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Sample records for kenai fjords alaska

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

    USGS Publications Warehouse

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

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

  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. High Natality Rates of Endangered Steller Sea Lions in Kenai Fjords, Alaska and Perceptions of Population Status in the Gulf of Alaska

    PubMed Central

    Maniscalco, John M.; Springer, Alan M.; Parker, Pamela

    2010-01-01

    Steller sea lions experienced a dramatic population collapse of more than 80% in the late 1970s through the 1990s across their western range in Alaska. One of several competing hypotheses about the cause holds that reduced female reproductive rates (natality) substantively contributed to the decline and continue to limit recovery in the Gulf of Alaska despite the fact that there have been very few attempts to directly measure natality in this species. We conducted a longitudinal study of natality among individual Steller sea lions (n = 151) at a rookery and nearby haulouts in Kenai Fjords, Gulf of Alaska during 2003–2009. Multi-state models were built and tested in Program MARK to estimate survival, resighting, and state transition probabilities dependent on whether or not a female gave birth in the previous year. The models that most closely fit the data suggested that females which gave birth had a higher probability of surviving and giving birth in the following year compared to females that did not give birth, indicating some females are more fit than others. Natality, estimated at 69%, was similar to natality for Steller sea lions in the Gulf of Alaska prior to their decline (67%) and much greater than the published estimate for the 2000s (43%) which was hypothesized from an inferential population dynamic model. Reasons for the disparity are discussed, and could be resolved by additional longitudinal estimates of natality at this and other rookeries over changing ocean climate regimes. Such estimates would provide an appropriate assessment of a key parameter of population dynamics in this endangered species which has heretofore been lacking. Without support for depressed natality as the explanation for a lack of recovery of Steller sea lions in the Gulf of Alaska, alternative hypotheses must be more seriously considered. PMID:20386691

  6. High natality rates of endangered Steller sea lions in Kenai Fjords, Alaska and perceptions of population status in the Gulf of Alaska.

    PubMed

    Maniscalco, John M; Springer, Alan M; Parker, Pamela

    2010-01-01

    Steller sea lions experienced a dramatic population collapse of more than 80% in the late 1970s through the 1990s across their western range in Alaska. One of several competing hypotheses about the cause holds that reduced female reproductive rates (natality) substantively contributed to the decline and continue to limit recovery in the Gulf of Alaska despite the fact that there have been very few attempts to directly measure natality in this species. We conducted a longitudinal study of natality among individual Steller sea lions (n = 151) at a rookery and nearby haulouts in Kenai Fjords, Gulf of Alaska during 2003-2009. Multi-state models were built and tested in Program MARK to estimate survival, resighting, and state transition probabilities dependent on whether or not a female gave birth in the previous year. The models that most closely fit the data suggested that females which gave birth had a higher probability of surviving and giving birth in the following year compared to females that did not give birth, indicating some females are more fit than others. Natality, estimated at 69%, was similar to natality for Steller sea lions in the Gulf of Alaska prior to their decline (67%) and much greater than the published estimate for the 2000s (43%) which was hypothesized from an inferential population dynamic model. Reasons for the disparity are discussed, and could be resolved by additional longitudinal estimates of natality at this and other rookeries over changing ocean climate regimes. Such estimates would provide an appropriate assessment of a key parameter of population dynamics in this endangered species which has heretofore been lacking. Without support for depressed natality as the explanation for a lack of recovery of Steller sea lions in the Gulf of Alaska, alternative hypotheses must be more seriously considered. PMID:20386691

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  11. 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...

  12. Accelerating thinning of Kenai Peninsula glaciers, Alaska

    NASA Astrophysics Data System (ADS)

    VanLooy, J.; Forster, R.; Ford, A.

    2006-11-01

    Temperate mountain glaciers are thinning at high rates and significantly contributing to sea level rise. Due to these glaciers' remote locations, remote sensing and digital elevation models (DEMs) are an effective way to calculate their thinning rates and contribution to sea level rise. Comparisons of 1950s United States Geological Survey (USGS) and 2000 Shuttle Radar Topographic Mission (SRTM) DEMs with DEMs produced from Lidar profiles of glacier center-lines indicate thinning rates from the mid-1990s to 1999 (-0.72 +/- 0.13 m y-1) accelerated by a factor of 1.5 as compared with 1950 to mid-1990s (-0.47 +/- 0.01 m y-1) for glaciers on the Harding Icefield. Overall, comparison of USGS and SRTM DEMs indicate the Harding Icefield and Grewingk-Yalik Glacier Complex, Alaska, are thinning -0.61 +/- 0.12 m y-1 from 1950 to 1999.

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  14. 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...

  15. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  16. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  17. 36 CFR 228.80 - Operations within Misty Fjords and Admiralty Island National Monuments, Alaska.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Vegetation Dynamics in the Kenai Lowlands, Alaska during the Late Pleistocene and Holocene

    NASA Astrophysics Data System (ADS)

    Jones, M. C.; Peteet, D. M.

    2005-12-01

    The use of paleoinformation through ecosystem reconstruction can help us understand the behavior and sensitivity of the boreal forest as climate continues to change. A 2.5-meter sediment core extracted from Swanson Fen, a muskeg in the northern Kenai Lowlands on the Kenai Peninsula, Alaska, provides a sensitive Holocene paleoenvironmental record that lies in an ecotone between interior boreal forest and maritime coastal forest today. The core was sampled at 2-cm intervals and processed for pollen and spores. Five intervals were dated using AMS radiocarbon dating, and the basal macrofossils produced an age of 12,245 ±45 radiocarbon years. The central Kenai Peninsula Lowlands underwent a number of marked vegetational and climatic changes since deglaciation. Four distinct vegetation zones reveal changes starting in the late Pleistocene. The pioneer vegetation includes a dominance of herbaceous ( Artemisia, Apiaceae, Asteroideae)and shrubby ( Betula) species. The second zone (beginning at 9890±45 radiocarbon years) and marking the Holocene boundary, shows a striking increase in Polypodiaceae (ferns) and Picea (spruce) and a decrease in shrubby species such as Betula, indicative of warming. The third zone indicates a decline in Polypodiaceae and a reemergence of Betula species, while the final most recent zone reveals a rapid resurgence in Picea and Tsuga mertensiana (Mountain hemlock) species. While a general warming trend occurred following deglaciation, vegetation patterns suggest extended periods of increased precipitation, for example in the early Holocene, as is evidenced by the plethora of Polypodiaceae. A movement and an intensification of the Aleutian Low could explain these periods of increased precipitation over the Kenai Peninsula. Alternatively, this spike in Polypodiaceae can be explained by increased disturbance. The presence of 10 % Picea pollen at the base of the core suggests that one of the Picea species may have survived the last glaciation in the

  3. 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.

  4. 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.

  5. Bathymetric-based habitat model for yelloweye rockfish (Sebastes ruberrimus) on Alaska's outer Kenai Peninsula

    NASA Astrophysics Data System (ADS)

    Mumm, Joshua D.

    Motivated primarily as part of a habitat-based stock assessment, we explored the feasibility of modeling yelloweye rockfish (Sebastes ruberrimus) habitat in Southcentral Alaska using high-resolution multibeam bathymetry. A generalized linear model was developed with bathymetrically derived terrain metrics (rugosity, slope, bathymetric position index, and distance-to-rock) as predictor variables. The model was parameterized and validated using remotely operated vehicle observations. When evaluated for the Chiswell Island training area, the model correctly classified 96.0% (n = 100) of a reserved set of presence/absence validation points (Cohen's Kappa = 0.92; AUC = 0.98). When evaluated for the independent Nuka Island testing area, the overall accuracy was 82.5% (n=332; Kappa = 0.65; AUC = 0.95). This study demonstrates that suitable yelloweye habitat can be modeled with reasonable accuracy using high-resolution multibeam bathymetry, and such a model is fairly portable among sites along the Kenai Peninsula's outer coast.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  7. 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.

  8. 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

  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. Assessing net community production in a glaciated Alaska fjord

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Coupled terrestrial-glacier-fjord-ocean processes in the Gulf of Alaska and Greenland (Invited)

    NASA Astrophysics Data System (ADS)

    Winsor, P.; Truffer, M.

    2013-12-01

    We present coupled terrestrial-glacier-fjord-ocean system response to changes in forcing from the Gulf of Alaska focusing on the role of glacier runoff on the Alaska Coastal Current. These highly coupled systems remain severely under sampled in time and space, and point to the need for improved sampling techniques of the nearshore environment. We also present detailed measurements from western Greenland consisting of ice-strengthened satellite-tracked surface drifters equipped with CTDs covering the upper 15 m of the ocean deployed in concert with SST surface drifters, ADCPs and shipboard CTD data. This unique data set highlight the complexity of circulation and upper ocean heat and salt content in narrow glacially-dominated fjords.

  16. 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.

  17. 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

  18. 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.

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

    USGS Publications Warehouse

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

    1995-01-01

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

  20. 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

  1. 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.

  2. 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

  3. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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,...

  5. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  7. 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.

  8. 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.

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

    USGS Publications Warehouse

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

    2007-01-01

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

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

    USGS Publications Warehouse

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

    1992-01-01

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

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. An analysis of Late Quaternary eruption frequency as recorded by tephra-fall records from 25 sedge- Sphagnum peat cores recovered from the Kenai Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Deruwe, A.; Wallace, K.; Berg, E.; McDonnell, K.; Loso, M.

    2007-12-01

    Tephra fall (volcanic ash) is considered the principal hazard from Aleutian Arc volcanoes in terms of volume, distribution, and environmental impact. Over sixty percent of Alaska's human population resides in the Cook Inlet region, where ash fall from nearby volcanoes, including Hayes, Spurr/Crater Peak, Redoubt, Iliamna, and Augustine pose the greatest volcanic risk. Alaska's Kenai Peninsula is located generally downwind of Cook Inlet volcanoes (approx. 85 to 400 km) and other active Aleutian Arc volcanoes. Previous studies have shown that Holocene-age tephra fall is well preserved in post-glacial sediments from this region. Such studies have used individual stratigraphic records to estimate tephra-fall frequency on a regional scale, although it is unclear whether those data reflect actual eruption frequency or are biased by paleo-wind direction, basin features, geomorphology, etc. These studies have shown highly discrepant ash-fall frequency records, which may result from the restricted number of study sites (typically one or two), the lack of spatial coverage, and/or the limited preservation potential of a given location. In order to evaluate actual eruption frequency as reflected by tephra fall, our study incorporates a wider geographic range and a greater number of sample locations than previous studies. We recovered and examined 25 sedge- Sphagnum peat cores from a northeast to southwest transect of the Kenai Peninsula, directly parallel to the Cook Inlet volcanoes and covering an area of 8,050 km2 (70 km wide by 115 km long). Magnetic susceptibility (MS), petrographic and electron microprobe analyses, and radiocarbon ages have been utilized to identify, characterize, and correlate tephra deposits among cores. A total of 221 undifferentiated tephra-fall layers are preserved in our cores, of which approximately 80 percent were identified visually and 20 percent were identified by MS peaks and petrographic verification. Eighty AMS radiocarbon ages, ranging from

  17. 75 FR 1404 - Kenai National Wildlife Refuge, Soldotna, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ...We, the U.S. Fish and Wildlife Service (Service), announce the availability of the record of decision (ROD) for the final environmental impact statement (EIS) for Kenai National Wildlife Refuge (NWR, Refuge). The Refuge is located within the Kenai Peninsula Borough, Alaska. We completed a thorough analysis of the environmental, social, and economic considerations and presented it in our final......

  18. Assessing the uncertainty of biomass change estimates obtained using multi-temporal field, lidar sampling, and satellite imagery on the Kenai Peninsula of Alaska (Invited)

    NASA Astrophysics Data System (ADS)

    Andersen, H.

    2013-12-01

    There is increasing interest in the development of statistical sampling designs for aboveground biomass (and carbon) inventory and monitoring programs that can make efficient use of a variety of available data sources, including field plots, airborne lidar sampling, and satellite imagery. While the use of multiple sources, or levels, of remote sensing data can significantly increase the precision of biomass change estimates, especially in remote areas (such as interior Alaska) where it is extremely expensive to establish field plots, it can be challenging to accurately characterize the uncertainty (i.e. variance and bias) of the estimates obtained from these complex multi-level designs. In this study we evaluate a model-based approach to estimate changes in biomass over the western lowlands of the Kenai Peninsula of Alaska during the period 2004-2009 using a combination of field plots, lidar sampling, and satellite imagery. The model-based approach -- where all inferences are conditioned on the model relating the remote-sensing measurements to the inventory parameter of interest (e.g. biomass) - is appropriate for cases where it is cost-prohibitive, or infeasible, to establish a probability sample of field plots that are both spatially and temporally coincident with each remote sensing data set. For example, a model-based approach can be used to obtain biomass estimates over a period of time, even when field data is only available for the current time period. In this study, lidar data were collected in 2004 and 2009 over single swaths that covered 130 Forest Inventory and Analysis (FIA) plots distributed on a regular grid over the entire western Kenai. Field measurements on FIA plots were initially acquired over the period 1999-2003 and fifty-percent of these plots were remeasured in the period 2004-2009. In addition, high-accuracy coordinates (< 1 meter error) were obtained for these FIA plots using survey-grade GLONASS-enabled GPS equipment. Changes in biomass

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

    USGS Publications Warehouse

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

    1990-01-01

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

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 50 CFR Table 14a to Part 679 - Port of Landing Codes 1, Alaska

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Kake 137 KAK Kaltag 310 KAL Kasilof 138 KAS Kenai 139 KEN Kenai River 139 KEN Ketchikan 141 KTN King... report a landing at an Alaska location not currently assigned a location code number, use “Other...

  6. 50 CFR Table 14a to Part 679 - Port of Landing Codes 1, Alaska

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Kake 137 KAK Kaltag 310 KAL Kasilof 138 KAS Kenai 139 KEN Kenai River 139 KEN Ketchikan 141 KTN King... report a landing at an Alaska location not currently assigned a location code number, use “Other...

  7. 50 CFR Table 14a to Part 679 - Port of Landing Codes 1, Alaska

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Kake 137 KAK Kaltag 310 KAL Kasilof 138 KAS Kenai 139 KEN Kenai River 139 KEN Ketchikan 141 KTN King... report a landing at an Alaska location not currently assigned a location code number, use “Other...

  8. 50 CFR Table 14a to Part 679 - Port of Landing Codes 1, Alaska

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Kake 137 KAK Kaltag 310 KAL Kasilof 138 KAS Kenai 139 KEN Kenai River 139 KEN Ketchikan 141 KTN King... report a landing at an Alaska location not currently assigned a location code number, use “Other...

  9. 50 CFR Table 14a to Part 679 - Port of Landing Codes 1, Alaska

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Kake 137 KAK Kaltag 310 KAL Kasilof 138 KAS Kenai 139 KEN Kenai River 139 KEN Ketchikan 141 KTN King... report a landing at an Alaska location not currently assigned a location code number, use “Other...

  10. Parameterization of Heat Transport in a Fjord

    NASA Astrophysics Data System (ADS)

    Hossainzadeh, S.; Tulaczyk, S. M.

    2012-12-01

    We aim to improve the coupling in the Regional Arctic System Model (RASM) between the ocean model, Parallel Ocean Program (POP), and the ice sheet model, Community Ice Sheet Model (CISM), by developing a parameterization for the dominant processes in a typical Greenland fjord. The termini of tidewater glaciers and ice shelves may prove to be a critical forcing on outlet glacier mass balance. Recent studies have shown that warm deep water masses have penetrated far up-stream in fjords and sub-ice shelf cavities. We analyze the effects of bottom bathymetry, entrainment rate at the ice face due to freshwater plumes, surface outflow rates, undulating fjord geometries, and open ocean conditions at the fjord mouth on heat transport up-fjord. The fjord is represented as a two-layer (stratified) open channel flow with a substantial and sudden geometric widening at the mouth. Horizontal force balances as well as mass, salt and heat continuity relations of the upper layer provides an analytical solution for the velocity and thickness distribution along-fjord. Subsequently, the sensitivity of the bottom layer's up-fjord flow and heat transport to the ice face is determined and forms the basis of the parameterization of along-fjord processes. Open ocean scenarios (temperature, salinity and velocity profiles), typical of Arctic oceanographic conditions on the Greenland shelf, are prescribed from results of a coupled ocean-sea ice model configured at a regional scale for the pan-Arctic domain. The model was spun up for 48 years and forced by daily averaged atmospheric reanalysis data from the European Centre for Medium-Range Weather Forecasts. We validate this data from several decades-long time series of in situ data from the Gulf of Alaska and West Greenland. Our results provide ice melt rates which agree with current estimates.

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

    SciTech Connect

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

    1995-11-01

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

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-03

    ...The Kenai Peninsula-Anchorage Borough Resource Advisory Committee will meet in Portage Valley, Alaska. The committee is meeting as authorized under the Secure Rural Schools and Community Self- Determination Act (Pub. L. 110-343) and in compliance with the Federal Advisory Committee Act. The purpose of the meeting is to review and recommend proposed...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. User's guide and data dictionary for Kenai Lakes Investigation Project

    SciTech Connect

    Newell, A.D.; Mitch, M.E.

    1992-03-01

    In 1984, the U.S. Environmental Protection Agency (EPA) implemented the National Surface Water Survey (NSWS) as part of the Aquatic Effects Research Program (AERP). The AERP conducted several integrated studies in areas containing surface waters considered potentially sensitive to change as a result of acidic deposition. The NSWS focused its assessment on lakes and streams located in the contiguous United States. Since the majority of the systems examined in the NSWS receive moderate to high levels of acidic deposition, it is difficult to evaluate the role of natural factors in controlling the chemistry of aquatic ecosystems. Therefore, the EPA implemented a project to collect data on lakes in the Kenai Peninsula of Alaska, an area expected to receive low levels of acidic deposition. The database guide provides a brief overview of the survey and the KLIP database. Detailed information on KLIP results is found in Eilers et al. The document also summarizes the sampling and analytical methods, sources of geographic information, and precision and accuracy results from quality assurance (QA) analysis. The datasets are described in Section 3 and their formats in Section 6. The variables are defined in Section 5, and Appendix A contains a listof the lakes and their chemistry. Appendix B provides reference values taken from the Long Range Transport of Airborne Pollutants (LRTAP) Project audit samples.

  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. 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.

  8. 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

  9. Carbon cycle: Hoard of fjord carbon

    NASA Astrophysics Data System (ADS)

    Keil, Richard

    2015-06-01

    Fjords account for less than 0.1% of the surface of Earth's oceans. A global assessment finds that organic carbon is buried in fjords five times faster than other marine systems, accounting for 11% of global marine organic carbon burial.

  10. USER'S GUIDE AND DATA DICTIONARY FOR KENAI LAKES INVESTIGATION PROJECT

    EPA Science Inventory

    This database guide provides a brief overview of the survey and the Kenai Lakes Investigation Project (KLIP) results is found in Eilers et al (pers. comm.). his document also summarizes the sampling (Section 2.1) and analytical methods (Section 2.3), sources of geographic informa...

  11. Fjord geometry observed in viscous fingering*

    NASA Astrophysics Data System (ADS)

    Thrasher, Matt; Ristroph, Leif; Swinney, Harry L.; Mineev-Weinstein, Mark

    2004-11-01

    Injecting a less viscous fluid (air) into a more viscous fluid (oil) produces an unstable finger of air penetrating into the oil. For sufficiently large forcing, the tip of a finger splits. The region of oil left between adjacent fingers is called a fjord. We characterize the width, widening, and bending of fjords in experiments in a rectangular Hele-Shaw cell. The channel confines air and 50 cS silicone oil between two glass plates, which are 2500 mm long and 250 mm wide with a separation of 0.5 mm. The width of the base of a fjord is found to be approximately one-half of the capillary length scale. From this base, the fjords open with a distribution of angles having a mean of about 9 ^rc, which contradicts theoretical predictions of an opening angle of 0 ^rc (parallel sides). Finally, the centerline of a fjord bends. Lajeunesse and Couder [1] account for the bending of a fjord on a single, one-half width finger. We test the validity of their idea on the tip-splitting of more complicated interfaces and on the widening of fjords. *Supported by ONR [1] E. Lajeunesse and Y. Couder, J. Fluid. Mech. 419, 125 (2000).

  12. 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.

  13. Water renewals in the Saguenay Fjord

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  14. 78 FR 65208 - Modification of Class D and E Airspace; Kenai, AK

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ...This action modifies Class D and E airspace at Kenai Municipal Airport, Kenai, AK. Controlled airspace is necessary to accommodate aircraft using the new Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at the airport. A minor adjustment is made to the geographic coordinates of the airport. Additionally, language establishing dates and times of use......

  15. 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.

  16. 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.

  17. 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.

  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. Suspended particle dynamics and related fjord sedimentation in Kangerlussuaq and Sermilik fjord, SW and SE Greenland

    NASA Astrophysics Data System (ADS)

    Andersen, T. J.; Markussen, T. N.; Nielsen, M. H.; Lund-Hansen, L. C.; Pejrup, M.

    2012-12-01

    Arctic fjords may contain important sedimentary archives reflecting changes in calving, run-off, ice-cover, water temperature etc. In order to be able to do a proper interpretation of the deposited material some knowledge about the deposition-process is required but such information is typically relatively scarce. The present study deals with the sediment transport and particle dynamics in Kangerlussuaq Fjord, W Greenland, and Sermilik Fjord, SE Greenland as well as the sedimentary archive in both fjords. The Kangerlussuaq fjord is likely to contain a sedimentary archive that is primarily influenced by changes in run-off from the inland ice whereas the sedimentation is Sermilik Fjord is expected to primarily reflect changing calving and sea ice conditions. The suspended sediment has been analysed for in situ grain size by use of a laser-diffraction grain-size analyser, LISST-100C, and the settling velocities were determined with a settling tube, model Braystoke SK 110. CTD-profiles were obtained with a Seabird SBE-19 plusV2. The in situ grain sizes were studied both by conventional profiling as well as in a Lagrangian configuration with the LISST-instrument attached to a drifter. Sediment coring will be performed in Sermilik Fjord in August 2012. In Kangerlussuaq Fjord, very fine-grained material, "glacial flour", originating from the inland ice is the only material which is left in suspension in most of the fjord and the SPMC is generally below 5 mg l-1 and decreases to below 1 mg l-1 in the central, deep part of the fjord. LISST-measurements show that this material is aggregated with typical mean floc sizes of 100 - 200 μm. However, the settling tube measurements show that the flocs have settling velocities below 0.02 mm s-1. Based on these results an effective density of only around 3 kg m-3 can be calculated. This is a very low density compared to typical values reported in literature where the lowest values are around 20 kg m-3. The implication of the slow

  20. 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.

  1. Assessing net community production in a glaciated Alaskan fjord

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  2. 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.

  3. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  5. Gulf of Alaska, Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This MODIS true-color image shows the Gulf of Alaska and Kodiak Island, the partially snow-covered island in roughly the center of the image. Credit: Jacques Descloitres, MODIS Land Rapid Response Team

  6. 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.

  7. 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.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  10. 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.

  11. 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

  12. 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

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Kenai Hydro, LLC; Notice of Scoping Meetings, Environmental Site Review, and Soliciting Scoping Comments May 11, 2010. Take notice that the following hydroelectric application has been filed with the Commission and...

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

    USGS Publications Warehouse

    U.S. Geological Survey

    2009-01-01

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

  14. 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.

  15. 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...

  16. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  17. 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...

  18. 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...

  19. 36 CFR 13.1310 - Pets.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Pets. 13.1310 Section 13.1310 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 § 13.1310...

  20. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Snowmachines. 13.1326 Section 13.1326 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...

  1. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  2. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  3. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Climbing and walking on Exit Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National...

  4. 36 CFR 13.1310 - Pets.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Pets. 13.1310 Section 13.1310 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 § 13.1310...

  5. 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...

  6. 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...

  7. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Snowmachines. 13.1326 Section 13.1326 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...

  8. 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...

  9. 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...

  10. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Location of the EGDA. 13.1318 Section 13.1318 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...

  11. 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...

  12. 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...

  13. 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 §...

  14. 36 CFR 13.1310 - Pets.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Pets. 13.1310 Section 13.1310 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 § 13.1310...

  15. 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...

  16. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Climbing and walking on Exit Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National...

  17. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Location of the EGDA. 13.1318 Section 13.1318 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...

  18. 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...

  19. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Snowmachines. 13.1326 Section 13.1326 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...

  20. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Climbing and walking on Exit Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National...

  1. 36 CFR 13.1308 - Harding Icefield Trail.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 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...

  2. 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...

  3. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Snowmachines. 13.1326 Section 13.1326 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...

  4. 36 CFR 13.1326 - Snowmachines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Snowmachines. 13.1326 Section 13.1326 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...

  5. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Food storage. 13.1322 Section 13.1322 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...

  6. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Climbing and walking on Exit Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National...

  7. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Location of the EGDA. 13.1318 Section 13.1318 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...

  8. 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...

  9. 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...

  10. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  11. 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...

  12. 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 §...

  13. 36 CFR 13.1306 - Public use cabins.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  14. 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...

  15. 36 CFR 13.1304 - Ice fall hazard zones.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  16. 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...

  17. 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...

  18. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Location of the EGDA. 13.1318 Section 13.1318 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...

  19. 36 CFR 13.1312 - Climbing and walking on Exit Glacier.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Climbing and walking on Exit Glacier. 13.1312 Section 13.1312 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Kenai Fjords National...

  20. 36 CFR 13.1310 - Pets.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Pets. 13.1310 Section 13.1310 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 § 13.1310...

  1. 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...

  2. 36 CFR 13.1318 - Location of the EGDA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Location of the EGDA. 13.1318 Section 13.1318 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...

  3. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Food storage. 13.1322 Section 13.1322 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...

  4. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Food storage. 13.1322 Section 13.1322 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...

  5. 36 CFR 13.1322 - Food storage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Food storage. 13.1322 Section 13.1322 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...

  6. 36 CFR 13.1310 - Pets.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Pets. 13.1310 Section 13.1310 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 § 13.1310...

  7. 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 §...

  8. 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 §...

  9. 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.

  10. Holocene coastal glaciation of Alaska

    NASA Astrophysics Data System (ADS)

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

    2001-01-01

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

  11. Modelling the Orust fjord system on the Swedish west coast

    NASA Astrophysics Data System (ADS)

    Hansson, Daniel; Stigebrandt, Anders; Liljebladh, Bengt

    2013-03-01

    We use a numerical model to examine the dynamics controlling flushing of the basins of the Orust fjord system on the Swedish west coast over a period of 71 days in the autumn of 2010. This fjord system is known for its seasonal and permanent hypoxic basins; Koljöfjord, Byfjord and Havstensfjord. It is shown that wind direction determines in- and outflows of the basins. Westerly winds result in surface currents towards the interior of the system, and counter currents at the bottom. In contrast, easterly winds cause the export of surface water, which is compensated by upwelling of Skagerrak water. Although these easterly winds cause renewal to take place several times a month in southern Havstensfjord, it occurs only once or twice in the northern part, while Koljöfjord and Byfjord are ventilated about every 3 years. The reduction in density throughout the water column (i.e. weakening of the vertical stratification) is related to the amount of energy being supplied to the deepwater by internal waves, created by barotropic tides across the sills, and wind blowing across the surface. The model shows that, in the southern part of the system, tidal movement dominates the energy supply to the deepwater. Further into the system, the importance of wind energy increases. In Koljöfjord and Byfjord, wind accounts for about 40% of the supplied energy for deepwater mixing. Concurrent weekly measurements taken in each fjord basin reveal that the monthly monitoring programme currently in place cannot adequately resolve the dynamics of the fjords. Modelled and observed currents in Svanesund and Sunninge Strait show prominent baroclinic motion on time-scales between one day and one week, suggesting that monitoring programs that aim to support numerical modelling need to resolve these time scales.

  12. Quantifying flow regimes in a Greenland glacial fjord using iceberg drifters

    NASA Astrophysics Data System (ADS)

    Sutherland, David A.; Roth, George E.; Hamilton, Gordon S.; Mernild, Sebastian H.; Stearns, Leigh A.; Straneo, Fiammetta

    2014-12-01

    Large, deep-keeled icebergs are ubiquitous in Greenland's outlet glacial fjords. Here we use the movement of these icebergs to quantify flow variability in Sermilik Fjord, southeast Greenland, from the ice mélange through the fjord to the shelf. In the ice mélange, a proglacial mixture of sea ice and icebergs, we find that icebergs consistently track the glacier speed, with slightly faster speeds near terminus and episodic increases due to calving events. In the fjord, icebergs accurately capture synoptic circulation driven by both along-fjord and along-shelf winds. Recirculation and in-/out-fjord variations occur throughout the fjord more frequently than previously reported, suggesting that across-fjord velocity gradients cannot be ignored. Once on the shelf, icebergs move southeastward in the East Greenland Coastal Current, providing wintertime observations of this freshwater pathway.

  13. Simulating tsunami propagation in fjords with long-wave models

    NASA Astrophysics Data System (ADS)

    Løvholt, F.; Glimsdal, S.; Lynett, P.; Pedersen, G.

    2015-03-01

    Tsunamis induced by rock slides constitute a severe hazard towards coastal fjord communities. Fjords are narrow and rugged with steep slopes, and modeling the short-frequency and high-amplitude tsunamis in this environment is demanding. In the present paper, our ability (and the lack thereof) to simulate tsunami propagation and run-up in fjords for typical wave characteristics of rock-slide-induced waves is demonstrated. The starting point is a 1 : 500 scale model of the topography and bathymetry of the southern part of Storfjorden fjord system in western Norway. Using measured wave data from the scale model as input to numerical simulations, we find that the leading wave is moderately influenced by nonlinearity and dispersion. For the trailing waves, dispersion and dissipation from the alongshore inundation on the traveling wave become more important. The tsunami inundation was simulated at the two locations of Hellesylt and Geiranger, providing a good match with the measurements in the former location. In Geiranger, the most demanding case of the two, discrepancies are larger. The discrepancies may be explained by a combinations of factors, such as the accumulated errors in the wave propagation along large stretches of the fjord, the coarse grid resolution needed to ensure model stability, and scale effects in the laboratory experiments.

  14. 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.

  15. 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.

  16. 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.

  17. Erosion rates during rapid deglaciation in Icy Bay, Alaska

    NASA Astrophysics Data System (ADS)

    Koppes, MichèLe; Hallet, Bernard

    2006-06-01

    Contemporary glacial erosion rates based on sediment yields in southeast Alaska merit considerable attention because they are unsurpassed worldwide, and they significantly exceed long-term exhumation rates in the region. Two issues are likely to contribute to these high rates: contemporary sediment yields in fjords (1) have generally been overestimated by failing to account for the considerable input of subaerially derived material and (2) are exceptionally high because tidewater glaciers in southeast Alaska have been anomalously dynamic and erosive during the past century of rapid retreat. To investigate these influences and to quantify the rate at which Tyndall Glacier erodes its basin we present seismic data defining the volume of sediments in Taan Fjord, Icy Bay. We subtract the contribution of subaerially derived sediments from the fjord sediment package to determine the sediment yield directly from Tyndall Glacier during the most recent period of retreat: 1962-1999. Using a numerical model of proglacial glacimarine sedimentation, we then calculate the annual sediment yield from, and the corresponding erosion rate of, Tyndall Glacier during this period, which averages 28 ± 5 mma-1. A strong correlation emerges between glacial retreat rates and glacial sediment yields, implying that most contemporary sediment yield data from retreating tidewater glaciers may correspond to contemporary erosion rates that are a factor of 3.5 ± 1.5 higher than in the long term. Hence we estimate the long-term erosion rate for Tyndall Glacier to be 9 ± 2 mma-1.

  18. 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

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

    USGS Publications Warehouse

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

    2007-01-01

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

  20. 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…

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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

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

    USGS Publications Warehouse

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

    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.

  9. An earthquake in Japan caused large waves in Norwegian fjords

    NASA Astrophysics Data System (ADS)

    Schult, Colin

    2013-08-01

    Early on a winter morning a few years ago, many residents of western Norway who lived or worked along the shores of the nation's fjords were startled to see the calm morning waters suddenly begin to rise and fall. Starting at around 7:15 A.M. local time and continuing for nearly 3 hours, waves up to 1.5 meters high coursed through the previously still fjord waters. The scene was captured by security cameras and by people with cell phones, reported to local media, and investigated by a local newspaper. Drawing on this footage, and using a computational model and observations from a nearby seismic station, Bondevik et al. identified the cause of the waves—the powerful magnitude 9.0 Tohoku earthquake that hit off the coast of Japan half an hour earlier.

  10. 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.

  11. 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.

  12. The Holocene Thermal Maximum as a Time of Rapid Peat Accumulation and Peatland Expansion in Alaska

    NASA Astrophysics Data System (ADS)

    Jones, M. C.; Yu, Z.; Peteet, D. M.

    2009-05-01

    High latitudes are particularly sensitive to climate warming resulting from a number of important positive feedbacks, including increasing albedo from changing sea ice extent, snow and vegetation cover, and feedbacks to the carbon cycle. The fate of high latitude ecosystems and associated climate feedbacks in response to warming remains uncertain, particularly in boreal peatlands, which store roughly one-third of the global carbon pool. In order to understand how peatlands respond to climate warming, we examined Holocene carbon accumulation rates from four peatlands on the Kenai Peninsula, Alaska, focusing on the early Holocene (~11,000-9000 cal yr BP), a time when the climate was warmer than today. Basal dates from over 200 peat cores across Alaska were compiled to examine the timing and spatial distribution of peatland initiation across Alaska, and available pollen data from the North American Pollen Database (NAPD) and the Paleoenvironmental Arctic Sciences (PARCS) databases were used to examine associated vegetation distribution patterns. Our study reveals that the highest rates of carbon accumulation on the Kenai Peninsula occurred during the early Holocene Thermal Maximum (HTM), which also corresponds to the highest number of peat basal dates both on the Kenai and across Alaska, indicating that not only vertical peat growth but also lateral peatland expansion was high. We suggest that the warm summers and longer growing season during the early Holocene in Alaska resulted in high net primary productivity (NPP), rapid peat burial, and the greatest carbon accumulation rates. Rapid rates of accumulation and burial may have minimized the effects of aerobic decomposition. In addition, a change in the seasonal timing of precipitation and moisture availability and an increase in summer precipitation may have decreased drought stress, promoting peatland initiation and peat growth. We also speculate that the dominance of broad-leafed deciduous forests and abundant

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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

  1. Characterising fjord circulation patterns and ice flux from time-lapse imagery at Sermilik Fjord, southeast Greenland

    NASA Astrophysics Data System (ADS)

    James, T.; Drocourt, Y. J. R.; Ayoub, F.; Murray, T.; Hughes, A. L. C.

    2014-12-01

    Evidence suggests that the synchronous acceleration and thinning in the early 2000s of Greenland's southeast glaciers were triggered by increased submarine melting. This important control on the region's mass balance is influenced by changes in the strength of coastal currents, which are also believed to be the cause of the subsequent slowdown of the mid-2000s. While warming of the subpolar North Atlantic and increased runoff are blamed for the enhanced submarine melting at the glacier margins, the physical processes that connect them remain largely unknown. Our lack of understanding of coastal currents and associated fluxes is due largely to a lack of observations of a complex system. Typically, data in these regions, if available at all, consist of point measurements at sparse moorings or 2D profiles of a snapshot in time. Here we present a methodology using monoscopic time-lapse imagery to characterise fjord circulation at the mouth of Sermillik Fjord near Helheim Glacier in southeast Greenland. Image resection methods are used to assign a 3D coordinate system to the 6-minute time-lapse images and the movement of icebergs and sea ice are mapped using feature tracking. Along with local wind data, these results will provide much needed information about the patterns of circulation at the fjord's mouth on the surface and at depth, ice fluxes and the influence of wind.

  2. 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.

  3. Linkage of ocean and fjord dynamics at decadal period

    NASA Astrophysics Data System (ADS)

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

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

  4. 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.

  5. 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

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

    PubMed

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

    2015-01-01

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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

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

    PubMed

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

    2012-08-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

  18. 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. PMID:25149564

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. Global Warming and Glaciers Melting at Fjords in Greenland

    NASA Astrophysics Data System (ADS)

    Coelho, Pablo

    2015-04-01

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

  6. Macrofaunal response to phytodetritus in a bathyal Norwegian fjord

    NASA Astrophysics Data System (ADS)

    Sweetman, Andrew K.; Witte, Ursula

    2008-11-01

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

  7. 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..

  8. Double-diffusive layering and mixing in Patagonian fjords

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  9. 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

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  14. Oceanic response to buoyancy, wind and tidal forcing in a Greenlandic glacial fjord

    NASA Astrophysics Data System (ADS)

    Carroll, D.; Sutherland, D.; Shroyer, E.; Nash, J. D.

    2013-12-01

    The Greenland Ice Sheet is losing mass at an accelerating rate. This acceleration may in part be due to changes in oceanic heat transport to marine-terminating outlet glaciers. Ocean heat transport to glaciers depends upon fjord dynamics, which include buoyancy-driven estuarine exchange flow, tides, internal waves, turbulent mixing, and connections to the continental shelf. A 3D model of Rink Isbrae fjord in West Greenland is used to investigate the role of ocean forcing on heat transport to the glacier face. Initial conditions are prescribed from oceanographic field data collected in Summer 2013; wind and tidal forcing, along with meltwater flux, are varied in individual model runs. Subglacial meltwater flux values range from 25-500 m3 s-1. For low discharge values, a subsurface plume drives circulation in the fjord. Our simulations indicate that offshore wind forcing is the dominant mechanism for exchange flow between the fjord and the continental shelf. These results show that glacial fjord circulation is a complex, 3D process with multi-cell estuarine circulation and large velocity shears due to coastal winds. Our results are a first step towards a realistic 3D representation of a high-latitude glacial fjord in a numerical model, and will provide insight to future observational studies.

  15. 43 CFR 2653.7 - Sitka-Kenai-Juneau-Kodiak selections.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) ALASKA NATIVE SELECTIONS... named cities may select not more than one-half the area withdrawn for selection by that corporation....

  16. 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

  17. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  19. 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

  20. 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.

  1. 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.

  2. Geologic framework of lower Cook Inlet, Alaska

    USGS Publications Warehouse

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

    1978-01-01

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

  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. 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…

  6. 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…

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

    USGS Publications Warehouse

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

    1967-01-01

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

  8. 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.

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

    PubMed

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

    2016-08-01

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

  11. 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

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

    PubMed

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

    2012-05-01

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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

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

    PubMed

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

    2015-02-01

    In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment. PMID:24789509

  19. 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.

  20. 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.

  1. 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.

  2. Submarine landforms characteristic of glacier surges in two Spitsbergen fjords

    NASA Astrophysics Data System (ADS)

    Ottesen, D.; Dowdeswell, J. A.; Benn, D. I.; Kristensen, L.; Christiansen, H. H.; Christensen, O.; Hansen, L.; Lebesbye, E.; Forwick, M.; Vorren, T. O.

    2008-08-01

    Well-preserved submarine landforms, all less than 100 years old, are imaged on high-resolution swath bathymetry obtained from Van Keulenfjorden and Rindersbukta (inner Van Mijenfjorden), Spitsbergen, Svalbard. Several tidewater glaciers in these fjords have surged in the last few hundred years. Streamlined landforms, found within the limits of known surges, are interpreted as mega-scale glacial lineations (MSGL) formed subglacially beneath actively surging ice. Large transverse ridges are terminal moraines formed by thrusting at the maximum position of glacier surges. Sediment lobes at the distal margins of terminal moraines are interpreted as glacigenic debris flows, formed either by failure of the frontal slopes of thrust moraines or from deforming sediment extruded from beneath the glacier. Sinuous ridges are eskers, formed after surge termination by the sedimentary infilling of subglacial conduits. Concordant ridges, parallel to former ice margins, are interpreted as minor push moraines, probably formed annually during winter glacier readvance. Discordant ridges, oblique to former ice margins, are interpreted as crevasse-squeeze ridges, forming when soft subglacial sediments are injected into basal crevasses. These submarine landforms have been deposited in the following sequence based on cross-cutting relationships between them, linked to stages of the surge cycle: (1) MSGL; (2a) terminal moraines and (2b) lobe-shaped debris flows; (3) isolated areas of crevasse-fill ridges; (4) eskers and (5) annual retreat ridges. A descriptive landsystem model for tidewater surge-type glaciers has been developed, whose wider applicability is emphasised by comparison with two areas in Isfjorden, Spitsbergen. The model also has a number of features in common with landsystem models for terrestrial surge-type glaciers, but is likely to be more complete since submarine landforms are particularly well preserved. The landforms discussed here may be produced and preserved in

  3. 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.

  4. 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.

  5. 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.

  6. 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.

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

    USGS Publications Warehouse

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

    2016-01-01

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

  8. 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.

  9. 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

  10. Gulf of Alaska Holocene paleoceanography and paleoclimatology from diatom proxies in core EW0408-22JC, Crawfish Inlet, Baranof Island, Alaska.

    NASA Astrophysics Data System (ADS)

    Loofbourrow, C.; Addison, J. A.; Hemphill-Haley, E.

    2014-12-01

    Diatom ecology is used in this study as a paleoceanographic and paleoclimatic proxy for the Eastern Gulf of Alaska. Core EW0408-22JC, an 11.84 m long piston core, was retrieved in 2004 from 188 m water depth in Crawfish Inlet, a deglaciated fjord of Baranof Island, Southeast Alaska, which opens to the eastern Gulf of Alaska (GOA). The core contains a nearly complete Holocene record constrained by 14C and tephrochronology with relatively high sedimentation rates of ~100-200 cm/ky, favorable to high-resolution climate investigations. High-resolution geochemical measurements indicate increasing opal and total organic concentrations and decreasing lithic and CaCO3 concentrations from early to late Holocene. Diatom ecology is quantified by counting of diatom taxa at approximately 170-year stratigraphic intervals, and evaluated for climatic and oceanographic significance using the modern analog technique (MAT) and factor analysis. Diatom proxy variability from this site is inferred to result from changes within the GOA climatic and oceanographic regime. Within this region, the strength and positioning of the Aleutian Low and the Alaska Current influence oceanographic parameters including sea surface temperature, downwelling, and nutrient availability, all of which are reflected in diatom ecology fluctuations. The adjacent North American terrestrial hydroclimate is largely controlled by these factors, and its past conditions are inferred by this reconstruction of GOA paleoceanography and paleoclimatology.

  11. 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.

  12. 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.

  13. 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

  14. Observations of subtidal circulation variability in Sermilik Fjord, Greenland, and its impact on ice-ocean interactions

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    Helheim Glacier, located in southeast Greenland, is a large outlet glacier that drains approximately 10% of the Greenland Ice Sheet (GIS), emptying into Sermilik Fjord. The glacier speed and terminus location have both shown large variability over the past decade, with significant impacts on the freshwater and heat transport within the fjord, as well as on the mass balance of the GIS. Yet the cause for these changes is still debated. Here we present full year time series of velocity and hydrographic observations collected in Sermilik Fjord over 2009-2010, focusing on linking ice-ocean processes directly. The velocity data show that tidal circulation is small inside Sermilik Fjord, with the dominant variability at subtidal timescales. This allows for a more complete description of the fjord circulation than has been possible from inferring the flow from hydrography alone. We then relate the circulation in the fjord to processes directly related to the glacier, including the timing of calving events and iceberg drift. Map of Sermilik Fjord showing the location of field observations made in 2009-2010.

  15. 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).

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

    PubMed

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

    2015-10-01

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

  17. 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.

  18. Modeling iceberg-rafted sedimentation in high-latitude fjord environments

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

    An iceberg model, SedBerg, has been developed to simulate sedimentation in high-latitude glaciated fjords. Sediments deposited in fjords provide an important record of glaciological response to changing climatic conditions. The model simulates the formation, drift, and melt of a population of icebergs utilizing Monte Carlo-based techniques with a number of underlying parametric probability distributions to describe the stochastic behavior of iceberg formation and dynamics. The model captures iceberg dynamics and melt in fjord environments and has been applied to Kangerdlugssuaq Fjord in east Greenland as an example of an iceberg-dominated sedimentary environment. Sedimentation has been simulated over the past 1500 years, encompassing the climatic intervals of the Medieval Warm Period (MWP) and the Little Ice Age (LIA). Model results have been compared with the observed sedimentary record. The model demonstrates that the glaciological regime, e.g., basal debris thickness, mean annual calving rate, mean iceberg size, plays a more important role than the direct influence of climate (ocean and air temperatures) on iceberg sedimentation rate, although often changes in climate result in changes to the glaciological regime.

  19. 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.

  20. Shelf exchange driven by coastal-trapped waves in an Arctic fjord/trough system

    NASA Astrophysics Data System (ADS)

    Inall, Mark; Nilsen, Frank; Cottier, Finlo; Daae, Ragnhild

    2015-04-01

    Ubiquitous and dominant in mid-latitude coastal exchange processes, tides play a relatively minor role in many Arctic fjord and shelf system. Here we show that the class of low frequency (sub-inertial) waves known as coastal-trapped waves (CTWs) play an analogous role to tides in one west Svalbard fjord, and by extension more widely along the west Svalbard and east Greenland margins, where similar conditions prevail. We show that CTWs generated by weather systems passing across the sloping topography of the shelf break propagate into the fjord, steered by the topography of a cross shelf trough. The CTWs have characteristic periods of approximately two days, set by the passage time of weather systems. Phase speeds and wavelengths vary seasonally by a factor of two, according to stratification. Typical winter (summer) values are c = 0.25 ms-1 (0.5 cms-1) and λ = 40 km (84 km). CTW-induced flow velocities in excess of 0.3 ms-1 at 100 m water depth are recorded. Scaled CTW model results indicate that CTW-induced flows may exceed 0.5 ms-1 at the top of the slope. A range of consequences for this dominant mode of sub-inertial variability in Arctic fjord/ocean exchange is discussed, including: generalised geostrophic adjustment, horizontal advection and mixing, resuspension, higher order Stoke's drift effects, and diapycnal mixing via Richardson number instability.

  1. Reconstructing Fjord Circulation Near a Greenland Tidewater Glacier with Physical Modeling and in Situ Mooring Data

    NASA Astrophysics Data System (ADS)

    Schild, K. M.; Hawley, R. L.; Straneo, F.; Cenedese, C.

    2014-12-01

    The rapid speedup of Greenland tidewater glaciers over the last decade, and subsequent mass loss, has been attributed to an increase in air temperature and a synchronous increase in ocean temperatures. The warming subtropical waters previously thought to only exist offshore of Greenland, have been observed throughout most Greenland fjords, and have been suggested to play a large role in submarine melting of the floating glacier terminus and subsequent calving. Warm subtropical water can become entrained by subglacial meltwater as it exits from beneath the glacier. As the buoyant subglacial meltwater moves along the glacier terminus to the surface, the entrained subtropical water contributes to terminus melting and subsequent iceberg melting. However, the impact of a meltwater plume on fjord stratification has been difficult to study due to the limited accessibility of the proglacial environment. We collected a mooring record of salinity and temperature from 2010-2013 at 14 m depth in Sermilik fjord, East Greenland (~25-30 km from the terminus of Helheim Glacier). This record shows a temperature deviation from a sinusoidal seasonal trend between June and October each year; temperatures steadily decrease between June and August and warm again over the subsequent two months. We hypothesize there are three factors driving temperature and salinity changes in the surface waters: (1) subglacial meltwater release, (2) glacier calving, and (3) proglacial circulation. In this study we construct a physical model of the proglacial fjord environment. We modify the quantity, duration and depth of subglacial meltwater release to reconstruct the mooring temperature and salinity records. Results of this study illuminate the influence of subglacial discharge and iceberg melt on proglacial fjord dynamics, an important component in understanding ice sheet- ocean interactions in a warming climate.

  2. 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

  3. 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.

  4. 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)

  5. High-Resolution Glacial Discharge Records From Deep-Water Tidal Rhythmites in an Alaskan Fjord

    NASA Astrophysics Data System (ADS)

    Jackolski, C. L.; Cowan, E. A.; Jaeger, J. M.; Powell, R. D.

    2006-12-01

    In this study we have compiled and analyzed two high-resolution records of deep-water tidal rhythmites derived from glacial discharges. The rhythmites contain an average of 1 cm of sediment thickness per week during the melt-season. Two sediment cores over 17-m-long were collected from Muir Inlet, Glacier Bay National Park, Southeast Alaska, aboard the R/V Maurice Ewing in 2004 (EW0408). One core (core 60JC) was collected just north of the mouth of Wachusett Inlet. The other (core 62JC) was collected 3.8 km due north of 60JC in a separate basin more proximal to Muir and McBride Glaciers. In Glacier Bay, glacial retreat since the Little Ice Age Maximum is well constrained by historical mapping of glacial temini, and local climate records exist as well. The next step after establishing glacial discharge records is to test hypotheses relating glacial discharge to temperature and rainfall. The cores were subsampled with ODP-style u-channels and scanned for magnetic susceptibility and bulk density. X-radiographs of u-channels were collected to observe small-scale (42 microns/pixel) density differences between silt and mud laminae. Spring-neap tidal packages, representing 2-week periods during summer, are visible because of closely-spaced bounding silt laminae. Seasonality is marked by winter gravelly mud (diamicton) beds and/or spring plankton blooms. Spring-neap packages and seasonal markers were considered jointly in order to construct two mostly continuous records of spring-neap packages and melt- season deposits in each core. Secondarily, melt-season duration, which we define as the number of spring- neap packages occurring in a melt-season, was determined. We found that core 60JC extends back 83 years. 75 of those years were identified as having complete, contiguous melt-season deposits that are, on average, 17 cm thick and contain 8.3 spring-neap packages. Core 62JC extends back 62 years. 57 of those years were identified as having complete, contiguous melt

  6. 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

  7. 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

  8. Alaska Library Directory, 1996.

    ERIC Educational Resources Information Center

    Jennings, Mary, Ed.

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

  9. 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.

  10. 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.

  11. 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.

  12. Tephras and the History of Volcanism, Recent Tectonism, and Tsunamis in Lower Cook Inlet, Alaska

    NASA Astrophysics Data System (ADS)

    Davis, K. M.; Beget, D.

    2004-12-01

    Cook Inlet is located on the western side of the Kenai Peninsula in south-central Alaska. Past eruptions from Augustine volcano and other volcanoes have had significant impacts on the lower Cook Inlet communities. Tephra layers from prehistoric and historic eruptions are preserved within peat sequences along Kachemak Bay, near Homer, Alaska. Evidence of active tectonism is found where thick marine muds overlie peat deposits along Kachemak Bay. The marine mud deposits record co-seismic subsidence that occurred during a prehistoric great earthquake on the northern pacific subduction zone. Two layers of sand and beach gravel also occur within the peat deposits. The sedimentology is identical to classic tsunami deposits identified in other tectonically active areas, and we interpret these deposits as evidence of prehistoric tsunamis. The upper sand is directly overlain by a 1.2 cm thick grayish white tephra. The sand and beach gravel associated with the tephra most likely records a tsunami triggered at the nearby Augustine volcano, while the other sand deposit may be evidence of a tectonically triggered tsunami. The recognition of tephras, tsunami deposits, and evidence of prehistoric co-seismic subsidence has significant implications for geohazards in the lower Cook Inlet area.

  13. 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 this…

  14. 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.

  15. 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)

  16. 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.

  17. Libraries in Alaska: MedlinePlus

    MedlinePlus

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

  18. 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

  19. The 2011 Tohoku Tsunami Generated Major Environmental Changes in a Distal Canadian Fjord

    NASA Astrophysics Data System (ADS)

    Thomson, R.; Spear, D.; Rabinovich, A.; Fine, I.; Juhasz, T.

    2014-12-01

    Tsunamis triggered by powerful earthquakes cause extensive damage and loss of life within many regions of the World Ocean. Although coastal inundation from major tsunamis is becoming increasingly well understood, we know little about the broader aspects of such events on distal marine systems. We use time series from moored oceanic sensors to show that the March 2011 Tohoku tsunami generated days of surge-like currents and turbulent mixing in the inner basin of an anoxic fjord located on the west coast of Vancouver Island, British Columbia, more than 7,000 km from the seafloor rupture zone. Mixing, combined with the inflow of more oxygen-rich water from the adjoining outer basin of the fjord, led to abrupt changes in the hydrodynamics, bottom sedimentation, and zooplankton behavior in the basin. These findings help define mechanisms by which major transoceanic tsunamis can significantly alter coastal marine environments located far from the source area.

  20. 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.

  1. 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

  2. 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

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

    NASA Astrophysics Data System (ADS)

    Pawłowska, J.; Zajączkowski, M.; Łącka, M.; Lejzerowicz, F.; Esling, P.; Pawlowski, J.

    2015-08-01

    This paper presents the reconstruction of climate-driven environmental changes of the last millennium from Hornsund Fjord (Svalbard) based on sedimentological and micropalaeontological records. Our palaeo-investigation was supported by the analysis of foraminiferal ancient DNA (aDNA), focusing on non-fossilised monothalamous species. The main climatic fluctuations over the last millennium were the Medieval Warm Period (MWP, 1000-1600 AD), the Little Ice Age (LIA, 1600-1900 AD), and the Modern Warming (MW, 1900 AD-present). Our study indicated that environmental conditions in Hornsund during the MWP and the early LIA (before ~ 1800 AD) were relatively stable, resulting from the distant position of glaciers. The beginning of the LIA (~ 1600 AD) was poorly evidenced by the micropalaeontological record, but well marked in the aDNA data, by an increased proportion of monothalamous foraminifera, especially Bathysiphon sp. The early LIA (~ 1600- ~ 1800 AD) was marked by the increase in abundance of sequences of Hippocrepinella hirudinea and Cedhagenia saltatus. In the late LIA (after ~ 1800 AD), conditions in the fjord became glacier-proximal, characterised 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, major glaciers fronts retreated rapidly to the inner bays, limiting the iceberg discharge to the fjord centre and causing the shift in the foraminiferal community reflected in both fossil and aDNA records. Palaeoceanographic changes in the Hornsund Fjord over the last millennium were driven mainly by the inflow of shelf-originated water masses and glaciers' activity. However, the environmental changes were poorly evidenced in the micropalaeontological record, but well documented in our aDNA data. We considerably increased the number of potential proxy species by including monothalamous foraminifera in the palaeoecological

  4. Paleomagnetic Dating of Holocene Rapidly Deposited Layers From the Saguenay Fjord, Quebec, Canada

    NASA Astrophysics Data System (ADS)

    St-Onge, G.; Mulder, T.; Piper, D. J.; Hillaire-Marcel, C.; Stoner, J. S.

    2006-12-01

    The Saguenay Fjord (Quebec, Canada) area has been struck by several natural disasters in the last 350 years. Among these disasters are the 1663 (M~7) and 1988 (M=6) earthquakes as well as the flood of 1996. These events triggered the deposition of thick layers, ranging from a few centimetres to about sixteen metres in the Saguenay Fjord inner basin. A 38 m-long piston core (core MD99-2222) was sampled from the deepest part of the Saguenay Fjord inner basin as part of the 1999 IMAGES-V (International Marine Past Global Change Study) program in order to determine the frequency of natural hazards such as earthquakes during the Holocene. Based on physical, magnetic and sedimentological data, we identified at least 14 rapidly deposited layers (RDL) in core MD99-2222. These layers contrast sharply from the dark grey bioturbated "background" sediments and are visually recognizable by their light color due to higher CaCO3 content resulting from the incorporation of light grey, slightly calcareous, Laflamme Sea Clays. In addition, most RDL have a sandy base with corresponding peaks in density and magnetic susceptibility, along with generally lower paleomagnetic inclinations that indicate an energetic depositional process where the magnetic particles are plastered horizontally because of high flow velocity and rapid sediment accumulation. Homogeneous, light grey, clayey silt beds generally overlie the sandy bases. Unfortunately, because CaCO3 dissolution occurs in the Saguenay Fjord sediments, little material is available for radiocarbon dating, making the setting of a robust chronology difficult. Here, we will show how changes in the Earth's magnetic field intensity and direction were used, in conjunction with 210Pb dating, one AMS 14C date and the recognition of a turbidite associated with the 1663 earthquake, to construct the age model for core MD99-2222 and thus to date all the RDL.

  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. 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.

  7. 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.

  8. Environmental response of living benthic foraminifera in Kiel Fjord, SW Baltic Sea

    NASA Astrophysics Data System (ADS)

    Nikulina, A.; Polovodova, I.; Schönfeld, J.

    2007-12-01

    The living benthic foraminiferal assemblages in the Kiel Fjord (SW Baltic Sea) were investigated in the years 2005 and 2006. The faunal studies were accomplished by geochemical analyses of surface sediments. In general, sediment pollution by copper, zinc, tin and lead was assessed as moderate in comparison with levels reported from other areas of the Baltic Sea. However, the inner Kiel fjord is still exposed to a high load of metals and organic matter due to enhanced accumulation of fine-grained sediments in conjunction with a concentration of pollution sources as shipyards, harbours and intensive traffic. The results of our survey showed that the dominant environmental forcing of benthic foraminifera is nutrients availability coupled with human impact. A comparison with data from the 1960s revealed apparent changes in species composition and population densities over the past decades. The stress-tolerant species Ammonia beccarii invaded Kiel Fjord whereas Ammotium cassis disappeared, possibly due to low salinity that prevailed 10 years ago. These changes in foraminiferal community and a significant increase of test abnormalities indicate enforced environmental stress since the 1960s.

  9. Foraminiferal response to environmental changes in Kiel Fjord, SW Baltic Sea

    NASA Astrophysics Data System (ADS)

    Nikulina, A.; Polovodova, I.; Schönfeld, J.

    2008-08-01

    The living benthic foraminiferal assemblages in Kiel Fjord (SW Baltic Sea) were investigated in the years 2005 and 2006. The faunal studies were accomplished by geochemical analyses of surface sediments. In general, sediment pollution by copper, zinc, tin and lead is assessed as moderate in comparison with levels reported from other areas of the Baltic Sea. However, the inner Kiel Fjord is still exposed to a high load of metals and organic matter due to enhanced accumulation of fine-grained sediments in conjunction with potential pollution sources as shipyards, harbours and intensive traffic. The results of our survey show that the dominant environmental forcing of benthic foraminifera is nutrients availability coupled with human impact. A comparison with faunal data from the 1960s reveals apparent changes in species composition and population densities. The stress-tolerant species Ammonia beccarii invaded Kiel Fjord. Ammotium cassis had disappeared that reflects apparently the changes in salinity over the last 10 years. These changes in foraminiferal community and a significant increase of test abnormalities indicate an intensified environmental stress since the 1960s.

  10. 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.

  11. 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

  12. 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).

  13. 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

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

    NASA Astrophysics Data System (ADS)

    Stramska, Malgorzata; Jankowski, Andrzej; Cieszyńska, Agata

    2016-04-01

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

  15. Mapping Submarine Groundwater Discharge into Ringkøbing Fjord, Denmark

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  16. 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

  17. Fjord dynamics and glacio-marine interactions on Northern Ellesmere Island, Canada

    NASA Astrophysics Data System (ADS)

    Hamilton, A.; Mueller, D.; Laval, B.

    2012-12-01

    Despite the existence of ice shelves and glacier tongues along the northern coast of Ellesmere Island, Canada, for the majority of the past 4000 years (Evans and England, 1992; Antoniades et al., 2011) recent atmospheric warming has contributed to collapse of the remaining ice shelves and the loss of rare ice-shelf dammed lakes (epishelf lakes) (Mueller et al., 2003, 2008; Copland et al., 2007). These studies have primarily addressed surface processes as the causal factors for ice shelf breakup, but changes in ocean stratification and heat flux, meltwater input, and subglacial thermodynamics may strongly influence the integrity and fate of these systems. Despite the growing evidence of the importance of oceanic processes on tidewater glacier mass balance in Greenlandic fjords (Holland et al., 2008; Johnson et al., 2011; Straneo et al., 2011) these processes remain poorly studied on related systems in the Canadian Arctic Archipelago (CAA). In addition, the recent sharp increase in mass loss from the glaciers and ice caps of the CAA, primarily in the form of meltwater runoff (Gardner et al., 2011) suggest understanding the aquatic and oceanic factors contributing to ice shelf and glacier tongue integrity and epishelf lake formation is critical. We will present observations from the Milne Fjord ice shelf, epishelf lake, and glacier tongue system on the northern coast of Ellesmere Island, Canada (Fig. 1). Two years of field observations include a 15-month under-ice ocean mooring deployment, through-ice oceanographic CTD and current velocity profiles, and ice mass balance estimates from ablation stake and GPR surveys. We will present the first ever observations of the seasonal and episodic oceanographic variations of Milne Fjord, with particular focus on ocean-epishelf lake-ice shelf dynamics. We aim to understand how all ice and ocean components interact to determine the evolution and stability of the system, with the goal of understanding and perhaps predicting large

  18. 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

  19. 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

  20. 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

  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. Flood frequency in Alaska

    USGS Publications Warehouse

    Childers, J.M.

    1970-01-01

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

  3. 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.

  4. 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.

  5. Health status of Mya arenaria bivalves collected from contaminated sites in Canada (Saguenay Fjord) and Denmark (Odense Fjord) during their reproductive period.

    PubMed

    Gagné, F; Blaise, C; Pellerin, J; Pelletier, E; Strand, J

    2006-07-01

    The purpose of this study was to examine the health status and gametogenetic activity in Mya arenaria clams collected at various sites in the St. Lawrence Estuary (Quebec, Canada) and in the Odense Fjord (Denmark). Clam soft tissues were analyzed for metals/metalloids and organotin compounds to confirm their exposure to these contaminants. Their health status was assessed by a test battery of biomarkers designed to measure the early biological effects of contaminants, which include expression of defence mechanisms such as xenobiotic conjugation (glutathione S-transferase), expression of stress proteins (i.e., heme oxygenase and metallothioneins), changes in gametogenetic activity, and individual morphometric characteristics. Clam tissues were also examined for the presence of oxidative damage to lipids, formation of DNA strand breaks, and alterations in heme metabolism. The results showed that clams sampled from sites with either ferry activity or intensive boat traffic in marinas were contaminated by metals/metalloids such as Ag, Al, As, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sn, V, and Zn. The clams also contained relatively high amounts of tributyltin (TBT) in their tissues (in the ng TBT/g range for both areas), with digestive glands containing more organotins than did gonadal tissues. Moreover, clams collected from TBT-contaminated sites had higher amounts of tin-heme adducts and lower total heme in their digestive glands. Condition factor, age distribution, and sex ratio were significantly altered in clams from impacted sites in the Saguenay Fjord and accompanied by an increased male/female sex ratio. Gametogenetic activity was also negatively affected, as revealed by reductions in gonadosomatic index, maturation index, aspartate transcarbamylase activity, and vitellogenin-like proteins. The Saguenay Fjord clams displayed a complex pattern of stress responses and damage such as increased heme oxygenase activity, phase 2 conjugation enzyme activity, lipid

  6. 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.

  7. 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.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  11. 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

  12. 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.

  13. 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.

  14. Estimation of freshwater runoff into Glacier Bay, Alaska and incorporation into a tidal circulation model

    NASA Astrophysics Data System (ADS)

    Hill, D. F.; Ciavola, S. J.; Etherington, L.; Klaar, M. J.

    2009-03-01

    Freshwater discharge is one of the most critical parameters driving water properties within fjord estuarine environments. To date, however, little attention has been paid to the issue of freshwater runoff into Glacier Bay, a recently deglaciated fjord in southeastern Alaska. Estimates of discharge into Glacier Bay and the outlying waters of Icy Strait and Cross Sound are therefore presented. Existing regression equations for southcentral and southeastern coastal Alaska are applied to Glacier Bay to arrive at the estimates. A limited set of acoustic Doppler current profiler (ADCP) measurements generally support the predictions of the regression equations. The results suggest that discharge into the bay ranges from a few hundred to a few thousand m 3 s -1 during a typical year. Peak discharges can be much higher, approximately 10,000 m 3 s -1 for the 10-year flow event. Estimates of the seasonal variation of discharge are also obtained and reveal a broad peak during the summer months. The hydrologic estimates are then coupled with a barotropic tidal circulation model (ADCIRC - ADvanced CIRCulation model) of Glacier Bay waters. This coupling is achieved by treating the entire coastline boundary as a non-zero normal-flux boundary. Numerical simulations with the inclusion of runoff allow for the estimation of parameters such as the estuarine Richardson number, which is an indicator of estuary mixing. Simulations also allow for the comparison of Lagrangian trajectories in the presence and absence of runoff. The results of the present paper are intended to complement a comprehensive and recently-published dataset on the oceanographic conditions of Glacier Bay. The results will also guide continuing efforts to model three-dimensional circulations in the bay.

  15. Analysis of Environmental Forcing and Melange Fluctuation in Asynchronous Retreat of Ocean Terminating Glaciers in Greenland's Sermilik Fjord

    NASA Astrophysics Data System (ADS)

    Seifert, F.; Galey, C. E.; Bassis, J. N.

    2014-12-01

    Widespread near synchronous retreat of marine terminating outlet glaciers has been observed across wide swaths of the Greenland Ice Sheet. However, despite large-scale patterns of retreat, there is considerable variability in the timing and retreat patterns of individual glaciers with geographically adjacent glaciers that experience similar climate and meteorological forcing displaying markedly different behavior. Here we applied an automated identification algorithm that we developed to track the terminus and melange in order better understand the complex dynamics and varying drivers of glacier retreat. The algorithm was applied to three major glaciers (Helheim Glacier, Fenris Glacier and Midgard Glacier) that terminate in Greenland's Sermilik Fjord over the period of 2000- 2014. The terminus position and the percentage of the fjord filled with melange or sea ice from 2001 to present was determined. Since these glaciers exist within the same fjord system, they should experience comparable environmental forcing conditions, but appear to respond to these conditions differently causing them to have varying patterns of retreat. Helheim Glacier and Fenris Glacier have terminus locations closely spaced in the fjord but Helheim Glacier's terminus retreated over 7 km before advancing to stabilize at a 5 km retreat over the observation period and Fenris Glacier's terminus has stayed in roughly the same place. Midgard Glacier is located across the fjord from Helheim Glacier and its terminus has continuously retreated with a retreat of approximately 8 km. This asynchronous retreat shows that proximity alone cannot determine retreat behavior, and a more complex interaction between internal variability and external forcing must be taking place. To better understand the variability within the system and the cause of asynchronous retreat, ocean and air temperature datasets, in conjunction with the fjord geometry, were compared with our derived melange/sea ice and terminus

  16. 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

  17. 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,…

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. Mass movements in fjords caused by seismic activity? A case study from Balsfjord, northern Norway.

    NASA Astrophysics Data System (ADS)

    Forwick, M.; Vorren, T. O.

    2003-04-01

    Fjords can provide excellent opportunities for investigating sedimentary processes related to slope failures. Balsfjord is a 46 km long and maximum 5 km wide fjord in northern Norway, about 10 km south of Tromsø. An end moraine divides the fjord into an Inner and Outer Basin. High-resolution seismic data (3.5 kHz penetration echo sounder), as well as two piston cores, one from each basin, were analysed. The objective of this study was to find submarine deposits that could be used to study the regionality and chronology of postglacial mass-movement activity in northern Norway. Various types of gravity flows were identified, i.e. slumps, debris flows and turbidites. Maximum thickness of one debris flow is c. 15 m. Two marked turbidites have a lateral extent of about 10 km. The origins of some slumps and debris flows include slope failure of the end moraine crossing the fjord, as well as in front of a river mouth. The origin of the turbidites will be studied using grain-size distribution. Three mass-movement events in both basins are correlated using radiocarbon dates. Since these events can be identified in both basins, they are suggested to indicate regional avalanche activity. The three events were bracketed between 9400 radiocarbon years BP and 9100 radiocarbon years BP. This time span fits into the period of most rapid postglacial isostatic uplift in areas adjacent to Balsfjord (Corner and Haugane, 1993). A close correlation between a steep uplift gradient and earthquake frequency/magnitude is suggested by several authors (e.g. Bøe et al., 2001). Thus, seismic activity can be regarded as a potential trigger mechanism for mass-movement activity in Balsfjord. References: Bøe, R., Hovland, M., Instanes, A., Rise, L. and Vasshus, S., 2000. Submarine slide scars and mass movements in Karmsundet and Skudenesfjorden, southwestern Norway: morphology and evolution. Marine Geology, 167(1-2): 147-165. Corner, G.D. and Haugane, E., 1993. Marine-lacustrine stratigraphy of

  3. 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

  4. 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

  5. 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.

  6. 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…

  7. ECOREGIONS OF ALASKA

    EPA Science Inventory

    A map of ecoregions of Alaska has been produced as a framework for organizing and interpreting environmental data for state, national, and international inventory, monitoring, and research efforts. he map and descriptions for 20 ecological regions were derived by synthesizing inf...

  8. Customer Service in Alaska.

    ERIC Educational Resources Information Center

    Ogliore, Judy

    1997-01-01

    Examines how the child support enforcement program in Alaska has responded to the challenges of distance, weather, and cultural differences through training representatives, making waiting areas more comfortable, conducting random customer evaluation of services, establishing travel hubs in regional offices and meeting with community leaders and…

  9. Current Ethnomusicology in Alaska.

    ERIC Educational Resources Information Center

    Johnston, Thomas F.

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

  10. 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.

  11. 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…

  12. 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.

  13. Alaska and Yukon Fires

    Atmospheric Science Data Center

    2014-05-15

    article title:  Smoke Signals from the Alaska and Yukon Fires   ... the Yukon Territory from mid-June to mid-July, 2004. Thick smoke particles filled the air during these fires, prompting Alaskan officials to issue air quality warnings. Some of the smoke from these fires was detected as far away as New Hampshire. These ...

  14. 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)

  15. Marine Derived Nutrients (MDN) in Riverine Ecosystems: Developing Monitoring Tools for Tracking MDN in Alaska Watersheds

    NASA Astrophysics Data System (ADS)

    Rinella, D. J.; Wipfli, M. S.; Walker, C.; Stricker, C. A.

    2005-05-01

    The objective of this study is to measure marine derived nutrient (MDN) presence and effects in stream and riparian habitats on the southern Kenai Peninsula, Alaska. Year 1 approach was to link stream chemistry, marine isotope signatures, and lipid measures along a gradient from headwaters to mouth in watersheds with and without spawning salmon (i.e., N.F. Anchor River and Happy Creek, respectively). The N.F. Anchor River received 13,000 kg of chinook (Oncorhynchus tshawytscha) and 2000 kg of coho (O. kisutch) biomass in 2004. Contrary to our hypothesis, NH4 concentrations were not related to salmon escapement, possibly due to rapid uptake in this apparently phosphorus-rich system. Dolly Varden char (Salvelinus malma), horsetail (Equisetum sp.), and macroinvertebrates collected in spawning reaches showed enriched 15N values relative to an upstream reference and Happy Valley Creek. Biota also showed a general trend toward 15N enrichment along a gradient from headwaters to mouth for both streams, suggesting that trophic complexity increased with stream size regardless of spawning salmon presence. In years 2 and 3 we will expand this study across replicate salmon and non-salmon watersheds and integrate with related studies develop a broader regional understanding of MDN effects in watersheds.

  16. 76 FR 36573 - Public Land Order No. 7770; Extension of Public Land Order No. 6884; Alaska

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

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

  17. Asthma and American Indians/Alaska Natives

    MedlinePlus

    ... Minority Population Profiles > American Indian/Alaska Native > Asthma Asthma and American Indians/Alaska Natives In 2014, 218, ... Native American adults reported that they currently have asthma. American Indian/Alaska Native children are 30% more ...

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

    PubMed

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

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  20. The Hornsund fjord - modeling of the general circulation, heat exchange and water masses transport.

    NASA Astrophysics Data System (ADS)

    Przyborska, Anna; Jakacki, Jaromir; Kosecki, Szymon; Sundfjord, Arild

    2015-04-01

    The MIKE3D hydrodynamic model has been implemented for diagnosis an ecosystem status in the most southern fjord of the Svalbard Archipelago. The model is based on MIKE 3 Flow Model FM that uses flexible mesh grid. The spatial discretization in solutions of equations is performed by the finite element method. The regional scale of the model implicated implementation of external data at the lateral boundary region. In our case Flather's boundary condition let us to force the model with combined information. At the same time tidal ordinate and barotropic component of velocity that reflects the West Spitsbergen Current are implemented. Also salinity and temperature were nested at the boundary area. The upper boundary conditions was also introduced. The data for the boundary were taken from Global Tide Model (all tidal components), an 800 m ROMS simulation of the Svalbard area made by the Norwegian Institute of Marine Research (bartoropic velocities, temperature and salinity), European Centre for Medium Weather Forecast (ECMWF) and also from Global Data Assimilation System (GDAS). Implemented model was validated and the mean circulation and its seasonal variability will be presented. Also influence of the shelf water masses on the fjord will be discussed. Fresh water transport from glaciers, run off and snow will be estimated. Results are based on 5 years simulation (2005-2010) This work was partially performed in the frame of the projects GAME (DEC-2012/04/A/NZ8/00661) and AWAKE2 (Pol-Nor/198675/17/2013)

  1. Norwegian fjord sediments reveal NAO related winter temperature and precipitation changes of the past 2800 years

    NASA Astrophysics Data System (ADS)

    Faust, Johan C.; Fabian, Karl; Milzer, Gesa; Giraudeau, Jacques; Knies, Jochen

    2016-02-01

    The North Atlantic Oscillation (NAO) is the leading mode of atmospheric circulation variability in the North Atlantic region. Associated shifts of storm tracks, precipitation and temperature patterns affect energy supply and demand, fisheries and agricultural, as well as marine and terrestrial ecological dynamics. Long-term NAO records are crucial to better understand its response to climate forcing factors, and assess predictability and shifts associated with ongoing climate change. A recent study of instrumental time series revealed NAO as main factor for a strong relation between winter temperature, precipitation and river discharge in central Norway over the past 50 years. Here we compare geochemical measurements with instrumental data and show that primary productivity recorded in central Norwegian fjord sediments is sensitive to NAO variability. This observation is used to calibrate paleoproductivity changes to a 500-year reconstruction of winter NAO (Luterbacher et al., 2001). Conditioned on a stationary relation between our climate proxy and the NAO we establish a first high resolution NAO proxy record (NAOTFJ) from marine sediments covering the past 2800 years. The NAOTFJ shows distinct co-variability with climate changes over Greenland, solar activity and Northern Hemisphere glacier dynamics as well as climatically associated paleo-demographic trends. The here presented climate record shows that fjord sediments provide crucial information for an improved understanding of the linkages between atmospheric circulation, solar and oceanic forcing factors.

  2. Characterising iceberg scour in diamicton, Scoresby Sund fjord system, East Greenland

    NASA Astrophysics Data System (ADS)

    Linch, Lorna D.; Dowdeswell, Julian A.

    2014-05-01

    Icebergs are major components in shaping polar and sub-polar continental margins, fjords and lakes. When the keel of an iceberg exceeds water depth it ploughs through soft sea/lake sediments gouging out kilometre long scours, 100s of metres wide and tens of metres deep. Because the influence of iceberg scours on sediment is a critical factor when offshore structures (e.g. oil/gas pipelines, power cables) are installed, the surface morphology of iceberg scours on sea/lake beds is relatively well-documented. Less however, is known about sub-scour (i.e. below the sea/lake bed surface) deformation, which is critical to inform i) installation of offshore structures where iceberg scour presents a geohazard, and ii) palaeoenvironmental reconstruction e.g. past ice sheet dynamics, glacial margins, climate etc. Despite advances in numerical modelling and physical testing of sub-scour deformation, such methods are largely still in their infancy, and they are rarely validated using direct empirical evidence of sub-scour deformation. The aim of this research therefore is to macroscopically and microscopically (thin sections) identify the style and intensity of deformation by the ploughing action of iceberg keels in diamictic cores collected from sediments in the heavily iceberg scoured Scoresby Sund fjord system, offshore of East Greenland.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Temperature and resource availability has been suggested to play an important role controlling phytoplankton size structure and productivity. Here we used five independent research cruisers covering the entire Patagonian fjords (41.5-56.0 degress latitude South) to conduct a comparative analysis between zones and to determine the importance of the controlling factors. For the entire Patagonian area phytoplankton size structure seems independent from temperature, but varies with total phytoplankton biomass and productivity. Microphytoplankton contribute with more than 80% in high productivity waters (chlorophyll-a higher than 5 μg L-1) and picophytoplankton dominates when chlorophyll-a is lower than 1 μg L-1. In addition, NO3:Si(OH)4 ratio control phytoplankton size structure, where a large decrease in Si(OH)4 from north to south Patagonia (from 20 to 0.1 mM average, respectively) seems to be a major factor of control. Major and prolonged effects expected in fjord areas, such as anthropogenic eutrophication and global warning, may modify the observed relationships leading to important changes in the phytoplankton community and its ecological role.

  4. Laboratory investigations of granular and hydrodynamic processes in tidewater glacial fjords

    NASA Astrophysics Data System (ADS)

    Cathles, Mac; Thompson, Oluwatoyin; Burton, Justin

    Accelerated warming in the past few decades has led to a dramatic increase in glacial activity. This is perhaps most apparent in tidewater glacial fjords, where gravitational flows from ice sheets are focused into narrow channels of thick, fast-flowing ice which terminate into the ocean. The result is a complex system involving both melting and iceberg calving which has a direct impact on the Earth's climate and sea level rise. However, there are numerous inherent difficulties in collecting field data from remote, ice-choked fjords. To address this, we use a laboratory scale model to measure aspects of tidewater glaciers which are not observable in nature. Our model has helped to uncover the source of glacial earthquakes, where floating, cubic-kilometer scaled icebergs capsize due to gravitational instability, and temporarily reverse the velocity of the glacier. In addition, we use our model to address two other important components of tidewater glaciers involving a granular ice mélange which applies stresses on the glacier, and the role of iceberg capsize in disrupting the stratified heat transport at the glacier's terminus. We acknowledge support from NSF DMR-1506446.

  5. Circulation induced by subglacial discharge in glacial fjords: Results from idealized numerical simulations

    NASA Astrophysics Data System (ADS)

    Salcedo-Castro, Julio; Bourgault, Daniel; deYoung, Brad

    2011-09-01

    The flow caused by the discharge of freshwater underneath a glacier into an idealized fjord is simulated with a 2D non-hydrostatic model. As the freshwater leaves horizontally the subglacial opening into a fjord of uniformly denser water it spreads along the bottom as a jet, until buoyancy forces it to rise. During the initial rising phase, the plume meanders into complex flow patterns while mixing with the surrounding fluid until it reaches the surface and then spreads horizontally as a surface seaward flowing plume of brackish water. The process induces an estuarine-like circulation. Once steady-state is reached, the flow consists of an almost undiluted buoyant plume rising straight along the face of the glacier that turns into a horizontal surface layer thickening as it flows seaward. Over the range of parameters examined, the estuarine circulation is dynamically unstable with gradient Richardson number at the sheared interface having values of <1/4. The surface velocity and dilution factors are strongly and non-linearly related to the Froude number. It is the buoyancy flux that primarily controls the resulting circulation with the momentum flux playing a secondary role.

  6. Simulating the uncertain effect of active carbon capping of a dioxin-polluted Norwegian fjord.

    PubMed

    Starrfelt, Jostein; Saloranta, Tuomo M

    2015-07-01

    Process-based multimedia models are frequently used to simulate the long-term impacts of pollutants and to evaluate potential remediation actions that can be put in place to improve or manage polluted marine environments. Many such models are detailed enough to encapsulate the different scales and processes relevant for various contaminants, yet still are tractable enough for analysis through established methods for uncertainty assessment. Inclusion and quantification of the uncertainty associated with local efficacy of remediation actions is of importance when the desired outcome in terms of human health concerns or environmental classification shows a nonlinear relationship with remediation effort. We present an updated fugacity-based environmental fate model set up to simulate the historical fate of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) in the Grenland fjords, in Norway. The model is parameterized using Bayesian inference and is then used to simulate the effect of capping parts of the polluted sediments with active carbon. Great care is taken in quantifying the uncertainty regarding the efficacy of the activated carbon cap to reduce the leaching of contaminants from the sediments. The model predicts that by capping selected parts of the fjord, biota will be classified as moderately polluted approximately a decade earlier than a natural remediation scenario. Our approach also illustrates the importance of incorporating uncertainty in local remediation efforts, as the biotic concentrations scale nonlinearly with remediation effort. PMID:25641901

  7. 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.

  8. Shrubline but not treeline advance matches climate velocity in montane ecosystems of south-central Alaska.

    PubMed

    Dial, Roman J; Scott Smeltz, T; Sullivan, Patrick F; Rinas, Christina L; Timm, Katriina; Geck, Jason E; Carl Tobin, S; 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

  9. 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

  10. Seasonal variation in methane emissions from an interior Alaska thermokarst lake

    NASA Astrophysics Data System (ADS)

    Strohm, A. J.; Walter Anthony, K.; Thalasso, F.; Sepulveda-Jauregui, A.; Martinez Cruz, K. C.; Dove, K. L.

    2011-12-01

    Refining our knowledge of methane cycling in aquatic ecosystems and their emissions to the atmosphere is important for understanding their role in climate change. The contribution of northern high latitude lakes to terrestrial methane emissions has recently been recognized as significant, and is likely to contribute a positive feedback to increasing atmospheric temperatures. The data available for accurately defining seasonal and net annual methane emissions from northern high latitude lakes are presently limited by a seasonal imbalance in both gross and net production measurements, as well as a poor understanding of emissions pathways and geographic differences. To help fill in some of these data gaps, we conducted intensive year-round measurement of ebullition and diffusive methane flux from Goldstream Lake (informal name), a thermokarst lake in central Alaska. Additionally, we made less frequent measurements on 47 lakes in winter and summer along a latitudinal transect in Alaska from the Kenai Peninsula to Prudhoe Bay. We used several methods to measure methane flux over multiple seasons in order to better understand complexity in the fate and transport of methane. These include (i) static chamber measurements of seep ebullition, (ii) documentation of the fate of gas trapped in winter ice, (iii) dissolved gas measurements by both gas chromatography and Tunable Diode Laser Absorption Spectroscopy, and(iv) measurement of methane concentration in air above the lake surface by a LiCor 7700 Open Path Methane Analyzer. Of specific interest was seasonal variation in methane emissions and the fate of winter methane production, whose release to the atmosphere is restricted for seven months by increasingly thick ice cover.

  11. 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.

  12. 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. PMID:25426419

  13. Mid-summer mesozooplankton biomass, its size distribution, and estimated production within a glacial Arctic fjord (Hornsund, Svalbard)

    NASA Astrophysics Data System (ADS)

    Trudnowska, E.; Basedow, S. L.; Blachowiak-Samolyk, K.

    2014-09-01

    The estimation of secondary production constitutes an integrating proxy of pelagic ecosystem status, its functions as well as its responses to environmental stressors. The combination of high-resolution automatic measurements with a Laser Optical Plankton Counter (LOPC) and size spectrum analyses was utilized to estimate the secondary production of a high Arctic fjord during a summer post bloom situation in 2012. The dataset comprised 28 vertical and extensive horizontal hauls of a LOPC-CTD-fluorometer platform plus four zooplankton net sampling stations for taxonomic composition designation. A clear gradient in temperature, salinity, chlorophyll a concentrations as well as mesozooplankton abundance, biomass and production was demonstrated along Hornsund fjord axis. The outer fjord part was under the influence of water advection and had the highest chlorophyll a concentrations, numerous opaque mesozooplankton individuals and flat slopes of size spectra, pointing to long food chains in which biomass is recycled several times. The opposite state was found in the glacial bays, where the glacier meltwater discharge led to low chlorophyll a concentrations but high abundance of small and amorphous particles. It resulted in steep size spectra slopes and high intercepts implying higher potential productivity there. The model of mesozooplankton production demonstrated that Hornsund fjord is a highly productive ecosystem, particularly its upper water layer and its central parts. However, we would like to emphasize that a careful approach is needed before going deeper into ecological interpretations based on size spectra analysis, especially in reservoirs, where non-zooplankton particles contribute to the size spectra.

  14. Genome sequence of "Candidatus Aquiluna" sp. strain IMCC13023, a marine member of the Actinobacteria isolated from an arctic fjord.

    PubMed

    Kang, Ilnam; Lee, Kiyoung; Yang, Seung-Jo; Choi, Ahyoung; Kang, Dongmin; Lee, Yoo Kyoung; Cho, Jang-Cheon

    2012-07-01

    We report the genome sequence of actinobacterial strain IMCC13023, isolated from arctic fjord seawater. Phylogenetic analysis of 16S rRNA gene showed that the strain is related to "Candidatus Aquiluna rubra." The genome information suggests that strain IMCC13023 is a photoheterotroph carrying actinorhodopsin, with the smallest genome ever reported for a free-living member of the Actinobacteria. PMID:22689238

  15. Bathymetry data reveal glaciers vulnerable to ice-ocean interaction in Uummannaq and Vaigat glacial fjords, west Greenland

    NASA Astrophysics Data System (ADS)

    Rignot, E.; Fenty, I.; Xu, Y.; Cai, C.; Velicogna, I.; Cofaigh, C. Ó.; Dowdeswell, J. A.; Weinrebe, W.; Catania, G.; Duncan, D.

    2016-03-01

    Marine-terminating glaciers play a critical role in controlling Greenland's ice sheet mass balance. Their frontal margins interact vigorously with the ocean, but our understanding of this interaction is limited, in part, by a lack of bathymetry data. Here we present a multibeam echo sounding survey of 14 glacial fjords in the Uummannaq and Vaigat fjords, west Greenland, which extends from the continental shelf to the glacier fronts. The data reveal valleys with shallow sills, overdeepenings (>1300 m) from glacial erosion, and seafloor depths 100-1000 m deeper than in existing charts. Where fjords are deep enough, we detect the pervasive presence of warm, salty Atlantic Water (AW) (>2.5°C) with high melt potential, but we also find numerous glaciers grounded on shallow (<200 m) sills, standing in cold (<1°C) waters in otherwise deep fjords, i.e., with reduced melt potential. Bathymetric observations extending to the glacier fronts are critical to understand the glacier evolution.

  16. Significant Alaska minerals

    SciTech Connect

    Robinson, M.S.; Bundtzen, T.K.

    1982-01-01

    Alaska ranks in the top four states in gold production. About 30.5 million troy oz have been produced from lode and placer deposits. Until 1930, Alaska was among the top 10 states in copper production; in 1981, Kennecott Copper Company had prospects of metal worth at least $7 billion. More than 85% of the 20 million oz of silver derived have been byproducts of copper mining. Nearly all lead production has been as a byproduct of gold milling. Molybdenum is a future Alaskan product; in 1987 production is scheduled to be about 12% of world demand. Uranium deposits discovered in the Southeast are small but of high grade and easily accessible; farther exploration depends on improvement of a depressed market. Little has been done with Alaskan iron and zinc, although large deposits of the latter were discovered. Alaskan jade has a market among craftspeople. A map of the mining districts is included. 2 figures, 1 table.

  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. Aniakchak Crater, Alaska Peninsula

    USGS Publications Warehouse

    Smith, Walter R.

    1925-01-01

    The discovery of a gigantic crater northwest of Aniakchak Bay (see fig. 11) closes what had been thought to be a wide gap in the extensive series of volcanoes occurring at irregular intervals for nearly 600 miles along the axial line of the Alaska Peninsula and the Aleutian Islands. In this belt there are more active and recently active volcanoes than in all the rest of North America. Exclusive of those on the west side of Cook Inlet, which, however, belong to the same group, this belt contains at least 42 active or well-preserved volcanoes and about half as many mountains suspected or reported to be volcanoes. The locations of some of these mountains and the hot springs on the Alaska Peninsula and the Aleutian Islands are shown on a map prepared by G. A. Waring. Attention has been called to these volcanoes for nearly two centuries, but a record of their activity since the discovery of Alaska is far from being complete, and an adequate description of them as a group has never been written. Owing to their recent activity or unusual scenic beauty, some of the best known of the group are Mounts Katmai, Bogoslof, and Shishaldin, but there are many other beautiful and interesting cones and craters.

  19. Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords

    PubMed Central

    Ferrada-Fuentes, Sandra; Galleguillos, Ricardo; Hernández, Cristián E.

    2016-01-01

    Marine environmental variables can play an important role in promoting population genetic differentiation in marine organisms. Although fjord ecosystems have attracted much attention due to the great oscillation of environmental variables that produce heterogeneous habitats, species inhabiting this kind of ecosystem have received less attention. In this study, we used Sprattus fuegensis, a small pelagic species that populates the inner waters of the continental shelf, channels and fjords of Chilean Patagonia and Argentina, as a model species to test whether environmental variables of fjords relate to population genetic structure. A total of 282 individuals were analyzed from Chilean Patagonia with eight microsatellite loci. Bayesian and non-Bayesian analyses were conducted to describe the genetic variability of S. fuegensis and whether it shows spatial genetic structure. Results showed two well-differentiated genetic clusters along the Chilean Patagonia distribution (i.e. inside the embayment area called TicToc, and the rest of the fjords), but no spatial isolation by distance (IBD) pattern was found with a Mantel test analysis. Temperature and nitrate were correlated to the expected heterozygosities and explained the allelic frequency variation of data in the redundancy analyses. These results suggest that the singular genetic differences found in S. fuegensis from inside TicToc Bay (East of the Corcovado Gulf) are the result of larvae retention bya combination of oceanographic mesoscale processes (i.e. the west wind drift current reaches the continental shelf exactly in this zone), and the local geographical configuration (i.e. embayment area, islands, archipelagos). We propose that these features generated an isolated area in the Patagonian fjords that promoted genetic differentiation by drift and a singular biodiversity, adding support to the existence of the largest marine protected area (MPA) of continental Chile, which is the Tic-Toc MPA. PMID:27505009

  20. Genetic Structure in a Small Pelagic Fish Coincides with a Marine Protected Area: Seascape Genetics in Patagonian Fjords.

    PubMed

    Canales-Aguirre, Cristian B; Ferrada-Fuentes, Sandra; Galleguillos, Ricardo; Hernández, Cristián E

    2016-01-01

    Marine environmental variables can play an important role in promoting population genetic differentiation in marine organisms. Although fjord ecosystems have attracted much attention due to the great oscillation of environmental variables that produce heterogeneous habitats, species inhabiting this kind of ecosystem have received less attention. In this study, we used Sprattus fuegensis, a small pelagic species that populates the inner waters of the continental shelf, channels and fjords of Chilean Patagonia and Argentina, as a model species to test whether environmental variables of fjords relate to population genetic structure. A total of 282 individuals were analyzed from Chilean Patagonia with eight microsatellite loci. Bayesian and non-Bayesian analyses were conducted to describe the genetic variability of S. fuegensis and whether it shows spatial genetic structure. Results showed two well-differentiated genetic clusters along the Chilean Patagonia distribution (i.e. inside the embayment area called TicToc, and the rest of the fjords), but no spatial isolation by distance (IBD) pattern was found with a Mantel test analysis. Temperature and nitrate were correlated to the expected heterozygosities and explained the allelic frequency variation of data in the redundancy analyses. These results suggest that the singular genetic differences found in S. fuegensis from inside TicToc Bay (East of the Corcovado Gulf) are the result of larvae retention bya combination of oceanographic mesoscale processes (i.e. the west wind drift current reaches the continental shelf exactly in this zone), and the local geographical configuration (i.e. embayment area, islands, archipelagos). We propose that these features generated an isolated area in the Patagonian fjords that promoted genetic differentiation by drift and a singular biodiversity, adding support to the existence of the largest marine protected area (MPA) of continental Chile, which is the Tic-Toc MPA. PMID:27505009

  1. Exploring the Diversity and Antimicrobial Potential of Marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile

    PubMed Central

    Undabarrena, Agustina; Beltrametti, Fabrizio; Claverías, Fernanda P.; González, Myriam; Moore, Edward R. B.; Seeger, Michael; Cámara, Beatriz

    2016-01-01

    Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although, Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae, and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera) was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus, and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium, and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%), PKS I (18%), and PKS II (73%). Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds. PMID:27486455

  2. Exploring the Diversity and Antimicrobial Potential of Marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile.

    PubMed

    Undabarrena, Agustina; Beltrametti, Fabrizio; Claverías, Fernanda P; González, Myriam; Moore, Edward R B; Seeger, Michael; Cámara, Beatriz

    2016-01-01

    Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although, Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae, and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera) was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus, and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium, and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%), PKS I (18%), and PKS II (73%). Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds. PMID:27486455

  3. Analyses of past and present rock slope instabilities in a fjord valley: Implications for hazard estimations

    NASA Astrophysics Data System (ADS)

    Böhme, M.; Oppikofer, T.; Longva, O.; Jaboyedoff, M.; Hermanns, R. L.; Derron, M.-H.

    2015-11-01

    For quantitative hazard assessment it is necessary to define the magnitude-frequency distribution and a temporal model of the landslide frequency. This is often complicated for large rock slope failures due to the lack of significant numbers of large rock slope failures in inventories of a given homogeneous region or sparse information about the timing. An inventory of 108 rock slope failure deposits within the fjords of the Storfjord region including a relative rockslide chronostratigraphy was available for this study. The temporal distribution of rock slope failures is characterized by a rapid response with a high frequency of failures directly after deglaciation followed by a lower constant frequency since 9,000 years BP for the entire Storfjord region. The largest recorded volumes failed directly after deglaciation. Volumes larger than 5 × 106 m3 have not been recorded within the last 9,000 years. In addition, 17 rockslide scars and on the other hand 17 potential rock slope instabilities have been mapped at the northeastern flank of Tafjord, which is a branch of the Storfjord. Volume-frequency relations have been developed for the three inventories from Tafjord, comprising (i) fjord deposits, (ii) rockslide scars and (iii) potential instabilities. They result in very similar distributions over the entire volume range. All three inventories are underlying the same processes that lead to destabilisation and finally failure. Additionally, the compilation of the three inventories is independent and based on different methodologies. The similarity of the volume-frequency distributions is thus verifying the different inventories. Hence the obtained volume-frequency relation can be used to assess the rockslide hazard for the study area. Present day annual expectable frequencies for different volume classes have been assessed based on the obtained volume-frequency relation of the fjord deposits. For example, the average annual frequency for rock slope failures of V

  4. Alaska's Children, 2000. Alaska Head Start State Collaboration Project. Quarterly Report.

    ERIC Educational Resources Information Center

    Douglas, Dorothy, Ed.

    2000-01-01

    This document consists of the two 2000 issues of "Alaska's Children," which provides information on the Alaska Head Start State Collaboration Project and updates on Head Start activities in Alaska. Regular features include a calendar of conferences and meetings, a status report on Alaska's children, reports from the Alaska Children's Trust, and…

  5. 78 FR 53137 - Flint Hills Resources Alaska, LLC, BP Pipelines (Alaska) Inc., ConocoPhillips Transportation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ... formal complaint against BP Pipelines (Alaska) Inc., ConocoPhillips Transportation Alaska, Inc., and... Energy Regulatory Commission Flint Hills Resources Alaska, LLC, BP Pipelines (Alaska) Inc., ConocoPhillips Transportation Alaska, Inc., ExxonMobil Pipeline Company; Notice of Complaint Take notice that...

  6. Rural Alaska Mentoring Project (RAMP)

    ERIC Educational Resources Information Center

    Cash, Terry

    2011-01-01

    For over two years the National Dropout Prevention Center (NDPC) at Clemson University has been supporting the Lower Kuskokwim School District (LKSD) in NW Alaska with their efforts to reduce high school dropout in 23 remote Yup'ik Eskimo villages. The Rural Alaska Mentoring Project (RAMP) provides school-based E-mentoring services to 164…

  7. Alaska Native Land Claims. [Textbook].

    ERIC Educational Resources Information Center

    Arnold, Robert D.; And Others

    Written for students at the secondary level, this textbook on Alaska Native land claims includes nine chapters, eight appendices, photographs, maps, graphs, bibliography, and an index. Chapters are titled as follows: (1) Earliest Times (Alaska's first settlers, eighteenth century territories, and other claimants); (2) American Indians and Their…

  8. Preparing Teachers for Rural Alaska.

    ERIC Educational Resources Information Center

    Barnhardt, Ray

    1999-01-01

    This article discusses preparing teachers to teach in rural Alaska. An anecdote illustrates how outsiders who come to work in rural Alaska get into trouble because they are unprepared for conditions unique to the North. These conditions end up being viewed as impediments rather than opportunities. The same is true for the field of education. Of…

  9. A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem

    PubMed Central

    Harwell, Mark A.; Gentile, John H.; Cummins, Kenneth W.; Highsmith, Raymond C.; Hilborn, Ray; McRoy, C. Peter; Parrish, Julia; Weingartner, Thomas

    2010-01-01

    Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems. PMID:20862192

  10. A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem.

    PubMed

    Harwell, Mark A; Gentile, John H; Cummins, Kenneth W; Highsmith, Raymond C; Hilborn, Ray; McRoy, C Peter; Parrish, Julia; Weingartner, Thomas

    2010-07-01

    Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems. PMID:20862192

  11. Meltwater and tidal currents: Controls on circulation in a small glacial fjord

    NASA Astrophysics Data System (ADS)

    Cowan, Ellen A.

    1992-04-01

    McBride Inlet is a small glacial fjord that receives freshwater from a submarine tunnel at the base of a tidewater glacier at its head. The upwelling buoyant plume mixes with basin water, lowering the salinity throughout the ice-proximal basin. Freshwater also upwells from the melting ice face but the effects are only important in winter when discharge is low. Deep water renewal occurs in summer because the water mass crossing the sill inward is denser than the deep basin water. The thick, low velocity surface layer is affected by tides and wind, producing a slow moving gyre near the glacier. Meltwater discharge from a submarine position and the resultant circulation in McBride Inlet result in extremely high ice-proximal sedimentation rates.

  12. Biological effects of long term fine limestone tailings discharge in a fjord ecosystem.

    PubMed

    Brooks, Lucy; Melsom, Fredrik; Glette, Tormod

    2015-07-15

    Benthic infaunal data collected from 1993 to 2010 were analysed to examine the effect of long term discharge of fine limestone tailings on macrofaunal species assemblages in a fjord. Relative distance from the outfall and proportion of fine tailings in the sediment were correlated with benthic community structure. Diversity decreased with increasing proportion of fine tailings. Biological Traits Analysis (BTA) was used to explore the temporal and spatial effects of the tailings gradient on macrofaunal functional attributes. BTA revealed that all stations along a pressure gradient of fine limestone tailings were dominated by free-living species. As the proportion of fine tailings in the sediment increased, there was an increase in fauna that were smaller, highly mobile, living on or nearer the surface sediment, with shorter lifespans. There was a decrease in permanent tube dwellers, those fauna with low or no mobility, that live deeper in the sediment and have longer lifespans (>5 yrs). PMID:25960275

  13. Population dynamics and parasitation of planktonic and epibenthic crustaceans in the Baltic Schlei fjord

    NASA Astrophysics Data System (ADS)

    Gollasch, S.; Zander, C. D.

    1995-03-01

    The planktonic and epibenthic crustacean fauna from two sites of the brackish Schlei fjord, Northern Germany, was investigated over a six-month period. Calanoid and cyclopoid copepods were more abundant in lower salinities, whereas, benthic decapods, isopods and amphipods prevailed in the site of higher salinity. Cestodan larvae were found only in spring which may be due to the timing of the respective life-cycles. Parasites of benthic crustaceans, mostly digenean metacercariae but also cestodans, acanthocephalans and nematodes, appeared from spring to late summer. Decreasing salinities caused lower intensities of the most abundant parasite, Maritrema subdolum; only the true brackish-water species among the hosts were more heavily infested than those found in higher salinities. The correlation of parasite size and host size at infestation became apparent. Therefore, Crangon crangon is an optimal host for the large Podocotyle atomon metacercariae. Coevolutive trends between some hosts and parasites are made evident.

  14. The 2011 Tohoku tsunami generated major environmental changes in a distal Canadian fjord

    NASA Astrophysics Data System (ADS)

    Thomson, Richard E.; Spear, David J.; Rabinovich, Alexander B.; Juhász, Tamás. A.

    2013-11-01

    triggered by powerful earthquakes cause extensive damage and loss of life within many regions of the World Ocean. Although coastal inundation from major tsunamis is becoming increasingly well understood, we know little about the broader aspects of such events on distal marine systems. Here we use time series from moored oceanic sensors to show that the Tohoku tsunami generated by the magnitude 9.0 earthquake off eastern Japan in March 2011 caused days of surge-like currents and turbulent mixing in the inner basin of an anoxic Canadian fjord located over 7000 km from the seafloor rupture zone. Mixing, combined with the inflow of more oxygen-rich water from the adjoining outer basin, led to abrupt changes in the hydrodynamics, bottom sedimentation, and zooplankton behavior in the basin. These findings help define mechanisms by which major transoceanic tsunamis can significantly alter coastal marine environments located far from the source area.

  15. Numerical modeling experiments of coastal upwelling at the field of Arctic fjords.

    NASA Astrophysics Data System (ADS)

    Kosecki, Szymon; Dzierzbicka-Głowacka, Lidia

    2016-04-01

    Coastal upwelling is a well described, known phenomenon in theory. Nowadays there is more and more both environmental and modeling studies about it. Upwelling especially in the Arctic fjords is a process that strongly affects hydrodynamics and even more ecosystems. It is so important, that it brings detailed question about effects and needed wind driven forcing parameters. My modeling experiment studies were strongly different than the studies that are typically carried out using numerical models. Instead of searching for this phenomenon in modeled analysis or environmental data, I did several case scenarios simulations. For those I used statistically selected wind data measured in-stiu. The hi-resolution coastal mapping, the flexible mesh discretization method and the sigma-layered three dimensional model MIKE 3 by DHI allowed me to explore this phenomenon with very good accuracy. This studies have been done in Institute of Oceanology PAS in Sopot, as a part of Centre for Polar Studies.

  16. GeoFORCE Alaska, A Successful Summer Exploring Alaska's Geology

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2012-12-01

    Thirty years old this summer, RAHI, the Rural Alaska Honors Institute is a statewide, six-week, summer college-preparatory bridge program at the University of Alaska Fairbanks for Alaska Native and rural high school juniors and seniors. This summer, in collaboration with the University of Texas Austin, the Rural Alaska Honors Institute launched a new program, GeoFORCE Alaska. This outreach initiative is designed to increase the number and diversity of students pursuing STEM degree programs and entering the future high-tech workforce. It uses Earth science to entice kids to get excited about dinosaurs, volcanoes and earthquakes, and includes physics, chemistry, math, biology and other sciences. Students were recruited from the Alaska's Arctic North Slope schools, in 8th grade to begin the annual program of approximately 8 days, the summer before their 9th grade year and then remain in the program for all four years of high school. They must maintain a B or better grade average and participate in all GeoFORCE events. The culmination is an exciting field event each summer. Over the four-year period, events will include trips to Fairbanks and Anchorage, Arizona, Oregon and the Appalachians. All trips focus on Earth science and include a 100+ page guidebook, with tests every night culminating with a final exam. GeoFORCE Alaska was begun by the University of Alaska Fairbanks in partnership with the University of Texas at Austin, which has had tremendous success with GeoFORCE Texas. GeoFORCE Alaska is managed by UAF's long-standing Rural Alaska Honors Institute, that has been successfully providing intense STEM educational opportunities for Alaskan high school students for over 30 years. The program will add a new cohort of 9th graders each year for the next four years. By the summer of 2015, GeoFORCE Alaska is targeting a capacity of 160 students in grades 9th through 12th. Join us to find out more about this exciting new initiative, which is enticing young Alaska Native

  17. 2013 Alaska Performance Scholarship Outcomes Report

    ERIC Educational Resources Information Center

    Rae, Brian

    2013-01-01

    In accordance with Alaska statute the departments of Education & Early Development (EED) and Labor and Workforce Development (DOLWD), the University of Alaska (UA), and the Alaska Commission on Postsecondary Education (ACPE) present this second annual report on the Alaska Performance Scholarship (APS). Among the highlights: (1) In the public…

  18. Shelf/fjord exchange driven by coastal-trapped waves in the Arctic

    NASA Astrophysics Data System (ADS)

    Inall, Mark E.; Nilsen, Frank; Cottier, Finlo R.; Daae, Ragnhild

    2015-12-01

    In this article, we show that the class of low frequency (subinertial) waves known as coastal-trapped waves (CTWs) are a significant agent of water volume exchange in a west Svalbard fjord, and by extension more widely along the west Svalbard and east Greenland margins where similar conditions prevail. We show that CTWs generated by weather systems passing across the sloping topography of the shelf break propagate into the fjord, steered by the topography of an across-shelf trough. The CTWs have characteristic periods of ˜2 days, set by the passage time of weather systems. Phase speeds and wavelengths vary seasonally by a factor of two, according to stratification: winter (summer) values are Cp = 0.25 ms-1 (0.5 ms-1) and λ = 40 km (84 km). CTW-induced flow velocities in excess of 0.2 ms-1 at 100 m water depth are recorded. Observationally scaled CTW model results allow their explicit role in volume exchange to be quantified. Of the estimated exchange terms, estuarine exchange is weakest (Qest=0.62×103 m3s-1), followed by barotropic tidal pumping (Qbt=2.5×103 m3s-1), with intermediary exchange dominating (Qi=2.4×104 m3s-1). Oscillatory flows display greatest activity in the 1-5 day period band, and CTW activity is identified as the likely source of variability in the 40-60 h period band. Within that band, intermediary exchange driven by CTWs is estimated as QiCTW_ave=0.82×104 m3s-1; an exchange rate exceeding both barotropic and estuarine exchange estimates.

  19. Uranium biogeochemistry across the redox transition zone of a permanently stratified fjord: Framvaren, Norway

    USGS Publications Warehouse

    Swarzenski, P.W.; McKee, B.A.; Skei, J.M.; Todd, J.F.

    1999-01-01

    During August 1995, the vertical concentration profile of dissolved and particulate uranium exhibited strong non-conservative characteristics in the upper 30 m of Framvaren Fjord. There was a pronounced peak in both particulate (> 0.2 ??m; 1.09 nM) and dissolved (< 0.2 ??m; 17.06 nM) uranium in the finely stratified waters at the O2/H2S interface which is positioned well within the euphotic zone at about 20-21 m. Such concentration maxima at the redox boundary are also observed for dissolved organic carbon (DEC), Sr and Ba. Dissolved U levels seen in the water column from 18 m down to 30 m exceeded the high salinity (salinity = 35) U concentrations (13.63 ?? 0.84 nM; Chen, J.H., Edwards, R.L., Wasserburg, G.L., 1986. 238U, 234U and 232Th in seawater. Earth Planet Sci. Lett. 80, 241-251.) observed uniformly in the open ocean. A prolific population of S microbes (e.g., Chromatium, Chlorobium sp.) flourishes at the O2/H2S interface. The source of elevated U at the redox boundary must be due to microbial uptake and subsequent release processes rather than dilution from oceanic uranium. Uranium oxidation state determinations in waters from 1, 22 and 30 m depth reveal that reduced U(IV) is not present in significant abundance, and that the chemical and/or biological reduction of hexavalent uranium is largely inhibited. Our results suggest that U and other trace constituents such as DOC, Sr, Ba, Fe(II), Mn(II) are greatly modified by direct and indirect microbial transformation reactions which are most concentrated across the redox transition zone in Framvaren Fjord.

  20. Inorganic carbon in a high latitude estuary-fjord system in Canada's eastern Arctic

    NASA Astrophysics Data System (ADS)

    Turk, D.; Bedard, J. M.; Burt, W. J.; Vagle, S.; Thomas, H.; Azetsu-Scott, K.; McGillis, W. R.; Iverson, S. J.; Wallace, D. W. R.

    2016-09-01

    Rapidly changing conditions in the Arctic can have a significant impact on biogeochemical cycles and can be particularly important in high latitude estuary-fjord systems with abundant and diverse freshwater sources. This study provides a first look into the inorganic carbon system and its relation to freshwater sources in Cumberland Sound in the east coast of Baffin Island, Nunavut, Canada. These data contribute to the very limited set of inorganic carbon measurements in high latitude estuary-fjord systems. During the ice-free conditions in August 2011, the meteoric freshwater fractions (MW) in the upper 40 m ranged from 11 to 21% and no sea ice melt (SIM) was present in the Sound. Surface waters were undersaturated with pCO2 (260 and 300 μatm), and DIC and TA ranged between 1779 and 1966 μmol DIC kg-1, and 1922 and 2140 μmol TA kg-1, respectively. Aragonite saturation (ΩAr) state ranged from 1.9 in the surface to 1.4 in the subsurface waters. Data show decreasing TA and ΩAr with increasing MW fraction and suggest that Cumberland Sound waters would become aragonite undersaturated (ΩAr < 1) at MW = 0.37 (95% CI: 0.29 to 0.56). Estimated local δ18O (-19.2‰) and TA (174 μmol TA kg-1) end-members indicate MW was most likely a mixture of river water and glacial melt. In August 2012, MW fractions at the surface were between 8 and 11.5%, and SIM between 7 and 23%. Significant interannual variability of summertime SIM could potentially result in ΩAr undersaturation.

  1. Distribution and spawning dynamics of capelin (Mallotus villosus) in Glacier Bay, Alaska: A cold water refugium

    USGS Publications Warehouse

    Arimitsu, M.L.; Piatt, J.F.; Litzow, M.A.; Abookire, A.A.; Romano, Marc D.; Robards, M.D.

    2008-01-01

    Pacific capelin (Mallotus villosus) populations declined dramatically in the Northeastern Pacific following ocean warming after the regime shift of 1977, but little is known about the cause of the decline or the functional relationships between capelin and their environment. We assessed the distribution and abundance of spawning, non-spawning adult and larval capelin in Glacier Bay, an estuarine fjord system in southeastern Alaska. We used principal components analysis to analyze midwater trawl and beach seine data collected between 1999 and 2004 with respect to oceanographic data and other measures of physical habitat including proximity to tidewater glaciers and potential spawning habitat. Both spawning and non-spawning adult Pacific capelin were more likely to occur in areas closest to tidewater glaciers, and those areas were distinguished by lower temperature, higher turbidity, higher dissolved oxygen and lower chlorophyll a levels when compared with other areas of the bay. The distribution of larval Pacific capelin was not sensitive to glacial influence. Pre-spawning females collected farther from tidewater glaciers were at a lower maturity state than those sampled closer to tidewater glaciers, and the geographic variation in the onset of spawning is likely the result of differences in the marine habitat among sub-areas of Glacier Bay. Proximity to cold water in Glacier Bay may have provided a refuge for capelin during the recent warm years in the Gulf of Alaska.

  2. Temporal and spatial distribution of floating objects in coastal waters of central-southern Chile and Patagonian fjords

    NASA Astrophysics Data System (ADS)

    Hinojosa, Iván A.; Rivadeneira, Marcelo M.; Thiel, Martin

    2011-03-01

    Floating objects are suggested to be the principal vector for the transport and dispersal of marine invertebrates with direct development as well as catalysts for carbon and nutrient recycling in accumulation areas. The first step in identifying the ecological relevance of floating objects in a specific area is to identify their spatio-temporal distribution. We evaluated the composition, abundance, distribution, and temporal variability of floating objects along the continental coast of central-southern Chile (33-42°S) and the Patagonian fjords (42-50°S) using ship surveys conducted in austral winter (July/August) and spring (November) of the years 2002-2005 and 2008. Potential sources of floating items were identified with the aid of publicly available databases and scientific reports. We found three main types of floating objects, namely floating marine debris (mainly plastic objects and Styrofoam), wood (trunks and branches), and floating kelps ( Macrocystis pyrifera and Durvillaea antarctica). Floating marine debris were abundant along most of the examined transects, with markedly lower abundances toward the southern fjord areas. Floating marine debris abundances generally corresponded to the distribution of human activities, and were highest in the Interior Sea of Chiloé, where aquaculture activities are intense. Floating wood appeared sporadically in the study area, often close to the main rivers. In accordance with seasonal river run-off, wood was more abundant along the continental coast in winter (rainy season) and in the Patagonian fjords during the spring surveys (snow melt). Densities of the two floating kelp species were similar along the continental coast, without a clear seasonal pattern. M. pyrifera densities increased towards the south, peaking in the Patagonian fjords, where it was dominant over D. antarctica. Densities of M. pyrifera in the Patagonian fjords were highest in spring. Correlation analyses between the abundances of floating

  3. Modeling the impact of glacial runoff on fjord circulation and submarine melt rate using a new subgrid-scale parameterization for glacial plumes

    NASA Astrophysics Data System (ADS)

    Cowton, Tom; Slater, Donald; Sole, Andrew; Goldberg, Dan; Nienow, Peter

    2015-02-01

    The injection at depth of ice sheet runoff into fjords may be an important control on the frontal melt rate of tidewater glaciers. 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) time scales. We find that for an idealized 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. Although submarine melt rates increase with runoff due to higher melt rates where the plume is in contact with the ice front, we find 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.

  4. Metamorphic facies map of Alaska

    SciTech Connect

    Dusel-Bacon, C.; O-Rourke, E.F.; Reading, K.E.; Fitch, M.R.; Klute, M.A.

    1985-04-01

    A metamorphic-facies of Alaska has been compiled, following the facies-determination scheme of the Working Group for the Cartography of the Metamorphic Belts of the World. Regionally metamorphosed rocks are divided into facies series where P/T gradients are known and into facies groups where only T is known. Metamorphic rock units also are defined by known or bracketed age(s) of metamorphism. Five regional maps have been prepared at a scale of 1:1,000,000; these maps will provide the basis for a final colored version of the map at a scale of 1:2,500,000. The maps are being prepared by the US Geological Survey in cooperation with the Alaska Division of Geological and Geophysical Surveys. Precambrian metamorphism has been documented on the Seward Peninsula, in the Baird Mountains and the northeastern Kuskokwim Mountains, and in southwestern Alaska. Pre-Ordovician metamorphism affected the rocks in central Alaska and on southern Prince of Wales Island. Mid-Paleozoic metamorphism probably affected the rocks in east-central Alaska. Most of the metamorphic belts in Alaska developed during Mesozoic or early Tertiary time in conjuction with accretion of many terranes. Examples are Jurassic metamorphism in east-central Alaska, Early Cretaceous metamorphism in the southern Brooks Range and along the rim of the Yukon-Kovyukuk basin, and late Cretaceous to early Tertiary metamorphism in the central Alaska Range. Regional thermal metamorphism was associated with multiple episodes of Cretaceous plutonism in southeastern Alaska and with early Tertiary plutonism in the Chugach Mountains. Where possible, metamorphism is related to tectonism. Meeting participants are encouraged to comment on the present version of the metamorphic facies map.

  5. The response of the calving front of Helheim Glacier to significant warming of fjord waters, 2009-2010 (Invited)

    NASA Astrophysics Data System (ADS)

    Murray, T.; Luckman, A. J.; Scharrer, K.; Cottier, F.; Bevan, S. L.; Dye, S.; Goldsack, A.; Hughes, A. L.; James, T. D.; Selmes, N.; Valdimarsson, H.

    2010-12-01

    The region of greatest mass loss from the Greenland Ice Sheet is the south-east, where iceberg calving from marine-terminating outlet glaciers dominates mass loss. Helheim Glacier is the third largest catchment of the Greenland Ice Sheet and discharges into Sermilik Fjord on the SE coast, a 90 km long fjord up to 900 m deep. During July 2009 and 2010, we repeated a 60 km profile along Sermilik Fjord measuring water temperature and salinity. The results show warming of up to 4°C of the fjord waters. We report on this interannual variability of fjord waters, adding results from the same profile to be collected in September 2010, and investigate the origin of these warmer waters and their impact on the calving rate and flow dynamics of Helheim Glacier. In July 2009, the fjord waters were strongly stratified, with an upper cold and relatively fresh layer of 150-180 m of water colder than 0°C, below which was warmer (up to 4°C), more saline Subtropical Water (STW) (>34 p.s.u.) originating from the Irminger Current. In July 2010, the upper layer was significantly warmer and saltier, with maximum differences of ~3.2-4°C concentrated at depths between 85-125 m, probably reflecting the influx of new STW. Waters deeper than ~460 m were also warmer by ~1°C. There was some cooling of waters at depths between 180-460 m between the two profiles, but the maximum cooling is 0.3°C, and typically the cooling at this depth is 0-0.2°C. Overall the results suggest a significant increase in the heat available for melting at the glacier front margin. We would therefore expect increased underwater melting, and hence enhanced calving and ice flow rates. During 2009, Helheim Glacier retreated and advanced repeatedly ~1.2 km, ending the year some 0.75 km retreated overall. In 2010, the glacier has retreated 1.3 km to 20 August: in the same period in 2009 it had retreated 0.8-1.0 km. Ice flow rates close to the margin from tracking optical and SAR imagery varied from 18-24 m/d in 2009

  6. New cosmogenic exposure dates from Sermilik Fjord, southeast Greenland document rapid early Holocene retreat of Helheim Glacier

    NASA Astrophysics Data System (ADS)

    Hughes, A. L.; Rainsley, E.; Murray, T.; Fogwill, C. J.

    2010-12-01

    Marine-terminating glaciers are currently the dominant route for mass loss from the Greenland Ice Sheet (GrIS). Over the last decade Helheim Glacier, in concert with the majority of marine-terminating glaciers of the southeast sector of the GrIS, has exhibited dramatic changes in speed, thinning and retreat rates. The Holocene retreat history of the outlet glaciers of southeast Greenland is, however, largely unconstrained. Without detailed records of retreat over longer-time scales recent changes cannot be placed in context, nor is there sufficient evidence to constrain ice sheet models for improved estimates of future sea level rise. We present the first direct chronological constraint on the retreat of ice from Sermilik Fjord in southeast Greenland, the former drainage route of Helheim Glacier. Samples spanning the full length of the 80 km fjord were collected from erratics and streamlined bedrock in July 2009-10 and analysed for terrestrial cosmogenic nuclide (10Be) dating. Overlapping exposure ages indicate rapid evacuation of ice from much of the fjord at around 10.5 ka BP. Such substantial early Holocene retreat coincides with establishment of the local marine limit at c. 11 ka BP (Long et al. 2008). The new dates extend and confirm results from a tributary valley close to the fjord mouth that placed retreat from the present day coastline at c. 11.5 ka (Roberts et al. 2008). References: Roberts, D.H., Long, A.J., Schnabel, C., Freeman, S. and Simpson, M.J.R. 2008. The deglacial history of southeast sector of the Greenland Ice Sheet during the Last Glacial Maximum. Quaternary Science Reviews, 27, 1505-1516. Long, A.J., Roberts, R.H., Simpson, M.J.R., Dawson, S., Milne, G.A. and Huybrechts, P. 2008. Late Weichselian relative sea-level changes and ice sheet history in southeast Greenland. Earth and Planetary Science Letters, 272, 8-18.

  7. Water from land - fresh water outflow from glaciated and non-glaciated catchments into the Hornsund fjord, Svalbard

    NASA Astrophysics Data System (ADS)

    Nawrot, Adam; Wawrzyniak, Tomasz; Walczowski, Waldemar; Osuch, Marzena

    2016-04-01

    Freshwater processes in South Spitsbergen catchments are facing climate related alterations and issues, such as prolongation of the ablation seasons, water level changes and droughts. Snow accumulation and duration of snow cover in high latitude areas largely determine hydrological and periglacial processes, influencing flora, fauna and their ecology. Hydrological data from this part of the Arctic so far were sparse and major gaps remained in our understanding of freshwater distribution, regime, status and threats. From 2013 to 2015 as part of multidisciplinary and complex investigations within the framework of "AWAKE2 - Arctic Climate System Study of Ocean, Sea Ice and Glaciers Interactions in Svalbard Area" project, field measurements were conducted around Hornsund, the southernmost fjord of Spitsbergen. This was the first study of the fresh water and snow cover in such scale in this area and included spatial distribution of snow, together with water balance measurements in non-glaciated and glaciated catchments. During the fieldwork in Hornsund Fjord area, snow thickness and snow density have been measured in 350 and 50 points, respectively. Precipitation was measured in 6 points. Runoff was measured on 7 rivers in different glaciated (Ariedalen, Sofiedalen, Lorchbreen, Bautabreen, Gashamna) and non-glaciated (Fuglebekken, Lisbetdalen) catchments. Meteorological observations were conducted at the Hornsund Polish Polar Station and in the in the surroundings of Hornsund fjord. The results of this investigation show response of the freshwater hydrological processes to observed seasonal climatic variations in this area. Approximated water balance and known volume of fresh water outflow to the sea are the key components of understanding Arctic fjord ecosystem mechanisms. This is the first comprehensive investigation of the water balance in this region. Project AWAKE2 is funded by Norway Grants.

  8. Chlorophyll-a thin layers in the Magellan fjord system: The role of the water column stratification

    NASA Astrophysics Data System (ADS)

    Ríos, Francisco; Kilian, Rolf; Mutschke, Erika

    2016-08-01

    Fjord systems represent hotspots of primary productivity and organic carbon burial. However, the factors which control the primary production in mid-latitude fjords are poorly understood. In this context, results from the first fine-scale measurements of bio-oceanographic features in the water column of fjords associated with the Strait of Magellan are presented. A submersible fluorescence probe (FP) was used to measure the Chlorophyll-a (Chl-a) concentration in situ, along with conductivity, temperature, hydrostatic pressure (depth) and dissolved oxygen (CTD-O2) of the water column. The Austral spring results of 14 FP-CTD-O2 profiles were used to define the vertical and horizontal patches of the fluorescent pigment distribution and their spatial relations with respect to the observed hydrographic features. Three zones with distinct water structures were defined. In all zones, the 'brown' spectral group (diatoms and dinoflagellates) predominated accounting for >80 wt% of the phytoplankton community. Thin layers with high Chl-a concentration were detected in 50% of the profiles. These layers harbored a substantial amount (30-65 wt%) of the phytoplankton biomass. Stratification was positively correlated to the occurrence of Chl-a thin layers. In stable and highly stratified water columns the integrated Chl-a concentration was higher and frequently located within thin layers whereas well mixed water columns displayed lower values and more homogeneous vertical distribution of Chl-a. These results indicate that mixing/stability processes are important factors accounting to the vertical distribution of Chl-a in Magellan fjords.

  9. The Saguenay Fjord, Quebec, Canada: Integrating marine geotechnical and geophysical data for spatial seismic slope stability and hazard assessment

    USGS Publications Warehouse

    Urgeles, R.; Locat, J.; Lee, H.J.; Martin, F.

    2002-01-01

    In 1996 a major flood occurred in the Saguenay region, Quebec, Canada, delivering several km3 of sediment to the Saguenay Fjord. Such sediments covered large areas of the, until then, largely contaminated fjord bottom, thus providing a natural capping layer. Recent swath bathymetry data have also shown that sediment landslides are widely present in the upper section of the Saguenay Fjord, and therefore, should a new event occur, it would probably expose the old contaminated sediments. Landslides in the Upper Saguenay Fjord are most probably due to earthquakes given its proximity to the Charlevoix seismic region and to that of the 1988 Saguenay earthquake. In consequence, this study tries to characterize the permanent ground deformations induced by different earthquake scenarios from which shallow sediment landslides could be triggered. The study follows a Newmark analysis in which, firstly, the seismic slope performance is assessed, secondly, the seismic hazard analyzed, and finally an evaluation of the seismic landslide hazard is made. The study is based on slope gradients obtained from EM1000 multibeam bathymetry data as well as water content and undrained shear strength measurements made in box and gravity cores. Ground motions integrating local site conditions were simulated using synthetic time histories. The study assumes the region of the 1988 Saguenay earthquake as the most likely source area for earthquakes capable of inducing large ground motions in the Upper Saguenay region. Accordingly, we have analyzed several shaking intensities to deduce that generalized sediment displacements will begin to occur when moment magnitudes exceed 6. Major displacements, failure, and subsequent landslides could occur only from earthquake moment magnitudes exceeding 6.75. ?? 2002 Elsevier Science B.V. All rights reserved.

  10. Polychlorinated dibenzo-p-dioxins and dibenzofurans in sediments and biota of the Saguenay Fjord and the St. Lawrence Estuary

    SciTech Connect

    Brochu, C.; Moore, S.; Pelletier, E.

    1995-12-31

    Sediment samples and marine organisms were collected in the Saguenay Fjord and at two selected sites of the St. Lawrence Estuary in 1991. Total PCDDs and total PCDFs ranged from 22 to 352 ng kg{sup {minus}1} and 29 to 188 ng kg{sup {minus}1}, respectively in Saguenay sediments, while total PCDFs reached, 287 ng kg{sup {minus}1} in Baie des Anglais, a small and deep bay of the St. Lawrence Estuary impacted by PCBs during the 1970s. All biological samples contained detectable amounts of chlorinated dibenzodioxins and dibenzofurans, apart from the North Atlantic cod (Gadus morhua). The highest concentrations (up to 59.7 ng kg{sup {minus}1} total PCDFs and 2.54 ng kg{sup {minus}1} 2,3,7,8T4CDD Equivalent (TCDD TEQ)) were observed in crab (Chionoecetes opilio) caught in Saguenay Fjord and in crab and whelk (Buccinwn undatwn) collected in Baie des Anglais. Nordic shrimp (Pandalus borealis) is less contaminated with a maximum total PCDDs and PCDFs concentration of 14.0 ng kg{sup {minus}1} and TCDD TEQ never exceeding 0.7 ng kg{sup {minus}1}. Greenland halibut (Reinhardtius hippoglossoides) caught in the Saguenay Fjord contained only 2,3,7,8 substituted congeners in their tissues leading to a low average TCDD TEQ of 1.66 ng kg{sup {minus}1}. Based upon this first series of results, benthic organisms and fish from the Saguenay Fjord and the north shore of the St. Lawrence Estuary are exposed to low levels of PCDDs and PCDFs, and carry tissue concentrations well below international guidelines for fisheries products.

  11. Dynamics of dissolved organic matter in fjord ecosystems: Contributions of terrestrial dissolved organic matter in the deep layer

    NASA Astrophysics Data System (ADS)

    Yamashita, Youhei; McCallister, S. Leigh; Koch, Boris P.; Gonsior, Michael; Jaffé, Rudolf

    2015-06-01

    Annually, rivers and inland water systems deliver a significant amount of terrestrial organic matter (OM) to the adjacent coastal ocean in both particulate and dissolved forms; however, the metabolic and biogeochemical transformations of OM during its seaward transport remains one of the least understood components of the global carbon cycle. This transfer of terrestrial carbon to marine ecosystems is crucial in maintaining trophic dynamics in coastal areas and critical in global carbon cycling. Although coastal regions have been proposed as important sinks for exported terrestrial materials, most of the global carbon cycling data, have not included fjords in their budgets. Here we present distributional patterns on the quantity and quality of dissolved OM in Fiordland National Park, New Zealand. Specifically, we describe carbon dynamics under diverse environmental settings based on dissolved organic carbon (DOC) depth profiles, oxygen concentrations, optical properties (fluorescence) and stable carbon isotopes. We illustrate a distinct change in the character of DOC in deep waters compared to surface and mid-depth waters. Our results suggest that, both, microbial reworking of terrestrially derived plant detritus and subsequent desorption of DOC from its particulate counterpart (as verified in a desorption experiment) are the main sources of the humic-like enriched DOC in the deep basins of the studied fjords. While it has been suggested that short transit times and protection of OM by mineral sorption may ultimately result in significant terrestrial carbon burial and preservation in fjords, our data suggests the existence of an additional source of terrestrial OM in the form of DOC generated in deep, fjord water.

  12. Transport and reaction of heavy metals in Alaskan fjord estuaries. Annual report, July 1, 1980-May 31, 1981

    SciTech Connect

    Burrell, D.C.

    1981-05-01

    The program investigates the potential effects of energy-related chemical pollution in Alaskan fjords. The long-term objective is to understand the chemical, physical, and biological processes responsible for the transport and reaction of heavy metals in these sub-arctic estuaries. The physical circulation and mixing processes, the nature and reactions of terrigenous organics and particulate sediment within the mixing zone, and aspects of the basin sediment oxygen, carbon and nutrient budgets in addition to study of individual metals are investigated. Mainly copper, iron and manganese are being studied since these provide information on physical-chemical processes common to, or greatly affecting, a much wider range of metals. The bulk of the Work completed section of this report refers to Resurrection Bay, a southcentral Alaskan fjord. The Work in progress reported here outlines recent investigations in Boca de Quadra, a southeast Alaskan fjord-estuary. We are here investigating deep and surface water circulation; oxygen, carbon and nutrient budgets; the compositions, reaction and flux of particulate sediment; and organic-heavy metal associations in the freshwater and in the mixing zone.

  13. Transport and sediment accumulation of sup 210 Pb and sup 137 Cs in two southeast Alaskan fjords

    SciTech Connect

    Sugai, S.F. )

    1991-05-01

    Sediment profiles of {sup 210}Pb and {sup 137}Cs in cores collected at increasing distances form the heads of Smeaton Bay and Boca de Quadra fjords indicate that watersheds influence the inventories of radioisotopes present and that the steep topographies of the fjords enhance sediment redistribution. Episodic deposition of terrestrially derived sediment was responsible for roughly 50% of the {sup 137}Cs and 45% of the {sup 210}Pb inventories in shallower (less than 180 m) locations in Wilson and Bakewell arms of Smeaton Bay. {sup 210}Pb sedimentation rates at shallower sites when corrected for episodic deposition were less than sedimentation rates obtained in the deep basins of the fjords where sediment focusing and increased primary productivity in the overlaying water column occur. Higher fluxes of dissolved Mn from surficial sediments and subsequent reoxidation in the overlying water may have enhanced scavenging of {sup 210}Pb in basin locatons resulting in higher inventories. Episodic events have occured frequently in Smeaton Bay and Boca de Quadra suggesting that steady-state conditions with respect to sedimenting particles can be achieved only when averaged over long time periods approaching the time over which {sup 137}Cs and {sup 210}Pb are useful.

  14. Evolution of a trough-fan system: Scoresby Sund fjord, central-east Greenland

    NASA Astrophysics Data System (ADS)

    Pérez, Lara F.; Nielsen, Tove; Knutz, Paul C.; Kuijpers, Antoon; Damm, Volkmar

    2016-04-01

    The continental shelf along the east margin of Greenland is shaped by several, glacially carved transverse troughs that constitute the oceanward extension of the major fjords. Scoresby Sund is the most prominent fjord of central-east Greenland and separates Liverpool Land, to the north, from Blosseville Kyst to the south. Offshore of Scoresby Sund a large glacial trough mouth fan (TMF) has been built through successive phases of glacial advances. Morpho-structural and seismo-stratigraphic analyses of the Scoresby Sund TMF have been done using all Multichannel Seismic (MCS) profiles available in the area. The ODP site 987 of the leg 162 is located in the abyssal plain offshore of Scoresby Sund and was used for age estimations. The width of the continental shelf in the study area ranges from a 65 km narrow part along the Blosseville Kyst to 120 km off Scoresby Sund. The average water depth is shallower than 300 m, deepening to 600 m along Scoresby Sund glacial trough. Oceanwards a steep slope, seafloor falls into the 2250 m deep abyssal plain of the south Greenland Sea. The sedimentary cover displays maximum thickness along the middle continental shelf (2.8 s TWTT on average). Seven major stratigraphic discontinuities could be identified within the sedimentary record. They restrict eight major seismic units, named from 8 to 1, in upward stratigraphic order. The distribution and seismic facies of these units reveal the evolutionary sequence of the study area from early Cenozoic to Present. The lowest unit, Unit 8, is post-basalt to middle-late Miocene age and represents a pre-glacial depositional stage when tectonic events controlled the sedimentation. Deposition of Unit 7 occurred by late Miocene, revealing glacial-related deposits and ice-stream along Scoresby Sund fjord. Unit 6 was formed during early Pliocene by glacial advance over the continental shelf leading to strong erosive surfaces in the shelf area and Mass Transport Deposits (MTDs) in the northern abyssal

  15. Alaska Interagency Ecosystem Health Work Group

    USGS Publications Warehouse

    Shasby, Mark

    2009-01-01

    The Alaska Interagency Ecosystem Health Work Group is a community of practice that recognizes the interconnections between the health of ecosystems, wildlife, and humans and meets to facilitate the exchange of ideas, data, and research opportunities. Membership includes the Alaska Native Tribal Health Consortium, U.S. Geological Survey, Alaska Department of Environmental Conservation, Alaska Department of Health and Social Services, Centers for Disease Control and Prevention, U.S. Fish and Wildlife Service, Alaska Sea Life Center, U.S. Environmental Protection Agency, and Alaska Department of Fish and Game.

  16. First observations of jelly-falls at the seafloor in a deep-sea fjord

    NASA Astrophysics Data System (ADS)

    Sweetman, Andrew K.; Chapman, Annelise

    2011-12-01

    Faunal communities at the deep-sea floor mainly rely on the downward transport of particulate organic material for energy, which can come in many forms, ranging from phytodetritus to whale carcasses. Recently, studies have shown that the deep-sea floor may also be subsidized by fluxes of gelatinous material to the benthos. The deep-sea scyphozoan medusa Periphylla periphylla is common in many deep-sea fjords in Norway and recent investigations in Lurefjorden in western Norway suggest that the biomass of this jellyfish currently exceeds 50000 t here. To quantify the presence of dead P. periphylla jellyfish falls (hereafter termed jelly-falls) at the deep seafloor and the standing stock of carbon (C) and nitrogen (N) deposited on the seafloor by this species, we made photographic transects of the seafloor, using a 'Yo-Yo' camera system during an opportunistic sampling campaign in March 2011. Of 218 seafloor photographs taken, jelly-falls were present in five, which resulted in a total jelly-fall abundance of 1×10 -2 jelly-falls m -2 over the entire area surveyed. Summed over the entire area of seafloor photographed, 1×10 -2 jelly-falls m -2 was equivalent to a C- and N-biomass of 13 mg C m -2 and 2 mg N m -2. The contribution of each jelly-fall to the C- and N-amount of the sediment in the immediate vicinity of each fall (i.e. to sediment in each 3.02 m 2 image in which jelly-falls were observed) was estimated to be 568±84 mg C m -2 and 88±13 mg N m -2. The only megafaunal taxon observed around or on top of the jelly-falls was caridean shrimp (14±5 individuals jelly-fall -1), and shrimp abundance was significantly greater in photographs in which a jelly-fall was found (14±5 individuals image -1) compared to photographs in which no jelly-falls were observed (1.4±0.7 individuals image -1). These observations indicate that jelly-falls in this fjord can enhance the sedimentary C- and N-amount at the deep-sea floor and may provide nutrition to benthic and demersal

  17. North Atlantic Oscillation Dynamics Recorded in Central Norwegian Fjord Sediments During the Past 2800 Years

    NASA Astrophysics Data System (ADS)

    Faust, J.; Knies, J.; Fabian, K.; Giraudeau, J.

    2014-12-01

    The North Atlantic Oscillation (NAO) is the leading mode of atmospheric circulation variability in the North Atlantic region. Long-term NAO reconstructions are crucial to better understand NAO variability in its response to climate forcing factors, and assess predictability and possible shifts associated with ongoing global warming. However, existing records are rare and often inconsistent (Pinto and Raible, 2012). Fjord deposits have a great potential for providing high-resolution sedimentary records that reflect local terrestrial and marine processes and, therefore, offer unique opportunities for the investigation of sedimentological and geochemical climatically induced processes. Recently, Faust et al. (2014) provided a comprehensive overview of the Trondheimsfjord environmental system by applying a geochemical multiproxy analysis on surface sediment samples and compared his findings with available geochemical data from the fjords drainage area. Here we use the gained knowledge to establish the first high resolution NAO proxy record from marine sediments. By comparing geochemical measurements from a short sediment core with instrumental data we show that marine primary productivity proxies are sensitive to NAO changes during the past 50 years. This result is used to link a 2,800 years paleoproductivity record to a 500-year long winter NAO reconstruction based on early instrumental and documentary proxy data. We find that NAO variabilities coincide with climatically associated paleo-demographic trends and persistent positive/negative NAO phases are in accordance with cooler/warmer climate periods, such as Medieval Climate Anomaly and Little Ice Age. Moreover, negative NAO phases coincide with northern hemisphere glacier advances and rapid phase transitions related to large volcanic eruptions indicate the existence of internal atmospheric thresholds and instabilities in the atmospheric circulation pattern. Faust J.C., Knies J., Slagstad T., Vogt C., Milzer G. and

  18. Alaska Athabascan stellar astronomy

    NASA Astrophysics Data System (ADS)

    Cannon, Christopher M.

    Stellar astronomy is a fundamental component of Alaska Athabascan cultures that facilitates time-reckoning, navigation, weather forecasting, and cosmology. Evidence from the linguistic record suggests that a group of stars corresponding to the Big Dipper is the only widely attested constellation across the Northern Athabascan languages. However, instruction from expert Athabascan consultants shows that the correlation of these names with the Big Dipper is only partial. In Alaska Gwich'in, Ahtna, and Upper Tanana languages the Big Dipper is identified as one part of a much larger circumpolar humanoid constellation that spans more than 133 degrees across the sky. The Big Dipper is identified as a tail, while the other remaining asterisms within the humanoid constellation are named using other body part terms. The concept of a whole-sky humanoid constellation provides a single unifying system for mapping the night sky, and the reliance on body-part metaphors renders the system highly mnemonic. By recognizing one part of the constellation the stargazer is immediately able to identify the remaining parts based on an existing mental map of the human body. The circumpolar position of a whole-sky constellation yields a highly functional system that facilitates both navigation and time-reckoning in the subarctic. Northern Athabascan astronomy is not only much richer than previously described; it also provides evidence for a completely novel and previously undocumented way of conceptualizing the sky---one that is unique to the subarctic and uniquely adapted to northern cultures. The concept of a large humanoid constellation may be widespread across the entire subarctic and have great antiquity. In addition, the use of cognate body part terms describing asterisms within humanoid constellations is similarly found in Navajo, suggesting a common ancestor from which Northern and Southern Athabascan stellar naming strategies derived.

  19. Operation IceBridge Alaska

    NASA Astrophysics Data System (ADS)

    Larsen, C.

    2015-12-01

    The University of Alaska Fairbanks (UAF) has flown LiDAR missions for Operation IceBridge in Alaska each year since 2009, expanding upon UAF's airborne laser altimetry program which started in 1994. These observations show that Alaska's regional mass balance is -75+11/-16 Gt yr-1 (1994-2013) (Larsen et al., 2015). A surprising result is that the rate of surface mass loss observed on non-tidewater glaciers in Alaska is extremely high. At these rates, Alaska contributes ~1 mm to global sea level rise every 5 years. Given the present lack of adequate satellite resources, Operation IceBridge airborne surveys by UAF are the most effective and efficient method to monitor this region's impact on global sea level rise. Ice depth measurements using radar sounding have been part of these airborne surveys since 2012. Many of Alaska's tidewater glaciers are bedded significantly below sea level. The depth and extent of glacier beds below sea level are critical factors in the dynamics of tidewater retreat. Improved radar processing tools are being used to predict clutter using forward simulation. This is essential to properly sort out true bed returns, which are often masked or obscured by valley wall returns. This presentation will provide an overview of the program, highlighting recent findings and observations from the most recent campaigns, and focusing on techniques used for the extrapolation of surface elevation changes to regional mass balances.

  20. Seasonal surface layer dynamics and sensitivity to runoff in a high Arctic fjord (Young Sound/Tyrolerfjord, 74°N)

    NASA Astrophysics Data System (ADS)

    Bendtsen, Jørgen; Mortensen, John; Rysgaard, Søren

    2014-09-01

    Runoff from the Greenland Ice Sheet, local glaciers, and snowmelt along the northeastern Greenland coastline has a significant impact on coastal water masses flowing south toward Denmark Strait. Very few direct measurements of runoff currently exist in this large area, and the water masses near the coast are also difficult to measure due to the presence of icebergs and sea ice. Measurements from the Zackenberg Research station, located in Young Sound/Tyrolerfjord in northeast Greenland (74°N), provide some of the few observations of hydrographic, hydrologic, and atmospheric parameters from this remote area. Here we analyze measurements from the fjord and also measurements in the ambient water masses, which are found in the outer fjord and between the fjord and the East Greenland Current and validate and apply a numerical model of the fjord. A model sensitivity study allows us to constrain runoff estimates for the area. We also show that a total runoff between 0.9 and 1.4 km3 in 2006 is in accordance with observed surface salinities and calculated freshwater content in the fjord. This indicates that earlier reported runoff to the area is significantly underestimated and that melt from glaciers and the Greenland Ice Sheet in this region may be up to 50% larger than the current estimate. Model simulations indicate the presence of a cold low-saline coastal water mass formed by runoff from fjords north of the Young Sound/Tyrolerfjord system. Simulations of passive and age tracers show that residence time of river water during the summer period is about 1 month in the inner part of the fjord. This article was corrected on 10 OCT 2014. See the end of the full text for details.

  1. Abundance of ringed seals (Pusa hispida) in the fjords of Spitsbergen, Svalbard, during the peak molting period

    USGS Publications Warehouse

    Krafft, B.A.; Kovacs, K.M.; Andersen, M.; Aars, J.; Lydersen, C.; Ergon, T.; Haug, T.

    2006-01-01

    Ringed seal (Pusa hispida) abundance in Spitsbergen, Svalbard, was estimated during the peak molting period via aerial, digital photographic surveys. A total of 9,145 images, covering 41.7%?100% of the total fast-ice cover (1,496 km2) of 18 different fjords and bays, were inspected for the presence of ringed seals. A total of 1,708 seals were counted, and when accounting for ice areas that were not covered by images, a total of 3,254 (95% CI: 3,071?3,449) ringed seals were estimated to be hauled out during the surveys. Extensive behavioral data from radio-tagged ringed seals (collected in a companion study) from one of the highest density fjords during the molting period were used to create a model that predicts the proportion of seals hauled out on any given date, time of day, and under various meteorological conditions. Applying this model to the count data from each fjord, we estimated that a total of 7,585 (95% CI: 6,332-9,085) ringed seals were present in the surveyed area during the peak molting period. Data on interannual variability in ringed seal abundance suggested higher numbers of seals in Van Keulenfjorden in 2002 compared to 2003, while other fjords with very stable ice cover showed no statistical differences. Poor ice conditions in general in 2002 probably resulted in seals from a wide area coming to Van Keulenfjorden (a large fjord with stable ice in 2002). The total estimated number of ringed seals present in the study area at the time of the survey must be regarded as a population index, or at least a minimum estimate for the area, because it does not account for individuals leaving and arriving, which might account for a considerable number of animals. The same situation is likely the case for many other studies reporting aerial census data for ringed seals. To achieve accurate estimates of population sizes from aerial surveys, more extensive knowledge of ringed seal behavior will be required.

  2. Effects of the Alaska earthquake of March 27, 1964, on shore processes and beach morphology: Chapter J in The Alaska earthquake, March 27, 1964: regional effects

    USGS Publications Warehouse

    Stanley, Kirk W.

    1968-01-01

    Some 10,000 miles of shoreline in south-central Alaska was affected by the subsidence or uplift associated with the great Alaska earthquake of March 27, 1964. The changes in shoreline processes and beach morphology that were suddenly initiated by the earthquake were similar to those ordinarily caused by gradual changes in sea level operating over hundreds of years, while other more readily visible changes were similar to some of the effects of great but short-lived storms. Phenomena became available for observation within a few hours which would otherwise not have been available for many years. In the subsided areas—including the shorelines of the Kenai Peninsula, Kodiak Island, and Cook Inlet—beaches tended to flatten in gradient and to recede shoreward. Minor beach features were altered or destroyed on submergence but began to reappear and to stabilize in their normal shapes within a few months after the earthquake. Frontal beach ridges migrated shoreward and grew higher and wider than they were before. Along narrow beaches backed by bluffs, the relatively higher sea level led to vigorous erosion of the bluff toes. Stream mouths were drowned and some were altered by seismic sea waves, but they adjusted within a few months to the new conditions. In the uplifted areas, generally around Prince William Sound, virtually all beaches were stranded out of reach of the sea. New beaches are gradually developing to fit new sea levels, but the processes are slow, in part because the material on the lower parts of the old beaches is predominantly fine grained. Streams were lengthened in the emergent areas, and down cutting and bank erosion have increased. Except at Homer and a few small villages, where groins, bulkheads, and cobble-filled baskets were installed, there has been little attempt to protect the postearthquake shorelines. The few structures that were built have been only partially successful because there was too little time to study the habits of the new shore

  3. Improving Student Achievement in Alaska. Alaska Goals 2000 Annual Report, 1997-98.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau.

    Alaska Goals 2000 is part of a coordinated, statewide effort to improve public education for all students in Alaska. In 1997-1998, 90% of Alaska's federal funding was used to fund grants to local school districts, and 10% was used to fund state-level activities through the Alaska Department of Education. During 1997-1998, curriculum frameworks and…

  4. 78 FR 73144 - Subsistence Management Program for Public Lands in Alaska; Western Interior Alaska Federal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-05

    ... Subsistence Management Program for Public Lands in Alaska; Western Interior Alaska Federal Subsistence... subsistence uses on Federal public lands and waters in Alaska. The Federal Subsistence Board, which includes... the subsistence management of fish and wildlife on Federal public lands in Alaska. The Board...

  5. Alaska's Children, 1998. Alaska Head Start State Collaboration Project, Quarterly Report.

    ERIC Educational Resources Information Center

    Douglas, Dorothy, Ed.

    1998-01-01

    This document consists of four issues of the quarterly report "Alaska's Children," which provides information on the Alaska Head Start State Collaboration Project and updates on Head Start activities in Alaska. Regular features in the issues include a calendar of conferences and meetings, a status report on Alaska's children, reports from the…

  6. In-Situ Observations of a Subglacial Outflow Plume in a Greenland Fjord

    NASA Astrophysics Data System (ADS)

    Mankoff, K. D.; Straneo, F.; Singh, H.; Das, S. B.

    2014-12-01

    We present oceanographic observations collected in and immediately outside of a buoyant, fresh, sediment-laden subglacial outflow plume rising up the marine-terminating front of Sarqardleq Glacier, Greenland (68.9 N, 50.4 W). Subglacial outflow plumes, associated with the discharge at depth of upstream glacial surface melt, entrain the relatively warm fjord waters and are correlated with enhanced submarine melt and increased calving. Few in-situ observations exist due to the challenges of making measurements at the calving front of glaciers. Our data were collected using a small boat, a helicopter, and a JetYak (a remote-controlled jet-ski-powered kayak). Temperature and salinity profiles in, around, and far from the plume are used to described its oceanographic properties, spatial extent, and temporal variability. This plume rises vertically up the ice front expanding laterally and away from the ice, over-shoots its stable isopycnal and reaches the surface. Its surface expression is identified by colder, saltier, sediment-laden water flowing at ~5 m/s away from the ice face. Within ~300 m from the ice it submerges as it seeks buoyant stability.

  7. Structure of marine predator and prey communities along environmental gradients in a glaciated fjord

    USGS Publications Warehouse

    Renner, Martin; Arimitsu, Mayumi L.; Piatt, John F.

    2012-01-01

    Spatial patterns of marine predator communities are influenced to varying degrees by prey distribution and environmental gradients. We examined physical and biological attributes of an estuarine fjord with strong glacier influence to determine the factors that most influence the structure of predator and prey communities. Our results suggest that some species, such as walleye pollock (Theragra chalcogramma), black-legged kittiwake (Rissa tridactyla), and glaucous-winged gull (Larus glaucescens), were widely distributed across environmental gradients, indicating less specialization, whereas species such as capelin (Mallotus villosus), harbor seal (Phoca vitulina), and Kittlitz's murrelet (Brachyramphus brevirostris) appeared to have more specialized habitat requirements related to glacial influence. We found that upper trophic level communities were well correlated with their mid trophic level prey community, but strong physical gradients in photic depth, temperature, and nutrients played an important role in community structure as well. Mid-trophic level forage fish communities were correlated with the physical gradients more closely than upper trophic levels were, and they showed strong affinity to tidewater glaciers. Silica was closely correlated with the distribution of fish communities, the mechanisms of which deserve further study.

  8. Modelling subglacial discharge and its influence on ocean heat transport in Arctic fjords

    NASA Astrophysics Data System (ADS)

    Bendtsen, Jørgen; Mortensen, John; Rysgaard, Søren

    2015-11-01

    Tidewater outlet glaciers are directly connected to the ocean via ice walls or floating shelves. Melting and freezing of ice, runoff, englacial, and subglacial discharge of freshwater and ocean heat transport are therefore potential feedback processes between glacial ice flow and ocean circulation. Subglacial discharge occurs at the base of tidewater glacier outlets where out-flowing freshwater forms a convective buoyant plume ascending close to the glacier face and, due to entrainment, transports relatively warm and saline ambient bottom water up towards the surface. Plume dynamics, typically occurring at sub-grid scales in regional ocean models, therefore has to be parameterized in areas where ice-ocean interactions occur, as for example in Arctic fjords. Here, we develop and analyze a new simple boundary condition of subglacial discharge where entrainment-induced transport between the subsurface and surface layer is described. A sensitivity study showed that subglacial discharge increased ocean heat transport near the glacier whereas the impact from plume-entrainment became relatively small further from the glacier. Subglacial discharge was shown to have a significant influence on surface concentrations. The impact from subglacial discharge was demonstrated in a regional model of Godthåbsfjord (64°N), located at the west coast of Greenland, where surface concentrations near the glacier were shown to be sensitive to subglacial discharge in accordance with observations.

  9. Distribution, abundance, and habitat associations of a large bivalve (Panopea generosa) in a eutrophic, fjord estuary

    USGS Publications Warehouse

    Mcdonald, P. Sean; Essington, Timothy E.; Davis, Jonathan P.; Galloway, Aaron W.E.; Stevick, Bethany C.; Jensen, Gregory C.; Vanblaricom, Glenn R.; Armstrong, David A.

    2015-01-01

    Marine bivalves are important ecosystem constituents and frequently support valuable fisheries. In many nearshore areas, human disturbance—including declining habitat and water quality—can affect the distribution and abundance of bivalve populations, and complicate ecosystem and fishery management assessments. Infaunal bivalves, in particular, are frequently cryptic and difficult to detect; thus, assessing potential impacts on their populations requires suitable, scalable methods for estimating abundance and distribution. In this study, population size of a common benthic bivalve (the geoduck Panopea generosa) is estimated with a Bayesian habitat-based model fit to scuba and tethered camera data in Hood Canal, a fjord basin in Washington state. Densities declined more than two orders of magnitude along a north—south gradient, concomitant with patterns of deepwater dissolved oxygen, and intensity and duration of seasonal hypoxia. Across the basin, geoducks were most abundant in loose, unconsolidated, sand substrate. The current study demonstrates the utility of using scuba, tethered video, and habitat models to estimate the abundance and distribution of a large infaunal bivalve at a regional (385-km2) scale.

  10. Norwegian fjord sediments reveal NAO related winter temperature and precipitation changes of the past 2800 years

    NASA Astrophysics Data System (ADS)

    Faust, Johan; Fabian, Karl; Giraudeau, Jacques; Knies, Jochen

    2016-04-01

    The North Atlantic Oscillation (NAO) is the leading mode of atmospheric circulation variability in the North Atlantic region. Associated shifts of storm tracks, precipitation and temperature patterns affect energy supply and demand, fisheries and agricultural, as well as marine and terrestrial ecological dynamics. Long-term NAO reconstructions are crucial to better understand NAO variability in its response to climate forcing factors, and assess predictability and possible shifts associated with ongoing climate change. Fjord deposits have a great potential for providing high-resolution sedimentary records that reflect local terrestrial and marine processes and, therefore, offer unique opportunities for the investigation of sedimentological and geochemical climatically induced processes. A recent study of instrumental time series revealed NAO as main factor for a strong relation between winter temperature, precipitation and river discharge in central Norway over the past 50 years. Here we use the gained knowledge to establish the first high resolution NAO proxy record from marine sediments. By comparing geochemical measurements from a short sediment core with instrumental data we show that marine primary productivity proxies are sensitive to NAO changes. Conditioned on a stationary relation between our climate proxy and the NAO we establish the first high resolution NAO proxy record (NAO-TFJ) from marine sediments covering the past 2,800 years. The NAO-TFJ shows distinct co-variability with climate changes over Greenland, solar activity and Northern Hemisphere glacier dynamics as well as climatically associated paleo-demographic trends.

  11. Floating marine debris in fjords, gulfs and channels of southern Chile.

    PubMed

    Hinojosa, Iván A; Thiel, Martin

    2009-08-01

    Floating marine debris (FMD) is reported from all oceans. The bulk of FMD are plastics, which due to their longevity cause multiple negative impacts on wildlife and environment. Identifying the origins of FMD (land- or sea-based) is important to take the necessary steps to diminish their abundance. Using ship surveys we examined the abundance, composition and distribution of FMD during the years 2002-2005 in the fjords, gulfs and channels of southern Chile. Abundances of FMD were relatively high compared with other studies, ranging from 1 to 250 items km(-2). The majority (approximately 80%) of FMD was composed of styrofoam (expanded polystyrene), plastic bags and plastic fragments. Styrofoam, which is intensively used as flotation device by mussel farms, was very abundant in the northern region but rarely occurred in the southern region of the study area. Food sacks from salmon farms were also most common in the northern region, where approximately 85% of the total Chilean mussel and salmon harvest is produced. Plastic bags, which could be from land- or sea-based sources, were found throughout the entire study area. Our results indicate that sea-based activities (mussel farming and salmon aquaculture) are responsible for most FMD in the study area. In order to reduce FMDs in the environment, in addition to stronger legislation and identification of potential sources, we suggest environmental education programs and we encourage public participation (e.g. in beach surveys and clean-ups). PMID:19124136

  12. Geographic risk factors for inter-river dispersal of Gyrodactylus salaris in fjord systems in Norway.

    PubMed

    Jansen, Peder A; Matthews, Louise; Toft, Nils

    2007-02-28

    Gyrodactylus salaris has been recorded in 46 Norwegian rivers since 1975 and is considered a threat to Atlantic salmon stocks. The primary introductions of G. salaris (primary infected rivers) have been accounted for by specific events, as reported in the literature. The parasite has subsequently dispersed to adjacent localities (secondary infected rivers). The objective of this paper is to address the occurrence of secondary infections by examining the hypothesis of inter-river dispersal of G. salaris. A dispersal model for the secondary river infections via migrating infected fish is proposed. Due to the limited tolerance of G. salaris to salinity, both freshwater inflow to dispersal pathways and dispersal distance were expected to influence the probability of inter-river dispersal. Eighteen rivers were categorised as primary infected rivers, 28 as secondary infected rivers, and 54 as rivers at risk. Four risk factors: the log10 freshwater inflow; the dispersal distance; the time at risk; and the salmon harvest were combined in a multi-variable logistic regression model of the probability of secondary infection. The final multi-variable model included log10 freshwater inflow (Wald chi-square = 9.93) and dispersal distance (Wald chi-square = 6.48). Receiver operating characteristic analyses of the final model supported freshwater inflow as a strong predictor of G. salaris infection status. The strong influence of the freshwater inflow on the probability of secondary infection adds further support to the hypothesis of inter-river dispersal of G. salaris through fjords. PMID:17432043

  13. Seasonal and Latitudinal Variations in Dissolved Methane from 42 Lakes along a North-South Transect in Alaska

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Armando Sepulveda-Jauregui,* Katey M. Walter Anthony,* Karla Martinez-Cruz,* ** Peter Anthony,* and Frederic Thalasso**. * Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, Alaska. ** Biotechnology and Bioengineering Department, Cinvestav, Mexico city, D. F., Mexico. Northern lakes are important reservoirs and sources to the atmosphere of methane (CH4), a potent greenhouse gas. It is estimated that northern lakes (> 55 °N) contribute about 20% of the total global lake methane emissions, and that emissions from these lakes will increase with climate warming. Temperature rise enhances methane production directly by providing the kinetic energy to methanogenesis, and indirectly by supplying organic matter from thawing permafrost. Warmer lakes also store less methane since methane's solubility is inversely related to temperature. Alaskan lakes are located in three well-differentiated permafrost classes: yedoma permafrost with high labile carbon stocks, non-yedoma permafrost with lower carbon stocks, and areas without permafrost, also with generally lower carbon stocks. We sampled dissolved methane from 42 Alaskan lakes located in these permafrost cover classes along a north-south Alaska transect from Prudhoe Bay to the Kenai Peninsula during open-water conditions in summer 2011. We sampled 26 of these lakes in April, toward the end of the winter ice-covered period. Our results indicated that the largest dissolved methane concentrations occurred in interior Alaska thermokarst lakes formed in yedoma-type permafrost during winter and summer, with maximal concentrations of 17.19 and 12.76 mg L-1 respectively. In these lakes, emission of dissolved gases as diffusion during summer and storage release in spring were 18.4% and 17.4% of the annual emission budget, while ebullition (64.2 %) comprised the rest. Dissolved oxygen was inversely correlated with dissolved methane concentrations in both seasons; the

  14. Alaska GeoFORCE, A New Geologic Adventure in Alaska

    NASA Astrophysics Data System (ADS)

    Wartes, D.

    2011-12-01

    RAHI, the Rural Alaska Honors Institute is a statewide, six-week, summer college-preparatory bridge program at the University of Alaska Fairbanks for Alaska Native and rural high school juniors and seniors. A program of rigorous academic activity combines with social, cultural, and recreational activities. Students are purposely stretched beyond their comfort levels academically and socially to prepare for the big step from home or village to a large culturally western urban campus. This summer RAHI is launching a new program, GeoFORCE Alaska. This outreach initiative is designed to increase the number and diversity of students pursuing STEM degree programs and entering the future high-tech workforce. It uses Earth science as the hook because most kids get excited about dinosaurs, volcanoes and earthquakes, but it includes physics, chemistry, math, biology and other sciences. Students will be recruited, initially from the Arctic North Slope schools, in the 8th grade to begin the annual program of approximately 8 days, the summer before their 9th grade year and then remain in the program for all four years of high school. They must maintain a B or better grade average and participate in all GeoFORCE events. The carrot on the end of the stick is an exciting field event each summer. Over the four-year period, events will include trips to Fairbanks, Arizona, Oregon and the Appalachians. All trips are focused on Earth science and include a 100+ page guidebook, with tests every night culminating with a final exam. GeoFORCE Alaska is being launched by UAF in partnership with the University of Texas at Austin, which has had tremendous success with GeoFORCE Texas. GeoFORCE Alaska will be managed by UAF's long-standing Rural Alaska Honors Insitute (RAHI) that has been successfully providing intense STEM educational opportunities for Alaskan high school students for almost 30 years. The Texas program, with adjustments for differences in culture and environment, will be

  15. Profile: American Indian/Alaska Native

    MedlinePlus

    ... million American Indians and Alaska Natives. Typically, this urban clientele has less accessibility to hospitals; health clinics ... IHS and tribal health programs. Studies on the urban American Indian and Alaska Native population have documented ...

  16. 76 FR 53151 - Alaska Native Claims Selection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-25

    ... Kuskokwim Corporation, Successor in Interest to Red Devil Incorporated. The decision approves the surface... Devil, Alaska, and are located in: Seward Meridian, Alaska T. 22 N., R. 44 W., Secs. 27 to 34,...

  17. Coalbed methane, Cook Inlet, south-central Alaska: A potential giant gas resource

    USGS Publications Warehouse

    Montgomery, S.L.; Barker, C.E.

    2003-01-01

    Cook Inlet Basin of south-central Alaska is a forearc basin containing voluminous Tertiary coal deposits with sufficient methane content to suggest a major coalbed gas resource. Coals ranging in thickness from 2 to 50 ft (0.6 to 15 m) and in gas content from 50 to 250 scf/ton (1.6 to 7.8 cm2/g) occur in Miocene-Oligocene fluvial deposits of the Kenai Group. These coals have been identified as the probable source of more than 8 tcf gas that has been produced from conventional sandstone reservoirs in the basin. Cook Inlet coals can be divided into two main groups: (1) those of bituminous rank in the Tyonek Formation that contain mainly thermogenic methane and are confined to the northeastern part of the basin (Matanuska Valley) and to deep levels elsewhere; and (2) subbituminous coals at shallow depths (<5000 ft [1524 m]) in the Tyonek and overlying Beluga formations, which contain mainly biogenic methane and cover most of the central and southern basin. Based on core and corrected cuttings-desorption analyses, gas contents average 230 scf/ton (7.2 cm2/g) for bituminous coals and 80 scf/ton (2.5 cm2/g) for subbituminous coals. Isotherms constructed for samples of both coal ranks suggest that bituminous coals are saturated with respect to methane, whereas subbituminous coals at shallow depths along the eroded west-central basin margin are locally unsaturated. A preliminary estimate of 140 tcf gas in place is derived for the basin.

  18. Landscape Genetics of Schistocephalus solidus Parasites in Threespine Stickleback (Gasterosteus aculeatus) from Alaska

    PubMed Central

    Sprehn, C. Grace; Blum, Michael J.; Quinn, Thomas P.; Heins, David C.

    2015-01-01

    The nature of gene flow in parasites with complex life cycles is poorly understood, particularly when intermediate and definitive hosts have contrasting movement potential. We examined whether the fine-scale population genetic structure of the diphyllobothriidean cestode Schistocephalus solidus reflects the habits of intermediate threespine stickleback hosts or those of its definitive hosts, semi-aquatic piscivorous birds, to better understand complex host-parasite interactions. Seventeen lakes in the Cook Inlet region of south-central Alaska were sampled, including ten in the Matanuska-Susitna Valley, five on the Kenai Peninsula, and two in the Bristol Bay drainage. We analyzed sequence variation across a 759 bp region of the mitochondrial DNA (mtDNA) cytochrome oxidase I region for 1,026 S. solidus individuals sampled from 2009-2012. We also analyzed allelic variation at 8 microsatellite loci for 1,243 individuals. Analysis of mtDNA haplotype and microsatellite genotype variation recovered evidence of significant population genetic structure within S. solidus. Host, location, and year were factors in structuring observed genetic variation. Pairwise measures revealed significant differentiation among lakes, including a pattern of isolation-by-distance. Bayesian analysis identified three distinct genotypic clusters in the study region, little admixture within hosts and lakes, and a shift in genotype frequencies over time. Evidence of fine-scale population structure in S. solidus indicates that movement of its vagile, definitive avian hosts has less influence on gene flow than expected based solely on movement potential. Observed patterns of genetic variation may reflect genetic drift, behaviors of definitive hosts that constrain dispersal, life history of intermediate hosts, and adaptive specificity of S. solidus to intermediate host genotype. PMID:25874710

  19. Malaspina Glacier, Alaska

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite covers an area of 55 by 40 kilometers (34 by 25 miles) over the southwest part of the Malaspina Glacier and Icy Bay in Alaska. The composite of infrared and visible bands results in the snow and ice appearing light blue, dense vegetation is yellow-orange and green, and less vegetated, gravelly areas are in orange. According to Dr. Dennis Trabant (U.S. Geological Survey, Fairbanks, Alaska), the Malaspina Glacier is thinning. Its terminal moraine protects it from contact with the open ocean; without the moraine, or if sea level rises sufficiently to reconnect the glacier with the ocean, the glacier would start calving and retreat significantly. ASTER data are being used to help monitor the size and movement of some 15,000 tidal and piedmont glaciers in Alaska. Evidence derived from ASTER and many other satellite and ground-based measurements suggests that only a few dozen Alaskan glaciers are advancing. The overwhelming majority of them are retreating.

    This ASTER image was acquired on June 8, 2001. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next six years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along-term research and

  20. Diverse Approaches USED to Characterize the Earthquake and Tsunami Hazards Along the Southern Alaska Continental Margin

    NASA Astrophysics Data System (ADS)

    Haeussler, P. J.; Witter, R. C.; Liberty, L. M.; Brothers, D. S.; Briggs, R. W.; Armstrong, P. A.; Freymueller, J. T.; Parsons, T.; Ryan, H. F.; Lee, H. J.; Roland, E. C.

    2014-12-01

    Earthquakes and tsunamis are the principal geohazards of southern Alaska. The entire margin has ruptured in megathrust earthquakes, including the M9.2 1964 event, and these earthquakes have launched deadly local and trans-Pacific tsunamis. Tsunamis have been by far the largest killer in these earthquakes. Moreover, the subduction zone displays a range in locking behavior from completely locked beneath Prince William Sound, to ­­­­nearly freely slipping beneath the Shumagin Islands. Characterizing earthquake-related tsunami sources requires a diverse set of methods, and we discuss several examples. One important source for tsunamis is from megathrust splay faults. The Patton Bay splay fault system ruptured during the 1964 earthquake and generated a tsunami that impacted coastlines tens of minutes after the earthquake. A combination of multibeam mapping, high-resolution and crustal-scale seismic data, thermochronology, and detrital zircon geochronology show focused exhumation along this splay fault system for the last 2-3 Ma. Moreover, this long term pattern of exhumation mimics the pattern of uplift in 1964. Submarine landslides are another example of a tsunami source. Numerous devastating slides were triggered by the 1964 earthquake. Multibeam bathymetry, bathymetry difference maps, high-resolution seismic data, and records of paleotsunamis in coastal marshes reveal a long history of submarine landsliding in the coastal fjords of Alaska. The Little Ice Age appears to have had a significant influence on the submarine landslides in the 1964 earthquake through increased sediment production, transport to fjord margins, and, locally, compaction by glacier advances. Glacial retreat before 1964 gave rise to over-steepened slopes susceptible to dynamic failure. Numerous blocks in the submarine landslides were particularly effective in generating high tsunami run up. Finally, regional tectonic displacements of the seafloor have launched trans-Pacific tsunamis. Coastal

  1. Trends in Alaska's People and Economy.

    ERIC Educational Resources Information Center

    Leask, Linda; Killorin, Mary; Martin, Stephanie

    This booklet provides data on Alaska's population, economy, health, education, government, and natural resources, including specific information on Alaska Natives. Since 1960, Alaska's population has tripled and become more diverse, more stable, older, less likely to be male or married, and more concentrated. About 69 percent of the population…

  2. 50 CFR 32.21 - Alaska.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 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 Interest Lands Conservation Act (Pub. L. 96-487, 94 Stat. 2371). Information regarding specific...

  3. 50 CFR 32.21 - Alaska.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 9 2014-10-01 2014-10-01 false Alaska. 32.21 Section 32.21 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) THE NATIONAL WILDLIFE REFUGE SYSTEM HUNTING AND FISHING Refuge-Specific Regulations for Hunting and Fishing § 32.21 Alaska. Alaska refuges are opened to...

  4. Some Books about Alaska Received in 1986.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau. Div. of State Libraries.

    This publication is an annotated listing of 143 books about Alaska or the Arctic, received by the Alaska Division of State Libraries in 1986. Most of the material is current or published in recent years, with the exception of government publications. Categories are juvenile, adult non-fiction, adult fiction, and reference. A few Alaska state and…

  5. 33 CFR 80.1705 - Alaska.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Alaska. 80.1705 Section 80.1705 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Alaska § 80.1705 Alaska. The 72 COLREGS shall apply on all the sounds,...

  6. Alexander Archipelago, Southeastern Alaska

    NASA Technical Reports Server (NTRS)

    2002-01-01

    West of British Columbia, Canada, and south of the Yukon Territory, the southeastern coastline of Alaska trails off into the islands of the Alexander Archipelago. The area is rugged and contains many long, U-shaped, glaciated valleys, many of which terminate at tidewater. The Alexander Archipelago is home to Glacier Bay National Park. The large bay that has two forks on its northern end is Glacier Bay itself. The eastern fork is Muir inlet, into which runs the Muir glacier, named for the famous Scottish-born naturalist John Muir. Glacier Bay opens up into the Icy Strait. The large, solid white area to the west is Brady Icefield, which terminates at the southern end in Brady's Glacier. To locate more interesting features from Glacier Bay National Park, take a look at the park service map. As recently as two hundred years ago, a massive ice field extended into Icy Strait and filled the Glacier Bay. Since that time, the area has experienced rapid deglaciation, with many large glaciers retreating 40, 60, even 80 km. While temperatures have increased in the region, it is still unclear whether the rapid recession is part of the natural cycle of tidewater glaciers or is an indicator of longer-term climate change. For more on Glacier Bay and climate change, read an online paper by Dr. Dorothy Hall, a MODIS Associate Science Team Member. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  7. Alaska Pipeline Insulation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Crude oil moving through the 800-mile Trans-Alaska Pipeline must be kept at a relatively high temperature, about 180 degrees Fahrenheit, to maintain the fluidity of the oil. In Arctic weather, that demands highly effective insulation. General Electric Co.'s Space Division, Valley Forge, Pennsylvania, provided it with a spinoff product called Therm-O-Trol. Shown being installed on the pipeline, Therm-O-Trol is a metal-bonded polyurethane foam especially formulated for Arctic insulation. A second GE spinoff product, Therm-O-Case, solved a related problem involved in bringing hot crude oil from 2,000-foot-deep wells to the surface without transferring oil heat to the surrounding permafrost soil; heat transfer could melt the frozen terrain and cause dislocations that might destroy expensive well casings. Therm-O-Case is a double-walled oil well casing with multi-layered insulation which provides an effective barrier to heat transfer. Therm-O-Trol and Therm-O-Case are members of a family of insulating products which stemmed from technology developed by GE Space Division in heat transferlthermal control work on Gemini, Apollo and other NASA programs.

  8. Alaska Energy Inventory Project: Consolidating Alaska's Energy Resources

    NASA Astrophysics Data System (ADS)

    Papp, K.; Clough, J.; Swenson, R.; Crimp, P.; Hanson, D.; Parker, P.

    2007-12-01

    Alaska has considerable energy resources distributed throughout the state including conventional oil, gas, and coal, and unconventional coalbed and shalebed methane, gas hydrates, geothermal, wind, hydro, and biomass. While much of the known large oil and gas resources are concentrated on the North Slope and in the Cook Inlet regions, the other potential sources of energy are dispersed across a varied landscape from frozen tundra to coastal settings. Despite the presence of these potential energy sources, rural Alaska is mostly dependent upon diesel fuel for both electrical power generation and space heating needs. At considerable cost, large quantities of diesel fuel are transported to more than 150 roadless communities by barge or airplane and stored in large bulk fuel tank farms for winter months when electricity and heat are at peak demands. Recent increases in the price of oil have severely impacted the price of energy throughout Alaska, and especially hard hit are rural communities and remote mines that are off the road system and isolated from integrated electrical power grids. Even though the state has significant conventional gas resources in restricted areas, few communities are located near enough to these resources to directly use natural gas to meet their energy needs. To address this problem, the Alaska Energy Inventory project will (1) inventory and compile all available Alaska energy resource data suitable for electrical power generation and space heating needs including natural gas, coal, coalbed and shalebed methane, gas hydrates, geothermal, wind, hydro, and biomass and (2) identify locations or regions where the most economic energy resource or combination of energy resources can be developed to meet local needs. This data will be accessible through a user-friendly web-based interactive map, based on the Alaska Department of Natural Resources, Land Records Information Section's (LRIS) Alaska Mapper, Google Earth, and Terrago Technologies' Geo

  9. Modern sedimentation in a rapidly warming fjord: Potter Cove, King George Island, Antarctica

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    The northern Antarctic Peninsula belongs to the fastest warming regions on earth. The winter-warming trend was strong and stable over the past 70 years. As a result, Potter Cove, a small fjord that opens into Maxwell Bay (King George Island, South Shetland Islands), shows significant environmental change. A former tidewater glacier (Fourcade Glacier) has retreated onto land exposing bedrock such as a small island close to the glacier front. It is suggested that the warming trend triggered excessive discharge of sediment-laden meltwaters in the form of turbid surface waters. The hypothesis for this study is that very fine-grained materials are present in Potter Cove and that meltwater plumes that exit Potter Cove can be traced downstream in the form of fans of fine-grained materials. In this study we investigate the modern sedimentation patterns in Potter Cove using hydroacoustics and seafloor samples to compare that with conditions from the past as recorded in sediment cores. Surface grain-size distributions reveal a distinct textural pattern in Potter Cove. Cluster analysis suggests 7 classes of sediment types. Four of them are unimodal, three classes show fine-skewed distributions with tendencies to bimodality. The finer sediment classes are found in the central inner part of the cove. The finest class (mode at 16 µm) forms only a small patch in the shelter of a small island. Sediments from close to the glacier front appear to be slightly depleted in fine-grained materials. From the glacier front to the outer fjord the sediments show influence of current sorting, i.e. the coarser mode becomes more significant and sorting increases. A sediment core from the deeper outer basin of Potter Cove reveals only one of the better-sorted, coarser classes that appears to form on the way from the glacier into the basin. There are 5 long sediment cores located less than 10 km off the mouth of Potter Cove in Maxwell Bay. All of which reveal sediments that belong either to the

  10. Mesozooplankton community development at elevated CO2 concentrations: results from a mesocosm experiment in an Arctic fjord

    NASA Astrophysics Data System (ADS)

    Niehoff, B.; Schmithüsen, T.; Knüppel, N.; Daase, M.; Czerny, J.; Boxhammer, T.

    2013-03-01

    The increasing CO2 concentration in the atmosphere caused by burning fossil fuels leads to increasing pCO2 and decreasing pH in the world ocean. These changes may have severe consequences for marine biota, especially in cold-water ecosystems due to higher solubility of CO2. However, studies on the response of mesozooplankton communities to elevated CO2 are still lacking. In order to test whether abundance and taxonomic composition change with pCO2, we have sampled nine mesocosms, which were deployed in Kongsfjorden, an Arctic fjord at Svalbard, and were adjusted to eight CO2 concentrations, initially ranging from 185 μatm to 1420 μatm. Vertical net hauls were taken weekly over about one month with an Apstein net (55 μm mesh size) in all mesocosms and the surrounding fjord. In addition, sediment trap samples, taken every second day in the mesocosms, were analysed to account for losses due to vertical migration and mortality. The taxonomic analysis revealed that meroplanktonic larvae (Cirripedia, Polychaeta, Bivalvia, Gastropoda, and Decapoda) dominated in the mesocosms while copepods (Calanus spp., Oithona similis, Acartia longiremis and Microsetella norvegica) were found in lower abundances. In the fjord copepods prevailed for most of our study. With time, abundance and taxonomic composition developed similarly in all mesocosms and the pCO2 had no significant effect on the overall community structure. Also, we did not find significant relationships between the pCO2 level and the abundance of single taxa. Changes in heterogeneous communities are, however, difficult to detect, and the exposure to elevated pCO2 was relatively short. We therefore suggest that future mesocosm experiments should be run for longer periods.

  11. Calculating Freshwater Input from Iceberg Melt in Greenlandic Fjords by Combining In Situ Observations of Iceberg Movement with High Resolution Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Sulak, D. J.; Sutherland, D.; Stearns, L. A.; Hamilton, G. S.

    2015-12-01

    Understanding fjord circulation in Greenland's outlet glacial fjords is crucial to explaining recent temporal and spatial variability in glacier dynamics, as well as freshwater transport on the continental shelf. The fjords are commonly assumed to exhibit a plume driven circulation that draws in warmer and saltier Atlantic-origin water toward the glacier at depth. Freshwater input at glacier termini directly drives this circulation and significantly influences water column stratification, which indirectly feeds back on the plume driven circulation. Previous work has focused on freshwater inputs from surface runoff and submarine melting, but the contribution from iceberg melt, a potentially important freshwater source, has not been quantified. Here, we develop a new technique combining in situ observations of movement from iceberg-mounted GPS units with multispectral satellite imagery from Landsat 8. The combination of datasets allows us to examine the details of iceberg movement and quantify mean residence times in a given fjord. We then use common melt rate parameterizations to estimate freshwater input for a given iceberg, utilizing novel satellite-derived iceberg distributions to scale up to a fjord-wide freshwater contribution. We apply this technique to Rink Isbræ and Kangerlussuup Sermia in west Greenland, and Helheim Glacier in southeast Greenland. The analysis can be rapidly expanded to look at other systems as well as seasonal and interannual changes in how icebergs affect the circulation and stratification of Greenland's outlet glacial fjords. Ultimately, this work will lead to a more complete understanding of the wide range of factors that control the observed regional variability in Greenland's glaciers.

  12. Effect of CO2 enrichment on bacterial metabolism in an Arctic fjord

    NASA Astrophysics Data System (ADS)

    Motegi, C.; Tanaka, T.; Piontek, J.; Brussaard, C. P. D.; Gattuso, J.-P.; Weinbauer, M. G.

    2013-05-01

    The anthropogenic increase of carbon dioxide (CO2) alters the seawater carbonate chemistry, with a decline of pH and an increase in the partial pressure of CO2 (pCO2). Although bacteria play a major role in carbon cycling, little is known about the impact of rising pCO2 on bacterial carbon metabolism, especially for natural bacterial communities. In this study, we investigated the effect of rising pCO2 on bacterial production (BP), bacterial respiration (BR) and bacterial carbon metabolism during a mesocosm experiment performed in Kongsfjorden (Svalbard) in 2010. Nine mesocosms with pCO2 levels ranging from ca. 180 to 1400 μatm were deployed in the fjord and monitored for 30 days. Generally BP gradually decreased in all mesocosms in an initial phase, showed a large (3.6-fold average) but temporary increase on day 10, and increased slightly after inorganic nutrient addition. Over the wide range of pCO2 investigated, the patterns in BP and growth rate of bulk and free-living communities were generally similar over time. However, BP of the bulk community significantly decreased with increasing pCO2 after nutrient addition (day 14). In addition, increasing pCO2 enhanced the leucine to thymidine (Leu : TdR) ratio at the end of experiment, suggesting that pCO2 may alter the growth balance of bacteria. Stepwise multiple regression analysis suggests that multiple factors, including pCO2, explained the changes of BP, growth rate and Leu : TdR ratio at the end of the experiment. In contrast to BP, no clear trend and effect of changes of pCO2 was observed for BR, bacterial carbon demand and bacterial growth efficiency. Overall, the results suggest that changes in pCO2 potentially influence bacterial production, growth rate and growth balance rather than the conversion of dissolved organic matter into CO2.

  13. Monitoring of a steep rockfall area experiencing fast displacements in Kåfjord, Northern Norway

    NASA Astrophysics Data System (ADS)

    Dreiås Majala, Gudrun; Harald Blikra, Lars; Skrede, Ingrid; Kristensen, Lene

    2016-04-01

    An unstable rockfall area in Kåfjord, Northern Norway, was recognized during periodic monitoring campaigns in July and early September 2015. The LiSALab ground based Interferometric Synthethic Aperture Radar (GB InSAR) from Ellegi were used. A relatively sharply defined steep area of 1200 m2 (6.000 - 12.000 m3) was documented to be in movement. Norwegian Water Resources and Energy Directorate (NVE) was at this point performing mitigation work in terms of an embarkment within the rockfall run-out area. The monitoring system was reinstalled and adjusted to perform continuous monitoring with an early-warning aim. The section for rockslide management in NVE was responsible for the monitoring and the warning to the municipality and Police. The displacements increased from about 1 mm/day in July to 3 cm/day in mid September. People were evalcuated due to increased velocities the 16th of September. The displacements continued to increase in several stages, and with a distinct accelleration the 2nd of October. The velocity peaked in a short window to more than 200 cm/day, and it ended with a partly frontal and sideway collapse of the unstable area. However, large parts of the area stabilized again, and the run-out lengths from the small rockfalls were limited. The GB InSAR system operated exceptionally well during the event, and were able to follow continuously the displacements during the accelleration stage until collapse as the processing time window was frequently adjusted to the changes in velocity. We were also able to follow inidividual rockfalls from the images - primarily as the rockfall impact points on the slope below showed up clearly on the radar images. The area continued to stabilize due to falling temperatures, and the mitigation work were finished during the fall. The displacements seem to be correlated to the increasing temperatures in late summer and precipitation events.

  14. Vertical mixing and internal wave energy fluxes in a sill fjord

    NASA Astrophysics Data System (ADS)

    Staalstrøm, André; Røed, Lars Petter

    2016-07-01

    We consider the distribution and level of local vertical mixing inside of the Drøbak Sill in the Oslofjord, Norway. The work is motivated by observations of long periods (∼years) of hypoxic or even anoxic conditions in the innermost basin, episodes attributed to weak vertical mixing. In line with earlier work on the subject we assume that the local vertical mixing level inside of the sill is predominantly determined by the loss of energy of propagating, tidally-induced internal waves whose source is the sill region. To investigate possible differences in vertical mixing we estimate the eddy diffusivity in the various basins based on model simulations and observations using three methods whereby the eddy diffusion coefficient is estimated. The model we use is an ultra high-resolution version of the three-dimensional, hydrostatic ocean model ROMS forced solely by barotropic tide well outside of the sill. To evaluate the sensitivity of the model results we perform sensitivity experiments in which the mesh size and various parameters and parameterizations are varied. We find indeed that the internal waves lose most of their energy before they reach the innermost basin, and hence set the scene for long periods of no deep water renewal. The sensitivity experiments reveal that it is important that the model's mesh size is small enough to resolve the dominant wavelengths of the topography. Moreover, we find that the strength of the turbulence production and hence the mixing depends on the initially chosen stratification. The method we use is generic and may be applied to any sill fjord.

  15. Implementation of marine spatial planning in shellfish aquaculture management: modeling studies in a Norwegian fjord.

    PubMed

    Filgueira, Ramon; Grant, Jon; Strand, Øivind

    2014-06-01

    Shellfish carrying capacity is determined by the interaction of a cultured species with its ecosystem, which is strongly influenced by hydrodynamics. Water circulation controls the exchange of matter between farms and the adjacent areas, which in turn establishes the nutrient supply that supports phytoplankton populations. The complexity of water circulation makes necessary the use of hydrodynamic models with detailed spatial resolution in carrying capacity estimations. This detailed spatial resolution also allows for the study of processes that depend on specific spatial arrangements, e.g., the most suitable location to place farms, which is crucial for marine spatial planning, and consequently for decision support systems. In the present study, a fully spatial physical-biogeochemical model has been combined with scenario building and optimization techniques as a proof of concept of the use of ecosystem modeling as an objective tool to inform marine spatial planning. The object of this exercise was to generate objective knowledge based on an ecosystem approach to establish new mussel aquaculture areas in a Norwegian fjord. Scenario building was used to determine the best location of a pump that can be used to bring nutrient-rich deep waters to the euphotic layer, increasing primary production, and consequently, carrying capacity for mussel cultivation. In addition, an optimization tool, parameter estimation (PEST), was applied to the optimal location and mussel standing stock biomass that maximize production, according to a preestablished carrying capacity criterion. Optimization tools allow us to make rational and transparent decisions to solve a well-defined question, decisions that are essential for policy makers. The outcomes of combining ecosystem models with scenario building and optimization facilitate planning based on an ecosystem approach, highlighting the capabilities of ecosystem modeling as a tool for marine spatial planning. PMID:24988780

  16. The silica cycle in a Northeast Pacific fjord; the role of biological resuspension

    NASA Astrophysics Data System (ADS)

    Katz, Timor; Yahel, Gitai; Tunnicliffe, Verena; Herut, Barak; Whitney, Frank; Snelgrove, Paul V. R.; Lazar, Boaz

    2016-09-01

    This study is a quantitative assessment of the role fish-induced bio-resuspension plays in the silica cycle of coastal waters. We used new, published and archived oceanographic data to construct a comprehensive silica budget for Saanich Inlet (Vancouver Island, Canada), a highly productive Northeast Pacific fjord, where siliceous diatoms dominate primary productivity. Anoxia in the deep water of the inlet persists during most of the year, precluding animal life, whereas abundant groundfish continuously rework and resuspend bottom sediments in the shallower, oxygenated margins. This resuspension transfers settled biogenic silica fragments from the sediment, where they are immersed in porewater that is rich with dissolved silica, to the overlying water, where the much lower concentrations accelerate their dissolution rate. The budget shows that Saanich Inlet sediments constitute a sink for approximately 250 × 106 mol Si y-1. Most of this Si enters the inlet in advected, siliceous phytoplankton. Sediment resuspension by groundfish in the oxygenated margins of Saanich Inlet generates about 50% of the total flux of dissolved silica from the inlet seafloor. This resuspension also facilitates a massive transport of biogenic silica from the margins to the anoxic basin, where approximately 90% of all the biogenic silica is buried. The excess dissolution caused by fish activity reduces the burial efficiency of biogenic silica in the entire inlet sediments by about 20%. This case study emphasizes the link between the silica cycle and groundfish activity. Based on this study and because biological resuspension occurs in most regions of the ocean, we recommend that it will be taken into account when budgeting the silica cycle, and potentially other geochemical cycles, in marine environments.

  17. A Modeling Study of Hydrodynamic Circulation in a Fjord of the Pacific Northwest

    SciTech Connect

    Wang, Taiping; Yang, Zhaoqing

    2012-10-01

    Increased eutrophication and degraded water quality in estuarine and coastal waters have been a worldwide environmental concern. While it is commonly accepted that anthropogenic impact plays a major role in many emerging water quality issues, natural conditions such as restricted water circulations controlled by geometry may also substantially contribute to unfavorable water quality in certain ecosystems. To elucidate the contributions from different factors, a hydrodynamic-water quality model that integrates both physical transport and pollutant loadings is particularly warranted. A preliminary modeling study using the Environmental Fluid Dynamic Code (EFDC) is conducted to investigate hydrodynamic circulation and low dissolved oxygen (DO) in Hood Canal, a representative fjord in the U.S. Pacific Northwest. Because the water quality modeling work is still ongoing, this paper focuses on the progress in hydrodynamic modeling component. The hydrodynamic model has been set up using the publicly available forcing data and was calibrated against field observations or NOAA predictions for tidal elevation, current, salinity and temperature. The calibrated model was also used to estimate physical transport timescales such as residence time in the estuary. The preliminary model results demonstrate that the EFDC Hood Canal model is capable of capturing the general circulation patterns in Hood Canal, including weak tidal current and strong vertical stratification. The long residence time (i.e., on the order of 100 days for the entire estuary) also indicates that restricted water circulation could contribute to low DO in the estuary and also makes the system especially susceptible to anthropogenic disturbance, such as excess nutrient input.

  18. Alaska volcanoes guidebook for teachers

    USGS Publications Warehouse

    Adleman, Jennifer N.

    2011-01-01

    Alaska’s volcanoes, like its abundant glaciers, charismatic wildlife, and wild expanses inspire and ignite scientific curiosity and generate an ever-growing source of questions for students in Alaska and throughout the world. Alaska is home to more than 140 volcanoes, which have been active over the last 2 million years. About 90 of these volcanoes have been active within the last 10,000 years and more than 50 of these have been active since about 1700. The volcanoes in Alaska make up well over three-quarters of volcanoes in the United States that have erupted in the last 200 years. In fact, Alaska’s volcanoes erupt so frequently that it is almost guaranteed that an Alaskan will experience a volcanic eruption in his or her lifetime, and it is likely they will experience more than one. It is hard to imagine a better place for students to explore active volcanism and to understand volcanic hazards, phenomena, and global impacts. Previously developed teachers’ guidebooks with an emphasis on the volcanoes in Hawaii Volcanoes National Park (Mattox, 1994) and Mount Rainier National Park in the Cascade Range (Driedger and others, 2005) provide place-based resources and activities for use in other volcanic regions in the United States. Along the lines of this tradition, this guidebook serves to provide locally relevant and useful resources and activities for the exploration of numerous and truly unique volcanic landscapes in Alaska. This guidebook provides supplemental teaching materials to be used by Alaskan students who will be inspired to become educated and prepared for inevitable future volcanic activity in Alaska. The lessons and activities in this guidebook are meant to supplement and enhance existing science content already being taught in grade levels 6–12. Correlations with Alaska State Science Standards and Grade Level Expectations adopted by the Alaska State Department of Education and Early Development (2006) for grades six through eleven are listed at

  19. A management tool for assessing aquaculture environmental impacts in Chilean Patagonian Fjords: integrating hydrodynamic and pellets dispersion models.

    PubMed

    Tironi, Antonio; Marin, Víctor H; Campuzano, Francisco J

    2010-05-01

    This article introduces a management tool for salmon farming, with a scope in the local sustainability of salmon aquaculture of the Aysen Fjord, Chilean Patagonia. Based on Integrated Coastal Zone Management (ICZM) principles, the tool combines a large 3-level nested hydrodynamic model, a particle tracking module and a GIS application into an assessment tool for particulate waste dispersal of salmon farming activities. The model offers an open source alternative to particulate waste modeling and evaluation, contributing with valuable information for local decision makers in the process of locating new facilities and monitoring stations. PMID:20333379

  20. A Management Tool for Assessing Aquaculture Environmental Impacts in Chilean Patagonian Fjords: Integrating Hydrodynamic and Pellets Dispersion Models

    NASA Astrophysics Data System (ADS)

    Tironi, Antonio; Marin, Víctor H.; Campuzano, Francisco J.

    2010-05-01

    This article introduces a management tool for salmon farming, with a scope in the local sustainability of salmon aquaculture of the Aysen Fjord, Chilean Patagonia. Based on Integrated Coastal Zone Management (ICZM) principles, the tool combines a large 3-level nested hydrodynamic model, a particle tracking module and a GIS application into an assessment tool for particulate waste dispersal of salmon farming activities. The model offers an open source alternative to particulate waste modeling and evaluation, contributing with valuable information for local decision makers in the process of locating new facilities and monitoring stations.

  1. Aragonite saturation states and pH in western Norwegian fjords: seasonal cycles and controlling factors, 2005-2009

    NASA Astrophysics Data System (ADS)

    Omar, Abdirahman M.; Skjelvan, Ingunn; Rune Erga, Svein; Olsen, Are

    2016-07-01

    The uptake of anthropogenic carbon dioxide (CO2) by the ocean leads to a process known as ocean acidification (OA), which lowers the aragonite saturation state (ΩAr) and pH, and this is poorly documented in coastal environments including fjords due to lack of appropriate observations.

    Here we use weekly underway data from the Voluntary Observing Ships (VOS) program covering the period 2005-2009 combined with data from research cruises to estimate ΩAr and pH values in several adjacent western Norwegian fjords, and to evaluate how seawater CO2 chemistry drives their variations in response to physical and biological factors.

    The OA parameters in the surface waters of the fjords are subject to strong seasonal and spatially coherent variations. These changes are governed by the seasonal changes in temperature, salinity, formation and decay of organic matter, and vertical mixing with deeper, carbon-rich coastal water. Annual mean pH and ΩAr values were 8.13 and 2.21, respectively. The former varies from minimum values ( ≈ 8.05) in late December - early January to maximum values of around 8.2 during early spring (March-April) as a consequence of the phytoplankton spring bloom, which reduces dissolved inorganic carbon (DIC). In the following months, pH decreases in response to warming. This thermodynamic decrease in pH is reinforced by the deepening of the mixed layer, which enables carbon-rich coastal water to reach the surface, and this trend continues until the low winter values of pH are reached again. ΩAr, on the other hand, reaches its seasonal maximum (> 2.5) in mid- to late summer (July-September), when the spring bloom is over and pH is decreasing. The lowest ΩAr values ( ≈ 1.3-1.6) occur during winter (January-March), when both pH and sea surface temperature (SST) are low and DIC is its highest. Consequently, seasonal ΩAr variations align with those of SST and salinity normalized DIC (nDIC).

    We demonstrate that

  2. Teshekpuk Lake, Alaska

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This ASTER image of Teshekpuk Lake on Alaska's North Slope, within the National Petroleum Reserve, was acquired on August 15, 2000. It covers an area of 58.7 x 89.9 km, and is centered near 70.4 degrees north latitude, 153 degrees west longitude.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 58.7 by 89.9 kilometers (36.4 by 55.7 miles) Location: 70.4 degrees North latitude, 153 degrees West longitude Orientation: North at top Image Data: ASTER Bands 3, 2, and 1 Original Data Resolution: ASTER 30 meters (98.4 feet) Dates Acquired: August 15, 2000

  3. Alaska Resource Data File, Talkeetna Mountains quadrangle, Alaska

    USGS Publications Warehouse

    Rogers, Robert K.; Schmidt, Jeanine 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.

  4. Evidence and implications of recent and projected climate change in Alaska's forest ecosystems

    USGS Publications Warehouse

    Wolken, Jane M.; Hollingsworth, Teresa N.; Rupp, T. Scott; Chapin, Stuart III; Trainor, Sarah F.; Barrett, Tara M.; Sullivan, Patrick F.; McGuire, A. David; Euskirchen, Eugénie S.; Hennon, Paul E.; Beever, Erik A.; Conn, Jeff S.; Crone, Lisa K.; D'Amore, David V.; Fresco, Nancy; Hanley, Thomas A.; Kielland, Knut; Kruse, James J.; Patterson, Trista; Schuur, Edward A.G.; Verbyla, David L.; Yarie, John

    2011-01-01

    The structure and function of Alaska's forests have changed significantly in response to a changing climate, including alterations in species composition and climate feedbacks (e.g., carbon, radiation budgets) that have important regional societal consequences and human feedbacks to forest ecosystems. In this paper we present the first comprehensive synthesis of climate-change impacts on all forested ecosystems of Alaska, highlighting changes in the most critical biophysical factors of each region. We developed a conceptual framework describing climate drivers, biophysical factors and types of change to illustrate how the biophysical and social subsystems of Alaskan forests interact and respond directly and indirectly to a changing climate. We then identify the regional and global implications to the climate system and associated socio-economic impacts, as presented in the current literature. Projections of temperature and precipitation suggest wildfire will continue to be the dominant biophysical factor in the Interior-boreal forest, leading to shifts from conifer- to deciduous-dominated forests. Based on existing research, projected increases in temperature in the Southcentral- and Kenai-boreal forests will likely increase the frequency and severity of insect outbreaks and associated wildfires, and increase the probability of establishment by invasive plant species. In the Coastal-temperate forest region snow and ice is regarded as the dominant biophysical factor. With continued warming, hydrologic changes related to more rapidly melting glaciers and rising elevation of the winter snowline will alter discharge in many rivers, which will have important consequences for terrestrial and marine ecosystem productivity. These climate-related changes will affect plant species distribution and wildlife habitat, which have regional societal consequences, and trace-gas emissions and radiation budgets, which are globally important. Our conceptual framework facilitates

  5. Information needs for habitat protection: Marbled murrelet habitat identification. Restoration project 93051b. Exxon Valdez oil spill restoration project final report

    SciTech Connect

    Kuletz, K.J.; Marks, D.K.; Naslund, N.L.; Goodson, N.G.; Cody, M.B.

    1994-12-01

    To define murrelet nesting habitat in southcentral Alaska, we surveyed inland activity of murrelets and measured habitat features between 1991 and 1993, in Prince William Sound, Kenai Fjords National Park and Afognak Island, Alaska (N=262 sites). Using all study areas, we developed statistical models that explain variation in murrelet activity levels and predict the occurrence of behaviors indicative of nesting, based on temporal, geographic, topographic, weather and habitat variables. The multiple regression analyses explained 52 percent of the variation in murrelet activity level. Stepwise logistic regression was used to identify variables that could predict the occurrence of nesting behaviors. The best model included survey method (from a boat, shore or inland), location relative to the head of a bay, tree diameter and number of potential nesting platforms on trees. Overall, the features indicative of murrelet nesting habitat included low elevation locations near the heads of bays, with extensive forest cover of large old-growth trees.

  6. Tuberculosis among Children in Alaska.

    ERIC Educational Resources Information Center

    Gessner, Bradford D.

    1997-01-01

    The incidence of tuberculosis among Alaskan children under 15 was more than twice the national rate, with Alaska Native children showing a much higher incidence. Children with household exposure to adults with active tuberculosis had a high risk of infection. About 22 percent of pediatric tuberculosis cases were identified through school…

  7. Tularemia in Alaska, 1938 - 2010

    PubMed Central

    2011-01-01

    Tularemia is a serious, potentially life threatening zoonotic disease. The causative agent, Francisella tularensis, is ubiquitous in the Northern hemisphere, including Alaska, where it was first isolated from a rabbit tick (Haemophysalis leporis-palustris) in 1938. Since then, F. tularensis has been isolated from wildlife and humans throughout the state. Serologic surveys have found measurable antibodies with prevalence ranging from < 1% to 50% and 4% to 18% for selected populations of wildlife species and humans, respectively. We reviewed and summarized known literature on tularemia surveillance in Alaska and summarized the epidemiological information on human cases reported to public health officials. Additionally, available F. tularensis isolates from Alaska were analyzed using canonical SNPs and a multi-locus variable-number tandem repeats (VNTR) analysis (MLVA) system. The results show that both F. t. tularensis and F. t. holarctica are present in Alaska and that subtype A.I, the most virulent type, is responsible for most recently reported human clinical cases in the state. PMID:22099502

  8. Tularemia in Alaska, 1938 - 2010.

    PubMed

    Hansen, Cristina M; Vogler, Amy J; Keim, Paul; Wagner, David M; Hueffer, Karsten

    2011-01-01

    Tularemia is a serious, potentially life threatening zoonotic disease. The causative agent, Francisella tularensis, is ubiquitous in the Northern hemisphere, including Alaska, where it was first isolated from a rabbit tick (Haemophysalis leporis-palustris) in 1938. Since then, F. tularensis has been isolated from wildlife and humans throughout the state. Serologic surveys have found measurable antibodies with prevalence ranging from < 1% to 50% and 4% to 18% for selected populations of wildlife species and humans, respectively. We reviewed and summarized known literature on tularemia surveillance in Alaska and summarized the epidemiological information on human cases reported to public health officials. Additionally, available F. tularensis isolates from Alaska were analyzed using canonical SNPs and a multi-locus variable-number tandem repeats (VNTR) analysis (MLVA) system. The results show that both F. t. tularensis and F. t. holarctica are present in Alaska and that subtype A.I, the most virulent type, is responsible for most recently reported human clinical cases in the state. PMID:22099502

  9. A Title I Refinement: Alaska.

    ERIC Educational Resources Information Center

    Hazelton, Alexander E.; And Others

    Through joint planning with a number of school districts and the Region X Title I Technical Assistance Center, and with the help of a Title I Refinement grant, Alaska has developed a system of data storage and retrieval using microcomputers that assists small school districts in the evaluation and reporting of their Title I programs. Although this…

  10. Adventures in the Alaska Economy.

    ERIC Educational Resources Information Center

    Jackstadt, Steve; Huskey, Lee

    This publication was developed to increase students' understanding of basic economic concepts and the historical development of Alaska's economy. Comics depict major historical events as they occurred, but specific characters are fictionalized. Each of nine episodes is accompanied by several pages of explanatory text, which enlarges on the episode…

  11. Leafhoppers and potatoes in Alaska

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research conducted from 2004 to 2006 in the main potato production areas of Alaska resulted in the identification of 41 leafhopper species associated with agricultural settings. Two species, Davisonia snowi (Dorst) and Macrosteles fascifrons (Stål), made up approximately 60% of the total number of i...

  12. Alaska and Bering Sea Bloom

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Alaska was relatively clear as was part of the Bering Sea where the aquamarine bloom is still visible in this SeaWiFS image. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  13. Effects of the earthquake of March 27, 1964, on air and water transport, communications, and utilities systems in south-central Alaska: Chapter B in The Alaska earthquake, March 27, 1964: effects on transportation, communications, and utilities

    USGS Publications Warehouse

    Eckel, Edwin B.

    1967-01-01

    The earthquake of March 27, 1964, wrecked or severely hampered all forms of transportation, all utilities, and all communications systems over a very large part of south-central Alaska. Effects on air transportation were minor as compared to those on the water, highway, and railroad transport systems. A few planes were damaged or wrecked by seismic vibration or by flooding. Numerous airport facilities were damaged by vibration or by secondary effects of the earthquake, notably seismic sea and landslide-generated waves, tectonic subsidence, and compaction. Nearly all air facilities were partly or wholly operational within a few hours after the earthquake. The earthquake inflicted enormous damage on the shipping industry, which is indispensable to a State that imports fully 90 percent of its requirements—mostly by water—and whose largest single industry is fishing. Except for those of Anchorage, all port facilities in the earthquake-affected area were destroyed or made inoperable by submarine slides, waves, tectonic uplift, and fire. No large vessels were lost, but more than 200 smaller ones (mostly crab or salmon boats) were lost or severely damaged. Navigation aids were destroyed, and hitherto well-known waterways were greatly altered by uplift or subsidence. All these effects wrought far-reaching changes in the shipping economy of Alaska, many of them to its betterment. Virtually all utilities and communications in south-central Alaska were damaged or wrecked by the earthquake, but temporary repairs were effected in remarkably short times. Communications systems were silenced almost everywhere by loss of power or by downed lines; their place was quickly taken by a patchwork of self-powered radio transmitters. A complex power-generating system that served much of the stricken area from steam, diesel, and hydrogenerating plants was disrupted in many places by vibration damage to equipment and by broken transmission lines. Landslides in Anchorage broke gas

  14. Holocene primary productivity and the atmosphere/ocean linkage in the Gulf of Alaska

    NASA Astrophysics Data System (ADS)

    Addison, J. A.; Finney, B.; Anderson, L.; Barron, J. A.; Hayes, S. M.; Sliwinski, M.; Mix, A. C.

    2015-12-01

    Recent work in the temperate fjords of the Gulf of Alaska, located in the subarctic northeast Pacific Ocean, has demonstrated a positive link between modern atmosphere/ocean dynamics and accumulation of biogenic sediments during the last 100 years, where intensified Aleutian Low atmospheric pressure cell regimes correspond to peaks in export primary productivity (Addison et al., 2013). Here, this work is extended by examining the last 7500 years of biogenic sedimentation from marine sediment core EW0408-33JC (57.16°N, 135.36°W, 144 m water depth), which is constrained by 17 age-control points spaced every ~500 years. We use bromine (Br) intensities measured by core-scanning XRF with a 2-mm sampling resolution as a geochemical proxy for past primary productivity. These Br intensities are calibrated to organic Br concentrations using a combination of quantitative WD-XRF methods and synchrotron-radiation Br speciation studies, with cross-verification provided by low-resolution analyses of other productivity proxies, including biogenic silica (opal), total organic carbon (TOC), and organic matter δ13C ratios. Our findings indicate distinct centennial-to-millennial changes, with positive productivity excursions between 7500-7000, 6500-6000, 5000-3500, 2500-1500, and 1000-500 INTCAL13 yr BP. We compare the timing of these excursions against a compilation of marine and terrestrial paleoclimate records sensitive to forcing by the Aleutian Low to determine if the positive relationship between atmosphere/ocean dynamics and marine primary productivity has remained consistent over the last 7500 years. Other potential forcing mechanisms (e.g., solar insolation, irradiance) are also considered. Reference: Addison, J.A., Finney, B., Jaeger, J., Stoner, J., Norris, R., & Hangsterfer, A., 2013, Integrating satellite observations and modern climate measurements with the recent sedimentary record: an example from Southeast Alaska. JGR-Oceans, v. 118, 18 pgs.

  15. Volcano seismicity in Alaska

    NASA Astrophysics Data System (ADS)

    Buurman, Helena

    I examine the many facets of volcano seismicity in Alaska: from the short-lived eruption seismicity that is limited to only the few weeks during which a volcano is active, to the seismicity that occurs in the months following an eruption, and finally to the long-term volcano seismicity that occurs in the years in which volcanoes are dormant. I use the rich seismic dataset that was recorded during the 2009 eruption of Redoubt Volcano to examine eruptive volcano seismicity. I show that the progression of magma through the conduit system at Redoubt could be readily tracked by the seismicity. Many of my interpretations benefited greatly from the numerous other datasets collected during the eruption. Rarely was there volcanic activity that did not manifest itself in some way seismically, however, resulting in a remarkably complete chronology within the seismic record of the 2009 eruption. I also use the Redoubt seismic dataset to study post-eruptive seismicity. During the year following the eruption there were a number of unexplained bursts of shallow seismicity that did not culminate in eruptive activity despite closely mirroring seismic signals that had preceded explosions less than a year prior. I show that these episodes of shallow seismicity were in fact related to volcanic processes much deeper in the volcanic edifice by demonstrating that earthquakes that were related to magmatic activity during the eruption were also present during the renewed shallow unrest. These results show that magmatic processes can continue for many months after eruptions end, suggesting that volcanoes can stay active for much longer than previously thought. In the final chapter I characterize volcanic earthquakes on a much broader scale by analyzing a decade of continuous seismic data across 46 volcanoes in the Aleutian arc to search for regional-scale trends in volcano seismicity. I find that volcanic earthquakes below 20 km depth are much more common in the central region of the arc

  16. Negative effects of blue mussel ( Mytilus edulis) presence in eelgrass ( Zostera marina) beds in Flensborg fjord, Denmark

    NASA Astrophysics Data System (ADS)

    Vinther, Hanne Fogh; Laursen, Jens Sund; Holmer, Marianne

    2008-03-01

    The effect of blue mussel ( Mytilus edulis) presence in eelgrass ( Zostera marina) beds was studied from June 2004 to July 2005 in Flensborg fjord, Denmark. The field experiments were conducted at two stations, one with only Z. marina (Eelgrass station) present and one where M. edulis were present in the Z. marina beds (Mixed station). Zostera marina parameters were measured (growth of leaves, shoot density, leaf length, and nutrient content) in combination with epiphyte cover and sediment parameters (sulphate reduction rates, sediment nutrient fluxes, organic content, C, N and P content) to examine possible positive and negative effects of the mussels on eelgrass performance. The fluxes of ammonium from the sediments were stimulated at all sampling dates at the Mixed station, and possibly stimulated epiphyte growth at this station. Further 15N signals in epiphytes from the Mixed station suggested that excretion products from the mussels were important nitrogen sources at this station. Sulphate reduction rates were enhanced at the Mixed station and also sediment sulphide concentrations increased under mussel influence, which may have resulted in sulphide toxicity and decreased growth of Z. marina at this station. The study indicates that for Z. marina beds in Flensborg Fjord the effects of M. edulis in seagrass beds are primarily negative, and raises the question whether this leads to negative effects on the stability and expansion of Z. marina beds.

  17. Earthquake and flood-induced turbidites in the Saguenay Fjord (Québec): a Holocene paleoseismicity record

    NASA Astrophysics Data System (ADS)

    St-Onge, Guillaume; Mulder, Thierry; Piper, David J. W.; Hillaire-Marcel, Claude; Stoner, Joseph S.

    2004-02-01

    A 38 m-long piston core from the deep basin of the Saguenay Fjord, Québec, recorded rapidly deposited layers (RDL) interpreted to represent major floods and earthquakes over the past ˜7200 years. High-resolution physical, magnetic and sedimentological analyses revealed at least 14 RDL, generally with a sandy base and a light gray color, interbedded with hemipelagic sediments. Digital X-radiography and grain size analyses at <1 cm spacing showed that six RDL have normal grading and likely resulted from earthquake-triggered slumps. Six other RDL have a similar normally graded basal bed, overlain by a coarsening-upward unit that underlies a fining-upward unit, interpreted as a deposit of flood-induced hyperpycnal flow. By analogy with the deposits that followed the AD 1663 earthquake, such beds are inferred to result from the breaching and rapid draining of a natural dam generated by an earthquake-triggered landslide. Based on this interpretation, the chronology derived from paleomagnetic secular variation, paleointensity and one AMS 14C date suggests that earthquake frequency was dramatically reduced at ˜4 ka, consistent with ice-load modeling during deglaciation in Eastern Canada. This study demonstrates that hyperpycnal and slump-generated turbidites can be readily distinguished in small basins such as the Saguenay Fjord and that hyperpycnal turbidites tend to be much thicker, because of greater flow duration and constriction.

  18. Modeling the effects and uncertainties of contaminated sediment remediation scenarios in a Norwegian fjord by Markov chain Monte Carlo simulation.

    PubMed

    Saloranta, Tuomo M; Armitage, James M; Haario, Heikki; Naes, Kristoffer; Cousins, Ian T; Barton, David N

    2008-01-01

    Multimedia environmental fate models are useful tools to investigate the long-term impacts of remediation measures designed to alleviate potential ecological and human health concerns in contaminated areas. Estimating and communicating the uncertainties associated with the model simulations is a critical task for demonstrating the transparency and reliability of the results. The Extended Fourier Amplitude Sensitivity Test(Extended FAST) method for sensitivity analysis and Bayesian Markov chain Monte Carlo (MCMC) method for uncertainty analysis and model calibration have several advantages over methods typically applied for multimedia environmental fate models. Most importantly, the simulation results and their uncertainties can be anchored to the available observations and their uncertainties. We apply these techniques for simulating the historical fate of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Grenland fjords, Norway, and for predicting the effects of different contaminated sediment remediation (capping) scenarios on the future levels of PCDD/Fs in cod and crab therein. The remediation scenario simulations show that a significant remediation effect can first be seen when significant portions of the contaminated sediment areas are cleaned up, and that increase in capping area leads to both earlier achievement of good fjord status and narrower uncertainty in the predicted timing for this. PMID:18350897

  19. Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez

    NASA Astrophysics Data System (ADS)

    Parsons, Tom; Geist, Eric L.; Ryan, Holly F.; Lee, Homa J.; Haeussler, Peter J.; Lynett, Patrick; Hart, Patrick E.; Sliter, Ray; Roland, Emily

    2014-11-01

    Like many subduction zone earthquakes, the deadliest aspects of the 1964 M = 9.2 Alaska earthquake were the tsunamis it caused. The worst of these were generated by local submarine landslides induced by the earthquake. These caused high runups, engulfing several coastal towns in Prince William Sound. In this paper, we study one of these cases in detail, the Port Valdez submarine landslide and tsunami. We combine eyewitness reports, preserved film, and careful posttsunami surveys with new geophysical data to inform numerical models for landslide tsunami generation. We review the series of events as recorded at Valdez old town and then determine the corresponding subsurface events that led to the tsunami. We build digital elevation models of part of the pretsunami and posttsunami fjord-head delta. Comparing them reveals a ~1500 m long region that receded 150 m to the east, which we interpret as the primary delta landslide source. Multibeam imagery and high-resolution seismic reflection data identify a ~400 m wide chute with hummocky deposits at its terminus, which may define the primary slide path. Using these elements we run hydrodynamic models of the landslide-driven tsunamis that match observations of current direction, maximum inundation, and wave height at Valdez old town. We speculate that failure conditions at the delta front may have been influenced by manmade changes in drainage patterns as well as the fast retreat of Valdez and other glaciers during the past century.

  20. Glaciological and marine geological controls on terminus dynamics of Hubbard Glacier, southeast Alaska

    USGS Publications Warehouse

    Stearns, Leigh A.; Hamilton, Gordon S.; van der Veen, C. J.; Finnegan, D. C.; O'Neel, Shad; Scheick, J. B.; Lawson, D. E.

    2015-01-01

    Hubbard Glacier, located in southeast Alaska, is the world's largest non-polar tidewater glacier. It has been steadily advancing since it was first mapped in 1895; occasionally, the advance creates an ice or sediment dam that blocks a tributary fjord (Russell Fiord). The sustained advance raises the probability of long-term closure in the near-future, which will strongly impact the ecosystem of Russell Fiord and the nearby community of Yakutat. Here, we examine a 43-year record of flow speeds and terminus position to understand the large-scale dynamics of Hubbard Glacier. Our long-term record shows that the rate of terminus advance has increased slightly since 1895, with the exception of a slowed advance between approximately 1972 and 1984. The short-lived closure events in 1986 and 2002 were not initiated by perturbations in ice velocity or environmental forcings, but were likely due to fluctuations in sedimentation patterns at the terminus. This study points to the significance of a coupled system where short-term velocity fluctuations and morainal shoal development control tidewater glacier terminus position.

  1. Glaciological and marine geological controls on terminus dynamics of Hubbard Glacier, southeast Alaska

    NASA Astrophysics Data System (ADS)

    Stearns, L. A.; Hamilton, G. S.; van der Veen, C. J.; Finnegan, D. C.; O'Neel, S.; Scheick, J. B.; Lawson, D. E.

    2015-06-01

    Hubbard Glacier, located in southeast Alaska, is the world's largest nonpolar tidewater glacier. It has been steadily advancing since it was first mapped in 1895; occasionally, the advance creates an ice or sediment dam that blocks a tributary fjord (Russell Fiord). The sustained advance raises the probability of long-term closure in the near future, which will strongly impact the ecosystem of Russell Fiord and the nearby community of Yakutat. Here, we examine a 43 year record of flow speeds and terminus position to understand the large-scale dynamics of Hubbard Glacier. Our long-term record shows that the rate of terminus advance has increased slightly since 1895, with the exception of a slowed advance between approximately 1972 and 1984. The short-lived closure events in 1986 and 2002 were not initiated by perturbations in ice velocity or environmental forcings but were likely due to fluctuations in sedimentation patterns at the terminus. This study points to the significance of a coupled system where short-term velocity fluctuations and morainal shoal development control tidewater glacier terminus position.

  2. Air temperature and humidity diversity in the Hornsund fjord area (Spitsbergen) in the period 1 July 2014 - 30 June 2015

    NASA Astrophysics Data System (ADS)

    Przybylak, Rajmund; Araźny, Andrzej; Wyszyński, Przemysław; Budzik, Tomasz; Wawrzyniak, Tomasz

    2016-04-01

    The article presents preliminary results of studies into the spatial diversity of air temperature and relative humidity (overground layer, 2 m a.g.l.) in the area of the Hornsund fjord (S Spitsbergen, approx. 77°N), based on data collected between 1 July 2014 and 30 June 2015. The Hornsund fjord runs latitudinal along approx. 40 km and its average width is about 10 km. Numerous glaciers flow into the fjord and the mountain ridges around it often exceed 700 m a.s.l. Data series obtained from 11 sites equipped with automatic weather stations (Vaisala, Campbell, Davis) or HOBO temperature and humidity sensors were used. Two sites (Hornsund HOR and the Hans Glacier HG4) have been operating for years, whereas 9 new ones (Bogstranda BOG, Fugleberget FUG, Gnålodden GNA, Gåshamnoyra GAS, Hyttevika HYT, Lisbetdalen LIS, Ostrogradskijfjella OST, Treskelodden TRE and Wilczekodden WIL) were established within the Polish-Norwegian AWAKE-2 project. Three of the sites (BOG, GAS and OST) were damaged by polar bears, hence their measurement series are shorter. A substantial spatial diversity was found in the air temperature and relative humidity in the area, mostly influenced by elevation, type of surface and distance from the Greenland Sea's open water. During the year (July 2014 - June 2015), the areas of HYT (-1.1°C) and WIL (-1.9°C) were the warmest. Both sites are located on the west coast of the fjord. The HYT demonstrates the most favourable temperature conditions, being orographically sheltered from the east and its cold and dry air masses. The coldest sites were the mountain-top site of FUG (-5.9°C) and the glacier-located HG4 (-4.3°C). The low temperature at FUG resulted from its elevation (568 m a.s.l.), whereas at HG4 (184 m a.s.l) the glaciated surface also added up to the result. In the analysed period, the annual course of air temperature in the area had a clear minimum in February, when the lowest mean monthly values ranged from -9.4°C at HYT to -15.1°C at

  3. Fjord circulation and hydrographic structure associated with a rapidly-retreating glacier in the Patagonian Ice Fields

    NASA Astrophysics Data System (ADS)

    Moffat, C. F.

    2013-12-01

    Understanding the structure of buoyant plumes originating from melting glaciers and their interaction with the hydrographic structure and circulation of the surrounding ocean is key to elucidating the role of the ocean in modulating freshwater loss from the continents and to appropriately estimate present and future sea-level rise. Here, hydrographic and current velocity surveys are used to study the freshwater outflow in a fjord adjacent to Jorge Montt, an until recently rapidly (1 km/year) retreating glacier in the southern Patagonian Ice Fields. Surveys were conducted in the Summer of 2010 to 2012, Winter of 2011 and Fall 2012 to provide constraints on seasonal-scale changes. Montt fjord is approximately 20 km long, and is composed of a deep, proximal (to the ice) sub-basin of 350 m maximum depth and a shallower, distal sub-basin of around 100 m depth. Exchange with the 120-km long Baker Channel, the main conduit of exchange for the fjord with the South Eastern Pacific is severely constrained by a v-shaped, 45-m deep sill. During Summer, the freshwater outflow from the glacier mixes with the deep oceanic water found in the fjord to form a buoyant plume. This plume splits into a branch that reaches the surface and forms a relatively thick (10-20 m) brackish layer with salinities of 5 or less, and at least one subsurface branch that forms a horizontally coherent lateral intrusion found everywhere in the deep sub-basin. Results from using a thermodynamical melting model in combination with a linear mixing model suggest that the meltwater in the plume is dominated by subsurface runoff (10 %) with a smaller proportion of submarine melt (1-3 %). The fraction of subsurface runoff is higher in the top 100 m and it increases monotonically towards the surface, while subsurface melting also has a subsurface concentration maximum between 100 and 150 m. Velocity measurements show flow away from the glacier at the surface layer (top 10-20 m) and also at mid-depth, below the

  4. Dynamic response to strike-slip tectonic control on the deposition and evolution of the Baranof Fan, Gulf of Alaska

    USGS Publications Warehouse

    Walton, Maureen A. L.; Gulick, Sean P. S.; Reece, Robert S.; Barth, Ginger A.; Christeson, Gail L.; VanAvendonk, Harm J.

    2014-01-01

    The Baranof Fan is one of three large deep-sea fans in the Gulf of Alaska, and is a key component in understanding large-scale erosion and sedimentation patterns for southeast Alaska and western Canada. We integrate new and existing seismic reflection profiles to provide new constraints on the Baranof Fan area, geometry, volume, and channel development. We estimate the fan’s area and total sediment volume to be ∼323,000 km2 and ∼301,000 km3, respectively, making it among the largest deep-sea fans in the world. We show that the Baranof Fan consists of channel-levee deposits from at least three distinct aggradational channel systems: the currently active Horizon and Mukluk channels, and the waning system we call the Baranof channel. The oldest sedimentary deposits are in the northern fan, and the youngest deposits at the fan’s southern extent; in addition, the channels seem to avulse southward consistently through time. We suggest that Baranof Fan sediment is sourced from the Coast Mountains in southeastern Alaska, transported offshore most recently via fjord to glacial sea valley conduits. Because of the translation of the Pacific plate northwest past sediment sources on the North American plate along the Queen Charlotte strike-slip fault, we suggest that new channel formation, channel beheadings, and southward-migrating channel avulsions have been influenced by regional tectonics. Using a simplified tectonic reconstruction assuming a constant Pacific plate motion of 4.4 cm/yr, we estimate that Baranof Fan deposition initiated ca. 7 Ma.

  5. Minority Women's Health: American Indians/Alaska Natives

    MedlinePlus

    ... Health > American Indians/Alaska Natives Minority Women's Health American Indians/Alaska Natives Related information How to Talk to ... disease. Return to top Health conditions common in American Indian and Alaska Native women Accidents Alcoholism and drug ...

  6. Direct measurements of diapycnal mixing in a fjord reach—Puget Sound's Main Basin

    NASA Astrophysics Data System (ADS)

    Mickett, J. B.; Gregg, M. C.; Seim, H. E.

    2004-04-01

    In the spring of 1988, time series of microstructure and ADCP current profiles were collected at four locations in the North Main Basin of Puget Sound, Washington. Depth and time averages of diapycnal diffusivity < overlineK ρ> at the four stations ( 1.8-67.0×10 -4 m2 s-1) were one to three decades above typical open-ocean thermocline levels. The buoyancy frequency-squared N2 was near open-ocean levels, but unlike the open-ocean where N2≳ S2, finescale shear-squared S2 was three to six times N2 over significant portions of the water column at two of the stations. The time and space mean of all measurements ( < overlineK ρ>=3.6×10 -3 m2 s-1) is close to inferred vertical eddy diffusivity from a primitive equation model for Puget Sound ( K z=3×10 -3 m2 s-1) (J. Geophys. Res. 96 (1991) 16779). Large time and space variability of K ρ was found, with differences of inter-station, depth-time means over one decade. A simple scaling argument using the observed K ρ suggests significant exchange of mass between the layers of the subtidal flow over the basin's residence time. Additionally, measurements show that local mixing may be comparable to volume-weighted sill mixing in modifying the Main Basin's stratification. Both are contrary to the "advective reach" simplification of fjord dynamics. The mixing levels were dominated by the passage of a mid-depth, southward-flowing density intrusion and what we interpret as a strongly advected, non-linear internal tide. These mechanisms elevated profile-averaged K ρ by more than 10 times background levels, with sustained patches of K ρ≥1×10 -2 m2 s-1. Critical 8-m gradient Richardson numbers ( Ri8<0.25) matching regions of overturns (>20 m) and strong turbulence suggest that shear instabilities dominated the turbulence production, though there was support for double-diffusive convection in the warm core of the density intrusion.

  7. Morphodynamics and Sedimentology of a Falling Stage Sandy Fjord Delta, Goose River, Labrador

    NASA Astrophysics Data System (ADS)

    Slingerland, R.; Edmonds, D. A.; Parsons, D. R.; Best, J. L.; Royce, J.; Burpee, A.; Cederberg, J.; Caldwell, R.; Nijhuis, A.; McGuffin, A.

    2012-12-01

    Sediment size and degree of cohesion are thought to exert a strong control on the morphodynamic processes, planform shape and clinoform stratigraphy of deltas. To test model predictions concerning these two parameters, we present a morphometric and stratigraphic analysis of a sandy delta formed where the Goose River flows into Goose Bay at the western end of Lake Melville, Labrador. Goose River delta sediments consist of arkosic, heavy-mineral-rich sand (D50 = 225 to 600 microns) with very little silt and clay, placing this delta at the coarser-grained, non-cohesive end of the spectrum. The delta started to form approx. 7000 years ago as the Laurentide ice sheet retreated and post-glacial rebound created a relative base level fall of approximately 4 mm/yr. The current tidal range in Goose Bay averages 0.5 m, and the average wave height is negligible. Results from our 2012 field season show that the delta planform consists of two moribund lobes at elevations of ~ 5 m and ~ 2 m and a presently active delta at sea level. Aerial photography from 1951 to 2012 show there has been surprisingly little progradation despite active channel change at the six-month timescale and an assumed base level fall of 244 mm during that period. A topographic section along a dipline consists of three treads and two clinoform risers. The bottomset tread is a virtually featureless fjord bottom at ~35 m from which a first clinoform rises to a second tread at ~-15 m. The second tread is a sandy platform onto which an upper clinoform downlaps. This upper sandy clinoform ranges in dip from 9 to 17 dg. and passes into the topset at an elevation of ~ -1 m. The topset consists of braid-like trapezoidal unit bars that in GPR show little evidence of wave, alongshore current, or ice reworking, even though they are submerged at higher high tides. The planform, bar geometries and facies, and clinoform dips and dip-directions are remarkably consistent with model predictions from Delft3d.

  8. Shallow Sub-Permafrost Groundwater Systems In A Buried Fjord: Taylor Valley, Antarctica

    NASA Astrophysics Data System (ADS)

    Foley, N.; Tulaczyk, S. M.; Auken, E.; Mikucki, J.

    2014-12-01

    The McMurdo Dry Valleys (MDV), Antarctica, represent a unique geologic setting where permanent lakes, ephemeral streams, and subglacial waters influence surface hydrology in a cold polar desert. Past research suggested that the MDV are underlain by several hundreds of meters of permafrost. Here, we present data collected from an Airborne EM (AEM) resistivity sensor flown over the MDV during the 2011-12 austral summer. A focus of our survey was over the Taylor Glacier where saline, iron-rich subglacial fluid releases at the glacier snout at a feature known as Blood Falls, and over Taylor Valley, where a series of isolated lakes lie between Taylor Glacier and the Ross Sea. Our data show that in Taylor Valley there are extensive areas of low resistivity, interpreted as hypersaline brines, beneath a relatively thin layer of high resistivity material, interpreted as dry- or ice-cemented permafrost. These hypersaline brines remain liquid at temperatures well below 0°C due to their salinity. They appear to be contained within the sedimentary fill deposited in Taylor Valley when it was still a fjord. This brine system continues up valley and has a subglacial extension beneath Taylor Glacier, where it may provide the source that feeds Blood Falls. By categorizing the resistivity measurements according to surficial land cover, we are able to distinguish between ice, permafrost, lake water, and seawater based on characteristic resistivity distributions. Furthermore, this technique shows that areas of surface permafrost become increasingly conductive (brine-filled) with depth, whereas the large lakes exhibit taliks that extend through the entire thickness of the permafrost. The subsurface brines represent a large, unstudied and potentially connected hydrogeologic system, in which subsurface flows may help transfer water and nutrients between lakes in the MDV and into the Ross Sea. Such a system is a potential habitat for extremophile life, similar to that already detected in

  9. Developing a postglacial rockfall chronology in the mountainous fjord landscape of western Norway

    NASA Astrophysics Data System (ADS)

    Laute, Katja; Beylich, Achim A.; Winkler, Stefan

    2015-04-01

    Large areas of glacially sculpted mountain landscapes worldwide exhibit a high spatial density of postglacial rockfalls and rock-slope failures. However, the temporal patterns of rock-slope failure frequencies after Deglaciation are still fairly unknown. The mountainous fjord landscape in western Norway represents a suitable study area as it exhibits a high number of rockfalls and rock-slope failures within a region with a well known Deglaciation history. Two steep, parabolic-shaped and glacier-connected neighbouring drainage basins, Erdalen (79.5 km2) and Bødalen (60.1 km2), located on the western side of the Jostedalsbreen ice cap in western Norway are selected as study areas. The focus of this study is on (i) the temporal reconstruction of rockfalls and rock-slope failures within the two defined and nearly lithologically homogenous study areas and (ii) the identification and explanation of possible triggering and controlling factors of the investigated rock-slope failures. First investigations have started by applying Schmidt-hammer exposure-age dating (SHD) at seven larger rockfall deposits as well as at five moraines of known age within both study areas. During the sampling 50 to 100 impacts using a mechanical Proceq N-type instrument were taken from the surface of 5 to 50 single rockfall boulders located at the outer margin of the rockfall deposits. In order to avoid sampling of more recent rockfalls or redistributed debris material the sampling strategy selected preferred a larger number of individual boulders sampled with few impacts over sampling just a small number of boulders with a high number of multiple impacts. First results show that the mean rebound (R-) values measured at the seven rockfall deposits fall into recognizably different age categories. Based on the SHD measurements obtained from the moraines of known age, the determined rockfall age categories are situated between the Preboral and Little Ice Age period. The chronology and possible

  10. Warming of waters in an East Greenland fjord prior to glacier retreat: mechanisms and connection to large-scale atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Christoffersen, P.; Mugford, R. I.; Heywood, K. J.; Joughin, I.; Dowdeswell, J. A.; Syvitski, J. P. M.; Luckman, A.; Benham, T. J.

    2011-09-01

    Hydrographic data acquired in Kangerdlugssuaq Fjord and adjacent seas in 1993 and 2004 are used together with reanalysis from the NEMO ocean modelling framework to elucidate water-mass change and ice-ocean-atmosphere interactions in East Greenland. The hydrographic data show that the fjord contains warm subtropical waters and that fjord waters in 2004 were considerably warmer than in 1993. The ocean reanalysis shows that the warm properties of fjord waters in 2004 are related to a major peak in oceanic shoreward heat flux into a cross-shelf trough on the outer continental shelf. The heat flux into this trough varies according to seasonal exchanges with the atmosphere as well as from deep seasonal intrusions of subtropical waters. Both mechanisms contribute to high (low) shoreward heat flux when winds from the northeast are weak (strong). The combined effect of surface heating and inflow of subtropical waters is seen in the hydrographic data, which were collected after periods when along-shore coastal winds from the north were strong (1993) and weak (2004). The latter data were furthermore acquired during the early phase of a prolonged retreat of Kangerdlugssuaq Glacier. We show that coastal winds vary according to the pressure gradient defined by a semi-permanent atmospheric high-pressure system over Greenland and a persistent atmospheric low situated near Iceland. The magnitude of this pressure gradient is controlled by longitudinal variability in the position of the Icelandic Low.

  11. Interplay between filter-feeding zoobenthos and hydrodynamics in the shallow Odense Fjord (Denmark) - Earlier and recent studies, perspectives and modelling

    NASA Astrophysics Data System (ADS)

    Riisgård, H. U.; Lassen, J.; Kortegaard, M.; Møller, L. F.; Friedrichs, M.; Jensen, M. H.; Larsen, P. S.

    2007-11-01

    The shallow Odense Fjord (Denmark) is characterized by a large biomass of filter-feeding polychaetes ( Nereis diversicolor), clams ( Mya arenaria), cockles ( Cerastoderma glaucum), and amphipods ( Corophium volutator). The present paper summarizes studies on zoobenthic filter-feeding in Odense Fjord from the last 10 years. The general principles discovered are extracted and compared to available tools for modelling of the primary characteristics of interplay between benthic filter-feeders and hydrodynamics. Earlier works have been supplemented with data from a recent field study conducted in the shallow inner part of the fjord. Based on data from this study site, the reduction in phytoplankton for fully mixed and incompletely mixed flows has been modelled. It was found that fully mixed flow results in a potential half-life for phytoplankton of only 1.3 h, whereas for the incompletely mixed water the half-life is 2.7 times longer. The field measurements clearly demonstrate the presence of a strong interplay between filter-feeders and hydrodynamics, but although a certain grazing impact is evident from vertical chlorophyll a profiles with often strongly reduced near-bottom concentrations it is not straightforward to identify and model even the main bio-physical processes that prevent the dense populations of filter-feeders to completely control the phytoplankton biomass in Odense Fjord.

  12. A 100-year record of changes in water renewal rate in Sermilik fjord and its influence on calving of Helheim glacier, southeast Greenland

    NASA Astrophysics Data System (ADS)

    Andresen, Camilla S.; Schmidt, Sabine; Seidenkrantz, Marit-Solveig; Straneo, Fiammetta; Grycel, Aleksandra; Hass, Christian H.; Henrik Kjær, Kurt; Nørgaard-Pedersen, Niels; Dyke, Laurence M.; Olsen, Jesper; Kuijpers, Antoon

    2014-08-01

    Here we present a 100 year long proxy record for the renewal rate of the subsurface ocean waters in Sermilik Fjord at the edge of Helheim Glacier, based on investigations of two sediment cores (ER11-24 and ER11-25) obtained from the head of the fjord. By calculating the mean sortable silt (SSbar) in current-sorted melt water plume sediments we find that episodes of increased water renewal rates lasting 3-5 years coincide with a positive North Atlantic Oscillation (NAO) index. This is not surprising as low pressure systems and northeasterly storms are observed more frequently along the east coast of Greenland during positive NAO years as a result of the northward shift in the North Atlantic storm track. Previous studies of sediment cores obtained from the mid-region of the fjord showed that Helheim Glacier destabilization coincides with a negative NAO index. Therefore we conclude that inter-annual variability in storm-induced flushing of Sermilik Fjord and thus the water renewal rate towards the glacier margin is not the controlling factor for inter-annual variability in Helheim Glacier destabilization. Such knowledge may have implications on predictive model studies of ice-ocean interactions and glacier behavior.

  13. Forestry timber typing. Tanana demonstration project, Alaska ASVT. [Alaska

    NASA Technical Reports Server (NTRS)

    Morrissey, L. A.; Ambrosia, V. G.

    1982-01-01

    The feasibility of using LANDSAT digital data in conjunction with topographic data to delineate commercial forests by stand size and crown closure in the Tanana River basin of Alaska was tested. A modified clustering approach using two LANDSAT dates to generate an initial forest type classification was then refined with topographic data. To further demonstrate the ability of remotely sensed data in a fire protection planning framework, the timber type data were subsequently integrated with terrain information to generate a fire hazard map of the study area. This map provides valuable assistance in initial attack planning, determining equipment accessibility, and fire growth modeling. The resulting data sets were incorporated into the Alaska Department of Natural Resources geographic information system for subsequent utilization.

  14. Slope stability, triggering factors and threshold conditions. Study of debris flow activity in the Reyðarfjörður fjord, eastern Iceland.

    NASA Astrophysics Data System (ADS)

    Margeirsson, Guðbjörn; Sæmundsson, Þorsteinn; Norðdahl, Hreggviður

    2016-04-01

    Precipitation is one of the main triggering factor for debris flow activity in Eastern Iceland, but the amount needed, duration and the rainfall and its intensity to trigger the flow (e.g. the threshold condition) can vary considerably between areas. There are a few factors that have to be taken into account to determine the threshold condition and slope stability between areas, such as the slope angle and aspect, type and thickness of loose material, vegetation cover and gully distribution. Weather factors such as air and soil temperature, wind speed and wind direction is also crucial. The study area is located in the Reyðarfjörður fjord, one of the longest fjords on the east coast of Iceland. It is a 30 km long glacially eroded fjord, cut into the Tertiary bedrock. The bedrock is mostly made up of jointed basaltic lava flows, individual flows can vary in thickness from 2-30 m and usually separated by lithified sedimentary horizons often red in color. The slopes of the fjord are steep up to 900 m high, often consisting of nearly vertical cliffs, 60°-90°, in the upper parts of the slopes. The lower parts are covered with various glaciogenic landforms and consist of sediments and talus material. Several small hanging valleys and numerous small gullies and streams occur along the both sides of the fjord. The debris flow activity in the Reyðafjörður fjord is mostly constrained to the gullies and streams. Some activity has also been observed on the slopes between the gullies, but such activity is usually connected to extreme conditions, during or following heavy rain storms or a rainfall, especially of long duration. The aim of the study is to map the distribution of loose slope sediments in two areas inside the fjord, collect data about the known debris flow history, analyze various weather patterns which have contributed to these debris flows and understand how variables between the slopes react differently to different factors.

  15. Land-ocean gradient in haline stratification and its effects on plankton dynamics and trophic carbon fluxes in Chilean Patagonian fjords (47-50°S)

    NASA Astrophysics Data System (ADS)

    González, H. E.; Castro, L. R.; Daneri, G.; Iriarte, J. L.; Silva, N.; Tapia, F.; Teca, E.; Vargas, C. A.

    2013-12-01

    Patagonian fjord systems, and in particular the fjords and channels associated with the Baker/Pascua Rivers, are currently under conspicuous natural and anthropogenic perturbations. These systems display very high variability, where limnetic and oceanic features overlap generating strong vertical and horizontal physicochemical gradients. The CIMAR 14-Fiordos cruise was conducted in the Chilean fjords located between 47° and 50°S during the spring (October-November) of 2008. The main objectives were to study vertical and horizontal gradients in physical, chemical and biological characteristics of the water column, and to assess plankton dynamics and trophic carbon fluxes in the fjords and channels of central-south Patagonia. The water column was strongly stratified, with a pycnocline at ca. 20 m depth separating a surface layer of silicic acid-rich freshwater discharged by rivers, from the underlying nitrate- and orthophosphate-rich Subantarctic waters. The outflows from the Baker and Pascua Rivers, which range annually between 500 and 1500 m3 s-1, generate the strong land-ocean gradient in salinity (1-32 psu) and inorganic nutrient concentrations (2-8 and 2-24 μM in nitrate and silicic-acid, respectively) we observed along the Baker Fjord. The POC:chl-a ratio fluctuated from 1087 near the fjord’s head to 175 at its oceanic end in the Penas Gulf. This change was mainly due to an increase in diatom dominance and a concurrent decrease in allochthonous POC towards the ocean. Depth-integrated net primary production (NPP) and bacterial secondary production (BSP) fluctuated between 49 and 1215 and 36 and 150 mg C m-2 d-1, respectively, with higher rates in oceanic waters. At a time series station located close to the Baker River mouth, the average NPP was lower (average 360 mg C m-2 d-1) than at more oceanic stations (average 1063 mg C m-2 d-1), and numerically dominated (45%) by the picoplankton (<2 μm) and nanoplankton (2-20 μm) size fractions. The high average

  16. Glacio-tectonic thrust and deformation structures in the Vejle Fjord, Denmark revealed by high-resolution subbottom-profile data

    NASA Astrophysics Data System (ADS)

    Andresen, Katrine Juul; Boldreel, Lars Ole; Bak Wahlgreen, Katrine; Seidenkrantz, Marit-Solveig; Røy, Hans; Nørmark, Egon; Brandbyge Ernstsen, Verner

    2016-04-01

    Surface geomorphological features and partial cliff exposures up till now represent the predominant source of information of glaciation related deformation in Denmark. In this study we apply high-resolution marine reflection seismic data from the Vejle Fjord area, supported by gravity and Rumohr coring, to document intense glacio-tectonic deformation in the shallow subsurface of Denmark. The subbottom profiler seismic data have a peak frequency around 13 kHz and a vertical resolution in the order of 10-20 cm. The data reveal several variations of glacio-tectonic deformation structures, primarily observed near the edges of the fjord where coarse-grained and sandy deposits are present. These sediments allows for an exceptionally good and high-resolution imaging of the marine shallow subsurface. Within the central regions of the fjord, widespread shallow gas accumulations probably generated from biodegradation of post glacial organic-rich fine-grained marine gytja and clay deposits, effectively blank and absorb the seismic signal. This leads to a very poor imaging of the subsurface within the deeper parts of the fjord. Glacio-tectonic deformation is observed at both the northern and southern edge of the fjord. To the north, the deformation is expressed by complex internal reflection patterns within discrete sedimentary units including faults and smaller thrust-structures and associated small-scale folding. Channel incisions and clear reflection relations (i.e. truncations, onlaps and downlaps) reveal more decollement surfaces and furthermore constrain the timing of deformation. At least three episodes of deformation can be recognized at the northern edge of the fjord. To the south, a large thrusted fold belt (c. 3 km long and up to 10 m high) with faults, folds and thrust sheets is observed indicating severe deformation which most likely reflects ice progression from a southerly direction; for instance by the Young Baltic Ice Stream c. 19-17 ka. A thick and

  17. Alaska Native Participation in the Civilian Conservation Corps. Alaska Historical Commission Studies in History No. 206.

    ERIC Educational Resources Information Center

    Sorensen, Connor; And Others

    The report is a finding aid to the sources which document the 1937 federal policy decision mandating that 50% of the enrollees in the Civilian Conservation Corps (CCC) in Alaska must be Alaska Natives and provides a list of the Native CCC projects in Alaska. The finding aid section is organized according to the location of the collections and…

  18. Fisheries Education in Alaska. Conference Report. Alaska Sea Grant Report 82-4.

    ERIC Educational Resources Information Center

    Smoker, William W., Ed.

    This conference was an attempt to have the fishing industry join the state of Alaska in building fisheries education programs. Topics addressed in papers presented at the conference include: (1) fisheries as a part of life in Alaska, addressing participation of Alaska natives in commercial fisheries and national efforts; (2) the international…

  19. 76 FR 303 - Alaska: Adequacy of Alaska's Municipal Solid Waste Landfill Permit Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    ... AGENCY 40 CFR Parts 239 and 258 Alaska: Adequacy of Alaska's Municipal Solid Waste Landfill Permit... proposes to approve Alaska's modification of its approved Municipal Solid Waste Landfill (MSWLF) permit... Domenic Calabro, Office of Air, Waste, and Toxics, U.S. EPA, Region 10, 1200 Sixth Avenue, Suite...

  20. 76 FR 270 - Alaska: Adequacy of Alaska Municipal Solid Waste Landfill Permit Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    ...: I. Background On March 22, 2004, EPA issued a final rule (69 FR 13242) amending the Municipal Solid... AGENCY 40 CFR Parts 239 and 258 Alaska: Adequacy of Alaska Municipal Solid Waste Landfill Permit Program... modification to Alaska's approved Municipal Solid Waste Landfill (MSWLF) permit program. The...