial transport of passengers by motor vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords... transport of passengers by motor vehicles on Exit Glacier Road is allowed without a written permit. However... prohibited. Exit Glacier Developed Area (EGDA)...

  16. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area (egda) § 13.1328 EGDA closures and restrictions. The Superintendent may prohibit...

  17. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area (egda) § 13.1322 Food storage. Cooking, consuming, storing or preparing food in the Exit...

  18. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit...

  19. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area (egda) § 13.1322 Food storage. Cooking, consuming, storing or preparing food in the Exit...

  20. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit...

  1. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit...

  2. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit...

  3. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...) On Exit Glacier Road; (b) In parking areas; (c) On a designated route through the Exit...

  4. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed Area (egda) § 13.1322 Food storage. Cooking, consuming, storing or preparing food in the Exit...

  5. Earthshots: Satellite images of environmental change – Hubbard Glacier, Alaska, USA

    USGS Publications Warehouse

    Adamson, Thomas

    2015-01-01

    These Landsat images illustrate an unusual event that was observed twice at the terminus of Hubbard Glacier. Hubbard temporarily blocked Russell Fjord (a long, narrow inlet of the sea) from the rest of Disenchantment Bay and the Gulf of Alaska. It’s even possible that the glacier could one day permanently block the fjord.

  6. Kahtnuht'ana Qenaga (The Kenai People's Language).

    ERIC Educational Resources Information Center

    Kalifornsky, Peter

    This collection of writings in and about the Kenai language is intended for students at the intermediate or advanced level. The volume is divided into five sections: (1) narratives about Dena'ina life; (2) traditional stories or "sukdu"; (3) prayers and songs; (4) literacy and grammar exercises; and (5) place names. The narratives, stories,…

  7. Water renewals in the Saguenay Fjord

    NASA Astrophysics Data System (ADS)

    Belzile, Mélany; Galbraith, Peter S.; Bourgault, Daniel

    2016-01-01

    Water renewals and renewal times of the Saguenay Fjord are investigated and classified according to their intrusion depth. Renewal dynamics are controlled by a shallow sill (˜20 m) at the fjord mouth, by large tides that are a distinguishing feature of the Saguenay Fjord and by large vertical mixing inside the inner basin (). A mooring was deployed in the inner basin of the fjord to provide a clearer quantitative understanding of the complexity and seasonality of water renewals in this seasonally ice-covered fjord. The mooring provided information on currents over nearly the entire water column, along with temperature-salinity at a few discrete depths. Hydrographic temperature and salinity transects spanning multiple seasons and years as well as turbulence profiles were also collected. The observations show that the fjord dynamics are more complex than previously hypothesized, with large changes in renewal event depths leading to three different renewal regimes. Part of this renewal depth variability may be explained by the seasonality of the St. Lawrence estuarine circulation. Because of the large turbulence within the inner basin bottom layer, the density decreases over time such that new deep renewals can occur every year. The mechanisms behind the large vertical mixing cannot yet be clearly identified but a statistically significant correlation () suggests that internal wave breaking may be a significant contributor to deep turbulence mixing in the inner basin. The renewal time of the inner basin waters is estimated to be between 1 and 6 months.

  8. 78 FR 34609 - Proposed Modification of Class D and E Airspace; Kenai, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... airspace, Class E surface airspace and Class E airspace designated as an extension to Class D surface area... surface area airspace excluded below 1,100 feet MSL beyond 4 miles from the airport would be decreased... Designated as Surface Areas. * * * * * ] AAL AK E2 Kenai, AK Kenai Municipal Airport, AK (Lat. 60 34'24''...

  9. 76 FR 24457 - Kenai Peninsula-Anchorage Borough Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-02

    ... agency #0;statements of organization and functions are examples of documents #0;appearing in this section...; ] DEPARTMENT OF AGRICULTURE Forest Service Kenai Peninsula--Anchorage Borough Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Kenai Peninsula--Anchorage...

  10. 78 FR 65208 - Modification of Class D and E Airspace; Kenai, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ... modify controlled airspace at Kenai Municipal Airport, Kenai, AK (78 FR 34609). Interested parties were... extending to 10.2 miles northeast of the airport is adjusted to coincide with the dimensions of the cutout... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3)...

  11. Columbia Bay, Alaska: an 'upside down' estuary

    USGS Publications Warehouse

    Walters, R.A.; Josberger, E.G.; Driedger, C.L.

    1988-01-01

    Circulation and water properties within Columbia Bay, Alaska, are dominated by the effects of Columbia Glacier at the head of the Bay. The basin between the glacier terminus and the terminal moraine (sill depth of about 22 m) responds as an 'upside down' estuary with the subglacial discharge of freshwater entering at the bottom of the basin. The intense vertical mixing caused by the bouyant plume of freshwater creates a homogeneous water mass that exchanges with the far-field water through either a two- or a three-layer flow. In general, the glacier acts as a large heat sink and creates a water mass which is cooler than that in fjords without tidewater glaciers. The predicted retreat of Columbia Glacier would create a 40 km long fjord that has characteristics in common with other fjords in Prince William Sound. ?? 1988.

  12. Population genetic structure of moose (Alces Alces) of South-central Alaska.

    USGS Publications Warehouse

    Wilson, Robert E.; McDonough, John T.; Barboza, Perry S.; Talbot, Sandra L.; Farley, Sean D.

    2015-01-01

    The location of a population can influence its genetic structure and diversity by impacting the degree of isolation and connectivity to other populations. Populations at range margins areoften thought to have less genetic variation and increased genetic structure, and a reduction in genetic diversity can have negative impacts on the health of a population. We explored the genetic diversity and connectivity between 3 peripheral populations of moose (Alces alces) with differing potential for connectivity to other areas within interior Alaska. Populations on the Kenai Peninsula and from the Anchorage region were found to be significantly differentiated (FST= 0.071, P < 0.0001) with lower levels of genetic diversity observed within the Kenai population. Bayesian analyses employing assignment methodologies uncovered little evidence of contemporary gene flow between Anchorage and Kenai, suggesting regional isolation. Although gene flow outside the peninsula is restricted, high levels of gene flow were detected within the Kenai that is explained by male-biased dispersal. Furthermore, gene flow estimates differed across time scales on the Kenai Peninsula which may have been influenced by demographic fluctuations correlated, at least in part, with habitat change.

  13. Fjords in viscous fingering: selection of width and opening scale

    SciTech Connect

    Mineev-weinstein, Mark; Ristroph, Leif; Thrasher, Matthew; Swinney, Harry

    2008-01-01

    Our experiments on viscous fingering of air into oil contained between closely spaced plates reveal two selection rules for the fjords of oil that separate fingers of air. (Fjords are the building blocks of solutions of the zero-surface-tension Laplacian growth equation.) Experiments in rectangular and circular geometries yield fjords with base widths {lambda}{sub c}/2, where {lambda}{sub c} is the most unstable wavelength from a linear stability analysis. Further, fjords open at an angle of 8.0{sup o}{+-}1.0{sup o}. These selection rules hold for a wide range of pumping rates and fjord lengths, widths, and directions.

  14. Organic geochemistry of Baffin Island fjords

    SciTech Connect

    Macko, S.A.; Ivany, D.E.; Pulchan, K.

    1985-01-01

    Fjords are natural laboratories which approximate deepwater ocean systems wherein the input, recycling and preservation of organic matter can be better understood. Seven fjords, representing a cross-section of characteristics with respect to hydrography, inputs and morphology have been utilized in this study to quantify and distinguish the sources and fate of organic matter. Low level organic terrigenous inputs derived from arctic tundra vegetation are readily resolved from more organic rich marine sources through stable isotopic and bound amino acid compositions of sedimentary organic matter. Increasing enrichments in amino acid content (8 ..mu..mol/g to 26 ..mu..mol/g) as well as /sup 15/N and /sup 13/C stable isotopic abundances (+4 per thousands to +10 per thousands and -25 per thousands to -21.5 per thousands, respectively) are observed seaward of fjord heads. As a result of increased kinetic isotopic fractionation attributed to temperature effects, two separate marine organic sources, macrophytic algae and saltmarsh plants, can be distinguished from the normal marine planktonic end member. The fjord sediments are more enriched in /sup 15/N than Mid-Atlantic Coast shelf sediments. This difference may reflect extensive fertilizer input to the ocean along the Mid-Atlantic Seaboard. Relative amino acid abundances also appear to be useful for identifying sources of organic matter preserved in these sediments.

  15. Modeling glacial meltwater plume dynamics and sedimentation in high-latitude fjords

    NASA Astrophysics Data System (ADS)

    Mugford, R. I.; Dowdeswell, J. A.

    2011-03-01

    A model, SedPlume, has been developed to simulate marine sediment deposited by glacial meltwater plumes emerging from tidewater glaciers. Turbid meltwater emerging from beneath a glacier into a fjord rises as a buoyant forced plume due to density contrasts with the ambient fjord water. SedPlume assumes that meltwater discharge flows at a constant rate for long enough periods that the plume reaches a steady state. Entrainment of ambient fluid into the turbulent plume is assumed to occur at a rate proportional to the local velocity of the plume. Plume motion is considered in two dimensions: one horizontal dimension (perpendicular to the glacier front) and the vertical dimension. An integral model is formulated for the conservation equations of volume, momentum, buoyancy, and sediment flux along the path of a turbulent plume injected into stably stratified ambient fluid. Sedimentation occurs from the plume when the radial component of the sediment fall velocity exceeds the entrainment velocity. When the plume reaches the surface, it is treated as a radially spreading surface gravity current, for which exact solutions exist for the sediment deposition rate. Flocculation of silt and clay particles is modeled using empirical measurements of particle settling velocities in fjords to adjust the settling velocity of fine-grained sediments. SedPlume has been applied to McBride Inlet, Alaska, a temperate glaciated fjord where the majority of sedimentation originates from meltwater sources. SedPlume produces rates and patterns of sedimentation in good agreement with observations, with calculated peak ice-proximal annual sedimentation rates of approximately 22 m yr-1.

  16. Assessing net community production in a glaciated Alaskan fjord

    NASA Astrophysics Data System (ADS)

    Reisdorph, S. C.; Mathis, J. T.

    2015-09-01

    The impact of deglaciation in Glacier Bay has been observed to seasonally influence the biogeochemistry of this marine system. The influence from surrounding glaciers, particularly tidewater glaciers, has the potential to affect the efficiency and structure of the marine food web within Glacier Bay. To assess the magnitude and the spatial and temporal variability in net community production in a glaciated fjord, we measured dissolved inorganic carbon, inorganic macronutrients, dissolved oxygen, and particulate organic carbon between July 2011 and July 2012 in Glacier Bay, Alaska. High net community production rates were observed across the bay (~ 54 to ~ 81 mmol C m-2 d-1) between the summer and fall of 2011. However, between the fall and winter, as well as between the winter and spring of 2012, air-sea fluxes of carbon dioxide and organic matter respiration made net community production rates negative across most of the bay as inorganic carbon and macronutrient concentrations returned to pre-bloom levels. The highest organic carbon production occurred within the west arm between the summer and fall of 2011 with ~ 4.5 × 105 kg C d-1. Bay-wide, there was carbon production of ~ 9.2 × 105 g C d-1 between the summer and fall. Respiration and air-sea gas exchange were the dominant drivers of carbon chemistry between the fall and winter of 2012. The substantial spatial and temporal variability in our net community production estimates may reflect glacial influences within the bay, as meltwater is depleted in macronutrients relative to marine waters entering from the Gulf of Alaska in the middle and lower parts of the bay. Further glacial retreat will likely lead to additional modifications in the carbon biogeochemistry of Glacier Bay, with unknown consequences for the local marine food web, which includes many species of marine mammals.

  17. Climate science informs participatory scenario development and applications to decision making in Alaska

    NASA Astrophysics Data System (ADS)

    Welling, L. A.; Winfree, R.; Mow, J.

    2012-12-01

    climate and social drivers of change to ecological processes and decision making. Components included review and synthesis of climate observations and projections, effects and impacts, and information on other relevant factors (e.g., subsistence activities, land cover, fire activity, land use change, sea level shifts). Although workshops focused primarily on park lands and waters, nearby communities and other land management units also participated. Results include a framework through which managers are beginning to analyze uncertainties associated with climate change and ecosystem responses and evaluate appropriate and effective actions. For example, at Kenai Fjords National Park, melting from the Harding Icefield and Exit Glacier is changing how managers respond to local flooding issues. The Exit Glacier is one of the park's iconic visitor experiences and in the last four years, the road to the glacier has been subject to mid-summer/fair weather flooding which are outside the historic norms. Rather than seek a traditional solution to the issue, park management has been working with highway engineers to evolve interim solutions as this dynamic system continues to rapidly change. Climate change scenarios established a set of possible plausible futures for the park and are also being used to "wind tunnel" potential responses.

  18. Seasonal hydrography and surface outflow in a fjord with deep sill: the Reloncavi fjord, Chile

    NASA Astrophysics Data System (ADS)

    Castillo, M. I.; Cifuentes, U.; Pizarro, O.; Djurfeldt, L.; Caceres, M.

    2015-10-01

    Seasonal information of temperature, salinity, dissolved oxygen (DO) and chlorophyll, combined with meteorological and river discharge time series were used to describe the oceanographic conditions in the Reloncavi fjord (41°35' S; 72°20' W). The winds in the fjord valley blow mainly down-fjord during winter, reinforcing the upper layer outflow, while in spring-summer winds have a predominant up-fjord direction contrary to upper layer outflow. The fjord, with a deep sill at the mouth, was well stratified year-round and showed a thin surface layer of brackish water with mean salinities between 10.4 ± 1.4 (spring) and 13.2 ± 2.5 (autumn). The depth of the upper layer changed slightly along the different studied seasons remaining at about 4.5 m near the mouth. This upper layer presented a mean outflow (Q1) of 3185 ± 223 m3 s-1, which imply a flushing time of about 3 days of this layer. The vertical salt flux was ∼ 37 tons of salt per second, similar to the horizontal salt flux observed in the upper layer. These estimations will contribute to a better management of the aquaculture on this region.

  19. Spatio-temporal Variation in Glacier Ice as Habitat for Harbor Seals in an Alaskan Tidewater Glacier Fjord

    NASA Astrophysics Data System (ADS)

    Womble, J. N.; McNabb, R. W.; Gens, R.; Prakash, A.

    2015-12-01

    Some of the largest aggregations of harbor seals (Phoca vitulina richardii) in Alaska occur in tidewater glacier fjords where seals rest upon icebergs that are calved from tidewater glaciers into the marine environment. The distribution, amount, and size of floating ice in fjords are likely important factors influencing the spatial distribution and abundance of harbor seals; however, fine-scale characteristics of ice habitat that are used by seals have not been quantified using automated methods. We quantified the seasonal changes in ice habitat for harbor seals in Johns Hopkins Inlet, a tidewater glacier fjord in Glacier Bay National Park, Alaska, using aerial photography, object-based image analysis, and spatial models. Aerial photographic surveys (n = 53) were conducted of seals and ice during the whelping (June) and molting (August) seasons from 2007-2014. Surveys were flown along a grid of 12 transects and high-resolution digital photos were taken directly under the plane using a vertically aimed camera. Seal abundance and spatial distribution was consistently higher during June (range: 1,672-4,340) than August (range: 1,075-2,582) and corresponded to the spatial distribution and amount of ice. Preliminary analyses from 2007 suggest that the average percent of icebergs (ice ≥ than 1.6m2) and brash ice (ice < 1.6m2) per scene were greater in June (icebergs: 1.8% ± 1.6%; brash ice: 43.8% ± 38.9%) than August (icebergs: 0.2% ± 0.7%; brash ice; 15.8% ± 26.4%). Iceberg angularity (an index of iceberg shape) was also greater in June (1.7 ± 0.9) than August (0.9 ± 0.9). Potential factors that may influence the spatio-temporal variation in ice habitat for harbor seals in tidewater glacier fjords include frontal ablation rates of glaciers, fjord circulation, and local winds. Harbor seals exhibit high seasonal fidelity to tidewater glacier fjords, thus understanding the relationships between glacier dynamics and harbor seal distribution will be critical for

  20. High rates of organic carbon burial in fjord sediments globally

    NASA Astrophysics Data System (ADS)

    Smith, Richard W.; Bianchi, Thomas S.; Allison, Mead; Savage, Candida; Galy, Valier

    2015-06-01

    The deposition and long-term burial of organic carbon in marine sediments has played a key role in controlling atmospheric O2 and CO2 concentrations over the past 500 million years. Marine carbon burial represents the dominant natural mechanism of long-term organic carbon sequestration. Fjords--deep, glacially carved estuaries at high latitudes--have been hypothesized to be hotspots of organic carbon burial, because they receive high rates of organic material fluxes from the watershed. Here we compile organic carbon concentrations from 573 fjord surface sediment samples and 124 sediment cores from nearly all fjord systems globally. We use sediment organic carbon content and sediment delivery rates to calculate rates of organic carbon burial in fjord systems across the globe. We estimate that about 18 Mt of organic carbon are buried in fjord sediments each year, equivalent to 11% of annual marine carbon burial globally. Per unit area, fjord organic carbon burial rates are one hundred times as large as the global ocean average, and fjord sediments contain twice as much organic carbon as biogenous sediments underlying the upwelling regions of the ocean. We conclude that fjords may play an important role in climate regulation on glacial-interglacial timescales.

  1. Varieties of submarine failure morphologies of seismically-induced landslides in Alaskan fjords

    USGS Publications Warehouse

    Lee, H.; Ryan, H.; Kayen, R.E.; Haeussler, P.J.; Dartnell, P.; Hampton, M.A.

    2006-01-01

    The Great Alaska Earthquake of 1964 caused major damage and 43 deaths in the coastal communities of Seward and Valdez. Most of these losses were caused by tsunamis that occurred immediately after the earthquake and were most likely induced by local submarine landslides. Recent NOAA multibcam bathymetric surveys near Seward and Valdez provide detailed information about the morphology of landslide deposits in both areas. High-resolution (chirp) surveys were conducted by the USGS, and sediment samples were taken over apparent landslide debris. Landslide deposits near Seward typically take the form of a series of large and small blocks lying directly off the front of the town, although there are indications of sandy and muddy debris flows occurring off river deltas. Near Valdez, landslide morphologies include at least three forms: a field of large blocks (up to 40 m high), an intricate series of gullies, channels, and talus near the fjord-head delta and a broad debris lobe that apparently flowed half-way down the fjord and stopped. The 1964 landslide tsunamis may have been composites resulting from a number of landslide events.

  2. Carbon cycling and burial in New Zealand's fjords

    NASA Astrophysics Data System (ADS)

    Hinojosa, Jessica L.; Moy, Christopher M.; Stirling, Claudine H.; Wilson, Gary S.; Eglinton, Timothy I.

    2014-10-01

    carbon cycling in continental margin settings is critical for constraining the global carbon cycle. Here we apply a multiproxy geochemical approach to evaluate regional carbon cycle dynamics in six New Zealand fjords. Using carbon and nitrogen concentrations and isotopes, lipid biomarkers, and redox-sensitive element concentrations, we show that the New Zealand fjords have carbon-rich surface sediments in basins that promote long-term storage (i.e., semirestricted basins with sediment accumulation rates of up to 4 mm yr-1). Using δ13C distributions to develop a mixing model, we find that organic carbon in fjord sediments is well-mixed from marine and terrestrial sources in down-fjord gradients. This is driven by high regional precipitation rates of >6 m yr-1, which promote carbon accumulation in fjord basins through terrestrial runoff. In addition, we have identified at least two euxinic subbasins, based on uranium, molybdenum, iron, and cadmium enrichment, that contain >7% organic carbon. Because the strength and position of the Southern Hemisphere westerly winds control precipitation and fjord circulation, carbon delivery and storage in the region are intimately linked to westerly wind variability. We estimate that the fjord region (759 km2) may be exporting up to 1.4 × 107 kgC yr-1, outpacing other types of continental margins in rates of carbon burial by up to 3 orders of magnitude.

  3. Seasonal changes in Fe along a glaciated Greenlandic fjord.

    NASA Astrophysics Data System (ADS)

    Hopwood, Mark; Connelly, Douglas; Arendt, Kristine; Juul-Pedersen, Thomas; Stinchcombe, Mark; Meire, Lorenz; Esposito, Mario; Krishna, Ram

    2016-03-01

    Greenland's ice sheet is the second largest on Earth, and is under threat from a warming Arctic climate. An increase in freshwater discharge from Greenland has the potential to strongly influence the composition of adjacent water masses with the largest impact on marine ecosystems likely to be found within the glaciated fjords. Here we demonstrate that physical and chemical estuarine processes within a large Greenlandic fjord are critical factors in determining the fate of meltwater derived nutrients and particles, especially for non-conservative elements such as Fe. Concentrations of Fe and macronutrients in surface waters along Godthåbsfjord, a southwest Greenlandic fjord with freshwater input from 6 glaciers, changed markedly between the onset and peak of the meltwater season due to the development of a thin (<10 m), outflowing, low-salinity surface layer. Dissolved (<0.2 µm) Fe concentrations in meltwater entering Godthåbsfjord (200 nM), in freshly melted glacial ice (mean 38 nM) and in surface waters close to a land terminating glacial system (80 nM) all indicated high Fe inputs into the fjord in summer. Total dissolvable (unfiltered at pH <2.0) Fe was similarly high with concentrations always in excess of 100 nM throughout the fjord and reaching up to 5.0 µM close to glacial outflows in summer. Yet, despite the large seasonal freshwater influx into the fjord, Fe concentrations near the fjord mouth in the out-flowing surface layer were similar in summer to those measured before the meltwater season. Furthermore, turbidity profiles indicated that sub-glacial particulate Fe inputs may not actually mix into the outflowing surface layer of this fjord. Emphasis has previously been placed on the possibility of increased Fe export from Greenland as meltwater fluxes increase. Here we suggest that in-fjord processes may be effective at removing Fe from surface waters before it can be exported to coastal seas.

  4. 210-Pb Study of Fjord Sedimentation Rates in the South Shetland Islands and Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Kimball, B. L.; Nittrouer, C. A.; Landowski, C. M.; Koppes, M.; Hallet, B.

    2007-12-01

    As part of a study concerning the factors controlling rates of glacial erosion and sedimentation across climatic regimes, sixteen kasten cores were collected from ten fjords in the South Shetland Islands and Antarctic Peninsula in April and May, 2007 from the R/VIB Nathaniel B. Palmer. They were sampled for 210Pb measurements of accumulation rates and associated sedimentological observations (x-radiography, sedimentology). The cores were collected from basins within a few kilometers of the calving front at the respective glacier, where sediment accumulation was observed in 3.5 kHz sub-bottom profiles. Core lengths ranged from 34-289 cm; in 7 of the 16 core locations, multiple deployments were required to retrieve even a short sediment core due to the hardness of the bed. For most of the cores (10 of 16) sandy mud has accumulated steadily at rates ranging from 1 to 10 mm/y over the past century, as tightly defined by clear linear trends of 10 to 15 log 210Pb values versus depth, with r2 ranging from 0.75-0.98. The rates of accumulation appear to be independent of distance from the calving front, and most likely reflect variability in glacial-marine sediment delivery to, and basin morphology of, individual fjords. Several cores show evidence of variable sedimentation with pulses of sand emplacement. Three cores contained a surficial layer >50 cm thick of uniform 210Pb activity, indicating recent, rapid deposition of a large turbidity current or mass flow. The consistency of many of the 210Pb profiles implies that, over the past century, the glacial-marine processes that supplied, transported and deposited sediment in these sub-polar and polar fjords have not varied markedly. This contrasts with other glacial-marine systems in warmer regions such SE Alaska, where sedimentation in the fjords from calving temperate glaciers tends to vary significantly, and where the accumulation tends to slow as the calving front recedes rapidly from the core location. The rates of

  5. A Bayesian Hierarchical Model for Spatio-Temporal Prediction and Uncertainty Assessment Using Repeat LiDAR Acquisitions for the Kenai Peninsula, AK, USA

    NASA Astrophysics Data System (ADS)

    Babcock, C. R.; Andersen, H. E.; Finley, A. O.; Cook, B.; Morton, D. C.

    2015-12-01

    Models using repeat LiDAR and field campaigns may be one mechanism to monitor carbon storage and flux in forested regions. Considering the ability of multi-temporal LiDAR to estimate growth, it is not surprising that there is great interest in developing forest carbon monitoring strategies that rely on repeated LiDAR acquisitions. Allowing for sparser field campaigns, LiDAR stands to make monitoring forest carbon cheaper and more efficient than field-only sampling procedures. Here, we look to the spatio-temporally data-rich Kenai Peninsula in Alaska to examine the potential for Bayesian spatio-temporal mapping of forest carbon storage and uncertainty. The framework explored here can predict forest carbon through space and time, while formally propagating uncertainty through to prediction. Bayesian spatio-temporal models are flexible frameworks allowing for forest growth processes to be formally integrated into the model. By incorporating a mechanism for growth---using temporally repeated field and LiDAR data---we can more fully exploit the information-rich inventory network to improve prediction accuracy. LiDAR data for the Kenai Peninsula has been collected on four different occasions---spatially coincident LiDAR strip samples in 2004, 09 and 14, along with a wall-to-wall collection in 2008. There were 436 plots measured twice between 2002 and 2014. LiDAR was acquired at least once over most inventory plots with many having LiDAR collected during 2, 3 or 4 different campaigns. Results from this research will impact how forests are inventoried. It is too expensive to monitor terrestrial carbon using field-only sampling strategies and currently proposed LiDAR model-based techniques lack the ability to properly utilize temporally repeated and misaligned data. Bayesian hierarchical spatio-temporal models offer a solution to these shortcomings and allow for formal predictive error assessment, which is useful for policy development and decision making.

  6. Glacial Geomorphic Characteristics of the Antarctic Peninsula Fjords

    NASA Astrophysics Data System (ADS)

    Wellner, J. S.; Munoz, Y. P.; Mead, K. A.; Hardin, L. A.

    2011-12-01

    A distinctive suite of subglacial geomorphic features, representing the grounding of an ice sheet and its subsequent retreat, has been well documented for many parts of the Antarctic continental shelf. Geomorphic features include meltwater channels, drumlins, mega-scale glacial lineations, and gullies cut into the upper slope. Many of these same features occur in more recently deglaciated fjords, but at different scales and in different combinations. We have surveyed twelve fjords on the Antarctic Peninsula, from the Graham Land Coast to Hope Bay as well as on Anvers Island and in the South Shetland Islands. Surveys include multibeam swath bathymetry, CHIRP 3.5 kHz seismic, and sediment cores. Recently, we have reprocessed much of the multibeam data using new software allowing higher-resolution imagery. Unlike on the outer continental shelf of the Antarctic Peninsula, where there is a relatively simple suite of geomorphic features and a uniform retreat history, the fjords on the inner shelf show a complex geomorphic pattern representing somewhat unique glacial retreat histories for each fjord. Several fjords have distinctive grounding zone wedge deposits, and some fjords have such wedges in multiple locations, representing multiple pauses in the retreat history, or a stepped retreat of the ice. Drumlins and mega-scale glacial lineations are present in the fjords, but extend for kms rather than the tens of kms that are typical of the outer shelf. If drumlins are interpreted to indicate acceleration of grounded ice, as they are on the outer shelf, then there must have been multiple zones of acceleration across the flow path of the ice as drumlin sets occur in multiple zones in a single flow path. The inner parts of many fjords along the coast of the peninsula are characterized by features interpreted as erosional meltwater channels, although such features are not common in fjords in the islands off the peninsula, despite the similar scale of the fjords themselves

  7. Semidiurnal internal tides in a Patagonian fjord

    NASA Astrophysics Data System (ADS)

    Ross, L.; Pérez-Santos, I.; Valle-Levinson, A.; Schneider, W.

    2014-12-01

    The fjords of central Chilean Patagonia (47°S) receive fresh water from both precipitation and the Baker River. This buoyancy input generates a two layer hydrographic system characterized by strong salinity stratification (∼30 g kg-1 over a depth range of 7-15 m), which favors baroclinic conditions in the fjord. Hourly current velocity profiles were collected with an acoustic Doppler current profiler (ADCP) moored at a depth of 40 m during March-April 2009, and complemented by 11 CTD profiles and hourly sea level time series. These data allowed the detection of semidiurnal internal tidal waves for the first time in this region. Wavelength and horizontal phase speeds were determined by the dynamical mode 1 for internal waves. Maximum wavelength was 52 km, travelling at a horizontal phase speed of ∼1.16 m s-1. Wavelet, spectral and empirical orthogonal function (EOF) analysis techniques applied to the echo anomaly signal and to the baroclinic velocity showed largest semidiurnal amplitudes near the pycnocline. Out of three modes obtained from the EOF analysis, two modes displayed a two- or three-layer flow structure with flow direction reversing at the pycnocline. The semidiurnal internal waves were found as fluctuations near the pycnocline in sporadic packets correlated to high discharge pulses of the Baker River (r2 = 0.77). Additionally, internal Froude number calculations at the mouth of the Baker River indicated critical flow conditions, which allowed for generation of internal waves at the plume front. These waves are separated from the river plume after internal wave phase speeds surpassed frontal speeds. This suggests that the internal waves were modulated by pulses in high river discharge rather than the interaction of barotropic tide with bathymetry (a sill). An implication of these internal waves would be to increase vertical mixing of nutrients toward the surface, through shear instabilities, which would favor primary production.

  8. Identification of functional corridors with movement characteristics of brown bears on the Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Graves, T.A.; Farley, S.; Goldstein, M.I.; Servheen, C.

    2007-01-01

    We identified primary habitat and functional corridors across a landscape using Global Positioning System (GPS) collar locations of brown bears (Ursus arctos). After deriving density, speed, and angular deviation of movement, we classified landscape function for a group of animals with a cluster analysis. We described areas with high amounts of sinuous movement as primary habitat patches and areas with high amounts of very directional, fast movement as highly functional bear corridors. The time between bear locations and scale of analysis influenced the number and size of corridors identified. Bear locations should be collected at intervals ???6 h to correctly identify travel corridors. Our corridor identification technique will help managers move beyond the theoretical discussion of corridors and linkage zones to active management of landscape features that will preserve connectivity. ?? 2007 Springer Science+Business Media, Inc.

  9. Recent sedimentation, northeastern Port Valdez, Alaska

    NASA Astrophysics Data System (ADS)

    Palmer, Harold D.

    1981-09-01

    Sediments accumulating on the northeastern shore of Port Valdez, a fjord leading to Prince William Sound in southern Alaska, are derived from both deltaic and alluvial fan processes. The resulting thick wedge of Recent silts, sands, shells and gravels lies atop irregular ridges of local graywacke bedrock and scattered till deposits. Seismic reflection profiling augmented by soil borings indicates that rapid infilling and upbuilding has occurred at this site. Evidence of slumping suggests general instability of steep submarine slopes in an area characterized by strong earthquakes and large tidal ranges.

  10. 77 FR 29358 - Kenai National Wildlife Refuge, Soldotna, AK; Environmental Impact Statement for the Shadura...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-17

    ... intermingled with hundreds of lakes. Boreal forests are home to moose, wolves, black and brown bears, lynx... ) established the Refuge from the Kenai Moose Range and other lands and set forth the following major purposes... their natural diversity, including, but not limited to, moose, bear, mountain goats, Dall sheep,...

  11. 77 FR 75646 - Kenai National Wildlife Refuge, Soldotna, AK; Draft Environmental Impact Statement for the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-21

    ... of lakes. Boreal forests are home to moose, wolves, black and brown bears, lynx, snowshoe hares, and... (Section 303 ) established the Refuge from the Kenai Moose Range and other lands, and set forth the... populations and habitats in their natural diversity, including, but not limited to, moose, bear,...

  12. 78 FR 32270 - Kenai National Wildlife Refuge, Soldotna, AK; Environmental Impact Statement for the Shadura...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... intermingled with hundreds of lakes. Boreal forests are home to moose, wolves, black and brown bears, lynx... of 1980 (Section 303 ) established the Refuge from the Kenai Moose Range and other lands, and set... wildlife populations and habitats in their natural diversity, including, but not limited to, moose,...

  13. Fifty-Year Record of Glacier Change Reveals Shifting Climate in the Pacific Northwest and Alaska, USA

    USGS Publications Warehouse

    ,

    2009-01-01

    Fifty years of U.S. Geological Survey (USGS) research on glacier change shows recent dramatic shrinkage of glaciers in three climatic regions of the United States. These long periods of record provide clues to the climate shifts that may be driving glacier change. The USGS Benchmark Glacier Program began in 1957 as a result of research efforts during the International Geophysical Year (Meier and others, 1971). Annual data collection occurs at three glaciers that represent three climatic regions in the United States: South Cascade Glacier in the Cascade Mountains of Washington State; Wolverine Glacier on the Kenai Peninsula near Anchorage, Alaska; and Gulkana Glacier in the interior of Alaska (fig. 1).

  14. 36 CFR 242.3 - Applicability and scope.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... permit subsistence uses in Glacier Bay National Park, Kenai Fjords National Park, Katmai National Park, and that portion of Denali National Park established as Mt. McKinley National Park prior to passage of... Longitude; (3) National Petroleum Reserve in Alaska, including those waters shoreward of a line......

  15. 36 CFR 242.3 - Applicability and scope.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... permit subsistence uses in Glacier Bay National Park, Kenai Fjords National Park, Katmai National Park, and that portion of Denali National Park established as Mt. McKinley National Park prior to passage of... Longitude; (3) National Petroleum Reserve in Alaska, including those waters shoreward of a line......

  16. 36 CFR 13.1306 - Public use cabins.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Public use cabins. 13.1306 Section 13.1306 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions §...

  17. 36 CFR 13.1306 - Public use cabins.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Public use cabins. 13.1306 Section 13.1306 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions §...

  18. 36 CFR 13.1306 - Public use cabins.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Public use cabins. 13.1306 Section 13.1306 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions §...

  19. 36 CFR 13.1306 - Public use cabins.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Public use cabins. 13.1306 Section 13.1306 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions §...

  20. 36 CFR 13.1306 - Public use cabins.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Public use cabins. 13.1306 Section 13.1306 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park General Provisions §...

  1. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed... boundary to Exit Glacier Campground Entrance Road, all park areas within 350 meters (383 yards) of the centerline of the Exit Glacier Road; (2) From Exit Glacier Campground Entrance Road to the end of the...

  2. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed... boundary to Exit Glacier Campground Entrance Road, all park areas within 350 meters (383 yards) of the centerline of the Exit Glacier Road; (2) From Exit Glacier Campground Entrance Road to the end of the...

  3. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed... boundary to Exit Glacier Campground Entrance Road, all park areas within 350 meters (383 yards) of the centerline of the Exit Glacier Road; (2) From Exit Glacier Campground Entrance Road to the end of the...

  4. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed... boundary to Exit Glacier Campground Entrance Road, all park areas within 350 meters (383 yards) of the centerline of the Exit Glacier Road; (2) From Exit Glacier Campground Entrance Road to the end of the...

  5. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed... boundary to Exit Glacier Campground Entrance Road, all park areas within 350 meters (383 yards) of the centerline of the Exit Glacier Road; (2) From Exit Glacier Campground Entrance Road to the end of the...

  6. 36 CFR 13.1324 - Bicycles.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Bicycles. 13.1324 Section 13.1324 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  7. 36 CFR 13.1320 - Camping.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Camping. 13.1320 Section 13.1320 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  8. 36 CFR 13.1320 - Camping.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Camping. 13.1320 Section 13.1320 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  9. 36 CFR 13.1324 - Bicycles.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bicycles. 13.1324 Section 13.1324 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  10. 36 CFR 13.1320 - Camping.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Camping. 13.1320 Section 13.1320 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  11. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Ice fall hazard zones. 13.1304 Section 13.1304 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  12. 36 CFR 13.1320 - Camping.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Camping. 13.1320 Section 13.1320 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  13. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Ice fall hazard zones. 13.1304 Section 13.1304 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  14. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Ice fall hazard zones. 13.1304 Section 13.1304 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  15. 36 CFR 13.1324 - Bicycles.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Bicycles. 13.1324 Section 13.1324 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  16. 36 CFR 13.1324 - Bicycles.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Bicycles. 13.1324 Section 13.1324 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  17. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Ice fall hazard zones. 13.1304 Section 13.1304 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  18. 36 CFR 13.1320 - Camping.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Camping. 13.1320 Section 13.1320 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  19. 36 CFR 13.1324 - Bicycles.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Bicycles. 13.1324 Section 13.1324 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park Exit Glacier Developed...

  20. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Ice fall hazard zones. 13.1304 Section 13.1304 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  1. Multibeam Mapping of Remote Fjords in Southeast-Greenland

    NASA Astrophysics Data System (ADS)

    Weinrebe, W.; Kjaer, K. H.; Kjeldsen, K. K.; Bjork, A. A.

    2015-12-01

    The fjords of Southeast-Greenland are among the most remote areas of the Northern Hemisphere. Access to this area is hampered by a broad belt of sea ice floating along the East-Greenland coast from North to South. Consequently, the majority of those fjords have never been surveyed in detail until now. During an expedition by the Center of GeoGenetics of the University of Copenhagen in summer of 2014 we were able to map the Skjoldungen Fjord system with multibeam bathymetry. The topsail schooner ACTIV, built 1951 as a cargo ship to supply remote settlements in Greenland was chosen for the expedition. Though a vintage vessel, the ACTIV was well suited to cross the belt of sea ice and to cruise the ice covered fjords. A portable ELAC-Seabeam 1050 multibeam system was temporarily installed on the vessel. The two transducer of the system were mounted at the lower end of a 6 m long pole attached outboard at port side to the hull of the vessel. Though the installation was quite demanding without any winches or cranes, the construction was sufficiently stable and easy to manage throughout the entire cruise. Nearly the entire fjord system, leaving only a small gap of 5 km at the innermost part and small stripes close to the shorelines could be surveyed during the cruise. For the first time, a comprehensive map of Skjoldungen Fjord is now available. The map displays water depths from close to zero up to 800 m, the deepest part along a stretch of about 10 km in the Southwest. The bathymetry of the northern fjord is remarkably different from the southern fjord: the southern fjord features an outer deep part showing water depths between 500 m and 800 m and a shallow inner part with depths less than 300 m and a prominent sill in between. The northern fjord shows a more gradual increase of water depths from 200 m in the inner part to 600 m at the entrance.

  2. Holocene coastal glaciation of Alaska

    NASA Astrophysics Data System (ADS)

    Calkin, Parker E.; Wiles, Gregory C.; Barclay, David J.

    2001-01-01

    Holocene fluctuations of the three cirque glaciers on the Seward Peninsula and five groups of tidewater- and land-terminating glaciers along the northernmost Gulf of Alaska, provide a proxy record of late Holocene climatic change. Furthermore, the movements of the coastal glaciers were relevant to late Holocene native American migration. The earliest expansion was recorded about 6850 yr BP by Hubbard Glacier at the head of Yakutat Bay in the Gulf of Alaska; however, its down-fjord advance to the bay mouth was delayed until ˜2700 BP. Similarly, expansions of the Icy Bay, Bering, and McCarty glaciers occurred near their present termini by ˜3600-3000 BP, compatible with marked cooling and precipitation increases suggested by the Alaskan pollen record. Decrease in glacier activity ˜2000 BP was succeeded by advances of Gulf coastal glaciers between 1500 and 1300 BP, correlative with early Medieval expansions across the Northern Hemisphere. A Medieval Optimum, encompassing at least a few centuries prior to AD 1200 is recognized by general retreat of land-terminating glaciers, but not of all tidewater glaciers. Little Ice Age advances of land-based glaciers, many dated with the precision of tree-ring cross-dating, were centered on the middle 13th or early 15th centuries, the middle 17th and the last half of the 19th century A.D. Strong synchrony of these events across coastal Alaska is evident.

  3. Organic carbon burial in fjords: Terrestrial versus marine inputs

    NASA Astrophysics Data System (ADS)

    Cui, Xingqian; Bianchi, Thomas S.; Savage, Candida; Smith, Richard W.

    2016-10-01

    Fjords have been identified as sites of enhanced organic carbon (OC) burial and may play an important role in regulating climate change on glacial-interglacial timescales. Understanding sediment processes and sources of sedimentary OC are necessary to better constrain OC burial in fjords. In this study, we use Fiordland, New Zealand, as a case study and present data on surface sediments, sediment down-cores and terrestrial end-members to examine dynamics of sediments and the sources of OC in fjord sediments. Sediment cores showed evidence of multiple particle sources, frequent bioturbation and mass-wasting events. A multi-proxy approach (stable isotopes, lignin-phenols and fatty acids) allowed for separation of marine, soil and vascular plant OC in surface sediments. The relationship between mass accumulation rate (MAR) and OC contents in fjord surface sediments suggested that mineral dilution is important in controlling OC content on a global scale, but is less important for specific regions (e.g., New Zealand). The inconsistency of OC budgets calculated by using MAR weighted %OC and OC accumulation rates (AR; 6 vs 21-31 Tg OC yr-1) suggested that sediment flux in fjords was likely underestimated. By using end-member models, we propose that 55% to 62% of total OC buried in fjords is terrestrially derived, and accounts for 17 ± 12% of the OCterr buried in all marine sediments. The strong correlation between MAR and OC AR indicated that OC flux will likely decrease in fjords in the future with global warming due to decrease in sediment flux caused by glacier denudation.

  4. Acoustic mapping of the Ilulissat Ice Fjord mouth, West Greenland

    NASA Astrophysics Data System (ADS)

    Schumann, Kai; Völker, David; Weinrebe, Wilhelm R.

    2012-04-01

    A ship-based acoustic mapping campaign was conducted at the exit of Ilulissat Ice Fjord of West Greenland and in the sedimentary basin of Disko Bay west of the fjord mouth. Submarine landscape and sediment distribution patterns represented by five acoustic facies types represent glaciomarine sediment facies types that are related to variations in the past position and relative motion of the glacier front. Asymmetric ridges on the shelf that form a curved entity and a large sill at the fjord mouth represent moraines that depict at least two relatively stable positions of the ice front in the Disko Bay and at the fjord mouth. Comparable ice-end features are not observed seaward of the East Greenland Kangerdlugssuaq Glacier, although both glaciers are comparable in their latitudinal position, present size and present role for the ice discharge from the Inland Ice sheet. Apparently, the retreat of the Greenland Inland Ice after the last maximum expansion was a more discontinuous process on the West Greenland Shelf than on the East Greenland Shelf. The Iceberg Bank, a prominent sill at the fjord exit appears to play an important role for the sedimentation after the retreat of the ice front from the shelf was completed. The retreat of the glacier behind the Iceberg Bank into the inner fjord is marked by a reorganization of sediment delivery in Disko Bay, as most of the till is now deposited within the fjord. Two linear clusters of pockmarks in the center of the sedimentary basin seem to be linked to methane release due to dissociation of gas hydrates, a process driven by fast crustal uplift of the Greenland Shelf. The orientation of these clusters appears to reflect a migration path that is defined by a buried structure which we could not resolve.

  5. Seasonal hydrography and surface outflow in a fjord with a deep sill: the Reloncaví fjord, Chile

    NASA Astrophysics Data System (ADS)

    Castillo, Manuel I.; Cifuentes, Ursula; Pizarro, Oscar; Djurfeldt, Leif; Caceres, Mario

    2016-04-01

    Seasonal data on temperature, salinity, dissolved oxygen (DO) and chlorophyll, combined with meteorological and river discharge time series, were used to describe the oceanographic conditions of the Reloncaví fjord (41°35' S, 72°20' W). The winds in the fjord valley mainly blow down-fjord during the winter, reinforcing the upper layer outflow, whereas the winds blow predominantly up-fjord during the spring and summer, contrary to the upper layer outflow. The fjord, with a deep sill at the mouth, was well stratified year-round and featured a thin surface layer of brackish water with mean salinities between 10.4 ± 1.4 (spring) and 13.2 ± 2.5 (autumn). The depth of the upper layer changed slightly among the different studied seasons but remained at 4.5 m near the mouth. This upper layer presented a mean outflow (Q1) of 3185 ± 223 m3 s-1, which implies a flushing time of 3 days for this layer. The vertical salt flux was ˜ 37 tons of salt per second, similar to the horizontal salt flux observed in the upper layer. These estimates will contribute to better management of the aquaculture in this region.

  6. Modeling the mass balance of the Wolverine Glacier Alaska USA using the PTAA model

    NASA Astrophysics Data System (ADS)

    Korn, D.

    2010-12-01

    Glaciers in Alaska have been increasingly losing mass over the last several decades. This trend is especially apparent in South-Central Alaska where many glaciers are undergoing rapid changes and contributing substantially to rising sea levels (Arendt et al., 2002). It is important to understand the rates at which these glaciers are losing mass as well as the important climatic drivers to better prepare for what the future holds in this region and the rest of the world. This work compares glacier mass balance data modeled through the Precipitation-Temperature Area Altitude (PTAA) mass balance model for the Wolverine Glacier in the Kenai Peninsula in South-Central Alaska to observed data from the USGS “benchmark” glacier program in order to help validate the model. The mass balance data are also correlated with climate data in order to understand the main climatic drivers of the glacier mass balance in this region.

  7. Modeling of water masses exchange between Brepolen and the main fjord in the Western Svalbard fjord - Hornsund

    NASA Astrophysics Data System (ADS)

    Jakacki, Jaromir; Przyborska, Anna; Sunfjord, Arild; Albertsen, Jon; Białoskórski, Michał; Pliszka, Bartosz

    2016-04-01

    Hornsund is the southernmost fjord of the Svalbard archipelago island - Spitsbergen. It is under the influence of two main currents - the coastal Sørkapp Current (SC) carrying fresher and colder water masses from the Barents Sea and the West Spitsbergen Current (WSC), which is the branch of the Norwegian Atlantic Current (NwAC) and carries warm and salty waters from the North Atlantic. The main local forcing, which is tidal motion, brings shelf waters into the central fjord basin and then the transformed masses are carried into the easternmost part of the fjord, Brepolen. For the purpose of studying circulation and water exchange in this area a three-dimensional hydrodynamic model has been implemented and validated. The model is based on MIKE by DHI product and covers the Hornsund fjord with the shelf area, which is the fjord foreground. It is sigma a coordinate model (in our case 35 vertical levels) with variable horizontal resolution (mesh grid). The smallest cell has a horizontal dimension less than one hundred meters and the largest cells about 5 km. In spite of model limitations, the model reproduces the main circulation and water pathways in the Brepolen area. Seasonal and annual volume, heat and salt exchanges have been also estimated. The influence of freshwater discharge on shelf-fjord exchange will be also analyzed. The model results allow to study full horizontal and vertical fields of physical parameters (temperature, salinity, sea level variations and currents). The model integration covers only years 2005-2010 and the presented results will be based on this simulation. The project has been financed from the funds of the Leading National Research Centre (KNOW) received by the Centre for Polar Studies for the period 2014-2018

  8. Spatial distribution of juvenile and adult female Tanner crabs (Chionoecetes bairdi) in a glacial fjord ecosystem: Implications for recruitment processes

    USGS Publications Warehouse

    Nielsen, J.K.; Taggart, S.J.; Shirley, T.C.; Mondragon, J.

    2007-01-01

    A systematic pot survey in Glacier Bay, Alaska, was conducted to characterize the spatial distribution of juvenile and adult female Tanner crabs, and their association with depth and temperature. The information was used to infer important recruitment processes for Tanner crabs in glaciated ecosystems. High-catch areas for juvenile and adult female Tanner crabs were identified using local autocorrelation statistics. Spatial segregation by size class corresponded to features in the glacial landscape: high-catch areas for juveniles were located at the distal ends of two narrow glacial fjords, and high-catch areas for adults were located in the open waters of the central Bay. Juvenile female Tanner crabs were found at nearly all sampled depths (15-439 m) and temperatures (4-8??C), but the biggest catches were at depths <150 m where adults were scarce. Because adults may prey on or compete with juveniles, the distribution of juveniles could be influenced by the distribution of adults. Areas where adults or predators are scarce, such as glacially influenced fjords, could serve as refuges for juvenile Tanner crabs. ?? 2007 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

  9. UNIT, ALASKA.

    ERIC Educational Resources Information Center

    Louisiana Arts and Science Center, Baton Rouge.

    THE UNIT DESCRIBED IN THIS BOOKLET DEALS WITH THE GEOGRAPHY OF ALASKA. THE UNIT IS PRESENTED IN OUTLINE FORM. THE FIRST SECTION DEALS PRINCIPALLY WITH THE PHYSICAL GEOGRAPHY OF ALASKA. DISCUSSED ARE (1) THE SIZE, (2) THE MAJOR LAND REGIONS, (3) THE MOUNTAINS, VOLCANOES, GLACIERS, AND RIVERS, (4) THE NATURAL RESOURCES, AND (5) THE CLIMATE. THE…

  10. Recent anthropogenic and climatic history of Nunatsiavut fjords (Labrador, Canada)

    NASA Astrophysics Data System (ADS)

    Richerol, Thomas; Pienitz, Reinhard; Rochon, André

    2014-09-01

    This study aimed at reconstructing past climatic and environmental conditions of a poorly known and documented subarctic region, the Nunatsiavut (northern Labrador). A multiproxy approach was chosen, using fossil dinoflagellate cysts, diatoms and pollen from sediment cores taken into three fjords (Nachvak 59°N, Saglek 58.5°N, and Anaktalak 56.5°N). It allowed estimating terrestrial and marine influences in each fjord and documenting the recent history of human activities of the southern fjords (Saglek and Anaktalak). Fossil pollen and dinoflagellate cyst assemblages allowed depicting the climate history of the region over the last ~200-300 years. In contrast to the general warming trend observed in the arctic and subarctic Canada since the beginning of the Industrial Era, the Nunatsiavut has experienced relative climate stability over this period. Fossil pollen data show a shift of the tree limit to the south illustrating the cooling of terrestrial conditions. Our reconstructions suggest that the Labrador region has remained climatically stable over the last ~150-300 years, with just a slight cooling trend of the reconstructed sea surface temperatures, only perceptible in Saglek and Anaktalak fjords.

  11. Resolving bathymetry from airborne gravity along Greenland fjords

    USGS Publications Warehouse

    Boghosian, Alexandra; Tinto, Kirsty; Cochran, James R.; Porter, David; Elieff, Stefan; Burton, Bethany; Bell, Robin E.

    2015-01-01

    Recent glacier mass loss in Greenland has been attributed to encroaching warming waters, but knowledge of fjord bathymetry is required to investigate this mechanism. The bathymetry in many Greenland fjords is unmapped and difficult to measure. From 2010 to 2012, National Aeronautics and Space Administration's Operation IceBridge collected a unique set of airborne gravity, magnetic, radar, and lidar data along the major outlet glaciers and fjords in Greenland. We applied a consistent technique using the IceBridge gravity data to create 90 bathymetric profiles along 54 Greenland fjords. We also used this technique to recover subice topography where warm or crevassed ice prevents the radar system from imaging the bed. Here we discuss our methodology, basic assumptions and error analysis. We present the new bathymetry data and discuss observations in six major regions of Greenland covered by IceBridge. The gravity models provide a total of 1950 line kilometers of bathymetry, 875 line kilometers of subice topography, and 12 new grounding line depths.

  12. Resolving bathymetry from airborne gravity along Greenland fjords

    NASA Astrophysics Data System (ADS)

    Boghosian, Alexandra; Tinto, Kirsty; Cochran, James R.; Porter, David; Elieff, Stefan; Burton, Bethany L.; Bell, Robin E.

    2015-12-01

    Recent glacier mass loss in Greenland has been attributed to encroaching warming waters, but knowledge of fjord bathymetry is required to investigate this mechanism. The bathymetry in many Greenland fjords is unmapped and difficult to measure. From 2010 to 2012, National Aeronautics and Space Administration's Operation IceBridge collected a unique set of airborne gravity, magnetic, radar, and lidar data along the major outlet glaciers and fjords in Greenland. We applied a consistent technique using the IceBridge gravity data to create 90 bathymetric profiles along 54 Greenland fjords. We also used this technique to recover subice topography where warm or crevassed ice prevents the radar system from imaging the bed. Here we discuss our methodology, basic assumptions and error analysis. We present the new bathymetry data and discuss observations in six major regions of Greenland covered by IceBridge. The gravity models provide a total of 1950 line kilometers of bathymetry, 875 line kilometers of subice topography, and 12 new grounding line depths.

  13. Synoptic events force biological productivity in Patagonian fjord ecosystems

    NASA Astrophysics Data System (ADS)

    Daneri, Giovanni

    2016-04-01

    The annual cycle of primary productivity of the Patagonian fjords has, to date, been described as a two phase system consisting of a short non productive winter phase (during June and July) and a productive phase extending from late winter (August) to autumn (May). Low levels of primary production, phytoplankton biomass and high concentrations of surface nutrients have been described as characterizing winter conditions while pulsed productivity events typifies the productivity pattern during the extended productive season. Pulsed productivity events characterize coastal waters where inorganic nutrients in surface layers are replenished following periods of intensive utilization by autotrophs. Freshwater input in Patagonian fjords in southern Chile (41-55°S) results in one of the largest estuarine regions worldwide. Here strong haline water column stratification prevents nutrient mixing to the surface layers thus potentially shutting off algal production. Our working hypothesis considered that in order to reconcile the observed pulsed productivity pattern, periodic breaking (associated to surface nutrient replenishment) and re-establishment of estuarine conditions (associated to water column stratification) would be required. Up to now however our understanding of the physical processes that control water column conditions in the Patagonian fjord area has been extremely limited. Here we present evidence linking the passage of synoptic low pressure fronts to pulsed productivity events in the Patagonian fjord area. These front controls and influence local processes of interaction between the fjord and the atmosphere generating a rapid water column response. In the specific case of the Puyuhuapi fjord we have been able to show that such synoptic fronts induce surface flow reversal and water column mixing. Phytoplankton blooming occurs after the passage of the synoptic front once calmer conditions prevail and estuarine conditions are re established. The occurrence of

  14. Ocean Observing System Demonstrated in Alaska

    NASA Astrophysics Data System (ADS)

    Schoch, G. Carl; Chao, Yi

    2010-05-01

    To demonstrate the utility of an ocean observing and forecasting system with diverse practical applications—such as search and rescue, oil spill response (perhaps relevent to the current Gulf of Mexico oil spill), fisheries, and risk management—a unique field experiment was conducted in Prince William Sound, Alaska, in July and August 2009. The objective was to quantitatively evaluate the performance of numerical models developed for the sound with an array of fixed and mobile observation platforms (Figure 1). Prince William Sound was chosen for the demonstration because of historical efforts to monitor ocean circulation following the 1989 oil spill from the Exxon Valdez tanker. The sound, a highly crenulated embayment of about 10,000 square kilometers at approximately 60°N latitude along the northern coast of the Gulf of Alaska, includes about 6900 kilometers of shoreline, numerous islands and fjords, and an extensive system of tidewater glaciers descending from the highest coastal mountain range in North America. Hinchinbrook Entrance and Montague Strait are the two main deep water connections with the Gulf of Alaska. The economic base of communities in the region is almost entirely resource-dependent. For example, Cordova's economy is based on commercial fishing and Valdez's economy is supported primarily by the trans-Alaska oil pipeline terminal.

  15. Biogeochemical consequences of an oxygenated intrusion into an anoxic fjord

    PubMed Central

    2014-01-01

    Background This paper is based on the studies of the biogeochemical structure of the water column in the anoxic Fjord Hunnbunn (south-eastern Norway) performed in 2009, 2011 and 2012. This Fjord is an enclosed basin of brackish water separated by a narrow and shallow outlet to the sea with a permanently anoxic layer. We show how an oxygenated intrusion could lead to both positive and negative effects on the ecosystem state in Hunnbunn due to a change in the biogeochemical structure. Results During the stratified periods in 2009 and 2012 the anoxic layer amounted to approximately 10% of the total water volume in the Fjord, while dissolved oxygen (DO) was present in 80-90% of the water. In the autumn of 2011 the water chemistry structure observed in Fjord Hunnbunn was clearly affected by a recent oxygenated intrusion defined by abnormal salinity patterns. This led to a shift of the DO boundary position to shallower depths, resulting in a thicker anoxic layer comprising approximately 40% of the total water volume, with DO present only in approximately 60% of the water. The oxygenated water intrusions led to a twofold decrease of the concentrations of hydrogen sulphide, ammonia, phosphate and silicate in the deep layers with a simultaneous increase of these nutrients and a decrease of the pH level in the surface layers. The concentrations of manganese, iron, and mercury species changed dramatically and in particular revealed a significant supply of iron and methylmercury to the water column. Conclusions Oxic water intrusions into anoxic fjords could lead not only to the flushing of the bottom anoxia, but to a dispersal of sulphidic and low oxygen conditions to the larger bottom area. The elevation of the hydrogen sulphide to the shallower layers (that can be rapidly oxidized) is accompanied by the appearance in the subsurface water of methylmercury, which is easily accumulated by organisms and can be transported to the surrounding waters, affecting the ecosystem over a

  16. Stock structure of sea otters (Enhydra Lutris Kenyoni) in Alaska

    USGS Publications Warehouse

    Gorbics, C.S.; Bodkin, J.L.

    2001-01-01

    Sea otters in Alaska are recognized as a single subspecies (Enhydra lutris kenyoni) and currently managed as a single, interbreeding population. However, geographic and behavioral mechanisms undoubtably constrain sea otter movements on much smaller scales. This paper applies the phylogeographic method (Dizon et al. 1992) and considers distribution, population response, phenotype and genotype data to identify stocks of sea otters within Alaska. The evidence for separate stock identity is genotypic (all stocks), phenotypic (Southcentral and Southwest stocks), and geographic distribution (Southeast stock), whereas population response data are equivocal (all stocks). Differences in genotype frequencies and the presence of unique genotypes among areas indicate restricted gene flow. Genetic exchange may be limited by little or no movement across proposed stock boundaries and discontinuities in distribution at proposed stock boundaries. Skull size differences (phenotypic) between Southwest and Southcentral Alaska populations further support stock separation. Population response information was equivocal in either supporting or refuting stock identity. On the basis of this review, we suggest the following: (1) a Southeast stock extending from Dixon Entrance to Cape Yakataga; (2) a Southcentral stock extending from Cape Yakataga to Cape Douglas including Prince William Sound and Kenai peninsula coast; and (3) a Southwest stock including Alaska Peninsula coast, the Aleutians to Attu Island, Barren, Kodiak, Pribilof Islands, and Bristol Bay.

  17. Transience and Glacial Erosion in South Central Alaska

    NASA Astrophysics Data System (ADS)

    Valentino, J.; Spotila, J. A.; Owen, L. A.; Buscher, J.

    2013-12-01

    It is documented that a glacial presence in active orogenic belts undergoing rapid rock uplift will increase erosion rates often matching rates of rock uplift. Glacial erosion seems to have shaped the mass balance of numerous mountain ranges and tectonic settings, but the Kenai Peninsula and Chugach Mountains of south central Alaska do not conform to this pattern. The Kenai Peninsula is an uplifted forearc forming above the Aleutian subduction zone and the Chugach Mountains are the continuation of the orogenic belt around Prince William Sound. This mountain belt is comprised of accreted Mesozoic island arcs, which were sequentially metamorphosed from the cretaceous through the Tertiary. Geomorphic analysis and past studies, including Buscher et al. (2008) and Arkle et al. (2013), show that the Chugach Mountains and Kenai Peninsula are similar to the Saint Elias Mountains in the Yakutat collision zone with regards to topographic ruggedness. The region is dominated by alpine glaciers, ice fields, and extensive valley glaciers that are actively eroding the topography through headwall erosion and valley glacier down cutting. Despite this, there is a low background long term erosion rate of <0.1-0.2 mm/yr (Buscher et al, 2008). This suggests a transient landscape that has not yet fully adjusted to onset of erosive glacial conditions. Through the use of four dating techniques spanning different timescales, we aim to quantify erosion rates in the Kenai and Chugach Mountains. (U-TH)/He thermochronometry (106-7 yr), He/He thermochronometry (105-6 yr), OSL thermochronometry (105-6 yr), and 10Be and 36CL cosmogenic dating (103-4 yr), are being used in conjunction to test if short-term rates exceed long-term rates, thereby indicating a transient response to late Cenozoic glaciations. This analysis will also address how landscapes respond to the onset of glacial conditions and subsequent climate fluctuations. The history of exhumation and erosion will also characterize the role

  18. Growth of a post-Little Ice Age submarine fan, Glacier Bay, Alaska

    USGS Publications Warehouse

    Carlson, P.R.; Cowan, E.A.; Powell, R.D.; Cai, J.

    1999-01-01

    A small Holocene fan is forming where Queen Inlet, a hanging valley, enters West Arm fjord, Glacier Bay, Alaska. Queen fan formed in the last 80 years following retreat of the Little Ice Age glacier that filled Glacier Bay about 200 yr BP. It was built mainly by a turbidite system originating from Carroll Glacier delta, as the delta formed in the early 1900s at the head of Queen Inlet. The Late Holocene Queen fan is comparable to large Pleistocene fans that formed in the Gulf of Alaska and differs from trough-mouth fans formed by cooler climate glacier systems.

  19. Uranium behavior in a permanently anoxic Fjord: Microbial control

    SciTech Connect

    McKee, B.A. ); Todd, J.F. )

    1993-03-01

    Uranium contamination of groundwaters resulting from U mining activities and the leakage of nuclear waste from storage facilities is a growing concern. In Framvern Fjord (southern Norway), dissolved [sup 238]U concentrations at the bacterial maximum layer (24 m), which is situated a few meters below the oxic-anoxic (i.e. oxygen-hydrogen sulfide) interface (18 m), are observed to be [approximately]60% lower than concentrations above and below this depth. Removal of U occurs well below the depth at which Fe and Mn oxyhydroxides are precipitated and under conditions inconsistent with abiological reduction of soluble U(VI) to particle-reactive U(IV). Our observations suggest that the microbial population in the anoxic waters near the O[sub 2]-H[sub 2]S interface in the fjord exerts an effective control on the aquatic biogeochemistry of U in this environment. 27 refs., 3 figs., 1 tab.

  20. An intersection model for estimating sea otter mortality along the Kenai Peninsula

    USGS Publications Warehouse

    Bodkin, J.L.; Udevitz, M.S.; Loughlin, T.R.

    1994-01-01

    We developed an intersection model to integrate parameters estimated from three distinct data sets that resulted from the Exxon Valdez oil spill: (1) the distribution, amount, and movements of spilled oil; (2) the distribution and abundance of sea otters along the Kenai Peninsula; and (3) the estimates of site-specific sea otter mortality relative to oil exposure from otters captured for rehabilitation and from collected carcasses. In this chapter, we describe the data sets and provide examples of how they can be used in the model to generate acute loss estimates. We also examine the assumptions required for the model and provide suggestions for improving and applying the model.

  1. Oil spill vulnerability, coastal morphology, and sedimentation of outer Kenai Peninsula and Montague Island. Final report

    SciTech Connect

    Hayes, M.O.

    1980-04-01

    The report discusses the results of an extensive study of the geomorphology, sedimentology, and oil-spill vulnerability of the outer Kenai Peninsula and Montague Island shorelines. Major emphasis is placed on the application of an Oil Spill Vulnerability Index (O.S.V.I.). Large segments of the shoreline are high risk environments with respect to oil-spill residence time. Nearly 60% of the study area falls into O.S.V.I. classes 6-10, which indicates any oil spilled would have residence times from one to more than ten years.

  2. Effect of fjord geometry on tidewater glacier stability

    NASA Astrophysics Data System (ADS)

    Åkesson, Henning; Nisancioglu, Kerim H.; Nick, Faezeh M.

    2016-04-01

    Many marine-terminating glaciers have thinned, accelerated and retreated during the last two decades, broadly consistent with warmer atmospheric and oceanic conditions. However, these patterns involve considerable spatial and temporal variability, with diverse glacier behavior within the same regions. Similarly, reconstructions of marine-terminating glaciers indicate highly asynchronous retreat histories. While it is well known that retrograde slopes can cause marine ice sheet instabilities, the effect of lateral drag and fjord width has received less attention. Here, we test the hypothesis that marine outlet glacier stability is largely controlled by fjord width, and to a less extent by regional climate forcing. We employ a dynamic flowline model on idealized glacier geometries (representative of different outlet glaciers) to investigate geometric controls on decadal and longer times scales. The model accounts for driving and resistive stresses of glacier flow as well as along-flow stress transfer. It has a physical treatment of iceberg calving and a time-adaptive grid allowing for continuous tracking of grounding-line migration. We apply changes in atmospheric and oceanic forcing and show how wide and narrow fjord sections foster glacier (in)stabilities. We also evaluate the effect of including a surface mass balance - elevation feedback in such a setting. Finally, the relevance of these results to past and future marine-terminating glacier stability is discussed.

  3. Physical Modeling of Landslide Generated Tsunamis in Fjords and around Conical Islands

    NASA Astrophysics Data System (ADS)

    McFall, B. C.; Fritz, H. M.

    2012-12-01

    Tsunamis generated by landslides and volcanic island collapses account for some of the most extreme events recorded in history (Lituya Bay, Alaska, 1958) and can be particularly catastrophic in the near field region. Source and runup scenarios based on real world events using generalized Froude similarity are physically modeled in the three dimensional NEES tsunami wave basin (TWB) at Oregon State University. A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. The LTG consists of a sliding box filled with up to 1,350 kg of naturally rounded river gravel which is accelerated by means of four pneumatic pistons down the 2H: 1V slope. The granular landslides are launched towards the water surface at velocities of up to 5 m/s resulting in corresponding landslide Froude numbers at impact in the range 1 fjord, a curved headland fjord and a conical island setting representing landslides off an island or a volcanic flank collapse. Measurement instrumentation includes an array of wave and runup wave gauges, above and underwater cameras, a stereo particle image velocimetry (PIV) setup and a multi-transducer acoustic array (MTA). Three-dimensional landslide surfaces are reconstructed and the instantaneous landslide surface kinematics measured using the stereo PIV setup. Above and underwater cameras measure the slide deformation at impact and underwater runout, while the slide deposit is measured with the MTA on the basin floor. Runup wave gauges along with overlapping video cameras record the onshore and offshore runup. Empirical equations for predicting wave amplitude, wave period, wave length and near-source runup are obtained. The generated waves are primarily dependent on non-dimensional landslide and water body parameters such as the impact landslide

  4. Combined High-Resolution LIDAR Topography and Multibeam Bathymetry for Northern Resurrection Bay, Seward, Alaska

    USGS Publications Warehouse

    Labay, Keith A.; Haeussler, Peter J.

    2008-01-01

    A new Digital Elevation Model was created using the best available high-resolution topography and multibeam bathymetry surrounding the area of Seward, Alaska. Datasets of (1) LIDAR topography collected for the Kenai Watershed Forum, (2) Seward harbor soundings from the U.S. Army Corp of Engineers, and (3) multibeam bathymetry from the National Oceanic and Atmospheric Administration contributed to the final combined product. These datasets were placed into a common coordinate system, horizontal datum, vertical datum, and data format prior to being combined. The projected coordinate system of Universal Transverse Mercator Zone 6 North American Datum of 1927 was used for the horizontal coordinates. Z-values in meters were referenced to the tidal datum of Mean High Water. Gaps between the datasets were interpolated to create the final seamless 5-meter grid covering the area of interest around Seward, Alaska.

  5. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 11 2014-10-01 2014-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  6. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  7. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 11 2012-10-01 2012-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  8. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  9. 75 FR 20391 - Agrium U.S., Inc., Kenai Nitrogen Operation, Including On-Site Leased Workers From NMS (Nana...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-19

    ... in the Federal Register on January 16, 2008 (73 FR 2946). The Revised Determination was amended on... published in the Federal Register on November 3, 2008 (73 FR 65410- 65411) At the request of the petitioner... Employment and Training Administration Agrium U.S., Inc., Kenai Nitrogen Operation, Including On-Site...

  10. 50 CFR Figure 5 to Subpart E of... - Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Anchorage, Matanuska-Susitna, and Kenai Rural and Non-Rural Areas 5 Figure 5 to Subpart E of Part 300 Wildlife and Fisheries INTERNATIONAL FISHING AND RELATED ACTIVITIES INTERNATIONAL FISHERIES REGULATIONS Pacific Halibut Fisheries Pt. 300, Subpt. E, Fig. 5 Figure 5 to Subpart E of Part...

  11. Heat, salt, and freshwater budgets for a glacial fjord in Greenland

    NASA Astrophysics Data System (ADS)

    Jackson, R. H.; Straneo, F.

    2015-12-01

    Fjords link the ocean and outlet glaciers of the Greenland ice sheet. As the ice sheet loses mass - potentially triggered by submarine melting - measurements of ocean heat transport in fjords are increasingly being used to diagnose submarine melting and freshwater fluxes. The full budgets that underlie such methods, however, have been largely neglected. Here, we present complete heat, salt, and mass budgets for glacial fjords and new equations for inferring the freshwater fluxes of submarine melting and runoff. Building on estuarine studies of salt budgets, this method includes a decomposition of the fjord transports (into barotropic, exchange, and fluctuating components) that is crucial for conserving mass in the budgets and appropriately accounting for temporal variability. These methods are applied to moored records from Sermilik Fjord, near the terminus of Helheim Glacier, to evaluate the dominant balances in the fjord budgets and to estimate freshwater fluxes. We find two different regimes seasonally that align with the seasonal variations in fjord drivers: shelf variability from barrier winds and freshwater forcing. Our results highlight many important components of fjord budgets, particularly iceberg melting, heat/salt storage and barotropic fluxes, that have been neglected in previous estimates of submarine melting.

  12. Marine benthic habitat mapping of the West Arm, Glacier Bay National Park and Preserve, Alaska

    USGS Publications Warehouse

    Hodson, Timothy O.; Cochrane, Guy R.; Powell, Ross D.

    2013-01-01

    Seafloor geology and potential benthic habitats were mapped in West Arm, Glacier Bay National Park and Preserve, Alaska, using multibeam sonar, groundtruthed observations, and geological interpretations. The West Arm of Glacier Bay is a recently deglaciated fjord system under the influence of glacial and paraglacial marine processes. High glacially derived sediment and meltwater fluxes, slope instabilities, and variable bathymetry result in a highly dynamic estuarine environment and benthic ecosystem. We characterize the fjord seafloor and potential benthic habitats using the recently developed Coastal and Marine Ecological Classification Standard (CMECS) by the National Oceanic and Atmospheric Administration (NOAA) and NatureServe. Due to the high flux of glacially sourced fines, mud is the dominant substrate within the West Arm. Water-column characteristics are addressed using a combination of CTD and circulation model results. We also present sediment accumulation data derived from differential bathymetry. These data show the West Arm is divided into two contrasting environments: a dynamic upper fjord and a relatively static lower fjord. The results of these analyses serve as a test of the CMECS classification scheme and as a baseline for ongoing and future mapping efforts and correlations between seafloor substrate, benthic habitats, and glacimarine processes.

  13. Megafaunal Communities in Rapidly Warming Fjords along the West Antarctic Peninsula: Hotspots of Abundance and Beta Diversity

    PubMed Central

    Grange, Laura J.; Smith, Craig R.

    2013-01-01

    Glacio-marine fjords occur widely at high latitudes and have been extensively studied in the Arctic, where heavy meltwater inputs and sedimentation yield low benthic faunal abundance and biodiversity in inner-middle fjords. Fjord benthic ecosystems remain poorly studied in the subpolar Antarctic, including those in extensive fjords along the West Antarctic Peninsula (WAP). Here we test ecosystem predictions from Arctic fjords on three subpolar, glacio-marine fjords along the WAP. With seafloor photographic surveys we evaluate benthic megafaunal abundance, community structure, and species diversity, as well as the abundance of demersal nekton and macroalgal detritus, in soft-sediment basins of Andvord, Flandres and Barilari Bays at depths of 436–725 m. We then contrast these fjord sites with three open shelf stations of similar depths. Contrary to Arctic predictions, WAP fjord basins exhibited 3 to 38-fold greater benthic megafaunal abundance than the open shelf, and local species diversity and trophic complexity remained high from outer to inner fjord basins. Furthermore, WAP fjords contained distinct species composition, substantially contributing to beta and gamma diversity at 400–700 m depths along the WAP. The abundance of demersal nekton and macroalgal detritus was also substantially higher in WAP fjords compared to the open shelf. We conclude that WAP fjords are important hotspots of benthic abundance and biodiversity as a consequence of weak meltwater influences, low sedimentation disturbance, and high, varied food inputs. We postulate that WAP fjords differ markedly from their Arctic counterparts because they are in earlier stages of climate warming, and that rapid warming along the WAP will increase meltwater and sediment inputs, deleteriously impacting these biodiversity hotspots. Because WAP fjords also provide important habitat and foraging areas for Antarctic krill and baleen whales, there is an urgent need to develop better understanding of the

  14. Megafaunal communities in rapidly warming fjords along the West Antarctic Peninsula: hotspots of abundance and beta diversity.

    PubMed

    Grange, Laura J; Smith, Craig R

    2013-01-01

    Glacio-marine fjords occur widely at high latitudes and have been extensively studied in the Arctic, where heavy meltwater inputs and sedimentation yield low benthic faunal abundance and biodiversity in inner-middle fjords. Fjord benthic ecosystems remain poorly studied in the subpolar Antarctic, including those in extensive fjords along the West Antarctic Peninsula (WAP). Here we test ecosystem predictions from Arctic fjords on three subpolar, glacio-marine fjords along the WAP. With seafloor photographic surveys we evaluate benthic megafaunal abundance, community structure, and species diversity, as well as the abundance of demersal nekton and macroalgal detritus, in soft-sediment basins of Andvord, Flandres and Barilari Bays at depths of 436-725 m. We then contrast these fjord sites with three open shelf stations of similar depths. Contrary to Arctic predictions, WAP fjord basins exhibited 3 to 38-fold greater benthic megafaunal abundance than the open shelf, and local species diversity and trophic complexity remained high from outer to inner fjord basins. Furthermore, WAP fjords contained distinct species composition, substantially contributing to beta and gamma diversity at 400-700 m depths along the WAP. The abundance of demersal nekton and macroalgal detritus was also substantially higher in WAP fjords compared to the open shelf. We conclude that WAP fjords are important hotspots of benthic abundance and biodiversity as a consequence of weak meltwater influences, low sedimentation disturbance, and high, varied food inputs. We postulate that WAP fjords differ markedly from their Arctic counterparts because they are in earlier stages of climate warming, and that rapid warming along the WAP will increase meltwater and sediment inputs, deleteriously impacting these biodiversity hotspots. Because WAP fjords also provide important habitat and foraging areas for Antarctic krill and baleen whales, there is an urgent need to develop better understanding of the

  15. Linkage of ocean and fjord dynamics at decadal period

    NASA Astrophysics Data System (ADS)

    Ebbesmeyer, Curtis C.; Coomes, Carol A.; Cannon, Glenn A.; Bretschneider, Dale E.

    At decadal period (10-20 years), dynamic linkage was evident between atmospheric low pressure systems over the North Pacific Ocean and circulation in a Pacific Northwest fjord (Puget Sound). As the Aleutian low pressure center shifts, storms arriving from the North Pacific Ocean deposit varying amounts of precipitation in the mountains draining into the estuarine system; in turn, the fluctuating addition of fresh water changes the density distribution near the fjord basin entrance sill, thereby constraining the fjord's vertical velocity structure. The linkage was examined using time series of 21 environmental parameters which covaried between the 2 regimes associated with cycling of the Aleutian Low between its eastern and westernmost winter positions. Observations from 1899 to 1987 suggest that, in the 20th century, approximately 5 cycles may have occurred between these regimes. Covariation in all but one of the time series (Puget Sound's main basin salinity) occurred because of the high degree of correlation between parameters and the strong decadal cycles compared with long-term averages, interannual variability, and seasonal cycles. Basin salinity was relatively steady due to opposing influences of oceanic source/water salinity and the addition of fresh water in each regime. However, the decadal signal for the other parameters characterizing Puget Sound water are apparently amplified twofold compared with that of the atmosphere over the North Pacific Ocean. "As to Holmes, I observed that he sat frequently for half an hour on end, with knitted brows and an abstracted air, but he swept the matter away with a wave of his hand when I mentioned it". "Data! data! data!" he cried impatiently. "I can't make bricks without clay." A. Conan Doyle The Adventure of the Copper Beeches

  16. Organic carbon in glacial fjords of Chilean Patagonia

    NASA Astrophysics Data System (ADS)

    Pantoja, Silvio; Gutiérrez, Marcelo; Tapia, Fabián; Abarzúa, Leslie; Daneri, Giovanni; Reid, Brian; Díez, Beatriz

    2016-04-01

    The Southern Ice Field in Chilean Patagonia is the largest (13,000 km2) temperate ice mass in the Southern hemisphere, yearly transporting ca. 40 km3 of freshwater to fjords. This volume of fresh and cold water likely affects adjacent marine ecosystems by changing circulation, productivity, food web dynamics, and the abundance and distribution of planktonic and benthic organisms. We hypothesize that freshwater-driven availability of inorganic nutrient and transport of organic and inorganic suspended matter, as well as microbes, become a controlling factor for productivity in the fjord associated with the Baker river and Jorge Montt glacier. Both appear to be sources of silicic acid, but not of nitrate and particulate organic carbon, especially during summer, when surface PAR and glacier thawing are maximal. In contrast to Baker River, the Jorge Montt glacier is also a source of dissolved organic carbon towards a proglacial fjord and the Baker Channel, indicating that a thorough chemical description of sources (tidewater glacier and glacial river) is needed. Nitrate in fiord waters reaches ca. 15 μM at 25 m depth with no evidence of mixing up during summer. Stable isotope composition of particulate organic nitrogen reaches values as low as 3 per mil in low-salinity waters near both glacier and river. Nitrogen fixation could be depleting δ15N in organic matter, as suggested by the detection at surface waters of nif H genes belonging to diazotrophs near the Montt glacier. As diazotrophs have also been detected in other cold marine waters (e.g. Baltic Sea, Arctic Ocean) as well as glaciers and polar terrestrial waters, there is certainly a potential for both marine and freshwater microbes to contribute and have a significant impact on the Patagonian N and C budgets. Assessing the impact of freshwater on C and N fluxes and the microbial community structure in Patagonian waters will allow understanding future scenarios of rapid glacier melting. This research was funded

  17. Twilight vertical migrations of zooplankton in a Chilean fjord

    NASA Astrophysics Data System (ADS)

    Valle-Levinson, Arnoldo; Castro, Leonardo; Cáceres, Mario; Pizarro, Oscar

    2014-12-01

    Time series of acoustic backscatter and vertical velocity profiles were obtained at three sites along a Chilean fjord with the purpose of determining dominant structures of vertical migrations of the sound scattering layer. Ancillary data obtained with stratified net samples indicated that the sound scattering layer may have been dominated by euphausiids and decapods. Therefore, distributions of acoustic backscatter anomalies and vertical velocities were attributed to vertical migrations of predominantly these organisms. Migration patterns were dominated by twilight excursions in which organisms swam toward the water surface at sunset, spent <0.5 h at a depth near the pycnocline (∼10 m) and then swam downward to depths between ∼20 and ∼60 m. After congregating at those depths during night-time, organisms swam upward again toward the pycnocline at sunrise, spent <1 h near the pycnocline and swam downward to their day-time depths (>100 m). This migration strategy can also be termed 'semidiel migration' as two double excursions were linked to light levels. The reasons for this twilight migration remain uncertain. But it is possible that the up and down motion around sunset was related to predation avoidance, hunger-satiation state, ontogeny, seaward transport evasion, or reaction to the environmental shock from the pycnocline, or a combination of all or some of them. In contrast, the sunrise double excursion was probably linked to feeding requirements by organisms that need to spend the day at great depth with no food available. This study demonstrated the existence of semidiel patterns throughout the fjord and through prolonged periods. In addition, identification of this pattern by acoustic backscatter was complemented by direct vertical velocity measurements. It is proposed that twilight vertical migration is a common strategy in Chilean fjords.

  18. A new alcyonacean octocoral (Cnidaria, Anthozoa, Octocorallia) from Chilean fjords.

    PubMed

    Breedy, Odalisca; Cairns, Stephen D; Häussermann, Verena

    2015-01-01

    A new species, Swiftia comauensis, is described from Chile. It occurs in shallow waters from 18 to 59 m in the Patagonian fjord region and seems to be endemic to the northern part of the region. The species is characterized by having straggly colonies with sparse branching and long drooping branches, prominent polyp mounds, and long, thin spindles; the colonies are bright orange with pale yellow polyp mounds. A sharp decline in colony abundance was observed between 2003 and 2013, and in January 2014 a proposal was submitted to the IUCN for the addition of this taxon to the Red List of Threatened Species. PMID:25781130

  19. Increased prevalence of antibiotic-resistant E. coli in gulls sampled in Southcentral Alaska is associated with urban environments

    PubMed Central

    Atterby, Clara; Ramey, Andrew M.; Hall, Gabriel Gustafsson; Järhult, Josef; Börjesson, Stefan; Bonnedahl, Jonas

    2016-01-01

    Background Antibiotic-resistant bacteria pose challenges to healthcare delivery systems globally; however, limited information is available regarding the prevalence and spread of such bacteria in the environment. The aim of this study was to compare the prevalence of antibiotic-resistant bacteria in large-bodied gulls (Larus spp.) at urban and remote locations in Southcentral Alaska to gain inference into the association between antibiotic resistance in wildlife and anthropogenically influenced habitats. Methods Escherichia coli was cultured (n=115 isolates) from fecal samples of gulls (n=160) collected from a remote location, Middleton Island, and a more urban setting on the Kenai Peninsula. Results Screening of E. coli from fecal samples collected from glaucous-winged gulls (Larus glaucescens) at Middleton Island revealed 8% of isolates were resistant to one or more antibiotics and 2% of the isolates were resistant to three or more antibiotics. In contrast, 55% of E. coli isolates derived from fecal samples collected from large-bodied gulls (i.e. glaucous, herring [Larus argentatus], and potentially hybrid gulls) on the Kenai Peninsula were resistant to one or more antibiotics and 22% were resistant to three or more antibiotics. In addition, total of 16% of the gull samples from locations on the Kenai Peninsula harbored extended-spectrum cephalosporin-resistant E. coli isolates (extended-spectrum beta-lactamases [ESBL] and plasmid-encoded AmpC [pAmpC]), in contrast to Middleton Island where no ESBL- or pAmpC-producing isolates were detected. Conclusion Our findings indicate that increased prevalence of antibiotic resistance is associated with urban environments in Southcentral Alaska and presumably influenced by anthropogenic impacts. Further investigation is warranted to assess how migratory birds may maintain and spread antimicrobial-resistant bacteria of relevance to human and animal health. PMID:27649798

  20. Massive submarine slope failures during the 1964 earthquake in Port Valdez, Alaska

    NASA Astrophysics Data System (ADS)

    Lee, H. J.; Ryan, H. F.; Suleimani, E.; Haeussler, P. A.; Kayen, R. E.; Hampton, M. A.

    2006-12-01

    The M9.2 Alaska earthquake of 1964 caused major damage to the port facilities and town of Valdez, resulting in a total of 32 deaths. Most of the damage and deaths in Valdez were caused by submarine-landslide generated tsunamis that occurred immediately after the earthquake. Some post-earthquake investigations were conducted in the 1960's. Dramatic changes in bathymetry were observed, including several hundred meters of deepening below the head of Port Valdez fjord, and these were attributed to submarine landsliding. Recent multibeam surveys of Port Valdez provide much more information about the morphology of landslide deposits. Also, we collected high-resolution (chirp) surveys over apparent landslide debris to evaluate the chronology and three-dimensional character of the deposits, and we performed quantitative evaluations of pre- and post-earthquake bathymetric data. Landslide morphologies include several forms. In the western part of the fjord, there is a field of large blocks (up to 40-m high) on the fjord floor near the location of the greatest tsunami-wave runup estimated for the 1964 earthquake (~50 m). The runup direction for the waves (northeast) is consistent with the failure of these blocks being the trigger. Surrounding the fields of blocks are lobes from two debris flows that likely occurred at the same time as the block slides. Both debris flows and block slides appear to have resulted from the failure of a large moraine front, formed by Shoup Glacier on the northwest side of Port Valdez. At the fjord head, near the location of the badly damaged old town of Valdez, is an intricate series of gullies, channels, and talus, although these features display little evidence for the large-scale mass movement that occurred. However, near the center of the fjord is the front of a large debris lobe that flowed from the east end of the fjord half-way down the fjord and stopped. This huge deposit represents material that failed at the fjord head, mobilized into a

  1. Controlled artificial upwelling in a fjord to combat toxic algae

    NASA Astrophysics Data System (ADS)

    McClimans, T. A.; Hansen, A. H.; Fredheim, A.; Lien, E.; Reitan, K. I.

    2003-04-01

    During the summer, primary production in the surface layers of some fjords depletes the nutrients to the degree that some arts of toxic algae dominate the flora. We describe an experiment employing a bubble curtain to lift significant amounts of nutrient-rich seawater to the light zone and provide an environment in which useful algae can survive. The motivation for the experiment is to provide a local region in which mussels can be cleansed from the effects of toxic algae. Three 100-m long, perforated pipes were suspended at 40 m depth in the Arnafjord, a side arm of the Sognefjord. Large amounts of compressed air were supplied during a period of three weeks. The deeper water mixed with the surface water and flowed from the mixing region at 5 to 15 m depth. Within a few days, the mixture of nutrient-rich water covered most of the inner portion of Arnafjord. Within 10 days, the plankton samples showed that the artificial upwelling produced the desired type of algae and excluded the toxic blooms that were occurring outside the manipulated fjord arm. The project (DETOX) is supported by the Norwegian ministries of Fisheries, Agriculture and Public Administration.

  2. Archean metamorphic sequence and surfaces, Kangerdlugssuaq Fjord, East Greenland

    NASA Technical Reports Server (NTRS)

    Kays, M. A.

    1986-01-01

    The characteristics of Archean metamorphic surfaces and fabrics of a mapped sequence of rocks older than about 3000 Ma provide information basic to an understanding of the structural evolution and metamorphic history in Kangerdlugssuaq Fjord, east Greenland. This information and the additional results of petrologic and geochemical studies have culminated in an extended chronology of Archean plutonic, metamorphic, and tectonic events. The basis for the chronology is considered, especially the nature of the metamorphic fabrics and surfaces in the Archean sequence. The surfaces, which are planar mineral parageneses, may prove to be mappable outside Kangerdlugssuaq Fjord, and if so, will be helpful in extending the events that they represent to other Archean sequences in east Greenland. The surfaces will become especially important reference planes if the absolute ages of their metamorphic assemblages can be determined in at least one location where strain was low subsequent to their recrystallization. Once an isochron is obtained, the dynamothermal age of the regionally identifiable metamorphic surface is determined everywhere it can be mapped.

  3. Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar.

    PubMed

    Bunkin, Alexey F; Klinkov, Vladimir K; Lednev, Vasily N; Lushnikov, Dmitry L; Marchenko, Aleksey V; Morozov, Eugene G; Pershin, Sergey M; Yulmetov, Renat N

    2012-08-01

    A compact Raman lidar system for remote sensing of sea and drifting ice was developed at the Wave Research Center at the Prokhorov General Physics Institute of the Russian Academy of Sciences. The developed system is based on a diode-pumped solid-state YVO(4):Nd laser combined with a compact spectrograph equipped with a gated detector. The system exhibits high sensitivity and can be used for mapping or depth profiling of different parameters within many oceanographic problems. Light weight (∼20 kg) and low power consumption (300 W) make it possible to install the device on any vehicle, including unmanned aircraft or submarine systems. The Raman lidar presented was used for study and analysis of the different influence of the open sea and glaciers on water properties in Svalbard fjords. Temperature, phytoplankton, and dissolved organic matter distributions in the seawater were studied in the Ice Fjord, Van Mijen Fjord, and Rinders Fjord. Drifting ice and seawater in the Rinders Fjord were characterized by the Raman spectroscopy and fluorescence. It was found that the Paula Glacier strongly influences the water temperature and chlorophyll distributions in the Van Mijen Fjord and Rinders Fjord. Possible applications of compact lidar systems for express monitoring of seawater in places with high concentrations of floating ice or near cold streams in the Arctic Ocean are discussed. PMID:22859038

  4. Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar.

    PubMed

    Bunkin, Alexey F; Klinkov, Vladimir K; Lednev, Vasily N; Lushnikov, Dmitry L; Marchenko, Aleksey V; Morozov, Eugene G; Pershin, Sergey M; Yulmetov, Renat N

    2012-08-01

    A compact Raman lidar system for remote sensing of sea and drifting ice was developed at the Wave Research Center at the Prokhorov General Physics Institute of the Russian Academy of Sciences. The developed system is based on a diode-pumped solid-state YVO(4):Nd laser combined with a compact spectrograph equipped with a gated detector. The system exhibits high sensitivity and can be used for mapping or depth profiling of different parameters within many oceanographic problems. Light weight (∼20 kg) and low power consumption (300 W) make it possible to install the device on any vehicle, including unmanned aircraft or submarine systems. The Raman lidar presented was used for study and analysis of the different influence of the open sea and glaciers on water properties in Svalbard fjords. Temperature, phytoplankton, and dissolved organic matter distributions in the seawater were studied in the Ice Fjord, Van Mijen Fjord, and Rinders Fjord. Drifting ice and seawater in the Rinders Fjord were characterized by the Raman spectroscopy and fluorescence. It was found that the Paula Glacier strongly influences the water temperature and chlorophyll distributions in the Van Mijen Fjord and Rinders Fjord. Possible applications of compact lidar systems for express monitoring of seawater in places with high concentrations of floating ice or near cold streams in the Arctic Ocean are discussed.

  5. The Dynamics of Greenland's Glacial Fjords and Their Role in Climate.

    PubMed

    Straneo, Fiamma; Cenedese, Claudia

    2015-01-01

    Rapid mass loss from the Greenland Ice Sheet has sparked interest in its glacial fjords for two main reasons: Increased submarine melting of glaciers terminating in fjords is a plausible trigger for glacier retreat, and the anomalous freshwater discharged from Greenland is transformed by fjord processes before being released into the large-scale ocean. Knowledge of the fjords' dynamics is thus key to understanding ice sheet variability and its impact on climate. Although Greenland's fjords share some commonalities with other fjords, their deep sills and deeply grounded glaciers, the presence of Atlantic and Polar Waters on the continental shelves outside the fjords' mouths, and the seasonal discharge at depth of large amounts of surface melt make them unique systems that do not fit existing paradigms. Major gaps in understanding include the interaction of the buoyancy-driven circulation (forced by the glacier) and shelf-driven circulation, and the dynamics in the near-ice zone. These must be addressed before appropriate forcing conditions can be supplied to ice sheet and ocean/climate models.

  6. Oxygen intrusion into anoxic fjords leads to increased methylmercury availability

    NASA Astrophysics Data System (ADS)

    Veiteberg Braaten, Hans Fredrik; Pakhomova, Svetlana; Yakushev, Evgeniy

    2013-04-01

    Mercury (Hg) appears in the oxic surface waters of the oceans at low levels (sub ng/L). Because inorganic Hg can be methylated into the toxic and bioaccumulative specie methylmercury (MeHg) levels can be high at the top of the marine food chain. Even though marine sea food is considered the main risk driver for MeHg exposure to people most research up to date has focused on Hg methylation processes in freshwater systems. This study identifies the mechanisms driving formation of MeHg during oxygen depletion in fjords, and shows how MeHg is made available in the surface water during oxygen intrusion. Studies of the biogeochemical structure in the water column of the Norwegian fjord Hunnbunn were performed in 2009, 2011 and 2012. In autumn of 2011 mixing flushing events were observed and lead to both positive and negative effects on the ecosystem state in the fjord. The oxygenated water intrusions lead to a decrease of the deep layer concentrations of hydrogen sulfide (H2S), ammonia and phosphate. On the other hand the intrusion also raised the H2S boundary from 8 m to a shallower depth of just 4 m. Following the intrusion was also observed an increase at shallower depths of nutrients combined with a decrease of pH. Before flushing events were observed concentrations of total Hg (TotHg) increased from 1.3 - 1.7 ng/L in the surface layer of the fjord to concentrations ranging from 5.2 ng/L to 6.4 ng/L in the anoxic zone. MeHg increased regularly from 0.04 ng/L in the surface water to a maximum concentration of 5.2 ng/L in the deeper layers. This corresponds to an amount of TotHg present as MeHg ranging from 2.1 % to 99 %. The higher concentrations of MeHg in the deeper layer corresponds to an area where no oxygen is present and concentrations of H2S exceeds 500 µM, suggesting a production of MeHg in the anoxic area as a result of sulphate reducing bacteria activity. After flushing the concentrations of TotHg showed a similar pattern ranging from 0.6 ng/L in the

  7. Monitoring of sea currents and waves in Spitsbergen fjords

    NASA Astrophysics Data System (ADS)

    Marchenko, Nataliya; Brazhnikov, Dmitry; Marchenko, Aleksey; Finseth, Jomar

    2014-05-01

    Investigation of sea currents and waves in Spitsbergen fjords has both pure scientific and practical value. It allows to understand the processes in the fjords and to get idea about functioning of World Ocean. From practical point of view such measurements can give information about sediment transport, coastal erosion processes and sea ice behavior in winter, which is important for port construction and industry in shore zone. It has special meaning for Adventfjorden, because of Longyearbyen, a town with 2,500 citizens, with large tourist, scientific and economic activities and growing importance as base for rescue and pollution preparedness for significant part of Arctic. UNIS researchers and colleagues have performed studies of sea currents in fjords over several years. Field investigations in Adventfjorden (ADCP, drift trackers) in 2012-2013 are in the center of the presentation. Adventfjorden is a rather small (7x4 km) side-fjord on the south of Isfjorden, directed 135° (NW-SE). Isfjorden is second longest (107 km) fjord of Spitsbergen, influenced by West Spitsbergen current. The ADCP AWAC (producer Nordtek) was installed and collecting data 10.09.2012-25.10.2013 in a point of Adventfjorden and Isfjorden connection; 563 m from shore line, 16 m depth. One year of data collection for waves and currents parameters, pressure, temperature and salinity and comparison with meteodata has allowed to compose the picture of water movement. Data had been processed in AWAC, Storm and Origin software. Studying surface water flow in Adventfjorden was performed by using GPS transmitters "Garmin DC40" and receiver "Garmin AstroDog 320". To avoid effect of wind and wave motions, GPS transmitters had been mounted on PVC frames with 4 textiles sails (1mx0.5m). Floating rings was used for buoyancy. 3 such devices freely moved/sailed following the currents during 3 days in October 2013. It allowed covering all tidal variations and some weather changings. To analyze resulted tracks

  8. Alaska Resource Data File, Noatak Quadrangle, Alaska

    USGS Publications Warehouse

    Grybeck, Donald J.; Dumoulin, Julie A.

    2006-01-01

    This report gives descriptions of the mineral occurrences in the Noatak 1:250,000-scale quadrangle, Alaska. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska.

  9. Abundance, trends and distribution of baleen whales off Western Alaska and the central Aleutian Islands

    NASA Astrophysics Data System (ADS)

    Zerbini, Alexandre N.; Waite, Janice M.; Laake, Jeffrey L.; Wade, Paul R.

    2006-11-01

    Large whales were extensively hunted in coastal waters off Alaska, but current distribution, population sizes and trends are poorly known. Line transect surveys were conducted in coastal waters of the Aleutian Islands and the Alaska Peninsula in the summer of 2001-2003. Abundances of three species were estimated by conventional and multiple covariate distance sampling (MCDS) methods. Time series of abundance estimates were used to derive rates of increase for fin whales ( Balaenoptera physalus) and humpback whales ( Megaptera novaeangliae). Fin whales occurred primarily from the Kenai Peninsula to the Shumagin Islands, but were abundant only near the Semidi Islands and Kodiak. Humpback whales were found from the Kenai Peninsula to Umnak Island and were more abundant near Kodiak, the Shumagin Islands and north of Unimak Pass. Minke whales ( B. acutorostrata) occurred primarily in the Aleutian Islands, with a few sightings south of the Alaska Peninsula and near Kodiak Island. Humpback whales were observed in large numbers in their former whaling grounds. In contrast, high densities of fin whales were not observed around the eastern Aleutian Islands, where whaling occurred. Average abundance estimates (95% CI) for fin, humpback and minke whales were 1652 (1142-2389), 2644 (1899-3680), and 1233 (656-2315), respectively. Annual rates of increase were estimated at 4.8% (95% CI=4.1-5.4%) for fin and 6.6% (5.2-8.6%) for humpback whales. This study provides the first estimate of the rate of increase of fin whales in the North Pacific Ocean. The estimated trends are consistent with those of other recovering baleen whales. There were no sightings of blue or North Pacific right whales, indicating the continued depleted status of these species.

  10. Holocene earthquake-triggered turbidites from the Saguenay (Eastern Canada) and Reloncavi (Chilean margin) fjords

    NASA Astrophysics Data System (ADS)

    St-Onge, Guillaume; Chapron, Emmanuel; Mulsow, Sandor; Salas, Marcos; Debret, Maxime; Foucher, Anthony; Mulder, Thierry; Desmet, Marc; Costa, Pedro; Ghaleb, Bassam; Locat, Jacques

    2013-04-01

    Fjords are unique archives of climatic and environmental changes, but also of natural hazards. They can preserve thick sedimentary sequences deposited under very high sediment accumulation rates, making them ideally suited to record historical and pre-historical sedimentological events such as major landslides, floods or earthquakes. In fact, by carefully characterizing and dating the sediments and by comparing the basin fill seismic stratigraphy and sedimentary records with historical events, it is possible to "calibrate" recent rapidly deposited layers such as turbidites with a trigger mechanism and extend these observations further back in time by using seismic reflection profiles and longer sediment cores. Here, we will compare earthquake-triggered turbidites in fjords from the Southern and Northern Hemispheres: the Saguenay (Eastern Canada) and Reloncavi fjords (southern Chilean margin). In both settings, we will first look at basin fill geometries and at the sedimentological properties of historical events before extending the records further back in time. In both fjords, several turbidites were associated with large magnitude historic and pre-historic earthquakes including the 1663 AD (M>7) earthquake in the Saguenay Fjord, and the 1960 (M 9.5), 1837 (M~8) and 1575 AD major Chilean subduction earthquakes in the Reloncavi Fjord. In addition, a sand layer with sea urchin fragments and the exoscopic characteristics typical of a tsunami deposit was observed immediately above the turbidite associated with the 1575 AD earthquake in the Reloncavi Fjord and supports both the chronology and the large magnitude of that historic earthquake. In both fjords, as well as in other recently recognized earthquake-triggered turbidites, the decimeter-to meter-thick normally-graded turbidites are characterized by a homogeneous, but slightly fining upward tail. Finally, new radiocarbon results will be presented and indicate that at least 19 earthquake-triggered turbidites were

  11. Allochthonous subsidies of organic matter across a lake-river-fjord landscape in the Chilean Patagonia: Implications for marine zooplankton in inner fjord areas

    NASA Astrophysics Data System (ADS)

    Vargas, Cristian A.; Martinez, Rodrigo A.; San Martin, Valeska; Aguayo, Mauricio; Silva, Nelson; Torres, Rodrigo

    2011-03-01

    Ecosystems can act as both sources and sinks of allochthonous nutrients and organic matter. In this sense, fjord ecosystems are a typical interface and buffer zone between freshwater systems, glaciated continents, and the coastal ocean. In order to evaluate the potential sources and composition of organic matter across fjord ecosystems, we characterized particulate organic matter along a lake-river-fjord corridor in the Chilean Patagonia using stable isotope (δ 13C) and lipid (fatty acid composition) biomarker analyses. Furthermore, estimates of zooplankton carbon ingestion rates and measurements of δ 13C and δ 15N in zooplankton (copepods) were used to evaluate the implications of allochthonous subsidies for copepods inhabiting inner fjord areas. Our results showed that riverine freshwater flows contributed an important amount of dissolved silicon but, scarce nitrate and phosphate to the brackish surface layer of the fjord ecosystem. Isotopic signatures of particulate organic matter from lakes and rivers were distinct from their counterparts in oceanic influenced stations. Terrestrial allochthonous sources could support around 68-86% of the particulate organic carbon in the river plume and glacier melting areas, whereas fatty acid concentrations were maximal in the surface waters of the Pascua and Baker river plumes. Estimates of carbon ingestion rates and δ 13C in copepods from the river plume areas indicated that terrestrial carbon could account for a significant percentage of the copepod body carbon (20-50%) during periods of food limitation. Particulate organic matter from the Pascua River showed a greater allochthonous contribution of terrigenous/vascular plant sources. Rivers may provide fjord ecosystems with allochthonous contributions from different sources because of the distinct vegetation coverage and land use along each river's watershed. These observations have significant implications for the management of local riverine areas in the context of

  12. Reassessment of seismically induced, tsunamigenic submarine slope failures in Port Valdez, Alaska, USA

    USGS Publications Warehouse

    Lee, H.J.; Haeussler, P.J.; Kayen, R.E.; Hampton, M.A.; Locat, Jacques; Suleimani, E.; Alexander, C.R.

    2007-01-01

    The M9.2 Alaska earthquake of 1964 caused major damage to the port facilities and town of Valdez, most of it the result of submarine landslide and the consequent tsunamis. Recent bathymetric multibeam surveys, high-resolution subbottom profiles, and dated sediment cores in Port Valdez supply new information about the morphology and character of the landslide deposits. A comparison of pre- and post-earthquake bathymetry provides an estimate of the net volume of landslide debris deposited in the basin and the volume of sediment removed from the source region. Landslide features include (1) large blocks (up to 40-m high) near the location of the greatest tsunamiwave runup (~50 m), (2) two debris lobes associated with the blocks, (3) a series of gullies, channels and talus, near the fjord-head delta and badly damaged old town of Valdez, and (4) the front of a debris lobe that flowed half-way down the fjord from the east end.

  13. Earthquakes, Subaerial and Submarine Landslides, Tsunamis and Volcanoes in Aysén Fjord, Chile

    NASA Astrophysics Data System (ADS)

    Lastras, G.; Amblas, D.; Calafat-Frau, A. M.; Canals, M.; Frigola, J.; Hermanns, R. L.; Lafuerza, S.; Longva, O.; Micallef, A.; Sepulveda, S. A.; Vargas Easton, G.; Azpiroz, M.; Bascuñán, I.; Duhart, P.; Iglesias, O.; Kempf, P.; Rayo, X.

    2014-12-01

    The Aysén fjord, 65 km long and east-west oriented, is located at 45.4ºS and 73.2ºW in Chilean Patagonia. It has a maximum water depth of 345 m. It collects the inputs of Aysén, Pescado, Condor and Cuervo rivers, which drain the surrounding Patagonian Andes. The fjord is crossed by the Liquiñe-Ofqui Fault Zone, a seismically active trench parallel intra-arc fault system. On 21 April 2007, an Mw 6.2 earthquake triggered numerous subaerial and submarine landslides along the fjord flanks. Some of the subaerial landslides reached the water mass, generating tsunami-like displacement waves that flooded the adjacent coastlines, withlocal >50 m high run-ups, causing ten fatalities and damage to salmon farms. The research cruise DETSUFA on board BIO Hespérides in March 2013, aiming to characterise the landslides and their effects, mapped with great detail the submerged morphology of the fjord. Multibeam data display deformation structures created by the impact of the landslides in the inner fjord floor. Landslide material descended and accelerated down the highly sloping fjord flanks, and reached the fjord floor at 200 m water depth generating large, 10-m-deep impact depressions. Fjord floor sediment was pushed and piled up in arcuate deformation areas formed by 15-m-high compressional ridges, block fields and a narrow frontal depression. Up to six >1.5 km2 of these structures have been identified. In addition, the cruise mapped the outer fjord floor beyond the Cuervo ridge. This ridge, previously interpreted as a volcanic transverse structure, most probably acted as a limit for grounding ice in the past, as suggested by the presence of a melt-water channel. The fjord smoothens and deepens to more than 330 m forming an enclosed basin, before turning SW across a field of streamlined hills of glacial origin. Three volcanic cones, one of them forming Isla Colorada and the other two totally submerged and previously unknown, have been mapped in the outer fjord. The largest

  14. Reclamation and groundwater remediation at a hydrocarbon site in Alaska

    SciTech Connect

    Ririe, G.T.; Drake, L.D.; Olson, S.S.

    1997-12-31

    As part of a joint hydrocarbon cleanup project between Unocal and Marathon, we have initiated the use of constructed wetlands for restoration of the 40-acre Poppy Lane gravel pit located near Kenai, Alaska. Gravel excavated from this site was used to construct roads and drilling pads in the 1960`-70`s. During this period it was also used as a refuse dump for waste from the Kenai gas field and from local residents. The bulk wastes were removed and pockets of oily sand were removed, treated and returned to a stockpile on the site. This left the site with residual pockets of hydrocarbon-impacted sand (<1000 TPH) plus traces of hydrocarbon contamination in the uppermost shallow groundwater flowing through the outwash gravels. The final part of the cleanup will be land restoration and bioremediation of the final traces of hydrocarbons, which are predominantly diesel-range. High resolution gas chromatography analysis indicated that common plants already growing on the site (willow, cottonwood, and alder) did not concentrate diesel-range petroleum hydrocarbons in their foliage when growing in soils containing these contaminants. As part of the planned restoration and shallow groundwater remediation, two 1/3 acre test plots were constructed to promote in-situ biodegradation processes. In spring 1995, the first test, a tree root-barrier plot, was planted with dormant cuttings of four native wetland tree and shrub species, which were planted to depths up to five feet. Alder and elderberry did not succeed under any conditions, nor did any species planted in standing water. For cottonwood and willow species, approximately one half of each rooted and survived. When the water table dropped the second year, the willow cuttings rooted deeper in the vadose zone, while cottonwood did not. As a result of these findings, a tree root-barrier wetland is not considered to be a viable option for groundwater treatment at Poppy Lane.

  15. Global Warming and Glaciers Melting at Fjords in Greenland

    NASA Astrophysics Data System (ADS)

    Coelho, Pablo

    2015-04-01

    This paper presents a discussion on the validation or not of a likely paradigm about the melting of polar glaciers and their direct impact on increasing ocean levels. Physico-chemical properties of ocean waters, as well as anomalies in the thermal behavior of water are used as providers of this discussion using fjords of Greenland as study area. This text seeks to infer the relationship between the most recent developments in global warming, specifically dealing with the melting of glaciers located in fjords in the eastern part of Greenland, increasing the water temperature in ocean currents and changes in sea levels. We emphasize the importance of the correlation of the water physico-chemical characteristics in these changes perceived in the studied environment. Greenland is defined by convention as the widest oceanic island in the world. In its fjords formed in the last glaciation of the Quaternary period, basically made of ice mountains with entries to the sea, there has been melts that are discussed in this work. At first, global warming and the melting of glaciers with a consequent rise in sea levels are presented almost as an axiom. This paper seeks to address the conclusions arising from this type of research according the basic laws of physics and chemistry, related to the behavior of water in their states (typically solid and liquid). The ultimate goal of this work glimpsed through some inferences and validation of water behavior in the ice condition and in its liquid state, a broader view with regard to the findings applied to the relationship between global warming and ice melting processes. Will be observed some water anomalies in the variation between its liquid and solid states to attempt a better understanding of the phenomena occurring in this area of interest as well as their possible impacts. It is noteworthy the fact that the water does not behave thermally as most liquids, with very specific consequences in relation to the variation between its

  16. Macrofaunal response to phytodetritus in a bathyal Norwegian fjord

    NASA Astrophysics Data System (ADS)

    Sweetman, Andrew K.; Witte, Ursula

    2008-11-01

    The continental margin (rise and shelf) constitutes approximately 1/10th of the surface area of the oceans, but 80-90% of all sedimentary organic matter (OM) is remineralised here. Recent evidence has suggested that macrofauna may play an important role in organic matter remineralisation in deep-sea continental margin sediments, and the deep fjords of western Norway provide a relatively easily accessible opportunity for detailed studies of continental margin macrofaunal communities and their role in C-cycling. We examined the macrofaunal community and assessed its response to a simulated OM pulse in a fjord environment using pulse-chase tracer experiments. In each experiment, 1 g C org m -2 of 13C-labelled Skeletonema costatum was deposited onto intact sediment cores collected from 688 m water depth and incubated ex situ for 2, 7 and 14 d. Macrofaunal abundance and biomass were comparable to those of other deep-sea continental margin sediments of similar depths, but in contrast to previous fjord studies, the macrofaunal community was numerically dominated by ostracods. Tracer experiments revealed highest uptake of tracer after 7 and 14 d compared to 2 d. Of the seven deposit feeding polychaete families, only the Paraonidae and Cirratulidae—together with the largely carnivorous Lumbrineridae—showed a significant response to our labelled C-source. The lack of response by the majority of deposit feeders and the unexpected feeding mode of the Lumbrineridae may be attributable to species—rather than family specific feeding—ecologies or ontogenetic changes in diet/feeding mode. Total macrofaunal C-turnover was much lower than recorded in the deep Sognefjord in a 3 d feeding experiment, and is possibly a result of (1) distinct differences in macrofaunal community composition between sites, with a predominantly sub-surface-feeding macrofaunal assemblage being found in this study as opposed to a surface-feeding community in the Sognefjord, or (2) variations in OM

  17. Effects of the March 1964 Alaska earthquake on glaciers: Chapter D in The Alaska earthquake, March 27, 1964: effects on hydrologic regimen

    USGS Publications Warehouse

    Post, Austin

    1967-01-01

    The 1964 Alaska earthquake occurred in a region where there are many hundreds of glaciers, large and small. Aerial photographic investigations indicate that no snow and ice avalanches of large size occurred on glaciers despite the violent shaking. Rockslide avalanches extended onto the glaciers in many localities, seven very large ones occurring in the Copper River region 160 kilometers east of the epicenter. Some of these avalanches traveled several kilometers at low gradients; compressed air may have provided a lubricating layer. If long-term changes in glaciers due to tectonic changes in altitude and slope occur, they will probably be very small. No evidence of large-scale dynamic response of any glacier to earthquake shaking or avalanche loading was found in either the Chugach or Kenai Mountains 16 months after the 1964 earthquake, nor was there any evidence of surges (rapid advances) as postulated by the Earthquake-Advance Theory of Tarr and Martin.

  18. The trans-Alaska pipeline controversy: Technology, conservation, and the frontier

    SciTech Connect

    Coates, P.A.

    1991-01-01

    The Trans-Alaska Pipeline was the object of perhaps the most passionately fought conservation battle in the U.S. Although numerous authors documented the pipeline construction during its construction, there is, surprisingly, no previous scholarly treatment of this event written by an historian. Coates is an environmental historian who views the most interesting aspect of the controversy to be [open quote]its relationship to earlier engineering projects and technological innovations in Alaska and the debates that accompanied them.[close quotes] Thus, he describes how the conservationist and environmental ideas arose during numerous earlier major Alaskan projects and controversies, including the Alaska Highway (1938-41), Canol Pipeline (1943-45), exploration of Naval Petroleum Reserve Number Four (Pet 4, 1944-1953), DEWline (1953-57), oil development in the Kenai National Moose Range (1957-58), statehood (1958), the creation of the Arctic Wildlife Refuge (1960), Project Chariot (1958-63), and Rampart Dam (1959-67). The history starts with the acquisition of Alaska in 1867 and finishes about the time of the Valdez oil spill in 1989.

  19. A genetic discontinuity in moose (Alces alces) in Alaska corresponds with fenced transportation infrastructure

    USGS Publications Warehouse

    Wilson, Robert E.; Farley, Sean D.; McDonough, Thomas J.; Talbot, Sandra L.; Barboza, Perry S.

    2015-01-01

    The strength and arrangement of movement barriers can impact the connectivity among habitat patches. Anthropogenic barriers (e.g. roads) are a source of habitat fragmentation that can disrupt these resource networks and can have an influence on the spatial genetic structure of populations. Using microsatellite data, we evaluated whether observed genetic structure of moose (Alces alces) populations were associated with human activities (e.g. roads) in the urban habitat of Anchorage and rural habitat on the Kenai Peninsula, Alaska. We found evidence of a recent genetic subdivision among moose in Anchorage that corresponds to a major highway and associated infrastructure. This subdivision is most likely due to restrictions in gene flow due to alterations to the highway (e.g. moose-resistant fencing with one-way gates) and a significant increase in traffic volume over the past 30 years; genetic subdivision was not detected on the Kenai Peninsula in an area not bisected by a major highway. This study illustrates that anthropogenic barriers can substructure wildlife populations within a few generations and highlights the value of genetic assessments to determine the effects on connectivity among habitat patches in conjunction with behavioral and ecological data..

  20. Massive submarine slope failures during the 1964 earthquake in Port Valdez, Alaska

    USGS Publications Warehouse

    Lee, H.; Ryan, H.F.; Suleimani, E.; Kayen, R.E.; Hampton, M.A.

    2006-01-01

    The M9.2 Alaska earthquake of 1964caused major damage to the port facilities and town of Valdez, resulting in a total of 32 deaths. Most of the damage and deaths in Valdez were caused by submarine-landslide generated tsunamis that occurred immediately after the earthquake. Some post-earthquake investigations were conducted in the 1960's. Dramatic changes in bathymetry were observed, including several hundred meters of deepening below the head of Port Valdezfjord, and these were attributed to submarine landsliding. Recent multibeam surveys of Port Valdez provide much more information about the morphology of landslide deposits. Also, we collected high-resolution (chirp) surveys over apparent landslide debris to evaluate the chronology and three-dimensional character of the deposits, and we performed quantitative evaluations of pre- and post-earthquake bathymetric data. Landslide morphologies include several forms. In the western part of the fjord, there is a field of large blocks (up to 40-m high) on the fjord floor near the location of the greatest tsunami-wave runup estimated for the 1964 earthquake (~50 m). The runup direction for the waves (northeast) is consistent with the failure of these blocks being the trigger. Surrounding the fields of blocks are lobes from two debris flows that likely occurred at the same time as the block slides. Both debris flows and block slides appear to have resulted from the failure of a large moraine front, formed by Shoup Glacier on the northwest side of Port Valdez. At the fjord head, near the location of the badly damaged old town of Valdez, is an intricate series of gullies, channels, and talus, although these features display little evidence for the large-scale mass movement that occurred. However, near the center of the fjord is the front of a large debris lobe that flowed from the east end of the fjord half-way down the fjord and stopped. This huge deposit represents material that failed at the fjord head

  1. The impact of glacier geometry on meltwater plume structure and submarine melt in Greenland fjords

    NASA Astrophysics Data System (ADS)

    Carroll, D.; Sutherland, D. A.; Hudson, B.; Moon, T.; Catania, G. A.; Shroyer, E. L.; Nash, J. D.; Bartholomaus, T. C.; Felikson, D.; Stearns, L. A.; Noël, B. P. Y.; Broeke, M. R.

    2016-09-01

    Meltwater from the Greenland Ice Sheet often drains subglacially into fjords, driving upwelling plumes at glacier termini. Ocean models and observations of submarine termini suggest that plumes enhance melt and undercutting, leading to calving and potential glacier destabilization. Here we systematically evaluate how simulated plume structure and submarine melt during summer months depends on realistic ranges of subglacial discharge, glacier depth, and ocean stratification from 12 Greenland fjords. Our results show that grounding line depth is a strong control on plume-induced submarine melt: deep glaciers produce warm, salty subsurface plumes that undercut termini, and shallow glaciers produce cold, fresh surface-trapped plumes that can overcut termini. Due to sustained upwelling velocities, plumes in cold, shallow fjords can induce equivalent depth-averaged melt rates compared to warm, deep fjords. These results detail a direct ocean-ice feedback that can affect the Greenland Ice Sheet.

  2. The lively Aysén fjord, Chile: Records of multiple geological processes

    NASA Astrophysics Data System (ADS)

    Lastras, Galderic; Amblas, David; Calafat, Antoni; Canals, Miquel; Frigola, Jaime; Hermanns, Reginald L.; Lafuerza, Sara; Longva, Oddvar; Micallef, Aaron; Sepúlveda, Sergio A.; Vargas, Gabriel; Azpiroz, María; Bascuñán, Ignacio; Duhart, Paul; Iglesias, Olaia; Kempf, Philipp; Rayo, Xavier

    2014-05-01

    The Aysén fjord is a 65 km long, east-west oriented fjord in Chilean Patagonia, located approximately at 45.4ºS and 73.2ºW, with a maximum water depth of 345 m. The fjord receives at present the riverine input of Aysén, Pescado, Condor and Cuervo rivers, which drain the surrounding up to 2000 m high Patagonian Andes. The fjord is crossed by a number of faults associated to the seismically active Liquiñe-Ofqui Fault Zone, a major trench parallel intra-arc fault system. After a four-month period of moderate seismicity, an Mw 6.2 earthquake on 21 April 2007 triggered dozens of subaerial landslides along the fjord flanks. Some of the landslides reached the fjord water mass, generating a series of tsunami-like displacement waves that impacted the adjacent coastlines with 3-12 m, locally over 50 m high run-ups, causing ten fatalities and severe damage to salmon farms. The research cruise DETSUFA on board BIO Hespérides in March 2013 mapped the submerged morphology of the fjord and gathered air-gun seismic profiles and sediment gravity cores in order to characterise the footprint of the landslides in the fjord floor. Very-high resolution multibeam bathymetry (4 m cell size) clearly shows the deformation structures created by the landslides in the inner fjord. The landslides descended and accelerated down the submerged fjord flanks, and reached the fjord floor at approx. 200 m water depth generating large, 1 to 10 m deep impact depressions. Sediment removed from these depressions moved radially and piled up in deformation rings formed by compressional ridges 10-15 m in height, block fields and a narrow frontal depression. Up to six >1.5 square km of these structures can be identified in the fjord. In addition, the DETSUFA survey extended beyond the SE-NW-oriented inner fjord past the Cuervo Ridge, located in front of the Cuervo river delta. The ridge, previously interpreted as a volcanic transverse structure, has most probably acted as a limit for grounding ice in

  3. High-frequency turbidity currents in British Columbia fjords

    NASA Astrophysics Data System (ADS)

    Bornhold, Brian D.; Ren, Ping; Prior, David B.

    1994-12-01

    The frequency of turbidity currents in Bute Inlet and Knight Inlet (British Columbia, Canada) was monitored. A prototype instrument (turbidity event detector) was deployed adjacent to prominent incised sea-floor channels. Approximately 25 30 turbidity currents occur annually. They appear closely correlated to periods of higher river discharge into the heads of the fjords. Two peaks in both discharge and turbidity current fequency occur, one in response to snow melt in late June early July, the other to glacier melt in August. Virtually no turbidity currents were observed in winter. River mouth bars, channel deposits, and other deltaic sediments build up during lower discharge periods and are swept onto the steep delta front and into subaqueous channels, along with bedload, during floods.

  4. Northern Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Seasonal ice in the Beaufort Sea off Alaska's North Slope has begun its spring retreat. This true color MODIS image from March 18, 2002, shows the pack ice in the Chuckchi Sea (left) and Beaufort Sea (top) backing away from its winter position snug up against Alaska's coasts, beginning its retreat into the Arctic Ocean. While not as pronounced in the Beaufort and Chukchi Seas as other part of the Arctic, scientists studying Arctic sea ice over the course of the century have documented dramatic changes in the extent of Arctic sea ice. It retreats farther in the summer and does not advance as far in the winter than it did a half-century ago. Both global warming and natural variation in regional weather systems have been proposed as causes. Along the coastal plain of the North Slope, gray-brown tracks (see high-resolution image) hint at melting rivers. South of the North Slope, the rugged mountains of the Brooks Range make a coast-to-coast arc across the state. Coming in at the lower right of the image, the Yukon River traces a frozen white path westward across half the image before veering south and out of view. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  5. Double-diffusive layering and mixing in Patagonian fjords

    NASA Astrophysics Data System (ADS)

    Pérez-Santos, Iván; Garcés-Vargas, José; Schneider, Wolfgang; Ross, Lauren; Parra, Sabrina; Valle-Levinson, Arnoldo

    2014-12-01

    Double-diffusive layering was quantified for the first time in the Chilean Patagonian fjords region (41.5-56°S). Approximately 600 temperature and salinity profiles collected during 1995-2012 were used to study water masses, quantify diffusive layering and compute the vertical diffusivity of heat. Development of 'diffusive-layering' or simply 'layering' was favored by relatively fresh-cold waters overlying salty-warm waters. Fresh waters are frequently derived from glacial melting that influences the fjord either directly or through rivers. Salty waters are associated with Modified Subantarctic (MSAAW) and Subantarctic Water (SAAW). Double-diffusive convection occurred as layering in 40% of the year-round data and as salt fingering in <1% of the time. The most vigorous layering, was found at depths between 20 and 70 m, as quantified by (a) Turner angles, (b) density ratios, and (c) heat diffusivity (with maximum values of 5 × 10-5 m2 s-1). Diffusive-layering events presented a meridional gradient with less layering within the 41-47°S northern region, relative to the southern region between 47° and 56°S. Layering occupied, on average, 27% and 56% of the water column in the northern and southern regions, respectively. Thermohaline staircases were detected with microprofile measurements in Martinez and Baker channels (48°S), showing homogeneous layers (2-4 m thick) below the pycnocline (10-40 m). Also in this area, increased vertical mixing coincided with the increased layering events. High values of Thorpe scale (LT ∼ 7 m), dissipation rate of TKE (ε = 10-5-10-3 W kg-1) and diapycnal eddy diffusivity (Kρ = 10-6-10-3 m-2 s-1) were associated with diffusive layering. Implications of these results are that diffusive layering should be taken into account, together with other mixing processes such as shear instabilities and wind-driven flows, in biological and geochemical studies.

  6. Seasonal variability of methyl iodide in the Kiel Fjord

    NASA Astrophysics Data System (ADS)

    Shi, Qiang; Petrick, Gert; Quack, Birgit; Marandino, Christa; Wallace, Douglas

    2014-03-01

    From October 2008 to November 2010, CH3I concentrations were measured in the Kiel Fjord together with potentially related biogeochemical and physical parameters. A repeating seasonal cycle of CH3I was observed with highest concentrations in summer (ca. 8.3 pmol L-1; June and July) and lowest concentrations in winter (ca. 1.5 pmol L-1; December to February). A strong positive correlation at zero lag between [CH3I] and solar radiation (R2 = 0.93) was observed, whereas correlations with other variables (SST, Chlorophyll a) were weaker, and they lagged CH3I by ca. 1 month. These results appear consistent with the hypothesis that SSR is the primary forcing of CH3I production in surface seawater, possibly through a photochemical pathway. A mass balance of the monthly averaged data was used to infer mean rates of daily net production (Pnet) and losses for CH3I over the year. The sea-to-air flux of CH3I in the Kiel Fjord averaged 3.1 nmol m-2 d-1, the mean chemical loss rate was 0.047 pmol L-1 d-1, and Pnet varied systematically from winter to summer (from 0 to 0.6 pmol L-1 d-1). Pnet was correlated at zero lag with SST, SSR, and Chla (R2 = 0.55, 0.67, and 0.73, respectively, p << 0.01). The lagged cross-correlation analysis indicated that SSR led Pnet by 1 month, whereas the strongest cross correlations with Chla were at lags of 0 to +1 month, and SST lagged Pnet by 1 month. The broad seasonal peak of Pnet makes it difficult to determine the key factor controlling CH3I net production using in situ concentration data alone.

  7. Macrobenthic biomass and production in a heterogenic subarctic fjord after invasion by the red king crab

    NASA Astrophysics Data System (ADS)

    Fuhrmann, Mona M.; Pedersen, Torstein; Ramasco, Virginie; Nilssen, Einar M.

    2015-12-01

    We studied the macrobenthic fauna and their production potential in Porsangerfjord, Northern Norway, in relation to environmental gradients and the recent invasion by the predatory red king crab into the outer fjord. The study area is characterized by a distinct along-fjord temperature gradient, with the influence of warmer Atlantic water in the outer fjord and year-round bottom temperatures around zero in the inner fjord. Benthic organisms can play a crucial role in ecosystem energy flow. Despite this, our knowledge of factors regulating benthic secondary production in high latitude ecosystems is limited. Macrobenthic abundance, biomass (B), production (P) and production-to-biomass ratio (P/B) were estimated from grab samples collected in 2010. Annual P/B ratios were calculated using a multi-parameter artificial neural network (ANN) model by Brey (2012). The mean abundance, biomass, production and P/B were 4611 ind. m- 2 (95% CI = 3994, 5316), 65 g ww m- 2 (95% CI = 51, 82), 174 kJ m- 2 y- 1 (95% CI = 151, 201) and 1.02 y- 1, respectively. Benthic biomass and production in the fjord were dominated by polychaetes. Spatial variability in P/B and production was mainly driven by community structure and differences in environmental habitat conditions. The inner basins of the fjord were characterized by high total production (439 kJ m- 2 y- 1), attributable to high standing stock biomass and community structure, despite cold bottom temperatures. In the middle and outer fjord, smaller taxa with low individual body masses increased the P/B ratios, but they did not compensate for the low biomass, thereby resulting in lower total production in these areas. The low biomass and the sparseness of large taxa in the outer and middle fjord may already be a result of predation by the invasive red king crab resulting in an overall lower macrobenthic production regime.

  8. Residency time, migration route and survival of Atlantic salmon Salmo salar smolts in a Canadian fjord.

    PubMed

    Dempson, J B; Robertson, M J; Pennell, C J; Furey, G; Bloom, M; Shears, M; Ollerhead, L M N; Clarke, K D; Hinks, R; Robertson, G J

    2011-06-01

    Atlantic salmon Salmo salar smolts (n = 181) from two rivers were surgically implanted with acoustic transmitters and released to determine migration route, residency time and survival in a 50 km long estuarine fjord located on the south coast of Newfoundland, Canada. Data obtained from automated receivers placed throughout the Bay d'Espoir fjord indicated that migrating smolts used different routes to reach the outer areas of the fjord. The duration of time that smolts spent in the immediate estuary zone also differed between the two localities (7 and 17 days) although the total time smolts were resident in the fjord was similar and extensive (40 days). Many smolts were resident for periods of 4-8 weeks moving back and forth in the outer part of the fjord where maximum water depths range from 300 to 700 m. Survival in the estuary zone was greater for smolts with prolonged residency in estuarine habitat. Overall smolt survival to the fjord exit was moderately high (54-85%), indicating that the initial phase of migration did not coincide with a period of unusually high mortality. PMID:21651545

  9. Monitoring fjord circulation using iceberg-mounted GPS as real-time drifters

    NASA Astrophysics Data System (ADS)

    Roth, G.; Sutherland, D.; Hamilton, G. S.; Stearns, L. A.

    2013-12-01

    The circulation in Greenland's large glacial fjords is one mechanism that controls the rate of submarine melting at the face of the Greenland Ice Sheet's outlet glaciers. Ship-board or moored instrumentation used to describe this circulation requires a ship presence and cannot safely be deployed in the ice mélange. At the same time, tracking and predicting the paths of individual icebergs, especially at finer time resolutions than remote sensing imagery can provide, remains a logistical challenge. Here we use real-time, hourly position data from disposable GPS units deployed by helicopter on five large (~500 meter) icebergs in Sermilik Fjord, SE Greenland. We observe and quantify the motions of these icebergs moving independently through the mélange, fjord, and shelf regimes. In the mélange, the icebergs remain stationary, until pushed loose by a series of calving events. In the fjord, high frequency, low amplitude tidally-driven motions are superimposed on 1-5 day events with net along-fjord velocities exceeding 0.1 m/s. We interpret these large-scale events as resulting from a two-layer, baroclinic flow driven by winds along the shelf. These results showcase the potential of this novel instrumentation to observe and link iceberg movements with circulation in any large glacial fjord.

  10. Using Icebergs to Constrain Fjord Circulation and Link to Glacier Dynamics

    NASA Astrophysics Data System (ADS)

    Sutherland, D.; Straneo, F.; Hamilton, G. S.; Stearns, L. A.; Roth, G.

    2014-12-01

    The importance of icebergs is increasingly being recognized in the ocean-glacier interactions community. Icebergs are ubiquitous in Greenland's outlet glacial fjords and provide a physical link between the glacier and the ocean into which they melt. The iceberg shape is influenced by glacier size and calving mechanics, while the amount of melt produced depends on ambient water properties and the residence time of the iceberg in the fjord. Here, we use hourly positions of icebergs tracked with helicopter deployed GPS sensors to calculate velocities in the Sermilik Fjord/Helheim Glacier system. Data comes from three summertime deployments in 2012-2014, where icebergs were tagged in the ice mélange and moved through the fjord and onto the continental shelf. The iceberg-derived velocities provide information on ice mélange movement, fjord variability, and coastal currents on the shelf. Using simple melt rate parameterizations, we estimate the total freshwater input due to iceberg melt in Sermilik Fjord based on the observed residence times and satellite-derived iceberg distributions. These observations complement conventional oceanographic and glaciological data, and can quickly, and relatively inexpensively, characterize circulation throughout any given glacier-ocean system.

  11. Novel Measurements and Techniques for Outlet Glacier Fjord Ice/Ocean Interactions

    NASA Astrophysics Data System (ADS)

    Behar, A.; Howat, I. M.; Holland, D. M.; Ahlstrom, A. P.; Larsen, S. H.

    2014-12-01

    Glacier fjord bathymetry and conditions indicate that they play fundamental roles for outlet glacier dynamics and thus knowledge of these parameters is extremely beneficial to upcoming models that predict changes. In particular, the bathymetry of a fjord gives important information about the exchange between fjord waters close to marine-terminating glaciers and the shelf and ocean. Currently, only sparse bathymetric data near the ice fronts are available for the majority of fjords in Greenland. The challenge in obtaining these measurements is that the fjord melange environment is a terrible one for mechanical gear, or ship or any other kind of access. There is hope however, and this work focuses on novel ways of obtaining this data using a multitude of upcoming technologies and techniques that are now being tested and planned. The span of the techniques described include but are not limited to: 1) manned helicopter-based live-reading instruments and deployable/retriavable sensor packages http://www.motionterra.com/fjord/ 2) remote or autonomous unmanned miniature boats (Depth/CTD), and 3) UAV's that either read live data or deploy small sensors that can telemeter their data (ice-flow trackers, image acquisition, etc.). A review of current results obtained at Jakobshavn and Upernavik Glaciers will be given as well as a description of the techniques and hardware used.

  12. 76 FR 6117 - Kenai Peninsula-Anchorage Borough Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-03

    ... will meet in Portage Valley, Alaska. The committee is meeting as authorized under the Secure Rural... sessions. Dated: January 26, 2011. Tim Charnon, District Ranger, Glacier Ranger District. BILLING CODE...

  13. A deglacial and Holocene record of climate variability in south-central Alaska from stable oxygen isotopes and plant macrofossils in peat

    USGS Publications Warehouse

    Jones, Miriam C.; Wooller, Matthew J.; Peteet, Dorothy M.

    2014-01-01

    We used stable oxygen isotopes derived from bulk peat (δ18OTOM), in conjunction with plant macrofossils and previously published carbon accumulation records, in a ∼14,500 cal yr BP peat core (HT Fen) from the Kenai lowlands in south-central Alaska to reconstruct the climate history of the area. We find that patterns are broadly consistent with those from lacustrine records across the region, and agree with the interpretation that major shifts in δ18OTOM values indicate changes in strength and position of the Aleutian Low (AL), a semi-permanent low-pressure cell that delivers winter moisture to the region. We find decreased strength or a more westerly position of the AL (relatively higher δ18OTOM values) during the Bølling-Allerød, Holocene Thermal Maximum (HTM), and late Holocene, which also correspond to warmer climate regimes. These intervals coincide with greater peat preservation and enhanced carbon (C) accumulation rates at the HT Fen and with peatland expansion across Alaska. The HTM in particular may have experienced greater summer precipitation as a result of an enhanced Pacific subtropical high, a pattern consistent with modern δ18O values for summer precipitation. The combined warm summer temperatures and greater summer precipitation helped promote the observed rapid peat accumulation. A strengthened AL (relatively lower δ18OTOM values) is most evident during the Younger Dryas, Neoglaciation, and the Little Ice Age, consistent with lower peat preservation and C accumulation at the HT Fen, suggesting less precipitation reaches the leeward side of the Kenai Mountains during periods of enhanced AL strength. The peatlands on the Kenai Peninsula thrive when the AL is weak and the contribution of summer precipitation is higher, highlighting the importance of precipitation seasonality in promoting peat accumulation. This study demonstrates that δ18OTOM values in peat can be applied toward understand large-scale shifts in atmospheric circulation

  14. Variations in Southeast Greenland fjord and coastal waters and their impact on glacier dynamics

    NASA Astrophysics Data System (ADS)

    Scharrer, K.; Duijkers, M.; Murray, T.; Booth, A.; Selmes, N.; James, T. D.; Bevan, S. L.; Luckman, A. J.

    2009-12-01

    The southeast quadrant of the Greenland ice sheet has undergone rapid changes in recent years and many marine-terminating outlet glaciers synchronously accelerated, thinned and their calving fronts retreated significantly between 2003 and 2005. Subsequently these glaciers have slowed, again simultaneously, with many outlets in 2008 flowing at speeds close to or even slower than in 2000/1. These dynamic changes seem to be triggered at the calving fronts of the glaciers, with changes in fjord water composition acting as the first order control. However, little is known about ocean-glacier interactions, especially about the processes and changes in the glacier-fjord-coastal ocean system in southeast (SE) Greenland. In order to investigate recent changes in outlet glacier dynamics in SE Greenland in the context of variations in fjord and ocean circulation, we analysed detailed time series of high-resolution satellite-derived sea surface temperature (SST) datasets for the period 2000 to 2009. In order to link these surface data to processes deeper in the water column we conducted a field campaign in Sermilik Fjord (Helheim glacier) during summer 2009. Coastal circulation patterns were investigated using the weekly SST product from the MODIS (MODerate Resolution Imaging Spectroradiometer) imagery, which provides coverage at 4 km spatial resolution with an accuracy of +/- 0.25 degrees Celsius. In addition, we used the 60 m resolution thermal band of Landsat-7 imagery to identify seasonal and annual temperature variations of coast and fjord waters at higher resolution. Temporal sequences of Landsat derived SST images were analysed at 6 locations along the SE Greenland coast. We also produced maps of bathymetry, and the temperature-depth and salinity-depth structure of Sermilik Fjord. Our data confirm that the speedup of SE Greenland outlet glaciers coincides with a decline of the cold East Greenland Coastal Current (EGCC), which was accompanied by the incursion of warm and

  15. Magnetic susceptibilities measured on rocks of the upper Cook Inlet, Alaska

    USGS Publications Warehouse

    Alstatt, A.A.; Saltus, R.W.; Bruhn, R.L.; Haeussler, P.J.

    2002-01-01

    We have measured magnetic susceptibility in the field on most of the geologic rock formations exposed in the upper Cook Inlet near Anchorage and Kenai, Alaska. Measured susceptibilities range from less than our detection limit of 0.01 x 10-3 (SI) to greater than 100 x 10-3 (SI). As expected, mafic igneous rocks have the highest susceptibilities and some sedimentary rocks the lowest. Rocks of the Tertiary Sterling Formation yielded some moderate to high susceptibility values. Although we do not have detailed information on the magnetic mineralogy of the rocks measured here, the higher susceptibilities are sufficient to explain the magnitudes of some short-wavelength aeromagnetic anomalies observed on recent surveys of the upper Cook Inlet.

  16. The presence of rapidly degrading permafrost plateaus in southcentral Alaska

    USGS Publications Warehouse

    Jones, Benjamin M.; Baughman, Carson; Romanovsky, V.adimir E; Parsekian, Andrew D.; Babcock, Esther; Jones, Miriam C.; Grosse, Guido; Berg, Edward E

    2016-01-01

    Permafrost presence is determined by a complex interaction of climatic, topographic, and ecological conditions operating over long time scales. In particular, vegetation and organic layer characteristics may act to protect permafrost in regions with a mean annual air temperature (MAAT) above 0°C. In this study, we document the presence of residual permafrost plateaus on the western Kenai Peninsula lowlands of southcentral Alaska, a region with a MAAT of 1.5 ± 1°C (1981 to 2010). Continuous ground temperature measurements between 16 September 2012 and 15 September 2015, using calibrated thermistor strings, documented the presence of warm permafrost (−0.04 to −0.08°C). Field measurements (probing) on several plateau features during the fall of 2015 showed that the depth to the permafrost table averaged 1.48 m but was as shallow as 0.53 m. Late winter surveys (drilling, coring, and GPR) in 2016 showed that the average seasonally frozen ground thickness was 0.45 m, overlying a talik above the permafrost table. Measured permafrost thickness ranged from 0.33 to >6.90 m. Manual interpretation of historic aerial photography acquired in 1950 indicates that residual permafrost plateaus covered 920 ha as mapped across portions of four wetland complexes encompassing 4810 ha. However, between 1950 and ca. 2010, permafrost plateau extent decreased by 60%, with lateral feature degradation accounting for 85% of the reduction in area. Permafrost loss on the Kenai Peninsula is likely associated with a warming climate, wildfires that remove the protective forest and organic layer cover, groundwater flow at depth, and lateral heat transfer from wetland surface waters in the summer. Better understanding the resilience and vulnerability of ecosystem-protected permafrost is critical for mapping and predicting future permafrost extent and degradation across all permafrost regions that are currently warming. Further work should focus on reconstructing permafrost history in

  17. Preliminary earthquake locations in the Kenai Peninsula recorded by the MOOS Array and their relationship to structure in the 1964 great earthquake zone

    NASA Astrophysics Data System (ADS)

    Li, J.; Abers, G. A.; Christensen, D. H.; Kim, Y.; Calkins, J. A.

    2011-12-01

    Earthquakes in subduction zones are mostly generated at the interface between the subducting and overlying plates. In 2006-2009, the MOOS (Multidisciplinary Observations Of Subduction) seismic array was deployed around the Kenai Peninsula, Alaska, consisting of 34 broadband seismometers recording for 1-3 years. This region spans the eastern end of the Aleutian megathrust that ruptured in the 1964 Mw 9.2 great earthquake, the second largest recorded earthquake, and ongoing seismicity is abundant. Here, we report an initial analysis of seismicity recorded by MOOS, in the context of preliminary imaging. There were 16,462 events detected in one year from initial STA/LTA signal detections and subsequent event associations from the MOOS Array. We manually reviewed them to eliminate distant earthquakes and noise, leaving 11,879 local earthquakes. To refine this catalog, an adaptive auto-regressive onset estimation algorithm was applied, doubling the original dataset and producing 20,659 P picks and 22,999 S picks for one month (September 2007). Inspection shows that this approach lead to almost negligible false alarms and many more events than hand picking. Within the well-sampled part of the array, roughly 200 km by 300 km, we locate 250% more earthquakes for one month than the permanent network catalog, or 10 earthquakes per day on this patch of the megathrust. Although the preliminary locations of earthquakes still show some scatter, we can see a concentration of events in a ~20-km-wide belt, part of which can be interpreted as seismogenic thrust zone. In conjunction with the seismicity study, we are imaging the plate interface with receiver functions. The main seismicity zone corresponds to the top of a low-velocity layer imaged in receiver functions, nominally attributed to the top of the downgoing plate. As we refine velocity models and apply relative relocation algorithms, we expect to improve the precision of the locations substantially. When combined with image

  18. Crustal Uplift in the Southcentral Alaska Subduction Zones: A New Analysis and Interpretation of Tide Gauge Observations

    NASA Technical Reports Server (NTRS)

    Cohen, Steven C.; Freymueller, Jeffrey T.

    1999-01-01

    We have examined the sea level height tide records at seven tide gauge sites in the region of southcentral Alaska that were affected by the 1964 Prince William Sound earthquake to determine the history of crustal uplift subsequent to the earthquake. There is considerable variation in the behavior depending on the location of the site relative to the 1964 rupture. At Seward, on the eastern side of the Kenai Peninsula we find a slow uplift that is consistent with elastic strain accumulation while at Seldovia and Nikiski on the western side of the Kenai we find a persistent rapid uplift of about 1 cm/yr that most likely represents a long term transient response to the earthquake, but which cannot be sustained over the expected recurrence interval for a great earthquake of several hundred years. Further to the southwest, at Kodiak, we find evidence that the rate of uplift, which is still several mm/yr, has slowed significantly over the past three and a half decades. To the east of the Kenai Peninsula we find subsidence at Cordova and an uncertain behavior at Valdez. At both of these sites there is a mathematically significant time-dependence to the uplift behavior, but the data confirming this time dependence are not as convincing as at Kodiak. At Anchorage, to the north there is little evidence of vertical motion since the earthquake. We compare these long term tide gauge records to recent GPS observations. In general there is reasonable consistency except at Anchorage and Cordova where the GPS measurement indicate somewhat more rapid uplift and subsidence, respectively.

  19. Environmental and human influences on trumpeter swan habitat occupancy in Alaska

    USGS Publications Warehouse

    Schmidt, J.H.; Lindberg, M.S.; Johnson, D.S.; Schmultz, J.A.

    2009-01-01

    Approximately 70-80% of the entire population of the Trumpeter Swan (Cygnus huccinator) depends for reproduction on wetlands in Alaska. This makes the identification of important habitat features and the effects of human interactions important for the species' long-term management. We analyzed the swan's habitat preferences in five areas throughout the state and found that swan broods occupied some wetland types, especially larger closed-basin wetlands such as lakes and ponds, at rates much higher than they occupied other wetland types, such as shrubby or forested wetlands. We also found a negative effect of transportation infrastructure on occupancy by broods in and around the Minto Flats State Game Refuge, Kenai National Wildlife Refuge, and Tetlin National Wildlife Refuge. This finding is of particular interest because much of the Minto Flats refuge has recently been licensed for oil and gas exploration and parts of the Kenai refuge have been developed in the past. We also investigated the potential effects of the shrinkage of closed-basin ponds on habitat occupancy by nesting Trumpeter Swans. We compared nesting swans' use of ponds with changes in the ponds' size and other characteristics from 1982 to 1996 and found no relationships between occupancy and changes in pond size. However, we believe that the recent and rapid growth of Trumpeter Swan populations in Alaska may become limited by available breeding habitat, and anthropogenic and climate-induced changes to the swan's breeding habitats have the potential to limit future production. ?? 2009 by The Cooper Ornithological Society. All rights reserved.

  20. Role of lake regulation on glacier-fed rivers in enhancing salmon productivity: the Cook Inlet watershed, south-central Alaska, USA

    NASA Astrophysics Data System (ADS)

    Dorava, Joseph M.; Milner, Alexander M.

    2000-10-01

    Rivers fed by glaciers constitute a major part of the freshwater runoff into the Cook Inlet basin of south-central Alaska. This basin is very important to the economy of the State of Alaska because it is home to more than half of the population and it supports multi-million dollar commercial, subsistence and sport fisheries. Hence an understanding of how glacial runoff influences biological productivity is important for managing rivers that drain into Cook Inlet. This paper examines the ways in which the regulation of glacier-fed rivers by proglacial lakes affects salmon productivity, with particular reference to the Kenai River. Salmon escapement per unit channel length on the Kenai River is between two and ten times that found for rain-and-snowmelt dominated rivers and glacier-fed rivers lacking lake regulation.Lakes are shown to influence biological processes in glacier-fed rivers by attenuating peak flows, sustaining high flows throughout the summer, supplementing winter low flows, settling suspended sediment, and increasing river temperatures. Downstream from large lakes, glacier-fed rivers are less disturbed, channels are relatively stable and have well-developed salmonid habitats. The positive influences are indicated by the high diversity and abundances of benthic macroinvertebrates, which are important food resources for juvenile salmonids. High summer flows allow access for up-river salmon runs and lakes also provide both overwintering and rearing habitat.

  1. Geologic framework of lower Cook Inlet, Alaska

    USGS Publications Warehouse

    Fisher, M.A.; Magoon, L.B.

    1978-01-01

    Three seismic reflectors are present throughout the lower Cook Inlet basin and can be correlated with onshore geologic features. The reflections come from unconformities at the base of the Tertiary sequence, at the base of Upper Cretaceous rocks, and near the base of Upper Jurassic strata. A contour map of the deepest horizon shows that Mesozoic rocks are formed into a northeast-trending syncline. Along the southeast flank of the basin, the northwest-dipping Mesozoic rocks are truncated at the base of Tertiary rocks. The Augustine-Seldovia arch trends across the basin axis between Augustine Island and Seldovia. Tertiary rocks thin onto the arch from the north and south. Numerous anticlines, smaller in structural relief and breadth than the Augustine-Seldovia arch, trend northeast parallel with the basin, and intersect the arch at oblique angles. The stratigraphic record shows four cycles of sedimentation and tectonism that are bounded by three regional unconformities in lower Cook Inlet and by four thrust faults and the modern Benioff zone in flysch rocks of the Kenai Peninsula and the Gulf of Alaska. The four cycles of sedimentation are, from oldest to youngest, the early Mesozoic, late Mesozoic, early Cenozoic, and late Cenozoic. Data on organic geochemistry of the rocks from one well suggest that Middle Jurassic strata may be a source of hydrocarbons. Seismic data show that structural traps are formed by northeast-trending anticlines and by structures formed at the intersections of these anticlines with the transbasin arch. Stratigraphic traps may be formed beneath the unconformity at the base of Tertiary strata and beneath unconformities within Mesozoic strata.

  2. Seasonality of vertical flux and sinking particle characteristics in an ice-free high arctic fjord-Different from subarctic fjords?

    NASA Astrophysics Data System (ADS)

    Wiedmann, Ingrid; Reigstad, Marit; Marquardt, Miriam; Vader, Anna; Gabrielsen, Tove M.

    2016-02-01

    The arctic Adventfjorden (78°N, 15°E, Svalbard) used to be seasonally ice-covered but has mostly been ice-free since 2007. We used this ice-free arctic fjord as a model area to investigate (1) how the vertical flux of biomass (chlorophyll a and particulate organic carbon, POC) follows the seasonality of suspended material, (2) how sinking particle characteristics change seasonally and affect the vertical flux, and (3) if the vertical flux in the ice-free arctic fjord with glacial runoff resembles the flux in subarctic ice-free fjords. During seven field investigations (December 2011-September 2012), suspended biomass was determined (5, 15, 25, and 60 m), and short-term sediment traps were deployed (20, 30, 40, and 60 m), partly modified with gel-filled jars to study the size and frequency distribution of sinking particles. During winter, resuspension from the seafloor resulted in large, detrital sinking particles. Intense sedimentation of fresh biomass occurred during the spring bloom. The highest POC flux was found during autumn (770-1530 mg POC m- 2 d- 1), associated with sediment-loaded glacial runoff and high pteropod abundances. The vertical biomass flux in the ice-free arctic Adventfjorden thus resembled that in subarctic fjords during winter and spring, but a higher POC sedimentation was observed during autumn.

  3. Alaska's Children, 1997.

    ERIC Educational Resources Information Center

    Douglas, Dorothy, Ed.

    1997-01-01

    These four issues of the "Alaska's Children" provide information on the activities of the Alaska Head Start State Collaboration Project and other Head Start activities. Legal and policy changes affecting the education of young children in Alaska are also discussed. The Spring 1997 issue includes articles on brain development and the "I Am Your…

  4. Alaska's Economy: What's Ahead?

    ERIC Educational Resources Information Center

    Alaska Review of Social and Economic Conditions, 1987

    1987-01-01

    This review describes Alaska's economic boom of the early 1980s, the current recession, and economic projections for the 1990s. Alaska's economy is largely influenced by oil prices, since petroleum revenues make up 80% of the state government's unrestricted general fund revenues. Expansive state spending was responsible for most of Alaska's…

  5. Alaska Natives & the Land.

    ERIC Educational Resources Information Center

    Arnold, Robert D.; And Others

    Pursuant to the Native land claims within Alaska, this compilation of background data and interpretive materials relevant to a fair resolution of the Alaska Native problem seeks to record data and information on the Native peoples; the land and resources of Alaska and their uses by the people in the past and present; land ownership; and future…

  6. Alaska Women: A Databook.

    ERIC Educational Resources Information Center

    White, Karen; Baker, Barbara

    This data book uses survey and census information to record social and economic changes of the past three decades and their effects upon the role of Alaska women in society. Results show Alaska women comprise 47% of the state population, an increase of 9% since 1950. Marriage continues as the predominant living arrangement for Alaska women,…

  7. Marine fungi isolated from Chilean fjord sediments can degrade oxytetracycline.

    PubMed

    Ahumada-Rudolph, R; Novoa, V; Sáez, K; Martínez, M; Rudolph, A; Torres-Diaz, C; Becerra, J

    2016-08-01

    Salmon farming is the main economic activity in the fjords area of Southern Chile. This activity requires the use of antibiotics, such as oxytetracycline, for the control and prevention of diseases, which have a negative impact on the environment. We analyzed the abilities of endemic marine fungi to biodegrade oxytetracycline, an antibiotic used extensively in fish farming. We isolated marine fungi strains from sediment samples obtained from an area of fish farming activity. The five isolated strains showed an activity on oxytetracycline and were identified as Trichoderma harzianum, Trichoderma deliquescens, Penicillium crustosum, Rhodotorula mucilaginosa, and Talaromyces atroroseus by a scanning electron microscopy and characterized by molecular techniques. Results showed significant degradation in the concentration of oxytetracycline at the first 2 days of treatment for all strains analyzed. At 21 days of treatment, the concentration of oxytetracycline was decreased 92 % by T. harzianum, 85 % by T. deliquescens, 83 % by P. crustosum, 73 % by R. mucilaginosa, and 72 % by T. atroroseus, all of which were significantly higher than the controls. Given these results, we propose that fungal strains isolated from marine sediments may be useful tools for biodegradation of antibiotics, such as oxytetracycline, in the salmon industry. PMID:27418075

  8. Marine fungi isolated from Chilean fjord sediments can degrade oxytetracycline.

    PubMed

    Ahumada-Rudolph, R; Novoa, V; Sáez, K; Martínez, M; Rudolph, A; Torres-Diaz, C; Becerra, J

    2016-08-01

    Salmon farming is the main economic activity in the fjords area of Southern Chile. This activity requires the use of antibiotics, such as oxytetracycline, for the control and prevention of diseases, which have a negative impact on the environment. We analyzed the abilities of endemic marine fungi to biodegrade oxytetracycline, an antibiotic used extensively in fish farming. We isolated marine fungi strains from sediment samples obtained from an area of fish farming activity. The five isolated strains showed an activity on oxytetracycline and were identified as Trichoderma harzianum, Trichoderma deliquescens, Penicillium crustosum, Rhodotorula mucilaginosa, and Talaromyces atroroseus by a scanning electron microscopy and characterized by molecular techniques. Results showed significant degradation in the concentration of oxytetracycline at the first 2 days of treatment for all strains analyzed. At 21 days of treatment, the concentration of oxytetracycline was decreased 92 % by T. harzianum, 85 % by T. deliquescens, 83 % by P. crustosum, 73 % by R. mucilaginosa, and 72 % by T. atroroseus, all of which were significantly higher than the controls. Given these results, we propose that fungal strains isolated from marine sediments may be useful tools for biodegradation of antibiotics, such as oxytetracycline, in the salmon industry.

  9. Ground breakage and associated effects in the Cook Inlet area, Alaska, resulting from the March 27, 1964 earthquake: Chapter F in The Alaska earthquake, March 27, 1964: regional effects

    USGS Publications Warehouse

    Foster, Helen L.; Karlstrom, Thor N.V.

    1967-01-01

    The great 1964 Alaska earthquake caused considerable ground breakage in the Cook Inlet area of south-central Alaska. The breakage occurred largely in thick deposits of unconsolidated sediments. The most important types of ground breakage were (1) fracturing or cracking and the extrusion of sand and gravel with ground water along fractures in various types of landforms, and (2) slumping and lateral extension of unconfined faces, particularly along delta fronts. The principal concentration of ground breakage within the area covered by this report was in a northeast-trending zone about 60 miles long and 6 miles wide in the northern part of the Kenai Lowland. The zone cut across diverse topography and stratigraphy. Cracks were as much as 30 feet across and 25 feet deep. Sand, gravel, and pieces of coal and lignite were extruded along many fissures. It is suggested that the disruption in this zone may be due to movement along a fault in the underlying Tertiary rocks. The outwash deltas of Tustumena and Skilak Lakes in the Kenai Lowland, of Eklutna Lake and Lake George in the Chugach Mountains, of Bradley Lake in the Kenai Mountains, and at the outlet of upper Beluga Lake at the base of the Alaska Range showed much slumping, as did the delta of the Susitna River. Parts of the flood plains of the Skilak River, Fox River, and Eagle River were extensively cracked. A few avalanches and slumps occurred along the coast of Cook Inlet in scattered localities. Some tidal flats were cracked. However, in view of the many thick sections of unconsolidated sediments and the abundance of steep slopes, the cracking was perhaps less than might have been expected. Observations along the coasts indicated changes in sea level which, although caused partly by compaction of unconsolidated sediments, may largely be attributed to crus1tal deformation accompanying the earthquake. Most of the Cook Inlet area was downwarped, although the northwest side of Cook Inlet may have been slightly unwarped

  10. Shoreline impacts in the Gulf of Alaska region following the Exxon Valdez oil spill

    SciTech Connect

    Gilfillan, E.S.; Page, D.S.; Suchanek, T.H.; Boehm, P.D.; Harner, E.J.; Sloan, N.A.

    1995-12-31

    Forty-eight sites in the Gulf of Alaska region (GOA-Kodiak Island, Kenai Peninsula, and Alaska Peninsula) were sampled in July/August 1989 to assess the impact of the March 24, 1989, Exxon Valdez oil spill on shoreline chemistry and biological communities hundreds of miles from the spill origin. In a 1990 companion study, 5 of the Kensai sites and 13 of the Kodiak and Alaska Peninsula sites were sampled 16 months after the spill. Oiling levels at each site were estimated visually and/or quantified by chemical analysis. The chemical analyses were performed on sediment and/or rock wipe samples collected with the biological samples. Additional sediment samples were collected for laboratory amphipod toxicity tests. Mussels were also collected and analyzed for hydrocarbon content to assess hydrocarbon bioavailability. Biological investigations at these GOA sites focused on intertidal infauna, epifauna, and macroalgae by means of a variety of common ecological techniques. For rock sites the percentage of hard substratum covered by biota was quantified. At each site, up to 5 biological samples (scrapes of rock surfaces or sediment cores) were collected intertidally along each of 3 transects, spanning tide levels from the high intertidal to mean-lowest-low-water (zero tidal datum). Organisms (down to 1.0 mm in size) from these samples were sorted and identified. Community parameters including organism abundance, species richness, and Shannon diversity were calculated for each sample. 43 refs., 13 figs., 3 tabs.

  11. Hydrology-linked spatial distribution of pesticides in a fjord system in Greenland.

    PubMed

    Carlsson, Pernilla; Cornelissen, Gerard; Bøggild, Carl Egede; Rysgaard, Søren; Mortensen, John; Kallenborn, Roland

    2012-05-01

    A pilot study is presented evaluating selected chlorinated pesticides as chemical tracers for water masses in a sub-Arctic fjord system (Godthåbsfjord, western Greenland). Polyoxymethylene (POM) based passive water samplers were deployed during summer-autumn 2010. The levels of the analysed chlorinated pesticides in the fjord surface waters were found to be low compared to earlier studies. α-Hexachlorocyclohexane (α-HCH) and hexachlorobenzene (HCB) were the predominant contaminants. However, these two compounds have higher levels in oceanic water compared to freshwater influenced fjord waters. These chemicals can thus be considered as indicators for direct atmospheric long-range transport, while the organochlorine pesticides like trans-, cis-chlordane, trans-nonachlor and oxychlordane that are detected in the inner parts of the fjord are indicators for potential freshwater sources such as rivers and glacial meltwater runoff (secondary sources). The average values were 50 pg L(-1) for HCB and 11 pg L(-1) for α-HCH. These concentrations are comparable to levels in fjords in Svalbard (Norwegian Arctic), but lower than in open and/or ice covered oceans in the Canadian Arctic. Two air samplers were deployed for the identification of direct atmospheric contributions. Local contamination sources do not contribute significantly. The study demonstrated the value of passive water sampling devices for comprehensive hydrological characterization of Arctic coastal waters.

  12. Hydrology-linked spatial distribution of pesticides in a fjord system in Greenland.

    PubMed

    Carlsson, Pernilla; Cornelissen, Gerard; Bøggild, Carl Egede; Rysgaard, Søren; Mortensen, John; Kallenborn, Roland

    2012-05-01

    A pilot study is presented evaluating selected chlorinated pesticides as chemical tracers for water masses in a sub-Arctic fjord system (Godthåbsfjord, western Greenland). Polyoxymethylene (POM) based passive water samplers were deployed during summer-autumn 2010. The levels of the analysed chlorinated pesticides in the fjord surface waters were found to be low compared to earlier studies. α-Hexachlorocyclohexane (α-HCH) and hexachlorobenzene (HCB) were the predominant contaminants. However, these two compounds have higher levels in oceanic water compared to freshwater influenced fjord waters. These chemicals can thus be considered as indicators for direct atmospheric long-range transport, while the organochlorine pesticides like trans-, cis-chlordane, trans-nonachlor and oxychlordane that are detected in the inner parts of the fjord are indicators for potential freshwater sources such as rivers and glacial meltwater runoff (secondary sources). The average values were 50 pg L(-1) for HCB and 11 pg L(-1) for α-HCH. These concentrations are comparable to levels in fjords in Svalbard (Norwegian Arctic), but lower than in open and/or ice covered oceans in the Canadian Arctic. Two air samplers were deployed for the identification of direct atmospheric contributions. Local contamination sources do not contribute significantly. The study demonstrated the value of passive water sampling devices for comprehensive hydrological characterization of Arctic coastal waters. PMID:22481207

  13. Compaction and movement of interstitial water in bottom sediments of the Saguenay Fjord, Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Leclerc, A.; Gagnon, M. J.; Côté, R.; Rami, A.

    1986-02-01

    Eight sediment cores were collected along the length of the Saguenay Fjord and Baie des Ha! Ha!, Québec, Canada. Profiles of the sediment water contents were determined for each core. Porosities were fitted to an exponential relation with core depth. The relation was modified to account for variations in granulometry and in organic carbon contents of the sediments. Porosities were observed to be more sensitive to variations in organic content than to variations in granulometry, and grain sorting appeared more important than grain size. Grain-size distribution of the sediments is in agreement with a sedimentation model where most of the suspended load enters the fjord from the Saguenay River and is deposited downstream with the surface current. The coarse particles are mainly found close to the head of the fjord, whereas the fine particles are carried farther downstream. Surface porosities were observed to be proportional to the sedimentation fluxes obtained from the literature whereas the compaction showed an inverse relationship. The fractional decreases in porosity due to compaction along the fjord indicate some horizontal flow of the interstitial water at both ends of the sampled part of the fjord. An average vertical interstitial pore water flow of 0.4 cm yr -1 with respect to the surface horizon is estimated from the data. This is small compared with the diffusion of the major constituents of sea water through the sediment.

  14. Status and distribution of the Kittlitz's Murrelet Brachyramphus brevirostris along the Alaska Peninsula and Kodiak and Aleutian Islands, Alaska

    USGS Publications Warehouse

    Madison, Erica N.; Piatt, John F.; Arimitsu, Mayumi L.; Romano, Marc D.; van Pelt, Thomas I.; Nelson, S. Kim; Williams, Jeffrey C.; DeGange, Anthony R.

    2011-01-01

    The Kittlitz's Murrelet Brachyramphus brevirostris is adapted for life in glacial-marine ecosystems, being concentrated in the belt of glaciated fjords in the northern Gulf of Alaska from Glacier Bay to Cook Inlet. Most of the remaining birds are scattered along coasts of the Alaska Peninsula and Aleutian Islands, where they reside in protected bays and inlets, often in proximity to remnant glaciers or recently deglaciated landscapes. We summarize existing information on Kittlitz's Murrelet in this mainly unglaciated region, extending from Kodiak Island in the east to the Near Islands in the west. From recent surveys, we estimated that ~2400 Kittlitz's Murrelets were found in several large embayments along the Alaska Peninsula, where adjacent ice fields feed silt-laden water into the bays. On Kodiak Island, where only remnants of ice remain today, observations of Kittlitz's Murrelets at sea were uncommon. The species has been observed historically around the entire Kodiak Archipelago, however, and dozens of nest sites were found in recent years. We found Kittlitz's Murrelets at only a few islands in the Aleutian chain, notably those with long complex shorelines, high mountains and remnant glaciers. The largest population (~1600 birds) of Kittlitz's Murrelet outside the Gulf of Alaska was found at Unalaska Island, which also supports the greatest concentration of glacial ice in the Aleutian Islands. Significant populations were found at Atka (~1100 birds), Attu (~800) and Adak (~200) islands. Smaller numbers have been reported from Unimak, Umnak, Amlia, Kanaga, Tanaga, Kiska islands, and Agattu Island, where dozens of nest sites have been located in recent years. Most of those islands have not been thoroughly surveyed, and significant pockets of Kittlitz's Murrelets may yet be discovered. Our estimate of ~6000 Kittlitz's Murrelets along the Alaska Peninsula and Aleutian Islands is also likely to be conservative because of the survey protocols we employed (i.e. early

  15. Modelling the impact of variations in ice sheet runoff on fjord and coastal biological productivity over annual to decadal timescales

    NASA Astrophysics Data System (ADS)

    Sole, A. J.; Cowton, T. R.

    2015-12-01

    Each summer, vast quantities of surface-derived ice sheet meltwater runs off from the Greenland Ice Sheet. Much of this runoff is injected into glaciated fjords at depth beneath marine-terminating glaciers. Due to its low relative density, the runoff rises as a buoyant plume up the glaciers' calving fronts, entraining deep fjord water as it does so. This deep, ambient water tends to be relatively rich in nutrients and so the runoff plumes act to fertilise the surface layers of the fjord, leading to an observed late season spike in biological productivity in the fjord's surface layers. Although surface melting and runoff from the Greenland Ice Sheet are predicted to increase significantly in the coming years and decades, the potential effect of this on fjord and coastal biological productivity is yet to be quantified. Here we present simulations of fjord circulation and biological productivity using the Massachusetts Institute of Technology general circulation model (MITgcm), and a new coupled representation of buoyant runoff plumes which enables decadal time period experiments of large three dimensional fjords. We investigate the effect on biological productivity of varying ice sheet runoff, ocean properties, near-surface winds and fjord geometry and bathymetry. We find that variations in ice sheet runoff are particularly important for biological productivity because the rate of discharge controls the depth at which the plumes reach neutral buoyancy and therefore whether the nutrient-rich deep water is delivered to the photic zone.

  16. Spring bloom dynamics in a subarctic fjord influenced by tidewater outlet glaciers (Godthåbsfjord, SW Greenland)

    NASA Astrophysics Data System (ADS)

    Meire, Lorenz; Mortensen, John; Rysgaard, Søren; Bendtsen, Jørgen; Boone, Wieter; Meire, Patrick; Meysman, Filip J. R.

    2016-06-01

    In high-latitude fjord ecosystems, the spring bloom accounts for a major part of the annual primary production and thus provides a crucial energy supply to the marine food web. However, the environmental factors that control the timing and intensity of these spring blooms remain uncertain. In 2013, we studied the spring bloom dynamics in Godthåbsfjord, a large fjord system adjacent to the Greenland Ice Sheet. Our surveys revealed that the spring bloom did not initiate in the inner stratified part of the fjord system but only started farther away from tidewater outlet glaciers. A combination of out-fjord winds and coastal inflows drove an upwelling in the inner part of the fjord during spring (April-May), which supplied nutrient-rich water to the surface layer. This surface water was subsequently transported out-fjord, and due to this circulation regime, the biomass accumulation of phytoplankton was displaced away from the glaciers. In late May, the upwelling weakened and the dominant wind direction changed, thus reversing the direction of the surface water transport. Warmer water was now transported toward the inner fjord, and a bloom was observed close to the glacier terminus. Overall, our findings imply that the timing, intensity, and location of the spring blooms in Godthåbsfjord are controlled by a combination of upwelling strength and wind forcing. Together with sea ice cover, the hydrodynamic regime hence plays a crucial role in structuring food web dynamics of the fjord ecosystem.

  17. Landslides Cause Tsunami Waves: Insights From Aysén Fjord, Chile

    NASA Astrophysics Data System (ADS)

    Lastras, Galderic; Amblas, David; Calafat, Antoni M.; Canals, Miquel; Frigola, Jaime; Hermanns, Reginald L.; Lafuerza, Sara; Longva, Oddvar; Micallef, Aaron; Sepúlveda, Sergio A.; Vargas, Gabriel; Batist, Marc De; Daele, Maarten Van; Azpiroz, María.; Bascuñán, Ignacio; Duhart, Paul; Iglesias, Olaia; Kempf, Philipp; Rayo, Xavier

    2013-08-01

    On 21 April 2007, an Mw 6.2 earthquake produced an unforeseen chain of events in the Aysén fjord (Chilean Patagonia, 45.5°S). The earthquake triggered hundreds of subaerial landslides along the fjord flanks. Some of the landslides eventually involved a subaqueous component that, in turn, generated a series of displacement waves—tsunami-like waves produced by the fast entry of a subaerial landmass into a water body—within the fjord [Naranjo et al., 2009; Sepúlveda and Serey, 2009; Hermanns et al., 2013]. These waves, with run-ups several meters high along the shoreline, caused 10 fatalities. In addition, they severely damaged salmon farms, which constitute the main economic activity in the region, setting free millions of cultivated salmon with still unknown ecological consequences.

  18. An experiment with forced oxygenation of the deepwater of the anoxic By Fjord, western Sweden.

    PubMed

    Stigebrandt, Anders; Liljebladh, Bengt; de Brabandere, Loreto; Forth, Michael; Granmo, Åke; Hall, Per; Hammar, Jonatan; Hansson, Daniel; Kononets, Mikhail; Magnusson, Marina; Norén, Fredrik; Rahm, Lars; Treusch, Alexander H; Viktorsson, Lena

    2015-02-01

    In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment.

  19. Trophic position of Calanus finmarchicus (Copepoda, Calanoida) in the Trondheim Fjord

    NASA Astrophysics Data System (ADS)

    Saage, A.; Altin, D.; Vadstein, O.; Sommer, U.

    2008-04-01

    The trophic position of Calanus finmarchicus in the Trondheim Fjord in 2004 was determined through stable isotope analyses. Wild specimens were sampled monthly in the fjord and δ 13C and δ 15N signatures of the developmental stages from CIII to adults were measured. There were statistically significant differences in the δ 13C and δ 15N signatures of three identified groups: overwintered parental generation, developing new generation and new generation preparing for overwintering. C. finmarchicus individuals raised in a laboratory on a pure algal diet ( Dunaliella tertiolecta and Isochrysis galbana) provided stable isotope signatures for purely herbivorous copepods. With these signatures as comparison, the trophic position of C. finmarchicus in the Trondheim Fjord in 2004 was determined as trophic level 2.4, thus indicating omnivory under natural conditions. Additionally, our data suggest that seasonal differences in the δ 13C signatures of C. finmarchicus are due to the varying lipid content of the different developmental stages.

  20. Atlantic water in Svalbard fjords: variability and effects on local sea ice cover

    NASA Astrophysics Data System (ADS)

    Sundfjord, Arild; Albretsen, Jon; Kasajima, Yoshie; Prominska, Agnieszka; Nilsen, Frank; Beszczynska-Möller, Agnieszka; Muckenhuber, Stefan; Isaksen, Ketil; Cottier, Finlo; Gerland, Sebasitan; Kohler, Jack

    2016-04-01

    Atlantic Water entering the Arctic fjords of western Svalbard transport large amounts of heat, sufficient to influence the local sea ice cover as well as contributing to glacier front melting. Recent measurement campaigns, including moorings and high-resolution surveys, spanning years with very different Atlantic Water inflow, were conducted in two fjords with different characteristics; Hornsund and Kongsfjorden. The data collected reveal a strong coupling between ocean-fjord exchanges and local sea ice cover. Possible triggering mechanisms for exchange events such as wind episodes, internal waves, and density differences are explored. Results from fine-resolution coupled ocean-sea ice model simulations complement the analysis of Atlantic Water exchange mechanisms and allow us to quantify the extent to which glacial runoff forces local circulation.

  1. The Climatology and Impacts of Atmospheric Rivers near the Coast of Southern Alaska

    NASA Astrophysics Data System (ADS)

    Nardi, K.; Barnes, E. A.; Mundhenk, B. D.

    2015-12-01

    Atmospheric rivers, narrow plumes of anomalously high tropospheric water vapor transport, frequently appear over the Pacific Ocean. Popularized by colloquialisms such as the "Pineapple Express," atmospheric rivers often interact with synoptic-scale disturbances to produce significant precipitation events over land masses. Previous research has focused extensively on the impacts of this phenomenon with respect to high-precipitation storms, namely during boreal winter, on the western coast of the contiguous United States. These events generate great scientific, political, and economic concerns for nearby cities, farms, and tourist destinations. Recently, researchers have investigated similar high-precipitation events along the southern coast of Alaska. Specifically, previous work has discussed several major events occurring during the September-November timeframe. One particular event, in October 2006, produced an all-time record for water levels at several river observation sites. This study examines the climatology of atmospheric rivers in the vicinity of southern Alaska. Data (1979-2014) from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) is used to detect atmospheric rivers approaching, and making landfall on, the southern Alaskan coast from the Kenai Peninsula to the Gulf of Alaska region. A seasonal cycle in the strength and frequency of atmospheric rivers over Alaska is shown. Furthermore, the study assesses the synoptic conditions coincident with atmospheric rivers and examines several instances of particularly strong precipitation events. For example, wintertime atmospheric river events tend to occur when a blocking high exists over southeastern Alaska. These results have the potential to help forecasters and emergency managers predict high-precipitation events and lessen potential negative impacts.

  2. Heat and Ice in Sermilik Fjord: Novel Observational Techniques Using PIES

    NASA Astrophysics Data System (ADS)

    Andres, M.; Straneo, F.; Sutherland, D.

    2014-12-01

    A 1-year pilot experiment using pressure-sensor-equipped inverted echo sounders (PIES) was conducted in Sermilik Fjord in eastern Greenland to test non-traditional methods for measuring the time-varying
heat content in high-latitude seas, shelves, and fjords and for detecting the presence of ice. PIES, which are installed on the seafloor below the reach of destructive iceberg keels, present
a promising and inexpensive way to improve understanding of fjord dynamics and shelf-fjord interactions and will increase long-term monitoring capabilities in high latitudes where
remoteness and harsh conditions hamper traditional in situ observation techniques. The use
of PIES to characterize variability at high latitudes is a novel application of an existing
technology, but rests on the same principle as the traditional blue-water uses for PIES: due
to the dependence of sound speed on temperature, the surface-to-bottom round-trip acoustic-travel-time associated with reflections between the PIES and the air-sea interface is an excellent proxy
for heat content in the intervening water column. Furthermore, since reflections from seawater-ice interfaces are also detected when ice
is present, PIES provide a means to characterize the ice component in high-latitude systems. The PIES deployed in Sermilik Fjord (August 2011 - September 2012) resolved changes in heat content at scales ranging from hourly to seasonal. Furthermore, during winter, the PIES logged about 300 iceberg detections and recorded a 2-week period of land-fast ice cover in March. The deepest icebergs in the fjord were found to have keel depths reaching to ~350 m and iceberg speeds averaged about 0.2 m/s but were as high as 0.5 m/s.

  3. Observed Spatial and Temporal Variability of Subglacial Discharge-Driven Plumes in Greenland's Outlet Glacial Fjords

    NASA Astrophysics Data System (ADS)

    Sutherland, D.; Carroll, D.; Nash, J. D.; Shroyer, E.; Mickett, J.; Stearns, L. A.; Fried, M.; Bartholomaus, T.; Catania, G. A.

    2015-12-01

    Hydrographic and velocity observations in Greenland's outlet glacier fjords have revealed, unsurprisingly, a rich set of dynamics over a range of spatial and temporal scales. Through teasing apart the distinct processes that control circulation within these fjords, we are likely to better understand the impact of fjord circulation on modulating outlet glacier dynamics, and thus, changes in Greenland Ice Sheet mass balance. Here, we report on data from the summers of 2013-2015 in two neighboring fjords in the Uummannaq Bay region of west Greenland: Kangerlussuup Sermia (KS) and Rink Isbræ (RI). We find strong subglacial discharge driven plumes in both systems that evolve on synoptic and seasonal time scales, without the complicating presence of other circulation processes. The plumes both modify fjord water properties and respond to differences in ambient water properties, supporting the notion that a feedback exists between subglacial discharge plume circulation and water mass properties. This feedback between subglacial discharge and water properties potentially influences submarine melt rates at the glacier termini. Observed plume properties, including the vertical structure of velocity, and temperature and salinity anomalies, are compared favorably to model estimates. In KS, we find a near-surface intensified plume with high sediment content that slows and widens as it evolves downstream. In contrast, the plume in RI is entirely subsurface, ranging from 100-300 m depth at its core during summer, although it shows similar temperature, salinity, and optical backscatter signals to the KS plume. Importantly, the distinct vertical plume structures imprint on the overall water mass properties found in each fjord, raising the minimum temperatures by up to 1-2°C in the case of RI.

  4. Compared sub-bottom profile interpretation in fjords of King George Island and Danco Coast, Antarctica

    NASA Astrophysics Data System (ADS)

    Rodrigo, C.; Vilches, L.; Vallejos, C.; Fernandez, R.; Molares, R.

    2015-12-01

    The fjords of the South Shetland Islands (Antarctica) and Danco Coast (Antarctic Peninsula) represent climatic transitional areas (subpolar to polar). The analysis of the distribution of sub-bottom facies helps to understand the prevailing sedimentary and climatic processes. This work seeks to characterize and compare the fjord seismic facies, of the indicated areas, to determine the main sedimentary processes in these regions. Compressed High-Intensity Radiated Pulse (CHIRP) records from 3.5 kHz sub-bottom profiler were obtained from the cruise: NBP0703 (2007); and pinger 3.5 kHz sub-bottom profiler records from the cruises: ECA-50 INACH (2014), and First Colombian Expedition (2015). Several seismic facies were recognized in all studied areas with some variability on their thickness and extent, and indicate the occurrence of similar sedimentary processes. These are: SSD facies (strong to weak intensity, stratified, draped sheet external shape), is interpreted as sedimentary deposits originated from suspended sediments from glaciar plumes and/or ice-rafting. This facies, in general, is thicker in the fjords of King George Island than in the larger fjords of the Danco Coast; on the other hand, within the Danco Coast area, this facies is thinner and more scarce in the smaller fjords and bays. MCM facies (moderate intensity, chaotic and with mounds) is associated with moraine deposits and/or basement. This is present in all areas, being most abundant in the Danco Coast area. WIC facies (weak intensity and chaotic) is interpreted as debris flows, which are present in both regions, but is most common in small fjords or bays in the Danco Coast, perhaps due to higher slopes of the seabed. In this work we discuss the influence of local climate, sediment plumes from the glaciers and other sedimentary processes on the distribution and geometry of the identified seismic facies.

  5. Temporal Patterns of Protozooplankton Abundance and Their Food in Ellis Fjord, Princess Elizabeth Land, Eastern Antarctica

    NASA Astrophysics Data System (ADS)

    Grey, J.; Laybourn-Parry, J.; Leakey, R. J. G.; McMinn, A.

    1997-07-01

    The abundance and biomass of ciliates, dinoflagellates and heterotrophic and phototrophic nanoflagellates were determined at three sites along an ice-covered Antarctic fjord between January and November 1993. The water column showed little in the way of temperature and salinity gradients during the study period. In general, the protozooplankton exhibited a seasonal variation which closely mirrored that of chlorophyllaand bacterioplankton. The fjord mouth, which was affected by the greatest marine influences, consistently had the highest densities of ciliates and the most diverse community, with up to 18 species during the sampling period. Small aloricate ciliates were present throughout the year withStrobilidiumspp. being dominant during the winter. Larger loricate and aloricate ciliates became more prominent during January and November, along with the autotrophic ciliateMesodinium rubrumand two mixotrophic species (Strombidium wulffiand a type resemblingTontonia) suggesting evidence of species successions. Data on dinoflagellates were less extensive, but these protists showed greatest species diversity in the middle reaches of the fjord. A total of 13 species of dinoflagellate was recorded. Ciliates made a significant contribution to the biomass of the microbial community in summer, particularly in the middle and at the seaward end of the fjord. In winter, heterotrophic flagellates (HNAN) and phototrophic nanoflagellates (PNAN) were the dominant component of protistan biomass. In terms of percentage contribution to the microbial carbon pool, bacteria dominated during winter and spring. To the authors' knowledge, this is the first seasonal study of an Antarctic fjord. The Ellis Fjord is very unproductive compared to lower latitude systems, and supports low biomass of phytoplankton and microbial plankton during most of the year. This relates to severe climatic and seasonal conditions, and the lack of allochthonous carbon inputs to the system. Thus, high latitude

  6. Methane seeps along boundaries of receding glaciers in Alaska and Greenland

    NASA Astrophysics Data System (ADS)

    Walter Anthony, K. M.; Anthony, P. M.; Grosse, G.; Chanton, J.

    2012-12-01

    Glaciers, ice sheets, and permafrost form a 'cryosphere cap' that traps methane formed in the subsurface, restricting its flow to the Earth's surface and atmosphere. Despite model predictions that glacier melt and degradation of permafrost open conduits for methane's escape, there has been a paucity of field evidence for 'subcap' methane seepage to the atmosphere as a direct result of cryosphere disintegration in the terrestrial Arctic. Here, we document for the first time the release of sub-cryosphere methane to lakes, rivers, shallow marine fjords and the atmosphere from abundant gas seeps concentrated along boundaries of receding glaciers and permafrost thaw in Alaska and Greenland. Through aerial and ground surveys of 6,700 lakes and fjords in Alaska we mapped >150,000 gas seeps identified as bubbling-induced open holes in seasonal ice. Using gas flow rates, stable isotopes, and radiocarbon dating, we distinguished recent ecological methane from subcap, geologic methane. Subcap seeps had anomalously high bubbling rates, 14C-depletion, and stable isotope values matching microbial sources associated with sedimentary deposits and coal beds as well as thermogenic methane accumulations in Alaska. Since differential ice loading can overpressurize fluid reservoirs and cause sediment fracturing beneath ice sheets, and since the loss of glacial ice reduces normal stress on ground, opens joints, and activates faults and fissures, thereby increasing permeability of the crust to fluid flow, we hypothesized that in the previously glaciated region of Southcentral Alaska, where glacial wastage continues presently, subcap seeps should be disproportionately associated with neotectonic faults. Geospatial analysis confirmed that subcap seep sites were associated with faults within a 7 km belt from the modern glacial extent. The majority of seeps were located in areas affected by seismicity from isostatic rebound associated with deglaciation following the Little Ice Age (LIA; ca

  7. Benthic foraminiferal biogeography in NW European fjords: A baseline for assessing future change

    NASA Astrophysics Data System (ADS)

    Murray, John W.; Alve, Elisabeth

    2016-11-01

    The seaboard extending from northern Svalbard to Scotland is the only region of the world where fjords have been comprehensively studied for their live (stained) benthic foraminiferal faunas. These modern faunas provide essential baseline data for the interpretation of the postglacial and continuing environmental changes in those fjords and this is the first biogeographic synthesis. The data come from the surface sediment assemblages (mainly sampled in the 1990's) from all the available literature. Due to limited information of shallow water assemblages in the north, only the species occurrences in deeper water from below the halocline are considered. Amongst these, only "common species" species occurring in more than one fjord are included. There is a clear pattern of distribution with five groups of taxa: 5 widespread species found throughout the region; 53 species reaching their northern limit; 13 species reaching their southern limit; 11 deep-sea species; 1 recently introduced species. Although there is an abrupt change in temperature from Tanafjorden in northern Norway to Hornsund in southern Svalbard, the faunal change from N to S is progressive throughout the investigated region. The area of overlap of the northern and southern species corresponds with the previously recognised boundary between the Barents Sea Province and the Norwegian Coast Province based on shelf and upper slope invertebrate macrofaunal benthos and plankton. Temperature is the main abiotic control on the distributions. For the fjords which have shallow sills separating them from the open shelf it is likely that most of the foraminiferal colonisers of the deeper fjord basins are sourced from the shelf or slope via propagules. One species has recently been introduced from further south into the southern region probably through the discharge of ballast water from ships. The biodiversity of the pristine Svalbard fjords extends below what is considered to reflect acceptable ecological status

  8. Marine benthic habitat mapping of Muir Inlet, Glacier Bay National Park and Preserve, Alaska, with an evaluation of the Coastal and Marine Ecological Classification Standard III

    USGS Publications Warehouse

    Trusel, Luke D.; Cochrane, Guy R.; Etherington, Lisa L.; Powell, Ross D.; Mayer, Larry A.

    2010-01-01

    Seafloor geology and potential benthic habitats were mapped in Muir Inlet, Glacier Bay National Park and Preserve, Alaska, using multibeam sonar, ground-truth information, and geological interpretations. Muir Inlet is a recently deglaciated fjord that is under the influence of glacial and paraglacial marine processes. High glacially derived sediment and meltwater fluxes, slope instabilities, and variable bathymetry result in a highly dynamic estuarine environment and benthic ecosystem. We characterize the fjord seafloor and potential benthic habitats using the Coastal and Marine Ecological Classification Standard (CMECS) recently developed by the National Oceanic and Atmospheric Administration (NOAA) and NatureServe. Substrates within Muir Inlet are dominated by mud, derived from the high glacial debris flux. Water-column characteristics are derived from a combination of conductivity temperature depth (CTD) measurements and circulation-model results. We also present modern glaciomarine sediment accumulation data from quantitative differential bathymetry. These data show Muir Inlet is divided into two contrasting environments: a dynamic upper fjord and a relatively static lower fjord. The accompanying maps represent the first publicly available high-resolution bathymetric surveys of Muir Inlet. The results of these analyses serve as a test of the CMECS and as a baseline for continued mapping and correlations among seafloor substrate, benthic habitats, and glaciomarine processes.

  9. Particulate organic matter sinks and sources in high Arctic fjord

    NASA Astrophysics Data System (ADS)

    Kuliński, Karol; Kędra, Monika; Legeżyńska, Joanna; Gluchowska, Marta; Zaborska, Agata

    2014-11-01

    The main aim of this paper is to present results on concentrations, fluxes and isotopic composition (δ13Corg) of particulate and sedimentary organic carbon (measures of particulate and sedimentary organic matter, respectively) in Kongsfjorden, Spitsbergen. The terrestrial particulate organic carbon (POC) input to the Kongsfjorden reached 760 · 106 ± 145 · 106 g Corg y- 1, forced mostly by the glaciers' activity. This constituted 5-10% of the bulk POC supplied to the system. Marine primary production was the main source of the remaining 90-95% of POC. Organic carbon burial rates amounted to 9 ± 1 g Corg m- 2 y- 1 in the central and 13 ± 1 g Corg m- 2 y- 1 in the outer part of the fjord. Two terrestrial POM δ13Corg end members were identified: the ancient organic matter (OM) supplied by glaciers and rivers fed by water discharged from the glaciers (from - 25.4‰ to - 25.1‰), and the fresh terrestrial POM (from - 26.7‰ to - 26.6‰). Marine OM was characterized by a wide range of δ13Corg signatures: from ≤ - 26.1‰ for the phytoplankton depleted in 13Corg to ca. - 15.8‰ for debris of marine phytobenthos. The lack of distinct marine δ13Corg end member and the resemblance of phytoplankton δ13Corg signatures to the terrestrial POM δ13Corg end member precluded the use of the two δ13Corg end member mixing model to trace the terrestrial OM in Kongsfjorden, which is also very likely to happen in other Arctic regions.

  10. Preliminary volcano-hazard assessment for Augustine Volcano, Alaska

    USGS Publications Warehouse

    Waythomas, Christopher F.; Waitt, Richard B.

    1998-01-01

    Augustine Volcano is a 1250-meter high stratovolcano in southwestern Cook Inlet about 280 kilometers southwest of Anchorage and within about 300 kilometers of more than half of the population of Alaska. Explosive eruptions have occurred six times since the early 1800s (1812, 1883, 1935, 1964-65, 1976, and 1986). The 1976 and 1986 eruptions began with an initial series of vent-clearing explosions and high vertical plumes of volcanic ash followed by pyroclastic flows, surges, and lahars on the volcano flanks. Unlike some prehistoric eruptions, a summit edifice collapse and debris avalanche did not occur in 1812, 1935, 1964-65, 1976, or 1986. However, early in the 1883 eruption, a portion of the volcano summit broke loose forming a debris avalanche that flowed to the sea. The avalanche initiated a small tsunami reported on the Kenai Peninsula at English Bay, 90 kilometers east of the volcano. Plumes of volcanic ash are a major hazard to jet aircraft using Anchorage International and other local airports. Ashfall from future eruptions could disrupt oil and gas operations and shipping activities in Cook Inlet. Eruptions similar to the historical and prehistoric eruptions are likely in Augustine's future.

  11. Volcanic tsunamis and prehistoric cultural transitions in Cook Inlet, Alaska

    USGS Publications Warehouse

    Beget, J.; Gardner, C.; Davis, K.

    2008-01-01

    The 1883 eruption of Augustine Volcano produced a tsunami when a debris avalanche traveled into the waters of Cook Inlet. Older debris avalanches and coeval paleotsunami deposits from sites around Cook Inlet record several older volcanic tsunamis. A debris avalanche into the sea on the west side of Augustine Island ca. 450??years ago produced a wave that affected areas 17??m above high tide on Augustine Island. A large volcanic tsunami was generated by a debris avalanche on the east side of Augustine Island ca. 1600??yr BP, and affected areas more than 7??m above high tide at distances of 80??km from the volcano on the Kenai Peninsula. A tsunami deposit dated to ca. 3600??yr BP is tentatively correlated with a southward directed collapse of the summit of Redoubt Volcano, although little is known about the magnitude of the tsunami. The 1600??yr BP tsunami from Augustine Volcano occurred about the same time as the collapse of the well-developed Kachemak culture in the southern Cook Inlet area, suggesting a link between volcanic tsunamis and prehistoric cultural changes in this region of Alaska. ?? 2008 Elsevier B.V.

  12. A submarine landslide source for the devastating 1964 Chenega tsunami, southern Alaska

    NASA Astrophysics Data System (ADS)

    Brothers, Daniel S.; Haeussler, Peter J.; Liberty, Lee; Finlayson, David; Geist, Eric; Labay, Keith; Byerly, Mike

    2016-03-01

    During the 1964 Great Alaska earthquake (Mw 9.2), several fjords, straits, and bays throughout southern Alaska experienced significant tsunami runup of localized, but unexplained origin. Dangerous Passage is a glacimarine fjord in western Prince William Sound, which experienced a tsunami that devastated the village of Chenega where 23 of 75 inhabitants were lost - the highest relative loss of any community during the earthquake. Previous studies suggested the source of the devastating tsunami was either from a local submarine landslide of unknown origin or from coseismic tectonic displacement. Here we present new observations from high-resolution multibeam bathymetry and seismic reflection surveys conducted in the waters adjacent to the village of Chenega. The seabed morphology and substrate architecture reveal a large submarine landslide complex in water depths of 120-360 m. Analysis of bathymetric change between 1957 and 2014 indicates the upper 20-50 m (∼0.7 km3) of glacimarine sediment was destabilized and evacuated from the steep face of a submerged moraine and an adjacent ∼21 km2 perched sedimentary basin. Once mobilized, landslide debris poured over the steep, 130 m-high face of a deeper moraine and then blanketed the terminal basin (∼465 m water depth) in 11 ± 5 m of sediment. These results, combined with inverse tsunami travel-time modeling, suggest that earthquake-triggered submarine landslides generated the tsunami that struck the village of Chenega roughly 4 min after shaking began. Unlike other tsunamigenic landslides observed in and around Prince William Sound in 1964, the failures in Dangerous Passage are not linked to an active submarine delta. The requisite environmental conditions needed to generate large submarine landslides in glacimarine fjords around the world may be more common than previously thought.

  13. A submarine landslide source for the devastating 1964 Chenega tsunami, southern Alaska

    USGS Publications Warehouse

    Brothers, Daniel; Haeussler, Peter J.; Lee Liberty,; David Finlayson,; Geist, Eric L.; Labay, Keith; Michael Byerly,

    2016-01-01

    During the 1964 Great Alaska earthquake (Mw 9.2), several fjords, straits, and bays throughout southern Alaska experienced significant tsunami runup of localized, but unexplained origin. Dangerous Passage is a glacimarine fjord in western Prince William Sound, which experienced a tsunami that devastated the village of Chenega where 23 of 75 inhabitants were lost – the highest relative loss of any community during the earthquake. Previous studies suggested the source of the devastating tsunami was either from a local submarine landslide of unknown origin or from coseismic tectonic displacement. Here we present new observations from high-resolution multibeam bathymetry and seismic reflection surveys conducted in the waters adjacent to the village of Chenega. The seabed morphology and substrate architecture reveal a large submarine landslide complex in water depths of 120–360 m. Analysis of bathymetric change between 1957 and 2014 indicates the upper 20–50 m (∼0.7 km3) of glacimarine sediment was destabilized and evacuated from the steep face of a submerged moraine and an adjacent ∼21 km2 perched sedimentary basin. Once mobilized, landslide debris poured over the steep, 130 m-high face of a deeper moraine and then blanketed the terminal basin (∼465 m water depth) in 11 ± 5 m of sediment. These results, combined with inverse tsunami travel-time modeling, suggest that earthquake- triggered submarine landslides generated the tsunami that struck the village of Chenega roughly 4 min after shaking began. Unlike other tsunamigenic landslides observed in and around Prince William Sound in 1964, the failures in Dangerous Passage are not linked to an active submarine delta. The requisite environmental conditions needed to generate large submarine landslides in glacimarine fjords around the world may be more common than previously thought. 

  14. Alaska Volcano Observatory

    USGS Publications Warehouse

    Venezky, Dina Y.; Murray, Tom; Read, Cyrus

    2008-01-01

    Steam plume from the 2006 eruption of Augustine volcano in Cook Inlet, Alaska. Explosive ash-producing eruptions from Alaska's 40+ historically active volcanoes pose hazards to aviation, including commercial aircraft flying the busy North Pacific routes between North America and Asia. The Alaska Volcano Observatory (AVO) monitors these volcanoes to provide forecasts of eruptive activity. AVO is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO is one of five USGS Volcano Hazards Program observatories that monitor U.S. volcanoes for science and public safety. Learn more about Augustine volcano and AVO at http://www.avo.alaska.edu.

  15. Turbidity-current channels in Queen Inlet, Glacier Bay, Alaska

    USGS Publications Warehouse

    Carlson, P.R.; Powell, R.D.; Rearic, D.M.

    1989-01-01

    Queen Inlet is unique among Glacier Bay fjords because it alone has a branching channel system incised in the Holocene sediment fill of the fjord floor. Queen Inlet and other known channel-containing fjords are marine-outwash fjords; the tidewater glacial fjords do not have steep delta fronts on which slides are generated and may not have a sufficient reservoir of potentially unstable coarse sediment to generate channel-cutting turbidity currents. Presence or absence of channels, as revealed in the ancient rock record, may be one criterion for interpreting types of fjords. -Authors

  16. Role of lake regulation on glacier fed rivers in enhancing salmon productivity: The Cook Inlet watershed south central Alaska, USA

    USGS Publications Warehouse

    Hupp, C.R.

    2000-01-01

    Rivers fed by glaciers constitute a major part of the freshwater runoff into the Cook Inlet basin of south-central Alaska. This basin is very important to the economy of the State of Alaska because it is home to more than half of the population and it supports multi-million dollar commercial, subsistence and sport fisheries. Hence an understanding of how glacial runoff influences biological productivity is important for managing rivers that drain into Cook Inlet. This paper examines the ways in which the regulation of glacier-fed rivers by proglacial lakes affects salmon productivity, with particular reference to the Kenai River. Salmon escapement per unit channel length on the Kenai River is between two and ten times that found for rain-and-snowmelt dominated rivers and glacier-fed rivers lacking lake regulation. Lakes are shown to influence biological processes in glacier-fed rivers by attenuating peak flows, sustaining high flows throughout the summer, supplementing winter low flows, settling suspended sediment, and increasing river temperatures. Downstream from large lakes, glacier-fed rivers are less disturbed, channels are relatively stable and have well-developed salmonid habitats. The positive influences are indicated by the high diversity and abundances of benthic macroinvertebrates, which are important food resources for juvenile salmonids. High summer flows allow access for up-river salmon runs and lakes also provide both overwintering and rearing habitat. Copyright ?? 2000 John Wiley & Sons, Ltd.Rivers fed by glaciers constitute a major part of the freshwater runoff into the Cook Inlet basin of south-central Alaska. This basin is very important to the economy of the State of Alaska because it is home to more than half of the population and it supports multi-million dollar commercial, subsistence and sport fisheries. Hence an understanding of how glacial runoff influences biological productivity is important for managing rivers that drain into Cook Inlet

  17. Relatively high antibiotic resistance among heterotrophic bacteria from arctic fjord sediments than water - Evidence towards better selection pressure in the fjord sediments

    NASA Astrophysics Data System (ADS)

    Hatha, A. A. Mohamed; Neethu, C. S.; Nikhil, S. M.; Rahiman, K. M. Mujeeb; Krishnan, K. P.; Saramma, A. V.

    2015-12-01

    The objective of this study was to determine the prevalence of antibiotic resistance among aerobic heterotrophic bacteria and coliform bacteria from water and sediment of Kongsfjord. The study was based on the assumption that arctic fjord environments are relatively pristine and offer very little selection pressure for drug resistant mutants. In order to test the hypothesis, 200 isolates belonging to aerobic heterotrophic bacteria and 114 isolates belonging to coliforms were tested against 15 antibiotics belonging to 5 different classes such as beta lactams, aminoglycosides, quinolones, sulpha drugs and tetracyclines. Resistance to beta lactam and extended spectrum beta lactam (ESBL) antibiotics was considerably high and they found to vary significantly (p < 0.05) between heterotrophic and coliform bacteria. Though the coliforms showed significantly high level of antibiotic resistance against ESBL's extent and diversity of antibiotic resistance (as revealed by multiple antibiotic resistance index and resistance patterns), was high in the aerobic heterotrophic bacteria. Most striking observation was that isolates from fjord sediments (both heterotrophic bacteria and coliforms) in general showed relatively high prevalence of antibiotic resistance against most of the antibiotics tested, indicating to better selection pressure for drug resistance mutants in the fjord sediments.

  18. A synthesis of the ongoing seasonal work in a west Greenland tidewater outlet glacier fjord, Godthåbsfjord

    NASA Astrophysics Data System (ADS)

    Mortensen, J.; Bendtsen, J.; Rysgaard, S.

    2015-12-01

    The coastal waters off west Greenland is subjected to significant temperature fluctuations which might affect the mass loss from local tidewater outlet glaciers from the Greenland Ice Sheet in different ways. We present a comprehensive hydrographic data set from a west Greenland fjord, Godthåbsfjord, a fjord in contact with the Greenland Ice Sheet through tidewater outlet glaciers. We analyze with respect to water masses, dynamics, seasonal and interannual hydrographic variability. Through seasonal observations of hydrographic and moored observations we recognize a seasonal pattern in the fjords circulation system, where an intermediate baroclinic circulation mode driven by tidal currents at the fjord entrance is associated as an important local heat source for the fjord. Four distinct circulation modes are observed in the fjord of which all can contribute to glacial ice melt. In water observation of a subglacial plume core will be presented and discussed with respect to vertical distribution of water masses and local heat budget in the fjord. The example of the extreme case of subglacial plume will be discussed (ice-dammed lake drainage).

  19. Alaska's renewable energy potential.

    SciTech Connect

    Not Available

    2009-02-01

    This paper delivers a brief survey of renewable energy technologies applicable to Alaska's climate, latitude, geography, and geology. We first identify Alaska's natural renewable energy resources and which renewable energy technologies would be most productive. e survey the current state of renewable energy technologies and research efforts within the U.S. and, where appropriate, internationally. We also present information on the current state of Alaska's renewable energy assets, incentives, and commercial enterprises. Finally, we escribe places where research efforts at Sandia National Laboratories could assist the state of Alaska with its renewable energy technology investment efforts.

  20. Patagonian fjord ecosystems in southern Chile as a highly vulnerable region: problems and needs.

    PubMed

    Iriarte, Jose Luis; González, Humberto E; Nahuelhual, Laura

    2010-11-01

    Southern Chile encompasses one of the most extensive fjord regions of the world, the Patagonia, currently exposed to natural and anthropogenic perturbations. These fjord ecosystems provide important services to humans, which have not been adequately measured and valued. As a consequence, ecosystem services are commonly ignored in public policy design and in the evaluation of development projects. Here we tackle questions that are highly relevant for the nation's development, namely (1) understanding fjord functioning, and (2) developing management strategies based on ecosystem services, in order to secure simultaneous and adequate use of these ecosystems which area influenced by ecological (e.g., biogeochemical) and productive (e.g., aquaculture, fisheries) processes. We also seek to strengthen the analysis of fjord ecosystem value from the economical (including coastal zoning), socio-cultural, institutional, and governmental points of view. In addition, the investigation of current and future effects of climate change on this large region offers a unique opportunity to understand the social and economic consequences of a global phenomenon at local to regional scales. Biogeochemical and socio-economic models will be used to simulate future scenarios under a gamut of management options.

  1. Internal pressure gradient errors in σ-coordinate ocean models in high resolution fjord studies

    NASA Astrophysics Data System (ADS)

    Berntsen, Jarle; Thiem, Øyvind; Avlesen, Helge

    2015-08-01

    Terrain following ocean models are today applied in coastal areas and fjords where the topography may be very steep. Recent advances in high performance computing facilitate model studies with very high spatial resolution. In general, numerical discretization errors tend to zero with the grid size. However, in fjords and near the coast the slopes may be very steep, and the internal pressure gradient errors associated with σ-models may be significant even in high resolution studies. The internal pressure gradient errors are due to errors when estimating the density gradients in σ-models, and these errors are investigated for two idealized test cases and for the Hardanger fjord in Norway. The methods considered are the standard second order method and a recently proposed method that is balanced such that the density gradients are zero for the case ρ = ρ(z) where ρ is the density and z is the vertical coordinate. The results show that by using the balanced method, the errors may be reduced considerably also for slope parameters larger than the maximum suggested value of 0.2. For the Hardanger fjord case initialized with ρ = ρ(z) , the errors in the results produced with the balanced method are orders of magnitude smaller than the corresponding errors in the results produced with the second order method.

  2. Melting glacier impacts community structure of Bacteria, Archaea and Fungi in a Chilean Patagonia fjord.

    PubMed

    Gutiérrez, Marcelo H; Galand, Pierre E; Moffat, Carlos; Pantoja, Silvio

    2015-10-01

    Jorge Montt glacier, located in the Patagonian Ice Fields, has undergone an unprecedented retreat during the past century. To study the impact of the meltwater discharge on the microbial community of the downstream fjord, we targeted Bacteria, Archaea and Fungi communities during austral autumn and winter. Our results showed a singular microbial community present in cold and low salinity surface waters during autumn, when a thicker meltwater layer was observed. Meltwater bacterial sequences were related to Cyanobacteria, Proteobacteria, Actinobacteria and Bacteriodetes previously identified in freshwater and cold ecosystems, suggesting the occurrence of microorganisms adapted to live in the extreme conditions of meltwater. For Fungi, representative sequences related to terrestrial and airborne fungal taxa indicated transport of allochthonous Fungi by the meltwater discharge. In contrast, bottom fjord waters from autumn and winter showed representative Operational Taxonomic Units (OTUs) related to sequences of marine microorganisms, which is consistent with current models of fjord circulation. We conclude that meltwater can significantly modify the structure of microbial communities and support the development of a major fraction of microorganisms in surface waters of Patagonian fjords. PMID:25856307

  3. Melting glacier impacts community structure of Bacteria, Archaea and Fungi in a Chilean Patagonia fjord.

    PubMed

    Gutiérrez, Marcelo H; Galand, Pierre E; Moffat, Carlos; Pantoja, Silvio

    2015-10-01

    Jorge Montt glacier, located in the Patagonian Ice Fields, has undergone an unprecedented retreat during the past century. To study the impact of the meltwater discharge on the microbial community of the downstream fjord, we targeted Bacteria, Archaea and Fungi communities during austral autumn and winter. Our results showed a singular microbial community present in cold and low salinity surface waters during autumn, when a thicker meltwater layer was observed. Meltwater bacterial sequences were related to Cyanobacteria, Proteobacteria, Actinobacteria and Bacteriodetes previously identified in freshwater and cold ecosystems, suggesting the occurrence of microorganisms adapted to live in the extreme conditions of meltwater. For Fungi, representative sequences related to terrestrial and airborne fungal taxa indicated transport of allochthonous Fungi by the meltwater discharge. In contrast, bottom fjord waters from autumn and winter showed representative Operational Taxonomic Units (OTUs) related to sequences of marine microorganisms, which is consistent with current models of fjord circulation. We conclude that meltwater can significantly modify the structure of microbial communities and support the development of a major fraction of microorganisms in surface waters of Patagonian fjords.

  4. Sub-tidal Circulation in a deep-silled fjord: Douglas Channel, British Columbia (Canada)

    NASA Astrophysics Data System (ADS)

    Wan, Di; Hannah, Charles; Foreman, Mike

    2016-04-01

    Douglas Channel, a deep fjord on the west coast of British Columbia, Canada, is the main waterway in Kitimat fjord system that opens to Queen Charlotte Sound and Hecate Strait. The fjord is separated from the open shelf by a broad sill that is about 150 m deep, and there is another sill (200 m) that separates the fjord into an outer and an inner basin. This study examines the low-frequency (from seasonal to meteorological bands) circulation in Douglas Channel from data collected from three moorings deployed during 2013-2015, and the water property observations collected during six cruises (2014 and 2015). Estuarine flow dominates the circulation above the sill-depth. The deep flows are dominated by a yearly renewal that takes place from early June to September, and this dense water renews both basins in the form of gravity currents at 0.1 - 0.2 m/s with a thickness of 100 m. At other times of the year, the deep flow structures and water properties suggest horizontal and vertical processes and support the re-circulation idea in the inner and the outer basins. The near surface current velocity fluctuations are dominated by the along-channel wind. Overall, the circulation in the meteorological band is a mix of the estuarine flow, direct wind driven flow, and the baroclinic response to changes to the surface pressure gradient caused by the wind driven currents.

  5. Vertical transport of particulate organic matter regulated by fjord topography

    NASA Astrophysics Data System (ADS)

    Erlandsson, Carina P.

    2008-03-01

    The deepwater in many areas with restricted water exchange suffers from low oxygen concentrations due to degradation of organic matter. The objective of this study was to investigate how topography may influence the vertical transport, Fc, of particulate organic matter, POM, to the deepwater. A conceptual/analytical model for Fc was developed covering the combination of the three possible sources of POM/nutrients to an enclosed area; the coastal water, local supply, and nutrient rich local deepwater. The mathematical formulation of the conceptual model includes several factors describing to which degree various physical mechanisms in the fjord are influencing Fc. The model consists of submodels for the different sources of POM/nutrients. A one-dimensional process oriented numerical model was used to test the conceptual model. Restricted water exchange with the coastal water led to decreased import of POM and thereby decreased vertical transport, Fc, of coastal POM. The contribution to Fc by local input of nutrients to the surface layer was described by a function of the residence time of the water above sill level, Tsw and the time Tp it takes for POM produced in the surface layer to settle below sill level. The recirculation of POM produced due to basin water renewals was shown to be a function of several factors: The relation between the depth of photic zone, Hp and the sill depth, Ht, the vertical velocity of the rising nutrient rich water mass versus the settling velocity of POM, etc. The results based on the conceptual submodels agreed well with the results from the process oriented numerical model. Methods to identify the trophic state of coastal waters, and also simple models to calculate the effect of a local point source, can be found in literature. However, using the model developed in this paper the effects of nutrient enrichment from different sources can be quantified in a simple and more efficient way than earlier. The model can thus be used to

  6. Subduction of thick crust: the Alaska example (Invited)

    NASA Astrophysics Data System (ADS)

    Abers, G. A.; Kim, Y.; Christensen, D. H.

    2013-12-01

    It is a paradigm of plate tectonics that oceanic lithosphere subducts readily, while lithosphere transporting much thicker continental crust does not. Analyses of plate buoyancy have included a variety of effects, such as eclogitization, crustal compositional stratification, and plate strength, but all lead to the conclusion that crust needs to be thinner than about 15-25 km in order to subduct. A test of this conclusion is underway in southern Alaska, where the Yakutat terrane is being driven by the Pacific plate into the Alaskan margin. Its crust is 15-30 km thick, varying along strike, with a seismic velocity structure resembling an oceanic plateau; thus it spans the predicted limit in thickness of subductable crust. In the eastern thicker part, the terrane appears to be colliding and driving orogenesis in the St. Elias-Chugach ranges, although voluminous volcanism of the Wrangell Volcanic Field may be a consequence of some crust subducting. Farther west, the Yakutat terrane is 15-20 km thick and clearly subducting beneath the Prince William Sound and Kenai Peninsula. It forms the slab subducting beneath the central Alaska Range 400 km inland. The thick crust has been imaged at all depths less than 130 km, through receiver functions, travel-time tomography, and offshore by active-source imaging, with similar structure in most images. Greater than 130 km depth the imaged crust vanishes in seismic images, consistent with predicted depths of eclogitization of weakly hydrated metagabbroic crust, and the lack of a velocity contrast between eclogite and peridotite. Lithosphere including the thick Yakutat crust gives a net buoyancy close to neutral, so its subduction will depend on other factors. The high buoyancy may be responsible for the remarkably shallow dip of the plate at depths less than 50 km, producing one of the widest seismogenic thrust zones on the planet, allowing it to host the great (Mw 9.3) 1964 Gulf of Alaska earthquake. The shallow dip may also aid

  7. Last glacial ice-sheet dynamics and deglaciation on Svalbard inferred from fjord records

    NASA Astrophysics Data System (ADS)

    Forwick, Matthias; Baeten, Nicole J.; Bunin, Elizabeth; Hansen, Trude; Kempf, Philipp; Velle, Julie H.; Sverre Laberg, Jan

    2015-04-01

    Various glacigenic landforms and sedimentary processes identified in the Spitsbergen fjords provide valuable insights into the dynamics of the northwestern parts of the Svalbard Barents Sea Ice Sheet during the last glacial. Glacial linear features oriented parallel to most fjord axes are identified on swath-bathymetry and high-resolution sub-bottom profiler data. They provide evidence of locally fast-flowing grounded ice draining the northwestern parts of the Svalbard Barents Sea Ice Sheet to the shelf breaks off north and west Svalbard. Eskers overlying glacial lineations reveal the existence of englacial or sub-glacial drainage systems that developed after the termination of fast ice flow. Iceberg ploughmarks suggest that parts of the deglaciation occurred by iceberg calving. Multiple transverse ridges, e.g. grounding zone wedges and moraines, indicate that multiple halts and/or readvances interrupted the deglaciations of the fjords. This includes relatively small moraines, probably deposited during halts and/or readvances in consecutive winters, thus, allowing the calculation of annual retreat rates of the ice fronts in certain fjord areas. Their regular spacing may suggest that e.g. parts of Billefjorden, Smeerenburgfjorden and Woodfjorden were deglaciated at relatively constant rates of at least 140 m/year. However, the deglaciation of van Keulenfjorden accelerated from approx. 80 m/year to about 190 m/year. Lithological analyses allow the study of sub-glacial, glacier-proximal and glacier-distal sedimentary processes and environments, as well as the identification of influences from various sediment sources. They reveal, furthermore, that the deglaciations of multiple fjords terminated quasi-synchronously around 11,200 cal. years BP, but that significant local delays of up to several thousand years occurred.

  8. Impact of ice melting on distribution of particulate sterols in glacial fjords of Chilean Patagonia

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Marcelo H.; Riquelme, Pablo; Pantoja, Silvio

    2016-04-01

    We analyzed variability in abundance and composition of sterols in waters of the fjord adjacent to glacier Jorge Montt, one of the fastest retreated glaciers in Patagonian Icefields. The study was carried out between August 2012 and November 2013 under different meltwater scenarios. Distribution of sterols in surface and bottom waters was determined by Gas Chromatography coupled to Mass Spectrometry. Sterol concentration ranged from 18 to 1726 ng/L in surface and bottom waters and was positive correlated with chlorophyll-a concentration. Under high melting conditions in austral summer, surface meltwaters showed high concentrations of sterols and were dominated by methylene-cholesterol, a representative sterol of centric diatoms. In the area near open ocean and in austral autumn, winter and spring in proglacial fjord, lower sterol concentrations in surface waters were accompanied by other microalgae sterols and an increase in relative abundance of plant sterols, evidencing a different source of organic matter. In autumn, when high meltwater flux was also evidenced, presence of stanols and an uncommon tri-unsaturated sterol suggests influence of meltwaters in composition of sterols in the downstream fjord. We conclude that ice melting can modify sterol composition by setting conditions for development of a singular phytoplankton population able to thrive in surface meltwater and by carrying glacier organic matter into Patagonian glacial fjords. In projected ice melting scenario, these changes in organic matter quantity and quality can potentially affect availability of organic substrates for heterotrophic activity and trophic status of glacial fjords. This research was funded by COPAS Sur-Austral (PFB-31)

  9. Seasonal variations of phytoplankton dynamics in Nunatsiavut fjords (Labrador, Canada) and their relationships with environmental conditions

    NASA Astrophysics Data System (ADS)

    Simo-Matchim, Armelle-Galine; Gosselin, Michel; Blais, Marjolaine; Gratton, Yves; Tremblay, Jean-Éric

    2016-04-01

    We assessed phytoplankton dynamics and its environmental control in four Labrador fjords (Nachvak, Saglek, Okak, and Anaktalak) during summer, early fall and late fall. Primary production and chlorophyll a (chl a) biomass were measured at seven optical depths, including the depth of subsurface chl a maximum (SCM). Phytoplankton abundance, size structure and taxonomy were determined at the SCM. Principal component analysis and non-metric multidimensional scaling were used to analyze relationships between production, biomass and community composition in relation to environmental variables. We observed a marked seasonal variability, with significant differences in phytoplankton structure and function between summer and fall. Surprisingly, primary production and chl a biomass were not significantly different from one fjord to another. The highest values of primary production (1730 mg C m- 2 day- 1) and chl a biomass (96 mg chl a m- 2) were measured during the summer bloom, and those high values indicate that Labrador fjords are highly productive ecosystems. The summer community showed relatively high abundance of nanophytoplankton (2-20 μm) while the fall community was characterized by low primary production and chl a biomass as well as relatively high abundance of picophytoplankton (< 2 μm). The low value of carbon potentially exported out of the euphotic zone throughout the study (≤ 31% of total primary production) suggests that phytoplankton production was mainly grazed by microzooplankton rather than being exported to greater depths. We observed a mixed assemblage of diatoms and flagellates in summer, whereas the fall community was largely dominated by flagellates. Seasonal variations in phytoplankton dynamics were mainly controlled by the strength of the vertical stratification and by the large differences in day length due to the northerly location of Labrador fjords. This study documents for the very first time phytoplankton structure and function in

  10. Alaska Library Directory, 1996.

    ERIC Educational Resources Information Center

    Jennings, Mary, Ed.

    This directory of Alaska's Libraries lists: members of the Alaska Library Association (AkLA) Executive Council and Committee Chairs; State Board of Education members; members of the Governor's Advisory Council on Libraries; school, academic and public libraries and their addresses, phone and fax numbers, and contact persons; personal,…

  11. Renewable Energy in Alaska

    SciTech Connect

    Not Available

    2013-03-01

    This report examines the opportunities, challenges, and costs associated with renewable energy implementation in Alaska and provides strategies that position Alaska's accumulating knowledge in renewable energy development for export to the rapidly growing energy/electric markets of the developing world.

  12. Alaska geothermal bibliography

    SciTech Connect

    Liss, S.A.; Motyka, R.J.; Nye, C.J.

    1987-05-01

    The Alaska geothermal bibliography lists all publications, through 1986, that discuss any facet of geothermal energy in Alaska. In addition, selected publications about geology, geophysics, hydrology, volcanology, etc., which discuss areas where geothermal resources are located are included, though the geothermal resource itself may not be mentioned. The bibliography contains 748 entries.

  13. Crustal Deformation in Southcentral Alaska: The 1964 Prince William Sound Earthquake Subduction Zone

    NASA Technical Reports Server (NTRS)

    Cohen, Steven C.; Freymueller, Jeffrey T.

    2003-01-01

    This article, for Advances in Geophysics, is a summary of crustal deformation studies in southcentral Alaska. In 1964, southcentral Alaska was struck by the largest earthquake (moment magnitude 9.2) occurring in historical times in North America and the second largest earthquake occurring in the world during the past century. Conventional and space-based geodetic measurements have revealed a complex temporal-spatial pattern of crustal movement. Numerical models suggest that ongoing convergence between the North America and Pacific Plates, viscoelastic rebound, aseismic creep along the tectonic plate interface, and variable plate coupling all play important roles in controlling both the surface and subsurface movements. The geodetic data sets include tide-gauge observations that in some cases provide records back to the decades preceding the earthquake, leveling data that span a few decades around the earthquake, VLBI data from the late 1980s, and GPS data since the mid-1990s. Geologic data provide additional estimates of vertical movements and a chronology of large seismic events. Some of the important features that are revealed by the ensemble of studies that are reviewed in this paper include: (1) Crustal uplift in the region that subsided by up 2 m at the time of the earthquake is as much as 1 m since the earthquake. In the Turnagain Arm and Kenai Peninsula regions of southcentral Alaska, uplift rates in the immediate aftermath of the earthquake reached 150 mm/yr , but this rapid uplift decayed rapidly after the first few years following the earthquake. (2) At some other locales, notably those away the middle of the coseismic rupture zone, postseismic uplift rates were initially slower but the rates decay over a longer time interval. At Kodiak Island, for example, the uplift rates have been decreasing at a rate of about 7mm/yr per decade. At yet other locations, the uplift rates have shown little time dependence so far, but are thought not to be sustainable

  14. Ground-Water Age and its Water-Management Implications, Cook Inlet Basin, Alaska

    USGS Publications Warehouse

    Glass, Roy L.

    2002-01-01

    The Cook Inlet Basin encompasses 39,325 square miles in south-central Alaska. Approximately 350,000 people, more than half of Alaska?s population, reside in the basin, mostly in the Anchorage area. However, rapid growth is occurring in the Matanuska?Susitna and Kenai Peninsula Boroughs to the north and south of Anchorage. Ground-water resources provide about one-third of the water used for domestic, commercial and industrial purposes in the Anchorage metropolitan area and are the sole sources of water for industries and residents outside Anchorage. In 1997, a study of the Cook Inlet Basin was begun as part of the U.S. Geological Survey?s National Water-Quality Assessment Program. Samples of ground water were collected from 35 existing wells in unconsolidated glacial and alluvial aquifers during 1999 to determine the regional quality of ground water beneath about 790 mi2 of developed land and to gain a better understanding of the natural and human factors that affect the water quality (Glass, 2001). Of the 35 wells sampled, 31 had water analyzed for atmospherically derived substances to determine the ground water?s travel time from its point of recharge to its point of use or discharge?also known as ground-water age. Ground water moves slowly from its point of recharge to its point of use or discharge. This water starts as rain and melting snow that soak into the ground as recharge. In the Matanuska?Susitna, Anchorage, and Kenai Peninsula areas, ground water generally moves from near the mountain fronts toward Cook Inlet or the major rivers. Much of the water pumped by domestic and public-supply wells may have traveled less than 10 miles, and the trip may have taken as short a time as a few days or as long as several decades. This ground water is vulnerable to contamination from the land surface, and many contaminants in the water would follow the same paths and have similar travel times from recharge areas to points of use as the chemical substances analyzed in

  15. Tectonics of the March 27, 1964, Alaska earthquake: Chapter I in The Alaska earthquake, March 27, 1964: regional effects

    USGS Publications Warehouse

    Plafker, George

    1969-01-01

    The March 27, 1964, earthquake was accomp anied by crustal deformation-including warping, horizontal distortion, and faulting-over probably more than 110,000 square miles of land and sea bottom in south-central Alaska. Regional uplift and subsidence occurred mainly in two nearly parallel elongate zones, together about 600 miles long and as much as 250 miles wide, that lie along the continental margin. From the earthquake epicenter in northern Prince William Sound, the deformation extends eastward 190 miles almost to long 142° and southwestward slightly more than 400 miles to about long 155°. It extends across the two zones from the chain of active volcanoes in the Aleutian Range and Wrangell Mountains probably to the Aleutian Trench axis. Uplift that averages 6 feet over broad areas occurred mainly along the coast of the Gulf of Alaska, on the adjacent Continental Shelf, and probably on the continental slope. This uplift attained a measured maximum on land of 38 feet in a northwest-trending narrow belt less than 10 miles wide that is exposed on Montague Island in southwestern Prince William Sound. Two earthquake faults exposed on Montague Island are subsidiary northwest-dipping reverse faults along which the northwest blocks were relatively displaced a maximum of 26 feet, and both blocks were upthrown relative to sea level. From Montague Island, the faults and related belt of maximum uplift may extend southwestward on the Continental Shelf to the vicinity of the Kodiak group of islands. To the north and northwest of the zone of uplift, subsidence forms a broad asymmetrical downwarp centered over the Kodiak-Kenai-Chugach Mountains that averages 2½ feet and attains a measured maximum of 7½ feet along the southwest coast of the Kenai Peninsula. Maximum indicated uplift in the Alaska and Aleutian Ranges to the north of the zone of subsidence was l½ feet. Retriangulation over roughly 25,000 square miles of the deformed region in and around Prince William Sound

  16. Alaska marine ice atlas

    SciTech Connect

    LaBelle, J.C.; Wise, J.L.; Voelker, R.P.; Schulze, R.H.; Wohl, G.M.

    1982-01-01

    A comprehensive Atlas of Alaska marine ice is presented. It includes information on pack and landfast sea ice and calving tidewater glacier ice. It also gives information on ice and related environmental conditions collected over several years time and indicates the normal and extreme conditions that might be expected in Alaska coastal waters. Much of the information on ice conditions in Alaska coastal waters has emanated from research activities in outer continental shelf regions under assessment for oil and gas exploration and development potential. (DMC)

  17. Libraries in Alaska: MedlinePlus

    MedlinePlus

    ... this page: https://medlineplus.gov/libraries/alaska.html Libraries in Alaska To use the sharing features on ... JavaScript. Anchorage University of Alaska Anchorage Alaska Medical Library 3211 Providence Drive Anchorage, AK 99508-8176 907- ...

  18. 75 FR 53331 - Alaska Native Claims Selection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-31

    ... Interest to Hadohdleekaga, Incorporated, for the Native village of Hughes, Alaska, pursuant to the Alaska... Hughes, Alaska, and are located in: Kateel River Meridian, Alaska T. 9 N., R. 23 E., Sec. 5....

  19. Peatland Carbon Dynamics in Alaska During Past Warm Climates

    NASA Astrophysics Data System (ADS)

    Yu, Z.; Cleary, K.; Massa, C.; Hunt, S. J.; Klein, E. S.; Loisel, J.

    2013-12-01

    Peatlands represent a large belowground carbon (C) pool in the biosphere. However, how peatland C sequestration capacity varies with changes in climate and climate-induced disturbance is still poorly understood and debated. Here we summarize results from Alaskan peatlands to document how peat C accumulation has responded to past warm climate intervals. We find that the greatest C accumulation rates at sites from the Kenai Peninsula to the North Slope occurred during the Holocene thermal maximum (HTM) in the early Holocene. This time period also corresponds with explosive formation and expansion of new peatlands on the landscape across Alaska. In addition, we note that many peatlands that existed during the earlier Holocene on the North Slope have disappeared and are presently covered by mineral soils under tundra or sandy deposits. During the Medieval Climate Anomaly (MCA) around 1000-500 years ago, several peatlands in Alaska show high rates of C accumulation when compared to the period before the MCA during the Neoglacial or the following Little Ice Age period. Altogether, our results indicate that the Alaskan landscape was very different during the last 10,000 years and that peatlands can rapidly accumulate C under warm climatic conditions. We speculate that warmth-stimulated increase in plant production surpasses increase in peat decomposition during the early Holocene, and potentially also during the MCA. Other factors that might have contributed to rapid peat accumulation during the early Holocene include increased summer sunlight, lowered sea levels, and decreased sea-ice cover/duration. Summer insolation was ca. 8% higher than today during the early Holocene due to orbital variations, which likely promoted plant productivity by increasing growing seasons sunlight. Furthermore, lower sea levels and exposed shallow continental shelves in the Beaufort Sea (Arctic Ocean) would have made the present-day Arctic Coastal Plain more continental, with warmer summers

  20. Alaska telemedicine: growth through collaboration.

    PubMed

    Patricoski, Chris

    2004-12-01

    The last thirty years have brought the introduction and expansion of telecommunications to rural and remote Alaska. The intellectual and financial investment of earlier projects, the more recent AFHCAN Project and the Universal Service Administrative Company Rural Health Care Division (RHCD) has sparked a new era in telemedicine and telecommunication across Alaska. This spark has been flamed by the dedication and collaboration of leaders at he highest levels of organizations such as: AFHCAN member organizations, AFHCAN Office, Alaska Clinical Engineering Services, Alaska Federal Health Care Partnership, Alaska Federal Health Care Partnership Office, Alaska Native health Board, Alaska Native Tribal health Consortium, Alaska Telehealth Advisory Council, AT&T Alascom, GCI Inc., Health care providers throughout the state of Alaska, Indian Health Service, U.S. Department of Health and Human Services, Office of U.S. Senator Ted Steens, State of Alaska, U.S. Department of Homeland Security--United States Coast Guard, United States Department of Agriculture, United States Department of Defense--Air Force and Army, United States Department of Veterans Affairs, University of Alaska, and University of Alaska Anchorage. Alaska now has one of the largest telemedicine programs in the world. As Alaska moves system now in place become self-sustaining, and 2) collaborating with all stakeholders in promoting the growth of an integrated, state-wide telemedicine network.

  1. Melting glacier impacts the community structure of Bacteria, Fungi and Archaea in Chilean Patagonia fjord system

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Marcelo, ,, Dr.; Galand, Pierre; Moffat, Carlos; Pantoja, Silvio

    2014-05-01

    Seasonal and spatial variability in microbial community composition was studied by analyzing sequences of Bacteria, Archaea and Fungi in the fjord adjacent to the glacier Jorge Montt (48º20'S; 73º30' W), which has evidenced one of the most significant retreats during the past century in Patagonian Icefields. A detailed description of prokaryotic (Bacteria and Archaea) and fungal communities was carried out by pyrosequencing of 16S rRNA gene and the ITS region, respectively. Our results showed high diversity of operational taxonomic units (OTUs) in bacteria followed by the fungal community. In contrast, Archaea was characterized by low OTU abundance in most of the sampling sites and depths. Similarity in OTU composition evidenced a microbial community structure associated with hydrographic features of the fjord basin, where strong stratification maintained by the continuous input of meltwaters produces differences in the microbial composition between surface and bottom waters. Our results also showed seasonal changes in microbial components, evidencing the presence of OTUs related to cold and glacier environments in surface waters during autumn, when a wider layer of meltwater was observed. We identified at least three different microbial communities inhabiting the downstream fjord ecosystem: i) a surface waters community in autumn, with a predominance of OTUs matching with Cyanobacteria, ii) a bottom water community in autumn, where fungal OTUs predominated, and iii) a microbial community during winter with a significant presence of OTUs of Archaea. The composition of these microbial communities agrees with patterns of bacterial communities in glacial environments, marine sediments and waters and with fungal composition in coastal, marine and continental airborne. Our results indicate that hydrodynamic and water column characteristics play a main role in structuring microbial community and suggest that the progressive input of meltwater can strongly impacts the

  2. Palaeoceanographic changes in Hornsund Fjord (Spitsbergen, Svalbard) over the last millennium: new insights from ancient DNA

    NASA Astrophysics Data System (ADS)

    Pawłowska, Joanna; Zajączkowski, Marek; Łącka, Magdalena; Lejzerowicz, Franck; Esling, Philippe; Pawlowski, Jan

    2016-07-01

    This paper presents a reconstruction of climate-driven environmental changes over the last millennium in Hornsund Fjord (Svalbard), based on sedimentological and micropalaeontological records. Our palaeo-investigation was supported by an analysis of foraminiferal ancient DNA (aDNA), focusing on the non-fossilized monothalamous species. The main climatic fluctuations during the last millennium were the Medieval Warm Period (MWP, AD 1000-1600), the Little Ice Age (LIA, AD 1600-1900) and the modern warming (MW, AD 1900 to present). Our study indicates that the environmental conditions in Hornsund during the MWP and the early LIA (before ˜ AD 1800) were relatively stable. The beginning of the LIA (˜ AD 1600) was poorly evidenced by the micropalaeontological record but was well marked in the aDNA data by an increased proportion of monothalamous foraminifera, especially Bathysiphon sp. The early LIA (˜ 1600 to ˜ AD 1800) was marked by an increase in the abundance of sequences of Hippocrepinella hirudinea and Cedhagenia saltatus. In the late LIA (after ˜ AD 1800), the conditions in the fjord became glacier-proximal and were characterized by increased meltwater outflows, high sedimentation and a high calving rate. This coincided with an increase in the percentages of sequences of Micrometula sp. and Vellaria pellucidus. During the MW, the major glacier fronts retreated rapidly to the inner bays, which limited the iceberg discharge to the fjord's centre and caused a shift in the foraminiferal community that was reflected in both the fossil and aDNA records. The palaeoceanographic changes in the Hornsund fjord over the last millennium were driven mainly by the inflow of shelf-originated water masses and glacial activity. However, the environmental changes were poorly evidenced in the micropalaeontological record, but they were well documented in our aDNA data. We considerably increased the number of potential proxy species by including monothalamous foraminifera in the

  3. Alaska: A frontier divided

    SciTech Connect

    O'Dell, R. )

    1986-09-01

    The superlatives surrounding Alaska are legion. Within the borders of the 49th US state are some of the world's greatest concentrations of waterfowl, bald eagles, fur seals, walrus, sea lions, otters, and the famous Kodiak brown bear. Alaska features the highest peak of North America, the 20,320-foot Mount McKinley, and the longest archipelago of small islands, the Aleutians. The state holds the greatest percentage of protected wilderness per capita in the world. The expanse of some Alaskan glaciers dwarfs entire countries. Like the periodic advance and retreat of its glaciers, Alaska appears with some regularity on the national US agenda. It last achieved prominence when President Jimmy Carter signed the Alaska National Interest Lands Conservation Act in 1980. Since then the conflict between environmental protection and economic development has been played out throughout the state, and Congress is expected to turn to Alaskan issues again in its next sessions.

  4. Synthesis of polycyclic aromatic hydrocarbon modified 2 prime -deoxyadenosine analogs and the first fjord region tetrahydroepoxide

    SciTech Connect

    Lakshman, M.

    1989-01-01

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental contaminants, which can be metabolized to carcinogens. Research in this field has shown that the diol epoxides are the metabolites of these PAH that are responsible for carcinogenic activity. These metabolites generally possess a sterically hindered bay or fjord region. In an effort at understanding the structural requirements of these fjord region PAH, we have synthesized the fjord region tetrahydroepoxide of benzo(g)chrysene. The compound described in this dissertation is expected to be more biologically active as compared to the diol epoxide in the same tetrahydro ring. PAH diol epoxides are known to intercalate and bind covalently to DNA. Evidence suggests that binding of these diol epoxides to DNA causes mutations. However, the exact mechanism of carcinogenesis at the molecular level is as yet unknown. This led us to the synthesis of PAH substituted nucleosides. These nucleosides could be incorporated into oligonucleotides and used for site directed mutagenesis. The effect of PAH diol epoxide binding on DNA conformation could also be probed. This dissertation, therefore, describes the initial efforts in the synthesis of these PAH substituted mononucleosides. The synthetic scheme involved synthesis of activated purine nucleosides and the appropriately substituted PAH derivative. Finally two PAH substituted 2{prime}-deoxyadenosine analogs (naphthalene and benzo(a)pyrene), were synthesized.

  5. Geochemical characterisation of northern Norwegian fjords sediments: A source to sink study

    NASA Astrophysics Data System (ADS)

    Faust, Johan; Knies, Jochen; Scheiber, Thomas

    2016-04-01

    To provide a better understanding of the weathering, transportation and sedimentation processes in a complex fjord system forty-four surface sediment samples plus three sediment cores were recovered from the Vestfjord, Ofotfjord and Tysfjord in northern Norway. We analysed the elemental composition, Corg, bulk mineral composition, CaCO3, grain size and C, Nd, Sr and Hf isotopes. We found that the Vestfjord, Ofotfjord and Tysfjord can be characterised and separated by distinct geochemical signatures of the surface sediment samples e.g. in the distribution of REE and the relation between grain size and Ni, Fe and K. These variations are related to differences in the hinterland bedrock composition. The bedrock in the drainage area of these fjords consist mainly of para- and orthogneiss. Onshore soil and bedrock geochemistry data show that the orthogneiss can be distinguished from the paragneiss by the different content of Th, K, Mg, Ni and Fe. Moreover, a limestone formation rich in dolomite can be traced in the fjord system using the calcite/dolomite ratio. The investigation of the sediment cores shows that these parameters can be used as a geochemical fingerprint to trace the different rock types throughout the entire Holocene. This finding will also help to gain more knowledge about the timing of the past deglaciation and sea level variations in northern Norway.

  6. Calving Signature in Ocean Waves: Helheim Glacier and Sermilik Fjord Dynamics

    NASA Astrophysics Data System (ADS)

    Vankova, I.; Holland, D.

    2015-12-01

    In this work, we investigate the characteristics of calving on Helheim glacier from data recorded on an array of five high frequency pressure meters placed along Sermilik fjord. Calving generated tsunami waves were recorded and used to construct a calving event catalog and to characterize the post-calving ocean state. Calving on Helheim is highly seasonal: it onsets after months of inactivity in early spring, immediately following the rise of daily average temperatures above freezing point, which indicates the potentially dominant role of meltwater in the calving mechanism. Tidal phase and amplitude, ocean temperature variations or surges did not seem to be significant calving factors. In the ocean spectra, we observe discrete peaks between 0.4 to 6 mHz associated with calving events. These peak frequencies are consistent among all the events and they travel as propagating modes up and down the fjord for several hours while being slowly radiated away to the open ocean, an observation which we support with a model. Large part of the spectrum is trapped in evanescent modes or is quickly dissipated. These observations are relevant for our understanding of the time scale and rate of mixing in glacier fjords, and eventually for improving boundary conditions for ocean models.

  7. Alaska looks HOT!

    SciTech Connect

    Belcher, J.

    1997-07-01

    Production in Alaska has been sluggish in recent years, with activity in the Prudhoe Bay region in the North Slope on a steady decline. Alaska North Slope (ANS) production topped out in 1988 at 2.037 MMbo/d, with 1.6 MMbo/d from Prudhoe Bay. This year operators expect to produce 788 Mbo/d from Prudhoe Bay, falling to 739 Mbo/d next year. ANS production as a whole should reach 1.3 MMbo/d this year, sliding to 1.29 MMbo/d in 1998. These declining numbers had industry officials and politicians talking about the early death of the Trans-Alaskan Pipeline System-the vital link between ANS crude and markets. But enhanced drilling technology coupled with a vastly improved relationship between the state government and industry have made development in Alaska more economical and attractive. Alaska`s Democratic Gov. Tommy Knowles is fond of telling industry {open_quotes}we`re open for business.{close_quotes} New discoveries on the North Slope and in the Cook Inlet are bringing a renewed sense of optimism to the Alaska exploration and production industry. Attempts by Congress to lift a moratorium on exploration and production activity in the Arctic National Wildlife Refuge (ANWR) have been thwarted thus far, but momentum appears to be with proponents of ANWR drilling.

  8. Last glacial ice sheet dynamics and deglaciation on Svalbard inferred from fjord records (Invited)

    NASA Astrophysics Data System (ADS)

    Forwick, M.; Vorren, T. O.; Baeten, N. J.; Hansen, T.; Kempf, P.; Velle, J. H.; Laberg, J.

    2013-12-01

    Swath bathymetry, high-resolution sub-bottom profiles and sediment cores from fjords on north and west Svalbard document a variety of glacigenic landforms and sedimentary processes, providing valuable insights into the dynamics of the northwestern parts of the Svalbard Barents Sea Ice Sheet during the last glacial. Glacial linear features oriented parallel to most fjord axes are identified on swath-bathymetry and high-resolution sub-bottom profiler data. They provide evidence of locally fast-flowing grounded ice draining the northwestern parts of the Svalbard Barents Sea Ice Sheet to the shelf breaks off north and west Svalbard. Eskers overlying glacial lineations reveal the existence of englacial or sub-glacial drainage systems that developed after the termination of fast ice flow. Iceberg ploughmarks suggest that parts of the deglaciation occurred by iceberg calving. Multiple transverse ridges, e.g. grounding zone wedges and moraines, indicate that multiple halts and/or readvances interrupted the deglaciations of the fjords. This includes relatively small moraines, probably deposited during halts and/or readvances in consecutive winters, thus, allowing the calculation of annual retreat rates of the ice fronts in certain fjord areas. Their regular spacing may suggest that e.g. parts of Billefjorden, Smeerenburgfjorden and Woodfjorden were deglaciated at relatively constant rates of at least 140 m/year. However, the deglaciation of van Keulenfjorden accelerated from approx. 80 m/year to about 190 m/year. Lithological analyses allow the study of sub-glacial, glacier-proximal and glacier-distal sedimentary processes and environments, as well as the identification of influences from various sediment sources. They reveal, furthermore, that the deglaciations of multiple fjords terminated quasi-synchronously around 11,200 cal. years BP, but that significant local delays of up to several thousand years occurred. We present examples of the above mentioned landforms

  9. Mapping Submarine Groundwater Discharge into Ringkøbing Fjord, Denmark

    NASA Astrophysics Data System (ADS)

    Kinnear, J. A.; Binley, A.; Engesgaard, P. K.; Duque, C.; Haider, K.

    2011-12-01

    Accounting for submarine groundwater discharge (SGWD), as a fraction of the total water budget of a catchment, is a challenging task due to the diffuse nature of the process in the coastal zone. Geophysical techniques, however, provide an effective means of gathering spatial data that relate to the potential for upwelling at the groundwater-surface water interface. This study attempts to map SGWD, using terrain conductivity geophysical techniques, in the shallow, brackish water Ringkøbing Fjord lagoon in western Jutland, Denmark. This will help assess whether the groundwater input is a significant part of the water budget for the Skjern River catchment (the largest catchment in Denmark), which flows into the lagoon. Previous surveys using conventional techniques (e.g. seepage meters) have revealed the potential for localised upwelling, however, these methods offered limited ability to map extensive areas. With the geophysical method however, high resolution mapping of the terrain conductivity was achieved, using a Geonics EM31 device in a water-borne configuration, coupled with measurements of water depth and fluid electrical conductivity. The EM31 measurements have been interpreted using a two layer model: the upper layer represents the surface water body with known depth and conductivity; the lower layer represents the fjord bed sediments. It is assumed that areas of the fjord associated with fresh groundwater upwelling from the catchment are evidenced by bed sediments with relatively low electrical conductivity. The results (figure 1) show a rapid increase in conductivity within 25m of the shoreline from values around 20mS/m at the shore, to peaks of around 225mS/m. Beyond 25m offshore the conductivity decreases slightly and then increases steadily up to ~450m offshore in a region that is relatively homogenous compared to the sharp gradient close to the shore. The results suggest that most of the upwelling of fresh groundwater, from the Skjern catchment into

  10. Tidal analysis of surface currents in the Porsanger fjord in northern Norway

    NASA Astrophysics Data System (ADS)

    Stramska, Malgorzata; Jankowski, Andrzej; Cieszyńska, Agata

    2016-04-01

    In this presentation we describe surface currents in the Porsanger fjord (Porsangerfjorden) located in the European Arctic in the vicinity of the Barents Sea. Our analysis is based on data collected in the summer of 2014 using High Frequency radar system. Our interest in this fjord comes from the fact that this is a region of high climatic sensitivity. One of our long-term goals is to develop an improved understanding of the undergoing changes and interactions between this fjord and the large-scale atmospheric and oceanic conditions. In order to derive a better understanding of the ongoing changes one must first improve the knowledge about the physical processes that create the environment of the fjord. The present study is the first step in this direction. Our main objective in this presentation is to evaluate the importance of tidal forcing. Tides in the Porsanger fjord are substantial, with tidal range on the order of about 3 meters. Tidal analysis attributes to tides about 99% of variance in sea level time series recorded in Honningsvåg. The most important tidal component based on sea level data is the M2 component (amplitude of ~90 cm). The S2 and N2 components (amplitude of ~ 20 cm) also play a significant role in the semidiurnal sea level oscillations. The most important diurnal component is K1 with amplitude of about 8 cm. Tidal analysis lead us to the conclusion that the most important tidal component in observed surface currents is also the M2 component. The second most important component is the S2 component. Our results indicate that in contrast to sea level, only about 10 - 20% of variance in surface currents can be attributed to tidal currents. This means that about 80-90% of variance can be credited to wind-induced and geostrophic currents. This work was funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support for MS comes from the Institute of Oceanology (IO PAN).

  11. Linking the spatial variability of glacier mass loss to fjord geometry

    NASA Astrophysics Data System (ADS)

    Porter, D. F.; Tinto, K. J.; Boghosian, A.; Cochran, J. R.; Csatho, B. M.; Bell, R. E.

    2015-12-01

    There is compelling evidence of increasing mass loss of the ice sheets using a diverse set of observations, including increased thinning rates measured from both airborne and satellite altimeters, elevated mass fluxes resulting from the acceleration of outlet glaciers, and mass changes measured directly from satellite gravimetry. A dominant characteristic of observed change in Greenland outlet glaciers is that it is locally random. Numerous studies have revealed a high degree of spatial and temporal variability of outlet glacier mass change. Modeling studies suggest that increased ocean temperatures may be responsible for the observed glacial retreat in Greenland through increased basal melting, leading to increased calving rates, terminus retreat, glacier speedup, and eventually thinning of inland ice. Knowledge of fjord geometry is crucial for ice-ocean interaction because the availability of ocean heat to the ice will be restricted by narrow sills and shallow grounding lines. We investigate whether the variability in observed changes among Greenland glaciers can be partially explained by variation in fjord geometry. Using statistical techniques commonly employed to detect patterns in complex spatial data, we objectively show that mass change in Greenland tidewater glaciers between 2003 and 2009 is indeed mostly spatially incoherent. Except for a few clusters of similar change in the NW and Scoresby Sund regions, there is significant glacier-scale variability in mass loss rates. To understand the drivers of this local variability, we compare fjord bathymetries from all regions of Greenland, modeled using airborne gravimetry measurements from NASA Operation IceBridge flights, to estimates of glaciological change. Specifically, we investigate the correlation between water depths at the grounding line and the dynamic mass loss of tidewater glaciers. In theory, a deep grounding line will allow greater interaction with the warm Atlantic Water observed in most fjords

  12. The Potential for Biomass District Energy Production in Port Graham, Alaska

    SciTech Connect

    Charles Sink, Chugachmiut; Keeryanne Leroux, EERC

    2008-05-08

    This project was a collaboration between The Energy & Environmental Research Center (EERC) and Chugachmiut – A Tribal organization Serving the Chugach Native People of Alaska and funded by the U.S. Department of Energy (DOE) Tribal Energy Program. It was conducted to determine the economic and technical feasibility for implementing a biomass energy system to service the Chugachmiut community of Port Graham, Alaska. The Port Graham tribe has been investigating opportunities to reduce energy costs and reliance on energy imports and support subsistence. The dramatic rise in the prices of petroleum fuels have been a hardship to the village of Port Graham, located on the Kenai Peninsula of Alaska. The Port Graham Village Council views the forest timber surrounding the village and the established salmon industry as potential resources for providing biomass energy power to the facilities in their community. Benefits of implementing a biomass fuel include reduced energy costs, energy independence, economic development, and environmental improvement. Fish oil–diesel blended fuel and indoor wood boilers are the most economical and technically viable options for biomass energy in the village of Port Graham. Sufficient regional biomass resources allow up to 50% in annual heating savings to the user, displacing up to 70% current diesel imports, with a simple payback of less than 3 years for an estimated capital investment under $300,000. Distributive energy options are also economically viable and would displace all imported diesel, albeit offering less savings potential and requiring greater capital. These include a large-scale wood combustion system to provide heat to the entire village, a wood gasification system for cogeneration of heat and power, and moderate outdoor wood furnaces providing heat to 3–4 homes or community buildings per furnace. Coordination of biomass procurement and delivery, ensuring resource reliability and technology acceptance, and arbitrating

  13. Alaska Resource Data File: Chignik quadrangle, Alaska

    USGS Publications Warehouse

    Pilcher, Steven H.

    2000-01-01

    Descriptions of the mineral occurrences can be found in the report. See U.S. Geological Survey (1996) for a description of the information content of each field in the records. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska. There is a website from which you can obtain the data for this report in text and Filemaker Pro formats

  14. Fjord - Glacier Ice Interactions: Nuup Kangerlua (Godthåbsfjord) Southwest Greenland

    NASA Astrophysics Data System (ADS)

    Motyka, R. J.; Truffer, M.; Dryer, W. P.; Fahnestock, M. A.; Cassotto, R. K.; Mortensen, J.; Rysgaard, S.

    2012-12-01

    The study of interactions between glaciers, fjords, and the ocean in coastal Greenland is still in its infancy. Circulation of warm ocean waters into fjords has been hypothesized to play an important role in destabilizing and modulating glacier discharge from outlet glaciers in Greenland, but details on the dynamics of this interaction remain sparse. To help fill this gap, we conducted a series of hydrographic measurements over a six-day period in late August 2011 in the proglacial fjord Kangersuneq at the head of Nuup Kangerlua (Godthåbsfjord) near Nuuk in southwest Greenland. Because of iceberg conditions, we were unable to approach any closer than 12 km to the tidewater glacier Kangiata Nunaata Sermia (KNS) at the head of the fjord. We conducted the majority of our measurements over the KNS Little Ice Age (LIA) moraine, a sill which forms a barrier between the inner and outer fjord. The LIA sill lies about 22 km from KNS, spans the 4-km-wide fjord and has a maximum water depth of 170 m. Water depths fall to over 300 m on either side of this sill and all water entering or leaving the inner basin must flow over it. For comparison, we also conducted transects at a second location inside the inner basin, 12 km from the KNS terminus and in much deeper water (> 300 m). Our transects included shipboard CTD (conductivity, temperature, density) and current measurements, the latter using rail-mounted 150 kHz and 600 kHz RDI ADCPs (Acoustic Doppler Current Profilers). Iceberg conditions in the fjord prevented measurements while underway. The CTD measurements showed a highly stratified water column capped by a 5 m freshwater layer. The warmest (3 deg. C) and most saline water (32) lies directly over the sill, near the bottom of the water column. The freshwater fraction at 20 m water depth is 7.6% with 6.0% from subglacial freshwater discharge and 1.6% derived from submarine melting of ice. We timed our survey to bracket the neap tide to reduce complexities related to tidal

  15. Fjord-valley fill stratigraphy from onshore high-resolution shear-wave seismics, Trondheim harbour area, central Norway

    NASA Astrophysics Data System (ADS)

    Hansen, L.; Polom, U.; L'Heureux, J.; Sauvin, G.; Lecomte, I.; Krawczyk, C. M.; Longva, O.

    2009-12-01

    To obtain information on the stratigraphic variability within the underlying fjord-valley fill, a shallow, shear-wave reflection seismic survey was successfully carried out on land in the Trondheim harbor area, central Norway. Since the last deglaciation, the region has been subjected to a fall of relative sea level of totally 175 m due to glacioisostatic rebound. The relative sea-level fall was accompanied by river erosion of emerging (glacio) marine deposits, several, large landslides, and delta progradation into the fjord. The infilled harbour area is located on the submerged part of a delta plain, and land reclamation is still going on. Historic and older submarine landslides are known to have taken place along the shoreline and an improved understanding of the ground conditions is therefore valuable for engineering purposes. In addition, the unique, S-wave seismic record gives insight into the overall architecture and long-term development of a fjord-valley filling influenced by relative sea level fall accompanied by occasional major mass-wasting events. Shear-wave reflection seismics was applied using a land streamer of 120 channels combined with a newly developed shear-wave vibrator from LIAG. Overall, 4.2 profile-km were acquired in a 2.5-D grid along paved roads and parking lots during night to minimize environmental noise. The investigations achieved a highly resolved image of the fjord-valley fill and clear bedrock detection. Vertical resolution is within a few meters over the entire profile whereas horizontal resolution decreases with depth. The entire fjord-valley fill is up to 160 m thick and five main stratigraphic units have been identified including bedrock. The fjord-valley fill is interpreted as consisting of glaciomarine deposits overlain by marine fjord sediments grading upwards into deltaic deposits. The change from continuous to more discontinuous or irregular reflection patterns reflects a progressive influence of delta-derived processes and

  16. Glacier Change and Biologic Succession: a new Alaska Summer Research Academy (ASRA) Science Camp Module for Grades 8-12 in Glacier Bay National Park, Alaska

    NASA Astrophysics Data System (ADS)

    Connor, C. L.; Drake, J.; Good, C.; Fatland, R.; Hakala, M.; Woodford, R.; Donohoe, R.; Brenner, R.; Moriarty, T.

    2008-12-01

    During the summer of 2008, university faculty and instructors from southeast Alaska joined the University Alaska Fairbanks(UAF)Alaska Summer Research Academy(ASRA)to initiate a 12-day module on glacier change and biologic succession in Glacier Bay National Park. Nine students from Alaska, Colorado, Massachusetts, and Texas, made field observations and collected data while learning about tidewater glacier dynamics, plant succession, post-glacial uplift, and habitat use of terrestrial and marine vertebrates and invertebrates in this dynamic landscape that was covered by 6,000 km2 of ice just 250 years ago. ASRA students located their study sites using GPS and created maps in GIS and GOOGLE Earth. They deployed salinometers and temperature sensors to collect vertical profiles of seawater characteristics up-bay near active tidewater glacier termini and down-bay in completely deglaciated coves. ASRA student data was then compared with data collected during the same time period by Juneau undergraduates working on the SEAMONSTER project in Mendenhall Lake. ASRA students traversed actively forming, up-bay recessional moraines devoid of vegetation, and the fully reforested Little Ice Age terminal moraine near Park Headquarters in the lower bay region. Students surveyed marine organisms living between supratidal and subtidal zones near glaciers and far from glaciers, and compared up-bay and down-bay communities. Students made observations and logged sightings of bird populations and terrestrial mammals in a linear traverse from the bay's northwestern most fjord near Mt. Fairweather for 120 km to the bay's entrance, south of Park Headquarters at Bartlett Cove. One student constructed an ROV and was able to deploy a video camera and capture changing silt concentrations in the water column as well as marine life on the fjord bottom. Students also observed exhumed Neoglacial spruce forests and visited outcrops of Silurian reef faunas, now fossilized in Alexander terrane

  17. A Deglacial and Holocene Record of Climate Variability in South-Central Alaska from Stable Oxygen Isotopes and Plant Macrofossils in Peat

    NASA Technical Reports Server (NTRS)

    Jones, Miriam C.; Wooller, Matthew; Peteet, Dorothy M.

    2014-01-01

    We used stable oxygen isotopes derived from bulk peat (delta-O-18(sub TOM) in conjunction with plant macrofossils and previously published carbon accumulation records, in a approximately14,500 cal yr BP peat core (HT Fen) from the Kenai lowlands in south-central Alaska to reconstruct the climate history of the area. We find that patterns are broadly consistent with those from lacustrine records across the region, and agree with the interpretation that major shifts in delta-O-18(sub TOM) values indicate changes in strength and position of the Aleutian Low (AL), a semi-permanent low-pressure cell that delivers winter moisture to the region. We find decreased strength or a more westerly position of the AL (relatively higher delta-O-18(sub TOM) values) during the Bolling-Allerod, Holocene Thermal Maximum (HTM), and late Holocene, which also correspond to warmer climate regimes. These intervals coincide with greater peat preservation and enhanced carbon (C) accumulation rates at the HT Fen and with peatland expansion across Alaska. The HTM in particular may have experienced greater summer precipitation as a result of an enhanced Pacific subtropical high, a pattern consistent with modern delta-O-18 values for summer precipitation. The combined warm summer temperatures and greater summer precipitation helped promote the observed rapid peat accumulation. A strengthened AL (relatively lower delta-O-18(sub TOM) values) is most evident during the Younger Dryas, Neoglaciation, and the Little Ice Age, consistent with lower peat preservation and C accumulation at the HT Fen, suggesting less precipitation reaches the leeward side of the Kenai Mountains during periods of enhanced AL strength. The peatlands on the Kenai Peninsula thrive when the AL is weak and the contribution of summer precipitation is higher, highlighting the importance of precipitation seasonality in promoting peat accumulation. This study demonstrates that delta-O-18(sub TOM) values in peat can be applied

  18. Multibeam bathymetry and selected perspective views of main part of Glacier Bay, Alaska

    USGS Publications Warehouse

    Carlson, Paul R.; Hooge, Philip; Cochrane, Guy; Stevenson, Andrew; Dartnell, Pete; Lee, Kristen

    2002-01-01

    Glacier Bay is a diverse fjord ecosystem with multiple tidewater glaciers and complex biological, geological, and oceanographic patterns that vary greatly along its length. The bay was completely glaciated prior to the 1700's, and subsequently experienced the fastest glacial retreat recorded in historical times. As a result, some of the highest rates of glacial sedimentation and uplift are observed here. Glacier Bay is the deepest silled fjord in Alaska, with depths of over 450 meters. The variety of physical processes and depths creates many diverse habitats within a relatively small area. Mapping benthic (seafloor) habitats is thus crucial to understanding and managing Glacier Bay's complex marine ecosystem and the marine species therein. High-resolution multibeam mapping of the bay, funded jointly by USGS and the National Park System, provides an unprecedented new baseline for resource and habitat assessment. Full integration of the new data set will require additional ground-truthing data (sampling) and analysis. The USGS goal is to develop integrated geological and oceanographic habitat models for the marine benthos in Glacier Bay, as a step toward determining the habitat relationships of critical species and resources within the Park.

  19. Flood frequency in Alaska

    USGS Publications Warehouse

    Childers, J.M.

    1970-01-01

    Records of peak discharge at 183 sites were used to study flood frequency in Alaska. The vast size of Alaska, its great ranges of physiography, and the lack of data for much of the State precluded a comprehensive analysis of all flood determinants. Peak stream discharges, where gaging-station records were available, were analyzed for 2-year, 5-year, 10-year, 25-year, and 50-year average-recurrence intervals. A regional analysis of the flood characteristics by multiple-regression methods gave a set of equations that can be used to estimate floods of selected recurrence intervals up to 50 years for any site on any stream in Alaska. The equations relate floods to drainage-basin characteristics. The study indicates that in Alaska the 50-year flood can be estimated from 10-year gaging- station records with a standard error of 22 percent whereas the 50-year flood can be estimated from the regression equation with a standard error of 53 percent. Also, maximum known floods at more than 500 gaging stations and miscellaneous sites in Alaska were related to drainage-area size. An envelope curve of 500 cubic feet per second per square mile covered all but 2 floods in the State.

  20. Little Ice Age Glaciation in Alaska: A record of recent global climatic change

    SciTech Connect

    Calkin, P.E.; Wiles, G.C.

    1992-03-01

    General global cooling and temperature fluctuation accompanied by expansion of mountain glaciers characterized the Little Ice Age of about A.D. 1200 through A.D. 1900. The effects of such temperature changes appear first and are strongest at high latitudes. Therefore the Little Ice Age record of glacial fluctuation in Alaska may provide a good proxy for these events and a test for models of future climatic change. Holocene expansions began here as early as 7000 B.P. and locally show a periodicity of 350 years after about 4500 years B.P. The Little Ice Age followed a late Holocene interval of minor ice advance and a subsequent period of ice margin recession lasting one to seven centuries. The timing of expansions since about A.D. 1200 have often varied between glaciers, but these are the most pervasive glacial events of the Holocene in Alaska and frequently represent ice marginal maxima for this interval. At least two major expansions are, apparent in forefields of both land-terminating and fjord-calving glaciers, but the former display the most reliable and detailed climatic record. Major maxima occurred by the 16th century and into the mid-18th century. Culmination of advances occurred throughout Alaska during the 19th century followed within a few decades by general glacial retreat. Concurrently, equilibrium line altitudes have been raised 100-400 m, representing a rise of 2-3 deg C in mean summer temperature.

  1. Miocene fluvial-tidal sedimentation in a residual forearc basin of the Northeastern Pacific Rim: Cook Inlet, Alaska case study

    SciTech Connect

    Stricker, G.D.; Flores, R.M. )

    1996-01-01

    Cook Inlet in southern Alaska represents a Cenozoic residual forearc basin in a convergent continental margin, where the Pacific Plate is being subducted beneath the North American Plate. This basin accumulated the >6,700-m-thick, mainly nonmarine, Eocene-Pliocene Kenai Group. These rocks contain biogenic coal-bed methane estimated to be as high as 245 TCF. Lignites to subbituminous coals with subsurface R[sub o] ranging from 0.38 to 0.73 percent and the stage of clay-mineral diagenesis and expandibility indicate a thermally [open quotes]cool[close quotes] basin. Miocene Tyonek and Beluga Formations compose 65 percent (>4,300 m thick) of the Kenai Group. The Tyonek includes conglomeratic sandstones, siltstones, mudstones, coals, and carbonaceous shales, interpreted as braided- stream deposits. These fluvial deposits are interbecided with burrowed, lenticular, and flaser-bedded sandstones, siltstones, and mudstones, interpreted as tidal deposits. Tyonek framework conglomerates formed in wet alluvial fans incised on paleovalleys of the Chugach terrane. Coal-forming mires are well developed on abandoned braided-stream deposits. Tyonek drainages formed in high-gradient alluvial plains inundated by tides similar to environments in the modern upper Cook Inlet. The upper Miocene Beluga consists of sandstones, siltstones, mudstones, carbonaceous shales, and coals deposited in meandering (low sinuosity) and anastomosed fluvial systems. These fluvial deposits alternated vertically with deposits of coal-forming mires. The Beluga drainages formed in low-gradient alluvial plains. The high-gradient Tyonek alluvial plain was probably controlled by provenance uplift and eustatic change, whereas the low-gradient Beluga alluvial plain was influenced by subdued provenance uplift and rapid basin subsidence. Rapid sedimentation on both these low- and high-gradient alluvial plains, which kept up with subsidence, produced a thermally [open quotes]cool[close quotes] basin.

  2. Miocene fluvial-tidal sedimentation in a residual forearc basin of the Northeastern Pacific Rim: Cook Inlet, Alaska case study

    SciTech Connect

    Stricker, G.D.; Flores, R.M.

    1996-12-31

    Cook Inlet in southern Alaska represents a Cenozoic residual forearc basin in a convergent continental margin, where the Pacific Plate is being subducted beneath the North American Plate. This basin accumulated the >6,700-m-thick, mainly nonmarine, Eocene-Pliocene Kenai Group. These rocks contain biogenic coal-bed methane estimated to be as high as 245 TCF. Lignites to subbituminous coals with subsurface R{sub o} ranging from 0.38 to 0.73 percent and the stage of clay-mineral diagenesis and expandibility indicate a thermally {open_quotes}cool{close_quotes} basin. Miocene Tyonek and Beluga Formations compose 65 percent (>4,300 m thick) of the Kenai Group. The Tyonek includes conglomeratic sandstones, siltstones, mudstones, coals, and carbonaceous shales, interpreted as braided- stream deposits. These fluvial deposits are interbecided with burrowed, lenticular, and flaser-bedded sandstones, siltstones, and mudstones, interpreted as tidal deposits. Tyonek framework conglomerates formed in wet alluvial fans incised on paleovalleys of the Chugach terrane. Coal-forming mires are well developed on abandoned braided-stream deposits. Tyonek drainages formed in high-gradient alluvial plains inundated by tides similar to environments in the modern upper Cook Inlet. The upper Miocene Beluga consists of sandstones, siltstones, mudstones, carbonaceous shales, and coals deposited in meandering (low sinuosity) and anastomosed fluvial systems. These fluvial deposits alternated vertically with deposits of coal-forming mires. The Beluga drainages formed in low-gradient alluvial plains. The high-gradient Tyonek alluvial plain was probably controlled by provenance uplift and eustatic change, whereas the low-gradient Beluga alluvial plain was influenced by subdued provenance uplift and rapid basin subsidence. Rapid sedimentation on both these low- and high-gradient alluvial plains, which kept up with subsidence, produced a thermally {open_quotes}cool{close_quotes} basin.

  3. Comparison of earthquake-triggered turbidites from the Saguenay (Eastern Canada) and Reloncavi (Chilean margin) Fjords: Implications for paleoseismicity and sedimentology

    NASA Astrophysics Data System (ADS)

    St-Onge, Guillaume; Chapron, Emmanuel; Mulsow, Sandor; Salas, Marcos; Viel, Matias; Debret, Maxime; Foucher, Anthony; Mulder, Thierry; Winiarski, Thierry; Desmet, Marc; Costa, Pedro J. M.; Ghaleb, Bassam; Jaouen, Alain; Locat, Jacques

    2012-01-01

    High-resolution seismic profiles along with physical and sedimentological properties of sediment cores from the Saguenay (Eastern Canada) and Reloncavi (Chile) Fjords allowed the identification of several decimeter to meter-thick turbidites. In both fjords, the turbidites were associated with large magnitude historic and pre-historic earthquakes including the 1663 AD (M > 7) earthquake in the Saguenay Fjord, and the 1960 (M 9.5), 1837 (M ~ 8) and 1575 AD major Chilean subduction earthquakes in the Reloncavi Fjord. In addition, a sand layer with exoscopic characteristics typical of a tsunami deposit was observed immediately above the turbidite associated with the 1575 AD earthquake in the Reloncavi Fjord and supports both the chronology and the large magnitude of that historic earthquake. In the Saguenay Fjord, the earthquake-triggered turbidites are sometimes underlying a hyperpycnite associated with the rapid breaching and draining of a natural dam formed by earthquake-triggered landslides. Similar hyperpycnal floods were also recorded in historical and continental geological archives for the 1960 and 1575 AD Chilean subduction earthquakes, highlighting the risk of such flood events several weeks or months after main earthquake. In both fjords, as well as in other recently recognized earthquake-triggered turbidites, the decimeter-to meter-thick normally-graded turbidites are characterized by a homogeneous, but slightly fining upward tail. Finally, this paper also emphasizes the sensitivity of fjords to record historic and pre-historic seismicity.

  4. Sediment delivery to the Gulf of Alaska: source mechanisms along a glaciated transform margin

    USGS Publications Warehouse

    Dobson, M.R.; O'Leary, D.; Veart, M.

    1998-01-01

    Sediment delivery to the Gulf of Alaska occurs via four areally extensive deep-water fans, sourced from grounded tidewater glaciers. During periods of climatic cooling, glaciers cross a narrow shelf and discharge sediment down the continental slope. Because the coastal terrain is dominated by fjords and a narrow, high-relief Pacific watershed, deposition is dominated by channellized point-source fan accumulations, the volumes of which are primarily a function of climate. The sediment distribution is modified by a long-term tectonic translation of the Pacific plate to the north along the transform margin. As a result, the deep-water fans are gradually moved away from the climatically controlled point sources. Sets of abandoned channels record the effect of translation during the Plio-Pleistocene.

  5. Accretion of southern Alaska

    USGS Publications Warehouse

    Hillhouse, J.W.

    1987-01-01

    Paleomagnetic data from southern Alaska indicate that the Wrangellia and Peninsular terranes collided with central Alaska probably by 65 Ma ago and certainly no later than 55 Ma ago. The accretion of these terranes to the mainland was followed by the arrival of the Ghost Rocks volcanic assemblage at the southern margin of Kodiak Island. Poleward movement of these terranes can be explained by rapid motion of the Kula oceanic plate, mainly from 85 to 43 Ma ago, according to recent reconstructions derived from the hot-spot reference frame. After accretion, much of southwestern Alaska underwent a counterclockwise rotation of about 50 ?? as indicated by paleomagnetic poles from volcanic rocks of Late Cretaceous and Early Tertiary age. Compression between North America and Asia during opening of the North Atlantic (68-44 Ma ago) may account for the rotation. ?? 1987.

  6. USGS Alaska State Mosaic

    USGS Publications Warehouse

    ,

    2008-01-01

    The Alaska State Mosaic consists of portions of scenes from the Multi-Resolution Land Characteristics 2001 (MRLC 2001) collection. The 172 selected scenes have been geometrically and radiometrically aligned to produce a seamless, relatively cloud-free image of the State. The scenes were acquired between July 1999 and September 2002, resampled to 120-meter pixels, and cropped to the State boundary. They were reprojected into a standard Alaska Albers projection with the U.S. National Elevation Dataset (NED) used to correct for relief.

  7. A New Ice-sheet / Ocean Interaction Model for Greenland Fjords using High-Order Discontinuous Galerkin Methods

    NASA Astrophysics Data System (ADS)

    Kopera, M. A.; Maslowski, W.; Giraldo, F.

    2015-12-01

    One of the key outstanding challenges in modeling of climate change and sea-level rise is the ice-sheet/ocean interaction in narrow, elongated and geometrically complicated fjords around Greenland. To address this challenge we propose a new approach, a separate fjord model using discontinuous Galerkin (DG) methods, or FDG. The goal of this project is to build a separate, high-resolution module for use in Earth System Models (ESMs) to realistically represent the fjord bathymetry, coastlines, exchanges with the outside ocean, circulation and fine-scale processes occurring within the fjord and interactions at the ice shelf interface. FDG is currently at the first stage of development. The DG method provides FDG with high-order accuracy as well as geometrical flexibility, including the capacity to handle non-conforming adaptive mesh refinement to resolve the processes occurring near the ice-sheet/ocean interface without introducing prohibitive computational costs. Another benefit of this method is its excellent performance on multi- and many-core architectures, which allows for utilizing modern high performance computing systems for high-resolution simulations. The non-hydrostatic model of the incompressible Navier-Stokes equation will account for the stationary ice-shelf with sub-shelf ocean interaction, basal melting and subglacial meltwater influx and with boundary conditions at the surface to account for floating sea ice. The boundary conditions will be provided to FDG via a flux coupler to emulate the integration with an ESM. Initially, FDG will be tested for the Sermilik Fjord settings, using real bathymetry, boundary and initial conditions, and evaluated against available observations and other model results for this fjord. The overarching goal of the project is to be able to resolve the ice-sheet/ocean interactions around the entire coast of Greenland and two-way coupling with regional and global climate models such as the Regional Arctic System Model (RASM

  8. Environmental Evolution of a Small Antarctic Fjord Through the Recent Past

    NASA Astrophysics Data System (ADS)

    Hass, H. C.; Wölfl, A. C.; Wittenberg, N.; Betzler, C.; Kuhn, G.

    2014-12-01

    Rapid regional warming at an increasing pace ever since the end of the Little Ice Age (c. AD 1900) causes significant change in the coastal marine environments of the West Antarctic Peninsula and beyond. A comprehensive set of hydroacoustic ground-discrimination data (RoxAnn GDX) was gathered to develop a high resolution characterization of the seafloor habitats in the Potter Cove, King George Island, a small fjord with a retreating former tidewater glacier at its head. Sediment samples and underwater video footage are used for ground truthing. Seven habitat zones are distinguished. These include the shallow high-energy wave zone exposing unvegetated rocks to the low-energy deeper basins characterized by muddy sediments and the typical biota including ophiuroids, ascidians, sponges, sea pens. The results allow to subdivide the Potter Cove into a "dynamic zone" (DZ) with rocks and mixed fine sediments covering the inner cove, a large transition zone that we call the "subrecent zone" (SZ) buried under fine meltwater sediments and the "quasi persistent zone" (QPZ) that reveals more mature conditions in many aspects further downfjord. These zones represent development stages resulting from the increasing distance to and decreasing influence of the glacier front. The DZ is trailing directly behind the retreating glacier front. As long as there is strong discharge of sediment-loaded meltwater the DZ transitions into the SZ after a period of time (under recent conditions: decades) which itself transitions into the QPZ after centuries. We assume that during the Medieval Warm Period (c. AD 800-1350) the glacier terminus was at or even behind its present position. Until the maximum of the Little Ice Age the glacier advanced to form a prominent moraine complex. Ever since the glacier retreated at increasing speed to its recent position. If the warming trend continues the glacier will retreat further away from the fjord head and the QPZ will likely cover the entire fjord after

  9. Greenland Ice Sheet nutrient export: Towards a reaction-transport model of fjord dynamics

    NASA Astrophysics Data System (ADS)

    Crosby, James; Arndt, Sandra; Wadham, Jemma; Bingham, Rory

    2015-04-01

    Glacial runoff has the potential to deliver large quantities of dissolved and particulate bioavailable nutrients to surrounding marine environments. The marine waters bordering the Greenland Ice Sheet (GrIS) host some of the most productive ecosystems in the world, and possess high socio-economic value from fisheries. Furthermore, the productivity of phytoplankton in the North Atlantic sequesters CO2 from the atmosphere with a potentially important effect on the global coastal ocean CO2 budget. Providing a link between glacier and coastal ocean, fjords are critical components of the marine coastal system in this region, acting as both transfer routes and sinks for glacial nutrient export. As such they have the potential to act as significant biogeochemical processors, yet are currently underexplored. We propose to close this knowledge gap by developing a coupled 2D physical-biogeochemical model of the Godthåbsfjord system to quantitatively assess the impact of nutrients exported from the GrIS on fjord primary productivity and biogeochemical dynamics. Here, we present the first results of the hydrodynamic model. Hydrodynamic circulation patterns and freshwater transit times are explored to provide a first understanding of the glacier-fjord-ocean continuum. The hydrodynamic model will be dynamically coupled to a biogeochemical model with the view to providing a comprehensive understanding of the fate of nutrients exported from the GrIS. This will be extended to address the future sensitivity of these coastal systems to a warming climate, knowledge of which is critical when assessing the role of these dynamic and unique environments.

  10. Spatial structure of the meroplankton community along a Patagonian fjord - The role of changing freshwater inputs

    NASA Astrophysics Data System (ADS)

    Meerhoff, Erika; Tapia, Fabián J.; Castro, Leonardo R.

    2014-12-01

    Freshwater inputs are major drivers of circulation, hydrographic structure, and productivity patterns along estuarine systems. We assessed the degree to which meroplankton community structure in the Baker/Martinez fjord complex (Chilean Patagonia, 47.5°S) responds to spatial and temporal changes in hydrographic conditions driven by seasonal changes in Baker river outflow. Zooplankton and hydrographic measurements were conducted along the fjord in early spring (October) and late summer (February), when river outflow was minimal and maximal, respectively. Major meroplankton groups found on these surveys were larval barnacles, crabs, bivalves and gastropods. There was a clear change in community structure between October and February, explained by a switch in the numerically dominant group from barnacle to bivalve larvae. This change in community structure was related to changes in hydrographic structure along the fjord, which are mainly associated with seasonal changes in the Baker river outflow. A variance partition analysis showed no significant spatial trend that could account for the variation in meroplankton along the Martinez channel, whereas temporal variability and environmental variables accounted for 36.6% and 27.6% of the variance, respectively. When comparing meroplankton among the Baker and Martinez channels in October, changes in environmental variables explained 44.9% of total variance, whereas spatial variability accounted for 23.5%. Early and late-stage barnacle larvae (i.e. nauplii and cyprids) were more abundant in water with lower temperature, and higher dissolved oxygen and chlorophyll-a concentration, whereas bivalve larvae were more strongly associated to warmer waters. The seasonal shift in numerical dominance, from barnacle larvae in early spring to bivalve larvae in late summer, suggests that reproduction of these groups is triggered by substantially different sets of conditions, both in terms of hydrography and food availability. The

  11. Transient river flow into a fjord and its control of plume energy partitioning

    NASA Astrophysics Data System (ADS)

    O'Callaghan, J. M.; Stevens, C. L.

    2015-05-01

    The influence of variable inflows on near-field plume dynamics and energy partitioning was examined using observations of a controlled flow into Doubtful Sound, New Zealand. The high temporal changes in flows passing through the Manapouri hydroelectric power station mimic the magnitude and variability seen in small mountainous river systems (SMRS) globally. The variable flow coupled with strong vertical density gradients akin to ambient conditions in coastal systems enabled plume behavior to be characterized for differing flow, wind, and tidal inputs in a quasi-idealized "laboratory" system. Comparisons of the frequency distributions of energy for different forcing conditions showed that baroclinic and barotropic processes were closely intertwined for transient forcing. The periodicity of density due to tidal oscillations was initially absent; headwaters of the fjord absorbed the momentum when inflows were substantially increased from the mean of ˜420 m3 s-1. From the buoyancy frequency squared N2, six events were identified when N2 was greater than 0.07 s-2. Seven occurrences of supercritical flow (Froude number, Fri > 1) and associated transitions to subcritical flow were observed over the duration of mooring deployment. Transient inflows induced internal hydraulic jumps in the near-field region which lead to a rapid breakdown of vertical stratification. The horizontal length scale of an internal hydraulic jump is O (1 km). Not all transitions from Fri > 1 to <1 are explained by transient forcing and the role of strong, up-fjord wind stress is likely to initiate supercritical flows via setup at the head of the fjord.

  12. Glacial history of sub-Antarctic South Georgia based on the submarine geomorphology of its fjords

    NASA Astrophysics Data System (ADS)

    Hodgson, Dominic A.; Graham, Alastair G. C.; Griffiths, Huw J.; Roberts, Stephen J.; Cofaigh, Colm O.; Bentley, Michael J.; Evans, David J. A.

    2014-05-01

    We present multibeam swath bathymetric surveys of the major fjords surrounding the sub-Antarctic island of South Georgia to characterise the glacial geomorphology and to identify the relative timings and extent of past glacial advance and retreat. Bathymetry data revealed a range of glacial features including terminal, retreat and truncated moraines, deep (distal) outer and shallow (proximal) inner basins and cross shelf troughs. These provide evidence of glacial advance and retreat through several glacial cycles. A near consistent pattern of large scale submarine geomorphological features was observed in the different fjords suggesting a similar response of margins of the island ice cap to past climate forcing. A relative chronology based on the relationships between the submarine features with their radiocarbon and cosmogenic isotope dated terrestrial counterparts suggests that widely observed inner basin moraines date from the last major glacial advance or Last Glacial Maximum, while deep basin moraines may date from an earlier (pre-LGM) more extensive glaciation, which we speculate corresponds to MIS6. On the sides of the deep basins a series of truncated moraines show ice advance positions from preceding glacial periods. The cross shelf troughs, and mid-trough moraines are interpreted as the product of much more extensive glaciations that predate the fjord geomorphology mapped here, thus possibly older than MIS6. This hypothesis would suggest that South Georgia followed a glacial history similar to that of central Patagonia (46deg S)where a series of Pleistocene glaciations (of MIS 20 and younger) extended beyond LGM limits, with the most extensive glacial advance occurring at c. 1.1 Ma.

  13. Glacial history of sub-Antarctic South Georgia based on the submarine geomorphology of its fjords

    NASA Astrophysics Data System (ADS)

    Hodgson, Dominic A.; Graham, Alastair G. C.; Griffiths, Huw J.; Roberts, Stephen J.; Cofaigh, Colm Ó.; Bentley, Michael J.; Evans, David J. A.

    2014-04-01

    We present multibeam swath bathymetric surveys of the major fjords surrounding the sub-Antarctic island of South Georgia to characterise the glacial geomorphology and to identify the relative timings and extent of past glacial advance and retreat. Bathymetry data revealed a range of glacial features including terminal, retreat and truncated moraines, deep (distal) outer and shallow (proximal) inner basins and cross shelf troughs. These provide evidence of glacial advance and retreat through several glacial cycles. A near consistent pattern of large scale submarine geomorphological features was observed in the different fjords suggesting a similar response of margins of the island ice cap to past climate forcing. A relative chronology based on the relationships between the submarine features with their radiocarbon and cosmogenic isotope dated terrestrial counterparts suggests that widely observed inner basin moraines date from the last major glacial advance or Last Glacial Maximum, while deep basin moraines may date from an earlier (pre-LGM) more extensive glaciation, which we speculate corresponds to MIS6. On the sides of the deep basins a series of truncated moraines show ice advance positions from preceding glacial periods. The cross shelf troughs, and mid-trough moraines are interpreted as the product of much more extensive glaciations that predate the fjord geomorphology mapped here, thus possibly older than MIS6. This hypothesis would suggest that South Georgia followed a glacial history similar to that of central Patagonia (46°S) where a series of Pleistocene glaciations (of MIS 20 and younger) extended beyond LGM limits, with the most extensive glacial advance occurring at c. 1.1 Ma.

  14. Sea floor gouges and pits in deep fjords, Baffin Island: Possible mammalian feeding traces

    NASA Astrophysics Data System (ADS)

    Hein, F. J.; Syvitski, J. P. M.

    1989-06-01

    Pisces submersible dives within Baffin Island fjords have revealed the common occurrence of pits on the sea floor, at water depths between 40 and 326 m. The size of these pits are in the decimeter to meter range. Through indirect evidence (by comparison of morphologic features to pits or gouges of known origin) they are believed to be feeding traces of narwhal, beluga, or bowhead whales. If so, they are the deepest mammalian feeding traces yet reported. Bioerosion by large foraging mammals may be a more common sea floor process than previously thought.

  15. Seasonal fluctuations in macrobenthic fauna of the Fucus belt in kiel fjord (western baltic sea)

    NASA Astrophysics Data System (ADS)

    Anders, K.; Möller, H.

    1983-09-01

    The macrobenthic fauna associated with Fucus at a station in the Kiel Fjord was investigated from June 1978 until June 1979. The predominant group in number as well as in biomass were gammarids. They formed, together with the isopods Idotea spp., approximately 95 % of the total average annual biomass. The total dry weight of all macrobenthic animals (excl. Littorina spp.) increased from 1.9 g per kg Fucus in May to about 16 g in June August, and dropped to 8.3 g in September. Winter average dry weight values were only about 6 % of the summer values.

  16. Oceanographic Processes in Chilean Fjords of Patagonia: From small to large-scale studies

    NASA Astrophysics Data System (ADS)

    Iriarte, José L.; Pantoja, Silvio; Daneri, Giovanni

    2014-12-01

    Subantarctic ecosystems, such as the inner shelf of southern Chile (41-55°S), are characterized by a complex system of fjords, channels, gulf, estuaries, bays, and are affected by physical regimes that may strongly modulate biological productivity. Rhythms and rates of primary production in these highly fluctuating fjord environments depend to a large extent on the timing and magnitude of nutrient supply and light availability for primary producers. In such complex fjord systems, the interaction between oceanic waters and freshwater from multiple sources (e.g., rivers, surface and groundwater runoff, snow/glacier melting, and precipitation) produces strong vertical and horizontal gradients in salinity, density, organic and inorganic nutrient ratios and light availability (Pickard, 1971; Dávila et al., 2002; Silva and Palma 2006; Jacob et al., 2014). The vertical structure of the water column (stratified/mixed), modulated by the seasonal and inter-annual changes of the pycnocline may affect biomass and composition of pelagic and benthic assemblages, and ultimately spatial and temporal patterns of carbon fluxes (the 'Biological Pump'), and biogeochemical balances in this large region. In addition, the region is particularly vulnerable to climate change and anthropogenic influences (Iriarte et al., 2010). Remote and large-scale climatic-oceanographic phenomena (e.g., ENSO and Southern Annular Mode) and global climate trends may alter freshwater discharge of large rivers such as the Puelo and Palena, as has also been suggested for the Baker River located between Patagonian Ice fields and other northern fjords shown by paleo-oceanographic (Sepúlveda et al., 2009; Rebolledo et al., 2011) and dendrochronological studies (Lara et al., 2008). Although changes in climate are expected to alter the regional atmospheric forcing such as the West Wind Drift (Quintana and Aceituno, 2012; Garreaud et al., 2013) and the local ocean circulation in this region, including the

  17. Macroalgae contribute to nested mosaics of pH variability in a subarctic fjord

    NASA Astrophysics Data System (ADS)

    Krause-Jensen, D.; Duarte, C. M.; Hendriks, I. E.; Meire, L.; Blicher, M. E.; Marbà, N.; Sejr, M. K.

    2015-08-01

    The Arctic Ocean is considered the most vulnerable ecosystem to ocean acidification, and large-scale assessments of pH and the saturation state for aragonite (Ωarag) have led to the notion that the Arctic Ocean is already close to a corrosive state. In high-latitude coastal waters the regulation of pH and Ωarag is, however, far more complex than offshore because increased biological activity and input of glacial meltwater affect pH. Effects of ocean acidification on calcifiers and non-calcifying phototrophs occupying coastal habitats cannot be derived from extrapolation of current and forecasted offshore conditions, but they require an understanding of the regimes of pH and Ωarag in their coastal habitats. To increase knowledge of the natural variability in pH in the Arctic coastal zone and specifically to test the influence of benthic vegetated habitats, we quantified pH variability in a Greenland fjord in a nested-scale approach. A sensor array logging pH, O2, PAR, temperature and salinity was applied on spatial scales ranging from kilometre scale across the horizontal extension of the fjord; to 100 m scale vertically in the fjord, 10-100 m scale between subtidal habitats with and without kelp forests and between vegetated tidal pools and adjacent vegetated shores; and to centimetre to metre scale within kelp forests and millimetre scale across diffusive boundary layers of macrophyte tissue. In addition, we assessed the temporal variability in pH on diurnal and seasonal scales. Based on pH measurements combined with point samples of total alkalinity, dissolved inorganic carbon and relationships to salinity, we also estimated variability in Ωarag. Results show variability in pH and Ωarag of up to 0.2-0.3 units at several scales, i.e. along the horizontal and vertical extension of the fjord, between seasons and on a diel basis in benthic habitats and within 1 m3 of kelp forest. Vegetated intertidal pools exhibited extreme diel pH variability of > 1.5 units and

  18. Macroalgae contribute to nested mosaics of pH variability in a sub-Arctic fjord

    NASA Astrophysics Data System (ADS)

    Krause-Jensen, D.; Duarte, C. M.; Hendriks, I. E.; Meire, L.; Blicher, M. E.; Marbà, N.; Sejr, M. K.

    2015-03-01

    The Arctic Ocean is considered the most vulnerable ecosystem to ocean acidification (OA) and large-scale assessments of pH and the saturation state for aragonite (Ωarag) indicate that it is already close to corrosive states (Ωarag < 1). In high-latitude coastal waters the regulation of pH and Ωarag is far more complex than offshore because increased biological activity and input of glacial meltwater affect pH. As most calcifiers occupy coastal habitats, the assessment of risks from OA to these vulnerable organisms cannot be derived from extrapolation of current and forecasted offshore conditions, but requires an understanding of the regimes of pH and Ωarag in their coastal habitats. To increase knowledge of the natural variability of pH in the Arctic coastal zone and specifically to test the influence of benthic vegetated habitats, we quantified pH-variability in a Greenland fjord in a nested scale approach. A sensor array logging pH, O2, PAR, temperature and salinity was applied on spatial scales ranging from km-scale across the horizontal extension of the fjord, over 100 m scale vertically in the fjord, 10-100 m scale between subtidal habitats with and without kelp forests and between vegetated tidal pools and adjacent vegetated shores, to cm-m scale within kelp forests and mm-scale across boundary layers of macrophyte tissue. In addition, we assessed the temporal variability in pH on diurnal and seasonal scales. Based on pH-measurements combined with relationships between salinity, total alkalinity and dissolved inorganic carbon we also estimated variability of Ωarag. Results show variability in pH and Ωarag of up to 0.2-0.3 units at several scales, i.e. along the horizontal and vertical extension of the fjord, between seasons and on a diel basis in benthic habitats and within 1 m3 of kelp forest. Vegetated intertidal pools exhibited extreme diel pH variability of > 1.5 units and macrophyte boundary layers a pH-range of up to 0.8 units. Overall, Ωarag was

  19. Reconstructing Holocene changes in the Southern Hemisphere westerly winds: Integrating modern processes and paleoclimate data from New Zealand's southern fjords

    NASA Astrophysics Data System (ADS)

    Hinojosa, J.; Moy, C. M.; Wilson, G. S.; Stirling, C. H.

    2013-12-01

    The Southern Hemisphere westerly winds are an important component of the global carbon cycle due to their influence on Southern Ocean CO2 flux. In addition, the winds influence mid-latitude storm tracks, thereby controlling moisture balance over much of New Zealand's South Island and other Southern Hemisphere regions. Fiordland, New Zealand is an ideal locale to investigate Holocene changes in westerly wind behavior: It sits at the northern margin of the wind field maximum, is sensitive to latitudinal and strength fluctuations of the winds, and is the location of numerous fjord sub-basins with high sedimentation rates (up to 3 mm/yr). Due to the strong positive relationship between wind speed and regional rainfall, reconstructions of past precipitation and fjord circulation can inform us of past westerly wind behavior. These processes can be observed through changes in the rate of organic carbon delivery from land: When precipitation is high, more terrestrial organic carbon is delivered to the fjords, while low precipitation shifts the balance toward accumulation of marine organic carbon. An important first step towards reconstructing past westerly wind variability is to characterize the distribution and cycling of carbon throughout different depositional settings in the fjords to determine the optimal location for the development of paleoclimate records. Here, we present a geochemical characterization of surface sediments and the water column throughout the region and apply this understanding to sediment cores. During three field seasons in 2012 and 2013, we collected surface sediments, particulate organic matter, and piston cores from 10 different fjords spanning 44-46° S. Our results suggest that organic carbon in the fjord basins largely follows a two-end-member mixing model, drawing from marine and terrestrial end-member sources. We see consistent down-fjord trends in carbon and nitrogen concentrations and isotopes measured from surface sediments and

  20. A hydrologically inspired approach to predicting fjord bedrock elevation at the ice-ocean interface of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Williams, Chris; Bamber, Jonathan; Cochran, James; Cornford, Stephen; Dowdeswell, Julian; Jordan, Tom; Morlighem, Mathieu; Palmer, Steven; Siegert, Martin; Tinto, Kirsty; Paden, John

    2016-04-01

    Measurements of ice sheet basal topography provide vital boundary conditions for numerical modelling of ice sheet evolution and are key to understanding observations of ice sheet dynamics. A consistent issue with existing bed topography products for the Greenland Ice Sheet - developed using ice thickness observations from ice penetrating radar, interpolation, and mass conservation (Bamber et al., 2013, Morlighem et al., 2014) - is the poor quantification of near coastal bathymetry. Accurate mapping of bedrock elevation in these areas is important as glaciers local to these regions have been observed to have the largest velocities, greatest associated mass changes, and are therefore most sensitive to uncertainties in basal boundary conditions when modelling ice motion (e.g. Nick et al., 2013). Sparse data availability and resultant coarse rendering of digital elevation products at the edges of existing ice sheet bed elevation products poses issues, particularly when integrating models over longer periods of time (e.g. Vieli and Nick, 2011). Improving data coverage in these regions is a further priority as fjord bathymetry is known to provide a strong control on ocean circulation and ice-ocean forcing (e.g. Straneo et al., 2011) which have been related to changes observed in tidewater glacier systems (e.g. Murray et al., 2010). We have developed a method that improves existing products of the Greenland Ice Sheet bed rock and surrounding bathymetry through [1] the addition of new bathymetric and ice thickness data where available and [2] the integration of generalised fjord structures in data sparse regions to better inform interpolation routines. Following the release of the last Greenland bed topography-bathymetry product (Bamber et al., 2013), new data acquired through gravity inversion as well as single and multi-beam echo sounding are included, improving bed elevation data density and coverage. In fjords which remain data sparse, idealised fjord geometry is

  1. Alaska Glaciers and Rivers

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image on October 7, 2007, showing the Alaska Mountains of south-central Alaska already coated with snow. Purple shadows hang in the lee of the peaks, giving the snow-clad land a crumpled appearance. White gives way to brown on the right side of the image where the mountains yield to the lower-elevation Susitna River Valley. The river itself cuts a silver, winding path through deep green forests and brown wetlands and tundra. Extending from the river valley, are smaller rivers that originated in the Alaska Mountains. The source of these rivers is evident in the image. Smooth white tongues of ice extend into the river valleys, the remnants of the glaciers that carved the valleys into the land. Most of the water flowing into the Gulf of Alaska from the Susitna River comes from these mountain glaciers. Glacier melt also feeds glacier lakes, only one of which is large enough to be visible in this image. Immediately left of the Kahiltna River, the aquamarine waters of Chelatna Lake stand out starkly against the brown and white landscape.

  2. Alaska Mathematics Standards

    ERIC Educational Resources Information Center

    Alaska Department of Education & Early Development, 2012

    2012-01-01

    High academic standards are an important first step in ensuring that all Alaska's students have the tools they need for success. These standards reflect the collaborative work of Alaskan educators and national experts from the nonprofit National Center for the Improvement of Educational Assessment. Further, they are informed by public…

  3. Suicide in Northwest Alaska.

    ERIC Educational Resources Information Center

    Travis, Robert

    1983-01-01

    Between 1975 and 1979 the Alaskan Native suicide rate (90.9 per 100,000) in Northwest Alaska was more than seven times the national average. Alienation, loss of family, low income, alcohol abuse, high unemployment, and more education were factors related to suicidal behavior. Average age for suicidal behavior was 22.5. (Author/MH)

  4. Alaska's Young Entrepreneurs.

    ERIC Educational Resources Information Center

    Knapp, Marilyn R.

    1989-01-01

    Describes Edgecumbe Enterprises, a four-year-old fish exporting venture run by Mt. Edgecumbe High School in Sitka, Alaska, and the students' meeting with business leaders in Tokyo, Japan. The young entrepreneurs spent two weeks studying the Japanese marketing structure. (JOW)

  5. Seismology Outreach in Alaska

    NASA Astrophysics Data System (ADS)

    Gardine, L.; Tape, C.; West, M. E.

    2014-12-01

    Despite residing in a state with 75% of North American earthquakes and three of the top 15 ever recorded, most Alaskans have limited knowledge about the science of earthquakes. To many, earthquakes are just part of everyday life, and to others, they are barely noticed until a large event happens, and often ignored even then. Alaskans are rugged, resilient people with both strong independence and tight community bonds. Rural villages in Alaska, most of which are inaccessible by road, are underrepresented in outreach efforts. Their remote locations and difficulty of access make outreach fiscally challenging. Teacher retention and small student bodies limit exposure to science and hinder student success in college. The arrival of EarthScope's Transportable Array, the 50th anniversary of the Great Alaska Earthquake, targeted projects with large outreach components, and increased community interest in earthquake knowledge have provided opportunities to spread information across Alaska. We have found that performing hands-on demonstrations, identifying seismological relevance toward career opportunities in Alaska (such as natural resource exploration), and engaging residents through place-based experience have increased the public's interest and awareness of our active home.

  6. Current Ethnomusicology in Alaska.

    ERIC Educational Resources Information Center

    Johnston, Thomas F.

    The systematic study of Eskimo, Indian, and Aleut musical sound and behavior in Alaska, though conceded to be an important part of white efforts to foster understanding between different cultural groups and to maintain the native cultural heritage, has received little attention from Alaskan educators. Most existing ethnomusical studies lack one or…

  7. Alaska's Cold Desert.

    ERIC Educational Resources Information Center

    Brune, Jeff; And Others

    1996-01-01

    Explores the unique features of Alaska's Arctic ecosystem, with a focus on the special adaptations of plants and animals that enable them to survive in a stressful climate. Reviews the challenges facing public and private land managers who seek to conserve this ecosystem while accommodating growing demands for development. Includes classroom…

  8. Venetie, Alaska energy assessment.

    SciTech Connect

    Jensen, Richard Pearson; Baca, Michael J.; Schenkman, Benjamin L.; Brainard, James Robert

    2013-07-01

    This report summarizes the Energy Assessment performed for Venetie, Alaska using the principals of an Energy Surety Microgrid (ESM) The report covers a brief overview of the principals of ESM, a site characterization of Venetie, a review of the consequence modeling, some preliminary recommendations, and a basic cost analysis.

  9. Reconnaissance geology, mineral occurrences, and geochemical anomalies of the Yentna district, Alaska

    USGS Publications Warehouse

    Clark, Allen L.; Hawley, C.C.

    1968-01-01

    The Yentna district, in south-central Alaska, is underlain by slightly metamorphosed Mesozoic sedimentary rocks, and by sandstones, conglomerates and coaly minerals of the Tertiary Kenai Formation. The bedrock is locally covered by extensive surficial deposits of Quaternary and Recent (Holocene) age. The Mesozoic strata are cut by a quartz monzonite batholith in the Tokositna Mountains and by alaskitic dikes and plugs in the Peters and Dutch Hills. A silica-carbonate dike, which formed by alteration of a mafic or ultramafic dike, was noted in the Peters Hills. The major ore deposits are gold placer deposits of several types, including stream and bench deposits of Recent (Holocene) age, glacial-fluviatile deposits of Quaternary age, and conglomerates of Tertiary age. Quartz-rich conglomerates and breccias have also been productive and are interesting and controversial genetically. The present study indicates that they are closely related to shear zones containing quartz veins and highly altered rocks; previously the origin of the associated altered rocks had been ascribed to deep weathering. The report also contains descriptions of a few gold lode prospects and of geochemically anomalous areas such as those at Bunco Creek and near Mount Goldie.

  10. 76 FR 36573 - Public Land Order No. 7770; Extension of Public Land Order No. 6884; Alaska

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    .... 1714, it is ordered as follows: Public Land Order No. 6884 (56 FR 49847 (1991)), as corrected (56 FR... Kenai River Recreation Area, the Russian River Campground Area, and the Lower Russian Lake Recreation... the recreational values of the Kenai River Recreation Area, the Russian River Campground Area, and...

  11. Microbial life in a fjord: metagenomic analysis of a microbial mat in Chilean patagonia.

    PubMed

    Ugalde, Juan A; Gallardo, Maria J; Belmar, Camila; Muñoz, Práxedes; Ruiz-Tagle, Nathaly; Ferrada-Fuentes, Sandra; Espinoza, Carola; Allen, Eric E; Gallardo, Victor A

    2013-01-01

    The current study describes the taxonomic and functional composition of metagenomic sequences obtained from a filamentous microbial mat isolated from the Comau fjord, located in the northernmost part of the Chilean Patagonia. The taxonomic composition of the microbial community showed a high proportion of members of the Gammaproteobacteria, including a high number of sequences that were recruited to the genomes of Moritella marina MP-1 and Colwelliapsycherythraea 34H, suggesting the presence of populations related to these two psychrophilic bacterial species. Functional analysis of the community indicated a high proportion of genes coding for the transport and metabolism of amino acids, as well as in energy production. Among the energy production functions, we found protein-coding genes for sulfate and nitrate reduction, both processes associated with Gammaproteobacteria-related sequences. This report provides the first examination of the taxonomic composition and genetic diversity associated with these conspicuous microbial mat communities and provides a framework for future microbial studies in the Comau fjord. PMID:24015199

  12. Microbial Life in a Fjord: Metagenomic Analysis of a Microbial Mat in Chilean Patagonia

    PubMed Central

    Ugalde, Juan A.; Gallardo, Maria J.; Belmar, Camila; Muñoz, Práxedes; Ruiz-Tagle, Nathaly; Ferrada-Fuentes, Sandra; Espinoza, Carola; Allen, Eric E.; Gallardo, Victor A.

    2013-01-01

    The current study describes the taxonomic and functional composition of metagenomic sequences obtained from a filamentous microbial mat isolated from the Comau fjord, located in the northernmost part of the Chilean Patagonia. The taxonomic composition of the microbial community showed a high proportion of members of the Gammaproteobacteria, including a high number of sequences that were recruited to the genomes of Moritella marina MP-1 and Colwelliapsycherythraea 34H, suggesting the presence of populations related to these two psychrophilic bacterial species. Functional analysis of the community indicated a high proportion of genes coding for the transport and metabolism of amino acids, as well as in energy production. Among the energy production functions, we found protein-coding genes for sulfate and nitrate reduction, both processes associated with Gammaproteobacteria-related sequences. This report provides the first examination of the taxonomic composition and genetic diversity associated with these conspicuous microbial mat communities and provides a framework for future microbial studies in the Comau fjord. PMID:24015199

  13. Controlling factors on productivity and size abundance distribution of phytoplankton in Patagonian fjords

    NASA Astrophysics Data System (ADS)

    Cuevas, L. A.; Iriarte, J. L.; Gonzalez, H.; Silva, N.; Vargas, C.

    2012-12-01

    Temperature and resource availability has been suggested to play an important role controlling phytoplankton size structure and productivity. Here we used five independent research cruisers covering the entire Patagonian fjords (41.5-56.0 degress latitude South) to conduct a comparative analysis between zones and to determine the importance of the controlling factors. For the entire Patagonian area phytoplankton size structure seems independent from temperature, but varies with total phytoplankton biomass and productivity. Microphytoplankton contribute with more than 80% in high productivity waters (chlorophyll-a higher than 5 μg L-1) and picophytoplankton dominates when chlorophyll-a is lower than 1 μg L-1. In addition, NO3:Si(OH)4 ratio control phytoplankton size structure, where a large decrease in Si(OH)4 from north to south Patagonia (from 20 to 0.1 mM average, respectively) seems to be a major factor of control. Major and prolonged effects expected in fjord areas, such as anthropogenic eutrophication and global warning, may modify the observed relationships leading to important changes in the phytoplankton community and its ecological role.

  14. Increased Atlantic water intrusion and related changes in Kongsfjorden, an Arctic fjord

    NASA Astrophysics Data System (ADS)

    David, Divya; P, Krishnan K.

    2015-04-01

    Kongsfjorden, an open fjord in the north-west coast of Spitsbergen (Svalbard archipelago) in the Arctic region undergoes seasonal shift between Arctic and Atlantic characteristics with prominent physical as well as biogeochemical implications. The Atlantic waters reaches Kongsfjorden through the West Spitsbergen Current (WSC) and this Atlantic water in the WSC has shown considerable warming in the past decades. The observational data shows an interannual increase in the intrusion of Atlantic waters and resultant variability in the watermasses in Kongsfjorden during the summer/fall of 2011 to 2014. An earlier intrusion of Atlantic waters and a progressive warming of the fjord over the last four years show a corresponding decrease in the summer chlorophyll biomass and the winter time ice formation. Another feature noted was a sharp decline in the freshwater volume in Kongsfjorden over the years. The remote sensing data during the same period shows an increased northward surface advection of warm waters along the West Spitsbergen Current to the Arctic region that is relevant for the ice formation and can have larger physical as well as biochemical implications.

  15. Norwegian fjord sediments reveal NAO related winter temperature and precipitation changes of the past 2800 years

    NASA Astrophysics Data System (ADS)

    Faust, Johan C.; Fabian, Karl; Milzer, Gesa; Giraudeau, Jacques; Knies, Jochen

    2016-02-01

    The North Atlantic Oscillation (NAO) is the leading mode of atmospheric circulation variability in the North Atlantic region. Associated shifts of storm tracks, precipitation and temperature patterns affect energy supply and demand, fisheries and agricultural, as well as marine and terrestrial ecological dynamics. Long-term NAO records are crucial to better understand its response to climate forcing factors, and assess predictability and shifts associated with ongoing climate change. A recent study of instrumental time series revealed NAO as main factor for a strong relation between winter temperature, precipitation and river discharge in central Norway over the past 50 years. Here we compare geochemical measurements with instrumental data and show that primary productivity recorded in central Norwegian fjord sediments is sensitive to NAO variability. This observation is used to calibrate paleoproductivity changes to a 500-year reconstruction of winter NAO (Luterbacher et al., 2001). Conditioned on a stationary relation between our climate proxy and the NAO we establish a first high resolution NAO proxy record (NAOTFJ) from marine sediments covering the past 2800 years. The NAOTFJ shows distinct co-variability with climate changes over Greenland, solar activity and Northern Hemisphere glacier dynamics as well as climatically associated paleo-demographic trends. The here presented climate record shows that fjord sediments provide crucial information for an improved understanding of the linkages between atmospheric circulation, solar and oceanic forcing factors.

  16. Laboratory investigations of granular and hydrodynamic processes in tidewater glacial fjords

    NASA Astrophysics Data System (ADS)

    Cathles, Mac; Thompson, Oluwatoyin; Burton, Justin

    Accelerated warming in the past few decades has led to a dramatic increase in glacial activity. This is perhaps most apparent in tidewater glacial fjords, where gravitational flows from ice sheets are focused into narrow channels of thick, fast-flowing ice which terminate into the ocean. The result is a complex system involving both melting and iceberg calving which has a direct impact on the Earth's climate and sea level rise. However, there are numerous inherent difficulties in collecting field data from remote, ice-choked fjords. To address this, we use a laboratory scale model to measure aspects of tidewater glaciers which are not observable in nature. Our model has helped to uncover the source of glacial earthquakes, where floating, cubic-kilometer scaled icebergs capsize due to gravitational instability, and temporarily reverse the velocity of the glacier. In addition, we use our model to address two other important components of tidewater glaciers involving a granular ice mélange which applies stresses on the glacier, and the role of iceberg capsize in disrupting the stratified heat transport at the glacier's terminus. We acknowledge support from NSF DMR-1506446.

  17. Characterising iceberg scour in diamicton, Scoresby Sund fjord system, East Greenland

    NASA Astrophysics Data System (ADS)

    Linch, Lorna D.; Dowdeswell, Julian A.

    2014-05-01

    Icebergs are major components in shaping polar and sub-polar continental margins, fjords and lakes. When the keel of an iceberg exceeds water depth it ploughs through soft sea/lake sediments gouging out kilometre long scours, 100s of metres wide and tens of metres deep. Because the influence of iceberg scours on sediment is a critical factor when offshore structures (e.g. oil/gas pipelines, power cables) are installed, the surface morphology of iceberg scours on sea/lake beds is relatively well-documented. Less however, is known about sub-scour (i.e. below the sea/lake bed surface) deformation, which is critical to inform i) installation of offshore structures where iceberg scour presents a geohazard, and ii) palaeoenvironmental reconstruction e.g. past ice sheet dynamics, glacial margins, climate etc. Despite advances in numerical modelling and physical testing of sub-scour deformation, such methods are largely still in their infancy, and they are rarely validated using direct empirical evidence of sub-scour deformation. The aim of this research therefore is to macroscopically and microscopically (thin sections) identify the style and intensity of deformation by the ploughing action of iceberg keels in diamictic cores collected from sediments in the heavily iceberg scoured Scoresby Sund fjord system, offshore of East Greenland.

  18. Coastal Submesoscale Baroclinic Eddies in Cyclostrophic Balance in the Saguenay Fjord.

    NASA Astrophysics Data System (ADS)

    Livernoche, Alexandre; Bourgault, Daniel; Chavanne, Cédric; Galbraith, Peter

    2016-04-01

    Submesoscale baroclinic eddies in cyclostrophic balance were studied in the Saguenay fjord (Quebec, Canada) using mooring data, boat-based sampling and oblique images taken from the shore, obtained in 2013 and 2015. Cyclostrophic balance implies equilibrium between the centrifugal force and the pressure gradient, with negligible Coriolis effect. The shear between the strong ebb flow and the bathymetric obstacle of a cape in the fjord creates a front downstream from the cape, which in turn generates vortices that are hundreds of meters in diameter. Shipborne ADCP, echosounder and CTD transects across the front were measured in order to understand the eddy generation. The first observed vortex had a radius of ~175 m, a maximum horizontal velocity of 0.3 m/s, and was trapped above the pycnocline. The horizontal surface currents were determined using Particle Imagery Velocimetry (PIV) applied to successive georectified images. It was found that under some conditions, sea surface patterns can provide sufficiently clear information to quantitatively capture the eddy current field and its evolution over time. From these observations, the vertical vorticity field as well as the horizontal strain rate can be computed. These results, although preliminary, are promising for investigating horizontal eddy diffusion in coastal waters, as well as their parameterization in ocean.

  19. Simulating the uncertain effect of active carbon capping of a dioxin-polluted Norwegian fjord.

    PubMed

    Starrfelt, Jostein; Saloranta, Tuomo M

    2015-07-01

    Process-based multimedia models are frequently used to simulate the long-term impacts of pollutants and to evaluate potential remediation actions that can be put in place to improve or manage polluted marine environments. Many such models are detailed enough to encapsulate the different scales and processes relevant for various contaminants, yet still are tractable enough for analysis through established methods for uncertainty assessment. Inclusion and quantification of the uncertainty associated with local efficacy of remediation actions is of importance when the desired outcome in terms of human health concerns or environmental classification shows a nonlinear relationship with remediation effort. We present an updated fugacity-based environmental fate model set up to simulate the historical fate of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) in the Grenland fjords, in Norway. The model is parameterized using Bayesian inference and is then used to simulate the effect of capping parts of the polluted sediments with active carbon. Great care is taken in quantifying the uncertainty regarding the efficacy of the activated carbon cap to reduce the leaching of contaminants from the sediments. The model predicts that by capping selected parts of the fjord, biota will be classified as moderately polluted approximately a decade earlier than a natural remediation scenario. Our approach also illustrates the importance of incorporating uncertainty in local remediation efforts, as the biotic concentrations scale nonlinearly with remediation effort.

  20. Asthma and American Indians/Alaska Natives

    MedlinePlus

    ... Minority Population Profiles > American Indian/Alaska Native > Asthma Asthma and American Indians/Alaska Natives In 2014, 218, ... Native American adults reported that they currently have asthma. American Indian/Alaska Native children are 30% more ...

  1. Numerical study of tsunami generated by multiple submarine slope failures in Resurrection Bay, Alaska, during the MW 9.2 1964 earthquake

    USGS Publications Warehouse

    Suleimani, E.; Hansen, R.; Haeussler, P.J.

    2009-01-01

    We use a viscous slide model of Jiang and LeBlond (1994) coupled with nonlinear shallow water equations to study tsunami waves in Resurrection Bay, in south-central Alaska. The town of Seward, located at the head of Resurrection Bay, was hit hard by both tectonic and local landslide-generated tsunami waves during the MW 9.2 1964 earthquake with an epicenter located about 150 km northeast of Seward. Recent studies have estimated the total volume of underwater slide material that moved in Resurrection Bay during the earthquake to be about 211 million m3. Resurrection Bay is a glacial fjord with large tidal ranges and sediments accumulating on steep underwater slopes at a high rate. Also, it is located in a seismically active region above the Aleutian megathrust. All these factors make the town vulnerable to locally generated waves produced by underwater slope failures. Therefore it is crucial to assess the tsunami hazard related to local landslide-generated tsunamis in Resurrection Bay in order to conduct comprehensive tsunami inundation mapping at Seward. We use numerical modeling to recreate the landslides and tsunami waves of the 1964 earthquake to test the hypothesis that the local tsunami in Resurrection Bay has been produced by a number of different slope failures. We find that numerical results are in good agreement with the observational data, and the model could be employed to evaluate landslide tsunami hazard in Alaska fjords for the purposes of tsunami hazard mitigation. ?? Birkh??user Verlag, Basel 2009.

  2. The spatial distribution of organochlorine pesticides and halogenated flame retardants in the surface sediments of an Arctic fjord: the influence of ocean currents vs. glacial runoff.

    PubMed

    Ma, Yuxin; Xie, Zhiyong; Halsall, Crispin; Möller, Axel; Yang, Haizhen; Zhong, Guangcai; Cai, Minghong; Ebinghaus, Ralf

    2015-01-01

    Selected organochlorine pesticides (OCs) and halogenated flame retardants (HFRs) were analyzed in surficial fjord sediments collected down the length of Kongsfjorden, Svalbard in the Norwegian high Arctic. Hexachlorocyclohexane (α-HCHs) was found to be the most abundant OC in the sediment, followed by BDE-209>chlordane>α-endosulfan>Dechlorane Plus (anti-DP)>trifluralin concentration ranges were high over the relatively small study area of the fjord (e.g. ∑HCH: 7.2-100 pg g(-1) dry weight (dw)), with concentrations broadly similar to, or lower than, measurements conducted in other parts of the Arctic. Concentrations of legacy OCs, including both HCH isomers and chlordane showed a decreasing trend from the outer, seaward end of the fjord to the inner, glacier end of the fjord. Conversely, sediment concentrations of α- and β-endosulfan (0.1-12.5 pg g(-1) dw) increased from the outer fjord to the inner fjord. This contrasting pattern may be attributed to the influence of historical vs. contemporary sources of these chemicals to the fjord area, whereby the North Atlantic/West Spitzbergen oceanic current dominates the transport and input of the legacy OCs, whereas atmospheric deposition and meltwater runoff from the glaciers influence the inner fjord sediments for endosulfan. Interestingly, BDE-209 and Dechlorane Plus did not reveal any clear spatial trend. It is plausible that both glacial runoff and oceanic current end members are playing a role in introducing these chemicals to the fjord sediments. The relatively low fractional abundance of the syn-DP isomer (fsyn), however, indicates the long-range transport of this chemical to this Arctic site. PMID:25303654

  3. Genome sequence of "Candidatus Aquiluna" sp. strain IMCC13023, a marine member of the Actinobacteria isolated from an arctic fjord.

    PubMed

    Kang, Ilnam; Lee, Kiyoung; Yang, Seung-Jo; Choi, Ahyoung; Kang, Dongmin; Lee, Yoo Kyoung; Cho, Jang-Cheon

    2012-07-01

    We report the genome sequence of actinobacterial strain IMCC13023, isolated from arctic fjord seawater. Phylogenetic analysis of 16S rRNA gene showed that the strain is related to "Candidatus Aquiluna rubra." The genome information suggests that strain IMCC13023 is a photoheterotroph carrying actinorhodopsin, with the smallest genome ever reported for a free-living member of the Actinobacteria. PMID:22689238

  4. Mid-summer mesozooplankton biomass, its size distribution, and estimated production within a glacial Arctic fjord (Hornsund, Svalbard)

    NASA Astrophysics Data System (ADS)

    Trudnowska, E.; Basedow, S. L.; Blachowiak-Samolyk, K.

    2014-09-01

    The estimation of secondary production constitutes an integrating proxy of pelagic ecosystem status, its functions as well as its responses to environmental stressors. The combination of high-resolution automatic measurements with a Laser Optical Plankton Counter (LOPC) and size spectrum analyses was utilized to estimate the secondary production of a high Arctic fjord during a summer post bloom situation in 2012. The dataset comprised 28 vertical and extensive horizontal hauls of a LOPC-CTD-fluorometer platform plus four zooplankton net sampling stations for taxonomic composition designation. A clear gradient in temperature, salinity, chlorophyll a concentrations as well as mesozooplankton abundance, biomass and production was demonstrated along Hornsund fjord axis. The outer fjord part was under the influence of water advection and had the highest chlorophyll a concentrations, numerous opaque mesozooplankton individuals and flat slopes of size spectra, pointing to long food chains in which biomass is recycled several times. The opposite state was found in the glacial bays, where the glacier meltwater discharge led to low chlorophyll a concentrations but high abundance of small and amorphous particles. It resulted in steep size spectra slopes and high intercepts implying higher potential productivity there. The model of mesozooplankton production demonstrated that Hornsund fjord is a highly productive ecosystem, particularly its upper water layer and its central parts. However, we would like to emphasize that a careful approach is needed before going deeper into ecological interpretations based on size spectra analysis, especially in reservoirs, where non-zooplankton particles contribute to the size spectra.

  5. Bathymetry data reveal glaciers vulnerable to ice-ocean interaction in Uummannaq and Vaigat glacial fjords, west Greenland

    NASA Astrophysics Data System (ADS)

    Rignot, E.; Fenty, I.; Xu, Y.; Cai, C.; Velicogna, I.; Cofaigh, C. Ó.; Dowdeswell, J. A.; Weinrebe, W.; Catania, G.; Duncan, D.

    2016-03-01

    Marine-terminating glaciers play a critical role in controlling Greenland's ice sheet mass balance. Their frontal margins interact vigorously with the ocean, but our understanding of this interaction is limited, in part, by a lack of bathymetry data. Here we present a multibeam echo sounding survey of 14 glacial fjords in the Uummannaq and Vaigat fjords, west Greenland, which extends from the continental shelf to the glacier fronts. The data reveal valleys with shallow sills, overdeepenings (>1300 m) from glacial erosion, and seafloor depths 100-1000 m deeper than in existing charts. Where fjords are deep enough, we detect the pervasive presence of warm, salty Atlantic Water (AW) (>2.5°C) with high melt potential, but we also find numerous glaciers grounded on shallow (<200 m) sills, standing in cold (<1°C) waters in otherwise deep fjords, i.e., with reduced melt potential. Bathymetric observations extending to the glacier fronts are critical to understand the glacier evolution.

  6. Educating medical students for Alaska.

    PubMed

    Fortuine, R; Dimino, M J

    1998-01-01

    Because Alaska does not have its own medical school, it has become part of WAMI (Washington, Alaska, Montana, Idaho), an educational agreement with the University of Washington School of Medicine (UWSM). Each year, 10 Alaskans are accepted into the entering class of UWSM and spend their first year at the University of Alaska Anchorage (UAA). UWSM third- and fourth-year medical students can obtain some of their clinical experience in Alaska. To meet the needs of Alaska, students are chosen based on academic and personal records, as well as the likelihood of their returning to Alaska for practice. To this end, over the last seven years 30% of accepted students have come from rural communities and 10% are Alaska Natives. The curriculum for the first year includes several sessions dedicated to Alaska health problems, cross-cultural issues, and Alaska's unique rural health care delivery system. Students do two preceptorships--one with a private primary care physician and one with a physician at the Alaska Native Medical Center. Additionally, students have the option to spend a week at a rural site to learn about the community's health care system. An Alaska track is being developed whereby an Alaskan UWSM student can do most of the third year in state via clerkships in family medicine, obstetrics/gynecology, psychiatry, internal medicine, and pediatrics. All UWSM students at the end of their first year can elect to participate for one month in the R/UOP (Rural/Underserved Opportunities Program), which includes several Alaska sites. The overall goals of these approaches are to educate UWSM students, especially Alaskans, about the state's health needs and health care system and to encourage UWSM graduates to practice in the state.

  7. Seasonal variation in methane emissions from an interior Alaska thermokarst lake

    NASA Astrophysics Data System (ADS)

    Strohm, A. J.; Walter Anthony, K.; Thalasso, F.; Sepulveda-Jauregui, A.; Martinez Cruz, K. C.; Dove, K. L.

    2011-12-01

    Refining our knowledge of methane cycling in aquatic ecosystems and their emissions to the atmosphere is important for understanding their role in climate change. The contribution of northern high latitude lakes to terrestrial methane emissions has recently been recognized as significant, and is likely to contribute a positive feedback to increasing atmospheric temperatures. The data available for accurately defining seasonal and net annual methane emissions from northern high latitude lakes are presently limited by a seasonal imbalance in both gross and net production measurements, as well as a poor understanding of emissions pathways and geographic differences. To help fill in some of these data gaps, we conducted intensive year-round measurement of ebullition and diffusive methane flux from Goldstream Lake (informal name), a thermokarst lake in central Alaska. Additionally, we made less frequent measurements on 47 lakes in winter and summer along a latitudinal transect in Alaska from the Kenai Peninsula to Prudhoe Bay. We used several methods to measure methane flux over multiple seasons in order to better understand complexity in the fate and transport of methane. These include (i) static chamber measurements of seep ebullition, (ii) documentation of the fate of gas trapped in winter ice, (iii) dissolved gas measurements by both gas chromatography and Tunable Diode Laser Absorption Spectroscopy, and(iv) measurement of methane concentration in air above the lake surface by a LiCor 7700 Open Path Methane Analyzer. Of specific interest was seasonal variation in methane emissions and the fate of winter methane production, whose release to the atmosphere is restricted for seven months by increasingly thick ice cover.

  8. Deformation driven by subduction and microplate collision: Geodynamics of Cook Inlet basin, Alaska

    USGS Publications Warehouse

    Bruhn, R.L.; Haeussler, P.J.

    2006-01-01

    Late Neogene and younger deformation in Cook Inlet basin is caused by dextral transpression in the plate margin of south-central Alaska. Collision and subduction of the Yakutat microplate at the northeastern end of the Aleutian subduction zone is driving the accretionary complex of the Chugach and Kenai Mountains toward the Alaska Range on the opposite side of the basin. This deformation creates belts of fault-cored anticlines that are prolific traps of hydrocarbons and are also potential sources for damaging earthquakes. The faults dip steeply, extend into the Mesozoic basement beneath the Tertiary basin fill, and form conjugate flower structures at some localities. Comparing the geometry of the natural faults and folds with analog models created in a sandbox deformation apparatus suggests that some of the faults accommodate significant dextral as well as reverse-slip motion. We develop a tectonic model in which dextral shearing and horizontal shortening of the basin is driven by microplate collision with an additional component of thrust-type strain caused by plate subduction. This model predicts temporally fluctuating stress fields that are coupled to the recurrence intervals of large-magnitude subduction zone earthquakes. The maximum principal compressive stress is oriented east-southeast to east-northeast with nearly vertical least compressive stress when the basin's lithosphere is mostly decoupled from the underlying subduction megathrust. This stress tensor is compatible with principal stresses inferred from focal mechanisms of earthquakes that occur within the crust beneath Cook Inlet basin. Locking of the megathrust between great magnitude earthquakes may cause the maximum principal compressive stress to rotate toward the northwest. Moderate dipping faults that strike north to northeast may be optimally oriented for rupture in the ambient stress field, but steeply dipping faults within the cores of some anticlines are unfavorably oriented with respect to

  9. Shrubline but not treeline advance matches climate velocity in montane ecosystems of south-central Alaska.

    PubMed

    Dial, Roman J; Smeltz, T Scott; Sullivan, Patrick F; Rinas, Christina L; Timm, Katriina; Geck, Jason E; Tobin, S Carl; Golden, Trevor S; Berg, Edward C

    2016-05-01

    Tall shrubs and trees are advancing into many tundra and wetland ecosystems but at a rate that often falls short of that predicted due to climate change. For forest, tall shrub, and tundra ecosystems in two pristine mountain ranges of Alaska, we apply a Bayesian, error-propagated calculation of expected elevational rise (climate velocity), observed rise (biotic velocity), and their difference (biotic inertia). We show a sensitive dependence of climate velocity on lapse rate and derive biotic velocity as a rigid elevational shift. Ecosystem presence identified from recent and historic orthophotos ~50 years apart was regressed on elevation. Biotic velocity was estimated as the difference between critical point elevations of recent and historic logistic fits divided by time between imagery. For both mountain ranges, the 95% highest posterior density of climate velocity enclosed the posterior distributions of all biotic velocities. In the Kenai Mountains, mean tall shrub and climate velocities were both 2.8 m y(-1). In the better sampled Chugach Mountains, mean tundra retreat was 1.2 m y(-1) and climate velocity 1.3 m y(-1). In each mountain range, the posterior mode of tall woody vegetation velocity (the complement of tundra) matched climate velocity better than either forest or tall shrub alone, suggesting competitive compensation can be important. Forest velocity was consistently low at 0.1-1.1 m y(-1), indicating treeline is advancing slowly. We hypothesize that the high biotic inertia of forest ecosystems in south-central Alaska may be due to competition with tall shrubs and/or more complex climate controls on the elevational limits of trees than tall shrubs. Among tall shrubs, those that disperse farthest had lowest inertia. Finally, the rapid upward advance of woody vegetation may be contributing to regional declines in Dall's sheep (Ovis dalli), a poorly dispersing alpine specialist herbivore with substantial biotic inertia due to dispersal reluctance.

  10. Shrubline but not treeline advance matches climate velocity in montane ecosystems of south-central Alaska.

    PubMed

    Dial, Roman J; Smeltz, T Scott; Sullivan, Patrick F; Rinas, Christina L; Timm, Katriina; Geck, Jason E; Tobin, S Carl; Golden, Trevor S; Berg, Edward C

    2016-05-01

    Tall shrubs and trees are advancing into many tundra and wetland ecosystems but at a rate that often falls short of that predicted due to climate change. For forest, tall shrub, and tundra ecosystems in two pristine mountain ranges of Alaska, we apply a Bayesian, error-propagated calculation of expected elevational rise (climate velocity), observed rise (biotic velocity), and their difference (biotic inertia). We show a sensitive dependence of climate velocity on lapse rate and derive biotic velocity as a rigid elevational shift. Ecosystem presence identified from recent and historic orthophotos ~50 years apart was regressed on elevation. Biotic velocity was estimated as the difference between critical point elevations of recent and historic logistic fits divided by time between imagery. For both mountain ranges, the 95% highest posterior density of climate velocity enclosed the posterior distributions of all biotic velocities. In the Kenai Mountains, mean tall shrub and climate velocities were both 2.8 m y(-1). In the better sampled Chugach Mountains, mean tundra retreat was 1.2 m y(-1) and climate velocity 1.3 m y(-1). In each mountain range, the posterior mode of tall woody vegetation velocity (the complement of tundra) matched climate velocity better than either forest or tall shrub alone, suggesting competitive compensation can be important. Forest velocity was consistently low at 0.1-1.1 m y(-1), indicating treeline is advancing slowly. We hypothesize that the high biotic inertia of forest ecosystems in south-central Alaska may be due to competition with tall shrubs and/or more complex climate controls on the elevational limits of trees than tall shrubs. Among tall shrubs, those that disperse farthest had lowest inertia. Finally, the rapid upward advance of woody vegetation may be contributing to regional declines in Dall's sheep (Ovis dalli), a poorly dispersing alpine specialist herbivore with substantial biotic inertia due to dispersal reluctance. PMID

  11. Significant Alaska minerals

    SciTech Connect

    Robinson, M.S.; Bundtzen, T.K.

    1982-01-01

    Alaska ranks in the top four states in gold production. About 30.5 million troy oz have been produced from lode and placer deposits. Until 1930, Alaska was among the top 10 states in copper production; in 1981, Kennecott Copper Company had prospects of metal worth at least $7 billion. More than 85% of the 20 million oz of silver derived have been byproducts of copper mining. Nearly all lead production has been as a byproduct of gold milling. Molybdenum is a future Alaskan product; in 1987 production is scheduled to be about 12% of world demand. Uranium deposits discovered in the Southeast are small but of high grade and easily accessible; farther exploration depends on improvement of a depressed market. Little has been done with Alaskan iron and zinc, although large deposits of the latter were discovered. Alaskan jade has a market among craftspeople. A map of the mining districts is included. 2 figures, 1 table.

  12. Seabirds in Alaska

    USGS Publications Warehouse

    Hatch, Scott A.; Piatt, John F.

    1995-01-01

    Techniques for monitoring seabird populations vary according to habitat types and the breeding behavior of individual species (Hatch and Hatch 1978, 1989; Byrd et al. 1983). An affordable monitoring program can include but a few of the 1,300 seabird colonies identified in Alaska, and since the mid-1970's, monitoring effotrts have emphasized a small selection of surface-feeding and diving species, primarily kittiwakes (Rissa spp.) and murres (Uria spp.). Little or no information on trends is available for other seabirds (Hatch 1993a). The existing monitoring program occurs largely on sites within the Alaska Maritime National Wildlife Refuge, which was established primarily for the conservation of marine birds. Data are collected by refuge staff, other state and federal agencies, private organizations, university faculty, and students.

  13. Coal resources of Alaska

    SciTech Connect

    Sanders, R.B.

    1982-01-01

    In the late 1800s, whaling ships carried Alaskan coal, and it was used to thaw ground for placer gold mining. Unfortunate and costly political maneuvers in the early 1900s delayed coal removal, but the Alaska Railroad and then World War II provided incentives for opening mines. Today, 33 million acres (about 9% of the state) is classified as prospectively valuable for coal, much of it under federal title. Although the state's geology is poorly known, potential for discovery of new fields exists. The US Geological Survey estimates are outdated, although still officially used. The total Alaska onshore coal resource is estimated to be 216 to 4216 billion tons of which 141 billion tons are identified resources; an additional 1430 billion tons are believed to lie beneath Cook Inlet. Transportation over mountain ranges and wetlands is the biggest hurdle for removal. Known coal sources and types are described and mapped. 1 figure.

  14. Exploring the Diversity and Antimicrobial Potential of Marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile

    PubMed Central

    Undabarrena, Agustina; Beltrametti, Fabrizio; Claverías, Fernanda P.; González, Myriam; Moore, Edward R. B.; Seeger, Michael; Cámara, Beatriz

    2016-01-01

    Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although, Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae, and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera) was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus, and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium, and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%), PKS I (18%), and PKS II (73%). Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds. PMID:27486455

  15. Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords.

    PubMed

    Canales-Aguirre, Cristian B; Ferrada-Fuentes, Sandra; Galleguillos, Ricardo; Hernández, Cristián E

    2016-01-01

    Marine environmental variables can play an important role in promoting population genetic differentiation in marine organisms. Although fjord ecosystems have attracted much attention due to the great oscillation of environmental variables that produce heterogeneous habitats, species inhabiting this kind of ecosystem have received less attention. In this study, we used Sprattus fuegensis, a small pelagic species that populates the inner waters of the continental shelf, channels and fjords of Chilean Patagonia and Argentina, as a model species to test whether environmental variables of fjords relate to population genetic structure. A total of 282 individuals were analyzed from Chilean Patagonia with eight microsatellite loci. Bayesian and non-Bayesian analyses were conducted to describe the genetic variability of S. fuegensis and whether it shows spatial genetic structure. Results showed two well-differentiated genetic clusters along the Chilean Patagonia distribution (i.e. inside the embayment area called TicToc, and the rest of the fjords), but no spatial isolation by distance (IBD) pattern was found with a Mantel test analysis. Temperature and nitrate were correlated to the expected heterozygosities and explained the allelic frequency variation of data in the redundancy analyses. These results suggest that the singular genetic differences found in S. fuegensis from inside TicToc Bay (East of the Corcovado Gulf) are the result of larvae retention bya combination of oceanographic mesoscale processes (i.e. the west wind drift current reaches the continental shelf exactly in this zone), and the local geographical configuration (i.e. embayment area, islands, archipelagos). We propose that these features generated an isolated area in the Patagonian fjords that promoted genetic differentiation by drift and a singular biodiversity, adding support to the existence of the largest marine protected area (MPA) of continental Chile, which is the Tic-Toc MPA. PMID:27505009

  16. Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords

    PubMed Central

    Ferrada-Fuentes, Sandra; Galleguillos, Ricardo; Hernández, Cristián E.

    2016-01-01

    Marine environmental variables can play an important role in promoting population genetic differentiation in marine organisms. Although fjord ecosystems have attracted much attention due to the great oscillation of environmental variables that produce heterogeneous habitats, species inhabiting this kind of ecosystem have received less attention. In this study, we used Sprattus fuegensis, a small pelagic species that populates the inner waters of the continental shelf, channels and fjords of Chilean Patagonia and Argentina, as a model species to test whether environmental variables of fjords relate to population genetic structure. A total of 282 individuals were analyzed from Chilean Patagonia with eight microsatellite loci. Bayesian and non-Bayesian analyses were conducted to describe the genetic variability of S. fuegensis and whether it shows spatial genetic structure. Results showed two well-differentiated genetic clusters along the Chilean Patagonia distribution (i.e. inside the embayment area called TicToc, and the rest of the fjords), but no spatial isolation by distance (IBD) pattern was found with a Mantel test analysis. Temperature and nitrate were correlated to the expected heterozygosities and explained the allelic frequency variation of data in the redundancy analyses. These results suggest that the singular genetic differences found in S. fuegensis from inside TicToc Bay (East of the Corcovado Gulf) are the result of larvae retention bya combination of oceanographic mesoscale processes (i.e. the west wind drift current reaches the continental shelf exactly in this zone), and the local geographical configuration (i.e. embayment area, islands, archipelagos). We propose that these features generated an isolated area in the Patagonian fjords that promoted genetic differentiation by drift and a singular biodiversity, adding support to the existence of the largest marine protected area (MPA) of continental Chile, which is the Tic-Toc MPA. PMID:27505009

  17. Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords.

    PubMed

    Canales-Aguirre, Cristian B; Ferrada-Fuentes, Sandra; Galleguillos, Ricardo; Hernández, Cristián E

    2016-01-01

    Marine environmental variables can play an important role in promoting population genetic differentiation in marine organisms. Although fjord ecosystems have attracted much attention due to the great oscillation of environmental variables that produce heterogeneous habitats, species inhabiting this kind of ecosystem have received less attention. In this study, we used Sprattus fuegensis, a small pelagic species that populates the inner waters of the continental shelf, channels and fjords of Chilean Patagonia and Argentina, as a model species to test whether environmental variables of fjords relate to population genetic structure. A total of 282 individuals were analyzed from Chilean Patagonia with eight microsatellite loci. Bayesian and non-Bayesian analyses were conducted to describe the genetic variability of S. fuegensis and whether it shows spatial genetic structure. Results showed two well-differentiated genetic clusters along the Chilean Patagonia distribution (i.e. inside the embayment area called TicToc, and the rest of the fjords), but no spatial isolation by distance (IBD) pattern was found with a Mantel test analysis. Temperature and nitrate were correlated to the expected heterozygosities and explained the allelic frequency variation of data in the redundancy analyses. These results suggest that the singular genetic differences found in S. fuegensis from inside TicToc Bay (East of the Corcovado Gulf) are the result of larvae retention bya combination of oceanographic mesoscale processes (i.e. the west wind drift current reaches the continental shelf exactly in this zone), and the local geographical configuration (i.e. embayment area, islands, archipelagos). We propose that these features generated an isolated area in the Patagonian fjords that promoted genetic differentiation by drift and a singular biodiversity, adding support to the existence of the largest marine protected area (MPA) of continental Chile, which is the Tic-Toc MPA.

  18. Exploring the Diversity and Antimicrobial Potential of Marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile.

    PubMed

    Undabarrena, Agustina; Beltrametti, Fabrizio; Claverías, Fernanda P; González, Myriam; Moore, Edward R B; Seeger, Michael; Cámara, Beatriz

    2016-01-01

    Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although, Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae, and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera) was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus, and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium, and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%), PKS I (18%), and PKS II (73%). Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds.

  19. Exploring the Diversity and Antimicrobial Potential of Marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile.

    PubMed

    Undabarrena, Agustina; Beltrametti, Fabrizio; Claverías, Fernanda P; González, Myriam; Moore, Edward R B; Seeger, Michael; Cámara, Beatriz

    2016-01-01

    Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although, Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae, and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera) was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus, and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium, and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%), PKS I (18%), and PKS II (73%). Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds. PMID:27486455

  20. Geologic map of Alaska

    USGS Publications Warehouse

    Wilson, Frederic H.; Hults, Chad P.; Mull, Charles G.; Karl, Susan M.

    2015-12-31

    This Alaska compilation is unique in that it is integrated with a rich database of information provided in the spatial datasets and standalone attribute databases. Within the spatial files every line and polygon is attributed to its original source; the references to these sources are contained in related tables, as well as in stand-alone tables. Additional attributes include typical lithology, geologic setting, and age range for the map units. Also included are tables of radiometric ages.

  1. Aniakchak Crater, Alaska Peninsula

    USGS Publications Warehouse

    Smith, Walter R.

    1925-01-01

    The discovery of a gigantic crater northwest of Aniakchak Bay (see fig. 11) closes what had been thought to be a wide gap in the extensive series of volcanoes occurring at irregular intervals for nearly 600 miles along the axial line of the Alaska Peninsula and the Aleutian Islands. In this belt there are more active and recently active volcanoes than in all the rest of North America. Exclusive of those on the west side of Cook Inlet, which, however, belong to the same group, this belt contains at least 42 active or well-preserved volcanoes and about half as many mountains suspected or reported to be volcanoes. The locations of some of these mountains and the hot springs on the Alaska Peninsula and the Aleutian Islands are shown on a map prepared by G. A. Waring. Attention has been called to these volcanoes for nearly two centuries, but a record of their activity since the discovery of Alaska is far from being complete, and an adequate description of them as a group has never been written. Owing to their recent activity or unusual scenic beauty, some of the best known of the group are Mounts Katmai, Bogoslof, and Shishaldin, but there are many other beautiful and interesting cones and craters.

  2. Analyses of past and present rock slope instabilities in a fjord valley: Implications for hazard estimations

    NASA Astrophysics Data System (ADS)

    Böhme, M.; Oppikofer, T.; Longva, O.; Jaboyedoff, M.; Hermanns, R. L.; Derron, M.-H.

    2015-11-01

    For quantitative hazard assessment it is necessary to define the magnitude-frequency distribution and a temporal model of the landslide frequency. This is often complicated for large rock slope failures due to the lack of significant numbers of large rock slope failures in inventories of a given homogeneous region or sparse information about the timing. An inventory of 108 rock slope failure deposits within the fjords of the Storfjord region including a relative rockslide chronostratigraphy was available for this study. The temporal distribution of rock slope failures is characterized by a rapid response with a high frequency of failures directly after deglaciation followed by a lower constant frequency since 9,000 years BP for the entire Storfjord region. The largest recorded volumes failed directly after deglaciation. Volumes larger than 5 × 106 m3 have not been recorded within the last 9,000 years. In addition, 17 rockslide scars and on the other hand 17 potential rock slope instabilities have been mapped at the northeastern flank of Tafjord, which is a branch of the Storfjord. Volume-frequency relations have been developed for the three inventories from Tafjord, comprising (i) fjord deposits, (ii) rockslide scars and (iii) potential instabilities. They result in very similar distributions over the entire volume range. All three inventories are underlying the same processes that lead to destabilisation and finally failure. Additionally, the compilation of the three inventories is independent and based on different methodologies. The similarity of the volume-frequency distributions is thus verifying the different inventories. Hence the obtained volume-frequency relation can be used to assess the rockslide hazard for the study area. Present day annual expectable frequencies for different volume classes have been assessed based on the obtained volume-frequency relation of the fjord deposits. For example, the average annual frequency for rock slope failures of V

  3. A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem.

    PubMed

    Harwell, Mark A; Gentile, John H; Cummins, Kenneth W; Highsmith, Raymond C; Hilborn, Ray; McRoy, C Peter; Parrish, Julia; Weingartner, Thomas

    2010-07-01

    Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems. PMID:20862192

  4. A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem.

    PubMed

    Harwell, Mark A; Gentile, John H; Cummins, Kenneth W; Highsmith, Raymond C; Hilborn, Ray; McRoy, C Peter; Parrish, Julia; Weingartner, Thomas

    2010-07-01

    Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems.

  5. A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem

    PubMed Central

    Harwell, Mark A.; Gentile, John H.; Cummins, Kenneth W.; Highsmith, Raymond C.; Hilborn, Ray; McRoy, C. Peter; Parrish, Julia; Weingartner, Thomas

    2010-01-01

    Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems. PMID:20862192

  6. Rural Alaska Mentoring Project (RAMP)

    ERIC Educational Resources Information Center

    Cash, Terry

    2011-01-01

    For over two years the National Dropout Prevention Center (NDPC) at Clemson University has been supporting the Lower Kuskokwim School District (LKSD) in NW Alaska with their efforts to reduce high school dropout in 23 remote Yup'ik Eskimo villages. The Rural Alaska Mentoring Project (RAMP) provides school-based E-mentoring services to 164…

  7. Alaska Native Land Claims. [Textbook].

    ERIC Educational Resources Information Center

    Arnold, Robert D.; And Others

    Written for students at the secondary level, this textbook on Alaska Native land claims includes nine chapters, eight appendices, photographs, maps, graphs, bibliography, and an index. Chapters are titled as follows: (1) Earliest Times (Alaska's first settlers, eighteenth century territories, and other claimants); (2) American Indians and Their…

  8. Numerical modeling experiments of coastal upwelling at the field of Arctic fjords.

    NASA Astrophysics Data System (ADS)

    Kosecki, Szymon; Dzierzbicka-Głowacka, Lidia

    2016-04-01

    Coastal upwelling is a well described, known phenomenon in theory. Nowadays there is more and more both environmental and modeling studies about it. Upwelling especially in the Arctic fjords is a process that strongly affects hydrodynamics and even more ecosystems. It is so important, that it brings detailed question about effects and needed wind driven forcing parameters. My modeling experiment studies were strongly different than the studies that are typically carried out using numerical models. Instead of searching for this phenomenon in modeled analysis or environmental data, I did several case scenarios simulations. For those I used statistically selected wind data measured in-stiu. The hi-resolution coastal mapping, the flexible mesh discretization method and the sigma-layered three dimensional model MIKE 3 by DHI allowed me to explore this phenomenon with very good accuracy. This studies have been done in Institute of Oceanology PAS in Sopot, as a part of Centre for Polar Studies.

  9. New constraining datasets for Eurasian ice sheet modelling: chronology, fjords and bedrock

    NASA Astrophysics Data System (ADS)

    Gyllencreutz, R.; Tarasov, L.; Mangerud, J.; Svendsen, J. I.; Lohne, Ø. S.

    2009-04-01

    The increasing resolution of ice sheet models demands more detailed data for constraining and for comparison of results. Important data for this include ice sheet chronology, bed conditions and topography. We address this by compiling published data into three new constraining data sets. The Eurasian ice sheet chronology is reconstructed in our database-GIS solution (called DATED; Gyllencreutz et al., 2007). In DATED, we are building a database with all available dates, and a GIS with all geomorphologic features, that are relevant for the ice configuration through the Last Glacial Maximum and the following deglaciation, based on results from the literature. Reconstructions of the ice sheet configuration are presented as thousand-year time slices of the advance and decay of the Eurasian ice sheet between 25 and 10 thousand calendar years ago, based on chronologic, geomorphologic and stratigraphic data from the literature. To facilitate handling of error estimates in ice sheet modeling using our reconstructions, we made three reconstructions for every time slice: a maximum, a minimum and a "probable" ice sheet configuration, based on the limitations of the data at hand. The estimated uncertainty for the reconstructions was calculated in the GIS, and amounts to about 1 million km2 (about 1/5 of the maximum area) for most of the record before the Younger Dryas, indicating significant gaps in the knowledge of the Eurasian ice sheet configuration. In order to facilitate modeling of fast ice flow and ice streams, we compiled information about exposed bedrock from digital Quaternary maps in scale 1:1 million by the geological surveys in Norway, Sweden, Finland, UK and Ireland, together with published drift thickness estimates. The bed conditions data set was generalized to a grid resolution of 0.25 x 0.25 degrees. The Norwegian fjords are important for topographic steering; especially for fast glacier flow and draw-down from more central parts of the ice sheet. However

  10. The transport and fate of particulate hydrocarbons in an urban fjord-like estuary

    NASA Astrophysics Data System (ADS)

    Murphy, Paulette P.; Bates, Timothy S.; Curl, Herbert C.; Feely, Richard A.; Scott Burger, R.

    1988-11-01

    Hydrocarbon concentrations were measured on suspended particulates and on surficial marine sediments in the urban fjord-like estuary of Puget Sound, Washington. These data were combined with sediment deposition rates, suspended particulate concentrations and circulation data to assess hydrocarbon distributions and fates. Evaluation of major sinks for petroleum hydrocarbons (UCM) and polycyclic aromatic hydrocarbons (PAH) in an urban estuary indicates that > 90% of the hydrocarbons which are associated with suspended particulates in the main basin of Puget Sound are deposited in the estuarine sediments. Approximately 63% of the PAH and 100% of the UCM associated with particles in the main basin settle directly to the sediments. The remainder is carried to the main basin sediments via horizontal transport from other areas. Trends in PAH ratios are used to identify major sources of PAH. Estimated sources of PAH are balanced by the estimated sinks.

  11. A model of the fate of polycyclic aromatic hydrocarbons in the Saguenay Fjord, Canada

    SciTech Connect

    Lun, R.; Lee, K.; Marco, L. de; Nalewajko, C.; Mackay, D. |

    1998-02-01

    A comprehensive mass balance model is described that simulates the fate of polycyclic aromatic hydrocarbons (PAHs) in the Saguenay Fjord in eastern Quebec, Canada. The receiving environment is segmented into five compartments that are connected by upstream and downstream flows. Each segment consists of a layer of surficial sediment and a water column exposed to the atmosphere. The steady state model provides a method by which defined loadings of PAHs from the atmosphere and industrial sources are combined with other input parameters such as advective flow and atmospheric deposition rates to deduce quantities, concentrations, and transport and transformation rates. Results are presented for naphthalene, phenanthrene, and benzo[a]pyrene. The overall environmental pathways and simulation results are discussed. The simulated concentrations of benzo[a]pyrene in the sediment ranged from 100 to 315 ng/g, which are in good agreement with reported measurements.

  12. Distribution and spawning dynamics of capelin (Mallotus villosus) in Glacier Bay, Alaska: A cold water refugium

    USGS Publications Warehouse

    Arimitsu, M.L.; Piatt, J.F.; Litzow, M.A.; Abookire, A.A.; Romano, Marc D.; Robards, M.D.

    2008-01-01

    Pacific capelin (Mallotus villosus) populations declined dramatically in the Northeastern Pacific following ocean warming after the regime shift of 1977, but little is known about the cause of the decline or the functional relationships between capelin and their environment. We assessed the distribution and abundance of spawning, non-spawning adult and larval capelin in Glacier Bay, an estuarine fjord system in southeastern Alaska. We used principal components analysis to analyze midwater trawl and beach seine data collected between 1999 and 2004 with respect to oceanographic data and other measures of physical habitat including proximity to tidewater glaciers and potential spawning habitat. Both spawning and non-spawning adult Pacific capelin were more likely to occur in areas closest to tidewater glaciers, and those areas were distinguished by lower temperature, higher turbidity, higher dissolved oxygen and lower chlorophyll a levels when compared with other areas of the bay. The distribution of larval Pacific capelin was not sensitive to glacial influence. Pre-spawning females collected farther from tidewater glaciers were at a lower maturity state than those sampled closer to tidewater glaciers, and the geographic variation in the onset of spawning is likely the result of differences in the marine habitat among sub-areas of Glacier Bay. Proximity to cold water in Glacier Bay may have provided a refuge for capelin during the recent warm years in the Gulf of Alaska.

  13. Exchange between the Prince William Sound and the Gulf of Alaska: Data over an annual cycle

    NASA Astrophysics Data System (ADS)

    Belanger, C.; Okkonen, S.

    2006-12-01

    Prince William Sound (PWS) is a small sub-arctic semi-enclosed sea located along the southern coast of Alaska. It is surrounded by mountains, glaciers, coastal rivers, and numerous bays and fjords, and it is connected to the northern Gulf of Alaska (GOA) via two major passages, Hinchinbrook Entrance (HE) and Montague Strait (MS). Previous studies identified the exchange between the northern GOA and PWS as one of the main physical processes influencing the biology of phytoplankton, zooplankton, and juvenile fish within the sound (Vaughn et al., 2001). Because the magnitude and variability of this exchange were not precisely known, nor was the relative importance of several forcings that could modulate this exchange, an observational program aiming to provide an improved description of the flow through these straits was initiated in June 2005. This program takes cross-strait variability into account, addressing a weakness of the previous observations. An array of moorings instrumented with upward- and downward-looking Acoustic Doppler Current Profilers (ADCPs) at mid-water column depth was deployed in HE and MS and in one of the minor passages (Prince of Wales Passage) in the southwest part of the sound. The moorings were also equipped with conductivity and temperature probes (CTs). This observational program is intended to last for five years. Data from the first annual cycle are presented.

  14. Detection of genotoxic substances in bivalve molluscs from the Saguenay Fjord (Canada), using the SOS chromotest.

    PubMed

    White, P A; Blaise, C; Rasmussen, J B

    1997-08-14

    Few studies have employed bioassays to investigate the accumulation of genotoxins in aquatic biota that inhabit areas contaminated with industrial and municipal wastes. This study employed the SOS Chromotest, a short-term bacterial genotoxicity assay, to investigate the presence of genotoxins in bivalve molluscs from the Saguenay Fjord (Canada). Genotoxicity analyses were performed on dichloromethane extracts of Mya arenaria and Mytilus edulis collected downstream from several aluminum refineries and forestry products industries known to produce and release genotoxic substances. The results confirmed that bivalve molluscs inhabiting downstream regions are contaminated with both direct-acting and pro-genotoxic substances. In several cases, SOS response induction factors exceeded 3.0. The results failed to reveal a clear downstream trend of decreasing genotoxicity with increasing distance from the presumed industrial sources(s). A significant relationship (r2 = 0.61, p < 0.007) between a demographic variable (population near shoreline) and lipid-corrected genotoxic potency suggest that the accumulated direct-acting genotoxins may be of municipal origin. Significant relationships between tissue extract genotoxicity (r2 = 0.75, p < 0.003) and tissue PAH contamination (r2 = 0.77, p < 0.0001) and drainage basin area suggests that the bivalves are accumulating airborne contaminants deposited on the surface of the relevant drainage basins. In spite of contamination with genotoxic PAHs, the addition of rat liver microsomal enzymes reduced the genotoxic potency of all samples investigated (31-94% decrease). The results also revealed a significant relationship between tissue extract genotoxicity and PAH concentration (r2 = 0.72, p < 0.0005). Further analyses confirmed that a variable portion (7-97%) of the S9-activated tissue extract genotoxicity can be attributed to the detected PAHs. Although the sources, identity and effects of genotoxins accumulated by bivalves of the

  15. A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes.

    PubMed

    Young, Duncan A; Wright, Andrew P; Roberts, Jason L; Warner, Roland C; Young, Neal W; Greenbaum, Jamin S; Schroeder, Dustin M; Holt, John W; Sugden, David E; Blankenship, Donald D; van Ommen, Tas D; Siegert, Martin J

    2011-06-01

    The first Cenozoic ice sheets initiated in Antarctica from the Gamburtsev Subglacial Mountains and other highlands as a result of rapid global cooling ∼34 million years ago. In the subsequent 20 million years, at a time of declining atmospheric carbon dioxide concentrations and an evolving Antarctic circumpolar current, sedimentary sequence interpretation and numerical modelling suggest that cyclical periods of ice-sheet expansion to the continental margin, followed by retreat to the subglacial highlands, occurred up to thirty times. These fluctuations were paced by orbital changes and were a major influence on global sea levels. Ice-sheet models show that the nature of such oscillations is critically dependent on the pattern and extent of Antarctic topographic lowlands. Here we show that the basal topography of the Aurora Subglacial Basin of East Antarctica, at present overlain by 2-4.5 km of ice, is characterized by a series of well-defined topographic channels within a mountain block landscape. The identification of this fjord landscape, based on new data from ice-penetrating radar, provides an improved understanding of the topography of the Aurora Subglacial Basin and its surroundings, and reveals a complex surface sculpted by a succession of ice-sheet configurations substantially different from today's. At different stages during its fluctuations, the edge of the East Antarctic Ice Sheet lay pinned along the margins of the Aurora Subglacial Basin, the upland boundaries of which are currently above sea level and the deepest parts of which are more than 1 km below sea level. Although the timing of the channel incision remains uncertain, our results suggest that the fjord landscape was carved by at least two iceflow regimes of different scales and directions, each of which would have over-deepened existing topographic depressions, reversing valley floor slopes. PMID:21637255

  16. Uranium biogeochemistry across the redox transition zone of a permanently stratified fjord: Framvaren, Norway

    USGS Publications Warehouse

    Swarzenski, P.W.; McKee, B.A.; Skei, J.M.; Todd, J.F.

    1999-01-01

    During August 1995, the vertical concentration profile of dissolved and particulate uranium exhibited strong non-conservative characteristics in the upper 30 m of Framvaren Fjord. There was a pronounced peak in both particulate (> 0.2 ??m; 1.09 nM) and dissolved (< 0.2 ??m; 17.06 nM) uranium in the finely stratified waters at the O2/H2S interface which is positioned well within the euphotic zone at about 20-21 m. Such concentration maxima at the redox boundary are also observed for dissolved organic carbon (DEC), Sr and Ba. Dissolved U levels seen in the water column from 18 m down to 30 m exceeded the high salinity (salinity = 35) U concentrations (13.63 ?? 0.84 nM; Chen, J.H., Edwards, R.L., Wasserburg, G.L., 1986. 238U, 234U and 232Th in seawater. Earth Planet Sci. Lett. 80, 241-251.) observed uniformly in the open ocean. A prolific population of S microbes (e.g., Chromatium, Chlorobium sp.) flourishes at the O2/H2S interface. The source of elevated U at the redox boundary must be due to microbial uptake and subsequent release processes rather than dilution from oceanic uranium. Uranium oxidation state determinations in waters from 1, 22 and 30 m depth reveal that reduced U(IV) is not present in significant abundance, and that the chemical and/or biological reduction of hexavalent uranium is largely inhibited. Our results suggest that U and other trace constituents such as DOC, Sr, Ba, Fe(II), Mn(II) are greatly modified by direct and indirect microbial transformation reactions which are most concentrated across the redox transition zone in Framvaren Fjord.

  17. Shelf/fjord exchange driven by coastal-trapped waves in the Arctic

    NASA Astrophysics Data System (ADS)

    Inall, Mark E.; Nilsen, Frank; Cottier, Finlo R.; Daae, Ragnhild

    2015-12-01

    In this article, we show that the class of low frequency (subinertial) waves known as coastal-trapped waves (CTWs) are a significant agent of water volume exchange in a west Svalbard fjord, and by extension more widely along the west Svalbard and east Greenland margins where similar conditions prevail. We show that CTWs generated by weather systems passing across the sloping topography of the shelf break propagate into the fjord, steered by the topography of an across-shelf trough. The CTWs have characteristic periods of ˜2 days, set by the passage time of weather systems. Phase speeds and wavelengths vary seasonally by a factor of two, according to stratification: winter (summer) values are Cp = 0.25 ms-1 (0.5 ms-1) and λ = 40 km (84 km). CTW-induced flow velocities in excess of 0.2 ms-1 at 100 m water depth are recorded. Observationally scaled CTW model results allow their explicit role in volume exchange to be quantified. Of the estimated exchange terms, estuarine exchange is weakest (Qest=0.62×103 m3s-1), followed by barotropic tidal pumping (Qbt=2.5×103 m3s-1), with intermediary exchange dominating (Qi=2.4×104 m3s-1). Oscillatory flows display greatest activity in the 1-5 day period band, and CTW activity is identified as the likely source of variability in the 40-60 h period band. Within that band, intermediary exchange driven by CTWs is estimated as QiCTW_ave=0.82×104 m3s-1; an exchange rate exceeding both barotropic and estuarine exchange estimates.

  18. Inorganic carbon in a high latitude estuary-fjord system in Canada's eastern Arctic

    NASA Astrophysics Data System (ADS)

    Turk, D.; Bedard, J. M.; Burt, W. J.; Vagle, S.; Thomas, H.; Azetsu-Scott, K.; McGillis, W. R.; Iverson, S. J.; Wallace, D. W. R.

    2016-09-01

    Rapidly changing conditions in the Arctic can have a significant impact on biogeochemical cycles and can be particularly important in high latitude estuary-fjord systems with abundant and diverse freshwater sources. This study provides a first look into the inorganic carbon system and its relation to freshwater sources in Cumberland Sound in the east coast of Baffin Island, Nunavut, Canada. These data contribute to the very limited set of inorganic carbon measurements in high latitude estuary-fjord systems. During the ice-free conditions in August 2011, the meteoric freshwater fractions (MW) in the upper 40 m ranged from 11 to 21% and no sea ice melt (SIM) was present in the Sound. Surface waters were undersaturated with pCO2 (260 and 300 μatm), and DIC and TA ranged between 1779 and 1966 μmol DIC kg-1, and 1922 and 2140 μmol TA kg-1, respectively. Aragonite saturation (ΩAr) state ranged from 1.9 in the surface to 1.4 in the subsurface waters. Data show decreasing TA and ΩAr with increasing MW fraction and suggest that Cumberland Sound waters would become aragonite undersaturated (ΩAr < 1) at MW = 0.37 (95% CI: 0.29 to 0.56). Estimated local δ18O (-19.2‰) and TA (174 μmol TA kg-1) end-members indicate MW was most likely a mixture of river water and glacial melt. In August 2012, MW fractions at the surface were between 8 and 11.5%, and SIM between 7 and 23%. Significant interannual variability of summertime SIM could potentially result in ΩAr undersaturation.

  19. GeoFORCE Alaska, A Successful Summer Exploring Alaska's Geology

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2012-12-01

    Thirty years old this summer, RAHI, the Rural Alaska Honors Institute is a statewide, six-week, summer college-preparatory bridge program at the University of Alaska Fairbanks for Alaska Native and rural high school juniors and seniors. This summer, in collaboration with the University of Texas Austin, the Rural Alaska Honors Institute launched a new program, GeoFORCE Alaska. This outreach initiative is designed to increase the number and diversity of students pursuing STEM degree programs and entering the future high-tech workforce. It uses Earth science to entice kids to get excited about dinosaurs, volcanoes and earthquakes, and includes physics, chemistry, math, biology and other sciences. Students were recruited from the Alaska's Arctic North Slope schools, in 8th grade to begin the annual program of approximately 8 days, the summer before their 9th grade year and then remain in the program for all four years of high school. They must maintain a B or better grade average and participate in all GeoFORCE events. The culmination is an exciting field event each summer. Over the four-year period, events will include trips to Fairbanks and Anchorage, Arizona, Oregon and the Appalachians. All trips focus on Earth science and include a 100+ page guidebook, with tests every night culminating with a final exam. GeoFORCE Alaska was begun by the University of Alaska Fairbanks in partnership with the University of Texas at Austin, which has had tremendous success with GeoFORCE Texas. GeoFORCE Alaska is managed by UAF's long-standing Rural Alaska Honors Institute, that has been successfully providing intense STEM educational opportunities for Alaskan high school students for over 30 years. The program will add a new cohort of 9th graders each year for the next four years. By the summer of 2015, GeoFORCE Alaska is targeting a capacity of 160 students in grades 9th through 12th. Join us to find out more about this exciting new initiative, which is enticing young Alaska Native

  20. Geochemistry of surface sediments from the fjords of Northern Chilean Patagonia (44-47°S): Spatial variability and implications for paleoclimate reconstructions

    NASA Astrophysics Data System (ADS)

    Bertrand, Sébastien; Hughen, Konrad A.; Sepúlveda, Julio; Pantoja, Silvio

    2012-01-01

    The Patagonian fjords have a clear potential to provide high-resolution sedimentary and geochemical records of past climate and environmental change in the Southern Andes. To improve our ability to interpret these proxy records, we investigated the processes that control fjord sediment inorganic geochemistry through a geochemical, mineralogical and sedimentological analysis of surface sediment samples from the fjords of Northern Chilean Patagonia. A simple Terrestrial Index based on measurements of salinity and Fraction of Terrestrial Carbon was used to estimate the terrestrial input/river discharge at each site. Our results demonstrate that, under the cold climate conditions of Patagonia, chemical weathering is weak and the inorganic geochemical composition of the fjord sediments is primarily controlled by hydrodynamic mineralogical sorting, i.e., the intensity of river discharge. Our results suggest that the distribution of Fe, Ti and Zr in surface sediments is controlled by their association with heavy and/or coarse minerals, whereas Al is independent of hydrodynamic processes. The elemental ratios Fe/Al, Ti/Al and Zr/Al are therefore well suited for estimating changes in the energy of terrestrial sediment supply into the fjords through time. Zr/Al is particularly sensitive in proximal environments, while Fe/Al is most useful in the outer fjords and on the continental margin. In the most proximal environments, however, Fe/Al is inversely related to hydrodynamic conditions. Caution should therefore be exercised when interpreting Fe/Al ratios in terms of past river discharge. The application of these proxies to long sediment cores from Quitralco fjord and Golfo Elefantes validates our interpretations. Our results also emphasize the need to measure Al-based elemental ratios at high precision, which can be achieved using simultaneous acquisition ICP-AES technology. This study therefore constitutes a strong basis for the interpretation of sedimentary records from the

  1. 2013 Alaska Performance Scholarship Outcomes Report

    ERIC Educational Resources Information Center

    Rae, Brian

    2013-01-01

    In accordance with Alaska statute the departments of Education & Early Development (EED) and Labor and Workforce Development (DOLWD), the University of Alaska (UA), and the Alaska Commission on Postsecondary Education (ACPE) present this second annual report on the Alaska Performance Scholarship (APS). Among the highlights: (1) In the public…

  2. Temporal and spatial distribution of floating objects in coastal waters of central-southern Chile and Patagonian fjords

    NASA Astrophysics Data System (ADS)

    Hinojosa, Iván A.; Rivadeneira, Marcelo M.; Thiel, Martin

    2011-03-01

    Floating objects are suggested to be the principal vector for the transport and dispersal of marine invertebrates with direct development as well as catalysts for carbon and nutrient recycling in accumulation areas. The first step in identifying the ecological relevance of floating objects in a specific area is to identify their spatio-temporal distribution. We evaluated the composition, abundance, distribution, and temporal variability of floating objects along the continental coast of central-southern Chile (33-42°S) and the Patagonian fjords (42-50°S) using ship surveys conducted in austral winter (July/August) and spring (November) of the years 2002-2005 and 2008. Potential sources of floating items were identified with the aid of publicly available databases and scientific reports. We found three main types of floating objects, namely floating marine debris (mainly plastic objects and Styrofoam), wood (trunks and branches), and floating kelps ( Macrocystis pyrifera and Durvillaea antarctica). Floating marine debris were abundant along most of the examined transects, with markedly lower abundances toward the southern fjord areas. Floating marine debris abundances generally corresponded to the distribution of human activities, and were highest in the Interior Sea of Chiloé, where aquaculture activities are intense. Floating wood appeared sporadically in the study area, often close to the main rivers. In accordance with seasonal river run-off, wood was more abundant along the continental coast in winter (rainy season) and in the Patagonian fjords during the spring surveys (snow melt). Densities of the two floating kelp species were similar along the continental coast, without a clear seasonal pattern. M. pyrifera densities increased towards the south, peaking in the Patagonian fjords, where it was dominant over D. antarctica. Densities of M. pyrifera in the Patagonian fjords were highest in spring. Correlation analyses between the abundances of floating

  3. Geologic framework of the Alaska Peninsula, southwest Alaska, and the Alaska Peninsula terrane

    USGS Publications Warehouse

    Wilson, Frederic H.; Detterman, Robert L.; DuBois, Gregory D.

    2015-01-01

    The boundaries separating the Alaska Peninsula terrane from other terranes are commonly indistinct or poorly defined. A few boundaries have been defined at major faults, although the extensions of these faults are speculative through some areas. The west side of the Alaska Peninsula terrane is overlapped by Tertiary s

  4. Geologic framework of the Alaska Peninsula, southwest Alaska, and the Alaska Peninsula terrane

    USGS Publications Warehouse

    Wilson, Frederic H.; Detterman, Robert L.; DuBois, Gregory D.

    2015-01-01

    The boundaries separating the Alaska Peninsula terrane from other terranes are commonly indistinct or poorly defined. A few boundaries have been defined at major faults, although the extensions of these faults are speculative through some areas. The west side of the Alaska Peninsula terrane is overlapped by Tertiary sedimentary and volcanic rocks and Quaternary deposits.

  5. 78 FR 53137 - Flint Hills Resources Alaska, LLC, BP Pipelines (Alaska) Inc., ConocoPhillips Transportation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ...Phillips Transportation Alaska, Inc., ExxonMobil Pipeline Company; Notice of Complaint Take notice that on... formal complaint against BP Pipelines (Alaska) Inc., ConocoPhillips Transportation Alaska, Inc.,...

  6. Distribution of bacterial populations in a stratified fjord (Mariager Fjord, Denmark) quantified by in situ hybridization and related to chemical gradients in the water column.

    PubMed

    Ramsing, N B; Fossing, H; Ferdelman, T G; Andersen, F; Thamdrup, B

    1996-04-01

    The vertical distribution of major and intermediate electron acceptors and donors was measured in a shallow stratified fjord. Peaks of zero valence sulfur, Mn(IV), and Fe(III) were observed in the chemocline separating oxic surface waters from sulfidic and anoxic bottom waters. The vertical fluxes of electron acceptors and donors (principally O2 and H2S) balanced within 5%; however, the zones of oxygen reduction and sulfide oxidation were clearly separated. The pathway of electron transfer between O2 and H2S was not apparent from the distribution of sulfur, nitrogen, or metal compounds investigated. The chemical zonation was related to bacterial populations as detected by ethidium bromide (EtBr) staining and by in situ hybridization with fluorescent oligonucleotide probes of increasing specificity. About half of all EtBr-stained cells were detectable with a general oligonucleotide probe for all eubacteria when digital image analysis algorithms were used to improve sensitivity. Both EtBr staining and hybridization indicated a surprisingly uniform distribution of bacteria throughout the water column. However, the average cell size and staining intensity as well as the abundance of different morphotypes changed markedly within the chemocline. The constant overall cell counts thus concealed pronounced population shifts within the water column. Cells stained with a delta 385 probe (presumably sulfate-reducing bacteria) were detected at the chemocline at about 5 x 10(4) cells per ml, and this concentration increased to 2 x 10(5) cells per ml beneath the chemocline. A long slim rod-shaped bacterium was found in large numbers in the oxic part of the chemocline, whereas large ellipsoid cells dominated at greater depth. Application of selective probes for known genera of sulfate-reducing bacteria gave only low cell counts, and thus it was not possible to identify the dominant morphotypes of the sulfate-reducing community.

  7. Trans-Alaska pipeline

    SciTech Connect

    Not Available

    1991-07-01

    The Trans-Alaska Pipeline system transports nearly 25 percent of the nation's domestically produced crude oil. Since operations began in 1977, the system has delivered over 8 billion barrels of oil to Port Veldez for shipment. This paper reports that concerns have been raised about whether the system is meeting special engineering design and operations requirements imposed by federal and state regulators. GAO found that the five principal federal and state regulatory agencies have not pursued a systematic, disciplined, and coordinated approach to regulating the Trans-Alaska Pipeline System. Instead, these agencies have relied on the Alyeska Pipeline Service Company, which runs the system, to police itself. It was only after the Exxon Valdez spill and the discovery of corrosion that the regulators began to reevaluate their roles and focus on issues such as whether Alyeska's operating and maintenance procedures meet the pipelines, special engineering design and operating requirements, or whether Alyeska can adequately respond to a large oil spill. In January 1990, the regulators established a joint office to provide more effective oversight of the system. GAO believes that central leadership and a secured funding sources may help ensure that this office provides adequate oversight.

  8. Metamorphic facies map of Alaska

    SciTech Connect

    Dusel-Bacon, C.; O-Rourke, E.F.; Reading, K.E.; Fitch, M.R.; Klute, M.A.

    1985-04-01

    A metamorphic-facies of Alaska has been compiled, following the facies-determination scheme of the Working Group for the Cartography of the Metamorphic Belts of the World. Regionally metamorphosed rocks are divided into facies series where P/T gradients are known and into facies groups where only T is known. Metamorphic rock units also are defined by known or bracketed age(s) of metamorphism. Five regional maps have been prepared at a scale of 1:1,000,000; these maps will provide the basis for a final colored version of the map at a scale of 1:2,500,000. The maps are being prepared by the US Geological Survey in cooperation with the Alaska Division of Geological and Geophysical Surveys. Precambrian metamorphism has been documented on the Seward Peninsula, in the Baird Mountains and the northeastern Kuskokwim Mountains, and in southwestern Alaska. Pre-Ordovician metamorphism affected the rocks in central Alaska and on southern Prince of Wales Island. Mid-Paleozoic metamorphism probably affected the rocks in east-central Alaska. Most of the metamorphic belts in Alaska developed during Mesozoic or early Tertiary time in conjuction with accretion of many terranes. Examples are Jurassic metamorphism in east-central Alaska, Early Cretaceous metamorphism in the southern Brooks Range and along the rim of the Yukon-Kovyukuk basin, and late Cretaceous to early Tertiary metamorphism in the central Alaska Range. Regional thermal metamorphism was associated with multiple episodes of Cretaceous plutonism in southeastern Alaska and with early Tertiary plutonism in the Chugach Mountains. Where possible, metamorphism is related to tectonism. Meeting participants are encouraged to comment on the present version of the metamorphic facies map.

  9. The slow advance of a calving glacier: Hubbard Glacier, Alaska, U.S.A

    USGS Publications Warehouse

    Trabant, D.C.; Krimmel, R.M.; Echelmeyer, K.A.; Zirnheld, S.L.; Elsberg, D.H.

    2003-01-01

    Hubbard Glacier is the largest tidewater glacier in North America. In contrast to most glaciers in Alaska and northwestern Canada, Hubbard Glacier thickened and advanced during the 20th century. This atypical behavior is an important example of how insensitive to climate a glacier can become during parts of the calving glacier cycle. As this glacier continues to advance, it will close the seaward entrance to 50 km long Russell Fjord and create a glacier-dammed, brackish-water lake. This paper describes measured changes in ice thickness, ice speed, terminus advance and fjord bathymetry of Hubbard Glacier, as determined from airborne laser altimetry, aerial photogrammetry, satellite imagery and bathymetric measurements. The data show that the lower regions of the glacier have thickened by as much as 83 m in the last 41 years, while the entire glacier increased in volume by 14.1 km3. Ice speeds are generally decreasing near the calving face from a high of 16.5 m d-1 in 1948 to 11.5 m d-1 in 2001. The calving terminus advanced at an average rate of about 16 m a-1 between 1895 and 1948 and accelerated to 32 m a-1 since 1948. However, since 1986, the advance of the part of the terminus in Disenchantment Bay has slowed to 28 m a-1. Bathymetric data from the lee slope of the submarine terminal moraine show that between 1978 and 1999 the moraine advanced at an average rate of 32 m a-1, which is the same as that of the calving face.

  10. Polychlorinated dibenzo-p-dioxins and dibenzofurans in sediments and biota of the Saguenay Fjord and the St. Lawrence Estuary

    SciTech Connect

    Brochu, C.; Moore, S.; Pelletier, E.

    1995-12-31

    Sediment samples and marine organisms were collected in the Saguenay Fjord and at two selected sites of the St. Lawrence Estuary in 1991. Total PCDDs and total PCDFs ranged from 22 to 352 ng kg{sup {minus}1} and 29 to 188 ng kg{sup {minus}1}, respectively in Saguenay sediments, while total PCDFs reached, 287 ng kg{sup {minus}1} in Baie des Anglais, a small and deep bay of the St. Lawrence Estuary impacted by PCBs during the 1970s. All biological samples contained detectable amounts of chlorinated dibenzodioxins and dibenzofurans, apart from the North Atlantic cod (Gadus morhua). The highest concentrations (up to 59.7 ng kg{sup {minus}1} total PCDFs and 2.54 ng kg{sup {minus}1} 2,3,7,8T4CDD Equivalent (TCDD TEQ)) were observed in crab (Chionoecetes opilio) caught in Saguenay Fjord and in crab and whelk (Buccinwn undatwn) collected in Baie des Anglais. Nordic shrimp (Pandalus borealis) is less contaminated with a maximum total PCDDs and PCDFs concentration of 14.0 ng kg{sup {minus}1} and TCDD TEQ never exceeding 0.7 ng kg{sup {minus}1}. Greenland halibut (Reinhardtius hippoglossoides) caught in the Saguenay Fjord contained only 2,3,7,8 substituted congeners in their tissues leading to a low average TCDD TEQ of 1.66 ng kg{sup {minus}1}. Based upon this first series of results, benthic organisms and fish from the Saguenay Fjord and the north shore of the St. Lawrence Estuary are exposed to low levels of PCDDs and PCDFs, and carry tissue concentrations well below international guidelines for fisheries products.

  11. Chlorophyll-a thin layers in the Magellan fjord system: The role of the water column stratification

    NASA Astrophysics Data System (ADS)

    Ríos, Francisco; Kilian, Rolf; Mutschke, Erika

    2016-08-01

    Fjord systems represent hotspots of primary productivity and organic carbon burial. However, the factors which control the primary production in mid-latitude fjords are poorly understood. In this context, results from the first fine-scale measurements of bio-oceanographic features in the water column of fjords associated with the Strait of Magellan are presented. A submersible fluorescence probe (FP) was used to measure the Chlorophyll-a (Chl-a) concentration in situ, along with conductivity, temperature, hydrostatic pressure (depth) and dissolved oxygen (CTD-O2) of the water column. The Austral spring results of 14 FP-CTD-O2 profiles were used to define the vertical and horizontal patches of the fluorescent pigment distribution and their spatial relations with respect to the observed hydrographic features. Three zones with distinct water structures were defined. In all zones, the 'brown' spectral group (diatoms and dinoflagellates) predominated accounting for >80 wt% of the phytoplankton community. Thin layers with high Chl-a concentration were detected in 50% of the profiles. These layers harbored a substantial amount (30-65 wt%) of the phytoplankton biomass. Stratification was positively correlated to the occurrence of Chl-a thin layers. In stable and highly stratified water columns the integrated Chl-a concentration was higher and frequently located within thin layers whereas well mixed water columns displayed lower values and more homogeneous vertical distribution of Chl-a. These results indicate that mixing/stability processes are important factors accounting to the vertical distribution of Chl-a in Magellan fjords.

  12. Conceptual PHES-system models of the Aysén watershed and fjord (Southern Chile): testing a brainstorming strategy.

    PubMed

    Marín, Víctor H; Delgado, Luisa E; Bachmann, Pamela

    2008-09-01

    The use of brainstorming techniques for the generation of conceptual models, as the basis for the integrated management of physical-ecological-social systems (PHES-systems) is tested and discussed. The methodology is applied in the analysis of the Aysén fjord and watershed (Southern Chilean Coast). Results show that the proposed methods can be adequately used in management scenarios characterized by highly hierarchical, experts/non-experts membership.

  13. Dynamics of dissolved organic matter in fjord ecosystems: Contributions of terrestrial dissolved organic matter in the deep layer

    NASA Astrophysics Data System (ADS)

    Yamashita, Youhei; McCallister, S. Leigh; Koch, Boris P.; Gonsior, Michael; Jaffé, Rudolf

    2015-06-01

    Annually, rivers and inland water systems deliver a significant amount of terrestrial organic matter (OM) to the adjacent coastal ocean in both particulate and dissolved forms; however, the metabolic and biogeochemical transformations of OM during its seaward transport remains one of the least understood components of the global carbon cycle. This transfer of terrestrial carbon to marine ecosystems is crucial in maintaining trophic dynamics in coastal areas and critical in global carbon cycling. Although coastal regions have been proposed as important sinks for exported terrestrial materials, most of the global carbon cycling data, have not included fjords in their budgets. Here we present distributional patterns on the quantity and quality of dissolved OM in Fiordland National Park, New Zealand. Specifically, we describe carbon dynamics under diverse environmental settings based on dissolved organic carbon (DOC) depth profiles, oxygen concentrations, optical properties (fluorescence) and stable carbon isotopes. We illustrate a distinct change in the character of DOC in deep waters compared to surface and mid-depth waters. Our results suggest that, both, microbial reworking of terrestrially derived plant detritus and subsequent desorption of DOC from its particulate counterpart (as verified in a desorption experiment) are the main sources of the humic-like enriched DOC in the deep basins of the studied fjords. While it has been suggested that short transit times and protection of OM by mineral sorption may ultimately result in significant terrestrial carbon burial and preservation in fjords, our data suggests the existence of an additional source of terrestrial OM in the form of DOC generated in deep, fjord water.

  14. Water from land - fresh water outflow from glaciated and non-glaciated catchments into the Hornsund fjord, Svalbard

    NASA Astrophysics Data System (ADS)

    Nawrot, Adam; Wawrzyniak, Tomasz; Walczowski, Waldemar; Osuch, Marzena

    2016-04-01

    Freshwater processes in South Spitsbergen catchments are facing climate related alterations and issues, such as prolongation of the ablation seasons, water level changes and droughts. Snow accumulation and duration of snow cover in high latitude areas largely determine hydrological and periglacial processes, influencing flora, fauna and their ecology. Hydrological data from this part of the Arctic so far were sparse and major gaps remained in our understanding of freshwater distribution, regime, status and threats. From 2013 to 2015 as part of multidisciplinary and complex investigations within the framework of "AWAKE2 - Arctic Climate System Study of Ocean, Sea Ice and Glaciers Interactions in Svalbard Area" project, field measurements were conducted around Hornsund, the southernmost fjord of Spitsbergen. This was the first study of the fresh water and snow cover in such scale in this area and included spatial distribution of snow, together with water balance measurements in non-glaciated and glaciated catchments. During the fieldwork in Hornsund Fjord area, snow thickness and snow density have been measured in 350 and 50 points, respectively. Precipitation was measured in 6 points. Runoff was measured on 7 rivers in different glaciated (Ariedalen, Sofiedalen, Lorchbreen, Bautabreen, Gashamna) and non-glaciated (Fuglebekken, Lisbetdalen) catchments. Meteorological observations were conducted at the Hornsund Polish Polar Station and in the in the surroundings of Hornsund fjord. The results of this investigation show response of the freshwater hydrological processes to observed seasonal climatic variations in this area. Approximated water balance and known volume of fresh water outflow to the sea are the key components of understanding Arctic fjord ecosystem mechanisms. This is the first comprehensive investigation of the water balance in this region. Project AWAKE2 is funded by Norway Grants.

  15. The Saguenay Fjord, Quebec, Canada: Integrating marine geotechnical and geophysical data for spatial seismic slope stability and hazard assessment

    USGS Publications Warehouse

    Urgeles, R.; Locat, J.; Lee, H.J.; Martin, F.

    2002-01-01

    In 1996 a major flood occurred in the Saguenay region, Quebec, Canada, delivering several km3 of sediment to the Saguenay Fjord. Such sediments covered large areas of the, until then, largely contaminated fjord bottom, thus providing a natural capping layer. Recent swath bathymetry data have also shown that sediment landslides are widely present in the upper section of the Saguenay Fjord, and therefore, should a new event occur, it would probably expose the old contaminated sediments. Landslides in the Upper Saguenay Fjord are most probably due to earthquakes given its proximity to the Charlevoix seismic region and to that of the 1988 Saguenay earthquake. In consequence, this study tries to characterize the permanent ground deformations induced by different earthquake scenarios from which shallow sediment landslides could be triggered. The study follows a Newmark analysis in which, firstly, the seismic slope performance is assessed, secondly, the seismic hazard analyzed, and finally an evaluation of the seismic landslide hazard is made. The study is based on slope gradients obtained from EM1000 multibeam bathymetry data as well as water content and undrained shear strength measurements made in box and gravity cores. Ground motions integrating local site conditions were simulated using synthetic time histories. The study assumes the region of the 1988 Saguenay earthquake as the most likely source area for earthquakes capable of inducing large ground motions in the Upper Saguenay region. Accordingly, we have analyzed several shaking intensities to deduce that generalized sediment displacements will begin to occur when moment magnitudes exceed 6. Major displacements, failure, and subsequent landslides could occur only from earthquake moment magnitudes exceeding 6.75. ?? 2002 Elsevier Science B.V. All rights reserved.

  16. Temporal and spatial variations in lice numbers on salmon farms in the Hardanger fjord 2004-06.

    PubMed

    Heuch, P A; Olsen, R S; Malkenes, R; Revie, C W; Gettinby, G; Baillie, M; Lees, F; Finstad, B

    2009-01-01

    The long and narrow Hardanger fjord in western Norway has a high density of salmon farms and has had severe salmon lice, Lepeophtheirus salmonis, problems. In the years 2004-06, salmon lice numbers were recorded in selected salmon farms in the fjord as part of a larger research project. Most farm sites participated in a strategic control programme and were deloused between November and January in each year. The aim of the programme was to achieve a mean abundance of <0.3 adult female lice at this time and to minimize the infection pressure on wild smolts in the spring. Dedicated teams carried out detailed counting of lice on farmed fish in April-September each year. Temperature conditions were fairly similar throughout the fjord and amongst years, but wide variations in salinities were observed. The two innermost zones, B and C, had the lowest lice mean abundances, whereas the outermost zones, D and E, consistently had more lice. General linear model analyses showed that differences in adult female lice abundance between the zones were associated with differing levels of salinity and emamectin benzoate treatments strategically administered. Mean fish weight was significantly positively correlated with mean abundance of adult female lice.

  17. 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.

  18. Transport and sediment accumulation of sup 210 Pb and sup 137 Cs in two southeast Alaskan fjords

    SciTech Connect

    Sugai, S.F. )

    1991-05-01

    Sediment profiles of {sup 210}Pb and {sup 137}Cs in cores collected at increasing distances form the heads of Smeaton Bay and Boca de Quadra fjords indicate that watersheds influence the inventories of radioisotopes present and that the steep topographies of the fjords enhance sediment redistribution. Episodic deposition of terrestrially derived sediment was responsible for roughly 50% of the {sup 137}Cs and 45% of the {sup 210}Pb inventories in shallower (less than 180 m) locations in Wilson and Bakewell arms of Smeaton Bay. {sup 210}Pb sedimentation rates at shallower sites when corrected for episodic deposition were less than sedimentation rates obtained in the deep basins of the fjords where sediment focusing and increased primary productivity in the overlaying water column occur. Higher fluxes of dissolved Mn from surficial sediments and subsequent reoxidation in the overlying water may have enhanced scavenging of {sup 210}Pb in basin locatons resulting in higher inventories. Episodic events have occured frequently in Smeaton Bay and Boca de Quadra suggesting that steady-state conditions with respect to sedimenting particles can be achieved only when averaged over long time periods approaching the time over which {sup 137}Cs and {sup 210}Pb are useful.

  19. Differences between Arctic and Atlantic fjord systems on bioaccumulation of persistent organic pollutants in zooplankton from Svalbard.

    PubMed

    Hallanger, Ingeborg G; Ruus, Anders; Warner, Nicholas A; Herzke, Dorte; Evenset, Anita; Schøyen, Merete; Gabrielsen, Geir W; Borgå, Katrine

    2011-06-15

    Differences in bioaccumulation of persistent organic pollutants (POPs) between fjords characterized by different water masses were investigated by comparing POP concentrations, patterns and bioaccumulation factors (BAFs) in seven species of zooplankton from Liefdefjorden (Arctic water mass) and Kongsfjorden (Atlantic water mass), Svalbard, Norway. No difference in concentrations and patterns of POPs was observed in seawater and POM; however higher concentrations and BAFs for certain POPs were found in species of zooplankton from Kongsfjorden. The same species were sampled in both fjords and the differences in concentrations of POPs and BAFs were most likely due to fjord specific characteristics, such as ice cover and timing of snow/glacier melt. These confounding factors make it difficult to conclude on water mass (Arctic vs. Atlantic) specific differences and further to extrapolate these results to possible climate change effects on accumulation of POPs in zooplankton. The present study suggests that zooplankton do biomagnify POPs, which is important for understanding contaminant uptake and flux in zooplankton, though consciousness regarding the method of evaluation is important. PMID:21600630

  20. Population status of Kittlitz's Murrelet Brachyramphus brevirostris along the southern coast of the Alaska Peninsula

    USGS Publications Warehouse

    van Pelt, Thomas I.; Piatt, John F.

    2005-01-01

    The Kittlitz's murrelet (Brachyramphus brevirostris) is a rare seabird that nests in alpine terrain and generally forages near tidewater glaciers during the breeding season. An estimated 95% of the global population breeds in Alaska, with some unknown proportion breeding in the Russian Far East. A global population estimate using bestavailable data in the early 1990s was 20,000 individuals. However, recent survey data from two core areas (Prince William Sound and Glacier Bay) suggest that populations have declined by 75-90% during the past 10-20 years. In response to these declines, a coalition of environmental groups petitioned the USFWS in May 2001 to list the Kittlitz’s murrelet under the Endangered Species Act (ESA), and in 2004 Kittlitz’s Murrelet was declared a candidate species under the ESA. In 2005, BirdLife International classified the species as “critically endangered”. In 2002, we began a three-year project to examine population status and trend of Kittlitz’s Murrelets in areas where distribution and abundance were poorly known. Results from the 2002 field season, focused on the south coast of the Kenai Peninsula, suggested that the local population of Kittlitz’s Murrelets has declined by ca. 74% since 1986, with a current population of ca. 500 individuals. Here we present results from the 2003 field season when we surveyed Kittlitz’s Murrelets along the southern coast of the Alaska Peninsula. This is a large region that encompasses a substantial portion of the known range of the Kittlitz’s Murrelet, yet has never been surveyed rigorously for murrelets or any other non-colonial marine birds. During four weeks of surveys, we established a set of nearshore and offshore transects (over 825 linear kilometers in total) with a stratified sample design, combining random and systematically selected transects. From a total of 123 individuals seen on transects, we estimate a total population of 2265 (95% CI 1165-4405) Kittlitz’s Murrelets along

  1. Evolution of a trough-fan system: Scoresby Sund fjord, central-east Greenland

    NASA Astrophysics Data System (ADS)

    Pérez, Lara F.; Nielsen, Tove; Knutz, Paul C.; Kuijpers, Antoon; Damm, Volkmar

    2016-04-01

    The continental shelf along the east margin of Greenland is shaped by several, glacially carved transverse troughs that constitute the oceanward extension of the major fjords. Scoresby Sund is the most prominent fjord of central-east Greenland and separates Liverpool Land, to the north, from Blosseville Kyst to the south. Offshore of Scoresby Sund a large glacial trough mouth fan (TMF) has been built through successive phases of glacial advances. Morpho-structural and seismo-stratigraphic analyses of the Scoresby Sund TMF have been done using all Multichannel Seismic (MCS) profiles available in the area. The ODP site 987 of the leg 162 is located in the abyssal plain offshore of Scoresby Sund and was used for age estimations. The width of the continental shelf in the study area ranges from a 65 km narrow part along the Blosseville Kyst to 120 km off Scoresby Sund. The average water depth is shallower than 300 m, deepening to 600 m along Scoresby Sund glacial trough. Oceanwards a steep slope, seafloor falls into the 2250 m deep abyssal plain of the south Greenland Sea. The sedimentary cover displays maximum thickness along the middle continental shelf (2.8 s TWTT on average). Seven major stratigraphic discontinuities could be identified within the sedimentary record. They restrict eight major seismic units, named from 8 to 1, in upward stratigraphic order. The distribution and seismic facies of these units reveal the evolutionary sequence of the study area from early Cenozoic to Present. The lowest unit, Unit 8, is post-basalt to middle-late Miocene age and represents a pre-glacial depositional stage when tectonic events controlled the sedimentation. Deposition of Unit 7 occurred by late Miocene, revealing glacial-related deposits and ice-stream along Scoresby Sund fjord. Unit 6 was formed during early Pliocene by glacial advance over the continental shelf leading to strong erosive surfaces in the shelf area and Mass Transport Deposits (MTDs) in the northern abyssal

  2. Pockmarks in the fjords of western Svalbard and their implications on gas hydrate dissociation

    NASA Astrophysics Data System (ADS)

    Roy, S.; Senger, K.; Noormets, R.; Hovland, M.

    2012-04-01

    Shallow gas hydrate deposits in the Arctic regions can undergo rapid dissociation as a result of rising temperatures and/or decreasing pressure due to thawing permafrost seal releasing large amounts of methane into the water column and to the atmosphere. Svalbard is located within the zone of continuous permafrost. Periglacial and permafrost-related terrain features are widespread in areas not covered by glaciers. According to published data the thickness of permafrost at the coast is about 10-40 m, increasing to more than 450 m in the highlands. High resolution swath bathymetry data were used to systematically map the glacial landforms and pockmarks in the Isfjorden region. The pockmarks comprise randomly distributed circular and elliptical depressions. Their diameters range from 30 m to 242 m and the maximum depth is 11 m. Raised rims occur locally. Pockmark strings are located within glacial lineations formed during the Late Weichselian glaciation. The maximum water depth of the Isfjorden is 428 m and sea-bottom temperatures range from -2 to 5 °C. The extent and thickness of possible methane hydrate in Isfjorden has been calculated and the overlapping zones with potential pockmarks and glacial landforms in the fjord seafloor have been analysed in this study. Phase diagrams show that the stability field of methane hydrate is dependent on temperature, pressure and the composition of the hydrate-forming gas. Thermo-baric modeling indicates that 280 m of water depth is required for pure methane to potentially form a hydrate at 0 °C. The presence of NMHC (non-methane hydrocarbons: C1 to C5 alkanes) would require shallower water depths to form gas hydrates. Glacial ice cover would increase the load to the sedimentary column, increasing pressure on the underlying sediments. The temperature in the underlying sediments would also be lower due to the base of the ice which is at around 0-2 °C thereby increasing the potential for formation of gas hydrates. The

  3. Size and perspective in Alaska.

    PubMed

    Towle, Jim

    2006-01-01

    By far America's largest state, Alaska has only 350 members, so effective communication matters in overcoming distance. Alaska has led the way in direct reimbursement, diversity in leadership, member involvement, and a distinctive lifestyle for its practitioners. The tripartite structure of organized dentistry is crucial in building understanding the issues involved in providing oral health care to the members of this vast state. PMID:17585733

  4. Abundance of ringed seals (Pusa hispida) in the fjords of Spitsbergen, Svalbard, during the peak molting period

    USGS Publications Warehouse

    Krafft, B.A.; Kovacs, K.M.; Andersen, M.; Aars, J.; Lydersen, C.; Ergon, T.; Haug, T.

    2006-01-01

    Ringed seal (Pusa hispida) abundance in Spitsbergen, Svalbard, was estimated during the peak molting period via aerial, digital photographic surveys. A total of 9,145 images, covering 41.7%?100% of the total fast-ice cover (1,496 km2) of 18 different fjords and bays, were inspected for the presence of ringed seals. A total of 1,708 seals were counted, and when accounting for ice areas that were not covered by images, a total of 3,254 (95% CI: 3,071?3,449) ringed seals were estimated to be hauled out during the surveys. Extensive behavioral data from radio-tagged ringed seals (collected in a companion study) from one of the highest density fjords during the molting period were used to create a model that predicts the proportion of seals hauled out on any given date, time of day, and under various meteorological conditions. Applying this model to the count data from each fjord, we estimated that a total of 7,585 (95% CI: 6,332-9,085) ringed seals were present in the surveyed area during the peak molting period. Data on interannual variability in ringed seal abundance suggested higher numbers of seals in Van Keulenfjorden in 2002 compared to 2003, while other fjords with very stable ice cover showed no statistical differences. Poor ice conditions in general in 2002 probably resulted in seals from a wide area coming to Van Keulenfjorden (a large fjord with stable ice in 2002). The total estimated number of ringed seals present in the study area at the time of the survey must be regarded as a population index, or at least a minimum estimate for the area, because it does not account for individuals leaving and arriving, which might account for a considerable number of animals. The same situation is likely the case for many other studies reporting aerial census data for ringed seals. To achieve accurate estimates of population sizes from aerial surveys, more extensive knowledge of ringed seal behavior will be required.

  5. Alaska Athabascan stellar astronomy

    NASA Astrophysics Data System (ADS)

    Cannon, Christopher M.

    Stellar astronomy is a fundamental component of Alaska Athabascan cultures that facilitates time-reckoning, navigation, weather forecasting, and cosmology. Evidence from the linguistic record suggests that a group of stars corresponding to the Big Dipper is the only widely attested constellation across the Northern Athabascan languages. However, instruction from expert Athabascan consultants shows that the correlation of these names with the Big Dipper is only partial. In Alaska Gwich'in, Ahtna, and Upper Tanana languages the Big Dipper is identified as one part of a much larger circumpolar humanoid constellation that spans more than 133 degrees across the sky. The Big Dipper is identified as a tail, while the other remaining asterisms within the humanoid constellation are named using other body part terms. The concept of a whole-sky humanoid constellation provides a single unifying system for mapping the night sky, and the reliance on body-part metaphors renders the system highly mnemonic. By recognizing one part of the constellation the stargazer is immediately able to identify the remaining parts based on an existing mental map of the human body. The circumpolar position of a whole-sky constellation yields a highly functional system that facilitates both navigation and time-reckoning in the subarctic. Northern Athabascan astronomy is not only much richer than previously described; it also provides evidence for a completely novel and previously undocumented way of conceptualizing the sky---one that is unique to the subarctic and uniquely adapted to northern cultures. The concept of a large humanoid constellation may be widespread across the entire subarctic and have great antiquity. In addition, the use of cognate body part terms describing asterisms within humanoid constellations is similarly found in Navajo, suggesting a common ancestor from which Northern and Southern Athabascan stellar naming strategies derived.

  6. Alaska Interagency Ecosystem Health Work Group

    USGS Publications Warehouse

    Shasby, Mark

    2009-01-01

    The Alaska Interagency Ecosystem Health Work Group is a community of practice that recognizes the interconnections between the health of ecosystems, wildlife, and humans and meets to facilitate the exchange of ideas, data, and research opportunities. Membership includes the Alaska Native Tribal Health Consortium, U.S. Geological Survey, Alaska Department of Environmental Conservation, Alaska Department of Health and Social Services, Centers for Disease Control and Prevention, U.S. Fish and Wildlife Service, Alaska Sea Life Center, U.S. Environmental Protection Agency, and Alaska Department of Fish and Game.

  7. Operation IceBridge Alaska

    NASA Astrophysics Data System (ADS)

    Larsen, C.

    2015-12-01

    The University of Alaska Fairbanks (UAF) has flown LiDAR missions for Operation IceBridge in Alaska each year since 2009, expanding upon UAF's airborne laser altimetry program which started in 1994. These observations show that Alaska's regional mass balance is -75+11/-16 Gt yr-1 (1994-2013) (Larsen et al., 2015). A surprising result is that the rate of surface mass loss observed on non-tidewater glaciers in Alaska is extremely high. At these rates, Alaska contributes ~1 mm to global sea level rise every 5 years. Given the present lack of adequate satellite resources, Operation IceBridge airborne surveys by UAF are the most effective and efficient method to monitor this region's impact on global sea level rise. Ice depth measurements using radar sounding have been part of these airborne surveys since 2012. Many of Alaska's tidewater glaciers are bedded significantly below sea level. The depth and extent of glacier beds below sea level are critical factors in the dynamics of tidewater retreat. Improved radar processing tools are being used to predict clutter using forward simulation. This is essential to properly sort out true bed returns, which are often masked or obscured by valley wall returns. This presentation will provide an overview of the program, highlighting recent findings and observations from the most recent campaigns, and focusing on techniques used for the extrapolation of surface elevation changes to regional mass balances.

  8. Isolation and Physiological Characterization of Psychrophilic Denitrifying Bacteria from Permanently Cold Arctic Fjord Sediments (Svalbard, Norway)

    NASA Technical Reports Server (NTRS)

    Canion, Andy; Prakash, Om; Green, Stefan J.; Jahnke, Linda; Kuypers, Marcel M. M.; Kostka, Joel E.

    2013-01-01

    A large proportion of reactive nitrogen loss from polar sediments is mediated by denitrification, but microorganisms mediating denitrification in polar environments remain poorly characterized. A combined approach of most-probable-number (MPN) enumeration, cultivation and physiological characterization was used to describe psychrophilic denitrifying bacterial communities in sediments of three Arctic fjords in Svalbard (Norway). A MPN assay showed the presence of 10(sup 3)-10(sup 6) cells of psychrophilic nitrate-respiring bacteria g(sup -1) of sediment. Fifteen strains within the Proteobacteria were isolated using a systematic enrichment approach with organic acids as electron donors and nitrate as an electron acceptor. Isolates belonged to five genera, including Shewanella, Pseudomonas, Psychromonas (Gammaproteobacteria), Arcobacter (Epsilonproteobacteria) and Herminiimonas (Betaproteobacteria). All isolates were denitrifiers, except Shewanella, which exhibited the capacity for dissimilatory nitrate reduction to ammonium (DNRA). Growth from 0 to 40 degC demonstrated that all genera except Shewanella were psychrophiles with optimal growth below 15 degC, and adaptation to low temperature was demonstrated as a shift from primarily C16:0 saturated fatty acids to C16:1 monounsaturated fatty acids at lower temperatures. This study provides the first targeted enrichment and characterization of psychrophilic denitrifying bacteria from polar sediments, and two genera, Arcobacter and Herminiimonas, are isolated for the first time from permanently cold marine sediments.

  9. Structure of marine predator and prey communities along environmental gradients in a glaciated fjord

    USGS Publications Warehouse

    Renner, Martin; Arimitsu, Mayumi L.; Piatt, John F.

    2012-01-01

    Spatial patterns of marine predator communities are influenced to varying degrees by prey distribution and environmental gradients. We examined physical and biological attributes of an estuarine fjord with strong glacier influence to determine the factors that most influence the structure of predator and prey communities. Our results suggest that some species, such as walleye pollock (Theragra chalcogramma), black-legged kittiwake (Rissa tridactyla), and glaucous-winged gull (Larus glaucescens), were widely distributed across environmental gradients, indicating less specialization, whereas species such as capelin (Mallotus villosus), harbor seal (Phoca vitulina), and Kittlitz's murrelet (Brachyramphus brevirostris) appeared to have more specialized habitat requirements related to glacial influence. We found that upper trophic level communities were well correlated with their mid trophic level prey community, but strong physical gradients in photic depth, temperature, and nutrients played an important role in community structure as well. Mid-trophic level forage fish communities were correlated with the physical gradients more closely than upper trophic levels were, and they showed strong affinity to tidewater glaciers. Silica was closely correlated with the distribution of fish communities, the mechanisms of which deserve further study.

  10. In-Situ Observations of a Subglacial Outflow Plume in a Greenland Fjord

    NASA Astrophysics Data System (ADS)

    Mankoff, K. D.; Straneo, F.; Singh, H.; Das, S. B.

    2014-12-01

    We present oceanographic observations collected in and immediately outside of a buoyant, fresh, sediment-laden subglacial outflow plume rising up the marine-terminating front of Sarqardleq Glacier, Greenland (68.9 N, 50.4 W). Subglacial outflow plumes, associated with the discharge at depth of upstream glacial surface melt, entrain the relatively warm fjord waters and are correlated with enhanced submarine melt and increased calving. Few in-situ observations exist due to the challenges of making measurements at the calving front of glaciers. Our data were collected using a small boat, a helicopter, and a JetYak (a remote-controlled jet-ski-powered kayak). Temperature and salinity profiles in, around, and far from the plume are used to described its oceanographic properties, spatial extent, and temporal variability. This plume rises vertically up the ice front expanding laterally and away from the ice, over-shoots its stable isopycnal and reaches the surface. Its surface expression is identified by colder, saltier, sediment-laden water flowing at ~5 m/s away from the ice face. Within ~300 m from the ice it submerges as it seeks buoyant stability.

  11. Floating marine debris in fjords, gulfs and channels of southern Chile.

    PubMed

    Hinojosa, Iván A; Thiel, Martin

    2009-08-01

    Floating marine debris (FMD) is reported from all oceans. The bulk of FMD are plastics, which due to their longevity cause multiple negative impacts on wildlife and environment. Identifying the origins of FMD (land- or sea-based) is important to take the necessary steps to diminish their abundance. Using ship surveys we examined the abundance, composition and distribution of FMD during the years 2002-2005 in the fjords, gulfs and channels of southern Chile. Abundances of FMD were relatively high compared with other studies, ranging from 1 to 250 items km(-2). The majority (approximately 80%) of FMD was composed of styrofoam (expanded polystyrene), plastic bags and plastic fragments. Styrofoam, which is intensively used as flotation device by mussel farms, was very abundant in the northern region but rarely occurred in the southern region of the study area. Food sacks from salmon farms were also most common in the northern region, where approximately 85% of the total Chilean mussel and salmon harvest is produced. Plastic bags, which could be from land- or sea-based sources, were found throughout the entire study area. Our results indicate that sea-based activities (mussel farming and salmon aquaculture) are responsible for most FMD in the study area. In order to reduce FMDs in the environment, in addition to stronger legislation and identification of potential sources, we suggest environmental education programs and we encourage public participation (e.g. in beach surveys and clean-ups).

  12. Characterization of Streptomyces spp. Isolated from the Sea Surface Microlayer in the Trondheim Fjord, Norway

    PubMed Central

    Hakvåg, Sigrid; Fjærvik, Espen; Josefsen, Kjell D.; Ian, Elena; Ellingsen, Trond E.; Zotchev, Sergey B.

    2008-01-01

    The water surface microlayer is still poorly explored, although it has been shown to contain a high density of metabolically active bacteria, often called bacterioneuston. Actinomycetes from the surface microlayer in the Trondheim fjord, Norway, have been isolated and characterized. A total of 217 isolates from two separate samples morphologically resembling the genus Streptomyces have been further investigated in this study. Antimicrobial assays showed that about 80% of the isolates exhibited antagonistic activity against non-filamentous fungus, Gram-negative, and Gram-positive bacteria. Based on the macroscopic analyses and inhibition patterns from the antimicrobial assays, the sub-grouping of isolates was performed. Partial 16S rDNAs from the candidates from each subgroup were sequenced and phylogenetic analysis performed. 7 isolates with identical 16S rDNA sequences were further studied for the presence of PKS type I genes. Sequencing and phylogenetic analysis of the PKS gene fragments revealed that horizontal gene transfer between closely related species might have taken place. Identification of unique PKS genes in these isolates implies that de-replication can not be performed based solely on the 16S rDNA sequences. The results obtained in this study suggest that streptomycetes from the neuston population may be an interesting source for discovery of new antimicrobial agents. PMID:19172199

  13. Norwegian fjord sediments reveal NAO related winter temperature and precipitation changes of the past 2800 years

    NASA Astrophysics Data System (ADS)

    Faust, Johan; Fabian, Karl; Giraudeau, Jacques; Knies, Jochen

    2016-04-01

    The North Atlantic Oscillation (NAO) is the leading mode of atmospheric circulation variability in the North Atlantic region. Associated shifts of storm tracks, precipitation and temperature patterns affect energy supply and demand, fisheries and agricultural, as well as marine and terrestrial ecological dynamics. Long-term NAO reconstructions are crucial to better understand NAO variability in its response to climate forcing factors, and assess predictability and possible shifts associated with ongoing climate change. Fjord deposits have a great potential for providing high-resolution sedimentary records that reflect local terrestrial and marine processes and, therefore, offer unique opportunities for the investigation of sedimentological and geochemical climatically induced processes. A recent study of instrumental time series revealed NAO as main factor for a strong relation between winter temperature, precipitation and river discharge in central Norway over the past 50 years. Here we use the gained knowledge to establish the first high resolution NAO proxy record from marine sediments. By comparing geochemical measurements from a short sediment core with instrumental data we show that marine primary productivity proxies are sensitive to NAO changes. Conditioned on a stationary relation between our climate proxy and the NAO we establish the first high resolution NAO proxy record (NAO-TFJ) from marine sediments covering the past 2,800 years. The NAO-TFJ shows distinct co-variability with climate changes over Greenland, solar activity and Northern Hemisphere glacier dynamics as well as climatically associated paleo-demographic trends.

  14. Distribution, abundance, and habitat associations of a large bivalve (Panopea generosa) in a eutrophic, fjord estuary

    USGS Publications Warehouse

    Mcdonald, P. Sean; Essington, Timothy E.; Davis, Jonathan P.; Galloway, Aaron W.E.; Stevick, Bethany C.; Jensen, Gregory C.; Vanblaricom, Glenn R.; Armstrong, David A.

    2015-01-01

    Marine bivalves are important ecosystem constituents and frequently support valuable fisheries. In many nearshore areas, human disturbance—including declining habitat and water quality—can affect the distribution and abundance of bivalve populations, and complicate ecosystem and fishery management assessments. Infaunal bivalves, in particular, are frequently cryptic and difficult to detect; thus, assessing potential impacts on their populations requires suitable, scalable methods for estimating abundance and distribution. In this study, population size of a common benthic bivalve (the geoduck Panopea generosa) is estimated with a Bayesian habitat-based model fit to scuba and tethered camera data in Hood Canal, a fjord basin in Washington state. Densities declined more than two orders of magnitude along a north—south gradient, concomitant with patterns of deepwater dissolved oxygen, and intensity and duration of seasonal hypoxia. Across the basin, geoducks were most abundant in loose, unconsolidated, sand substrate. The current study demonstrates the utility of using scuba, tethered video, and habitat models to estimate the abundance and distribution of a large infaunal bivalve at a regional (385-km2) scale.

  15. Spatial and temporal distribution of chiral pesticides in Calanus spp. from three Arctic fjords.

    PubMed

    Carlsson, Pernilla; Warner, Nicholas A; Hallanger, Ingeborg G; Herzke, Dorte; Kallenborn, Roland

    2014-09-01

    Concentration and enantiomeric fractions (EFs) of chiral chlorinated pesticides (α-hexachlorocyclohexane (α-HCH), trans-, cis- and oxychlordane) were determined in Arctic zooplankton, mainly Calanus spp. collected in the period 2007-11 from Svalbard fjords and open pack-ice. The temporal and spatial enantiomer distribution varied considerably for all species and chiral pesticides investigated. An overall enantiomeric excess of (+)-oxychlordane (EF 0.53-0.86) were observed. Cis-chlordane was close to racemic (EF 0.46-0.55), while EF for trans-chlordane varied between 0.29 and 0.55, and between 0.38 and 0.59 for α-HCH. The biodegradation potential for trans-chlordane was higher compared to cis-chlordane. The comprehensive statistical evaluation of the data set revealed that the EF distribution of α-HCH was affected by ice cover to a higher extent compared to cis-chlordane. Potential impact from benthic processes on EFs in zooplankton is an interesting feature and should be further investigated. Enantiomeric selective analyses may be a suitable tool for investigations of climate change related influences on Arctic ecosystems. PMID:24951967

  16. Spatial and temporal distribution of chiral pesticides in Calanus spp. from three Arctic fjords.

    PubMed

    Carlsson, Pernilla; Warner, Nicholas A; Hallanger, Ingeborg G; Herzke, Dorte; Kallenborn, Roland

    2014-09-01

    Concentration and enantiomeric fractions (EFs) of chiral chlorinated pesticides (α-hexachlorocyclohexane (α-HCH), trans-, cis- and oxychlordane) were determined in Arctic zooplankton, mainly Calanus spp. collected in the period 2007-11 from Svalbard fjords and open pack-ice. The temporal and spatial enantiomer distribution varied considerably for all species and chiral pesticides investigated. An overall enantiomeric excess of (+)-oxychlordane (EF 0.53-0.86) were observed. Cis-chlordane was close to racemic (EF 0.46-0.55), while EF for trans-chlordane varied between 0.29 and 0.55, and between 0.38 and 0.59 for α-HCH. The biodegradation potential for trans-chlordane was higher compared to cis-chlordane. The comprehensive statistical evaluation of the data set revealed that the EF distribution of α-HCH was affected by ice cover to a higher extent compared to cis-chlordane. Potential impact from benthic processes on EFs in zooplankton is an interesting feature and should be further investigated. Enantiomeric selective analyses may be a suitable tool for investigations of climate change related influences on Arctic ecosystems.

  17. Modelling subglacial discharge and its influence on ocean heat transport in Arctic fjords

    NASA Astrophysics Data System (ADS)

    Bendtsen, Jørgen; Mortensen, John; Rysgaard, Søren

    2015-11-01

    Tidewater outlet glaciers are directly connected to the ocean via ice walls or floating shelves. Melting and freezing of ice, runoff, englacial, and subglacial discharge of freshwater and ocean heat transport are therefore potential feedback processes between glacial ice flow and ocean circulation. Subglacial discharge occurs at the base of tidewater glacier outlets where out-flowing freshwater forms a convective buoyant plume ascending close to the glacier face and, due to entrainment, transports relatively warm and saline ambient bottom water up towards the surface. Plume dynamics, typically occurring at sub-grid scales in regional ocean models, therefore has to be parameterized in areas where ice-ocean interactions occur, as for example in Arctic fjords. Here, we develop and analyze a new simple boundary condition of subglacial discharge where entrainment-induced transport between the subsurface and surface layer is described. A sensitivity study showed that subglacial discharge increased ocean heat transport near the glacier whereas the impact from plume-entrainment became relatively small further from the glacier. Subglacial discharge was shown to have a significant influence on surface concentrations. The impact from subglacial discharge was demonstrated in a regional model of Godthåbsfjord (64°N), located at the west coast of Greenland, where surface concentrations near the glacier were shown to be sensitive to subglacial discharge in accordance with observations.

  18. Geographic risk factors for inter-river dispersal of Gyrodactylus salaris in fjord systems in Norway.

    PubMed

    Jansen, Peder A; Matthews, Louise; Toft, Nils

    2007-02-28

    Gyrodactylus salaris has been recorded in 46 Norwegian rivers since 1975 and is considered a threat to Atlantic salmon stocks. The primary introductions of G. salaris (primary infected rivers) have been accounted for by specific events, as reported in the literature. The parasite has subsequently dispersed to adjacent localities (secondary infected rivers). The objective of this paper is to address the occurrence of secondary infections by examining the hypothesis of inter-river dispersal of G. salaris. A dispersal model for the secondary river infections via migrating infected fish is proposed. Due to the limited tolerance of G. salaris to salinity, both freshwater inflow to dispersal pathways and dispersal distance were expected to influence the probability of inter-river dispersal. Eighteen rivers were categorised as primary infected rivers, 28 as secondary infected rivers, and 54 as rivers at risk. Four risk factors: the log10 freshwater inflow; the dispersal distance; the time at risk; and the salmon harvest were combined in a multi-variable logistic regression model of the probability of secondary infection. The final multi-variable model included log10 freshwater inflow (Wald chi-square = 9.93) and dispersal distance (Wald chi-square = 6.48). Receiver operating characteristic analyses of the final model supported freshwater inflow as a strong predictor of G. salaris infection status. The strong influence of the freshwater inflow on the probability of secondary infection adds further support to the hypothesis of inter-river dispersal of G. salaris through fjords. PMID:17432043

  19. 75 FR 76957 - Fisheries of the Exclusive Economic Zone Off Alaska; North Pacific Halibut and Sablefish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-10

    ... cost recovery program (65 FR 14919), which are set forth at Sec. 679.45. Under the regulations, an IFQ..., Kenai River, Alitak, Kodiak, Port Bailey, Nikiski, Ninilchik, Old Harbor, Palmer, Sand Point,...

  20. Improving Student Achievement in Alaska. Alaska Goals 2000 Annual Report, 1997-98.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau.

    Alaska Goals 2000 is part of a coordinated, statewide effort to improve public education for all students in Alaska. In 1997-1998, 90% of Alaska's federal funding was used to fund grants to local school districts, and 10% was used to fund state-level activities through the Alaska Department of Education. During 1997-1998, curriculum frameworks and…

  1. Seasonal and Latitudinal Variations in Dissolved Methane from 42 Lakes along a North-South Transect in Alaska

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Armando Sepulveda-Jauregui,* Katey M. Walter Anthony,* Karla Martinez-Cruz,* ** 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. Northern lakes are important reservoirs and sources to the atmosphere of methane (CH4), a potent greenhouse gas. It is estimated that northern lakes (> 55 °N) contribute about 20% of the total global lake methane emissions, and that emissions from these lakes will increase with climate warming. Temperature rise enhances methane production directly by providing the kinetic energy to methanogenesis, and indirectly by supplying organic matter from thawing permafrost. Warmer lakes also store less methane since methane's solubility is inversely related to temperature. Alaskan lakes are located in three well-differentiated permafrost classes: yedoma permafrost with high labile carbon stocks, non-yedoma permafrost with lower carbon stocks, and areas without permafrost, also with generally lower carbon stocks. We sampled dissolved methane from 42 Alaskan lakes located in these permafrost cover classes along a north-south Alaska transect from Prudhoe Bay to the Kenai Peninsula during open-water conditions in summer 2011. We sampled 26 of these lakes in April, toward the end of the winter ice-covered period. Our results indicated that the largest dissolved methane concentrations occurred in interior Alaska thermokarst lakes formed in yedoma-type permafrost during winter and summer, with maximal concentrations of 17.19 and 12.76 mg L-1 respectively. In these lakes, emission of dissolved gases as diffusion during summer and storage release in spring were 18.4% and 17.4% of the annual emission budget, while ebullition (64.2 %) comprised the rest. Dissolved oxygen was inversely correlated with dissolved methane concentrations in both seasons; the

  2. Alaska GeoFORCE, A New Geologic Adventure in Alaska

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2011-12-01

    RAHI, the Rural Alaska Honors Institute is a statewide, six-week, summer college-preparatory bridge program at the University of Alaska Fairbanks for Alaska Native and rural high school juniors and seniors. A program of rigorous academic activity combines with social, cultural, and recreational activities. Students are purposely stretched beyond their comfort levels academically and socially to prepare for the big step from home or village to a large culturally western urban campus. This summer RAHI is launching a new program, GeoFORCE Alaska. This outreach initiative is designed to increase the number and diversity of students pursuing STEM degree programs and entering the future high-tech workforce. It uses Earth science as the hook because most kids get excited about dinosaurs, volcanoes and earthquakes, but it includes physics, chemistry, math, biology and other sciences. Students will be recruited, initially from the Arctic North Slope schools, in the 8th grade to begin the annual program of approximately 8 days, the summer before their 9th grade year and then remain in the program for all four years of high school. They must maintain a B or better grade average and participate in all GeoFORCE events. The carrot on the end of the stick is an exciting field event each summer. Over the four-year period, events will include trips to Fairbanks, Arizona, Oregon and the Appalachians. All trips are focused on Earth science and include a 100+ page guidebook, with tests every night culminating with a final exam. GeoFORCE Alaska is being launched by UAF in partnership with the University of Texas at Austin, which has had tremendous success with GeoFORCE Texas. GeoFORCE Alaska will be managed by UAF's long-standing Rural Alaska Honors Insitute (RAHI) that has been successfully providing intense STEM educational opportunities for Alaskan high school students for almost 30 years. The Texas program, with adjustments for differences in culture and environment, will be

  3. Diverse Approaches USED to Characterize the Earthquake and Tsunami Hazards Along the Southern Alaska Continental Margin

    NASA Astrophysics Data System (ADS)

    Haeussler, P. J.; Witter, R. C.; Liberty, L. M.; Brothers, D. S.; Briggs, R. W.; Armstrong, P. A.; Freymueller, J. T.; Parsons, T.; Ryan, H. F.; Lee, H. J.; Roland, E. C.

    2014-12-01

    Earthquakes and tsunamis are the principal geohazards of southern Alaska. The entire margin has ruptured in megathrust earthquakes, including the M9.2 1964 event, and these earthquakes have launched deadly local and trans-Pacific tsunamis. Tsunamis have been by far the largest killer in these earthquakes. Moreover, the subduction zone displays a range in locking behavior from completely locked beneath Prince William Sound, to ­­­­nearly freely slipping beneath the Shumagin Islands. Characterizing earthquake-related tsunami sources requires a diverse set of methods, and we discuss several examples. One important source for tsunamis is from megathrust splay faults. The Patton Bay splay fault system ruptured during the 1964 earthquake and generated a tsunami that impacted coastlines tens of minutes after the earthquake. A combination of multibeam mapping, high-resolution and crustal-scale seismic data, thermochronology, and detrital zircon geochronology show focused exhumation along this splay fault system for the last 2-3 Ma. Moreover, this long term pattern of exhumation mimics the pattern of uplift in 1964. Submarine landslides are another example of a tsunami source. Numerous devastating slides were triggered by the 1964 earthquake. Multibeam bathymetry, bathymetry difference maps, high-resolution seismic data, and records of paleotsunamis in coastal marshes reveal a long history of submarine landsliding in the coastal fjords of Alaska. The Little Ice Age appears to have had a significant influence on the submarine landslides in the 1964 earthquake through increased sediment production, transport to fjord margins, and, locally, compaction by glacier advances. Glacial retreat before 1964 gave rise to over-steepened slopes susceptible to dynamic failure. Numerous blocks in the submarine landslides were particularly effective in generating high tsunami run up. Finally, regional tectonic displacements of the seafloor have launched trans-Pacific tsunamis. Coastal

  4. Alaska Native Education Study: A Statewide Study of Alaska Native Values and Opinions Regarding Education in Alaska.

    ERIC Educational Resources Information Center

    McDowell Group, Juneau, AK.

    This document contains four reports detailing a four-phase research project on Alaska Natives' attitudes and values toward education. A literature review examines the history of Native education in Alaska, issues in research on American Indian and Alaska Native education, dropout studies, student assessment, language and culture, learning styles,…

  5. Profile: American Indian/Alaska Native

    MedlinePlus

    ... million American Indians and Alaska Natives. Typically, this urban clientele has less accessibility to hospitals; health clinics ... IHS and tribal health programs. Studies on the urban American Indian and Alaska Native population have documented ...

  6. Coalbed methane, Cook Inlet, south-central Alaska: A potential giant gas resource

    USGS Publications Warehouse

    Montgomery, S.L.; Barker, C.E.

    2003-01-01

    Cook Inlet Basin of south-central Alaska is a forearc basin containing voluminous Tertiary coal deposits with sufficient methane content to suggest a major coalbed gas resource. Coals ranging in thickness from 2 to 50 ft (0.6 to 15 m) and in gas content from 50 to 250 scf/ton (1.6 to 7.8 cm2/g) occur in Miocene-Oligocene fluvial deposits of the Kenai Group. These coals have been identified as the probable source of more than 8 tcf gas that has been produced from conventional sandstone reservoirs in the basin. Cook Inlet coals can be divided into two main groups: (1) those of bituminous rank in the Tyonek Formation that contain mainly thermogenic methane and are confined to the northeastern part of the basin (Matanuska Valley) and to deep levels elsewhere; and (2) subbituminous coals at shallow depths (<5000 ft [1524 m]) in the Tyonek and overlying Beluga formations, which contain mainly biogenic methane and cover most of the central and southern basin. Based on core and corrected cuttings-desorption analyses, gas contents average 230 scf/ton (7.2 cm2/g) for bituminous coals and 80 scf/ton (2.5 cm2/g) for subbituminous coals. Isotherms constructed for samples of both coal ranks suggest that bituminous coals are saturated with respect to methane, whereas subbituminous coals at shallow depths along the eroded west-central basin margin are locally unsaturated. A preliminary estimate of 140 tcf gas in place is derived for the basin.

  7. Malaspina Glacier, Alaska

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite covers an area of 55 by 40 kilometers (34 by 25 miles) over the southwest part of the Malaspina Glacier and Icy Bay in Alaska. The composite of infrared and visible bands results in the snow and ice appearing light blue, dense vegetation is yellow-orange and green, and less vegetated, gravelly areas are in orange. According to Dr. Dennis Trabant (U.S. Geological Survey, Fairbanks, Alaska), the Malaspina Glacier is thinning. Its terminal moraine protects it from contact with the open ocean; without the moraine, or if sea level rises sufficiently to reconnect the glacier with the ocean, the glacier would start calving and retreat significantly. ASTER data are being used to help monitor the size and movement of some 15,000 tidal and piedmont glaciers in Alaska. Evidence derived from ASTER and many other satellite and ground-based measurements suggests that only a few dozen Alaskan glaciers are advancing. The overwhelming majority of them are retreating.

    This ASTER image was acquired on June 8, 2001. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next six years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along-term research and

  8. Trends in Alaska's People and Economy.

    ERIC Educational Resources Information Center

    Leask, Linda; Killorin, Mary; Martin, Stephanie

    This booklet provides data on Alaska's population, economy, health, education, government, and natural resources, including specific information on Alaska Natives. Since 1960, Alaska's population has tripled and become more diverse, more stable, older, less likely to be male or married, and more concentrated. About 69 percent of the population…

  9. Alaska Pipeline Insulation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Crude oil moving through the 800-mile Trans-Alaska Pipeline must be kept at a relatively high temperature, about 180 degrees Fahrenheit, to maintain the fluidity of the oil. In Arctic weather, that demands highly effective insulation. General Electric Co.'s Space Division, Valley Forge, Pennsylvania, provided it with a spinoff product called Therm-O-Trol. Shown being installed on the pipeline, Therm-O-Trol is a metal-bonded polyurethane foam especially formulated for Arctic insulation. A second GE spinoff product, Therm-O-Case, solved a related problem involved in bringing hot crude oil from 2,000-foot-deep wells to the surface without transferring oil heat to the surrounding permafrost soil; heat transfer could melt the frozen terrain and cause dislocations that might destroy expensive well casings. Therm-O-Case is a double-walled oil well casing with multi-layered insulation which provides an effective barrier to heat transfer. Therm-O-Trol and Therm-O-Case are members of a family of insulating products which stemmed from technology developed by GE Space Division in heat transferlthermal control work on Gemini, Apollo and other NASA programs.

  10. Alexander Archipelago, Southeastern Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    West of British Columbia, Canada, and south of the Yukon Territory, the southeastern coastline of Alaska trails off into the islands of the Alexander Archipelago. The area is rugged and contains many long, U-shaped, glaciated valleys, many of which terminate at tidewater. The Alexander Archipelago is home to Glacier Bay National Park. The large bay that has two forks on its northern end is Glacier Bay itself. The eastern fork is Muir inlet, into which runs the Muir glacier, named for the famous Scottish-born naturalist John Muir. Glacier Bay opens up into the Icy Strait. The large, solid white area to the west is Brady Icefield, which terminates at the southern end in Brady's Glacier. To locate more interesting features from Glacier Bay National Park, take a look at the park service map. As recently as two hundred years ago, a massive ice field extended into Icy Strait and filled the Glacier Bay. Since that time, the area has experienced rapid deglaciation, with many large glaciers retreating 40, 60, even 80 km. While temperatures have increased in the region, it is still unclear whether the rapid recession is part of the natural cycle of tidewater glaciers or is an indicator of longer-term climate change. For more on Glacier Bay and climate change, read an online paper by Dr. Dorothy Hall, a MODIS Associate Science Team Member. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  11. Alaska Energy Inventory Project: Consolidating Alaska's Energy Resources

    NASA Astrophysics Data System (ADS)

    Papp, K.; Clough, J.; Swenson, R.; Crimp, P.; Hanson, D.; Parker, P.

    2007-12-01

    Alaska has considerable energy resources distributed throughout the state including conventional oil, gas, and coal, and unconventional coalbed and shalebed methane, gas hydrates, geothermal, wind, hydro, and biomass. While much of the known large oil and gas resources are concentrated on the North Slope and in the Cook Inlet regions, the other potential sources of energy are dispersed across a varied landscape from frozen tundra to coastal settings. Despite the presence of these potential energy sources, rural Alaska is mostly dependent upon diesel fuel for both electrical power generation and space heating needs. At considerable cost, large quantities of diesel fuel are transported to more than 150 roadless communities by barge or airplane and stored in large bulk fuel tank farms for winter months when electricity and heat are at peak demands. Recent increases in the price of oil have severely impacted the price of energy throughout Alaska, and especially hard hit are rural communities and remote mines that are off the road system and isolated from integrated electrical power grids. Even though the state has significant conventional gas resources in restricted areas, few communities are located near enough to these resources to directly use natural gas to meet their energy needs. To address this problem, the Alaska Energy Inventory project will (1) inventory and compile all available Alaska energy resource data suitable for electrical power generation and space heating needs including natural gas, coal, coalbed and shalebed methane, gas hydrates, geothermal, wind, hydro, and biomass and (2) identify locations or regions where the most economic energy resource or combination of energy resources can be developed to meet local needs. This data will be accessible through a user-friendly web-based interactive map, based on the Alaska Department of Natural Resources, Land Records Information Section's (LRIS) Alaska Mapper, Google Earth, and Terrago Technologies' Geo

  12. Calculating Freshwater Input from Iceberg Melt in Greenlandic Fjords by Combining In Situ Observations of Iceberg Movement with High Resolution Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Sulak, D. J.; Sutherland, D.; Stearns, L. A.; Hamilton, G. S.

    2015-12-01

    Understanding fjord circulation in Greenland's outlet glacial fjords is crucial to explaining recent temporal and spatial variability in glacier dynamics, as well as freshwater transport on the continental shelf. The fjords are commonly assumed to exhibit a plume driven circulation that draws in warmer and saltier Atlantic-origin water toward the glacier at depth. Freshwater input at glacier termini directly drives this circulation and significantly influences water column stratification, which indirectly feeds back on the plume driven circulation. Previous work has focused on freshwater inputs from surface runoff and submarine melting, but the contribution from iceberg melt, a potentially important freshwater source, has not been quantified. Here, we develop a new technique combining in situ observations of movement from iceberg-mounted GPS units with multispectral satellite imagery from Landsat 8. The combination of datasets allows us to examine the details of iceberg movement and quantify mean residence times in a given fjord. We then use common melt rate parameterizations to estimate freshwater input for a given iceberg, utilizing novel satellite-derived iceberg distributions to scale up to a fjord-wide freshwater contribution. We apply this technique to Rink Isbræ and Kangerlussuup Sermia in west Greenland, and Helheim Glacier in southeast Greenland. The analysis can be rapidly expanded to look at other systems as well as seasonal and interannual changes in how icebergs affect the circulation and stratification of Greenland's outlet glacial fjords. Ultimately, this work will lead to a more complete understanding of the wide range of factors that control the observed regional variability in Greenland's glaciers.

  13. Modern sedimentation in a rapidly warming fjord: Potter Cove, King George Island, Antarctica

    NASA Astrophysics Data System (ADS)

    Hass, H. C.; Kuhn, G.; Wittenberg, N.; Wölfl, A.

    2012-04-01

    The northern Antarctic Peninsula belongs to the fastest warming regions on earth. The winter-warming trend was strong and stable over the past 70 years. As a result, Potter Cove, a small fjord that opens into Maxwell Bay (King George Island, South Shetland Islands), shows significant environmental change. A former tidewater glacier (Fourcade Glacier) has retreated onto land exposing bedrock such as a small island close to the glacier front. It is suggested that the warming trend triggered excessive discharge of sediment-laden meltwaters in the form of turbid surface waters. The hypothesis for this study is that very fine-grained materials are present in Potter Cove and that meltwater plumes that exit Potter Cove can be traced downstream in the form of fans of fine-grained materials. In this study we investigate the modern sedimentation patterns in Potter Cove using hydroacoustics and seafloor samples to compare that with conditions from the past as recorded in sediment cores. Surface grain-size distributions reveal a distinct textural pattern in Potter Cove. Cluster analysis suggests 7 classes of sediment types. Four of them are unimodal, three classes show fine-skewed distributions with tendencies to bimodality. The finer sediment classes are found in the central inner part of the cove. The finest class (mode at 16 µm) forms only a small patch in the shelter of a small island. Sediments from close to the glacier front appear to be slightly depleted in fine-grained materials. From the glacier front to the outer fjord the sediments show influence of current sorting, i.e. the coarser mode becomes more significant and sorting increases. A sediment core from the deeper outer basin of Potter Cove reveals only one of the better-sorted, coarser classes that appears to form on the way from the glacier into the basin. There are 5 long sediment cores located less than 10 km off the mouth of Potter Cove in Maxwell Bay. All of which reveal sediments that belong either to the

  14. A management tool for assessing aquaculture environmental impacts in Chilean Patagonian Fjords: integrating hydrodynamic and pellets dispersion models.

    PubMed

    Tironi, Antonio; Marin, Víctor H; Campuzano, Francisco J

    2010-05-01

    This article introduces a management tool for salmon farming, with a scope in the local sustainability of salmon aquaculture of the Aysen Fjord, Chilean Patagonia. Based on Integrated Coastal Zone Management (ICZM) principles, the tool combines a large 3-level nested hydrodynamic model, a particle tracking module and a GIS application into an assessment tool for particulate waste dispersal of salmon farming activities. The model offers an open source alternative to particulate waste modeling and evaluation, contributing with valuable information for local decision makers in the process of locating new facilities and monitoring stations. PMID:20333379

  15. A Management Tool for Assessing Aquaculture Environmental Impacts in Chilean Patagonian Fjords: Integrating Hydrodynamic and Pellets Dispersion Models

    NASA Astrophysics Data System (ADS)

    Tironi, Antonio; Marin, Víctor H.; Campuzano, Francisco J.

    2010-05-01

    This article introduces a management tool for salmon farming, with a scope in the local sustainability of salmon aquaculture of the Aysen Fjord, Chilean Patagonia. Based on Integrated Coastal Zone Management (ICZM) principles, the tool combines a large 3-level nested hydrodynamic model, a particle tracking module and a GIS application into an assessment tool for particulate waste dispersal of salmon farming activities. The model offers an open source alternative to particulate waste modeling and evaluation, contributing with valuable information for local decision makers in the process of locating new facilities and monitoring stations.

  16. Aragonite saturation states and pH in western Norwegian fjords: seasonal cycles and controlling factors, 2005-2009

    NASA Astrophysics Data System (ADS)

    Omar, Abdirahman M.; Skjelvan, Ingunn; Rune Erga, Svein; Olsen, Are

    2016-07-01

    The uptake of anthropogenic carbon dioxide (CO2) by the ocean leads to a process known as ocean acidification (OA), which lowers the aragonite saturation state (ΩAr) and pH, and this is poorly documented in coastal environments including fjords due to lack of appropriate observations.

    Here we use weekly underway data from the Voluntary Observing Ships (VOS) program covering the period 2005-2009 combined with data from research cruises to estimate ΩAr and pH values in several adjacent western Norwegian fjords, and to evaluate how seawater CO2 chemistry drives their variations in response to physical and biological factors.

    The OA parameters in the surface waters of the fjords are subject to strong seasonal and spatially coherent variations. These changes are governed by the seasonal changes in temperature, salinity, formation and decay of organic matter, and vertical mixing with deeper, carbon-rich coastal water. Annual mean pH and ΩAr values were 8.13 and 2.21, respectively. The former varies from minimum values ( ≈ 8.05) in late December - early January to maximum values of around 8.2 during early spring (March-April) as a consequence of the phytoplankton spring bloom, which reduces dissolved inorganic carbon (DIC). In the following months, pH decreases in response to warming. This thermodynamic decrease in pH is reinforced by the deepening of the mixed layer, which enables carbon-rich coastal water to reach the surface, and this trend continues until the low winter values of pH are reached again. ΩAr, on the other hand, reaches its seasonal maximum (> 2.5) in mid- to late summer (July-September), when the spring bloom is over and pH is decreasing. The lowest ΩAr values ( ≈ 1.3-1.6) occur during winter (January-March), when both pH and sea surface temperature (SST) are low and DIC is its highest. Consequently, seasonal ΩAr variations align with those of SST and salinity normalized DIC (nDIC).

    We demonstrate that

  17. A dynamic CSTT model for the effects of added nutrients in Loch Creran, a shallow fjord

    NASA Astrophysics Data System (ADS)

    Laurent, Céline; Tett, Paul; Fernandes, Teresa; Gilpin, Linda; Jones, Ken

    2006-07-01

    Despite a tendency for the complexity of physical-biological models to increase, simple coupled models remain useful for some applications and can provide insights into crucial links between physical and biological processes. This argument is illustrated with an account of a simple 3-box model intended to help assess the capacity of fjords to assimilate nutrients from fish farms. The model, a dynamic version of the UK "Comprehensive Studies Task Team" (CSTT) steady-state model for eutrophication, was applied to Loch Creran (Scottish Western Highlands) and was implemented using Stella 8 and tested using historical data from 1975 (before the installation of a salmon farm) and field data collected in 2003, during the period of operation of the farm. The model's biological state variables are chlorophyll, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), and it includes a simple run-off model to convert rainfall into river discharge. The physical processes involved in exchange between the loch and the adjacent waters of the Firth of Lorne were parameterised as a constant daily exchange rate. Between 1975 and 2003, local inputs of nutrient increased but, despite this, there was little apparent increase in nutrient concentrations in the loch, and observed chlorophyll concentrations decreased substantially. Model simulations of chlorophyll and DIN agreed well with observations in 1975, as did DIN simulations in 2003. However, simulated chlorophyll was overestimated in 2003. Some of the agreement between observations and simulations come from the use of observed boundary conditions to force the model. However, even when boundary conditions are subtracted from simulations and observations, the simulations in most cases retain a significant correlation with observations, demonstrating that the model's 'interior' processes do add to its ability to replicate conditions in the loch.

  18. The silica cycle in a Northeast Pacific fjord; the role of biological resuspension

    NASA Astrophysics Data System (ADS)

    Katz, Timor; Yahel, Gitai; Tunnicliffe, Verena; Herut, Barak; Whitney, Frank; Snelgrove, Paul V. R.; Lazar, Boaz

    2016-09-01

    This study is a quantitative assessment of the role fish-induced bio-resuspension plays in the silica cycle of coastal waters. We used new, published and archived oceanographic data to construct a comprehensive silica budget for Saanich Inlet (Vancouver Island, Canada), a highly productive Northeast Pacific fjord, where siliceous diatoms dominate primary productivity. Anoxia in the deep water of the inlet persists during most of the year, precluding animal life, whereas abundant groundfish continuously rework and resuspend bottom sediments in the shallower, oxygenated margins. This resuspension transfers settled biogenic silica fragments from the sediment, where they are immersed in porewater that is rich with dissolved silica, to the overlying water, where the much lower concentrations accelerate their dissolution rate. The budget shows that Saanich Inlet sediments constitute a sink for approximately 250 × 106 mol Si y-1. Most of this Si enters the inlet in advected, siliceous phytoplankton. Sediment resuspension by groundfish in the oxygenated margins of Saanich Inlet generates about 50% of the total flux of dissolved silica from the inlet seafloor. This resuspension also facilitates a massive transport of biogenic silica from the margins to the anoxic basin, where approximately 90% of all the biogenic silica is buried. The excess dissolution caused by fish activity reduces the burial efficiency of biogenic silica in the entire inlet sediments by about 20%. This case study emphasizes the link between the silica cycle and groundfish activity. Based on this study and because biological resuspension occurs in most regions of the ocean, we recommend that it will be taken into account when budgeting the silica cycle, and potentially other geochemical cycles, in marine environments.

  19. Implementation of marine spatial planning in shellfish aquaculture management: modeling studies in a Norwegian fjord.

    PubMed

    Filgueira, Ramon; Grant, Jon; Strand, Øivind

    2014-06-01

    Shellfish carrying capacity is determined by the interaction of a cultured species with its ecosystem, which is strongly influenced by hydrodynamics. Water circulation controls the exchange of matter between farms and the adjacent areas, which in turn establishes the nutrient supply that supports phytoplankton populations. The complexity of water circulation makes necessary the use of hydrodynamic models with detailed spatial resolution in carrying capacity estimations. This detailed spatial resolution also allows for the study of processes that depend on specific spatial arrangements, e.g., the most suitable location to place farms, which is crucial for marine spatial planning, and consequently for decision support systems. In the present study, a fully spatial physical-biogeochemical model has been combined with scenario building and optimization techniques as a proof of concept of the use of ecosystem modeling as an objective tool to inform marine spatial planning. The object of this exercise was to generate objective knowledge based on an ecosystem approach to establish new mussel aquaculture areas in a Norwegian fjord. Scenario building was used to determine the best location of a pump that can be used to bring nutrient-rich deep waters to the euphotic layer, increasing primary production, and consequently, carrying capacity for mussel cultivation. In addition, an optimization tool, parameter estimation (PEST), was applied to the optimal location and mussel standing stock biomass that maximize production, according to a preestablished carrying capacity criterion. Optimization tools allow us to make rational and transparent decisions to solve a well-defined question, decisions that are essential for policy makers. The outcomes of combining ecosystem models with scenario building and optimization facilitate planning based on an ecosystem approach, highlighting the capabilities of ecosystem modeling as a tool for marine spatial planning.

  20. A Modeling Study of Hydrodynamic Circulation in a Fjord of the Pacific Northwest

    SciTech Connect

    Wang, Taiping; Yang, Zhaoqing

    2012-10-01

    Increased eutrophication and degraded water quality in estuarine and coastal waters have been a worldwide environmental concern. While it is commonly accepted that anthropogenic impact plays a major role in many emerging water quality issues, natural conditions such as restricted water circulations controlled by geometry may also substantially contribute to unfavorable water quality in certain ecosystems. To elucidate the contributions from different factors, a hydrodynamic-water quality model that integrates both physical transport and pollutant loadings is particularly warranted. A preliminary modeling study using the Environmental Fluid Dynamic Code (EFDC) is conducted to investigate hydrodynamic circulation and low dissolved oxygen (DO) in Hood Canal, a representative fjord in the U.S. Pacific Northwest. Because the water quality modeling work is still ongoing, this paper focuses on the progress in hydrodynamic modeling component. The hydrodynamic model has been set up using the publicly available forcing data and was calibrated against field observations or NOAA predictions for tidal elevation, current, salinity and temperature. The calibrated model was also used to estimate physical transport timescales such as residence time in the estuary. The preliminary model results demonstrate that the EFDC Hood Canal model is capable of capturing the general circulation patterns in Hood Canal, including weak tidal current and strong vertical stratification. The long residence time (i.e., on the order of 100 days for the entire estuary) also indicates that restricted water circulation could contribute to low DO in the estuary and also makes the system especially susceptible to anthropogenic disturbance, such as excess nutrient input.

  1. Monitoring of a steep rockfall area experiencing fast displacements in Kåfjord, Northern Norway

    NASA Astrophysics Data System (ADS)

    Dreiås Majala, Gudrun; Harald Blikra, Lars; Skrede, Ingrid; Kristensen, Lene

    2016-04-01

    An unstable rockfall area in Kåfjord, Northern Norway, was recognized during periodic monitoring campaigns in July and early September 2015. The LiSALab ground based Interferometric Synthethic Aperture Radar (GB InSAR) from Ellegi were used. A relatively sharply defined steep area of 1200 m2 (6.000 - 12.000 m3) was documented to be in movement. Norwegian Water Resources and Energy Directorate (NVE) was at this point performing mitigation work in terms of an embarkment within the rockfall run-out area. The monitoring system was reinstalled and adjusted to perform continuous monitoring with an early-warning aim. The section for rockslide management in NVE was responsible for the monitoring and the warning to the municipality and Police. The displacements increased from about 1 mm/day in July to 3 cm/day in mid September. People were evalcuated due to increased velocities the 16th of September. The displacements continued to increase in several stages, and with a distinct accelleration the 2nd of October. The velocity peaked in a short window to more than 200 cm/day, and it ended with a partly frontal and sideway collapse of the unstable area. However, large parts of the area stabilized again, and the run-out lengths from the small rockfalls were limited. The GB InSAR system operated exceptionally well during the event, and were able to follow continuously the displacements during the accelleration stage until collapse as the processing time window was frequently adjusted to the changes in velocity. We were also able to follow inidividual rockfalls from the images - primarily as the rockfall impact points on the slope below showed up clearly on the radar images. The area continued to stabilize due to falling temperatures, and the mitigation work were finished during the fall. The displacements seem to be correlated to the increasing temperatures in late summer and precipitation events.

  2. Vertical mixing and internal wave energy fluxes in a sill fjord

    NASA Astrophysics Data System (ADS)

    Staalstrøm, André; Røed, Lars Petter

    2016-07-01

    We consider the distribution and level of local vertical mixing inside of the Drøbak Sill in the Oslofjord, Norway. The work is motivated by observations of long periods (∼years) of hypoxic or even anoxic conditions in the innermost basin, episodes attributed to weak vertical mixing. In line with earlier work on the subject we assume that the local vertical mixing level inside of the sill is predominantly determined by the loss of energy of propagating, tidally-induced internal waves whose source is the sill region. To investigate possible differences in vertical mixing we estimate the eddy diffusivity in the various basins based on model simulations and observations using three methods whereby the eddy diffusion coefficient is estimated. The model we use is an ultra high-resolution version of the three-dimensional, hydrostatic ocean model ROMS forced solely by barotropic tide well outside of the sill. To evaluate the sensitivity of the model results we perform sensitivity experiments in which the mesh size and various parameters and parameterizations are varied. We find indeed that the internal waves lose most of their energy before they reach the innermost basin, and hence set the scene for long periods of no deep water renewal. The sensitivity experiments reveal that it is important that the model's mesh size is small enough to resolve the dominant wavelengths of the topography. Moreover, we find that the strength of the turbulence production and hence the mixing depends on the initially chosen stratification. The method we use is generic and may be applied to any sill fjord.

  3. Alaska volcanoes guidebook for teachers

    USGS Publications Warehouse

    Adleman, Jennifer N.

    2011-01-01

    Alaska’s volcanoes, like its abundant glaciers, charismatic wildlife, and wild expanses inspire and ignite scientific curiosity and generate an ever-growing source of questions for students in Alaska and throughout the world. Alaska is home to more than 140 volcanoes, which have been active over the last 2 million years. About 90 of these volcanoes have been active within the last 10,000 years and more than 50 of these have been active since about 1700. The volcanoes in Alaska make up well over three-quarters of volcanoes in the United States that have erupted in the last 200 years. In fact, Alaska’s volcanoes erupt so frequently that it is almost guaranteed that an Alaskan will experience a volcanic eruption in his or her lifetime, and it is likely they will experience more than one. It is hard to imagine a better place for students to explore active volcanism and to understand volcanic hazards, phenomena, and global impacts. Previously developed teachers’ guidebooks with an emphasis on the volcanoes in Hawaii Volcanoes National Park (Mattox, 1994) and Mount Rainier National Park in the Cascade Range (Driedger and others, 2005) provide place-based resources and activities for use in other volcanic regions in the United States. Along the lines of this tradition, this guidebook serves to provide locally relevant and useful resources and activities for the exploration of numerous and truly unique volcanic landscapes in Alaska. This guidebook provides supplemental teaching materials to be used by Alaskan students who will be inspired to become educated and prepared for inevitable future volcanic activity in Alaska. The lessons and activities in this guidebook are meant to supplement and enhance existing science content already being taught in grade levels 6–12. Correlations with Alaska State Science Standards and Grade Level Expectations adopted by the Alaska State Department of Education and Early Development (2006) for grades six through eleven are listed at

  4. Teshekpuk Lake, Alaska

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This ASTER image of Teshekpuk Lake on Alaska's North Slope, within the National Petroleum Reserve, was acquired on August 15, 2000. It covers an area of 58.7 x 89.9 km, and is centered near 70.4 degrees north latitude, 153 degrees west longitude.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 58.7 by 89.9 kilometers (36.4 by 55.7 miles) Location: 70.4 degrees North latitude, 153 degrees West longitude Orientation: North at top Image Data: ASTER Bands 3, 2, and 1 Original Data Resolution: ASTER 30 meters (98.4 feet) Dates Acquired: August 15, 2000

  5. Evidence and implications of recent and projected climate change in Alaska's forest ecosystems

    USGS Publications Warehouse

    Wolken, Jane M.; Hollingsworth, Teresa N.; Rupp, T. Scott; Chapin, Stuart III; Trainor, Sarah F.; Barrett, Tara M.; Sullivan, Patrick F.; McGuire, A. David; Euskirchen, Eugénie S.; Hennon, Paul E.; Beever, Erik A.; Conn, Jeff S.; Crone, Lisa K.; D'Amore, David V.; Fresco, Nancy; Hanley, Thomas A.; Kielland, Knut; Kruse, James J.; Patterson, Trista; Schuur, Edward A.G.; Verbyla, David L.; Yarie, John

    2011-01-01

    The structure and function of Alaska's forests have changed significantly in response to a changing climate, including alterations in species composition and climate feedbacks (e.g., carbon, radiation budgets) that have important regional societal consequences and human feedbacks to forest ecosystems. In this paper we present the first comprehensive synthesis of climate-change impacts on all forested ecosystems of Alaska, highlighting changes in the most critical biophysical factors of each region. We developed a conceptual framework describing climate drivers, biophysical factors and types of change to illustrate how the biophysical and social subsystems of Alaskan forests interact and respond directly and indirectly to a changing climate. We then identify the regional and global implications to the climate system and associated socio-economic impacts, as presented in the current literature. Projections of temperature and precipitation suggest wildfire will continue to be the dominant biophysical factor in the Interior-boreal forest, leading to shifts from conifer- to deciduous-dominated forests. Based on existing research, projected increases in temperature in the Southcentral- and Kenai-boreal forests will likely increase the frequency and severity of insect outbreaks and associated wildfires, and increase the probability of establishment by invasive plant species. In the Coastal-temperate forest region snow and ice is regarded as the dominant biophysical factor. With continued warming, hydrologic changes related to more rapidly melting glaciers and rising elevation of the winter snowline will alter discharge in many rivers, which will have important consequences for terrestrial and marine ecosystem productivity. These climate-related changes will affect plant species distribution and wildlife habitat, which have regional societal consequences, and trace-gas emissions and radiation budgets, which are globally important. Our conceptual framework facilitates

  6. Retarded deglaciation of north-Spitsbergen fjords during the last glacial - an example of bathymetric controls on the dynamics of retreating glaciers

    NASA Astrophysics Data System (ADS)

    Forwick, M.; Vorren, T. O.; Hass, H.; Vogt, C. M.

    2012-12-01

    North and west Spitsbergen fjords acted as pathways for fast-flowing ice streams during the last glacial (e.g. Ottesen et al., 2005). The deglaciation of west Spitsbergen fjords occurred stepwise and the ice retreat terminated around 11,200 cal. years BP (calendar years before the present; e.g. Forwick & Vorren, 2009, 2011, and references therein; Baeten et al., 2010). However, the deglaciation dynamics and chronology of north Spitsbergen fjords still remain poorly understood. We present swath-bathymetry, high-resolution seismic data and two sediment cores from the approx. 110 km long, N-S oriented Wijdefjorden-Austfjorden fjord system, the largest fjord system on northern Spitsbergen. The data indicate that - as in the fjords on west Spitsbergen - multiple halts and/or readvances interrupted the retreat of the ice front during the final phase of the last glacial. However, even though the study area and several west Spitsbergen fjords are fed by the same glacier source (the ice field Lomonosovfonna), the final deglaciation of Wijdefjorden-Austfjorden took place after 9300 cal. years BP, i.e. at least approx. 2000 years later than in the west. We assume that the retarded deglaciation in the north is mainly related to the fjord bathymetry, i.e. a more than 35 km wide and up to 60 m high area in the central parts of the study area (approx. 45 km beyond the present fjord head) that acted as pinning point for the grounded glacier. Multiple, relatively large and partly stacked moraine ridges and sediment wedges are suggested to reflected that the ice front retreated slowly across this shallow area and that repeated readvances interrupted this retreat. The absence of larger sediment wedges in the deeper parts between the shallow area and the fjord head may indicate that the final retreat occurred relatively rapid. References: Baeten, N.J., Forwick, M., Vogt, C. & Vorren, T.O., 2010. Late Weichselian and Holocene sedimentary environments and glacial activity in

  7. Information needs for habitat protection: Marbled murrelet habitat identification. Restoration project 93051b. Exxon Valdez oil spill restoration project final report

    SciTech Connect

    Kuletz, K.J.; Marks, D.K.; Naslund, N.L.; Goodson, N.G.; Cody, M.B.

    1994-12-01

    To define murrelet nesting habitat in southcentral Alaska, we surveyed inland activity of murrelets and measured habitat features between 1991 and 1993, in Prince William Sound, Kenai Fjords National Park and Afognak Island, Alaska (N=262 sites). Using all study areas, we developed statistical models that explain variation in murrelet activity levels and predict the occurrence of behaviors indicative of nesting, based on temporal, geographic, topographic, weather and habitat variables. The multiple regression analyses explained 52 percent of the variation in murrelet activity level. Stepwise logistic regression was used to identify variables that could predict the occurrence of nesting behaviors. The best model included survey method (from a boat, shore or inland), location relative to the head of a bay, tree diameter and number of potential nesting platforms on trees. Overall, the features indicative of murrelet nesting habitat included low elevation locations near the heads of bays, with extensive forest cover of large old-growth trees.

  8. Simultaneous observations of ice motion, calving and seismicity on the Yahtse Glacier, Alaska. (Invited)

    NASA Astrophysics Data System (ADS)

    Larsen, C. F.; Bartholomaus, T. C.; O'Neel, S.; West, M. E.

    2010-12-01

    We observe ice motion, calving and seismicity simultaneously and with high-resolution on an advancing tidewater glacier in Icy Bay, Alaska. Icy Bay’s tidewater glaciers dominate regional glacier-generated seismicity in Alaska. Yahtse emanates from the St. Elias Range near the Bering-Bagley-Seward-Malaspina Icefield system, the most extensive glacier cover outside the polar regions. Rapid rates of change and fast flow (>16 m/d near the terminus) at Yahtse Glacier provide a direct analog to the disintegrating outlet systems in Greenland. Our field experiment co-locates GPS and seismometers on the surface of the glacier, with a greater network of bedrock seismometers surrounding the glacier. Time-lapse photogrammetry, fjord wave height sensors, and optical survey methods monitor iceberg calving and ice velocity near the terminus. This suite of geophysical instrumentation enables us to characterize glacier motion and geometry changes while concurrently listening for seismic energy release. We are performing a close examination of calving as a seismic source, and the associated mechanisms of energy transfer to seismic waves. Detailed observations of ice motion (GPS and optical surveying), glacier geometry and iceberg calving (direct observations and timelapse photogrammetry) have been made in concert with a passive seismic network. Combined, the observations form the basis of a rigorous analysis exploring the relationship between glacier-generated seismic events and motion, glacier-fiord interactions, calving and hydraulics. Our work is designed to demonstrate the applicability and utility of seismology to study the impact of climate forcing on calving glaciers.

  9. Holocene primary productivity and the atmosphere/ocean linkage in the Gulf of Alaska

    NASA Astrophysics Data System (ADS)

    Addison, J. A.; Finney, B.; Anderson, L.; Barron, J. A.; Hayes, S. M.; Sliwinski, M.; Mix, A. C.

    2015-12-01

    Recent work in the temperate fjords of the Gulf of Alaska, located in the subarctic northeast Pacific Ocean, has demonstrated a positive link between modern atmosphere/ocean dynamics and accumulation of biogenic sediments during the last 100 years, where intensified Aleutian Low atmospheric pressure cell regimes correspond to peaks in export primary productivity (Addison et al., 2013). Here, this work is extended by examining the last 7500 years of biogenic sedimentation from marine sediment core EW0408-33JC (57.16°N, 135.36°W, 144 m water depth), which is constrained by 17 age-control points spaced every ~500 years. We use bromine (Br) intensities measured by core-scanning XRF with a 2-mm sampling resolution as a geochemical proxy for past primary productivity. These Br intensities are calibrated to organic Br concentrations using a combination of quantitative WD-XRF methods and synchrotron-radiation Br speciation studies, with cross-verification provided by low-resolution analyses of other productivity proxies, including biogenic silica (opal), total organic carbon (TOC), and organic matter δ13C ratios. Our findings indicate distinct centennial-to-millennial changes, with positive productivity excursions between 7500-7000, 6500-6000, 5000-3500, 2500-1500, and 1000-500 INTCAL13 yr BP. We compare the timing of these excursions against a compilation of marine and terrestrial paleoclimate records sensitive to forcing by the Aleutian Low to determine if the positive relationship between atmosphere/ocean dynamics and marine primary productivity has remained consistent over the last 7500 years. Other potential forcing mechanisms (e.g., solar insolation, irradiance) are also considered. Reference: Addison, J.A., Finney, B., Jaeger, J., Stoner, J., Norris, R., & Hangsterfer, A., 2013, Integrating satellite observations and modern climate measurements with the recent sedimentary record: an example from Southeast Alaska. JGR-Oceans, v. 118, 18 pgs.

  10. Tuberculosis among Children in Alaska.

    ERIC Educational Resources Information Center

    Gessner, Bradford D.

    1997-01-01

    The incidence of tuberculosis among Alaskan children under 15 was more than twice the national rate, with Alaska Native children showing a much higher incidence. Children with household exposure to adults with active tuberculosis had a high risk of infection. About 22 percent of pediatric tuberculosis cases were identified through school…

  11. Tularemia in Alaska, 1938 - 2010

    PubMed Central

    2011-01-01

    Tularemia is a serious, potentially life threatening zoonotic disease. The causative agent, Francisella tularensis, is ubiquitous in the Northern hemisphere, including Alaska, where it was first isolated from a rabbit tick (Haemophysalis leporis-palustris) in 1938. Since then, F. tularensis has been isolated from wildlife and humans throughout the state. Serologic surveys have found measurable antibodies with prevalence ranging from < 1% to 50% and 4% to 18% for selected populations of wildlife species and humans, respectively. We reviewed and summarized known literature on tularemia surveillance in Alaska and summarized the epidemiological information on human cases reported to public health officials. Additionally, available F. tularensis isolates from Alaska were analyzed using canonical SNPs and a multi-locus variable-number tandem repeats (VNTR) analysis (MLVA) system. The results show that both F. t. tularensis and F. t. holarctica are present in Alaska and that subtype A.I, the most virulent type, is responsible for most recently reported human clinical cases in the state. PMID:22099502

  12. A Title I Refinement: Alaska.

    ERIC Educational Resources Information Center

    Hazelton, Alexander E.; And Others

    Through joint planning with a number of school districts and the Region X Title I Technical Assistance Center, and with the help of a Title I Refinement grant, Alaska has developed a system of data storage and retrieval using microcomputers that assists small school districts in the evaluation and reporting of their Title I programs. Although this…

  13. Adventures in the Alaska Economy.

    ERIC Educational Resources Information Center

    Jackstadt, Steve; Huskey, Lee

    This publication was developed to increase students' understanding of basic economic concepts and the historical development of Alaska's economy. Comics depict major historical events as they occurred, but specific characters are fictionalized. Each of nine episodes is accompanied by several pages of explanatory text, which enlarges on the episode…

  14. Tularemia in Alaska, 1938 - 2010.

    PubMed

    Hansen, Cristina M; Vogler, Amy J; Keim, Paul; Wagner, David M; Hueffer, Karsten

    2011-01-01

    Tularemia is a serious, potentially life threatening zoonotic disease. The causative agent, Francisella tularensis, is ubiquitous in the Northern hemisphere, including Alaska, where it was first isolated from a rabbit tick (Haemophysalis leporis-palustris) in 1938. Since then, F. tularensis has been isolated from wildlife and humans throughout the state. Serologic surveys have found measurable antibodies with prevalence ranging from < 1% to 50% and 4% to 18% for selected populations of wildlife species and humans, respectively. We reviewed and summarized known literature on tularemia surveillance in Alaska and summarized the epidemiological information on human cases reported to public health officials. Additionally, available F. tularensis isolates from Alaska were analyzed using canonical SNPs and a multi-locus variable-number tandem repeats (VNTR) analysis (MLVA) system. The results show that both F. t. tularensis and F. t. holarctica are present in Alaska and that subtype A.I, the most virulent type, is responsible for most recently reported human clinical cases in the state. PMID:22099502

  15. Negative effects of blue mussel ( Mytilus edulis) presence in eelgrass ( Zostera marina) beds in Flensborg fjord, Denmark

    NASA Astrophysics Data System (ADS)

    Vinther, Hanne Fogh; Laursen, Jens Sund; Holmer, Marianne

    2008-03-01

    The effect of blue mussel ( Mytilus edulis) presence in eelgrass ( Zostera marina) beds was studied from June 2004 to July 2005 in Flensborg fjord, Denmark. The field experiments were conducted at two stations, one with only Z. marina (Eelgrass station) present and one where M. edulis were present in the Z. marina beds (Mixed station). Zostera marina parameters were measured (growth of leaves, shoot density, leaf length, and nutrient content) in combination with epiphyte cover and sediment parameters (sulphate reduction rates, sediment nutrient fluxes, organic content, C, N and P content) to examine possible positive and negative effects of the mussels on eelgrass performance. The fluxes of ammonium from the sediments were stimulated at all sampling dates at the Mixed station, and possibly stimulated epiphyte growth at this station. Further 15N signals in epiphytes from the Mixed station suggested that excretion products from the mussels were important nitrogen sources at this station. Sulphate reduction rates were enhanced at the Mixed station and also sediment sulphide concentrations increased under mussel influence, which may have resulted in sulphide toxicity and decreased growth of Z. marina at this station. The study indicates that for Z. marina beds in Flensborg Fjord the effects of M. edulis in seagrass beds are primarily negative, and raises the question whether this leads to negative effects on the stability and expansion of Z. marina beds.

  16. Wintertime water dynamics and moonlight disruption of the acoustic backscatter diurnal signal in an ice-covered Northeast Greenland fjord

    NASA Astrophysics Data System (ADS)

    Petrusevich, Vladislav; Dmitrenko, Igor A.; Kirillov, Sergey A.; Rysgaard, Søren; Falk-Petersen, Stig; Barber, David G.; Boone, Wieter; Ehn, Jens K.

    2016-07-01

    Six and a half month records from three ice-tethered Acoustic Doppler Current Profilers deployed in October 2013 in Young Sound fjord in Northeast Greenland are used to analyze the acoustic backscatter signal. The acoustic data suggest a systematic diel vertical migration (DVM) of scatters below the land-fast ice during polar night. The scatters were likely composed of zooplankton. The acoustic signal pattern typical to DVM persisted in Young Sound throughout the entire winter including the period of civil polar night. However, polynya-enhanced estuarine-like cell circulation that occurred during winter disrupted the DVM signal favoring zooplankton to occupy the near-surface water layer. This suggests that zooplankton avoided spending additional energy crossing the interface with a relatively strong velocity gradient comprised by fjord inflow in the intermediate layer and outflow in the subsurface layer. Instead, the zooplankton tended to remain in the upper 40 m layer where relatively warmer water temperatures associated with upward heat flux during enhanced estuarine-like circulation could be energetically favorable. Furthermore, our data show moonlight disruption of DVM in the subsurface layer and weaker intensity of vertical migration beneath snow covered land-fast ice during polar night. Finally, by using existing models for lunar illuminance and light transmission through sea ice and snow cover, we estimated under ice illuminance and compared it with known light sensitivity of Arctic zooplankton species.

  17. Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez

    NASA Astrophysics Data System (ADS)

    Parsons, Tom; Geist, Eric L.; Ryan, Holly F.; Lee, Homa J.; Haeussler, Peter J.; Lynett, Patrick; Hart, Patrick E.; Sliter, Ray; Roland, Emily

    2014-11-01

    Like many subduction zone earthquakes, the deadliest aspects of the 1964 M = 9.2 Alaska earthquake were the tsunamis it caused. The worst of these were generated by local submarine landslides induced by the earthquake. These caused high runups, engulfing several coastal towns in Prince William Sound. In this paper, we study one of these cases in detail, the Port Valdez submarine landslide and tsunami. We combine eyewitness reports, preserved film, and careful posttsunami surveys with new geophysical data to inform numerical models for landslide tsunami generation. We review the series of events as recorded at Valdez old town and then determine the corresponding subsurface events that led to the tsunami. We build digital elevation models of part of the pretsunami and posttsunami fjord-head delta. Comparing them reveals a ~1500 m long region that receded 150 m to the east, which we interpret as the primary delta landslide source. Multibeam imagery and high-resolution seismic reflection data identify a ~400 m wide chute with hummocky deposits at its terminus, which may define the primary slide path. Using these elements we run hydrodynamic models of the landslide-driven tsunamis that match observations of current direction, maximum inundation, and wave height at Valdez old town. We speculate that failure conditions at the delta front may have been influenced by manmade changes in drainage patterns as well as the fast retreat of Valdez and other glaciers during the past century.

  18. Meteorological aspects of benzene transport, dispersion and personal exposure in Valdez, Alaska

    SciTech Connect

    Murray, D.R.; Ball, R.J.

    1994-12-31

    The Valdez Air Health Study (VAHS) was conducted in Valdez, Alaska to determine the personal exposure of the residential population of Valdez to certain volatile organic compounds (VOCs). The VAHS used the EPA`s Total Exposure Assessment Methodology (TEAM) with continuous meteorology, air quality and intense tracer measurements to monitor personal and indoor/outdoor concentrations of VOCs in the community. The Valdez fjord is the site of the Alyeska Marine Terminal, the largest crude oil loading terminal in the United States, with a maximum capacity of 2.2 million barrels per day. The Alyeska Marine Terminal is the transfer point for Prudhoe Bay crude oil from the pipeline to marine tankers. During 1990, the terminal and marine tankers were estimated to emit approximately 450 metric tonnes/year of benzene to the air at an average throughput of 1.8 million barrels/day while benzene emissions from other sources in the basin were estimated to be approximately 3 tonnes/year.

  19. Glaciological and marine geological controls on terminus dynamics of Hubbard Glacier, southeast Alaska

    USGS Publications Warehouse

    Stearns, Leigh A.; Hamilton, Gordon S.; van der Veen, C. J.; Finnegan, D. C.; O'Neel, Shad; Scheick, J. B.; Lawson, D. E.

    2015-01-01

    Hubbard Glacier, located in southeast Alaska, is the world's largest non-polar tidewater glacier. It has been steadily advancing since it was first mapped in 1895; occasionally, the advance creates an ice or sediment dam that blocks a tributary fjord (Russell Fiord). The sustained advance raises the probability of long-term closure in the near-future, which will strongly impact the ecosystem of Russell Fiord and the nearby community of Yakutat. Here, we examine a 43-year record of flow speeds and terminus position to understand the large-scale dynamics of Hubbard Glacier. Our long-term record shows that the rate of terminus advance has increased slightly since 1895, with the exception of a slowed advance between approximately 1972 and 1984. The short-lived closure events in 1986 and 2002 were not initiated by perturbations in ice velocity or environmental forcings, but were likely due to fluctuations in sedimentation patterns at the terminus. This study points to the significance of a coupled system where short-term velocity fluctuations and morainal shoal development control tidewater glacier terminus position.

  20. Effects of the earthquake of March 27, 1964, on air and water transport, communications, and utilities systems in south-central Alaska: Chapter B in The Alaska earthquake, March 27, 1964: effects on transportation, communications, and utilities

    USGS Publications Warehouse

    Eckel, Edwin B.

    1967-01-01

    The earthquake of March 27, 1964, wrecked or severely hampered all forms of transportation, all utilities, and all communications systems over a very large part of south-central Alaska. Effects on air transportation were minor as compared to those on the water, highway, and railroad transport systems. A few planes were damaged or wrecked by seismic vibration or by flooding. Numerous airport facilities were damaged by vibration or by secondary effects of the earthquake, notably seismic sea and landslide-generated waves, tectonic subsidence, and compaction. Nearly all air facilities were partly or wholly operational within a few hours after the earthquake. The earthquake inflicted enormous damage on the shipping industry, which is indispensable to a State that imports fully 90 percent of its requirements—mostly by water—and whose largest single industry is fishing. Except for those of Anchorage, all port facilities in the earthquake-affected area were destroyed or made inoperable by submarine slides, waves, tectonic uplift, and fire. No large vessels were lost, but more than 200 smaller ones (mostly crab or salmon boats) were lost or severely damaged. Navigation aids were destroyed, and hitherto well-known waterways were greatly altered by uplift or subsidence. All these effects wrought far-reaching changes in the shipping economy of Alaska, many of them to its betterment. Virtually all utilities and communications in south-central Alaska were damaged or wrecked by the earthquake, but temporary repairs were effected in remarkably short times. Communications systems were silenced almost everywhere by loss of power or by downed lines; their place was quickly taken by a patchwork of self-powered radio transmitters. A complex power-generating system that served much of the stricken area from steam, diesel, and hydrogenerating plants was disrupted in many places by vibration damage to equipment and by broken transmission lines. Landslides in Anchorage broke gas

  1. Air temperature and humidity diversity in the Hornsund fjord area (Spitsbergen) in the period 1 July 2014 - 30 June 2015

    NASA Astrophysics Data System (ADS)

    Przybylak, Rajmund; Araźny, Andrzej; Wyszyński, Przemysław; Budzik, Tomasz; Wawrzyniak, Tomasz

    2016-04-01

    The article presents preliminary results of studies into the spatial diversity of air temperature and relative humidity (overground layer, 2 m a.g.l.) in the area of the Hornsund fjord (S Spitsbergen, approx. 77°N), based on data collected between 1 July 2014 and 30 June 2015. The Hornsund fjord runs latitudinal along approx. 40 km and its average width is about 10 km. Numerous glaciers flow into the fjord and the mountain ridges around it often exceed 700 m a.s.l. Data series obtained from 11 sites equipped with automatic weather stations (Vaisala, Campbell, Davis) or HOBO temperature and humidity sensors were used. Two sites (Hornsund HOR and the Hans Glacier HG4) have been operating for years, whereas 9 new ones (Bogstranda BOG, Fugleberget FUG, Gnålodden GNA, Gåshamnoyra GAS, Hyttevika HYT, Lisbetdalen LIS, Ostrogradskijfjella OST, Treskelodden TRE and Wilczekodden WIL) were established within the Polish-Norwegian AWAKE-2 project. Three of the sites (BOG, GAS and OST) were damaged by polar bears, hence their measurement series are shorter. A substantial spatial diversity was found in the air temperature and relative humidity in the area, mostly influenced by elevation, type of surface and distance from the Greenland Sea's open water. During the year (July 2014 - June 2015), the areas of HYT (-1.1°C) and WIL (-1.9°C) were the warmest. Both sites are located on the west coast of the fjord. The HYT demonstrates the most favourable temperature conditions, being orographically sheltered from the east and its cold and dry air masses. The coldest sites were the mountain-top site of FUG (-5.9°C) and the glacier-located HG4 (-4.3°C). The low temperature at FUG resulted from its elevation (568 m a.s.l.), whereas at HG4 (184 m a.s.l) the glaciated surface also added up to the result. In the analysed period, the annual course of air temperature in the area had a clear minimum in February, when the lowest mean monthly values ranged from -9.4°C at HYT to -15.1°C at

  2. Fjord circulation and hydrographic structure associated with a rapidly-retreating glacier in the Patagonian Ice Fields

    NASA Astrophysics Data System (ADS)

    Moffat, C. F.

    2013-12-01

    Understanding the structure of buoyant plumes originating from melting glaciers and their interaction with the hydrographic structure and circulation of the surrounding ocean is key to elucidating the role of the ocean in modulating freshwater loss from the continents and to appropriately estimate present and future sea-level rise. Here, hydrographic and current velocity surveys are used to study the freshwater outflow in a fjord adjacent to Jorge Montt, an until recently rapidly (1 km/year) retreating glacier in the southern Patagonian Ice Fields. Surveys were conducted in the Summer of 2010 to 2012, Winter of 2011 and Fall 2012 to provide constraints on seasonal-scale changes. Montt fjord is approximately 20 km long, and is composed of a deep, proximal (to the ice) sub-basin of 350 m maximum depth and a shallower, distal sub-basin of around 100 m depth. Exchange with the 120-km long Baker Channel, the main conduit of exchange for the fjord with the South Eastern Pacific is severely constrained by a v-shaped, 45-m deep sill. During Summer, the freshwater outflow from the glacier mixes with the deep oceanic water found in the fjord to form a buoyant plume. This plume splits into a branch that reaches the surface and forms a relatively thick (10-20 m) brackish layer with salinities of 5 or less, and at least one subsurface branch that forms a horizontally coherent lateral intrusion found everywhere in the deep sub-basin. Results from using a thermodynamical melting model in combination with a linear mixing model suggest that the meltwater in the plume is dominated by subsurface runoff (10 %) with a smaller proportion of submarine melt (1-3 %). The fraction of subsurface runoff is higher in the top 100 m and it increases monotonically towards the surface, while subsurface melting also has a subsurface concentration maximum between 100 and 150 m. Velocity measurements show flow away from the glacier at the surface layer (top 10-20 m) and also at mid-depth, below the

  3. Dynamic response to strike-slip tectonic control on the deposition and evolution of the Baranof Fan, Gulf of Alaska

    USGS Publications Warehouse

    Walton, Maureen A. L.; Gulick, Sean P. S.; Reece, Robert S.; Barth, Ginger A.; Christeson, Gail L.; VanAvendonk, Harm J.

    2014-01-01

    The Baranof Fan is one of three large deep-sea fans in the Gulf of Alaska, and is a key component in understanding large-scale erosion and sedimentation patterns for southeast Alaska and western Canada. We integrate new and existing seismic reflection profiles to provide new constraints on the Baranof Fan area, geometry, volume, and channel development. We estimate the fan’s area and total sediment volume to be ∼323,000 km2 and ∼301,000 km3, respectively, making it among the largest deep-sea fans in the world. We show that the Baranof Fan consists of channel-levee deposits from at least three distinct aggradational channel systems: the currently active Horizon and Mukluk channels, and the waning system we call the Baranof channel. The oldest sedimentary deposits are in the northern fan, and the youngest deposits at the fan’s southern extent; in addition, the channels seem to avulse southward consistently through time. We suggest that Baranof Fan sediment is sourced from the Coast Mountains in southeastern Alaska, transported offshore most recently via fjord to glacial sea valley conduits. Because of the translation of the Pacific plate northwest past sediment sources on the North American plate along the Queen Charlotte strike-slip fault, we suggest that new channel formation, channel beheadings, and southward-migrating channel avulsions have been influenced by regional tectonics. Using a simplified tectonic reconstruction assuming a constant Pacific plate motion of 4.4 cm/yr, we estimate that Baranof Fan deposition initiated ca. 7 Ma.

  4. A 100-year record of changes in water renewal rate in Sermilik fjord and its influence on calving of Helheim glacier, southeast Greenland

    NASA Astrophysics Data System (ADS)

    Andresen, Camilla S.; Schmidt, Sabine; Seidenkrantz, Marit-Solveig; Straneo, Fiammetta; Grycel, Aleksandra; Hass, Christian H.; Henrik Kjær, Kurt; Nørgaard-Pedersen, Niels; Dyke, Laurence M.; Olsen, Jesper; Kuijpers, Antoon

    2014-08-01

    Here we present a 100 year long proxy record for the renewal rate of the subsurface ocean waters in Sermilik Fjord at the edge of Helheim Glacier, based on investigations of two sediment cores (ER11-24 and ER11-25) obtained from the head of the fjord. By calculating the mean sortable silt (SSbar) in current-sorted melt water plume sediments we find that episodes of increased water renewal rates lasting 3-5 years coincide with a positive North Atlantic Oscillation (NAO) index. This is not surprising as low pressure systems and northeasterly storms are observed more frequently along the east coast of Greenland during positive NAO years as a result of the northward shift in the North Atlantic storm track. Previous studies of sediment cores obtained from the mid-region of the fjord showed that Helheim Glacier destabilization coincides with a negative NAO index. Therefore we conclude that inter-annual variability in storm-induced flushing of Sermilik Fjord and thus the water renewal rate towards the glacier margin is not the controlling factor for inter-annual variability in Helheim Glacier destabilization. Such knowledge may have implications on predictive model studies of ice-ocean interactions and glacier behavior.

  5. Morphodynamics and Sedimentology of a Falling Stage Sandy Fjord Delta, Goose River, Labrador

    NASA Astrophysics Data System (ADS)

    Slingerland, R.; Edmonds, D. A.; Parsons, D. R.; Best, J. L.; Royce, J.; Burpee, A.; Cederberg, J.; Caldwell, R.; Nijhuis, A.; McGuffin, A.

    2012-12-01

    Sediment size and degree of cohesion are thought to exert a strong control on the morphodynamic processes, planform shape and clinoform stratigraphy of deltas. To test model predictions concerning these two parameters, we present a morphometric and stratigraphic analysis of a sandy delta formed where the Goose River flows into Goose Bay at the western end of Lake Melville, Labrador. Goose River delta sediments consist of arkosic, heavy-mineral-rich sand (D50 = 225 to 600 microns) with very little silt and clay, placing this delta at the coarser-grained, non-cohesive end of the spectrum. The delta started to form approx. 7000 years ago as the Laurentide ice sheet retreated and post-glacial rebound created a relative base level fall of approximately 4 mm/yr. The current tidal range in Goose Bay averages 0.5 m, and the average wave height is negligible. Results from our 2012 field season show that the delta planform consists of two moribund lobes at elevations of ~ 5 m and ~ 2 m and a presently active delta at sea level. Aerial photography from 1951 to 2012 show there has been surprisingly little progradation despite active channel change at the six-month timescale and an assumed base level fall of 244 mm during that period. A topographic section along a dipline consists of three treads and two clinoform risers. The bottomset tread is a virtually featureless fjord bottom at ~35 m from which a first clinoform rises to a second tread at ~-15 m. The second tread is a sandy platform onto which an upper clinoform downlaps. This upper sandy clinoform ranges in dip from 9 to 17 dg. and passes into the topset at an elevation of ~ -1 m. The topset consists of braid-like trapezoidal unit bars that in GPR show little evidence of wave, alongshore current, or ice reworking, even though they are submerged at higher high tides. The planform, bar geometries and facies, and clinoform dips and dip-directions are remarkably consistent with model predictions from Delft3d.

  6. Shallow Sub-Permafrost Groundwater Systems In A Buried Fjord: Taylor Valley, Antarctica

    NASA Astrophysics Data System (ADS)

    Foley, N.; Tulaczyk, S. M.; Auken, E.; Mikucki, J.

    2014-12-01

    The McMurdo Dry Valleys (MDV), Antarctica, represent a unique geologic setting where permanent lakes, ephemeral streams, and subglacial waters influence surface hydrology in a cold polar desert. Past research suggested that the MDV are underlain by several hundreds of meters of permafrost. Here, we present data collected from an Airborne EM (AEM) resistivity sensor flown over the MDV during the 2011-12 austral summer. A focus of our survey was over the Taylor Glacier where saline, iron-rich subglacial fluid releases at the glacier snout at a feature known as Blood Falls, and over Taylor Valley, where a series of isolated lakes lie between Taylor Glacier and the Ross Sea. Our data show that in Taylor Valley there are extensive areas of low resistivity, interpreted as hypersaline brines, beneath a relatively thin layer of high resistivity material, interpreted as dry- or ice-cemented permafrost. These hypersaline brines remain liquid at temperatures well below 0°C due to their salinity. They appear to be contained within the sedimentary fill deposited in Taylor Valley when it was still a fjord. This brine system continues up valley and has a subglacial extension beneath Taylor Glacier, where it may provide the source that feeds Blood Falls. By categorizing the resistivity measurements according to surficial land cover, we are able to distinguish between ice, permafrost, lake water, and seawater based on characteristic resistivity distributions. Furthermore, this technique shows that areas of surface permafrost become increasingly conductive (brine-filled) with depth, whereas the large lakes exhibit taliks that extend through the entire thickness of the permafrost. The subsurface brines represent a large, unstudied and potentially connected hydrogeologic system, in which subsurface flows may help transfer water and nutrients between lakes in the MDV and into the Ross Sea. Such a system is a potential habitat for extremophile life, similar to that already detected in

  7. Minority Women's Health: American Indians/Alaska Natives

    MedlinePlus

    ... Health > American Indians/Alaska Natives Minority Women's Health American Indians/Alaska Natives Related information How to Talk to ... disease. Return to top Health conditions common in American Indian and Alaska Native women Accidents Alcoholism and drug ...

  8. Slope stability, triggering factors and threshold conditions. Study of debris flow activity in the Reyðarfjörður fjord, eastern Iceland.

    NASA Astrophysics Data System (ADS)

    Margeirsson, Guðbjörn; Sæmundsson, Þorsteinn; Norðdahl, Hreggviður

    2016-04-01

    Precipitation is one of the main triggering factor for debris flow activity in Eastern Iceland, but the amount needed, duration and the rainfall and its intensity to trigger the flow (e.g. the threshold condition) can vary considerably between areas. There are a few factors that have to be taken into account to determine the threshold condition and slope stability between areas, such as the slope angle and aspect, type and thickness of loose material, vegetation cover and gully distribution. Weather factors such as air and soil temperature, wind speed and wind direction is also crucial. The study area is located in the Reyðarfjörður fjord, one of the longest fjords on the east coast of Iceland. It is a 30 km long glacially eroded fjord, cut into the Tertiary bedrock. The bedrock is mostly made up of jointed basaltic lava flows, individual flows can vary in thickness from 2-30 m and usually separated by lithified sedimentary horizons often red in color. The slopes of the fjord are steep up to 900 m high, often consisting of nearly vertical cliffs, 60°-90°, in the upper parts of the slopes. The lower parts are covered with various glaciogenic landforms and consist of sediments and talus material. Several small hanging valleys and numerous small gullies and streams occur along the both sides of the fjord. The debris flow activity in the Reyðafjörður fjord is mostly constrained to the gullies and streams. Some activity has also been observed on the slopes between the gullies, but such activity is usually connected to extreme conditions, during or following heavy rain storms or a rainfall, especially of long duration. The aim of the study is to map the distribution of loose slope sediments in two areas inside the fjord, collect data about the known debris flow history, analyze various weather patterns which have contributed to these debris flows and understand how variables between the slopes react differently to different factors.

  9. Land-ocean gradient in haline stratification and its effects on plankton dynamics and trophic carbon fluxes in Chilean Patagonian fjords (47-50°S)

    NASA Astrophysics Data System (ADS)

    González, H. E.; Castro, L. R.; Daneri, G.; Iriarte, J. L.; Silva, N.; Tapia, F.; Teca, E.; Vargas, C. A.

    2013-12-01

    Patagonian fjord systems, and in particular the fjords and channels associated with the Baker/Pascua Rivers, are currently under conspicuous natural and anthropogenic perturbations. These systems display very high variability, where limnetic and oceanic features overlap generating strong vertical and horizontal physicochemical gradients. The CIMAR 14-Fiordos cruise was conducted in the Chilean fjords located between 47° and 50°S during the spring (October-November) of 2008. The main objectives were to study vertical and horizontal gradients in physical, chemical and biological characteristics of the water column, and to assess plankton dynamics and trophic carbon fluxes in the fjords and channels of central-south Patagonia. The water column was strongly stratified, with a pycnocline at ca. 20 m depth separating a surface layer of silicic acid-rich freshwater discharged by rivers, from the underlying nitrate- and orthophosphate-rich Subantarctic waters. The outflows from the Baker and Pascua Rivers, which range annually between 500 and 1500 m3 s-1, generate the strong land-ocean gradient in salinity (1-32 psu) and inorganic nutrient concentrations (2-8 and 2-24 μM in nitrate and silicic-acid, respectively) we observed along the Baker Fjord. The POC:chl-a ratio fluctuated from 1087 near the fjord’s head to 175 at its oceanic end in the Penas Gulf. This change was mainly due to an increase in diatom dominance and a concurrent decrease in allochthonous POC towards the ocean. Depth-integrated net primary production (NPP) and bacterial secondary production (BSP) fluctuated between 49 and 1215 and 36 and 150 mg C m-2 d-1, respectively, with higher rates in oceanic waters. At a time series station located close to the Baker River mouth, the average NPP was lower (average 360 mg C m-2 d-1) than at more oceanic stations (average 1063 mg C m-2 d-1), and numerically dominated (45%) by the picoplankton (<2 μm) and nanoplankton (2-20 μm) size fractions. The high average

  10. Glacio-tectonic thrust and deformation structures in the Vejle Fjord, Denmark revealed by high-resolution subbottom-profile data

    NASA Astrophysics Data System (ADS)

    Andresen, Katrine Juul; Boldreel, Lars Ole; Bak Wahlgreen, Katrine; Seidenkrantz, Marit-Solveig; Røy, Hans; Nørmark, Egon; Brandbyge Ernstsen, Verner

    2016-04-01

    Surface geomorphological features and partial cliff exposures up till now represent the predominant source of information of glaciation related deformation in Denmark. In this study we apply high-resolution marine reflection seismic data from the Vejle Fjord area, supported by gravity and Rumohr coring, to document intense glacio-tectonic deformation in the shallow subsurface of Denmark. The subbottom profiler seismic data have a peak frequency around 13 kHz and a vertical resolution in the order of 10-20 cm. The data reveal several variations of glacio-tectonic deformation structures, primarily observed near the edges of the fjord where coarse-grained and sandy deposits are present. These sediments allows for an exceptionally good and high-resolution imaging of the marine shallow subsurface. Within the central regions of the fjord, widespread shallow gas accumulations probably generated from biodegradation of post glacial organic-rich fine-grained marine gytja and clay deposits, effectively blank and absorb the seismic signal. This leads to a very poor imaging of the subsurface within the deeper parts of the fjord. Glacio-tectonic deformation is observed at both the northern and southern edge of the fjord. To the north, the deformation is expressed by complex internal reflection patterns within discrete sedimentary units including faults and smaller thrust-structures and associated small-scale folding. Channel incisions and clear reflection relations (i.e. truncations, onlaps and downlaps) reveal more decollement surfaces and furthermore constrain the timing of deformation. At least three episodes of deformation can be recognized at the northern edge of the fjord. To the south, a large thrusted fold belt (c. 3 km long and up to 10 m high) with faults, folds and thrust sheets is observed indicating severe deformation which most likely reflects ice progression from a southerly direction; for instance by the Young Baltic Ice Stream c. 19-17 ka. A thick and

  11. Forestry timber typing. Tanana demonstration project, Alaska ASVT. [Alaska

    NASA Technical Reports Server (NTRS)

    Morrissey, L. A.; Ambrosia, V. G.

    1982-01-01

    The feasibility of using LANDSAT digital data in conjunction with topographic data to delineate commercial forests by stand size and crown closure in the Tanana River basin of Alaska was tested. A modified clustering approach using two LANDSAT dates to generate an initial forest type classification was then refined with topographic data. To further demonstrate the ability of remotely sensed data in a fire protection planning framework, the timber type data were subsequently integrated with terrain information to generate a fire hazard map of the study area. This map provides valuable assistance in initial attack planning, determining equipment accessibility, and fire growth modeling. The resulting data sets were incorporated into the Alaska Department of Natural Resources geographic information system for subsequent utilization.

  12. Mapping the spatial variations of the hydrographic properties of warm subtropical-origin waters penetrating the previously unmapped glacial fjords of Northwest Greenland

    NASA Astrophysics Data System (ADS)

    Fenty, I. G.; Rignot, E. J.; Willis, J. K.

    2015-12-01

    Motivated by the widely-recognized need to understand the possible connection between the warming subpolar North Atlantic Ocean and the increasing contribution to sea level rise due to ice mass loss from the Greenland Ice Sheet multiple hydrographic and bathymetric surveys were conducted in the summer 2015 under the aegis of the NASA sub-orbital mission, Oceans Melting Greenland (OMG). Here, we report for the first time on the spatial variations of the hydrographic properties of the warm, subsurface subtropical-origin waters penetrating the numerous previously unmapped glacial fjords of Northwest Greenland spanning more than 1000 km of coast between Upernavik Fjord (73°N) and Inglefield Gulf (77.5°N). To interpret the distribution of hydrographic properties of these warm subsurface waters above the inner continental shelf and within glacial fjords, we analyze more than 5500 km of new high-resolution swath bathymetry and 1000 km of single-beam bathymetry data. These new bathymetry data reveal a network of deep troughs within which warm subsurface waters can penetrate from the continental shelf into glacial fjords and numerous shallow sills and ledges that inhibit the warm water contact with glacial termini. While these new hydrographic data are synoptic and therefore cannot reveal information about hydrographic temporal variability, the positive identification of warm waters in some glacial fjords in mid to late summer when subglacial discharge-fueled submarine melting is greatest provides useful information about the vulnerability of certain marine-terminating glaciers to future ocean-forced thinning, retreat, and acceleration.

  13. 76 FR 303 - Alaska: Adequacy of Alaska's Municipal Solid Waste Landfill Permit Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    ... From the Federal Register Online via the Government Publishing Office ] ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 239 and 258 Alaska: Adequacy of Alaska's Municipal Solid Waste Landfill Permit... proposes to approve Alaska's modification of its approved Municipal Solid Waste Landfill (MSWLF)...

  14. Fisheries Education in Alaska. Conference Report. Alaska Sea Grant Report 82-4.

    ERIC Educational Resources Information Center

    Smoker, William W., Ed.

    This conference was an attempt to have the fishing industry join the state of Alaska in building fisheries education programs. Topics addressed in papers presented at the conference include: (1) fisheries as a part of life in Alaska, addressing participation of Alaska natives in commercial fisheries and national efforts; (2) the international…

  15. Alaska Native Participation in the Civilian Conservation Corps. Alaska Historical Commission Studies in History No. 206.

    ERIC Educational Resources Information Center

    Sorensen, Connor; And Others

    The report is a finding aid to the sources which document the 1937 federal policy decision mandating that 50% of the enrollees in the Civilian Conservation Corps (CCC) in Alaska must be Alaska Natives and provides a list of the Native CCC projects in Alaska. The finding aid section is organized according to the location of the collections and…

  16. Interlaminated ice-proximal glacimarine sediments in Muir Inlet, Alaska

    USGS Publications Warehouse

    Mackiewicz, N.E.; Powell, R.D.; Carlson, P.R.; Molnia, B.F.

    1984-01-01

    Muir Inlet in Glacier Bay, Alaska, is a glacial fjord receiving a tremendous volume of sediment annually. The rate of sediment accumulation is greatest proximal to Muir Glacier (about 9 m yr-1) and decreases away from the glacier. The primary sediment sources are meltwater streams discharging at subglacial and ice-marginal positions to form overflows, interflows, and underflows (continuous turbidity currents). Overflows and interflows interact with diurnal tidal currents and their volume and sediment concentration varies diurnally and annually with meltwater discharge. These effects produce cyclic deposits of a thin fine-grained sand or silt lamina that grades normally to a thicker poorly to very poorly sorted mud lamina. This lamina couplet is termed a cyclopel. Underflows are suggested to occur in this glacimarine environment because of conditions unique to subglacial fluvial systems. Underflow deposits occur only in proximal positions (177 ??m) is ubiquitous, though low (<5% by weight), and occurs as isolated particles, frozen pellets, or as lenses that in cores may have a lamina appearance. Proximally, ice-rafted debris is difficult to identify because proximal sediment is often as coarse-grained. Deposited sediment may be reworked by tidal currents, and sediment gravity flows. Depositional processes operating in Muir Inlet produce interlaminated sand/silt/clay that characterizes sediment proximal to a glacier and fines seaward to mud. Sediment is classified into one of three sediment types: 1. (1) Type I sediment is very fine grained (mean 8.65-7.17 ??), low in sand (0.1-11.2%), and very poorly to poorly sorted. It is the dominant sediment type in Muir Inlet, and is transported by plumes and deposited by suspension settling. 2. (2) Type II sediment is fine- to coarse-grained (mean 6.70-3.12 ??), low to high in sand (5.1-86.6%), and very poorly to moderately sorted. It represents reworked sediment, proximal plume deposits, or coarse-grained laminae of cyclopels

  17. Reconstruction of the past 2000 years of ocean and glacier variability in Sermilik Fjord, SE Greenland, based on sediment archives

    NASA Astrophysics Data System (ADS)

    Stoican, Andreea; Andresen, Camilla; Seidenkrantz, Marit-Solveig; Kjaer, Kurt; Kuijpers, Antoon; Massé, Guillaume; Weckström, Kaarina

    2013-04-01

    Glaciomarine sediments represent valuable archives of climate and glacier variability in the arctic environment. Especially the fjords along Greenland's east coast represent a dynamic and complicated system, influenced by regional ocean circulation, local currents and by glacier terminations. Therefore, they represent appropriate locations for sedimentary core studies in order to detect the relative glacier and ocean variability. The aim of this project is to reconstruct the past 2000 years of glacier and ocean variability in Sermilik fjord, SE Greenland, into which Helheim glacier terminates. This is done by analysing two sedimentary cores (ER11 and ER07) and hereby reconstruct fluctuations in marine-terminating outlet glacier dynamics (including iceberg and to a lesser extent melt water production) and the interaction with oceanographic changes. The oceanographic variability is reconstructed on the basis of benthic and planktonic foraminiferal analysis and the content of the biomarker IP25 and these proxies are interpreted to reflect changes in the inflow of the warm Irminger Current and polar waters in association with the East Greenland Current. Interestingly, studies show that the onset of the Little Ice Age was characterised by intensified inflow of Irminger Current water masses to the Southeastern and Southwestern shelves of Greenland and that these may be associated with a contracted subpolar gyre. At the same time, the EGC Polar Water transport also intensified leading to a stratified water column on the shelf and this may have favoured entrainment of warm subsurface IC waters. Alternatively, the relatively warm rim of the eastern subpolar gyre may have promoted intense submarine melting of extended outlet glaciers at this time, producing enhanced melt water outflow which favoured estuarine circulation processes maintaining the inflow of IC water masses. Thus the aim of this study is to investigate in detail the circulation of these LIA warm waters from

  18. Seasonal variability of Dinophysis spp. and Protoceratium reticulatum associated to lipophilic shellfish toxins in a strongly stratified Chilean fjord

    NASA Astrophysics Data System (ADS)

    Alves-de-Souza, Catharina; Varela, Daniel; Contreras, Cristóbal; de La Iglesia, Pablo; Fernández, Pamela; Hipp, Byron; Hernández, Cristina; Riobó, Pilar; Reguera, Beatriz; Franco, José M.; Diogène, Jorge; García, Carlos; Lagos, Néstor

    2014-03-01

    The fine scale vertical distribution of Dinophysis spp. and Protoceratium reticulatum (potential producers of lipophilic shellfish toxins, LSTs) and its relation with LSTs in shellfish was studied in Reloncaví fjord, a strongly stratified system in Southern Chile. Samples were taken over two years from late spring to early autumn (2007-2008 period) and from early spring to late summer (2008-2009 period). Dinophysis spp., in particular Dinophysis acuminata, were always detected, often forming thin layers in the region of the salinity driven pycnocline, with cell maxima for D. acuminata of 28.5×103cellsL-1 in March 2008 and 17.1×103cellsL-1 in November 2008. During the 2008-2009 sampling period, blooms of D. acuminata co-occurred with high densities of cryptophyceans and the ciliate Mesodinium spp. The highest levels of pectenotoxin-2 (PTX-2; 2.2ng L-1) were found in the plankton in February 2009, associated with moderate densities of D. acuminata, Dinophysis tripos and Dinophysis subcircularis (0.1-0.6×103cellsL-1). However, only trace levels of PTX-2 were observed in bivalves at that time. Dinophysistoxin (DTX-1 and DTX-3) levels in bivalves and densities of Dinophysis spp. were not well correlated. Low DTX levels in bivalves observed during a major bloom of D. acuminata in March 2008 suggested that there is a large seasonal intraspecific variability in toxin content of Dinophysis spp. driven by changes in population structure associated with distinct LST toxin profiles in Reloncaví fjord during the study period. A heterogeneous vertical distribution was also observed for P. reticulatum, whose presence was restricted to summer months. A bloom of this species of 2.2×103cellsL-1 at 14m depth in February 2009 was positively correlated with high concentrations of yessotoxins in bivalves (51-496ngg-1) and plankton samples (3.2ngL-1). Our results suggest that a review of monitoring strategies for Dinophysis spp. in strongly stratified fjord systems should be

  19. Linked models to assess the impacts of climate change on nitrogen in a Norwegian river basin and FJORD system.

    PubMed

    Kaste, Ø; Wright, R F; Barkved, L J; Bjerkeng, B; Engen-Skaugen, T; Magnusson, J; Saelthun, N R

    2006-07-15

    Dynamically downscaled data from two Atmosphere-Ocean General Circulation Models (AOGCMs), ECHAM4 from the Max-Planck Institute (MPI), Germany and HadAm3H from the Hadley Centre (HAD), UK, driven with two scenarios of greenhouse gas emissions (IS92a and A2, respectively) were used to make climate change projections. These projections were then used to drive four effect models linked to assess the effects on hydrology, and nitrogen (N) concentrations and fluxes, in the Bjerkreim river basin (685-km(2)) and its coastal fjord, southwestern Norway. The four effect models were the hydrological model HBV, the water quality models MAGIC, INCA-N and the NIVA FJORD model. The downscaled climate scenarios project a general temperature increase in the study region of approximately 1 degrees C by 2030-2049 (MPI IS92a) and approximately 3 degrees C by 2071-2100 (HAD A2). Both scenarios imply increased winter precipitation, whereas the projections of summer and autumn precipitation are quite different, with the MPI scenario projecting a slight increase and the HAD scenario a significant decrease. As a response to increased winter temperature, the HBV model simulates a dramatic reduction of snow accumulation in the upper parts of the catchment, which in turn lead to higher runoff during winter and lower runoff during snowmelt in the spring. With the HAD scenario, runoff in summer and early autumn is substantially reduced as a result of reduced precipitation, increased temperatures and thereby increased evapotranspiration. The water quality models, MAGIC and INCA-N project no major changes in nitrate (NO(3)(-)) concentrations and fluxes within the MPI scenario, but a significant increase in concentrations and a 40-50% increase in fluxes in the HAD scenario. As a consequence, the acidification of the river could increase, thus offsetting ongoing recovery from acidification due to reductions in acid deposition. Additionally, the increased N loading may stimulate growth of N

  20. Linked models to assess the impacts of climate change on nitrogen in a Norwegian river basin and FJORD system.

    PubMed

    Kaste, Ø; Wright, R F; Barkved, L J; Bjerkeng, B; Engen-Skaugen, T; Magnusson, J; Saelthun, N R

    2006-07-15

    Dynamically downscaled data from two Atmosphere-Ocean General Circulation Models (AOGCMs), ECHAM4 from the Max-Planck Institute (MPI), Germany and HadAm3H from the Hadley Centre (HAD), UK, driven with two scenarios of greenhouse gas emissions (IS92a and A2, respectively) were used to make climate change projections. These projections were then used to drive four effect models linked to assess the effects on hydrology, and nitrogen (N) concentrations and fluxes, in the Bjerkreim river basin (685-km(2)) and its coastal fjord, southwestern Norway. The four effect models were the hydrological model HBV, the water quality models MAGIC, INCA-N and the NIVA FJORD model. The downscaled climate scenarios project a general temperature increase in the study region of approximately 1 degrees C by 2030-2049 (MPI IS92a) and approximately 3 degrees C by 2071-2100 (HAD A2). Both scenarios imply increased winter precipitation, whereas the projections of summer and autumn precipitation are quite different, with the MPI scenario projecting a slight increase and the HAD scenario a significant decrease. As a response to increased winter temperature, the HBV model simulates a dramatic reduction of snow accumulation in the upper parts of the catchment, which in turn lead to higher runoff during winter and lower runoff during snowmelt in the spring. With the HAD scenario, runoff in summer and early autumn is substantially reduced as a result of reduced precipitation, increased temperatures and thereby increased evapotranspiration. The water quality models, MAGIC and INCA-N project no major changes in nitrate (NO(3)(-)) concentrations and fluxes within the MPI scenario, but a significant increase in concentrations and a 40-50% increase in fluxes in the HAD scenario. As a consequence, the acidification of the river could increase, thus offsetting ongoing recovery from acidification due to reductions in acid deposition. Additionally, the increased N loading may stimulate growth of N