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Sample records for bering sea

  1. Physical Controls on Ice Variability in the Bering Sea /

    OpenAIRE

    Li, Linghan

    2013-01-01

    This study primarily focuses on sea ice variability in the Bering Sea, and its thermodynamic and dynamic controls. First, the seasonal cycle of sea ice variability in the Bering Sea is studied using a global fine-resolution (1/10 -degree) fully-coupled ocean and sea ice model forced with reanalysis atmospheric forcing for 1980-1989. The ocean/ sea-ice model consists of the Los Alamos National Laboratory Parallel Ocean Program (POP) and the Los Alamos Sea Ice Model (CICE). The modeled seasonal...

  2. Ecosystem analysis in the southeastern Bering sea

    Science.gov (United States)

    Walsh, John J.; Peter McRoy, C.

    During a 7-year study of the food-chain dynamics of the outer and middle shelves of the southeastern Bering Sea, numerical models were developed to test ecological hypotheses posed at the event, seasonal, and annual scales of habitat variability. Interannual variations in year class strength of Alaska pollock between warm and cold years are attributed to an order of magnitude decline in prey availability during larval drift in cold years. In cold years delayed increases in seasonal abundance of copepod nauplii, the prey of these larval fish, are attributed to low temperature effects on crustacean metabolism rather than to changes in food availability (phytoplankton). Sinking diatoms, uneaten by the zooplankton in the water column during warm or cold years, are resuspended by wind events and advected seaward every 3 to 5 days during the spring. The ungrazed phytoplankton from the outer shelf are moved offshore and deposited on the adjacent slope. Because of the unusual width of the Bering shelf (˜500km) and a seasonal decline in the number of upwelling, favorable wind events, diatoms of the middle shelf are not exported. They are consumed instead by the benthos, with 10-fold larger infaunal biomass found here than on the outer shelf. An annual carbon budget for the middle shelf suggests consumption of all the primary production in this regime, compared to an apparent export of 48% of the outer shelf primary production to the continental slope.

  3. Cenozoic geodynamics of the Bering Sea region

    Science.gov (United States)

    Chekhovich, V. D.; Sukhov, A. N.; Sheremet, O. G.; Kononov, M. V.

    2012-05-01

    In the Early Cenozoic before origination of the Aleutian subduction zone 50-47 Ma ago, the northwestern (Asian) and northeastern (North American) parts of the continental framework of the Pacific Ocean were active continental margins. In the northwestern part, the island-arc situation, which arose in the Coniacian, remained with retention of the normal lateral series: continent-marginal sea-island arc-ocean. In the northeastern part, consumption of the oceanic crust beneath the southern margin of the continental Bering shelf also continued from the Late Cretaceous with the formation of the suprasubduction volcanic belt. The northwestern and northeastern parts of the Paleopacific were probably separated by a continuation of the Kula-Pacific Transform Fracture Zone. Change of the movement of the Pacific oceanic plates from the NNW to NW in the middle Eocene (50-47 Ma ago) was a cause of the origin of the Aleutian subduction zone and related Aleutian island arc. In the captured part of the Paleopacific (proto-Bering Sea), the ongoing displacement of North America relative to Eurasia in the middle-late Eocene gave rise to the formation of internal structural elements of the marginal sea: the imbricate nappe structure of the Shirshov Ridge and the island arc of the Bowers Ridge. The Late Cenozoic evolution was controlled by subduction beneath the Kamchatka margin and its convergence with the Kronotsky Terrane in the south. A similar convergence of the Koryak margin with the Goven Terrane occurred in the north. The Komandorsky minor oceanic basin opened in the back zone of this terrane. Paleotectonic reconstructions for 68-60, 56-52, 50-38, 30-15, and 15-6 Ma are presented.

  4. Bathymetry of the Aleutian and Bowers Basin, Bering Sea

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage contains bathymetric contours for Aleutian Basin and Bowers Basin east of the 1867 Convention Line in the southwestern Bering Sea. Geographic extent...

  5. Air-sea CO2 fluxes on the Bering Sea shelf

    Directory of Open Access Journals (Sweden)

    M. A. Jeffries

    2010-10-01

    Full Text Available There have been few previous studies of surface seawater CO2 partial pressure (pCO2 variability and air-sea CO2 gas exchange rates for the Bering Sea shelf which is the largest US coastal shelf sea. In 2008, spring and summertime observations were collected in the Bering Sea shelf as part of the Bering Sea Ecological Study (BEST. Our results indicate that the Bering Sea shelf was close to neutral in terms of CO2 sink-source status in springtime due to relatively small air-sea CO2 gradients (i.e., Δ pCO2 and sea-ice cover. However, by summertime, very low seawater pCO2 values were observed and much of the Bering Sea shelf became strongly undersaturated with respect to atmosphere CO2 concentrations. Thus the Bering Sea shelf transitions seasonally from mostly neutral conditions to a strong oceanic sink for atmospheric CO2 particularly in the "green belt" region of the Bering Sea. Ocean biological processes dominate the seasonal drawdown of seawater pCO2 for large areas of the Bering Sea shelf, with the effect partly countered by seasonal warming. In small areas of the Bering Sea shelf south of the Pribilof Islands and in the SE Bering Sea, seasonal warming is the dominant influence on seawater pCO2, shifting localized areas of the shelf from minor/neutral CO2 sink status to neutral/minor CO2 source status, in contrast to much of the Bering Sea shelf. We compute that the Bering Sea shelf CO2 sink in 2008 was 157 Tg C yr−1 (Tg = 1012 g C and a stronger sink for CO2 than previously demonstrated by other studies.

  6. Air-sea CO2 fluxes on the Bering Sea shelf

    Directory of Open Access Journals (Sweden)

    M. A. Jeffries

    2011-05-01

    Full Text Available There have been few previous studies of surface seawater CO2 partial pressure (pCO2 variability and air-sea CO2 gas exchange rates for the Bering Sea shelf. In 2008, spring and summertime observations were collected in the Bering Sea shelf as part of the Bering Sea Ecological Study (BEST. Our results indicate that the Bering Sea shelf was close to neutral in terms of CO2 sink-source status in springtime due to relatively small air-sea CO2 gradients (i.e., ΔpCO2 and sea-ice cover. However, by summertime, very low seawater pCO2 values were observed and much of the Bering Sea shelf became strongly undersaturated with respect to atmospheric CO2 concentrations. Thus the Bering Sea shelf transitions seasonally from mostly neutral conditions to a strong oceanic sink for atmospheric CO2 particularly in the "green belt" region of the Bering Sea where there are high rates of phytoplankton primary production (PPand net community production (NCP. Ocean biological processes dominate the seasonal drawdown of seawater pCO2 for large areas of the Bering Sea shelf, with the effect partly countered by seasonal warming. In small areas of the Bering Sea shelf south of the Pribilof Islands and in the SE Bering Sea, seasonal warming is the dominant influence on seawater pCO2, shifting localized areas of the shelf from minor/neutral CO2 sink status to neutral/minor CO2 source status, in contrast to much of the Bering Sea shelf. Overall, we compute that the Bering Sea shelf CO2 sink in 2008 was 157 ± 35 Tg C yr−1 (Tg = 1012 g C and thus a strong sink for CO2.

  7. Modeling the ocean circulation in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    HU Haoguo; WANG Jia

    2008-01-01

    With parameterized wave mixing, the circulation and the tidal current in the Bering Sea were simulated simultaneously using the three-dimensional Princeton Ocean Model. The simulated circulation pattern in the deep basin is relatively stable,cyclonic, and has little seasonal change. The Bering Slope Current between 200-1000m isobaths was estimated to be 5 Sv in volume transport. The Kamchatka Current was estimated to be 20 Sv off the Kamchatka Peninsula. The Bering shelf circulations vary with season, driven mainly by wind. These features are consistent with historical estimates. A counter current was captured flowing southeastward approximately along the 200 m isobath of the Bering Slope, opposite to the northwestward Bering Slope Current, which needs to be validated by observations. An upwelling current is located in the shelf break (120-1000 m) area, which may imply the vertical advection of nutrients for supporting the Bering Sea Green Belt seasonal plankton blooms in the breakslope area. The Bering Slope Current is located in a downwelling area.

  8. 50 CFR Figure 1 to Part 679 - Bering Sea and Aleutian Islands Statistical and Reporting Areas

    Science.gov (United States)

    2010-10-01

    ... THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Fig. 1 Figure 1 to Part 679—Bering Sea and Aleutian... economic zone as depicted on the current edition of NOAA chart INT 813 Bering Sea (Southern Part). Note:...

  9. The Northern Bering Sea: An Arctic Ecosystem in Change

    Science.gov (United States)

    Grebmeier, J. M.; Cooper, L. W.

    2004-12-01

    Arctic systems can be rich and diverse habitats for marine life in spite of the extreme cold environment. Benthic faunal populations and associated biogeochemical cycling processes are influenced by sea-ice extent, seawater hydrography (nutrients, salinity, temperature, currents), and water column production. Benthic organisms on the Arctic shelves and margins are long-term integrators of overlying water column processes. Because these organisms have adapted to living at cold extremes, it is reasonable to expect that these communities will be among the most susceptible to climate warming. Recent observations show that Arctic sea ice in the North American Arctic is melting and retreating northward earlier in the season and the timing of these events can have dramatic impacts on the biological system. Changes in overlying primary production, pelagic-benthic coupling, and benthic production and community structure can have cascading effects to higher trophic levels, particularly benthic feeders such as walruses, gray whales, and diving seaducks. Recent indicators of contemporary Arctic change in the northern Bering Sea include seawater warming and reduction in ice extent that coincide with our time-series studies of benthic clam population declines in the shallow northern Bering shelf in the 1990's. In addition, declines in benthic amphipod populations have also likely influenced the movement of feeding gray whales to areas north of Bering Strait during this same time period. Finally a potential consequence of seawater warming and reduced ice extent in the northern Bering Sea could be the northward movement of bottom feeding fish currently in the southern Bering Sea that prey on benthic fauna. This would increase the feeding pressure on the benthic prey base and enhance competition for this food source for benthic-feeding marine mammals and seabirds. This presentation will outline recent biological changes observed in the northern Bering Sea ecosystem as documented in

  10. Relationship between Hadley circulation and sea ice extent in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    ZHOU BoTao; WANG HuiJun

    2008-01-01

    The linkage between Hadley circulation (HC) and sea ice extent in the Bering Sea during March-April is investigated through an analysis of observed data in this research. It is found that HC is negatively correlated to the sea ice extent in the Bering Sea, namely, strong (weak) HC is corresponding to less (more) sea ice in the Bering Sea. The present study also addresses the large-scale atmospheric general circulation changes underlying the relationship between HC and sea ice in the Bering Sea. It follows that a positive phase of HC corresponds to westward located Aleutian low, anomalous southerlies over the eastern North Pacific and higher temperature in the Bering Sea, providing unfavorable atmospheric and thermal conditions for the sea ice forming, and thus sea ice extent in the Bering Sea is decreased, and vice versa. In addition, it is further identified that East Asian-North Pacific-North America telecon-nection may play an important role in linking HC and changes of atmospheric circulations as well as sea ice in the Bering Sea.

  11. Bathymetric Map of the Bering/Chukchi Sea

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Two bathymetric maps were developed by the U.S. Geological Survey, one for the Chukchi Sea and Arctic Ocean, and one for the Aleutian Trench and Bering Sea. The 2...

  12. 78 FR 76245 - Fisheries of the Exclusive Economic Zone Off Alaska; Greenland Turbot in the Bering Sea Subarea...

    Science.gov (United States)

    2013-12-17

    ... and 2014 harvest specifications for groundfish in the BSAI (78 FR 13813, March 1, 2013). In accordance... Economic Zone Off Alaska; Greenland Turbot in the Bering Sea Subarea of the Bering Sea and Aleutian Islands... for Greenland turbot in the Bering Sea subarea of the Bering Sea and Aleutian Islands management...

  13. 78 FR 24361 - Fisheries of the Exclusive Economic Zone Off Alaska; Greenland Turbot in the Bering Sea Subarea...

    Science.gov (United States)

    2013-04-25

    ... and 2014 harvest specifications for groundfish in the BSAI (78 FR 13813, March 1, 2013). In accordance... Economic Zone Off Alaska; Greenland Turbot in the Bering Sea Subarea of the Bering Sea and Aleutian Islands... for Greenland turbot in the Bering Sea subarea of the Bering Sea and Aleutian Islands management...

  14. Distributions and air-sea fluxes of CO2 in the summer Bering Sea

    Institute of Scientific and Technical Information of China (English)

    CHEN Liqi; GAO Zhongyong; SUN Heng; CHEN Baoshan; CAI Wei-jun

    2014-01-01

    The 3rd Chinese National Arctic Research Expedition (CHINARE-Arctic III) was carried out from July to Sep-tember in 2008. The partial pressure of CO2 (pCO2) in the atmosphere and in surface seawater were deter-mined in the Bering Sea during July 11-27, 2008, and a large number of seawater samples were taken for total alkalinity (TA) and total dissolved inorganic carbon (DIC) analysis. The distributions of CO2 parameters in the Bering Sea and their controlling factors were discussed. The pCO2 values in surface seawater presented a drastic variation from 148 to 563μatm (1μatm=1.013 25×10-1 Pa ). The lowest pCO2 values were observed near the Bering Sea shelf break while the highest pCO2 existed at the western Bering Strait. The Bering Sea generally acts as a net sink for atmospheric CO2 in summer. The air-sea CO2 fluxes in the Bering Sea shelf, slope, and basin were estimated at-9.4,-16.3, and-5.1 mmol/(m2·d), respectively. The annual uptake of CO2 was about 34 Tg C in the Bering Sea.

  15. Sea-level variation/change and thermal contribution in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    ZUO Juncheng; ZHANG Jianli; DU Ling; LI Peiliang; LI Lei

    2005-01-01

    The long-term sea-level trend in the Bering Sea is obtained by the analysis of TOPEX/Poseidon altimeter data, including the data of two tide gauges. The averaged sea-level in the Bering Sea rises at a rate of 2.47 mm/a from 1992 to 2002. The mean sea-level is falling in the most part of the Bering Sea, especially in its central basin, and it is rising in the northeastern part of the Bering Sea. During the 1998/99 change, the sea-level anomaly differences exhibit a significant sea-level anomaly fall in the deep basin of the Bering Sea,which is roughly in the same position where a prominent SST fall exists. The maximal fall of sea-level is about 10 cm in the southwestern part of the Bering Sea, and the maximal fall of about 2℃ in the SST also appeared in the same region as the sea level did.The steric sea-level change due to temperature variations is discussed. The results are compared with the TOPEX/Poseidon altimeter data at the different spatial scales. It is indicated that the seasonal amplitude of the steric height is about 35% of the observed TOPEX/Poseidon amplitude, which is much smaller than the 83% in the mid-latitudes area. The systematic difference between the TOPEX/Poseidon data with the range of about 7.5 cm and the thermal contribution with the range of about 2.5 cm is about 5 cm. This indicates that the thermal effect on the sea level is not as important as the case in the mid-latitudes area. In the Bering Sea, the phase of the steric height leads the observed sea level by about three months.

  16. Distribution and abundance of decapod crustacean larvae in the southeastern Bering Sea with emphasis on commercial species. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, D.A.; Incze, L.S.; Wencker, D.L.; Armstrong, J.L.

    1981-01-01

    Contents include: Distribution and abundance of king crab larvae, Paralithodes camtschatica and P. platypus in the southeast Bering Sea; Distribution and abundance of the larvae of tanner crabs in the southeastern Bering Sea; Distribution and abundance of other brachyuran larvae in the southeastern Bering Sea with emphasis on Erimacrus isenbeckii; Distribution and abundance of shrimp larvae in the southeastern Bering Sea with emphasis on pandalid species; Distribution and abundance of hermit crabs (Paguridae) in the southeasternBering Sea; Possible oil impacts on decapod larbae in the southeastern Bering Sea with emphesis on the St. George Basin.

  17. 78 FR 54591 - Fisheries of the Exclusive Economic Zone Off Alaska; Greenland Turbot in the Bering Sea and...

    Science.gov (United States)

    2013-09-05

    ... under Sec. 679.20(d)(1)(iii) on May 1, 2013 (78 FR 24361, April 25, 2013). NMFS has determined that as... Economic Zone Off Alaska; Greenland Turbot in the Bering Sea and Aleutian Islands Management Area AGENCY... Greenland turbot in the Bering Sea subarea of the Bering Sea and Aleutian Islands Management Area...

  18. Progress report on field studies in the Aleutian Islands, Semidi Islands and Bering Sea, 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes work in the Aleutian Islands, Semidi Islands, and Bering Sea in support of work unit 953.10. Distribution and abundance of birds as seas work...

  19. Obsolete - AFSC/RACE/Eco-FOCI: 2010 Eastern Bering Sea Juvenile Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data collected on this cruise included the following: We conducted a juvenile fish and benthic fish prey survery in the eastern Bering Sea (61 3-meter beam trawls,...

  20. AFSC/ABL: 2006 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch of the 2006 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was...

  1. AFSC/ABL: 2007 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch of the 2007 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was...

  2. AFSC/ABL: 2009 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch of the 2009 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was...

  3. AFSC/ABL: 2011 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch from the 2011 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was...

  4. AFSC/ABL: 2005 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch of the 2005 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was...

  5. AFSC/ABL: 2008 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch of the 2008 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was...

  6. AFSC/ABL: 2012 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch from the 2012 Bering Sea walleye pollock (Gadus chalcogrammus) trawl fishery was...

  7. AFSC/RACE/MACE: Results of 2010 Pollock Acoustic-Trawl Survey Bering Sea- DY1006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 5 June and 7 August 2010 using...

  8. AFSC/RACE/MACE: Results of 2009 Pollock Acoustic-Trawl Survey Bering Sea- DY0909

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 9 June and 7 August 2009 using...

  9. AFSC/RACE/MACE: Results of 2012 Pollock Acoustic-Trawl Survey Bering Sea- DY1207

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) midwater abundance and distribution were assessed from Bristol Bay in the United States, to Cape...

  10. AFSC/ABL: 2010 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch of the 2010 Bering Sea groundfish trawl fishery was undertaken to determine the...

  11. AFSC/ABL: Eastern Bering Sea (EMA-BASIS) Zooplankton data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

  12. Particle sizes of Pliocene and Pleistocene core sediments from IODP Expedition 323 in the Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data compilation includes the results of grain size analyses of core sediment collected by IODP during Expedition 323 in the Bering Sea. One dataset is...

  13. AFSC/ABL: Chum salmon bycatch genetic stock identification 1994-1995 Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In some years, the Bering Sea trawl fishery incidentally harvests (bycatch) large numbers of chum salmon. Because chum salmon were declining in some western Alaska...

  14. AFSC/RACE/MACE: Results of 2014 Pollock Acoustic-Trawl Survey Bering Sea- DY1407

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Gadus chalcogrammus) midwater abundance and distribution were assessed from Bristol Bay in the United States, to Cape...

  15. AFSC/RACE/MACE: Results of 2007 Pollock Acoustic-Trawl Survey Bering Sea- DY0707

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Eastern Bering Sea shelf walleye pollock (Theragra chalcogramma) abundance and distribution in midwater were assessed between 2 June and 30 July 2007 using echo...

  16. AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon (TSG-thermosalinigraph data)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

  17. AFSC/RACE/GAP/Yeung: Eastern Bering Sea Essential Fish Habitat Benthic Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic samples were collected between 2009-2012 in the Bering Sea to study Essential Fish Habitat. Station locations were at or near fixed stations of the AFSC...

  18. AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon (Oceanography data)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

  19. AFSC FIT Pacific cod tagging data from the Bering Sea, 2002-2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from opportunistic tagging studies in the southest Bering Sea 2002-2003. Individually numbered loop spaghetti tags released during research cruises; all...

  20. Late Winter Population and Distribution of Spectacled Eiders (Somateria fischeri) in the Bering Sea

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — We conducted aerial surveys in the northern Bering Sea in late winter 1995, 1996 and 1997 to estimate the population of spectacled eiders (Somateria fischeri)...

  1. AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O....

  2. Foraminifera in surface sediments of the Bering and Chukchi Seas and their sedimentary environment

    Institute of Scientific and Technical Information of China (English)

    孟翊; 陈荣华; 郑玉龙

    2002-01-01

    Based on a quantitative analysis of foraminifera in 39 surface samples of the Bering and Chukchi Seas, the nearly absence of planktonic foraminifera in the surface sediments can be related to the low surface primary productivity and strong carbonate dissolution in the study area. It has been revealed that the surface primary productivity, and carbonate dissolution and properties of water masses related to the water depth mainly control the distribution of benthic foraminifera. The shelf of the Chukchi Sea is dominated by the Elphidium spp. Assemblage and Nonionella robusta assemblage with low forarniniferal abundance and diversity, which is controlled by the coastal water mass of the Arctic Ocean. The slope of the Bering Sea is dominated by the Uvigerina peregrina - Globobulimina affinis assemblage with abundant N. Robusta, and relatively high foraminiferal abundance and diversity, which is controlled by the intermediate and deep water masses of the Pacific Ocean. However, the Bering Sea has relatively shallow carbonate lysocline and compensation depth (CCD), at about 2 000 and 3 800 m, respectively.In addition, there exists Stetsonia arctica in the surface sediments of the upper slope in the Bering Sea,which is a typical deep-sea benthic foraminiferal species of the slope in the Arctic Ocean. This indicates that the deep water of the two seas beside the Bering Strait had ever exchanged.

  3. Oxygen isotopic composition and its application to the study of tracing oceanographical process in Bering Sea and Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    尹明端; 曾宪章; 曾文义; 吴世炎; 施纯坦

    2002-01-01

    In this paper, the 18O distribution of surface water from the central sea areas of the Bering Sea and the Chukchi Sea was studied. The δ18O value of surface water from the Bering Sea is averagely -0.5‰; the δ18O contents of the Chukchi Sea are distributionally lower in northeast and higher in southwest; the δ18O value at the margin of Canadian Basin is -2.8‰, and averagely -0.8‰ in the southern area of the Chukchi Sea. The δ18O vertical distribution in some deep water stations from the Chukchi Sea and the Bering Sea is also studied. In the southern margin of Canadian Basin, the δ18O value is -2‰ -3‰ for surface layer and rises to 0 at 100 m depth layer. In the Bering Sea, the δ18O is about -0.5‰ for surface layer and increases to 0 at the depth of 300 m. The NO tracer can reflect obviously three water masses vertically distributed in the central Bering Sea: the upper Bering water mass, the middle Bering water mass and the deep Pacific water mass. The distributive ranges of NO and temperature for the various water masses are T780 μmol/dm3 and T≥7℃, NO>650 μmol/dm3 for upper Bering water mass, T<4℃, 550Bering water mass, and T<4℃, 330sea bottom. Its isotopic characteristics are the same as the Atlantic water, showing that the sea water comes from the north Atlantic. The freshwater end-member of the Chukchi Sea in the survey period is also explored.

  4. 50 CFR Figure 20 to Part 679 - Steller sea lion conservation area (SCA) of the Bering Sea

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Steller sea lion conservation area (SCA) of the Bering Sea 20 Figure 20 to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Fig. 20 Figure 20 to Part 679—Steller sea lion conservation...

  5. 76 FR 71269 - Fisheries of the Exclusive Economic Zone Off Alaska; Greenland Turbot in the Bering Sea Subarea...

    Science.gov (United States)

    2011-11-17

    ... groundfish in the BSAI (76 FR 11139, March 1, 2011). The harvest specification for the 2011 Greenland turbot... 2011 and 2012 harvest specifications for groundfish of the BSAI (76 FR 11139, March 1, 2011). In... Economic Zone Off Alaska; Greenland Turbot in the Bering Sea Subarea of the Bering Sea and Aleutian...

  6. 78 FR 63951 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2013-10-25

    ... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management Area; Amendment 99 AGENCY: National... to the Fishery Management Plan for Groundfish of the Bering Sea and Aleutian Islands Management Area... older vessels with newer and more efficient vessels that are able to meet modern vessel safety...

  7. 76 FR 59924 - Fisheries of the Exclusive Economic Zone Off Alaska; Sharks in the Bering Sea and Aleutian...

    Science.gov (United States)

    2011-09-28

    ... Economic Zone Off Alaska; Sharks in the Bering Sea and Aleutian Islands Management Area AGENCY: National...: Temporary rule; closure. SUMMARY: NMFS is prohibiting retention of sharks in the Bering Sea and Aleutian... sharks in the BSAI has been reached. DATES: Effective 1200 hrs, Alaska local time (A.l.t.), September...

  8. 78 FR 57097 - Fisheries of the Exclusive Economic Zone Off Alaska; Sharks in the Bering Sea and Aleutian...

    Science.gov (United States)

    2013-09-17

    ... Economic Zone Off Alaska; Sharks in the Bering Sea and Aleutian Islands Management Area AGENCY: National...: Temporary rule; closure. SUMMARY: NMFS is prohibiting retention of sharks in the Bering Sea and Aleutian... sharks in the BSAI has been reached. DATES: Effective 1200 hrs, Alaska local time (A.l.t.), September...

  9. 77 FR 44216 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2012-07-27

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Cost Recovery Program AGENCY: National... recovery under the Bering Sea and Aleutian Islands Crab Rationalization Program. This action is intended to provide holders of crab allocations with the fee percentage for the 2012/2013 crab fishing year....

  10. 76 FR 43658 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-07-21

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Cost Recovery Program AGENCY: National... under the Bering Sea and Aleutian Islands Crab Rationalization Program. This action is intended to provide holders of crab allocations with the fee percentage for the 2011/2012 crab fishing year so...

  11. 75 FR 43147 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2010-07-23

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Cost Recovery Program AGENCY: National... under the Bering Sea and Aleutian Islands Crab Rationalization Program. This action is intended to provide holders of crab allocations with the fee percentage for the 2010/2011 crab fishing year so...

  12. 78 FR 17341 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-03-21

    ... regulations implementing the Crab Rationalization Program (CR Program) in 2005 (70 FR 10174, March 2, 2005... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab Rationalization Program AGENCY: National... to the Fishery Management Plan for Bering Sea/Aleutian Islands King and Tanner Crabs (FMP)....

  13. 78 FR 46577 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-08-01

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Cost Recovery Program AGENCY: National... under the Bering Sea and Aleutian Islands Crab Rationalization Program. This action is intended to provide holders of crab allocations with the fee percentage for the 2013/2014 crab fishing year so...

  14. 75 FR 37371 - Fisheries of the Exclusive Economic Zone Off Alaska; Fisheries of the Bering Sea Subarea

    Science.gov (United States)

    2010-06-29

    ... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-AY34 Fisheries of the Exclusive Economic Zone Off Alaska; Fisheries of the Bering Sea Subarea AGENCY: National Marine Fisheries Service... of the Northern Bering Sea Research Area to establish the Modified Gear Trawl Zone and to expand...

  15. 77 FR 44172 - Fisheries of the Exclusive Economic Zone Off Alaska; Squid in the Bering Sea and Aleutian Islands...

    Science.gov (United States)

    2012-07-27

    ... BSAI exclusive economic zone according to the Fishery Management Plan for Groundfish of the Bering Sea... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XC119 Fisheries of the Exclusive Economic Zone Off Alaska; Squid in the Bering Sea and Aleutian Islands Management Area AGENCY:...

  16. 76 FR 24404 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod in the Bering Sea and Aleutian...

    Science.gov (United States)

    2011-05-02

    ... BSAI exclusive economic zone according to the Fishery Management Plan for Groundfish of the Bering Sea... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XA405 Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod in the Bering Sea and Aleutian Islands Management Area...

  17. Toward development of the 4Dvar data assimilation system in the Bering Sea: reconstruction of the mean dynamic ocean topography

    Institute of Scientific and Technical Information of China (English)

    Gleb Panteleev; Dmitri Nechaev; Vladimir Luchin; Phyllis Stabeno; Nikolai Maximenko; Motoyoshi Ikeda

    2008-01-01

    The Bering Sea circulation is derived as a variational inverse of hydrographic profiles( temperature and salinity) , atmospheric climatologies and historical observation of ocean curents. The important result of this study is estimate of the mean climatological sea surface height (SSH) that can be used as a reference for satellite altimetry sea level anomaly data in the Bering Sea region. Numerical experiments reveal that, when combined with satellite altimetry, the obtained reference SSH effectively constrains a realistic reconstruction of the Amukta Pass circulation.

  18. [Distribution pattern of microphytoplankton in the Bering Sea during the summer of 2010].

    Science.gov (United States)

    Lin, Geng-Ming; Yang, Qing-Liang; Wang, Yu

    2013-09-01

    Based on the analysis of 70 water samples collected by the Chinese icebreaker Xuelong in the areas of 52 degrees 42.29'-65 degrees 30.23' N and 169 degrees 20.85' E-179 degrees 30.37' W in the Bering Sea during the Chinese Arctic Research Expedition on July 10-19, 2010, a total of 143 phytoplankton species were identified, including 95 diatom species belonging to 37 genera, 44 dinoflagellate species belonging to 15 genera, 2 Chlorophyta species belonging to 2 genera, 1 Euglenophyta belonging to 1 genus, and 1 Chrysophyta species belonging to 1 genus. The cluster analysis revealed that the phytoplankton in the study areas could be divided as oceanic and shallow water groups. The oceanic group found in the western North Pacific Ocean and the Bering Basin was dominated by the boreal oceanic species such as Neodenticula seminae and Chaetoceros atlanticus and the cosmopolitan species such as Thalassionema nitzschioides and Chaetoceros compressus, with the characteristics of low abundance and high evenness of diversified species. The shallow water group found in the continental shelf and slope of Bering Sea was mostly composed of the pan-arctic neritic species such as Thalassiosira nordenskioldi and Chaetoceros furcellatus and the cosmopolitan species such as Leptocylindrus danicus and Chaetoceros curvisetus, with the characteristics of low species diversity and evenness index due to the high abundance in certain species. The phytoplankton abundance in the surface water layer distributed unevenly among the stations, ranging from 950 to 192400 cells x L(-1) and with an average of 58722 cells x L(-1). Horizontally, the abundance distribution trend was decreased in the order of the Bering Sea shelf, the Bering Sea slope, the Bering Sea basin, and the western North Pacific Ocean. Vertically, the abundance was lower in surface layer and maximized in the thermocline, suggesting that the phytoplankton abundance in vertical distribution varied with the regional thermocline.

  19. Chemistry of Aerosols over Chukchi Sea and Bering Sea

    Institute of Scientific and Technical Information of China (English)

    朱赖民; 陈立奇; 杨绪林; 杜俊民; 张远辉

    2004-01-01

    The contents of elements in aerosols sampled during the First Chinese Arctic Research Expedition (CHINARE-1) show great differences from one element to another. Na, K,Ca, Mg, Al, F, and Cl are the major components in the aerosols, whose contents are larger than 30 ng/m3. The chemical elements whose contents vary between 0.1-30 ng/m3 are Br,Sr, Cr, Ni, and Zn. The chemical elements whose contents are close to or slightly higher than 0. 1 ng/m3 are Rb, Ba, Zr, Th, and Pb. The contents of As, Sb, W, Mo, Au, La, Ce, Nd,Sm, Eu, Tb, Yb, Lu, Sc, Co, Hf, Ta, and Cd are less than 0.1 ng/m3. The mass concentration data for the same element, as observed during CHINARE-1, are almost accordant, but much lower than what is observed in the China' s seas or the coasts of China. The enrichment factor and electron microscopic analyses and lead isotope tracing were used to distinguish their sources.Four groups of sources can be classified as follows: anthropogenic: As, Sb, W, F, Mo, Au,Cu, Pb, Cd, V; crustal: La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Fe, Sc, Cr, Co, Ba, Zr, Hf,Ta, Cs, Mn, Th, U; oceanic:Na, K, Ca, and Mg; and mixing: Rb, Sr, Ca, and Mg.

  20. Biogeochemical cycling in the Bering Sea over the onset of major Northern Hemisphere Glaciation

    Science.gov (United States)

    Swann, George E. A.; Snelling, Andrea M.; Pike, Jennifer

    2016-09-01

    The Bering Sea is one of the most biologically productive regions in the marine system and plays a key role in regulating the flow of waters to the Arctic Ocean and into the subarctic North Pacific Ocean. Cores from Integrated Ocean Drilling Program (IODP) Expedition 323 to the Bering Sea provide the first opportunity to obtain reconstructions from the region that extend back to the Pliocene. Previous research at Bowers Ridge, south Bering Sea, has revealed stable levels of siliceous productivity over the onset of major Northern Hemisphere Glaciation (NHG) (circa 2.85-2.73 Ma). However, diatom silica isotope records of oxygen (δ18Odiatom) and silicon (δ30Sidiatom) presented here demonstrate that this interval was associated with a progressive increase in the supply of silicic acid to the region, superimposed on shift to a more dynamic environment characterized by colder temperatures and increased sea ice. This concluded at 2.58 Ma with a sharp increase in diatom productivity, further increases in photic zone nutrient availability and a permanent shift to colder sea surface conditions. These transitions are suggested to reflect a gradually more intense nutrient leakage from the subarctic northwest Pacific Ocean, with increases in productivity further aided by increased sea ice- and wind-driven mixing in the Bering Sea. In suggesting a linkage in biogeochemical cycling between the south Bering Sea and subarctic Northwest Pacific Ocean, mainly via the Kamchatka Strait, this work highlights the need to consider the interconnectivity of these two systems when future reconstructions are carried out in the region.

  1. Genetic stock identification of immature chum salmon ( Oncorhynchus keta) in the western Bering Sea, 2004

    Science.gov (United States)

    Kang, Minho; Kim, Suam; Low, Loh-Lee

    2016-03-01

    Genetic stock identification studies have been widely applied to Pacific salmon species to estimate stock composition of complex mixed-stock fisheries. In a September-October 2004 survey, 739 chum salmon ( Oncorhynchus keta) specimens were collected from 23 stations in the western Bering Sea. We determined the genetic stock composition of immature chum salmon based on the previous mitochondria DNA baseline. Each regional estimate was computed based on the conditional maximum likelihood method using 1,000 bootstrap resampling and then pooled to the major regional groups: Korea - Japan - Primorie (KJP) / Russia (RU) / Northwest Alaska (NWA) / Alaska Peninsula - Southcentral Alaska - Southeast Alaska - British Columbia - Washington (ONA). The stock composition of immature chum salmon in the western Bering Sea was a mix of 0.424 KJP, 0.421 RU, 0.116 NWA, and 0.039 ONA stocks. During the study period, the contribution of Asian chum salmon stocks gradually changed from RU to KJP stock. In addition, North American populations from NWA and ONA were small but present near the vicinity of the Russian coast and the Commander Islands, suggesting that the study areas in the western Bering Sea were an important migration route for Pacific chum salmon originating both from Asia and North America during the months of September and October. These results make it possible to better understand the chum salmon stock composition of the mixed-stock fisheries in the western Bering Sea and the stock-specific distribution pattern of chum salmon on the high-seas.

  2. 75 FR 41123 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea Subarea

    Science.gov (United States)

    2010-07-15

    .... SUMMARY: NMFS issues a proposed rule that would implement Amendment 94 to the Fishery Management Plan for Groundfish of the Bering Sea and Aleutian Islands Management Area (FMP). Amendment 94, if approved, would... habitat near St. Matthew Island, and to allow for efficient flatfish harvest as the ] distribution...

  3. Sound velocity and related properties of seafloor sediments in the Bering Sea and Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    MENG Xiangmei; LI Guanbao; HAN Guozhong; KAN Guangming

    2015-01-01

    The Bering Sea shelf and Chukchi Sea shelf are believed to hold enormous oil and gas reserves which have attracted a lot of geophysical surveys. For the interpretation of acoustic geophysical survey results, sediment sound velocity is one of the main parameters. On seven sediment cores collected from the Bering Sea and Chukchi Sea during the 5th Chinese National Arctic Research Expedition, sound velocity measurements were made at 35, 50, 100, 135, 150, 174, 200, and 250 kHz using eight separate pairs of ultrasonic transducers. The measured sound velocities range from 1 425.1 m/s to 1 606.4 m/s and are dispersive with the degrees of dispersion from 2.2% to 4.0% over a frequency range of 35–250 kHz. After the sound velocity measurements, the measurements of selected geotechnical properties and the Scanning Electron Microscopic observation of microstructure were also made on the sediment cores. The results show that the seafloor sediments are composed of silty sand, sandy silt, coarse silt, clayey silt, sand-silt-clay and silty clay. Aggregate and diatom debris is found in the seafloor sediments. Through comparative analysis of microphotographs and geotechnical properties, it is assumed that the large pore spaces between aggregates and the intraparticulate porosity of diatom debris increase the porosity of the seafloor sediments, and affect other geotechnical properties. The correlation analysis of sound velocity and geotechnical properties shows that the correlation of sound velocity with porosity and wet bulk density is extreme significant, while the correlation of sound velocity with clay content, mean grain size and organic content is not significant. The regression equations between porosity, wet bulk density and sound velocity based on best-fit polynomial are given.

  4. Zooplankton data collected from THOMAS G. THOMPSON in Bering Sea; 01 April 1980 to 13 October 1981 (NODC Accession 9800133)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using zooplankton net casts in Bering Sea from THOMAS G. THOMPSON. Data were collected from 01 April 1980 to 13 October 1981 by...

  5. Acoustic-Trawl Survey of Walleye Pollock on the Eastern Bering Sea Shelf (DY1407, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment survey on the eastern Bering Sea...

  6. AFSC/REFM: Movement of Alaska skates (Bathyraja parmifera) in the Bering Sea , determined through conventional tagging

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains the results of a tagging study being conducted on the Alaska skate (Bathyraja parmifera) in the eastern Bering Sea. The purpose of the study...

  7. NPRB711 Quantification of unobserved injury and mortality of Bering Sea crabs due to encounters with trawls on the seafloor

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The potential for unobserved mortality of crabs encountering bottom trawls, but not captured, has long been a concern in the management of Bering Sea fisheries. We...

  8. AFSC/NMML: Passive acoustic sonobuoy recordings from Bering, Chukchi, and Beaufort Seas in Alaska, 2007-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has conducted passive acoustic monitoring in the Bering, Chukchi, and Western Beaufort Seas to determine...

  9. AFSC/NMML: Cetacean line-transect survey in the eastern Bering Sea shelf; 1999, 2000, 2002, and 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visual surveys for cetaceans were conducted on the eastern Bering Sea shelf along transect lines, in association with the AFSC.s echo integration trawl surveys for...

  10. AFSC/RACE/FBEP/Hurst: Contrasting coastal and shelf nursery habitats of Pacific cod in the southeastern Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is from a study examining the use of demersal and pelagic habitats in the southeast Bering Sea by age-0 Pacific cod, based on 4 years of demersal trawl...

  11. Ecosystem dynamics of the Pacific-influenced Northern Bering and Chukchi Seas in the Amerasian Arctic

    Science.gov (United States)

    Grebmeier, Jacqueline M.; Cooper, Lee W.; Feder, Howard M.; Sirenko, Boris I.

    2006-10-01

    The shallow continental shelves and slope of the Amerasian Arctic are strongly influenced by nutrient-rich Pacific waters advected over the shelves from the northern Bering Sea into the Arctic Ocean. These high-latitude shelf systems are highly productive both as the ice melts and during the open-water period. The duration and extent of seasonal sea ice, seawater temperature and water mass structure are critical controls on water column production, organic carbon cycling and pelagic-benthic coupling. Short food chains and shallow depths are characteristic of high productivity areas in this region, so changes in lower trophic levels can impact higher trophic organisms rapidly, including pelagic- and benthic-feeding marine mammals and seabirds. Subsistence harvesting of many of these animals is locally important for human consumption. The vulnerability of the ecosystem to environmental change is thought to be high, particularly as sea ice extent declines and seawater warms. In this review, we focus on ecosystem dynamics in the northern Bering and Chukchi Seas, with a more limited discussion of the adjoining Pacific-influenced eastern section of the East Siberian Sea and the western section of the Beaufort Sea. Both primary and secondary production are enhanced in specific regions that we discuss here, with the northern Bering and Chukchi Seas sustaining some of the highest water column production and benthic faunal soft-bottom biomass in the world ocean. In addition, these organic carbon-rich Pacific waters are periodically advected into low productivity regions of the nearshore northern Bering, Chukchi and Beaufort Seas off Alaska and sometimes into the East Siberian Sea, all of which have lower productivity on an annual basis. Thus, these near shore areas are intimately tied to nutrients and advected particulate organic carbon from the Pacific influenced Bering Shelf-Anadyr water. Given the short food chains and dependence of many apex predators on sea ice, recent

  12. Coupled organic and inorganic carbon cycling in the deep subseafloor sediment of the northeastern Bering Sea Slope (IODP Exp. 323)

    DEFF Research Database (Denmark)

    Wehrmann, Laura M.; Risgaard-Petersen, Nils; Schrum, Heather;

    2011-01-01

    We studied microbially mediated diagenetic processes driven by carbon mineralization in subseafloor sediment of the northeastern Bering Sea Slope to a depth of 745 meters below seafloor (mbsf). Sites U1343, U1344 and U1345 were drilled during Integrated Ocean Drilling Program (IODP) Expedition 323...... patterns that we observe in the Bering Sea Slope sediment may be representative of passive continental margin settings in high-productivity areas of the world's ocean....

  13. Pacific walrus (Odobenus rosmarus divergens resource selection in the Northern Bering Sea.

    Directory of Open Access Journals (Sweden)

    Chadwick V Jay

    Full Text Available The Pacific walrus is a large benthivore with an annual range extending across the continental shelves of the Bering and Chukchi Seas. We used a discrete choice model to estimate site selection by adult radio-tagged walruses relative to the availability of the caloric biomass of benthic infauna and sea ice concentration in a prominent walrus wintering area in the northern Bering Sea (St. Lawrence Island polynya in 2006, 2008, and 2009. At least 60% of the total caloric biomass of dominant macroinfauna in the study area was composed of members of the bivalve families Nuculidae, Tellinidae, and Nuculanidae. Model estimates indicated walrus site selection was related most strongly to tellinid bivalve caloric biomass distribution and that walruses selected lower ice concentrations from the mostly high ice concentrations that were available to them (quartiles: 76%, 93%, and 99%. Areas with high average predicted walrus site selection generally coincided with areas of high organic carbon input identified in other studies. Projected decreases in sea ice in the St. Lawrence Island polynya and the potential for a concomitant decline of bivalves in the region could result in a northward shift in the wintering grounds of walruses in the northern Bering Sea.

  14. IODP Expedition 323—Pliocene and Pleistocene Paleoceanographic Changes in the Bering Sea

    Directory of Open Access Journals (Sweden)

    Carlos Alvarez Zarikian

    2011-03-01

    Full Text Available High-resolution paleoceanography of the Plio-Pleistocene is important in understanding climate forcing mechanisms and the associated environmental changes. This is particularly true in high-latitude marginal seas such as the Bering Sea, which has been very sensitive to changes in global climate during interglacial and glacial or Milankovitch time scales. This is due to significant changes in water circulation, land-ocean interaction, and sea-ice formation. With theaim to reveal the climate and oceanographic history of the Bering Sea over the past 5 Ma, Integrated Ocean Drilling Program (IODP Expedition 323 cored a total of 5741 meters of sediment (97.4% recovery at seven sites covering three different areas: Umnak Plateau, Bowers Ridge, and the Bering slope region. Four deep holes range from 600 m to 745 m spanning in age from 1.9 Ma to 5 Ma. The water depths (819 m to 3173 m allow characterization of past verticalwater mass distribution such as the oxygen minimum zone (OMZ. The results highlight three key points. (1 The first is an understanding of long-term evolution of surface-water mass distribution during the past 5 Ma including past sea-ice distribution and warm and less eutrophic subarctic Pacific water mass entry into the Bering Sea. (2 We characterized relatively stagnant intermediate water mass distribution imprinted as laminated sediment intervals that have beenubiquitously encountered. Today, the OMZ impinges upon the sediments at ~700–1600 m water depths. In the past, the OMZ appears to have occurred mainly during interglacial periods. Changes in low oxygen-tolerant benthic foraminiferal faunas clearly concur with this observation. (3 We also characterized significant changes between glacial episode of terrigenous sedimentary supply and interglacialepisode of diatom flux.

  15. The Bering Sea Project Archive: a Prototype for Improved Discovery and Access

    Science.gov (United States)

    Stott, D.; Mayernik, M. S.; Daniels, M. D.; Moore, J. A.; Williams, S. F.; Allison, J.

    2015-12-01

    The Bering Sea Project was a research program from 2007 through 2012 that sought to understand the impacts of climate change and dynamic sea ice cover on the eastern Bering Sea ecosystem. More than 100 scientists engaged in field data collection, original research, and ecosystem modeling to link climate, physical oceanography, plankton, fishes, seabirds, marine mammals, humans, traditional knowledge and economic outcomes. Over the six-year period of the program hundreds of multidisciplinary datasets coming from a variety of instrumentation and measurement platforms within thirty-one categories of research were processed and curated by the National Center for Atmospheric Research (NCAR) Earth Observing Laboratory (EOL). For the investigator proposing a field project, the researcher performing synthesis, or the modeler seeking data for verification, the easy discovery and access to the most relevant data is of prime importance. The heterogeneous products of oceanographic field programs such as the Bering Sea Project challenge the ability of researchers to identify which data sets, people, or tools might be relevant to their research, and to understand how certain data, instruments, or methods were used to produce particular results.EOL, as a partner in the NSF funded EarthCollab project, is using linked open data to permit the direct interlinking of information and data across platforms and projects. We are leveraging an existing open-source semantic web application, VIVO, to address connectivity gaps across distributed networks of researchers and resources and identify relevant content, independent of location. We will present our approach in connecting ontologies and integrating them within the VIVO system, using the Bering Sea Project datasets as a case study, and will provide insight into how the geosciences can leverage linked data to produce more coherent methods of information and data discovery across large multi-disciplinary projects.

  16. Distribution of 226Ra in the Arctic Ocean and the Bering Sea and its hydrologic implications

    Institute of Scientific and Technical Information of China (English)

    邢娜; 陈敏; 黄奕普; 蔡平河; 邱雨生

    2003-01-01

    Radium-226 (226Ra) activities were measured in the surface water samples collected from the Arctic Ocean and the Bering Sea during the First Chinese National Arctic Research Expedition. The results showed that 226Ra concentrations in the surface water ranged from 0.28 to 1.56 Bq/m3 with an average of 0.76 Bq/m3 in the Arctic Ocean, and from 0.25 to 1.26 Bq/m3 with an average of 0.71 Bq/m3 in the Bering Sea. The values were obviously lower than those from open oceans in middle and low latitudes, indicating that the study area may be partly influenced by sea ice meltwater. In the Bering Sea, 226Ra in the surface water decreased northward, probably as a result of the exchange between the 226Ra-deficientsea ice meltwater and the 226Ra-rich Pacific water. In the Arctic Ocean, 226Ra in the surface water increased northward and eastward. This spatial distributionof 226Ra reflected the variation of the 226Ra-enriched river component in the water mass of the Arctic Ocean. The vertical profiles of 226Ra in the Canadian Basin showed a concentration maximum at 200 m, which could be attributed to the inputs of the Pacific water or/and the bottom shelf water with high 226Ra concentration. This conclusion was consistent with the results from 2H, 18O tracers.

  17. Atmospheric organochlorine pollutants and air-sea exchange of hexachlorocyclohexane in the Bering and Chukchi seas

    Science.gov (United States)

    Hinckley, Daniel A.; Bidleman, Terry F.; Rice, Clifford P.

    1991-04-01

    Organochlorine pesticides have been found in Arctic fish, marine mammals, birds, and plankton for some time. The lack of local sources and remoteness of the region imply long-range transport and deposition of contaminants into the Arctic from sources to the south. While on the third Soviet-American Joint Ecological Expedition to the Bering and Chukchi Seas (August 1988), high-volume air samples were taken and analyzed for Organochlorine pesticides. Hexachlorocyclohexane (HCH), hexachlorobenzene, polychlorinated camphenes, and chlordane (listed in order of abundance, highest to lowest) were quantified. The air-sea gas exchange of HCH was estimated at 18 stations during the cruise. Average α-HCH concentrations in concurrent atmosphere and surface water samples were 250 pg m-3 and 2.4 ng L-1, respectively, and average γ-HCH concentrations were 68 pg m-3 in the atmosphere and 0.6 ng L-1 in surface water. Calculations based on experimentally derived Henry's law constants showed that the surface water was undersaturated with respect to the atmosphere at most stations (α-HCH, average 79% saturation; γ-HCH, average 28% saturation). The flux for α-HCH ranged from -47 ng m-2 day-1 (sea to air) to 122 ng m-2 d-1 (air to sea) and averaged 25 ng m-2 d-1 air to sea. All fluxes of γ-HCH were from air to sea, ranged from 17 to 54 ng m-2 d-1, and averaged 31 ng m-2 d-1.

  18. Simulation of phytoplankton distribution and variation in the Bering-Chukchi Sea using a 3-D physical-biological model

    Science.gov (United States)

    Hu, Haoguo; Wang, Jia; Liu, Hui; Goes, Joaquim

    2016-06-01

    A three-dimensional physical-biological model has been used to simulate seasonal phytoplankton variations in the Bering and Chukchi Seas with a focus on understanding the physical and biogeochemical mechanisms involved in the formation of the Bering Sea Green Belt (GB) and the Subsurface Chlorophyll Maxima (SCM). Model results suggest that the horizontal distribution of the GB is controlled by a combination of light, temperature, and nutrients. Model results indicated that the SCM, frequently seen below the thermocline, exists because of a rich supply of nutrients and sufficient light. The seasonal onset of phytoplankton blooms is controlled by different factors at different locations in the Bering-Chukchi Sea. In the off-shelf central region of the Bering Sea, phytoplankton blooms are regulated by available light. On the Bering Sea shelf, sea ice through its influence on light and temperature plays a key role in the formation of blooms, whereas in the Chukchi Sea, bloom formation is largely controlled by ambient seawater temperatures. A numerical experiment conducted as part of this study revealed that plankton sinking is important for simulating the vertical distribution of phytoplankton and the seasonal formation of the SCM. An additional numerical experiment revealed that sea ice algae account for 14.3-36.9% of total phytoplankton production during the melting season, and it cannot be ignored when evaluating primary productivity in the Arctic Ocean.

  19. Three-dimensional general circulation model of the northern Bering Sea's summer ecohydrodynamics

    OpenAIRE

    Nihoul, J.C.J.; Adam, P.; P. Brasseur; E. Deleersnijder; Djendi, S.; Haus, J.

    1993-01-01

    The main features of the northern Bering Sea's summer ecohydrodynamics are investigated with the help of two three-dimensional-direct and inverse-models developed at the GeoHydrodynamics and Environment Research Laboratory of the University of Liege (GHER). Each model consists of two interacting sectorial submodels for (i) the general circulation hydrodynamics and synoptic structures, and (ii) the associated plankton ecosystem dynamics.The direct model is used to simulate, from an initial sta...

  20. Historical bottle data collected from the Sea of Okhotsk, Bering Sea, Japan Sea, and North Pacific Ocean by multiple Russian, Former Soviet Union, and Japan platforms in 1888 - 1936 years (NODC Accession 0101422)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Historical bottle data collected from the Sea of Okhotsk,Bering Sea, Japan Sea, and North Pacific Ocean in 1888 - 1936 years by multiple Russian, Former Soviet...

  1. The significance of water column nitrification in the southeastern Bering Sea

    Institute of Scientific and Technical Information of China (English)

    Clara J Deal; JIN Mei-bing; WANG Jia

    2008-01-01

    Nitrate is considered the nutrient that limits new primary production in the southeastern Bering Sea shelf. Nitrate regenerated through biological nitrification has the potential to significantly support primary production as well. Here we use measurements of the specific rate of water column nitrification in a 1-D ecosystem model to quantify the resupply of nitrate from nitrification in the middle shelf of the southeastern Bering Sea. Model sensitivity studies reveal nitrification rate is an important control on the dominant phytoplankton functional type, and the amount of nitrate in summer bottom waters and in the winter water column. Evaluation of nitrification using the model supports the hypothesis that increases in late-summer nitrate concentrations observed in the southeastern Bering Sea bottom waters are due to nitrification. Model results for nitrate replenishment exceed previously estimated rates of 20-30% based on observations. The results of this study indicate that nitrification, potentially the source of up to ~ 38% of the springtime water column nitrate, could support ~ 24% of the annual primary production.

  2. Seasonal distribution of dissolved inorganic carbon and net community production on the Bering Sea shelf

    Directory of Open Access Journals (Sweden)

    J. T. Mathis

    2010-01-01

    Full Text Available The southeastern shelf of the Bering Sea is one of the ocean's most productive ecosystems and sustains more than half of the total US fish landings annually. However, the character of the Bering Sea shelf ecosystem has undergone a dramatic shift over the last several decades, causing notable increases in the dominance of temperate features coupled to the decline of arctic species and decreases in the abundance of commercially important organisms. In order to assess the current state of primary production in the southeastern Bering Sea, we measured the spatio-temporal distribution and controls on dissolved inorganic carbon (DIC concentrations in spring and summer of 2008 across six shelf domains defined by differing biogeochemical characteristics. DIC concentrations were tightly coupled to salinity in spring and ranged from ~1900 μmol kg−1 over the inner shelf to ~2400 μmol kg−1 in the deeper waters of the Bering Sea. In summer, DIC concentrations were lower due to dilution from sea ice melt and primary production. Concentrations were found to be as low ~1800 μmol kg−1 over the inner shelf. We found that DIC concentrations were drawn down 30–150 μmol kg−1 in the upper 30 m of the water column due to primary production between the spring and summer occupations. Using the seasonal drawdown of DIC, estimated rates of net community production (NCP on the inner, middle, and outer shelf averaged 28±10 mmol C m−2 d−1. However, higher rates of NCP (40–47 mmol C m−2 d−1 were observed in the ''Green Belt'' where the greatest confluence of nutrient-rich basin water and iron-rich shelf water occurs. We estimated that in 2008, total productivity across the shelf was on the order of ~105 Tg C yr−1. Due to the paucity of consistent, comparable productivity data, it is impossible at this time to quantify whether the system is becoming

  3. Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments from the Bering Sea and western Arctic Ocean.

    Science.gov (United States)

    Zhao, Mengwei; Wang, Weiguo; Liu, Yanguang; Dong, Linsen; Jiao, Liping; Hu, Limin; Fan, Dejiang

    2016-03-15

    To analyze the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) and evaluate their potential ecological risks, the concentrations of 16 PAHs were measured in 43 surface sediment samples from the Bering Sea and western Arctic Ocean. Total PAH (tPAH) concentrations ranged from 36.95 to 150.21 ng/g (dry weight). In descending order, the surface sediment tPAH concentrations were as follows: Canada Basin>northern Chukchi Sea>Chukchi Basin>southern Chukchi Sea>Aleutian Basin>Makarov Basin>Bering Sea shelf. The Bering Sea and western Arctic Ocean mainly received PAHs of pyrogenic origin due to pollution caused by the incomplete combustion of fossil fuels. The concentrations of PAHs in the sediments of the study areas did not exceed effects range low (ERL) values. PMID:26806662

  4. Distribution of dissolved oxygen and causes of maximum concentration in the Bering Sea in July 2010

    Institute of Scientific and Technical Information of China (English)

    SUN Xiuwu; LIN Cai; CHEN Yong; ZHANG Yuanbiao; WANG Jigang; JI Weidong

    2014-01-01

    According to data obtained in the Bering Sea during the 4th Chinese National Arctic Research Expedition, the distribution of dissolved oxygen (DO) was studied, causes of its maximum concentration were discussed, and the relationships between DO and other parameters, such as salinity, temperature, and chlorophyll a were analyzed. The results showed DO concentration ranged from 0.53 to 12.05 mg/L in the Bering Sea ba-sin. The upper waters contained high concentrations and the maximum occurred at the depth range from 20 to 50 m. The DO concentration decreased rapidly when the depth was deeper than 200 m and reached the minimum at the depth range from 500 to 1 000 m, and then increased slowly with the depth increasing but still kept at a low level. On the shelf, the DO concentration ranged from 6.53 to 16.63 mg/L with a mean value of 10.75 mg/L, and showed a characteristic of decreasing from north to south. The DO concentration was higher in the area between the Bering Sea and Lawrence Island and was lower in the southeast and southwest of Lawrence Island at the latitude of 62°N. The formation of maximum DO concentration was concerned with phytoplankton photosynthesis and formation of the themocline. To the south of Sta. B07 in the Bering Sea basin, the oxygen produced by photosynthesis permeated to the deeper water and the themocline made it difficult to exchange vertically, and to the north of Sta. B07, the maximum DO concen-tration occurred above the themocline due to phytoplankton activities. On the shelf, the oxygen produced by phytoplankton photosynthesis gathered at the bottom of the thermocline and formed the DO maximum concentration. In the Bering Sea basin, the DO and salinity showed a weak negative correlation (r=0.40) when the salinity was lower than 33.1, a significant negative correlation (r=0.92) when the salinity ranged from 33.1 to 33.7, and an irregular reversed parabola (r=0.95) when the salinity was greater than 33.7.

  5. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering and Chukchi seas

    Science.gov (United States)

    Sasaki, Hiroko; Matsuno, Kohei; Fujiwara, Amane; Onuka, Misaki; Yamaguchi, Atsushi; Ueno, Hiromichi; Watanuki, Yutaka; Kikuchi, Takashi

    2016-08-01

    The advection of warm Pacific water and the reduction in sea ice in the western Arctic Ocean may influence the abundance and distribution of copepods, a key component of food webs. To quantify the factors affecting the abundance of copepods in the northern Bering and Chukchi seas, we constructed habitat models explaining the spatial patterns of large and small Arctic and Pacific copepods separately. Copepods were sampled using NORPAC (North Pacific Standard) nets. The structures of water masses indexed by principle component analysis scores, satellite-derived timing of sea ice retreat, bottom depth and chlorophyll a concentration were integrated into generalized additive models as explanatory variables. The adequate models for all copepods exhibited clear continuous relationships between the abundance of copepods and the indexed water masses. Large Arctic copepods were abundant at stations where the bottom layer was saline; however they were scarce at stations where warm fresh water formed the upper layer. Small Arctic copepods were abundant at stations where the upper layer was warm and saline and the bottom layer was cold and highly saline. In contrast, Pacific copepods were abundant at stations where the Pacific-origin water mass was predominant (i.e. a warm, saline upper layer and saline and a highly saline bottom layer). All copepod groups showed a positive relationship with early sea ice retreat. Early sea ice retreat has been reported to initiate spring blooms in open water, allowing copepods to utilize more food while maintaining their high activity in warm water without sea ice and cold water. This finding indicates that early sea ice retreat has positive effects on the abundance of all copepod groups in the northern Bering and Chukchi seas, suggesting a change from a pelagic-benthic-type ecosystem to a pelagic-pelagic type.

  6. Abundance of general aerobic heterotrophic bacteria in the Bering Sea and Chukchi Sea and their adaptation to temperature

    Institute of Scientific and Technical Information of China (English)

    陈皓文; 高爱国; 孙海青; 矫玉田

    2004-01-01

    The abundance of general aerobic heterotrophic bacteria(GAB) from the water and sediment in the Bering Sea and the Chukchi Sea was determined by using petri dish cultivation and counting method. The abundance of GAB among the different sea areas, sampling sites, layers of sediments surveyed and adaptability to differential temperatures was studied. The result obtained showed that: the occurrence percentage of GAB in the surface water was higher than that in sediment, but the abundance was only 0.17% of sediment. The occurrence percentage of GAB in surficial layer of sediment was higher than that in the other layers. The occurrence percentage of GAB in surficial layer of sediment was higher than that in the other layers. The occurrence percentage, abundance and its variation of GAB in the Bering Sea were higher than that in the Chukchi Sea respectively. The average value of the abundance of GAB in sediment showed a trend: roughly higher in the lower latitudinal area than higher latitude. The results from temperature test mean that: the majority of bacteria tested were cold -adapted ones, minority might be mesophilic bacteria. The results indicated that, Arctic ocean bacteria had a stronger adaptability to environmental temperature.

  7. Bering Sea surface water conditions during Marine Isotope Stages 12 to 10 at Navarin Canyon (IODP Site U1345)

    Science.gov (United States)

    Caissie, Beth E.; Brigham-Grette, Julie; Cook, Mea S.; Colmenero-Hidalgo, Elena

    2016-09-01

    Records of past warm periods are essential for understanding interglacial climate system dynamics. Marine Isotope Stage 11 occurred from 425 to 394 ka, when global ice volume was the lowest, sea level was the highest, and terrestrial temperatures were the warmest of the last 500 kyr. Because of its extreme character, this interval has been considered an analog for the next century of climate change. The Bering Sea is ideally situated to record how opening or closing of the Pacific-Arctic Ocean gateway (Bering Strait) impacted primary productivity, sea ice, and sediment transport in the past; however, little is known about this region prior to 125 ka. IODP Expedition 323 to the Bering Sea offered the unparalleled opportunity to look in detail at time periods older than had been previously retrieved using gravity and piston cores. Here we present a multi-proxy record for Marine Isotope Stages 12 to 10 from Site U1345, located near the continental shelf-slope break. MIS 11 is bracketed by highly productive laminated intervals that may have been triggered by flooding of the Beringian shelf. Although sea ice is reduced during the early MIS 11 laminations, it remains present at the site throughout both glacials and MIS 11. High summer insolation is associated with higher productivity but colder sea surface temperatures, which implies that productivity was likely driven by increased upwelling. Multiple examples of Pacific-Atlantic teleconnections are presented including laminations deposited at the end of MIS 11 in synchrony with millennial-scale expansions in sea ice in the Bering Sea and stadial events seen in the North Atlantic. When global eustatic sea level was at its peak, a series of anomalous conditions are seen at U1345. We examine whether this is evidence for a reversal of Bering Strait throughflow, an advance of Beringian tidewater glaciers, or a turbidite.

  8. The relationship between cyanobacteria and environmental factors in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    肖天; 孙松; 张武昌; 李超伦; 金明明

    2002-01-01

    During the first Chinese Scientific Expedition to the Arctic in July - September 1999, cyanobacteria in the Bering Sea were measured by epifluorescence microscopy. Cyanobacterial abundance varied from 0 to 7.93×103 cell/ml and decreased along a northerly directed latitudinal gradient in horizontal distribution. Cyanobacteria did not occur at station B1-12 (north of 60 °N). Vertically, high cyanobacterial abundance appeared in the upper 25 - 50 m and decreased rapidly below 50 m. There were no cyanobacteria at the 150 m. Seawater temperature and NH+4-N are suggested to affect the distribution of cyanobacteria.

  9. Latitudinal trends and temporal shifts in the catch composition of bottom trawls conducted on the eastern Bering Sea shelf

    Science.gov (United States)

    Stevenson, Duane E.; Lauth, Robert R.

    2012-06-01

    Latitudinal species diversity gradients are well known in both terrestrial and aquatic ecosystems throughout the world. However, trends in relative abundance and other shifts in community structure with latitude, which can be more sensitive to environmental shifts such as climate change, have received less attention. Here we investigate latitudinal trends in the seafloor community of the eastern Bering Sea using catches of fishes and epibenthic invertebrates in bottom trawl surveys conducted from 1982 to 2010. Our results indicate that the overall biomass of the epibenthic community declines with increasing latitude in the eastern Bering Sea. This latitudinal trend is primarily driven by declining fish catches in the northern Bering Sea, which in turn reflects changes in the structure of the fish community. The fish fauna in northern latitudes is increasingly dominated by gadids, though the species composition of the gadid fauna also changes with latitude, with smaller species becoming more common in the north. The biomass of the invertebrate megafauna remains relatively consistent throughout the eastern Bering Sea, but invertebrates make up a larger proportion of the catch in bottom trawls conducted at higher latitudes. The epibenthic invertebrate megafauna in the eastern Bering Sea is composed primarily of sea stars (Asteriidae) and oregoniid crabs (Chionoecetes and Hyas), though no clear latitudinal trends in the invertebrate community are evident. Limited trawl data from the eastern Chukchi Sea indicate that the fish community farther north is even more heavily dominated by gadids, and the epibenthic invertebrate community is dominated by asteriid sea stars. Temperature data from bottom trawl surveys in the southeastern Bering Sea over the past decade indicate that there was a distinct temperature shift around 2005, and the relatively warm years of 2001-2005 were followed by five relatively cold years. This shift in the summer temperature regime of the Bering

  10. The substance composition of sterols in the sediments from the Chukchi Sea, the Bering Sea and global climatic significance

    Institute of Scientific and Technical Information of China (English)

    Lu Bing; Hu Chuanyu; Pan Jianming; Xue Bin; YaoMei

    2006-01-01

    The compounds of sterols such as C27 、C28 、C29 and C3o are recorded from C-8 core of the Chukchi Sea. The double bond position is located at 5-, 5 ,22 as well as 22-,24-. The compound of sterols such as C27、C28、C29 are recorded from B2-9core of the Bering Sea. The double bond position is located at 5-, 5, 22 as well as 22. The composition characteristics of sterols indicate that the substance is mainly contributed by the terrigenous origin and marine silicate organisms. The results are also suggest that the record of abnormal sterols from the surface sediments (2 -0 cm)in the Chukchi Sea and the Bering Sea represent the period from 1980s to the late 1990s. The strong signal of the Arctic warming is preserved in the sediments, which indicates the eco- environmental change responding to climatic effect of circumjacent.

  11. Submarine canyons as coral and sponge habitat on the eastern Bering Sea slope

    Directory of Open Access Journals (Sweden)

    Robert J. Miller

    2015-07-01

    Full Text Available Submarine canyons have been shown to positively influence pelagic and benthic biodiversity and ecosystem function. In the eastern Bering Sea, several immense canyons lie under the highly productive “green belt” along the continental slope. Two of these, Pribilof and Zhemchug canyons, are the focus of current conservation interest. We used a maximum entropy modeling approach to evaluate the importance of these two canyons, as well as canyons in general, as habitat for gorgonian (alcyonacean corals, pennatulacean corals, and sponges, in an area comprising most of the eastern Bering Sea slope and outer shelf. These invertebrates create physical structure that is a preferred habitat for many mobile species, including commercially important fish and invertebrates. We show that Pribilof canyon is a hotspot of structure-forming invertebrate habitat, containing over 50% of estimated high-quality gorgonian habitat and 45% of sponge habitat, despite making up only 1.7% of the total study area. The amount of quality habitat for gorgonians and sponges varied in other canyons, but canyons overall contained more high-quality habitat for structure-forming invertebrates compared to other slope areas. Bottom trawling effort was not well correlated with habitat quality for structure-forming invertebrates, and bottom-contact fishing effort in general, including longlining and trawling, was not particularly concentrated in the canyons examined. These results suggest that if conserving gorgonian coral habitat is a management goal, canyons, particularly Pribilof Canyon, may be a prime location to do this without excessive impact on fisheries.

  12. Community structure and spatial distribution of macrobenthos in the shelf area of the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Jianjun; HE Xuebao; LIN Heshan; LIN Junhui; HUANG Yaqin; ZHENG Chengxing; ZHENG Fengwu; LI Rongguan; JIANG Jinxiang

    2014-01-01

    Field investigations of marine macrobenthos were conducted at ten sites in the Bering Sea in July 2010. Alto-gether 90 species of macrobenthos belonging to 59 families and 78 genera were identified. Among them, 41 polychaetes, 16 mollusks, 23 crustaceans, three echinoderms, two cnidarians, one nemertean, one priapu-lid, two sipunculids, and one echiuran were identified. The average density and biomass of total macrob-enthos were 984 ind./m2 and 1 207.1 g/m2 of wet weight, respectively. The predominant species in the study area were Scoloplos armiger, Eudorella pacifica, Ophiura sarsii, Heteromastus filiformis, Ennucula tenuis, and Harpiniopsis vadiculus by abundance, while the predominant species in this area was Echinarachnius parma by biomass. Hierarchical cluster analysis (Bray-Curtis similarity measure) revealed that two impor-tant benthic assemblages in the study area were Community A and Community B. Community A was stable and Community B was unstable, as shown by the Abundance/Biomass Comparisons (ABC) approach. The macrobenthic community structure in the shelf of the Bering Sea was characterized by its high abundance and biomass, high productivity but great heterogeneity.

  13. 76 FR 55276 - Fisheries of the Exclusive Economic Zone Off Alaska; Octopus in the Bering Sea and Aleutian Islands

    Science.gov (United States)

    2011-09-07

    ... of the BSAI (76 FR 11139, March 1, 2011) and an apportionment from the non-specified reserve of groundfish (76 FR 17360, March 29, 2011). In accordance with Sec. 679.20(d)(2), the Administrator, Alaska... Economic Zone Off Alaska; Octopus in the Bering Sea and Aleutian Islands AGENCY: National Marine...

  14. 77 FR 59852 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2012-10-01

    ... at final action and that the policy change would destabilize status quo management of groundfish... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management Area; Amendment 97 ACTION: Final rule. SUMMARY: NMFS publishes regulations to implement Amendment 97 to the Fishery Management Plan...

  15. 75 FR 48298 - Groundfish Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab...

    Science.gov (United States)

    2010-08-10

    ... Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab Rationalization Program; Recordkeeping... removes the Crab Rationalization Program requirements for catcher/processors to weigh all offloaded crab... INFORMATION CONTACT: Patsy A. Bearden, 907-586-7228. SUPPLEMENTARY INFORMATION: NMFS manages the U.S....

  16. 75 FR 56485 - Groundfish Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab...

    Science.gov (United States)

    2010-09-16

    ... Register on August 10, 2010 (75 FR 48298), with a public comment period that closed August 25, 2010. One... Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab Rationalization Program; Recordkeeping... Administration (NOAA), Commerce. ACTION: Final rule. SUMMARY: NMFS issues regulations to remove the...

  17. 76 FR 47155 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-08-04

    ... Alaska; Bering Sea and Aleutian Islands Crab Rationalization Program; Public Meeting AGENCY: National... crab fisheries managed under the BSAI Crab Rationalization program. The CIE, operated by Northern Taiga... products. The BSAI Crab Economic Data Report (EDR) program administered by NMFS began collecting...

  18. 76 FR 17088 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-03-28

    ... published on March 2, 2005 (70 FR 10174), and are located at 50 CFR part 680. Regulations implementing the... 2011 and 2012 harvest specifications (75 FR 76352, December 8, 2010), NMFS will publish the final... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab Rationalization Program AGENCY:...

  19. 75 FR 7205 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2010-02-18

    ... final rule implementing the Crab Rationalization Program (Program) was published on March 2, 2005 (70 FR... fishery would be caused in the time it would take to follow standard rulemaking procedures (62 FR 44421... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab Rationalization Program; Emergency...

  20. 76 FR 49423 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-08-10

    ... the arbitration system is found in the preambles to the proposed rule (September 1, 2004; 69 FR 53397) and final rule (March 2, 2005; 70 FR 10174) that implemented the CR Program, as well as in the final... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab Rationalization Program AGENCY:...

  1. 78 FR 35572 - Fisheries of the Exclusive Economic Zone Off Alaska; Northern Rockfish in the Bering Sea and...

    Science.gov (United States)

    2013-06-13

    ... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XC722 Fisheries of the Exclusive Economic Zone Off Alaska; Northern Rockfish in the Bering Sea and Aleutian Islands Management Area AGENCY... the BSAI (78 FR 13813, March 1, 2013), NMFS closed the directed fishery for northern rockfish...

  2. 77 FR 48916 - Fisheries of the Exclusive Economic Zone Off Alaska; Arrowtooth Flounder in the Bering Sea and...

    Science.gov (United States)

    2012-08-15

    ... INFORMATION: NMFS manages the groundfish fishery in the (BSAI) exclusive economic zone according to the... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XC129 Fisheries of the Exclusive Economic Zone Off Alaska; Arrowtooth Flounder in the Bering Sea and Aleutian Islands Management Area...

  3. 78 FR 42023 - Fisheries of the Exclusive Economic Zone Off Alaska; Atka Mackerel in the Bering Sea and Aleutian...

    Science.gov (United States)

    2013-07-15

    ... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XC752 Fisheries of the Exclusive Economic Zone Off Alaska; Atka Mackerel in the Bering Sea and Aleutian Islands Management Area AGENCY... under Sec. 679.2(d)(1)(iii) on June 11, 2013 (78 FR 35771, June 14, 2013). As of July 8, 2013, NMFS...

  4. 76 FR 39792 - Fisheries of the Exclusive Economic Zone Off Alaska; Northern Rockfish in the Bering Sea and...

    Science.gov (United States)

    2011-07-07

    ... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XA547 Fisheries of the Exclusive Economic Zone Off Alaska; Northern Rockfish in the Bering Sea and Aleutian Islands Management Area AGENCY... the final 2011 and 2012 harvest specifications for groundfish in the BSAI (76 FR 11139, March 1,...

  5. 78 FR 74063 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands; 2014 and...

    Science.gov (United States)

    2013-12-10

    ... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XC927 Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands; 2014 and 2015 Harvest Specifications for... specifications published in the Federal Register on March 1, 2013 (78 FR 13813) except for Pacific cod...

  6. 78 FR 57537 - Fisheries of the Exclusive Economic Zone Off Alaska; Shortraker Rockfish in the Bering Sea and...

    Science.gov (United States)

    2013-09-19

    ... fishery in the BSAI exclusive economic zone according to the Fishery Management Plan for Groundfish of the... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XC876 Fisheries of the Exclusive Economic Zone Off Alaska; Shortraker Rockfish in the Bering Sea and Aleutian Islands Management Area...

  7. 77 FR 12214 - Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pollock in the Bering Sea...

    Science.gov (United States)

    2012-02-29

    ... the groundfish fishery in the BSAI exclusive economic zone according to the Fishery Management Plan... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XB038 Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pollock in the Bering Sea and Aleutian Islands AGENCY:...

  8. 78 FR 14932 - Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pollock in the Bering Sea...

    Science.gov (United States)

    2013-03-08

    ...: NMFS manages the groundfish fishery in the BSAI exclusive economic zone according to the Fishery... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XC543 Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pollock in the Bering Sea and Aleutian Islands AGENCY:...

  9. 75 FR 14498 - Fisheries of the Exclusive Economic Zone Off Alaska; Atka Mackerel in the Bering Sea and Aleutian...

    Science.gov (United States)

    2010-03-26

    .... SUPPLEMENTARY INFORMATION: NMFS manages the groundfish fishery in the BSAI exclusive economic zone according to... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XV52 Fisheries of the Exclusive Economic Zone Off Alaska; Atka Mackerel in the Bering Sea and Aleutian Islands Management Area...

  10. Recent Bering Sea warm and cold events in a 95-year context

    Science.gov (United States)

    Overland, James E.; Wang, Muyin; Wood, Kevin R.; Percival, Donald B.; Bond, Nicholas A.

    2012-06-01

    The meteorology and oceanography of the southeastern Bering Sea shelf was recently dominated by a multi-year warm event (2000-2005) followed by a multi-year cold event (2007-2010). We put these recent events into the context of the 95-year air temperature record from St. Paul Island and with concurrent spatial meteorological fields. For March 2000-2005 the mean air temperature anomaly at St. Paul was 2.1 °C above the long-term mean, and for March 2007-2010 the mean temperature anomaly at St. Paul was 4.7 °C below the long-term mean. The only multi-year temperature deviations comparable to the first decade of the 2000s are a cold event from 1971 to 1976 followed by a warm event from 1978 to 1983. There was also a short warm event 1935-1937. The temperature transition between warm and cold events in the 1970s and 2000s took two years. While there are theoretical arguments for some physical memory processes in the North Pacific climate system, we cannot rule out that the recent warm and cold events are of a random nature: they are rare in the St. Paul temperature record, they are dominated by North Pacific-wide sea level pressure events rather than local Bering Sea processes, and they are consistent with a red noise model of climate variability. The 1970s transition appears to have an ENSO (El Niño-Southern Oscillation) influence, while the recent events are likely connected to Arctic-wide warming. Evidence provided by the 95-year St. Paul meteorological record reinforces the idea that a red-noise model of climate variability is appropriate for the North Pacific and southeastern Bering Sea. We stress the importance of relatively rare sub-decadal events and shifts, rather than multi-decadal variability associated with the Pacific Decadal Oscillation (PDO). Thus, in the future we can expect large positive and negative excursions in the region that can last for multiple years, but there is as yet little predictability for their timing and duration.

  11. Seasonal distribution of dissolved inorganic carbon and net community production on the Bering Sea shelf

    Directory of Open Access Journals (Sweden)

    J. T. Mathis

    2010-05-01

    Full Text Available In order to assess the current state of net community production (NCP in the southeastern Bering Sea, we measured the spatio-temporal distribution and controls on dissolved inorganic carbon (DIC concentrations in spring and summer of 2008 across six shelf domains defined by differing biogeochemical characteristics. DIC concentrations were tightly coupled to salinity in spring and ranged from ~1900 μmoles kg−1 over the inner shelf to ~2400 μmoles kg−1 in the deeper waters of the Bering Sea. In summer, DIC concentrations were lower due to dilution from sea ice melt, terrestrial inputs, and primary production. Concentrations were found to be as low ~1800 μmoles kg−1 over the inner shelf. We found that DIC concentrations were drawn down 30–150 μmoles kg−1 in the upper 30 m of the water column due to primary production and calcium carbonate formation between the spring and summer occupations. Using the seasonal drawdown of DIC, estimated rates of NCP on the inner, middle, and outer shelf averaged 28 ± 9 mmoles C m−2 d−1. However, higher rates of NCP (40–47 mmoles C m−2 d−1 were observed in the "Green Belt" where the greatest confluence of nutrient-rich basin water and iron-rich shelf water occurs. We estimated that in 2008, total NCP across the shelf was on the order of ~96 Tg C yr−1. Due to the paucity of consistent, comparable productivity data, it is impossible at this time to quantify whether the system is becoming more or less productive. However, as changing climate continues to modify the character of the Bering Sea, we have shown that NCP can be an important indicator of how the ecosystem is functioning.

  12. Community structure and spatial-temporal variation of netz-phytoplankton in the Bering Sea in summer

    Institute of Scientific and Technical Information of China (English)

    WANG Yu; XIANG Peng; YE Youyin; LIN Gengming; YANG Qingliang; LIN Heshan; LIN Mao

    2016-01-01

    Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samplesin situ collected in the Bering Sea in July of 1999 and 2010 were analyzed to obtain phytoplankton community structure and spatial-temporal variation between the beginning and end of this decade, and the correlation of phytoplankton community dynamics and environmental factors was investigated. A total of 5 divisions, 58 genera and 153 species of phytoplankton belonging to 3 ecological groups were identified. The vast majority of phytoplankton consisted of diatoms accounting for 66.7% of the total species and 95.2% of the total abundance. Considering differentiation in spatial extent and phytoplankton sample types, there were subtle changes in species composition, large altering in abundance and significant variation in spatial distribution between two surveys. The abundance peak area was located at the Bering Strait while sub peak was found at the Bering Sea Basin. The boreal-temperate diatom was the dominant flora, which was subsequently replaced by eurythermal and frigid-water diatom. Phytoplankton community in the Bering Sea was not a simplex uniform community but composed of deep-ocean assemblage and neritic assemblage. The deep-ocean assemblage was located in the northwestern Pacific Ocean and Bering Sea Basin, dominated by boreal-temperate species (Neodenticula seminae,Thalassiothrix longissima,Amphiprora hyperborean,Chaetoceros atlanticus,Thalassiosira trifulta, etc.) and eurychoric species (Thalassionema nitzschioides,Ch. compressus,Rhizosolenia styliformis, etc.), and characterized by low abundance, even inter-species abundance allocations, diverse dominant species and high species diversity. The neritic assemblage was distributed on the continental shelf and slope of Bering Sea and was mainly composed of frigid-water species (Th. nordenskiöldii,Ch. furcellatus,Ch. socialis

  13. Sea-ice habitat preference of the Pacific walrus (Odobenus rosmarus divergens) in the Bering Sea: A multiscaled approach

    Science.gov (United States)

    Sacco, Alexander Edward

    The goal of this thesis is to define specific parameters of mesoscale sea-ice seascapes for which walruses show preference during important periods of their natural history. This research thesis incorporates sea-ice geophysics, marine-mammal ecology, remote sensing, computer vision techniques, and traditional ecological knowledge of indigenous subsistence hunters in order to quantitatively study walrus preference of sea ice during the spring migration in the Bering Sea. Using an approach that applies seascape ecology, or landscape ecology to the marine environment, our goal is to define specific parameters of ice patch descriptors, or mesoscale seascapes in order to evaluate and describe potential walrus preference for such ice and the ecological services it provides during an important period of their life-cycle. The importance of specific sea-ice properties to walrus occupation motivates an investigation into how walruses use sea ice at multiple spatial scales when previous research suggests that walruses do not show preference for particular floes. Analysis of aerial imagery, using image processing techniques and digital geomorphometric measurements (floe size, shape, and arrangement), demonstrated that while a particular floe may not be preferred, at larger scales a collection of floes, specifically an ice patch (water concentration. Ice patches that are occupied by adult and juvenile walruses show a small number of characteristics that vary from those ice patches that were visually unoccupied. Using synthetic aperture radar imagery, we analyzed co-located walrus observations and statistical texture analysis of radar imagery to quantify seascape preferences of walruses during the spring migration. At a coarse resolution of 100 -- 9,000 km2, seascape analysis shows that, for the years 2006 -- 2008, walruses were preferentially occupying fragmented pack ice seascapes range 50 -- 89% of the time, when, all throughout the Bering Sea, only range 41 -- 46% of

  14. Discovery of two new large submarine canyons in the Bering Sea

    Science.gov (United States)

    Carlson, P.R.; Karl, Herman A.

    1984-01-01

    The Beringian continental margin is incised by some of the world's largest submarine canyons. Two newly discovered canyons, St. Matthew and Middle, are hereby added to the roster of Bering Sea canyons. Although these canyons are smaller and not cut back into the Bering shelf like the five very large canyons, they are nonetheless comparable in size to most of the canyons that have been cut into the U.S. eastern continental margin and much larger than the well-known southern California canyons. Both igneous and sedimentary rocks of Eocene to Pliocene age have been dredged from the walls of St. Matthew and Middle Canyons as well as from the walls of several of the other Beringian margin canyons, thus suggesting a late Tertiary to Quaternary genesis of the canyons. We speculate that the ancestral Yukon and possibly Anadyr Rivers were instrumental in initiating the canyon-cutting processes, but that, due to restrictions imposed by island and subsea bedrock barriers, cutting of the two newly discovered canyons may have begun later and been slower than for the other five canyons. ?? 1984.

  15. BESMEX: Bering Sea marine mammal experiment. [with the primary target species being the walrus and bowhead whale

    Science.gov (United States)

    Ray, G. C.; Wartzok, D.

    1974-01-01

    Predictive ecological models are being studied for the management and conservation of the walrus, and the bowhead whale in the Bering Sea. The influence of sea ice on the distribution, and carrying capacity of the area for these two mammals is to be investigated with the primary target species being the walrus. Remote sensing and radio tracking is considered a requirement for assessing the walrus ecosystem.

  16. Application of long-chain aikenones and U37k values for paleotemperature estimation in the Arctic Chukchi Sea- Bering Sea area

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    -Long-chain alkenones were detected in samples of sea surface sediments from the Chukchi Sea and the Bering Sea areas, the Arctic Pole. The analysis result indicates that C37:3 methylketone is pre dominate in the long-chain alkenones from the Chukchi and Bering Sea sediments. The abundance of C37to C39 unsaturated alkenones changes in an order of C37 >C38 >C39. Based on ∑37/∑38 ratio, the de tected organism precursors of the long-chain alkenones are mainly coccolithophrid (Emiliania huxleyi).By the calibration relationship between U3k7 and U37k indices, the sea surface paleotemperature in these seas is estimated. The estimated values of U37k vary from 4.147℃ to 5. 706℃, with a mean value of 5.092℃.

  17. Carbon sources and trophic relationships of ice seals during recent environmental shifts in the Bering Sea.

    Science.gov (United States)

    Wang, Shiway W; Springer, Alan M; Budge, Suzanne M; Horstmann, Lara; Quakenbush, Lori T; Wooller, Matthew J

    2016-04-01

    Dramatic multiyear fluctuations in water temperature and seasonal sea ice extent and duration across the Bering-Chukchi continental shelf have occurred in this century, raising a pressing ecological question: Do such environmental changes alter marine production processes linking primary producers to upper trophic-level predators? We examined this question by comparing the blubber fatty acid (FA) composition and stable carbon isotope ratios of individual FA (δ¹³CFA) of adult ringed seals (Pusa hispida), bearded seals (Erignathus barbatus), spotted seals (Phoca largha), and ribbon seals (Histriophoca fasciata), collectively known as "ice seals," sampled during an anomalously warm, low sea ice period in 2002-2005 in the Bering Sea and a subsequent cold, high sea ice period in 2007-2010. δ¹³C(FA) values, used to estimate the contribution to seals of carbon derived from sea ice algae (sympagic production) relative to that derived from water column phytoplankton (pelagic production), indicated that during the cold period, sympagic production accounted for 62-80% of the FA in the blubber of bearded seals, 51-62% in spotted seals, and 21-60% in ringed seals. Moreover, the δ¹³CFA values of bearded seals indicated a greater incorporation of sympagic FAs during the cold period than the warm period. This result provides the first empirical evidence of an ecosystem-scale effect of a putative change in sympagic production in the Western Arctic. The FA composition of ice seals showed clear evidence of resource partitioning among ringed, bearded, and spotted seals, and little niche separation between spotted and ribbon seals, which is consistent with previous studies. Despite interannual variability, the FA composition of ringed and bearded seals showed little evidence of differences in diet between the warm and cold periods. The findings that sympagic production contributes significantly to food webs supporting ice seals, and that the contribution apparently is less in

  18. Physical and underway data collected aboard the HEALY during cruise HLY11TD in the Beaufort Sea, Bering Sea and others from 2011-08-05 to 2011-08-15 (NODC Accession 0103996)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0103996 includes physical and underway data collected aboard the HEALY during cruise HLY11TD in the Beaufort Sea, Bering Sea and others from...

  19. Plankton and other data collected using zooplankton net in the Bering Sea from NOAA Ship MILLER FREEMAN from 16 April 1977 to 15 May 1977 (NODC Accession 7800407)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Plankton and other data were collected using zooplankton net from the NOAA Ship MILLER FREEMAN in the Bering Sea from the 16 April 1977 to 15 May 1977. Data were...

  20. Zooplankton data from net casts in the Bering Sea from NOAA Ship DISCOVERER from 03 August 1976 to 17 August 1976 (NODC Accession 7700433)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected using net casts in the Bering Sea from NOAA Ship DISCOVERER from 03 August 1976 to 17 August 1976. Data were collected by University...

  1. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detailed crab data collected from the annual NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the eastern Bering Sea continental...

  2. AFSC/NMML: Killer whale surveys in the Aleutian Islands, Bering Sea, and western and central Gulf of Alaska, 2001 - 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a compilation of line-transect data collected on surveys in the Aleutian Islands, Bering Sea, and western and central Gulf of Alaska, 2001 - 2010....

  3. AFSC/RACE/FBEP/Hurst: Distributional patterns of 0-group Pacific cod (Gadus macrocephalus) in the eastern Bering Sea under variable recruitment and thermal conditions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is from a study that analyzed the late summer distribution of juvenile Pacific cod in the eastern Bering Sea for 6 cohorts (2004-2009), based on...

  4. Bering Sea Inner Front zooplankton data sets collected with CalVet net on four cruises from 6/3/1997 - 9/1/1998 (NODC Accession 0000103)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton and other data were collected using CalVet net in Bering sea from ALPHA HELIX. Data were collected from 01 June 1997 to 01 September 1998 by University...

  5. Salinity data from moored current meter casts in the Northeast Pacific Ocean, Bering Sea, and Gulf of Alaska from 03 October 1984 - 01 May 1988 (NODC Accession 8900056)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salinity data were collected using moored current meter casts in the North Pacific Ocean, Bering Sea, and Gulf of Alaska from October 3, 1984 to May 1, 1988. Data...

  6. Population dynamics and trophic relationships of marine birds in the Gulf of Alaska and southern Bering Sea: Part I, general introduction: Annual report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Site-specific studies of marine birds were conducted at 13 locations in the Gulf of Alaska and southern Bering Sea during the 1976 field season. Although the...

  7. AFSC/RACE/SAP/Pathobiology: Bitter crab disease prevalence in immature Chionoecetes spp. at 6 index sites in eastern Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains crab data from a field survey of Chionoecetes bairdi and C. opilio collected at six designated index sites in the Bering Sea during the 2014...

  8. Glacial-to-Holocene evolution of sea surface temperature and surface circulation in the subarctic northwest Pacific and the Western Bering Sea

    Science.gov (United States)

    Meyer, Vera D.; Max, Lars; Hefter, Jens; Tiedemann, Ralf; Mollenhauer, Gesine

    2016-07-01

    It has been proposed that North Pacific sea surface temperature (SST) evolution was intimately linked to North Atlantic climate oscillations during the last glacial-interglacial transition. However, during the early deglaciation and the Last Glacial Maximum, the SST development in the subarctic northwest Pacific and the Bering Sea is poorly constrained as most existing deglacial SST records are based on alkenone paleothermometry, which is limited prior to 15 ka B.P. in the subarctic North Pacific realm. By applying the TEXL86 temperature proxy we obtain glacial-Holocene-SST records for the marginal northwest Pacific and the Western Bering Sea. Our TEXL86-based records and existing alkenone data suggest that during the past 15.5 ka, SSTs in the northwest Pacific and the Western Bering Sea closely followed millennial-scale climate fluctuations known from Greenland ice cores, indicating rapid atmospheric teleconnections with abrupt climate changes in the North Atlantic. Our SST reconstructions indicate that in the Western Bering Sea SSTs drop significantly during Heinrich Stadial 1 (HS1), similar to the known North Atlantic climate history. In contrast, progressively rising SST in the northwest Pacific is different to the North Atlantic climate development during HS1. Similarities between the northwest Pacific SST and climate records from the Gulf of Alaska point to a stronger influence of Alaskan Stream waters connecting the eastern and western basin of the North Pacific during this time. During the Holocene, dissimilar climate trends point to reduced influence of the Alaskan Stream in the northwest Pacific.

  9. Estimation of matter fluxes in the river-sea and ocean-atmosphere systems for Okhotsk and Bering seas

    International Nuclear Information System (INIS)

    The matter fluxes from continental and anthropogenic sources to sea take place by river discharge and atmospheric precipitation. The estimation of this flux may be done on the basis of a single concept, but it has its own specific character in both cases: (1) the time-space changeability of the matter distribution in sea components is connected with the complex gradients of hydrophysical, physico-chemical and hydrobiological characteristics of the water mass, by name biological barrier; (2) the altitude and stability of this biogeochemical barrier are determined by short-period (from seconds up to one year) geochemical processes; and (3) it is very interesting and important to estimate not only the matter fluxes on the continent under the motion of water and air, but also the intensity of accumulation on the biogeochemical barrier. It is necessary to do the next complex of investigations on the coast and aquatory of the Okhotsk and Bering Seas. This will include: (1) the synchronous registration of physical, chemical and biological characteristics in the river-sea and ocean- atmosphere systems to determine the transport and transformation of existing forms of matter, (2) observations of the distribution of natural and pollutant matter (such as heavy metals, oil and polycyclic aromatic hydrocarbons, artificial radioisotopes, etc.) in the estuaries, atmosphere, shelf zones and open sea regions; and (3) calculations of the matter fluxes between the different components of the sea

  10. Radiolaria fossils in the surface sediments and sedimentary environment in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Totally 2472 grains of Radiolaria belonging to 36 Genera and 45 species are distinguished from 12 surface sediments in the Bering Sea. The distribution characteristics of Radiolaria fossils in the surface sediments are as follows: (1) From the shelf of shallow water to the upper of continental slope, there are a few Radiolaria fossils and monotonous genus and species; (2) In the lower of continental slope, Radiolaria fossils are poor in the volcanic cinders and turbidite; (3) The abundance and diversity of Radiolaria fossils are high in clay of the basin. The dominant species of Radiolaria is Spongotrochus glacialis on the continental shelf. Current, topography, water depth, and temperature etc. are key factors influencing Radiolaria distribution. The sources of sediments mainly are terrigenous, biogenic and volcanic sediments in the survey area and they are mostly from the Kamchatka peninsula in the east of Russia and the Aleutian Islands.

  11. Modeling haul-out behavior of walruses in Bering Sea ice

    Science.gov (United States)

    Udevitz, M.S.; Jay, C.V.; Fischbach, A.S.; Garlich-Miller, J. L.

    2009-01-01

    Understanding haul-out behavior of ice-associated pinnipeds is essential for designing and interpreting popula-tion surveys and for assessing effects of potential changes in their ice environments. We used satellite-linked transmitters to obtain sequential information about location and haul-out state for Pacific walruses, Odobenus rosmarus divergens (Il-liger, 1815), in the Bering Sea during April of 2004, 2005, and 2006. We used these data in a generalized mixed model of haul-out bout durations and a hierarchical Bayesian model of haul-out probabilities to assess factors related to walrus haul-out behavior, and provide the first predictive model of walrus haul-out behavior in sea ice habitat. Average haul-out bout duration was 9 h, but durations of haul-out bouts tended to increase with durations of preceding in-water bouts. On aver-age, tagged walruses spent only about 17% of their time hauled out on sea ice. Probability of being hauled out decreased with wind speed, increased with temperature, and followed a diurnal cycle with the highest values in the evening. Our haul-out probability model can be used to estimate the proportion of the population that is unavailable for detection in spring surveys of Pacific walruses on sea ice.

  12. Climate program "stone soup": Assessing climate change vulnerabilities in the Aleutian and Bering Sea Islands of Alaska

    Science.gov (United States)

    Littell, J. S.; Poe, A.; van Pelt, T.

    2015-12-01

    Climate change is already affecting the Bering Sea and Aleutian Island region of Alaska. Past and present marine research across a broad spectrum of disciplines is shedding light on what sectors of the ecosystem and the human dimension will be most impacted. In a grassroots approach to extend existing research efforts, leveraging recently completed downscaled climate projections for the Bering Sea and Aleutian Islands region, we convened a team of 30 researchers-- with expertise ranging from anthropology to zooplankton to marine mammals-- to assess climate projections in the context of their expertise. This Aleutian-Bering Climate Vulnerability Assessment (ABCVA) began with researchers working in five teams to evaluate the vulnerabilities of key species and ecosystem services relative to projected changes in climate. Each team identified initial vulnerabilities for their focal species or services, and made recommendations for further research and information needs that would help managers and communities better understand the implications of the changing climate in this region. Those draft recommendations were shared during two focused, public sessions held within two hub communities for the Bering and Aleutian region: Unalaska and St. Paul. Qualitative insights about local concerns and observations relative to climate change were collected during these sessions, to be compared to the recommendations being made by the ABCVA team of researchers. Finally, we used a Structured Decision Making process to prioritize the recommendations of participating scientists, and integrate the insights shared during our community sessions. This work brought together residents, stakeholders, scientists, and natural resource managers to collaboratively identify priorities for addressing current and expected future impacts of climate change. Recommendations from this project will be incorporated into future research efforts of the Aleutian and Bering Sea Islands Landscape Conservation

  13. Corrigendum to ''Climate-mediated changes in zooplankton community structure for the eastern Bering Sea'' [Deep-Sea Res. II 109 (2014) 157-171

    Science.gov (United States)

    Eisner, L. B.; Napp, J. M.; Mier, K. L.; Pinchuk, A. I.; Andrews, A. G.

    2016-10-01

    The authors regret that the panels are mislabelled in the caption for Fig. 7. The caption should read, "Untransformed mean zooplankton abundances in the eastern Bering Sea for large taxa in the (A) north (~60-63°N) and (B) south (<~60°N) and for small taxa in the (C) north and (D) south. Bar indicates warm and cold regimes".

  14. A coupled ice-ocean ecosystem model for 1-D and 3-D applications in the Bering and Chukchi Seas

    Institute of Scientific and Technical Information of China (English)

    Jin Meibing; Clara Deal; WANG Jia

    2008-01-01

    Primary production in the Bering and Chukchi Seas is strongly influenced by the annual cycle of sea ice. Here pelagic and sea ice algal ecosystems coexist and interact with each other. Ecosystem modeling of sea ice associated phytoplankton blooms has been understudied compared to open water ecosystem model applications.This study introduces a general coupled ice-ocean ecosystem model with equations and parameters for 1-D and 3-D applications that is based on 1-D coupled ice-ocean ecosystem model development in the landfast ice in the Chukchi Sea and marginal ice zone of Bering Sea. The biological model includes both pelagic and sea ice algal habitats with 10 compartments: three phytoplankton (pelagic diatom, flagellates and ice algae: D, F, and Ai), three zooplankton (copepods, large zooplankton, and microzooplankton: ZS, ZL, ZP), three nutrients (nitrate + nitrite, ammonium, silicon:NO3, NH4, Si) and detritus (Det). The coupling of the biological models with physical ocean models is straightforward with just the addition of the advection and diffusion terms to the ecosystem model. The coupling with a multi-category sea ice model requires the same calculation of the sea ice ecosystem model in each ice thickness category and the redistribution between categories caused by both dynamic and thermodynamic forcing as in the physical model. Phytoplankton and ice algal self-shading effect is the sole feedback from the ecosystem model to the physical model.

  15. Summertime atmosphere-ocean preconditionings for the Bering Sea ice retreat and the following severe winters in North America

    Science.gov (United States)

    Nakanowatari, Takuya; Inoue, Jun; Sato, Kazutoshi; Kikuchi, Takashi

    2015-09-01

    Atmospheric responses to sea ice retreat in the Bering Sea have been linked to recent extreme winters in North America. We investigate the leading factor for the interannual variability of Bering sea ice area (SIA) in early winter (November-December), using canonical correlation analysis based on seasonally resolved atmosphere and ocean data for 1980-2014. We found that the 3-month leading (August-September) geopotential height at 500 hPa (Z500) in the Northern Hemisphere explains 29% of SIA variability. The spatial pattern of Z500 for positive (negative) sea ice anomalies is associated with negative (positive) anomalies over the Gulf of Alaska related to the Pacific transition (PT) pattern. The heat budget analysis indicates that summertime atmospheric conditions influence SIA through the ocean temperature anomalies of the Alaskan Coastal Current forced by atmospheric turbulent heat fluxes. The PT pattern highly correlates with convective precipitation in the western subtropical Pacific, implying that weakened subtropical forcing is the likely cause for the recent extreme winters in North America. Our results present a major factor for interannual variability in the Bering SIA, and further would contribute to the improvement of forecasting winter climate in North America.

  16. The level and bioaccumulation of Cd, Cu, Cr and Zn in benthopelagic species from the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    SHI Ronggui; LIN Jing; YE Yi; MA Yifan; CAI Minggang

    2015-01-01

    The Bering Sea is an area of high biological productivity, with large populations of sea-birds, demersal and pelagic fishes, so it seemed desirable to assess the bioaccumulation of trace metals in the marine organisms from this area. However, few data on trace metal concentrations are available for the benthopelagic organisms from the Bering Sea till now. Ten specimens of benthos (including 120 biological samples) were collected in the western Bering Sea in August 2008 during the 3rd Chinese National Arctic Research Expeditions, and the concentration of Cd, Cu, Cr and Zn determined using atomic absorption spectrometry. Zn, Cr and Cd concentrations in muscle tissues of the crab species were much higher than those from fish and cephalopod species, and the highest concentration of Cu was observed in the muscle tissues ofCylichna nucleoli. The results showed a similar hierarchy for Zn, Cr, Cd and Cu concentrations among different tissues as follows: hepatopancreas>muscle tissue>gonad. Bioconcentration factors indicated that benthic organisms had high accumulation abilities for Zn and Cu.

  17. High-resolution IP25-based reconstruction of sea-ice variability in the western North Pacific and Bering Sea during the past 18,000 years

    Science.gov (United States)

    Méheust, Marie; Stein, Ruediger; Fahl, Kirsten; Max, Lars; Riethdorf, Jan-Rainer

    2016-04-01

    Due to its strong influence on heat and moisture exchange between the ocean and the atmosphere, sea ice is an essential component of the global climate system. In the context of its alarming decrease in terms of concentration, thickness and duration, understanding the processes controlling sea-ice variability and reconstructing paleo-sea-ice extent in polar regions have become of great interest for the scientific community. In this study, for the first time, IP25, a recently developed biomarker sea-ice proxy, was used for a high-resolution reconstruction of the sea-ice extent and its variability in the western North Pacific and western Bering Sea during the past 18,000 years. To identify mechanisms controlling the sea-ice variability, IP25 data were associated with published sea-surface temperature as well as diatom and biogenic opal data. The results indicate that a seasonal sea-ice cover existed during cold periods (Heinrich Stadial 1 and Younger Dryas), whereas during warmer intervals (Bølling-Allerød and Holocene) reduced sea ice or ice-free conditions prevailed in the study area. The variability in sea-ice extent seems to be linked to climate anomalies and sea-level changes controlling the oceanographic circulation between the subarctic Pacific and the Bering Sea, especially the Alaskan Stream injection though the Aleutian passes.

  18. Linkages between sea-ice coverage, pelagic-benthic coupling, and the distribution of spectacled eiders: Observations in March 2008, 2009 and 2010, northern Bering Sea

    Science.gov (United States)

    Cooper, L. W.; Sexson, M. G.; Grebmeier, J. M.; Gradinger, R.; Mordy, C. W.; Lovvorn, J. R.

    2013-10-01

    Icebreaker-based sampling in the northern Bering Sea south of St. Lawrence Island in March of 2008, 2009, and 2010 has provided new data on overall ecosystem function early in the annual productive cycle. While water-column chlorophyll concentrations (5 µM. These data, together with other physical, biological, and nutrient data, are presented here in conjunction with observed sea-ice dynamics and the distribution of an apex predator, the Spectacled Eider (Somateria fischeri). Sea-ice dynamics in addition to benthic food availability, as determined by sedimentation processes, play a role in the distribution of spectacled eiders, which cannot always access the greatest biomass of their preferred bivalve prey. Overall, the data and observations indicate that the northern Bering Sea is biologically active in late winter, but with strong atmospheric and hydrographic controls. These controls pre-determine nutrient and chlorophyll distributions, water-column mixing, as well as pelagic-benthic coupling.

  19. Distribution of fish and macrozooplankton in ice-covered and open-water areas of the eastern Bering Sea

    Science.gov (United States)

    De Robertis, Alex; Cokelet, Edward D.

    2012-06-01

    The eastern Bering Sea shelf is a productive ecosystem with extensive commercial fisheries. Although the area is well-studied during summer months, little is known about the abundance and distribution of fish and macrozooplankton during periods of seasonal ice cover. The use of an icebreaker during the Bering Sea Ecosystem Study (BEST) provided a platform for spring acoustic surveys of fish and zooplankton in ice-covered areas for the first time. Icebreaker measurements were complemented with observations from conventional vessels during spring and summer. In spring, very little backscatter from fish (dominated by walleye pollock, Theragra chalcogramma) was observed in the ice-covered northern areas where near-bottom waters were cold (cannibalism.

  20. Airborne Remote Sensing of a Biological Hot Spot in the Southeastern Bering Sea

    Directory of Open Access Journals (Sweden)

    Michael F. Sigler

    2011-03-01

    Full Text Available Intense, ephemeral foraging events within localized hot spots represent important trophic transfers to top predators in marine ecosystems, though the spatial extent and temporal overlap of predators and prey are difficult to observe using traditional methods. The southeastern Bering Sea has high marine productivity along the shelf break, especially near marine canyons. At a hot spot located near Bering Canyon, we observed three foraging events over a 12 day period in June 2005. These were located by aerial surveys, quantified by airborne lidar and visual counts, and characterized by ship-based acoustics and net catches. Because of the high density of seabirds, the events could be seen in images from space-based synthetic aperture radar. The events developed at the shelf slope, adjacent to passes between the Aleutian Islands, persisted for 1 to 8 days, then abruptly disappeared. Build-up and break down of the events occurred on 24 hr time scales, and diameters ranged from 10 to 20 km. These events comprised large concentrations of euphausiids, copepods, herring, other small pelagic fishes, humpback whales, Dall’s porpoise, short-tailed shearwaters, northern fulmars, and other pelagic seabirds. The lidar and acoustic remote sensing data demonstrated that prey densities inside the events were several times higher than those outside, indicating the importance of including events in forage fish surveys. This implies a need for either very intensive traditional surveys covering large expanses or for adaptive surveys guided by remote sensing. To our knowledge, this is the first time that an Alaskan hot spot was monitored with the combination of airborne and satellite remote sensing.

  1. Foraging segregation of two congeneric diving seabird species breeding on St. George Island, Bering Sea

    Science.gov (United States)

    Kokubun, Nobuo; Yamamoto, Takashi; Sato, Nobuhiko; Watanuki, Yutaka; Will, Alexis; Kitaysky, Alexander S.; Takahashi, Akinori

    2016-04-01

    Subarctic environmental changes are expected to affect the foraging ecology of marine top predators, but the response to such changes may vary among species if they use food resources differently. We examined the characteristics of foraging behavior of two sympatric congeneric diving seabird: common (Uria aalge: hereafter COMUs) and thick-billed (U. lomvia: hereafter TBMUs) murres breeding on St. George Island, located in the seasonal sea-ice region of the Bering Sea. We investigated their foraging trip and flight durations, diel patterns of dive depth, and underwater wing strokes, along with wing morphology and blood stable isotope signatures and stress hormones. Acceleration-temperature-depth loggers were attached to chick-guarding birds, and data were obtained from 7 COMUs and 12 TBMUs. Both species showed similar mean trip duration (13.2 h for COMUs and 10.5 h for TBMUs) and similar diurnal patterns of diving (frequent dives to various depths in the daytime and less frequent dives to shallow depths in the nighttime). During the daytime, the dive depths of COMUs had two peaks in shallow (18.1 m) and deep (74.2 m) depths, while those of TBMUs were 20.2 m and 59.7 m. COMUs showed more frequent wing strokes during the bottom phase of dives (1.90 s-1) than TBMUs (1.66 s-1). Fish occurred more frequently in the bill loads of COMUs (85 %) than those of TBMUs (56 %). The δ15N value of blood was significantly higher in COMUs (14.5 ‰) than in TBMUs (13.1 ‰). The relatively small wing area (0.053 m2) of COMUs compared to TBMUs (0.067 m2) may facilitate their increased agility while foraging and allow them to capture more mobile prey such as larger fishes that inhabit deeper depths. These differences in food resource use may lead to the differential responses of the two murre species to marine environmental changes in the Bering Sea.

  2. Assigning king eiders to wintering regions in the Bering Sea using stable isotopes of feathers and claws

    Science.gov (United States)

    Oppel, S.; Powell, A.N.

    2008-01-01

    Identification of wintering regions for birds sampled during the breeding season is crucial to understanding how events outside the breeding season may affect populations. We assigned king eiders captured on breeding grounds in northern Alaska to 3 broad geographic wintering regions in the Bering Sea using stable carbon and nitrogen isotopes obtained from head feathers. Using a discriminant function analysis of feathers obtained from birds tracked with satellite transmitters, we estimated that 88 % of feathers were assigned to the region in which they were grown. We then assigned 84 birds of unknown origin to wintering regions based on their head feather isotope ratios, and tested the utility of claws for geographic assignment. Based on the feather results, we estimated that similar proportions of birds in our study area use each of the 3 wintering regions in the Bering Sea. These results are in close agreement with estimates from satellite telemetry and show the usefulness of stable isotope signatures of feathers in assigning marine birds to geographic regions. The use of claws is currently limited by incomplete understanding of claw growth rates. Data presented here will allow managers of eiders, other marine birds, and marine mammals to assign animals to regions in the Bering Sea based on stable isotope signatures of body tissues. ?? Inter-Research 2008.

  3. Dynamical analysis of a satellite-observed anticyclonic eddy in the northern Bering Sea

    Science.gov (United States)

    Li, Yineng; Li, Xiaofeng; Wang, Jia; Peng, Shiqiu

    2016-05-01

    The characteristics and evolution of a satellite-observed anticyclonic eddy in the northern Bering Sea during March and April 1999 are investigated using a three-dimensional Princeton Ocean Model (POM). The anticyclonic-like current pattern and asymmetric feature of the eddy were clearly seen in the synthetic aperture radar (SAR), sea surface temperature, and ocean color images in April 1999. The results from model simulation reveal the three-dimensional structure of the anticyclonic eddy, its movement, and dissipation. Energy analysis indicates that the barotropic instability (BTI) is the main energy source for the growth of the anticyclonic eddy. The momentum analysis further reveals that the larger magnitude of the barotropic pressure gradient in the meridional direction causes the asymmetry of the anticyclonic eddy in the zonal and meridional directions, while the different magnitudes of the meridional baroclinic pressure gradient are responsible for the different intensity of currents between the northern and southern parts of the anticyclonic eddy. This article was corrected on 23 JUL 2016. See the end of the full text for details.

  4. Oceanic environmental changes of subarctic Bering Sea in recent 100 years: Evidence from molecular fossils

    Institute of Scientific and Technical Information of China (English)

    LU; Bing; CHEN; Ronghua; ZHOU; Huaiyang; WANG; Zipan; CHEN

    2005-01-01

    The core sample B2-9 from the seafloor of the subarctic Bering Sea was dated with 210Pb to obtain a consecutive sequence of oceanic sedimentary environments at an interval of a decade during 1890-1999. A variety of molecular fossils were detected, including n-alkanes, isoprenoids, fatty acids, sterols, etc. By the characteristics of these fine molecules (C27, C28, and C29 sterols) and their molecular indices (Pr/Ph, ∑C+22/∑C?21, CPI and C18∶2/C18∶0) and in consideration of the variation of organic carbon content, the 100-year evolution history of subarctic sea paleoenvironment was reestablished. It is indicated that during the past 100 years in the Arctic, there were two events of strong climate warming (1920-1950 and 1980-1999), which resulted in an oxidated sediment environment owing to decreasing terrigenous organic matters and increasing marine-derived organic matters, and two events of transitory climate cooling (1910 and 1970-1980), which resulted in a slightly reduced sediment environment owing to increasing terrigenous organic matters and decreasing marine-derived organic matters. It is revealed that the processes of warming/cooling alternated climate are directly related to the Arctic and global climate variations.

  5. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

    Science.gov (United States)

    Sasaki, H.; Matsuno, K.; Fujiwara, A.; Onuka, M.; Yamaguchi, A.; Ueno, H.; Watanuki, Y.; Kikuchi, T.

    2015-11-01

    The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

  6. Origins of the subsurface ammonium maximum in the Southeast Bering Sea

    Science.gov (United States)

    Mordy, Calvin W.; Stabeno, Phyllis J.; Righi, Dylan; Menzia, Frederick A.

    2008-08-01

    In the Bering Sea, it has long been argued that ammonium-rich bottom water from the middle shelf of Bristol Bay is tidally diffused seaward resulting in a mid-depth ammonium tongue over the outer shelf. Weak horizontal mean flows in the region (relative to an especially strong tidal component) support this contention. We examined the distribution of ammonium further north in the vicinity of the Pribilof Islands. On the middle shelf, bottom waters had concentrations of 4-7 μmol kg -1, and over the outer shelf there was a mid-depth ammonium tongue. Optimal multiparameter analysis of hydrographic data suggested that bottom waters from the middle shelf were prevalent across the outer shelf, and could account for this ammonium tongue. Drifter tracks demonstrated that middle shelf water was incorporated into a westward flow along the shelf break south of St. George Island, and mean flows derived from several decades of drifter tracks also show prominent cross-shelf advection in the region. This was consistent with a scalar argument suggesting that, in the vicinity of the Pribilof Islands, the seaward movement of middle shelf water, and loss of nitrogen over the middle shelf, was the result of advection rather than tidally driven lateral diffusion.

  7. Potential effects of temperature on the benthic infaunal community on the southeastern Bering Sea shelf: Possible impacts of climate change

    Science.gov (United States)

    Coyle, K. O.; Konar, B.; Blanchard, A.; Highsmith, R. C.; Carroll, J.; Carroll, M.; Denisenko, S. G.; Sirenko, B. I.

    2007-11-01

    In the late 1950s, Soviet researchers collected benthic infaunal samples from the southeastern Bering Sea shelf. Approximately 17 years later, researchers at University of Alaska Fairbanks also sampled the region to assess infaunal biomass and abundance. Here, the two data sets were examined to document patterns and reveal any consistent differences in infaunal biomass among major feeding groups between the two time periods. No significant differences in the geometric mean biomass of all taxa pooled were indicated between the two study periods (1958-1959=49.1 g m -2; 1975-1976=60.8 g m -2; P=0.14); however, significant differences were observed for specific functional groups, namely carnivores, omnivores and surface detritivores. Of the 64 families identified from both data sets from all functional groups, 21 showed statistically significant ( P⩽0.05) differences in mean biomass. Of the 21 families showing significant differences, 19 (91%) of the families had higher mean biomass in the 1975-1976 data set. The above differences suggest a trend toward higher overall infaunal biomass for specific functional groups during mid 1970s compared with the late 1950s. Temperature measurements and literature data indicate that the mid-1970s was an unusually cold period relative to the period before and after, suggesting a mechanistic link between temperature changes and infaunal biomass. Food-web relationships and ecosystem dynamics in the southeastern Bering Sea indicate that during cold periods, infaunal biomass will be elevated relative to warm periods due to elevated carbon flux to the benthos and exclusion of benthic predators on infaunal invertebrates by the cold bottom water on the shelf. As long-term observations of temperature and sea-ice cover indicate a secular warming trend on the Bering Sea shelf, the potential changes in food-web relationships could markedly alter trophic structure and energy flow to apex consumers, potentially impacting the commercial, tourist

  8. A sequential method of detecting abrupt changes in the correlation coefficient and its application to Bering Sea climate

    CERN Document Server

    Rodionov, Sergei

    2015-01-01

    A new method of regime shift detection in the correlation coefficient is proposed. The method is designed to find multiple change-points with unknown locations in time series. It signals a possible regime shift in real time and allows for its monitoring. The method is tested on randomly generated time series with predefined change-points. It is applied to examine structural changes in the Bering Sea climate. A major shift is found in 1967, which coincides with a transition from a zonal type of atmospheric circulation to a meridional one. The most recent shift has occurred in 2004, but it still needs to be monitored.

  9. Late Quaternary Provenance and Flow Regime Reconstruction through Sedimentologic and Geochemical Evidence from the Bering/Chukchi Seas

    Science.gov (United States)

    Pelto, B. M.; Brigham-Grette, J.; Kocis, J. J.; Petsch, S.

    2013-12-01

    The last 20 kyr have been marked by great changes in the Arctic, as the Laurentide Ice Sheet melted and led to the submergence of the Bering Land Bridge and the re-opening of the Bering Strait (BS). The BS is a narrow connection (about 85 km wide) between the Arctic and Pacific Oceans averaging less than 50 m in depth, with present-day flow of seawater northward through the BS, from the Pacific to the Arctic. This flow is of vital importance to global ocean circulation through its role in formation and stability of North Atlantic Deep Water (NADW). An open BS is believed to speed dispersal of North Atlantic freshwater anomalies, both by keeping thermohaline circulation strong, and through reversals of flow through the BS when the North Atlantic is hosed with freshwater. When the BS is closed, these anomalies cannot efficiently dissipate and thermohaline circulation is weakened, which is considered a factor in climate perturbations outside of orbital forcing. Given the period of flux and transition in the Arctic following the Last Glacial Maximum (LGM), the paleoceanographic history of the Bering and Chukchi Seas post-LGM, is important to an understanding of Arctic Ocean circulation, and consequent climate impacts. Today the Arctic is in a period of rapid change, multi-year sea ice is disappearing, and the continuation of climatic stability of the Holocene appears to be at an end. Comprehension of the functioning of the Arctic as a dynamic system is essential to predict future response of the system to change, such as seawater salinity-density changes, lowered sea and land albedo, and rising temperatures. Changes in BS throughflow intensity and direction during deglaciation and submergence of the Bering Land Bridge are proposed and supported in modeling simulations, and are thought to occur during millennial-scale climate changes. We have conducted a coupled sedimentological and geochemical investigation of a suite of marine sediment cores from the Bering and

  10. Ophiacantha clypeata n. sp. from the Bering Sea, with a redescription of Ophiacantha rhachophora Clark (Echinodermata: Ophiuroidea)

    Energy Technology Data Exchange (ETDEWEB)

    Kyte, M.A.

    1977-06-16

    Ophiacantha clypeata differs from O. rhachophora in having the distal tips of the radial shields concealed, the basal upper arm plates with thorny stumps, small and inconspicuous genital slits, oral shields quadrangular and wider than long, first lateral arm shields and oral shields contiguous, not separated by the aboral plates, arm spines on the first basal segment not meeting on the aboral side of the arm segment, and entirely smooth uppermost arm spines. While the oral papillae of O. rhachophora are markedly thorny, the 6 to 10 papillae of O. clypeata are only slightly serrate. A papilla does not arise from the adoral shield in O. clypeata. Geographical distribution supports the evidence from morphological differences. While O. clypeata occurs only in the Bering Sea, O. rhachophora is apparently restricted to Japanese waters and the Eastern Sea (Clark, 1911; Matsumoto, 1917). Although the depth ranges of the 2 species overlap, O. rhachophora is found in somewhat shallower water than O. clypeata This geographical separation and the morphological differences indicate clearly that Clark's (1911) Bering Sea specimens of O. rhachophora should be separated as a distinct species.

  11. A Pliocene to recent history of the Bering Sea at Site U1340A, IODP Expedition 323

    Science.gov (United States)

    Stroynowski, Zuzia; Ravelo, Anna Christina; Andreasen, Dyke

    2015-12-01

    Fossil diatoms are the principal component of Bering Sea sediments and reflect the paleoceanographic history of the region. Diatom accumulation rates and relative abundances at International Ocean Discovery Program (IODP) Site U1340A are presented. Overall, the total diatom productivity record from 4.9 Ma to the present day reveals a fourfold reduction at circa 4.2 Ma from ~45 × 107 down to 11 × 107 valves/g (wet sediment), signifying a major shift in the upwelling and/or nutrient regime, coinciding with the end of the late Miocene-early Pliocene bloom identified in the eastern equatorial Pacific and California margin. Further abrupt shifts in the diatom assemblage occur at (1) 2.78-2.55 Ma, (2) 2.0-1.8 Ma, and (3) 1.0-0.88 Ma. (1) At 2.78-2.55 Ma, the appearance of sea ice-related species marks the regional cooling associated with the expansion of Northern Hemisphere ice sheets, subsequent development of stratified, nutrient-depleted waters, and increased influence of Western Basin Water masses (most likely due to the suppressed inflow of the Alaskan Stream). (2) Rapid cooling between 2.0 and 1.8 Ma indicates increased sea ice duration and/or frequency. This, coupled with low sea level stands caused prolonged closure of the Aleutian Passes, coupled with further increased Western Basin Water inflow. (3) The shift to 100 ka glacial/interglacial cycles at the middle-Pleistocene transition (1.0-0.88 Ma) marked an increase in upwelling-related species, indicating enhanced surface water mixing. These records confirm that the development and changing dynamics of sea ice in the Bering Sea played a major role in sub-Arctic Ocean circulation and is an integral component of global climate change.

  12. A shape and compositional analysis of ice-rafted debris in cores from IODP Expedition 323 in the Bering Sea

    Science.gov (United States)

    Dadd, Kelsie; Foley, Kristen

    2016-03-01

    Sediment cores recovered during IODP Expedition 323 in the Bering Sea, northern Pacific, contained numerous ice-rafted debris (IRD) clasts up to 85 mm in length. The physical properties (including roundness and sphericity) of 136 clasts from the working half of the cores, a subsample of the total clast number, were analysed and their composition determined using standard petrographic techniques. After removal of pumice and possible fall-in derived material from the clast population, a total of 86 clasts from the original collection were considered to be IRD. While roundness and sphericity vary greatly in the clast population, the IRD are predominately discoid in shape with oblate/prolate indices typically between -5 and 5. There are four time periods over the approximately 4.5 Ma sample interval, 0.36-0.67 Ma, 0.82-1.06 Ma 1.54-1.77 Ma and >3.28 Ma, where there are no IRD in the sample set for sites of the Bering slope, suggesting that these times may have been ice-free. Most clasts show some rounding and are likely to have spent time on beaches with wave action. Wave action on beaches suggests periods of no ice or only seasonal sea-ice. The low roundness values of other clasts, however, suggest they underwent little working and, therefore, the presence of glaciers or more permanent sea-ice at times in those locations. The abundance of rounded and unfaceted clasts as IRD suggests a lack of large ice sheets in the area during cool periods. Clast composition of the IRD is divided into four broad groups, basalt and andesite, granite and metamorphic, sedimentary, and felsic volcanic. The granite and metamorphic and more mature sedimentary lithologies are most likely derived from the Alaskan continental margin, while the extrusive igneous clasts could be derived from a variety of volcanic sources surrounding the Bering Sea, both emergent now or emergent at times of lower sea level. There is only a poor correlation with IRD abundance and marine isotope stages (MIS) for

  13. Bering Sea radiolarian biostratigraphy and paleoceanography at IODP Site U1341 during the last four million years

    Science.gov (United States)

    Ikenoue, Takahito; Okazaki, Yusuke; Takahashi, Kozo; Sakamoto, Tatsuhiko

    2016-03-01

    Radiolarian assemblages in sediment cores were investigated at the Integrated Ocean Drilling Program Site U1341 on Bowers Ridge in the southern Bering Sea. Radiolarian biozones at Site U1341 spanned the last 4 My from the youngest Amphimelissa setosa Zone (late Quaternary), via the Stylatractus universes Zone, the Eucyrtidium matuyamai Zone and a part of the Cycladophora sakaii Zone (middle to late Pliocene). The A. setosa Zone, newly proposed in this paper, is well correlated with the Botryostrobus aquilonaris Zone in the North Pacific Ocean. The bottom of the S. universus and top of the E. matuyamai Zones are emended in this paper by using the first common occurrence of A. setosa. Seventeen radiolarian datum points were identified at Site U1341 and tied to the geomagnetic and oxygen isotope stratigraphy. Radiolarian assemblages during the last 4 My showed a turnover from subarctic-transitional species (Spongopyle osculosa and Larcopyle buetschlii) to subarctic species (Ceratospyris borealis) between 3.6 and 2.4 Ma, corresponding to the intensification of the Northern Hemisphere Glaciation (NHG). Recent polar species (A. setosa and Actinomma boreale) appeared abundantly after the Mid-Pleistocene Transition (MPT, 1.2-0.8 Ma). Repeated numbers of individual peaks of the abundances of Cycladophora davisiana, dwelling in cold and well-ventilated intermediate water, suggest intermediate to deep water formation in the Bering Sea during the last 1 My.

  14. Remote sensing of size structure of phytoplankton communities using optical properties of the Chukchi and Bering Sea shelf region

    Science.gov (United States)

    Fujiwara, A.; Hirawake, T.; Suzuki, K.; Saitoh, S.-I.

    2011-12-01

    Recent ocean warming and subsequent sea ice decline resulting from climate change could affect the northward shift of the ecosystem structure in the Chukchi Sea and Bering Sea shelf region (Grebmeier et al., 2006b). The size structure of phytoplankton communities provides an index of trophic levels that is crucial to understanding the mechanisms underlying such ecosystem changes and their implications for the future. This study proposes a new ocean color algorithm for deriving this characteristic by using the region's optical properties. The size derivation model (SDM) estimates the phytoplankton size index FL on the basis of size-fractionated chlorophyll-a (chl-a) using the light absorption coefficient of phytoplankton, aph(λ), and the backscattering coefficient of suspended particles including algae, bbp(λ). FL was defined as the ratio of algal biomass attributed to cells larger than 5 μm to the total. It was expressed by a multiple regression model using the aph(λ) ratio, aph(488)/aph(555), which varies with phytoplankton pigment composition, and the spectral slope of bbp(λ), γ, which is an index of the mean suspended particle size. A validation study demonstrated that 69% of unknown data are correctly derived within FL range of ±20%. The spatial distributions of FL for the cold August of 2006 and the warm August of 2007 were compared to examine application of the SDM to satellite remote sensing. The results suggested that phytoplankton size was responsive to changes in sea surface temperature. Further analysis of satellite-derived FL values and other environmental factors can advance our understanding of ecosystem structure changes in the shelf region of the Chukchi and Bering Seas.

  15. Millennial-scale variability of marine productivity and terrigenous matter supply in the western Bering Sea over the past 180 kyr

    Directory of Open Access Journals (Sweden)

    J.-R. Riethdorf

    2012-12-01

    Full Text Available We used piston cores recovered in the western Bering Sea to reconstruct millennial-scale changes in marine productivity and terrigenous matter supply over the past ~180 kyr. Based on a geochemical multi-proxy approach our results indicate closely interacting processes controlling marine productivity and terrigenous matter supply comparable to the situation in the Okhotsk Sea. Overall, terrigenous inputs were high, whereas primary production was low. Minor increases in marine productivity occurred during warm intervals of stage 5 and interstadials, but pronounced maxima were recorded during interglacials and Termination I. Seasonal sea-ice is suggested to act as the dominant transport agent for terrigenous material. From our results we propose glacial, deglacial, and interglacial scenarios for environmental change in the Bering Sea. These changes seem to be primarily controlled by insolation and sea-level forcing which affect the strength of atmospheric pressure systems and sea-ice growth. The opening history of the Bering Strait and the Aleutian passes is considered to have had an additional impact. Sea-ice dynamics are thought to drive changes in surface productivity, terrigenous inputs, and upper-ocean stratification. High-resolution core logging data (color b*, XRF scans strongly correspond to the Dansgaard–Oeschger climate variability registered in the NGRIP ice core and support an atmospheric coupling mechanism of Northern Hemisphere climates.

  16. Linkages between sea-ice coverage, pelagic-benthic coupling, and the distribution of spectacled eiders: observations in March 2008, 2009 and 2010, northern Bering Sea

    Science.gov (United States)

    Cooper, L.W.; Sexson, M.G.; Grebmeier, J.M.; Gradinger, R.; Mordy, C.W.; Lovvorn, J.R.

    2013-01-01

    Icebreaker-based sampling in the northern Bering Sea south of St. Lawrence Island in March of 2008, 2009, and 2010 has provided new data on overall ecosystem function early in the annual productive cycle. While water-column chlorophyll concentrations (−2 integrated over the whole water column) are two orders of magnitude lower than observed during the spring bloom in May, sea-ice algal inventories of chlorophyll are high (up to 1 g m−3 in the bottom 2-cm of sea-ice). Vertical fluxes of chlorophyll as measured in sediment traps were between 0.3 to 3.7 mg m−2 d−1 and were consistent with the recent deposition (days to weeks time scale) of chlorophyll to the surface sediments (0–25 mg m−2 present at 0–1 cm). Sediment oxygen respiration rates were lower than previous measurements that followed the spring bloom, but were highest in areas of known high benthic biomass. Early spring release of sedimentary ammonium occurs, particularly southeast of St. Lawrence Island, leading to bottom-water ammonium concentrations of >5 µM. These data, together with other physical, biological, and nutrient data are presented here in conjunction with observed sea-ice dynamics and the distribution of an apex predator, the Spectacled Eider (Somateria fischeri). Sea-ice dynamics in addition to benthic food availability, as determined by sedimentation processes, play a role in the distribution of spectacled eiders, which cannot always access the greatest biomass of their preferred bivalve prey. Overall, the data and observations indicate that the northern Bering Sea is biologically active in late winter, but with strong atmospheric and hydrographic controls. These controls pre-determine nutrient and chlorophyll distributions, water-column mixing, as well as pelagic-benthic coupling.

  17. Drifting buoy and other data from the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 13 September 1975 to 25 September 1975 (NODC Accession 7600632)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifting buoy data was collected from the Bering Sea by the Atlantic Oceanographic and Meteorological Laboratory (AOML) as part of the Outer Continental Shelf...

  18. Drifting buoy and other data from the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 27 May 1977 to 07 January 1978 (NODC Accession 7800692)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifting buoy data was collected from the Bering Sea by the Atlantic Oceanographic and Meteorological Laboratory (AOML) as part of the Outer Continental Shelf...

  19. l576bs.m77t - MGD77 data file for Geophysical data from field activity L-5-76-BS in Southern Bering Sea Shelf from 07/28/1976 to 08/25/1976

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-5-76-BS in Southern Bering Sea Shelf...

  20. l1082bs.m77t - MGD77 data file for Geophysical data from field activity L-10-82-BS in Bering Sea, Alaska from 08/06/1982 to 08/24/1982

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-10-82-BS in Bering Sea, Alaska from...

  1. l877bs.m77t - MGD77 data file for Geophysical data from field activity L-8-77-BS in Bering Sea, Alaska from 07/29/1977 to 08/21/1977

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, magnetics, and gravity data along with transit satellite navigation data was collected as part of field activity L-8-77-BS in Bering Sea,...

  2. l478bs.m77t - MGD77 data file for Geophysical data from field activity L-4-78-BS in Bering Sea, Alaska from 07/08/1978 to 08/01/1978

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-4-78-BS in Bering Sea, Alaska from...

  3. l982bs.m77t - MGD77 data file for Geophysical data from field activity L-9-82-BS in Bering Sea, Alaska from 07/11/1982 to 08/03/1982

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, magnetics, and gravity data along with transit satellite navigation data was collected as part of field activity L-9-82-BS in Bering Sea,...

  4. Temperature and salinity profiles from STD casts in the Bering Sea from the SILAS BENT as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 01 September 1975 to 26 September 1975 (NODC Accession 7600747)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature and salinity profiles were collected from STD casts in the Bering Sea from the SILAS BENT. Data were collected by the University of Alaska - Fairbanks...

  5. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea from helicopters as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 08 February 1977 to 02 March 1977 (NODC Accession 7800004)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Bering Sea from helicopter. Data were collected by the University...

  6. Feeding flock and other data from ACONA and other platforms from the Bering Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 04 August 1975 to 16 September 1976 (NODC Accession 7700775)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Feeding flock and other data were collected from the ACONA and other platforms in the Bering Sea and other locations. Data were collected by Oregon State University...

  7. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea from the DISCOVERER as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 22 May 1977 to 09 June 1977 (NODC Accession 7700846)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Bering Sea from the DISCOVERER. Data were collected by the Pacific...

  8. Observations of carbon dioxide in the surface waters of the Eastern North Pacific Ocean and the Bering Sea from 21 July 1968 to 03 September 1968 (NODC Accession 7100114)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Measurements of the equilibrium concentration of carbon dioxide in the air and surface waters of the North Pacific Ocean and the Bering Sea are presented....

  9. NPRB 1117 Cooperative research to develop new trawl footrope designs to reduce mortality of southern Tanner and snow crabs (Chionoecetes bairdi and C. opilio) incidental to Bering Sea bottom trawl fisheries

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Alaska’s Bering Sea is home to some of the world’s most productive groundfish and crab stocks and the fisheries that depend on them. Their spatial overlap creates...

  10. Physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201504T in the Bering Sea, Gulf of Alaska and North Pacific Ocean from 2015-03-13 to 2015-03-18 (NCEI Accession 0145946)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0145946 includes physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201504T in the Bering Sea, Gulf of Alaska and...

  11. Temperature and salinity profiles from bottle and STD casts in the Bering Sea from the ACONA as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 02 July 1974 to 10 July 1974 (NODC Accession 7601138)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature and salinity profiles were collected from bottle and STD casts in the Bering Sea from the ACONA. Data were collected by the University of Alaska -...

  12. Marine bird sighting and other data from platform in the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 06 May 1976 to 19 August 1976 (NODC Accession 7700132)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from a platform in the Bering Sea from 06 May 1976 to 19 August 1976. Data were collected by the University of...

  13. Marine bird colony and other data from platforms in the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 15 June 1975 to 15 October 1976 (NODC Accession 7700654)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird colony and other data were collected from platforms in the Bering Sea from 15 June 1975 to 15 October 1976. Data were collected by the College of the...

  14. Marine bird sighting and other data from aircraft and other platforms from the Bering Sea and North Pacific as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 09 February 1976 to 01 October 1976 (NODC Accession 7800904)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from aircraft and other platforms in the Bering Sea and North Pacific. Data were collected by the Fish and...

  15. Benthic organism and other data from the MILLER FREEMAN from the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 02 April 1976 to 31 May 1976 (NODC Accession 7800537)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic organism and other data were collected in the Bering Sea from the MILLER FREEMAN by University of Alaska; Institute of Marine Science (UAK/IMS). Data were...

  16. Chemical, physical and underway data collected aboard the HEALY during cruise HLY11TC in the Bering Sea and North Pacific Ocean from 2011-06-12 to 2011-06-22 (NODC Accession 0103995)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0103995 includes chemical, physical and underway data collected aboard the HEALY during cruise HLY11TC in the Bering Sea and North Pacific Ocean from...

  17. AFSC/RACE/EcoFOCI: NPRB project number 926: Assessing the condition of walleye pollock, Theragra chalcogramma, larvae in the eastern Bering Sea with muscle-based flow cytometry cell cycle analysis

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Walleye pollock are an important component of the eastern Bering Sea ecosystem due to their vast numbers and biomass and are of great commercial importance. Their...

  18. Physical and underway data collected aboard the Marcus G. Langseth during cruise MGL1113 in the Bering Sea and North Pacific Ocean from 2011-10-12 to 2011-10-21 (NODC Accession 0104308)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104308 includes physical and underway data collected aboard the Marcus G. Langseth during cruise MGL1113 in the Bering Sea and North Pacific Ocean...

  19. Physical and underway data collected aboard the Marcus G. Langseth during cruise MGL1111 in the Bering Sea from 2011-08-07 to 2011-09-04 (NODC Accession 0104307)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104307 includes physical and underway data collected aboard the Marcus G. Langseth during cruise MGL1111 in the Bering Sea from 2011-08-07 to...

  20. Plankton and other data collected from net casts in the Gulf of Alaska and Bering Sea from the NOAA Ship MILLER FREEMAN from 26 April 1976 to 31 May 1976 (NODC Accession 7700419)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Plankton and other data were collected using net casts in the Gulf of Alaska and Bering Sea from the NOAA Ship MILLER FREEMAN from 26 April 1976 to 31 May 1976....

  1. Acoustics short-term passive monitoring using sonobuoys in the Bering, Chukchi, and Western Beaufort Seas conducted by Alaska Fisheries Scientific Center, National Marine Mammal Laboratory from 2007-08-01 to 2015-09-28 (NCEI Accession 0138863)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has conducted passive acoustic monitoring in the Bering, Chukchi, and Western Beaufort Seas to determine...

  2. Marine Toxic Substance and other data from bottle casts in the Bering Sea from helicopter as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 16 September 1976 to 20 September 1976 (NODC Accession 7700783)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine Toxic Substance and other data were collected from bottle casts in the Bering Sea from a helicopter. Data were collected by Pacific Marine Environmental...

  3. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea from helicopters as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 19 May 1976 to 29 May 1976 (NODC Accession 7700018)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Bering Sea from helicopters. Data were collected by the University...

  4. Herring spawning and other data from aircraft from the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 07 May 1977 to 28 October 1978 (NODC Accession 8100538)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Herring spawning and other data were collected from aircraft from the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP)....

  5. Drifting buoy and other data from drifting platforms in the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 17 January 1981 to 20 June 1981 (NODC Accession 8200120)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifting buoy data was collected from drifting platforms in the Bering Sea by the Flow Research Company as part of the Outer Continental Shelf Environmental...

  6. Zooplankton, physical, and other data collected by CHELAN in Bering Sea using CTD, bottle, net, and tide gauge casts from 18 July 1934 to 25 August 1934 (NODC Accession 9500110)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton, physical, and other data were collected using CTD, bottle, net, and tide gauge casts from CHELAN in the Bering Sea. Data were collected from 18 July...

  7. Marine toxic substance and other data from grab casts in the Bering Sea from the USCGC POLAR STAR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 29 April 1980 to 28 June 1980 (NODC Accession 8100551)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine toxic substance and other data were collected from grab casts in the Bering Sea from the USCGC POLAR STAR from 29 April 1980 to 28 June 1980. Data were...

  8. Marine toxic substance and other data from bottle casts in the Bering Sea from NOAA Ship DISCOVERER as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1981-05-11 to 1981-06-04 (NODC Accession 8200099)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine toxic substance and other data were collected from bottle casts in the Bering Sea from NOAA Ship DISCOVERER from 11 May 1981 to 04 June 1981. Data were...

  9. l680bs.m77t - MGD77 data file for Geophysical data from field activity L-6-80-BS in North Bering Sea, Alaska from 07/08/1980 to 07/28/1980

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-6-80-BS in North Bering Sea, Alaska...

  10. l475bs.m77t - MGD77 data file for Geophysical data from field activity L-4-75-BS in Bering Sea, Aleutian Basin, Alaska from 09/07/1975 to 09/18/1975

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-4-75-BS in Bering Sea, Aleutian Basin,...

  11. Cetacean line-transect survey conducted in the eastern Bering Sea shelf by Alaska Fisheries Science Center, National Marine Mammal Laboratory from NOAA Ship Miller Freeman from 1999-07-07 to 2004-06-30 (NCEI Accession 0131862)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visual surveys for cetaceans were conducted on the eastern Bering Sea shelf along transect lines, in association with the AFSC’s echo integration trawl surveys...

  12. Temperature profile data from XBT casts in the Bering Sea and other locations from the Voluntary Observing Ship Program (VOSP) from 01 January 1989 to 02 July 1990 (NODC Accession 9000191)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile data were collected from XBT casts in the Bering Sea and other locations by the Voluntary Observing Ship Program (VOSP). Data were collected by...

  13. Biological, chemical and other data collected aboard the THOMAS G. THOMPSON during cruise TN250 in the Bering Sea from 2010-06-16 to 2010-07-15 (NODC Accession 0117398)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0117398 includes biological, chemical, optical and physical data collected aboard the THOMAS G. THOMPSON during cruise TN250 in the Bering Sea from...

  14. Killer whale surveys conducted in the Aleutian Islands, Bering Sea, and western and central Gulf of Alaska by Alaska Fisheries Science Center, National Marine Mammal Laboratory from 2001-07-01 to 2010-07-12 (NCEI Accession 0137766)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a compilation of line-transect data collected on surveys in the Aleutian Islands, Bering Sea, and western and central Gulf of Alaska, 2001 - 2010....

  15. Moored current meter data collected from the Bering Sea in support of the Fisheries Oceanography Cooperative Investigations (FOCI) project from 12 September 1995 to 16 September 1996 (NODC Accession 0000674)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Moored current meter data were collected from the Bering Sea from September 12, 1995 to September 16, 1996. Data were collected by the Pacific Marine Environmental...

  16. Marine mammal specimen and other data from the Bering Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 18 November 1976 to 23 November 1976 (NODC Accession 7800800)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected from the Bering Sea and other locations from 18 November 1976 to 23 November 1976. Data were collected by the...

  17. l483bs.m77t - MGD77 data file for Geophysical data from field activity L-4-83-BS in Bering Sea, Alaska from 09/16/1983 to 10/02/1983

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-4-83-BS in Bering Sea, Alaska from...

  18. l776bs.m77t - MGD77 data file for Geophysical data from field activity L-7-76-BS in Bering Sea, Alaska from 09/03/1976 to 09/10/1976

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, gravity, and magnetic data along with DGPS navigation data was collected as part of field activity L-7-76-BS in Bering Sea, Alaska from...

  19. l980bs.m77t - MGD77 data file for Geophysical data from field activity L-9-80-BS in Bering Sea, Alaska from 09/24/1980 to 10/06/1980

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry, magnetics, and gravity data along with transit satellite navigation data was collected as part of field activity L-9-80-BS in Bering Sea,...

  20. Pliocene diatom and sponge spicule oxygen isotope ratios from the Bering Sea: isotopic offsets and future directions

    Directory of Open Access Journals (Sweden)

    A. M. Snelling

    2014-05-01

    Full Text Available Oxygen isotope analyses of different size fractions of Pliocene diatoms (δ18Odiatom from the Bering Sea show no evidence of an isotope offset and support the use of bulk diatom species samples for palaeoceanographic reconstructions. Additional samples containing concentrations of sponge spicules produce δ18O values several per mille lower than δ18Odiatom with a calculated mean offset of 3.6‰ ± 0.7. This difference is significantly greater than modern day variations in water δ18O through the regional water column. Despite the potential for oxygen isotope disequilibrium within δ18Osponge, there appears to be some similarity between δ18Osponge and a global stacked benthic δ18Oforam record. This highlights the potential for δ18Osponge in palaeoenvironmental research at sites where carbonates are not readily preserved.

  1. Cetacean distribution and abundance in relation to oceanographic domains on the eastern Bering Sea shelf: 1999-2004

    Science.gov (United States)

    Friday, Nancy A.; Waite, Janice M.; Zerbini, Alexandre N.; Moore, Sue E.

    2012-06-01

    Visual line transect surveys for cetaceans were conducted on the eastern Bering Sea shelf in association with pollock stock assessment surveys aboard the NOAA ship Miller Freeman in June and July of 1999, 2000, 2002, and 2004. Transect survey effort ranged from 1188 km in 1999 to 3761 km in 2002. Fin whales (Balaenoptera physalus) were the most common large whale in all years except 2004 when humpback whales (Megaptera novaeangliae) were more abundant. Dall's porpoise (Phocoenoides dalli) were the most common small cetacean in all years. Abundance estimates were calculated by year for each oceanographic domain: coastal, middle, and outer/slope. The middle and outer/slope domains were divided into two strata ("north" and "south") because of variable survey effort. The distribution and abundance of baleen whales changed between the earlier (colder) and later (warmer) survey years. Fin whales consistently occupied the outer shelf and secondarily the middle shelf, and their abundance was an order of magnitude greater in cold compared to warm years. Humpback whales "lived on the margin" of the northern Alaska Peninsula, eastern Aleutian Islands and Bristol Bay; their preferred habitat is possibly associated with areas of high prey availability due to nutrient upwelling and aggregation mechanisms. Minke whales (Balaenoptera acutorostrata) occur shoreward of fin whales in the outer and middle shelf and in coastal habitats along the Alaska Peninsula. The highest abundance for this species was observed in a cold (1999) year. No clear relationship emerged for odontocetes with regard to warm and cold years. Dall's porpoise occupied both outer and middle domains and harbor porpoise (Phocoena phocoena) were more common in middle and coastal domains. This study provided a unique, broad-scale assessment of cetacean distribution and abundance on the eastern Bering Sea shelf and a baseline for future comparisons.

  2. CO2 cycling in the coastal ocean. I - A numerical analysis of the southeastern Bering Sea with applications to the Chukchi Sea and the northern Gulf of Mexico

    Science.gov (United States)

    Walsh, John J.; Dieterle, Dwight A.

    A quasi-two dimensional model of the carbon and nitrogen cycling above the 70m isobath of the southeastern Bering Sea at 57°N replicates the observed seasonal cycles of nitrate, ammonium, ΣCO2, pCO2, light penetration, chlorophyll, phytoplankton growth rate, and primary production, as constrained by changes in wind, incident radiation, temperature, ice cover, vertical and lateral mixing, grazing stress, benthic processing of phytodetritus and zooplankton fecal pellets, and the pelagic microbial loop of DOC, bacteria, and their predators. About half of the seasonal resupply of nitrate stocks to their initial winter conditions is derived from in situ nitrification, with the rest obtained from deep-sea influxes. Under the present conditions of atmospheric forcing, shelf-break exchange, and food web structure, this shelf ecosystem serves as a sink for atmospheric CO2, with storage in the forms of exported DOC, DIC, and unutilized POC (phytoplankton, bacteria, and fecal pellets). As a consequence of just the rising levels of atmospheric pCO2 since the the Industrial Revolution, however, the biophysical CO2 status of the Southeastern Bering Sea shelf may have switched over the last 250 years, from a prior source to the present sink, since this relatively pristine ecosystem has unergone little eutrophication. Such fluctuations of CO2 status may thus be reversed by the physical processes of : (1) reduction of atmospheric pCO2, (2) increased on welling of deep-sea ΣCO2, and (3) warming of shelf waters. Based on our application of this model to the Chukchi Sea and the Gulf of Mexico, about 1.0-1.2 gigatons C y-1 of atmospheric CO2 may now be sequestered by temperate and polar shelf ecosystems. When tropical systems are included, however, a positive net sink of only 0.6-0.8. × 1015g C y-1 may prevail over all shelves.

  3. Paleoceanographic records and sea ice extension history on the slope of the northern Bering Sea over the last 100 ka B.P.

    Institute of Scientific and Technical Information of China (English)

    WANG Rujian; LI Xia; XIAO Wenshen; XIA Peifen; CHEN Ronghua

    2005-01-01

    Quantitative analytic results of the biogenic components in Core B2-9 from the northern Bering Sea slope indicate that the coarse fraction and opal content, serving as proxies of surface productivity, have increased stepwise since the marine isotope stage(MIS)5.3, reflecting periodic enhancement in surface productivity. The surface productivity attained its highest level during the Holocene, followed by MIS 3.2 to 2 and then MIS 5.3 to 3.3 with a lowest level. High total organic carbon(TOC) contents, together with high C/N ratios,which stand mostly between 7 and 20, show that the TOC was deposited from mixing sources. Therefore,one has to be cautious to use TOC as a proxy of surface productivity. The high TOC and C/N ratio during MIS 5.1, 3.3 to 3.2 and the Holocene reflect that the terrigenous organic matter input increased during interglacial periods. Increases in the fine- and silt-grained terrigenous components from MIS 5.3 to the middle Holocene imply that with the cooling climate, sea ice on the Bering Sea slope extended continuously. Ice-rafted and charcoal detritus increased during glacial, interstadial and the last deglaciation periods and decreased during interglacial periods,suggesting that sea ice on the slope increased and melted, respectively, during glacial and interglacial periods. The extension of sea ice during glacial periods,which was linked with the climate over the North American Continent, responded to global climate change during late Quaternary glacial and interglacial cycles.

  4. Effects of seasonal and interannual variability in along-shelf and cross-shelf transport on groundfish recruitment in the eastern Bering Sea

    Science.gov (United States)

    Vestfals, Cathleen D.; Ciannelli, Lorenzo; Duffy-Anderson, Janet T.; Ladd, Carol

    2014-11-01

    The Bering Sea responds rapidly to atmospheric perturbations and over the past several decades has experienced extreme variability in both its physical and biological characteristics. These changes can impact organisms that inhabit the region, particularly marine fishes, as normal current patterns to which reproductive habits are tuned can be disrupted, which, in turn, may influence recruitment and population dynamics. To understand the influence of ocean circulation on groundfish recruitment in the eastern Bering Sea, we examined transport along and across the Bering Slope derived from 23 years (1982-2004) of simulations from a Regional Ocean Modeling System (ROMS) ocean circulation model. We expected that changes in the strength and position of the Bering Slope Current (BSC) would affect recruitment in selected species (Pacific cod, walleye pollock, Greenland halibut, Pacific halibut, and arrowtooth flounder), and that circulation features along and across the shelf edge would be strongly influenced by atmospheric forcing. Variability in along-shelf transport at three transects along the path of the BSC, cross-shelf transport across the 100 and 200 m isobaths, and transport through Unimak Pass were examined. Strong seasonal and interannual variations in flow were observed, with transport typically highest during fall and winter months, coinciding with timing of spawning activity in the five species. Significant correlations were found between transport, BSC position, and groundfish recruitment. Pacific cod, in particular, benefitted from decreased along-shelf and on-shelf flow, while Pacific halibut recruitment increased in relation to increased on-shelf transport through southern canyons. The results of this study improve our understanding of variability in circulation and associated effects on groundfish recruitment in the eastern Bering Sea.

  5. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea from the SEA SOUNDER as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 08 July 1977 to 29 July 1977 (NODC Accession 7700848)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Bering Sea from the SEA SOUNDER. Data were collected by the...

  6. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Beaufort Sea and Bering Sea from 2006-08-21 to 2006-09-29 (NODC Accession 0112268)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112268 includes biological, chemical, discrete sample, physical and profile data collected from MIRAI in the Beaufort Sea and Bering Sea from...

  7. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the Pyxis in the Bering Sea, Caribbean Sea and others from 2001-11-06 to 2013-04-25 (NODC Accession 0081041)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0081041 includes chemical, meteorological, physical and underway - surface data collected from Pyxis in the Bering Sea, Caribbean Sea, Coastal Waters...

  8. A Photographic Catalog of Killer Whales, Orcinus orca, frOIll the Central Gulf of Alaska to the Southeastern Bering Sea

    OpenAIRE

    Dahlheim, Marilyn E

    1997-01-01

    In 1992 and 1993, researchers from the National Marine Mammal Laboratory initiated photo-identification studies on Alaskan killer whales, Orcinus orca. Waters from Kodiak Island west to the central and eastern Aleutian Islands and southeastern Bering Sea were surveyed. A total of 289 individual whales were identified. A photographic record of the whales encountered during these surveys is presented. When photographs of the 289 individual whales were compared among various regions in Alaska...

  9. Late Pliocene to early Pleistocene (2.4-1.25 Ma) paleoproductivity changes in the Bering Sea: IODP expedition 323 Hole U1343E

    Science.gov (United States)

    Kim, Sunghan; Khim, Boo-Keun; Takahashi, Kozo

    2016-03-01

    Late Pliocene to early Pleistocene paleoproductivity changes in the Bering Sea were reconstructed using geochemical concentrations and mass accumulation rates (MARs) of CaCO3, biogenic opal, and total organic carbon (TOC), and sedimentary nitrogen isotope ratios (δ15N) at IODP Expedition 323 Hole U1343E, drilled in the northern slope area (1956 m deep) of the Bering Sea. CaCO3 concentration is generally low, but prominent CaCO3 peaks occur intermittently due to subseafloor authigenic carbonate formation rather than biogenic accumulation, regardless of glacial-interglacial variations. Biogenic opal concentrations reflect orbital-scale glacial-interglacial variations. However, TOC concentration did not show clear glacial-interglacial variation, probably due to poor preservation. The sedimentary δ15N values vary synchronously with biogenic opal concentration on orbital timescales. The co-varying pattern of opal productivity and δ15N values at Hole U1343E is a result of nutrient utilization controlled by diatom productivity in the Bering slope area where Fe is not a limiting factor. Biogenic opal and TOC MARs showed a temporal shift at around 1.9 Ma from a high productivity period under nutrient-enriched conditions to a low productivity period under relatively nutrient-depleted conditions. High diatom productivity with low δ15N values before 1.9 Ma is associated with abundant nutrient supply by upwelling in relation to strong surface current system. This productivity decrease at about 1.9 Ma was also found in the southern Bering Sea (Site U1341) and may be related to global opal reorganization.

  10. AFSC/ABL: Genetic analysis of juvenile chum salmon from the Chukchi Sea and Bering Strait

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Arctic region has experienced warming in recent years, resulting in decreased summer sea ice cover and increased sea surface temperatures. In 2007, the U.S....

  11. Structure-forming corals and sponges and their use as fish habitat in Bering Sea submarine canyons.

    Directory of Open Access Journals (Sweden)

    Robert J Miller

    Full Text Available Continental margins are dynamic, heterogeneous settings that can include canyons, seamounts, and banks. Two of the largest canyons in the world, Zhemchug and Pribilof, cut into the edge of the continental shelf in the southeastern Bering Sea. Here currents and upwelling interact to produce a highly productive area, termed the Green Belt, that supports an abundance of fishes and squids as well as birds and marine mammals. We show that in some areas the floor of these canyons harbors high densities of gorgonian and pennatulacean corals and sponges, likely due to enhanced surface productivity, benthic currents and seafloor topography. Rockfishes, including the commercially important Pacific ocean perch, Sebastes alutus, were associated with corals and sponges as well as with isolated boulders. Sculpins, poachers and pleuronectid flounders were also associated with corals in Pribilof Canyon, where corals were most abundant. Fishes likely use corals and sponges as sources of vertical relief, which may harbor prey as well as provide shelter from predators. Boulders may be equivalent habitat in this regard, but are sparse in the canyons, strongly suggesting that biogenic structure is important fish habitat. Evidence of disturbance to the benthos from fishing activities was observed in these remote canyons. Bottom trawling and other benthic fishing gear has been shown to damage corals and sponges that may be very slow to recover from such disturbance. Regulation of these destructive practices is key to conservation of benthic habitats in these canyons and the ecosystem services they provide.

  12. Body Size Regression Formulae, Proximate Composition and Energy Density of Eastern Bering Sea Mesopelagic Fish and Squid.

    Science.gov (United States)

    Sinclair, Elizabeth H; Walker, William A; Thomason, James R

    2015-01-01

    The ecological significance of fish and squid of the mesopelagic zone (200 m-1000 m) is evident by their pervasiveness in the diets of a broad spectrum of upper pelagic predators including other fishes and squids, seabirds and marine mammals. As diel vertical migrators, mesopelagic micronekton are recognized as an important trophic link between the deep scattering layer and upper surface waters, yet fundamental aspects of the life history and energetic contribution to the food web for most are undescribed. Here, we present newly derived regression equations for 32 species of mesopelagic fish and squid based on the relationship between body size and the size of hard parts typically used to identify prey species in predator diet studies. We describe the proximate composition and energy density of 31 species collected in the eastern Bering Sea during May 1999 and 2000. Energy values are categorized by body size as a proxy for relative age and can be cross-referenced with the derived regression equations. Data are tabularized to facilitate direct application to predator diet studies and food web models.

  13. Body Size Regression Formulae, Proximate Composition and Energy Density of Eastern Bering Sea Mesopelagic Fish and Squid.

    Directory of Open Access Journals (Sweden)

    Elizabeth H Sinclair

    Full Text Available The ecological significance of fish and squid of the mesopelagic zone (200 m-1000 m is evident by their pervasiveness in the diets of a broad spectrum of upper pelagic predators including other fishes and squids, seabirds and marine mammals. As diel vertical migrators, mesopelagic micronekton are recognized as an important trophic link between the deep scattering layer and upper surface waters, yet fundamental aspects of the life history and energetic contribution to the food web for most are undescribed. Here, we present newly derived regression equations for 32 species of mesopelagic fish and squid based on the relationship between body size and the size of hard parts typically used to identify prey species in predator diet studies. We describe the proximate composition and energy density of 31 species collected in the eastern Bering Sea during May 1999 and 2000. Energy values are categorized by body size as a proxy for relative age and can be cross-referenced with the derived regression equations. Data are tabularized to facilitate direct application to predator diet studies and food web models.

  14. Structure-forming corals and sponges and their use as fish habitat in Bering Sea submarine canyons.

    Science.gov (United States)

    Miller, Robert J; Hocevar, John; Stone, Robert P; Fedorov, Dmitry V

    2012-01-01

    Continental margins are dynamic, heterogeneous settings that can include canyons, seamounts, and banks. Two of the largest canyons in the world, Zhemchug and Pribilof, cut into the edge of the continental shelf in the southeastern Bering Sea. Here currents and upwelling interact to produce a highly productive area, termed the Green Belt, that supports an abundance of fishes and squids as well as birds and marine mammals. We show that in some areas the floor of these canyons harbors high densities of gorgonian and pennatulacean corals and sponges, likely due to enhanced surface productivity, benthic currents and seafloor topography. Rockfishes, including the commercially important Pacific ocean perch, Sebastes alutus, were associated with corals and sponges as well as with isolated boulders. Sculpins, poachers and pleuronectid flounders were also associated with corals in Pribilof Canyon, where corals were most abundant. Fishes likely use corals and sponges as sources of vertical relief, which may harbor prey as well as provide shelter from predators. Boulders may be equivalent habitat in this regard, but are sparse in the canyons, strongly suggesting that biogenic structure is important fish habitat. Evidence of disturbance to the benthos from fishing activities was observed in these remote canyons. Bottom trawling and other benthic fishing gear has been shown to damage corals and sponges that may be very slow to recover from such disturbance. Regulation of these destructive practices is key to conservation of benthic habitats in these canyons and the ecosystem services they provide. PMID:22470486

  15. The Structure of Genetic Diversity in Eelgrass (Zostera marina L.) along the North Pacific and Bering Sea Coasts of Alaska

    Science.gov (United States)

    Talbot, Sandra L.; Sage, George K; Rearick, Jolene R.; Fowler, Meg C.; Muñiz-Salazar, Raquel; Baibak, Bethany; Wyllie-Echeverria, Sandy; Cabello-Pasini, Alejandro; Ward, David H.

    2016-01-01

    Eelgrass (Zostera marina) populations occupying coastal waters of Alaska are separated by a peninsula and island archipelago into two Large Marine Ecosystems (LMEs). From populations in both LMEs, we characterize genetic diversity, population structure, and polarity in gene flow using nuclear microsatellite fragment and chloroplast and nuclear sequence data. An inverse relationship between genetic diversity and latitude was observed (heterozygosity: R2 = 0.738, P < 0.001; allelic richness: R2 = 0.327, P = 0.047), as was significant genetic partitioning across most sampling sites (θ = 0.302, P < 0.0001). Variance in allele frequency was significantly partitioned by region only in cases when a population geographically in the Gulf of Alaska LME (Kinzarof Lagoon) was instead included with populations in the Eastern Bering Sea LME (θp = 0.128–0.172; P < 0.003), suggesting gene flow between the two LMEs in this region. Gene flow among locales was rarely symmetrical, with notable exceptions generally following net coastal ocean current direction. Genetic data failed to support recent proposals that multiple Zostera species (i.e. Z. japonica and Z. angustifolia) are codistributed with Z. marina in Alaska. Comparative analyses also failed to support the hypothesis that eelgrass populations in the North Atlantic derived from eelgrass retained in northeastern Pacific Last Glacial Maximum refugia. These data suggest northeastern Pacific populations are derived from populations expanding northward from temperate populations following climate amelioration at the terminus of the last Pleistocene glaciation. PMID:27104836

  16. Paleoproductivity and paleoceanography of the last 4.3 Myrs at IODP Expedition 323 Site U1341 in the Bering Sea based on biogenic opal content

    Science.gov (United States)

    Iwasaki, Shinya; Takahashi, Kozo; Kanematsu, Yoshiyuki; Asahi, Hirofumi; Onodera, Jonaotaro; Ravelo, A. C.

    2016-03-01

    Site U1341 in the southern Bering Sea was drilled and cored down to 600 meters below sea-floor (mbsf) during Integrated Ocean Drilling Program (IODP) Expedition 323, covering a nearly complete record of the last 4.3 million years (Myrs). Analyses of the biogenic opal content of sediments at the site provide detailed and useful information on past biological productivity and paleoceanographic changes that occurred in the region including shifts in the oceanographic condition during the intensification of the Northern Hemisphere Glaciation (NHG) and the Mid-Pleistocene Transition (MPT). An overall decreasing trend in the %biogenic opal record, combined with evidence from microfossil assemblages, indicates a gradual shift in environmental conditions during the last 4.3 Myrs, from warm and nutrient-rich conditions to cool conditions with sea-ice. On the other hand, biogenic opal mass accumulation rates (MAR) were high during 2.6-2.1 Ma after the intensification of the NHG, unlike in the western North Pacific. High biological productivity during this specific interval is consistent with the results of previous studies in the other Marginal Seas, possibly suggesting that iron leakage from the Bering Continental Shelf occurred. After the MPT, the data suggest that there was sea-ice expansion and discharge of lithogenic matter during glacial periods, and high productivity during interglacial periods.

  17. Foraging Responses of Black-Legged Kittiwakes to Prolonged Food-Shortages around Colonies on the Bering Sea Shelf

    Science.gov (United States)

    Paredes, Rosana; Orben, Rachael A.; Suryan, Robert M.; Irons, David B.; Roby, Daniel D.; Harding, Ann M. A.; Young, Rebecca C.; Benoit-Bird, Kelly; Ladd, Carol; Renner, Heather; Heppell, Scott; Phillips, Richard A.; Kitaysky, Alexander

    2014-01-01

    We hypothesized that changes in southeastern Bering Sea foraging conditions for black-legged kittiwakes (Rissa tridactyla) have caused shifts in habitat use with direct implications for population trends. To test this, we compared at-sea distribution, breeding performance, and nutritional stress of kittiwakes in three years (2008–2010) at two sites in the Pribilof Islands, where the population has either declined (St. Paul) or remained stable (St. George). Foraging conditions were assessed from changes in (1) bird diets, (2) the biomass and distribution of juvenile pollock (Theragra chalcogramma) in 2008 and 2009, and (3) eddy kinetic energy (EKE; considered to be a proxy for oceanic prey availability). In years when biomass of juvenile pollock was low and patchily distributed in shelf regions, kittiwake diets included little or no neritic prey and a much higher occurrence of oceanic prey (e.g. myctophids). Birds from both islands foraged on the nearby shelves, or made substantially longer-distance trips overnight to the basin. Here, feeding was more nocturnal and crepuscular than on the shelf, and often occurred near anticyclonic, or inside cyclonic eddies. As expected from colony location, birds from St. Paul used neritic waters more frequently, whereas birds from St. George typically foraged in oceanic waters. Despite these distinctive foraging patterns, there were no significant differences between colonies in chick feeding rates or fledging success. High EKE in 2010 coincided with a 63% increase in use of the basin by birds from St. Paul compared with 2008 when EKE was low. Nonetheless, adult nutritional stress, which was relatively high across years at both colonies, peaked in birds from St. Paul in 2010. Diminishing food resources in nearby shelf habitats may have contributed to kittiwake population declines at St Paul, possibly driven by increased adult mortality or breeding desertion due to high foraging effort and nutritional stress. PMID:24671108

  18. Differences in nitrous oxide distribution patterns between the Bering Sea basin and Indian Sector of the Southern Ocean

    Institute of Scientific and Technical Information of China (English)

    CHEN Liqi; ZHANG Jiexia; ZHAN Liyang; LI Yuhong; SUN Heng

    2014-01-01

    Nitrous oxide (N2O) distribution patterns in the Bering Sea basin (BSB) and Indian Sector of the Southern Ocean (ISSO) were described and compared. In both sites, the waters were divided into four layers:surface layer, subsurface layer, N2O maximum layer, and deep water. Simulations were made to find out the most important factors that regulate the N2O distribution patterns in different layers of both sites. The results showed that in the surface water, N2O was more understaturated in the ISSO than the BSB. This phenom-enon in the surface water of ISSO may result from ice melt water intrusion and northeastward transport of the Antarctic surface water. Results of the rough estimation of air-sea fluxes during the expedition were (-0.34±0.07)-(-0.64±0.13) μmol/(m2·d) and (-1.47±0.42)-(-1.77±0.51) μmol/(m2·d) for the BSB and the ISSO, respectively. Strongly stratified surface layer and temperature minimum layer restricted exchange across the thermocline. The N2O maximum existed in higher concentration and deeper in the BSB than the ISSO, but their contribution to the upper layer by eddy diffusions was negligible. In deep waters, a concen-tration difference of 5 nmol/L N2O between these two sites was found, which suggested that N2O produc-tion occurred during thermohaline circulation. N2O may be a useful tracer to study important large-scale hydrographic processes.

  19. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the XUE LONG in the Arctic Ocean, Beaufort Sea and Bering Sea from 2008-07-30 to 2008-09-11 (NODC Accession 0109932)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0109932 includes chemical, meteorological, physical and underway - surface data collected from XUE LONG in the Arctic Ocean, Beaufort Sea and Bering...

  20. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2002-05-05 to 2002-06-15 (NODC Accession 0113952)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113952 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  1. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2004-07-18 to 2004-08-26 (NODC Accession 0115707)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115707 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  2. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2002-07-18 to 2002-08-21 (NODC Accession 0113953)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113953 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  3. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2004-05-15 to 2004-06-23 (NODC Accession 0115592)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115592 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  4. Bioaccumulation of HCHs and DDTs in organs of Pacific salmon (genus Oncorhynchus) from the Sea of Okhotsk and the Bering Sea.

    Science.gov (United States)

    Lukyanova, Olga N; Tsygankov, Vasiliy Yu; Boyarova, Margarita D; Khristoforova, Nadezhda K

    2016-08-01

    Concentrations of isomers of hexachlorocyclohexane (α-, β-, γ-HCH) and dichlorodiphenyltrichloroethane (DDT) and its metabolites (dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE) were assessed in organs of the pink (Oncorhynchus gorbuscha), chum (Oncorhynchus keta), chinook (Oncorhynchus tshawytscha), and sockeye salmon (Oncorhynchus nerka), caught near the Kuril Islands (the northern-western part of the Pacific Ocean), in the Sea of Okhotsk and the Bering Sea. Pesticides have been found to accumulate in fish organs in the following: muscles < liver < eggs < male gonads. The highest concentrations in muscles and liver have been recorded from sockeye. Of the DDT group, only DDE has been detected. The average concentration of HCHs + DDE in the muscles of pink, chum, chinook, and sockeye was 141, 125, 1241, 1641 ng/g lipids, respectively; and in the liver, 279, 183, 1305, 3805 ng/g lipids, respectively. The total concentration of HCHs isomers was higher than that of DDE. Average HCHs + DDE concentration in organs of salmon from study area is lower than that in salmon from Pacific coast of North America. PMID:27219293

  5. Evidence of prolonged aragonite undersaturations in the bottom waters of the southern Bering Sea shelf from autonomous sensors

    Science.gov (United States)

    Mathis, Jeremy T.; Cross, Jessica N.; Monacci, Natalie; Feely, Richard A.; Stabeno, Phyllis

    2014-11-01

    The southeastern shelf of the Bering Sea is a dynamic area that experiences seasonal variability in primary production and remineralization of organic matter, both of which control the carbon biogeochemistry of the water column. Surface-water partial pressure of carbon dioxide (pCO2) is greatly reduced in summer by biological production, which increases carbonate mineral saturation states (Ω). In contrast, the export of large quantities of organic matter from surface blooms drives an active remineralization loop that sharply increases pCO2 near the bottom, lowering pH and suppressing Ω. New observations from moored biogeochemical sensors in 2011 showed that seasonal net community production lowers surface-water pCO2, causing large gradients between the ocean and atmosphere that are sustained throughout the summer, confirming that these waters likely remain supersaturated with respect to aragonite throughout the open water season. On the other hand, moored sensors deployed near the bottom showed that pCO2 levels exceed 500 μatm by early June and remain at these high levels well into the autumn months, indicating that the bottom waters are likely continuously undersaturated in aragonite for at least several months during each year. Only a small fraction of the increased pCO2 can currently be attributed to the intrusion of anthropogenic CO2 from the atmosphere, while the majority is due to natural respiration processes. The biological impacts, along with the timing and duration of these undersaturation events, could play a role in the development of larval and juvenile calcifiers in the region and will change as anthropogenic CO2 concentrations continue to rise.

  6. Cycladophora davisiana (Radiolarian) in the Bering Sea during the late Quaternary: A stratigraphic tool and proxy of the glacial Subarctic Pacific Intermediate Water

    Institute of Scientific and Technical Information of China (English)

    WANG Rujian; CHEN Ronghua

    2005-01-01

    Cycladophora davisiana (Radiolarian) contents are counted in two cores of the Bering Sea and correlated well with the oxygen isotopic records of ice in the deep core obtained by the Greenland Ice Sheet Project II (GISP 2) and deep-sea sediments (SPECMAP) of the world oceans. Millennial scale climatic events, for example, Younge Dryas and B(φ)lling/Aller(φ)d events, Heinrich1 and Dansgaard-Oeschger1events, recorded by C. davisiana percents are distinguished from Core B4-2. C. davisiana events b, c1, c2, d, e1 and e2, respectively, corresponding to oxygen isotopic 2.0, 3.1, 3.3, 4.0, 5.1 and 5.3, are identified from Core B2-9. High resolution records of C. davisian are tuned to the oxygen isotopic records in GISP 2 and SPECMAP and the depth-age frameworks are established in the two cores, supplying a stratigraphic base for future paleoceanographic and paleoclimatic studies. High C. davisiana during the glacial periods in the two cores indicate that they can serve as a proxy of the glacial Subarctic Pacific Intermediate Water, which verifies the glacial Subarctic Pacific Intermediate Water brought from the Bering Sea.

  7. Differential responses of seabirds to environmental variability over 2 years in the continental shelf and oceanic habitats of southeastern Bering Sea

    Science.gov (United States)

    Yamamoto, Takashi; Kokubun, Nobuo; Kikuchi, Dale M.; Sato, Nobuhiko; Takahashi, Akinori; Will, Alexis P.; Kitaysky, Alexander S.; Watanuki, Yutaka

    2016-04-01

    Seasonal sea-ice cover has been decreasing in the southeastern Bering Sea shelf, which might affect ecosystem dynamics and availability of food resources to marine top predators breeding in the region. In this study, we investigated the foraging responses of two seabird species, surface-foraging red-legged kittiwakes Rissa brevirostris (hereafter, RLKI) and pursuit-diving foraging thick-billed murres Uria lomvia (TBMU) to different marine environmental conditions over 2 years. At-sea distributions of RLKI and TBMU breeding on St. George Island, the largest seabird colony in the region, were recorded using GPS loggers, and blood samples were taken to examine their physiological condition and isotopic foraging niche in a given year. Between the study years, winter ice retreated earlier and summer water temperatures were relatively warmer in 2014 compared to those in 2013. RLKI foraging occurred mostly over the oceanic basin in both years. TBMU, however, foraged mostly over the shelf but showed a relatively higher use of the shelf break and oceanic basin in 2013. The foraging distances from the colony peaked at 250-300 km in 2013 and bimodally at 150-250 and 300-350 km in 2014 for RLKI and tended to be farther in 2013 compared to those in 2014 for TBMU. Plasma levels of corticosterone did not differ between the years in RLKI but differed in TBMU, showing higher levels of physiological stress incurred by murres in 2013, the year of relatively cooler sea surface temperatures with later sea-ice retreat. δ13N (a proxy of trophic level of prey) did not differ between the years in either RLKI or TBMU. These results suggest that the response of ecosystem dynamics to climate variability in the southeastern Bering Sea may differ between the ocean basin and continental shelf regions, which, in turn, may generate differential responses in seabirds relying on those habitats for foraging.

  8. The size-fractionated chlorophyll a and primary productivity in the Bering Sea during the summer of 2003

    Institute of Scientific and Technical Information of China (English)

    LIU Zilin; CHEN Jianfang; CHEN Zhongyuan; ZHANG Tao; ZHANG Haisheng

    2005-01-01

    Investigations of chlorophyll a and primary productivity were carried out in the Bering Sea along the BR line and the BS line during the Second Chinese National Arctic Research Expedition in the summer of 2003. The results showed that the surface chlorophyll a concentrations were 0.199~1.170 μg/dm3, and the average value was 0.723 μg/dm3 on the BR line. For the BS line, the surface chlorophyll a concentrations were 0.519~4.644 μg/dm3 (average 1.605 μg/dm3) and 0.568~14.968 μg/dm3 (average 5.311 μg/dm3)during the early and late summer, respectively. The average value in the late summer was much higher than that in the early summer.The high values (more than 4.0 μg/dm3) occurred at stations of the BS line in the southern Bering Strait. The chlorophyll a concentrations in the subsurface layer were higher than those in the surface layer. The results of the size-fractionated chlorophyll a showed that the contribution of the picoplankton to total chlorophyll a was the predominance at the early summer and the contribution of the netplankton was the predominance at the late summer. The carbon potential primary productivities varied between 0.471 and 1.147 mg/(m3·h) on the BR line, with average rates of 0.728 mg/(m3·h). The primary productivities on the BS line were much higher than those of the BR line, ranging from 1.227 mg/(m3·h) at the early summer to 19.046 mg/(m3·h) at the late summer. The results of 1.147 mg/(m3·h) on the BR line, with average rates of 0.728 mg/(m3·h). The primary productivities on the BS line were much higher than those of the BR line, ranging from 1.227 mg/(m3·h) at the early summer to 19.046 mg/(m3·h) at the late summer. The results of the size-fractionated primary productivity showed that the contribution of the nanoplankton to total productivity was the predominance at the early summer and the contribution of the netplankton was predominance at the late summer. The assimilation number of photosynthesis was 0.45~2.80 mg

  9. 40Ar-39Ar dating and tectonic implications of volcanic rocks recovered at IODP Hole U1342A and D on Bowers Ridge, Bering Sea

    Science.gov (United States)

    Sato, Keiko; Kawabata, Hiroshi; Scholl, David W.; Hyodo, Hironobu; Takahashi, Kozo; Suzuki, Katsuhiko; Kumagai, Hidenori

    2016-03-01

    During the Integrated Ocean Drilling Program (IODP), a total of 41.54 m of basement rock, consolidated volcaniclastic sediment, was recovered beneath a thin sediment cover. The drilled site is at the eastern end of the crestal area of Bowers Ridge, a north and westward sweeping offshoot of the Aleutian Arc into the Bering Sea. The volcanic sequence recovered from Holes U1342A and U1342D was divided into six major lithologic units. We used the single grain 40Ar-39Ar dating method performed by step-wise heated laser fusion technique to date andesites of Unit 1. Thereby two ages of Oligocene volcanism (34-32 Ma, 28-26 Ma) were distinguished each other according to our 40Ar-39Ar data. These ages refute a hypothesized Cretaceous origin in the North Pacific as an exotic arc massif or sector of the Hawaiian-Emperor chain and indicate that the Bowers Ridge is a Bering-Sea formed arc or remnant arc that ceased forming in the latest Oligocene to the earliest Miocene time.

  10. Phytoplankton composition and its ecological effect in subsurface cold pool of the northern Bering Sea in summer as revealed by HPLC derived pigment signatures

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Yanpei; JIN Haiyan; LI Hongliang; CHEN Jianfang; WANG Bin; CHEN Fajin; BAI Youcheng; LU Yong; TIAN Shichao

    2014-01-01

    CHEMTAX analysis of high-performance liquid chromatography (HPLC) pigment was conducted to study phytoplankton community structure in the northern Bering Sea shelf, where a seasonal subsurface cold pool emerges. The results showed that fucoxanthin (Fuco) and chlorophyll a (Chl a) were the most abundant diagnostic pigments, with the integrated water column values ranging from 141 to 2 160 µg/m2 and 477 to 5 535 µg/m2, respectively. Moreover, a diatom bloom was identified at Sta. BB06 with the standing stock of Fuco up to 9 214 µg/m3. The results of CHEMTAX suggested that the phytoplankton community in the northern Bering Sea shelf was dominated by diatoms and chrysophytes with an average relative contribu-tion to Chl a of 80%and 12%, respectively, followed by chlorophytes, dinoflagellates, and cryptophytes. Dia-toms were the absolutely dominant algae in the subsurface cold pool with a relative contribution exceeding 90%, while the contribution of chrysophytes was generally higher in oligotrophic upper water. Additionally, the presence of a cold pool would tend to favor accumulation of diatom biomass and a bloom that occurred beneath the halocline would be beneficial to organic matter sinks, which suggests that a large part of the phytoplankton biomass would settle to the seabed and support a rich benthic biomass.

  11. Feeding habits of Dall's porpoises ( Phocoenoides dalli) in the subarctic North Pacific and the Bering Sea basin and the impact of predation on mesopelagic micronekton

    Science.gov (United States)

    Ohizumi, Hiroshi; Kuramochi, Toshiaki; Kubodera, Tsunemi; Yoshioka, Motoi; Miyazaki, Nobuyuki

    2003-05-01

    We investigated the stomach contents of Dall's porpoises collected in pelagic waters spanning most of their range in the North Pacific and the Bering Sea. Analysis revealed the porpoises fed mainly on myctophid fishes in the subarctic North Pacific and on gonatid squids as well as myctophid fishes in the Bering Sea. Most of the prey items were mesopelagic micronekton, primarily fishes and squids that migrate vertically to shallower waters at night. Stomach content was greater during twilight hours, suggesting the porpoises foraged actively on myctophids at night in shallower waters. Stomach contents were strongly characterized by local mesopelagic prey fauna, and prey species selectivity was not apparent. The annual consumption by Dall's porpoises was estimated to be 2.0-2.8 million tons, or 4.7-6.5% of the biomass of mesopelagic fishes in the subarctic North Pacific, and may account for approximately 24-33% of the overall mortality of mesopelagic micronekton, especially myctophids. Myctophids are also common, but less important, prey of other subarctic predators. Dall's porpoises are likely the primary consumers of myctophids in the subarctic North Pacific. Since myctophids are the major component of the mesotrophic level, the trophic relationship between myctophids and Dall's porpoises is thought to be an important pathway of mass and energy in the pelagic food web in the subarctic North Pacific.

  12. l578bs.m77t - MGD77 data file for Geophysical data from field activity L-5-78-BS in Bering Sea, Alaska from 08/05/1978 to 08/09/1978

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry and gravity data along with DGPS navigation data was collected as part of field activity L-5-78-BS in Bering Sea, Alaska from 08/05/1978 to...

  13. l780bs.m77t - MGD77 data file for Geophysical data from field activity L-7-80-BS in Bering Sea, Alaska from 08/01/1980 to 08/26/1980

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Single-beam bathymetry and gravity data along with DGPS navigation data was collected as part of field activity L-7-80-BS in Bering Sea, Alaska from 08/01/1980 to...

  14. 78 FR 42970 - Notice of Intent To Prepare a Resource Management Plan for the Bering Sea-Western Interior...

    Science.gov (United States)

    2013-07-18

    ... existing 1981 Southwest Planning Area Management Framework Plan and portions of the 1986 Central Yukon RMP..., Evaluation, Planning, and Management; 15. The BLM will incorporate Environmental Justice considerations in... Bureau of Land Management Notice of Intent To Prepare a Resource Management Plan for the Bering...

  15. Seismic Velocity and Thickness of Sediments Beneath the Aleutian Basin, Bering Sea

    Science.gov (United States)

    Scheirer, D. S.; Barth, G. A.; Sliter, R. W.; Hart, P. E.; Childs, J. R.

    2014-12-01

    The thickness and seismic velocity structure of sediments of the Aleutian Basin were mapped during a 2011 multichannel seismic (MCS) cruise of the R/V Langseth. Combined with legacy MCS, sonobuoy, and scientific drilling data, the Langseth observations allowed us to study the history of sedimentation in this area. Semblance velocity analyses from common-depth-point gathers of the 8-km-long streamer data were conducted at-sea every 6.25 km. Post-cruise, these semblance analyses were refined and supplemented with new analyses where significant basement topography is present. The flat-lying nature of both the seafloor and the within-sediment reflectors allowed determination of interval velocity and thickness values with high precision using the Dix equation. Two prominent bottom-simulating reflections (BSRs) are common within the sediment column: a shallower one inferred to represent the base of gas hydrate stability, and a deeper one inferred to represent the diagenetic transformation from opal-A to opal-CT. This latter transition was reached by the one deep hole (Site 190, DSDP Leg19) drilled into the Aleutian Basin, where the lithologic contrast prevented further penetration. The gas hydrate BSR is associated with subvertical velocity-amplitude anomalies, and the opal A/CT transition is associated with a large decrease in reflector amplitudes beneath it, indicating the decrease in acoustic impedance contrasts associated with diagenetic dewatering. Seismic interval velocities range from 1600 m/sec at the top of the sediment column to 2800-3500 m/sec at its base. The largest step in interval velocity occurs at the opal A/CT transition. Interval velocities are laterally continuous over many tens of kilometers, and this continuity allows the generation of seismic travel-time vs. sediment thickness relationships across the basin. A second-degree polynomial relationship between time and thickness, developed by regression of all of the semblance velocity analyses from the

  16. Relevance of a Particularly Sensitive Sea Area to the Bering Strait Region: a Policy Analysis Using Resilience-Based Governance Principles

    Directory of Open Access Journals (Sweden)

    Kevin Hillmer-Pegram

    2015-03-01

    Full Text Available The Bering Strait, separating the North American and Asian continents, is a productive social-ecological marine system that is vulnerable to increasing maritime traffic. In other parts of the world, the International Maritime Organization (IMO, an agency of the United Nations, has designated similar marine systems as a Particularly Sensitive Sea Area (PSSA in an effort to protect vulnerable resources from international shipping. We present information about the 14 existing PSSAs around the world and the political process by which designation is achieved. We examine specific characteristics of the Bering Strait system that are relevant to a PSSA application; these include vulnerable resources such as marine mammals and their contribution to the food and cultural security of indigenous communities, threats to these resources from shipping activities, and the viable mitigation options to reduce these threats. We then use five criteria derived from empirical research on resilience-based governance to analyze whether a PSSA designation would promote the resilience of marine mammal populations and indigenous communities to increased maritime activities. Despite the elusiveness of a definitive answer, we conclude that although the designation is not a perfect fit from a theoretical standpoint, it still holds the potential to benefit marine mammals and indigenous communities in terms of resilience. We conclude by identifying critical challenges and trade-offs that practitioners would need to negotiate when attempting to apply theoretical governance principles via real-world policy tools.

  17. Planktonic foraminiferal biostratigraphy and assemblages in the Bering Sea during the Pliocene and Pleistocene: IODP sites U1340 and U1343

    Science.gov (United States)

    Husum, Katrine

    2016-03-01

    IODP Site U1340 and Site U1343 in the Bering Sea have been investigated with regard to planktonic foraminifers and fragmentation. The base of Site U1340 dates back to the Early Pliocene and the base of Site U1343 to the Early Pleistocene. Site U1340 is situated at Bowers Ridge, the southern Bering Sea. Site U1343 is situated near the gateway to the Arctic Ocean in the northern Bering Sea. At both sites there are none or very few planktonic foraminifers during the Pliocene and early Pleistocene. After 1.3-1.4 Ma the planktonic foraminifers are continuously present for most of the samples examined. Three stratigraphic events have been identified in this study. The first occurrence (FO) of Neogloboquadrina inglei is observed at 1.4-1.5 Ma, although this event may be affected by poor preservation of foraminifers in older sediments. The observed age of the change in the coiling ratio of Neogloboquadrina pachyderma from right to left at 1.2 Ma agrees with the dating of the same event at the Californian margin. The age of the last occurrence (LO) of N. inglei also seems to match the same event from the Californian margin at 0.7 Ma. This implies that these events are robust regional events for the entire northern Pacific. Multivariate analyses of the quantitative planktonic foraminifer data show three main faunal assemblages. The oldest assemblage from 1.3-1.4 Ma to 1.2 Ma is dominated by N pachyderma s.l. (dex) together with Globigerina bulloides. Other species in this fauna are N. inglei, N. pachyderma s.l. (sin), Globigerina umbilicata and Turborotalita quinqueloba. After 1.2 Ma the faunal assemblage is dominated by N. pachyderma s.l. (sin), but the remaining species are the same as before. At 0.7 Ma N. inglei disappears, whilst the remaining fauna assemblage stays the same, with N. pachyderma s.l. (sin) still dominating, reflecting subpolar-polar conditions. Prior to 1.4-1.3 Ma there are very few or no planktonic foraminifers. Low shell fragmentation and lower TOC

  18. Absorption and fluorescence properties of chromophoric dissolved organic matter of the eastern Bering Sea in the summer with special reference to the influence of a cold pool

    Science.gov (United States)

    D'Sa, E. J.; Goes, J. I.; Gomes, H.; Mouw, C.

    2014-06-01

    The absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) are reported for the inner shelf, slope waters and outer shelf regions of the eastern Bering Sea during the summer of 2008, when a warm, thermally stratified surface mixed layer lay over a cold pool (factor analysis (PARAFAC) revealed large variability in the characteristics of CDOM in different regions of the Bering Sea. PARAFAC analysis aided in the identification of three humic-like (components one, two and five) and two protein-like (a tyrosine-like component three, and a tryptophan-like component four) components. In the extensive shelf region, average absorption coefficients at 355 nm (ag355, m-1) and DOC concentrations (μM) were highest in the inner shelf (0.342 ± 0.11 m-1, 92.67 ± 14.60 μM) and lower in the middle (0.226 ± 0.05 m-1, 78.38 ± 10.64 μM) and outer (0.185 ± 0.05 m-1, 79.24 ± 18.01 μM) shelves, respectively. DOC concentrations, however were not significantly different, suggesting CDOM sources and sinks to be uncoupled from DOC. Mean spectral slopes S were elevated in the middle shelf (24.38 ± 2.25 μm-1) especially in the surface waters (26.87 ± 2.39 μm-1) indicating high rates of photodegradation in the highly stratified surface mixed layer, which intensified northwards in the northern middle shelf likely contributing to greater light penetration and to phytoplankton blooms at deeper depths. The fluorescent humic-like components one, two, and five were most elevated in the inner shelf most likely from riverine inputs. Along the productive "green belt" in the outer shelf/slope region, absorption and fluorescence properties indicated the presence of fresh and degraded autochthonous DOM. Near the Unimak Pass region of the Aleutian Islands, low DOC and ag355 (mean 66.99 ± 7.94 μM; 0.182 ± 0.05 m-1) and a high S (mean 25.95 ± 1.58 μm-1) suggested substantial photobleaching of the Alaska Coastal Water, but high intensities of humic-like and

  19. Oceanographic profile data collected from sound velocimeter - moving vessel profiler casts aboard FAIRWEATHER as part of project M-R908-FA-06 in the Bering Sea and North Pacific Ocean from 2006-07-31 to 2006-08-20 (NCEI Accession 0130285)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0130285 includes physical and profile data collected aboard the FAIRWEATHER during project M-R908-FA-06 in the Bering Sea and North Pacific Ocean...

  20. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHN V. VICKERS in the Bering Sea, North Pacific Ocean and South Pacific Ocean from 1992-08-16 to 1992-10-21 (NODC Accession 0115003)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115003 includes chemical, discrete sample, physical and profile data collected from JOHN V. VICKERS in the Bering Sea, North Pacific Ocean and South...

  1. Marine animal sighting, benthic organism, and other data from aircraft and other platforms in the Bering and Beaufort Seas as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 19 August 1971 to 12 March 1983 (NODC Accession 8500273)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine animal sighting, benthic organism, and other data were collected from aircraft and other platforms in the Bering and Beaufort Seas from 19 August 1971 to 12...

  2. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea from the MOANA WAVE as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 30 June 1976 to 09 August 1976 (NODC Accession 7601709)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Bering Sea from the MOANA WAVE. Data were collected by the Pacific...

  3. Temperature profile data from surface sensors, bottle casts, and CTD casts from the Bering Sea from the R/V ALPHA HELIX as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 21 April 1988 to 20 May 1988 (NODC Accession 8800172)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile data were collected from surface sensors, bottle casts, and CTD casts in the Bering Sea from the R/V ALPHA HELIX from 21 April 1988 to 20 May...

  4. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea from the ACONA and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 21 September 1976 to 02 October 1976 (NODC Accession 7601928)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Bering Sea from the ACONA and other platforms. Data were collected...

  5. Marine mammal specimen and other data from NOAA Ship DISCOVERER and other platforms in the Bering Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1975-10-27 to 1977-07-12 (NODC Accession 7700220)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected from NOAA Ship DISCOVERER and other platforms in the Bering Sea and other locations from 27 October 1975 to 12...

  6. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Barometric pressure sensor, Carbon dioxide (CO2) gas analyzer and other instruments from OSCAR DYSON in the Bering Sea, Gulf of Alaska and North Pacific Ocean from 2014-03-03 to 2014-08-13 (NCEI Accession 0144980)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144980 includes Surface underway data collected from OSCAR DYSON in the Bering Sea, Gulf of Alaska and North Pacific Ocean from 2014-03-03 to...

  7. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Bering Sea and North Pacific Ocean from 2001-08-28 to 2001-09-14 (NODC Accession 0112257)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112257 includes chemical, discrete sample, physical and profile data collected from MIRAI in the Bering Sea and North Pacific Ocean from 2001-08-28...

  8. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from Surface underway, discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from MIRAI in the Bering Sea, North Pacific Ocean and South Pacific Ocean from 2007-10-08 to 2007-12-26 (NODC Accession 0108123)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108123 includes Surface underway, discrete sample and profile data collected from MIRAI in the Bering Sea, North Pacific Ocean and South Pacific...

  9. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Bering Sea and North Pacific Ocean from 2008-10-11 to 2008-11-07 (NODC Accession 0112271)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112271 includes chemical, discrete sample, physical and profile data collected from MIRAI in the Bering Sea and North Pacific Ocean from 2008-10-11...

  10. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Bering Sea and North Pacific Ocean from 2002-10-11 to 2002-11-06 (NODC Accession 0112258)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112258 includes chemical, discrete sample, physical and profile data collected from MIRAI in the Bering Sea and North Pacific Ocean from 2002-10-11...

  11. Physical and other data from bottle and CTD casts in the Bering Sea from NOAA Ship OCEANOGRAPHER as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1974-12-31 to 1975-02-13 (NODC Accession 7601551)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical and other data were collected from bottle and CTD casts in the Bering Sea from NOAA Ship OCEANOGRAPHER. Data were collected by the University of Alaska -...

  12. Marine bird sighting and other data from NOAA Ship DISCOVERER and other platforms from the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1975-08-20 to 1977-08-04 (NODC Accession 7900090)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from NOAA Ship DISCOVERER and other platforms in the Bering Sea from 20 August 1975 to 04 August 1977. Data were...

  13. Benthic organism and other data from otter trawls from NOAA Ship MILLER FREEMAN from the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1976-04-01 to 1976-06-01 (NODC Accession 7700850)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic organism and other data were collected from otter trawls in the Bering Sea from NOAA Ship MILLER FREEMAN by University of Alaska; Institute of Marine...

  14. Fish survey, fishing duration, and other data from net trawls in the Bering Sea from the MILLER FREEMAN and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 01 April 1976 to 09 August 1976 (NODC Accession 7700847)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls in the Bering Sea from the MILLER FREEMAN and other platforms from 01 April 1976 to 09...

  15. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HEALY in the Bering Sea from 2008-03-29 to 2008-05-06 (NCEI Accession 0144549)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144549 includes discrete sample and profile data collected from HEALY in the Bering Sea from 2008-03-29 to 2008-05-06. These data include AMMONIUM...

  16. Physical, meteorological, and other data from surface sensors, bottle casts, and CTD casts in the Bering Sea from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 17 April 1977 to 01 May 1977 (NODC Accession 7800310)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors, bottle casts, and CTD casts in the Bering Sea from the SURVEYOR. Data were collected...

  17. Marine animal sighting and census data from aircraft and other platforms from the Southeastern Bering Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 07 March 1979 to 04 March 1983 (NODC Accession 8600251)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine animal sighting and census data were collected from aircraft and other platforms in the Bering Sea and other locations from 07 March 1979 to 044 March 1983....

  18. Marine Toxic Substance and other data from bottle casts in the Bering Sea and other locations from the MOANA WAVE as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 June 1976 to 08 July 1976 (NODC Accession 7700782)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine Toxic Substance and other data were collected from bottle casts in the Bering Sea and North Pacific Ocean from the MOANA WAVE. Data were collected by Pacific...

  19. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea and other locations from the DISCOVERER as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 12 August 1975 to 15 October 1975 (NODC Accession 7700422)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Bering Sea and other locations from the DISCOVERER. Data were...

  20. Physical, meteorological, and other data from surface sensors, bottle casts, and CTD casts in the Bering Sea from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 18 March 1977 to 04 April 1977 (NODC Accession 7800309)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors, bottle casts, and CTD casts in the Bering Sea from the SURVEYOR. Data were collected...

  1. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the THOMAS G. THOMPSON in the Bering Sea, North Pacific Ocean and South Pacific Ocean from 1993-07-05 to 1993-09-02 (NODC Accession 0115008)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115008 includes chemical, discrete sample, physical and profile data collected from THOMAS G. THOMPSON in the Bering Sea, North Pacific Ocean and...

  2. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from HEALY in the Bering Sea from 2008-07-03 to 2008-07-31 (NCEI Accession 0144981)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144981 includes discrete sample and profile data collected from HEALY in the Bering Sea from 2008-07-03 to 2008-07-31. These data include AMMONIUM...

  3. Fish survey, fishing duration, and other data from net trawls in the Bering Sea from NOAA Ship MILLER FREEMAN and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1975-08-07 to 1975-10-21 (NODC Accession 7601681)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls in the Bering Sea from NOAA Ship MILLER FREEMAN and other platforms from 07 August 1975...

  4. Fish survey, fishing duration, and other data from net trawls in the Bering Sea and other locations from the G. B. REED and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 21 September 1948 to 19 February 1976 (NODC Accession 7601767)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish survey, fishing duration, and other data were collected from net trawls in the Bering Sea and other locations from the G. B. REED and other platforms from 21...

  5. Modeling connectivity of walleye pollock in the Gulf of Alaska: Are there any linkages to the Bering Sea and Aleutian Islands?

    Science.gov (United States)

    Parada, Carolina; Hinckley, Sarah; Horne, John; Mazur, Michael; Hermann, Albert; Curchister, Enrique

    2016-10-01

    We investigated the connectivity of walleye pollock in the Gulf of Alaska (GOA) and linkages to the Bering Sea (BS) and Aleutian Island (AL) regions. We used a spatially-explicit Individual-based model (IBM) coupled to 6 years of a hydrodynamic model that simulates the early life history of walleye pollock in the GOA (eggs to age-0 juveniles). The processes modeled included growth, movement, mortality, feeding and the bioenergetics component for larvae and juveniles. Simulations were set to release particles on the 1st of the month (February to May) in fourteen historical spawning areas in the GOA up to the 1st of September each year. Model results reproduced the link between the Shelikof Strait spawning area and the Shumagin nursery region for March and April spawners, besides other Potential Nursery Areas (PNAs) found in the GOA. A prominent finding of this study was the appearance of the BS as important PNAs for several GOA spawning grounds, which is supported by a consistent flow into the BS through Unimak Pass. The simulations showed the highest density of simulated surviving pollock in the western Bering Sea (WBS) region with the lowest coefficients of variation of the whole domain. Three spawning sectors were defined, which aggregate multiple spawning areas in the eastern (EGOA), central (CGOA) and western Gulf of Alaska (WGOA). A connectivity matrix showed strong retention within the CGOA (25.9%) and EGOA (23.8%), but not in the WGOA (7.2%). Within the GOA, the highest connectivity is observed from EGOA to CGOA (57.8%) followed by the connection from CGOA to WGOA (24.3%). Overall, one of the most prominent connections was from WGOA to WBS (62.8%), followed by a connection from CGOA to WBS (29.2%). In addition, scenarios of shifting spawning locations and nursery sectors of GOA, BS and AL are explored and implications for walleye pollock stock structure hypotheses are discussed.

  6. A cross-shelf gradient in δ15N stable isotope values of krill and pollock indicates seabird foraging patterns in the Bering Sea

    Science.gov (United States)

    Jones, Nathan M.; Hoover, Brian A.; Heppell, Scott A.; Kuletz, Kathy J.

    2014-11-01

    Concurrent measurements of predator and prey δ15N isotope values demonstrated that a cross-shelf isotopic gradient can propagate through a marine food web from forage species to top-tier predators and indicate foraging areas at a scale of tens of kilometers. We measured δ13C and δ15N in muscle tissues of thick-billed murres (Uria lomvia) and black-legged kittiwakes (Rissa tridactyla), and in whole body tissues of walleye pollock (Gadus chalcogrammus) and krill (Thysanoessa spp), sampled across the continental shelf break in the Bering Sea in 2008 and in 2009. We found significant basin-shelf differences at fine scales (trophic signal and spatial structure of a basin-shelf δ15Nitrogen gradient in the central and southern Bering Sea, and used it to contrast foraging patterns of thick-billed murres and kittiwakes on the open ocean. Seabird muscle δ15N values were compared to baselines created from measurements in krill and pollock tissues sampled concurrently throughout the study area. Krill, pollock, and murre tissues from northern, shallow, shelf habitat (200 m) to the south and west. Krill δ15N baseline values predicted 35-42% of the variability in murre tissue values. Patterns between kittiwakes and prey were less coherent. The persistence of strong spatial autocorrelation among sample values, and a congruence of geospatial patterns in δ15N among murre and prey tissues, suggest that murres forage repeatedly in specific areas. Murre isotope values showed distinct geospatial stratification, coincident with the spatial distribution of three colonies: St. Paul, St. George, and Bogoslof. This suggests some degree of foraging habitat partitioning among colonies.

  7. Differential responses of seabirds to inter-annual environmental change in the continental shelf and oceanic habitats of southeastern Bering Sea

    Directory of Open Access Journals (Sweden)

    T. Yamamoto

    2015-11-01

    Full Text Available Seasonal sea-ice cover has been decreasing in the southeastern Bering Sea shelf, which might affect ecosystem dynamics and availability of food resources to marine top predators breeding in the region. In this study, we investigated the foraging responses of two seabird species, surface-foraging red-legged kittiwakes Rissa brevirostris (hereafter, RLKI and pursuit-diving foraging thick-billed murres Uria lomvia (TBMU to the inter-annual change in environmental conditions. Between the study years, winter ice retreated earlier and summer water temperatures were warmer in 2014 compared to those in 2013. At-sea distributions of RLKI and TBMU breeding on St. George Island, the largest seabird colony in the region, were recorded using GPS loggers, and blood samples were taken to examine their physiological condition and isotopic foraging niche in a given year. RLKI foraging occurred mostly over the oceanic basin in both years. TBMU, however, foraged mostly over the shelf, but showed a relatively higher use of the shelf break and oceanic basin in the colder year, 2013. The foraging distances from the colony peaked at 250–300 km in 2013 and, bimodally, at 150–250 and 300–350 km in 2014 for RLKI, and tended to be farther in 2013 compared to those in 2014 for TBMU. Plasma levels of corticosterone did not differ between years in RLKI, but differed in TBMU, showing higher levels of physiological stress incurred by murres during the colder year, 2013. δ13N (a proxy of trophic level of prey did not differ between the years in either RLKI or TBMU, while δ13C (a proxy of prey origin were lower in 2014 than in 2013 in both species, suggesting possible differences in influx of oceanic prey items into foraging areas. These results suggest that the response of ecosystem dynamics to climate variability in the southeast Bering Sea may differ between the ocean basin and continental shelf regions, which, in turn, may generate differential responses in seabirds

  8. Absorption and fluorescence properties of the eastern Bering Sea in the summer with special reference to the influence of a Cold Pool

    Science.gov (United States)

    D'Sa, E. J.; Goes, J. I.; Gomes, H.; Mouw, C.

    2013-12-01

    The absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) are reported for the inner shelf, slope waters and outer shelf regions of the eastern Bering Sea during the summer of 2008, when a warm, thermally stratified surface mixed layer lay over a Cold Pool (factor analysis (PARAFAC) revealed large variability in the characteristics of CDOM in different regions of the Bering Sea. PARAFAC analysis aided in the identification of three humic-like (components 1, 2 and 5) and two protein-like (a tyrosine-like component 3, and a tryptophan-like component 4) components. In the extensive shelf region, average absorption coefficients at 355 nm (ag355 m-1) and DOC concentrations (μM) were highest in the inner shelf (0.342 ± 0.11 m-1, 92.67 ± 14.60 μM) and lower in the middle (0.226 ± 0.05 m-1, 78.38 ± 10.64 μM) and outer (0.176 ± 0.05 m-1, 80.73 ± 18.11 μM) shelves, respectively. Mean spectral slopes S were elevated in the middle shelf (24.38 ± 2.25 μm-1) especially in the surface waters (26.87 ± 2.39 μm-1) indicating high rates of photodegradation in the highly stratified surface mixed layer, which intensified northwards in the northern middle shelf likely contributing to greater light penetration and to phytoplankton blooms at deeper depths. The fluorescent humic-like components 1, 2, and 5 were most elevated in the inner shelf most likely from riverine inputs. Measurements at depth in slope waters (> 250 m) revealed low values of ag355 (0.155 ± 0.03 m-1) and S (15.45 ± 1.78 μm-1) indicative of microbial degradation of CDOM in deep waters. DOC concentrations, however were not significantly different suggesting CDOM sources and sinks to be uncoupled from DOC. Along the productive "green belt" in the outer shelf/slope region, absorption and fluorescence properties indicated the presence of fresh and degraded autochthonous DOM. Near the Unimak Pass region of the Aleutian Islands, low DOC and ag355 (mean 66.99 ± 7.94 μM; 0

  9. Sediment classification using neural networks: An example from the site-U1344A of IODP Expedition 323 in the Bering Sea

    Science.gov (United States)

    Ojha, Maheswar; Maiti, Saumen

    2016-03-01

    A novel approach based on the concept of Bayesian neural network (BNN) has been implemented for classifying sediment boundaries using downhole log data obtained during Integrated Ocean Drilling Program (IODP) Expedition 323 in the Bering Sea slope region. The Bayesian framework in conjunction with Markov Chain Monte Carlo (MCMC)/hybrid Monte Carlo (HMC) learning paradigm has been applied to constrain the lithology boundaries using density, density porosity, gamma ray, sonic P-wave velocity and electrical resistivity at the Hole U1344A. We have demonstrated the effectiveness of our supervised classification methodology by comparing our findings with a conventional neural network and a Bayesian neural network optimized by scaled conjugate gradient method (SCG), and tested the robustness of the algorithm in the presence of red noise in the data. The Bayesian results based on the HMC algorithm (BNN.HMC) resolve detailed finer structures at certain depths in addition to main lithology such as silty clay, diatom clayey silt and sandy silt. Our method also recovers the lithology information from a depth ranging between 615 and 655 m Wireline log Matched depth below Sea Floor of no core recovery zone. Our analyses demonstrate that the BNN based approach renders robust means for the classification of complex lithology successions at the Hole U1344A, which could be very useful for other studies and understanding the oceanic crustal inhomogeneity and structural discontinuities.

  10. 77 FR 22750 - Fisheries of the Exclusive Economic Zone Off Alaska; Groundfish Fisheries in the Bering Sea and...

    Science.gov (United States)

    2012-04-17

    ... FR 77535, December 13, 2010, corrected 75 FR 81921, December 29, 2010). The 2011 Steller sea lion... the population status and foraging behavior of Steller sea lions--in the Aleutian Islands subarea. The... Alaska to prepare an EIS on the Steller sea lion protection measures implemented in January 2011 (75...

  11. Ship-borne Observations of Atmospheric Black Carbon Aerosol Particles over the Arctic Ocean, Bering Sea, and North Pacific Ocean during September 2014

    Science.gov (United States)

    Taketani, F.; Miyakawa, T.; Takashima, H.; Komazaki, Y.; Kanaya, Y.; PAN, X.; Inoue, J.

    2015-12-01

    Measurements of refractory black carbon (rBC) aerosol particles using a highly sensitive online single particle soot photometer were performed on-board the R/V Mirai during a cruise across the Arctic Ocean, Bering Sea, and the North Pacific Ocean (31 August-9 October 2014). The measured rBC mass concentrations over the Arctic Ocean in the latitudinal region > 70°N were in the range 0-66 ng/m3 for 1-min averages, with an overall mean value of 1.0 ± 1.2 ng/m3. Single-particle-based observations enabled the measurement of such low rBC mass concentrations. The effects of long-range transport from continents to the Arctic Ocean were limited during the observed period, suggesting that such low rBC concentration levels would prevail over the Arctic Ocean. An analysis of rBC mixing states showed that particles with a non-shell/core structure made a significant contribution to the rBC particles detected over the Arctic Ocean.

  12. Bathymetry of the Bering Strait: Chukotka to Diomede Island

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The bathymetric map of the northern Bering Sea region, plate 1 of USGS Professional Paper 759-B, 1976, was generated using published National Ocean Service maps and...

  13. Change in coccolith size and morphology due to response to temperature and salinity in coccolithophore Emiliania huxleyi (Haptophyta) isolated from the Bering and Chukchi seas

    Science.gov (United States)

    Saruwatari, Kazuko; Satoh, Manami; Harada, Naomi; Suzuki, Iwane; Shiraiwa, Yoshihiro

    2016-05-01

    Strains of the coccolithophore Emiliania huxleyi (Haptophyta) collected from the subarctic North Pacific and Arctic oceans in 2010 were established as clone cultures and have been maintained in the laboratory at 15 °C and 32 ‰ salinity. To study the physiological responses of coccolith formation to changes in temperature and salinity, growth experiments and morphometric investigations were performed on two strains, namely MR57N isolated from the northern Bering Sea and MR70N at the Chukchi Sea. This is the first report of a detailed morphometric and morphological investigation of Arctic Ocean coccolithophore strains. The specific growth rates at the logarithmic growth phases in both strains markedly increased as temperature was elevated from 5 to 20 °C, although coccolith productivity (estimated as the percentage of calcified cells) was similar at 10-20 % at all temperatures. On the other hand, the specific growth rate of MR70N was affected less by changes in salinity in the range 26-35 ‰, but the proportion of calcified cells decreased at high and low salinities. According to scanning electron microscopy (SEM) observations, coccolith morphotypes can be categorized into Type B/C on the basis of their biometrical parameters. The central area elements of coccoliths varied from thin lath type to well-calcified lath type when temperature was increased or salinity was decreased, and coccolith size decreased simultaneously. Coccolithophore cell size also decreased with increasing temperature, although the variation in cell size was slightly greater at the lower salinity level. This indicates that subarctic and arctic coccolithophore strains can survive in a wide range of seawater temperatures and at lower salinities with change in their morphology. Because all coccolith biometric parameters followed the scaling law, the decrease in coccolith size was caused simply by the reduced calcification. Taken together, our results suggest that calcification productivity may

  14. Biophysical transport model suggests climate variability determines distribution of Walleye Pollock early life stages in the eastern Bering Sea through effects on spawning

    Science.gov (United States)

    Petrik, Colleen M.; Duffy-Anderson, Janet T.; Mueter, Franz; Hedstrom, Katherine; Curchitser, Enrique N.

    2015-11-01

    The eastern Bering Sea recently experienced an anomalously warm period followed by an anomalously cold period. These periods varied with respect to sea ice extent, water temperature, wind patterns, and ocean circulation. The distributions of Walleye Pollock early life stages also differed between periods, with larval stages found further eastward on the shelf in warm years. Statistical analyses indicated that these spatial distributions were more closely related to temperature than to other covariates, though a mechanism has not been identified. The objective of this study was to determine if variable transport could be driving the observed differences in pollock distributions. An individual-based model of pollock early life stages was developed by coupling a hydrodynamic model to a particle-tracking model with biology and behavior. Simulation experiments were performed with the model to investigate the effects of wind on transport, ice presence on time of spawning, and water temperature on location of spawning. This modeling approach benefited from the ability to individually test mechanisms to quantitatively assess the impact of each on the distribution of pollock. Neither interannual variability in advection nor advances or delays in spawning time could adequately represent the observed differences in distribution between warm and cold years. Changes to spawning areas, particularly spatial contractions of spawning areas in cold years, resulted in modeled distributions that were most similar to observations. The location of spawning pollock in reference to cross-shelf circulation patterns is important in determining the distribution of eggs and larvae, warranting further study on the relationship between spawning adults and the physical environment. The different distributions of pollock early life stages between warm and cold years may ultimately affect recruitment by influencing the spatial overlap of pollock juveniles with prey and predators.

  15. Does location really matter? An inter-colony comparison of seabirds breeding at varying distances from productive oceanographic features in the Bering Sea

    Science.gov (United States)

    Harding, Ann; Paredes, Rosana; Suryan, Robert; Roby, Daniel; Irons, David; Orben, Rachael; Renner, Heather; Young, Rebecca; Barger, Christopher; Dorresteijn, Ine; Kitaysky, Alexander

    2013-10-01

    Central place foragers, such as breeding seabirds, need to commute between their nests and foraging grounds, thus close proximity of the breeding colony to productive oceanographic features might be beneficial for seabird reproduction. We tested this hypothesis by investigating the at-sea foraging and breeding behavior of thick-billed murres (Uria lomvia) nesting at three colonies (Bogoslof, St. Paul, and St. George Islands) in the Bering Sea located at different distances from the productive continental shelf-break. We found that distances to feeding areas differed only during night trips among colonies. St. Paul murres foraged entirely on the shelf, whereas St. George murres commuted to the continental shelf-break at night and foraged on the shelf during the day. Bogoslof murres foraged in oceanic waters in close proximity to the colony. Murres breeding at the both Pribilof colonies spent less time attending nests and had higher levels of stress hormone corticosterone compared to murres breeding at Bogoslof, although chick-provisioning rates and fledging success were similar among the three colonies. Lower nest attendance and higher corticosterone suggest lower food availability in the Pribilof domain compared to the Bogoslof region. Murres breeding at the Pribilofs used different foraging strategies to buffer effects of food shortages on their reproduction: flight costs associated with longer distance night trips at St. George were presumably balanced by benefits of higher density and/or more lipid rich prey in the continental shelf-break regions, whereas the additional distance of St. Paul from the continental shelf-break may have outweighed any energetic gain. Murres exhibited a remarkable degree of plasticity of foraging strategies in response to changes in their food availability, but the breeding success of murres did not reflect either food limitations or the colony proximity to productive oceanographic features.

  16. NOAA marine environmental buoy data from the National Data Buoy Center in the Gulf of Alaska, Gulf of Mexico, Bering Sea, North Atlantic Ocean, North Pacific Ocean, Coastal Waters of SE Alaska, Coastal Waters of Western U.S., Great Lakes, North American Coastline-North, and North American Coastline-South from 2002-10-01 to 2002-10-31 (NODC Accession 0000400)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure, temperature, and other data were collected from fixed platforms in the Gulf of Alaska, Gulf of Mexico, Bering Sea, North Atlantic Ocean, North Pacific...

  17. Influence of timing of sea ice retreat on phytoplankton size during marginal ice zone bloom period in the Chukchi and Bering shelves

    Science.gov (United States)

    Fujiwara, A.; Hirawake, T.; Suzuki, K.; Eisner, L.; Imai, I.; Nishino, S.; Kikuchi, T.; Saitoh, S. I.

    2015-08-01

    Timing of sea ice retreat (TSR) as well as cell size of primary producers (i.e., phytoplankton) plays crucial roles in seasonally ice-covered marine ecosystem. Thus, it is important to monitor the temporal and spatial distribution of phytoplankton community size structure. Prior to this study, an ocean color algorithm has been developed to derive phytoplankton size index FL, which is defined as the ratio of chlorophyll a derived from the cells larger than 5 μm to the total chl a using satellite remote sensing for the Chukchi and Bering shelves. Using this method, we analyzed pixel-by-pixel relationships between FL during marginal ice zone (MIZ) bloom period and TSR over a period of 1998-2013. The influence of TSR on sea surface temperature (SST) and changes in ocean heat content (ΔOHC) during the MIZ bloom period were also investigated. A significant negative relationship between FL and TSR was widely found in the shelf region during MIZ bloom season. On the other hand, we found a significant positive (negative) relationship between SST (ΔOHC) and TSR. That is, earlier sea-ice retreat was associated with a dominance of larger phytoplankton during a colder and weakly stratified MIZ bloom season, suggesting that duration of nitrate supply, which is important for large-sized phytoplankton growth in this region (i.e., diatoms), can change according to TSR. In addition, under-ice phytoplankton blooms are likely to occur in years with late ice retreat, because sufficient light for phytoplankton growth can pass through the ice and penetrate into the water columns due to an increase in solar radiation toward the summer solstice. Moreover, we found not only the length of ice-free season but also annual median of FL positively correlated with annual net primary production (APP). Thus, both phytoplankton community composition and growing season are important for APP in the study area. Our findings showed quantitative relationship between the inter-annual variability of FL

  18. Influence of timing of sea ice retreat on phytoplankton size during marginal ice zone bloom period in the Chukchi and Bering shelves

    Directory of Open Access Journals (Sweden)

    A. Fujiwara

    2015-08-01

    Full Text Available Timing of sea ice retreat (TSR as well as cell size of primary producers (i.e., phytoplankton plays crucial roles in seasonally ice-covered marine ecosystem. Thus, it is important to monitor the temporal and spatial distribution of phytoplankton community size structure. Prior to this study, an ocean color algorithm has been developed to derive phytoplankton size index FL, which is defined as the ratio of chlorophyll a derived from the cells larger than 5 μm to the total chl a using satellite remote sensing for the Chukchi and Bering shelves. Using this method, we analyzed pixel-by-pixel relationships between FL during marginal ice zone (MIZ bloom period and TSR over a period of 1998–2013. The influence of TSR on sea surface temperature (SST and changes in ocean heat content (ΔOHC during the MIZ bloom period were also investigated. A significant negative relationship between FL and TSR was widely found in the shelf region during MIZ bloom season. On the other hand, we found a significant positive (negative relationship between SST (ΔOHC and TSR. That is, earlier sea-ice retreat was associated with a dominance of larger phytoplankton during a colder and weakly stratified MIZ bloom season, suggesting that duration of nitrate supply, which is important for large-sized phytoplankton growth in this region (i.e., diatoms, can change according to TSR. In addition, under-ice phytoplankton blooms are likely to occur in years with late ice retreat, because sufficient light for phytoplankton growth can pass through the ice and penetrate into the water columns due to an increase in solar radiation toward the summer solstice. Moreover, we found not only the length of ice-free season but also annual median of FL positively correlated with annual net primary production (APP. Thus, both phytoplankton community composition and growing season are important for APP in the study area. Our findings showed quantitative relationship between the inter

  19. Influence of timing of sea ice retreat on phytoplankton size during marginal ice zone bloom period on the Chukchi and Bering shelves

    Science.gov (United States)

    Fujiwara, A.; Hirawake, T.; Suzuki, K.; Eisner, L.; Imai, I.; Nishino, S.; Kikuchi, T.; Saitoh, S.-I.

    2016-01-01

    The size structure and biomass of a phytoplankton community during the spring bloom period can affect the energy use of higher-trophic-level organisms through the predator-prey body size relationships. The timing of the sea ice retreat (TSR) also plays a crucial role in the seasonally ice-covered marine ecosystem, because it is tightly coupled with the timing of the spring bloom. Thus, it is important to monitor the temporal and spatial distributions of a phytoplankton community size structure. Prior to this study, an ocean colour algorithm was developed to derive phytoplankton size index FL, which is defined as the ratio of chlorophyll a (chl a) derived from cells larger than 5 µm to the total chl a, using satellite remote sensing for the Chukchi and Bering shelves. Using this method, we analysed the pixel-by-pixel relationships between FL during the marginal ice zone (MIZ) bloom period and TSR over the period of 1998-2013. The influences of the TSR on the sea surface temperature (SST) and changes in ocean heat content (ΔOHC) during the MIZ bloom period were also investigated. A significant negative relationship between FL and the TSR was widely found in the shelf region during the MIZ bloom season. However, we found a significant positive (negative) relationship between the SST (ΔOHC) and TSR. Specifically, an earlier sea ice retreat was associated with the dominance of larger phytoplankton during a colder and weakly stratified MIZ bloom season, suggesting that the duration of the nitrate supply, which is important for the growth of large-sized phytoplankton in this region (i.e. diatoms), can change according to the TSR. In addition, under-ice phytoplankton blooms are likely to occur in years with late ice retreat, because sufficient light for phytoplankton growth can pass through the ice and penetrate into the water columns as a result of an increase in solar radiation toward the summer solstice. Moreover, we found that both the length of the ice-free season

  20. Zooplankton species composition, abundance and biomass on the eastern Bering Sea shelf during summer: The potential role of water-column stability and nutrients in structuring the zooplankton community

    Science.gov (United States)

    Coyle, Kenneth O.; Pinchuk, Alexei I.; Eisner, Lisa B.; Napp, Jeffrey M.

    2008-08-01

    The southeastern Bering Sea sustains one of the largest fisheries in the United States, as well as wildlife resources that support valuable tourist and subsistence economies. The fish and wildlife populations in turn are sustained by a food web linking primary producers to apex predators through the zooplankton community. Recent shifts in climate toward warmer conditions may threaten these resources by altering productivity and trophic relationships in the ecosystem on the southeastern Bering Sea shelf. We examined the zooplankton community near the Pribilof Islands and on the middle shelf of the southeastern Bering Sea in summer of 1999 and 2004 to document differences and similarities in species composition, abundance and biomass by region and year. Between August 1999 and August 2004, the summer zooplankton community of the middle shelf shifted from large to small species. Significant declines were observed in the biomass of large scyphozoans ( Chrysaora melanaster), large copepods ( Calanus marshallae), arrow worms ( Sagitta elegans) and euphausiids ( Thysanoessa raschii, T. inermis) between 1999 and 2004. In contrast, significantly higher densities of the small copepods ( Pseudocalanus spp., Oithona similis) and small hydromedusae ( Euphysa flammea) were observed in 2004 relative to 1999. Stomach analyses of young-of-the-year (age 0) pollock ( Theragra chalcogramma) from the middle shelf indicated a dietary shift from large to small copepods in 2004 relative to 1999. The shift in the zooplankton community was accompanied by a 3-fold increase in water-column stability in 2004 relative to 1999, primarily due to warmer water above the thermocline, with a mean temperature of 7.3 °C in 1999 and 12.6 °C in 2004. The elevated water-column stability and warmer conditions may have influenced the zooplankton composition by lowering summer primary production and selecting for species more tolerant of a warm, oligotrophic environment. A time series of temperature from

  1. Change in coccolith morphology by responding to temperature and salinity in coccolithophore Emiliania huxleyi (Haptophyta) isolated from the Bering and Chukchi Seas

    Science.gov (United States)

    Saruwatari, K.; Satoh, M.; Harada, N.; Suzuki, I.; Shiraiwa, Y.

    2015-11-01

    Strains of the coccolithophore Emiliania huxleyi (Haptophyta) collected from the subarctic North Pacific and Arctic Oceans during the R/V MIRAI cruise in 2010 (MR10-05) were established as clone cultures and have been maintained in the laboratory at 15 °C and 32 ‰ salinity. To study the physiological responses of coccolith formation to changes in temperature and salinity, growth experiments and morphometric investigations were performed on two strains of MR57N isolated from the northern Bering Sea (56°58' N, 167°11' W) and MR70N at the Chukchi Sea (69°99' N, 168° W). This is the first report of a detailed morphometric and morphological investigation of Arctic Ocean coccolithophore strains. The specific growth rates at the logarithmic growth phases in both strains markedly increased as temperature was elevated from 5 to 20 °C, although coccolith productivity (the percentage of calcified cells) was similar at 10-20 % at all temperatures. On the other hand, the specific growth rate of strain MR70N was affected less by changes in salinity in the range 26-35 ‰, but the proportion of calcified cells decreased at high and low salinities. According to scanning electron microscopy (SEM) observations, coccolith morphotypes can be categorized into Type B/C on the basis of their biometrical parameters, such as length of the distal shield (LDS), length of the inner central area (LICA), and the thickness of distal shield elements. The central area elements of coccoliths varied from grilled type to closed type when temperature was increased or salinity was decreased, and coccolith size decreased simultaneously. Coccolithophore cell size also decreased with increasing temperature, although the variation in cell size was slightly greater at the lower salinity level. This indicates that subarctic and arctic coccolithophore strains can survive in a wide range of seawater temperatures and at lower salinities due to their marked morphometric adaptation ability. Because all

  2. Foraging segregation of two congeneric diving seabird species (common and thick-billed murres breeding on St. George Island, Bering Sea

    Directory of Open Access Journals (Sweden)

    N. Kokubun

    2015-11-01

    Full Text Available Sub-arctic environmental changes are expected to affect the ecology of marine top predators. We examined the characteristics of foraging behavior of two sympatric congeneric diving seabirds, common (Uria aalge: hereafter COMU and thick-billed (U. lomvia: hereafter TBMU murres breeding on St. George Island located in the seasonal sea-ice region of the Bering Sea. We investigated their flight duration, diel patterns of dive depth, and underwater wing strokes, along with morphology and blood stable isotopes. Acceleration-temperature-depth data loggers were attached to chick-guarding birds, and behavioral data were obtained from 7 COMU and 12 TBMU. Both species showed similar trip duration (13.21 ± 4.79 h for COMU and 10.45 ± 7.09 h for TBMU and similar diurnal patterns of diving (frequent dives to various depths in the daytime and less frequent dives to shallow depths in the nighttime. During the daytime, dive depths of COMU had two peaks in shallow (18.1 ± 6.0 m and deep (74.2 ± 8.7 m depths, while those of TBMU were 20.2 ± 7.4 m and 59.7 ± 7.9 m. COMU showed more frequent wing strokes during the bottom phase of dives (1.90 ± 0.11 s−1 than TBMU (1.66 ± 0.15 s−1. Fishes occurred with higher proportion in the bill-loads brought back to chicks in COMU (85 % than in TBMU (56 %. δ15N value of blood was significantly higher in COMU (14.47 ± 0.27 ‰ than in TBMU (13.14 ± 0.36 ‰. Relatively small wing area (0.053 ± 0.007 m2 of COMU compared to TBMU (0.067 ± 0.007 m2 may make them more agile underwater and thus enable them to target more mobile prey including larger fishes that inhabit deeper depths. These differences in foraging behavior between COMU and TBMU might explain the differences in their responses to long-term marine environmental changes.

  3. Repeated occurrences of methanogenic zones, diagenetic dolomite formation and linked silicate alteration in southern Bering Sea sediments (Bowers Ridge, IODP Exp. 323 Site U1341)

    Science.gov (United States)

    Wehrmann, L. M.; Ockert, C.; Mix, A. C.; Gussone, N.; Teichert, B. M. A.; Meister, P.

    2016-03-01

    Diagenetic precipitates, such as dolomite, and the chemistry of residual deeply buried porewater often represent the only traces of past biogeochemical activity in marine sediments. A 600 m thick sedimentary section, recently drilled at Integrated Ocean Drilling Program (IODP) Site U1341 on Bowers Ridge (southern Bering Sea), provides insight into such a 4.3 Ma old paleo-diagenetic archive. Hard-lithified calcite-dolomite layers, and laminae of disseminated carbonate, were recovered in diatom-rich sediments over a depth range of 400 m. Carbon isotope values of the diagenetic carbonates between -16.6 and -14.4‰ (VPDB) and strontium isotope ratios of dolomites close to past seawater values suggest carbonate precipitation induced by the production of dissolved inorganic carbon (DIC) during elevated rates of organic carbon mineralization, primarily via sulfate reduction, at shallow sediment depth below the paleo-seafloor. Diagenetic carbonates at 280-440 m below seafloor were likely also produced by the intermittent onset of sulfate reduction coupled to the anaerobic oxidation of methane (AOM) at sulfate-methane transition zones (SMTZ). These microbially mediated processes do not occur in the sediment at this site at present but were likely connected to the presence of a methanogenic zone at 2.58-2.51 Ma. A minimum in sulfate concentrations in modern porewaters and low sedimentary Ba/Al ratios resulting from former sulfate depletion are reminiscent of the presence of this large methanogenic zone. The minimum in sulfate concentrations is reflected in a minimum in magnesium concentrations, less radiogenic strontium and isotopically light calcium in the porewater. It is proposed that magnesium was removed from the porewater during carbonate precipitation and volcanic ash alteration which occurred in the former methanogenic zone and also released strontium with a less radiogenic isotope ratio and isotopically light calcium into the porewater. The isotopic composition of

  4. Modern modes of provenance and dispersal of terrigenous sediments in the North Pacific and Bering Sea: implications and perspectives for palaeoenvironmental reconstructions

    Science.gov (United States)

    Wang, Rong; Biskaborn, Boris K.; Ramisch, Arne; Ren, Jian; Zhang, Yongzhan; Gersonde, Rainer; Diekmann, Bernhard

    2016-08-01

    During expedition 202 aboard the RV Sonne in 2009, 39 seafloor surface sediment sites were sampled over a wide sector of the North Pacific and adjoining Bering Sea. The data served to infer land-ocean linkages of terrigenous sediment supply in terms of major sources and modes of sediment transport within an over-regional context. This is based on an integrated approach dealing with grain-size analysis, bulk mineralogy and clay mineralogy in combination with statistical data evaluation (end-member modelling of grain-size data, fuzzy cluster analysis of mineralogical data). The findings on clay mineralogy served to update those of earlier work extracted from the literature. Today, two processes of terrigenous sediment supply prevail in the study area: far-distance aeolian sediment supply to the pelagic North Pacific, and hemipelagic sediment dispersal from nearby land sources via ocean currents along the continental margins and island arcs. Aeolian particles show the finest grain sizes (clay and fine silt), whereas hemipelagic sediments have high abundances of coarse silt. Exposed sites on seamounts and the continental slope are partly swept by strong currents, leading to residual enrichment of fine sand. Four sediment sources can be distinguished on the basis of distinct index minerals revealed by statistical data analysis: dust plumes from central Asia (quartz, illite), altered materials from the volcanic regions of Kamchatka and the Aleutian Arc (smectite), detritus from the Alaskan Cordillera (chlorite, hornblende), and fluvial detritus from far-eastern Siberia and the Alaska mainland (quartz, feldspar, illite). These findings confirm those of former studies but considerably expand the geographic range of this suite of proxies as far south as 39°N in the open North Pacific. The present integrated methodological approach proved useful in identifying the major modern processes of terrigenous sediment supply to the study region. This aspect deserves attention in

  5. 白令海和西北冰洋表层沉积物磁化率特征初步研究%Magnetic susceptibility characteristics of surface sediments in Bering Sea and western Arctic Ocean:preliminary results

    Institute of Scientific and Technical Information of China (English)

    汪卫国; 戴霜; 陈莉莉; 吴日升; 余兴光

    2014-01-01

    The mass-dependent magnetic susceptibility (χ)with low and high frequency,anhysteretic susceptibility (χARM )and temperature-dependent susceptibility (k-T )of 61 surface sediment samples obtained from Bering Sea and western Arctic Ocean were measured with an attempt to find the composition,province and transport of mag-netic minerals,which is helpful to accurately decipher the paleo-climate and environmental information recorded by the magnetic parameters in Arctic area.The results show that theχvalues of surface sediments have an evident re-gional difference.Theχvalues are commonly higher in Bering Sea than that in Chukchi Sea,and they are the low-est in the plains and ridges of high western Arctic Ocean.Theχvalues are the highest off the Yukon River estuary and to the south of St.Lawrence Island in Bering Sea shelf,decreasing northward and south-westward.Theχval-ues are relatively higher in the central-eastern Chukchi Sea shelf than that off the Alaskan coast.The χARM share the common variation trends ofχ,however,the frequency-dependent susceptibility changes oppositely to that ofχ. The analysis of k-T shows that the magnetic mineral in surface sediments in Aleutian Basin is maghemite,and off the Yukon River estuary and to the south of St.Lawrence Island is magnetite,and both maghemite and magnetite occur in the western shelf of Bering Sea and central-eastern shelf of Chukchi Sea.The magnetic mineral of surface sediment off the Alaskan coast is pyrite,while in the slope,plains and ridges of high western Arctic Ocean,the magnetic minerals are greigite and pyrite,but the content of greigite is higher in high latitude.The regional distri-bution of magnetic minerals in surface sediments is controlled by the sources of sediments,currents and bottom en-vironments.The maghemite in the shelf of Bering Sea and Chukchi Sea is from the Asian main land,and the mag-netite in eastern Bering Sea shelf is from the watershed of Yukon River.Pyrite off the Alaskan coast

  6. 楚科奇海和白令海的海洋低温微生物调查%THE SURVEY OF MARINE MICROORGANISMS IN LOW TEMPERATURES OF CHUKCHI AND BERING SEA

    Institute of Scientific and Technical Information of China (English)

    曾胤新; 陈波; 蔡明红; 何剑锋

    2001-01-01

    Investigations of total number of marine microbes in low temperatures of Chukchi Sea and Bering sea were conducted during the summer time in north hemisphere. In Chukchi Sea the detection rates of marine bacteria and fungi were 100% and more than 94%, respectively. And the quantity of marine bacteria generally was more than 103 cells/cm3, and that of marine fungi usually 10-103 cells/cm3. In most investigation sites marine bacterial total numbers were higher than marine fungal total numbers. There are abundant marine microorganisms distributing in the areas from surface water to deeper layers of 10m or 30m depth in Chukchi Sea. Results showed that there were large differences of marine microbial total numbers between different sampling sites, and the melt sea ice and salinity in sea water were probably two important factors affecting the marine microbial amounts in Chukchi Sea. As to marine bacteria in Bering sea, their detection rates were 100% and their amounts were generally 102—103 cells/cm3. For marine fungi, their detection rates were more than 84% and their amounts generally 102-103 cells/cm3. Similar to the situation in Chukchi Sea, there were fairly large differences of marine microbial total numbers between different sampling sites in Bering Sea, too.The investigation results proved that a large number of marine microbes in low temperatures lived in Chukchi and Bering Sea. Among the marine bacteria studied, 81% of bacteria from Chukchi Sea and 88.9% of bacteria from Bering sea can grow well in low temperatures no higher than 10℃. And some of these marine bacteria can utilize starch or cellulose as carbon source for their growth. These microbes can provide abundant materials for further exploiting and developing the marine microbe resources in low temperature.%在1999年北极夏季期间对楚科奇海和白令海的海洋低温微生物进行了调查。在楚科奇海,海洋细菌和海洋真菌的检出率分别为100%和>94%,其相

  7. The cross-shelf exchange of surface nutrients in the Bering Sea elucidated from 228Ra tracer%白令海表层营养盐水平输送的镭-228示踪

    Institute of Scientific and Technical Information of China (English)

    邢娜; 陈敏; 黄奕普; 邱雨生

    2011-01-01

    Surface water in the Bering Sea was collected in July—September 1999 for 22BRa measurements and used as a tracer for the cross-shelf exchange of nutrients. The specific activity of surface 2eBRa ranges from below detection to 0.81 Bq/m3 , which is lower than that reported in the western shelves of the Arctic Ocean. The spatial distribution of 228 Ra and 228 Ra/226 Ra)A. R. shows an increase from the central basin to the northeastern shelf. The relationship between 228Ra/226 Ra)A.R. and salinity indicates the influence of the Bering gyre, the Bering Slope Current and the Alaska Coastal Current on 228Ra and 228Ra/226Ra)A.R. Based on a one-dimensional steady state model of 228Ra, the horizontal eddy diffusion coefficient in study areas was calculated to be 1.9 × 108 m2/d. The horizontal exchange fluxes of nutrients from the central basin to the northeastern shelf were estimated by combining the horizontal eddy diffusion coefficient and the spatial gradients of nutrients. The surface horizontal input of nitrate to the northeastern shelf only contributed a small fraction to the new production in the northeastern Bering Sea shelf waters, indicating the importance of other nutrient input pathways in supporting new production on the northeastern Bering shelf.%对白令海表层海水228 Ra的分析表明,白令海表层海水228Ra比活度从低于检测限变化至0.81 Bq/m3,低于西北冰洋陆架区的报道值.表层水228Ra比活度和228Ra/226Ra)A.R.的空间分布均呈现由西南部中心海盆向东北部陆架区增加的趋势.由228Ra/226Ra)A.R.和盐度的关系揭示出白令海环流、白令海陆坡流和阿拉斯加沿岸流对228Ra和228Ra/226Ra)A.R.分布有明显影响.运用一维稳态扩散模型计算出白令海由中心海盆向东北部陆架方向上水体混合的水平涡动扩散系数为1.9 ×108m2/d.结合海盆-陆架界面营养盐的水平浓度梯度,估算得硝酸盐、活性磷酸盐和活性硅酸盐由白令海中心海盆

  8. Bering Mission Navigation Method

    DEFF Research Database (Denmark)

    Betto, Maurizio; Jørgensen, John Leif; Jørgensen, Peter Siegbjørn;

    2003-01-01

    "Bering", after the name of the famous Danish explorer, is a near Earth object (NEO) and main belt asteroids mapping mission envisaged by a consortium of Danish universities and research institutes. To achieve the ambitious goals set forth by this mission, while containing the costs and risks, "B......, "Bering" sports several new technological enhancements and advanced instruments under development at the Technical University of Denmark (DTU). The autonomous on-board orbit determination method is part of them and it is described in this paper....

  9. Sustaining the Bering Ecosystem: A Social Science Research Plan

    Science.gov (United States)

    Fitzhugh, B.; Huntington, H. P.; Pete, M. C.; Sepez, J. A.

    2007-12-01

    The Bering Sea is changing from an ice-dominated to an increasingly open water system. The over-arching goal of the NSF-supported Bering Ecosystem Study (BEST) is to understand the effects of climate variability and change on the Bering Sea ecosystem. To the people who are simultaneously a part of that ecosystem and rely on its productivity for life and work, climate change and its effects are among the top concerns. Sustaining the Bering Ecosystem articulates a vision and approaches for social science research as a component of the BEST Program (www.arcus.org/bering). This science plan seeks to initiate research to elucidate the dynamic relationship between the Bering Sea ecosystem and the humans who constitute an integral component of that system. To do so, this plan delineates a research program focused on three broad themes: 1. Impacts on humans: how past, current, and possible future changes in the Bering Sea ecosystem affect the health and well-being of people living and depending on this region for subsistence, employment, and cultural survival. 2. Human impacts: how changing human uses of the Bering Sea region affect the natural cycles of this ecosystem by moderating and/or accelerating systemic changes. 3. Dynamics of human and non-human natural systems: how the human-environmental dynamic has changed through time and may change in the future due to internal and external opportunities and pressures. These themes are developed in the context of a community-driven approach based on the concerns, goals, and interests of Bering Sea residents and other stakeholders of the region. This plan has been drafted through the collaboration of Bering Sea residents (primarily Alaska Natives) and non-resident stakeholders, social scientists, and natural scientists to focus efforts around research questions important to stakeholders, which in various ways center on issues of sustainability (of resources, economic opportunities, ways of life, and culture itself). The

  10. Bering-Okhotsk Seal Survey (BOSS) Color Imagery (2012-13)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — US surveys were conducted of the Bering Sea pack ice for bearded, spotted, ribbon, and ringed seals using digital cameras and thermal imagers mounted in the belly...

  11. Bering-Okhotsk Seal Survey (BOSS) Identified Hot Spots (2012-13)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — US surveys were conducted of the Bering Sea pack ice for bearded, spotted, ribbon, and ringed seals using digital cameras and thermal imagers mounted in the belly...

  12. CALIBRATION OF MG/CA THERMOMETRY OF THE BENTHIC FORAMINIFERA FROM THE BERING SEA%白令海底栖有孔虫壳体镁钙比值对水团温度的响应

    Institute of Scientific and Technical Information of China (English)

    叶黎明; 邱中炎; 雷吉江

    2012-01-01

    The Mg/Ca ratio of benthic foraminiferal shells was often used as a paleo-temperature proxy for the deep water mass. In this study, we used the Mg/Ca and δ18 O of the benthic foraminifera Uvigerina peregrine to calibrate the Mg/Ca thermometry so as to reveal its feasibility in the Bering Sea. The results show that the calcification temperature calculated with δ18O is much lower than the modern temperature of the water mass, and can not objectively reflect the control of temperature over the Mg/Ca. There is no evidence to relate the Mg/Ca with the modern temperature of water mass in the region if the water depth is shallower than 150 m. In the deep sea, however, a good exponential function expressed as Mg/Ca = 0. 69 * e0.43*T was discovered with a standard error of 0. 2 ℃and the Mg/Ca-temperature sensitivity may reach 43%℃‐1at low temperature in the Bering Sea.%底栖有孔虫壳体Mg/Ca是重建深层水团古温度的主要指标.通过分析表层沉积物样品中底栖有孔虫Uvigerina peregrina壳体的Mg/Ca和δ18 O,探讨了“Mg/Ca古温度重建方法”在白令海低温水体中的可行性及其转换函数.结果表明,利用U.peregrina壳体δ18 O换算的“结壳温度”明显低于“现代水团温度”,不能客观反映温度对Mg/Ca的控制作用;可能受季节性变化的影响,水深小于150 m样品中U.peregrina壳体的Mg/Ca与“现代水团温度”之间并没有表现出明显的相关性,但是,在深海区两者之间却呈现出良好的指数关系:Mg/Ca=0.69*e0.43*T.该公式指出白令海低温水体中Mg/Ca对温度的敏感性约为43%℃-1,由其估算的温度误差约为0.2℃.

  13. A comparison of ringed and bearded seal diet, condition and productivity between historical (1975-1984) and recent (2003-2012) periods in the Alaskan Bering and Chukchi seas

    Science.gov (United States)

    Crawford, Justin A.; Quakenbush, Lori T.; Citta, John J.

    2015-08-01

    Reductions in summer sea ice in the Chukchi and Beaufort seas are expected to affect what has been an ice-adapted marine food web in the Pacific Arctic. To determine whether recent decreases in sea ice have affected ice-associated marine predators (i.e., ringed, Pusa hispida, and bearded seals, Erignathus barbatus) in the Bering and Chukchi seas we compared diet, body condition, growth, productivity, and the proportion of pups harvested (an index of weaning success) for seals of each species harvested by 11 Alaskan villages during two periods; a historical (1975-1984) and a recent period (2003-2012). We also examined how changes in indices of seal health may be correlated with the reduction of sea ice characteristic of the recent period. For ringed seals ⩾1 year of age, the % frequency of occurrence (%FO) of Arctic cod (Boreogadus saida), walleye pollock (Gadus chalcogramma), rainbow smelt (Osmerus mordax), and Pacific herring (Clupea pallasi) increased from the historic to the recent period, while the %FO of invertebrates decreased for both pups and seals ⩾1 year of age. For bearded seals ⩾1 year of age, the %FO of Arctic cod, pricklebacks, and flatfish increased during the recent period, while the %FO of saffron cod (Eleginus gracilis) decreased for pups. Although invertebrates did not change overall for either age class, decreases occurred in 10 of 24 specific prey categories, for bearded seals ⩾1 year of age; only echiurids increased. The %FO of gastropods and bivalves increased for pups while isopods and one species of shrimp and crab decreased in occurrence. During the recent period ringed seals grew faster, had thicker blubber, had no change in pregnancy rate, matured 2 years earlier, and a larger proportion of pups was harvested than during the historical period. Correlations with spring ice concentration showed that the growth and blubber thickness of seals ⩾1 year of age, blubber thickness of pups, and the proportion of pups in the harvest all

  14. PRELIMINARY STUDY ON ABUNDANCE AND BIOMASS OF MEIOFAUNA IN THE BERING SEA IN SUMMER 2010%2010年夏季白令海小型底栖动物丰度与生物量初步研究

    Institute of Scientific and Technical Information of China (English)

    黄丁勇; 王建佳; 林荣澄; 田鹏; 郑新庆

    2016-01-01

    Surface sediments were collected from seven stations in the Bering Sea during the fourth Arctic Chinese Nation-al Arctic Research Expedition in summer 201 0.Fourteen groups of meiofauna were detected in 1 0-cm sediment cores:Nematoda,Copepoda,Polycheata,Kinorhyncha,Amphipoda,Bivalvia,Cumacea,Ostracoda,Tanaidacea, Gastropoda,Isopoda,Ophiura,Tardigrada and others.The average abundance and biomass was 2658.89 ±2452. 86 ind·1 0cm -2 and 1 587.56 ±1 452.65 μg·dwt·1 0cm -2 ,respectively.Maximum abundance and biomass of 71 35.1 2 ±429.43 ind·1 0cm -2 and 4056.42 ±721 .33 μg·dwt·1 0cm -2 ,respectively,were both observed in shallow waters of the Bering shelf.At the same time,minimum abundance and biomass of 56.04 ±39.38 ind·1 0 cm -2 and 87.91 ±85.60 μg·dwt·1 0cm -2 ,respectively,were both observed in deep waters of the western Be-ring Sea basin.Nematoda accounted for 94.81 % of average abundance,followed by Copepoda (3.60%),and 93.44% of meiofauna were found in the upper 6 cm of surface sediments.The similarity index between meiofauna communities in shallow and deep waters was only 30.72%.Abundance in deep waters was an order of magnitude lower than abundance in shallow waters.Abundance and biomass were higher in shallow waters of the Bering shelf than in shallow waters of the China Sea and deep waters of the western Bering Sea basin.Pearson correlations anal-ysis between meiofauna and abiotic parameters indicated that abundance and biomass were negatively correlated with depth,sediment nutrient levels,and several diameter parameters.Meiofauna biomass may be more sensitive to environmental changes than abundance.%2010年7月12—18日,中国第4次北极科考队在白令海以箱式或多管取样器采集7个站位10 cm 长的表层沉积物芯样,并在现场进行了分层处理。室内分析时共检出14个小型底栖动物类群:自由生活海洋线虫(free-living Nematoda)、底栖桡足类(Copepoda)、多毛类(Polycheata)

  15. AFSC/RACE/EcoFOCI: Chlorophyll: variability in spring chlorophyll concentrations and zooplankotn on the eastern Bering Sea shelf - cruise Healy 07-01

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data were collected under NSF Grant # ARC-0722448 ("BEST: Impacts of Sea-ice on the Hydrographic Structure, Nutrients, and Mesozooplankton over the Eastern...

  16. Geological evolution and analysis of confirmed or suspected gas hydrate localities: Volume 10, Basin analysis, formation and stability of gas hydrates of the Aleutian Trench and the Bering Sea

    Energy Technology Data Exchange (ETDEWEB)

    Krason, J.; Ciesnik, M.

    1987-01-01

    Four major areas with inferred gas hydrates are the subject of this study. Two of these areas, the Navarin and the Norton Basins, are located within the Bering Sea shelf, whereas the remaining areas of the Atka Basin in the central Aleutian Trench system and the eastern Aleutian Trench represent a huge region of the Aleutian Trench-Arc system. All four areas are geologically diverse and complex. Particularly the structural features of the accretionary wedge north of the Aleutian Trench still remain the subjects of scientific debates. Prior to this study, suggested presence of the gas hydrates in the four areas was based on seismic evidence, i.e., presence of bottom simulating reflectors (BSRs). Although the disclosure of the BSRs is often difficult, particularly under the structural conditions of the Navarin and Norton basins, it can be concluded that the identified BSRs are mostly represented by relatively weak and discontinuous reflectors. Under thermal and pressure conditions favorable for gas hydrate formation, the relative scarcity of the BSRs can be attributed to insufficient gas supply to the potential gas hydrate zone. Hydrocarbon gas in sediment may have biogenic, thermogenic or mixed origin. In the four studied areas, basin analysis revealed limited biogenic hydrocarbon generation. The migration of the thermogenically derived gases is probably diminished considerably due to the widespread diagenetic processes in diatomaceous strata. The latter processes resulted in the formation of the diagenetic horizons. The identified gas hydrate-related BSRs seem to be located in the areas of increased biogenic methanogenesis and faults acting as the pathways for thermogenic hydrocarbons.

  17. Oceanographic profile plankton, nitrate, silicate and other measurements collected using net and high resolution CTD in the Pacific, Bering, Tsugaru Strait, and Okhotsk from 1988 to 1998 (NODC Accession 0000824)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Plankton and nutrients data were collected using net and CTD casts from the Hokusei Maru in the Sea of Okhotsk, NW Pacific (limit-180), and Bering Sea from 08 March...

  18. Physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201512S in the Arctic Ocean, Beaufort Sea and Bering Sea from 2015-09-27 to 2015-11-10 (NCEI Accession 0156185)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0156185 includes physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201512S in the Arctic Ocean, Beaufort Sea and...

  19. Biological, chemical and other data collected aboard the HEALY during cruise HLY1201 in the Arctic Ocean, Beaufort Sea and Bering Sea from 2012-08-09 to 2012-08-25 (NODC Accession 0116859)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0116859 includes biological, chemical, optical and physical data collected aboard the HEALY during cruise HLY1201 in the Arctic Ocean, Beaufort Sea...

  20. DY1207 Bering Sea ME70

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Midwater Assessment and Conservation Engineering (MACE) Program of the Alaska Fisheries Science Center (AFSC) have conducted summer surveys to...

  1. Counts of Alaska Steller sea lion adult and juvenile (non-pup) conducted on rookeries and haul-outs in Alaska Aleutian Islands, Bering Sea, and others from 1904-01-01 to 2015-07-18 (NCEI Accession 0128190)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains counts of adult and juvenile (non-pup) Steller sea lions on rookeries and haul-outs in Alaska made between 1904 and 2015. Non-pup counts have...

  2. The distribution and status of sea otters in Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The original distribution of sea otters, Enhydra lutris (L), included the coastal area of the North Pacific Ocean and Bering Sea from Kamchatka south to Hokkaido...

  3. NODC Standard Product: International ocean atlas Volume 12 - Climatic atlas of the North Pacific Seas 2009 (NODC Accession 0098576)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Atlas contains monthly climatic charts of temperature, salinity, and oxygen at the sea surface and at standard depth levels for the Bering Sea, Sea of Okhotsk,...

  4. Walrus used and available resource units for northeast Chukchi Sea, 2008-2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Sea ice loss represents a stressor to the Pacific walrus (Odobenus rosmarus divergens), which feeds on benthic macroinvertebrates in the Bering and Chukchi seas....

  5. Partial pressure (or fugacity) of carbon dioxide, salinity and SEA SURFACE TEMPERATURE collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea and others from 2010-05-07 to 2013-06-25 (NODC Accession 0109901)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0109901 includes Surface underway data collected from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea, Bering Sea, Caribbean Sea, Cordell Bank...

  6. Characteristics of pCO2 in surface water of the Bering Abyssal Plain and their effects on carbon cycle in the western Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    CHEN Liqi; GAO Zhongyong; WANG Weiqiang; YANG Xulin

    2004-01-01

    Characteristics of the pCO2 distribution in surface water of the Bering Abyssal Plain and their relationships with the ambient hydrological conditions were discussed using variations of the partial pressure of CO2 in surface water of the Bering Abyssal Plain and the Chukchi Sea. Data in this study are from a field investigation during the First Chinese National Arctic Research Expedition in 1999. Compared to the high productivity in the Bering Continental Shelf, much lower levels of chlorophyll a were observed in the Bering Abyssal Plain. The effect of hydrological factors on the pCO2 distribution in surface seawater of the Plain in summer has become a major driving force and dominated over biological factors. The Plain also presents a High Nutrient Low Chlorophyll (HNLC). In addition, the pCO2 distribution in the Bering Abyssal Plain has also been found to be influenced from the Bering Slope Current which would transform to the Anadyr Current when it inflows northwestward over the Plain. The Anadyr Current would bring a high nutrient water to the western Arctic Ocean where local nutrients are almost depleted in the surface water during the summer time. Resupplying nutrients would stimulate the growth of phytoplankton and enhance capacity of absorbing atmospheric CO2 in the surface water. Otherwise, in the Bering Sea the dissolved inorganic carbon brought from freshwater are not deposited down to the deep sea water but most of them would be transported into the western Arctic Ocean by the Alaska Coastal Current to form a carbon sink there. Therefore, the two carbon sinks in the western Arctic Ocean, one carried by the Anadyr Current and another by the Alaska Costal Current, will implicate the western Arctic Ocean in global change.

  7. Ecological characteristics of core-use areas used by Bering-Chukchi-Beaufort (BCB) bowhead whales, 2006-2012

    Science.gov (United States)

    Citta, John J.; Quakenbush, Lori T.; Okkonen, Stephen R.; Druckenmiller, Matthew L.; Maslowski, Wieslaw; Clement-Kinney, Jaclyn; George, John C.; Brower, Harry; Small, Robert J.; Ashjian, Carin J.; Harwood, Lois A.; Heide-Jørgensen, Mads Peter

    2015-08-01

    The Bering-Chukchi-Beaufort (BCB) population of bowhead whales (Balaena mysticetus) ranges across the seasonally ice-covered waters of the Bering, Chukchi, and Beaufort seas. We used locations from 54 bowhead whales, obtained by satellite telemetry between 2006 and 2012, to define areas of concentrated use, termed "core-use areas". We identified six primary core-use areas and describe the timing of use and physical characteristics (oceanography, sea ice, and winds) associated with these areas. In spring, most whales migrated from wintering grounds in the Bering Sea to the Cape Bathurst polynya, Canada (Area 1), and spent the most time in the vicinity of the halocline at depths whales generally left in July, when copepods are expected to descend to deeper depths. Between 12 July and 25 September, most tagged whales were located in shallow shelf waters adjacent to the Tuktoyaktuk Peninsula, Canada (Area 2), where wind-driven upwelling promotes the concentration of calanoid copepods. Between 22 August and 2 November, whales also congregated near Point Barrow, Alaska (Area 3), where east winds promote upwelling that moves zooplankton onto the Beaufort shelf, and subsequent relaxation of these winds promoted zooplankton aggregations. Between 27 October and 8 January, whales congregated along the northern shore of Chukotka, Russia (Area 4), where zooplankton likely concentrated along a coastal front between the southeastward-flowing Siberian Coastal Current and northward-flowing Bering Sea waters. The two remaining core-use areas occurred in the Bering Sea: Anadyr Strait (Area 5), where peak use occurred between 29 November and 20 April, and the Gulf of Anadyr (Area 6), where peak use occurred between 4 December and 1 April; both areas exhibited highly fractured sea ice. Whales near the Gulf of Anadyr spent almost half of their time at depths between 75 and 100 m, usually near the seafloor, where a subsurface front between cold Anadyr Water and warmer Bering Shelf Water

  8. 白令海与西北冰洋表层沉积物中四醚膜类脂物研究及其生态和环境指示意义%Spatial Distribution Patterns of GDGTs in the Surface Sediments from the Bering Sea and Arctic Ocean and Their Environmental Significances

    Institute of Scientific and Technical Information of China (English)

    王寿刚; 王汝建; 陈建芳; 陈志华; 程振波; 汪卫国; 黄元辉

    2013-01-01

    Biomarker Glycerol Dialkyl Glycerol Tetraethers (GDGTs) was analyzed in 65 surface sediments from the Bering Sea and western Arctic Ocean recovered during the 3rd and 4rd Chinese National Arctic Expeditions. The distribution patterns of isoprenoid and branched GDGTs concentration are divided by the Chukchi and Beaufort Sea Slope. GDGTs concentration is higher in the south of the slope than that in the north, which is controlled by water column productivity and terrestrial organic matter input. GDGTs based BIT suggests that terrestrial organic matter input increases from the north Chukchi Sea to Alpha Ridge, compared with marine organic matter, which is consistent with the results retrieved from organic carbon isotope ratios, suggesting that BIT is a reliable proxy in the Arctic Ocean. Sea Surface Temperatures ( SST) derived by TEXL86 are not related to modern annual or summer mean SST, probably because of the mixed signal from terrestrial isprenoid GDGTs and low archaeal productivity in high Arctic region. Cyclisation ratio of Branched Tetraethers (CBT) show strong increase from seasonal sea ice area to permanent sea ice area, which may prove that CBT is sensitive to sea ice coverage. However, its mechanism remained unclear. Reconstructed terrestrial annual mean atmospheric temperature (MAT) and soil pH from branched GDGTs based CBT and Methylation index of Branched Tetraether ( MBT) show extremely variability, which is probably affected by complicated sediment sources and soil mixing in transportation process.%通过对中国第3次和第4次北极考察在白令海和西北冰洋采集的65个表层样沉积物中生物标记物四醚膜类脂物(GDGTs)的研究,发现西北冰洋表层沉积物中类异戊二烯和支链GDGTs的浓度分布大致以楚科奇海和波弗特海的陆坡为界线,呈现南高北低的特征,这一特征主要与水体生产力和陆源有机质的输入量有关.基于GDGTs的陆源输入指数BIT显示,从楚科奇海北部到

  9. Partial pressure (or fugacity) of carbon dioxide, salinity and SEA SURFACE TEMPERATURE collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea and others from 1994-11-04 to 2012-08-31 (NODC Accession 0083189)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0083189 includes chemical, physical and underway - surface data collected from NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea, Bering Sea,...

  10. Partial pressure (or fugacity) of carbon dioxide, salinity and SEA SURFACE TEMPERATURE collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and others from 2011-05-17 to 2012-10-26 (NODC Accession 0083197)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0083197 includes chemical, physical and underway - surface data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of...

  11. AFSC/RACE/MACE: Results of 2012 Chukchi Sea Acoustic/Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We conducted acoustic-trawl (AT) surveys of the Alaska northern Bering and Chukchi Seas during ice-free periods with a focus on Arctic cod (Boreogadus saida), a key...

  12. 75 FR 81921 - Fisheries of the Exclusive Economic Zone Off Alaska; Steller Sea Lion Protection Measures for the...

    Science.gov (United States)

    2010-12-29

    ... published in the Federal Register on December 13, 2010 (75 FR 77535), to implement Steller sea lion... corrections revise coordinates for Steller sea lion sites, revise footnotes, add degree symbols, add lines... Economic Zone Off Alaska; Steller Sea Lion Protection Measures for the Bering Sea and Aleutian...

  13. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Arctic Ocean, Beaufort Sea and others from 2002-08-22 to 2002-10-10 (NODC Accession 0112355)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112355 includes biological, chemical, discrete sample, physical and profile data collected from MIRAI in the Arctic Ocean, Beaufort Sea, Bering Sea...

  14. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea and others from 2011-04-13 to 2011-12-28 (NCEI Accession 0144305)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144305 includes Surface underway data collected from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea, Bering Sea, Gulf of Alaska, Hawaiian...

  15. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2013-08-06 to 2013-10-29 (NCEI Accession 0144346)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144346 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea and Northwest Passage from 2013-08-06 to...

  16. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the MELVILLE in the Arabian Sea, Bay of Bengal and others from 1972-07-18 to 1978-04-28 (NODC Accession 0117677)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0117677 includes chemical, discrete sample, physical and profile data collected from MELVILLE in the Arabian Sea, Bay of Bengal, Bering Sea, Gulf of...

  17. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2014-05-05 to 2014-08-30 (NCEI Accession 0144350)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144350 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska, Gulf of...

  18. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2011-05-27 to 2011-12-16 (NCEI Accession 0144345)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144345 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska, Gulf of...

  19. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2015-07-14 to 2015-10-28 (NCEI Accession 0144530)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144530 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska, Gulf of...

  20. Coastal Bathymetry of the Bering, Chuckhi, and Beaufort Seas

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Bathymetric contours were generated from soundings collected by National Ocean Service vessels from ~1900 to ~1971. The 1:250,000 maps are available for U.S....

  1. Comparing the impacts of Miocene-Pliocene changes in inter-ocean gateways on climate: Central American Seaway, Bering Strait, and Indonesia

    Science.gov (United States)

    Brierley, Chris M.; Fedorov, Alexey V.

    2016-06-01

    Changes in inter-ocean gateways caused by tectonic processes have been long considered an important factor in climate evolution on geological timescales. Three major gateway changes that occurred during the Late Miocene and Pliocene epochs are the closing of the Central American Seaway (CAS) by the uplift of the Isthmus of Panama, the opening of the Bering Strait, and the closing of a deep channel between New Guinea and the Equator. This study compares the global climatic effects of these changes within the same climate model framework. We find that the closure of the CAS and the opening of the Bering Strait induce the strongest effects on the Atlantic meridional overturning circulation (AMOC). However, these effects potentially compensate, as the closure of the CAS and the opening of the Bering Strait cause similar AMOC changes of around 2 Sv (strengthening and weakening respectively). Previous simulations with an open CAS consistently simulated colder oceanic conditions in the Northern Hemisphere - contrasting with the evidence for warmer sea surface temperatures 10-3 million years ago. Here we argue that this cooling is overestimated because (a) the models typically simulated too strong an AMOC change not yet in equilibrium, (b) used a channel too deep and (c) lacked the compensating effect of the closed Bering Strait - a factor frequently ignored despite its potential influence on northern high latitudes and ice-sheet growth. Further, we discuss how these gateway changes affect various climatic variables from surface temperature and precipitation to ENSO characteristics.

  2. Bering Sea wilderness study area, Bering Sea National Wildlife Refuge, Second Judicial Division, Alaska, wilderness study report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Wilderness study report including notice of public hearing, history, description, development, management, mailing list, and transcript of hearing.

  3. On the dynamics of strait flows: an ocean model study of the Aleutian passages and the Bering Strait

    Science.gov (United States)

    Ezer, Tal; Oey, Lie-Yauw

    2013-03-01

    A high-resolution numerical ocean circulation model of the Bering Sea (BS) is used to study the natural variability of the BS straits. Three distinct categories of strait dynamics have been identified: (1) Shallow passages such as the Bering Strait and the Unimak Passage have northward, near barotropic flow with periodic pulses of larger transports; (2) wide passages such as Near Straits, Amukta Pass, and Buldir Pass have complex flow patterns driven by the passage of mesoscale eddies across the strait; and (3) deep passages such as Amchitka Pass and Kamchatka Strait have persistent deep return flows opposite in direction to major surface currents; the deep flows persist independent of the local wind. Empirical orthogonal function analyses reveal the spatial structure and the temporal variability of strait flows and demonstrate how mesoscale variations in the Aleutian passages influence the Bering Strait flow toward the Arctic Ocean. The study suggests a general relation between the barotropic and baroclinic Rossby radii of deformations in each strait, and the level of flow variability through the strait, independent of geographical location. The mesoscale variability in the BS seems to originate from two different sources: a remote origin from variability in the Alaskan Stream that enters the BS through the Aleutian passages and a local origin from the interaction of currents with the Bowers Ridge in the Aleutian Basin. Comparisons between the flow in the Aleutian passages and flow in other straits, such as the Yucatan Channel and the Faroe Bank Channel, suggest some universal topographically induced dynamics in strait flows.

  4. 76 FR 27287 - Port Access Route Study: In the Bering Strait; Extension of Comment Period

    Science.gov (United States)

    2011-05-11

    ... of Study and request for comments for the Port Access Route Study: In the Bering Strait (75 FR 68568..., 2008, issue of the Federal Register (73 FR 3316). This notice is issued under authority of 33 U.S.C... SECURITY Coast Guard 33 CFR Part 167 Port Access Route Study: In the Bering Strait; Extension of...

  5. 76 FR 2027 - Fisheries of the Exclusive Economic Zone Off Alaska; Steller Sea Lion Protection Measures for the...

    Science.gov (United States)

    2011-01-12

    ... INFORMATION: An interim final rule was published in the Federal Register on December 13, 2010 (75 FR 77535... regulatory tables was published in the Federal Register on December 29, 2010 (75 FR 53272). The public... Economic Zone Off Alaska; Steller Sea Lion Protection Measures for the Bering Sea and Aleutian...

  6. Partial pressure of carbon dioxide (pCO2), temperature, salinity and other variables collected from surface underway observations using shower head equilibrator, carbon dioxide gas detector, and other instruments from NOAA Ship Oscar Dyson in the Bering Sea and coast of Alaska from 2014-03-03 to 2014-08-13 (NCEI Accession 0132046)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains underway measurements of pCO2, salinity, sea surface temperature, and other parameters collected in 2014 on board NOAA Ship Oscar...

  7. Surge dynamics on Bering Glacier, Alaska, in 2008–2011

    Directory of Open Access Journals (Sweden)

    M. Braun

    2012-11-01

    Full Text Available A surge cycle of the Bering Glacier system, Alaska, is examined using observations of surface velocity obtained using synthetic aperture radar (SAR offset tracking, and elevation data obtained from the University of Alaska Fairbanks LiDAR altimetry program. After 13 yr of quiescence, the Bering Glacier system began to surge in May 2008 and had two stages of accelerated flow. During the first stage, flow accelerated progressively for at least 10 months and reached peak observed velocities of ~ 7 m d−1. The second stage likely began in 2010. By 2011 velocities exceeded 9 m d−1 or ~ 18 times quiescent velocities. Fast flow continued into July 2011. Surface morphology indicated slowing by fall 2011; however, it is not entirely clear if the surge is yet over. The quiescent phase was characterized by small-scale acceleration events that increased driving stresses up to 70%. When the surge initiated, synchronous acceleration occurred throughout much of the glacier length. Results suggest that downstream propagation of the surge is closely linked to the evolution of the driving stress during the surge, because driving stress appears to be tied to the amount of resistive stress provided by the bed. In contrast, upstream acceleration and upstream surge propagation is not dependent on driving stress evolution.

  8. Dendrochronology and late Holocene history of Bering piedmont glacier, Alaska

    Science.gov (United States)

    Wiles, G.C.; Post, A.; Muller, E.H.; Molnia, B.F.

    1999-01-01

    Fluctuations of the piedmont lobe of Bering Glacier and its sublobe Steller Glacier over the past two millennia are reconstructed using 34 radiocarbon dates and tree-ring data from 16 sites across the glaciers' forelands. The general sequence of glacial activity is consistent with well-dated fluctuations of tidewater and land-terminating glaciers elsewhere along the Gulf of Alaska. Extensive forested areas along 25 km of the Bering ice margin were inundated by glacio-lacustrine and glacio-fluvial sediments during a probable ice advance shortly before 500 cal yr A.D. Regrowth of forests followed the retreating ice as early as the 7th century A.D., with frequent interruptions of tree growth due to outwash aggradation. Forests overrun by ice and buried in outwash indicate readvance about 1080 cal yr A.D. Retreat followed, with ice-free conditions maintained along the distal portions of the forefield until the early 17th century after which the ice advanced to within a few kilometers of its outer Neoglacial moraine. Ice reached this position after the mid-17th century and prior to 200 yr ago. Since the early 20th century, glacial retreat has been punctuated by periodic surges. The record from forests overrun by the nonsurging Steller Lobe shows that this western ice margin was advancing by 1250 A.D., reaching near its outer moraine after 1420 cal yr A.D. Since the late 19th century, the lobe has dominantly retreated.

  9. Age- and sex-specific mortality and population structure in sea otters

    Science.gov (United States)

    Bodkin, J.L.; Burdin, A.M.; Ryazanov, D.A.

    2000-01-01

    We used 742 beach-cast carcasses to characterize age- and sex-specific sea otter mortality during the winter of 1990-1991 at Bering Island, Russia. We also examined 363 carcasses recovered after the 1989 grounding of the T/V Exxon Valdez, to characterize age and sex composition in the living western Prince William Sound (WPWS) sea otter population. At Bering Island, mortality was male-biased (81%), and 75% were adults. The WPWS population was female-biased (59%) and most animals were subadult (79% of the males and 45% of the females). In the decade prior to 1990-1991 we found increasing sea otter densities (particularly among males), declining prey resources, and declining weights in adult male sea otters at Bering Island. Our findings suggest the increased mortality at Bering Island in 1990-1991 was a density-dependent population response. We propose male-maintained breeding territories and exclusion of juvenile females by adult females, providing a mechanism for potentially moderating the effects of prey reductions on the female population. Increased adult male mortality at Bearing Island in 1990-1991 likely modified the sex and age class structure there toward that observed in Prince William Sound.

  10. Bering-Okhotsk Seal Survey (BOSS) On-Effort Flight Tracks (2012-13)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Aerial surveys were flown during the spring of 2012 and 2013 as part of the Bering Okhotsk Seal Surveys (BOSS) project to gather data on distribution and abundance...

  11. Assessment of clinical pathology and pathogen exposure in sea otters (Enhydra lutris) bordering the threatened population in Alaska

    Science.gov (United States)

    Goldstein, T.; Gill, V.A.; Tuomi, P.; Monson, D.; Burdin, A.; Conrad, P.A.; Dunn, J.L.; Field, C.; Johnson, Chad; Jessup, David A.; Bodkin, J.; Doroff, A.M.

    2011-01-01

    Northern sea otter (Enhydra lutris kenyoni) abundance has decreased dramatically over portions of southwest Alaska, USA, since the mid-1980s, and this stock is currently listed as threatened under the Endangered Species Act. In contrast, adjacent populations in south central Alaska, USA, and Russia have been stable to increasing during the same period. Sea otters bordering the area classified in the recent decline were live-captured during 2004-2006 at Bering Island, Russia, and the Kodiak Archipelago, Alaska, USA, to evaluate differences in general health and current exposure status to marine and terrestrial pathogens. Although body condition was lower in animals captured at Bering Island, Russia, than it was at Kodiak, USA, clinical pathology values did not reveal differences in general health between the two regions. Low prevalences of antibodies (,5%) were found in Kodiak, USA, and on Bering Island, Russia, to Toxoplasmagondii, Sarcocystis neurona, and Leptospira interrogans. Exposure to phocine herpesvirus-1 was found in both Kodiak, USA (15.2%), and Bering Island, Russia (2.3%). Antibodies to Brucella spp. were found in 28% of the otters tested on Bering Island, Russia, compared with only 2.7% of the samples from Kodiak, USA. Prevalence of exposure to Phocine distemper virus (PDV) was 41% in Kodiak, USA, but 0% on Bering Island, Russia. Archived sera from southwest and south-central Alaska dating back to 1989 were negative for PDV, indicating exposure occurred in sea otters in Kodiak, USA, in recent years. Because PDV can be highly pathogenic in nai{dotless}??ve and susceptible marine mammal populations, tissues should be examined to explore the contribution of this virusto otter deaths. Our results reveal an increase in exposure to pathogens in sea otters in Kodiak,Alaska, USA, since the 1990s. ?? Wildlife Disease Association 2011.

  12. Behavior of bowhead whales of the Davis Strait and Bering/Beaufort stocks versus regional differences in human activities. Final report on Phase 2

    International Nuclear Information System (INIS)

    The objectives were to determine (1) whether there are differences in behavior between the Bering/Chukchi/Beaufort and the Davis Strait/Baffin Bay populations and (2), if so, whether the differences might be attributable to the long-term cumulative effects of exposure to the presumed greater amount of human activity in the former area. Phase 1 showed that there are some differences in behavior. The Phase 2 report documents the relative amounts of human activity in the two areas in 1974-86, and evaluates whether regional differences in whale behavior and in human activities may be related. Activities considered include bowhead hunting and other subsistence activities, commercial fishing and shipping, marine seismic exploration, offshore oil exploration, and low-level aircraft flights. Bering/Beaufort bowheads were subjected to at least 3-5 times as much human activity in 1974-86. Most differences in behavior between the two stocks were better explained by environmental or biological factors than by disturbance. However, for bowheads migrating in autumn, regional differences in behavior may be related to the whaling that occurs in the Beaufort Sea in autumn

  13. Coupling and feedback between Pacific sea ice and the Western Pacific pattern

    Science.gov (United States)

    Matthewman, N. J.; Magnusdottir, G.

    2010-12-01

    Coupling between sea ice variability in the Pacific basin and large scale modes of atmospheric variability are examined using weekly averaged data for December-April between 1979 and 2008. We define the large scale patterns of variability for sea ice concentration and 500hPa geopotential height over the Pacific basin and North America using Empirical Orthogonal Functions (EOFs). The patterns associated with the leading two EOFs of sea ice variability are a dipole in sea ice concentration with centers of action in the Bering Sea and Sea of Okhotsk (first EOF, ICE1), and an advance or retreat of sea ice in both seas simultaneously (second EOF, ICE2). Correlation analysis between the 500hPa geopotential height field and the principal component of the ICE2 pattern shows a large non-local response in geopotential height to changes in the ICE2 sea ice pattern. At extratropical latitudes this response in 500hPa geopotential height has two strong centers of action over the Bering Strait and Hudson Bay, with two somewhat weaker centers of action in the subtropics over the Western Pacific Ocean and the Atlantic Ocean. Further analysis suggests this response is due to sea ice in the Bering Sea region of the the ICE2 pattern, rather than the Sea of Okhotsk. This response pattern closely resembles a leading mode of 500hPa geopotential height variability, the Western Pacific (WP) pattern, indicating a coupled relationship between the WP pattern and the overall advance and retreat of sea ice in the Pacific basin. By considering intraseasonal time series of the principal components (indices) associated with the ICE2 and WP patterns, causality and coupling between the two is quantified using a stochastically forced Vector Autoregressive (VAR) model. Fitting the VAR model to observed time series for each index, we find that co-dependence between the ICE2 and WP significantly improves model performance compared with model configurations where dependence in either direction is

  14. Improving estimation of glacier volume change: a GLIMS case study of Bering Glacier System, Alaska

    Directory of Open Access Journals (Sweden)

    M. J. Beedle

    2007-07-01

    Full Text Available The Global Land Ice Measurements from Space (GLIMS project has developed tools and methods that can be employed by analysts to create accurate glacier outlines and resultant measures of glacier extent. To illustrate the importance of accurate glacier outlines and the effectiveness of GLIMS standards we have conducted a case study on Bering Glacier System (BGS, Alaska. BGS is a complex glacier system aggregated from multiple drainage basins, numerous individual ice streams, and many accumulation areas. Published measurements of BGS surface area vary from 1740 to 6200 km2, depending on how the boundaries of this system have been defined. Utilizing GLIMS tools and standards we have completed a new outline and analysis of the area-altitude distribution (hypsometry of BGS using Landsat images from 2000 and 2001. We compared this new outline (3632 km2 with three previous outlines to illustrate the errors that result from the widely varying estimates used in previous analysis of BGS area. The use of different BGS outlines results in highly variable measures of volume change and net balance (bn. Outline variability alone results in a net balance rate range of –1.0 to –3.2 m/yr water equivalent (W.E., a volume change range of –4.2 to –8.2 km3/yr, and a near doubling in contributions to sea level equivalent (SLE, 0.0122 mm/yr to 0.0236 mm/yr. A study of three different models of BGS net balance leads us to favor estimates of bn of –1.2 m/yr W.E. and total volume change of –4.2 km3/yr for the period 1950–2004. These estimates result in a near doubling of contributions to sea level equivalent when compared with previous studies. While current inaccuracies in glacier outlines hinder our ability to fully understand glacier change, there is no reason why our understanding of glacier extents should not be comprehensive and accurate. Such accuracy is possible with the

  15. Gray whale sightings in the Canadian Beaufort Sea, September 2014

    Science.gov (United States)

    Iwahara, Yuka; Fujiwara, Amane; Ito, Keizo; Miyashita, Kazushi; Mitani, Yoko

    2016-06-01

    Gray whales (Eschrichtius robustus) are distributed within the productive neritic and estuarine waters of the North Pacific Ocean, the Bering Sea, and adjacent waters of the Arctic Ocean. They migrate to high-latitude feeding grounds each spring. Their main feeding grounds in the Arctic include the Chirikov Basin, the northeastern Chukchi Sea from Pt. Hope to Cape Lisburne and Pt. Lay to Pt. Barrow, and the northwestern Chukchi Sea along the Chukotka coast. Although sightings are rare in the Canadian Beaufort Sea, we observed three gray whales in two groups in this area in September 2014. A mud plume was observed near one of the whales, suggesting the animal had been feeding. In the Alaskan Beaufort Sea, large-scale monitoring of the distributions of marine mammals has been continuously conducted since 1979; however, there has been less monitoring in the Canadian Beaufort Sea. Therefore, it is necessary to record opportunistic sightings, such as those described here.

  16. Yield response of Bere, a Scottish barley landrace, to cultural practices and agricultural inputs

    Directory of Open Access Journals (Sweden)

    Peter J. Martin

    2011-11-01

    Full Text Available There is very little documented about the response of cereal landraces to modern agricultural practices. Bere is a Scottish barley (Hordeum vulgare L. landrace which is grown in Orkney to supply meal for baking. A recent research programme has improved yields and the security of the Bere harvest, making it possible to supply a new market for grain to produce specialist whiskies. At the start of this research, a survey of Orkney farmers who had grown Bere since the 1980s showed that most had planted it at the traditional time in mid-May, used few inputs and considered the main constraints of the crop to be low yield (2.8 to 3.8 t/ha and susceptibility to lodging. Three years of trials in Orkney between 2003 and 2005 showed very significant increases in grain yield (17-76% and thousand grain weight from planting Bere earlier, in the second half of April. This also had the advantage of an earlier and more secure harvest. Yields showed smaller, but often significant, increases (5-11% from applying mineral fertiliser, growth regulator or fungicide, while combinations of growth regulator and fungicide increased yields from 10- 22%. In spite of usually increasing grain yield, growth regulator did not always control lodging. Although the use of inputs often increased the gross margins of growing Bere, a trial in 2005 showed that early planting was a more cost effective single intervention than either the use of fungicide or growth regulator. By increasing grower profits and reducing harvesting risks, these results have made it viable for more farmers to grow Bere in its region of origin, providing growers and end-users with additional income and contributing to the in situ conservation of this landrace.

  17. Could massive Arctic sea ice export to the North Atlantic be the real cause of abrupt climate change during the last deglaciation?

    Science.gov (United States)

    Coletti, A. J.; Condron, A.

    2015-12-01

    Using a coupled ocean-sea ice model (MITgcm), we investigate whether the break-up and mobilization of thick, multiyear, Arctic sea ice might have supplied enough freshwater to the Nordic Seas to reduce North Atlantic Deep Water (NADW) formation and weaken the Atlantic Meridional Overturning Circulation (AMOC). Numerical simulations of a Last Glacial Maximum (LGM) environment show the potential for sea ice to grow to ~30m thick, storing ~1.41x105 km3 of freshwater as sea ice in the Arctic (this is ~10 times the volume of freshwater stored in the modern-day Arctic). Releasing this volume of sea ice from the Arctic in 1-yr is equivalent to a high-latitude freshwater forcing of ~4.5 Sv, which is comparable (or larger) in magnitude to most meltwater floods emanating from land-based glacial lakes (e.g. Agassiz) during the last deglaciation. Opening of the Bering Strait and Barents Sea are two plausible mechanisms that may have initiated sea ice mobilization. Opening Bering Strait increases sea ice transport through the Fram Strait by 7% and results in a 22% weakening of AMOC for 2000 years and a >3°C warming in the Arctic basin at 800 m depth. Opening Barents Sea to simulate a collapse of the Fennoscandian ice sheet has little impact on Arctic sea ice and freshwater export to the North Atlantic, but weakens AMOC ~8%. In a simulation with both straits open there is a transition to near-modern sea ice circulation pattern and a 24% reduction in AMOC. Experiments with the Bering Strait open and sea ice artificially capped to 10 m show barely any difference to those when sea ice can grow to ~30m, suggesting that changes in topography have a much greater impact on AMOC than the freshwater forcing from sea ice melting in the Nordic Seas.

  18. Assessment of clinical pathology and pathogen exposure in sea otters (Enhydra lutris) bordering the threatened population in Alaska.

    Science.gov (United States)

    Goldstein, Tracey; Gill, Verena A; Tuomi, Pam; Monson, Daniel; Burdin, Alexander; Conrad, Patricia A; Dunn, J Lawrence; Field, Cara; Johnson, Christine; Jessup, David A; Bodkin, James; Doroff, Angela M

    2011-07-01

    Northern sea otter (Enhydra lutris kenyoni) abundance has decreased dramatically over portions of southwest Alaska, USA, since the mid-1980s, and this stock is currently listed as threatened under the Endangered Species Act. In contrast, adjacent populations in south central Alaska, USA, and Russia have been stable to increasing during the same period. Sea otters bordering the area classified in the recent decline were live-captured during 2004-2006 at Bering Island, Russia, and the Kodiak Archipelago, Alaska, USA, to evaluate differences in general health and current exposure status to marine and terrestrial pathogens. Although body condition was lower in animals captured at Bering Island, Russia, than it was at Kodiak, USA, clinical pathology values did not reveal differences in general health between the two regions. Low prevalences of antibodies (neurona, and Leptospira interrogans. Exposure to phocine herpesvirus-1 was found in both Kodiak, USA (15.2%), and Bering Island, Russia (2.3%). Antibodies to Brucella spp. were found in 28% of the otters tested on Bering Island, Russia, compared with only 2.7% of the samples from Kodiak, USA. Prevalence of exposure to Phocine distemper virus (PDV) was 41% in Kodiak, USA, but 0% on Bering Island, Russia. Archived sera from southwest and south-central Alaska dating back to 1989 were negative for PDV, indicating exposure occurred in sea otters in Kodiak, USA, in recent years. Because PDV can be highly pathogenic in naïve and susceptible marine mammal populations, tissues should be examined to explore the contribution of this virus to otter deaths. Our results reveal an increase in exposure to pathogens in sea otters in Kodiak, Alaska, USA, since the 1990 s. PMID:21719822

  19. Improving estimation of glacier volume change: a GLIMS case study of Bering Glacier System, Alaska

    Directory of Open Access Journals (Sweden)

    M. J. Beedle

    2008-04-01

    Full Text Available The Global Land Ice Measurements from Space (GLIMS project has developed tools and methods that can be employed by analysts to create accurate glacier outlines. To illustrate the importance of accurate glacier outlines and the effectiveness of GLIMS standards we conducted a case study on Bering Glacier System (BGS, Alaska. BGS is a complex glacier system aggregated from multiple drainage basins, numerous tributaries, and many accumulation areas. Published measurements of BGS surface area vary from 1740 to 6200 km2, depending on how the boundaries of this system have been defined. Utilizing GLIMS tools and standards we have completed a new outline (3630 km2 and analysis of the area-altitude distribution (hypsometry of BGS using Landsat images from 2000 and 2001 and a US Geological Survey 15-min digital elevation model. We compared this new hypsometry with three different hypsometries to illustrate the errors that result from the widely varying estimates of BGS extent. The use of different BGS hypsometries results in highly variable measures of volume change and net balance (bn. Applying a simple hypsometry-dependent mass-balance model to different hypsometries results in a bn rate range of −1.0 to −3.1 m a−1 water equivalent (W.E., a volume change range of −3.8 to −6.7 km3 a−1 W.E., and a near doubling in contributions to sea level equivalent, 0.011 mm a−1 to 0.019 mm a−1. Current inaccuracies in glacier outlines hinder our ability to correctly quantify glacier change. Understanding of glacier extents can become comprehensive and accurate. Such accuracy is possible with the increasing volume of satellite imagery of glacierized regions, recent advances in tools and standards, and dedication to this important task.

  20. Physical oceanographic mooring data (temperature, salinity, velocity including ADCP ice tracking) collected from Bering Strait Moorings A2,A4, A3 in Bering Strait from 2013-07-05 to 2014-07-02 (NCEI Accession 0156230)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data from moorings deployed in Bering Strait from summer 2013 to summer 2014. Mooring deployments were funded by the ONR award...

  1. Physical oceanographic mooring data (temperature, salinity, velocity including ADCP ice tracking) collected from Bering Strait Moorings A2, A3, A4 in Bering Strait from 2014-07-02 to 2015-07-05 (NCEI Accession 0155760)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data from moorings deployed in Bering Strait from summer 2014 to summer 2015. Mooring deployments were funded by the NSF-Arctic Observing...

  2. AFSC/RACE/SAP/Armistead: 1975 - 2016 eastern Bering Sea Crab Distribution For Web

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Resource Assessment and Conservation Engineering Division (RACE) of the Alaska Fisheries Science Center (AFSC) conducts bottom trawl surveys to monitor the...

  3. AFSC/NMML: North Pacific Right Whale Vessel Surveys in the Southeastern Bering Sea, 2007 - 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The North Pacific right whale (NPRW) was heavily hunted between the 17th and the 20th centuries. Protection was supposedly afforded by international treaties in the...

  4. AFSC/ABL: Gulf of Alaska and Bering Sea Capelin Microsatellite data, 2005 & 2007

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Capelin are important forage fish in Alaska for marine mammals, birds, and predatory fish. Capelin prefer cold water and are very sensitive to changing...

  5. AFSC/RACE/GAP/Orr: Bering Sea Slope groundfish surveys Identification Confidence

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This report includes an identification confidence matrix for all fishes and invertebrates identified from the EBS slope triennial and biennial surveys from 1976...

  6. EBSSED database-Surficial sediments of the eastern Bering Sea continental shelf

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In order to facilitate descriptions of groundfish habitat over a large portion of the EBS shelf, the NMFS/AFSC has assembled a single comprehensive database of the...

  7. AFSC/ABL: Genetic Analysis of Immature Bering Sea Chum Salmon: Part I. Baseline Evaluation

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chum salmon populations from across their geographic distribution have been analyzed with a set of SNP and microsatellite markers. As is typical for chum salmon...

  8. Eastern Bering Sea Acoustic-Trawl Survey of Walleye Pollock (DY1006, ME70)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of the Alaska Fisheries Science Center (AFSC; NOAA National Marine Fisheries Service) conducted...

  9. H08851: NOS Hydrographic Survey, Unspecified State, BERING SEA, Unknown Date

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  10. H07949: NOS Hydrographic Survey , Bering Sea, Alaska, 1953-09-01

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  11. AFSC/NMML: Distribution of cetaceans in the Bering, Chukchi, and Beaufort Seas, 2010-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of several inter-agency agreements between the National Marine Mammal Laboratory (NMML) and the Bureau of Ocean Energy Management (BOEM), ship-based visual...

  12. Release of Methane from Bering Sea Sediments During the Last Glacial Period

    Energy Technology Data Exchange (ETDEWEB)

    Mea Cook; Lloyd Keigwin

    2007-11-30

    Several lines of evidence suggest that during times of elevated methane flux the sulfate-methane transition zone (SMTZ) was positioned near the sediment-water interface. We studied two cores (from 700 m and 1457 m water depth) from the Umnak Plateau region. Anomalously low d13C and high d18O in benthic and planktonic foraminifera in these cores are the consequence of diagenetic overgrowths of authigenic carbonates. There are multiple layers of authigenic-carbonate-rich sediment in these cores, and the stable isotope compositions of the carbonates are consistent with those formed during anaerobic oxidation of methane (AOM). The carbonate-rich layers are associated with biomarkers produced by methane-oxidizing archaea, archaeol and glyceryl dibiphytanyl glyceryl tetraether (GDGT). The d13C of the archaeol and certain GDGTs are isotopically depleted. These carbonate- and AOM-biomarker-rich layers were emplaced in the SMTZ during episodes when there was a high flux of methane or methane-rich fluids upward in the sediment column. The sediment methane in the Umnak Plateau region appears to have been very dynamic during the glacial period, and interacted with the ocean-atmosphere system at millennial time scales. The upper-most carbonate-rich layers are in radiocarbon-dated sediment deposited during interstitials 2 and 3, 28-20 ka, and may be associated with the climate warming during this time.

  13. 50 CFR 600.1103 - Bering Sea and Aleutian Islands (BSAI) Crab species program.

    Science.gov (United States)

    2010-10-01

    ... to bid, NMFS will publish a notification in the Federal Register listing all persons who at the time... after issuing the notification in paragraph (m) of this section, NMFS will publish the invitation to bid...) Reduction payment tender and disbursement—(1) Fishing continues until tender. Each accepted bidder...

  14. Bering Sea Helicopter Surveys for Ice-Associated Seals (2007-08)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the spring of 2007 and 2008, researchers from the Alaska Fisheries Science Center conducted aerial surveys for ribbon, bearded, and spotted seals in the US...

  15. Detection of crude oil emulsions in the Bering Sea by the analysis of seawater color

    Science.gov (United States)

    Salyuk, Pavel A.; Stepochkin, Igor E.; Sokolova, Ekaterina B.; Kachur, Vasiliy A.; Prokuda, Natalya A.

    2015-11-01

    The paper presents the analysis of uncertainties between observed remote sensed reflectance spectra of seawater, with crude oil emulsions and oil dissolved fractions, and modeled remote sensed reflectance spectra of seawater without oil calculated from the fluorometric measurements of chlorophyll-a and dissolved organic matter concentrations carried out in the layer under oil pollution.

  16. 50 CFR Table 4 to Part 679 - Steller Sea Lion Protection Areas Pollock Fisheries Restrictions

    Science.gov (United States)

    2010-10-01

    ... 166°05.50 W 10 Unalaska I./Cape Sedanka 6 Gulf of Alaska 53°50.50 N 166°05.00 W 20 Old Man Rocks 6...°12.10 W 10 Amak I. And rocks 9 Bering Sea 55°24.20 N 163°09.60 W 55°26.15 N 163°08.50 W 10 Bird...

  17. Change in the Nd isotopic composition of the bottom water and detrital sediments on the Bering Slope over the last 500 kyrs with implications for the formation of the North Pacific Intermediate Water

    Science.gov (United States)

    Jang, K.; Huh, Y.; Han, Y.

    2015-12-01

    The Bering Sea is a potential location for the formation of the North Pacific Intermediate/Deep Water (NPIW/NPDW) and may play an important role in the global heat distribution. We reconstructed the neodymium isotopic ratio (ɛNd) of authigenic Fe-Mn oxide coatings and detrital sediments on the Bering Slope (IODP Expedition 323 site U1345; water depth 1008 m) over the last 500 kyrs. The ɛNd is a quasi-conservative water mass tracer. We compared three different leaching techniques to assure that authigenic signals are captured without contamination from terrigenous sources: (1) leaching (3 hours) with 0.02 M hydroxylamine hydrochloride (HH) in 25% buffered acetic acid after decarbonation; sediment/solution (v/v) > 10, (2) leaching (1 hour) with 0.02 M HH in 25% buffered acetic acid without decarbonation; sediment/solution ~ 1, and (3) leaching (1 hour) with 0.005 M HH in 1.5% buffered acetic acid-0.003 M Na-EDTA without decarbonation; sediment/solution > 40. The low Al concentrations and less radiogenic ɛNdvalues indicated that method (2) is the most appropriate leaching process. The average ɛNd of the authigenic fraction over the last 500 kyrs is -3.3 ± 0.9 (1σ, n=38), with large temporal fluctuations. The ɛNd of authigenic and detrital fractions are well correlated (r2 ~ 0.66), suggesting that the bottom water composition in the Bering Sea was governed by terrigenous inflow from surrounding areas. Radiogenic ɛNd peaks (up to -1.9) seem to be influenced by radiogenic water inflow from the the Kamchatka or Aluetian arcs. The high bulk density and low b* values imply higher terrigenous versus biological contribution and enhanced sea ice formation. Subsequent brine formation would have triggered sinking of radiogenic surface water, forming the NPIW. On the other hand, non-radiogenic ɛNd troughs (down to -5.3) are observed at times of low bulk density and high b* values. We presume higher biological productivity which is supported by the high opal content at

  18. Improving estimation of glacier volume change: a GLIMS case study of Bering Glacier System, Alaska

    OpenAIRE

    M. J. Beedle; Dyurgerov, M.; Tangborn, W.; Khalsa, S. J. S.; Helm, C.; Raup, B; Armstrong, R.; R. G. Barry

    2008-01-01

    The Global Land Ice Measurements from Space (GLIMS) project has developed tools and methods that can be employed by analysts to create accurate glacier outlines and resultant measures of glacier extent. To illustrate the importance of accurate glacier outlines and the effectiveness of GLIMS standards we have conducted a case study on Bering Glacier System (BGS), Alaska. BGS is a complex glacier system aggregated from multiple drainage basins, numerous individual ice streams, and many accumula...

  19. Walrus Bayesian State-space Model Output from the Bering Sea and Chukchi Sea, 2008-2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — State-space models offer researchers an objective approach to modeling complex animal location datasets, and state-space model behavior classifications are often...

  20. Structure and variability of the marine-bird community in the northeastern Chukchi Sea

    Science.gov (United States)

    Gall, Adrian E.; Day, Robert H.; Weingartner, Thomas J.

    2013-09-01

    We examined the seasonal and interannual variation in the marine-bird community and its relationship to physical oceanography in the northeastern Chukchi Sea in 2008-2010 as part of a multi-year, interdisciplinary study. We sampled 3 study areas, each ∼3000 km2, located in the offshore northeastern Chukchi Sea: Klondike, Burger, and Statoil. We quantified the marine habitat by measuring strength of stratification, depth of the mixed layer, and temperature and salinity in the upper mixed layer. The total density of seabirds was the highest in 2009, when warm (5-6 °C), moderately saline (31-31.5) Bering Sea Water (BSW) extended across Burger and Klondike at all depths. Bird density was generally higher in Klondike than in Burger in 2008 and 2009; densities did not differ significantly among study areas in 2010, when BSW covered all 3 study areas. The relative abundance of alcids in all study areas combined increased from 2008 to 2010. Klondike was numerically dominated by alcids and tubenoses in all years, whereas Burger was numerically dominated by larids and tubenoses in 2008 and by alcids in 2009 and 2010; Statoil also was numerically dominated by alcids in 2010. Least auklets, crested auklets, and northern fulmars were positively associated with strong stratification and high salinity (>31) in the upper mixed layer, characteristics that indicated the presence of BSW. Phalaropes were positively associated with salinity but negatively associated with stratification, suggesting that well-mixed water provides better foraging opportunities for these surface-feeding planktivores. The distribution and abundance of marine birds, particularly the planktivorous species, is influenced by advective processes that transport oceanic species of zooplankton from the Bering Sea to the Chukchi Sea. This transport apparently differed among years and resulted in a broader northeastward intrusion of Bering Sea Water and greater total abundance of planktivorous seabirds in the

  1. A tale of two seas: Reservoir age correction values (R, {delta}R) for the Sakhalin Island (Sea of Japan and Okhotsk Sea)

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmin, Y.V. [Pacific Institute of Geography, Far Eastern Branch of the Russian Academy of Sciences, Radio St. 7, Vladivostok 690041 (Russian Federation)]. E-mail: ykuzmin@tig.dvo.ru; Burr, G.S. [NSF-Arizona AMS Laboratory, University of Arizona, Tucson, AZ 85721-0081 (United States); Gorbunov, S.V. [Tymovsky Museum, Kharitonov St. 14, Tymovsky, Sakhalin Province 694400 (Russian Federation); Rakov, V.A. [Pacific Oceanographic Institute, Far Eastern Branch of the Russian Academy of Sciences, Baltiyskaya St. 43, Vladivostok 690041 (Russian Federation); Razjigaeva, N.G. [Pacific Institute of Geography, Far Eastern Branch of the Russian Academy of Sciences, Radio St. 7, Vladivostok 690041 (Russian Federation)

    2007-06-15

    This paper presents reservoir age determinations of pre-bomb marine mollusc shells from Sakhalin Island, Sea of Japan and Okhotsk Sea. The samples were collected from Japanese waste disposal sites created between 1905 and 1945. Radiocarbon analyses of the shells are used to establish marine reservoir age corrections for each site. The {delta}R value for the Sea of Japan, +95 {+-} 60 years, is consistent with previous data. The {delta}R value for the Okhotsk Sea is found to be +578 {+-} 50 years. The large difference in reservoir age between the two locations results from significantly different sources of surface water. The water source for the Sea of Japan is the Tsushima Current, a branch of the Kuroshio Current that originates in the equatorial Pacific and has a {delta}R value close to the mean ocean value. The primary water source for the Okhotsk Sea is the Oyashio Current, which transports water from the Bering Sea in the open Northern Pacific. This source is depleted with {sup 14}C, as compared with waters of the equatorial Pacific. The southern Kuriles (Zeleny and Yuri islands) reflect a mixture of Oyashio and Kuroshio waters, with a {delta}R value of +354 {+-} 23 years.

  2. A tale of two seas: Reservoir age correction values ( R, Δ R) for the Sakhalin Island (Sea of Japan and Okhotsk Sea)

    Science.gov (United States)

    Kuzmin, Y. V.; Burr, G. S.; Gorbunov, S. V.; Rakov, V. A.; Razjigaeva, N. G.

    2007-06-01

    This paper presents reservoir age determinations of pre-bomb marine mollusc shells from Sakhalin Island, Sea of Japan and Okhotsk Sea. The samples were collected from Japanese waste disposal sites created between 1905 and 1945. Radiocarbon analyses of the shells are used to establish marine reservoir age corrections for each site. The ΔR value for the Sea of Japan, +95 ± 60 years, is consistent with previous data. The ΔR value for the Okhotsk Sea is found to be +578 ± 50 years. The large difference in reservoir age between the two locations results from significantly different sources of surface water. The water source for the Sea of Japan is the Tsushima Current, a branch of the Kuroshio Current that originates in the equatorial Pacific and has a ΔR value close to the mean ocean value. The primary water source for the Okhotsk Sea is the Oyashio Current, which transports water from the Bering Sea in the open Northern Pacific. This source is depleted with 14C, as compared with waters of the equatorial Pacific. The southern Kuriles (Zeleny and Yuri islands) reflect a mixture of Oyashio and Kuroshio waters, with a ΔR value of +354 ± 23 years.

  3. High resolution Holocene sea ice records from Herald Canyon, Chukchi Sea

    Science.gov (United States)

    Pearce, Christof; Jakobsson, Martin; O'Regan, Matt; Rattray, Jayne; Barrientos, Natalia; Muchitiello, Francesco; Smittenburg, Rienk; Cronin, Tom; Coxall, Helen; Semiletov, Igor

    2016-04-01

    Arctic Ocean sea ice plays a critical role in the Earth's climate system because of the positive ice-albedo feedback mechanisms as well as its control on ocean-atmospheric heat exchange and potential influence on the thermohaline circulation. Key to improving our understanding of Arctic sea ice cover and its reaction to external forcing is the reconstruction of past variability through paleo-records such as marine sediment cores. Although the observed recent sea ice loss seems to be the strongest of the last millennia, it is still uncertain whether the shift from perennial to seasonal ice cover expected for the near future was unprecedented during the current interglacial. High resolution sea ice reconstructions from the Arctic Ocean are rare, and specifically records from the Russian Arctic are underrepresented. In this study, we present results from marine sediment cores from the Herald Canyon in the East Siberian Sea. The area is one of the major conduits of Pacific water entering the Arctic Ocean basin from the Bering Strait and is thus an ideal place to study past variability of the inflow of these nutrient rich waters. Radiocarbon dating of mollusks indicates very high sedimentation rates at the coring sites which allowed for analyses at centennial resolution up to decadal resolution in the late Holocene. Core samples were analyzed for the biomarker IP25, which is produced by diatoms living in sea ice and is used as a proxy of past seasonal sea ice concentrations. Preliminary results indicate the presence of seasonal sea ice during the entire Late Holocene and show a significant increase of sea ice concentrations during the last millennia.

  4. High resolution Holocene sea ice records from Herald Canyon, East Siberian Sea

    Science.gov (United States)

    Pearce, C.; Rattray, J.; Jakobsson, M.; Barrientos, N.; Muschitiello, F.; Smittenberg, R.; O'Regan, M.; Coxall, H.

    2015-12-01

    Arctic Ocean sea ice plays a critical role in the Earth's climate system because of the positive ice-albedo feedback mechanisms as well as its control on ocean-atmospheric heat exchange and potential influence on the thermohaline circulation. Key to improving our understanding of Arctic sea ice cover and its reaction to external forcing is the reconstruction of past variability through paleo-records such as marine sediment cores. Although the observed recent sea ice loss seems to be the strongest of the last millennia, it is still uncertain whether the shift from perennial to seasonal ice cover expected for the near future was unprecedented during the current interglacial. High resolution sea ice reconstructions from the Arctic Ocean are rare, and specifically records from the Russian Arctic are underrepresented. In this study, we present results from marine sediment cores from the Herald Canyon in the East Siberian Sea. The area is one of the major conduits of Pacific water entering the Arctic Ocean basin from the Bering Strait and is thus an ideal place to study past variability of the inflow of these nutrient rich waters. Radiocarbon dating of mollusks indicates very high sedimentation rates at the coring sites which allowed for analyses at centennial resolution up to decadal resolution in the late Holocene. Core samples were analyzed for the biomarker IP25, which is produced by diatoms living in sea ice and is used as a proxy of past seasonal sea ice concentrations. Preliminary results indicate the presence of seasonal sea ice during the entire Late Holocene and show a significant increase of sea ice concentrations during the last millennia.

  5. Stability of the Atlantic overturning circulation: competition between Bering Strait freshwater flux and Agulhas heat and salt sources

    NARCIS (Netherlands)

    Weijer, W.; Ruijter, W.P.M. de; Dijkstra, H.A.

    2002-01-01

    In this study we examine the role that is played by interocean fluxes of buoyancy in stabilizing the present-day overturning circulation of the Atlantic Ocean. A 2D model of the Atlantic overturning circulation is used, in which the interocean fluxes of heat and salt (via the Bering Strait, the Drak

  6. Surface depressions (Lacunas on Bering Glacier, Alaska: a product of downwasting through differential ablation

    Directory of Open Access Journals (Sweden)

    P. J. Fleisher

    2014-05-01

    Full Text Available Bering Glacier lacunas are steep-sided, flat-floored hollows ranging in size from 40 to 60 m wide, 80 to 120 m long, and 35 to 50 m in deep. They are confined within a band of clean ice (1.5 km wide, 5 km long paralleling the eastern margin of the Bering piedmont lobe. The 1993–1995 surge displaced the lacuna band several kilometers onto the foreland. Specifically significant is the formation of a new band of lacunas 5–6 years later in the same location occupied by the displaced band prior to the surge. Conditions essential to lacuna formation were initiated during the surge as overriding ice was thrust into position across the trend of a subglacial trough, leading to stagnation of ice within the trough. Stagnation combined with saturation at depth altered ice texture and density. Exposure of this ice through normal ablation led to areas of differential ablation and the formation of lacunas.

  7. Extent Layers for High-Resolution Orthorectified Imagery from 2003 for the Coastal Areas of Bering Land Bridge NP (BELA) and Cape Krusenstern NM (CAKR), Northwest Alaska

    Data.gov (United States)

    National Park Service, Department of the Interior — This vector shapefile is one of two layers that depict the extent of the 2003 digital orthophoto mosaic for the coastal and nearshore areas of Bering Land Bridge...

  8. Digitized Shorelines from Approximately 1950 1980, and 2003 for the Coastal Areas of Bering Land Bridge NP (BELA) and Cape Krusenstern NM (CAKR), Northwest Alaska

    Data.gov (United States)

    National Park Service, Department of the Interior — This file geodatabase contains all the feature classes relevant to the Digital Shorelines and Analysis for the Coastal Areas of Bering Land Bridge. These shoreline...

  9. Concentration and distribution of 17 organochlorine pesticides (OCPs) in seawater from the Japan Sea northward to the Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Seventeen classic organochlorine pesticides in surface seawater were studied in terms of their composition pattern as well as their distribution pattern in the areas covering the Japan Sea,Okhotsk Sea,Bering Sea,Chukchi Sea and Arctic Ocean.Their concentrations varied,but roughly two levels were seen with one ranging between 0.1 and 1 ng L-1 for most HCH isomers and the other lower than 0.1 ng L-1 for other chemicals.Of the 17 target compounds,HCHs were dominant with a total concentration percentage generally more than 50%,and a relatively high concentration percentage of heptachlor and aldrine was also observed at scattered stations.The historical long-term trend of several target chemicals in the five sea zones considered was discussed in comparison with previous reports.Inter-sea zone comparison was carried out for individual chemicals by comparing the concentration variation in all five sea zones.A higher variation in concentration was generally found in the northern sea zones,namely the Bering Sea,Chukchi Sea and Arctic Ocean,for most target compounds.The sum concentration of the 17 target chemicals displayed a general trend of increasing northward from the Japan Sea to the Okhotsk Sea to the Bering Sea to the Arctic Ocean.Different latitudinal trends were found forγ-HCH andγ-HCH,and the reason of this difference was discussed by considering their divergence of thermodynamic properties,which could contribute to a slightly different fractionation effect during their northward transport driven by atmospheric long range transport.The source of the HCHs was identified by analyzing theγ-HCH/γ-HCH ratio,which was less than 4 without exception,indicating a component characteristic featuring a mixture of technical HCHs and lindane.In addition,the vertical distribution ofγ-HCH,γ-HCH and their ratio at station B80 was discussed.Different patterns were found in the upper 300 m while in layers from 300 m downward to 3500 m the patterns were fairly comparable

  10. Hotspots in cold seas: The composition, distribution, and abundance of marine birds in the North American Arctic

    Science.gov (United States)

    Wong, Sarah N. P.; Gjerdrum, Carina; Morgan, Ken H.; Mallory, Mark L.

    2014-03-01

    The distribution and thickness of sea ice in the Arctic is changing rapidly, resulting in changes to Arctic marine ecosystems. Seabirds are widely regarded as indicators of marine environmental change, and understanding their distribution patterns can serve as a tool to monitor and elucidate biological changes in the Arctic seas. We examined the at-sea distribution of seabirds in the North American Arctic in July and August, 2007-2012, and marine areas of high density were identified based on bird densities for four foraging guilds. Short-tailed shearwaters (Puffinus tenuirostris) were the most abundant species observed. Northern fulmars (Fulmarus glacialis), thick-billed murres (Uria lomvia), and dovekies (Alle alle) were also sighted in large numbers. Few birds were sighted between Dolphin and Union Strait and King William Island. Areas of high density over multiple years were found throughout the entire western portion of the study area (Bering Sea, Bering Strait, and Chukchi Sea), Lancaster Sound, Baffin Bay, Davis Strait, and the low Arctic waters off Newfoundland. These waters are characterized by high primary productivity. This study is the first to document the marine distribution of seabirds across the entire North American Arctic within the same time period, providing a critical baseline for monitoring the distribution and abundance of Arctic seabirds in a changing Arctic seascape.

  11. The Propagation of a Surge Front on Bering Glacier, Alaska, 2001-2011

    Science.gov (United States)

    Turrin, James; Forster, Richard R.; Larsen, Chris; Sauber, Jeanne

    2013-01-01

    Bering Glacier, Alaska, USA, has a 20 year surge cycle, with its most recent surge reaching the terminus in 2011. To study this most recent activity a time series of ice velocity maps was produced by applying optical feature-tracking methods to Landsat-7 ETM+ imagery spanning 2001-11. The velocity maps show a yearly increase in ice surface velocity associated with the down-glacier movement of a surge front. In 2008/09 the maximum ice surface velocity was 1.5 plus or minus 0.017 kilometers per a in the mid-ablation zone, which decreased to 1.2 plus or minus 0.015 kilometers per a in 2009/10 in the lower ablation zone, and then increased to nearly 4.4 plus or minus 0.03 kilometers per a in summer 2011 when the surge front reached the glacier terminus. The surge front propagated down-glacier as a kinematic wave at an average rate of 4.4 plus or minus 2.0 kilometers per a between September 2002 and April 2009, then accelerated to 13.9 plus or minus 2.0 kilometers per a as it entered the piedmont lobe between April 2009 and September 2010. Thewave seems to have initiated near the confluence of Bering Glacier and Bagley Ice Valley as early as 2001, and the surge was triggered in 2008 further down-glacier in the mid-ablation zone after the wave passed an ice reservoir area.

  12. Random Seas

    DEFF Research Database (Denmark)

    Liu, Z.; Frigaard, Peter

    Sea waves are the most important phenomenon to be considering in the design of coastal and offshore structures.......Sea waves are the most important phenomenon to be considering in the design of coastal and offshore structures....

  13. 76 FR 66655 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod and Octopus in the Bering Sea...

    Science.gov (United States)

    2011-10-27

    ... established by the final 2011 and 2012 harvest specifications for groundfish in the BSAI (76 FR 11139, March 1, 2011). NMFS closed directed fishing for octopus on January 13, 2011 (76 FR 3044, January 19, 2011) and prohibited retention of octopus on September 1, 2011 (76 FR 55276, September 7, 2011). As of October 15,...

  14. 76 FR 17360 - Fisheries of the Exclusive Economic Zone Off Alaska; Octopus in the Bering Sea and Aleutian...

    Science.gov (United States)

    2011-03-29

    ... groundfish in the BSAI (76 FR 11139, March 1, 2011). The harvest specification for octopus included in the final 2011 and 2012 harvest specifications for groundfish in the BSAI (76 FR 11139, March 1, 2011) for... (76 FR 11139, March 1, 2011). In accordance with Sec. 679.20(a)(3) the Regional Administrator,...

  15. 76 FR 17034 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands; Final 2011...

    Science.gov (United States)

    2011-03-28

    ... Register on Tuesday, March 1, 2011 (76 FR 11139). Tables providing information on 2011 and 2012 Directed... incorrect information on Atka mackerel sideboard limits for the following areas and seasons: ``Eastern AI/BS'' for ``Jan 1-Jun 10''; ``Central AI'' for ``Jan 1-Jun 10''; and ``Central AI'' for ``Jan 1-Jun...

  16. AFSC/NMML: Marine Mammal Aerial Surveys in the Bering, Chukchi and Beaufort Seas . 1979-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bureau of Ocean Energy Management (BOEM), formerly the Minerals Management Service (MMS), and its precursor, the Bureau of Land Management, have funded aerial...

  17. AFSC/NMML: North Pacific right whale aerial surveys in the southeastern Bering Sea, 2008-2009.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of an inter-agency agreement between the National Marine Mammal Laboratory and the Bureau of Ocean Energy Management, aerial surveys of the North Aleutian...

  18. Bowhead (Balaena mysticetus) and beluga (Delphinapterus leucas) whales in the Bering, Chukchi and Beaufort Seas: Annual report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Reproductive activity in the bowhead whale was observed in early May near Pt. Barrow Alaska, indicating that this species may calf and breed during the northward...

  19. 78 FR 15677 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-03-12

    ... include cost, revenue, ownership, and employment data the North Pacific Fishery Management Council...: Notice of availability of fishery management plan amendment; request for comments. SUMMARY: NMFS announces that the North Pacific Fishery Management Council (Council) has submitted Amendment 42 to...

  20. 76 FR 40628 - Groundfish Fisheries of the EEZ Off Alaska; Pacific Halibut Fisheries; CDQ Program; Bering Sea...

    Science.gov (United States)

    2011-07-11

    ... removed just behind 08 the collar bone, and viscera removed Headed and gutted, tail removed. Head removed usually in 10 front of collar bone, and viscera and tail removed........ Heads. Heads only, regardless... 11 collar bone, viscera removed, and tail removed by cuts perpendicular to the spine, resulting in...

  1. 76 FR 44297 - Fisheries of the Exclusive Economic Zone Off Alaska; Allocating Bering Sea and Aleutian Islands...

    Science.gov (United States)

    2011-07-25

    ... each crab fishery to aid in price negotiations and arbitrations; (2) a formula arbitrator, who prepares... arbitrator, who reviews the positions of the parties during an arbitration proceeding and issues a binding...) clarifying the authority of the market analyst, formula arbitrator, and other parties involved in...

  2. AFSC/RACE/EcoFOCI: 2011 Fall Bering Sea Mooring Cruise DY11-04/3DY11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Our scheduled departure time was delayed due to a combination of weather and shipb??s equipment problems (navigation light, engine). The weather slowed our transit...

  3. 76 FR 13593 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-03-14

    ... directly regulated entities would be expected to benefit from this action relative to the status quo.... ACTION: Notice of availability of a proposed amendment to a fishery management plan; request for comments. SUMMARY: The North Pacific Fishery Management Council submitted Amendment 34 to the Fishery...

  4. Bottom Sediment Granulometric Data for the Continental Margins of the Bering, Chukchi, East Siberia, Laptev, and Beaufort Seas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are part of Roberts, Richard W., University of Washington, Department of Oceanography Special Report No. 70, Bottom Sediment Granulometric Data for the...

  5. 50 CFR 600.1105 - Longline catcher processor subsector of the Bering Sea and Aleutian Islands (BSAI) non-pollock...

    Science.gov (United States)

    2010-10-01

    ... Process is a Federal holiday, the date shall roll over to the next occurring business day. (2) Termination... and close the Selection Process, and there are no unresolved Protests or Arbitrations. Current Offer.... Selection Process means the process set forth in paragraph (d) of this section for selecting the...

  6. 75 FR 69401 - Fishing Capacity Reduction Program for the Longline Catcher Processor Subsector of the Bering Sea...

    Science.gov (United States)

    2010-11-12

    ... the implementing notice on August 11, 2006 (71 FR 46364), and published the final notice on September 29, 2006 (71 FR 57696). NMFS allocated the $35,000,000 reduction loan to the reduction fishery and is repayable by fees from the fishery. NMFS published in the Federal Register on September 24, 2007 (72...

  7. 50 CFR 600.1106 - Longline catcher processor subsector Bering Sea and Aleutian Islands (BSAI) non-pollock...

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Longline catcher processor subsector... Fishery or Program Fishing Capacity Reduction Regulations § 600.1106 Longline catcher processor subsector... longline catcher processor subsector of the BSAI non-pollock groundfish fishery that § 679.2 of...

  8. 78 FR 10135 - Fishing Capacity Reduction Program for the Longline Catcher Processor Subsector of the Bering Sea...

    Science.gov (United States)

    2013-02-13

    ... the implementing notice on August 11, 2006 (71 FR 46364), and published the final notice on September 29, 2006 (71 FR 57696). NMFS allocated the $35,000,000 reduction loan (A loan) to the reduction... the Federal Register (72 FR 54219), the final rule to implement the industry fee system for...

  9. 76 FR 74048 - Fishing Capacity Reduction Program for the Longline Catcher Processor Subsector of the Bering Sea...

    Science.gov (United States)

    2011-11-30

    ... the implementing notice on August 11, 2006 (71 FR 46364), and published the final notice on September 29, 2006 (71 FR 57696). NMFS allocated the $35,000,000 reduction loan to the reduction fishery and is repayable by fees from the fishery. NMFS published in the Federal Register on September 24, 2007 (72...

  10. 75 FR 38454 - Fisheries of the Exclusive Economic Zone Off Alaska; Skates Management in the Bering Sea and...

    Science.gov (United States)

    2010-07-02

    ... accountability measures (AMs) and conform to the National Standard 1 (NS1) guidelines (74 FR 3178, January 16...'' category in response to a rapidly developing directed fishery (69 FR 26313, May 12, 2004). A retrospective... reinforce existing requirements to prevent overfishing and rebuild fisheries. NMFS revised the...

  11. 76 FR 35781 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-06-20

    ... Availability of this amendment in the Federal Register on February 1, 2011 (76 FR 5556), with comments invited through April 4, 2011. NMFS published the proposed rule for this action on February 25, 2011 (76 FR 8700..., 2010, 75 FR 7205). NMFS extended the emergency action on August 17, 2010 (75 FR 50716). The...

  12. 76 FR 35772 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-06-20

    ... qualifying years and are fully described in the preamble to the proposed rule for this action (76 FR 17088... FR 13593), with a public comment period that closed on May 13, 2011. NMFS published the proposed rule to implement Amendment 34 on March 28, 2011 (76 FR 17088), and the public comment period closed...

  13. 78 FR 36122 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-06-17

    ... the FMP. NMFS published a notice of availability (NOA) for Amendment 42 on March 12, 2013 (78 FR 15677... implement Amendment 42 on March 21, 2013 (78 FR 17341). The comment period on the proposed rule ended on... in detail in the proposed rule to implement Amendment 42 (78 FR 17341, March 21, 2013) and...

  14. 78 FR 6279 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-01-30

    ... 18 and 19 to the FMP, on March 2, 2005 (70 FR 10174). Regulations implementing the FMP and all... the final rule (76 FR 35781, June 20, 2011). Because the conditions that have impeded deliveries... use caps, please see the proposed rule for the CR Program (69 FR 63200; October 29, 2004)....

  15. 75 FR 50716 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2010-08-17

    ... August 17, 2010 (75 FR 7205). NMFS invited public comments until March 22, 2010. NMFS received no public... (75 FR 7205, February 18, 2010) provides additional background information. Section 305(c)(3)(B) of... public interest. In the initial emergency rule published on February 18, 2010 (75 FR 7205),...

  16. 76 FR 68358 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-11-04

    ... system is found in the preamble to the proposed rule (October 24, 2004; 69 FR 63200) and final rule (March 2, 2005; 70 FR 10174) that implemented the CR Program, as well as in the final EIS prepared for... NMFS published the notice of availability for Amendment 30 on July 25, 2011 (76 FR 44297), with...

  17. 78 FR 28523 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-05-15

    ... published a notice of availability for Amendment 41 on December 13, 2012 (77 FR 74161). The comment period... on January 30, 2013 (78 FR 6279). The comment period on the proposed rule ended on March 1, 2013... provided in the notice of availability for Amendment 41 (December 13, 2012, 77 FR 74161) and the...

  18. 76 FR 8700 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-02-15

    ... on March 2, 2005 (70 FR 10174). Regulations implementing the FMP and all amendments to the Program...-designated IPQ for the WAG fishery from the West regional designation until August 17, 2010 (75 FR 7205... these shares be used in the West region. NMFS extended the emergency action on August 17, 2010 (75...

  19. 76 FR 25295 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands King and...

    Science.gov (United States)

    2011-05-04

    ... each crab stock. This action is necessary to account for uncertainty in the overfishing limit and prevent overfishing. If approved, Amendment 39 would modify the snow crab rebuilding plan to define the... overfishing, achievement of optimum yield, and establishment of annual catch limits. The following is...

  20. AFSC/NMML with NPRB: Location-only satellite telemetry data for North Pacific Right Whales, Bering Sea, 2008 - 2009

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains ARGOS location data (latitude and longitude in decimal format) and associated time (date and time) and location quality (as defined by Argos...

  1. Northern fur seal foraging behavior and prey fields in the Bering Sea, Alaska during July-October 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data were used by Kuhn et al. (2015) to investigate how conclusions about predator-prey relationships change with increasing temporal disparity between...

  2. The Structure of Genetic Diversity in Eelgrass (Zostera marina L.) along the North Pacific and Bering Sea Coasts of Alaska

    Science.gov (United States)

    Talbot, Sandra; Sage, Kevin; Rearick, Jolene; Fowler, Megan C.; Muñiz-Salazar, Raquel; Baibak, Bethany; Wyllie-Echeverria, Sandy; Cabello-Pasini, Alehandro; Ward, David H.

    2016-01-01

    Eelgrass (Zostera marina) populations occupying coastal waters of Alaska are separated by a peninsula and island archipelago into two Large Marine Ecosystems (LMEs). From populations in both LMEs, we characterize genetic diversity, population structure, and polarity in gene flow using nuclear microsatellite fragment and chloroplast and nuclear sequence data. An inverse relationship between genetic diversity and latitude was observed (heterozygosity: R2 = 0.738, P genetic partitioning across most sampling sites (θ = 0.302, P Genetic data failed to support recent proposals that multiple Zostera species (i.e. Z. japonica and Z. angustifolia) are codistributed with Z. marina in Alaska. Comparative analyses also failed to support the hypothesis that eelgrass populations in the North Atlantic derived from eelgrass retained in northeastern Pacific Last Glacial Maximum refugia. These data suggest northeastern Pacific populations are derived from populations expanding northward from temperate populations following climate amelioration at the terminus of the last Pleistocene glaciation.

  3. AFSC/NMML Location-only satellite telemetry data for North Pacific Humpback Whales in the Bering Sea, 2007 - 2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains ARGOS location data (latitude and longitude in decimal format) and associated time (date and time) and location quality (as defined by Argos...

  4. Mapping human interaction with the Bering Sea ecosystem: Comparing seasonal use areas, lifetime use areas, and "calorie-sheds"

    Science.gov (United States)

    Huntington, Henry P.; Ortiz, Ivonne; Noongwook, George; Fidel, Maryann; Childers, Dorothy; Morse, Muriel; Beaty, Julia; Alessa, Lilian; Kliskey, Andrew

    2013-10-01

    Alaska Native coastal communities interact with the marine environment in many ways, especially through the harvest of fish, marine mammals, and seabirds. The spatial characteristics of this interaction are often depicted in terms of subsistence use areas: the places where harvests and associated travel occur. Another way to consider the interaction is to examine the areas where harvested species range during their lifecycle or annual migratory path. In this paper, we compare seasonal subsistence use areas, lifetime subsistence use areas, and "calorie-sheds," or the area over which harvested species range. Each perspective offers useful information concerning not only the nature of human-environment interactions but also the scope for potential conflict with other human activity and the means by which such conflicts could be reduced, avoided, or otherwise addressed. Seasonal subsistence use areas can be used to manage short-term activities, such as seasonal vessel traffic during community re-supply. Lifetime subsistence use areas indicate the area required to allow hunters and fishers the flexibility to adjust to interannual variability and perhaps to adapt to a changing environment. Calorie-sheds indicate the areas about which a community may be concerned due to potential impacts on the species they harvest.

  5. MGL111 Chirp - US Extended Continental Shelf Project: Bering Sea CHIRP high-resolution Seismic Profile data.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Knudsen 2620 acquired sub-bottom profiles continuously throughout the cruise. The Knudsen was operated in 3.5 kHz Chirp mode, emitting a 1.5 kHz to 5 kHz (3 kHz...

  6. 76 FR 49417 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2011-08-10

    ... comprised of vessel owners with a wide range of vessels. Their cooperative contracts govern the specific... industry time to structure their cooperative contracts to incorporate ``all-in'' provisions necessary to... Program to modify the criteria for forming and participating in a harvesting cooperative. This action...

  7. Operational Data Report C&GS DR-8, Seismic Reflection Profiles Northern Bering Sea (NODC Accession 7000753)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A series of seismic reflection profiles were taken aboard the USC&GSS SURVEYOR during the summer of 1969 as part of a general continental shelf survey in the...

  8. 77 FR 20339 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2012-04-04

    ... provide a competitive advantage to larger replacement vessels. Under Amendment 97, a vessel owner could... Administrator, Sustainable Fisheries Division, Alaska Region, NMFS, Attn: Ellen Sebastian. You may submit... Glenn Merrill, Assistant Regional Administrator, Sustainable Fisheries Division, Alaska Region...

  9. 77 FR 62482 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2012-10-15

    ... information in lieu of pooled information, increased use of systematic sampling over simple random and... program in April 2006 (71 FR 17362), and the GRS program became effective in 2008. As originally... is described in the preamble to the final rule for the GRS program (71 FR 17362, April 6, 2006)...

  10. Continuous Measurements of Ice Motion and Associated Seismicity at Bering Glacier, Alaska.

    Science.gov (United States)

    Larsen, C. F.; Truffer, M.; Leblanc, L.; O'Neel, S.; West, M.; None, N.

    2007-12-01

    In April 2007, we established an array of GPS and seismic stations on the Bering Glacier, Alaska, to investigate the relationship between glacier motion and glacier-generated seismicity. Bering Glacier is North America's largest mountain glacier and has an area of more than 5000 km2. Dual-frequency GPS data were recorded continuously at 15 second intervals at five stations on the glacier from April to September. Four of the GPS glacier stations were established in a strain diamond located roughly halfway between the equilibrium line and the terminus, at a distance of 40 km from a GPS base station located near the terminus. These four GPS glacier stations were co-located with seismometers, which, together with a fifth seismometer located at center of the strain diamond, form a cross pattern seismic array with a 4-km aperture. The fifth GPS station is located 20 km up glacier from the strain diamond and seismic array, at a point where the upper icefield feeds into a narrow gate to the lower glacier. GPS antennas were fixed to tripods constructed of steel poles drilled 5-7 m deep into the surface of the glacier. This provides a stable reference relative to the glacier surface, which is subject to several meters of annual ablation at the elevation of the strain diamond. The GPS data have been processed using the GAMIT kinematic utility Track. The motion recorded at all sites is rapid (3+ m/day) but smooth and steady down to the temporal resolution of the data. Specifically, we find no evidence for sudden motion events in the timeseries, but rather find only small perturbations superimposed on slowly varying velocities. The seismic records from short period (L-22) and broadband (6TD) instruments reveal frequent icequakes including both emergent low frequency events and impulsive high frequency events. Many of the events recorded show strong time domain correlations across the array. We will construct a timeseries of seismicty using an automatic icequake detector

  11. Input of Terrestrial Palynomorphs since the Last Deglaciation from Sediments of the Chukchi Sea Shelf, Western Arctic Ocean

    Science.gov (United States)

    Delusina, I.; Kim, S. Y.; Nam, S. I.; Woo, K. S.

    2014-12-01

    We report the palynology of marine sediment core ARA02B/01A-GC from the Western margin of the shallow shelf of the Chukchi Sea in the Arctic, a site which was synchronously influenced by climatic changes during the last deglaciation with those in the Bering Strait. The core contains a rich concentration of continental palynomorphs, even though the coring location is quite a distance from land. The catchment area for the observed palynomorphs includes the territories of both North America (Alaska and North Canada) and Northern Siberia (Chukotka peninsula and Northern East-Siberian coast). Based on this fact, we can reconstruct a common paleoenvironmental history for this location and the Bering Strait during the postglacial interval. We hypothesize that palynomorphs were carried to the sea during low sea-ice coverage intervals by large rivers (Yukon, Mackenzie and Siberian rivers) and were then transferred by oceanic currents. During intervals of extensive sea-ice coverage the source of the palynomorphs was predominantly eroded shelf sediments. The percentage ratio of tree-herb pollen and spores in the palynomorph assemblages shows that favorable conditions for an increase in forest vegetation took place between ~8 and 4 kyr BP, which coincides with maximum freshwater input to the sea. During a climatic optimum at ~5 kyr BP, as inferred from the total dominance of tree and herb pollen, the Chukchi Sea was apparently warmer than today. This represents the maximum ice-free period for the sea. The low sea-ice interval ended ~3 kyr BP, as suggested by a sharp drop in tree pollen, a reduction in fresh water input, and a drop in the concentration of the algae Pediastrum. Our data correlate well with data from marine core HLY0501-5 from the Bering Strait (Polyak et al., 2009) for the interval of 10-8 kyr BP, but shows a divergence since ~4 kyr BP, which may correspond to the beginning of the differentiation of North American and East-Siberian ecosystem zones.

  12. Improving Sea Ice Prediction in the NCEP Climate Forecast System Model

    Science.gov (United States)

    Collow, T. W.; Wang, W.; Kumar, A.

    2015-12-01

    Skillful prediction of Arctic sea ice is important for the wide variety of interests focused in that region. However, the current operational system used by the NOAA Climate Prediction Center does not adequately predict the seasonal climatology of sea ice extent and maintains too high sea ice coverage across the Arctic. It is thought that the primary reasoning for this lies in the initialization of sea ice thickness. Experiments are carried out using the Climate Forecast System (CFSv2) model with an improved sea ice thickness initialization from the Pan-Arctic Ice Ocean Analysis and Assimilation System (PIOMAS) rather than the default Climate Forecast System Reanalysis (CFSR) sea ice thickness data. All other variables are initialized from CFSR. In addition, physics parameterizations are adjusted to better simulate real world conditions. Here we focus on hindcasts initialized from 2005-2014. Although the seasonal cycle of sea ice is generally better captured in runs that use PIOMAS sea ice thickness initialization, local sea ice freeze in early winter in the Bering Strait and Chukchi Sea is delayed when both sea ice thickness configurations are used. In addition ice freeze in the North Atlantic is more pronounced than in the observations. This shows that simply changing initial sea ice thickness is not enough to improve forecasts for all locations. Modeled atmospheric and oceanic parameters are investigated including the radiation budget, land surface temperature advection, and sub-surface oceanic heat flow to diagnose possible reasons for the modeling deficiencies, and further modifications to the model will be discussed.

  13. 楚科奇海和白令海毛颚类的分布%DISTRIBUTION OF CHAETOGNATHA IN CHUKCHI SEA AND BERING SEA

    Institute of Scientific and Technical Information of China (English)

    戴燕玉

    2002-01-01

    根据1997年7─8月我国首次北极科学考察期间,分别在楚科奇海和白令海进行海洋综合调查的资料,分析了这两区毛颚类种类组成和生态类型的特征、丰度的水平分布、层状分布和昼夜垂直分布.同时还就其数量分布与某些环境因子的相关性进行初步探讨.研究表明:(1)两区共记录毛颚类7种,可分为3个类群,在数量上,白令海的个体数明显高于楚科奇海;其平面分布的状况主要由优势种所左右,并且都呈现出南高北低的分布格局.(2)在楚科奇海,毛颚类的层状分布以50─200m层数量较高,500─800 m层最低.白令海毛颚类的昼夜垂直分布的趋势是,白天总个体数最高比值均出现在200─500m层,而晚上─凌晨则密集于100m以浅水域,尤以0─50m层数量最高,表现出白天下降夜晚上升的分布规律.

  14. Assessment of Competition between Fisheries and Steller Sea Lions in Alaska Based on Estimated Prey Biomass, Fisheries Removals and Predator Foraging Behaviour.

    Science.gov (United States)

    Hui, Tabitha C Y; Gryba, Rowenna; Gregr, Edward J; Trites, Andrew W

    2015-01-01

    A leading hypothesis to explain the dramatic decline of Steller sea lions (Eumetopias jubatus) in western Alaska during the latter part of the 20th century is a change in prey availability due to commercial fisheries. We tested this hypothesis by exploring the relationships between sea lion population trends, fishery catches, and the prey biomass accessible to sea lions around 33 rookeries between 2000 and 2008. We focused on three commercially important species that have dominated the sea lion diet during the population decline: walleye pollock, Pacific cod and Atka mackerel. We estimated available prey biomass by removing fishery catches from predicted prey biomass distributions in the Aleutian Islands, Bering Sea and Gulf of Alaska; and modelled the likelihood of sea lions foraging at different distances from rookeries (accessibility) using satellite telemetry locations of tracked animals. We combined this accessibility model with the prey distributions to estimate the prey biomass accessible to sea lions by rookery. For each rookery, we compared sea lion population change to accessible prey biomass. Of 304 comparisons, we found 3 statistically significant relationships, all suggesting that sea lion populations increased with increasing prey accessibility. Given that the majority of comparisons showed no significant effect, it seems unlikely that the availability of pollock, cod or Atka mackerel was limiting sea lion populations in the 2000s.

  15. Relating Regional Arctic Sea Ice and climate extremes over Europe

    Science.gov (United States)

    Ionita-Scholz, Monica; Grosfeld, Klaus; Lohmann, Gerrit; Scholz, Patrick

    2016-04-01

    The potential increase of temperature extremes under climate change is a major threat to society, as temperature extremes have a deep impact on environment, hydrology, agriculture, society and economy. Hence, the analysis of the mechanisms underlying their occurrence, including their relationships with the large-scale atmospheric circulation and sea ice concentration, is of major importance. At the same time, the decline in Arctic sea ice cover during the last 30 years has been widely documented and it is clear that this change is having profound impacts at regional as well as planetary scale. As such, this study aims to investigate the relation between the autumn regional sea ice concentration variability and cold winters in Europe, as identified by the numbers of cold nights (TN10p), cold days (TX10p), ice days (ID) and consecutive frost days (CFD). We analyze the relationship between Arctic sea ice variation in autumn (September-October-November) averaged over eight different Arctic regions (Barents/Kara Seas, Beaufort Sea, Chukchi/Bering Seas, Central Arctic, Greenland Sea, Labrador Sea/Baffin Bay, Laptev/East Siberian Seas and Northern Hemisphere) and variations in atmospheric circulation and climate extreme indices in the following winter season over Europe using composite map analysis. Based on the composite map analysis it is shown that the response of the winter extreme temperatures over Europe is highly correlated/connected to changes in Arctic sea ice variability. However, this signal is not symmetrical for the case of high and low sea ice years. Moreover, the response of temperatures extreme over Europe to sea ice variability over the different Arctic regions differs substantially. The regions which have the strongest impact on the extreme winter temperature over Europe are: Barents/Kara Seas, Beaufort Sea, Central Arctic and the Northern Hemisphere. For the years of high sea ice concentration in the Barents/Kara Seas there is a reduction in the number

  16. Sea level trends in South East Asian Seas (SEAS

    Directory of Open Access Journals (Sweden)

    M. W. Strassburg

    2014-10-01

    Full Text Available Southeast Asian Seas (SEAS span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian Oceans. The SEAS regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost two decades. Initial comparisons of global sea level reconstructions find that 17 year sea level trends over the past 60 years exhibit good agreement in areas and at times of strong signal to noise associated decadal variability forced by low frequency variations in Pacific trade winds. The SEAS region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer time scales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO to sea level trends in the past twenty years, the rate of sea level rise is greatly reduced in the SEAS region. As a result of the influence of the PDO, the SEAS regional sea level trends during 2010s and 2020s are likely to be less than the global mean sea level (GMSL trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the SEAS will continue to be affected by GMSL rise occurring now and in the future.

  17. Bowhead whale body condition and links to summer sea ice and upwelling in the Beaufort Sea

    Science.gov (United States)

    George, John C.; Druckenmiller, Matthew L.; Laidre, Kristin L.; Suydam, Robert; Person, Brian

    2015-08-01

    We examined the response of bowhead whale (Balaena mysticetus) body condition to summer sea ice conditions and upwelling-favorable winds. We used a long-term dataset collected from whales of the Bering-Chukchi-Beaufort Seas (BCB) stock to estimate various body condition indices (BCI's) for individual whales that were harvested by Alaskan Eskimos. A series of offshore regions frequented by bowhead whales in summer were delineated and used to quantify interannual summertime environmental conditions including: (a) mean open water fraction, (b) duration of melt season, (c) date of continuous freeze-up, and (d) mean upwelling-favorable wind stress. Body condition was analyzed relative to these metrics for both the preceding summer feeding season and the previous three seasons combined. Our analysis indicates a significant increase in the long-term trend in an axillary girth-based body condition index (BCIG) over the study period (1989-2011). The increase in BCIG is likely associated with the trend in overall reduction of sea ice, including increased duration of open water, changes in upwelling potential (wind stress), and possibly higher primary production in the Pacific Arctic marine ecosystem favoring water-column invertebrates. We found strong significant positive correlations between BCIG and late summer open water fraction in the Beaufort Sea and smaller nearshore areas off the Mackenzie Delta and west of Banks Island. Additionally, BCIG was positively and significantly correlated with duration of melt season, later date of freeze-up in the Beaufort Sea, and upwelling-favorable winds on the Mackenzie shelf and west of Banks Island. A strong seasonal difference in BCI's was noted for subadult bowheads, presumably associated with summer feeding; however, yearlings were found to drop in BCI over at least the first summer after weaning. Our results indicate an overall increase in bowhead whale body condition and a positive correlation with summer sea ice loss over the

  18. Temperature, salinity, velocity including ADCP ice tracking, and bottom pressure collected from moored buoys in Bering Strait from 2011-07-14 to 2013-07-05 (NCEI Accession 0138173)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data from moorings deployed in the US waters of the Bering Strait from summer 2011 to summer 2013 (with mooring servicing in summer 2012). For...

  19. Temperature, salinity, velocity including ADCP ice tracking, and bottom pressure collected by Bering Strait Moorings A2W, A2, A4W, A4, A3 from 2010-08-03 to 2011-07-14 (NCEI Accession 0138583)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data from US moorings deployed in the Bering Strait from summer 2010 to summer 2011. Moorings were also deployed for this period in Russian...

  20. Temperature, salinity, oxygen and fluorescence profiles collected by CTD from the Norseman II in Bering Strait from 2013-07-04 to 2013-07-10 (NCEI Accession 0136939)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archive is of data from 150 CTD casts taken during the 2013 Norseman II cruise to the Bering Strait. For positions, see file headers or the cruise report...

  1. Oceanographic station data from bottle casts from the BERING STRAIT from Ocean Weather Station V (OWS-V) in the North Pacific Ocean 05 July 1969 to 25 July 1969 (NODC Accession 6900858)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic station data were collected from the BERING STRAIT within a 1-mile radius of Ocean Weather Station V (3400N 16400E) and in transit. Data were...

  2. Temperature, salinity, velocity including ADCP ice tracking, and bottom pressure collected by Bering Strait Moorings A1W, A1, A1E from 2010-08-03 to 2012-08-25 (NCEI Accession 0138174)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data from US moorings deployed in the Russian Channel of the Bering Strait from summer 2010 to summer 2012. The deployments were designed to...

  3. Temperature profile data from Mechanical Bathythermograph (MBT) casts from the BERING STRAIT, STRANGER, and other platforms in the North Pacific, Coastal Equatorial Pacific, and other locations from 1945 to 1968 (NODC Accession 0000507)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profiles were collected from Mechanical Bathythermograph (MBT) casts from the BERING STRAIT, STRANGER, and other platforms. Data were collected from 02...

  4. Oceanographic station data from bottle casts from the BERING STRAIT from Ocean Weather Station V (OWS-V) in the North Pacific Ocean 21 February 1970 to 12 March 1970 (NODC Accession 7000733)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic station data were collected from the BERING STRAIT within a 1-mile radius of Ocean Weather Station V (3400N 16400E) and in transit. Data were...

  5. Sea Ice

    Science.gov (United States)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  6. 白令海峡水团来源的镭同位素示踪%Water masses in the Bering Strait revealed by radium isotopes

    Institute of Scientific and Technical Information of China (English)

    陈敏; 李艳平; 邱雨生; 杨俊鸿

    2011-01-01

    Radium isotopes in the water column along 64.3°N in the Bering Strait were determined to reveal the northward flow of the Pacific water.The specific activities of 226 Ra and 228Ra, and the 228 Ra/226 Ra)A.R.show a longitudinal variation in the Bering Strait, depicting the pathways of Pacific inflow.Based on the distributions of temperature, salinity and radium isotopes in the Bering Strait, three water masses were identified: the Anadyr Water in the western channel, the Alaskan Coastal Water in the eastern channel, and the Bering Shelf Water in the central strait.A subseasonal variation of radium isotopes in the Bering Strait was observed.The specific activities of 226 Ra and 228 Ra, and 228 Ra/226 Ra) A.R in September are higher than those observed in July, indicating water in the western Bering Strait is influenced by the southward flow of the Siberia Coastal Current in September.%对白令海峡64.3°N纬向断面镭同位素的研究表明,水体中226Ra比活度、228Ra比活度和228Ra/226Ra)A.R.存在明显的纬向变化,反映出太平洋与北冰洋水体交换的多种路径.根据温度、盐度和镭同位素的水平与垂直分布,太平洋水进入北冰洋的路径可能主要有3支,分别为白令海峡西侧的阿拉德水、白令海峡东侧的阿拉斯加沿岸水和中部的白令海陆架水.2003年7月和9月对该断面西侧站位进行的复测显示,水体中的226Ra比活度、228Ra比活度和228Ra/226Ra)A.R.发生了明显变化,9月份测值均高于7月份测值,说明白令海峡西部水体在9月份可能受到西伯利亚沿岸流南向混合的影响.

  7. Automated Lagrangian Water-Quality Assessment System (ALWAS) Measurements of North Slope Lakes and the Bering Glacier, Alaska

    Science.gov (United States)

    Shuchman, R.; Meadows, G.; Liversedge, L.; Hatt, C.; Vansumeren, H.; Payne, J.

    2007-12-01

    ALWAS is an inexpensive, free-floating, sail-powered or jet-driven water quality measuring and watershed evaluation buoy. It is capable of measuring data points with multiple parameters (depth, temperature, conductivity, salinity, total dissolved solids, dissolved oxygen, pH, oxidation reduction potential, turbidity, chlorophyll-a, blue-green algae, nitrate, ammonium, chloride, latitude/longitude, date, time, speed, and barometric pressure) as rapidly as every 40 seconds. Data is transmitted for real-time viewing and is stored for future retrieval and analysis. The collected data are easily downloaded into geographic databases (ESRI shapefile) and spreadsheet formats. ALWAS uses state-of-the-art sensors to measure water quality parameters and GPS data. Field demonstrations of the ALWAS technology from the Bering Glacier and the North Slope of Alaska will be presented. The ALWAS buoy will also be described as well as ALWAS data sharing, web-based mapping, and decision support tools.

  8. Modeling seasonal variations of ocean and sea ice circulation in the Beaufort and Chukchi Seas: A model-data fusion study

    Institute of Scientific and Technical Information of China (English)

    WANG Jia; Kohei Mizobata; HU Haoguo; JIN Mei-bing; ZHANG Sheng; Walter Johnson; Koji Shimada; Moto Ikeda

    2008-01-01

    A 3.8-km Coupled Ice-Ocean Model (CIOM) was implemented to successfully reproduce many observed phenomena in the Beaufort and Chukchi seas, including the Bering-inflow-originated coastal current that splits into three branches:Alaska Coastal Water (ACW) , Central Channel, and Herald Valley branches. Other modeled phenomena include the Beaufort Slope Current (BSC) , the Beautort Gyre,the East Siberian Current (ESC), mesoscale eddies, seasonal landfast ice, sea ice ridging, shear, and deformation. Many of these downscaling processes can only be captured by using a high-resolution C1OM, nested in a global climate model. The seasonal cycles for sea ice concentration, thickness, velocity, and other variables are well reproduced with solid validation by satellite measurements. The seasonal cycles for upper ocean dynamics and thermodynamics are also well reproduced, which inelude the formation of the cold saline layer due to the injection of salt during sea ice formation, the BSC, and the subsurface upwelling in winter that brings up warm, even more saline Atlantic Water along the shelfbreak and shelf along the Beaufort coast.

  9. Arctic sea ice melt onset from passive microwave satellite data: 1979–2012

    Directory of Open Access Journals (Sweden)

    A. C. Bliss

    2014-06-01

    Full Text Available An updated version of the Snow Melt Onset Over Arctic Sea Ice from SMMR and SSM/I-SSMIS Brightness Temperatures is now available. The data record has been re-processed and extended to cover the years 1979–2012. From this data set, a statistical summary of melt onset (MO dates on Arctic sea ice is presented. The mean MO date for the Arctic Region is 13 May (132.5 DOY with a standard deviation of ±7.3 days. Regionally, mean MO dates vary from 15 March (73.2 DOY in the St. Lawrence Gulf to 10 June (160.9 DOY in the Central Arctic. Statistically significant decadal trends indicate that MO is occurring 6.6 days decade−1 earlier in the year for the Arctic Region. Regionally, MO trends are as great as −11.8 days decade−1 in the East Siberian Sea. The Bering Sea is an outlier and MO is occurring 3.1 days decade−1 later in the year.

  10. Mammals of the Sea.

    Science.gov (United States)

    Naturescope, 1986

    1986-01-01

    Presents information on sea mammals, including definitions and characteristics of cetaceans, pinnipeds, and sirenians. Contains descriptions of the teaching activities "Whale Music,""Draw A Whale to Scale,""Adopt a Sea Mammal," and "Sea Mammal Sleuths." (TW)

  11. The role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jinlun; MI ke Steele; Rebecca Woodgate

    2008-01-01

    A model study is conducted to examine the role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007. The model generally agrees with the observations in showing considerable seasonal and intcrannual variability of the Pacific water inflow at Bering Strait in response to changes in atmospheric circulation.During summer 2007 anomalously strong southerly winds over the Pacific sector of the Arctic Ocean strengthen the ocean circulation and bring more Pacific water into the Arctic than the recent (2000-2006) average. The simulated summer (3 months )2007 mean Pacific water inflow at Bering Strait is 1.2 Sv, which is the highest in the past three decades of the simulation and is 20% higher than the recent average. Particularly, the Pacific water inflow in September 2007 is about 0.5 Sv or 50% above the 2000-2006 average. The strengthened warm Pacific water inflow carries an additional 1.0 × 1020 Joules of heat into the Arctic, enough to melt an additional 0. 5 m of ice over the whole Chukchi Sea. In the model the extra summer oceanic heat brought in by the Pacific water mainly stays in the Chukchi and Beaufort region, contributing to the wanning of surface waters in that region. The heat is in constant contact with the ice cover in the region in July through September. Thus the Pacific water plays a role in ice melting in the Chukchi and Beaufort region all summer long in 2007, likely contributing to up to 0.5 m per month additional ice melting in some area of that region.

  12. Alaska Phocid Argos Telemetry Archive (2004-2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Polar Ecosystems Program conducts research and monitoring on phocid seals in the East Bering Sea, West Bering Sea, Gulf of Alaska, Beaufort Sea, and Chukchi Sea...

  13. Winter climate change and sea ice-atmosphere interaction at high northern latitudes in ERA40 dataset

    Institute of Scientific and Technical Information of China (English)

    Liu Xiying

    2006-01-01

    Based on the reanalysis dataset ERA40 of European Center of Medium Range Weather Forcast (ECMWF), winter climate change and characteristics of sea ice-atmosphere interaction at high northern latitudes for recent several tens of years are analyzed. Superposed upon the background of global warming, the amplitude of temperature increase in winter at high northern latitudes is bigger and it exhibits different features in different regions. From the end of 1970 s, the Greenland Sea, the Barents Sea and most part of Euro-Asian continent and North American continent are getting warmer, whereas the Labrador Sea, the Greenland and the area around the Bering Strait are getting colder. Meanwhile, the sea level pressure in the central part of the northern polar region and the place where the climatic Icelandic low exist decreases, but in places farther southward it increases. Since the 1970 s, the sensible heat flux and latent heat flux sent to the atmosphere from the Greenland Sea and the Barents Sea has increased, this is mainly due to the reduction of sea ice concentration and the weakening of insulator and shield effect of the solid ice accordingly caused by the increase of air temperature. In sea ice free area of the Norwegian Sea, the sensible heat flux and latent heat flux sent to the atmosphere has reduced due to decrease of temperature and humidity differences between the air and the sea surface caused by increase of air temperature and humidity. In the Labrador Sea, due to decrease of air temperature and humidity and increase of temperature and humidity differences between the air and the sea surface accordingly, the sea gives more sensible heat flux and latent heat flux to the air. This will lead to the growth of sea ice extent there. The features of linear regression of sea level pressure, sea ice concentration and sum of sensible heat flux and latent heat flux toward time series of the leading mode of EOF expansion of surface air temperature are close to those of

  14. Estimating Arctic sea-ice freeze-up and break-up from the satellite record: A comparison of different approaches in the Chukchi and Beaufort Seas

    Directory of Open Access Journals (Sweden)

    Mark Johnson

    2016-09-01

    Full Text Available 1. Abstract The recognized importance of the annual cycle of sea ice in the Arctic to heat budgets, human behavior, and ecosystem functions, requires consistent definitions of such key events in the ice cycle as break-up and freeze-up. An internally consistent and reproducible approach to characterize the timing of these events in the annual sea-ice cycle is described. An algorithm was developed to calculate the start and end dates of freeze-up and break-up and applied to time series of satellite-derived sea-ice concentration from 1979 to 2013. Our approach builds from discussions with sea-ice experts having experience observing and working on the sea ice in the Bering, Chukchi and Beaufort Seas. Applying the algorithm to the 1979–2013 satellite data reveals that freeze-up is delayed by two weeks per decade for the Chukchi coast and one week per decade for the Beaufort coast. For both regions, break-up start is arriving earlier by 5–7 days per decade and break-up end is arriving earlier by 10–12 days per decade. In the Chukchi Sea, “early” break-up is arriving earlier by one month over the 34-year period and alternates with a “late” break-up. The calculated freeze-up and break-up dates provide information helpful to understanding the dynamics of the annual sea-ice cycle and identifying the drivers that modify this cycle. The algorithm presented here, and potential refinements, can help guide future work on changes in the seasonal cycle of sea ice. The sea-ice phenology of freeze-up and break-up that results from our approach is consistent with observations of sea-ice use. It may be applied to advancing our understanding and prediction of the timing of seasonal navigation, availability of ice as a biological habitat, and assessment of numerical models.

  15. Effects of changing sea ice on marine mammals and subsistence hunters in northern Alaska from traditional knowledge interviews.

    Science.gov (United States)

    Huntington, Henry P; Quakenbush, Lori T; Nelson, Mark

    2016-08-01

    Marine mammals are important sources of food for indigenous residents of northern Alaska. Changing sea ice patterns affect the animals themselves as well as access to them by hunters. Documenting the traditional knowledge of Iñupiaq and Yupik hunters concerning marine mammals and sea ice makes accessible a wide range of information relevant to understanding the ecosystem to which humans belong. We interviewed hunters in 11 coastal villages from the northern Bering Sea to the Beaufort Sea. Hunters reported extensive changes in sea ice and weather that have affected the timing of marine mammal migrations, their distribution and behaviour and the efficacy of certain hunting methods. Amidst these changes, however, hunters cited offsetting technological benefits, such as more powerful and fuel-efficient outboard engines. Other concerns included potential impacts to subsistence hunting from industrial activity such as shipping and oil and gas development. While hunters have been able to adjust to some changes, continued environmental changes and increased disturbance from human activity may further challenge their ability to acquire food in the future. There are indications, however, that innovation and flexibility provide sources of resilience. PMID:27555644

  16. Historical biogeography of fleas: the former Bering Land Bridge and phylogenetic dissimilarity between the Nearctic and Palearctic assemblages.

    Science.gov (United States)

    Krasnov, Boris R; Shenbrot, Georgy I; Khokhlova, Irina S

    2015-05-01

    We investigated the phylogenetic structure of flea assemblages collected from small mammals on opposite sides of and increasing distance from the former Bering Land Bridge (BLB) using crossed double principal coordinate analysis (crossed-DPCoA). Phylogenetic composition of flea assemblages differed substantially between continents, but phylogenetic similarity between the Nearctic and Palearctic assemblages was the highest in the regions closer to the BLB. Within continents, phylogenetic similarity of flea assemblages was lower between regions closer to the BLB and those farther from the BLB than among regions within each of these groups. The Palearctic assemblages were represented mainly by basal families, while the Nearctic assemblages were dominated by a derived family (Ceratophyllidae), suggesting predominantly eastward pre-glaciation movements. In contrast, within the youngest flea family (Ceratophyllidae), the basal clades were characteristic for the Nearctic, while some species of a few derived clades were characteristic for the Palearctic, suggesting that, at least, during glaciation, westward movements occurred as well. In addition, multiple within-family clades of fleas were represented on opposite sides of the BLB suggesting multiple colonization events. This study is the first attempt to apply modern analytical methods of community ecology to reveal patterns in historical biogeography. PMID:25648445

  17. Affects of Changes in Sea Ice Cover on Bowhead Whales and Subsistence Whaling in the Western Arctic

    Science.gov (United States)

    Moore, S.; Suydam, R.; Overland, J.; Laidre, K.; George, J.; Demaster, D.

    2004-12-01

    Global warming may disproportionately affect Arctic marine mammals and disrupt traditional subsistence hunting activities. Based upon analyses of a 24-year time series (1979-2002) of satellite-derived sea ice cover, we identified significant positive trends in the amount of open-water in three large and five small-scale regions in the western Arctic, including habitats where bowhead whales (Balaena mysticetus) feed or are suspected to feed. Bowheads are the only mysticete whale endemic to the Arctic and a cultural keystone species for Native peoples from northwestern Alaska and Chukotka, Russia. While copepods (Calanus spp.) are a mainstay of the bowhead diet, prey sampling conducted in the offshore region of northern Chukotka and stomach contents from whales harvested offshore of the northern Alaskan coast indicate that euphausiids (Thysanoessa spp.) advected from the Bering Sea are also common prey in autumn. Early departure of sea ice has been posited to control availability of zooplankton in the southeastern Bering Sea and in the Cape Bathurst polynya in the southeastern Canadian Beaufort Sea, with maximum secondary production associated with a late phytoplankton bloom in insolatoin-stratified open water. While it is unclear if declining sea-ice has directly affected production or advection of bowhead prey, an extension of the open-water season increases opportunities for Native subsistence whaling in autumn. Therefore, bowhead whales may provide a nexus for simultaneous exploration of the effects sea ice reduction on pagophillic marine mammals and on the social systems of the subsistence hunting community in the western Arctic. The NOAA/Alaska Fisheries Science Center and NSB/Department of Wildlife Management will investigate bowhead whale stock identity, seasonal distribution and subsistence use patterns during the International Polar Year, as an extension of research planned for 2005-06. This research is in response to recommendations from the Scientific

  18. Abundance and distribution of meiofauna in the Chukchi Sea

    Institute of Scientific and Technical Information of China (English)

    LIN Rongcheng; HUANG Dingyong; GUO Yuqing; CHANG Yu; CAO Yinkun; WANG Jianjia

    2014-01-01

    The metazoan meiofauna in the Chukchi Sea were collected from seven shallow water stations (depths rang-ing 46 to 52 m) and five deep sea stations (depths ranging between 393 and 2 300 m) during the 4th Chinese National Arctic Research Expedition in 2010. The results showed that abundance of meiofauna was higher in shallow water sediments (average of 2 445 ind./(10 cm2)) than in deep sea sediments (407.06 ind./(10 cm2)). A UNIANOVA test for difference between the two different regions was highly significant (F=101.15, p<0.01). Nematodes were numerically dominant, representing (96.6±4.6)%of the total meiofaunal abundance at the shallow water stations and (98.90±1.42)%at deep sea stations. The number of higher taxonomic groups and abundance of meiofauna were higher at Stas CC1, CC4, and R06 near the Bering Strait and the continent, than at the rest of the shallow water and deep sea stations. The primary factors causing the differences were concentrations of nutrients P and Si of bottom seawater (R=0.831, p<0.003), followed by depth (R=-0.655, p<0.05) and sand fractions of sediments (R=0.632, p<0.05). The numbers of meiofauna on the 65μm and 32μm sieves were significantly higher than those on the rest of the screens. Differences in numbers of meio-fauna retained on screens with different mesh openings were highly significant among all sampling stations (F=31.60, p<0.01). The highest numbers of individuals on screens with 32μm mesh openings were found at deep sea stations. The number of meiofauna in the top 0-1, 1-2, and 2-4 cm segments constituted 84.4%of the total and was significantly higher than those in the bottom 4-6 and 6-10 cm segments (F=15, p<0.01).

  19. Distribution of molluscan remains in the sediment of the Chukchi Sea and its vicinity, the Arctic

    Institute of Scientific and Technical Information of China (English)

    Gao Aiguo; Xu Fengshan; Sun Haiqing; Li Lon

    2003-01-01

    The result of an analysis of mollusca remains collected from the Chukchi Sea, Beaufort Sea and Bering Sea in the First Chinese National Arctic Research Expedition, from July to September,1999 is presented. Seventeen species of mollusca have been identified, which belong to two classes: Bivalvia and Gastropoda. The compositions of the mollusca are very simple. According to the distribution pattern two groups may be distinguished among molluscan species. The Pan-Arctic and circumboreal group comprises Nuculana pernula, N. radiata, Nucula bellotii, Astarte montagui, Seripes groenlandicus, Macoma calcarea, M. moesta alaskana, Liocyma fluctuosa, Mya pseudoarenaria and Turritella polaris. Three species, Cyclocardia crebricos tata, Trichotrois coronata and Argobuccinum oregonense are components of the Pan-Arctic and Pacific boreal group. With regard to feeding habits, detritus feeders dominate. There are 7 species of detritus feeders, i.e. , Nuculana pernula, N. radiata,Nucula bellotii , Macoma calcarea , M. moesta alaskana , Macoma sp. and Trichotropis coronata . Detritus feeders are dominant with regard to the numbers of species as well as to the frequency of occurrence. Macoma calcarea is the most abundant species.

  20. Holocene Northern Hemisphere sea-ice distribution - proxy data reconstruction and modelling

    Science.gov (United States)

    Seidenkrantz, Marit-Solveig; de Vernal, Anne; Goosse, Hugues; Klein, François; Solignac, Sandrine; Van Nieuwenhove, Nicolas; Pearce, Christof; Caissie, Beth; Belt, Simon; Sha, Longbin; Cronin, Thomas M.; Stein, Rüdiger; Macias-Fauria, Marc; DeNinno, Lauren H.

    2016-04-01

    A strikingly fast decrease of Arctic sea-ice cover has been recorded for the instrumental period and attributed to anthropogenic climate change, but little is known about natural sea-ice variability. Hence, there is a need for longer sea-ice time series to establish a baseline for natural Arctic sea-ice variability. We compiled 120 proxy-based sea-ice reconstructions from the Arctic Ocean and subarctic marginal seas to evaluate the stability/variability of sea-ice cover during the Holocene. The reconstructions are primarily based on published data combined with a few yet-unpublished records of biological (diatoms, dinoflagellate cysts, foraminifera, ostracods), sedimentological (IRD), and biogeochemical (IP25, PIP25, TOC) sea-ice indicators. Each indicator and record has been interpreted independently. We present all data as long-term annual means (months of sea ice per year). Sea-ice reconstructions are grouped into these classes: perennial (11-12 month/yr), dense (6-10 m/yr), common (1-6 m/yr), occasional (0.1-1 m/yr), rare (almost never) and absent (never). Further, reconstructions are made for the time slices 0-2 cal. ka (BP), 2-4 ka, 4-6 ka, 6±0.5 ka, 6-8 ka and 8-10 ka. Our study shows that winter sea ice was present during the entire Holocene, but summer sea ice may have been somewhat reduced in some areas during the Holocene Climate Optimum (10-6 ka), with variations between basins. In the Nordic Seas and N Atlantic minimum sea-ice conditions are seen 10-6 ka, whereas in the eastern Labrador Sea minimum sea-ice occurred 6-4 ka. Since ~4 ka sea-ice cover has increased, especially in the most recent millennia. Changes are subtle, however, but nonetheless consistent. The Pacific sector of the Arctic (Bering, Chukchi, Beaufort, Laptev, Okhotsk seas) shows less variability during the Holocene, though it is noted that these records have poorer age control and resolution than those from the Atlantic sector. It is noteworthy that, within the available temporal

  1. Aral Sea basin: a sea dies, a sea also rises.

    Science.gov (United States)

    Glantz, Michael H

    2007-06-01

    The thesis of this article is quite different from many other theses of papers, books, and articles on the Aral Sea. It is meant to purposely highlight the reality of the situation in Central Asia: the Aral Sea that was once a thriving body of water is no more. That sea is dead. What does exist in its place are the Aral seas: there are in essence three bodies of water, one of which is being purposefully restored and its level is rising (the Little Aral), and two others which are still marginally connected, although they continue to decline in level (the Big Aral West and the Big Aral East). In 1960 the level of the sea was about 53 m above sea level. By 2006 the level had dropped by 23 m to 30 m above sea level. This was not a scenario generated by a computer model. It was a process of environmental degradation played out in real life in a matter of a few decades, primarily as a result of human activities. Despite wishes and words to the contrary, it will take a heroic global effort to save what remains of the Big Aral. It would also take a significant degree of sacrifice by people and governments in the region to restore the Big Aral to an acceptable level, given that the annual rate of flow reaching the Amudarya River delta is less than a 10th of what it was several decades ago. Conferring World Heritage status to the Aral Sea(s) could spark restoration efforts for the Big Aral. PMID:17626470

  2. 7 CFR 1437.310 - Sea grass and sea oats.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Sea grass and sea oats. 1437.310 Section 1437.310 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT... Determining Coverage Using Value § 1437.310 Sea grass and sea oats. (a) Sea grass and sea oats are value...

  3. BS_Q13.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (13 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  4. BS_Q07.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (7 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  5. BS_Q11.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (11 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  6. BS_Q06.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (6 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  7. BS_Q24.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (24 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  8. BS_Q08.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (8 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  9. BS_Q14.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (14 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  10. BS_Q23.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (23 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  11. BS_Q12.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (12 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  12. BS_Q09.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (9 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  13. BS_250M_LCC_NAD27.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar composite mosaic (LCC, 250 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — From 1986 through 1989, the USGS and IOS (Institute of Oceanographic Sciences, U.K.) scientists conducted several surveys within the U.S. EEZ off Alaska. Four...

  14. AFSC/NMML: Killer Whale encounter data in the Aleutian Islands, Bering Sea, and the western and central Gulf of Alaska from 2000 - 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Comprises data from surveys focused on killer whales with opportunistic data from other cetacean species; includes data describing encounters for...

  15. Acoustic-Trawl Survey of Walleye Pollock on the U.S. and Russian Bering Sea Shelf (DY1207, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Midwater Assessment and Conservation Engineering (MACE) program of NOAA National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC)...

  16. Novel insights from NMR spectroscopy into seasonal changes in the composition of dissolved organic matter exported to the Bering Sea by the Yukon River

    Science.gov (United States)

    Cao, Xiaoyan; Aiken, George R.; Spencer, Robert G. M.; Butler, Kenna; Mao, Jingdong; Schmidt-Rohr, Klaus

    2016-01-01

    Seasonal (spring freshet, summer–autumn, and winter) variability in the chemical composition of dissolved organic matter (DOM) from the Yukon River was determined using advanced one- and two-dimensional (2D) solid-state NMR spectroscopy, coupled with isotopic measurements and UV–visible spectroscopy. Analyses were performed on two major DOM fractions, the hydrophobic organic acid (HPOA) and transphilic organic acid (TPIA) fractions obtained using XAD resins. Together these two fractions comprised 64–74% of the total DOM. Carboxyl-rich alicyclic molecules (CRAM) accounted for the majority of carbon atoms in the HPOA (63–77%) and TPIA (54–78%) samples, and more so in winter and summer than in spring samples. 2D and selective NMR data revealed association of abundant nonprotonated O-alkyl and quaternary alkyl C (OCnp, OCnpO and Cq, 13–17% of HPOA and 15–20% of TPIA) and isolated O–CH structures with CRAM, which were not recognized in previous studies. Spectral editing and 2D NMR allowed for the discrimination of carbohydrate-like O-alkyl C from non-carbohydrate O-alkyl C. Whereas two spring freshet TPIA samples contained carbohydrate clusters such as carboxylated carbohydrates (16% and 26%), TPIA samples from other seasons or HPOA samples mostly had small amounts (exported by the Yukon River across different seasons, due to the predominance of CRAM and their associated nonprotonated C–O and O–C–O structures, and elevated reactivity (bio- and photo-lability) of spring DOM due to the presence of terrestrial inputs enriched in carbohydrates and aromatic structures.

  17. AFSC/NMML Location-only satellite telemetry data for gray whales in the Bering and Chukchi Sea, 2012-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains ARGOS location data (latitude and longitude in decimal format) and associated time (date and time) and location quality (as defined by Argos...

  18. Selected bibliography on birds in the Bering Sea and the Arctic Ocean as related to outer continental shelf areas under consideration for leasing: Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This bibliography lists published and unpublished references to the bird resources within or near the areas of Alaska's outer continental shelf that have been...

  19. BS_Q02.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (2 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  20. BS_Q21.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (21 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  1. Novel insights from NMR spectroscopy into seasonal changes in the composition of dissolved organic matter exported to the Bering Sea by the Yukon River

    Science.gov (United States)

    Cao, Xiaoyan; Aiken, George R.; Spencer, Robert G. M.; Butler, Kenna; Mao, Jingdong; Schmidt-Rohr, Klaus

    2016-05-01

    Seasonal (spring freshet, summer-autumn, and winter) variability in the chemical composition of dissolved organic matter (DOM) from the Yukon River was determined using advanced one- and two-dimensional (2D) solid-state NMR spectroscopy, coupled with isotopic measurements and UV-visible spectroscopy. Analyses were performed on two major DOM fractions, the hydrophobic organic acid (HPOA) and transphilic organic acid (TPIA) fractions obtained using XAD resins. Together these two fractions comprised 64-74% of the total DOM. Carboxyl-rich alicyclic molecules (CRAM) accounted for the majority of carbon atoms in the HPOA (63-77%) and TPIA (54-78%) samples, and more so in winter and summer than in spring samples. 2D and selective NMR data revealed association of abundant nonprotonated O-alkyl and quaternary alkyl C (OCnp, OCnpO and Cq, 13-17% of HPOA and 15-20% of TPIA) and isolated O-CH structures with CRAM, which were not recognized in previous studies. Spectral editing and 2D NMR allowed for the discrimination of carbohydrate-like O-alkyl C from non-carbohydrate O-alkyl C. Whereas two spring freshet TPIA samples contained carbohydrate clusters such as carboxylated carbohydrates (16% and 26%), TPIA samples from other seasons or HPOA samples mostly had small amounts (exported by the Yukon River across different seasons, due to the predominance of CRAM and their associated nonprotonated C-O and O-C-O structures, and elevated reactivity (bio- and photo-lability) of spring DOM due to the presence of terrestrial inputs enriched in carbohydrates and aromatic structures.

  2. Periodic bowhead whale aerial surveys by the USDI/Minerals Management Service in the Bering, Chukchi and Beaufort Seas, April 1979 - October 2001 (NODC Accession 0001139)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  3. BS_Q01.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (1 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  4. BS_Q16.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (16 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  5. BS_Q22B.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (30 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  6. BS_Q19.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (19 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  7. BS_Q18.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (18 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  8. BS_Q10.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (10 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  9. BS_Q17.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (17 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  10. BS_Q13B.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (28 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  11. BS_Q04.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (4 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  12. BS_Q14B.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (29 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  13. BS_Q03.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (3 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  14. BS_Q06B.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (27 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  15. BS_Q20.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (20 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  16. BS_Q05.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (5 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  17. BS_Q22.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (22 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  18. BS_Q25.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (25 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  19. AFSC/ABL: Intra-annual growth in body weight of chum salmon captured incidentally in the Bering Sea commercial fishery for walleye pollock

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ecosystem-based fisheries management requires the development of physical and biological time series that index ocean productivity for stock assessment and...

  20. AFSC/ABL: Genetic data for juvenile chum salmon samples collected in the eastern Bering Sea on the U.S. BASIS cruises during 2003-2007.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chum salmon (Oncorhynchus keta) are an important natural resource in western Alaska for subsistence, commercial and cultural reasons. Declines in chum salmon...

  1. AFSC/RACE/GAP/vonSzalay: The Eastern Bering Sea Shelf, Gulf of Alaska, and Aleutian Islands Simrad ES 60 Acoustic Data Collected on Bottom Trawl Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Calibrated midwater and bottom backscatter data collected continuously with ES-60 echosounders throughout the bottom trawlsurvey period, continuing a time series of...

  2. Underway meteorological, navigational, physical and time series data collected aboard NOAA Ship Ronald H. Brown in the Bering Sea on 2015-09-04 (NCEI Accession 0137446)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0137446 contains raw underway meteorological, navigational, physical and time series data logged by the Scientific Computer System (SCS) aboard NOAA...

  3. BS_Q26.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (26 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  4. Sea Lion Diet Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — California sea lions pup and breed at four of the nine Channel Islands in southern California. Since 1981, SWFSC MMTD has been conducting a diet study of sea lions...

  5. Sea Turtle Interaction Report

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sea Turtle Interaction Report is a report sent out in pdf format to authorized individuals that summarizes sea turtle interactions in the longline fishery. The...

  6. The Effects of Changing Sea Ice on Marine Mammals and Their Hunters in Northern Alaska

    Science.gov (United States)

    Huntington, H.; Quakenbush, L.; Nelson, M.

    2015-12-01

    Marine mammals are important sources of food for indigenous residents of northern Alaska. Changing sea ice patterns affect the animals themselves as well as access by hunters. Documenting the traditional knowledge of Iñupiaq and Yupik hunters concerning marine mammals and sea ice makes accessible a wide range of information and insight relevant to ecological understanding, conservation action, and the regulation of human activity. We interviewed hunters in villages from northern Bering Sea to the Beaufort Sea, focusing on bowhead whales, walrus, and ice seals. Hunters reported extensive changes in sea ice, with resulting effects on the timing of marine mammal migrations, the distribution and behavior of the animals, and the efficacy of certain hunting methods, for example the difficulty of finding ice thick enough to support a bowhead whale for butchering. At the same time, hunters acknowledged impacts and potential impacts from changing technology such as more powerful outboard engines and from industrial activity such as shipping and oil and gas development. Hunters have been able to adapt to some changes, for example by hunting bowhead whales in fall as well as spring on St. Lawrence Island, or by focusing their hunt in a shorter period in Nuiqsut to accommodate work schedules and worse weather. Other changes, such as reduced availability of ice seals due to rapid retreat of pack ice after spring break-up, continue to defy easy responses. Continued environmental changes, increased disturbance from human activity, and the introduction of new regulations for hunting may further challenge the ability of hunters to provide food as they have done to date, though innovation and flexibility may also provide new sources of adaptation.

  7. Sea level rise

    OpenAIRE

    Warrick, R. A.; Oerlemans, J.

    1990-01-01

    This Section addresses three questions: Has global-mean sea level been rising during the last 100 years? What are the causal factors that could explain a past rise in sea level? And what increases in sea level can be expected in the future?

  8. What happened to gray whales during the Pleistocene? The ecological impact of sea-level change on benthic feeding areas in the North Pacific Ocean.

    Directory of Open Access Journals (Sweden)

    Nicholas D Pyenson

    Full Text Available BACKGROUND: Gray whales (Eschrichtius robustus undertake long migrations, from Baja California to Alaska, to feed on seasonally productive benthos of the Bering and Chukchi seas. The invertebrates that form their primary prey are restricted to shallow water environments, but global sea-level changes during the Pleistocene eliminated or reduced this critical habitat multiple times. Because the fossil record of gray whales is coincident with the onset of Northern Hemisphere glaciation, gray whales survived these massive changes to their feeding habitat, but it is unclear how. METHODOLOGY/PRINCIPAL FINDINGS: We reconstructed gray whale carrying capacity fluctuations during the past 120,000 years by quantifying gray whale feeding habitat availability using bathymetric data for the North Pacific Ocean, constrained by their maximum diving depth. We calculated carrying capacity based on modern estimates of metabolic demand, prey availability, and feeding duration; we also constrained our estimates to reflect current population size and account for glaciated and non-glaciated areas in the North Pacific. Our results show that key feeding areas eliminated by sea-level lowstands were not replaced by commensurate areas. Our reconstructions show that such reductions affected carrying capacity, and harmonic means of these fluctuations do not differ dramatically from genetic estimates of carrying capacity. CONCLUSIONS/SIGNIFICANCE: Assuming current carrying capacity estimates, Pleistocene glacial maxima may have created multiple, weak genetic bottlenecks, although the current temporal resolution of genetic datasets does not test for such signals. Our results do not, however, falsify molecular estimates of pre-whaling population size because those abundances would have been sufficient to survive the loss of major benthic feeding areas (i.e., the majority of the Bering Shelf during glacial maxima. We propose that gray whales survived the disappearance of their

  9. Temperature, salinity, velocity including ADCP ice tracking, and bottom pressure collected by Bering Strait Moorings A1W, A1, A1E, A2W, A2, A4W, A4, A3 from 2009-08-26 to 2010-08-03 (NCEI Accession 0138582)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data from moorings deployed in Bering Strait from summer 2009 to summer 2010. Mooring deployments were funded by the NOAA RUSALCA (Russian-US...

  10. Oceanographic station data from bottle casts from the BERING STRAIT and COOK INLET from Ocean Weather Station D (OWS-D) and V (OWS-V) in the North Atlantic Ocean and North Pacific Ocean 15 July 1968 to 25 August 1968 (NODC Accession 6800290)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic station data were collected from the BERING STRAIT and COOK INLET within a 1-mile radius of Ocean Weather Station D (4400N 04100W), V (3400N 16400E),...

  11. Oceanographic station data from bottle casts from the BERING STRAIT, GRESHAM, and SOUTHWIND and other platforms from multiple Ocean Weather Station (OWS) in the North Atlantic Ocean and North Pacific Ocean from 06 September 1969 to 30 September 1969 (NODC Accession 7000060)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic station data were collected from the BERING STRAIT, GRESHAM, and SOUTHWIND and other platforms within a 1-mile radius of Ocean Weather Station A...

  12. Sea piracy and law of the sea

    OpenAIRE

    Hanif, Muhammad Tahir

    2010-01-01

    As the sea become world’s largest source to trade between the nations during the last few decades. Of course there are lots of problems in this regards when we are using the sea on such a large scale. The problem of piracy is most dangerous problems, among the all problems of the sea at the same time. Nations are trying to control this crime individually and collectively but the problem is still on its peak. Lots of international and national laws and conventions are held in this ...

  13. Salish Sea Genetics - Salish Sea genetic inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Salish Sea comprises most of the Puget Sound water area. Marine species are generally assemblages of discrete populations occupying various ecological niches....

  14. Summer Arctic sea fog

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Synchronous or quasi-synchronous sea-land-air observations were conducted using advanced sea ice, atmospheric and marine instruments during China' s First Arctic Expedition. Based on the Precious data from the expedition, it was found that in the Arctic Ocean, most part of which is covered with ice or is mixed with ice, various kinds of sea fog formed such as advection fog, radiation fog and vapor fog. Each kind has its own characteristic and mechanics of creation. In the southern part of the Arctic Ocean, due to the sufficient warm and wet flow there, it is favorable for advection fog to form,which is dense and lasts a long time. On ice cap or vast floating ice, due to the strong radiation cooling effect, stable radiating fog is likely to form. In floating ice area there forms vapor fog with the appearance of masses of vapor from a boiling pot, which is different from short-lasting land fog. The study indicates that the reason why there are many kinds of sea fog form in the Arctic Ocean is because of the complicated cushion and the consequent sea-air interaction caused by the sea ice distribution and its unique physical characteristics. Sea fog is the atmospheric phenomenon of sea-air heat exchange. Especially, due to the high albedo of ice and snow surface, it is diffcult to absorb great amount of solar radiation during the polar days. Besides, ice is a poor conductor of heat; it blocks the sea-air heat exchange.The sea-air exchange is active in floating ice area where the ice is broken. The sea sends heat to the atmosphere in form of latent heat; vapor fog is a way of sea-air heat exchange influencing the climate and an indicator of the extent of the exchange. The study also indicates that the sea also transports heat to the atmosphere in form of sensible heat when vapor fog occurs.

  15. Circumpolar Arctic greening: Relationships to summer sea-ice concentrations, land temperatures and disturbance regimes

    Science.gov (United States)

    Walker, D. A.; Bhatt, U. S.; Epstein, H. E.; Raynolds, M. K.; Frost, G. V.; Leibman, M. O.; Khomutov, A.; Jia, G.; Comiso, J. C.; Pinzon, J. E.; Tucker, C. J.; Webber, P. J.; Tweedie, C. E.

    2009-12-01

    The global distribution of Arctic tundra vegetation is closely tied to the presence of summer sea ice. Models predict that the reduction of sea ice will cause large changes to summer land-surface temperatures. Warming combined with increased natural and anthropogenic disturbance are expected to greatly increase arctic tundra productivity. To examine where tundra productivity is changing most rapidly, we studied 1982-2008 trends of sea-ice concentrations, summer warmth index (SWI) and the annual Maximum Normalized Difference Vegetation Index (MaxNDVI). We summarize the results according to the tundra adjacent to 14 Arctic seas. Sea-ice concentrations have declined and summer land temperatures have increased in all parts of the Arctic coast. The overall percentage increase in Arctic MaxNDVI was +7%. The trend was much greater in North America (+11%) than in Eurasia (+4%). Large percentage increases of MaxNDVI occurred inland from Davis Straight (+20%), Baffin Bay (+18%), Canadian Archipelago (+14%), Beaufort Sea (+12%), and Laptev Sea (+8%). Declines occurred in the W. Chukchi (-6%) and E. Bering (-5%) seas. The changes in NDVI are strongly correlated to changes in summer ground temperatures. Two examples from a 900-km north-south Arctic transect in Russia and long-term observations at a High Arctic site in Canada provide insights to where the changes in productivity are occurring most rapidly. At tree line near Kharp in northwest Siberia, alder shrubs are expanding vigorously in fire-disturbed areas; seedling establishment is occurring primarily in areas with disturbed mineral soils, particularly nonsorted circles. In the Low Arctic tundra areas of the central Yamal Peninsula greening is concentrated in riparian areas and upland landslides associated with degrading massive ground ice, where low-willow shrublands replace the zonal sedge, dwarf-shrub tundra growing on nutrient-poor sands. In polar desert landscapes near the Barnes Ice Cap, Baffin Island, Canada

  16. Host specificity of Lepeophtheirus crassus (Wilson and Bere) (Copepoda: Caligidae) parasitic on the marlin sucker Remora osteochir (Cuvier) in the Atlantic Ocean.

    Science.gov (United States)

    Ho, Ju-shey; Collete, Bruce B; Madinabeitia, Ione

    2006-10-01

    Three species of remoras--Remora brachyptera (Lowe), Remora osteochir (Cuvier), and Remora remora (Linnaeus)--were collected from 4 species of billfishes--Istiophorus platypterus (Shaw), Makaira nigricans Lacepéde, Tetrapturus albidus Poey, and Tetrapturus pfluegeri Robins and de Sylva--on board a Japanese long-liner Shoyo Maru during her cruise in 2002 across the Atlantic. However, only the marlin sucker (R. osteochir) was found to carry a parasitic copepod, Lepeophtheirus crassus (Wilson and Bere, 1936). Although 12 species of parasitic copepods have been reported from billfishes around the world ocean, none of them is L. crassus. Thus, L. crassus is considered a parasite specific to the marlin sucker. PMID:17152964

  17. South China Sea Challenge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    China's attempts to solve disputes with ASEAN over the South China Sea help regional peace China's marine economy and security are currently faced with new challenges, requiring careful handling, especially in disputes with ASEAN countries and in promoting common development of the South China Sea. The outcome of how this is dealt with could undoubtedly pave the way for solutions to other oceanic disputes. The South China Sea is located south of

  18. SEA and planning

    DEFF Research Database (Denmark)

    Stoeglehner, G.; Brown, A.L.; Kørnøv, Lone

    2009-01-01

    As the field of strategic environmental assessment (SEA) has matured, the focus has moved from the development of legislation, guidelines and methodologies towards improving the effectiveness of SEA. Measuring and of course achieving effectiveness is both complex and challenging. This paper......, and the relationship of the SEA to the planning activity itself. This paper focuses on the influence that planners have in these implementation processes, postulating the hypothesis that these are key players in achieving effectiveness in SEA. Based upon implementation theory and empirical experience, the paper...

  19. Status and trends of sea otters in the northern Pacific Ocean

    Science.gov (United States)

    Bodkin, James L.; Estes, James A.; Jameson, Ronald J.; LaRoe, E.T.; Farris, G.S.; Puckett, C.E.; Doran, P.D.; Mac, M.J.

    1995-01-01

    kelp forest communities. At the same time, sea otter predation on other marine invertebrates can lead to direct competition with humans for resources. These interactions add complex dimensions to the conservation and management of sea otters, in large part because of wide-ranging social, ecological, and economic consequences of sea otter foraging. Long-term data on abundance and distribution are available for relatively few sea otter populations. Here we summarize such data from three populations: Being Island, Russia; Prince William Sound, Alaska; and Olympic Peninsula, Washington. The Bering Island population resulted from natural emigration and represents complete recovery. Prince William Sounds represents near recovery of a remnant population, whereas the Washington population was established via translocations from Alaska and is just beginning to recover. We will compare growth rates and current status among these populations. Because of its unique status and growth characteristics, the California sea otter is not treated in this article.

  20. Sea surface temperatures and salinities from platforms in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and the South China Sea (Nan Hai) from 1896-1950 (NODC Accession 0000506)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface temperatures and salinities were collected in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and South China Sea (Nan Hai)...