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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. 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.

  3. Bering Sea National Wildlife Refuge Wilderness study area

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a brief report on a wilderness study area located in the Bering Sea National Wildlife Refuge now part of the Alaska Maritime National Wildlife...

  4. 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.

  5. 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.

  6. 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

  7. 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...

  8. 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.

  9. 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.

  10. Introduction to Pliocene-Pleistocene paleoceanography of the Bering Sea

    Science.gov (United States)

    Takahashi, Kozo; Ravelo, A. Christina; Okazaki, Yusuke

    2016-03-01

    High resolution paleoceanography of the Pliocene-Pleistocene is important in understanding climate forcing mechanisms and associated environmental changes during this major transition from global warmth to the Ice Ages. This is particularly true in high latitude marginal seas such as the Bering Sea. The Bering Sea 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 the aim to reveal the climate and oceanographic history of the Bering Sea over the past 5 My, IODP Expedition 323 cored a total of 5741 m of sediment (97.4% recovery) at seven sites in 2009 on D/V JOIDES Resolution covering three regions: the Umnak Plateau, the Bowers Ridge, and the Bering Slope. The water depths of the drill sites range from 818 m to 3174 m, allowing for the characterization of past vertical water mass distribution including changes in the oxygen minimum zone. The four deepest holes range from 600 m to 745 m below the seafloor, and resulted in the recovery of long sediment sequences ranging from 1.9 My to 5 My in age. Following the expedition, two sampling parties at Kochi Core Center (for acquisition of ca. 58,000 subsamples) and two scientific meetings were conducted in order to proceed with the analyses of sediment core samples and discussions. Here, pertinent results, primarily from IODP Expedition 323, are consolidated as a single special volume of Deep-Sea Research Part II Topical Studies in Oceanography.

  11. 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.

  12. Pleistocene Deep Sea ostracods from the Bering Sea (IODP expedition 323)

    Science.gov (United States)

    Alvarez Zarikian, Carlos A.

    2016-03-01

    The study presents the first Pleistocene (0-1.9 Ma) record of Deep Sea ostracods from the Bering Sea, derived primarily from Integrated Ocean Drilling Program Expedition 323, Site U1344 (59°3.0‧N, 179°12.2‧W, 3171 m of water depth). Deep Sea ostracod abundances in the Bering Sea sediments are some of the lowest that have been recorded in bathyal and abyssal marine environments (water species Krithe sawanensis, Fallacihowella sp. A, Cytheropteron spp., Eucytherura sp., Argilloecia toyamaensis, and Bradleya mesembrina. Less abundant taxa include Munseyella melzeri, Munseyella ristveti, Cluthia sp., Robertsonites hanaii, and Microcythere mediostriata. Some of these taxa (e.g. Fallacihowella sp. A, Bradleya mesembrina, Microcythere mediostriata) are reported for the first time in the North Pacific. The predominance of the genera Krithe, Fallacihowella, Cytheropteron and Argilloecia indicates cold, ventilated bottom waters. The deep Bering Sea ostracod assemblage shares many common and closely related species with continental slope faunas from the Gulf of Alaska, the Okhotsk Sea, the Arctic Ocean, and even the subpolar North Atlantic. A few continental shelf ostracods, such as species of Munseyella and Robertsonites, are present at Sites U1344 and U1343, in the northern slope of the Aleutian Basin. The presence of shallow water ostracods at the Bering Sea slope sites is possibly explained by sea ice rafting. Exceptionally low ostracod abundance in the U1344 record did not permit evaluating links between ostracod faunas and paleoceanographic conditions; however, an increase in ostracod occurrences throughout the middle Pleistocene at Site U1344 appears to correlate with general sea ice expansion in the Bering Sea. High primary surface productivity, high food flux and high sedimentation rates are considered to be the main factors diluting or suppressing Deep Sea ostracods in the Bering Sea, suggesting that ostracods may prefer living in more oligotrophic deep water

  13. 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...

  14. Environmental predictors of ice seal presence in the Bering Sea.

    Directory of Open Access Journals (Sweden)

    Jennifer L Miksis-Olds

    Full Text Available Ice seals overwintering in the Bering Sea are challenged with foraging, finding mates, and maintaining breathing holes in a dark and ice covered environment. Due to the difficulty of studying these species in their natural environment, very little is known about how the seals navigate under ice. Here we identify specific environmental parameters, including components of the ambient background sound, that are predictive of ice seal presence in the Bering Sea. Multi-year mooring deployments provided synoptic time series of acoustic and oceanographic parameters from which environmental parameters predictive of species presence were identified through a series of mixed models. Ice cover and 10 kHz sound level were significant predictors of seal presence, with 40 kHz sound and prey presence (combined with ice cover as potential predictors as well. Ice seal presence showed a strong positive correlation with ice cover and a negative association with 10 kHz environmental sound. On average, there was a 20-30 dB difference between sound levels during solid ice conditions compared to open water or melting conditions, providing a salient acoustic gradient between open water and solid ice conditions by which ice seals could orient. By constantly assessing the acoustic environment associated with the seasonal ice movement in the Bering Sea, it is possible that ice seals could utilize aspects of the soundscape to gauge their safe distance to open water or the ice edge by orienting in the direction of higher sound levels indicative of open water, especially in the frequency range above 1 kHz. In rapidly changing Arctic and sub-Arctic environments, the seasonal ice conditions and soundscapes are likely to change which may impact the ability of animals using ice presence and cues to successfully function during the winter breeding season.

  15. 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,...

  16. 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)...

  17. AFSC/ABL: 2013 Chum Salmon Bycatch Sample Analysis Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A genetic analysis of chum salmon (Oncorhynchus keta) bycatch from the 2013 Bering Sea walleye pollock (Gadus chalcogrammus) trawl fishery was undertaken to...

  18. 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...

  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. 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...

  1. 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....

  2. 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....

  3. 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....

  4. 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....

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. 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.

  1. 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...

  2. 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

    ... GOA (78 FR 13813, March 1, 2013). In accordance with Sec. 679.20(d)(2), the Administrator, Alaska... 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...

  3. 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

    ... GOA (76 FR 11139, March 1, 2011) and apportionment of non-specified reserves (76 FR 53840, August 30... 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...

  4. 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...

  5. 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...

  6. 78 FR 15677 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-03-12

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

  7. 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....

  8. 76 FR 13593 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-03-14

    ... Amendments 18 and 19 were published on March 2, 2005 (70 FR 10174), and are located at 50 CFR part 680... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab Rationalization Program; Amendment 34 AGENCY... Plan for Bering Sea/Aleutian Islands King and Tanner Crabs to NMFS for review. If approved,...

  9. 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...

  10. 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.

  11. 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.

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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

  19. 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.

  20. 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.

  1. Ecosystem response to a temporary sea ice retreat in the Bering Sea: Winter 2009

    Science.gov (United States)

    Miksis-Olds, Jennifer L.; Stabeno, Phyllis J.; Napp, Jeffery M.; Pinchuk, Alexei I.; Nystuen, Jeffrey A.; Warren, Joseph D.; Denes, Samuel L.

    2013-04-01

    Adding acoustic systems onto ocean moorings and observatories provides additional data to more fully document ecosystem responses to environmental perturbations. A passive acoustic recorder and three-frequency echosounder system were integrated into a biophysical mooring on the central eastern Bering Sea continental shelf. An unexpected, transient, mid-winter retreat of the seasonal sea ice was observed over the mooring for a 2-week period in March 2009. Interpretation of the passive acoustic data provided information about sea ice conditions and included the detection and identification of vocalizing marine mammals, while the acoustic backscatter provided information on relative zooplankton and fish abundance before, during, and after the retreat. Hydrographic data confirmed the acoustic signal was associated with changing surface ice conditions, and the combined information from the biophysical mooring sensors revealed changes in winter trophic level dynamics during the retreat, which would have otherwise been undetected by traditional ship-based observations. Changes in the acoustic environment, zooplankton dynamics, and acoustic detection of marine mammals were observed amidst a physically stable and uniform water column with no indication of a phytoplankton bloom. These data demonstrate the value of acoustic technologies to monitor changing ecosystems dynamics in remote and hazardous locations.

  2. Foods of Spectacled Eiders Somateria fischeri in the Bering Sea, Alaska

    Science.gov (United States)

    Petersen, M.R.; Piatt, J.F.; Trust, K.A.

    1998-01-01

    The winter diet of Spectacled Eiders living in marine habitats is known only from two individuals described by Cottam (1939). Here we examine marine diets from 36 stomachs collected near St. Lawrence Island, Bering Sea, Alaska, during May-June in 1987 and 1992. All Spectacled Eiders ate Mollusca, including Gastropoda (snails; frequency of occurrence 20.0%; sole taxon 0.0%) and Bivalvia (bivalves; 80.0%; 48.0%), and Crustacea (barnacles, amphipods and crabs; 30.6%; 0.0%). One bird ate a cod. The predominant species group eaten was Macoma Clams (72.0%; 36.0%). Prey species of Spectacled Eiders occur predominantly in waters 25-60 m deep in the Bering Sea. To obtain these prey, especially the bivalves, on the winter area Spectacled Eiders must forage in waters exceeding 40 m. We speculate that Spectacled Eiders regularly forage at depths of 45-70 m throughout winter.

  3. 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...

  4. Cooperation and quality of life among Bering Sea fishermen and their families

    OpenAIRE

    Robinson, Thomas F.

    2007-01-01

    Bering Sea pollock fishing is characterized by high levels of physical risk, uncertainties in wages and schedule, close and extensive interdependence on other workers, and long absences from home. This occupation leads to a way of life which is full of extremes and has unusually strong effects on the family. This study examines the effects of the occupation on the quality of family life and working life through a teamwork perspective. It is a study of the slow breakdown in c...

  5. Variation in the occurrence of marine birds at fronts in the Bering Sea

    OpenAIRE

    Schneider, D.; Harrison, NM; Hunt, GL

    1987-01-01

    Topographically-induced flow gradients can concentrate seabird prey in several different ways, and are potentially important to marine birds in shelf ecosystems such as the south-eastern Bering Sea. We tested the hypothesis that attendance by seabirds was greater at fronts maintained by strong surface flow gradients than at fronts maintained by weak or intermittent surface flow gradients. An analysis of 62 crossings of flow gradients identified from temperature and salinity gradients showed t...

  6. 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.

  7. 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

  8. 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

  9. Determination of multiple toxins in whelk and clam samples collected from the Chukchi and Bering seas.

    Science.gov (United States)

    Li, Aifeng; Chen, Huidan; Qiu, Jiangbing; Lin, Heshan; Gu, Haifeng

    2016-01-01

    Buccinidae whelk Neptunea varicifera (Dall), Cardiidae clam Serripes laperousii (Deshayes), and two unknown species of whelk and clam were collected from the Arctic Chukchi Sea and sub-Arctic Bering Sea in July 2014. In this study, the mollusk samples were analyzed by different liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) methods for multiple shellfish toxins, including okadaic acid (OA), pectenotoxin (PTX), yessotoxin (YTX), azaspiracid (AZA), cyclic imines (CI), and saxitoxin (STX) groups. PTX2 (≈2.0 μg kg(-1) whole tissues) was detected exclusively in the clam S. laperousii collected from the Chukchi Sea. OA and dinophysistoxin-1 (DTX1) were restricted to mollusk samples collected from the Bering Sea, and OA was the dominant component of the whelk N. varicifera (63 μg kg(-1) digestive gland) and an unknown species of whelk (6.8 μg kg(-1) digestive gland). Spirolide-1 (SPX1) was confirmed in most samples except for the whelk N. varicifera collected from the Bering Sea. The highest content of SPX1 (≈18.5 μg kg(-1) digestive gland) occurred in the whelk N. varicifera collected from the Chukchi Sea, along with the suspected presence of SPX-C, SPX-D and didesMe-SPX-C. YTX, as well as its derivatives 45-OH-YTX and 45,46,47-Trinor-YTX, were found in all samples, with the highest YTX content (66 μg kg(-1) digestive gland) present in the whelk N. varicifera collected from the Chukchi Sea. Interestingly, STX and dcSTX were measured only in the whelk N. varicifera and unknown species of clam collected from the Chukchi Sea. No AZA-group toxins, gymnodimine (GYM), or pinnatoxin G were found in any samples analyzed. Results demonstrated that the mollusk samples were contaminated by multiple shellfish toxins in the Chukchi and Bering seas. This study highlights the need to monitor potentially toxic microalgae in the Arctic and sub-Arctic regions, as well as species of mollusk that may be included in future commercial or

  10. 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.

  11. 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.

  12. 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.

  13. Side-scan sonar assessment of gray whale feeding in the Bering Sea

    Science.gov (United States)

    Johnson, K.R.; Nelson, C.H.

    1984-01-01

    Side-scan sonar was used to map and measure feeding pits of the California gray whale over 22,000 square kilometers of the northeastern Bering Sea floor. The distribution of pits, feeding whales, ampeliscid amphipods (whale prey), and a fine-sand substrate bearing the amphipods were all closely correlated. The central Chirikov Basin and nearshore areas of Saint Lawrence Island supply at least 6.5 percent of the total gray whale food resource in summer. While feeding, the whales resuspend at least 1.2 x 108 cubic meters of sediment annually; this significantly affects the geology and biology of the region.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

    ... tons (mt) by the final 2012 and 2013 harvest specifications for groundfish of the BSAI (77 FR 10669... biological catch in the final 2012 and 2013 harvest specifications for groundfish in the BSAI (77 FR 10669... Economic Zone Off Alaska; Squid in the Bering Sea and Aleutian Islands Management Area AGENCY:...

  20. 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...

  1. 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...

  2. 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...

  3. 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:...

  4. 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:...

  5. Decadal Bering Sea seascape change: consequences for Pacific walruses and indigenous hunters.

    Science.gov (United States)

    Ray, G Carleton; Hufford, Gary L; Overland, James E; Krupnik, Igor; McCormick-Ray, Jerry; Frey, Karen; Labunski, Elizabeth

    2016-01-01

    The most significant factors currently affecting the Pacific walrus (Odobenus rosmarus divergens) population are climate change and consequent changes in sea-ice morphology and dynamics. This paper integrates recent physical sea-ice change in the Bering Sea with biological and ecological conditions of walruses in their winter-spring reproductive habitat. Historically, walrus in winter-spring depended on a critical mass of sea-ice habitat to optimize social networking, reproductive fitness, feeding behavior, migration, and energetic efficiency. During 2003-2013, our cross-disciplinary, multiscale analysis from shipboard observations, satellite imagery, and ice-floe tracking, reinforced by information from indigenous subsistence hunters, documented change of sea-ice structure from a plastic continuum to a "mixing bowl" of ice floes moving more independently. This fragmentation of winter habitat preconditions the walrus population toward dispersal mortality and will also negatively affect the availability of resources for indigenous communities. We urge an expanded research and management agenda that integrates walrus natural history and habitat more completely with changing sea-ice morphology and dynamics at multiple scales, while also meeting the needs of local communities. PMID:27039507

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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℃.

  12. Individual animals and other data collected using visual observations and other instruments from AIRCRAFT in the Bering Sea and other seas from 02 September 1990 to 07 November 1991 (NODC Accession 9200080)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Individual Animal and other data were collected using visual observation and other instruments from AIRCRAFT in the Bering Sea, Chukchi Sea, and Arctic Ocean. Data...

  13. Temperature profile data collected using BT and XBT casts from the NOAA Ship RESEARCHER and other platforms in the Bering Sea and other Sea areas from 25 February 1987 to 27 July 1987 (NODC Accession 8700280)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile data were collected using XBT and BT casts from the NOAA Ship RESEARCHER and other platforms in the Bering Sea and other Sea areas from 25...

  14. 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...

  15. 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...

  16. 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...

  17. 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....

  18. 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...

  19. 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...

  20. AFSC/RACE/SAP: Detailed Crab Data From NOAA Fisheries Service Annual Eastern Bering Sea Summer Bottom Trawl Surveys 1975 - 2014

    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...

  1. Zooplankton data collected from zooplankton net by PERVENETS in the Bering Sea from 13 July 1959 to 12 August 1959 (NODC Accession 9500034)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data were collected by PERVENETS using zooplankton net casts in the Bering Sea. Data were collected from 13 July 1959 to 12 August 1959 by Pacific...

  2. 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 — Sitespecific 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 studies...

  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. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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 Jianfang; ZHU Chun

    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.

  13. Impact of mesoscale eddies on water transport between the Pacific Ocean and the Bering Sea

    CERN Document Server

    Prants, S V; Budyansky, M V; Uleysky, M Yu

    2013-01-01

    Sea surface height anomalies observed by satellites in 1993--2012 are combined with simulation and observations by surface drifters and Argo floats to study water flow pattern in the Near Strait (NS) connected the Pacific Ocean with the Bering Sea. Daily Lagrangian latitudinal maps, computed with the AVISO surface velocity field, and calculation of the transport across the strait show that the flow through the NS is highly variable and controlled by mesoscale and submesoscale eddies in the area. On the seasonal scale, the flux through the western part of the NR is negatively correlated with the flux through its eastern part ($r=-0.93$). On the interannual time scale, a significant positive correlation ($r=0.72$) is diagnosed between the NS transport and the wind stress in winter. Increased southward component of the wind stress decreases the northward water transport through the strait. Positive wind stress curl over the strait area in winter--spring generates the cyclonic circulation and thereby enhances the...

  14. Diatom Surface Sediment Assemblages from the Bering Sea Shelf: a Tossed Salad or Faithful Recorder of 50 Years of Environmental Change?

    Science.gov (United States)

    Caissie, B.; Brigham-Grette, J.; Kanamaru-Shinn, K.

    2010-12-01

    Recent environmental change in the Bering Sea includes a shift from the negative to positive phase of the Pacific Decadal Oscillation in 1976/77, a secondary shift in sea level pressure and sea surface temperatures in 1998, increasing sea surface temperatures, an earlier spring, an increase in the number of days that sea ice is present along the shelf-slope break, and a decrease in the number of days that sea ice is present in the Chukchi Sea and Arctic Ocean. These physical changes have manifest biological changes such as a northward migration of invertebrates and fish from the southern Bering Sea and shifts in the timing and duration of sea-ice related primary productivity and the spring bloom. We aim to see if diatom sediment assemblages are faithful recorders of these ecological changes in the Bering Sea or if bioturbation has essentially mixed today’s rapid change down core such that the signal is either muted or no longer apparent. Six continental shelf areas were examined in the Bering Sea ranging from northeast of St. Lawrence Island to the shelf-slope break in the south-central Bering Sea. Diatom assemblages from core tops collected as part of the PROBES program in the 1960s were compared to core tops taken nearby (7 m) multi-year ice so their decline may be related to the decrease in multi-year ice over the past 30 years. Additionally, in most cases, species diversity has declined over the past 50 years with Fragilariopsis oceanica and Fragilariopsis cylindrus accounting for a greater percentage of the sediment assemblages today. These two species are collectively considered indicators of seasonal sea ice; their relative abundance peaks when ice is present for 5 months per year. Ongoing down core analyses in these six areas will further reveal the nature of these assemblage changes.

  15. Recruitment variation of eastern Bering Sea crabs: Climate-forcing or top-down effects?

    Science.gov (United States)

    Zheng, Jie; Kruse, Gordon H.

    2006-02-01

    During the last three decades, population abundances of eastern Bering Sea (EBS) crab stocks fluctuated greatly, driven by highly variable recruitment. In recent years, abundances of these stocks have been very low compared to historical levels. This study aims to understand recruitment variation of six stocks of red king ( Paralithodes camtschaticus), blue king ( P. platypus), Tanner ( Chionoecetes bairdi), and snow ( C. opilio) crabs in the EBS. Most crab recruitment time series are not significantly correlated with each other. Spatial distributions of three broadly distributed crab stocks (EBS snow and Tanner crabs and Bristol Bay red king crab) have changed considerably over time, possibly related in part to the regime shift in climate and physical oceanography in 1976-1977. Three climate-forcing hypotheses on larval survival have been proposed to explain crab recruitment variation of Bristol Bay red king crab and EBS Tanner and snow crabs. Some empirical evidence supports speculation that groundfish predation may play an important role in crab recruitment success in the EBS. However, spatial dynamics in the geographic distributions of groundfish and crabs over time make it difficult to relate crab recruitment strength to groundfish biomass. Comprehensive field and spatially explicit modeling studies are needed to test the hypotheses and better understand the relative importance and compound effects of bottom-up and top-down controls on crab recruitment.

  16. 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.

  17. From the Pacific to the Arctic: Paleoclimatic History of the Gulf of Alaska and the Bering Sea (Invited)

    Science.gov (United States)

    Mix, A. C.; Davies, M. H.; Praetorius, S.; Cook, M. S.; Prahl, F. G.; Schmittner, A.; Asahi, H.; Belanger, C. L.; Stoner, J. S.; St-Onge, G.; Jaeger, J. M.; Gulick, S. P.

    2013-12-01

    The Pacific Gateway to the Arctic, ranging from the high North Pacific through the Bering Sea and Bering Strait, remains among the poorest known components of the global climate system; its paleoclimate record is undersampled, misunderstood, and filled with controversy. We know relatively little about the history of Cordilleran ice beyond the last deglaciation; there are vigorous disagreements about the sign, let alone the magnitude, of sea-surface temperate changes and sea-ice cover. The causes of subsurface ocean change and linkages to surface climate are debated, and various models disagree on many aspects. This region is a sensitive part of the climate system, potentially poised near a threshold and with the power to influence North American and global heat and moisture transports through its influence on westerly winds and planetary waves. Little deep or intermediate water forms here today due to excess freshwater input relative to evaporation, but this may have changed in the past, with major consequences for oceanic heat transports, chemical budgets, and the global carbon cycle. Here we compare the records from the Gulf of Alaska and the Bering Sea from the sea surface to the abyss. The Gulf of Alaska, recently drilled by IODP Expedition 341, is dominated by massive input of terrigenous sediments, freshwater flows off the continent that fuels a vigorous coastal current, and boundary downwelling adjacent to the iron-limited subpolar gyre. This region offers a high-resolution view of dynamic advances and retreats of the seaward outlets of Cordilleran Ice Sheet; isostatic responses of the shelf to ice loading reduces the local influence of global sealevel sealevel. In contrast, the Bering Sea, drilled in 2009 by IODP Expedition 323, is a relatively isolated basin, highly biogenic in character, and displays a response to global sealevel change relative to its mostly unglaciated shelf and intermittent subaerial exposure of Beringia, with more frequent intervals

  18. 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

  19. 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.

  20. Remote Correlation of Paleoceanographic Events in the Northern Parts of Bering and Barents Seas during the Termination I and Early Holocene

    Science.gov (United States)

    Ivanova, E. V.; Ovsepyan, E.; Murdmaa, I.; de Vernal, A.; Risebrobakken, B.; Seitkalieva, E.; Radionova, E.; Alekhina, G.

    2014-12-01

    The Barents and Bering seas are closely linked to the High Arctic and to the THC by marine gateways as well as by land-sea and ocean-atmosphere interactions. Our multi-proxy time series demonstrate that these remote seas exhibited dramatic changes during the deglaciation through a succession of global and regional paleoceanographic events including the beginning of Termination I (BT1), Heinrich-1 or Oldest Dryas (OD), Bølling-Allerød (B/A), Younger Dryas (YD) and early Holocene (EH). In the NW Barents Sea, the increased subsurface-to-bottom Atlantic water inflow via the Kvitøya-Erik Eriksen trough (cores S 2519 and S 2528) is inferred at the late OD, late B/A and late YD/EH transition. These events are generally coupled with the strengthened AMOC. A remarkable sea surface warming and sea ice retreat are documented at ~ 13 ka BP. Surface warming and strong Atlantic water inflow were followed by intense iceberg calving in the Erik Eriksen Trough as indicated by the high IRD content of Core S-2519. The rock fragments are unsorted and mainly angular suggesting their ice-rafted (likely iceberg-rafted) origin. Svalbard glaciers apparently derived the material dominated by black schistous mudstones, hard limestones with coral remains, fine-grained sandstones from nearby islands, and icebergs spread it in the Kvitøya-Erik Eriksen Trough during the early deglaciation. The ice rafted coarse terrigenous material supply during the BT1 is also suggested for the NW Bering Sea. In the NW Pacific, NW Bering Sea and Sea of Okhotsk, surface bioproductivity peaked at B/A and EH mainly due to the global warming, enhanced nutrient supply by surface currents from the flooded northeastern shelf, intensified vertical mixing and water exchange through the opened straits. Oxygen-depleted bottom water at intermediate depths characterized several locations including the NW Bering Sea (Core SO201-2-85KL).

  1. Volcano hazards and potential risks on St. Paul Island, Pribilof Islands, Bering Sea, Alaska

    Science.gov (United States)

    Feeley, T. C.; Winer, G. S.

    2009-05-01

    the island. Thus, a new vent could form at any place on the island, including St. Paul's insular shelf and areas farther offshore. Because of the remote location of St. Paul in the storm-lashed Bering Sea, risks related to volcano hazards may be greater than they would be in a different setting where more stable meteorological conditions prevail and access by monitoring and relief groups is less challenging.

  2. Anthropogenic 129I in the North Pacific, Bering and Chukchi Seas, and Arctic Ocean in 2012-2013

    Science.gov (United States)

    Nagai, H.; Hasegawa, A.; Yamagata, T.; Kumamoto, Y.; Nishino, S.; Matsuzaki, H.

    2015-10-01

    Most of anthropogenic 129I in marine environment are due to discharge from the nuclear fuel reprocessing facilities at Sellafield (U.K.) and La Hague (France) for past few decades. The discharge raised 129I concentration in seawaters in the North Atlantic and Arctic Oceans to more than 109 atoms L-1, which is two orders of magnitude higher than that in other region. Recently, in March 2011, a large quantity of 129I was released into the western North Pacific due to the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident. To evaluate the influence of these events, we have measured 129I concentration in seawaters in the northern North Pacific Ocean, Bering and Chukchi Seas, and Arctic Ocean in 2012-2013. The 129I concentrations were 1.0-1.8 × 107 atoms L-1 in the surface waters in the vicinity of 47°N 150°E-130°W North Pacific Ocean, Bering Sea, and Chukchi Sea (<74°N), which are equal to or lower than the 129I concentration level in surface water in the North Pacific Ocean before the F1NPP accident. The vertical profiles in the North Pacific were almost same as that observed in the western North Pacific before the F1NPP accident. The 129I distribution in seawater in the North Pacific to the Chukchi Sea revealed no significant increase of 129I concentration caused by the F1NPP accident. The 129I concentrations were 13-14 × 107 atoms L-1 in surface waters and 80 × 107 atoms L-1 at depths of 300 and 800 m in the Arctic Ocean.

  3. Surface nitrate utilization in the Bering sea since 180 kA BP: Insight from sedimentary nitrogen isotopes

    Science.gov (United States)

    Riethdorf, Jan-Rainer; Thibodeau, Benoit; Ikehara, Minoru; Nürnberg, Dirk; Max, Lars; Tiedemann, Ralf; Yokoyama, Yusuke

    2016-03-01

    We present high-resolution records of sedimentary nitrogen (δ15Nbulk) and carbon isotope ratios (δ13Cbulk) from piston core SO201-2-85KL located in the western Bering Sea. The records reflect changes in surface nitrate utilization and terrestrial organic matter contribution in submillennial resolution that span the last 180 kyr. The δ15Nbulk record is characterized by a minimum during the penultimate interglacial indicating low nitrate utilization (~62-80%) despite the relatively high export production inferred from opal concentrations along with a significant reduction in the terrestrial organic matter fraction (mterr). This suggests that the consumption of the nitrate pool at our site was incomplete and even more reduced than today (~84%). δ15Nbulk increases from Marine Isotope Stage (MIS) 5.4 and culminates during the Last Glacial Maximum, which indicates that nitrate utilization in the Bering Sea was raised during cold intervals (MIS 5.4, 5.2, 4) and almost complete during MIS 3 and 2 (~93-100%). This is in agreement with previous hypotheses suggesting that stronger glacial stratification reduced the nutrient supply from the subeuphotic zone, thereby increasing the iron-to-nutrient ratio and therefore the nitrate utilization in the mixed surface layer. Large variations in δ15Nbulk were also recorded from 180 to 130 ka BP (MIS 6), indicating a potential link to insolation and sea-level forcing and its related feedbacks. Millennial-scale oscillations were observed in δ15Nbulk and δ13Cbulk that might be related to Greenland interstadials.

  4. 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...

  5. 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...

  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 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...

  8. Physical and other data from bottle and CTD casts in the Bering Sea from the OCEANOGRAPHER as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 31 December 1974 to 13 February 1975 (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 the OCEANOGRAPHER. Data were collected by the University of Alaska -...

  9. Bering Sea Inner Front zooplankton, temperature, salinity, and conductivity data sets collected with MOCNESS net on five cruises aboard the ALPHA HELIX, 6/3/1997 - 6/7/1999 (NODC Accession 0000107)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton, temperature, species identification, and other data were collected from ALPHA HELIX using net casts in the Bering Sea. Data were collected from 03 June...

  10. 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...

  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. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  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. 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...

  20. 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...

  1. Physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201506T in the Bering Sea, Gulf of Alaska and North Pacific Ocean from 2015-04-07 to 2015-04-16 (NCEI Accession 0145948)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0145948 includes physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201506T in the Bering Sea, Gulf of Alaska and...

  2. Physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201505S in the Bering Sea from 2015-03-19 to 2015-04-07 (NCEI Accession 0145947)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0145947 includes physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201505S in the Bering Sea from 2015-03-19 to...

  3. 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...

  4. 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....

  5. 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...

  6. 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...

  7. 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...

  8. Marine toxic substance and other data from bottle casts in the Bering Sea from the NOAA Ship DISCOVERER as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 11 May 1981 to 04 June 1981 (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 the NOAA Ship DISCOVERER from 11 May 1981 to 04 June 1981. Data were...

  9. 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...

  10. 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...

  11. Pressure gauge data from the 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 04 August 1983 to 20 September 1983 (NODC Accession 8500087)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure gauge data were collected in the Bering Sea and other locations from the NOAA Ship DISCOVERER and other platforms from 04 August 1983 to 20 September 1983....

  12. 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...

  13. Cetacean line-transect survey conducted in the eastern Bering Sea shelf by Alaska Fisheries Science Center, National Marine Mammal Laboratory from 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...

  14. 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...

  15. 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...

  16. 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...

  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. 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...

  19. 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,...

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

    Data.gov (United States)

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

  1. 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...

  2. 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...

  3. Physical and underway data collected aboard the KNORR during cruise KN195-09 in the Bering Sea and North Pacific Ocean from 2009-06-02 to 2009-06-11 (NODC Accession 0104275)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104275 includes physical and underway data collected aboard the KNORR during cruise KN195-09 in the Bering Sea and North Pacific Ocean from...

  4. 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...

  5. 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,...

  6. 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,...

  7. 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,...

  8. 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...

  9. 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...

  10. 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...

  11. 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....

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. Mineralogical, geochemical and isotopic characterization of authigenic carbonates from the methane-bearing sediments of the Bering Sea continental margin (IODP Expedition 323, Sites U1343-U1345)

    Science.gov (United States)

    Pierre, C.; Blanc-Valleron, M.-M.; Caquineau, S.; März, C.; Ravelo, A. C.; Takahashi, K.; Alvarez Zarikian, C.

    2016-03-01

    During Expedition 323 of the Integrated Ocean Drilling Program to the Bering Sea (July 5-September 4, 2009), three sites were drilled along the Bering Sea northeastern continental margin [U1343 down to 745 meters below sea floor (mbsf), U1344 (745 mbsf), U1345 (150 mbsf)]. Diagenetic carbonates are present at all sites within the clayey, diatom-rich oozes of the Bering Sea, where pore waters are also characterized by extremely high methane concentrations. We here present mineralogical, elemental and isotopic data obtained from the authigenic carbonate-rich intercalations within the clay-rich Pleistocene sediments deposited along the Bering Sea continental margin. The mineralogy of the authigenic carbonates is generally represented by composite mixtures of very small crystals of magnesian calcite, dolomite, and iron-rich carbonates, with the latter phases occurring below 260 mbsf at Site U1343, below 200 mbsf at Site U1344, and below 130 mbsf at Site U1345. Element geochemistry shows that Ca, Mg, Fe, Ba, Mn, Sr and U are enriched in the carbonate-rich intercalations relative to the background sediments due to their incorporation into the carbonates and into other authigenic phases (e.g., barite and pyrite). The oxygen and carbon isotopic compositions of the authigenic carbonate minerals show that they were sequentially precipitated from pore waters at different temperatures (i.e., different burial depths) and with different isotopic compositions of dissolved inorganic carbon (DIC). The authigenic Mg-calcite precipitated early during diagenesis and shallow burial from a 13C-depleted DIC pool, whereas dolomite and Fe-rich carbonates formed during later diagenesis and deeper burial from a 13C-enriched DIC pool. These authigenic carbonate occurrences are interpreted as resulting from microbial sulfate reduction combined with anaerobic oxidation of methane, and methanogenesis that was intimately linked to the alteration of silicates, especially iron-rich clay minerals.

  19. 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...

  20. Accumulation and maternal transfer of polychlorinated biphenyls in Steller Sea Lions (Eumetopias jubatus) from Prince William Sound and the Bering Sea, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jun; Huelck, Kathrin [Department of Molecular Biosciences and Bioengineering, University of Hawaii, 1955 East-West Road, Honolulu, HI 96822 (United States); Hong, Su-Myeong [National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon 441-707 (Korea, Republic of); Atkinson, Shannon [University of Alaska Fairbanks, School of Fisheries and Ocean Sciences Juneau Center, 17101 Pt. Lena Loop Road, Juneau, AK 99801 (United States); Li, Qing X., E-mail: qingl@hawaii.ed [Department of Molecular Biosciences and Bioengineering, University of Hawaii, 1955 East-West Road, Honolulu, HI 96822 (United States)

    2011-01-15

    The western stock of the Steller sea lion (Eumetopias jubatus) in the northern Pacific Ocean has declined by approximately 80% over the past 30 years. This led to the listing of this sea lion population as an endangered species in 1997. Chemical pollution is a one of several contributing causes. In the present study, 145 individual PCBs were determined in tissues of male sea lions from Tatitlek (Prince William Sound) and St. Paul Island (Bering Sea), and placentae from the Aleutian Islands. PCBs 90/101, 118, and 153 were abundant in all the samples. The mean toxic equivalents (TEQ) were 2.6, 4.7 and 7.4 pg/g lw in the kidney, liver, and blubber samples, respectively. The mean TEQ in placentae was 8 pg/g lw. Total PCBs concentrations (2.6-7.9 {mu}g/g lw) in livers of some males were within a range known to cause physiological effects. Further suggesting the possibility of adverse effects on this stock. - PCBs at median concentrations of 1.2-3.7 {mu}g/g lipid weight in different tissues of the western stock of Steller sea lions have physiological effects.

  1. Accumulation and maternal transfer of polychlorinated biphenyls in Steller Sea Lions (Eumetopias jubatus) from Prince William Sound and the Bering Sea, Alaska

    International Nuclear Information System (INIS)

    The western stock of the Steller sea lion (Eumetopias jubatus) in the northern Pacific Ocean has declined by approximately 80% over the past 30 years. This led to the listing of this sea lion population as an endangered species in 1997. Chemical pollution is a one of several contributing causes. In the present study, 145 individual PCBs were determined in tissues of male sea lions from Tatitlek (Prince William Sound) and St. Paul Island (Bering Sea), and placentae from the Aleutian Islands. PCBs 90/101, 118, and 153 were abundant in all the samples. The mean toxic equivalents (TEQ) were 2.6, 4.7 and 7.4 pg/g lw in the kidney, liver, and blubber samples, respectively. The mean TEQ in placentae was 8 pg/g lw. Total PCBs concentrations (2.6-7.9 μg/g lw) in livers of some males were within a range known to cause physiological effects. Further suggesting the possibility of adverse effects on this stock. - PCBs at median concentrations of 1.2-3.7 μg/g lipid weight in different tissues of the western stock of Steller sea lions have physiological effects.

  2. Modeling spatial patterns of limits to production of deposit-feeders and ectothermic predators in the northern Bering Sea

    Science.gov (United States)

    Lovvorn, James R.; Jacob, Ute; North, Christopher A.; Kolts, Jason M.; Grebmeier, Jacqueline M.; Cooper, Lee W.; Cui, Xuehua

    2015-03-01

    Network models can help generate testable predictions and more accurate projections of food web responses to environmental change. Such models depend on predator-prey interactions throughout the network. When a predator currently consumes all of its prey's production, the prey's biomass may change substantially with loss of the predator or invasion by others. Conversely, if production of deposit-feeding prey is limited by organic matter inputs, system response may be predictable from models of primary production. For sea floor communities of shallow Arctic seas, increased temperature could lead to invasion or loss of predators, while reduced sea ice or change in wind-driven currents could alter organic matter inputs. Based on field data and models for three different sectors of the northern Bering Sea, we found a number of cases where all of a prey's production was consumed but the taxa involved varied among sectors. These differences appeared not to result from numerical responses of predators to abundance of preferred prey. Rather, they appeared driven by stochastic variations in relative biomass among taxa, due largely to abiotic conditions that affect colonization and early post-larval survival. Oscillatory tendencies of top-down versus bottom-up interactions may augment these variations. Required inputs of settling microalgae exceeded existing estimates of annual primary production by 50%; thus, assessing limits to bottom-up control depends on better corrections of satellite estimates to account for production throughout the water column. Our results suggest that in this Arctic system, stochastic abiotic conditions outweigh deterministic species interactions in food web responses to a varying environment.

  3. 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.

  4. Development of a Seasonal Extratropical Cyclone Activity Outlook for the North Pacific, Bering Sea, and Alaskan Regions

    Science.gov (United States)

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

    2013-12-01

    Storm activity (i.e. 'storminess') and associated forecasting skill in the North Pacific, Bering Sea, and Alaska is relatively well understood on a daily to weekly scale, however, two important elements are missing from current capacity. First, there is no way to predict storm activity at the monthly to seasonal time frame. Second, storm activity is characterized in terms that best serve weather specialists, and which are often not very informative for different sectors of the public. Increasing the utility of forecasts for end users requires consultation with these groups, and can include expressing storm activity in terms of, for example, strong-wind return intervals or ship hull strength. These types of forecasts can provide valuable information for use in community planning, resource allocation, or potential risk assessment. A preliminary study of seasonal storminess predictability in the North Pacific and Alaska regions has shown that a key factor related to the annual variation of seasonal storminess is the strength of the Aleutian Low as measured using indices such as the North Pacific Index (NPI) or Aleutian Low Pressure Index (ALPI). Use of Empirical Orthogonal Function (EOF) analysis to identify patterns in storminess variability indicates that the primary mode of annual variation is found to be best explained by the variation in the strength of the Aleutian Low. NPI and the first component of storm activity for the entire region are found to be are highly correlated (R = 0.83). This result is supported by the works of others such as Rodionov et al. (2007), who note the impact of the strength of the Aleutian Low on storm track and speed. Additionally, the phase of the Pacific Decadal Oscillation (PDO), along with NPI, have been shown to be highly correlated with annual variance in the seasonal storminess for the North Pacific and Alaska. Additional skill has been identified when the phase of the Pacific Decadal Oscillation (PDO) is explicitly considered

  5. 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....

  6. Comparison of spring-time phytoplankton community composition in two cold years from the western Gulf of Alaska into the southeastern Bering Sea

    Science.gov (United States)

    Stauffer, Beth A.; Goes, Joaquim I.; McKee, Kali T.; do Rosario Gomes, Helga; Stabeno, Phyllis J.

    2014-11-01

    The Bering Sea is a highly productive ecosystem providing the main oceanographic connection between the North Pacific and Arctic oceans. The atmospheric connection with the Arctic Ocean leads to seasonal sea ice formation in the Bering Sea, the areal extent and timing of retreat of which have important implications for primary productivity and phytoplankton community composition in this region. Hydrographic data from cruises and satellite sea ice and sea surface temperature data in spring 2011 and 2012 suggest classification of these years as relatively warmer and colder years, respectively. Locations in the western Gulf of Alaska (Pavlof Bay), at the north end of an eastern pass through the Aleutian Islands (Unimak Pass), and on the continental shelf of the Bering Sea (M2) were visited in both years. Stratification was apparent on the shelf in 2012, while the water column was comparatively well-mixed at other locations in both years. Phytoplankton biomass was highest in 2011 overall and specifically on the shelf in both years, while minimal biomass was measured within the well-mixed Unimak Pass in 2012. Surface phytoplankton size distributions included substantial contributions of picoplankton (<3 μm) in 2011 (21-35%), while micro- (20-200 μm) and nanoplankton (3-20 μm) comprised 79% and 95% of biomass in Pavlof Bay and at M2, respectively, in 2012. Analyses of similarity revealed spatial variability in the phytoplankton assemblages within each year (2011: R=0.588, p<0.004; 2012: R=0.646, p<0.004). Additionally, between-year variability had a strong and significant effect on differences between assemblages across all locations (R=0.579, p<0.0003), likely masking differences between sites when years were grouped (R=0.134, p<0.079). These differences were likely driven by the dominance (up to 75% in Unimak Pass) of the colonial prymnesiophyte Phaeocystis sp. at all sites in 2011, resulting in reduced community diversity, compared to more widespread abundance of

  7. Patterns in connectivity and retention of simulated Tanner crab (Chionoecetes bairdi) larvae in the eastern Bering Sea

    Science.gov (United States)

    Richar, Jonathan I.; Kruse, Gordon H.; Curchitser, Enrique; Hermann, Albert J.

    2015-11-01

    The eastern Bering Sea (EBS) population of Tanner crab (Chionoecetes bairdi) has exhibited high variability in recruitment to the commercially exploited stock since the late 1970s. Concurrently, apparent shifts in crab distribution have also been observed. Larval advection patterns and associated local retention offer a potential mechanism for these observations. The Regional Ocean Modeling System (ROMS) was used to simulate larval Tanner crab advection patterns over 1978-2004 based on larval hatching sites inferred from the distributions of reproductive females sampled during annual National Marine Fisheries Service trawl surveys. Connectivity among EBS subregions was examined by comparing start and end float locations after 60 days of simulated drift. High levels of retention (>50% of floats) were observed in the majority of source subregions, and contributed significantly to the total number of endpoints in each region. Patterns in advection and resultant interregional connectivity were variable, with strongest sustained connectivity occurring along shelf, within individual domains. Increased settlement potential in the outer domain and southern middle domain after 1990 is consistent with an observed geographic shift in fishery productivity. Apparent reliance of Bristol Bay on local larval retention validates recent spatial fishery management to conserve this area as a subpopulation.

  8. A sound budget for the southeastern Bering Sea: measuring wind, rainfall, shipping, and other sources of underwater sound.

    Science.gov (United States)

    Nystuen, Jeffrey A; Moore, Sue E; Stabeno, Phyllis J

    2010-07-01

    Ambient sound in the ocean contains quantifiable information about the marine environment. A passive aquatic listener (PAL) was deployed at a long-term mooring site in the southeastern Bering Sea from 27 April through 28 September 2004. This was a chain mooring with lots of clanking. However, the sampling strategy of the PAL filtered through this noise and allowed the background sound field to be quantified for natural signals. Distinctive signals include the sound from wind, drizzle and rain. These sources dominate the sound budget and their intensity can be used to quantify wind speed and rainfall rate. The wind speed measurement has an accuracy of +/-0.4 m s(-1) when compared to a buoy-mounted anemometer. The rainfall rate measurement is consistent with a land-based measurement in the Aleutian chain at Cold Bay, AK (170 km south of the mooring location). Other identifiable sounds include ships and short transient tones. The PAL was designed to reject transients in the range important for quantification of wind speed and rainfall, but serendipitously recorded peaks in the sound spectrum between 200 Hz and 3 kHz. Some of these tones are consistent with whale calls, but most are apparently associated with mooring self-noise. PMID:20649201

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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

  1. 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.

  2. Synergistic effects of pCO2 and iron availability on nutrient consumption ratio of the Bering Sea phytoplankton community

    Science.gov (United States)

    Sugie, K.; Endo, H.; Suzuki, K.; Nishioka, J.; Kiyosawa, H.; Yoshimura, T.

    2013-10-01

    Little is known concerning the effect of CO2 on phytoplankton ecophysiological processes under nutrient and trace element-limited conditions, because most CO2 manipulation experiments have been conducted under elements-replete conditions. To investigate the effects of CO2 and iron availability on phytoplankton ecophysiology, we conducted an experiment in September 2009 using a phytoplankton community in the iron limited, high-nutrient, low-chlorophyll (HNLC) region of the Bering Sea basin . Carbonate chemistry was controlled by the bubbling of the several levels of CO2 concentration (180, 380, 600, and 1000 ppm) controlled air, and two iron conditions were established, one with and one without the addition of inorganic iron. We demonstrated that in the iron-limited control conditions, the specific growth rate and the maximum photochemical quantum efficiency (Fv/Fm) of photosystem (PS) II decreased with increasing CO2 levels, suggesting a further decrease in iron bioavailability under the high-CO2 conditions. In addition, biogenic silica to particulate nitrogen and biogenic silica to particulate organic carbon ratios increased from 2.65 to 3.75 and 0.39 to 0.50, respectively, with an increase in the CO2 level in the iron-limited controls. By contrast, the specific growth rate, Fv/Fm values and elemental compositions in the iron-added treatments did not change in response to the CO2 variations, indicating that the addition of iron canceled out the effect of the modulation of iron bioavailability due to the change in carbonate chemistry. Our results suggest that high-CO2 conditions can alter the biogeochemical cycling of nutrients through decreasing iron bioavailability in the iron-limited HNLC regions in the future.

  3. 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.

  4. Synergistic effects of pCO2 and iron availability on nutrient consumption ratio of the Bering Sea phytoplankton community

    Directory of Open Access Journals (Sweden)

    K. Sugie

    2013-10-01

    Full Text Available Little is known concerning the effect of CO2 on phytoplankton ecophysiological processes under nutrient and trace element-limited conditions, because most CO2 manipulation experiments have been conducted under elements-replete conditions. To investigate the effects of CO2 and iron availability on phytoplankton ecophysiology, we conducted an experiment in September 2009 using a phytoplankton community in the iron limited, high-nutrient, low-chlorophyll (HNLC region of the Bering Sea basin . Carbonate chemistry was controlled by the bubbling of the several levels of CO2 concentration (180, 380, 600, and 1000 ppm controlled air, and two iron conditions were established, one with and one without the addition of inorganic iron. We demonstrated that in the iron-limited control conditions, the specific growth rate and the maximum photochemical quantum efficiency (Fv/Fm of photosystem (PS II decreased with increasing CO2 levels, suggesting a further decrease in iron bioavailability under the high-CO2 conditions. In addition, biogenic silica to particulate nitrogen and biogenic silica to particulate organic carbon ratios increased from 2.65 to 3.75 and 0.39 to 0.50, respectively, with an increase in the CO2 level in the iron-limited controls. By contrast, the specific growth rate, Fv/Fm values and elemental compositions in the iron-added treatments did not change in response to the CO2 variations, indicating that the addition of iron canceled out the effect of the modulation of iron bioavailability due to the change in carbonate chemistry. Our results suggest that high-CO2 conditions can alter the biogeochemical cycling of nutrients through decreasing iron bioavailability in the iron-limited HNLC regions in the future.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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...

  10. Physical and underway data collected aboard the KNORR during cruise KN195-11 in the Bering Sea from 2009-06-14 to 2009-07-23 (NODC Accession 0104277)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104277 includes physical and underway data collected aboard the KNORR during cruise KN195-11 in the Bering Sea from 2009-06-14 to 2009-07-23. These...

  11. 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...

  12. 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

  13. 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.

  14. Paleomagnetic field variability and chronostratigraphy of Brunhes-Chron deep-sea sediments from the Bering Sea: IODP Expedition 323

    Science.gov (United States)

    Lund, Steve; Stoner, Joseph; Okada, Makoto; Mortazavi, Emily

    2016-03-01

    IODP Expedition 323 recovered six complete and replicate records of Brunhes-Chron paleomagnetic field variability (0-780,000 years BP) in 2820 m core depth below sea floor (CSF) of deep-sea sediments. On shipboard, we made more than 220,000 paleomagnetic measurements on the recovered sediments. Since then, we have u-channel sampled more than 300 m of Brunhes Chron sediments to corroborate our shipboard measurements and improve our paleomagnetic and rock magnetic understanding of these sediments. Several intervals of distinctive paleomagnetic secular variation (PSV) have been identified that appear to be correlatable among sites 1343, 1344, and 1345. One magnetic field excursion is recorded in sediments of sites 1339, 1343, 1344, and 1345. We identify this to be excursion 7α/Iceland Basin Event (192,000 years BP), which is also seen in the high-latitude North Atlantic Ocean (Channell et al., 1997). We have verified in u-channels the placement of the Brunhes/Matuyama boundary (780,000 years BP) at sites 1341 and 1343. Finally, we have developed a medium-quality relative paleointensity record for these sediments that is correlatable among the sites, even though it is still biased by large-amplitude environmental variability. On the basis of these observations we have built a magnetic chronostratigraphy of Expedition 323 sediments suitable for regional correlation and dating over the last 1 million years, and compared this with oxygen-isotope chronostratigraphy from sites U1339 and U1345.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. Oceanographic profile data collected from CTD and sound velocimeter - moving vessel profiler casts aboard FAIRWEATHER as part of project M-R908-FA-08 in the Bering Sea and North Pacific Ocean from 2008-08-08 to 2008-08-09 (NCEI Accession 0130769)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0130769 includes physical and profile data collected aboard the FAIRWEATHER during project M-R908-FA-08 in the Bering Sea and North Pacific Ocean...

  7. Oceanographic profile data collected from CTD and sound velocimeter - moving vessel profiler casts aboard FAIRWEATHER as part of project OPR-R365-FA-10 in the Bering Sea, Coastal Waters of SE Alaska, Gulf of Alaska and North Pacific Ocean from 2010-06-14 to 2010-09-16 (NCEI Accession 0130667)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0130667 includes physical and profile data collected aboard the FAIRWEATHER during project OPR-R365-FA-10 in the Bering Sea, Coastal Waters of SE...

  8. 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...

  9. 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...

  10. 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 07 August 1975 to 21 October 1975 (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 the MILLER FREEMAN and other platforms from 07 August 1975 to 21...

  11. 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....

  12. 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...

  13. 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 27 October 1975 to 12 July 1977 (NODC Accession 7700220)

    Data.gov (United States)

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

  14. 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...

  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. The relationship between sea ice concentration and the spatio-temporal distribution of vocalizing bearded seals (Erignathus barbatus) in the Bering, Chukchi, and Beaufort Seas from 2008 to 2011

    Science.gov (United States)

    MacIntyre, Kalyn Q.; Stafford, Kathleen M.; Conn, Paul B.; Laidre, Kristin L.; Boveng, Peter L.

    2015-08-01

    Bearded seals (Erignathus barbatus) are widely distributed in the Arctic and sub-Arctic; the Beringia population is found throughout the Bering, Chukchi and Beaufort Seas (BCB). Bearded seals are highly vocal, using underwater calls to advertise their breeding condition and maintain aquatic territories. They are also closely associated with pack ice for reproductive activities, molting, and resting. Sea ice habitat for this species varies spatially and temporally throughout the year due to differences in underlying physical and oceanographic features across its range. To test the hypothesis that the vocal activity of bearded seals is related to variations in sea ice, passive acoustic data were collected from nine locations throughout the BCB from 2008 to 2011. Recording instruments sampled on varying duty cycles ranging from 20% to 100% of each hour, and recorded frequencies up to 8192 Hz. Spectrograms of acoustic data were analyzed manually to calculate the daily proportion of hours with bearded seal calls at each sampling location, and these call activity proportions were correlated with daily satellite-derived estimates of sea ice concentration. Bearded seals were vocally active nearly year-round in the Beaufort and Chukchi Seas with peak activity occurring from mid-March to late June during the mating season. The duration of call activity in the Bering Sea was shorter, lasting typically only five months, and peaked from mid-March to May at the northernmost recorders. In all areas, call activity was significantly correlated with higher sea ice concentrations (p losses in ice cover may negatively impact bearded seals, not just by loss of habitat but also by altering the behavioral ecology of the BCB population.

  17. Geochemical characters of Quaternary tephra beds and their stratighraphic position in the sedimentary core drilled at the site U1343 in the central Bering Sea

    Science.gov (United States)

    Aoki, K.; Asahi, H.; Nagatsuma, Y.; Kurihara, K.; Fukuoka, T.; Sakamoto, T.; Iijima, K.

    2012-12-01

    The project IODP exp.323 in the Bering Sea focused on analyzing long-term ocean and climate trends during 5 Ma, and drilled seven sites (sites 1339-1345). Up to now, the studies of long-term tephrochronology in this area are very rare, though a part of histories of several volcanoes and late Pleistocene to Holocene volcanisms and studies for geochemistry of magma were reported in detail. Our objectives are to reveal how many widespread tephras are found in the Bering Sea and which of volcanoes or volcanic zones provided them. First of all, we analyzed forty-eight tephra samples in the sedimentary core collected at site U1343, near the Bering self sloop. Sediments in site U1343 (57°33.4'N, 175°49.0'E, water depth 1956 mbsf, core length 779.18 m) include three paleomagnetic events (the BM boundary;0.788 Ma, Jaramillo; 0.998 Ma, Cobb Mountain;1.173 Ma). The bottom datum event is reported as 2.0-2.2 Ma (diatom) at 716.4 m. All tephra samples were washed by flesh water and decanting, dried up naturally, sieved by the mesh of dia.250, 125 and 63 micrometer. We observed every tephra under the binocular/polarizing microscopes, and analyzed major-element composition of volcanic glass shards by EPMA (10nA, 15kV, probe dia.10 micrometer). All samples include many kinds of volcanic glass shards (color: colorless to dark brown, form: bubble-wall type, pumice type, fiber type). Diameter of grain size is normally less 125 micrometer, and volcanic glass size in some layers is concentrated in the less 63 micrometer. Thickness of tephra samples is approximately 0.5 cm to 4 cm. In the basis of geochemicalc analysis of volcanic glass shards in 48 samples, though every sample includes volcanic glass shards, we can distinguish the two groups roughly; glass-rich samples (31 samples) and contaminated samples (17 samples). Contaminated samples include course sands (lithic fragments, rounded minerals, fossil fragments), besides volcanic glass shards. Number of contaminated samples

  18. 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.

  19. 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

  20. 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.

  1. Cetacean distribution and abundance in relation to oceanographic domains on the eastern Bering Sea shelf, June and July of 2002, 2008, and 2010

    Science.gov (United States)

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

    2013-10-01

    As part of the Bering Sea Project, cetacean surveys were conducted to describe distribution and estimate abundance on the eastern Bering Sea shelf. Three marine mammal observers conducted visual surveys along transect lines sampled during the Alaska Fisheries Science Center walleye pollock assessment survey in June and July of 2008 and 2010. Distribution and abundance in 2008 and 2010 (cold years) are compared with results from a similar survey conducted in 2002 (a warm year), as the only three years that the entire survey area was sampled; patterns largely match those previously observed. Abundance estimates for comparable areas in 2002, 2008 and 2010 were as follows: humpback whales (Megaptera novaeangliae): 231 (CV=0.63), 436 (CV=0.45), and 675 (CV=0.80); fin whales (Balaenoptera physalus): 419 (CV=0.33), 1368 (CV=0.34), and 1061 (CV=0.38); minke whales (Balaenoptera acutorostrata): 389 (CV=0.52), 517 (CV=0.69), and 2020 (CV=0.73); Dall's porpoise (Phocoenoides dalli): 35,303 (CV=0.53), 14,543 (CV=0.32), and 11,143 (CV=0.32); and harbor porpoise (Phocoena phocoena): 1971 (CV=0.46), 4056 (CV=0.40), and 833 (CV=0.66). It should be noted that these abundance estimates are not corrected for biases due to perception, availability, or responsive movement. Estimates for humpback, fin and minke whales increased from 2002 to 2010, while those for harbor and Dall's porpoise decreased; trends were significant for fin whales. It is likely that changes in estimated abundance are due at least in part to shifts in distribution and not just changes in overall population size. Annual abundance estimates were examined by oceanographic domain. Humpback whales were consistently concentrated in coastal waters north of Unimak Pass. Fin whales were broadly distributed in the outer domain and slope in 2008 and 2010, but sightings were sparse in 2002. Minke whales were distributed throughout the study area in 2002 and 2008, but in 2010 they were concentrated in the outer domain and

  2. 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...

  3. 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

  4. High-Resolution Mg/Ca Ratios in a Coralline Red Alga as a Proxy for Bering Sea Temperature Variations and Teleconnections

    Science.gov (United States)

    Halfar, J.; Steffen, H.; Kronz, A.; Steneck, R. S.; Adey, W.; Lebednik, P. A.

    2009-05-01

    We present the first continuous high-resolution record of Mg/Ca variations within an encrusting coralline red alga of the species Clathromorphum nereostratum from Amchitka Island, Aleutian Islands. Mg/Ca ratios of individual growth increments were analyzed by measuring a single point electron microprobe transect yielding a resolution of 15 samples/year on average, generating a continuous record from 1830 to 1967 of algal Mg/Ca variations. Results show that Mg/Ca ratios in the high-Mg calcite skeleton display pronounced annual cyclicity and archive late spring to late fall sea surface temperature (SST) corresponding to the main season of algal growth. Mg/Ca values correlate well to local SST (ERSSTJun-Nov, 1902-1967; r = 0.73 for 5-year mean), as well as to an air temperature record from the same region. Our data correlate well to a shorter Mg/Ca record from a second site, corroborating the ability of the alga to reliably record regional environmental signals. In addition, Mg/Ca ratios relate well to a 29-year stable oxygen isotope time series measured on the same sample, which provides additional support for the use of Mg as a paleotemperature proxy in coralline red algae, that is, unlike stable oxygen isotopes, not influenced by salinity fluctuations. High spatial correlation to large-scale SST variability in the North Pacific is observed, with patterns of strongest correlation following the direction of major oceanographic features (i.e., the signature of the Alaska Current and the Alaskan Stream), which play a key role in the exchange of water masses between the North Pacific and the Bering Sea through Aleutian Island passages. The time series further displays significant teleconnections with the signature of the Pacific Decadal Oscillation in the northeast Pacific and the Atlantic Multidecadal Oscillation.

  5. 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.

  6. 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...

  7. 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 the MILLER FREEMAN in the Bering Sea, Coastal Waters of SE Alaska and others from 2009-05-16 to 2010-10-08 (NODC Accession 0117502)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0117502 includes Surface underway, chemical, meteorological and physical data collected from MILLER FREEMAN in the Bering Sea, Coastal Waters of SE...

  8. 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

    ... public of this proposed action and alternatives, present issues and potential impacts, and gather public... harvest to reduce potential impacts from the groundfish fisheries on Steller sea lions and on their... Steller sea lions and fishing vessels and to reduce potential impacts on prey resources in...

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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.

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

    Science.gov (United States)

    Kokubun, N.; Yamamoto, T.,; Sato, N.; Watanuki, Y.; Will, A.; Kitaysky, A. S.; Takahashi, A.

    2015-11-01

    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.

  15. 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

  16. 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

  17. 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

  18. 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...

  19. 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...

  20. 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...

  1. 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℃.

  2. 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

  3. Accelerometers identify new behaviors and show little difference in the activity budgets of lactating northern fur seals (Callorhinus ursinus) between breeding islands and foraging habitats in the eastern Bering Sea.

    Science.gov (United States)

    Battaile, Brian C; Sakamoto, Kentaro Q; Nordstrom, Chad A; Rosen, David A S; Trites, Andrew W

    2015-01-01

    We tagged 82 lactating northern fur seals (Callorhinus ursinus) with tri-axial accelerometers and magnetometers on two eastern Bering Sea islands (Bogoslof and St. Paul) with contrasting population trajectories. Using depth data, accelerometer data and spectral analysis we classified time spent diving (30%), resting (~7%), shaking and grooming their pelage (9%), swimming in the prone position (~10%) and two types of previously undocumented rolling behavior (29%), with the remaining time (~15%) unspecified. The reason for the extensive rolling behavior is not known. We ground-truthed the accelerometry signals for shaking and grooming and rolling behaviors--and identified the acceleration signal for porpoising--by filming tagged northern fur seals in captivity. Speeds from GPS interpolated data indicated that animals traveled fastest while in the prone position, suggesting that this behavior is indicative of destination-based swimming. Very little difference was found in the percentages of time spent in the categorical behaviors with respect to breeding islands (Bogoslof or St. Paul Island), forager type (cathemeral or nocturnal), and the region where the animals foraged (primarily on-shelf 200 m). The lack of significant differences between islands, regions and forager type may indicate that behaviors summarized over a trip are somewhat hardwired even though foraging trip length and when and where animals dive are known to vary with island, forager type and region. PMID:25807552

  4. 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...

  5. 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.

  6. The Bering Autonomous Target Detection

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Denver, Troelz; Betto, Maurizio;

    2003-01-01

    telescopes. The method has proven robust in operation and is well suited for use onboard spacecraft. As development target for the method and the associated instrumentation the asteroid research mission Bering has been used. Onboard a spacecraft, the autonomous detection is centered around the fully...

  7. Physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201511S in the Arctic Ocean, Beaufort Sea and Bering Sea from 2015-08-23 to 2015-09-26 (NCEI Accession 0145965)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0145965 includes physical, profile and underway data collected aboard the Sikuliaq during cruise SKQ201511S in the Arctic Ocean, Beaufort Sea and...

  8. 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...

  9. The Bering Target Tracking Instrumentation

    OpenAIRE

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

    2003-01-01

    The key science instrument on the Bering satellite mission is a relative small telescope with an entrance aperture of 300 mm and a focal length between 500 and 1000 mm. The detection of potential targets is performed by one of the target scanning advanced stellar compasses (ASCs). This procedure results in a simple prioritized list of right ascension, declination, proper motion and intensity of each prospective target. The telescope itself has a dedicated ASC Camera Head Unit (CHU) mounted on...

  10. 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...

  11. 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...

  12. Synoptic Drivers of Bering Strait Wave States, Fall 2011

    Science.gov (United States)

    Atkinson, D. E.

    2011-12-01

    The Bering Strait region of western Alaska, as the single point of entry to the Arctic from the Pacific, represents an important focal point of activity that ranges from heavy transport operations, such bulk ore carriers as to Teck Alaska Red Dog mine, to Arctic tourism activities, and subsistence fishing and hunting carried out by local residents. Much of that activity is set to increase in the coming years as sea ice continues to recede, allowing greater access to transport and resources in the Arctic Ocean and its marginal seas. The presence of annual sea ice cover has greatly limited the deployment of marine monitoring systems, especially wave measurement buoys. This is problematic because it limits the direct linkage of wave states to their specific synoptic drivers. To begin to address this shortcoming a buoy was deployed just south of the Bering Strait in late July with anticipated pickup in mid October, 2011. Wave events recorded by buoy, which was sponsored by the Environmental Protection Agency and NOAA, will be examined in terms of the specific synoptic systems responsible. The broader context of how typical these storm systems are will also be overviewed.

  13. 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...

  14. 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,...

  15. 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...

  16. 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

  17. 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

  18. 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,...

  19. Diatom, silicoflagellate and ebridian biostratigraphy and paleoceanography in IODP 323 Hole U1343E at the Bering slope site

    Science.gov (United States)

    Teraishi, A.; Suto, I.; Onodera, J.; Takahashi, K.

    2016-03-01

    Integrated Ocean Drilling Program (IODP) Expedition 323 was dedicated to reconstruct the details of the Pliocene-Pleistocene paleoenvironmental conditions of the Bering Sea. In this study, fossil diatom assemblages from Hole U1343E were investigated to define diatom biostratigraphy and reveal paleoceanography of the Bering slope region throughout Pleistocene. As the results, four diatom zones with Neogene North Pacific Diatom zone codes (NPD) were determined from the Neodenticula seminae Zone (NPD 12) to the N. koizumii Zone (NPD 9). Diatom biohorizons defined in this study closely correspond with onboard data, but the distinct difference is recognized at the top of the N. koizumii. Additional four biostratigraphic zones estimated by three silicoflagellate and one ebridian datums suggest the core sediment age younger than 2.5 Ma. The fluctuations of several paleoenvironmental diatom indicators show that cold conditions with sea-ice existed throughout the duration of the interval studied as well as sea ice expansion occurred at ca. 1.9 Ma and ca. 0.9 Ma. Moreover, increases of neritic diatom species reveal a drop in sea level. Neodenticula seminae is the diatom tracer of the Aleutian Current and hence the decrease of this taxon suggests decrease in inflow of the North Pacific water mass. Although the sea levels must have been dropped during the cold time interval, the consistent occurrences of N. seminae indicate that the surface water circulation in the Bering Sea was significantly influenced by the Alaskan Stream at ca. 1.9 Ma. On the other hand, during the other cooling event at ca. 0.9 Ma, which corresponds to the mid-Pleistocene transition (MPT) event, an increase of neritic diatom species and decrease of N. seminae were observed. This suggests that coastal environmental conditions accompanied the sea level drop and that the inflow from the North Pacific was weakened. The increases of sea-ice and neritic diatom species suggest that the sea ice and coastal

  20. 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...

  1. Seismic stratigraphy of the Bering Trough, Gulf of Alaska: Late Quaternary history of Bering Glacier dynamics

    Science.gov (United States)

    Montelli, A.; Gulick, S. P. S.; Worthington, L. L.; Mix, A. C.; Zellers, S.; Jaeger, J. M.

    2014-12-01

    Sedimentary architecture of the cross-shelf Bering Trough is studied using 5 high resolution seismic profiles integrated with the drilling data acquired during Integrated Ocean Drilling Program (IODP) Expedition 341. The objectives of this work are to constrain the number of advance-retreat cycles that have occurred through the Late Quaternary, examine the impact of the Bering Glacier on the continental shelf and slope, and reconstruct Bering Glacier dynamics. By tying these sequences with δ18O stratigraphy, we can test the Bering Glacier's relation to global ice sheet evolution and better understand the degree to which the glacial advance-retreat cycles were in phase with global events. Our results show that: (1) Identification of erosional surfaces and glacigenic landforms that record positions of stillstand events and diagnose the style of retreat allow us to distinguish nine phases of glacial advances and subsequent retreats. (2) Mapping shows that glacier pathways and flow directions through time are influenced by the occurrence of thick grounding-zone deposits and shifting foci of erosion. (3) Continuous buildup of glacigenic sediment fills tectonically created accommodation space and allows the glacier to advance seaward for the last three advances. Discovery of systematic, prominent deposition of glacial diamict and ice-rafted debris (IRD) during phases of glacial retreat is supported by the drilling data and suggests reconsideration of IRD impact on slope sedimentation. (4) The trough mouth fan started its development during marine isotope stage (MIS) 6, progressively advancing to the position of present shelf edge during the subsequent MIS 4 and MIS 2 and is recognized by evidence of extensive deposition of glacigenic debris flows on the slope. (5) Sedimentation rates in the depocenter are exceptionally high and are estimated to be 1-2 m/k.y. through the middle Pleistocene on the shelf and 4-5 m/k.y. average through MIS 6 on the slope.

  2. 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...

  3. 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...

  4. 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....

  5. 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.

  6. Last Deglacial Arctic to Pacific Transgressions via the Bering Strait: Implications for Climate, Meltwater Source, Ecosystems and Southern Ocean Wind Strength

    Science.gov (United States)

    Nwaodua, Emmanuel C.

    The main goal of this research is to provide physical evidence of reverse flow(s), from the Arctic to the North Pacific Ocean, after the Last Glacial Maximum (LGM). This is primarily essential to studies concerned with understanding how the fluctuations in strength of the Southern Ocean Wind (SOW), in conjunction with an open Bering Strait, alter the direction of water flow through the Bering Strait. Visible and Near Infrared (VNIR) derivative spectroscopy; quotient normalization and varimax rotated principal component analysis of diffuse spectral reflectance (DSR) measurements from 234 surface core samples and 2 piston cores, in addition to the USGS spectral library, were used to extract and identify these lithological compositions (in order of importance) within the study location. These compositions are chlorite + muscovite; goethite + phycoerythrin + phycocyanin; smectite; calcite+dolomite; and illite + Chlorophyll a. The Geostatistical tool, kriging, was utilized in creating the sedimentary maps of all the components. These maps were used to determine these components' modern spatial patterns. This aided in the evaluation and downcore interpretation of the component most suited for this study. The illite in illite + Chlorophyll a assemblage was deemed to be the appropriate water mass tracer for a reverse flow from the Arctic into the North Pacific; this is because of its prominence and abundance in the Mackenzie River drainage basin and on the west Arctic Sea shelf. The illite denotes these periods of meltwater pulses (MWP): MWP 1A, ˜14,600 and 13,800 Cal yrs. BP, separated by the Older Dryas; MWP 1B, ˜11,000--9,200 Cal yrs. BP; and MWP 1C, ˜8,000 Cal yrs. BP. The timing of these pulses along with previously published data on the Bering Sea shelf and the North Pacific Ocean enabled these deductions: 1) the initial opening of the Bering Strait and the flow direction after the LGM; 2) the source of these meltwater pulses and the mechanism that might drive

  7. 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...

  8. 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...

  9. 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.

  10. 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.

  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. 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.

  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. A Newly Recorded Sea Cucumber (Holothuroidea: Aspidochirotida: Synallactidae from East Sea, Korea

    Directory of Open Access Journals (Sweden)

    Lee, Taekjun

    2014-04-01

    Full Text Available Five sea cucumbers were collected from Gisamun and Gonghyeonjin of Gangwon-do, in the East Sea, Korea from 27 December 2009 to 14 November 2012. These specimens were classified as Synallactes nozawai Mitsukuri, 1912 belonging to the family Synallactidae of order Aspidochirotida based on morphological characteristics. The family, genus and species are recorded for the first time from Korea. The distinct morphological characteristics of this species are as follows: body flexible, with thin gelatinous body wall; presence of numerous tubercles along dorsal ambulacra table of body wall consisted of three- or four-armed disk and a spire-form pillar. This species usually inhabits the deep sea and is distributed in the Northwest Pacific from northern Japan to Bering Sea.

  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, 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...

  1. 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...

  2. 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...

  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: 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...

  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. AFSC/RACE/SAP/Armistead: 1975 - 2014 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...

  7. Avian cholera causes marine bird mortality in the Bering Sea of Alaska

    Science.gov (United States)

    Bodenstein, Barbara; Kimberlee Beckmen; Gay Sheffield; Kathy Kuletz; Van Hemert, Caroline R.; Berlowski-Zier, Brenda M.; Shearn-Bochsler, Valerie I.

    2015-01-01

    The first known avian cholera outbreak among wild birds in Alaska occurred during November 2013. Liver, intestinal, and splenic necrosis consistent with avian cholera was noted, and Pasteurella multocida serotype 1 was isolated from liver and lung or spleen in Crested Auklets (Aethia cristatella), Thick-billed Murres (Uria lomvia), Common Eider (Somateria mollissima), Northern Fulmars (Fulmarus glacialis), and Glaucous-winged Gulls (Larus glaucescens).

  8. 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...

  9. 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...

  10. AFSC/RACE/MACE: Results of 2006 Pollock Acoustic-Trawl Survey Bering Sea- DY0606

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Alaska Fisheries Science Center’s (AFSC) Midwater Assessment and Conservation Engineering (MACE) Program conduct biennial echo...

  11. 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...

  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. H07950: NOS Hydrographic Survey , Bering Sea, Alaska, 1951-09-12

    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...

  14. 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...

  15. 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...

  16. A post-cromerian rise in sea level

    International Nuclear Information System (INIS)

    The intensified cooling in the northern hemisphere during the Elsterian-Saalian ice ages (isotopic stages 22-6) resulted in a reduction of the Antarctic ice sheet by 10-15 x 106 km3, equal to a rise in sea level by about 40 m. This rise in sea level changed the hydrography of the Black Sea during the late Pleistocene warmer times, caused anoxic conditions in the eastern Mediterranean during the corresponding warming-up phases, and enhanced water transport of less saline water from the Pacific into the Arctic Ocean (the present sill depth of the Bering Strait is about 50 m). The increased supply of less saline water strengthened the halocline in the Arctic Ocean, increasing the sea ice there and, by higher albedo, its cooling effect on the adjacent continents

  17. 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...

  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. 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

  20. A tale of two seas: Reservoir age correction values (R, ΔR) for the Sakhalin Island (Sea of Japan and Okhotsk Sea)

    International Nuclear Information System (INIS)

    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

  1. 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

  2. Physical, biological and optical oceanographic data collected from moored buoys in the Bering Strait from 08/16/2004 to 09/03/2007 (NODC Accession 0045300)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, current meter, biological, and optical oceanographic data were collected in the Bering Strait from August 16, 2004 to September 3, 2007. These data were...

  3. 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...

  4. 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...

  5. 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.

  6. Melt water input from the Bering Glacier watershed into the Gulf of Alaska

    Science.gov (United States)

    Josberger, Edward G.; Shuchman, Robert A.; Jenkins, Liza K.; Arthur Endsley, K.

    2014-02-01

    The annual runoff from the melting of large glaciers and snow fields along the northern perimeter of the Gulf of Alaska is a critical component of marine physical and biological systems; yet, most of this freshwater is not measured. Here we show estimates of melt for the watershed that contains the largest and longest glacier in North America, the Bering Glacier. The procedure combines in situ observations of snow and ice melt acquired by a long-term monitoring program, multispectral satellite observations, and nearby temperature measurements. The estimated melt is 40 km3 per melt season, ± 3.0 km3, observed over the decadal period, 2002-2012. As a result of climate change, these estimates could increase to 60 km3/yr by 2050. This technique and the derived melt coefficients can be applied to estimate melt from Alaska to Washington glaciers.

  7. 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.

  8. 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....

  9. AFSC/RACE/EcoFOCI: 2011 Spring Bering Sea Mooring Cruise DY11-01/1DY11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Oscar Dyson departed Kodiak at 1300 hours on Sunday May 15th. On the way out of the bay training operations for a medical evacuation were conducted with a U.S....

  10. Synergistic effects of pCO2 and iron availability on nutrient consumption ratio of the Bering Sea phytoplankton community

    OpenAIRE

    Sugie, K.; Endo, H.; Suzuki, K.; Nishioka, J; Kiyosawa, H; Yoshimura, T.

    2013-01-01

    Little is known concerning the effect of CO2 on phytoplankton ecophysiological processes under nutrient and trace element-limited conditions, because most CO2 manipulation experiments have been conducted under elements-replete conditions. To investigate the effects of CO2 and iron availability on phytoplankton ecophysiology, we conducted an experiment in September 2009 using a phytoplankton community in the iron limited, high-nutrient, low-chlorophyll (HNLC) region of the Be...

  11. 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

    at water depths of 1008 to 3172 m. They are situated in the high productivity “Green Belt” region, with organic carbon burial rates typical of the high-productivity upwelling domains on western continental margins. The three sites show strong geochemical similarities. The downward sequence of...

  12. 75 FR 48298 - Groundfish Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab...

    Science.gov (United States)

    2010-08-10

    ...-information requirements contained in this proposed rule may be submitted to NMFS Alaska, Sustainable... report includes not only the weight of crab but also the weight of packaging, pallets, and glaze....

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. Occurrence and genotypic analysis of Trichinella species in Alaska marine-associated mammals of the Bering and Chukchi seas.

    Science.gov (United States)

    Seymour, J; Horstmann-Dehn, L; Rosa, C; Lopez, J A

    2014-02-24

    The zoonotic parasite Trichinella is the causative agent of trichinellosis outbreaks in the circumpolar Arctic. Subsistence communities are particularly prone to trichinellosis due to traditional meat preparation methods and regional presence of a freeze-tolerant Trichinella species (Trichinella nativa). This study is the first application of a validated artificial digestion method in determining incidence of Trichinella sp. in Alaskan mammals. Infection incidence in pinniped species (Erignathus barbatus, Eumetopias jubatus, Odobenus rosmarus divergens, and Pusa hispida) was low, with only 1/57 ringed seals infected. Polymerase Chain Reaction assays indicate T. nativa as the only species present in northern Alaska. Analysis of an archived polar bear (Ursus maritimus) muscle sample shows freeze-tolerance and longevity for T. nativa to -20°C for 10 years and short-term freeze resistance to -80°C when morphology was used to determine presence of live larvae. However, larval motility suggests 0% survival. An approach that combines artificial digestion with PCR based species identification has excellent potential for Trichinella sp. detection and identification of archived tissues. Overall, Trichinella in Alaskan mammals, particularly marine mammals of subsistence importance, appears to be a minor problem. These modern diagnostic techniques provide accurate insight into the presence of Trichinella in the Alaskan marine environment. PMID:24373515

  20. 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...

  1. 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.

  2. 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...

  3. 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),...

  4. 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...

  5. 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)....

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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... reports under the Sec. 680.6 EDR requirements. Classification Pursuant to section 304(b)(1)(A) of the.../ processor operators to report categories of information: ex vessel revenues; market lease revenues;...

  11. 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...

  12. 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

    ... capacity reduction programs, portions of which are applicable to the Reduction Plan, (50 CFR 600.1000 et... non-interim Federal License Limitation Program groundfish license issued pursuant to 50 CFR 679.4(k... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Longline catcher processor subsector...

  13. 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...

  14. 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...

  15. 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...

  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. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Early Pliocene onset of modern Nordic Seas circulation related to ocean gateway changes.

    Science.gov (United States)

    De Schepper, Stijn; Schreck, Michael; Beck, Kristina Marie; Matthiessen, Jens; Fahl, Kirsten; Mangerud, Gunn

    2015-01-01

    The globally warm climate of the early Pliocene gradually cooled from 4 million years ago, synchronous with decreasing atmospheric CO2 concentrations. In contrast, palaeoceanographic records indicate that the Nordic Seas cooled during the earliest Pliocene, before global cooling. However, a lack of knowledge regarding the precise timing of Nordic Seas cooling has limited our understanding of the governing mechanisms. Here, using marine palynology, we show that cooling in the Nordic Seas was coincident with the first trans-Arctic migration of cool-water Pacific mollusks around 4.5 million years ago, and followed by the development of a modern-like Nordic Seas surface circulation. Nordic Seas cooling precedes global cooling by 500,000 years; as such, we propose that reconfiguration of the Bering Strait and Central American Seaway triggered the development of a modern circulation in the Nordic Seas, which is essential for North Atlantic Deep Water formation and a precursor for more widespread Greenland glaciation in the late Pliocene. PMID:26507275

  6. Early Pliocene onset of modern Nordic Seas circulation related to ocean gateway changes

    Science.gov (United States)

    de Schepper, Stijn; Schreck, Michael; Beck, Kristina Marie; Matthiessen, Jens; Fahl, Kirsten; Mangerud, Gunn

    2015-10-01

    The globally warm climate of the early Pliocene gradually cooled from 4 million years ago, synchronous with decreasing atmospheric CO2 concentrations. In contrast, palaeoceanographic records indicate that the Nordic Seas cooled during the earliest Pliocene, before global cooling. However, a lack of knowledge regarding the precise timing of Nordic Seas cooling has limited our understanding of the governing mechanisms. Here, using marine palynology, we show that cooling in the Nordic Seas was coincident with the first trans-Arctic migration of cool-water Pacific mollusks around 4.5 million years ago, and followed by the development of a modern-like Nordic Seas surface circulation. Nordic Seas cooling precedes global cooling by 500,000 years; as such, we propose that reconfiguration of the Bering Strait and Central American Seaway triggered the development of a modern circulation in the Nordic Seas, which is essential for North Atlantic Deep Water formation and a precursor for more widespread Greenland glaciation in the late Pliocene.

  7. 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

  8. 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

  9. 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.

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. Sea level change

    Digital Repository Service at National Institute of Oceanography (India)

    Church, J.A.; Clark, P.U.; Cazenave, A.; Gregory, J.M.; Jevrejeva, S.; Levermann, A.; Merrifield, M.A.; Milne, G.A.; Nerem, R.S.; Nunn, P.D.; Payne, A.J.; Pfeffer, W.T.; Stammer, D.; Unnikrishnan, A.S.

    This chapter considers changes in global mean sea level, regional sea level, sea level extremes, and waves. Confidence in projections of global mean sea level rise has increased since the Fourth Assessment Report (AR4) because of the improved...

  17. 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.

  18. Sea water intrusion model of Amchitka Island, Alaska

    International Nuclear Information System (INIS)

    During the 1960s and 1970s, Amchitka Island, Alaska, was the site of three underground nuclear tests, referred to as Milrow, Long Shot and Cannikin. Amchitka Island is located in the western part of the Aleutian Island chain, Alaska. The groundwater systems affected by the three underground nuclear tests at Amchitka Island are essentially unmonitored because all of the current monitoring wells are too shallow and not appropriately placed to detect migration from the cavities. The dynamics of the island's fresh water-sea water hydrologic system will control contaminant migration from the three event cavities, with migration expected in the direction of the Bering Sea from Long shot and Cannikin and the Pacific Ocean from Milrow. The hydrogeologic setting (actively flowing groundwater system to maintain a freshwater lens) suggests a significant possibility for relatively rapid contaminant migration from these sites, but also presents an opportunity to use projected flowpaths to a monitoring advantage. The purpose of this investigation is to develop a conceptual model of the Amchitka groundwater system and to produce computer model simulations that reflect the boundary conditions and hydraulic properties of the groundwater system. The simulations will be used to assess the validity of the proposed conceptual model and highlight the uncertainties in hydraulic properties of the aquifer. The uncertainties will be quantified by sensitivity analyses on various model parameters. Within the limitations of the conceptual model and the computer simulations, conclusions will be drawn regarding potential radionuclide migration from the three underground nuclear tests

  19. Sea level trends in Southeast Asian seas

    OpenAIRE

    M. W. Strassburg; B. D. Hamlington; R. R. Leben; P. Manurung; J. Lumban Gaol; B. Nababan; Vignudelli, S.; Kim, K.-Y.

    2015-01-01

    Southeast Asian seas span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian oceans. The Southeast Asian sea regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost 2 decades. Initial comparisons of global sea level reconstructions find that 17-year sea level trends over the past 60 years exhibit good agreement with decadal variability associated...

  20. 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...

  1. 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

  2. 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.

  3. 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

  4. 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

  5. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki; Outola, Iisa; Ikäheimonen, Tarja; Mattila, Jukka; Herrmann, Jürgen; Kanisch, Günter; Osvath, Iolanda

    2011-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radi...... seawater; only the Irish Sea and the Black Sea show higher levels. In 1990, average concentrations of 137Cs in fish from the Baltic Sea were similar to those in the Irish Sea, about 4 times higher than in the Black Sea and about 30 times higher than in the Mediterranean Sea....

  6. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki; Outola, Iisa; Ikäheimonen, Tarja; Mattila, Jukka; Herrmann, Jürgen; Kanisch, Günter; Osvath, Iolanda

    2010-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radi...... seawater; only the Irish Sea and the Black Sea show higher levels. In 1990, average concentrations of 137Cs in fish from the Baltic Sea were similar to those in the Irish Sea, about 4 times higher than in the Black Sea and about 30 times higher than in the Mediterranean Sea....

  7. 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).

  8. Sea-floor gouges caused by migrating gray whales off northern California

    Science.gov (United States)

    Cacchione, D. A.; Drake, D. E.; Field, M. E.; Tate, G. B.

    1987-06-01

    Side-scan sonar records collected during March and April 1981 and 1982 off northern California contain elongate depressions whose sizes and shapes are similar to sea-floor gouges made by feeding gray whales ( Eschrichtius robustus) in the northern Bering Sea and in shallow embayments off British Columbia. The discovery of the whale gouges in the sonar records was unexpected, and supports some of the previous speculation that gray whales feed opportunistically during migration. Gouges occupy about 0.032% of the 7.6 km 2 of sea floor that was surveyed, which represents about 575 metric tons of excavated material. Although seemingly minor in amount, the total amount of bottom sediment removed from the central and northern California continental shelf by gray whale activities year after year represents macroscale biologically induced erosion and could have significant geological implications in shelf erosion and depositional schemes. This is the only published evidence of benthic feeding by gray whales along their migration route off northern California.

  9. 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.

  10. 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

  11. 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

  12. Mitochondrial genome diversity at the Bering Strait area highlights prehistoric human migrations from Siberia to northern North America.

    Science.gov (United States)

    Dryomov, Stanislav V; Nazhmidenova, Azhar M; Shalaurova, Sophia A; Morozov, Igor V; Tabarev, Andrei V; Starikovskaya, Elena B; Sukernik, Rem I

    2015-10-01

    The patterns of prehistoric migrations across the Bering Land Bridge are far from being completely understood: there still exists a significant gap in our knowledge of the population history of former Beringia. Here, through comprehensive survey of mitochondrial DNA genomes retained in 'relic' populations, the Maritime Chukchi, Siberian Eskimos, and Commander Aleuts, we explore genetic contribution of prehistoric Siberians/Asians to northwestern Native Americans. Overall, 201 complete mitochondrial sequences (52 new and 149 published) were selected in the reconstruction of trees encompassing mtDNA lineages that are restricted to Coastal Chukotka and Alaska, the Canadian Arctic, Greenland, and the Aleutian chain. Phylogeography of the resulting mtDNA genomes (mitogenomes) considerably extends the range and intrinsic diversity of haplogroups (eg, A2a, A2b, D2a, and D4b1a2a1) that emerged and diversified in postglacial central Beringia, defining independent origins of Neo-Eskimos versus Paleo-Eskimos, Aleuts, and Tlingit (Na-Dene). Specifically, Neo-Eskimos, ancestral to modern Inuit, not only appear to be of the High Arctic origin but also to harbor Altai/Sayan-related ancestry. The occurrence of the haplogroup D2a1b haplotypes in Chukotka (Sireniki) introduces the possibility that the traces of Paleo-Eskimos have not been fully erased by spread of the Neo-Eskimos or their descendants. Our findings are consistent with the recurrent gene flow model of multiple streams of expansions to northern North America from northeastern Eurasia in late Pleistocene-early Holocene. PMID:25564040

  13. 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...

  14. 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...

  15. 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...

  16. 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.

  17. 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?

  18. 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...

  19. 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...

  20. 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.

  1. Zooplankton, salinity, and other data from the ALPHA HELIX using nets in the Bering Sea from 22 July 1999 to 14 August 1999 (NODC Accession 0000262)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton, salinity, fluorescence, and temperature data were collected from the ALPHA HELIX from July 22, 1999 to August 14, 1999. Data were submitted by...

  2. Chemical and depth data from the ALPHA HELIX using bottle casts in the Bering Sea from 1987-09-07 to 1988-06-11 (NODC Accession 0000263)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical and depth data were collected from the ALPHA HELIX from September 7, 1987 to June 11, 1988. Data were submitted by the University of Alaska - Fairbanks;...

  3. Underway meteorological, navigational, physical and time series data collected aboard the 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 the...

  4. 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...

  5. 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 (<8%) of sugar rings dispersed in a nonpolar alkyl environment. Though nonprotonated aromatic C represented the largest fraction of aromatic C in all HPOA/TPIA isolates, only a small fraction (∼5% in HPOA and 3% in TPIA) was possibly associated with dissolved black carbon. Our results imply a relatively stable portion of DOM 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.

  6. 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...

  7. 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...

  8. AFSC/NMML: Acoustics long-term passive monitoring using moored autonomous recorders in the Bering, Chukchi, and Western Beaufort Seas, 2007-2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has deployed long-term passive acoustic recorders in various locations in Alaskan waters and in the High Arctic to...

  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. 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...

  11. 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...

  12. 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...

  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. 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...

  15. 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...

  16. 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...

  17. What Happened to Gray Whales during the Pleistocene? The Ecological Impact of Sea-Level Change on Benthic Feeding Areas in the North Pacific Ocean

    Science.gov (United States)

    Pyenson, Nicholas D.; Lindberg, David R.

    2011-01-01

    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 primary feeding ground

  18. 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

  19. Waves in the seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    of wave-energy for generation of electricty. Wind while blowing over the sea surface trans- fers huge amounts of energy into the sea by imparting oscillatory motion to the surface. This includes both ki- netic and potential Chaotic sea surface; (inset) a... stimulation and excite- ment since it has much complexity and scope for further developments. The recently developed wonder-tool of mathematics, 'fractals' can also be used to model sea surfaces. Generation of waves on the sea surface is a very complex process...

  20. Sea level report

    International Nuclear Information System (INIS)

    Study of Cenozoic Era sea levels shows a continual lowering of sea level through the Tertiary Period. This overall drop in sea level accompanied the Pleistocene Epoch glacio-eustatic fluctuations. The considerable change of Pleistocene Epoch sea level is most directly attributable to the glacio-eustatic factor, with a time span of 105 years and an amplitude or range of approximately 200 m. The lowering of sea level since the end of the Cretaceous Period is attributed to subsidence and mid-ocean ridges. The maximum rate for sea level change is 4 cm/y. At present, mean sea level is rising at about 3 to 4 mm/y. Glacio-eustacy and tectono-eustacy are the parameters for predicting sea level changes in the next 1 my. Glacio-eustatic sea level changes may be projected on the basis of the Milankovitch Theory. Predictions about tectono-eustatic sea level changes, however, involve predictions about future tectonic activity and are therefore somewhat difficult to make. Coastal erosion and sedimentation are affected by changes in sea level. Erosion rates for soft sediments may be as much as 50 m/y. The maximum sedimentation accumulation rate is 20 m/100 y

  1. Sea level extremes in the Caribbean Sea

    OpenAIRE

    Torres, R. Ricardo; Tsimplis, Michael N.

    2014-01-01

    Sea level extremes in the Caribbean Sea are analyzed on the basis of hourly records from 13 tide gauges. The largest sea level extreme observed is 83 cm at Port Spain. The largest nontidal residual in the records is 76 cm, forced by a category 5 hurricane. Storm surges in the Caribbean are primarily caused by tropical storms and stationary cold fronts intruding the basin. However, the seasonal signal and mesoscale eddies also contribute to the creation of extremes. The five stations that have...

  2. 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 ...

  3. 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...

  4. 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),...

  5. 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...

  6. 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....

  7. 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.

  8. Water mass characteristics and their temporal changes in a biological hotspot in the southern Chukchi Sea

    Science.gov (United States)

    Nishino, S.; Kikuchi, T.; Fujiwara, A.; Hirawake, T.; Aoyama, M.

    2015-10-01

    We analysed mooring and ship-based hydrographic and biogeochemical data obtained from a Hope Valley biological hotspot in the southern Chukchi Sea. The moorings were deployed from 16 July 2012 to 19 July 2014, and data were captured during spring and fall blooms with high chlorophyll a concentrations. Turbidity increased and dissolved oxygen decreased in the bottom water at the mooring site before the fall bloom, suggesting an accumulation of particulate organic matter and its decomposition (nutrient regeneration) at the bottom. This event may have been a trigger for the fall bloom at this site. The bloom was maintained for 1 month in 2012 and for 2 months in 2013. The maintenance mechanism for the fall bloom was also studied by hydrographic and biogeochemical surveys in late summer to fall 2012 and 2013. Nutrient-rich water from the Bering Sea supplied nutrients to Hope Valley, although a reduction in nutrients may have occurred in 2012 by mixing of lower-nutrient water that would have remained on the Chukchi Sea shelf during the spring and fall blooms. In addition, nutrient regeneration at the bottom of Hope Valley could have increased nutrient concentrations and explained 60 % of its nutrient content in fall 2012. The high nutrient content with the dome-like structure of the bottom water may have maintained the high primary productivity at this site during the fall bloom. Primary productivity was 0.3 in September 2012 and 1.6 g C m-2 d-1 in September 2013. The lower productivity in 2012 was related to strong stratification caused by the high fraction of surface sea ice meltwater.

  9. 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

  10. 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

  11. 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

  12. 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)...

  13. Oceanography of marginal seas

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    . The Andaman Sea remains the least studied basin in this region. Physical and chemical signatures suggest that the deep basin of the Andaman Sea are largely influenced by intermediate circulation. Deep waters are warmer and low in oxygen than those at similar...

  14. SEA and planning

    DEFF Research Database (Denmark)

    Stoeglehner, G.; Brown, A.L.; Kørnøv, Lone

    2009-01-01

    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...

  15. Dilemmas in SEA application

    DEFF Research Database (Denmark)

    Lyhne, Ivar

    Dilemmas in SEA Application: The DK Energy SectorIvar Lyhne - lyhne@plan.aau.dk. Based on three years of collaborative research, this paper outlines dilemmas in the application of SEA in the strategic development of the Danish energy sector. The dilemmas are based on concrete examples from practice...

  16. Motorways of the Sea

    OpenAIRE

    Ionita Profir

    2011-01-01

    In its communication aim, the European Commission presents the following definition: short distance shipping means the movement of cargo and passengers by sea between ports situated in Europe geographical area or between those ports and ports situated in non-European countries located at closed seas on the border of Europe

  17. North Sea update

    International Nuclear Information System (INIS)

    The article deals with the offshore activity in the North Sea bringing together a special update feature for the petroleum industries in the United Kingdom, Norway, Denmark and the Netherlands. The total capital expenditure required for the period from 1995 to 1998 for the North Sea area which includes exploration, development projects and well abandoning, are discussed and presented. 20 figs., 5 tabs

  18. 76 FR 23996 - North Pacific Fishery Management Council Public Meeting

    Science.gov (United States)

    2011-04-29

    ... area boundary; review report on Northern Bering Sea Research Plan. 5. Gulf of Alaska (GOA) Salmon Issues: Final action of GOA Chinook Salmon Bycatch Pollock fishery. 6. Bering Sea Aleutian Island...

  19. IOMASA SEA ICE DEVELOPMENTS

    DEFF Research Database (Denmark)

    Andersen, Søren; Tonboe, Rasmus; Heygster, Georg; Melsheimer, Christian; Pedersen, Leif Toudal; Schyberg, Harald; Tveter, Frank; Dahlgren, Per; Lundelius, Tomas; Gustafsson, Nils

    2005-01-01

    Sensitivity studies show that the radiometer ice concentration estimate can be biased by +10% by anomalous atmospheric emissivity and -20% by anomalous ice surface emissivity. The aim of the sea ice activities in EU 5th FP project IOMASA is to improve sea ice concentration estimates at higher...... spatial resolution. The project is in the process of facilitating an ice concentration observing system through validation and a better understanding of the microwave radiative transfer of the sea ice and overlying snow layers. By use of a novel modelling approach, it is possible to better detect and...... determine the circumstances that may lead to anomalous sea ice concentration retrieval as well as to assess and possibly minimize the sensitivities of the retrieval system. Through an active partnership with the SAF on Ocean and Sea Ice, a prototype system will be implemented as an experimental product...

  20. Biogeochemical analysis of ancient Pacific Cod bone suggests Hg bioaccumulation was linked to paleo sea level rise and climate change

    Directory of Open Access Journals (Sweden)

    Maribeth S. Murray

    2015-02-01

    Full Text Available Deglaciation at the end of the Pleistocene initiated major changes in ocean circulation and distribution. Within a brief geological time, large areas of land were inundated by sea-level rise and today global sea level is 120 m above its minimum stand during the last glacial maximum. This was the era of modern sea shelf formation; climate change caused coastal plain flooding and created broad continental shelves with innumerable consequences to marine and terrestrial ecosystems and human populations. In Alaska, the Bering Sea nearly doubled in size and stretches of coastline to the south were flooded, with regional variability in the timing and extent of submergence. Here we suggest how past climate change and coastal flooding are linked to mercury bioaccumulation that could have had profound impacts on past human populations and that, under conditions of continued climate warming, may have future impacts. Biogeochemical analysis of total mercury (tHg and 13C/15N ratios in the bone collagen of archaeologically recovered Pacific Cod (Gadus macrocephalus bone shows high levels of tHg during early/mid-Holocene. This pattern cannot be linked to anthropogenic activity or to food web trophic changes, but may result from natural phenomena such as increases in productivity, carbon supply and coastal flooding driven by glacial melting and sea-level rise. The coastal flooding could have led to increased methylation of Hg in newly submerged terrestrial land and vegetation. Methylmercury is bioaccumulated through aquatic food webs with attendant consequences for the health of fish and their consumers, including people. This is the first study of tHg levels in a marine species from the Gulf of Alaska to provide a time series spanning nearly the entire Holocene and we propose that past coastal flooding resulting from climate change had the potential to input significant quantities of Hg into marine food webs and subsequently to human consumers.

  1. Productivity, chlorophyll a, Photosynthetically Active Radiation (PAR) and other phytoplankton data from the Arctic Ocean, Bering Sea, Chukchi Sea, Beaufort Sea, East Siberian Sea, Kara Sea, Barents Sea, and Arctic Archipelago measured between 17 April, 1954 and 30 May, 2006 compiled as part of the Arctic System Science Primary Production (ARCSS-PP) observational synthesis project (NODC Accession 0063065)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Arctic Ocean primary production data were assembled from original input data archived in various international databases, provided by individual investigators or in...

  2. The offshore northeastern Chukchi Sea, Alaska: A complex high-latitude ecosystem

    Science.gov (United States)

    Day, Robert H.; Weingartner, Thomas J.; Hopcroft, Russell R.; Aerts, Lisanne A. M.; Blanchard, Arny L.; Gall, Adrian E.; Gallaway, Benny J.; Hannay, David E.; Holladay, Brenda A.; Mathis, Jeremy T.; Norcross, Brenda L.; Questel, Jennifer M.; Wisdom, Sheyna S.

    2013-09-01

    We conducted an interdisciplinary ecological study in and near 3 nearby proposed exploratory oil and gas prospects in the offshore northeastern Chukchi Sea during the open-water seasons of 2008-2010. This region exhibits a classical pelagic-benthic dichotomy of food-web structure in ecological function. The Klondike study area borders the eastern edge of the Central Channel and functions as a pelagic-dominated ecosystem, whereas the Burger study area lies south of Hanna Shoal and functions as a benthic-dominated ecosystem. The Statoil study area, which is located north of Klondike and northwest of Burger, has both pelagic and benthic attributes, although it is more like Burger than like Klondike. Klondike has lower benthic density and biomass, a higher biomass of oceanic zooplankton, and more fishes and planktivorous seabirds than does Burger, which has benthic communities with high density and biomass, primarily neritic zooplankton, and higher densities of benthic-feeding marine mammals than Klondike; Statoil has characteristics of both ecosystems. Patterns of sea-ice retreat vary interannually; in some years, much of the northeastern Chukchi is ice-free by mid-May, leading to pelagic and ice-edge phytoplankton blooms, whereas heavy ice cover in other years leads to substantial within-ice production. The characteristics of this region during the open-water season are not consistent among years, in that Bering Sea Water impinges onto all study areas only in some years, resulting in interannual variation in the distribution and abundance of zooplankton, planktivorous seabirds, and pelagic-feeding seals. These interannual variations alter several aspects of this pelagic-benthic dichotomy, and some aspects of this region suggest unusual structure (e.g., replacement of benthic-feeding fishes in some areas by predatory invertebrates, a lack of benthic-feeding seaducks).

  3. Intermittent Sea Level Acceleration

    OpenAIRE

    Olivieri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Spada, G.; Dipartimento di Scienze di Base e Fondamenti, Università di Urbino Carlo Bo, Urbino

    2013-01-01

    Using instrumental observations from the Permanent Service for Mean Sea Level (PSMSL), we provide a new assessment of the global sea{level acceleration for the last 2 centuries (1820-2010). Our results, obtained by a stack of tide gauge time series, con firm the existence of a global sea level acceleration (GSLA) and, coherently with independent assessments so far, they point to a value close to 0:01 mm/yr2. However, di fferently from previous studies, we discuss how change points or ...

  4. Changes in Sea Level

    OpenAIRE

    Church, J.A.; Gregory, J. M.; Huybrechts, Philippe; Kuhn, M.; Lambeck, K.; Nhuan, M. T.; Qin, D.; Woodworth, P. L.

    2001-01-01

    This chapter assesses the current state of knowledge of the rate of change of global-averaged and regional sea-level in relation to climate change. We focus on the 20th and 21st centuries.However, because of the slow response to past conditions of the oceans and ice sheets and the consequent land movements, we consider changes in sea level prior to the historical record, andwe also look over a thousand years into the future.Past changes in sea levelFrom recent analyses, our conclusions are as...

  5. Caspian sea: petroleum challenges

    International Nuclear Information System (INIS)

    The Caspian sea is one of the world areas the most promising in terms of investments and petroleum development. This study presents the petroleum challenges generated by this hydrocarbons reserve. The first part discusses the juridical status (sea or lake), the petroleum and the gas reserves, the ecosystem and the today environment (fishing and caviar), the geostrategic situation and the transport of gas and oil. It provides also a chronology from 1729 to 2005, a selection of Internet sites, books and reports on the subject and identity sheets of the countries around the Caspian sea. (A.L.B.)

  6. Sea Scallop Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Sea Scallop Survey began in 1980 and has covered an area from Cape Hatteras to Georges Bank. The survey aims to determine the distribution...

  7. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki;

    2011-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s....... Radioactivity inputs into the Baltic Sea from nuclear reprocessing plants in Western Europe have become of minor importance due to significant reduction of discharges in recent years. In terms of input of 137Cs into the Baltic Sea, Chernobyl fallout has contributed about 82% and nuclear weapons test fallout...... about 14%. For 90Sr in the Baltic Sea, input from atmospheric fallout from nuclear weapons tests has contributed about 81%, while the contribution from Chernobyl fallout was about 13%. Cesium-137 is the main indicator of Baltic seawater with respect to anthropogenic radioactivity. The highest...

  8. South China Sea

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chinese Foreign Minister Yang Jiechi warned against attempts to "in-ternationalize" the issue of the South China Sea, where China has territorial disputes with some ASEAN member states, including Viet Nam and the

  9. Black Sea aerosols

    International Nuclear Information System (INIS)

    Shipboard, high volume air particulate samples were collected from the Black Sea atmosphere and analyzed by instrumental neutron activation analysis, atomic absorption spectrophotometry and ion chromatography for about 40 elements and ions. Concentrations of elements in the eastern and western parts of the Black Sea are different at the 95% confidence level, with lower concentrations in the eastern Black Sea. Back-trajectories and concentrations of elements in trajectory groups show that Europe accounts for more than 70% of the anthropogenic elements in the atmosphere. The average sulfate concentration was 7 μg/m3, which is comparable with rural sulfate levels in western Europe. Fluxes of elements from the atmosphere to the Black Sea are in good agreement with the results of similar flux calculations for other regions

  10. Mediterranean sea level variations.

    Science.gov (United States)

    Vigo, I.; Sánchez Reales, J. M.; García, D.; Chao, B. F.

    2009-04-01

    In this work we report an updated study of the sea level variations for the Mediterranean sea for the period from October 1992 to January 2008. The study addresses two mayor issues: (i)The analysis of the spatial and temporal variability of sea surface height (SSH) from radar altimetry measurements (from TOPEX/Poseidon (T/P) + Jason-1, etc.). We use EOF analysis to explain most of its interannual variation, and how the different basins interact. (ii) The analysis of dynamics and balance of water mass transport for the whole period. We estimate the steric SSH by combining the steric SSH estimated from temperature and salt profiles simulated by the ECCO model with time-variable gravity (TVG) data (from GRACE) for the Mediterranean Sea. The estimated steric SSH together with the SSH obtained from altimetry allow for a more realistic estimation of the water mass variations in the Mediterranean for the whole period.

  11. ROE Sea Level Relative

    Data.gov (United States)

    U.S. Environmental Protection Agency — This point dataset represents changes in relative sea level along U.S. coasts, 1960-2013. Data were provided by the National Oceanic and Atmospheric Administration...

  12. Pollution of coastal seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    cities. Various types of wastes, if not properly treated, would cause serious pollution of these shallow seas endangering marine life and spoiling recreational facilities. Different polluting agents like sewage, chemicals, industrial coolants etc...

  13. South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Morton, Brian [Hong Kong Univ., Swire Inst. of Marine Science, Hong Kong (China); Hong Kong Univ., Dept. of Ecology and Biodiversity, Hong Kong (China); Blackmore, Graham [Hong Kong Univ. of Science and Technology, Dept. of Biology, Hong Kong (China)

    2001-07-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshops and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km{sup 2} and depths range from the shallowest coastal fringe to 5377m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economics on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken

  14. Understanding sea level changes

    OpenAIRE

    Chao, BF; Farr, T.; Labrecque, J; Bindschadler, R.; Douglas, B; E. Rignot; Shum, CK; Wahr, J.

    2002-01-01

    Sea level change occurs on all timescales, depending on the type of change in question. It also occurs with a continuous range of spatial scales-local, regional, and global. To understand and be able to eventually predict sea level changes is a truly interdisciplinary endeavor. It requires geodetic and non-geodetic measurements of various types from space as well as in situ, while various numerical models for a number of meteorological and geophysical processes or properties are essential or ...

  15. Canterbury Basin Sea Level

    OpenAIRE

    Fulthorpe, C. S.; Institute for Geophysics John A. and Katherine G. Jackson School of Geosciences The University of Texas at Austin J.J. Pickle Research Campus, Building 196 (ROC) 10100 Burnet Road (R2200) Austin TX 78758-4445 USA; Hoyanagi, K.; Department of Geology Faculty of Science Shinshu University 3-1-1 Asahi, Matsumoto 390-8621 Japan; Blum, P.; United States Implementing Organization Integrated Ocean Drilling Program Texas A&M University 1000 Discovery Drive College Station TX 77845 USA; Guèrin, G.; Borehole Research Group Lamont-Doherty Earth Observatory of Columbia University PO Box 1000, 61 Route 9W Palisades NY 10964 USA; Slagle, A. L.; Borehole Research Group Lamont-Doherty Earth Observatory of Columbia University PO Box 1000, 61 Route 9W Palisades NY 10964 USA; Blair, S. A.; Department of Geological Sciences Florida State University 006 Carraway Building Tallahassee FL 32306 USA; Browne, G. H.; Hydrocarbon Section GNS Science PO Box 30368 Lower Hutt New Zealand; Carter, R. M.; Marine Geophysical Laboratory James Cook University of North Queensland Townsville QLD 4811 Australia; Ciobanu, M.; Laboratoire de Microbiologie des Environnements Extrêmes CNRS UMR-6197 Institut Universitaire Européen de la Mer Technopole Brest-Iroise Plouzane 29280 France; Claypool, G. E.; Organic Geochemist 8910 West 2nd Avenue Lakewood CO 80226 USA; Crundwell, M. P.; New Zealand Observer/Paleontologist (foraminifers) Paleontology and Environmental Change Section GNS Science PO Box 30368 Lower Hutt New Zealand; Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Ding, X.; School of Marine Sciences China University of Geosciences (Beijing) 29 XueYuan Road, Haidian District Beijing P.R. China; George, S. C.; Department of Earth and Planetary Sciences Macquarie University Sydney NSW 2109 Australia; Hepp, D. A.; MARUM – Center for Marine Environmental Sciences and Department of Geosciences University of Bremen Leobener Strasse MARUM Building, Room 2230 28359 Bremen Germany

    2010-01-01

    Integrated Ocean Drilling Program (IODP) Expedition 317 was devoted to understanding the relative importance of global sea level (eustasy) versus local tectonic and sedimentary processes in controlling continental margin sedimentary cycles. The expedition recovered sediments from the Eocene to recent period, with a particular focus on the sequence stratigraphy of the late Miocene to recent, when global sea level change was dominated by glacioeustasy. Drilling in the Canterbury Basin,...

  16. Aerial surveys of endangered whales in the Alaskan Chukchi and western Beaufort Seas, 1990. Final report, Oct-Nov 90

    International Nuclear Information System (INIS)

    In keeping with the National Environmental Policy Act (1969), the Marine Mammal Protection Act (1972) and the Endangered Species Act (1973), the OCS Lands Act Amendments (1978) established a management policy that included studies in OCS lease sale areas to ascertain potential environmental impacts of oil and gas development on OCS marine coastal environments. The Minerals Management Service (MMS) is the agency responsible for these studies and for the leasing of submerged Federal lands. The report summarizes the 1990 investigations of the distribution, abundance, migration, behavior and habitat relationships of endangered whales in the Alaskan Chukchi and western Beaufort Seas (hereafter, study area); 1990 was the second of a three year (1989-91) study. The Bering Sea stock of bowhead whales (Balaena mysticetus) was the principal species studied, with incidental sightings of all other marine mammals routinely recorded. The 1990 season was compromised by circumstances that restricted the availability of the survey aircraft (Grumman Goose, model G21G) to the period 26 October - 7 November; opportunistic surveys were flown in the study area from 3-25 October. In 1990, there were 14 sightings of 19 bowheads from 9-29 October; 5 whales, including 2 calves, were seen north of the study area. One gray whale, 110 belukhas and 53 polar bears were also seen. Over nine survey seasons (1982-90), there were 240 sightings of 520 bowhead whales and 148 sightings of 398 gray whales

  17. Underway meteorological, navigational, physical and time series data collected aboard the NOAA Ship Rainier in the Beaufort Sea, Bering Sea and others from 2015-06-19 to 2015-08-27 (NCEI Accession 0130918)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0130918 contains raw underway meteorological, navigational, physical and time series data logged by the Scientific Computer System (SCS) aboard the...

  18. November Dipole Anomaly in Northern Extratropical Sea Level Pressure and its Linkage to the Preceding Wintertime Arctic Oscillation

    Science.gov (United States)

    Choi, Y. W.; Ahn, J. B.

    2015-12-01

    This paper examines the impact of the wintertime Arctic Oscillation (AO) on the following November circulation. The application of a set of statistical methods shows that a response of November sea level pressure (SLP) to the preceding wintertime AO operates on a hemispheric scale (Choi et al., 2015). At high and middle latitudes, this response is a well-pronounced seesaw in SLP between the Eastern and Western Hemispheres. Winters of the positive AO polarity tend to be followed by positive SLP anomalies spanning the whole Northern Eurasia and negative SLP anomalies extending from the Bering Sea through the Western North Atlantic. Opposite SLP anomalies prevail after winters of the negative AO polarity. The response of November SLP to the preceding wintertime AO closely resembles the first empirical orthogonal function of November SLP. That is, the polarity of the wintertime AO precedes the polarity of the leading mode of variability of November SLP over the Northern Hemisphere. The wintertime AO exerts a 9-month lag impact on November circulation due to the re-emergence of a sea surface temperature anomaly over the western North Atlantic. Acknowledgements This work was funded by the Korea Meteorological Administration Research and Development Program under grant KMIPA 2015-2081 and Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under Grant Project No. PJ009353, Republic of Korea. Reference Choi, Y.-W., J.-B. Ahn, V. N. Kryjov, 2015. November seesaw in northern extratropical sea level pressure and its linkage to the preceding wintertime Arctic Oscillation, Int. J. Climatol., DOI: 10.1002/joc.4431

  19. Limits to benthic feeding by eiders in a vital Arctic migration corridor due to localized prey and changing sea ice

    Science.gov (United States)

    Lovvorn, James R.; Rocha, Aariel R.; Jewett, Stephen C.; Dasher, Douglas; Oppel, Steffen; Powell, Abby N.

    2015-08-01

    Four species of threatened or declining eider ducks that nest in the Arctic migrate through the northeast Chukchi Sea, where anticipated industrial development may require prioritizing areas for conservation. In this nearshore corridor (10-40 m depth), the eiders' access to benthic prey during the spring is restricted to variable areas of open water within sea ice. For the most abundant species, the king eider (Somateria spectabilis), stable isotopes in blood cells, muscle, and potential prey indicate that these eiders ate mainly bivalves when traversing this corridor. Bivalves there were much smaller than the same taxa in deeper areas of the northern Bering Sea, possibly due to higher mortality rates caused by ice scour in shallow water; future decrease in seasonal duration of fast ice may increase this effect. Computer simulations suggested that if these eiders forage for >15 h/day, they can feed profitably at bivalve densities >200 m-2 regardless of water depth or availability of ice for resting. Sampling in 2010-2012 showed that large areas of profitable prey densities occurred only in certain locations throughout the migration corridor. Satellite data in April-May over 13 years (2001-2013) indicated that access to major feeding areas through sea ice in different segments of the corridor can vary from 0% to 100% between months and years. In a warming and increasingly variable climate, unpredictability of access may be enhanced by greater effects of shifting winds on unconsolidated ice. Our results indicate the importance of having a range of potential feeding areas throughout the migration corridor to ensure prey availability in all years. Spatial planning of nearshore industrial development in the Arctic, including commercial shipping, pipeline construction, and the risk of released oil, should consider these effects of high environmental variability on the adequacy of habitats targeted for conservation.

  20. The Dead Sea

    Science.gov (United States)

    2006-01-01

    The Dead Sea is the lowest point on Earth at 418 meters below sea level, and also one of the saltiest bodies of water on Earth with a salinity of about 300 parts-per-thousand (nine times greater than ocean salinity). It is located on the border between Jordan and Israel, and is fed by the Jordan River. The Dead Sea is located in the Dead Sea Rift, formed as a result of the Arabian tectonic plate moving northward away from the African Plate. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride. In the early part of the 20th century, the Dead Sea began to attract interest from chemists who deduced that the Sea was a natural deposit of potash and bromine. From the Dead Sea brine, Israel and Jordan produce 3.8 million tons potash, 200,000 tons elemental bromine, 45,000 tons caustic soda, 25, 000 tons magnesium metal, and sodium chloride. Both countries use extensive salt evaporation pans that have essentially diked the entire southern end of the Dead Sea. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining

  1. The influence of regional Arctic sea-ice decline on stratospheric and tropospheric circulation

    Science.gov (United States)

    McKenna, Christine; Bracegirdle, Thomas; Shuckburgh, Emily; Haynes, Peter

    2016-04-01

    region (one perturbation experiment combines all regions). These regions correspond to sea-ice loss hotspots such as the Barents-Kara Seas and the Bering Sea. The differences between the control and perturbation runs yields the effects of the imposed sea-ice loss on the polar vortex. To detect and count SSWs for each run, we use the World Meteorological Organisation's definition of an SSW (a reversal in zonal mean zonal wind at 10 hPa and 60° N, and a reversal in zonal mean meridional temperature gradient at 10 hPa between 60° N and 90° N). The poster will present and discuss the initial results of this study. Implications of the results for future change in the lower latitude mid-troposphere will be discussed. References Sun, L., C. Deser, and R. A. Tomas, 2015: Mechanisms of Stratospheric and Tropospheric Circulation Response to Projected Arctic Sea Ice Loss. J. Climate, 28, 7824-7845, doi: http://dx.doi.org/10.1175/JCLI-D-15-0169.1.

  2. Lost at Sea

    Institute of Scientific and Technical Information of China (English)

    Maya; Reid

    2011-01-01

    OVER the last several years,dozens of sea turtles have been washing up on the shores of Central Africa dead.Many of these creatures,olive ridley turtles,were adult females poised to breed. Most puzzling,though,is that these turtles are being found on protected beaches that belong to national parks both in Gabon and the Republic of the Congo. Olive ridleys are considered to be the most abundant sea turtles on the planet,with around 800,000 females nesting annually.They can be found around the globe,in places like China’s Hainan and Hong Kong,among others.In spite of their numbers,they are the world’s most exploited species of sea

  3. Indicators and SEA

    DEFF Research Database (Denmark)

    Gao, Jingjing; Kørnøv, Lone; Christensen, Per

    well as in communicative perspective. Developing indicators is both a political and professional process, and the paper finally discuss the need of selection criteria mentioned in the guidelines, and also gives some ideas on how to tackle the development of indicators being explicit about it both as a......Abstract: Indicators are widely used in SEA to measure, communicate and monitor impacts from a proposed policy, plan or programme, and can improve the effectiveness for the SEA by simplifying the complexity of both assessment and presentation. Indicators can be seen as part of the implementation...... process helping to understand, communicate and, integrate important environmental issues in planning and decision-making. On the other hand, use of indicators can also limit SEA effectiveness, if the ones chosen are biased or limited, if the aggregation gives incorrect interpretation and if the...

  4. Dynamics of sea level variations in the coastal Red Sea

    Science.gov (United States)

    Churchill, James; Abulnaja, Yasser; Nellayaputhenpeedika, Mohammedali; Limeburner, Richard; Lentz, Steven

    2016-04-01

    Sea level variations in the central Red Sea coastal zone span a range of roughly 1.2 m. Though relatively small, these water level changes can significantly impact the environment over the shallow reef tops prevalent in the central Red Sea, altering the water depth by a factor or two or more. While considerable scientific work has been directed at tidal and seasonal variations of Red Sea water level, very little attention has been given to elevation changes in an 'intermediate' frequency band, with periods of 2-30 d, even though motions in this band account for roughly half of the sea level variance in central Red Sea. We examined the sea level signal in this band using AVISO sea level anomaly (SLA) data, COARDAS wind data and measurements from pressure sensors maintained for more than five years at a number of locations in Saudi Arabian coastal waters. Empirical orthogonal function analysis of the SLA data indicates that longer-period (10-30 d) sea level variations in the intermediate band are dominated by coherent motions in a single mode that extends over most of the Red Sea axis. Idealized model results indicate that this large-scale mode of sea level motion is principally due to variations in the large-scale gradient of the along-axis wind. Our analysis indicates that coastal sea level motions at shorter periods (2-10 d) are principally generated by a combination of direct forcing by the local wind stress and forcing associated with large-scale wind stress gradients. However, also contributing to coastal sea level variations in the intermediate frequency band are mesoscale eddies, which are prevalent throughout the Red Sea basin, have a sea level signal of 10's of cm and produce relatively small-scale (order 50 km) changes in coastal sea level.

  5. Sea-level fluctuations and deep-sea sedimentation rates.

    Science.gov (United States)

    Worsley, T R; Davies, T A

    1979-02-01

    Sediment accumulation rate curves from 95 drilled cores from the Pacific basin and sea-level curves derived from continental margin seismic stratigraphy show that high biogenous sediment accumulation rates correspond to low eustatic sea levels for at least the last 48 million years. This relationship fits a simple model of high sea levels producing lower land/sea ratios and hence slower chemical erosion of the continents, and vice versa. PMID:17734144

  6. Seawater-derived neodymium isotope records in the Chukchi Sea, western Arctic Ocean during Holocene: implications for oceanographic circulation

    Science.gov (United States)

    Lee, Borom; Nam, Seung-Il; Huh, Youngsook; Lee, Mi Jung

    2015-04-01

    Changes in oceanographic circulation in the Artic have a large influence on the global oceanic and climate system of the Earth through the geological times. In particular, freshwater input from the North Pacific to the western Arctic Ocean affects the Atlantic meridional overturning circulation (AMOC) after the opening of the Bering Strait. Seawater-derived neodymium isotope in marine sediments has been used as a proxy to trace the origin of water masses and oceanic circulation system. The global average residence time of Nd is shorter than the global ocean mixing time and dissolved Nd in seawater behaves quasi-conservatively. In the modern Arctic Ocean, the Nd isotope distribution is dominated by Atlantic source water, although the circum-Arctic riverine discharge and Pacific-derived waters also have noticeable impacts. In this study, we investigated seawater-derived neodymium isotope records from a sediment core recovered from the Chukchi Sea to understand the changes in hydrograhic circulation of the western Arctic during the Holocene. A gravity core, ARA02B 01A, was collected on the northern shelf of the Chukchi Sea (73°37.8939'N, 166°30.9838'W, ca. 111 m in water depth) during the RV Araon expedition in 2011. To obtain seawater-derived Nd records, we extracted Fe-Mn oxide coatings as an authigenic fraction from bulk sediments by leaching with acid-reducing solution after removing carbonate by leaching with acetic acid. Our preliminary results might show a general pattern of increasing radiogenic ɛNd values through Holocene intervals. Therefore, it implies that ɛNd results may be related with variations in the intensity of Bering Strait inflow during the last ~9.31 ka BP. The radiogenic trend was strongly pronounced from the late Holocene (ɛNd -7.23; ca. 8.84 ka BP) to the middle Holocene (ɛNd -4.78; ca. 6.18 ka BP) and vaguely during the middle Holocene. After 4.13 ka BP, ɛNd values were increased again from -4.86 to -4.03 at 0.57 ka BP. But 87Sr/86Sr

  7. Skin disorders at sea.

    Science.gov (United States)

    Lucas, Ray; Boniface, Keith; Hite, Michael

    2010-01-01

    The purpose of this study is to characterize the types of skin disorders occurring at sea requiring acute treatment. The case logs of a tele-medicine service for US flagged ships at sea were reviewed from March 1, 2006 until March 1, 2009. Of 1844 total cases, 10% (n = 183) were for skin disorders. Sixty-eight percent (n = 125) were infections, 14% (n = 25) were inflammatory, 7% (n = 13) were environmental, and 11% (n = 20) were non-specific rashes. Cutaneous abscesses and cellulitis (n = 84) were the most common acute skin disorders encountered. In some cases (n = 81), still digital photographs aided in the diagnosis. PMID:20496321

  8. Seasonal Change of Steric Sea Level in the GIN Seas

    Institute of Scientific and Technical Information of China (English)

    LI Lei; WANG Huijuan; SUN Ruili

    2011-01-01

    The Greenland Sea, Iceland Sea, and Norwegian Sea (GIN seas) form the main channel connecting the Arctic Ocean with other Oceans, where significant water and energy exchange take place, and play an important role in global climate change. In this study steric sea level, associated with temperature and salinity, in the GIN seas is examined based on analysis of the monthly temperature and salinity fields from Polar science center Hydrographic Climatology (PHC3.0). A method proposed by Tabata et al. is used to calculate steric sea level, in which, steric sea level change due to thermal expansion and haline contraction is termed as the thermosteric component (TC) and the halosteric component (SC), recpectively. Total steric sea level (TSSL) change is the sum of TC and SC. The study shows that SC is making more contributions than TC to the seasonal change of TSSL in the Greenland Sea, whereas TC contributes more in the Norwegian and the Iceland Seas. Annual variation of TSSL is larger than 50ram over most regions of the GIN Seas, and can be larger than 200mm at some locations such as 308mm at 76.5°N, 12.5°E and 246mm at 77.50N, 17.5°W.

  9. SEA LEVEL (TOPEX/POSEIDON)

    Data.gov (United States)

    National Aeronautics and Space Administration — Sea level rise is caused by the thermal expansion of sea water due to climate warming and widespread melting of land ice. The TOPEX/POSEIDON mission a joint...

  10. Solomon's Sea and [Pi

    Science.gov (United States)

    Simoson, Andrew J.

    2009-01-01

    This paper is a whimsical survey of the various explanations which might account for the biblical passage in I Kings 7:23 that describes a round object--a bronze basin called Solomon's Sea--as having diameter ten cubits and circumference thirty cubits. Can the biblical pi be any number other than 3? We offer seven different perspectives on this…

  11. The Dirac Sea

    OpenAIRE

    Dimock, J.

    2010-01-01

    We give an alternate definition of the free Dirac field featuring an explicit construction of the Dirac sea. The treatment employs a semi-infinite wedge product of Hilbert spaces. We also show that the construction is equivalent to the standard Fock space construction.

  12. Solar Sea Power

    Science.gov (United States)

    Zener, Clarence

    1976-01-01

    In their preoccupation with highly complex new energy systems, scientists and statesmen may be overlooking the possibilities of Ocean Thermal Energy Conversion (OTEC). That is the view of a Carnegie-Mellon University physicist who is in the forefront of solar sea power investigation. (Author/BT)

  13. The Provident Sea

    Science.gov (United States)

    Cushing, David H.

    1988-09-01

    The Provident Sea describes the history of fish stock management (including whales and seals). The book traces, on the basis of the original scientific material, the history of the management of "the provident sea" up to recent times when problems of over-exploitation have had dramatic effects upon stocks. The need for management arose mainly from the increasing industrialization of capture. Hence the preindustrial fisheries are covered, in particular the old cod fishery on the Grand Bank and the herring fishery in the North Sea, as an essential background to current problems. The origins of fisheries and whaling science are described, as is the development up to 1965 of the science and institution in fisheries, whaling, and sealing. In the sixties and seventies, certain major fishing nations took a heavy harvest of fish stocks using sophisticated and efficient gathering methods. This in turn led to conflict and one consequence was the "Law of the Sea" conference set up to try and resolve these issues.

  14. Pollution around Malta's sea

    OpenAIRE

    Formosa, Nicolette; Duca, Edward

    2014-01-01

    Marine littering is a global concern and every single year tons of litter end up in the ocean all around the globe. It has become such a problem that the waste has amalgamated into huge ‘islands’ floating in the world’s oceans. http://www.um.edu.mt/think/pollution-around-maltas-sea/

  15. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki;

    2010-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s. Radi...

  16. The Sea Beside Us

    Science.gov (United States)

    Watling, Carol; Hallard Raymond E.

    1974-01-01

    The Sea Beside Us for the Special Child is a project in Delaware with three goals: providing outdoor and overnight experiences for handicapped children; introducing these students to beach, bay, and marsh environments; and increasing the number of special education teachers incorporating seashore studies in their teaching curriculum. (LS)

  17. Sea-Level Projections from the SeaRISE Initiative

    Science.gov (United States)

    Nowicki, Sophie; Bindschadler, Robert

    2011-01-01

    SeaRISE (Sea-level Response to Ice Sheet Evolution) is a community organized modeling effort, whose goal is to inform the fifth IPCC of the potential sea-level contribution from the Greenland and Antarctic ice sheets in the 21st and 22nd century. SeaRISE seeks to determine the most likely ice sheet response to imposed climatic forcing by initializing an ensemble of models with common datasets and applying the same forcing to each model. Sensitivity experiments were designed to quantify the sea-level rise associated with a change in: 1) surface mass balance, 2) basal lubrication, and 3) ocean induced basal melt. The range of responses, resulting from the multi-model approach, is interpreted as a proxy of uncertainty in our sea-level projections. http://websrv.cs .umt.edu/isis/index.php/SeaRISE_Assessment.

  18. AFSC/RACE/EcoFOCI: 2011 Chukchi Sea Cruise MB11-01/1MB11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A total of 64 stations were occupied along onshore-offshore transect lines from the Bering Strait to Barrow Canyon. At each station we sampled zooplankton using a...

  19. The sea is your mirror

    OpenAIRE

    Parenthoen, Marc; Murie, Fred; Thery, Flavien

    2015-01-01

    The Sea Is Your Mirror is an artistic interactive experience where surface cerebral electromagnetic waves from a participant wearing an EEG sensor headset are depicted in real-time as ocean waves in an animated 3D environment. The aim of this article is to describe the sea wave model used for the sea state animation and how it is connected to the brain computer interface (BCI). The sea state is animated by the groupy choppy wave model that provides nonlinear sea states with wave groups and as...

  20. Dead Sea Rate of Evaporation

    OpenAIRE

    Abdelaziz L. AL-Khlaifat

    2008-01-01

    The Dead Sea is exceptional by many standards. It is the saltiest and lowest lake in the world. Moreover it is a closed lake with very large variations in its water level caused by both man-made and natural oscillations of the components that make up the water balance. Most of the fundamental studies on the Dead Sea focused on the sea water contents, Dead Sea geology, salt origin, ground-water sea intrusion, and qualitative analysis of the material balance. The objective of the present paper ...

  1. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    Aerosols are important climactically. Their specific emissions are key to reducing the uncertainty in global climate models. Marine aerosols make up the largest source of primary aerosols to the Earth's atmosphere. Uncertainty in marine aerosol mass and number flux lies in separating primary...... emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use of a...... cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...

  2. Changing Sea Levels

    Science.gov (United States)

    Pugh, David

    2004-04-01

    Flooding of coastal communities is one of the major causes of environmental disasters world-wide. This textbook explains how sea levels are affected by astronomical tides, weather effects, ocean circulation and climate trends. Based on courses taught by the author in the U.K. and the U.S., it is aimed at undergraduate students at all levels, with non-basic mathematics being confined to Appendices and a website http://publishing.cambridge.org/resources/0521532183/.

  3. Wood decay at sea

    Science.gov (United States)

    Charles, François; Coston-Guarini, Jennifer; Guarini, Jean-Marc; Fanfard, Sandrine

    2016-08-01

    The oceans and seas receive coarse woody debris since the Devonian, but the kinetics of wood degradation remains one of many unanswered questions about the fate of driftwood in the marine environment. A simple gravimetric experiment was carried out at a monitoring station located at the exit of a steep, forested Mediterranean watershed in the Eastern Pyrenees. The objective was to describe and quantify, with standardized logs (in shape, structure and constitution), natural degradation of wood in the sea. Results show that the mass decrease of wood logs over time can be described by a sigmoidal curve. The primary process of wood decay observed at the monitoring station was due to the arrival and installation of wood-boring species that consumed more than half of the total wood mass in six months. Surprisingly, in a region where there is little remaining wood marine infrastructure, "shipworms", i.e. xylophagous bivalves, are responsible for an important part of this wood decay. This suggests that these communities are maintained probably by a frequent supply of a large quantity of riparian wood entering the marine environment adjacent to the watershed. By exploring this direct link between terrestrial and marine ecosystems, our long term objective is to determine how these supplies of terrestrial organic carbon can sustain wood-based marine communities as it is observed in the Mediterranean Sea.

  4. Sea-Level climate variability in the Mediterranean Sea

    OpenAIRE

    Bonaduce, Antonio

    2012-01-01

    Sea-level variability is characterized by multiple interacting factors described in the Fourth Assessment Report (Bindoff et al., 2007) of the Intergovernmental Panel on Climate Change (IPCC) that act over wide spectra of temporal and spatial scales. In Church et al. (2010) sea-level variability and changes are defined as manifestations of climate variability and change. The European Environmental Agency (EEA) defines sea level as one of most important indicators for monitoring climate chan...

  5. The impacts of the Preceding Wintertime Arctic Oscillation on November seesaw in Northern Extratropical Sea Level Pressure and the possible mechanisms

    Science.gov (United States)

    Ahn, Joong-Bae; Choi, Yeon-Woo; Kryjov, Vladimir N.

    2016-04-01

    The present study suggests that wintertime Arctic Oscillation (AO) plays a significant role in modulating following November circulation. The application of a set of statistical methods shows that a response of November sea level pressure (SLP) to the preceding wintertime AO operates on a hemispheric scale (Choi et al., 2015). At high and middle latitudes, this response is a well-pronounced seesaw in SLP between the Eastern and Western Hemispheres. Winters of the positive AO polarity tend to be followed by positive SLP anomalies spanning the whole Northern Eurasia and negative SLP anomalies extending from the Bering Sea through the Western North Atlantic. Opposite SLP anomalies prevail after winters of the negative AO polarity. The response of November SLP to the preceding wintertime AO closely resembles the first empirical orthogonal function of November SLP. That is, the polarity of the wintertime AO precedes the polarity of the leading mode of variability of November SLP over the Northern Hemisphere. The wintertime AO exerts a 9-month lag impact on November circulation due to the re-emergence of a sea surface temperature anomaly over the western North Atlantic. Acknowledgements This work was funded by the Korea Meteorological Administration Research and Development Program under grant KMIPA 2015-2081 and Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under Grant Project No. PJ009353, Republic of Korea. Reference Choi, Y.-W., J.-B. Ahn, V. N. Kryjov, 2015. November seesaw in northern extratropical sea level pressure and its linkage to the preceding wintertime Arctic Oscillation, Int. J. Climatol., DOI: 10.1002/joc.4431

  6. Wind-driven mixing causes a reduction in the strength of the continental shelf carbon pump in the Chukchi Sea (Invited)

    Science.gov (United States)

    Hauri, C.

    2013-12-01

    Dynamic and complex physical and biological processes drive the carbonate system chemistry of the Chukchi Sea. The inflow of nutrient-rich Pacific water through the Bering Straight and sustained periods of solar radiation in summer turn this polar shelf into one of the most productive ecosystems in the world. High rates of primary production (~ 470 g C m-2 y-1) and low pelagic grazing rates draw down pCO2 at the surface and support large fluxes of organic carbon to a rich benthic ecosystem. Much of this carbon is remineralized, leading to elevated pCO2 in bottom and subsurface waters, which are thought to be isolated from the atmosphere by strong stratification. Subsequent shelf to basin transport of remineralized carbon and organic matter into the interior Arctic Ocean are believed to support a globally important CO2 sink, as well as maintain high pCO2 levels in bottom waters along their circulation-driven northward journey. Here, I document a new mechanism of carbon cycling in the Chukchi Sea that substantially reduces the net strength of this globally significant carbon sink. Surface pCO2 measurements and wind analysis suggest that annually occurring storm-induced mixing events during autumn months disrupt water column stratification and mix remineralized carbon from subsurface waters to the surface, leading to strong outgassing of CO2 to the atmosphere. This newly observed physical driver weakens the estimated strength of the continental shelf carbon pump in the Chukchi Sea from an uptake of 38 Tg C y-1 to 18-27 Tg C y-1 and revises our knowledge of the dynamics of carbon cycling on this polar shelf. An improved understanding of the distribution and transport of carbon on the shelf is crucial to elucidate how the Chukchi Sea will respond to ongoing ocean acidification and climate change.

  7. Sea level monitoring in Mozambique

    OpenAIRE

    Nhampulo, C.I.S.; Ruby, J,

    2002-01-01

    Observing changes in the rise of relative sea level has resulted from the balance between the sea level rise due to the global warming of the planet, and the vertical displacements of the coast due to geological movements. The main objective of this paper is to outsource information about sea level monitoring in Mozambique, as part of a common global effort aiming to colect and analyse data that can help in understanding physical processes envolving ocean basins or oceans as a hole. Tidal ...

  8. Air sea ratio reduction initiative

    Energy Technology Data Exchange (ETDEWEB)

    Oberle, Jean

    2010-09-15

    Airfreight is the most expensive mode of transportation as well as the most impacting in terms of CO{sup 2} emissions. It is 7 times more expensive on average to ship by air than shipping by sea 1. Airfreight transportation mode emits 30 times more CO{sup 2} than sea freight mode 2. These elements provided a compelling platform to design a global logistics program to initiate a modal shift from air to sea freight without compromising service to customers.

  9. Sea Otter, River Otter. The Wonder Series.

    Science.gov (United States)

    Robinson, Sandra Chisholm

    This curriculum guide is all about otters and provides information on both sea and river otters. Included are activities related to the diet of sea otters, the adaptations sea otters have made to live in the sea, their tool-using abilities, where they live and how to spot them, comparative anatomy of sea and river otters, and otter movement. The…

  10. Japan nuclear ship sea trial

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Hiroshi; Kitamura, Toshikatus; Mizushima, Toshihiko [Japan Atomic Energy Research Inst., Mutsu, Aomori (Japan). Mutsu Establishment] [and others

    1992-01-01

    The sea trial of the first Japan nuclear Ship `MUTSU` was conducted from the end of October to December in 1990. The purpose of the sea trial was to verify the nuclear propulsive performances and maneuverabilities. The present report describes the results of the sea trial. These results are classified into four items: 1. Speed test and engineering performance tests 2. Maneuvering performance tests 3. Vibration tests 4. Other tests. Acceptable performances were demonstrated, as expected in the original design. The experience of the use of the Global Positioning System (GPS), which were newly adopted for the sea trial, is also reported. (author).

  11. Japan nuclear ship sea trial

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Hiroshi; Kitamura, Toshikatus; Mizushima, Toshihiko (Japan Atomic Energy Research Inst., Mutsu, Aomori (Japan). Mutsu Establishment) (and others)

    1992-01-01

    The sea trial of the first Japan nuclear Ship 'MUTSU' was conducted from the end of October to December in 1990. The purpose of the sea trial was to verify the nuclear propulsive performances and maneuverabilities. The present report describes the results of the sea trial. These results are classified into four items: 1. Speed test and engineering performance tests 2. Maneuvering performance tests 3. Vibration tests 4. Other tests. Acceptable performances were demonstrated, as expected in the original design. The experience of the use of the Global Positioning System (GPS), which were newly adopted for the sea trial, is also reported. (author).

  12. Japan nuclear ship sea trial

    International Nuclear Information System (INIS)

    The sea trial of the first Japan nuclear Ship 'MUTSU' was conducted from the end of October to December in 1990. The purpose of the sea trial was to verify the nuclear propulsive performances and maneuverabilities. The present report describes the results of the sea trial. These results are classified into four items: 1. Speed test and engineering performance tests 2. Maneuvering performance tests 3. Vibration tests 4. Other tests. Acceptable performances were demonstrated, as expected in the original design. The experience of the use of the Global Positioning System (GPS), which were newly adopted for the sea trial, is also reported. (author)

  13. AIR / SEA RESCUE LAUNCHES

    Directory of Open Access Journals (Sweden)

    W.H. Rice

    2012-02-01

    Full Text Available The Motor Boat Wing of the South African Air Force was inaugurated some thirty eight years ago.With its main base at Gordon's Bay, the wing was formed to operate the various marine craft used to provide a service to the flying component of the South African Air Force. Its main function was to be air/sea rescue, but it also had to man and maintain armoured target boats, seaplane tenders, marine tenders and the 'bomb scows', used for recovering practise bombs and missiles and for laying and lifting moorings.

  14. Deep-sea fungi

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Damare, S.

    • Institut fur Biotechno\\ogle. Biotechnikum. Walter Rathenau Strasse 49A, 17489GrcJf~wald.Germany. 265 266 Raghukumar and Damare from water samples collected from the subtropical Atlantic Ocean, from the surface to a depth of 4,500 m using sterile van Dom... Calcareous shells %5, Bay ofBengal 73 Only preserved specimens CFU CFt.: Chapter IS • Deep-Sea Fungi 267 fungi were isolated from surface-sterilized calcareous fragments collected from a depth of 300 to 860 m in the Bay of Bengal (73). These fungi were...

  15. Sea shore in Cyprus

    OpenAIRE

    2016-01-01

    Black and white photograph, showing a winter’s day at a deserted sea shore in Cyprus - Μαυρόασπρη κάρτ ποστάλ που απεικονίζει μια χειμωνιάτικη μέρα σε μια ερημική ακτή στην Κύπρο.

  16. The Sea Around Us

    Science.gov (United States)

    Carson, Rachel L.

    1991-12-01

    Published in 1951, The Sea Around Us is one of the most remarkably successful books ever written about the natural world. Rachel Carson's rare ability to combine scientific insight with moving, poetic prose catapulted her book to first place on The New York Times best-seller list, where it enjoyed wide attention for thirty-one consecutive weeks. It remained on the list for more than a year and a half and ultimately sold well over a million copies, has been translated into 28 languages, inspired an Academy Award-winning documentary, and won both the 1952 National Book Award and the John Burroughs Medal. This classic work remains as fresh today as when it first appeared. Carson's writing teems with stunning, memorable images--the newly formed Earth cooling beneath an endlessly overcast sky; the centuries of nonstop rain that created the oceans; giant squids battling sperm whales hundreds of fathoms below the surface; and incredibly powerful tides moving 100 billion tons of water daily in the Bay of Fundy. Quite simply, she captures the mystery and allure of the ocean with a compelling blend of imagination and expertise. Reintroducing a classic work to a whole new generation of readers, this Special Edition features a new chapter written by Jeffrey Levinton, a leading expert in marine ecology, that brings the scientific side of The Sea Around Us completely up to date. Levinton incorporates the most recent thinking on continental drift, coral reefs, the spread of the ocean floor, the deterioration of the oceans, mass extinction of sea life, and many other topics. In addition, acclaimed nature writer Ann Zwinger has contributed a brief foreword. Today, with the oceans endangered by the dumping of medical waste and ecological disasters such as the Exxon oil spill in Alaska, this illuminating volume provides a timely reminder of both the fragility and the importance of the ocean and the life that abounds within it. Anyone who loves the sea, or who is concerned about our

  17. Two Sea-Level Challenges

    Science.gov (United States)

    Galvin, C.

    2008-12-01

    "No place on the sandy ocean shores of the world has been shown to be eroding because of sea level rise." This statement appeared nearly 19 years ago in bold print at the top of the page in a brief article published in Shore and Beach (Galvin,1990). The term "sea level rise" was defined in 1990 as follows: "In this statement, "sea level rise" has the meaning that the average person on the street usually attaches to that term. That is, sea level is rising; not, as in some places like the Mississippi River delta, land level is sinking." While still a subject of controversy, it is now (2008) increasingly plausible (Tornqvist et al,2008) that damage from Hurricane Katrina was significantly worse on the Mississippi River delta because floodwaters exploited wetlands and levees whose elevations had been lowered by decades of compaction in the underlying soil. (1) "Sea level" commonly appears in the literature as "relative sea level rise", occurring that way in 711 publications between 1980 and 2009 (GeoRef database on 8 Sep 08). "Relative sea level rise" does not appear in the 2005 AGI Glossary. The nearest Glossary term is "relative change in sea level", but that term occurs in only 12 publications between 1980 and 2009. The Glossary defines this term in a sequence stratigraphy sense, which infers that "relative sea level rise" is the sum of bottom subsidence and eustatic sea level rise. In plain English, "relative sea level rise" means "water depth increase". For present day coastal environments, "relative sea level rise" is commonly used where eustatic sea level rise is less than subsidence, that is, where the magnitude of actual sea level rise is smaller than the magnitude of subsidence. In that situation, "relative sea level rise" misleads both the average person and the scientist who is not a coastal geologist. Thus, the first challenge is to abandon "relative sea level rise" in favor of "water depth increase", in order that the words accurately descibe what happens

  18. Seasonal and interannual variation in the planktonic communities of the northeastern Chukchi Sea during the summer and early fall

    Science.gov (United States)

    Questel, Jennifer M.; Clarke, Cheryl; Hopcroft, Russell R.

    2013-09-01

    We analyzed the seasonal and interannual variability of the planktonic communities in a densely sampled region of the northeastern Chukchi Sea as part of a multidisciplinary ecosystem study from 2008 to 2010. Observations of chlorophyll-a, inorganic macronutrients, and zooplankton (using both 150-μm and 505-μm mesh nets) were made within two 900-NM 2 grids (Klondike and Burger) at high spatial resolution three times each in 2008 and 2009, with a third grid (Statoil) sampled twice in 2010. Sea-ice conditions prior to sampling varied notably during the study: seasonal sea ice retreat was earlier and sea-surface temperatures (SSTs) were warmer in 2009 than in 2008, whereas SSTs for 2010 were intermediate between the 2008 and 2009 values. Eighty taxonomic categories of zooplankton, including 11 meroplanktonic categories, were recorded, with the greatest diversity found within the copepods (25 species), followed by the cnidarians (11 species). All species are typical for the region and most are seeded from the Bering Sea. A seasonal progression of the community structure was apparent over each survey area and was likely influenced by temperature. Cold oceanographic conditions in 2008 likely slowed growth and development of the zooplankton, such that holozooplankton abundance averaged 2389 and 106 individuals m-3 and biomass averaged 10.5 and 8.3 mg DW m-3 in the 150- and 505-μm nets, respectively. An early phytoplankton bloom in 2009 apparently supported a zooplankton community of greater abundance, but moderate biomass, averaging 6842 and 189 individuals m-3, and 16.3 and 7.0 mg DW m-3 in the 150- and 505-μm nets, respectively. Highest zooplankton abundance and biomass values among the three years occurred in 2010: 7396 and 198 individuals m-3 and 102.9 and 33.5 mg DW m-3 in the 150- and 505-μm nets, respectively. Holozooplankton biomass changes were driven by increases in large-bodied, lipid-rich copepods. The contribution of meroplankton was substantial in this

  19. Deep sea biophysics

    International Nuclear Information System (INIS)

    A collection of deep-sea bacterial cultures was completed. Procedures were instituted to shelter the culture collection from accidential warming. A substantial data base on the rates of reproduction of more than 100 strains of bacteria from that collection was obtained from experiments and the analysis of that data was begun. The data on the rates of reproduction were obtained under conditions of temperature and pressure found in the deep sea. The experiments were facilitated by inexpensively fabricated pressure vessels, by the streamlining of the methods for the study of kinetics at high pressures, and by computer-assisted methods. A polybarothermostat was used to study the growth of bacteria along temperature gradients at eight distinct pressures. This device should allow for the study of microbial processes in the temperature field simulating the environment around buried HLW. It is small enough to allow placement in a radiation field in future studies. A flow fluorocytometer was fabricated. This device will be used to determine the DNA content per cell in bacteria grown in laboratory culture and in microorganisms in samples from the ocean. The technique will be tested for its rapidity in determining the concentration of cells (standing stock of microorganisms) in samples from the ocean

  20. Sea ice terminology

    Energy Technology Data Exchange (ETDEWEB)

    1980-09-01

    A group of definitions of terms related to sea ice is presented, as well as a graphic representation of late winter ice zonation of the Beaufort Sea Coast. Terms included in the definition list are belt, bergy bit, bight, brash ice, calving, close pack ice, compacting, compact pack ice, concentration, consolidated pack ice, crack, diffuse ice edge, fast ice, fast-ice boundary, fast-ice edge, first-year ice, flaw, flaw lead, floe, flooded ice, fractured, fractured zone, fracturing, glacier, grey ice, grey-white ice, growler, hummock, iceberg, iceberg tongue, ice blink, ice boundary, ice cake, ice edge, ice foot, ice free, ice island, ice shelf, large fracture, lead, medium fracture, multiyear ice, nilas, old ice, open pack ice, open water, pack ice, polar ice, polynya, puddle, rafted ice, rafting, ram, ridge, rotten ice, second-year ice, shearing, shore lead, shore polynya, small fracture, strip, tabular berg, thaw holes, very close pack ice, very open pack ice, water sky, young coastal ice, and young ice.