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Sample records for kenai fjords alaska

  1. Ecological overview of Kenai Fjords National Park

    USGS Publications Warehouse

    Spencer, Page; Irvine, Gail V.

    2004-01-01

    The major drivers of Kenai Fjords ecosystems are tectonics and climate. In this overview, we describe how these forces have contributed to the shaping of the lands and ecosystems of Kenai Fjords.Physically, the park is comprised of several distinct components, set within a broader ecophysical framework that includes the Kenai Peninsula and coastal marine waters and islands. Squeezed between the Gulf of Alaska and the Kenai Mountains, the coastal zone of the park is a narrow band of exposed headlands and deep fjords. The Harding Icefield caps the Kenai Mountains above the fjords with ice estimated to be 3,000 feet (1,000 m) thick (Figure 1). Although not included in the National Park Service jurisdiction, the park is ecologically linked to the offshore marine ecosystem, and the embedded offshore islands, most of which are part of the Alaska Maritime National Wildlife Refuge, managed by the U.S. Fish and Wildlife Service.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. Gulf Watch Alaska nearshore component: Monitoring site locations from Prince William Sound, Katmai National Park and Preserve, and Kenai Fjords National Park

    USGS Publications Warehouse

    Coletti, Heather A.; Kloecker, Kim; Bodkin, James L.; Dean, Thomas A.

    2017-01-01

    These data are part of the Gulf Watch Alaska (GWA) long term monitoring program, nearshore monitoring component. Specifically, these data describe site locations for rocky intertidal, mussel sampling, soft sediment bivalve sampling, and eelgrass bed sampling in the northern Gulf of Alaska within the GWA program. The dataset consists of two comma separated files exported from a Microsoft Excel workbook. The data consists of 1. rocky intertidal, mussel sampling, and soft sediment site location information, and 2. eelgrass bed locations. Sampling will be conducted in Katmai National Park and Preserve (KATM), Kenai Fjords National Park (KEFJ), Prince William Sound (PWS) and to a lesser extent on the Lake Clark National Park and Preserve (LACL). Sites from a related project that provides similar data from Kachemak Bay (KBAY) are included here.

  7. 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

  8. 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.

  9. 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.

  10. 33 CFR 162.245 - Kenai River, Kenai, Alaska; use, administration, and navigation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Kenai River, Kenai, Alaska; use, administration, and navigation. 162.245 Section 162.245 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.245 Kenai River, Kenai, Alaska; use, administration, and navigation. (a) The area. The main...

  11. 33 CFR 162.245 - Kenai River, Kenai, Alaska; use, administration, and navigation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Kenai River, Kenai, Alaska; use, administration, and navigation. 162.245 Section 162.245 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.245 Kenai River, Kenai, Alaska; use, administration, and navigation. (a) The area. The main...

  12. 33 CFR 162.245 - Kenai River, Kenai, Alaska; use, administration, and navigation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Kenai River, Kenai, Alaska; use, administration, and navigation. 162.245 Section 162.245 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.245 Kenai River, Kenai, Alaska; use, administration, and navigation. (a) The area. The main...

  13. 33 CFR 162.245 - Kenai River, Kenai, Alaska; use, administration, and navigation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Kenai River, Kenai, Alaska; use, administration, and navigation. 162.245 Section 162.245 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 162.245 Kenai River, Kenai, Alaska; use, administration, and navigation. (a) The area. The main...

  14. Population status of Kittlitz's and Marbled Murrelets and surveys for other marine bird and mammal species in the Kenai Fjords area, Alaska

    USGS Publications Warehouse

    van Pelt, Thomas I.; Piatt, John F.

    2003-01-01

    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. More than 95% of the global population breeds in Alaska, with the remainder occurring in the Russian Far East. A global population estimate using best-available data in the early 1990s was 20,000 individuals. However, survey data from two core areas (Prince William Sound and Glacier Bay) suggest that populations have declined by 80-90% during the past 10-20 years. In response to these declines, a coalition of environmental groups petitioned the USFWS in May of 2001 to list the Kittlitz’s murrelet under the Endangered Species Act. In 2002, we began a three-year project to examine population status and trend of Kittlitz’s Murrelets in areas where distribution and abundance are poorly known. Here we report on the first field season, focused on the south coast of the Kenai Peninsula. We re-surveyed selected historical transects to evaluate trends, and surveyed new transects for improved population estimation during early July 2002. From a total of 66 Kittlitz’s Murrelets seen on transects, we estimate a total population of 509 Kittlitz’s Murrelets along the south coast of the Kenai Peninsula. Comparisons with past surveys suggest a decline of 83% since 1976, with an average rate of decline calculated as–6.9 % per annum. This decline is in agreement with population declines observed elsewhere in the species’ core glaciated range, indicating that steep population declines observed to date are likely to be a range-wide phenomenon. While the focus of the study was Kittlitz’s Murrelets, other species of marine birds and mammals were also surveyed. Populations of the closely related Marbled Murrelet appear to have increased during the same time period. The abundance and distribution of other species are presented in appendices.

  15. Glaciers in Kenai Fjords NP: Exploration and Change

    NASA Astrophysics Data System (ADS)

    Phillips, E.; Molnia, B.

    2004-12-01

    In 1909, USGS geologists U.S. Grant and D. F. Higgins mapped and photographed all of the tidewater glaciers and many of the land-terminating outlet glaciers in what is now Kenai Fjords National Park, creating a thorough record of glacier terminus positions and heights. In August, 2004, with funding from the National Park Service and the USGS Earth Surface Dynamics Program, we conducted a new photo survey in Grant and Higgins' footsteps. We re-established 40 of their photo stations with a confidence level of approximately 5-30 feet. We located the sites by identifying foreground features and by analyzing the extent of overlap of mountain peaks in the 1909 photo backgrounds. WAAS-enabled GPS was used to determine the location of each station for future surveys. At each station, we took new photographs duplicating the field of view shown in the 1909 photographs and also showing panoramic views. At most locations, the change in glacier height and terminus position since 1909 has been dramatic. At several stations, glacier termini were no longer visible. Northwestern Glacier, for example, has retreated around a series of bends in its valley. In some cases, vegetation completely obstructed the view from the 1909 photo station. In these instances, new GPS-located photo stations were established within sight of the present day termini. To illustrate the changes for the public, a dozen photographic pairs have been turned into animated GIFs using MacroMedia Flash. Each animation begins with a 1909 Grant and Higgins photograph which fades into the 2004 image. The two images have been correlated by matching topographic features. The animations clearly depict changes in vegetation, glacier cover, and geomorphologic features that have taken place in the last 95 years.

  16. Paleoseismic Investigations of Subduction Zone Earthquakes on the Southeastern Coast of the Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Kelsey, H. M.; Witter, R. C.; Briggs, R. W.; Engelhart, S. E.; Nelson, A. R.; Haeussler, P. J.

    2013-12-01

    Rupture extents for prehistoric subduction zone earthquakes on the Alaska margin are poorly documented. For example, the 1964 great Alaska earthquake ruptured the subduction zone from Prince William Sound westward to the southwest end of Kodiak Island, but an outstanding question is whether or not earlier subduction earthquakes ruptured a shorter segment in the Kodiak region with the eastern margin located in the Kenai Peninsula. To address the question, we investigated several embayments on the Pacific (southeastern) coast of the Kenai Peninsula to reconstruct the late Holocene paleoseismic history. Constraints to constructing a paleoseismic history on the outer Kenai coast include recent deglaciation of embayments that limits a stratigraphic record to approximately the last 1 to 3 thousand years and the high wave-energy environment that results in frequent closure of embayments by barrier bars. Recognizing these constraints, two approaches have proved productive in investigating paleoseismic history on the outer Kenai coast. One involves understanding how beach ridges can be formed and modified by coseismic subsidence and documenting timing and number of late Holocene prehistoric earthquakes based on beach ridge genesis and evolution. The other approach, which is the more conventional paleoseismic approach for subduction zones, is investigating stratigraphic evidence for coseismic subsidence in peaty and muddy sediment within embayments. We illustrate these two approaches using two coastal sites in Aialik Bay within Kenai Fjords National Park, a strandplain complex at Verdant Cove and a drowned embayment at Quicksand Cove, respectively. Both sites record two prehistoric subduction zone earthquakes prior to the historically known 1964 great Alaska earthquake.

  17. Blueberry Trials on Alaska's Kenai Peninsula: First Year Report

    USDA-ARS?s Scientific Manuscript database

    In June 2009, 9 plants each of three highbush and six half-high blueberry cultivars were planted at test plots on two commercial farms on Alaska's Kenai Peninsula. The purpose of the trials was to determine if domestic blueberry plants could survive and produce crops in Southcentral Alaska. In Octob...

  18. Spruce reproduction dynamics on Alaska's Kenai Peninsula, 1987-2000.

    Treesearch

    Willem W.S. van Hees

    2005-01-01

    During the past 30 years, spruce forests of Alaska’s Kenai Peninsula have undergone dramatic changes resulting from widespread spruce bark beetle(Dendroctonus rufipennis (Kirby)) infestation. In 1987 and again in 2000, the Pacific Northwest Research Station's Forest Inventory and Analysis Program conducted initial and remeasurement inventories...

  19. Preliminary classification of forest vegetation of the Kenai Peninsula, Alaska.

    Treesearch

    K.M. Reynolds

    1990-01-01

    A total of 5,597 photo points was systematically located on 1:60,000-scale high altitude photographs of the Kenai Peninsula, Alaska; photo interpretation was used to classify the vegetation at each grid position. Of the total grid points, 12.3 percent were classified as timberland; 129 photo points within the timberland class were randomly selected for field survey....

  20. Periglacial Landforms and Processes in the Southern Kenai Mountains, Alaska.

    DTIC Science & Technology

    1980-05-01

    were investigated during the sumr of 1979. The principal area of study was a 1300-metre high mountain mass which stood as a nunatak during the last...Mountains, Alaska, were investigated during the summer of 1979. The principal area of study was a 1300-metre high mountain mass which stood as a nunatak ...Kenai Mountains as not having been covered by ice since the Eklutna glaciation. These areas would have thus stood as nunataks during subsequent

  1. 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.

  2. Boat-Wave-Induced Bank Erosion on the Kenai River, Alaska

    DTIC Science & Technology

    2008-03-01

    lower Kenai River. .......................60 Figure 36. Hydrograph of the Kenai River at Soldotna...and reviewed study plans and draft reports. • Chris Degernes and Jack Sinclair of the Alaska Department of Natural Resources (ADNR), Division of...locating study sites, reviewed study plans and draft reports, and provided expert advice and assistance. ERDC TR-08-5 ix • Dean Hughes, ADF&G

  3. 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

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Kenai Pipe Line Company; Tesoro Alaska Company; Tesoro Logistics Operations... Company (Tesoro Alaska), and Tesoro Logistics, LLC (TLO) (collectively, Tesoro) filed a Request for...

  4. 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

  5. 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 in...

  6. Erosion and sedimentation in the Kenai River, Alaska

    USGS Publications Warehouse

    Scott, Kevin M.

    1981-01-01

    The Kenai River is the most important freshwater fishery in Alaska. The flow regime is characterized by high summer flow of glacial meltwater and periodic flooding caused by sudden releases of glacier-dammed lakes in the headwaters. Every part of the stream is a known or potential salmon-spawning site. The stream channel is underfit, attributed to regional glacial recession and drainage changes, and locally is entrenched in response to geologically recent changes in base level. Throughout the central section of the river the channel is armored, a condition with implications for the ability of this section of channel to support the spawning and rearing of salmon. The entrenched section of the channel has been stable since 1951. Bank erosion is active both upstream and downstream from the entrenched channel, however. Although erosion rates have been generally constant since 1951, evidence suggests a possible recent decrease in bank stability that may be related to changes in river use. As population and recreation use increases, development can pose a hazard to the productivity of the stream through increased suspended-sediment concentration resulting directly from construction and, with greater potential for long-term impact, indirectly from bank erosion. A short-term hazard to both stream and developments is the cutoff of meander loops, the risk of which is increased by canals and boat slips cut in the surface layer of cohesive, erosion-resistant sediment on the flood plain within nonentrenched meander loops. A long-term hazard is an increase in bank erosion rates resulting from loss of vegetation on the high (up to 70 feet) cutbanks of entrenched and partially entrenched sections. (USGS)

  7. Erosion and sedimentation in the Kenai River, Alaska

    USGS Publications Warehouse

    Scott, Kevin M.

    1982-01-01

    The Kenai River is the most important freshwater fishery in Alaska. The flow regime is characterized by high summer flow of glacial meltwater and periodic flooding caused by sudden releases of glacier-dammed lakes in the headwaters. Every part of the stream is a known or potential salmon-spawning site. The stream channel is underfit, attributed to regional glacial recession and drainage changes, and locally is entrenched in response to geologically recent changes in base level. Throughout the central section of the river the channel is armored, a condition with implications for the ability of this section of channel to support the spawning and rearing of salmon. The entrenched section of the channel has been stable since 1951. Bank erosion is active both upstream and downstream from the entrenched channel, however. Although erosion rates have been generally constant since 1951, evidence suggests a possible recent decrease in bank stability that may be related to changes in river use. As population and recreation use increases, development can pose a hazard to the productivity of the stream through increased suspended-sediment concentration resulting directly from construction and, with greater potential for long-term impact, indirectly from bank erosion. A short-term hazard to both stream and developments is the cutoff of meander loops, the risk of which is increased by canals and boat slips cut in the surface layer of cohesive, erosion-resistant sediment on the flood plain within nonentrenched meander loops. A long-term hazard is an increase in bank erosion rates resulting from loss of vegetation on the high (up to 70 feet) cutbacks of entrenched and partially entrenched section. (USGS)

  8. Changes in downed and dead woody material following a spruce beetle outbreak on the Kenai Peninsula, Alaska.

    Treesearch

    Bethany. Schulz

    2003-01-01

    The forests of the Kenai Peninsula, Alaska, underwent a major spruce beetle(Dendroctonus rufipennis (Kirby)) outbreak in the 1990s. A repeated inventory of forest resources was designed to assess the effects of the resulting widespread mortality of spruce trees, the dominant component of the Kenai forests. Downed woody materials, fuel heights, and...

  9. Feasibility of using wood wastes to meet local heating requirements of communities in the Kenai Peninsula in Alaska.

    Treesearch

    David L. Nicholls; Peter M. Crimp

    2002-01-01

    Wood energy can be important in meeting the energy needs of Alaska communities that have access to abundant biomass resources. In the Kenai Peninsula, a continuing spruce bark beetle (Dendroctonus rufipennis (Kirby)) infestation has created large volumes of standing dead spruce trees (Picea spp.). For this evaluation, a site in the Kenai-Soldotna...

  10. Paleo-perspectives on dynamic coastal change, James Lagoon, Kenai Fjords National Park.

    NASA Astrophysics Data System (ADS)

    Maio, C. V.; Sullivan, R.

    2016-12-01

    The coastlines of southcentral Alaska are some of the most dynamic in the world, experiencing rapid and sometimes catastrophic environmental change. Given the multiple drivers of coastal change operating in the region, it is often difficult to discern the timing and character of the individual processes driving coastal evolution, hindering the accurate assessment of current risks associated with coastal hazards. To contribute towards the understanding of the nature, mechanisms, and timing of coastal change in the region, this research seeks to decipher the rich sedimentary archive of James Lagoon, a drowned cirque basin located on the margin of a deep-water fjord. An acoustic sub-bottom profiler was used to map the geometry and sedimentary archive of the basin. Gravity cores reaching a sediment depth of 1.6 m were collected from the deepest portions of the lagoon (30 m), while sediments from a fringing freshwater marsh were sampled with a Russian peat corer. Grain size and loss-on-ignition analysis combined with radiometric dating is currently being carried out within the lab. Acoustic profiles of the lagoon document 30 m of stratified sediments punctuated by narrow high-amplitude reflectors indicative of transitions between high and low energy deposition. Both marsh and lagoon cores contain inorganic coarse-grain horizons interbedded with organic rich peat and silt. Two samples of articulated bivalves from the lagoon cores (depths of 97 cm and 102 cm respectively) date to 486 and 554 median cal BP. Within the marsh, a basal (118 cm) radiocarbon date of 614 median cal BP provides a limiting age for overwash deposits identified within the cores. Data indicates that the site has been impacted by low frequency high energy events characteristic of tsunamis or extreme storms. Further analysis of event beds is needed to determine the specific mechanism behind their deposition.

  11. 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.

  12. 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.

  13. Vegetation response to prescribed fire in the Kenai Mountains, Alaska.

    Treesearch

    Tina V. Boucher

    2003-01-01

    Between 1977 and 1997, 4000 ha were burned to promote regeneration of tree and shrub species used for browse by moose (Alces alces) in the Kenai Mountains. Species composition was documented along burned and unburned transects at 17 prescribed burn sites. Relationships among initial vegetation composition, physical site characteristics, browse...

  14. Timberland resources of the Kenai Peninsula, Alaska, 1987.

    Treesearch

    Willem W.S. van Hees; Frederic R. Larson

    1991-01-01

    The 1987 inventory of the forest resources of the Kenai Peninsula was designed to assess the impact of the spruce beetle (Dendroctonus rufipennis (Kirby)) on the timberland component of the forest resource. Estimates of timberland area, volumes of timber, and growth and mortality of timber were developed. These estimates of timber resource...

  15. Late Quaternary Tephrochronology From Three Lakes, Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    de Fontaine, C. S.; Kaufman, D. S.; Anderson, R.; Werner, A.; Waythomas, C. F.; Wallace, K. L.

    2003-12-01

    Tustumena, Paradox, and Jigsaw Lakes, located 60-120 km southwest of Anchorage, Alaska, on the Kenai Peninsula, were cored to evaluate the conditions best suited for the preservation of tephra, and to determine the ages and frequency of ash fall associated with regional volcanic eruptions. The lakes are located downwind of the eastern Aleutian Arc, where they are likely to receive tephra fallout, especially from Augustine, Iliamna, Redoubt, Spurr and Hayes Volcanoes. The lakes are close together (<60 km), so differences among their tephra records should primarily reflect lake-dependent processes and features, although variations in individual tephra plumes may preclude deposition in all the lakes. Multiple cores from each lake were analyzed to locate tephra using magnetic susceptibility (MS) and petrographic techniques (all tephra were found to have high MS). Tephra beds are typically light-gray ash, 1-2 mm thick, and are composed of glass shards and pumice (commonly 0.06-0.3 mm diameter), and varying proportions of glass-coated phenocrysts. Most are relatively pure, suggesting primary deposition with minor subsequent reworking. Core depth-age models were derived based on 28 radiocarbon ages on plant macrofossils preserved in the stratigraphy. Of the three lakes, sediment from Paradox Lake recorded the greatest frequency of tephra-fall events: 6.1 tephra/ka (81 over the 13,200-cal-yr record). Sediment from Jigsaw and Tustumena Lakes contains only 1.1 and 1.9 tephra/ka over their 9700-cal-yr records. Paradox Lake is better suited for tephra preservation compared to Tustumena and Jigsaw Lakes because, (1) it is small (0.11 km2) yet has a relatively large drainage-basin-to-lake area ratio of more that 5 times the other lakes for accumulating tephra; (2) it is situated in a narrow (ca. 0.6 km), steep-sided (10-18° ) valley that focuses tephra deposition and shelters the lake from wind-driven mixing (the other lakes are more exposed and susceptible to wind

  16. Periglacial Landforms and Processes in the Southern Kenai Mountains, Alaska.

    DTIC Science & Technology

    1985-04-01

    mountain masses are continuous (Capps 1940). They are composed primarily of sedimentary rocks of Mesozoic age that have been highly deformed and, in...surface forms are the result of extensive glacial erosion (Capps 1940). Two large icefields still exist: the Sargent icefield, in the * extreme eastern ...Studies Economic Geology Most of the early geologic investigations on the Kenai Peninsula were studies of the gold and coal resources of the region

  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. Climate and vegetation history from a 14,000-year peatland record, Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Jones, Miriam C.; Peteet, Dorothy M.; Kurdyla, Dorothy; Guilderson, Thomas

    2009-09-01

    Analysis of pollen, spores, macrofossils, and lithology of an AMS 14C-dated core from a subarctic fen on the Kenai Peninsula, Alaska reveals changes in vegetation and climate beginning 14,200 cal yr BP. Betula expansion and contraction of herb tundra vegetation characterize the Younger Dryas on the Kenai, suggesting increased winter snowfall concurrent with cool, sunny summers. Remarkable Polypodiaceae (fern) abundance between 11,500 and 8500 cal yr BP implies a significant change in climate. Enhanced peat preservation and the occurrence of wet meadow species suggest high moisture from 11,500 to 10,700 cal yr BP, in contrast to drier conditions in southeastern Alaska; this pattern may indicate an intensification and repositioning of the Aleutian Low (AL). Drier conditions on the Kenai Peninsula from 10,700 to 8500 cal yr BP may signify a weaker AL, but elevated fern abundance may have been sustained by high seasonality with substantial snowfall and enhanced glacial melt. Decreased insolation-induced seasonality resulted in climatic cooling after 8500 cal yr BP, with increased humidity from 8000 to 5000 cal yr BP. A dry interval punctuated by volcanic activity occurred between 5000 and 3500 cal yr BP, followed by cool, moist climate, coincident with Neoglaciation. Tsuga mertensiana expanded after ~ 1500 cal yr BP in response to the shift to cooler conditions.

  19. Physical, chemical, and biological data for two sites on the upper Kenai River, Alaska, 1998

    USGS Publications Warehouse

    Dorava, Joseph M.; Ness, Lee

    1999-01-01

    Water-quality data were collected and stream characteristics were documented from two sites along the upper Kenai River in the Kenai National Wildlife Refuge, Alaska. These data were collected to describe the current status of the sites and to provide baseline information from which changes in the future could be evaluated. Physical characteristics included channel geometry surveys, and measurements of channel widths and water discharge at each site. Chemical data included stream water temperature, dissolved-oxygen concentration, pH, specific conductance, E. coli and fecal coliform counts, and nutrient concentration. Data on concentrations of trace elements and various organic compounds in bed sediments and the tissue of slimy sculpin were also collected. Biological characteristics were evaluated using measurements of the bacteria, benthic macroinvertebrate, and fish communities.

  20. 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.

  1. Distribution and density of marine birds and mammals along the Kenai Fjords National Park coastline - March 2010

    USGS Publications Warehouse

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

    2011-01-01

    From March 21, 2010 to March 24, 2010, a winter marine bird and mammal skiff-based survey along the coast of Kenai Fjords National Park (KEFJ) was completed. This was the second winter survey completed for KEFJ since 2008. The primary objectives of the SWAN winter surveys are to characterize the species composition, density and distribution of the overwintering marine ducks prior to their migration to breeding grounds. Seasonal differences in species composition, distribution and density of other marine birds and mammals are also documented. The overall design calls for the sampling of the same transects during both the winter and summer surveys if safe and appropriate conditions allow. The 2010 survey took approximately four days to complete with a crew of six. The most common birds observed on the nearshore transects were the Barrow’s goldeneye (29.35/km2 , SE=9.24) and harlequin duck (29.30/km2 , SE=4.72). Harlequin ducks tended to be more evenly distributed along the coastline while Barrow’s goldeneye tended to be observed in less exposed areas along the coast and in larger groups. In contrast, the most abundant marine bird in KEFJ summer surveys is the Glaucous-winged gull, while Barrow’s goldeneye are nearly absent along the KEFJ coast. The most common marine mammal was the harbor seal (6.75/km2 , se=2.93) followed by the sea otter (3.59/km2 , se=0.90, adults and pups). Densities of harbor seals and sea otters in the summer were similar to the winter estimates.

  2. 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.

  3. 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.

  4. 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.

  5. Landslide Hazard Mapping Using Ground-based Interferometric Radar in the Fjords of South-Central Alaska

    NASA Astrophysics Data System (ADS)

    Balazs, M. S.; Meyer, F. J.; Bollian, T.; Wolken, G. J.; Prakash, A.

    2013-12-01

    The cities of Seward and Whittier, Alaska are situated at the base of steep walls within two fjords located on the Kenai Peninsula. Historic events have shown that the combination of terrain, geology, and vegetation are factors which can lead to significant events of erosion in the surrounding slopes during periods of heavy rainfall. While other remote sensing techniques have been shown to be useful for accessing landslide hazards, local surface processes may be better understood to create more accurate hazard maps and predictive models by using data gained from interferometric radar. To gain perspective into where, and at which speed, slopes are deforming, we utilize the GPRI-2 terrestrial interferometric radar system which transmits signals in the Ku band. The GPRI-2 portable radar unit has several advantages to space-borne radar, including relative freedom of site selection and regions to target, ability to determine temporal baselines, and repeat acquisitions which can be collected with a zero spatial-baseline. There are however, problems which need to be addressed when using such a system in the fjord environments, and in particular for monitoring slope deformation in these areas. Foremost, the noise that is attributed to the atmosphere is of great concern as it is sometimes required to position the radar several kilometers away from the target, across open water. We offer our results of correcting for this interference and report the results. Secondly, we address the issue of repeat acquisitions over long periods of time, which is needed to detect movements in the slope, and report on the decorrelation of the signal in the various land cover types in the study areas. Finally, we offer suggestions of the usefulness of such a system to detect slope deformation in similar environments.

  6. 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

  7. 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.

  8. 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)

  9. 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.

  10. Influence of glacier runoff on ecosystem structure in Gulf of Alaska fjords

    USGS Publications Warehouse

    Arimitsu, Mayumi; Piatt, John F.; Mueter, Franz J.

    2016-01-01

    To better understand the influence of glacier runoff on fjord ecosystems, we sampled oceanographic conditions, nutrients, zooplankton, forage fish and seabirds within 4 fjords in coastal areas of the Gulf Alaska. We used generalized additive models and geostatistics to identify the range of glacier runoff influence into coastal waters within fjords of varying estuarine influence and topographic complexity. We also modeled the response of depth-integrated chlorophyll a concentration, copepod biomass, fish and seabird abundance to physical, nutrient and biotic predictor variables. The effects of glacial runoff were traced at least 10 km into coastal fjords by cold, turbid, stratified and generally nutrient-rich near-surface conditions. Glacially modified physical gradients, nutrient availability and among-fjord differences explained 67% of the variation in phytoplankton abundance, which is a driver of ecosystem structure at higher trophic levels. Copepod, euphausiid, fish and seabird distribution and abundance were related to environmental gradients that could be traced to glacial freshwater input, particularly turbidity and temperature. Seabird density was predicted by prey availability and silicate concentrations, which may be a proxy for upwelling areas where this nutrient is in excess. Similarities in ecosystem structure among fjords were attributable to an influx of cold, fresh and sediment-laden water, whereas differences were likely related to fjord topography and local differences in estuarine vs. ocean influence. We anticipate that continued changes in the timing and volume of glacial runoff will ultimately alter coastal ecosystems in the future.

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Operations within Misty Fjords and Admiralty Island National Monuments, Alaska. 228.80 Section 228.80 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE MINERALS Miscellaneous Minerals Provisions § 228.80...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

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

    USGS Publications Warehouse

    Carlson, Paul R.; Powell, Ross D.; Phillips, Andrew C.

    1992-01-01

    Side-scan sonar images provide a view of an actively changing delta front in a marine outwash fjord in Glacier Bay, Alaska. 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.

  19. 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.

  20. 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.

  1. An analytical method to assess spruce beetle impacts on white spruce resources, Kenai Peninsula, Alaska.

    Treesearch

    Willem W.S. van Hees

    1992-01-01

    Forest inventory data collected in 1987 fTom sample plots established on the Kenai Peninsula were analyzed to provide point-in-time estimates of the trend and current status of a spruce beetle infestation. Ground plots were categorized by stage of infestation. Estimates of numbers of live and dead white spruce trees, cubic-foot volume in those trees, and areal extent...

  2. Long Term Ecological Monitoring Program on the Kenai National Wildlife Refuge, Alaska: An FIA adjunct inventory

    Treesearch

    Bowser John M. Morton; Edward Berg; Dawn Magness; Todd Eskelin

    2009-01-01

    Kenai National Wildlife Refuge (KENWR) has a legislative mandate "to conserve fish and wildlife populations and habitats in their natural diversity". To improve our understanding of spatial and temporal variation at the landscape level, we are developing the Long Term Ecological Monitoring Program (LTEMP) to assess change in biota on the sample frame used by...

  3. Chapter 15: Inland Habitat Suitability for the Marbled Murrelet in Southcentral Alaska

    Treesearch

    Katherine J. Kuletz; Dennis K. Marks; Nancy L. Naslund; Nike J. Goodson; Mary B. Cody

    1995-01-01

    The majority of Marbled Murrelets (Brachyramphus marmoratus) nest in Alaska, where they sometimes nest on the ground, and their nesting habitat requirements are not well understood. The inland activity of murrelets was surveyed, and habitat features measured, between 1991 and 1993, in Prince William Sound, Kenai Fjords National Park and Afognak...

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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, John 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.

  9. 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.

  10. 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

  11. 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

  12. Highbush and Half-high Blueberry Trials on Alaska's Kenai Peninsula

    USDA-ARS?s Scientific Manuscript database

    While cultivation of domestic small fruits and harvesting of wild, native small fruits are popular in Alaska, little research has been published on the adaptability of highbush and half-high blueberries in southcentral Alaska. Although the area is subject to harsh winters and a short growing season,...

  13. 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

  14. Arthropod and oligochaete assemblages from grasslands of the southern Kenai Peninsula, Alaska

    PubMed Central

    Bowser, Matthew L.; Morton, John M.; Hanson, John Delton; Magness, Dawn R.; Okuly, Mallory

    2017-01-01

    Abstract Background By the end of this century, the potential climate-biome of the southern Kenai Peninsula is forecasted to change from transitional boreal forest to prairie and grasslands, a scenario that may already be playing out in the Caribou Hills region. Here, spruce (Picea × lutzii Little [glauca × sitchensis]) forests were heavily thinned by an outbreak of the spruce bark beetle (Dendroctonus rufipennis (Kirby, 1837)) and replaced by the native but invasive grass species, Calamagrostis canadensis (Michx.) P. Beauv. As part of a project designed to delimit and characterize potentially expanding grasslands in this region, we sought to characterize the arthropod and earthworm communities of these grasslands. We also used this sampling effort as a trial of applying high-throughput sequencing metabarcoding methods to a real-world inventory of terrestrial arthropods. New information We documented 131 occurrences of 67 native arthropod species at ten sites, characterizing the arthropod fauna of these grasslands as being dominated by Hemiptera (60% of total reads) and Diptera (38% of total reads). We found a single exotic earthworm species, Dendrobaena octaedra (Savigny, 1826), at 30% of sites and one unidentified enchytraeid at a single site. The utility of high-throughput sequencing metabarcoding as a tool for bioassessment of terrestrial arthropod assemblages was confirmed. PMID:28325976

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

    USDA-ARS?s Scientific Manuscript database

    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...

  16. 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.

  17. 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.

  18. Digital Data for the reconnaissance geologic map for Prince William Sound and the Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Wilson, Frederic H.; Hults, Chad P.; Labay, Keith A.; Shew, Nora B.

    2007-01-01

    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

  19. Reconnaissance bedrock geology of the southeastern part of the Kenai quadrangle, Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

    USGS Publications Warehouse

    Bradley, Dwight C.; Wilson, Frederic H.

    2000-01-01

    We present a new reconnaissance geologic map of the southeastern part of the Kenai quadrangle that improves on previously published maps. Melange of the McHugh Complex is now known to form a continuous strike belt that can be traced from the Seldovia to the Valdez quadrangle; a problematic 75-km-long gap in the McHugh Complex in the Kenai and Seldovia quadrangles does not exist. An Eocene near-trench pluton underlies a range of nunataks in Harding Icefield.

  20. New Imaging Of Submarine Landslides Near Whittier, Alaska, From The 1964 Earthquake And A Comparison To Other 1964 Failures In Alaskan Fjords

    NASA Astrophysics Data System (ADS)

    Haeussler, P. J.; Parsons, T.; Finlayson, D. P.; Hart, P. E.; Chaytor, J. D.; Ryan, H. F.; Lee, H. J.; Peterson, A. D.; Liberty, L. M.

    2012-12-01

    The 1964 Alaska M9.2 earthquake triggered numerous submarine slope failures in fjords along the southern Alaska margin. These failures generated local tsunamis, which were the single largest cause of deaths from the earthquake. We collected new multibeam bathymetry and sparker seismic data in Passage Canal, Alaska (the fjord near Whittier) to better map the location and characteristics of the 1964 and earlier submarine landslides. The 1964 earthquake triggered tsunamis that inundated the town of Whittier in three waves that hit within 4 minutes of the beginning of shaking. Run up was up to 12 m in the town and reached 25 m across the bay, with 13 casualties. All modern harbor and port facilities are within reach of the historic wave inundation. The new multibeam bathymetry reveals the debris field from the 1964 submarine landslide, which covers the fjord bottom up to 5 km from the head of the fjord. Individual debris blocks are up to 145-m across and 25-m tall. Mapping the debris lobes based on the seismic and geomorphology indicates all mass transfer deposits originated from the fjord head delta, not from rockfall from the fjord walls. The multibeam data also clearly reveal a submerged moraine, which impounds all debris flows originating in the uppermost part of the fjord. The seismic reflection data show the 1964 deposit having an average thickness of 6 m and a volume of 20 million cubic meters. We were unable to identify pre-1964 failures, despite imaging fjord sediments to more than 75 m below the bottom. We have now closely examined the 1964 submarine landslides in three fjords (Passage Canal near Whittier, Port Valdez near Valdez, and Resurrection Bay near Seward), and there are both similarities and considerable differences. All three involved failure of the fjord-head delta with deposition of mass transfer deposits in the flat fjord bottom. All three had erosive failures with slide volumes from seismic reflection data significantly larger than volumes based

  1. New imaging of submarine landslides from the 1964 earthquake near Whittier, Alaska, and a comparison to failures in other Alaskan fjords

    USGS Publications Warehouse

    Haeussler, Peter J.; Parsons, Thomas E.; Finlayson, David P.; Hart, Patrick J.; Chaytor, Jason D.; Ryan, Holly F; Lee, Homa J.; Labay, Keith; Peterson, Andrew; Liberty, Lee

    2014-01-01

    The 1964 Alaska M w 9.2 earthquake triggered numerous submarine slope failures in fjords of southern Alaska. These failures generated local tsunamis, such as at Whittier, where they inundated the town within 4 min of the beginning of shaking. Run-up was up to 32 m, with 13 casualties. We collected new multibeam bathymetry and high-resolution sparker seismic data in Passage Canal, and we examined bathymetry changes before and after the earthquake. The data reveal the debris flow deposit from the 1964 landslides, which covers the western 5 km of the fjord bottom. Individual blocks in the flow are up to 145-m wide and 25-m tall. Bathymetry changes show the mass transfer deposits originated from the fjord head and Whittier Creek deltas and had a volume of about 42 million m3. The 1964 deposit has an average thickness of ∼5.4 m. Beyond the debris flow, the failures likely deposited a ∼4.6-m thick megaturbidite in a distal basin. We have studied the 1964 submarine landslides in three fjords. All involved failure of the fjord-head delta. All failures eroded basin-floor sediments and incorporated them as they travelled. All the failures deposited blocks, but their size and travel distances varied greatly. We find a correlation between maximum block size and maximum tsunami run-up regardless of the volume of the slides. Lastly, the fjord’s margins were influenced by increased supply of glacial sediments during the little ice age, which along with a long interseismic interval (∼900 years) may have caused the 1964 earthquake to produce particularly numerous and large submarine landslides.

  2. 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

  3. The Kenai experience: communities and forest health.

    Treesearch

    Valerie. Rapp

    2005-01-01

    Over the last 15 years, spruce bark beetles have killed huge numbers of spruce trees, the dominant conifer across south-central Alaska. From 80 to 90 percent of the trees are dead in large areas on the Kenai Peninsula. The consequences of the spruce bark beetle outbreak will continue for years.

  4. 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.

  5. Preliminary Results of a Recent Gravity Survey Across the Border Ranges Fault System, Central Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Mankhemthong, N.; Doser, D. I.; Baker, M. R.; Kaip, G. M.; Eslick, B.

    2009-12-01

    We have collected over 580 gravity observations across the central Kenai Peninsula to better determine the structural geometry of the Border Ranges fault system (BRFS). Gravity points had a minimum spacing of 0.5 km, with denser readings taken over several moraines in an effort to determine density variations in glacial units. We also collected eight hand samples of exposed bedrock units for laboratory analysis of density and have assembled a suite of density logs from petroleum wells to estimate density variations within the Cook Inlet basin. We have tied our results to previous gravity surveys conducted in the 1960’s to 1990’s. Our preliminary results of analysis of gravity using Nettleton’s reduction method give Cretaceous accreted rocks with densities of around 2.9 g/cc whereas the densities of Quaternary alluvial and glacial deposits of the forearc basin range from 1.63 to 2.41 g/cc. Our ultimate goal is to test several plausible models of structure along the Border Ranges fault system using a 3-D inversion scheme on gravity and magnetic data constrained with other geophysical, borehole and surface geological information.

  6. 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

  7. 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

  8. 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 the...

  9. 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 the...

  10. 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 the...

  11. 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 the...

  12. 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 the...

  13. Watershed influences on the structure and function of riparian wetlands associated with headwater streams - Kenai Peninsula, Alaska.

    PubMed

    Whigham, D F; Walker, C M; Maurer, J; King, R S; Hauser, W; Baird, S; Keuskamp, J A; Neale, P J

    2017-12-01

    Riparian wetlands are dynamic components of landscapes. Located between uplands and aquatic environments, riparian habitats intercept sediments and nutrients before they enter aquatic environments. They are a source of organic matter and nutrients to aquatic systems, and they provide important habitat for animals, often serving as corridors for the movement of animals between habitats in fragmented landscapes. In this project, we focused on the structure and function of riparian wetlands associated with headwater streams in Alaska that serve as nursery habitats for juvenile salmonids. We asked whether or not the structure and function of headwater wetlands differed between watersheds with and without nitrogen-fixing Alder (Alnus spp.). We found that the aboveground biomass of riparian vegetation was higher in the watershed with Alder, but the largest differences were in the litter layer and belowground where vegetation in the watershed with no Alder had significantly higher root biomass. Interstitial water chemistry also differed between the study sites with significantly higher inorganic N and significantly different characteristics of colored dissolved organic matter at the site with Alder on the watershed. The biomass of litter that hung over the creek bank was less at the site with Alder on the watershed and an in situ decomposition experiment showed significant differences between the two systems. Results of the research demonstrates that watershed characteristics can impact the ecology of headwater streams in ways that had not been previously recognized. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  14. 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.

  15. 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

  16. College Fjord, Prince Williams Sound

    NASA Image and Video Library

    2001-07-21

    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. http://photojournal.jpl.nasa.gov/catalog/PIA02664

  17. Cooperative Alaska Forest Inventory

    Treesearch

    Thomas Malone; Jingjing Liang; Edmond C. Packee

    2009-01-01

    The Cooperative Alaska Forest Inventory (CAFI) is a comprehensive database of boreal forest conditions and dynamics in Alaska. The CAFI consists of field-gathered information from numerous permanent sample plots distributed across interior and south-central Alaska including the Kenai Peninsula. The CAFI currently has 570 permanent sample plots on 190 sites...

  18. 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

    ..., Grand Creek, and Falls Creek on the Kenai Peninsula, near the community of Moose Pass, Alaska. The...: 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...

  19. Climate change vulnerability assessment for the Chugach National Forest and the Kenai Peninsula

    Treesearch

    Gregory H. Hayward; Steve Colt; Monica L. McTeague; Teresa N. Hollingsworth

    2017-01-01

    This assessment evaluates the effects of future climate change on a select set of ecological systems and ecosystem services in Alaska’s Kenai Peninsula and Chugach National Forest regions. The focus of the assessment was established during a multi-agency/organization workshop that established the goal to conduct a rigorous evaluation of a limited range of topics rather...

  20. Northern highbush and half-high blueberries on the Alaskan Kenai peninsula:preliminary observations

    USDA-ARS?s Scientific Manuscript database

    Home and commercial cultivation of small fruits is popular in Alaska and blueberries of several species, such as V. corymbosum and V. angustifolium, have potential as cultivated crops for local production. In June 2009, we established blueberry plantings in two locations on the Kenai Peninsula, appr...

  1. The western Kenai Peninsula: An opportunity to study fire and its effects on soils and trees

    Treesearch

    Theresa Jain; Tara M. Barrett

    2011-01-01

    Most of the coastal Alaska inventory unit is part of the temperate rain-forest biome, and fire is an extremely rare event. However, for the western side of the Kenai Peninsula and the Cook Inlet region, fire is a common source of natural disturbance (fig. 50). Although wildfires are a normal part of the disturbance regime for this region, urban growth and associated...

  2. Fjord Delta Modification by a Massive Landslide Tsunami in Taan Fjord, AK

    NASA Astrophysics Data System (ADS)

    Bloom, C. K.; MacInnes, B. T.; Higman, B. M.; Richmond, B. M.

    2016-12-01

    On October 17th, 2015 a landslide adjacent to the tidewater Tyndall Glacier, located at the head of Taan Fjord in Alaska's Icy Bay, generated a massive tsunami that inundated and modified several large stream deltas within the fjord. Initial estimates of the maximum tsunami run up were as high as 150 m using the Alaska IfSAR-derived DEM. Before and after imagery from Landsat and GeoEye showed extensive vegetation loss up to 100 m elevation in places with indications that sediment had been redistributed or eroded from the deltas and delta fronts in Taan Fjord. The frequency of landslide tsunamis around the globe is poorly understood and identifying characteristic delta features in locations like Taan Fjord may reveal evidence of past events elsewhere. In the spring and summer of 2016 an interdisciplinary group of scientists travelled to Taan Fjord to conduct a post-tsunami survey that confirmed runup as high as 190 m and characterized the geomorphology and sedimentology of the fjord deltas using a combination of traditional and non-traditional methods. To characterize the sedimentology of tsunami deposits from this event, we dug individual trenches and trench transects on four deltas within Taan Fjord. The trenches revealed a relatively consistent stratigraphy on deltas both close to, and several kilometers from, the tsunami source. Ground penetrating radar surveys were completed between points on two transects to correlate and trace deposits between trenches. Several layers of poorly-sorted silt-starved sediment overlay a clearly identifiable substrate containing plant roots. To capture a detailed three-dimensional picture of geomorphic features on the deltas, pole-mounted and handheld structure-from-motion (SfM) surveys were conducted. Comparison of the SfM data to detailed topography of nearby unaffected deltas reveals characteristic dissimilarities between a typical fjord delta and a tsunami-inundated delta.

  3. 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

  4. 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

  5. Reliability of a fjord glacier's fluctuations for paleoclimatic reconstructions

    NASA Astrophysics Data System (ADS)

    Mann, Daniel H.

    1986-01-01

    Historical observations of fjord glaciers in southern Alaska suggest that their fluctuations may be asynchronous with one another and with climate. Possible causes for anomalous fjord glacier response to climatic changes involve the instabilities inherent in a calving terminus, the interaction of fjord geometry with the extent of the calving terminus, and the intersection of low-lying snow line by a thickening glacier. The Lituya glacier system in southeast Alaska is analyzed with reference to these phenomena to test the reliability of its Holocene glacial deposits as paleoclimatic records. This fjord glacier is shown to have been probably free of major, nonclimatic responses during the Holocene except for an insensitive period of up to 1000 yr that followed calving retreats. The insensitive period has no functional effect on how the relatively coarse geologic record is interpreted in terms of paleoclimate. However, it makes impossible any inference of climatic trends from this glacier's behavior in historical times. Fjord glacier deposits can be dependable records of paleoclimate but each glacier requires careful scrutiny. Anomalous glacier responses to climate are most likely to occur in fjords of complex geometry, in regions of relatively low snow line, and where glaciers terminate at fjord mouths bordering the open sea.

  6. 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.

  7. Unusually loud ambient noise in tidewater glacier fjords: A signal of ice melt

    NASA Astrophysics Data System (ADS)

    Pettit, Erin Christine; Lee, Kevin Michael; Brann, Joel Palmer; Nystuen, Jeffrey Aaron; Wilson, Preston Scot; O'Neel, Shad

    2015-04-01

    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 nonglacierized fjords). Icy Bay, Alaska, has an annual average sound pressure level of 120 dB (referenced to 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.

  8. 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.

  9. 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.

  10. Studies in the wilderness areas of the Kenai National Wildlife Refuge: fire, bark beetles, human development, and climate change

    Treesearch

    Edward E. Berg

    2000-01-01

    Wilderness areas comprise 65% of the 1.92 million acre Kenai National Wildlife Refuge, Alaska. Fire history studies indicate that fire frequency increased substantially in both white and black spruce forests after European settlement. Dendrochronolgy studies indicate that regional-scale spruce bark beetle outbreaks occurred in the 1820s, 1880s, and 1970s. None of these...

  11. 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.

  12. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this spectacular MODIS image from November 7, 2001, the skies are clear over Alaska, revealing winter's advance. Perhaps the most interesting feature of the image is in its center; in blue against the rugged white backdrop of the Alaska Range, Denali, or Mt. McKinley, casts its massive shadow in the fading daylight. At 20,322 ft (6,194m), Denali is the highest point in North America. South of Denali, Cook Inlet appears flooded with sediment, turning the waters a muddy brown. To the east, where the Chugach Mountains meet the Gulf of Alaska, and to the west, across the Aleutian Range of the Alaska Peninsula, the bright blue and green swirls indicate populations of microscopic marine plants called phytoplankton.

  13. Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this spectacular MODIS image from November 7, 2001, the skies are clear over Alaska, revealing winter's advance. Perhaps the most interesting feature of the image is in its center; in blue against the rugged white backdrop of the Alaska Range, Denali, or Mt. McKinley, casts its massive shadow in the fading daylight. At 20,322 ft (6,194m), Denali is the highest point in North America. South of Denali, Cook Inlet appears flooded with sediment, turning the waters a muddy brown. To the east, where the Chugach Mountains meet the Gulf of Alaska, and to the west, across the Aleutian Range of the Alaska Peninsula, the bright blue and green swirls indicate populations of microscopic marine plants called phytoplankton. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  14. A bayesian hierarchical model for spatio-temporal prediction and uncertainty assessment using repeat LiDAR acquisitions for the Kenai Peninsula, AK, USA

    Treesearch

    Chad Babcock; Hans Andersen; Andrew O. Finley; Bruce D. Cook

    2015-01-01

    Models leveraging repeat LiDAR and field collection campaigns may be one possible mechanism to monitor carbon flux in remote forested regions. Here, we look to the spatio-temporally data-rich Kenai Peninsula in Alaska, USA to examine the potential for Bayesian spatio-temporal mapping of terrestrial forest carbon storage and uncertainty.

  15. Organic carbon fluxes in fjords across a high-to-mid latitudinal gradient

    NASA Astrophysics Data System (ADS)

    Cui, X.; Bianchi, T. S.; Jaeger, J. M.; Savage, C.; Smith, R. W.

    2016-12-01

    Over geological timescales, the net burial of biospheric OC (OCbio) and oxidation of petrogenic OC (OCpetro) are important processes influencing atmospheric CO2 levels. Coastal sediments are major depo-centers that account for as much as 90% of Holocene OC burial in the global ocean. Fjords, as a major component of coastal systems, are deep, glacially-carved estuaries located in high latitudes and are key in connecting rivers and the ocean. These systems have recently been identified as sites of enhanced organic carbon burial with surface area-normalized OC burial rates at least five times greater than other marine systems. Recent studies proposed that fjords also have an impact on atmospheric CO2 levels over glacial-interglacial time. Understanding sediment processes, sources and respective burial of different types of OC are necessary to better constrain OC burial in fjords, particularly fjords across glaciated versus non-glaciated systems across latitudinal gradients. Here, we use surface sediment samples from multiple fjords to quantify the sources and burial of OC and conduct a latitudinal comparison across a suite of fjords. A multi-proxy approach (stable isotopes, radiocarbon, lignin-phenols and lipids) allow for separation of marine and terrestrial OCbio, and OCpetro in surface sediments. 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. These findings make SE Alaska potentially the largest sink of OCpetro in North America and a hotspot in burying marine OC (OCbio-mari). In contrast, sedimentary OC in fjords along Fiordland, New Zealand is dominated by vascular plants sources, with increasing OCbio-mari inputs along the inner-to-outer fjord transects. Interestingly, there is minimal OCpetro contribution to fjords in this region. We conclude that there may be a general

  16. Alaska

    SciTech Connect

    Jones, B.C.; Sears, D.W.

    1981-10-01

    Twenty-five exploratory wells were drilled in Alaska in 1980. Five oil or gas discovery wells were drilled on the North Slope. One hundred and seventeen development and service wells were drilled and completed, primarily in the Prudhoe Bay and Kuparuk River fields on the North Slope. Geologic-geophysical field activity consisted of 115.74 crew months, an increase of almost 50% compared to 1979. These increases affected most of the major basins of the state as industry stepped up preparations for future lease sales. Federal acreage under lease increased slightly, while state lease acreage showed a slight decline. The year's oil production showed a increase of 16%, while gas production was down slightly. The federal land freeze in Alaska showed signs of thawing, as the US Department of Interior asked industry to identify areas of interest onshore for possible future leasing. National Petroleum Reserve in Alaska was opened to private exploration, and petroleum potential of the Arctic Wildlife Refuge will be studied. One outer continental shelf lease sale was held in the eastern Gulf of Alaska, and a series of state and federal lease sales were announced for the next 5 years. 5 figures, 5 tables.

  17. Bathymetry of Greenland Fjords

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Operation IceBridge (OIB) has performed extensive airborne gravity surveys of Greenlandic fjords in order to model their bathymetry. Bathymetry inversions from gravity data provide a model of the fjord bathymetry in areas that are otherwise difficult to survey. We use these gravity surveys along with other OIB datasets to create bathymetry models for fjords surveyed by OIB from 2009-2012. These models allow us to estimate depths to the grounding line in areas with poor radar returns and sill depths and overdeepenings in the fjords. Models have been constructed by combining ice-surface and ice-thickness data from coincident OIB lidar and radar surveys. The inversion of gravity anomalies to bathymetry models is dependent on assumptions of both local and regional variations in geology. Local variations can often be identified with OIB magnetic anomalies. Regional geoid variations produce long-wavelength gravity anomalies that are part of the observed gravity, but not present in the forward modeled gravity over the known bed. This effect varies in magnitude around Greenland. In long fjords, removing the long-wavelength components of the observed anomalies reduces the uncertainties from regional geological variations. The average combined error for absolute model depths varies regionally between 50 m and 200 m. The error budget takes into account the measurement uncertainty of the gravity survey along with sensitivity of the model to regional gravity corrections and the point at which the model is pinned to known bed. Gravity inversions model bathymetry at ~5 km wavelengths, while bed topography onshore is known at a higher resolution from radar surveys. This change of length scale must be taken into account when using bathymetry models to consider grounding line morphology as well as when combining modeled bathymetry with offshore bathymetric data. Models can be improved by pinning to ship surveys of offshore bathymetry. Our dataset has incorporated available offshore

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. Temporal variability of benthic communities in an Alaskan glacial fjord, 1971-2007.

    PubMed

    Blanchard, Arny L; Feder, Howard M; Hoberg, Max K

    2010-03-01

    Temporal trends of deep-subtidal macrofauna in Port Valdez, Alaska, were assessed with respect to multiple environmental stressors. Effects from a magnitude 9.2 earthquake in Prince William Sound, Alaska, 1964, were reflected in recolonization of the basin of the fjord, increased abundance and number of taxa over time, and moderately increased variability in abundance through 1990, stabilizing 26years after the earthquake. Long-term climatic variability and local physical processes were important sources of spatial and temporal variability. Correlative evidence suggests that indirect effects of juvenile salmon from a shoreline salmon hatchery and deposition of adult salmon carcasses moderately enhanced deep-basin benthic communities. Effects on the deep benthos from a marine oil terminal were negligible. Overall, faunal trends deviated from the stability expected for benthic communities in other fjords. Physical characteristics of the fjord were important in mediating the effects of stressors and in delaying the readjustment process.

  6. Stream habitat assessment project: Prince William Sound and lower Kenai Peninsula. Restoration project 93051. Exxon Valdez oil spill restoration project final report

    SciTech Connect

    Sundet, K.; Kuwada, M.N.; Barnhart, J.

    1994-04-01

    The Alaska Department of Fish and Game, Habitat and Restoration Division, conducted surveys of anadromous fish streams in Prince William Sound and Lower Kenai Peninsula from August 2 to September 23, 1993. These surveys focused on Chenega, Eyak and Tatilek corporation lands and Chugach Alaska Corporation lands in Prince William Sound, and on Port Graham and English Bay corporation lands on the lower Kenai Peninsula in order to document anadromous fish distribution and habitat on private lands throughout the spill area. 180 new anadromous fish streams were documented totalling approximately 57 km (35 miles). Pink and coho salmon were the principal fish species found, followed by chum salmon, sockeye salmon, Dolly Varden, rainbow trout, cutthroat trout, stickleback and sculpin, and in intertidal channels, juvenile founder.

  7. 33 CFR 162.245 - Kenai River, Kenai, Alaska; use, administration, and navigation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... centerline of the city dock and extending about 2,200 feet upstream to a point 200 feet upstream from the Inlet Co. dock. (b) The regulations. (1) Vessels may navigate, anchor, or moor within the area until...

  8. Trace elements reconnaissance in the Jakolof Bay area, southern Alaska

    USGS Publications Warehouse

    Moxham, Robert M.; Nelson, Arthur E.

    1950-01-01

    As a result of inquiries by prospectors in 1948 concerning radioactive ores in the vicinity of Jakolof Bay on the Kenai Peninsula in southern Alaska, the Geological Survey conducted a brief investigation during 1949. No radioactive material was found. Possibly a chromite stockpile in this locality was mistaken for pitchblende.

  9. Geoengineering Glacial Fjords

    NASA Astrophysics Data System (ADS)

    Wolovick, M.; Sergienko, O. V.

    2016-12-01

    Mass loss from Greenland and Antarctica is highly sensitive to the presence of warm ocean water that drives melting of ice shelves and marine terminated glaciers. This warm water resides offshore at depth and accesses the ice-shelf cavities and glacier fjords through deep but narrow troughs carved across the continental shelf. Here, we investigate the possibility of blocking warm water transport through these choke points with an artificial sill. Using a simple width-averaged model of ice stream flow coupled to a melt-driven plume flow, we find that grounding line retreat and sea level rise can be delayed (or potentially reversed depending on glacier geometries) for hundreds of years if warm water is prevented from accessing outlet glaciers and ice-shelf cavities. In our simulations, glaciers with a floating tongue exhibit a strong response to the presence of the artificial sill; while the response of glaciers without a floating tongue depends on the choice of calving law. We conclude by comparing the scale of the artificial sills with the scale of other large public works projects.

  10. 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...

  11. 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...

  12. 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...

  13. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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...

  14. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Hypoxia in Chilean Patagonian Fjords

    NASA Astrophysics Data System (ADS)

    Silva, Nelson; Vargas, Cristian A.

    2014-12-01

    Chilean Patagonia is one of the largest estuarine systems in the world. It is characterized by a complex geography of approximately 3300 islands, a total surface area of 240,000 km2, and 84,000 km of coast line, including islands, peninsulas, channels, fjords, and sounds. The Chilean Patagonia Interior Sea is filled with a mixture of sea, estuarine, and fresh waters, and is characterized by a two layer vertical general circulation. Dissolved oxygen (DO) conditions in these fjords were analyzed based on historic salinity, dissolved oxygen and nutrient data from 1200 oceanographic stations. Horizontal advection of adjacent well oxygenated Subantarctic Waters (5-6 mL L-1) was the mayor source of DO in the deep layers of the Interior Sea. Incoming DO was consumed by the respiration of autochthonous and allochthonous particulate organic matter, as ocean water flows towards the continental fjord heads, reaching near-hypoxic (2-3 mL L-1) or hypoxic levels (<2 mL L-1). As DO declined nutrient concentrations increased towards the fjord heads (from ∼1.6 μM PO4-3 and ∼16 μM NO3- to ∼2.4 μM PO4-3 and ∼24 μM NO3-). Overall, DO conditions in the Interior Sea were mostly the result of a combination of physical and biogeochemical processes. In all eastern channels and fjords, a low DO zone developed near the fjord heads (<4 mL L-1) as a result of larger allochthonous particulate organic matter inputs transported by local rivers. This enhanced organic matter input to the deep layer increased DO consumption due to respiration and overwhelmed the oxygen supplied by horizontal advection. Out of the 90 Chilean Patagonian gulfs, channels and fjords analyzed, 86 systems were oxic (>2 mL L-1) and four hypoxic (<2 mL L-1), but only at their heads. None were found to be anoxic (0 mL L-1). We found these DO conditions to be permanent features of the Chilean Patagonia Interior Sea.

  1. 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.

  2. 78 FR 15669 - Marine Mammals: Alaska Harbor Seal Habitats

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-12

    ... habitats are only available to seals in south-central and southeast Alaska. Tidewater glacier areas serve... seal abundance has significantly declined in two glacial fjords: Glacier Bay in southeast Alaska and... to seals (Jansen et al. 2010b). In 2012, at Glacier Bay-- where cruise ship approaches to seals...

  3. Ocean-Glacier Interactions in Alaska and Comparison to Greenland

    NASA Astrophysics Data System (ADS)

    Motyka, R. J.; Truffer, M.

    2011-12-01

    Meltwater from Alaska's coastal glaciers and icefields accounts for nearly half of the total freshwater discharged into the Gulf of Alaska (GOA), with 10% coming from glacier volume loss associated with rapid thinning and retreat of glaciers (Neal et al, 2010). This glacier freshwater discharge contributes to maintaining the Alaska Coastal Current (ACC), which eventually reaches the Arctic Ocean (Royer and Grosch, 2006), thereby linking changes of glaciers along the coast of Alaska to the whole Arctic system. Water column temperatures on the shelf of northern GOA, monitored at buoy GAK1 near Seward, have increased by about 1 deg C since 1970 throughout the 250 m depth and vertical density stratification has also increased. Roughly half of the glacier contribution to ACC is derived from the ~ 50 tidewater glaciers (TWG) that drain from Alaska's coastal mountains into the Gulf of Alaska (GOA). Fjord systems link these TWGs to the GOA, with fjord circulation patterns driven in part by buoyancy-driven convection of subglacial freshwater discharge at the head of the fjord. Neoglacial shallow sills (< 50 m deep) modulate the influx of warm ocean waters (up to 10 deg C) into these fjords. Convection of these warm waters melts icebergs and submerged faces of TWGs. The study of interactions between glaciers, fjords, and the ocean in coastal Alaska has had a long but very sporadic history. We examine this record starting with the "TWG cycle" hypothesis. We next examine recent hydrographic data from several different TWG fjords, representative of advancing and retreating TWGs (Columbia, Yahtse, Hubbard, and LeConte Glaciers), evaluate similarities and differences, and estimate the relative contributions of submarine glacier melting and subglacial discharge to fjord circulation. Circulation of warm ocean waters in fjords has also been hypothesized to play an important role in destabilizing and modulating glacier discharge from outlet glaciers in Greenland. We therefore compare

  4. 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,…

  5. Modeling Spitsbergen fjords by hydrodynamic MIKE engine.

    NASA Astrophysics Data System (ADS)

    Kosecki, Szymon; Przyborska, Anna; Jakacki, Jaromir

    2013-04-01

    Two Svalbard's fjords - Hornsund (on the western side of the most southern part of Spitsbergen island) and Kongsfjorden (also on the western side of Spitsbergen island, but in the northern part) are quite different - the first one is "cold" and second one is "warm". It is obvious that both of them are under influence of West Spitsbergen Current (WSC), which curry out warm Atlantic water and cold East Spitsbergen Current detaches Hornsund. But there is also freshwater stored in Spitsbergen glaciers that have strong influence on local hydrology and physical fjord conditions. Both, local and shelf conditions have impact on state of the fjord and there is no answer which one is the most important in each fjord. Modeling could help to solve this problem - MIKE 3D model has been implemented for both fjords. Mesh-grid of the each fjord has been extended for covering shelf area. External forces like tides, velocities at the boundary and atmospheric forces together with sources of cold and dens fresh water in the fjords will give reliable representation of physical conditions in Hornsund and Kongsfjorden. Calculations of balances between cold fresh water and warm and salt will provide additional information that could help to answer the main question of the GAME (Growing of the Arctic Marine Ecosystem) project - what is the reaction of physically controlled Arctic marine ecosystem to temperature rise.

  6. Generating synthetic fjord bathymetry for coastal Greenland

    NASA Astrophysics Data System (ADS)

    Williams, Christopher N.; Cornford, Stephen L.; Jordan, Thomas M.; Dowdeswell, Julian A.; Siegert, Martin J.; Clark, Christopher D.; Swift, Darrel A.; Sole, Andrew; Fenty, Ian; Bamber, Jonathan L.

    2017-02-01

    Bed topography is a critical boundary for the numerical modelling of ice sheets and ice-ocean interactions. A persistent issue with existing topography products for the bed of the Greenland Ice Sheet and surrounding sea floor is the poor representation of coastal bathymetry, especially in regions of floating ice and near the grounding line. Sparse data coverage, and the resultant coarse resolution at the ice-ocean boundary, poses issues in our ability to model ice flow advance and retreat from the present position. In addition, as fjord bathymetry is known to exert strong control on ocean circulation and ice-ocean forcing, the lack of bed data leads to an inability to model these processes adequately. Since the release of the last complete Greenland bed topography-bathymetry product, new observational bathymetry data have become available. These data can be used to constrain bathymetry, but many fjords remain completely unsampled and therefore poorly resolved. Here, as part of the development of the next generation of Greenland bed topography products, we present a new method for constraining the bathymetry of fjord systems in regions where data coverage is sparse. For these cases, we generate synthetic fjord geometries using a method conditioned by surveys of terrestrial glacial valleys as well as existing sinuous feature interpolation schemes. Our approach enables the capture of the general bathymetry profile of a fjord in north-west Greenland close to Cape York, when compared to observational data. We validate our synthetic approach by demonstrating reduced overestimation of depths compared to past attempts to constrain fjord bathymetry. We also present an analysis of the spectral characteristics of fjord centrelines using recently acquired bathymetric observations, demonstrating how a stochastic model of fjord bathymetry could be parameterised and used to create different realisations.

  7. 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.

  8. 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.

  9. Slow deglaciation of north Spitsbergen fjords

    NASA Astrophysics Data System (ADS)

    Før Gjermundsen, Endre; Forwick, Matthias; Briner, Jason P.; Akçar, Naki; Janson, Maximillian; Kubik, Peter; Hormes, Anne

    2014-05-01

    Outlet glaciers draining ice sheets are systems with complex internal dynamics and velocity variations, and their responses to climate change are still not fully understood so that it remains difficult to predict future responses of ice sheets to climate change and sea-level rise. However, increased knowledge of the behavior of outlet glaciers draining past ice sheets may provide a valuable tool to improve our predictive ability. In our study, we performed 10Be analyses of erratic boulders and bedrock from different elevations along a 70 km long transect in the Austfjorden/Wijdefjorden fjord system, the largest fjord system on northern Svalbard that acted as pathway for an ice stream draining the last Svalbard Barents Sea Ice Sheet (SBSIS) towards the Arctic Ocean. Our data suggest a relatively slow fjord deglaciation lasting between 23 and 11 ka which is in contrast to the much more rapid deglaciation of fjords recently documented elsewhere at the transition of the Late Weichelian and Holocene. The 10Be results also provide new constrain on ice sheet thickness in this part of the SBSIS. Integration with swath-bathymetry data suggests that this slow deglaciation of the study area was most probably controlled by the generally shallow water depths in the fjord, limiting calving-induced rapid ice retreat.

  10. A fjord-glacier coupled system model

    NASA Astrophysics Data System (ADS)

    de Andrés, Eva; Otero, Jaime; Navarro, Francisco; Prominska, Agnieszka; Lapazaran, Javier; Walczowski, Waldemar

    2017-04-01

    With the aim of studying the processes occurring at the front of marine-terminating glaciers, we couple a fjord circulation model with a flowline glacier dynamics model, with subglacial discharge and calving, which allows the calculation of submarine melt and its influence on calving processes. For ocean modelling, we use a general circulation model, MITgcm, to simulate water circulation driven by both fjord conditions and subglacial discharge, and for calculating submarine melt rates at the glacier front. To constrain freshwater input to the fjord, we use estimations from European Arctic Reanalysis (EAR). To determine the optimal values for each run period, we perform a sensitivity analysis of the model to subglacial discharge variability, aimed to get the best fit of model results to observed temperature and salinity profiles in the fjord for each of these periods. Then, we establish initial and boundary fjord conditions, which we vary weekly-fortnightly, and calculate the submarine melt rate as a function of depth at the calving front. These data are entered into the glacier-flow model, Elmer/Ice, which has been added a crevasse-depth calving model, to estimate the glacier terminus position at a weekly time resolution. We focus our study on the Hansbreen Glacier-Hansbukta Fjord system, in Southern Spitsbergen, Svalbard, where a large set of data are available for both glacier and fjord. The bathymetry of the entire system has been determined from ground penetrating radar and sonar data. In the fjord we have got temperature and salinity data from CTDs (May to September, 2010-2014) and from a mooring (September to May, 2011-2012). For Hansbreen, we use glacier surface topography data from the SPIRIT DEM, surface mass balance from EAR, centre line glacier velocities from stake measurements (May 2005-April 2011), weekly terminus positions from time-lapse photos (Sept. 2009-Sept. 2011), and sea-ice concentrations from time-lapse photos and Nimbus-7 SMMR and DMSP SSM

  11. Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK

    USGS Publications Warehouse

    Love, Katherine B; Hallet, Bernard; Pratt, Thomas L.; O'Neel, Shad

    2016-01-01

    To explore links between glacier dynamics, sediment yields and the accumulation of glacial sediments in a temperate setting, we use extensive glaciological observations for Columbia Glacier, Alaska, and new oceanographic data from the fjord exposed during its retreat. High-resolution seismic data indicate that 3.2 × 108 m3 of sediment has accumulated in Columbia Fjord over the past three decades, which corresponds to ~5 mm a−1 of erosion averaged over the glaciated area. We develop a general model to infer the sediment-flux history from the glacier that is compatible with the observed retreat history, and the thickness and architecture of the fjord sediment deposits. Results reveal a fivefold increase in sediment flux from 1997 to 2000, which is not correlated with concurrent changes in ice flux or retreat rate. We suggest the flux increase resulted from an increase in the sediment transport capacity of the subglacial hydraulic system due to the retreat-related steepening of the glacier surface over a known subglacial deep basin. Because variations in subglacial sediment storage can impact glacial sediment flux, in addition to changes in climate, erosion rate and glacier dynamics, the interpretation of climatic changes based on the sediment record is more complex than generally assumed.

  12. 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.

  13. 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.

  14. Quantification and Analysis of Icebergs in a Tidewater Glacier Fjord Using an Object-Based Approach.

    PubMed

    McNabb, Robert W; Womble, Jamie N; Prakash, Anupma; Gens, Rudiger; Haselwimmer, Christian E

    2016-01-01

    Tidewater glaciers are glaciers that terminate in, and calve icebergs into, the ocean. In addition to the influence that tidewater glaciers have on physical and chemical oceanography, floating icebergs serve as habitat for marine animals such as harbor seals (Phoca vitulina richardii). The availability and spatial distribution of glacier ice in the fjords is likely a key environmental variable that influences the abundance and distribution of selected marine mammals; however, the amount of ice and the fine-scale characteristics of ice in fjords have not been systematically quantified. Given the predicted changes in glacier habitat, there is a need for the development of methods that could be broadly applied to quantify changes in available ice habitat in tidewater glacier fjords. We present a case study to describe a novel method that uses object-based image analysis (OBIA) to classify floating glacier ice in a tidewater glacier fjord from high-resolution aerial digital imagery. Our objectives were to (i) develop workflows and rule sets to classify high spatial resolution airborne imagery of floating glacier ice; (ii) quantify the amount and fine-scale characteristics of floating glacier ice; (iii) and develop processes for automating the object-based analysis of floating glacier ice for large number of images from a representative survey day during June 2007 in Johns Hopkins Inlet (JHI), a tidewater glacier fjord in Glacier Bay National Park, southeastern Alaska. On 18 June 2007, JHI was comprised of brash ice ([Formula: see text] = 45.2%, SD = 41.5%), water ([Formula: see text] = 52.7%, SD = 42.3%), and icebergs ([Formula: see text] = 2.1%, SD = 1.4%). Average iceberg size per scene was 5.7 m2 (SD = 2.6 m2). We estimate the total area (± uncertainty) of iceberg habitat in the fjord to be 455,400 ± 123,000 m2. The method works well for classifying icebergs across scenes (classification accuracy of 75.6%); the largest classification errors occur in areas with

  15. Quantification and Analysis of Icebergs in a Tidewater Glacier Fjord Using an Object-Based Approach

    PubMed Central

    McNabb, Robert W.; Womble, Jamie N.; Prakash, Anupma; Gens, Rudiger; Haselwimmer, Christian E.

    2016-01-01

    Tidewater glaciers are glaciers that terminate in, and calve icebergs into, the ocean. In addition to the influence that tidewater glaciers have on physical and chemical oceanography, floating icebergs serve as habitat for marine animals such as harbor seals (Phoca vitulina richardii). The availability and spatial distribution of glacier ice in the fjords is likely a key environmental variable that influences the abundance and distribution of selected marine mammals; however, the amount of ice and the fine-scale characteristics of ice in fjords have not been systematically quantified. Given the predicted changes in glacier habitat, there is a need for the development of methods that could be broadly applied to quantify changes in available ice habitat in tidewater glacier fjords. We present a case study to describe a novel method that uses object-based image analysis (OBIA) to classify floating glacier ice in a tidewater glacier fjord from high-resolution aerial digital imagery. Our objectives were to (i) develop workflows and rule sets to classify high spatial resolution airborne imagery of floating glacier ice; (ii) quantify the amount and fine-scale characteristics of floating glacier ice; (iii) and develop processes for automating the object-based analysis of floating glacier ice for large number of images from a representative survey day during June 2007 in Johns Hopkins Inlet (JHI), a tidewater glacier fjord in Glacier Bay National Park, southeastern Alaska. On 18 June 2007, JHI was comprised of brash ice (x¯ = 45.2%, SD = 41.5%), water (x¯ = 52.7%, SD = 42.3%), and icebergs (x¯ = 2.1%, SD = 1.4%). Average iceberg size per scene was 5.7 m2 (SD = 2.6 m2). We estimate the total area (± uncertainty) of iceberg habitat in the fjord to be 455,400 ± 123,000 m2. The method works well for classifying icebergs across scenes (classification accuracy of 75.6%); the largest classification errors occur in areas with densely-packed ice, low contrast between

  16. 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.

  17. Glacimarine Sedimentary Processes and Deposits at Fjord-Terminating Tidewater Glacier Margins

    NASA Astrophysics Data System (ADS)

    Streuff, K.; O'Cofaigh, C.; Lloyd, J. M.; Noormets, R.; Nielsen, T.; Kuijpers, A.

    2016-12-01

    Many fjords along Arctic coasts are influenced by tidewater glaciers, some of them fast-flowing ice sheet outlets. Such glaciers provide important links between terrestrial and marine environments, and, due to their susceptibility to climatic and oceanographic changes, have undergone a complex history of advance and retreat since the last glacial maximum (LGM). Although a growing body of evidence has led to a better understanding of the deglacial dynamics of individual glaciers since the LGM, their overall Holocene glacimarine processes and associated sedimentary and geomorphological products often remain poorly understood. This study addresses this through a detailed analysis of sediment cores, swath bathymetric and sub-bottom profiler data collected from seven fjords in Spitsbergen and west Greenland. The sediment cores preserve a complex set of lithofacies, which include laminated and massive muds in ice-proximal, and bioturbated mud in more ice-distal settings, diamicton in iceberg-dominated areas and massive sand occurring as lenses, laminae and thick beds. These facies record the interplay of three main glacimarine processes, suspension settling, iceberg rafting and sediment gravity flows, and collectively emphasise the dominance of glacial meltwater delivery to sedimentation in high Arctic fjords. The seafloor geomorphology in the fjords shows a range of landforms that include glacial lineations associated with fast ice-flow, terminal moraines and debris lobes marking former maximum glacier extents, and small transverse moraines formed during deglaciation by glaciotectonic deformation at the grounding line and crevasse-squeezing. Additional landforms such as iceberg ploughmarks, submarine channels, pockmarks, and debris lobes formed during or after deglaciation by iceberg calving, erosion by meltwater, and sediment reworking. We present here a new model for sedimentary and geomorphological processes in front of contemporary tidewater glaciers, which

  18. 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.

  19. Renouvellement des eaux du fjord du Saguenay

    NASA Astrophysics Data System (ADS)

    Belzile, Melany

    Le fjord du Saguenay, localise dans la region subarctique de l'est du Canada, ala particularite d' etre connecte a un estuaire tres energetique plutot que directement a 1' ocean. L'embouchure du fjord est situee ala rencontre d'un chenal profond et d'un seuil de 20m de profondeur qui limite les echanges d'eau entre le fjord et l'estuaire du Saint-Laurent. Cependant, les grandes amplitudes de maree a son embouchure ont le potentiel d'entrainer des eaux denses du Saint-Laurent a l'interieur du fjord renouvelant ainsi les eaux des differents bassins. Dans le but d' a voir une meilleure comprehension de la dynamique et de la saisonnalite des renouvellements dans le bassin interne, deux mouillages y ont ete deployes pour recolter les premieres donnees de courant, sur toute la colonne d' eau et sur plusieurs mois, ainsi que des observations de temperature et de salinite a differentes profondeurs. L'un de ces mouillages n' a malheureusement pas pu etre analyse en detail dfi a la complexite de ses resultats et au manque de temps. Des profils ont ete recoltes le long de section transversales (transects), couvrant plusieurs saisons et plusieurs annees, ce qui a contribue a une meilleure comprehension de la distribution spatiale des masses d'eau dans le fjord. Les resultats montrent que ladynamique du fjord est plus complexe que ce qui avait ete precedemment presente dans la litterature. Un changement saisonnier abrupte dans la circulation du fjord a ete observe a la rni-fevrier. De plus, des renouvellements non-anticipes juste en-dessous de la thermohalocline (˜ 10 m de profondeur) ont ete observes entre la fin de 1' hiver et le milieu de 1' ete. En fonction des saisons, trois types de renouvellement peuvent etre observes : renouvellements profonds a l'automne et au debut de l'hiver suivis des renouvellements de sous-surface et enfin les renouvellements a des profondeurs intermediaires pendant l'ete. Le changement saisonnier abrupte observe au milieu de l'hiver ainsi que la

  20. Deep ventilation process in Patagonian fjord, Chile

    NASA Astrophysics Data System (ADS)

    Pérez-Santos, Iván; Silvan, Nelson; Castillo, Manuel; Mayorga, Nicolas; Schneider, Wolfgang; Montero, Paulina; Daneri, Giovanni; Valle-Levinson, Arnoldo; Pizarro, Oscar; Ramirez, Nadín; Igor, Gabriela; Navarro, Eduardo

    2017-04-01

    The Puyuhuapi Fjord (44.6° S) has previously been reported as one of the hypoxic fjords in Chilean Patagonia (dissolved oxygen -DO below 2 mL L-1). Hydrographic sampling between 1995-2016 confirmed hypoxia below 100 m depth, down to the bottom (250 m). A line of sensors at an oceanographic mooring in Puyuhuapi were deployed to continuously record the temporal-vertical behaviour of water column temperature and salinity from the surface down to 120 m, from February to July 2015. A multi-Parameter water quality sonde was deployed at the bottom of the line, with a DO optical sensor. From February to mid-May, hypoxia was sustained (1.4-1.6 mL L-1). However, from May until the end of June, DO values increased (2.8 mL L-1), exceeding the hypoxia threshold. This was the first event of deep ventilation reported in a Chilean Patagonian Fjord. During this time period, deep water temperatures increased by 1.3 °C, coinciding with the decreased in salinity from 33.6 to 32.8. The main cause of this event was attributed to the arrival of a new volume of mixed oceanic water into the fjord, transported by Modified Subantartic Water, with warm temperatures, lower salinities and slightly higher DO values, given its origin in the surface layer of the outer oceanic region. A new experiment was carried out during January-November, 2016 in order to corroborate the ventilation process and its connection with the adjacent ocean. Temperature, salinity and DO sensors were deployed in the outside fjords region close to the ocean (Melinka Channel) and in Puyuhuapi Fjord, to record the data at very high temporal resolution. The distance between both stations was 150 km. In the oceanic mooring the DO time series collected at 150 m depth showed hypoxia in summer related to the position of the Equatorial Sub-surface water, but from fall DO started to increase registering high values in August and September (4-5 mL/L) when the Subantartic Water arrive. The DO records in Puyuhuapi at 120 m showed a

  1. An Updated Geoid Model for the Alaskan Kenai Peninsular Region using Airborne Gravimetry and GOCE

    NASA Astrophysics Data System (ADS)

    Holmes, S. A.; Preaux, S. A.; Weil, C.; Li, X.; Childers, V. A.; Roman, D. R.

    2012-12-01

    The U.S. National Geodetic Survey [NGS] seeks to transition the United States and its territories to a geoid-based vertical height system. By 2020, NGS intends that all orthometric heights in the USA will be determined in the field by using a reliable national geoid model to transform from geodetic heights obtained from GPS. Through their Gravity for the Redefinition of the American Vertical Datum [GRAV-D] program, NGS is updating its terrestrial gravimetry holdings by flying new airborne gravity surveys over a large fraction of the USA and its territories. Also important are the latest satellite-based models from the GRACE and GOCE missions, which are expected to provide much of the long-wavelength structure of the geoid model. In this study, we examine the gravimetry from a 2008 airborne campaign over the region surrounding the Kenai Peninsula in Alaska. For the longer (n=2-250) wavelengths, three-way comparisons between satellite gravity models, EGM2008, and the airborne gravimetry, point to likely deficiencies in the EGM2008 geoid in this region. Supporting these analyses, inspection of the discrepancies between the airborne gravimetry and EGM2008 reveals that medium-scale (n=200-720) features defined across adjacent airborne tracks are geographically co-located with gaps in the terrestrial data which supported EGM2008. Lastly, we observe many areas in which the airborne gravimetry is validating much of the 'higher'-resolution information (n=720-1440) in EGM2008, thereby confirming the capability of this data type to contribute to geoid models in this spectral band. This is also the case in areas where EGM2008 is unsupported by terrestrial gravimetry, providing unexpectedly good agreement between the airborne gravimetry and Residual Terrain Models used for EGM2008.

  2. Ocean circulation and properties in Petermann Fjord, Greenland

    NASA Astrophysics Data System (ADS)

    Johnson, H. L.; Münchow, A.; Falkner, K. K.; Melling, H.

    2011-01-01

    The floating ice shelf of Petermann glacier interacts directly with the ocean and is thought to lose at least 80% of its mass through basal melting. Based on three opportunistic ocean surveys in Petermann Fjord we describe the basic oceanography: the circulation at the fjord mouth, the hydrographic structure beneath the ice shelf, the oceanic heat delivered to the under-ice cavity, and the fate of the resulting melt water. The 1100 m deep fjord is separated from neighboring Hall Basin by a sill between 350 and 450 m deep. Fjord bottom waters are renewed by episodic spillover at the sill of Atlantic water from the Arctic. Glacial melt water appears on the northeast side of the fjord at depths between 200 m and that of the glacier's grounding line (about 500 m). The fjord circulation is fundamentally three-dimensional; satellite imagery and geostrophic calculations suggest a cyclonic gyre within the fjord mouth, with outflow on the northeast side. Tidal flows are similar in magnitude to the geostrophic flow. The oceanic heat flux into the fjord appears more than sufficient to account for the observed rate of basal melting. Cold, low-salinity water originating in the surface layer of Nares Strait in winter intrudes far under the ice. This may limit basal melting to the inland half of the shelf. The melt rate and long-term stability of Petermann ice shelf may depend on regional sea ice cover and fjord geometry, in addition to the supply of oceanic heat entering the fjord.

  3. High-resolution seismic images of southeast Alaskan glacial fjords and continental shelf: Is the present the key to the past?

    NASA Astrophysics Data System (ADS)

    Gulick, S. P.; Willems, B.; Powell, R. D.; Jaeger, J. M.; Cowan, E. A.

    2005-12-01

    High-resolution seismic data collected aboard the R/V Maurice Ewing in August-September, 2004 imaged glacial fjords throughout southeast Alaska and the glacially- dominated shelf offshore the largest temperate glaciers in the world. Individual fjords show from 2-10 glacial advance-retreat sequences, whereas the high-resolution and deeper penetrating seismic data show the continental shelf records glacial advance and retreat sequences back to the onset of the Cordilleran Ice Sheet and earlier. Most sequences show erosional bases below a chaotic ice-contact seismic facies, a less chaotic ice-proximal facies, and a stratified ice-distal facies. Disenchantment Bay also shows flood events from the emptying of Russell Fjord following Hubbard Glacier ice-damming events. Sediment accumulation rates in Lisianski Inlet, Lynn Canal, Muir Inlet, Disenchantment Bay and the continental shelves offshore Icy Strait, Malaspina Glacier, and Bering Glacier are being examined based on clear seismic facies boundaries correlated with jumbo piston-cores from the upper sequence of each area. Although preliminary data are simple thicknesses rather than volumes, they suggest accumulation rates may vary by 2 orders of magnitude depending on over how many glacial cycles the rates are calculated. They confirm that glaciers are the dominant erosional agent because once glaciers have retreated from a fjord, accumulation rates dramatically decrease. Thus the variability likely results from differing glacial histories, lengths of glacial occupation and depths of erosion in individual fjords and different shelf regions. Limited age data suggest some fjords had Little Ice Age (LIA) advances whereas others may not have. Older advance-retreat sequences can include "Neoglacial" events and Last Glacial Maximum (LGM), and are locally preserved in a given fjord due to younger glacial erosional events not scouring to bedrock depths. Ages of these older sequences currently remain unconstrained. For example

  4. Seiche excitation in a highly stratified fjord of southern Chile: the Reloncaví fjord

    NASA Astrophysics Data System (ADS)

    Castillo, Manuel I.; Pizarro, Oscar; Ramírez, Nadin; Cáceres, Mario

    2017-02-01

    We describe a seiche process based on current, temperature, and sea-level data obtained from the Reloncaví fjord (41.6° S, 72.5° W) in southern Chile. We combined 4 months of acoustic Doppler current profiler (ADCP) data with sea-level, temperature, and wind time series to analyze the dynamics of low-frequency (periods > 1 day) internal oscillations in the fjord. Additionally, seasonal conductivity, temperature, and depth (CTD) data from 19 along-fjord stations were used to characterize the seasonality of the density field. The density profiles were used to estimate the internal long-wave phase speed (c) using two approximations: (1) a simple reduced gravity model (RGM) and (2) a continuously stratified model (CSM). No major seasonal changes in c were observed using either approximation (e.g., the CSM yielded 0.73 < c < 0.87 m s-1 for mode 1). The natural internal periods (TN) were estimated using Merian's formula for a simple fjord-like basin and the above phase speeds. Estimated values of TN varied between 2.9 and 3.5 days and were highly consistent with spectral peaks observed in the along-fjord currents and temperature time series. We conclude that these oscillations were forced by the wind stress, despite the moderate wind energy. Wind conditions at the end of winter gave us an excellent opportunity to explore the damping process. The observed damping time (Td) was relatively long (Td = 9.1 days).

  5. 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

  6. Flatfishes of Norwegian coasts and fjords

    NASA Astrophysics Data System (ADS)

    Albert, Ole Thomas; Eliassen, Jens-Eric; Høines, Åge

    1998-09-01

    Bottom trawl surveys in North Norwegian fjords and coastal areas, on a South Norwegian coastal bank, and along the Russian Kola coast, are used to describe distribution, species composition, individual growth, population structure, and exploitation of plaice ( Pleuronectes platessa), long rough dab ( Hippoglossoides platessoides), witch ( Glyptocephalus cynoglossus), lemon sole ( Microstomus kitt), dab ( Limanda limanda), megrim ( Lepidorhombus whiffiagonis), halibut ( Hippoglossus hippoglossus) and Greenland halibut ( Reinhardtius hippoglossoides). Based on distribution and abundance, individual species have been grouped as northern, southern or intermediate, as shallow or deep, and as associated with fjords or with coastal banks. The four most abundant flatfishes in Norwegian coastal zones, plaice, long rough dab, witch, and lemon sole, were equally or more abundant in the north compared to the south. Specimens of these species were generally larger in the north and mean length at age tended to be lower. Possible nursery areas were indicated for plaice and lemon sole.

  7. Zooplankton Distribution in Four Western Norwegian Fjords

    NASA Astrophysics Data System (ADS)

    Gorsky, G.; Flood, P. R.; Youngbluth, M.; Picheral, M.; Grisoni, J.-M.

    2000-01-01

    A multi-instrumental array constructed in the Laboratoire d'Ecologie du Plancton Marin in Villefranche sur mer, France, named the Underwater Video Profiler (UVP), was used to investigate the vertical distribution of zooplankton in four western Norwegian fjords in the summer 1996. Six distinct zoological groups were monitored. The fauna included: (a) small crustaceans (mainly copepods), (b) ctenophores (mainly lobates), (c) siphonophores (mainly physonects), (d) a scyphomedusa Periphylla periphylla, (e) chaetognaths and (f) appendicularians. The use of the non-disturbing video technique demonstrated that the distribution of large zooplankton is heterogeneous vertically and geographically. Furthermore, the abundance of non-migrating filter feeders in the deep basins of the fjords indicates that there is enough food (living and non-living particulate organic matter) to support their dietary needs. This adaptation may be considered as a strategy for survival in fjords. Specifically, living in dark, deep water reduces visual predation and population loss encountered in the upper layer due to advective processes.

  8. 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

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration Agrium U.S., Inc., Kenai Nitrogen Operation, Including On-Site Leased Workers From NMS (Nana Management Systems) and Heat & Frost Insulation, Inc., Kenai, AK; Amended Notice of Revised Determination on Reconsideration...

  9. LIDAR Data on Plankton in a fjord in Washington State

    DTIC Science & Technology

    2011-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. LIDAR Data on Plankton in a fjord in Washington State Dr...2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE LIDAR Data on Plankton in a fjord in Washington State 5a

  10. A simple approach to adjust tidal forcing in fjord models

    NASA Astrophysics Data System (ADS)

    Hjelmervik, Karina; Kristensen, Nils Melsom; Staalstrøm, André; Røed, Lars Petter

    2017-07-01

    To model currents in a fjord accurate tidal forcing is of extreme importance. Due to complex topography with narrow and shallow straits, the tides in the innermost parts of a fjord are both shifted in phase and altered in amplitude compared to the tides in the open water outside the fjord. Commonly, coastal tide information extracted from global or regional models is used on the boundary of the fjord model. Since tides vary over short distances in shallower waters close to the coast, the global and regional tidal forcings are usually too coarse to achieve sufficiently accurate tides in fjords. We present a straightforward method to remedy this problem by simply adjusting the tides to fit the observed tides at the entrance of the fjord. To evaluate the method, we present results from the Oslofjord, Norway. A model for the fjord is first run using raw tidal forcing on its open boundary. By comparing modelled and observed time series of water level at a tidal gauge station close to the open boundary of the model, a factor for the amplitude and a shift in phase are computed. The amplitude factor and the phase shift are then applied to produce adjusted tidal forcing at the open boundary. Next, we rerun the fjord model using the adjusted tidal forcing. The results from the two runs are then compared to independent observations inside the fjord in terms of amplitude and phases of the various tidal components, the total tidal water level, and the depth integrated tidal currents. The results show improvements in the modelled tides in both the outer, and more importantly, the inner parts of the fjord.

  11. 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.

  12. Glacial conditioning of stream position and flooding in the braid plain of the Exit Glacier foreland, Alaska

    NASA Astrophysics Data System (ADS)

    Curran, Janet H.; Loso, Michael G.; Williams, Haley B.

    2017-09-01

    Flow spilling out of an active braid plain often signals the onset of channel migration or avulsion to previously occupied areas. In a recently deglaciated environment, distinguishing between shifts in active braid plain location, considered reversible by fluvial processes at short timescales, and more permanent glacier-conditioned changes in stream position can be critical to understanding flood hazards. Between 2009 and 2014, increased spilling from the Exit Creek braid plain in Kenai Fjords National Park, Alaska, repeatedly overtopped the only access road to the popular Exit Glacier visitor facilities and trails. To understand the likely cause of road flooding, we consider recent processes and the interplay between glacier and fluvial system dynamics since the maximum advance of the Little Ice Age, around 1815. Patterns of temperature and precipitation, the variables that drive high streamflow via snowmelt, glacier meltwater runoff, and rainfall, could not fully explain the timing of road floods. Comparison of high-resolution topographic data between 2008 and 2012 showed a strong pattern of braid plain aggradation along 3 km of glacier foreland, not unexpected at the base of mountainous glaciers and likely an impetus for channel migration. Historically, a dynamic zone follows the retreating glacier in which channel positions shift rapidly in response to changes in the glacier margin and fresh morainal deposits. This period of paraglacial adjustment lasts one to several decades at Exit Glacier. Subsequently, as moraine breaches consolidate and lock the channel into position, and as the stream regains the lower-elevation valley center, upper-elevation surfaces are abandoned as terraces inaccessible by fluvial processes for timescales of decades to centuries. Where not constrained by these terraces and moraines, the channel is free to migrate, which in this aggradational setting generates an alluvial fan at the breach of the final prominent moraine. The position of

  13. 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.

  14. Variation in mitochondrial DNA and allozymes discriminates early and late forms of Chinook salmon Oncorhynchus tshawytscha in the Kenai and Kasilof Rivers, AK

    USGS Publications Warehouse

    Adams, Noah S.; Spearman, William J.; Burger, Carl V.; Currens, Kenneth P.; Schreck, Carl B.; Li, Hiram W.

    1994-01-01

    Genetic differences between early and late forms of Alaskan chinook salmon (Oncorhynchus tshawytscha) were identified using two genetic approaches: mitochondrial DNA (mtDNA) analysis, and protein electrophoresis. Study populations consisted of early and late runs in each of the Kenai and Kasilof rivers in Alaska, and a population from the Minam River, Oregon. Two segments of mtDNA were amplified using the polymerase chain reaction (PCR) and digested with 14–16 restriction enzymes. Results showed that early runs were genetically similar to each other but different from the late runs. The late runs were different from each other based on the frequency of the common haplotypes. Frequency differences in shared haplotypes together with the presence of a unique haplotype separated the Minam River stock from those in Alaska. In the protein analysis, each population was examined at 30 allozyme loci. Based on 14 polymorphic loci, Minam River salmon were genetically distinct from the Alaskan populations. Within the Alaskan populations, early runs were most similar to each other but different from the late runs; the late runs were also genetically most similar to each other. Both mtDNA and allozyme analysis suggest that chinook salmon may segregate into genetically different early and late forms within a drainage.

  15. Geologic studies in Alaska by the U.S. Geological Survey, 1996

    USGS Publications Warehouse

    Gray, John E.; Riehle, James R.

    1998-01-01

    This collection of 12 papers continues the annual series of U.S. Geological Survey (USGS) reports on geologic investigations in Alaska. The annual volume presents results from new or ongoing studies in Alaska that are of interest to scientists in academia, industry, land and resource managers, and the general public. The Geological Studies in Alaska volume reports the results of studies that cover a broad spectrum of earth science topics from many parts of the state (fig. 1).The papers in this volume are organized under the topics Environment and Climate, Resources, and Geologic Framework, in order to reflect the objectives and scope of USGS programs that are currently active in Alaska. Environmental studies are the focus of two articles in this volume: One study addresses the relation between glaciers and aquatic habitat on the Kenai River and another study evaluates the geochemistry of water draining chromite deposits in Alaska. Two papers address mineral resources in southwestern Alaska including a geochemical study of the Fortyseven Creek prospect and a geological and geochemical study of the Stuyahok area. Eight geologic framework studies apply a variety of techniques to a wide range of subjects throughout Alaska, including biostratigraphy, geochemistry, geochronology, paleomagnetism, sedimentology, and tectonics.Two bibliographies at the end of the volume list reports about Alaska in USGS publications released in 1996 and reports about Alaska by USGS authors in non-USGS publications in 1996.

  16. 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.

  17. 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).

  18. Mesoscale eddies in the Gulf of Alaska: Observations and implications

    NASA Astrophysics Data System (ADS)

    Rovegno, Peter

    Mesoscale eddies in the Gulf of Alaska are thought to contribute to the shelf-slope exchange of nutrients and plankton, enhancing biological production. We report on a study of two anticyclonic mesoscale eddies in this region observed through in situ sampling during August and September 2007. Both eddies exhibited in their cores theta-S profiles with warmer, fresher water relative to the properties of the ambient basin water between 150 and 300 m depth. Hydrographic properties and satellite altimetry data were analyzed to identify likely formation regions for each feature. One eddy, sampled near Yakutat, Alaska, originated in the Sitka formation region (221-223° E); the second eddy, sampled south of Kodiak Island, originated near the Kenai Peninsula, southeast of the Kennedy and Stevenson entrances to Cook Inlet—an area not previously studied as a formation region. Subsequent analysis of 16 years of satellite altimeter data (from 1992 to 2008) with an algorithm designed to identify and track eddies revealed approximately 6 Kenai eddies that have formed in this region. Although this number constitutes only 3.2% of the 188 eddies identified by the algorithm during this period, it represents 15.4% of the 39 eddies that formed in or propagated westward into the Alaskan Stream.

  19. 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.

  20. Managing forest disturbances and community responses: lessons from the Kenai Peninsula, Alaska.

    Treesearch

    Courtney G. Flint; Richard. Haynes

    2006-01-01

    Managing forest disturbances can be complicated by diverse human community responses. Interview and quantitative analysis of mail surveys were used to assess risk perceptions and community actions in response to forest disturbance by spruce bark beetles. Despite high risk perception of immediate threats to personal safety and property, risk perceptions of broader...

  1. 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.

  2. First report of Armillaria sinapina, a cause of armillaria root disease, associated with a variety of forest tree hosts on sites with diverse climates in Alaska

    Treesearch

    N. B. Klopfenstein; J. E. Lundquist; J. W. Hanna; M.-S. Kim; G. I. McDonald

    2009-01-01

    In August of 2007, a preliminary survey was conducted in Alaska to evaluate potential impacts of climate change on forest trees. Armillaria sinapina, a root-disease pathogen, was isolated from conifer and hardwood hosts on climatically diverse sites spanning 675 km from the Kenai Peninsula to the Arctic Circle. Seven isolates (NKAK1, NKAK2, NKAK5, NKAK6, NKAK9F, NKAK13...

  3. 78 FR 65208 - Modification of Class D and E Airspace; Kenai, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ... surface area. This action includes the NOTAM information. Class D and Class E airspace designations are... effective September 15, 2013, which is incorporated by reference in 14 CFR 71.1. The Class D and Class E... Federal Aviation Administration 14 CFR Part 71 Modification of Class D and E Airspace; Kenai, AK...

  4. 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,...

  5. 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,...

  6. Monitoring and modeling terrestrial arthropod diversity on the Kenai National Wildlife Refuge

    Treesearch

    Matthew L. Bowser; John M. Morton

    2009-01-01

    The primary purpose of the Kenai National Wildlife Refuge (KENWR) is to "conserve fish and wildlife populations in their natural diversity," where "fish and wildlife" explicitly includes arthropods. To this end, we developed a Long Term Ecological Monitoring Program (LTEMP), a collaborative effort with the USDA Forest Inventory and Analysis (FIA)...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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 §...

  13. 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...

  14. 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...

  15. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false EGDA closures and restrictions. 13.1328 Section 13.1328 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  16. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false EGDA closures and restrictions. 13.1328 Section 13.1328 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  17. 36 CFR 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Harding Icefield Trail. 13.1308 Section 13.1308 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 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Harding Icefield Trail. 13.1308 Section 13.1308 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  19. 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...

  20. 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...

  1. 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 §...

  2. 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 §...

  3. 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 §...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false EGDA closures and restrictions. 13.1328 Section 13.1328 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  11. 36 CFR 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Harding Icefield Trail. 13.1308 Section 13.1308 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 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false EGDA closures and restrictions. 13.1328 Section 13.1328 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National Park...

  13. 36 CFR 13.1328 - EGDA closures and restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false EGDA closures and restrictions. 13.1328 Section 13.1328 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 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Harding Icefield Trail. 13.1308 Section 13.1308 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. 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.

  16. 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

  17. Marine-terminating glaciers sustain high productivity in Greenland fjords.

    PubMed

    Meire, Lorenz; Mortensen, John; Meire, Patrick; Juul-Pedersen, Thomas; Sejr, Mikael K; Rysgaard, Søren; Nygaard, Rasmus; Huybrechts, Philippe; Meysman, Filip J R

    2017-08-04

    Accelerated mass loss from the Greenland ice sheet leads to glacier retreat and an increasing input of glacial meltwater to the fjords and coastal waters around Greenland. These high latitude ecosystems are highly productive and sustain important fisheries, yet it remains uncertain how they will respond to future changes in the Arctic cryosphere. Here we show that marine-terminating glaciers play a crucial role in sustaining high productivity of the fjord ecosystems. Hydrographic and biogeochemical data from two fjord systems adjacent to the Greenland ice sheet, suggest that marine ecosystem productivity is very differently regulated in fjords influenced by either land-terminating or marine-terminating glaciers. Rising subsurface meltwater plumes originating from marine-terminating glaciers entrain large volumes of ambient deep water to the surface. The resulting upwelling of nutrient-rich deep water sustains a high phytoplankton productivity throughout summer in the fjord with marine-terminating glaciers. In contrast, the fjord with only land-terminating glaciers lack this upwelling mechanism, and is characterized by lower productivity. Data on commercial halibut landings support that coastal regions influenced by large marine-terminating glaciers have substantially higher marine productivity. These results suggest that a switch from marine-terminating to land-terminating glaciers can substantially alter the productivity in the coastal zone around Greenland with potentially large ecological and socio-economic implications. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

  18. New geochronological evidence for the timing of early Tertiary ridge subduction in southern Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

    USGS Publications Warehouse

    Bradley, Dwight C.; Parrish, Randall; Clendenen, William; Lux, Daniel R.; Layer, Paul W.; Heizler, Matthew; Donley, D. Thomas

    2000-01-01

    We present new U/Pb (monazite, zircon) and 40Ar/39Ar (biotite, amphibole) ages for 10 Tertiary plutons and dikes that intrude the Chugach–Prince William accretionary complex of southern Alaska. The Sanak pluton of Sanak Island yielded ages of 61.1±0.5 Ma (zircon) and 62.7±0.35 (biotite). The Shumagin pluton of Big Koniuji Island yielded a U/Pb zircon age of 61.1±0.3 Ma. Two biotite ages from the Kodiak batholith of Kodiak Island are nearly identical at 58.3±0.2 and 57.3±2.5 Ma. Amphibole from a dike at Malina Bay, Afognak Island, is 59.3±2.2 Ma; amphibole from a dike in Seldovia Bay, Kenai Peninsula, is 57.0±0.2 Ma. The Nuka pluton, Kenai Peninsula, yielded ages of 56.0±0.5 Ma (monazite) and 54.2±0.1 (biotite). Biotite plateau ages are reported for the Aialik (52.2±0.9 Ma), Tustumena (53.2±1.1 Ma), Chernof (54.2±1.1 Ma), and Hive Island (53.4±0.4 Ma) plutons of the Kenai Peninsula. Together, these new results confirm, but refine, the previously documented along-strike diachronous age trend of near-trench magmatism during the early Tertiary. We suggest that this event began at 61 Ma at Sanak Island, 2-4 m.y. later than previously supposed. An intermediate dike near Tutka Bay, Kenai Peninsula, yielded a hornblende age of 115±2 Ma. This represents a near-trench magmatic event that had heretofore gone unrecognized on the Kenai Peninsula; correlative Early Cretaceous near-trench plutons are known from the western Chugach Mountains near Palmer.

  19. 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.

  20. 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.

  1. 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.

  2. Hydrographic response of Hornsund Fjord (South Spitsbergen) to climate change

    NASA Astrophysics Data System (ADS)

    Promińska, Agnieszka; Falck, Eva; Walczowski, Waldemar

    2017-04-01

    Hornsund is the southernmost end-member in the network of fjords of western Spitsbergen. It is a medium, through which different waters mix, transform and affect land and marine ecosystems. It is a great laboratory for study of direct interaction between oceanic and land fjord boundaries as a response to climate change. Investigations in the fjord are mainly based on summer set of data collected every July between 2001 and 2016 during Arctic cruises on RV Oceania, a ship belonging to the Institute of Oceanology Polish Academy of Sciences. High resolution measurements of temperature and salinity were conducted using CTD probe in a scanfish mode. Supplementary data come from Polish-Norwegian cooperation in the AWAKE-2 project, which include hydrographic measurements carried out from a small boat in spring and late summer as well as a full year hydrographic record from moorings. Over 16-years of regular measurements significant changes in water temperature, salinity and water mass distribution in the fjord have been observed. Hydrographic patterns were strongly dependent on the extreme oceanic events in the Svalbard area, either massive flooding of the West Spitsbergen Shelf by the Atlantic Water or inflow of cold water and sea ice carried by the Sørkapp Current from the Barents Sea. Moreover, extremely warm winters observed during recent years and decrease in winter ice cover in the fjord had great implication on the Winter Cooled Water, which was typically seen in summer in the most inner part of the fjord, but seems to be a rare feature in the coming years. The first attempt to assess the role of the Sørkapp Current for Hornsund Fjord is addressed as well.

  3. Southeast Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of southeastern Alaska was acquired from data collected by MODIS on November 24, 2001. In it you can see the eastern most portion of the Aluetian Mountains (far left), as they give way to the crescent-shaped Alaska Range. The Alaska Range begins at the image's left and runs just to the right of the image's center, stopping short of crossing over into Canada's Yukon Territory. The most famous peak associated with the Alaska Range is of course Denali, which is casting an enormous shadow (upper left) as the setting sun moves ever closer to the horizon.

  4. Tsunamis generated by 3D granular landslides in various scenarios from fjords to conical islands

    NASA Astrophysics Data System (ADS)

    McFall, Brian C.; Fritz, Hermann M.

    2015-04-01

    Landslide generated tsunamis such as in Lituya Bay, Alaska 1958 account for some of the highest recorded tsunami runup heights. Source and runup scenarios based on real world events are physically modeled using generalized Froude similarity in the three dimensional NEES tsunami wave basin at Oregon State University. A novel pneumatic landslide tsunami generator (LTG) was deployed to simulate landslides with varying geometry and kinematics. The bathymetric and topographic scenarios tested with the LTG are the basin-wide propagation and runup, fjord, curved headland fjord and a conical island setting representing a landslide off an island or a volcano flank collapse. The LTG consists of a sliding box filled with 1,350 kg of landslide material which is accelerated by pneumatic pistons down slope. Two different landslide materials are used to study the granulometry effects: naturally rounded river gravel and cobble mixtures. Water surface elevations are recorded by an array of resistance wave gauges. The landslide deformation is measured from above and underwater camera recordings. The landslide deposit is measured on the basin floor with a multiple transducer acoustic array (MTA). Landslide surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. Wave runup is recorded with resistance wave gauges along the slope and verified with video image processing. The measured landslide and wave parameters are compared between the planar hill slope used in various scenarios and the convex hill slope of the conical island. The energy conversion rates from the landslide motion to the wave train is quantified for the planar and convex hill slopes. The wave runup data on the opposing headland is analyzed and evaluated with wave theories. The measured landslide and tsunami data serve to validate and advance three-dimensional numerical landslide tsunami prediction models.

  5. The Tsunami Generated by the October 17th, 2015 Taan Fjord landslide

    NASA Astrophysics Data System (ADS)

    Lynett, P. J.; Weiss, R.; Mattox, A.; Skanavis, V.; Ayca, A.; Tang, H.; Higman, B. M.; Stark, C. P.; Keen, A.

    2016-12-01

    On October 17th, 2015, the largest landslide in North America in decades occurred in Taan Fjord, an arm of southeast Alaska's Icy Bay. The landslide triggered an enormous local tsunami. Flow indicators from satellite imagery suggest that the maximum tsunami runup immediately adjacent to the slide mass exceeds 190 m. Such a maximum runup would be second only to that created by the 1958 Lituya Bay landslide, a poorly recorded (by modern standards) event that is nonetheless the most important dataset for understanding extreme landslide tsunami hazards available to the engineering community. From numerical simulations and reconnaissance trips, we see widespread areas where the tsunami runup exceeds 100 meters in elevation. Furthermore, at least 90% of the 50 km of shoreline in the Fjord appears to have experienced runup elevations greater than 20 m.. With these large elevations comes large inundation distances. Often, the runup limit penetrated 10's to 100's of meters into dense brush and forest. Furthermore, along the edges of the trimlines, there was often a 3m+ high pile of debris consisting mostly of trees (see Figure). All of these factors make the tools of a common tsunami field survey - a laser rangefinder and a survey rod - effectively useless. Owing to this extreme runup and inundation distances, as well as the remote location, the team used a high-accuracy Real Time Kinematic (RTK) survey system, which provides 10-cm accuracy location elevations, after the data is tide-corrected. The types of data to be presented include the most-important runup elevations, flow depth profiles, areas of sediment scour and deposition, debris piles, and the impact of the tsunami on various types of vegetation.

  6. 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…

  7. 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.

  8. 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.

  9. 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.

  10. Polycyclic aromatic hydrocarbons in sediments from the Saguenay Fjord, Canada

    SciTech Connect

    Martel, L.; Gagnon, M.J.; Masse, R.; Leclerc, A.; Tremblay, L.

    1986-07-01

    The purpose of this study is to determine the spatial distribution of PAH concentrations in the Saguenay Fjord surface sediments and to study the behavior of these compounds in this marine environment. This 100 km river is the major tributary to the St-Lawrence estuary. It is highly industrialized and aluminium smelting plants, which dominate the industrial sector, are apparently the major source of PAH to the river. Moreover, a study has shown high levels of PAH in the sediments of Baie des Haexclamation Haexclamation in the Saguenay Fjord.

  11. 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, Spencer J.; Shirley, Thomas C.; Mondragon, Jennifer

    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.

  12. 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

  13. 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.

  14. Baroclinic annular variability of internal motions in a Patagonian fjord

    NASA Astrophysics Data System (ADS)

    Ross, Lauren; Valle-Levinson, Arnoldo; Pérez-Santos, Iván.; Tapia, Fabian J.; Schneider, Wolfgang

    2015-08-01

    Time series of horizontal velocities, echo intensity, wind velocity, and atmospheric pressure were collected for ˜200 days in a Patagonian fjord to explore pycnocline motions produced by the Southern Hemisphere's baroclinic annular mode (BAM). The BAM variability occurs between 20 and 30 days and is associated with fluctuations in atmospheric kinetic energy and in turbulent fluxes of heat. Spectra of horizontal velocities and normalized echo intensity in the fjord's water showed highest energy between 25 and 30 days. This was explained by sustained westerly winds associated with extreme low-pressure systems (˜900 hPa) that had periodicity related to the BAM. Wind forcing produced >40 cm s-1 along-channel and cross-channel currents in the surface layer, which in turn created a wind-induced setup toward the head of the fjord. The setup was accompanied by a deepening of the pycnocline (from 5 to 15 m depth) with ˜25 to 30 day periodicity, as derived from the normalized echo intensity. The dominant empirical orthogonal function mode of the normalized echo intensity profiles explained 70.8% of the variance and also exhibited a ˜25-30 day periodicity. Further, a wavelet and spectral analysis of 10 years of atmospheric pressure indicated peaks between 25 and 30 days each year, indicating that the BAM consistently influences weather patterns in Chilean Patagonia. This is the first documented case of baroclinic annular variability in a specific region of the Southern Hemisphere, and of its effects on fjord systems.

  15. Biomarkers in fish from dioxin-contaminated fjords.

    PubMed

    Hylland, K; O Aspholm, O; Knutsen, J A; Ruus, A

    2006-01-01

    The Grenland fjords, southern Norway, have been heavily contaminated by dibenzo-p-dioxins and dibenzofurans (dioxins) over decades through inputs from a magnesium smelter. Despite radically decreased inputs since 1990, there are still high levels of dioxins in both biotic and abiotic components of the fjords. The aim of the study was to establish whether biomarkers' responses in three fish species, Atlantic cod (Gadus morhua L.), sea-trout (anadromous brown trout, Salmo trutta L.) and flounder (Platichthys flesus L.), could be used to discern the effects in the most contaminated ecosystem, Frierfjord, from the effects in the adjacent, less-contaminated ecosystem, Eidangerfjord. Biomarker responses clearly indicated that the three fish species were affected by dioxin exposure. Phase I responses in cod and trout could be used to differentiate exposure in the two fjord ecosystems. Phase II responses (glutathione S-transferase) in cod and trout similarly indicated a higher dioxin exposure in Frierfjord compared with Eidangerfjord. Results for glutathione S-transferase and glutathione reductase indicated different exposure levels in the two fjords, but also showed seasonal variability, and the results highlighted the need for baseline data for these biomarkers.

  16. 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.

  17. Analysis of recent vessel arrivals and ballast water discharge in Alaska: toward assessing ship-mediated invasion risk.

    PubMed

    McGee, Steven; Piorkowski, Robert; Ruiz, Gregory

    2006-12-01

    Ships are a dominant vector for biological invasions through ballast water discharge (BWD) and hull fouling. Here, we provide a first comprehensive analysis of shipping in Alaska, summarizing (a) the number, type and origin of vessel arrivals to Alaska for 2003 and 2004, (b) the spatial and temporal variation in vessel traffic, and (c) the available data on ballast water discharge in order to prioritize locations for tracking biological invasions. Most arrivals were passenger vessels, followed by ferries and fishing vessels, all of which carried little ballast water. Regional and seasonal patterns in arrivals and BWD were unevenly distributed among vessel types. The majority of vessels reporting BWD were from foreign ports, and most of this ballast was untreated. The largest volumes of ballast were from tankers at Valdez and Kenai Peninsula ports. Although Alaska has few documented invasions, opportunities for ship-mediated transfer now appear high and warrant further scrutiny.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. Status of sea otter populations in southcentral and southeast Alaska, 2002-2003

    USGS Publications Warehouse

    Bodkin, James L.; Maldini, Daniela; Calkins, Donald; Atkinson, Shannon; Meehan, Rosa

    2004-01-01

    During the years 2002-2004 estimated sea otter population sizes were calculated for Southeast Alaska, Prince William Sound, and the Kenai Peninsula and Cook Inlet regions of Alaska. Aerial surveys were conducted by a single observer from a float-equipped Bellanca Scout fixed-wing aircraft flying at 91 m altitude and 65 mph. The surveys followed protocols written by Bodkin and Udevitz (1999). The survey design consisted of systematic sampling of 400 m wide transects that were uniformly placed throughout the survey area. Selection and sampling of transects was proportional to expected sea otter abundance, with most effort taking place in transects over waters 0-40 m in depth. Intensive searches were periodically conducted within transects to estimate the proportion of sea otters not detected on strips. To obtain an adjusted population size estimate, strip counts are adjusted for the area not surveyed and by a correction factor.

  3. Bathymetry and seismic stratigraphy of East Greenland fjords and sounds

    NASA Astrophysics Data System (ADS)

    Forwick, Matthias; Sverre Laberg, Jan; Husum, Katrine; Olsen, Ingrid L.

    2014-05-01

    Swath bathymetry and high-resolution penetration echo sounder (chirp) data from fjords and sounds between Kong Oscars Fjord (~72°30') and Bredefjord (~75°30'), East Greenland, reveal a variety of sedimentary processes related to glacial activity and mass wasting, as well as evidence of tectonic activity. The large-scale bathymetry of most fjords and sounds is characterized by sills that occasionally are shallower than 30 m, and basins reaching maximum water depths of more than 760 m. Multiple "steps", some more than 250 meters high and with gradients exceeding 60° (e.g. in Bredefjord) are most probably related to vertical movements along tectonic lineaments. The basin floors are typically smooth suggesting sedimentation predominantly from suspension settling. However, an approx. 100 m wide and 5 m deep channel in Kempefjord provides evidence of gravity-flow erosion sub-parallel to the fjord axis. Multiple sediment lobes along the fjord sides reflect repeated mass wasting. Relatively straight linear features oriented parallel to the fjord axes are interpreted to be glacial lineations that were formed beneath fast-flowing ice draining the Greenland Ice Sheet. They occur rarely on shallower plateaus and are often overlain by transverse ridges. In Youngsund, such ridges are typically 1-2 m high, 50 m wide and the distances between crests are most often approx. 100 m. The ridges are most probably 'retreat moraines' that were deposited during minor halts and/or re-advances during the last deglaciation. More curvilinear and randomly oriented furrows with raised rims are most probably iceberg ploughmarks that were formed from grounded icebergs calving off the Greenland Ice Sheet during the last deglaciation (e.g. in Rudis Bugt). Elongated to round, randomly distributed depressions of up to >10 m depth and >200 m width occur, e.g. in the inner parts of Tyrolerfjord. They are often filled with acoustically stratified sediments and we assume that they might have resulted

  4. 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.

  5. Modeling Interseismic and Transient Deformation in Southcentral Alaska

    NASA Astrophysics Data System (ADS)

    Freed, A. M.; Ali, T.

    2009-12-01

    The convergent margin of Southern Alaska marks the active tectonic boundary between the North American and Pacific plates. Here we numerically model the response of the Alaskan lithosphere to interseismic, coseismic and postseismic loading in order to interpret the contemporary velocity field from GPS observations. Results suggest that, to first order, the surface velocities can be explained by the combination of interseismic deformation associated with a locked megathrust and postseismic viscous relaxation following large earthquakes, particularly the 1964 M9.2 Great Alaska earthquake. The best fitting model requires a weak mantle wedge sandwiched between a strong crust and the subducting slab. Most of the trenchward directed velocities observed in the GPS data, near the Kenai Peninsula and Kodiak Island as well in interior Alaska north of the Denali Fault, are a viscous relaxation response to the 1964 earthquake. In a few decades we should begin to see these velocities decay and subsequently point northwestwards. Postseismic viscous relaxation associated with large strike slip earthquakes since 1949 on the Queen Charlotte-Fairweather faults only provide a small contribution (~5mm/yr) to the present day GPS velocity field in that region. Our models demonstrate how subduction of the Pacific plate tends to load all the major faults at the margin including the central and eastern segments of the Denali fault and show how the 1964 earthquake and associated postseismic relaxation combined to increase Coulomb stress at the fault segment that ruptured during the 2002 M7.9 Denali earthquake.

  6. Sedimentary Carbon Stocks: A National Assessment of Scotland's Fjords.

    NASA Astrophysics Data System (ADS)

    Smeaton, Craig; Austin, William; Davies, Althea; Howe, John

    2017-04-01

    Coastal sediments have been shown to be globally significant repositories for carbon (C) with an estimated 126.2 Tg of C being buried annually (Duarte et al. 2005). Though it is clear these areas are important for the long-term storage of C the actual quantity of C held within coastal sediment remains largely unaccounted for. The first step to understanding the role the coastal ocean plays in the global C cycle is to quantify the C held within these coastal sediments. Of the different coastal environment fjords have been shown to be hotspots for C burial with approximately 11 % of the annual global marine carbon sequestration occurring within fjordic environments (Smith et al. 2015). Through the development of a joint geophysical and geochemical methodology we estimated that the sediment in a mid-latitude fjord holds 26.9 ± 0.5 Mt of C (Smeaton et al., 2016), with these results suggesting that Scottish mid-latitude fjords could be a significant unaccounted store of C equivalent to their terrestrial counterparts (i.e. peatlands). Through the application of the joint geophysical and geochemical methodology developed by Smeaton et al (2016) to a number of other mid-latitude fjords, we will create detailed estimations of the sedimentary C stored at these individual sites. Using these detailed C stock estimations in conjunction with upscaling techniques we will establish the first national estimation of fjordic sedimentary C stocks. The data produced will allow for the sedimentary C stocks to be compared to other national C stocks, such as the Scottish peatlands (Chapman et al. 2009) and forestry (Forestry Commission, 2016). Alongside quantifying this large unaccounted for store of C in the coastal ocean this work also lays foundations for future work to understand the role of the coastal ocean in the global C cycle. Duarte, C. M., Middelburg, J. J., and Caraco, N.: Major role of marine vegetation on the oceanic carbon cycle, Biogeosciences, 2, 1-8, doi:10.5194/bg-2

  7. 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.

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. Bathymetry in Petermann fjord from Operation IceBridge aerogravity

    NASA Astrophysics Data System (ADS)

    Tinto, Kirsty J.; Bell, Robin E.; Cochran, James R.; Münchow, Andreas

    2015-07-01

    Petermann Glacier is a major glacier in northern Greenland, maintaining one of the few remaining floating ice tongues in Greenland. Monitoring programs, such as NASA's Operation IceBridge have surveyed Petermann Glacier over several decades and have found it to be stable in terms of mass balance, velocity and grounding-line position. The future vulnerability of this large glacier to changing ocean temperatures and climate depends on the ocean-ice interactions beneath its floating tongue. These cannot currently be predicted due to a lack of knowledge of the bathymetry underneath the ice tongue. Here we use aerogravity data from Operation IceBridge, together with airborne radar and laser data and shipborne bathymetry-soundings to model the bathymetry beneath the Petermann ice tongue. We find a basement-cored inner sill at 540-610 m depth that results in a water cavity with minimum thickness of 400 m about 25 km from the grounding line. The sill is coincident with the location of the melt rate minimum. Seaward of the sill the fjord is strongly asymmetric. The deepest point occurs on the eastern side of the fjord at 1150 m, 600 m deeper than on the western side. This asymmetry is due to a sedimentary deposit on the western side of the fjord. A 350-410 m-deep outer sill, also mapped by marine surveys, marks the seaward end of the fjord. This outer sill is aligned with the proposed Last Glacial Maximum (LGM) grounding-line position for Petermann Glacier. The inner sill likely provided a stable pinning point for the grounding line in the past, punctuating the retreat of Petermann Glacier since the LGM.

  14. Distribution and relative abundance of sea otters in south-central and south-western Alaska before or at the time of the T/V Exxon Valdez oil spill

    USGS Publications Warehouse

    DeGange, Anthony R.; Monson, Daniel H.; Irons, David B.; Robbins, C.M.; Douglas, David C.; Bayha, Keith; Kormendy, Jennifer

    1990-01-01

    Surveys of sea otters (Enhydra lutris) conducted before, immediately after, or at the time of the TA^ Exxon Valdez oil spill were used to guide otter capture efforts and assess the immediate effects of the spill. Shoreline counts (by boat) of sea otters in Prince William Sound in 1984 suggested that a minimum of 4,500 sea otters inhabited nearshore waters of Prince William Sound. Areas of highest density within the western portion of Prince William Sound included the Bainbridge Island area, Montague Island, Green Island, and Port Wells. About 1,330 sea otters were counted from helicopters along the coast of the Kenai Peninsula. Highest densities of sea otters were found along the western end of the Kenai Peninsula. At Kodiak Island, about 3,500 sea otters were counted in coastal surveys from helicopters. Highest densities of sea otters were found in Perenosa Bay in northern Afognak Island, and in waters between Afogneik, Kodiak, and Raspberry Islands. Along the Alaska Peninsula, about 6,500 sea otters were counted between Kamishak Bay and Unimak Pass. Areas of concentration included the Izembek Lagoon airea. False Pass, the Pavlof Islands, Hallo Bay, and Kujulik Bay. Line transect surveys conducted offshore of the coastal strips indicate that at the time of the surveys relatively high densities of sea otters existed offshore at Kodiak Island and along the Alaska Peninsula, but not on the Kenai Peninsula.

  15. Multibeam bathymetry and CTD measurements in two fjord systems in southeastern Greenland

    NASA Astrophysics Data System (ADS)

    Kjellerup Kjeldsen, Kristian; Weinrebe, Reimer Wilhelm; Bendtsen, Jørgen; Anker Bjørk, Anders; Kjær, Kurt Henrik

    2017-08-01

    We present bathymetry and hydrological observations collected in the summer of 2014 from two fjord systems in southeastern Greenland with a multibeam sonar system. Our results provide a detailed bathymetric map of the fjord complex around the island of Skjoldungen in Skjoldungen Fjord and the outer part of Timmiarmiut Fjord and show far greater depths compared to the International Bathymetric Chart of the Arctic Ocean. The hydrography collected shows different properties in the fjords with the bottom water masses below 240 m in Timmiarmiut Fjord being 1-2 °C warmer than in the two fjords around Skjoldungen, but data also illustrate the influence of sills on the exchange of deeper water masses within fjords. Moreover, evidence of subglacial discharge in Timmiarmiut Fjord, which is consistent with satellite observations of ice mélange set into motion, adds to our increasing understanding of the distribution of subglacial meltwater. Data are available through the PANGAEA website at https://doi.pangaea.de/10.1594/PANGAEA.860627.

  16. 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

  17. 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.

  18. Late Holocene paleoseismology of Shuyak Island, Kodiak Archipelago, Alaska - surface deformation and plate segmentation within the 1964 Alaska M 9.2 earthquake rupture zone

    NASA Astrophysics Data System (ADS)

    Brader, Martin; Shennan, Ian; Barlow, Natasha; Davies, Frank; Longley, Chris; Tunstall, Neil

    2017-04-01

    Recent paleoseismological studies question whether segment boundaries identified for 20th and 21st century great, >M 8, earthquakes persist through multiple earthquake cycles, or whether smaller segments with different boundaries rupture and cause significant hazards. The smaller segments may include some that are currently slipping rather than locked. The 1964 Alaska M 9.2 earthquake was the largest of five earthquakes of >M 7.9 between 1938 and 1965 along the Aleutian chain and coast of southcentral Alaska that helped define models of rupture segments along the Alaska-Aleutian megathrust. The 1964 M 9.2 earthquake ruptured ˜950 km of the megathrust, involving two main asperities focussed on Kodiak Island and Prince William Sound and crossed the Kenai segment, which is currently creeping. Paleoseismic studies of coastal sediments currently provide a long record of previous large earthquakes for the Prince William Sound segment, with widespread evidence of seven great earthquakes in the last 4000 years and more restricted evidence for three earlier ones. Shorter and more fragmentary records from the Kenai Peninsula, Yakataga and Kodiak Archipelago raise the hypothesis of different patterns of surface deformation during past great earthquakes. We present new evidence from coastal wetlands on Shuyak Island, towards the hypothesised north-eastern boundary of the Kodiak segment, to illustrate different detection limits of paleoseismic indicators and how these influence the identification of segment boundaries in late Holocene earthquakes. We compare predictions of co-seismic uplift and subsidence derived from geophysical models of earthquakes with different rupture modes. The spatial patterns of agreement and misfit between model predictions and quantitative reconstructions of co-seismic submergence and emergence suggest that no earthquake within the last 4000 years had the same rupture pattern as the 1964 M 9.2 earthquake.

  19. Eastern Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this SeaWiFS image of eastern Alaska, the Aleutian Islands, Kodiak Island, Yukon and Tanana rivers are clearly visible. Also visible, but slightly hidden beneath the clouds, is a bloom in Bristol Bay. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  20. Glacimarine sedimentation in Petermann Fjord and Nares Strait, NW Greenland

    NASA Astrophysics Data System (ADS)

    Hogan, Kelly; Jakobsson, Martin; Mayer, Larry; Mix, Alan; Nielsen, Tove; Kamla, Elina; Reilly, Brendan; Heirman, Katrina An; Stranne, Christian; Mohammed, Rezwan; Eriksson, Bjorn; Jerram, Kevin

    2017-04-01

    Here we build on preliminary results from 6500 line-km of high-resolution chirp sub-bottom profiles (2-7 kHz) acquired in Petermann Fjord and Nares Strait during the Petermann 2015 Expedition of the Swedish icebreaker Oden. We map the unlithified sediment cover in Peterman Fjord, which consists of up to 3 conformable "drape" units and calculate volumes of this assumed "post-glacial" fill. In Nares Strait we have mapped sediment volumes in local basins just beyond the sill at the Petermann Fjord-mouth: do these sediments represent material flushed out from the grounding zone of Petermann Glacier when it was grounded at the sill? In this vein, and interestingly, some of the thickest sediments that we observe are found close to a grounding-zone wedge (GZW) in Nares Strait that represents a former grounding zone of ice retreating southwards through the strait. We also map conformable units across Nares Strait and consider the similarities between these and the sediment units in the fjord. Do the strong reflections between the units represent the same climatic, oceanographic or process-shift both inside and outside the fjord? We also aim to tie our new acoustic stratigraphy to sediment-core data (lithofacies, dates) and, therefore, to comment on the age of the mapped sediment units and present ideas on the glacimarine flux of material to the Petermann-Nares system. Primary sediment delivery to the seafloor in this environment is thought to be predominantly through sedimentation from meltwater plumes but also of iceberg-rafted debris (IRD). However, sediment redeposition by slope failures on a variety of scales also occurs and has focussed sediments into discrete basins where the seafloor is rugged. This work - which aims to relate past sediment, meltwater and iceberg fluxes to changes in climate - will help us to identify how the system has responded to a past global warming event, namely the last deglaciation. This is particularly relevant in light of the recent

  1. Bathymetry and geology of Greenlandic fjords from Operation IceBridge airborne gravimetry

    NASA Astrophysics Data System (ADS)

    Tinto, K. J.; Cochran, J. R.; Bell, R. E.; Charles, K.; Dube, J.; McLeish, M.; Burton, B. L.

    2011-12-01

    The Greenland Ice Sheet is drained by outlet glaciers that commonly flow into long, deep fjords. Glacier flow is controlled in part by the topography and geology of the glacier bed, and is also affected by the interaction between ice and sea water in the fjords. This interaction depends on the bathymetry of the fjords, and particularly on the presence of bathymetric sills, which can control the influx of warm, saline water towards the grounding zone. The bathymetry and geology of these fjords provide boundary conditions for models of the behaviour of the glaciers and ice sheet. Greenlandic fjords can be over 100 km long and up to 1000 m deep, with sills a few hundred metres above the bottom of the fjord. Where bathymetry is not well known, the scale of these features makes them appropriate targets for aerogravity surveys. Where bathymetry is known, aerogravity can provide information on the geology of the fjord, but the sometimes narrow, sinuous fjords present challenges for both data acquisition and interpretation. In 2010 and 2011 Operation IceBridge flew the Sander Geophysics AIRGrav system along the axes of more than 40 outlet glaciers distributed around the coast of Greenland. The AIRGrav system has high precision, fast recovery from turns and the capacity for draped flights, all of which improve the quality of data acquisition along fjord axes. Operation IceBridge survey flights are conducted at or lower than 500 m above ground surface, at speeds of ~140 m/s, allowing full amplitude resolution of features larger than ~5 km, and detection of smaller scale features. Fjord axis data are commonly of lower quality than data from grid-based gravity surveys. Interpretation of these data is improved by combining repeated survey lines from both seasons as well as incorporating other datasets, such as radar, and magnetic data from Operation IceBridge, digital elevation models and geological maps. While most fjords were surveyed by a single axial track, surveys of

  2. Organic Carbon Dynamics in Fjords: A Case Study of Fiordland, New Zealand

    NASA Astrophysics Data System (ADS)

    Cui, X.; Bianchi, T. S.; Savage, C.

    2016-02-01

    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. In this study, we use sediments from Fiordland, New Zealand to examine the relative importance of different terrestrially derived OC in fjord sediments and assess the role of hydrodynamic sorting in distributing sediments and OC along fjords. Sediments and terrestrial end-members were collected for organic geochemistry analysis to examine the efficiency of terrestrial OC burial, both in this system and in fjords globally. In addition, selective surface sediment samples were used for density fractionation separation, bulk OC and compound specific radiocarbon analysis (CSRA). End-member models indicated that 69% and 61% of OC in Fiordland and global fjord sediments were terrestrially derived, respectively. There was a decreasing trend of terrestrially derived OC down fjords, which was contributed by hydrodynamic sorting. Comparatively, less hydrodynamic sorting in fjords than large river estuary -coastal systems contributed to high burial rates of OC in fjords. However, our bulk OC radiocarbon and CSRA results suggested minimal contribution of petrogenic OC by bedrock erosion. Here we suggest that global fjords may play an important role in regulating atmospheric CO2 levels by burying purely modern OC, in contrast to other systems. Globally, fjords bury 11.3 ± 4.4 × 1012 g OCterr, which accounts for 18% of all the OCterr buried in all marine sediments annually. This new information has now increased the total global OCterr pool buried in marine sediments from 58 to 63 (× 1012 g), which better constrains the "missing sink" in OCterr burial in the global ocean. Our results indicate that watershed soil residence times, fjord water depth, and dissolved oxygen levels were more important than mass accumulation rates (MAR) in controlling OC burial.

  3. 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

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

    USGS Publications Warehouse

    Atterby, Clara; Ramey, Andrew M.; Gustafsson Hall, Gabriel; Jarhult, Josef; Borjesson, Stefan; Bonnedahl, Jonas

    2016-01-01

    BackgroundAntibiotic-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.MethodsEscherichia 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.ResultsScreening 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.ConclusionOur 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Erosion of modern terrestrial organic matter as a major component of sediments in fjords

    NASA Astrophysics Data System (ADS)

    Cui, Xingqian; Bianchi, Thomas S.; Savage, Candida

    2017-02-01

    Fjords have recently been recognized as "hot spots" of carbon burial. In this study, we investigated organic carbon (OC) and biomarker radiocarbon values in fjord sediments from New Zealand. Our results showed that OC was mostly modern with the most aged OC in middle reaches of fjords, likely related to hydrodynamic sorting and inputs along adjacent slopes. Radiocarbon ages of sedimentary OC increased from north-to-south, consistent with the Fiordland regional gradients of lower fjord slopes and less rainfall. Our biomarker results suggested that lignin and long-chain fatty acids were preferentially linked with fresh terrestrial debris and degraded soil, respectively, likely due to their chemical and physical properties. Finally, we propose that fjords are a significant sink of modern OC, in contrast to large lowland coastal systems as a major sink of preaged OC. Overall, this study indicated that radiocarbon techniques are critical in investigating carbon dynamics in coastal systems.

  10. 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

  11. 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.

  12. 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

  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. 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

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

    PubMed

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

    2015-02-17

    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.

  16. 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.

  17. 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.

  18. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE MINERALS Miscellaneous Minerals Provisions § 228.80... approving a plan of operations, the authorized officer must consider: (1) The resources of...

  19. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE MINERALS Miscellaneous Minerals Provisions § 228.80... approving a plan of operations, the authorized officer must consider: (1) The resources of...

  20. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE MINERALS Miscellaneous Minerals Provisions § 228.80... approving a plan of operations, the authorized officer must consider: (1) The resources of...

  1. 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.

  2. 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.

  3. 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..

  4. Road proximity increases risk of skeletal abnormalities in wood frogs from National Wildlife Refuges in Alaska.

    PubMed

    Reeves, Mari K; Dolph, Christine L; Zimmer, Heidi; Tjeerdema, Ronald S; Trust, Kimberly A

    2008-08-01

    Skeletal and eye abnormalities in amphibians are not well understood, and they appear to be increasing while global populations decline. Here, we present the first study of amphibian abnormalities in Alaska. In this study we investigated the relationship between anthropogenic influences and the probability of skeletal and eye abnormalities in Alaskan wood frogs (Rana sylvatica). From 2000 to 2006, we examined 9,269 metamorphic wood frogs from 86 breeding sites on five National Wildlife Refuges: Arctic, Innoko, Kenai, Tetlin, and Yukon Delta. Using road proximity as a proxy for human development, we tested relationships between skeletal and eye abnormalities and anthropogenic effects. We also examined a subsample of 458 frogs for the trematode parasite Ribeiroia ondatrae, a known cause of amphibian limb abnormalities. Prevalence of skeletal and eye abnormalities at Alaskan refuges ranged from 1.5% to 7.9% and were as high as 20% at individual breeding sites. Proximity to roads increased the risk of skeletal abnormalities (p = 0.004) but not eye abnormalities. The only significant predictor of eye abnormalities was year sampled (p = 0.006). R. ondatrae was not detected in any Alaskan wood frogs. Abnormality prevalence at road-accessible sites in the Kenai and Tetlin refuges is among the highest reported in the published literature. Proximity to roads is positively correlated with risk of skeletal abnormalities in Alaskan wood frogs.

  5. Road Proximity Increases Risk of Skeletal Abnormalities in Wood Frogs from National Wildlife Refuges in Alaska

    PubMed Central

    Reeves, Mari K.; Dolph, Christine L.; Zimmer, Heidi; Tjeerdema, Ronald S.; Trust, Kimberly A.

    2008-01-01

    Background Skeletal and eye abnormalities in amphibians are not well understood, and they appear to be increasing while global populations decline. Here, we present the first study of amphibian abnormalities in Alaska. Objective In this study we investigated the relationship between anthropogenic influences and the probability of skeletal and eye abnormalities in Alaskan wood frogs (Rana sylvatica). Methods From 2000 to 2006, we examined 9,269 metamorphic wood frogs from 86 breeding sites on five National Wildlife Refuges: Arctic, Innoko, Kenai, Tetlin, and Yukon Delta. Using road proximity as a proxy for human development, we tested relationships between skeletal and eye abnormalities and anthropogenic effects. We also examined a subsample of 458 frogs for the trematode parasite Ribeiroia ondatrae, a known cause of amphibian limb abnormalities. Results Prevalence of skeletal and eye abnormalities at Alaskan refuges ranged from 1.5% to 7.9% and were as high as 20% at individual breeding sites. Proximity to roads increased the risk of skeletal abnormalities (p = 0.004) but not eye abnormalities. The only significant predictor of eye abnormalities was year sampled (p = 0.006). R. ondatrae was not detected in any Alaskan wood frogs. Conclusions Abnormality prevalence at road-accessible sites in the Kenai and Tetlin refuges is among the highest reported in the published literature. Proximity to roads is positively correlated with risk of skeletal abnormalities in Alaskan wood frogs. PMID:18709167

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. Adjacent fjords and glaciers respond differently to ice sheet surface melt in West Greenland

    NASA Astrophysics Data System (ADS)

    Bartholomaus, T. C.; Stearns, L. A.; Sutherland, D.; Shroyer, E.; Nash, J. D.; Walker, R. T.; Catania, G. A.; Felikson, D.; Carroll, D.; Fried, M.; Noel, B.; van den Broeke, M. R.

    2016-12-01

    Neighboring tidewater glaciers often exhibit asynchronous dynamic behavior, despite relatively uniform regional atmospheric and oceanic forcings. This variability may be controlled by a combination of local factors, including glacier and fjord geometry, fjord heat content and circulation, and glacier surface melt. In order to characterize and understand contrasts in adjacent tidewater glacier and fjord dynamics, we made coincident ice-ocean-atmosphere observations at high temporal resolution (minutes to weeks) within a 10,000 km^2 area near Uummannaq, Greenland. Water column velocity, temperature and salinity measurements reveal systematic differences in neighboring fjords that imply contrasting circulation patterns. The observed ocean velocity and hydrography, combined with numerical modeling, suggest that subglacial discharge plays a major role in setting fjord conditions. In addition, satellite remote sensing of seasonal ice flow speed and terminus position reveal both speedup and slow-down in response to melt, as well as differences in calving style among the neighboring glaciers. Glacier force budgets and modeling also point toward subglacial discharge as a key factor in glacier behavior. For the studied region, individual glacier and fjord geometry modulate subglacial discharge, which leads to contrasts in both fjord and glacier dynamics.

  12. Methane in a Swedish sill fjord - Benthic fluxes, inventory and atmospheric emission

    NASA Astrophysics Data System (ADS)

    Rütting, Tobias; Stigebrandt, Anders; de Brabandere, Loreto; Klemedtsson, Leif; Hall, Per

    2010-05-01

    Methane (CH4) is a potent greenhouse gas, which has the second largest radiative force after carbon dioxide. Oceans, including their coastal areas, contribute to the natural CH4 budget in the atmosphere, but measurements are still sparse, and no measurements of CH4 in Swedish fjord systems have been made. For this purpose we measured CH4 concentrations in the water column as well as benthic CH4 fluxes by using in-situ chambers on four occasions during 2009. The study area, the By Fjord, is a sill fjord on the Swedish west coast. Benthic flux measurements were done on a depth transect in the fjord and included both sediments with overlying oxic and anoxic water. The collected data were used to calculate the total fjord integrated net CH4 release from sediments, the transport through the water column, and finally the exchange between water and atmosphere. Moreover, we used modeling to estimate the total CH4 emission to the atmosphere from the By Fjord, which could be used as proxy for similar Scandinavian fjord systems. We will furthermore discuss our findings on CH4 in relation to simultaneous measurements of oxygen, NO3-, Fe, Mn and H2S, and the extent of CH4 oxidation in the water column. The presented results are of special importance even on a European scale, as they fill a gap in CH4 investigations according to a recent review of CH4 in European coastal waters.

  13. 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.

  14. 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

  15. Holocene sediment accumulation rates in fjords and bays of Chilean Patagonia and the Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Wellner, J. S.; Anderson, J. B.; Milliken, K.; Fernandez, R.; Michalchuk, B.; Boyd, B.

    2007-12-01

    Beginning in 2005 and ending in May of 2007, we completed a series of four research cruises in the fjords and bays of Chilean Patagonia and the Antarctic Peninsula aimed, in part, at determining the style and rate of Holocene sediment accumulation in a range of glacial settings. Our original hypothesis stated that rates of glacial erosion are a function of sliding speed, and are therefore expected to diminish sharply as basal temperatures drop below the melting point. To test this hypothesis, we measured sediment accumulation in tidewater glacier fjords ranging from fast-moving temperate glaciers in Patagonia to slower moving polar glaciers on the Antarctic Peninsula. Four fjords were surveyed in Patagonia ranging from San Rafael fjord in the Northern Patagonia ice field to Marinelli fjord in Tierra del Fuego. The cruises to the Antarctic Peninsula included two SHALDRIL legs during which drill cores recovered 108 m and 80 m of Holocene sediment in Maxwell Bay, South Shetland Islands, and the Firth of Tay in the northwestern Weddell Sea, respectively. An additional nine fjords across the northern peninsula were surveyed with kasten and jumbo piston cores. To date, we have completed nearly 100 radiocarbon dates from fossil carbonate material, both shells and foraminifera, extracted from the sediment cores obtained in these fjords. Our initial results highlight the complexity of the controls on sediment yields and the extreme variability in sediment accumulation amongst fjords. While climate may be the first order control on glacier erosion rates and sediment transport to bays and fjords, several other factors must significantly influence these processes and may mask the broader signal. Our ongoing work with this newly acquired comprehensive dataset is examining additional controls including drainage basin size, precipitation gradient, altitude of the glaciers, and glacial substrate.

  16. 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

  17. 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

  18. 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

  19. 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

  20. Earthquakes in Alaska

    USGS Publications Warehouse

    Haeussler, Peter J.; Plafker, George

    1995-01-01

    Earthquake risk is high in much of the southern half of Alaska, but it is not the same everywhere. This map shows the overall geologic setting in Alaska that produces earthquakes. The Pacific plate (darker blue) is sliding northwestward past southeastern Alaska and then dives beneath the North American plate (light blue, green, and brown) in southern Alaska, the Alaska Peninsula, and the Aleutian Islands. Most earthquakes are produced where these two plates come into contact and slide past each other. Major earthquakes also occur throughout much of interior Alaska as a result of collision of a piece of crust with the southern margin.

  1. 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

  2. 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.

  3. Splay faults and tsunamigenic sources across the continental shelf from 1964 great Alaska earthquake

    NASA Astrophysics Data System (ADS)

    Liberty, L. M.; Haeussler, P. J.; Moeller, M.

    2013-12-01

    Using tsunami run up, seismic reflection and bathymetric data, we identify tsunamigenic sea floor ruptures that resulted from the 1964 Great Alaska earthquake. These sea floor lineaments are rooted in megathrust splay faults that appear across the 500-km wide Gulf of Alaska continental shelf. Based on estimated tsunami travel times, we identify two splay faults that produced 5-10 m wave heights in the coastal town of Seward and remote settlements along the Kenai Peninsula. These faults splay from the megathrust along the trailing edge of the subducted Yakutat terrane that is sandwiched between the Pacific and North American plates. Duplexing along the megathrust likely transferred lateral motion along the decollement to vertical splay fault motion that resulted in multi-meter sea floor uplifts. We identify the Cape Cleare fault as the source of the earliest tsunami arrival for Seward, Puget Bay and Whidbey Bay. Sparker seismic data, pre- and post-earthquake bathymetry and crustal seismic data characterize the along-strike Holocene motion on this 70-km long fault that parallels the Patton Bay fault that ruptured on nearby Montague Island. We define a strand of the Middleton Island fault system as the source of the second arrival in Puget and Whidbey Bays and the earliest tsunami source on Middleton Island and other sites in the eastern Gulf of Alaska. Sea floor displacements of more than 20 m suggest both of these faults have repeatedly ruptured during Holocene earthquakes. Additionally, we identify a series of active thrust faults along the length of the Gulf of Alaska to Kodiak Island that likely initiated tsunami waves from smaller sea floor displacements. Sea floor offsets and splay faults that are mapped along the length of the continental shelf suggest Holocene coseismic rupture patterns are not reflected in interseismic GPS measurements along the Kenai Peninsula, but are consistent with seismic, tsunami, and geodetic measurements from the 1964 earthquake

  4. 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.

  5. 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

  6. Optimising a hydrostatic ocean model for long-term climate runs of glacier-fjord dynamics

    NASA Astrophysics Data System (ADS)

    Siegfried, Merten; Burchard, Hans

    2017-04-01

    Glacier-fjord systems in Greenland contribute substantially to the total ice discharge via submarine melting and calving. Especially in South East Greenland, where warm saline water from the Atlantic enters deep narrow fjords at the bottom, melt und calving rates of marine terminating glaciers are high. The subglacial discharge of fresh and cold water at the glacier's grounding line drives a buoyant plume, which turbulently rises up. Due to entrainment of ambient warm Atlantic water, the higher thermal forcing causes drastically increased submarine melting and induces a circulation in the fjord. Beside this buoyant plume, pycnocline displacements and stratification profiles for temperature and salinity at the fjord's mouth as well as bathymetry, winds and tides are relevant to fjord dynamics. We investigate the long-term response of generic glacier-fjord pairs to climate change varying bathymetry and external forcings. In the end, a fjord model coupled to a comprehensive ice-sheet model of intermediate complexity running for up to thousand years is to be developed. Therefore, we examine the fjord dynamics applying the hydrostatic General Estuarine Circulation Model (GETM). For the sake of efficiency (I) across-fjord effects are neglected by modelling only in along-fjord direction and (II) a vertically adaptive grid is employed requiring less vertical layers. A modified plume model including a melt rate parameterisation has been implemented to handle non-hydrostatic effects appearing at the glacier front due to highly buoyant fresh subglacial discharge. Further, the shifting of the grounding line changes the bathymetry at the glacier front and thereby affects the submarine melt rate. We resolve this with a newly implemented horizontally adaptive grid following the glacier's movement. We present implementation details of our modified plume model and compare the output of our optimised hydrostatic model with non-hydrostatic model results near the glacier front

  7. 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.

  8. 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.

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

    USGS Publications Warehouse

    Jones, Benjamin M.; Baughman, Carson; Romanovsky, Vladimir E.; Parsekian, Andrew D.; Babcock, Esther; Stephani, Eva; 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

  10. A new satellite-derived glacier inventory for Western Alaska

    NASA Astrophysics Data System (ADS)

    Le Bris, Raymond; Frey, Holger; Paul, Frank; Bolch, Tobias

    2010-05-01

    Glaciers and ice caps are essential components of studies related to climate change impact assessment. Glacier inventories provide the required baseline data to perform the related analysis in a consistent and spatially representative manner. In particular, the calculation of the current and future contribution to global sea-level rise from heavily glacierized regions is a major demand. One of the regions, where strong mass losses and geometric changes of glaciers have been observed recently is Alaska. Unfortunately, the digitally available data base of glacier extent is quite rough and based on rather old maps from the 1960s. Accordingly, the related calculations and extrapolations are imprecise and an updated glacier inventory is urgently required. Here we present first results of a new glacier inventory for Western Alaska that is prepared in the framework of the ESA project GlobGlacier and is based on freely available orthorectified Landsat TM and ETM+ scenes from USGS. The analysed region covers the Tordrillo, Chigmit and Chugach Mts. as well as the Kenai Peninsula. In total, 8 scenes acquired between 2002 and 2009 were used covering c. 20.420 km2 of glaciers. All glacier types are present in this region, incl. outlet glaciers from icefields, glacier clad volcanoes, and calving glaciers. While well established automated glacier mapping techniques (band rationing) are applied to map clean and slightly dirty glacier ice, many glaciers are covered by debris or volcanic ash and outlines need manual corrections during post-processing. Prior to the calculation of drainage divides from DEM-based watershed analysis, we performed a cross-comparative analysis of DEMs from USGS, ASTER (GDEM) and SRTM 1 for Kenai Peninsula. This resulted in the decision to use the USGS DEM for calculating the drainage divides and most of the topographic inventory parameters, and the more recent GDEM to derive minimum elevation for each glacier. A first statistical analysis of the results

  11. Complete spatiotemporal freshwater flux budget for a major Greenland glacier-fjord system

    NASA Astrophysics Data System (ADS)

    Moon, Twila; Sutherland, David; Carroll, Dustin; Kehrl, Laura; Straneo, Fiamma; Felikson, Denis

    2017-04-01

    Freshwater flux from ice sheet mass loss raises global sea level, influences large-scale ocean circulation and stratification, and affects biological systems. Freshwater flux in glacial fjords comes from several sources: ice sheet surface melt discharged subglacially at the glacial termini, terrestrial runoff, submarine terminus melt, and melt from icebergs throughout the fjord (here, including icebergs, bergy bits, and melánge). Melt from icebergs is poorly constrained; previous efforts use limited-footprint satellite images and fail to distinguish iceberg freshwater flux from other melt sources. We have developed a new method, combining in situ and remote sensing observations with a parameterized iceberg melt model and climate reanalysis data, to calculate freshwater flux from icebergs and create a spatiotemporally complete fjord freshwater budget. Here, we apply this method to Sermilik Fjord, a major glacier-fjord system in southeast Greenland. We generate complete freshwater budgets for summer and winter periods during 2008-2013 as well as mean monthly estimates of iceberg freshwater flux over a full year. Along with this enhanced understanding of iceberg freshwater flux across time, our estimates also spatially resolve meltwater flux across the full water depth of the fjord. We find that more than 70% of iceberg melt production occurs below 10 m depth. We also compare iceberg melt flux to other freshwater sources, demonstrating that iceberg melt dominates freshwater production. Our work provides the first calculation of iceberg freshwater flux across the full fjord water depth, estimates the first complete freshwater budget for a major Greenland glacier-fjord system, and provides monthly to interannual comparisons across freshwater sources. Ultimately, these results provide a path forward in accurately representing freshwater flux, including iceberg melt production, in large-scale climate models.

  12. 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.

  13. 7 CFR 272.7 - Procedures for program administration in Alaska.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Census Area, the city of Nenana; and Skwentna in the Matanuska-Susitna Borough. In the Valdez-Cordova... Valdez-Cordova Census Area; all places in Kenai Peninsula Borough that are on the Kenai Peninsula...

  14. 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.

  15. 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…

  16. 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…

  17. 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…

  18. 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.

  19. Building a DNA barcode library of Alaska's non-marine arthropods.

    PubMed

    Sikes, Derek S; Bowser, Matthew; Morton, John M; Bickford, Casey; Meierotto, Sarah; Hildebrandt, Kyndall

    2017-03-01

    Climate change may result in ecological futures with novel species assemblages, trophic mismatch, and mass extinction. Alaska has a limited taxonomic workforce to address these changes. We are building a DNA barcode library to facilitate a metabarcoding approach to monitoring non-marine arthropods. Working with the Canadian Centre for DNA Barcoding, we obtained DNA barcodes from recently collected and authoritatively identified specimens in the University of Alaska Museum (UAM) Insect Collection and the Kenai National Wildlife Refuge collection. We submitted tissues from 4776 specimens, of which 81% yielded DNA barcodes representing 1662 species and 1788 Barcode Index Numbers (BINs), of primarily terrestrial, large-bodied arthropods. This represents 84% of the species available for DNA barcoding in the UAM Insect Collection. There are now 4020 Alaskan arthropod species represented by DNA barcodes, after including all records in Barcode of Life Data Systems (BOLD) of species that occur in Alaska - i.e., 48.5% of the 8277 Alaskan, non-marine-arthropod, named species have associated DNA barcodes. An assessment of the identification power of the library in its current state yielded fewer species-level identifications than expected, but the results were not discouraging. We believe we are the first to deliberately begin development of a DNA barcode library of the entire arthropod fauna for a North American state or province. Although far from complete, this library will become increasingly valuable as more species are added and costs to obtain DNA sequences fall.

  20. 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

  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. Preliminary validation of WRF model in two Arctic fjords, Hornsund and Porsanger

    NASA Astrophysics Data System (ADS)

    Aniskiewicz, Paulina; Stramska, Małgorzata

    2017-04-01

    Our research is focused on development of efficient modeling system for arctic fjords. This tool should include high-resolution meteorological data derived using downscaling approach. In this presentation we have focused on modeling, with high spatial resolution, of the meteorological conditions in two Arctic fjords: Hornsund (H), located in the western part of Svalbard archipelago and Porsanger (P) located in the coastal waters of the Barents Sea. The atmospheric downscaling is based on The Weather Research and Forecasting Model (WRF, www.wrf-model.org) with polar stereographic projection. We have created two parent domains with grid point distances of about 3.2 km (P) and 3.0 km (H) and with nested domains (almost 5 times higher resolution than parent domains). We tested what is the impact of the spatial resolution of the model on derived meteorological quantities. For both fjords the input topography data resolution is 30 sec. To validate the results we have used meteorological data from the Norwegian Meteorological Institute for stations Lakselv (L) and Honningsvåg (Ho) located in the inner and outer parts of the Porsanger fjord as well as from station in the outer part of the Hornsund fjord. We have estimated coefficients of determination (r2), statistical errors (St) and systematic errors (Sy) between measured and modelled air temperature and wind speed at each station. This approach will allow us to create high resolution spatially variable meteorological fields that will serve as forcing for numerical models of the fjords. We will investigate the role of different meteorological quantities (e. g. wind, solar insolation, precipitation) on hydrohraphic processes in fjords. 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. This work was also funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support comes from the

  3. Increased glacier runoff enhances the penetration of warm Atlantic Water into a large Greenland fjord

    NASA Astrophysics Data System (ADS)

    Sole, Andrew; Payne, Anthony; Nienow, Peter; Christoffersen, Poul; Cottier, Finlo; Inall, Mark

    2013-04-01

    The retreat and acceleration of Greenland's marine-terminating outlet glaciers have been linked to ocean warming. However the mechanisms which control the transmission of this warming along fjords towards the glacier termini remain poorly understood. Here we aim to elucidate observed changes in water properties in Kangerdlugssuaq Fjord (KF), east Greenland, between 1993 and 2004 using the Bergen Ocean Model (BOM). Model outputs are compared with observed potential temperature, salinity and velocity data to determine the principal controls on heat transport within KF. The BOM includes wind, tidal and glacier runoff forcing and is able to replicate observed temperature and salinity profiles. Model results describe a robust four-layer estuarine flow, consisting of two distinct circulations. The shallow circulation (0 - ˜60 m) is forced by surface wind stress and to a lesser extent supraglacial runoff, while the intermediate circulation (˜60 - 500 m) is driven by runoff discharged into the fjord subglacially. AtlanticWater (AW) and warm Polar Surface Water (PSWw) are drawn into the fjord by the intermediate and shallow circulation cells respectively, in a pattern consistent with observations, and AW reaches Kangerdlugssuaq Glacier (at the fjord head) over a single summer. Along-fjord heat transport towards KG increases significantly with both glacier runoff and coastal water temperature. A doubling of glacier runoff produces a 29 % (48 %) amplification of mean annual (summer) heat transport towards the KG terminus. Our model shows, in agreement with observations, that maximum submarine melt rates occur when AW and PSWw are present at the fjord mouth and, crucially, glacier runoff is also high. Rising ice sheet runoff therefore increases the sensitivity of KG (and other Greenland marine-terminating glaciers) to ocean warming.

  4. 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.

  5. Gravity and Magnetic Anomaly Interpretations and 2.5D Cross-Section Models over the Border Ranges Fault System and Aleutian Subduction Zone, Alaska

    NASA Astrophysics Data System (ADS)

    Mankhemthong, N.; Doser, D. I.; Baker, M. R.; Kaip, G.; Jones, S.; Eslick, B. E.; Budhathoki, P.

    2011-12-01

    Quaternary glacial covers and lack of dense geophysical data on the Kenai Peninsula cause a location and geometry of the Border Ranges fault system (BRFS) within a recent forearc-accretionary boundary of Aleutian subduction zone in southern Alaska are unclear. Using new ~1,300 gravity collections within the Anchorage and Kenai Peninsula regions complied with prior 1997 gravity and aeromagnetic data help us better imaging these fault and the subduction structures. Cook Inlet forearc basin is corresponded by deep gravity anomaly lows; basin boundaries are characterized by a strong gravity gradient, where are considered to be traces of Border Ranges fault system on the east and Castle Mountain and Bruin Bay fault system on the west and northwest of the forearc basin respectively. Gravity anomaly highs over accreted rocks generally increase southeastward to the Aleutian trench, but show a gravity depression over the Kenai Mountains region. The lineament between gravity high and low in the same terrenes over the Kenai Peninsula is may be another evidence to determine the Southern Edge of the Yakutat Microplate (SEY) as inferred by Eberhart-Phillips et al. (2006). Our 2.5-D models illustrate the main fault of the BRFS dips steeply toward the west with a downslip displacement. Gravity and Magnetic anomaly highs, on the east of the BRFS, probably present a slice of the ultramafic complex emplaced by faults along the boundary of the forearc basin and accretionary wedge terranes. Another magnetic high beneath the basin in the southern forearc basin support a serpentiznied body inferred by Saltus et al. (2001), with a decreasing size toward the north. Regional density-gravity models show the Pacific subducting slab beneath the foreacre-arc teranes with a gentle and flatted dip where the subducting plate is located in north of SEY and dips more steeply where it is located on the south of SEY. The gravity depression over the accreted terrene can be explained by a density low

  6. Seasonal dynamics of meroplankton in a high-latitude fjord

    NASA Astrophysics Data System (ADS)

    Michelsen, Helena Kling; Svensen, Camilla; Reigstad, Marit; Nilssen, Einar Magnus; Pedersen, Torstein

    2017-04-01

    Knowledge on the seasonal timing and composition of pelagic larvae of many benthic invertebrates, referred to as meroplankton, is limited for high-latitude fjords and coastal areas. We investigated the seasonal dynamics of meroplankton in the sub-Arctic Porsangerfjord (70°N), Norway, by examining their seasonal changes in relation to temperature, chlorophyll a and salinity. Samples were collected at two stations between February 2013 and August 2014. We identified 41 meroplanktonic taxa belonging to eight phyla. Multivariate analysis indicated different meroplankton compositions in winter, spring, early summer and late summer. More larvae appeared during spring and summer, forming two peaks in meroplankton abundance. The spring peak was dominated by cirripede nauplii, and late summer peak was dominated by bivalve veligers. Moreover, spring meroplankton were the dominant component in the zooplankton community this season. In winter, low abundances and few meroplanktonic taxa were observed. Timing for a majority of meroplankton correlated with primary production and temperature. The presence of meroplankton in the water column through the whole year and at times dominant in the zooplankton community, suggests that they, in addition to being important for benthic recruitment, may play a role in the pelagic ecosystem as grazers on phytoplankton and as prey for other organisms.

  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.

  8. Diversity of retrievable heterotrophic bacteria in Kongsfjorden, an Arctic fjord.

    PubMed

    Sinha, Rupesh Kumar; Krishnan, Kottekkatu Padinchati; Hatha, Ammanamveetil Abdulla Mohamed; Rahiman, Mujeeb; Thresyamma, Divya David; Kerkar, Savita

    The diversity and abundance of retrievable pelagic heterotrophic bacteria in Kongsfjorden, an Arctic fjord, was studied during the summer of 2011 (June, August, and September). Retrievable bacterial load ranged from 10(3) to 10(7)CFUL(-1) in June, while it was 10(4)-10(6)CFUL(-1) in August and September. Based on 16S rRNA gene sequence similarities, a higher number of phylotypes was observed during August (22 phylotypes) compared to that during June (6 phylotypes) and September (12 phylotypes). The groups were classified into four phyla: Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Bacteroidetes was represented only by a single member Leewenhoekiella aequorea during the three months and was dominant (40%) in June. However, this dominance changed in August to a well-known phytopathogenic species Rhodococcus fascians (32%), which could be a result of decrease in the phytoplankton biomass following the secondary bloom. It is the first report of Halomonas titanicae isolation from the Arctic waters. It showed an increase in its abundance with the intrusion of Atlantic water into Kongsfjorden. Increased abundance of Psychrobacter species in the late summer months coincided with the presence of cooler waters. Thus, the composition and function of heterotrophic bacterial community was fundamentally different in different months. This could be linked to the changes in the water masses and/or phytoplankton bloom dynamics occurring in Arctic summer. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  9. Dynamic jamming fronts in iceberg-choked fjords

    NASA Astrophysics Data System (ADS)

    Peters, Ivo; Amundson, Jason; Cassotto, Ryan; Fahnestock, Mark; Darnell, Kristopher; Truffer, Martin; Zhang, Wendy

    2015-03-01

    During summertime at the glacier terminus at Jakobshavn Isbræ, Greenland, calving events are followed by rapid motion in the ice mélange in front of the terminus. Understanding the dynamics of ice mélange is important because it acts as a resisting force to calving events. We analyze this motion using time-lapse photography and terrestrial radar images. Large calving events last for approximately 5 minutes, during which ~1014 J of potential energy is released. Motion in the ice mélange quickly spreads out over at least 16 km down the fjord, and relaxes in about 1 hour. The ice mélange can be viewed as a dense granular system, which is packed close to the jamming point. A jammed ice mélange resists expansion of the glacier terminus much more strongly and reduces iceberg calving, which may therefore play a significant role in glacier evolution. In our images, we observe dynamic jamming fronts, which propagate one order of magnitude faster than the instantaneous speed of the calving iceberg. From the ratio between the speed of the front and the calving iceberg we calculate a compaction that agrees with estimated compaction that we observe directly.

  10. Spatial diastereomer patterns of hexabromocyclododecane (HBCD) in a Norwegian fjord.

    PubMed

    Haukås, Marianne; Hylland, Ketil; Berge, John Arthur; Nygård, Torgeir; Mariussen, Espen

    2009-11-01

    Hexabromocyclododecane (HBCD) is the third most used brominated flame retardant globally, and has been found widely distributed in the environment. The present study reports concentrations and spatial patterns of alpha, beta and gamma-HBCD in a contaminated Norwegian fjord. Intertidal surface sediment and selected species from the marine food web were sampled at five locations in increasing distance from a known point source of HBCD. All sediment and biota samples were analyzed for the three HBCD diastereomers by liquid chromatography and mass spectrometry (LC/MS). The results demonstrated a HBCD gradient with decreasing concentrations at increasing distance from the point source in sediment and sedentary species, but less so in the species with large feeding ranges. Mean concentrations of Sigma HBCD at the closest/most remote locations relative to the point source were 9000/300 ng g(-1) TOC in sediment and 150/90 ng g(-1) lw in the species with largest feeding range (great black-backed gull). The HBCD diastereomer patterns were similar for each of the matrices (sediment, organisms) independent of distance from the source, indicating no difference in environmental partitioning between the diastereomers. However, the concentration ratio of diastereomers in each matrix ranged from 3:1:10 (alpha:beta:gamma) in the sediments to 55:1 (alpha:gamma) in the highest trophic level species, suggesting diastereomer-specific bioaccumulation in the organisms.

  11. 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

  12. Increased glacier runoff enhances the penetration of warm Atlantic water into a large Greenland fjord

    NASA Astrophysics Data System (ADS)

    Sole, A. J.; Payne, A. J.; Nienow, P. W.; Christoffersen, P.; Cottier, F. R.; Inall, M. E.

    2012-11-01

    The retreat and acceleration of Greenland's marine-terminating outlet glaciers have been linked to ocean warming. However the mechanisms which control the transmission of this warming along fjords towards the glaciers remain poorly understood. The aim of this paper is to elucidate observed changes in water properties in Kangerdlugssuaq Fjord (KF), East Greenland using the Bergen Ocean Model (BOM). Model outputs are compared with observed potential temperature, salinity and velocity data to determine the principal controls on heat transport within KF and to estimate resulting submarine ice front melt rates of Kangerdlugssuaq Glacier (KG). The BOM includes wind, tidal and glacier runoff forcing and is able to replicate observed temperature and salinity profiles. Model results describe a robust four-layer estuarine flow, consisting of two distinct circulations. The shallow circulation (0-~ 60 m) is forced by surface wind stress and to a lesser extent supraglacial runoff, while the intermediate circulation (~ 60-500 m) is driven by runoff discharged into the fjord subglacially. Atlantic Water (AW) and warm Polar Surface Water (PSWw) are drawn into the fjord by the intermediate and shallow circulation cells respectively, in a pattern consistent with observations, and AW reaches KG over a single summer. Along-fjord heat transport towards KG increases significantly with both glacier runoff and coastal water temperature. A doubling of glacier runoff produces a 29% (48%) amplification of mean annual (summer) heat transport towards the KG terminus, increasing estimated mean annual (summer) submarine melt rates from 211 to 273 (842 to 1244) m yr-1. In contrast, heat transport towards KG in the surface ~ 60 m of the fjord decreases with rising glacier runoff because the enhanced down-fjord component of the intermediate circulation interferes with the up-fjord part of the shallow circulation. Thus, as ice sheet runoff increases, KG's dynamic response to oceanic forcing will

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Genome Sequence of Streptomyces sp. H-KF8, a Marine Actinobacterium Isolated from a Northern Chilean Patagonian Fjord

    PubMed Central

    Undabarrena, Agustina; Ugalde, Juan Antonio; Castro-Nallar, Eduardo; Seeger, Michael

    2017-01-01

    ABSTRACT Streptomyces sp. H-KF8 is a fjord-derived marine actinobacterium capable of producing antimicrobial activity. Streptomyces sp. H-KF8 was isolated from sediments of the Comau fjord, located in the northern Chilean Patagonia. Here, we report the 7.7-Mb genome assembly, which represents the first genome of a Chilean marine actinobacterium. PMID:28183776

  18. 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.

  19. 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.

  20. Genome Sequence of Streptomyces sp. H-KF8, a Marine Actinobacterium Isolated from a Northern Chilean Patagonian Fjord.

    PubMed

    Undabarrena, Agustina; Ugalde, Juan Antonio; Castro-Nallar, Eduardo; Seeger, Michael; Cámara, Beatriz

    2017-02-09

    Streptomyces sp. H-KF8 is a fjord-derived marine actinobacterium capable of producing antimicrobial activity. Streptomyces sp. H-KF8 was isolated from sediments of the Comau fjord, located in the northern Chilean Patagonia. Here, we report the 7.7-Mb genome assembly, which represents the first genome of a Chilean marine actinobacterium. Copyright © 2017 Undabarrena et al.

  1. 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

  2. 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.

  3. 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.

  4. 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 A.; 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. 

  5. 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.

  6. 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.

  7. 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

  8. Biodiversity and abundance patterns of rock encrusting fauna in a temperate fjord.

    PubMed

    Kuklinski, Piotr

    2013-01-01

    Fjords are semi-enclosed systems often with usually strong physical and chemical gradients. These gradients provide the opportunity to test the influence of various physical and chemical factors on biodiversity. However study area of this investigation, Trondheimsfjord, is a large water body where especially salinity gradient along the fjord is not well pronounced. The goal of this study was to establish within a temperate fjord a baseline identifying encrusting fauna on rocks and determine the factors driving changes along the length of the fjord and changing depths. There was no trend in species composition change and increase or decrease in number of species, diversity and number of individuals along the fjord. This was likely due to the relative homogeneity of both substrate (rocks) and environmental parameters. Nevertheless, the influence of fresh water inflow in the vicinity of the river mouth was apparent by the presence of characteristic brackish-water species at these locations. Multidimensional scaling analysis revealed three separate assemblages: intertidal, shallow and deep subtidal (below 50 m). Intertidal assemblages were species poor (one to 11 species) but relatively abundant (six to 2374 indiv./m(2) of rocks). Number of individuals and biomass was highest in the shallow subtidal (2059-13,587 indiv./m(2) of rocks). Overall the highest species number (45) was recorded at 50 m depth which is probably result of low competition pressure yet still relatively high nutrient concentration in comparison to shallower locations. Environmental parameters (i.e., tidal currents, wave action, salinity) change more drastically with depth than along the fjord and these changes are the major driving forces in shaping encrusting assemblages in Trondheimsfjord.

  9. 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.

  10. 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.

  11. Comparison of climate related changes in two Arctic fjords, Hornsund and Porsanger

    NASA Astrophysics Data System (ADS)

    Aniskiewicz, Paulina; Stramska, Małgorzata

    2017-04-01

    In the Arctic zone the climate change is amplified in comparison to globally averaged trends, and the observed trends are variable spatially. Our research is focused on two Artic fjords: Porsanger and Horsund. Porsanger fjord is located in the coastal waters of the Barents Sea. Hornsund is one of fjords located in the western part of Svalbard archipelago. In this presentation we have used data provided by the Norwegian Meteorological Institute for three meteorological stations. Two of them are located in the Porsanger fjord (Lakselv - in the inner part, Honningsvåg - in the outer zone). The third station provides data from the Hornsund fjord. Using these data we have estimated the 33-year trends (1983-2015) of air temperature and relative humidity in each station using linear regression analysis (statistically significant at 95In the inner part of the Porsanger fjord (Lakselv) the multiyear trend of increasing annual mean air temperature has been estimated at 0.006°C per year. The monthly trends were statistically significant in May, September and November. The strongest seasonal warming has been observed in spring and autumn. The trends of increasing annual mean humidity was about 0.2In Hornsund the air temperature trend (0.2°C per year) is significantly larger than in Porsanger. The trends of air temperature were statistically significant for eight months (except March, April, June and July) and three seasons (besides spring). The trends of relative humidity were not statistically significant. Thanks to this research we can discuss how atmospheric conditions and climate related trends change in time and seasons of the year in two different Arctic regions. 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. This work was also funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX). Partial support comes from the Institute of Oceanology (IO

  12. 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.

  13. 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

  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. Paleoseismic potential of sublacustrine landslide records in a high-seismicity setting (south-central Alaska)

    USGS Publications Warehouse

    Praet, Nore; Moernaut, Jasper; Van Daele, Maarten; Boes, Evelien; Haeussler, Peter J.; Strupler, Michael; Schmidt, Sabine; Loso, Michael G.; De Batist, Marc

    2017-01-01

    Sublacustrine landslide stratigraphy is considered useful for quantitative paleoseismology in low-seismicity settings. However, as the recharging of underwater slopes with sediments is one of the factors that governs the recurrence of slope failures, it is not clear if landslide deposits can provide continuous paleoseismic records in settings of frequent strong shaking. To test this, we selected three lakes in south-central Alaska that experienced a strong historical megathrust earthquake (the 1964 Mw9.2 Great Alaska Earthquake) and exhibit high sedimentation rates in their main basins (0.2 cm yr-1 -1.0 cm yr-1). We present high-resolution reflection seismic data (3.5 kHz) and radionuclide data from sediment cores in order to investigate factors that control the establishment of a reliable landslide record. Seismic stratigraphy analysis reveals the presence of several landslide deposits in the lacustrine sedimentary infill. Most of these landslide deposits can be attributed to specific landslide events, as multiple landslide deposits sourced from different lacustrine slopes occur on a single stratigraphic horizon. We identify numerous events in the lakes: Eklutna Lake proximal basin (14 events), Eklutna Lake distal basin (8 events), Skilak Lake (7 events) and Kenai Lake (7 events). The most recent event in each basin corresponds to the historic 1964 megathrust earthquake. All events are characterized by multiple landslide deposits, which hints at a regional trigger mechanism, such as an earthquake (the synchronicity criterion). This means that the landslide record in each basin represents a record of past seismic events. Based on extrapolation of sedimentation rates derived from radionuclide dating, we roughly estimate a mean recurrence interval in the Eklutna Lake proximal basin, Eklutna Lake distal basin, Skilak Lake and Kenai Lake, at ~ 250 yrs, ~ 450 yrs, ~ 900 yrs and ~ 450 yrs, respectively. This distinct difference in recording can be explained by variations

  16. 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

  17. 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.

  18. 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.

  19. South Central Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Glacial silt along the Copper River in Alaska is picked up by the wind and carried out over the Gulf of Alaska. This true-color MODIS image from October 26, 2001, shows a large gray dust plume spreading out over the Gulf. West of the Copper River Delta, Cook Inlet is full of sediment.

  20. Tourism in rural Alaska

    Treesearch

    Katrina Church-Chmielowski

    2007-01-01

    Tourism in rural Alaska is an education curriculum with worldwide relevance. Students have started small businesses, obtained employment in the tourism industry and gotten in touch with their people. The Developing Alaska Rural Tourism collaborative project has resulted in student scholarships, workshops on website development, marketing, small...

  1. 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

  2. Mass-mortality of guillemots (Uria aalge) in the Gulf of Alaska in 1993

    USGS Publications Warehouse

    Piatt, John F.; van Pelt, Thomas I.

    1997-01-01

    During the first six months of 1993, about 3500 dead and moribund guillemots (Uria aalge) were observed throughout the northern Gulf of Alaska coast (ca 1800 km range). Mortality peaked during March. Highest numbers were observed in western Prince William Sound and along the south coast of the Kenai Peninsula. Large flocks of live guillemots gathered in nearshore waters, in contrast to most winters when guillemots reside offshore. Most guillemots recovered were extremely emaciated (ca 60% of normal weight) and sub-adult (80%). Based on carcass deposition and persistence experiments, we calculate that about 10 900 birds eventually came ashore on beaches that were surveyed. Even if most birds killed made it to shore, only a fraction of beaches in the Gulf of Alaska were surveyed and we estimate that a minimum total of 120 000 guillemots died. Results of other investigations on potential causes of mortality (biotoxins, pathogens, parasites, metals, etc.) were either negative or inconclusive, and necropsies lead us to believe that starvation was the proximate cause of death. Reduced food availability could have been related to anomalous sea conditions found during the prolonged 1990–1995 El Niño-Southern Oscillation event.

  3. 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.

  4. Alaska Problem Resource Manual: Alaska Future Problem Solving Program. Alaska Problem 1985-86.

    ERIC Educational Resources Information Center

    Gorsuch, Marjorie, Ed.

    "Alaska's Image in the Lower 48," is the theme selected by a Blue Ribbon panel of state and national leaders who felt that it was important for students to explore the relationship between Alaska's outside image and the effect of that image on the federal programs/policies that impact Alaska. An overview of Alaska is presented first in…

  5. Alaska Problem Resource Manual: Alaska Future Problem Solving Program. Alaska Problem 1985-86.

    ERIC Educational Resources Information Center

    Gorsuch, Marjorie, Ed.

    "Alaska's Image in the Lower 48," is the theme selected by a Blue Ribbon panel of state and national leaders who felt that it was important for students to explore the relationship between Alaska's outside image and the effect of that image on the federal programs/policies that impact Alaska. An overview of Alaska is presented first in…

  6. 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).

  7. Seasonal sea surface and sea ice signal in the fjords of Eastern Greenland from CryoSat-2 SARin altimetry

    NASA Astrophysics Data System (ADS)

    Abulaitijiang, Adili; Baltazar Andersen, Ole; Stenseng, Lars

    2014-05-01

    Cryosat-2 offers the first ever possibility to perform coastal altimetric studies using SAR-Interferometry. This enabled qualified measurements of sea surface height (SST) in the fjords in Greenland. Scoresbysund fjord on the east coast of Greenland is the largest fjord in the world which is also covered by CryoSat-2 SAR-In mask making it a good test region. Also, the tide gauge operated by DTU Space is sitting in Scoresbysund bay, which provides solid ground-based sea level variation records throughout the year. We perform an investigation into sea surface height variation since the start of the Cryosat-2 mission using SAR-In L1B data processed with baseline B processing. We have employed a new develop method for projecting all SAR-In observations in the Fjord onto a centerline up the Fjord. Hereby we can make solid estimates of the annual and (semi-) annual signal in sea level/sea ice freeboard within the Fjord. These seasonal height variations enable us to derive sea ice freeboard changes in the fjord from satellite altimetry. Derived sea level and sea-ice freeboard can be validated by comparison with the tide gauge observations for sea level and output from the Microwave Radiometer derived observations of sea ice freeboard developed at the Danish Meteorological Institute.

  8. Gap Winds in a Fjord: Howe Sound, British Columbia.

    NASA Astrophysics Data System (ADS)

    Jackson, Peter L.

    1993-01-01

    Gap, outflow, or Squamish wind, is the cold low level seaward flow of air through fjords which dissect the coastal mountain barrier of northwestern North America. These flows, occurring mainly during winter, can be strong, threatening safety, economic activity and comfort. Howe Sound gap winds were studied using a combination of observations and several types of models. Observations of winds in Howe Sound showed that gap wind strength varied considerably along the channel, across the channel and vertically. Generally, winds increase down the channel, are strongest along the eastern side, and are below 1000 m depth. Observations were unable to answer all questions about gap winds due to data sparseness, particularly in the vertical direction. Therefore, several modelling approaches were used. The modelling began with a complete 3-dimensional quasi-Boussinesq model (CSU RAMS) and ended with the creation and testing of models which are conceptually simpler, and more easily interpreted and manipulated. A gap wind simulation made using RAMS was shown to be mostly successful by statistical evaluation compared to other mesoscale simulations, and by visual inspection of the fields. The RAMS output, which has very high temporal and spatial resolution, provided much additional information about the details of gap flow. In particular, RAMS results suggested a close analogy between gap wind and hydraulic channel flow, with hydraulic features such as supercritical flow and hydraulic jumps apparent. These findings imply gap wind flow could potentially be represented by much simpler models. The simplest possible models containing pressure gradient, advection and friction but not incorporating hydraulic effects, were created, tested, and found lacking. A hydraulic model, which in addition incorporates varying gap wind height and channel geometry, was created and shown to successfully simulate gap winds. Force balance analysis from RAMS and the hydraulic model showed that pressure

  9. 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.

  10. Iceberg meltwater fluxes dominate the freshwater budget in Greenland's iceberg-congested glacial fjords

    NASA Astrophysics Data System (ADS)

    Enderlin, Ellyn M.; Hamilton, Gordon S.; Straneo, Fiammetta; Sutherland, David A.

    2016-11-01

    Freshwater fluxes from the Greenland ice sheet have increased over the last two decades due to increases in liquid (i.e., surface and submarine meltwater) and solid ice (i.e., iceberg) fluxes. To predict potential ice sheet-ocean-climate feedbacks, we must know the partitioning of freshwater fluxes from Greenland, including the conversion of icebergs to liquid (i.e., meltwater) fluxes within glacial fjords. Here we use repeat 0.5 m-resolution satellite images from two major fjords to provide the first observation-based estimates of the meltwater flux from the dense matrix of floating ice called mélange. We find that because of its expansive submerged area (>100 km2) and rapid melt rate ( 0.1-0.8 m d-1), the ice mélange meltwater flux can exceed that from glacier surface and submarine melting. Our findings suggest that iceberg melt within the fjords must be taken into account in studies of glacial fjord circulation and the impact of Greenland melt on the ocean.

  11. 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.

  12. 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.

  13. Evidence of Anomalously Low δ13C of Marine Organic Matter in an Arctic Fjord

    PubMed Central

    Kumar, Vikash; Tiwari, Manish; Nagoji, Siddhesh; Tripathi, Shubham

    2016-01-01

    Accurate estimation of relative carbon deposition (marine vs. terrestrial) is required for understanding the global carbon budget, particularly in the Arctic region, which holds disproportionate importance with respect to global carbon cycling. Although the sedimentary organic matter (SOM) concentration and its isotopic composition are important tools for such calculations, uncertainties loom over estimates provided by organic-geochemical bulk parameters. We report carbon and nitrogen concentrations and isotopes (δ13C and δ15N) of SOM at an Arctic fjord namely Kongsfjorden. We find that the bound inorganic nitrogen (ammonium attached to the clay minerals) forms a significant proportion of total nitrogen concentration (~77% in the inner fjord to ~24% in the outer part). On removing the bound nitrogen, the C/N ratio shows that the SOM in the inner fjord is made up of terrestrial carbon while the outer fjord shows mixed marine-terrestrial signal. We further show that the marine organic matter is unusually more depleted in 13C (~−24‰) than the terrestrial organic matter (~−22.5‰). This particular finding also helps explain high δ13C values of SOM as noted by earlier studies in central Arctic sediments despite a high terrestrial contribution. PMID:27827457

  14. Evidence of Anomalously Low δ13C of Marine Organic Matter in an Arctic Fjord

    NASA Astrophysics Data System (ADS)

    Kumar, Vikash; Tiwari, Manish; Nagoji, Siddhesh; Tripathi, Shubham

    2016-11-01

    Accurate estimation of relative carbon deposition (marine vs. terrestrial) is required for understanding the global carbon budget, particularly in the Arctic region, which holds disproportionate importance with respect to global carbon cycling. Although the sedimentary organic matter (SOM) concentration and its isotopic composition are important tools for such calculations, uncertainties loom over estimates provided by organic-geochemical bulk parameters. We report carbon and nitrogen concentrations and isotopes (δ13C and δ15N) of SOM at an Arctic fjord namely Kongsfjorden. We find that the bound inorganic nitrogen (ammonium attached to the clay minerals) forms a significant proportion of total nitrogen concentration (~77% in the inner fjord to ~24% in the outer part). On removing the bound nitrogen, the C/N ratio shows that the SOM in the inner fjord is made up of terrestrial carbon while the outer fjord shows mixed marine-terrestrial signal. We further show that the marine organic matter is unusually more depleted in 13C (~‑24‰) than the terrestrial organic matter (~‑22.5‰). This particular finding also helps explain high δ13C values of SOM as noted by earlier studies in central Arctic sediments despite a high terrestrial contribution.

  15. 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. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  16. 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

  17. Climate related trends and meteorological conditions in European Arctic region - Porsanger fjord, Norway

    NASA Astrophysics Data System (ADS)

    Cieszyńska, Agata; Stramska, Małgorzata

    2017-04-01

    Climate change has significant effect on the Arctic environment, where global trends are amplified. In this study, we have focused on the Porsanger fjord, located in European Arctic in the coastal region of the Barents Sea. We have analyzed climate related trends and meteorological condititions in the area of interest. Meteorological data included wind speed and direction, air temperature (AT) and precipitation from Era-Interim reanalysis (1986-2015) and local observations (1996-2015) from Lakselv (L, fjord's head area) and Honningsvaag (H - fjord's exit area). Our results confirm that this region is undergoing climate change related warming, which is indicated by rising air temperatures. Based on long-term reanalysis data, estimated trends for air temperature (AT) in Porsanger fjord are: 0.0536 °C year-1 at fjord's exit and 0.0428 °C year-1 at fjord's head. The results show that climate change does not seem to have a significant effect on long-term changes of wind speed and precipitation in the Porsanger fjord. Statistical analysis underlined significant spatial variability of meteorological conditions inside the fjord. For example, there are large differences in the annual cycle of AT with monthly mean January and July values of -8.4 and 12.6 °C in L and -2.5 and 10.1 °C in H. Dominant wind directions in Lakselv are S and SSE, while in Honningsvaag S and SSW directions prevail. Strong wind events (above 12 m s-1) are more frequent in H than in L. Annual cycle is characterized by stronger winds in winter and seasonality of wind direction. Precipitation for a given location can change by about 50% between years and varies spatially. Synoptic scale and within day variability are extremely intense in the area of interest. Air temperature and wind speed and direction can change dramatically in hours. In addition, regular patterns of the daily cycle of AT have different intensity in L and H. It is interesting to note that in spring/summer season, the daily cycle of

  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. Containing...

  19. 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- ...

  20. UAFSmoke Modeling in Alaska

    NASA Astrophysics Data System (ADS)

    Stuefer, M.; Grell, G.; Freitas, S.; Newby, G.

    2008-12-01

    Alaska wildfires have strong impact on air pollution on regional Arctic, Sub-Arctic and even hemispheric scales. In response to a high number of wildfires in Alaska, emphasis has been placed on developing a forecast system for wildfire smoke dispersion in Alaska. We have developed a University of Alaska Fairbanks WRF/Chem smoke (UAFSmoke) dispersion system, which has been adapted and initialized with source data suitable for Alaska. UAFSmoke system modules include detection of wildfire location and area using Alaska Fire Service information and satellite remote sensing data from the MODIS instrument. The fire emissions are derived from above ground biomass fuel load data in one-kilometer resolution. WRF/Chem Version 3 with online chemistry and online plume dynamics represents the core of the UAFSmoke system. Besides wildfire emissions and NOAA's Global Forecast System meteorology, WRF/Chem initial and boundary conditions are updated with anthropogenic and sea salt emission data from the Georgia Institute of Technology-Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) Model. System runs are performed at the Arctic Region Supercomputing Center's Sun Opteron cluster "Midnight". During the 2008 fire season once daily UAFSmoke runs were presented at a dedicated webpage at http://smoke.arsc.edu. We present examples from these routine runs and from the extreme 2004 Alaska wildfire season.

  1. Jamming of granular ice mélange in tidewater glacial fjords

    NASA Astrophysics Data System (ADS)

    Burton, J. C.; Cassotto, R.; Amundson, J. M.; Kuo, C. C.; Dennin, M.

    2016-12-01

    In tidewater glacial fjords, the open water in front of the glacier terminus is often filled with a collection of calved iceberg fragments and sea ice. For glaciers with large calving rates, this "mélange" of ice can be jam-packed, so that the flow is mostly determined by granular interactions, in addition to underlying fjord currents. As the glacier pushes the ice mélange through the fjord, the mélange will become jammed and may potentially influence calving rates if the back-stress applied to the glacier terminus is large enough. However, the stress applied by a granular ice mélange will depend on its rheology, i.e. iceberg-iceberg contact forces, geometry, friction, etc. Here we report 2D, discrete particle simulations to model the granular mechanics of ice mélange. A polydisperse collection of particles is packed into a long channel and pushed downfjord at a constant speed, the latter derived from terrestrial radar interferometry (TRI). Each individual particle experiences viscoelastic contact forces and tangential frictional forces upon collision with another particle or channel walls. We find the two most important factors that govern the total force applied to the glacier are the geometry of the channel, and the shape of the particles. In addition, our simulated velocity fields reveal shearing margins near the fjord walls with more uniform flow in the middle of the mélange, consistent with TRI observations. Finally, we find that the magnitude of the back-stress applied to the glacier terminus can influence calving, however, the maximum back-stress is limited by the buckling of icebergs into the fjord waters, so that the stress in the quasi-2D mélange is partially determined by the thickness of the mélange layer.

  2. 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.

  3. A Sensitivity Analysis of Triggers and Mechanisms of Mass Movements in Fjords

    NASA Astrophysics Data System (ADS)

    Overeem, I.; Lintern, G.; Hill, P.

    2016-12-01

    Fjords are characterized by rapid sedimentation as they typically drain glaciated river catchments with high seasonal discharges and large sediment evacuation rates. For this reason, fjords commonly experience submarine mass movements; failures of the steep delta front that trigger tsunamis, and turbidity currents or debris flows. Repeat high-resolution bathymetric surveys, and in-situ process measurements collected in fjords in British Columbia, Canada, indicate that mass movements occur many times per year in some fjords and are more rare and of larger magnitude in other fjords. We ask whether these differences can be attributed to river discharge characteristics or to grainsize characteristics of the delivered sediment. To test our ideas, we couple a climate-driven river sediment transport model, HydroTrend, and a marine sedimentation model, Sedflux2D, to explore the triggers of submarine failures and mechanisms of subsequent turbidity and debris flows. HydroTrend calculates water and suspended sediment transport on a daily basis based on catchment characteristics, glaciated area, lakes and temperature and precipitation regime. Sedflux uses the generated river time-series to simulate delta plumes, failures and mass movements with separate process models. Model uncertainty and parameter sensitivity are assessed using Dakota Tools, which allows for a systematic exploration of the effects of river basin characteristics and climate scenarios on occurrence of hyperpycnal events, delta front sedimentation rate, submarine pore pressure, failure frequency and size, and run-out distances. Preliminary simulation results point to the importance of proglacial lakes and lakes abundance in the river basin, which has profound implications for event-based sediment delivery to the delta apex. Discharge-sediment rating curves can be highly variable based on these parameters. Distinction of turbidity currents and debris flows was found to be most sensitive to both earthquake

  4. Fjord circulation promotes significant glacier-wide submarine melting at a west Greenland tidewater glacier

    NASA Astrophysics Data System (ADS)

    Slater, Donald A.; Straneo, Fiamma; Das, Sarah B.; Nienow, Peter W.

    2017-04-01

    In recent decades, rapid change at Greenland's marine-terminating glaciers has significantly impacted the contribution of the ice sheet to sea level. While these changes have been widely linked to a warming of the ocean around Greenland, process understanding linking ocean forcing to glacier response, for example by submarine melting, remains at an early stage. The most rapid submarine melting likely occurs where buoyant plumes, initiated by subglacial discharge, rise up tidewater glacier calving fronts. Plumes have therefore received much attention, yet a plume typically occupies only a small fraction of the submerged calving front area. Thus melting within the plume itself may be a small contributor to the front-wide melting experienced by the glacier. A plume may however promote melting over a much larger area by inducing a fjord-scale circulation which, by increasing water velocities at the ice/ocean interface, can give rise to increased melting over the entire glacier face. Here we address this fjord-scale, plume-driven circulation and its impact on submarine melting by combining observations collected within 100 m of marine-terminating Saqqarliup Sermia in west Greenland with high-resolution fjord modelling using the MITgcm. Both field data and modelling show that water from the main plume flows away from the glacier as a subsurface jet, and that entrainment into this jet generates regions of fjord water recirculating back towards the glacier. The modelling further suggests that these recirculations drive elevated across-glacier water motion thereby promoting significant submarine melting over the full 4 km-width of the calving front, resulting in total melt volumes which substantially exceed those generated directly by the relatively narrow plume. Our results highlight the value of combining detailed field observations with modelling and demonstrate how the secondary fjord circulation generated by plumes may play a significant role in driving submarine

  5. 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)

  6. 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

  7. Inundation Mapping and Hazard Assessment of Tectonic and Landslide Tsunamis in Southeast Alaska

    NASA Astrophysics Data System (ADS)

    Suleimani, E.; Nicolsky, D.; Koehler, R. D., III

    2014-12-01

    The Alaska Earthquake Center conducts tsunami inundation mapping for coastal communities in Alaska, and is currently focused on the southeastern region and communities of Yakutat, Elfin Cove, Gustavus and Hoonah. This activity provides local emergency officials with tsunami hazard assessment, planning, and mitigation tools. At-risk communities are distributed along several segments of the Alaska coastline, each having a unique seismic history and potential tsunami hazard. Thus, a critical component of our project is accurate identification and characterization of potential tectonic and landslide tsunami sources. The primary tectonic element of Southeast Alaska is the Fairweather - Queen Charlotte fault system, which has ruptured in 5 large strike-slip earthquakes in the past 100 years. The 1958 "Lituya Bay" earthquake triggered a large landslide into Lituya Bay that generated a 540-m-high wave. The M7.7 Haida Gwaii earthquake of October 28, 2012 occurred along the same fault, but was associated with dominantly vertical motion, generating a local tsunami. Communities in Southeast Alaska are also vulnerable to hazards related to locally generated waves, due to proximity of communities to landslide-prone fjords and frequent earthquakes. The primary mechanisms for local tsunami generation are failure of steep rock slopes due to relaxation of internal stresses after deglaciation, and failure of thick unconsolidated sediments accumulated on underwater delta fronts at river mouths. We numerically model potential tsunami waves and inundation extent that may result from future hypothetical far- and near-field earthquakes and landslides. We perform simulations for each source scenario using the Alaska Tsunami Model, which is validated through a set of analytical benchmarks and tested against laboratory and field data. Results of numerical modeling combined with historical observations are compiled on inundation maps and used for site-specific tsunami hazard assessment by

  8. 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)

  9. Alaska geology revealed

    USGS Publications Warehouse

    Wilson, Frederic H.; Labay, Keith A.

    2016-11-09

    This map shows the generalized geology of Alaska, which helps us to understand where potential mineral deposits and energy resources might be found, define ecosystems, and ultimately, teach us about the earth history of the State. Rock units are grouped in very broad categories on the basis of age and general rock type. A much more detailed and fully referenced presentation of the geology of Alaska is available in the Geologic Map of Alaska (http://dx.doi.org/10.3133/sim3340). This product represents the simplification of thousands of individual rock units into just 39 broad groups. Even with this generalization, the sheer complexity of Alaskan geology remains evident.

  10. 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.

  11. Alaska Resource Data File, Nabesna quadrangle, Alaska

    USGS Publications Warehouse

    Hudson, Travis L.

    2003-01-01

    Descriptions of the mineral occurrences shown on the accompanying figure follow. 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.

  12. Alaska Resource Data File, Wiseman quadrangle, Alaska

    USGS Publications Warehouse

    Britton, Joe M.

    2003-01-01

    Descriptions of the mineral occurrences shown on the accompanying figure follow. 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.

  13. Alaska Resource Data File, Juneau quadrangle, Alaska

    USGS Publications Warehouse

    Barnett, John C.; Miller, Lance D.

    2003-01-01

    Descriptions of the mineral occurrences shown on the accompanying figure follow. 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.

  14. 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

  15. 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.

  16. Phytomass in southeast Alaska.

    Treesearch

    Bert R. Mead

    1998-01-01

    Phytomass tables are presented for the southeast Alaska archipelago. Average phytomass for each sampled species of tree, shrub, grass, forb, lichen, and moss in 10 forest and 4 nonforest vegetation types is shown.

  17. Hawkweed Control in Alaska

    USDA-ARS?s Scientific Manuscript database

    Several hawkweed species from Europe have escaped ornamental planting and have colonized roadsides and grasslands in south central and southeast Alaska. These plants form near monotypic stands, reducing plant diversity and decreasing pasture productivity. A replicated greenhouse study was conducted ...

  18. Susitna Glacier, Alaska

    NASA Image and Video Library

    2010-09-13

    Folds in the lower reaches of valley glaciers can be caused by powerful surges of tributary ice streams. This phenomenon is spectacularly displayed by the Sustina Glacier in the Alaska Range as seen by NASA Terra spacecraft.

  19. Malaspina Glacier, Alaska

    NASA Image and Video Library

    2003-05-01

    Malaspina Glacier in southeastern Alaska is considered the classic example of a piedmont glacier. Piedmont glaciers occur where valley glaciers exit a mountain range onto broad lowlands, are no longer laterally confined, and spread to become wide lobes.

  20. Westerly Wind Variability in New Zealand Fjords: Signals of Marine and Terrestrial Sedimentation

    NASA Astrophysics Data System (ADS)

    Knudson, K. P.; Hendy, I. L.; Neil, H.

    2009-12-01

    Fundamental to our understanding of future climate change is how major atmospheric-oceanic interactions have responded to previous climate variability. Here we use sediment cores from New Zealand fjords to reconstruct the position of a major atmospheric system, the Southern Hemisphere Westerly Winds. This wind system teleconnects the tropics to polar regions and is modulated in strength and position by interannual/decadal variability such as the El Niño-Southern Oscillation, Inter-decadal Pacific Oscillation, and Southern Annular Mode. Fluctuation in the positions of the Westerly Winds has a dramatic affect on the amount of precipitation that the fjords receive. When the Westerly Winds migrate northward (e.g. El Niño conditions), New Zealand experiences cyclonic southwesterly air flow over the Southern Alps that causes the West Coast to receive significantly more precipitation. When the Westerly Winds move southward (e.g. La Niña conditions), high pressure over New Zealand results in anticyclonic northeasterly air flow and dry conditions on the West Coast. Changes in precipitation greatly influence fjord estuarine circulation, which consists of a low salinity lens of precipitation derived water moving seaward at the surface over a higher salinity layer of marine replacement water. Estuarine circulation may also be affected by strong winds blowing from the west, pushing the freshwater lens landward. This study examines variability in precipitation and wind through changes in the estuarine circulation recorded within the fjords. One “landward” and one “seaward” core from both Milford (S534 and H287) and George (M714 and M717) Sounds of New Zealand’s South Island were sampled. Bulk sediment δ13C and organic C/N ratios were examined to determine the relative contributions of terrestrial versus marine organic matter. We assumed terrestrial organic matter was mainly transported to the fjords via freshwater runoff and is therefore indicative of the presence

  1. Dynamics of phytoplankton distribution and photosynthetic capacity in a western Norwegian fjord during coastal upwelling: Effects on optical properties

    NASA Astrophysics Data System (ADS)

    Erga, Svein Rune; Ssebiyonga, Nicolausi; Frette, Øyvind; Hamre, Børge; Aure, Jan; Strand, Øivind; Strohmeier, Tore

    2012-01-01

    The present study describes the coupling between optical properties and the dynamics of phytoplankton distribution and photosynthetic capacity in the Lysefjord during an exceptional coastal upwelling. At the mouth of the fjord, transparent Coastal water was "piled up" against the sill, while more turbid Fjord water from the outer fjord system was flowing over the sill, creating the intermediate layer which extended further into the fjord. This was reflected by high spectral attenuation coefficients in the upper 10 m of the fjord. Outside the sill, clear water with low spectral attenuation coefficients were found below sill depth down to at least 30 m, while the attenuation coefficients inside the sill were significantly higher between 10 and 20 m. About 4-7 km outwards from the head of the fjord clearer deep basin water was entering the upper layer due to the upwelling which could be traced up to 7 m, bounded by the 7.5 °C and the 31 salinity isolines. In the outer part of the fjord waters with a high chl a content and photosynthetic capacity were observed below the outflowing surface layer containing "old water" from the inner part of the fjord, which was characterized by low nutrient and chl a concentrations. Maximum quantum efficiencies (0.5) were encountered within this subsurface layer. Quantum efficiencies exceeded 0.3 when nitrate and silicate concentrations increased above 2 mmol m -3. About 50% of the PAR light attenuation (0-30 m) was caused by chl a, and the 1% light depth varied between 27 and 35 m along the transect. Due to the influence of freshwater outlets, non-pigmented particles were more abundant in the inner part of the fjord than in the outer part. Colored dissolved organic matter (CDOM) contributed strongly to absorption within the upper 10 m at wavelengths below 470 nm while scattering was the major attenuation contributor for wavelengths above 600 nm. With respect to possible climate change effects on the growth of phytoplankton in

  2. 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.

  3. Alaska Resource Data File, Point Lay quadrangle, Alaska

    USGS Publications Warehouse

    Grybeck, Donald J.

    2006-01-01

    This report gives descriptions of the mineral occurrences in the Point Lay 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.

  4. Modeling the Impact of Glacial Runoff on Fjord Circulation and Submarine Melt Rate using a New Parameterization for Glacial Plumes

    NASA Astrophysics Data System (ADS)

    Cowton, T. R.; Slater, D. A.; Sole, A. J.; Goldberg, D. N.; Nienow, P. W.

    2014-12-01

    The injection at depth of ice sheet runoff into fjords may be an important control on the frontal melt rate of tidewater glaciers. Runoff influences submarine melt rate directly, by generating buoyant plumes adjacent to the ice front, and indirectly, by influencing the circulation of heterogeneous water masses within the fjord. Understanding these processes has been held back, however, by the computational expense of modeling both the fine scale turbulent processes occurring within the buoyant plumes and the coarser scale circulation throughout the remainder of the fjord. Here, we develop a new parameterization for ice marginal plumes within the Massachusetts Institute of Technology General Circulation Model (MITgcm), allowing three-dimensional simulation of large (500 km2) glacial fjords on annual (or longer) timescales. We find that for an idealised fjord (without shelf-driven circulation), subglacial runoff produces a thin, strong and warm down-fjord current in the upper part of the water column, balanced by a thick and slow up-fjord current at greater depth. Submarine melt rates increase with runoff due to higher melt rates where the plume is in contact with the ice front. We find however that annual submarine melt rate across the ice front is relatively insensitive to variability in annual runoff. Better knowledge of the spatial distribution of runoff, controls on melt rate in those areas not directly in contact with plumes and feedback mechanisms linking submarine melting and iceberg calving are necessary to more fully understand the sensitivity of glacier mass balance to runoff-driven fjord circulation.

  5. Relationships between fjord bathymetries and recent glacier behavior: gaining new insight from IceBridge flights over Greenland

    NASA Astrophysics Data System (ADS)

    Porter, D.; Boghosian, A.; Tinto, K. J.; Cochran, J. R.; Bell, R. E.

    2012-12-01

    The geometry of glacial fjords may play a large role in determining the stability of outlet glaciers. Sloping seafloors will feedback on a moving grounding line and shallow sills and deep continental shelf troughs will allow greater interaction with the surrounding ocean water. To better understand the role of fjord bathymetry in the glacier system, Operation IceBridge (OIB) has flown a suite of radar, lidar, gravity and magnetic instruments along the flow lines of previously inaccessible outlet glaciers and their fjords around the Greenlandic coast. Here, we combine newly collected surface elevation, ice thickness data, and gravity and magnetic anomalies from OIB flights, along with ship-based bathymetric profiles, into a single dataset. The combination of these new data are used in the construction of forward models that provide the framework for performing gravity inversions, finally resulting in many new bathymetric charts of previously unmapped fjords in Greenland. These newly created fjord bathymetries are compared to several important characteristics their outlet glaciers and ocean waters. We investigate the importance of glacier parameters such as surface velocity and area changes, as well as newly available oceanographic data from within the fjord, on recent changes in glacier behavior. Are faster flowing glaciers found in fjords with deep sills and a greater exchange with continental shelf water? Comparisons of these glacier-fjord relationships are also separated by region and by glacier type. Are glaciers in the southeast mostly changing in a similar way even though their bed geometries are quite different? These broad correlations are a starting point in an effort to investigate the role of bed geometry in the relationship between external forcing and the observed recent change of many of Greenland's largest outlet glaciers.

  6. 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

  7. Organic carbon sources across salinity gradients in Chilean Fjords: Reloncaví Fjord ( 41°S) and Southern Patagonian ice fields area ( 48°S)

    NASA Astrophysics Data System (ADS)

    Placencia, Juan; Llanos, Gustavo; Contreras, Sergio

    2017-04-01

    The organic matter preserved in marine sediments contains contributions of allochthonous and autochthonous and variable source inputs. Allochthonous sources are terrestrial erosion (including anthropogenic material) of relatively labile and refractory material, while autochthonous sources including marine phytoplankton. In order to establish the sources of the organic matter (allochthonous/autochthonous) and how organic carbon is distributed along a salinity gradient, on this study we examined of organic Carbon/Nitrogen molar ratios (C:N), isotopic composition (δ13C) and n-alkanes (n-C24 to n-C34) in surface sediments from two continuous systems: river-fjord-ocean in Northern Patagonia (41°S-43°S), and glacier-fjord-ocean in central Patagonia (47°S-50°S). The continental inner fjord areas are characterized with sediment enriched in allochthonous organic carbon and high C:N (8-12) and low δ13C values (-23‰ to -26‰). Towards the Pacific Ocean, low C:N (6-7) and high δ13C values (-20‰ to -22‰) suggest prevalent autochthonous marine sources. Estuarine waters with salinity between 2 psu and 30 psu were associated with high C:N and low δ13C values together with odd over even long-chain n-alkane predominance (n-C31, n-C29 and n-C27) in surface sediments. All geochemical proxies suggest a great contribution of terrigenous input by glacier origin rivers, mainly from terrestrial plants in both areas. Our study provides a framework to guide future researches on environmental and climate change on these systems. This study was supported by the Chilean Navy's Hydrographic and Oceanographic Service, the Chilean National Oceanographic Committee through the Grants CONA C19F1308 and C20F1404, and the Research Office at Universidad Católica de la Ssma. Concepción.

  8. Response of the Alaska Volcano Observatory to Public Inquiry Concerning the 2006 Eruption of Augustine Volcano, Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Adleman, J. N.

    2006-12-01

    The 2006 eruption of Augustine Volcano provided the Alaska Volcano Observatory (AVO) with an opportunity to test its newly renovated Operations Center (Ops) at the Alaska Science Center in Anchorage. Because of the demand for interagency operations and public communication, Ops became the hub of Augustine monitoring activity, twenty-four hours a day, seven days a week, from January 10 through May 19, 2006. During this time, Ops was staffed by 17 USGS AVO staff, and over two dozen Fairbanks-based AVO staff from the Alaska Department of Geological and Geophysical Surveys and the University of Alaska Fairbanks Geophysical Institute and USGS Volcano Hazards Program staff from outside Alaska. This group engaged in communicating with the public, media, and other responding agencies throughout the eruption. Before and during the eruption, reference sheets - ;including daily talking - were created, vetted, and distributed to prepare staff for questions about the volcano. These resources were compiled into a binder stationed at each Ops phone and available through the AVO computer network. In this way, AVO was able to provide a comprehensive, uniform, and timely response to callers and emails at all three of its cooperative organizations statewide. AVO was proactive in scheduling an Information Scientist for interviews on-site with Anchorage television stations and newspapers several times a week. Scientists available, willing, and able to speak clearly about the current activity were crucial to AVO's response. On January 19, 2006, two public meetings were held in Homer, 120 kilometers northeast of Augustine Volcano. AVO, the West Coast Alaska Tsunami Warning Center, and the Kenai Peninsula Borough Office of Emergency Management gave brief presentations explaining their roles in eruption response. Representatives from several local, state, and federal agencies were also available. In addition to communicating with the public by daily media interviews and phone calls to Ops

  9. Presence of rapidly degrading permafrost plateaus in south-central Alaska

    NASA Astrophysics Data System (ADS)

    Jones, Benjamin M.; Baughman, Carson A.; Romanovsky, Vladimir E.; Parsekian, Andrew D.; Babcock, Esther L.; Stephani, Eva; Jones, Miriam C.; Grosse, Guido; Berg, Edward E.

    2016-11-01

    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 in the western Kenai Peninsula lowlands of south-central Alaska, a region with a MAAT of 1.5 ± 1 °C (1981-2010). 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 at some locations was as shallow as 0.53 m. Late winter surveys (augering, 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 60.0 %, with lateral feature degradation accounting for 85.0 % 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

  10. 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

  11. Prehistoric Alaska: The land

    USGS Publications Warehouse

    Wilson, Frederic H.; Weber, Florence R.; Rennick, Penny

    1994-01-01

    Many Alaskans know the dynamic nature of Alaska’s landscape firsthand. The 1964 earthquake, the 1989 eruption of Mount Redoubt volcano, the frequent earthquakes in the Aleutians and the ever-shifting meanders of the Yukon and Kuskokwim rivers remind them of constant changes to the land. These changes are part of the continuing story of the geologic growth and development of Alaska during hundreds of millions of years. By geologic time, Alaska has only recently come into existence and the dynamic processes that formed it continue to affect it. The landscape we see today has been shaped by glacier and stream erosion or their indirect effects, and to a lesser extent by volcanoes. Most prominently, if less obviously, Alaska has been built by slow movements of the Earth’s crust we call tectonic or mountain-building.During 5 billion years of geologic time, the Earth’s crust has repeatedly broken apart into plates. These plates have recombined, and have shifted positions relative to each other, to the Earth’s rotational axis and to the equator. Large parts of the Earth’s crust, including Alaska, have been built and destroyed by tectonic forces. Alaska is a collage of transported and locally formed fragments of crusts As erosion and deposition reshape the land surface, climatic changes, brought on partly by changing ocean and atmospheric circulation patterns, alter the location and extent of tropical, temperate and arctic environments. We need to understand the results of these processes as they acted upon Alaska to understand the formation of Alaska. Rocks can provide hints of previous environments because they contain traces of ocean floor and lost lands, bits and pieces of ancient history.

  12. Satellite Operations in Alaska

    NASA Astrophysics Data System (ADS)

    Kreller, M. A.

    2016-12-01

    Numerous observational challenges exist across Alaska impacting National Weather Service (NWS) forecast operations and providing decision support services (DSS) to critical core partners and customers. These observational challenges range from limited utility of GOES imagery at higher latitudes, scarcity of observing platforms, to limited radar coverage. Although we are fortunate to receive these valuable and limited data sets, there still remain extensive spatial and temporal data gaps across Alaska. Many forecast challenges in Alaska are similar to those in the CONUS with the detection and monitoring of wildfire conditions, severe thunderstorms, river flooding, and coastal flooding, etc. There are additional unique DSS provided in Alaska including sea ice forecasting, ivu (ice shoves onshore), coastal erosion due to permafrost melt, and extreme hazardous winter conditions (temperatures as low as -80F). In addition to the observational and forecast challenges, the sheer size of the area of responsibility in Alaska is a challenge. NWS operations have always heavily relied on satellite imagery to quickly assess the current weather situation and provide forecast guidance. NWS operations have established several partnerships with the satellite community to help with these challenges. In particular the GOES-R and Joint Polar Satellite System (JPSS) OCONUS Satellite Proving Ground (PG) Programs have not only improved Alaska's observational challenges, but continue to identify new capabilities with the next generation geostationary and polar-orbiting satellite products.. For example, River ice and flood detection products derived from the Suomi-NPP VIIRS satellite imagery with the support of the JPSS Proving Ground and Risk Reduction Program. This presentation will provide examples of how new satellite capabilities are being used in NWS Alaska forecast operations to support DSS, with emphasis on JPSS satellite products. Future satellite utilization or operational needs

  13. Local and remote modulation of ocean heat supply and freshwater runoff in the progracial fjord of Jorge Montt, a rapidly retrating glacier in Patagonia.

    NASA Astrophysics Data System (ADS)

    Moffat, C. F.

    2016-12-01

    The overwhelming majority of glaciers that are part of the Patagonian Ice Fields are retreating. Although many of these glaciers terminate in narrow, deep fjords, the role the ocean might play in ice loss has received little attention. Here, we present analyses of hydrographic surveys from 2010-2016, and the first year-long time series of ocean currents, atmospheric forcing, and hydrographic properties collected in a proglacial fjord in Patagonia. The study site is the fjord where Jorge Montt, the fastest-retreating glacier in the Southern Patagonian Ice Field, terminates. The evolution of the heat supply to the glacier is partially controlled by regional dynamics away from the fjord, which results in intrusions of surface shelf waters entering the larger fjord system in early summer and the deep proglacial fjord in the fall. This warm water remains available outside and enters the mouth of the fjord until late spring. The intrusions result in the deep water near the glacier varying from about 8.5 to 11.5 degrees C in seasonal time-scales. The circulation in the fjord is largely decoupled from the intrusion dynamics. Instead, it is largely controlled by local winds characterized by strong down-fjord winds, particularly in the summer, by runoff events from the glacier, and by the constrains of a shallow sill. Both winds and runoff events contribute to enhanced exchange between the proglacial fjord and the larger fjord system. Runoff events are often contemporaneous with down-fjord wind events, which is consistent with a common forcing, and thus the analysis focuses on the relative importance of local winds and runoff as drivers of exchange and heat supply to the glacier in synoptic to seasonal time-scales. Overall, our results indicate the freshwater fluxes from Jorge Montt glacier are dominated by submarine runoff in the summer, with submarine melting frequently becoming a leading-order component during the rest of the year.

  14. On the influence of topographic factors upon the oxygen consumption rate in sill basins of fjords

    NASA Astrophysics Data System (ADS)

    Aure, Jan; Stigebrandt, Anders

    1989-01-01

    The rate of oxygen consumption has been estimated for 29 different sill basins of fjords, all located in a relatively small area of the Norwegian west coast. It is found that CONS, the volume mean rate of oxygen consumption in a sill basin (i.e. below the sill level), is inversely proportional to the mean depth, Hb, of the sill basin. In addition it is demonstrated that CONS decreases with increasing sill depth, Ht, in an approximately linear fashion. Our results are compatible with a regionally horizontally homogeneous and downward decreasing vertical flux of organic carbon. Based on data from the present set of sill basins, an empirical formula has been derived for CONS as a function of Ht and Hb. This may be looked upon as a regionally valid empirical fjord model which may be used to determine whether or not the oxygen consumption in a sill basin is 'normal'.

  15. Importance of mixotrophic nanoplankton in Aysén Fjord (Southern Chile) during austral winter

    NASA Astrophysics Data System (ADS)

    Czypionka, Till; Vargas, Cristian A.; Silva, Nelson; Daneri, Giovanni; González, Humberto E.; Iriarte, José Luis

    2011-03-01

    Mixotrophy, the combination of autotrophic and heterotrophic nutrition in the same organism, is widespread in planktonic algae. Several reports from temperate and high-latitude fjords in Scandinavia suggest the occurrence of a niche in late summer and autumn during post-bloom conditions in which mixotrophic algae can become important grazers in pelagic ecosystems, accessing the nutrients bound in their prey to overcome nutrient limitation. Here, we experimentally determined the trophic modes and bacterivory rates for the nanoplankton community (2-20 μm) in Aysén Fjord located in the Chilean Northern Patagonia during two contrasting seasons: winter and spring. While mixotrophic nanoplankton was virtually absent from the system in spring, in winter at occasions it even constituted the dominant trophic group of the nanoplankton with abundances of >900 cells mL -1. This indicates a second niche for mixotrophs in winter, when mixotrophy allows overcoming light limitation.

  16. 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

  17. 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

  18. The influence of glacial melt water on bio-optical properties in two contrasting Greenlandic fjords

    NASA Astrophysics Data System (ADS)

    Murray, Ciarán; Markager, Stiig; Stedmon, Colin A.; Juul-Pedersen, Thomas; Sejr, Mikael K.; Bruhn, Annette

    2015-09-01

    Scattering alters the path of photons, but ultimately their removal from the water column occurs by absorption by one of four components: water itself, coloured dissolved organic matter (CDOM), phytoplankton pigments or non-algal particulate matter (NAP). We calculated absorption budgets for two fjordal systems, Godthåbsfjord (SW Greenland) and Young Sound (NE Greenland), based on these components and evaluated the fate of solar radiation in each system. Absorption by phytoplankton pigment accounted for 15-32% of photons in Godthåbsfjord whilst in Young Sound the corresponding fraction was only 5-8%. NAP accounted for 13-25% of absorption in Young Sound and only 7-8% in Godthåbsfjord whilst fractions of absorption by CDOM were more similar: 6-13% in Godthåbsfjord and 6-18% in Young Sound. In typical temperate estuarine systems, nutrients, CDOM and particulate matter are supplied by riverine sources. Increased nutrient supply will tend to increase productivity whilst increased concentrations of CDOM and particles will increase light attenuation, thereby reducing productivity. The two Greenlandic fjords differ from typical estuarine systems in that their supply of nutrients and particles is decoupled. Freshwater feeding them comes from glacial melt and contains particles but low concentrations of nutrients. New nutrients are supplied by entrainment of oceanic water at the mouths of the fjords and sediment-water exchange of remineralized nutrients. Attenuation and thereby light availability in the two fjords is strongly correlated with turbidity (Godthåbsfjord: r2 = 0.90 p < 0.01, Young Sound: r2 = 0.82 p < 0.001) and we conclude that loading of particulate matter controls light attenuation, and through this may influence primary production. Previous studies argue that warming due to climate change will increase productivity in the fjords. We suggest that increased runoff and particle load may have an opposite effect.

  19. Sources and turnover of organic carbon and methane in fjord and shelf sediments off northern Norway

    NASA Astrophysics Data System (ADS)

    Sauer, Simone; Hong, Wei-Li; Knies, Jochen; Lepland, Aivo; Forwick, Matthias; Klug, Martin; Eichinger, Florian; Baranwal, Soma; Crémière, Antoine; Chand, Shyam; Schubert, Carsten J.

    2016-10-01

    To better understand the present and past carbon cycling and transformation processes in methane-influenced fjord and shelf areas of northern Norway, we compared two sediment cores from the Hola trough and from Ullsfjorden. We investigated (1) the organic matter composition and sedimentological characteristics to study the sources of organic carbon (Corg) and the factors influencing Corg burial, (2) pore water geochemistry to determine the contribution of organoclastic sulfate reduction and methanogenesis to total organic carbon turnover, and (3) the carbon isotopic signature of hydrocarbons to identify the carbon transformation processes and gas sources. High sedimentation and Corg accumulation rates in Ullsfjorden support the notion that fjords are important Corg sinks. The depth of the sulfate-methane-transition (SMT) in the fjord is controlled by the supply of predominantly marine organic matter to the sediment. Organoclastic sulfate reduction accounts for 60% of the total depth-integrated sulfate reduction in the fjord. In spite of the presence of ethane, propane, and butane, we suggest a purely microbial origin of light hydrocarbons in the sediments based on their low δ13C values. In the Hola trough, sedimentation and Corg accumulation rates changed during the deglacial-to-post-glacial transition from approximately 80 cm ka-1 to erosion at present. Thus, Corg burial in this part of the shelf is presently absent. Low organic matter content in the sediment and low rates of organoclastic sulfate reduction (only 3% of total depth-integrated sulfate reduction) entail that the shallow depth of the SMT is controlled mostly by ascending thermogenic methane from deeper sources.

  20. 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

  1. 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

  2. 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.

  3. The seasonal distribution of freshwater from meteoric sources and sea ice melt in Svalbard fjords

    NASA Astrophysics Data System (ADS)

    Drysdale, L.; Meredith, M. P.; Cottier, F.; Inall, M.; Abrahamsen, E. P.; Jenkins, A.

    2016-02-01

    Accelerated retreat of glaciers in regions of the Arctic, such as Svalbard, causes the release of excess freshwater to coastal estuaries. This freshwater has a stratifying effect on the water column, thus influencing processes such as shelf exchange, heat delivery to the surface, and biological productivity. The freshwater budgets of high latitude fjord systems, however, are poorly understood, with multiple sources (including also sea ice melt and direct precipitation) contributing. The use of stable isotopes of oxygen as a water mass tracer, when measured alongside salinity, is a powerful technique for quantitatively decomposing the freshwater budget. We present a new record of glacial melt and sea-ice melt distributions during late summer and early spring from three different fjords around Svalbard using full depth profiles of oxygen isotopes. We find that glacial meltwater is widespread in the western fjords where there has been a strong influence of Atlantic water, while sea ice melt was the dominant source of freshwater to the north of the archipelago. These results are examined in the context of a simple model of the region, which is used to determine the circulation and stratification response under changing freshwater forcing conditions.

  4. 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.

  5. Salinity and temperature structure of a freezing Arctic fjord-monitored by white whales (Delphinapterus leucas)

    NASA Astrophysics Data System (ADS)

    Lydersen, Christian; Nøst, Ole Anders; Lovell, Phil; McConnell, Bernie J.; Gammelsrød, Tor; Hunter, Colin; Fedak, Michael A.; Kovacs, Kit M.

    2002-12-01

    In this study we report results from satellite-linked conductivity-temperature-depth (CTD) loggers that were deployed on wild, free-ranging white whales to study the oceanographic structure of an Arctic fjord, Storfjorden, Svalbard. The whales dove to the bottom of the fjord routinely during the study and occupied areas with up to 90% ice-cover, where performance of conventional ship-based CTD-casts would have been difficult. During the initial period of freezing in the fjord, over a period of approximately 2 weeks, 540 CTD profiles were successfully transmitted. The data indicate that Storfjorden has a substantial inflow of warm North Atlantic Water; this is contrary to conventional wisdom that has suggested that it contains only cold Arctic water. This study confirms that marine-mammal-based CTDs have enormous potential for cost-effective, future oceanographic studies; many different marine mammal species target oceanographic discontinuities for foraging and thus may be good `adaptive samplers' that naturally seek areas of high oceanographic interest.

  6. A mechanism for onset of diatom blooms in a fjord with persistent salinity stratification

    NASA Astrophysics Data System (ADS)

    Goebel, N. L.; Wing, S. R.; Boyd, P. W.

    2005-08-01

    We demonstrate that episodic high freshwater influx from the Manapouri hydroelectric power station and storms promote diatom blooms (15 mg chlorophyll m -3) during spring, summer and autumn in Doubtful Sound, New Zealand, a fjord with semi-permanent salinity stratification. Diatom blooms form when mixing of the surface low salinity layer (LSL - high in silicic acid and low in nitrate and phosphate) and the underlying saline layer (SL - low in silicic acid but relatively high in nitrate and phosphate) reduce nutrient limitations in the thin photic zone of the fjord. We used time series of salinity, macronutrient concentrations, irradiance, and chlorophyll a (February 1997 to January 1999) from stations along the main axis of the fjord to investigate this proposed mechanism. A multiple regression analysis reveals that increases in wind velocity and silicic acid and decrease in phosphate explained 27% of the variance in phytoplankton stocks, indicating that natural and anthropogenic increases in freshwater and silicic acid input and mixing of the LSL and SL play an important role in supporting a predominant diatom community in this system.

  7. Actinomycetes from sediments in the Trondheim fjord, Norway: diversity and biological activity.

    PubMed

    Bredholt, Harald; Fjaervik, Espen; Johnsen, Geir; Zotchev, Sergey B

    2008-01-23

    The marine environment represents a largely untapped source for isolation of new microorganisms with potential to produce biologically active secondary metabolites. Among such microorganisms, Gram-positive actinomycete bacteria are of special interest, since they are known to produce chemically diverse compounds with a wide range of biological activities. We have set out to isolate and characterize actinomycete bacteria from the sediments in one of the largest Norwegian fjords, the Trondheim fjord, with respect to diversity and antibiotic-producing potential. Approximately 3,200 actinomycete bacteria were isolated using four different agar media from the sediment samples collected at different locations and depths (4.5 to 450 m). Grouping of the isolates first according to the morphology followed by characterization of isolates chosen as group representatives by molecular taxonomy revealed that Micromonospora was the dominating actinomycete genus isolated from the sediments. The deep water sediments contained a higher relative amount of Micromonospora compared to the shallow water samples. Nine percent of the isolates clearly required sea water for normal growth, suggesting that these strains represent obligate marine organisms. Extensive screening of the extracts from all collected isolates for antibacterial and antifungal activities revealed strong antibiotic-producing potential among them. The latter implies that actinomycetes from marine sediments in Norwegian fjords can be potential sources for the discovery of novel anti-infective agents.

  8. Observations and Modelling of the Atmospheric Boundary Layer Over Sea-Ice in a Svalbard Fjord

    NASA Astrophysics Data System (ADS)

    Mäkiranta, Eeva; Vihma, Timo; Sjöblom, Anna; Tastula, Esa-Matti

    2011-07-01

    Sonic anemometer and profile mast measurements made in Wahlenbergfjorden, Svalbard Arctic archipelago, in May 2006 and April 2007 were employed to study the atmospheric boundary layer over sea-ice. The turbulent surface fluxes of momentum and sensible heat were calculated using eddy correlation and gradient methods. The results showed that the literature-based universal functions underestimated turbulent mixing in strongly stable conditions. The validity of the Monin-Obukhov similarity theory was questionable for cross-fjord flow directions and in the presence of mesoscale variability or topographic effects. The aerodynamic roughness length showed a dependence on the wind direction. The mean roughness length for along-fjord wind directions was (2.4 ± 2.6) × 10-4 m, whereas that for cross-fjord directions was (5.4 ± 2.8) × 10-3 m. The thermal stratification and turbulent fluxes were affected by the synoptic situation with large differences between the 2 years. Channelling effects and drainage flows occurred especially during a weak large-scale flow. The study periods were simulated applying the Weather Research and Forecasting (WRF) model with 1-km horizontal resolution in the finest domain. The results for the 2-m air temperature and friction velocity were good, but the model failed to reproduce the spatial variability in wind direction between measurement sites 3 km apart. The model suggested that wind shear above the stable boundary layer provided a non-local source for the turbulence observed.

  9. Multibeam Bathymetry Surveys in Fjords and Coastal Areas of West-Greenland

    NASA Astrophysics Data System (ADS)

    Weinrebe, W.; Kuijpers, A.; Klaucke, I.; Fink, M.

    2009-12-01

    High-resolution bathymetric maps are not available for many of the sparsely populated fjords in West-Greenland as those areas are remote and difficult to navigate. During a recent (2007) cruise of RV Maria S. Merian large coastal areas of West-Greenland including some of these fjords were mapped in detail with multibeam bathymetry, among them many parts which never had been investigated before. The surveys covered the Godthabfjord, Nordre Stroemfjord, Disko Bay, Vaigat, Uumannaq-Fjord and the Marmorilik area. The data acquired by a Kongsberg EM120 deep water multibeam and a Kongsberg EM1002 shallow water multibeam system were of very good quality. In summer 2008 the survey in the Disko Bay area was extended far into the Ilulissat Icefjord using a local boat and a portable Seabeam 1180 multibeam system. The seafloor in these areas is intensively shaped by glacial processes which create characteristic submarine landforms. Revealing the morphology helps to understand these processes, high-resolution bathymetry displays the relief and morphology of the seafloor. In particular, rims and sills which may mark ancient ice margins have been identified in the bathymetry. Multibeam mapping was continued also during transits off the coast in the Davis Strait. Here areas sculptured intensively by iceberg plough marks were found. Several distinct patterns of directions can be identified which probably represent different phases of drift. The water depth here is generally greater than 240 m documenting rather deep going icebergs.

  10. Substantial stores of sedimentary carbon held in mid-latitude fjords

    NASA Astrophysics Data System (ADS)

    Smeaton, Craig; Austin, William E. N.; Davies, Althea L.; Baltzer, Agnès; Abell, Richard E.; Howe, John A.

    2016-10-01

    Quantifying marine sedimentary carbon stocks is key to improving our understanding of long-term storage of carbon in the coastal ocean and to further constraining the global carbon cycle. Here we present a methodological approach which combines seismic geophysics and geochemical measurements to quantitatively estimate the total stock of carbon held within marine sediment. Through the application of this methodology to Loch Sunart, a fjord on the west coast of Scotland, we have generated the first full sedimentary carbon inventory for a fjordic system. The sediments of Loch Sunart hold 26.9 ± 0.5 Mt of carbon split between 11.5 ± 0.2 and 15.0 ± 0.4 Mt of organic and inorganic carbon respectively. These new quantitative estimates of carbon stored in coastal sediments are significantly higher than previous estimates. Through an area-normalised comparison to adjacent Scottish peatland carbon stocks, we have determined that these mid-latitude fjords are significantly more effective as carbon stores than their terrestrial counterparts. This initial work supports the concept that fjords are important environments for the burial and long-term storage of carbon and therefore should be considered and treated as unique environments within the global carbon cycle.

  11. 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.

  12. 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.

  13. 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.

  14. Observing lake ice phenology across Alaska using in situ sensors, aircraft, and satellites

    NASA Astrophysics Data System (ADS)

    Arp, C. D.; Jones, B. M.; Grosse, G.; Bodony, K.; Sturdivant, E.; Frey, K. E.

    2013-12-01

    The timing of ice-out in high latitudes is a fundamental threshold for lake ecosystems and an indicator of climate change. Thus, there is a need to understand lake ice phenology at multiple scales from small to large lakes and across lake-rich landscapes. In this study, we observed ice-out timing for large lakes using MODIS imagery in eleven lake districts across Alaska from 2007 - 2012 and validated these and expanded to smaller lakes using in situ sensors and shore-based cameras. Over this six year period, the mean lake ice-out for all lakes was 27 May and ranged from 07 May in Kenai to 06 July in Arctic Coastal Plain lake districts with relatively low interannual variability. Approximately 80% of the variation in ice out timing was explained by the 0°C air temperature isotherm date (ATID) and lake area. Shoreline irregularity, watershed area, and river connectivity explained additional variation in some districts. Inter-district analysis of coherence showed synchronous ice-out patterns with the exception of the two arctic coastal districts where ice-out occurs later (June - July) and regional climatology is strongly sea-ice influenced. Following this baseline analysis to document spatial and temporal variability, Alaska experienced record cold spring conditions in 2013. This apparent anomaly from long-term trends of earlier springs in northern latitudes provided an opportunity to validate empirical models and look at lake responses under conditions more representative of times before modern warming. In 2013 mean ice-out for all study lakes was 13 days later than mean for the previous six year observation period. The lower latitude and interior lake districts Denali, Kenai, and Minto Flats had ice-free conditions >18 days later in 2013 than the baseline period compared to higher latitude and coastal districts Beringia, Yukon-Kuskokwim Delta, and Arctic Coastal Plain became ice-free well within the range of recent interannual variability. Observations from this

  15. Seasonal plankton variability in Chilean Patagonia fjords: Carbon flow through the pelagic food web of Aysen Fjord and plankton dynamics in the Moraleda Channel basin

    NASA Astrophysics Data System (ADS)

    González, H. E.; Castro, L.; Daneri, G.; Iriarte, J. L.; Silva, N.; Vargas, C. A.; Giesecke, R.; Sánchez, N.

    2011-03-01

    Two research cruises ( CIMAR 13 Fiordos) were conducted in the N-S oriented macrobasin of the Moraleda Channel (42-47°S), which includes the E-W oriented Puyuhuapi Channel and Aysen Fjord, during two contrasting productive seasons: austral winter (27 July-7 August 2007) and spring (2-12 November 2007). These campaigns set out to assess the spatio-temporal variability, defined by the local topography along Moraleda Channel, in the biological, physical, and chemical oceanographic characteristics of different microbasins and to quantify the carbon budget of the pelagic trophic webs of Aysen Fjord. Seasonal carbon fluxes and fjord-system functioning vary widely in our study area. In terms of spatial topography, two constriction sills (Meninea and Elefantes) define three microbasins along Moraleda Channel, herein the (1) north (Guafo-Meninea), (2) central (Meninea-Elefantes), and (3) south (Elefantes-San Rafael Lagoon) microbasins. In winter, nutrient concentrations were high (i.e. nitrate range: 21-14 μM) and primary production was low (153-310 mgC m -2 d -1), suggesting that reduced light radiation depressed the plankton dynamics throughout Moraleda Channel. In spring, primary production followed a conspicuous N-S gradient, which was the highest (5167 mgC m -2 d -1) in the north microbasin and the lowest (742 mgC m -2 d -1) in the south microbasin. The seasonal pattern of the semi-enclosed Puyuhuapi Channel and Aysen Fjord, however, revealed no significant differences in primary production (˜800 mgC m -2 d -1), and vertical fluxes of particulate organic carbon were nearly twice as high in spring as in winter (266 vs. 168 mgC m -2 d -1). At the time-series station (St. 79), the lithogenic fraction dominated the total sedimented matter (seston). The role of euphausiids in the biological carbon pump of the Patagonian fjords was evident, given the predominance of zooplankton fecal material, mostly euphausiid fecal strings (46% of all fecal material), among the

  16. 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.

  17. Reassessment of seismically induced, tsunamigenic submarine slpe failures in Port Valdez, Alaska, USA

    USGS Publications Warehouse

    Lee, H.J.; Ryan, H.F.; Haeussler, P.J.; Kayen, R.E.; Hampton, M.A.; Locat, Jacques; Suleimani, E.; Alexander, C.R.; Lykousis, Vasilios; Sakellariou, Dimitris; Locat, Jacques

    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 tsunami wave 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.

  18. 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.

  19. Sediment thicknesses and holocene glacial marine sedimentation rates in three east Greenland fjords (ca. 68°N)

    USGS Publications Warehouse

    Andrews, J.T.; Milliman, John D.; Jennings, A.E.; Rynes, N.; Dwyer, J.

    1994-01-01

    We compared measured and estimated sediment budgets in heavily glaciated fjords in East Greenland. Mass balance calculations and regional glacio-climatic conditions suggest that the sediment flux to the seafloor in Kangerdlugssuaq and Nansen fjords should be dominated by iceberg rafting and not by the rain-out of suspended particulates in meltwater, as the glacier calving flux is estimated at 15 and $2 km^{3}/yr$, compared to meltwater volumes of 4.4 and $1.7 km^{3}/yr$, respectively. Gravity cores in the three fjords indicate that the uppermost 1-2.5 m of sediment consists of diamictons or fine-grained laminated muds. AMS radiocarbon dates on calcareous foramininfera or shells (16 total) indicate sedimentation rates of 110 to 340 cm/ka within the fjords over the last 1 ka, and 10-20 cm/ka during the Holecene on the inner and middle shelf. Annual sediment discharge is around $0.67 \\times 10^{6}$ tonnes/yr within the Kangerdlugssuaq Fjord and Trough system, which translates into an average basin-wide rate of denudation of 0.01 mm/yr (0.01 m/ka). Air gun and deep-towed (Huntec) seismic profiling was carried out in Kangerdlugssuaq and Nansen fjords, East Greenland, and showed that sediment fills averaged 500 and 350 m respectively; they consist primarily of acoustically stratified sediments. If the sediment fills are entirely Holocene in age then the required average sediment accumulation rates of 35-50 m/ka are an order of magnitude larger than the $^{14}C $controlled rates of the last 1-2 ka. This raises the possibility that fjord sediments may be by-passed and not always recycled during glacial advances; this will affect sedimentation rates on adjacent shelves and deep-sea areas during successive glaciations

  20. Last Glacial - Present Glacial Activity in East Greenland Fjords Inferred from Swath Bathymetry and High-Resolution Seismic Data

    NASA Astrophysics Data System (ADS)

    Forwick, M.; Laberg, J. S.; Husum, K.; Olsen, I. L.

    2014-12-01

    Swath bathymetry and high-resolution penetration echo sounder (chirp) data from fjords and sounds between Kong Oscars Fjord and Bredefjord, East Greenland, reveal glacial landforms and sedimentary processes that can be used to infer glacial activity from the last glacial to the present. Relatively straight, linear features oriented parallel to the fjord axes, as well as beyond the mouths of some fjords, are interpreted to be glacial lineations providing evidence of fast-flowing grounded ice draining the eastern parts of the Greenland Ice Sheet during the last glacial. In some areas, the glacial lineations are the only preserved glacigenic landfjorms (e.g. beyond the mouth of Bredefjord). However, in other areas, they are covered with multiple transverse ridges interpreted to be small terminal moraines (e.g. in Youngsund). Whereas the absence of such moraines is suggested to represent a rapid ice retreat due to lift-up and disintegration during parts of the deglaciation, their presence reflects that multiple halts and/or re-advances interrupted the retreat. Acoustically stratified sediment sequences dominate the fjord-fill stratigraphies (up to 180 ms two-way travel time). These deposits are suggested to reflect repeatedly changing lithological compositions in a glacimarine environment where deposition mainly occurred from suspension fall-out, in addition to ice rafting from icebergs calving off from tidewater glaciers, and sea ice. The stratified deposits form often relatively uniform drapes indicating that the tidewater glaciers were mainly located near the fjord heads since the last deglaciation. However, acoustically transparent bodies with irregular geometries, intercalated within the stratified deposits, occur in some of the inner fjords. These are suggested to be glacigenic sediment wedges (debris-flow lobes) that formed during relatively recent advances of tidewater glaciers (e.g. in Nordfjord and Moskusoksefjord).

  1. 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

  2. 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

  3. 2012 Alaska Performance Scholarship Outcomes Report

    ERIC Educational Resources Information Center

    Rae, Brian

    2012-01-01

    As set forth in Alaska Statute 14.43.840, Alaska's 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 first annual report on the Alaska Performance Scholarship to the public, the Governor, and the…

  4. 75 FR 28816 - Alaska Native Claims Selection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-24

    ... Bureau of Land Management Alaska Native Claims Selection AGENCY: Bureau of Land Management, Interior... the Alaska Native Claims Settlement Act. The lands are located north of Fort Yukon, Alaska...: Bureau of Land Management, Alaska State Office, 222 West Seventh Avenue, 13, Anchorage, Alaska 99513-7504...

  5. 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.

  6. 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.

  7. 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

  8. Fluctuations in export productivity over the last century from sediments of a southern Chilean fjord (44°S)

    NASA Astrophysics Data System (ADS)

    Sepúlveda, Julio; Pantoja, Silvio; Hughen, Konrad; Lange, Carina; Gonzalez, Fidelina; Muñoz, Práxedes; Rebolledo, Lorena; Castro, Rodrigo; Contreras, Sergio; Ávila, Alejandro; Rossel, Pamela; Lorca, Gisella; Salamanca, Marco; Silva, Nelson

    2005-11-01

    Here we present the first reconstruction of changes in surface primary production during the last century from the Puyuhuapi fjord in southern Chile, using a variety of parameters (diatoms, biogenic silica, total organic carbon, chlorins, and proteins) as productivity proxies. Two sediment cores from the head and the center of the fjord were analyzed and compared to gain insights on past changes in productivity in these two different depositional environments. Higher sedimentation rates found at the head of the fjord result from the combination of a shallower water column and a restricted circulation by the occurrence of a sill. Additionally, sediment mixing depths estimated from 210Pb data suggest that suboxic conditions may dominate the bottom water and the sediment-water interface in this location. Productivity of the Puyuhuapi fjord during the last century was characterized by a constant increase from the late 19th century to the early 1980s, then decreased until the late 1990s, and then rose again to present-day values. The influence of rainfall on productivity was most noticeable during periods of low rainfall, which coincided with decreased overall productivity within the Puyuhuapi fjord. Simultaneous variations in productivity and rainfall in the study area suggest that marine productivity could respond to atmospheric-oceanic interactions at a local scale. At a regional scale, marine productivity of the area may be related to other large-scale processes such as the El Niño Southern Oscillation.

  9. Integrating satellite observations and modern climate measurements with the recent sedimentary record: An example from Southeast Alaska

    NASA Astrophysics Data System (ADS)

    Addison, Jason A.; Finney, Bruce P.; Jaeger, John M.; Stoner, Joseph S.; Norris, Richard D.; Hangsterfer, Alexandra

    2013-07-01

    Assessments of climate change over time scales that exceed the last 100 years require robust integration of high-quality instrument records with high-resolution paleoclimate proxy data. In this study, we show that the recent biogenic sediments accumulating in two temperate ice-free fjords in Southeast Alaska preserve evidence of North Pacific Ocean climate variability as recorded by both instrument networks and satellite observations. Multicore samples EW0408-32MC and EW0408-43MC were investigated with 137Cs and excess 210Pb geochronometry, three-dimensional computed tomography, high-resolution scanning XRF geochemistry, and organic stable isotope analyses. EW0408-32MC (57.162°N, 135.357°W, 146 m depth) is a moderately bioturbated continuous record that spans AD ˜1930-2004. EW0408-43MC (56.965°N, 135.268°W, 91 m depth) is composed of laminated diatom oozes, a turbidite, and a hypopycnal plume (river flood) deposit. A discontinuous event-based varve chronology indicates 43MC spans AD ˜1940-1981. Decadal-scale fluctuations in sedimentary Br/Cl ratios accurately reflect changes in marine organic matter accumulation that display the same temporal pattern as that of the Pacific Decadal Oscillation. An estimated Sitka summer productivity parameter calibrated using SeaWiFS satellite observations support these relationships. The correlation of North Pacific climate regime states, primary productivity, and sediment geochemistry indicate the accumulation of biogenic sediment in Southeast Alaska temperate fjords can be used as a sensitive recorder of past productivity variability, and by inference, past climate conditions in the high-latitude Gulf of Alaska.

  10. Alaska's forest resource.

    Treesearch

    O. Keith. Hutchison

    1968-01-01

    Alaska's romantic past includes the magnetic lure of gold; the mad stampede to strike it rich; success and heartbreak; men and animals battling snow, ice, spring breakup, insects, and loneliness; dog teams at work and on desperate missions; river steamers battling the Yukon; bush pilots performing miraculous flights; and hordes of salmon taken by traps and seine...

  11. Beating Alaska's Bush.

    ERIC Educational Resources Information Center

    Meade, Kirk

    1981-01-01

    Relates some of the challenges involved in teaching English to Yup'ik Eskimos in the rural areas around Bethel, Alaska. Focuses on problems of student attrition, uninformed attitudes of white instructors, and the operations and failings of the delivery system, which employs itinerant field concept coordinators and campus-based instructors. (AYC)

  12. 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.

  13. 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)

  14. The Alaska experience

    NASA Technical Reports Server (NTRS)

    Mutter, D. L.

    1981-01-01

    The management responsibilities of the Alaska Department of Natural Resources are summarized and the establishment of a geoprocessor system is described. Specific capabilities were defined based on surveys of potential users and pre-existing systems. The procurement process, the initially purchased equipment, and system upgrading are described. Cost, installation and maintenance, site location, training, and staffing of the system are examined.

  15. The Alaska vegetation classification.

    Treesearch

    L.A. Viereck; C.T. Dyrness; A.R. Batten; K.J. Wenzlick

    1992-01-01

    The Alaska vegetation classification presented here is a comprehensive, statewide system that has been under development since 1976. The classification is based, as much as possible, on the characteristics of the vegetation itself and is designed to categorize existing vegetation, not potential vegetation. A hierarchical system with five levels of resolution is used...

  16. 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.

  17. 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 comments.…

  18. 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…

  19. 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.

  20. Alaska's Logging Camp School.

    ERIC Educational Resources Information Center

    Millward, Robert E.

    1999-01-01

    A visit to Ketchikan, Alaska, reveals a floating, one-teacher logging-camp school that uses multiage grouping and interdisciplinary teaching. There are 10 students. The school gym and playground, bunkhouse, fuel tanks, mess hall, and students' homes bob up and down and are often moved to other sites. (MLH)

  1. 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…

  2. Phytomass in southwest Alaska.

    Treesearch

    Bert R. Mead

    2000-01-01

    Phytomass tables are presented for southwest Alaska. The methods used to estimate plant weight and occurrence in the river basin are described and discussed. Average weight is shown for each sampled species of tree, shrub, grass, forb, lichen, and moss in 19 forest and 48 nonforest vegetation types. Species frequency of occurrence and species constancy within the type...

  3. EPA Research in Alaska

    EPA Pesticide Factsheets

    EPA’s collaboration with the DEC and the Air Force on PFAS sampling and analytical methods is key to ensuring valid, defensible data are collected on these emerging contaminants that are being found in soil, groundwater and drinking water in Alaska.

  4. 50 CFR 32.21 - Alaska.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... WILDLIFE REFUGE SYSTEM HUNTING AND FISHING Refuge-Specific Regulations for Hunting and Fishing § 32.21 Alaska. Alaska refuges are opened to hunting, fishing and trapping pursuant to the Alaska National...

  5. 50 CFR 32.21 - Alaska.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... WILDLIFE REFUGE SYSTEM HUNTING AND FISHING Refuge-Specific Regulations for Hunting and Fishing § 32.21 Alaska. Alaska refuges are opened to hunting, fishing and trapping pursuant to the Alaska National...

  6. 50 CFR 32.21 - Alaska.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... WILDLIFE REFUGE SYSTEM HUNTING AND FISHING Refuge-Specific Regulations for Hunting and Fishing § 32.21 Alaska. Alaska refuges are opened to hunting, fishing and trapping pursuant to the Alaska National...

  7. 50 CFR 32.21 - Alaska.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... WILDLIFE REFUGE SYSTEM HUNTING AND FISHING Refuge-Specific Regulations for Hunting and Fishing § 32.21 Alaska. Alaska refuges are opened to hunting, fishing and trapping pursuant to the Alaska National...

  8. 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.

  9. A reassessment of the role of ice sheet glaciation in the long-term evolution of the East Greenland fjord region

    NASA Astrophysics Data System (ADS)

    Swift, Darrel A.; Persano, Cristina; Stuart, Finlay M.; Gallagher, Kerry; Whitham, Andrew

    2008-05-01

    The long-term evolution of the East Greenland fjord region is investigated using geomorphological and stratigraphical evidence to: (1) assess the nature of landscape modification caused by late Cenozoic ice sheet glaciation; and (2) relate patterns of glacial landscape modification to first-order (i.e. continent-margin scale) topography and geology. Geomorphological and stratigraphical evidence demonstrates evolution of the first-order topography and incision of at least part of the present first-order fjord system by ˜ 55 Ma. This hypothesis is tested using apatite (U-Th)/He ages for samples from two bedrock profiles near Kong Oscar Fjord. The thermochronology supports landscape evolution before 55 Ma, followed by relative tectonic stability, because it indicates rapid denudation around the time of rifting that occurred prior to continental breakup (i.e. between ˜ 75 and 55 Ma). The nature of landscape modification caused by late Cenozoic glacial erosion appears to have been controlled by first-order topography and geology, with selective ice sheet erosion in areas of high-elevation Caledonian basement and apparently little glacial erosion of low-elevation Mesozoic sedimentary strata. Nevertheless, fjord morphometry demonstrates systematic evolution of the first-order fjord system from confined and overdeepened fjords in Caledonian basement to wider and disproportionately larger fjords in Mesozoic strata. The latter indicates that changes in lithological strength enabled the development of more efficient fjord morphology under full glacial conditions that may have promoted fast ice flow.

  10. 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.

  11. Postglacial vegetation history of the Kachemak Bay area, Cook Inlet, south-central Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

    USGS Publications Warehouse

    Ager, Thomas A.

    2000-01-01

    Pollen records from two sites on the north shore of Kachemak Bay, south-central Alaska, provide the first radiocarbon-dated histories of postglacial vegetation development for southern Cook Inlet. During the late Wisconsin glacial interval, glaciers covered most of Cook Inlet. Deglaciation of Kachemak Bay began prior to 13,000 yr B.P. Pollen evidence indicates that a pioneering herbaceous tundra began to develop by 12,800 yr B.P., but was soon replaced by a shrub tundra of dwarf birch (Betula), Ericales (Ericaceae and Empetrum) and willows (Salix).By 9,500 yr B.P., a shrub-dominated vegetation of alders (Alnus) and willows, with some deciduous trees (Populus spp.) quickly developed and persisted until late Holocene time. By about 4,000–3,800 yr B.P., spruce trees (Picea glauca and (or) P. mariana) from the interior boreal forests reached the northern Kachemak Bay area from upper Cook Inlet and began to displace the alder-dominated vegetation. A coastal forest of Sitka spruce (Picea sitchensis) began to colonize Kachemak Bay more recently, about 1,650 yr B.P. (minimum age), apparently from sources in Prince William Sound to the east. Where Sitka spruce came into proximity with boreal white spruce (Picea glauca), hybridization occurred, ultimately influencing the spruce forests over a large area of the Kenai Lowland. Some key findings of this study are: (1) the Kachemak Bay-area pollen records do not display persuasive evidence for a “Younger Dryas” cold, dry interval ca. 11,000–10,000 yr B.P. that has been reported from pollen records on Kodiak Island (Gulf of Alaska) and Pleasant Island (southeastern Alaska); (2) at least one species of alder may have survived in refugia in south-central Alaska during the last glacial interval; (3) coastal forests appear to be still migrating west along the coast of south-central Alaska, but their spread northward is being limited by drier, colder winter climates; (4) the mountainous topography of south-central Alaska

  12. 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

    ... 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 the Lower Russian Lake Recreation Area. The withdrawal extended by this order will expire on October 1, 2031...

  13. 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

  14. 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.

  15. Facies characteristics, morphology and depositional models of clay-slide deposits in terraced fjord valleys, Norway

    NASA Astrophysics Data System (ADS)

    Hansen, Louise; Eilertsen, Raymond S.; Solberg, Inger-Lise; Sveian, Harald; Rokoengen, Kåre

    2007-12-01

    Many bedrock-confined fjord valleys along the Norwegian coast contain thick accumulations of fine-grained sediments that were deposited during and after the last deglaciation. The deposits gradually emerged above sea level due to glacioisostatic uplift, and fjord marine sedimentation was gradually followed by shallow marine and fluvial processes. During emergence terraces and river-cut slopes were formed in the valleys. Subsequent leaching of salt ions from the pore water in the marine deposits by groundwater has led to the development of quick clay. The deposits are subject to river erosion and destructive landslides involving quick clay. Most slides are of prehistoric age. Others are known from modern observations as well as from historic records. Landforms such as distinct slide scars or the hummocky terrain of slide deposits may be strongly modified by secondary processes. In addition, deposits from the most liquid part of quick clay slides may have planar surfaces. Clay-slide deposits on a fluvial or deltaic terrace, therefore, are not always easily recognized from morphology, and only exposures may reveal their internal structures and allow them to be distinguished from overbank flood sediments. Detailed sedimentological work shows that slide deposits in such setting consist of distinct facies containing reworked marine sediments. We propose three facies successions of clay-slide deposits that form a continuum. The dominant components of these succession types are: slightly deformed blocks of laminated clay and silt (A), highly deformed clay and silt with gravel clasts (B) and massive to stratified clay and silt with scattered clasts (C). We suggest that in many cases a basal muddy diamicton is a characteristic, and possibly diagnostic feature. Processes and depositional models are interpreted from the different succession types. The results may be relevant for identifying clay-slide deposits elsewhere and may be useful during general mapping of fjord marine

  16. Spectral attenuation of solar radiation in Patagonian fjord and coastal waters and implications for algal photobiology

    NASA Astrophysics Data System (ADS)

    Huovinen, Pirjo; Gómez, Iván

    2011-03-01

    The spectral attenuation of solar irradiation was measured during summer in two types of coastal waters in southern Chile, a north Patagonian fjord (Seno Reloncaví) and open coast (Valdivia). In order to relate the light availability with the light requirements of upper subtidal seaweeds, the saturating irradiance for photosynthesis ( Ek) from P- I curves was measured. In addition the UV risk was assessed. Based on the z1% of PAR, the lower limit of the euphotic zone in the studied systems averaged 21 m ( Kd 0.24 m -1) in Seno Reloncaví and 18 m ( Kd 0.27 m -1) in the coast of Valdivia. Photosynthesis of the studied seaweeds was saturated at markedly lower irradiances than found in their natural depths at the time of the study. Solar radiation penetrating into these depths at both locations largely supports the light requirements for the photosynthesis of subtidal species: 50-160 μmol m -2 s -1 for seaweeds from Seno Reloncaví (7 m tidal range) and 20-115 μmol m -2 s -1 for Valdivia assemblages (2 m tidal range). Optimal light conditions to saturate photosynthesis ( Ek) were present at 10-16 m water depth. The attenuation of solar irradiation did not vary significantly between the fjord and coastal sites of this study. However, the underwater light climates to which seaweeds are exposed in these sites vary significantly because of the stronger influence of tidal range affecting the fjord system as compared with the open coastal site. The patterns of UV-B penetration in these water bodies suggest that seaweeds living in upper littoral zones such as the intertidal and shallow subtidal (<3 m) may be at risk.

  17. 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

  18. Iron Speciation in the Trondheim Fjord from the Perspective of Iron Limitation for Phytoplankton

    NASA Astrophysics Data System (ADS)

    Öztürk, M.; Steinnes, E.; Sakshaug, E.

    2002-08-01

    Concentrations of different Fe species in the Trondheim fjord waters were determined in different seasons by serial columns. Colloidal Fe (ColFe), Anionic organic-Fe complexes (AnOFe), Hydrophobix-lyphophlic organic-Fe complexes (HphOFe) and Chelex labile iron (ClxLFe) were determined before, during and after large river discharges and phytoplankton blooms. Time series of Fe species were obtained at a single location accompanied by data for humic substances, major nutrients, and phytoplankton biomass. Marked seasonal changes in the concentration of iron in various species were evident, and were directly associated with river discharge, especially in the surface waters, but also due to phytoplankton blooms. ColFe dominated in surface waters when the river discharge was high, but decreased with increasing depth. ClxLFe concentrations were lower than that of ColFe formed during the blooms and high river discharge periods. A clear association between the concentration of ClxLFe and phytoplankton blooms implies that ClxLFe may constitute most of the easily available Fe forms. AnOFe was high only during periods of high river discharge. HphOFe increased with phytoplankton bloom. The close correspondence between the distribution of colloidal Fe and dissolved humic substances with fluorophores (fHS), and between Fe (II), particulate Fe (PFe), and fHS in surface waters, made apparent the role of HS on iron speciation, the formation of colloidal Fe and Fe removal. Iron removal seems to be more effective than the riverine inputs and replenishment of Fe to control the dissolved Fe distribution in the fjord. Therefore, phytoplankton growth rate can be sporadically limited by iron in the Trondheim fjord and adjacent coastal waters especially if there will be enhancement of major nutrients.

  19. Holocene Mass Transport Deposits in Western Norwegian fjords and lakes revealing prehistoric earthquake history of Scandinavia

    NASA Astrophysics Data System (ADS)

    Bellwald, B.; Hjelstuen, B. O.; Sejrup, H. P.; Kuvås, J.; Stokowy, T.

    2016-12-01

    The sensitivity of fjord sediments to seismic shaking makes fjord systems appropriate study sites when extending regional earthquake catalogs back in time and when estimating recurrence rates of prehistoric earthquakes in intraplate settings. In this study we compiled evidence of 140 postglacial mass movement events and their associated mass transport deposits (MTDs) from previously analyzed and new sediment cores and high-resolution seismic profiles from 22 fjord systems and six lakes in Western Norway. Evaluation of trigger mechanisms make us infer that most of these mass movement events were initiated by regional earthquakes, and that both climate-related processes and tsunamis most likely can be excluded as trigger mechanism for most of the events. A total of 33 individual earthquakes has been identified, which most likely outbalance the historically recorded events in magnitude, thus indicating magnitudes >6. Frequency plots of MTDs suggest high seismic activity in the early Holocene (11000-9700 cal. yrs BP), followed by seismic quiescence in the mid-Holocene before a seismic reactivation took place at 4000 cal. yrs BP. Coevally-triggered MTDs at 8100 cal. yrs BP are identified in all the archives, and are correlating with the age of the offshore Storegga slide. We estimate earthquake recurrence rates of 1/80 years directly after the last deglaciation of Western Norway (12800-11600 ca. yrs BP), 1/200 years for the early Holocene and 1/300 years for the last 4000 years. Our compilation suggests that the mid-Holocene is characterized by low seismic activity, suggesting recurrence rates of 1/1300 years. Comparisons of the Western Norwegian dataset with paleoseimologic studies of other previously glaciated intraplate settings indicate that both Scandinavia and the Alps show similar trends as Western Norway, whereas Eastern Canada is not correlating with the paleoseismologic trend of this study, which could be explained by different deglaciation histories.

  20. 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.

  1. Fjord sediment record of Holocene climate change in the Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Anderson, John; Minzoni, Rebecca; Wellner, Julia; Majewski, Wojciech

    2014-05-01

    High-resolution paleoclimate records were generated from long sediment cores collected in five fjords of drastically different settings in the Antarctic Peninsula (AP), including Maxwell Bay, Firth of Tay, Herbert Sound, Lapeyrère Bay, and Neny Fjord. These results are augmented by published records from open marine settings of the Palmer Deep and Bransfield Basin and from terrestrial studies to obtain sufficient spatial sampling for regional analysis of Holocene climate events and local forcing mechanisms. These records include SHALDRIL cores acquired through some of the thicker (up to 108 meters) Holocene sections in fjords of the northern AP region. Robust radiocarbon chronology has been established for each site, and several paleoclimate proxies have been applied to identify and characterize climate events. These include magnetic susceptibility, sedimentation rates, grain size, pebble content, TOC, stable isotopes, biogenic silica content, and foraminifera and diatom assemblages. Current data analysis, including application of additional proxies and analysis of additional cores, refines our understanding of the nature and timing of climatic events expressed in each site. Five previously recognized climate intervals are recorded throughout the AP: an early Holocene deglacial interval, the Mid-Holocene Climate Optimum, a minor cooling event in the mid-Holocene followed by a minor warming event, and the late Holocene Neoglacial. The magnitude and timing of these events varies widely--up to a few thousand years--across the AP region and reflects differences in factors such as orographic effects, drainage basin size and altitude, wind patterns, oceanography, and sea-ice coverage. These results suggest that the rapid regional warming and widespread glacial retreat observed during the last century is unprecedented in breadth and synchronicity.

  2. 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

  3. Restricted evaluation of Trichodectes canis (Phthiraptera: Trichodectidae) detection methods in Alaska gray wolves.

    PubMed

    Woldstad, Theresa M; Dullen, Kimberly N; Hundertmark, Kris J; Beckmen, Kimberlee B

    2014-12-01

    Trichodectes canis (Phthiraptera: Trichodectidae) was first documented on Alaska (USA) gray wolves (Canis lupus) on the Kenai Peninsula in 1981. In subsequent years, numerous wolves exhibited visually apparent, moderate to severe infestations. Currently, the Alaska Department of Fish and Game utilizes visual inspection, histopathology, and potassium hydroxide (KOH) hide digestion for T. canis detection. Our objective was to determine optimal sampling locations for T. canis detection. Wolf hides were subjected to lice enumeration using KOH hide digestion. Thirty nine of the 120 wolves examined had lice. Of these 39, total louse burdens ranged from 14 to an extrapolated 80,000. The hides of 12 infested animals were divided into 10 cm by 10 cm subsections and the lice enumerated on a subsection from each of four regions: neck; shoulder; groin; and rump. Combining the data from these 12 wolves, the highest mean proportions of the total louse burdens on individual wolves were found on the rump and differed significantly from the lowest mean proportion on the neck. However, examination of the four subsections failed to detect all infested wolves. Hides from 16 of the 39 infested animals were cut into left and right sides, and each side then cut into four, approximately equal sections: neck and shoulder; chest; abdomen; and rump. Half hides were totally digested from 11 wolves, and whole hides from 5. For these 21 half hides, the highest mean proportions of total louse burdens were found on the rump, and this section had the highest sensitivity for louse detection, regardless of burden. However, removal of this large section from a hide would likely be opposed by hunters and trappers.

  4. 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

  5. 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.

  6. Restricted evaluation of Trichodectes canis (Phthiraptera: Trichodectidae) detection methods in Alaska gray wolves

    PubMed Central

    Woldstad, Theresa M.; Dullen, Kimberly N.; Hundertmark, Kris J.; Beckmen, Kimberlee B.

    2014-01-01

    Trichodectes canis (Phthiraptera: Trichodectidae) was first documented on Alaska (USA) gray wolves (Canis lupus) on the Kenai Peninsula in 1981. In subsequent years, numerous wolves exhibited visually apparent, moderate to severe infestations. Currently, the Alaska Department of Fish and Game utilizes visual inspection, histopathology, and potassium hydroxide (KOH) hide digestion for T. canis detection. Our objective was to determine optimal sampling locations for T. canis detection. Wolf hides were subjected to lice enumeration using KOH hide digestion. Thirty nine of the 120 wolves examined had lice. Of these 39, total louse burdens ranged from 14 to an extrapolated 80,000. The hides of 12 infested animals were divided into 10 cm by 10 cm subsections and the lice enumerated on a subsection from each of four regions: neck; shoulder; groin; and rump. Combining the data from these 12 wolves, the highest mean proportions of the total louse burdens on individual wolves were found on the rump and differed significantly from the lowest mean proportion on the neck. However, examination of the four subsections failed to detect all infested wolves. Hides from 16 of the 39 infested animals were cut into left and right sides, and each side then cut into four, approximately equal sections: neck and shoulder; chest; abdomen; and rump. Half hides were totally digested from 11 wolves, and whole hides from 5. For these 21 half hides, the highest mean proportions of total louse burdens were found on the rump, and this section had the highest sensitivity for louse detection, regardless of burden. However, removal of this large section from a hide would likely be opposed by hunters and trappers. PMID:25426419

  7. Shrinking ponds in subarctic Alaska based on 1950-2002 remotely sensed images

    USGS Publications Warehouse

    Riordan, B.; Verbyla, D.; McGuire, A.D.

    2006-01-01

    Over the past 50 years, Alaska has experienced a warming climate with longer growing seasons, increased potential evapotranspiration, and permafrost warming. Research from the Seward Peninsula and Kenai Peninsula has demonstrated a substantial landscape-level trend in the reduction of surface water and number of closed-basin ponds. We investigated whether this drying trend occurred at nine other regions throughout Alaska. One study region was from the Arctic Coastal Plain where depp permafrost occurs continuously across the landscape. The other eight study regions were from the boreal forest regions where discontinuous permafrost occurs. Mean annual precipitation across the study regions ranged from 100 to over 700 min yr-1. We used remotely sensed imagery from the 1950s to 2002 to inventory over 10,000 closed-basin ponds from at least three periods from this time span. We found a reduction in the area and number of shallow, closed-basin ponds for all boreal regions. In contrast, the Arctic Coastal Plain region had negligible change in the area of closed-basin ponds. Since the 1950s, surface water area of closed-basin ponds included in this analysis decreased by 31 to 4 percent, and the total number of closed-basin ponds surveyed within each study region decreased from 54 to 5 percent. There was a significant increasing trend in annual mean temperature and potential evapotranspiration since the 1950s for all study regions. There was no significant trend in annual precipitation during the same period. The regional trend of shrinking ponds may be due to increased drainage as permafrost warms, or increased evapotranspiration during a warmer and extended growing season. Copyright 2006 by the American Geophysical Union.

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. Kodiak Island, Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Running vertically between Alaska on the right and Russia on the left, the Bering Strait is mostly free of ice in this true-color MODIS image acquired from data captured on May 31, 2001. To the lower right of the image, a phytoplankton bloom appears to be occurring at the mouth of Norton Sound, and is coloring the darker water a bright bluish green. At the bottom center of the image is snow-covered St. Lawrence Island.

  19. 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.

  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.