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Sample records for bering sea

  1. Dynamic Topography of the Bering Sea

    Science.gov (United States)

    2011-01-01

    Bering Sea. Comparisons also indicate that MDT estimates derived from the latest Gravity Recovery and Climate Experiment geoid model have more in common...with the presented sea surface topography than with the MDTs based on earlier versions of the geoid . The presented MDT will increase the accuracy of...estimating the geoid in the Bering Sea. 15. SUBJECT TERMS dynamic topography, sea surface height, Bering Sea, 4DVar 16. SECURITY CLASSIFICATION OF: a

  2. 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.

  3. 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.

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

    Institute of Scientific and Technical Information of China (English)

    ZHOU BoTao; WANG HuiJun

    2008-01-01

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

  5. 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

  6. 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...

  7. Pollen evidence for late pleistocene bering land bridge environments from Norton Sound, Northeastern Bering Sea, Alaska

    Science.gov (United States)

    Ager, T.A.; Phillips, R.L.

    2008-01-01

    After more than half a century of paleoenvironmental investigations, disagreements persist as to the nature of vegetation type and climate of the Bering land bridge (BLB) during the late Wisconsin (Sartan) glacial interval. Few data exist from sites on the former land bridge, now submerged under the Bering and Chukchi Seas. Two hypotheses have emerged during the past decade. The first, based on pollen data from Bering Sea islands and adjacent mainlands of western Alaska and Northeast Siberia, represents the likely predominant vegetation on the Bering land bridge during full-glacial conditions: graminoid-herb-willow tundra vegetation associated with cold, dry winters and cool, dry summer climate. The second hypothesis suggests that dwarf birch-shrub-herb tundra formed a broad belt across the BLB, and that mesic vegetation was associated with cold, snowier winters and moist, cool summers. As a step towards resolving this controversy, a sediment core from Norton Sound, northeastern Bering Sea was radiocarbon dated and analyzed for pollen content. Two pollen zones were identified. The older, bracketed by radiocarbon ages of 29,500 and 11,515 14C yr BP, contains pollen assemblages composed of grass, sedge, wormwood, willow, and a variety of herb (forb) taxa. These assemblages are interpreted to represent graminoid-herb-willow tundra vegetation that developed under an arid, cool climate regime. The younger pollen zone sediments were deposited about 11,515 14C yr BP, when rising sea level had begun to flood the BLB. This younger pollen zone contains pollen of birch, willow, heaths, aquatic plants, and spores of sphagnum moss. This is interpreted to represent a Lateglacial dwarf birch-heath-willow-herb tundra vegetation, likely associated with a wetter climate with deeper winter snows, and moist, cool summers. This record supports the first hypothesis, that graminoid-herb-willow tundra vegetation extended into the lowlands of the BLB during full glacial conditions of the

  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. 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...

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

    Science.gov (United States)

    Miksis-Olds, Jennifer L; Madden, Laura E

    2014-01-01

    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.

  13. 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.

  14. Latitudinal distribution of iodine in sediments in the Chukchi Sea and the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    GAO; Aiguo; (高爱国); LIU; Yanguang; (刘焱光); ZHANG; Daojian; (张道建); SUN; Haiqing; (孙海清)

    2003-01-01

    Iodine is an important trace element associated closely with human being, and it will influence human's normal growth if lacking it. Meanwhile, iodine is an important catalyzer, and is important in atmospheric chemistry study. In nature, iodine is rich mainly in marine organism and sediment, and marine sediment has the largest storage of iodine. The analysis results of sediment samples obtained by the First Chinese National Arctic Research Expedition indicate that iodine contents in sediments in the Chukchi Sea and the Bering Sea are 98.1(10-6 and 73.8(10-6, respectively, which are higher than those in sediments of Chinese marginal seas and the southern Pacific Ocean, and show the trend of increase from low latitude to high latitude. This paper proposes a pattern of iodine latitudinal distribution on the basis of the distribution characteristic of iodine and its enrichment mechanism in sediments of the Chukchi Sea and the Bering Sea.

  15. Late summer zoogeography of the northern Bering and Chukchi seas

    Science.gov (United States)

    Sigler, Michael F.; Mueter, Franz J.; Bluhm, Bodil A.; Busby, Morgan S.; Cokelet, Edward D.; Danielson, Seth L.; Robertis, Alex De; Eisner, Lisa B.; Farley, Edward V.; Iken, Katrin; Kuletz, Kathy J.; Lauth, Robert R.; Logerwell, Elizabeth A.; Pinchuk, Alexei I.

    2017-01-01

    Ocean currents, water masses, and seasonal sea ice formation contribute to determining relationships among the biota of the Bering and Chukchi seas. The Bering Sea communicates with the Chukchi Sea via northward advection of water, nutrients, organic matter, and plankton through Bering Strait. We used data from concurrent surveys of zooplankton, pelagic fishes and jellyfish, epibenthic fishes and invertebrates, and seabirds to identify faunal distribution patterns and environmental factors that are related to these faunal distributions within the US portions of the Chukchi Sea shelf and Bering Sea shelf north of Nunivak Island. Regional differences in late summer (August-September) distributions of biota largely reflected the underlying hydrography. Depth, temperature, salinity, stratification, and chlorophyll a, but less so sediment-related or nutrient-related factors, were related to the distributions of the assemblages (zooplankton: depth, salinity, stratification; pelagic fishes and jellyfish: depth, stratification, chlorophyll a; epibenthic fishes and invertebrates: depth, temperature, salinity; seabirds: temperature, salinity, stratification). These six environmental factors that most influenced distributions of zooplankton, pelagic fishes/jellyfish, epibenthic fishes and invertebrate, and seabird assemblages likely can be simplified to three factors reflecting bottom depth, water mass, and their stratification and productivity (which are tightly linked in the study region). The assemblages were principally structured from nearshore to offshore and from south to north. The nearshore to offshore contrast usually was stronger in the south, where the enormous discharge of the Yukon River is more apparent and extends farther offshore, influencing zooplankton, pelagic fish/jellyfish, and seabird assemblages. Some assemblages overlapped spatially (e.g., seabird and zooplankton), indicating shared influential environmental factors or trophic linkages among

  16. 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,...

  17. AFSC/RACE/EcoFOCI: 2010 Eastern Bering Sea Juvenile Survey - 1MF10

    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,...

  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/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...

  1. 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...

  2. 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...

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

    Data.gov (United States)

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

  4. AFSC/ABL: 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...

  5. 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...

  6. 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...

  7. 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....

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

    Data.gov (United States)

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

  9. AFSC/RACE/MACE: Results of 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...

  10. 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....

  11. 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...

  12. 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....

  13. 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....

  14. 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)...

  15. 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...

  16. 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...

  17. 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...

  18. 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 included...

  19. Seasonal distribution of short-tailed shearwaters and their prey in the Bering and Chukchi seas

    Science.gov (United States)

    Nishizawa, Bungo; Matsuno, Kohei; Labunski, Elizabeth A.; Kuletz, Kathy J.; Yamaguchi, Atsushi; Watanuki, Yutaka

    2017-01-01

    The short-tailed shearwater (Ardenna tenuirostris) is one of the abundant marine top predators in the Pacific; this seabird spends its non-breeding period in the northern North Pacific during May-October and many visit the southern Chukchi Sea in August-September. We examined potential factors affecting this seasonal pattern of distribution by counting short-tailed shearwaters from boats. Their main prey, krill, was sampled by net tows in the southeastern Bering Sea/Aleutian Islands and in the Bering Strait/southern Chukchi Sea. Short-tailed shearwaters were mainly distributed in the southeastern Bering Sea/Aleutian Islands (60 ± 473 birds km-2) in July 2013, and in the Bering Strait/southern Chukchi Sea (19 ± 91 birds km-2) in September 2012. In the Bering Strait/southern Chukchi Sea, krill size was greater in September 2012 (9.6 ± 5.0 mm in total length) than in July 2013 (1.9 ± 1.2 mm). Within the Bering Strait/southern Chukchi Sea in September 2012, short-tailed shearwaters occurred more frequently in cells (50 × 50 km) where large-sized krill were more abundant. These findings, and information previously collected in other studies, suggest that the seasonal northward movement of short-tailed shearwaters might be associated with the seasonal increase in krill size in the Bering Strait/southern Chukchi Sea. We could not, however, rule out the possibility that large interannual variation in krill abundance might influence the seasonal distribution of shearwaters. This study highlights the importance of krill, which is advected from the Pacific, as an important prey of top predators in the Arctic marine ecosystem.

  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. 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....

  3. 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...

  4. 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...

  5. 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...

  6. 76 FR 17360 - Fisheries of the Exclusive Economic Zone Off Alaska; Octopus in the Bering Sea and Aleutian...

    Science.gov (United States)

    2011-03-29

    ... Economic Zone Off Alaska; Octopus in the Bering Sea and Aleutian Islands Management Area AGENCY: National...-specified reserve to the initial total allowable catch of octopus in the Bering Sea and Aleutian Islands... CFR part 679. The 2011 initial total allowable catch (ITAC) of octopus in the BSAI was ]...

  7. 76 FR 55276 - Fisheries of the Exclusive Economic Zone Off Alaska; Octopus in the Bering Sea and Aleutian Islands

    Science.gov (United States)

    2011-09-07

    ... Economic Zone Off Alaska; Octopus in the Bering Sea and Aleutian Islands AGENCY: National Marine Fisheries...; closure. SUMMARY: NMFS is prohibiting retention of octopus in the Bering Sea and Aleutian Islands (BSAI). This action is necessary because the 2011 total allowable catch of octopus in the BSAI has been...

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

    Science.gov (United States)

    2013-09-17

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

  9. 76 FR 59924 - Fisheries of the Exclusive Economic Zone Off Alaska; Sharks in the Bering Sea and Aleutian...

    Science.gov (United States)

    2011-09-28

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

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

    Science.gov (United States)

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

    2013-09-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

  13. Chemistry of Aerosols over Chukchi Sea and Bering Sea

    Institute of Scientific and Technical Information of China (English)

    朱赖民; 陈立奇; 杨绪林; 杜俊民; 张远辉

    2004-01-01

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

  14. The Bering Sea: Communication with the Western Subarctic Gyre, Mesoscale Activity, Shelf-Basin Exchange, and the Flow Through Bering Strait

    Science.gov (United States)

    2011-03-01

    support water column primary production and the settling of organic matter to the benthos . C. DOWNSTREAM EFFECTS Satellite records of the Arctic sea...Science 311:1461–1464. Grebmeier J.M., Cooper L.W. (1995) Influence of the St. Lawrence Island Polynya upon the Bering Sea benthos . Journal of

  15. Arctic sea ice decline: Projected changes in timing and extent of sea ice in the Bering and Chukchi Seas

    Science.gov (United States)

    Douglas, D.C.

    2010-01-01

    The Arctic region is warming faster than most regions of the world due in part to increasing greenhouse gases and positive feedbacks associated with the loss of snow and ice cover. One consequence has been a rapid decline in Arctic sea ice over the past 3 decades?a decline that is projected to continue by state-of-the-art models. Many stakeholders are therefore interested in how global warming may change the timing and extent of sea ice Arctic-wide, and for specific regions. To inform the public and decision makers of anticipated environmental changes, scientists are striving to better understand how sea ice influences ecosystem structure, local weather, and global climate. Here, projected changes in the Bering and Chukchi Seas are examined because sea ice influences the presence of, or accessibility to, a variety of local resources of commercial and cultural value. In this study, 21st century sea ice conditions in the Bering and Chukchi Seas are based on projections by 18 general circulation models (GCMs) prepared for the fourth reporting period by the Intergovernmental Panel on Climate Change (IPCC) in 2007. Sea ice projections are analyzed for each of two IPCC greenhouse gas forcing scenarios: the A1B `business as usual? scenario and the A2 scenario that is somewhat more aggressive in its CO2 emissions during the second half of the century. A large spread of uncertainty among projections by all 18 models was constrained by creating model subsets that excluded GCMs that poorly simulated the 1979-2008 satellite record of ice extent and seasonality. At the end of the 21st century (2090-2099), median sea ice projections among all combinations of model ensemble and forcing scenario were qualitatively similar. June is projected to experience the least amount of sea ice loss among all months. For the Chukchi Sea, projections show extensive ice melt during July and ice-free conditions during August, September, and October by the end of the century, with high agreement

  16. An inverse modeling study of circulation in the Eastern Bering Sea during 2007-2010

    Science.gov (United States)

    Panteleev, Gleb; Yaremchuk, Max; Francis, Oceana; Stabeno, Phyllis J.; Weingartner, T.; Zhang, J.

    2016-06-01

    A two-way nested 4d-variational data assimilation system is implemented in the Eastern Bering Sea (EBS) to investigate changes in circulation and thermodynamic state for a 3.8 year period. Assimilated observations include data from 19 moorings deployed on the shelf and in the Bering Strait, 1705 hydrographic stations occupied during eight surveys, and remotely sensed sea surface temperature and sea surface height (SSH) data. Validation of the presented 4dVar reanalysis against the output of two sequential data-assimilative systems (the Bering Ecosystem Study ice-ocean Modeling and Assimilation System (BESTMAS) and the Arctic Cap Nowcast-Forecast System (ACNFS)) has shown that the product is more consistent with the observed transports in the Bering Strait and in the EBS interior both in terms of their magnitude and time variability. Analysis of the data-optimized solution quantifies a sequence of wind-forced events that resulted in the anomalous heat and freshwater transports through the Bering Strait, including a 28 day long flow reversal that occurred in November 2009 and carried Siberian Coastal Current water down to the Gulf of Anadyr. Lagrangian study of the Arctic-bound Pacific waters indicates the extreme importance of the cross-shelf exchange along the path of the Bering Slope Current and quantifies the spectrum of residence times for the waters entering EBS through Unimak Pass and through Aleutian passages. Residence times in the EBS cold pool are diagnosed to be 2-3 times longer than those in the surrounding waters.

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

    Institute of Scientific and Technical Information of China (English)

    MENG Xiangmei; LI Guanbao; HAN Guozhong; KAN Guangming

    2015-01-01

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

  18. 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 is...

  19. 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...

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

    Data.gov (United States)

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

  1. 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...

  2. 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 spatio-temporal...

  3. 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...

  4. 75 FR 56485 - Groundfish Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab...

    Science.gov (United States)

    2010-09-16

    ... for Bering Sea/Aleutian Islands King and Tanner Crabs (FMP). The FMP was prepared by the North Pacific... recordkeeping requirements. Dated: September 13, 2010. Eric C. Schwaab, Assistant Administrator for...

  5. 75 FR 48298 - Groundfish Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea/Aleutian Islands Crab...

    Science.gov (United States)

    2010-08-10

    ... fisheries under the Fishery Management Plan for Bering Sea/Aleutian Islands King and Tanner Crabs (FMP). The...: August 4, 2010. Eric C. Schwaab, Assistant Administrator for Fisheries, National Marine Fisheries...

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

    Directory of Open Access Journals (Sweden)

    Chadwick V Jay

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

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

    Directory of Open Access Journals (Sweden)

    Carlos Alvarez Zarikian

    2011-03-01

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

  8. The application of ERTS imagery to monitoring Arctic sea ice. [mapping ice in Bering Sea, Beaufort Sea, Canadian Archipelago, and Greenland Sea

    Science.gov (United States)

    Barnes, J. C. (Principal Investigator); Bowley, C. J.

    1974-01-01

    The author has identified the following significant results. Because of the effect of sea ice on the heat balance of the Arctic and because of the expanding economic interest in arctic oil and minerals, extensive monitoring and further study of sea ice is required. The application of ERTS data for mapping ice is evaluated for several arctic areas, including the Bering Sea, the eastern Beaufort Sea, parts of the Canadian Archipelago, and the Greenland Sea. Interpretive techniques are discussed, and the scales and types of ice features that can be detected are described. For the Bering Sea, a sample of ERTS-1 imagery is compared with visual ice reports and aerial photography from the NASA CV-990 aircraft. The results of the investigation demonstrate that ERTS-1 imagery has substantial practical application for monitoring arctic sea ice. Ice features as small as 80-100 m in width can be detected, and the combined use of the visible and near-IR imagery is a powerful tool for identifying ice types. Sequential ERTS-1 observations at high latitudes enable ice deformations and movements to be mapped. Ice conditions in the Bering Sea during early March depicted in ERTS-1 images are in close agreement with aerial ice observations and photographs.

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

    Science.gov (United States)

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

    2015-12-01

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

  10. 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.

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

    Science.gov (United States)

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

    2016-06-01

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

  12. 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.

  13. 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...

  14. 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.

  15. 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

  16. 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.

  17. Growth and condition of juvenile chum and pink salmon in the northeastern Bering Sea

    Science.gov (United States)

    Wechter, Melissa E.; Beckman, Brian R.; Andrews, Alexander G., III; Beaudreau, Anne H.; McPhee, Megan V.

    2017-01-01

    As the Arctic continues to warm, abundances of juvenile Pacific salmon (Oncorhynchus spp.) in the northern Bering Sea are expected to increase. However, information regarding the growth and condition of juvenile salmon in these waters is limited. The first objective of this study was to describe relationships between size, growth, and condition of juvenile chum (O. keta) and pink (O. gorbuscha) salmon and environmental conditions using data collected in the northeastern Bering Sea (NEBS) from 2003-2007 and 2009-2012. Salmon collected at stations with greater bottom depths and cooler sea-surface temperature (SST) were longer, reflecting their movement further offshore out of the warmer Alaska Coastal Water mass, as the season progressed. Energy density, after accounting for fish length, followed similar relationships with SST and bottom depth while greater condition (weight-length residuals) was associated with warm SST and shallower stations. We used insulin-like growth factor-1 (IGF-1) concentrations as an indicator of relative growth rate for fishes sampled in 2009-2012 and that found fish exhibited higher IGF-1 concentrations in 2010-2012 than in 2009, although these differences were not clearly attributable to environmental conditions. Our second objective was to compare size and condition of juvenile chum and pink salmon in the NEBS between warm and cool spring thermal regimes of the southeastern Bering Sea (SEBS). This comparison was based on a hypothesis informed by the strong role of sea-ice retreat in the spring for production dynamics in the SEBS and prevailing northward currents, suggesting that feeding conditions in the NEBS may be influenced by production in the SEBS. We found greater length (both species) and condition (pink salmon) in years with warm thermal regimes; however, both of these responses changed more rapidly with day of year in years with cool springs. Finally, we compared indicators of energy allocation between even and odd brood

  18. A macrodescriptor perspective of ecological attributes for the Bering and Barents Seas

    Science.gov (United States)

    Megrey, Bernard A.; Aydin, Kerim Y.

    2009-10-01

    The eastern Bering Sea (EBS) and Barents Sea (BS) are both high-latitude, subarctic ecosystems that share many similar biophysical and trophic characteristics, and support valuable commercial fisheries. In this paper we compare system-level characteristics that make the Bering and Barents Sea ecosystems unique. We use Ecopath models and systems ecology macrodescriptor metrics applied to the two marine ecosystems to identify key areas of differences and similarities. Metrics calculated include number of species, number of interactions or trophic links, connectivity of the system, number of interactions per species, a measure of directed connectance, and an assessment of overall web interaction strength. In addition, number of basal species, number of top predators, total number of intermediate species, number of cannibals, number of cycles, number of omnivores, number of predators for a prey item, number of prey items for a predator, predator to prey ratio, and other indices were enumerated. Calculated food-web metrics for the eastern Bering and Barents Seas are compared between systems as well as with other similar metrics from published sources. We attempt to relate these observations to the questions of the uniqueness of marine food webs, implications for system stability, how climate impacts the physical environment, how the physical environment affects the structure of fish communities in each sea, and how changes in the physical environment affect the production of fish and the ability of the Bering and Barents Seas to support stable fisheries and productive ecosystems. Results show that the average number of trophic steps from primary producers to predators is shorter in the EBS. In the EBS, trophic pathways are shorter and more linear, there are more benthic species (flatfish and crabs) and there are both pelagic and benthic food webs. The BS is mainly a pelagic ecosystem. More production flows to the detritus pool in the BS most likely due to its deeper

  19. Timing of ice retreat alters seabird abundances and distributions in the southeast Bering Sea.

    Science.gov (United States)

    Renner, Martin; Salo, Sigrid; Eisner, Lisa B; Ressler, Patrick H; Ladd, Carol; Kuletz, Kathy J; Santora, Jarrod A; Piatt, John F; Drew, Gary S; Hunt, George L

    2016-09-01

    Timing of spring sea-ice retreat shapes the southeast Bering Sea food web. We compared summer seabird densities and average bathymetry depth distributions between years with early (typically warm) and late (typically cold) ice retreat. Averaged over all seabird species, densities in early-ice-retreat-years were 10.1% (95% CI: 1.1-47.9%) of that in late-ice-retreat-years. In early-ice-retreat-years, surface-foraging species had increased numbers over the middle shelf (50-150 m) and reduced numbers over the shelf slope (200-500 m). Pursuit-diving seabirds showed a less clear trend. Euphausiids and the copepod Calanus marshallae/glacialis were 2.4 and 18.1 times less abundant in early-ice-retreat-years, respectively, whereas age-0 walleye pollock Gadus chalcogrammus near-surface densities were 51× higher in early-ice-retreat-years. Our results suggest a mechanistic understanding of how present and future changes in sea-ice-retreat timing may affect top predators like seabirds in the southeastern Bering Sea.

  20. 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.

  1. 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.

  2. Shallow-water habitat use by Bering Sea flatfishes along the central Alaska Peninsula

    Science.gov (United States)

    Hurst, Thomas P.

    2016-05-01

    Flatfishes support a number of important fisheries in Alaskan waters and represent major pathways of energy flow through the ecosystem. Despite their economic and ecological importance, little is known about the use of habitat by juvenile flatfishes in the eastern Bering Sea. This study describes the habitat characteristics of juvenile flatfishes in coastal waters along the Alaska Peninsula and within the Port Moller-Herendeen Bay system, the largest marine embayment in the southern Bering Sea. The two most abundant species, northern rock sole and yellowfin sole, differed slightly in habitat use with the latter occupying slightly muddier substrates. Both were more common along the open coastline than they were within the bay, whereas juvenile Alaska plaice were more abundant within the bay than along the coast and used shallow waters with muddy, high organic content sediments. Juvenile Pacific halibut showed the greatest shift in distribution between age classes: age-0 fish were found in deeper waters (~ 30 m) along the coast, whereas older juveniles were found in the warmer, shallow waters within the bay, possibly due to increased thermal opportunities for growth in this temperature-sensitive species. Three other species, starry flounder, flathead sole, and arrowtooth flounder, were also present, but at much lower densities. In addition, the habitat use patterns of spring-spawning flatfishes (northern rock sole, Pacific halibut, and Alaska plaice) in this region appear to be strongly influenced by oceanographic processes that influence delivery of larvae to coastal habitats. Overall, use of the coastal embayment habitats appears to be less important to juvenile flatfishes in the Bering Sea than in the Gulf of Alaska.

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

    Science.gov (United States)

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

    2016-09-01

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

  4. 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.

  5. 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.

  6. Environmental Magnetic Signature Of Late Quaternary Climate and Paleoceanography in the Bering Sea

    Science.gov (United States)

    Platzman, E. S.; Lund, S.; Kirby, M. E.

    2014-12-01

    High latitude drilling during IODP expedition 323 in the Bering Sea provides a unique opportunity to study in detail the evolution of Quaternary paleoceanography, climate and glacial history of the Bering Sea gateway to the Arctic Ocean. Our study focuses on a 400 ky interval of Quaternary marine sediments cored along the Bering Slope. Samples for magnetic analysis were obtained from sites U1339, U1343, U1344, U1345, at depths of 1008-3484 m. Sediments in these cores are a mixture of siliclastic material, derived primarily from terrigeneous sources, and biogenic material. Detailed measurements of the variation in bulk magnetic properties including natural remanent magnetization (NRM), susceptibility, ARM, and IRM, have been used to monitor changes in concentration, composition and grainsize of the magnetic components. In addition, sediment grain size analysis was preformed on biogenic free aliquots at selected intervals. Our results indicate that the dramatic bimodal magnetic intensity signal that alternates between a strong and weak NRM and magnetic susceptibility is associated with relatively course and fine grain sizes repectively. This is the opposite to the pattern estimated by our initial IODP Ex. 323 reports. Current models propose that, as has been observed in the North Atlantic, high intensities are likely to be related to high contributions of terrigenous and glaciomarine sediments deposited during glacial periods and low intensities are likely to occur during interglacials when continental sediments become trapped on the on the shelf. Contrary to this hypothesis, however, we find compelling evidence for a substantial increase in terrigenous input during the interglacial periods and what appears to be a predominantly pelagic signal during the glacial periods. Comparison of our data with other proxy data including oxygen isotopes, NGR, GRA allows us to investigate the possible causal links between these changes and the environmental history of the North

  7. 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.

  8. 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.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    We studied microbially mediated diagenetic processes driven by carbon mineralization in subseafloor sediment of the northeastern Bering Sea Slope to a depth of 745 meters below seafloor (mbsf). Sites U1343, U1344 and U1345 were drilled during Integrated Ocean Drilling Program (IODP) Expedition 32...

  10. 78 FR 76246 - Fisheries of the Exclusive Economic Zone Off Alaska; Several Groundfish Species in the Bering Sea...

    Science.gov (United States)

    2013-12-17

    ... Economic Zone Off Alaska; Several Groundfish Species in the Bering Sea and Aleutian Islands Management Area... the groundfish fishery in the (BSAI) exclusive economic zone according to the Fishery Management Plan... orderly conduct and efficient operation of this fishery, to allow the industry to plan for the...

  11. 78 FR 59908 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2013-09-30

    ... Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management Area; Amendment 99 AGENCY: National... more efficient vessels that are able to meet modern vessel safety standards. This action is intended to... review and comment. NMFS manages the U.S. groundfish fisheries of the Exclusive Economic Zone (EEZ)...

  12. 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...

  13. 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:...

  14. 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...

  15. 76 FR 66655 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod and Octopus in the Bering Sea...

    Science.gov (United States)

    2011-10-27

    ... Economic Zone Off Alaska; Pacific Cod and Octopus in the Bering Sea and Aleutian Islands Management Area... necessary to limit incidental catch of octopus by vessels using pot gear to fish for Pacific cod the BSAI... Act requires that conservation and management measures prevent overfishing. The 2011...

  16. 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.

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

    Science.gov (United States)

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

    2012-06-01

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

  18. 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

  19. 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 (< 4 km2), was preferred. This shows that walruses occupy ice patches with distinct ice features such as floe convexity, spatial density, and young ice and open 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

  20. 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℃.

  1. Temperature profile data collected using BT and XBT casts from NOAA Ship RESEARCHER and other platforms in the Bering Sea and other Sea areas from 1987-02-25 to 1987-07-27 (NCEI 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 NOAA Ship RESEARCHER and other platforms in the Bering Sea and other Sea areas from 25 February...

  2. 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...

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

    Data.gov (United States)

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

  4. A novel Chlamydiaceae-like bacterium found in faecal specimens from sea birds from the Bering Sea.

    Science.gov (United States)

    Christerson, Linus; Blomqvist, Maria; Grannas, Karin; Thollesson, Mikael; Laroucau, Karine; Waldenström, Jonas; Eliasson, Ingvar; Olsen, Björn; Herrmann, Björn

    2010-08-01

    The family Chlamydiaceae contains several bacterial pathogens of important human and veterinary medical concern, such as Chlamydia trachomatis and Chlamydophila psittaci. Within the order Chlamydiales there are also an increasing number of chlamydia-like bacteria whose biodiversity, host range and environmental spread seem to have been largely underestimated, and which are currently being investigated for their potential medical relevance. In this study we present 16S rRNA, rnpB and ompA gene sequence data congruently indicating a novel chlamydia-like bacterium found in faecal specimens from opportunistic fish-eating sea birds, belonging to the Laridae and Alcidae families, from the Bering Sea. This novel bacterium appears to be closer to the Chlamydiaceae than other chlamydia-like bacteria and is most likely a novel genus within the Chlamydiaceae family.

  5. 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 catches...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  8. 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....

  9. 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...

  10. 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...

  11. 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...

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

    Science.gov (United States)

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

    2016-07-01

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

  13. Aerial Surveys of Endangered Whales in the Beaufort Sea, Chukchi Sea, and Northern Bering Sea.

    Science.gov (United States)

    1981-06-01

    16 Surveys of St Lawrence Island Nome to Point Barrow . . . 16 I Surveys of Barrow Area . . 18 Point Barrow to Deadhorse . . . 20 Surveys from...lease area, the Norton Basin - St . Lawrence Island area, the Hope Basin, and coastal portions of the Chukchi Sea. DESIGN The areas of study are listed...Bowhead Whale 314 857 Balaena mysticetus Beluga Whale** 284 3404 Delphinapterus leucas Gray Whale 2 6 Eschrichtius robustus Ring Seal 250 765 Phoca

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  15. Late Quaternary sea-level changes and palaeoseismology of the Bering Glacier region, Alaska

    Science.gov (United States)

    Shennan, Ian

    2009-08-01

    Glacial isostatic adjustment and multiple earthquake deformation cycles produce temporal and spatial variability in the records of relative sea-level change across south-central Alaska. Bering Glacier had retreated inland of the present coast by 16 ka BP and north of its present terminus by ˜14 ka BP. Reconnaissance investigations in remote terrain provide new but limited insights of post-glacial relative sea-level change and the palaeoseismology of the region. Relative sea-level was above present ˜9.2 ka BP to at least 5 ka BP before falling to below present. It was above present by the early 20th century, before land uplift in the 1964 M 9.2 earthquake. The pattern of relative sea-level change differs what may be expected in comparison with model predictions for other seismic and non-seismic locations. Buried mud-peat couplets show a great earthquake ˜900 cal BP, including evidence of a tsunami. Correlation with other sites suggest simultaneous rupture of adjacent segments of the Aleutian megathrust and the Yakutat microplate.

  16. 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

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

    Science.gov (United States)

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

    2016-10-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Jin Meibing; Clara Deal; WANG Jia

    2008-01-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

  20. 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.

  1. Sea Surface Conditions during Marine Isotope Stages 12 to 10 at Navarin Canyon in the Bering Sea (IODP Site U1345)

    Science.gov (United States)

    Caissie, B.; Brigham-Grette, J.; Colmenero-Hidalgo, E.; Cook, M. S.; Mix, A. C.

    2012-12-01

    Records of terrestrial-marine coupling during past warming intervals are essential for understanding climate system dynamics. The Bering Sea is ideally situated to record how opening or closing the Pacific-Arctic ocean gateway (Bering Strait) impacts primary productivity, sea ice, and sediment transport and how these changes in the marine realm correspond with changes on the Bering land bridge. Very little is known about this region prior to 125 ka. IODP Expedition 323 to the Bering Sea offered an unparalleled chance to look in detail at time periods deeper than had previously been retrieved using gravity and piston cores. Here we look at the sea surface conditions at Site U1345, located near the shelf-slope break in the Bering Sea. We present an orbitally-tuned age model based on the oxygen isotopic composition of benthic foraminifera. We then focus in detail on the climate transitions during Marine Isotope Stages (MIS) 12 to 10 (435-365 ka). The site is near the marginal ice zone today and similarly experienced seasonal sea ice throughout both the glacial and interglacial stages, recorded as relatively high percentages of sea-ice related diatoms throughout the study interval. Diatom assemblage turnovers occur at 425 ka, 410 ka, 400 ka, and 377 ka, and reflect changes in upwelling, sea ice, glacial ice, and potentially even current direction. The diatom assemblage record, supported by calcareous nannofossil abundances, shows that MIS 11 is bracketed by highly productive laminated intervals. These laminated intervals are coeval with flooding of the Beringian shelf at 425 and 377 ka. Upwelling was robust during the termination laminations and MIS 10 laminations, and moderate during late MIS 11. Productivity increases in the Bering Sea occur coeval with high productivity pulses in the North Atlantic and may be related to sea level rise and flooding of Bering Strait. Beginning at approximately 410 ka, both insolation and obliquity began to decline and some mountainous

  2. On using numerical sea-ice prediction and indigenous observations to improve operational sea-ice forecasts during spring in the bering sea

    Science.gov (United States)

    Deemer, Gregory Joseph

    Impacts of a rapidly changing climate are amplified in the Arctic. The most notorious change has come in the form of record-breaking summertime sea-ice retreat. Larger areas of open water and a prolonged ice-free season create opportunity for some industries, but bring new challenges to indigenous populations that rely on sea-ice cover for subsistence. Observed and projected increases in maritime activities require accurate sea-ice forecasts on the weather timescale, which are currently lacking. Motivated by this need, this study explores how new modeling developments and local-scale observations can contribute to improving sea-ice forecasts. The Arctic Cap Nowcast/Forecast System, a research sea-ice forecast model developed by the U.S. Navy, is evaluated for forecast skill. Forecasts of ice concentration, thickness, and drift speed produced by the model from April through June 2011 in the Bering Sea were investigated to determine how the model performs relative to persistence and climatology. Results show that model forecasts can outperform forecasts based on climatology or persistence. However, predictive skill is less consistent during powerful, synoptic-scale events and near the Bering Slope. Forecast case studies in Western Alaska were presented. Community-based observations from recognized indigenous sea-ice experts have been analyzed to gauge the prospect of using local observations in the operational sea-ice monitoring and prediction process. Local observations were discussed in the context of cross-validating model guidance, data sources used in operational ice monitoring, and public sea-ice information products issued by the U.S. National Weather Service. Instrumentation for observing sea-ice and weather at the local scale was supplied to key observers. The instrumentation shows utility in the field and may help translate the context of indigenous observations and provide ground-truth data for use by forecasters.

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

    Science.gov (United States)

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

    2013-10-01

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

  4. 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.

  5. 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...

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

  8. Growth dynamics of saffron cod (Eleginus gracilis) and Arctic cod (Boreogadus saida) in the Northern Bering and Chukchi Seas

    Science.gov (United States)

    Helser, Thomas E.; Colman, Jamie R.; Anderl, Delsa M.; Kastelle, Craig R.

    2017-01-01

    Saffron cod (Eleginus gracilis) and Arctic cod (Boreogadus saida) are two circumpolar gadids that serve as critically important species responsible for energy transfer in Arctic food webs of the northern Bering and Chukchi Seas. To understand the potential effects of sea ice loss and warming temperatures on these species' basic life history, information such as growth is needed. Yet to date, limited effort has been dedicated to the study of their growth dynamics. Based on a large sample of otoliths collected in the first comprehensive ecosystem integrated survey in the northern Bering and Chukchi Seas, procedures were developed to reliably estimate age from otolith growth zones and were used to study the growth dynamics of saffron and Arctic cod. Annual growth zone assignment was validated using oxygen isotope signatures in otoliths and otolith morphology analyzed and compared between species. Saffron cod attained larger asymptotic sizes (L∞=363 mm) and achieved their maximum size at a faster rate (K=0.378) than Arctic cod (L∞=209 mm; K=0.312). For both species, regional differences in growth were found (pArctic cod grew to smaller asymptotic size but at faster rates in the more northerly central (L∞=197 mm;K=0.324) and southern Chukchi Sea (L∞=221 mm;K=0.297) when compared to the northern Bering Sea (L∞=266 mm;K=0.171), suggesting a possible cline in growth rates with more northerly latitudes. Comparison of growth to two periods separated by 30 years indicate that both species exhibited a decline in maximum size accompanied by higher instantaneous growth rates in more recent years.

  9. Preliminary study on particulate organic carbon export fluxes in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    Ma Hao; Zeng Zhi; He Jianhua; Yin Mingduan; Chen Liqi; Zeng Shi

    2009-01-01

    During the Second Chinese National Arctic Expedition (CHINARE) from July to September 2003, depth profiles of dissolved and particulate 234Th in upper water columns were collected at two stations of BR03 and BR24 in the Bering Sea. 234Th was sampled by using a traditional Fe(OH)3 co-precipitation technique, which is a reliable approach to 234Th measurement. We observed 234Th excess at station BR03 below the euphotic zone, which was possibly due to the intensive remineralization of particulate matter. Particulate organic carbon (POC) export fluxes were estimated from a one-dimensional irreversible steady state model of 234Th fluxes together with measurements of the POC/234Th ratio on the suspended particles. The POC export fluxes from the euphotic zone were 11.66 and 11.69 mmol C m-2 d-1 at BR03 and BR24 stations,respectively. The ratios of POC fluxes to primary production at the two stations were about 0.5 and 0.59, respectively, probably due to the presence of large phytoplankton (in particular diatoms).

  10. A comparison of ship and Coastal Zone Color Scanner mapped distribution of phytoplankton in the southeastern Bering Sea

    Science.gov (United States)

    Mcclain, C. R.; Sambrotto, R. N.; Ray, G. C.; Muller-Karger, F. E.

    1990-01-01

    Twenty-one Coastal Zone Color Scanner (CZCS) images of the southeastern Bering Sea are examined in order to map the near-surface distribution of phytoplankton during 1979 and 1980. The information is compared with the mesoscale (100-1000 km) distribution of phytoplankton inferred from pooled ship sampling obtained during the Processes and Resources of the Bering Shelf (PROBES) intensive field study during the late 1970s and early 1980s. The imagery indicates that open-water phytoplankton blooms occur first in late April in coastal waters, peak in early May over the middle shelf, and decay rapidly afterwards, reaching concentration minima in June in both regions. These patterns show that the earlier ship observations are valid for most of the eastern Bering shelf. A very tight correlation is found between the PROBES surface chlorophyll a concentrations and mean mixed-layer chlorophyll concentrations. The significant discrepancies between CZCS and ship-based chlorophyll estimates may be due to aliasing in time by the CZCS. It is concluded that neither satellite nor ship alone can do an adequate job of characterizing the physics or biological dynamics of the ocean.

  11. The fundamental characteristics of current in the Bering Strait and the Chukchi Sea from July to September 2003

    Institute of Scientific and Technical Information of China (English)

    LI Lei; DU Ling; ZHAO Jinping; ZUO Juncheng; LI Peiliang

    2005-01-01

    The characteristics of current in the Bering Strait and the Chukchi Sea are analyzed based on the two current data on the mooring stations during the Second National Arctic Research Expedition of China in 2003. The tidal currents of the principal diurnal and semidiurnal ellipses rotate clockwise in the upper layer, except for N2, S2, and Q1 at Sta. ST. In the Bering Strait (Sta. ST), the major semi-axis of tidal current constituent M2 is 2.9 cm/s in the upper layer, which is much smaller than that of semi-monthly oscillation (11.8 cm/s);and the mean current flows northwestward at the amplitude of about 20 cm/s and varies a little with depth. During the cruise, the current has significant semi-monthly oscillation at the two mooring stations. The spectra analyses of the air pressure gradient and the wind stress show that there are the semi-monthly oscillations in these two data series. The near-inertial current, approximately 4 cm/s, presents almost the same magnitude of the principal tidal currents in the Bering Strait.

  12. Assessment of high latitude variability and extreme events in the Bering Sea as simulated by a global climate model

    Science.gov (United States)

    Walston, Joshua M.

    Atmospheric and Oceanic observations of the Arctic and Subarctic are relatively sparse and hinder our ability to analyze short term variability and long-duration anomalies of physical and biological variables over decadal time scales. Earth System Models (ESM's), such as the Community Earth System Model (CESM1), represent a useful tool to advance the understanding and the predictive potential of large-scale shifts in the climate and climate related impacts. This thesis initially focuses on assessing the skill of the Community Climate System Model (CCSM4), to capture natural variability of the climate system. Subsequently, I examine the impacts of variability and seasonal-scale extremes of the physical environment on the marine ecosystem of the eastern Bering Sea as simulated by an earth system model, the CESM1, which includes the CCSM4 and earth system elements. A performance assessment of key atmospheric components (air temperature, sea level pressure, wind speed and direction) simulated by the CCSM4 over the Bering Sea and Arctic domains suggests a general improvement in model predictions at high latitudes relative to the model's predecessor, the CCSM3. However, several shortcomings, with possible implications for marine ecosystem modeling, still remain in this version of the CCSM. The most important of which includes an under-simulated Siberian High and a large northwest displacement of the Aleutian Low resulting in a negative bias of up to 8 hPa over the Bering Sea. The simulated inter-annual variability of surface air temperature and sea level pressure over the Bering Sea was found to exceed observed variability by ˜1.5 to 2 times. The displaced pressure systems and increased variability could have important ramifications for modeling efforts that use CCSM atmospheric output as drivers for marine ecosystem studies. When the CCSM was combined with other earth system elements to form the CESM, the coupled model was found to simulate strong linear relationships

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kyte, M.A.

    1977-06-16

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

  15. Changes in C37 alkenones flux on the eastern continental shelf of the Bering Sea: the record of Emiliania huxleyi bloom over the past 100 years

    Science.gov (United States)

    Harada, N.; Sato, M.; Okazaki, Y.; Oguri, K.; Tadai, O.; Saito, S.; Konno, S.; Jordan, R. W.; Katsuki, K.; Shin, K.; Narita, H.

    2008-12-01

    Flourishes of coccolithophores can be detected by ocean color imagery with data from the satellite-borne Sea-viewing Wide Field-of-view sensor SeaWiFs that was launched in 1997. Thus, temporally and spatially large-scale blooms of Emiliania huxleyi (E. huxleyi) have been distinguished annually in the eastern continental shelf of the Bering Sea since 1997. In 1997, a combination of atmospheric mechanisms produced summer weather anomalies such as calm winds, clear skies, and warm air temperature over the Bering Sea and the weather anomalies caused depletion of the subpycnocline nutrient reservoir (Napp and Hunt, 2001). After depletion of nitrate and silicate, a sustained (more than 4-month-long) bloom of E. huxleyi was observed (Stockwell et al., 2001). Because of the speed and magnitude with which parts of the Bering Sea ecosystem responded to changes in atmospheric factors (Napp and Hunt, 2001) and because a bloom of the coccolithophorid, Coccolithus pelagicus has also been detected in the northeastern Atlantic Ocean off Iceland every year since 1997 (Ostermann, 2001), the appearance of an E. huxleyi bloom in the Bering Sea could be related to atmospherically forced decadal oscillations or global factors. We have investigated spatial expansion and temporal development of E. huxleyi bloom on the continental shelf in the Bering Sea by using a biomarker of E. huxleyi, C37 alkenones flux recorded in the sediments during the past 100 years. As a result, the E. huxleyi bloom had been prominent since 1970"fs at latest during the last 100 years. In this presentation, we will discuss the relationship between E. huxleyi bloom and activity of Aleutian low, and also changes in diatom assemblages. References Napp and Hunt, 2001, Fish Oceanogr., 10, 61-68. Ostermann, 2001, WHOI annual report, pp.17-18. Stockwell et al., 2001, Fish Oceanogr., 10, 99-116.

  16. 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

  17. Juvenile Chinook Salmon abundance in the northern Bering Sea: Implications for future returns and fisheries in the Yukon River

    Science.gov (United States)

    Murphy, James M.; Howard, Kathrine G.; Gann, Jeanette C.; Cieciel, Kristin C.; Templin, William D.; Guthrie, Charles M.

    2017-01-01

    Juvenile Chinook Salmon (Oncorhynchus tshawytscha) abundance in the northern Bering Sea is used to provide insight into future returns and fisheries in the Yukon River. The status of Yukon River Chinook Salmon is of concern due to recent production declines and subsequent closures of commercial, sport, and personal use fisheries, and severe restrictions on subsistence fisheries in the Yukon River. Surface trawl catch data, mixed layer depth adjustments, and genetic stock mixtures are used to estimate juvenile abundance for the Canadian-origin stock group from the Yukon River. Abundance ranged from a low of 0.62 million in 2012 to a high of 2.58 million in 2013 with an overall average of 1.5 million from 2003 to 2015. Although abundance estimates indicate that average survival is relatively low (average of 5.2%), juvenile abundance was significantly correlated (r=0.87, p=0.005) with adult returns, indicating that much of the variability in survival occurs during early life-history stages (freshwater and initial marine). Juvenile abundance in the northern Bering Sea has increased since 2013 due to an increase in early life-history survival (average juveniles-per-spawner increased from 29 to 59). The increase in juvenile abundance is projected to produce larger runs and increased subsistence fishing opportunities for Chinook Salmon in the Yukon River as early as 2016.

  18. 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.

  19. Effects of lead structure in Bering Sea pack ice on the flight costs of wintering spectacled eiders

    Science.gov (United States)

    Bump, Joseph K.; Lovvorn, James R.

    2004-10-01

    In polar regions, sea ice is critical habitat for many marine birds and mammals. The quality of pack ice habitat depends on the duration and spacing of leads (openings in the ice), which determine access to water and air for diving endotherms, and how often and how far they must move as leads open and close. Recent warming trends have caused major changes in the extent and nature of sea ice at large scales used in climate models. However, no studies have analyzed lead structure in terms of habitat for ice-dependent endotherms, or effects of climate on ice habitat at scales relevant to their daily movements. Based on observations from an icebreaker and synthetic aperture radar (SAR) images, we developed methods to describe the dynamics and thermodynamics of lead structure relative to use by spectacled eiders ( Somateria fischeri) wintering in pack ice of the Bering Sea. By correlating lead structure with weather variables, we then used these methods to estimate changes in lead dynamics from 1945 to 2002, and effects of such changes on flight costs of the eiders. For 1991-1992, when images were available about every 3 days throughout winter, SAR images were divided among five weather regimes defined by wind speed, wind direction, and air temperature. Based on 12.5-m pixels, lead shape, compass orientation, and fetch across leads did not differ among the weather regimes. However, the five regimes differed in total area of open water, leads per unit area, and distance between leads. Lead duration was modeled based on air temperature, wind, and fetch. Estimates of mean daily flight time for eiders, based on lead duration and distance between neighboring leads, differed among regimes by 0 to 15 min. Resulting flight costs varied from 0 to 158 kJ day -1, or from 0% to 11% of estimated field metabolic rate. Over 57 winters (1945-2002), variation among years in mean daily flight time was most influenced by the north-south wind component, which determined pack divergence

  20. Trophic cascades and future harmful algal blooms within ice-free Arctic Seas north of Bering Strait: A simulation analysis

    Science.gov (United States)

    Walsh, John J.; Dieterle, Dwight A.; Chen, F. Robert; Lenes, Jason M.; Maslowski, Wieslaw; Cassano, John J.; Whitledge, Terry E.; Stockwell, Dean; Flint, Mikhail; Sukhanova, Irina N.; Christensen, John

    2011-11-01

    Within larger ice-free regions of the western Arctic Seas, subject to ongoing trophic cascades induced by past overfishing, as well as to possible future eutrophication of the drainage basins of the Yukon and Mackenzie Rivers, prior very toxic harmful algal blooms (HABs) - first associated with ∼100 human deaths near Sitka, Alaska in 1799 - may soon expand. Blooms of calcareous coccolithophores in the Bering Sea during 1997-1998 were non-toxic harbingers of the subsequent increments of other non-siliceous phytoplankton. But, now saxitoxic dinoflagellates, e.g. Alexandrium tamarense, were instead found by us within the adjacent downstream Chukchi Sea during SBI cruises of 2002 and 2003. A previous complex, coupled biophysical model had been validated earlier by ship-board observations from the Chukchi/Beaufort Seas during the summer of 2002. With inclusion of phosphorus as another chemical state variable to modulate additional competition by recently observed nitrogen-fixers, we now explore here the possible consequences of altered composition of dominant phytoplankton functional groups [diatoms, microflagellates, prymnesiophyte Phaeocystis colonies, coccolithophores, diazotrophs, and dinoflagellates] in relation to increases of the toxic A. tamarense, responding to relaxation of grazing pressure by herbivores north of Bering Strait as part of a continuing trophic cascade. Model formulation was guided by validation observations obtained during 2002-2004 from: cruises of the SBI, CHINARE, and CASES programs; moored arrays in Bering Strait; other RUSALCA cruises around Wrangel Island; and SBI helicopter surveys of the shelf-break regions of the Arctic basin. Our year-long model scenarios during 2002-2003 indicate that post bloom silica-limitation of diatoms, after smaller simulated spring grazing losses, led to subsequent competitive advantages in summer for the coccolithophores, dinoflagellates, and diazotrophs. Immediate top-down control is exerted by imposed

  1. Occurrence of polychlorinated biphenyls (PCBs) together with sediment properties in the surface sediments of the Bering Sea, Chukchi Sea and Canada Basin.

    Science.gov (United States)

    Hong, Qingquan; Wang, Yun; Luo, Xiaojun; Chen, Shejun; Chen, Jigang; Cai, Minghong; Cai, Minggang; Mai, Bixian

    2012-09-01

    The spatial distribution and potential source of polychlorinated biphenyls (PCBs) in surface sediments from Bering Sea, Chukchi Sea, and Canada Basin and the relationship between PCBs and sedimentary properties including grain size, water content, loss on ignition, total organic carbon, and black carbon were explored. ΣPCBs (the sum of the detected PCB congeners) concentrations fluctuated in the study area, ranging from 22-150, 60-640 and 24-600 pg g(-1) dry weight for the Bering Sea, Chukchi Sea, and Canada Basin. A similar homologue pattern was observed at different locations, with tri-chlorinated PCBs being the dominant homologue, implying that the PCBs came mainly from the atmospheric transportation and deposition and ocean current transportation. No apparent co-relationships between PCB concentrations and sediment properties were obtained, indicating that the distribution of PCBs was not only controlled by their source, but also by the multi-factors such as atmospheric transport and depositing, mixing, partitioning and sorption in the water column and sediments.

  2. Anthropogenic {sup 129}I in the North Pacific, Bering and Chukchi Seas, and Arctic Ocean in 2012–2013

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, H., E-mail: hnagai@chs.nihon-u.ac.jp [Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Hasegawa, A. [Graduate School of Integrated Basic Sciences, Nihon University, Tokyo 156-8550 (Japan); Yamagata, T. [Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Kumamoto, Y.; Nishino, S. [Japan Agency for Marine-Earth Science and Technology, Kanagawa 237-0061 (Japan); Matsuzaki, H. [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo 113-0032 (Japan)

    2015-10-15

    Most of anthropogenic {sup 129}I 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 {sup 129}I concentration in seawaters in the North Atlantic and Arctic Oceans to more than 10{sup 9} atoms L{sup −1}, which is two orders of magnitude higher than that in other region. Recently, in March 2011, a large quantity of {sup 129}I 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 {sup 129}I concentration in seawaters in the northern North Pacific Ocean, Bering and Chukchi Seas, and Arctic Ocean in 2012–2013. The {sup 129}I concentrations were 1.0–1.8 × 10{sup 7} atoms L{sup −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 {sup 129}I 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 {sup 129}I distribution in seawater in the North Pacific to the Chukchi Sea revealed no significant increase of {sup 129}I concentration caused by the F1NPP accident. The {sup 129}I concentrations were 13–14 × 10{sup 7} atoms L{sup −1} in surface waters and 80 × 10{sup 7} atoms L{sup −1} at depths of 300 and 800 m in the Arctic Ocean.

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    J.-R. Riethdorf

    2012-12-01

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

  5. A comparison between late summer 2012 and 2013 water masses, macronutrients, and phytoplankton standing crops in the northern Bering and Chukchi Seas

    Science.gov (United States)

    Danielson, Seth L.; Eisner, Lisa; Ladd, Carol; Mordy, Calvin; Sousa, Leandra; Weingartner, Thomas J.

    2017-01-01

    Survey data from the northern Bering and Chukchi sea continental shelves in August-September 2012 and 2013 reveal inter-annual differences in the spatial structure of water masses along with statistically significant differences in thermohaline properties, chemical properties, and phytoplankton communities. We provide a set of water mass definitions applicable to the northern Bering and Chukchi continental shelves, and we find that the near-bottom Bering-Chukchi Summer Water (BCSW) was more saline in 2012 and Alaskan Coastal Water (ACW) was warmer in 2013. Both of these water masses carried higher nutrient concentrations in 2012, supporting a larger chlorophyll a biomass that was comprised primarily of small (ice in winter and early spring in 2012 and 2013 resembled conditions of the 1980s and early 1990s but the regional ice retreat rate has accelerated in the late 1990s and 2000s so the summer and fall ice concentrations more closely resembled those of the last two decades. Our data show that wind forcing can shut down the Alaskan Coastal Current in the NE Chukchi Sea for periods of weeks to months during the ice-covered winter and during the summer when buoyancy forcing is at its annual maximum. We hypothesize that a decrease in salinity and nutrients from 2012 to 2013 was a consequence of a decreased net Bering Strait transport from 2011 to 2012. Biological ramifications of an accelerated ice melt-back, restructuring of shelf flow pathways, and inter-annually varying Bering Strait nutrient fluxes are mostly unknown but all of these variations are potentially important to the Arctic ecosystem. Our results have implications for the total magnitude and seasonal evolution of primary productivity, secondary production, and the fate of fresh water, heat, and pelagic production on the Bering-Chukchi shelves.

  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. 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....

  8. 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...

  9. 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...

  10. 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 -...

  11. 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...

  12. Epifaunal data from bottom trawls from NOAA Ship MILLER FREEMAN in the Bering Sea from 1979-07-07 TO 28 July 1979 in support of the Outer Continental Shelf Assessment Program (OCSEAP) (NODC Accession 0000451)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Epifuanal data were collected using bottom trawls from NOAA Ship Miller Freeman in the Bering Sea from 07 July 1979 TO 28 July 1979. Data were collected as part of...

  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 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...

  14. 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 spatio-temporal...

  15. 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...

  16. 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...

  17. 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...

  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. 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...

  20. 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...

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

    Data.gov (United States)

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

  2. 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...

  3. 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...

  4. Temperature and Salinity Profile Data Collected from the Bering Sea in Support of the Inner Shelf Transfer and Recycling Project from from 15 September 1985 to 22 September 1985 (NODC Accession 0000414)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD and other data were collected from the Bering Sea from the ALPHA HELIX from 15 September 1985 to 22 September 1985. Data were collected by the University of...

  5. 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...

  6. 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...

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

    Data.gov (United States)

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

  8. 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...

  9. 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,...

  10. 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,...

  11. 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,...

  12. 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,...

  13. 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...

  14. Oceanographic profile data collected from CTD casts aboard NOAA Ship FAIRWEATHER as part of project OPR-R976-FA-15 in the Bering Sea from 2015-06-16 to 2015-09-04 (NCEI Accession 0138579)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0138579 includes physical and profile data collected aboard NOAA Ship FAIRWEATHER during project OPR-R976-FA-15 in the Bering Sea from 2015-06-16 to...

  15. 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...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  19. 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...

  20. Marine mammal and other data from aircraft in the Bering Sea and other locations as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 10 June 1975 to 18 June 1976 (NODC Accession 7700222)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal and other data were collected from aircraft in the Bering Sea and other locations from 10 June 1975 to 18 June 1976. Data were collected by the Alaska...

  1. 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...

  2. 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...

  3. Oceanographic profile data collected from CTD casts aboard FA2806 and NOAA Ship FAIRWEATHER as part of project OPR-Q328-FA-15 in the Bering Sea on 2015-07-08 (NCEI Accession 0130934)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0130934 includes physical and profile data collected aboard the FA2806 and NOAA Ship FAIRWEATHER during project OPR-Q328-FA-15 in the Bering Sea on...

  4. 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...

  5. 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...

  6. Biological, chemical and other data collected aboard the THOMAS G. THOMPSON during cruise TN249 in the Bering Sea from 2010-05-10 to 2010-06-15 (NODC Accession 0117397)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0117397 includes biological, chemical, optical and physical data collected aboard the THOMAS G. THOMPSON during cruise TN249 in the Bering Sea from...

  7. 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...

  8. Physical, current, and other data from CTD and current meters from FIXED PLATFORMS in the Bering Sea in support of the Fisheries-Oceanography Coordinated Investigations (FOCI) project from 25 February 1998 to 10 October 2001 (NODC Accession 0000665)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, current, and other data from CTD and current meters from FIXED PLATFORMS in the Bering Sea from 25 February 1998 to 10 October 2001. Data were collected by...

  9. Current, pressure gauge, and other data from instruments attached to fixed platforms in the Bering Sea as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 16 September 1977 to 20 September 1978 (NODC Accession 8000024)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current, pressure gauge, and other data were collected from instruments attached to fixed platforms in the Bering Sea from the 16 September 1977 to 20 September...

  10. 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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

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

    Science.gov (United States)

    Walsh, John J.; Dieterle, Dwight A.

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

  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 CO2 and iron availability on rbcL gene expression in Bering Sea diatoms

    Science.gov (United States)

    Endo, H.; Sugie, K.; Yoshimura, T.; Suzuki, K.

    2015-04-01

    Iron (Fe) can limit phytoplankton productivity in approximately 40% of the global ocean, including in high-nutrient, low-chlorophyll (HNLC) waters. However, there is little information available on the impact of CO2-induced seawater acidification on natural phytoplankton assemblages in HNLC regions. We therefore conducted an on-deck experiment manipulating CO2 and Fe using Fe-deficient Bering Sea water during the summer of 2009. The concentrations of CO2 in the incubation bottles were set at 380 and 600 ppm in the non-Fe-added (control) bottles and 180, 380, 600, and 1000 ppm in the Fe-added bottles. The phytoplankton assemblages were primarily composed of diatoms followed by haptophytes in all incubation bottles as estimated by pigment signatures throughout the 5-day (control) or 6-day (Fe-added treatment) incubation period. At the end of incubation, the relative contribution of diatoms to chlorophyll a biomass was significantly higher in the 380 ppm CO2 treatment than in the 600 ppm treatment in the controls, whereas minimal changes were found in the Fe-added treatments. These results indicate that, under Fe-deficient conditions, the growth of diatoms could be negatively affected by the increase in CO2 availability. To further support this finding, we estimated the expression and phylogeny of rbcL (which encodes the large subunit of RuBisCO) mRNA in diatoms by quantitative reverse transcription polymerase chain reaction (PCR) and clone library techniques, respectively. Interestingly, regardless of Fe availability, the transcript abundance of rbcL decreased in the high CO2 treatments (600 and 1000 ppm). The present study suggests that the projected future increase in seawater pCO2 could reduce the RuBisCO transcription of diatoms, resulting in a decrease in primary productivity and a shift in the food web structure of the Bering Sea.

  15. 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.

  16. 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...

  17. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Arctic Ocean, Beaufort Sea and Bering Sea from 2000-08-03 to 2000-10-13 (NODC Accession 0112352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112352 includes chemical, discrete sample, physical and profile data collected from MIRAI in the Arctic Ocean, Beaufort Sea and Bering Sea from...

  18. 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...

  19. 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 Pacific...

  20. Composition of fish species in the Bering and Chukchi Seas and their responses to changes in the ecological environment

    Institute of Scientific and Technical Information of China (English)

    LIN Longshan; CHEN Yongjun; LIAO Yunchih; ZHANG Jing; SONG Puqing; YU Xingguang; WU Risheng; SHAO Kwang-tsao

    2014-01-01

    Based on trawl surveys in the Bering Sea and Chukchi Sea during the 2010 Chinese National Arctic Research Expedition, fish biodiversity characteristics, such as fish composition, dominant species, biodiversity, and faunal characteristics were conducted. We also discussed the responses of fishes to the quick changes in Arctic climate. The results showed that a total of 41 species in 14 families were recorded in these waters. The dominant species were Hippoglossoides robustus, Boreogadus saida, Myoxocephalus scorpius, Lumpenus fa-bricii, and Artediellus scaber. There were 35 coldwater species, accounting for 85.37%, and six cold temperate species, occupying 14.63%. The habitat types of fish could be grouped as follows:35 species of demersal fish-es, five benthopelagic fishes, and one pelagic fish. The Shannon-Wiener diversity index (H′) (range between 0 and 2.18, 1.21 on average) was not high, and descended from south to north. Climate change has caused some fishes to shift along their latitudinal and longitudinal distribution around the Arctic and Subarctic areas, and this could lead to the decline of Arctic fishery resources.

  1. 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.

  2. 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.

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

    Science.gov (United States)

    Wang, Jun; Hülck, Kathrin; Hong, Su-Myeong; Atkinson, Shannon; Li, Qing X

    2011-01-01

    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 [corrected] 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 [corrected] suggesting the possibility of adverse effects on this stock.

  4. 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....

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Science.gov (United States)

    Talbot, Sandra; Sage, Kevin; Rearick, Jolene; Fowler, Megan C.; Muñiz-Salazar, Raquel; Baibak, Bethany; Wyllie-Echeverria, Sandy; Cabello-Pasini, Alehandro; Ward, David H.

    2016-01-01

    Eelgrass (Zostera marina) populations occupying coastal waters of Alaska are separated by a peninsula and island archipelago into two Large Marine Ecosystems (LMEs). From populations in both LMEs, we characterize genetic diversity, population structure, and polarity in gene flow using nuclear microsatellite fragment and chloroplast and nuclear sequence data. An inverse relationship between genetic diversity and latitude was observed (heterozygosity: R2 = 0.738, P < 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.

  7. Bidecadal variability in the Bering Sea and the relation with 18.6 year period nodal tidal cycle

    Science.gov (United States)

    Osafune, S.; Yasuda, I.

    2010-02-01

    Bidecadal variations are investigated in the Bering Sea, especially in the southeastern basin adjacent to the Aleutian passes, where vertical mixing may be strong because of the diurnal tide. Those variations found in this region are synchronized with the 18.6 year period nodal tidal cycle, and the temporal patterns are similar to ones around the northwestern subarctic Pacific near the Kuril Straits reported by a previous study. Salinity and density in the upper layer are high in the periods when the diurnal tide is strong. In the intermediate layer, layer thickness is large, and isopycnal potential temperature and apparent oxygen utilization are low in the same periods. It is shown that these variations are consistent with the patterns expected from the nodal modulation of vertical mixing, and a simple two-dimensional model, assuming a balance between anomalous vertical mixing and advection of anomaly by the mean current, succeeds to some extent in explaining the variations of the upper layer salinity and isopycnal temperature and apparent oxygen utilization in the intermediate layer.

  8. 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

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

    Science.gov (United States)

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

    2015-01-01

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

  10. 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.

  11. Proximate composition, energetic value, and relative abundance of prey fish from the inshore eastern Bering Sea: Implications for piscivorous predators

    Science.gov (United States)

    Ball, J.R.; Esler, Daniel; Schmutz, J.A.

    2007-01-01

    Changing ocean conditions and subsequent shifts in forage fish communities have been linked to numerical declines of some piscivorous marine birds and mammals in the North Pacific. However, limited information about fish communities is available for some regions, including nearshore waters of the eastern Bering Sea, where many piscivores reside. We determined proximate composition and energetic value of a suite of potential forage fish collected from an estuary on the Yukon-Kuskokwim Delta, Alaska, during 2002 and 2003. Across species, energy density ranged from 14.5 to 20.7 kJ g−1 dry mass and varied primarily as a function of lipid content. Total energy content was strongly influenced by body length and we provide species-specific predictive models of total energy based on this relationship; some models may be improved further by incorporating year and date effects. Based on observed energetic differences, we conclude that variation in fish size, quantity, and species composition of the prey community could have important consequences for piscivorous predators.

  12. 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.

  13. 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.

  14. 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...

  15. 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...

  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 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...

  17. 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...

  18. 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...

  19. 50 CFR 600.1103 - Bering Sea and Aleutian Islands (BSAI) Crab species program.

    Science.gov (United States)

    2010-10-01

    ... purpose, to finance 100 percent of the reduction cost. The original principal amount of the reduction loan... limited to, fishing on the high seas or in the jurisdiction of any foreign country (to the...

  20. Fluorescence, pigment and microscopic characterization of Bering Sea phytoplankton community structure and photosynthetic competency in the presence of a Cold Pool during summer

    Science.gov (United States)

    Goes, Joaquim I.; Gomes, Helga do Rosario; Haugen, Elin M.; McKee, Kali T.; D'Sa, Eurico J.; Chekalyuk, Alexander M.; Stoecker, Diane K.; Stabeno, Phyllis J.; Saitoh, Sei-Ichi; Sambrotto, Raymond N.

    2014-11-01

    Spectral fluorescence measurements of phytoplankton chlorophyll a (Chl a), phytoplankton phycobilipigments and variable fluorescence (Fv/Fm), are utilized with High Performance Liquid Chromatography (HPLC) estimates of phytoplankton pigments and microscopic cells counts to construct a comprehensive picture of summer-time phytoplankton communities and their photosynthetic competency in the eastern Bering Sea shelf. Although the Bering Sea was ice-free during our study, the exceptionally cold winter that preceded the summer of 2008 when our cruise took place, facilitated the formation of a "Cold Pool" (<2 °C) and its entrapment at depth in the northern middle shelf. The presence of a strong pycnocline over the entire middle and outer shelves restricted inorganic nutrient fluxes into the surface waters resulting in phytoplankton populations that were photo-physiologically stressed due to nutrient limitation. Elevated Chl a concentrations recorded in the Green Belt along the shelf edge of the Bering Sea, were due to Phaeocystis pouchetii and nano-sized cryptophytes. Although inorganic nutrients were not limiting in the Green Belt, Fv/Fm values were low in all probability due to iron limitation. Phytoplankton communities in the low biomass surface waters of the middle shelf were comprised of prasinophytes, haptophytes, cryptophytes and diatoms. In the northern part of the middle shelf, a sinking bloom made up of the centric diatoms Chaeotoceros socialis, Thalassiosira nordenskioeldii and Porosira glacialis was located above the Cold Pool. The high biomass associated with this senescent bloom and its accretion above the pycnocline, suggests that the Cold Pool acts as a barrier, preventing sinking phytoplankton from reaching the bottom where they can become available to benthic organisms. We further posit that if summer-time storms are not energetic enough and the Cold Pool is not eroded, its presence facilitates the transfer of the large spring phytoplankton bloom to

  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. New Method for the Quantitative Analysis of Smear Slides in Pelagic and Hemi-Pelagic Sediments of the Bering Sea

    Science.gov (United States)

    Drake, M. K.; Aiello, I. W.; Ravelo, A. C.

    2014-12-01

    Petrographic microscopy of smear slides is the standard method to initially investigate marine sediments in core sediment studies (e.g. IODP expeditions). The technique is not commonly used in more complex analysis due to concerns over the subjectivity of the method and variability in operator training and experience. Two initiatives sponsored by Ocean Leadership, a sedimentology training workshop and a digital reference of smear slide components (Marsaglia et al., 2013) have been implemented to address the need for advanced training. While the influence of subjectivity on the quality of data has yet to be rigorously tested, the lack of standardization in the current method of smear slide analysis (SSA) remains a concern. The relative abundance of the three main components, (total diatoms, silt-to-sand sized siliciclastics, and clay minerals) of high and low density Bering Sea hemi-pelagic sediments from the ocean margin (Site U144; Site U1339) and pelagic sediments from the open-ocean (Site U1340) were analyzed. Our analyses show visual estimation is a reproducible method to quantify the relative abundance of the main sediment components. Furthermore, we present a modified method for SSA, with procedural changes objectively guided by statistical analyses, including constraints to increase randomness and precision in both the preparation and analysis of the smear slide. For example, repeated measure ANOVAs found a smear slide could be accurately quantified by counting three fields of view. Similarly, the use of replicate smear slides to quantify a sample was analyzed. Finally, the data produced from this modified SSA shows a strong correlation to continuously logged physical parameters of sediment such as gamma ray attenuation (Site U1339 r2= 0.41; Site U1340 r2= 0.36). Therefore, the modified SSA combined with other independent methods (e.g. laser particle size analysis, scanning electron microscopy, and physical properties) can be a very effective tool for the

  3. Coastal Environment, Bathymetry and Physical Oceanography along the Beaufort, Chukchi and Bering Seas.

    Science.gov (United States)

    1980-01-01

    fic 16 in th soute Shund.h A Sea reat a rdepth iemtr.Nmesrdct nortund along the Auasban shore wrist " a velt .f Here knt r rets rat ren veliy in caee 1...Area 6 Wave height/period PI. R-FC 12 --o.- . ........... 1 .- 2 C 0 S t 41 3%~ 0 -057 3io 0, Q; 0. . 1 X :’l NNN._ -. f " .~0 1 2 0. 0 .2 0 SLAC ME* 6

  4. 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

  5. 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.

  6. Climate change, pink salmon, and the nexus between bottom-up and top-down forcing in the subarctic Pacific Ocean and Bering Sea.

    Science.gov (United States)

    Springer, Alan M; van Vliet, Gus B

    2014-05-06

    Climate change in the last century was associated with spectacular growth of many wild Pacific salmon stocks in the North Pacific Ocean and Bering Sea, apparently through bottom-up forcing linking meteorology to ocean physics, water temperature, and plankton production. One species in particular, pink salmon, became so numerous by the 1990s that they began to dominate other species of salmon for prey resources and to exert top-down control in the open ocean ecosystem. Information from long-term monitoring of seabirds in the Aleutian Islands and Bering Sea reveals that the sphere of influence of pink salmon is much larger than previously known. Seabirds, pink salmon, other species of salmon, and by extension other higher-order predators, are tightly linked ecologically and must be included in international management and conservation policies for sustaining all species that compete for common, finite resource pools. These data further emphasize that the unique 2-y cycle in abundance of pink salmon drives interannual shifts between two alternate states of a complex marine ecosystem.

  7. 40Ar-39Ar dating and tectonic implications of volcanic rocks recovered at IODP Hole U1342A and D on Bowers Ridge, Bering Sea

    Science.gov (United States)

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

    2016-03-01

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

  8. 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 from...

  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. 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...

  11. Fatty acid and stable isotope characteristics of sea ice and pelagic particulate organic matter in the Bering Sea: tools for estimating sea ice algal contribution to Arctic food web production.

    Science.gov (United States)

    Wang, Shiway W; Budge, Suzanne M; Gradinger, Rolf R; Iken, Katrin; Wooller, Matthew J

    2014-03-01

    We determined fatty acid (FA) profiles and carbon stable isotopic composition of individual FAs (δ(13)CFA values) from sea ice particulate organic matter (i-POM) and pelagic POM (p-POM) in the Bering Sea during maximum ice extent, ice melt, and ice-free conditions in 2010. Based on FA biomarkers, differences in relative composition of diatoms, dinoflagellates, and bacteria were inferred for i-POM versus p-POM and for seasonal succession stages in p-POM. Proportions of diatom markers were higher in i-POM (16:4n-1, 6.6-8.7%; 20:5n-3, 19.6-25.9%) than in p-POM (16:4n-1, 1.2-4.0%; 20:5n-3, 5.5-14.0%). The dinoflagellate marker 22:6n-3/20:5n-3 was highest in p-POM. Bacterial FA concentration was higher in the bottom 1 cm of sea ice (14-245 μg L(-1)) than in the water column (0.6-1.7 μg L(-1)). Many i-POM δ(13)C(FA) values were higher (up to ~10‰) than those of p-POM, and i-POM δ(13)C(FA) values increased with day length. The higher i-POM δ(13)C(FA) values are most likely related to the reduced dissolved inorganic carbon (DIC) availability within the semi-closed sea ice brine channel system. Based on a modified Rayleigh equation, the fraction of sea ice DIC fixed in i-POM ranged from 12 to 73%, implying that carbon was not limiting for primary productivity in the sympagic habitat. These differences in FA composition and δ(13)C(FA) values between i-POM and p-POM will aid efforts to track the proportional contribution of sea ice algal carbon to higher trophic levels in the Bering Sea and likely other Arctic seas.

  12. 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.

  13. Marine-entry timing and growth rates of juvenile Chum Salmon in Alaskan waters of the Chukchi and northern Bering seas

    Science.gov (United States)

    Vega, Stacy L.; Sutton, Trent M.; Murphy, James M.

    2017-01-01

    Climate change in the Arctic has implications for influences on juvenile Chum Salmon Oncorhynchus keta early life-history patterns, such as altered timing of marine entry and/or early marine growth. Sagittal otoliths were used to estimate marine entry dates and daily growth rates of juvenile Chum Salmon collected during surface trawl surveys in summers 2007, 2012, and 2013 in the Chukchi and northern Bering seas. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to discriminate between freshwater and marine sagittal growth on the otoliths, and daily growth increments were counted to determine marine-entry dates and growth rates to make temporal and regional comparisons of juvenile Chum Salmon characteristics. Marine-entry dates ranged from mid-June to mid-July, with all region and year combinations exhibiting similar characteristics in entry timing (i.e. larger individuals at the time of capture entered the marine environment earlier in the growing season than smaller individuals in the same region/year), as well as similar mean marine-entry dates. Juvenile Chum Salmon growth rates were on average 4.9% body weight per day in both regions in summers 2007 and 2012, and significantly higher (6.8% body weight per day) in the Chukchi Sea in 2013. These results suggest that juvenile Chum Salmon in the northern Bering and Chukchi seas currently exhibit consistent marine-entry timing and early marine growth rates, despite some differences in environmental conditions between regions and among years. This study also provides a baseline of early marine life-history characteristics of Chum Salmon for comparisons with future climate change studies in these regions.

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

    Science.gov (United States)

    Husum, Katrine

    2016-03-01

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

  15. 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...

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

    Data.gov (United States)

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

  17. 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 by...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  20. 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...

  1. 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....

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

    Data.gov (United States)

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

  3. Pressure gauge 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 1983-08-04 to 1983-09-20 (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 NOAA Ship DISCOVERER and other platforms from 04 August 1983 to 20 September 1983. Data...

  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 NOAA Ship 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 NOAA Ship OSCAR DYSON in the Bering Sea, Gulf of Alaska and North Pacific Ocean from 2014-03-03...

  5. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Bering Sea and North Pacific Ocean from 2004-08-07 to 2004-08-30 (NODC Accession 0113609)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113609 includes chemical, discrete sample, physical and profile data collected from MIRAI in the Bering Sea and North Pacific Ocean from 2004-08-07...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  8. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea and other locations from NOAA Ship DISCOVERER as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1975-08-12 to 1975-10-15 (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 NOAA Ship DISCOVERER. Data were...

  9. 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...

  10. 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...

  11. 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...

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

    Data.gov (United States)

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

  13. 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...

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

    Data.gov (United States)

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

  15. Oceanographic profile data collected from CTD and sound velocimeter - moving vessel profiler casts aboard NOAA Ship 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 NOAA Ship FAIRWEATHER during project M-R908-FA-08 in the Bering Sea and North Pacific...

  16. Oceanographic profile data collected from CTD and sound velocimeter - moving vessel profiler casts aboard NOAA Ship 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 NOAA Ship FAIRWEATHER during project OPR-R365-FA-10 in the Bering Sea, Coastal Waters of...

  17. 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...

  18. Fish survey, fishing duration, and other data from net trawls in the Bering Sea from NOAA Ship MILLER FREEMAN and other platforms as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1976-04-01 to 1976-08-09 (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 NOAA Ship MILLER FREEMAN and other platforms from 01 April 1976...

  19. 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...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  2. Aerial surveys of endangered cetaceans and other marine mammals in the northwestern Gulf of Alaska and southeastern Bering Sea. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Brueggeman, J.J.; Green, G.A.; Grotefendt, R.A.; Chapman, D.G.

    1987-09-01

    Aerial surveys were conducted in the Northwestern Gulf of Alaska and southeastern Bering Sea to determine the abundance, distribution, and habitat use patterns of endangered cetaceans and other marine mammals. Four species of cetaceans listed by the Federal Government as endangered were observed: gray, humpback, finback, and sperm whales. Sightings were also made to seven nonendangered species of cetaceans: minke, Cuvier's beaked, Baird's beaked, belukha, and killer whales, and Dall and harbor porpoises. Results show that the project area is an important feeding ground for relatively large numbers of humpback and finback whales and lower numbers of gray whale migration route between seasonal ranges. The project area also supports a variety of other marine mammals both seasonally and annually.

  3. Aerial Surveys of Endangered Whales in the Northern Bering, Eastern Chukchi, and Alaskan Beaufort Seas, 1985: With a Seven Year Review, 1979-85.

    Science.gov (United States)

    1986-08-01

    8217 . " - • " " " ’ " ’"" . - - - " "" "° " " "" " " , , - " UUSS USSRA as LEGENDJ 0GV S CAPE PRINCE OF WALES % .4(DO crnM BERING SEA OCG 00 M 0a hI)rO 0 0 0 1 Kp 000...o,,o_.._ .- Demarcation Pt Cape Lisbuneo 680I , ialn 680: 660 USSR16 100 15 1 apatocni Prince of Wales AndSK i nest coe s dNo o i 64...and migration patterns of the white whale ( Beluga ), Delphinapterus leucas. Rep. int. Whal. Commn. vol. 30:465-480. 1980. Herzing, D.L. and B.R. Mate

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

    Science.gov (United States)

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

    2016-10-01

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

  5. 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 (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.

  6. Twentieth century δ13C variability in surface water dissolved inorganic carbon recorded by coralline algae in the northern North Pacific Ocean and the Bering Sea

    Directory of Open Access Journals (Sweden)

    W. Adey

    2010-07-01

    Full Text Available Oxygen isotopes and Mg/Ca ratios in long-lived coralline algae record ambient seawater temperature in their calcified tissues over time. Similarly, carbon stable isotopes (δ13C in the calcified tissue may record δ13C values of ambient seawater dissolved inorganic carbon. Here, we measured δ13C in the coralline algae Clathromorphum nereostratum to test the feasibility of reconstructing the intrusion of anthropogenic CO2 into the northern North Pacific Ocean and Bering Sea. δ13C was measured in the high Mg-calcite calcified tissue of three C. nereostratum specimens from two islands 500 km apart in the Aleutian archipelago. In the records spanning 1887 to 2003, the average rate of decline in δ13C values increased from 0.03‰ yr−1 in the 1960s to 0.1‰ yr−1 in the 1990s, which was higher than expected due to solely the δ13C-Suess effect. Deeper water in this region exhibits higher concentrations of CO2 and low δ13C values. Transport of deeper water into surface water (i.e., upwelling is increased when the Aleutian Low is intensified. We hypothesize that the acceleration of δ13C decline may result from an increase in upwelling from the 1960s to 1990s, which in turn was driven by an increase in the intensity of the Aleutian Low. Detrended δ13C records also vary on 4–7 years and bidecadal timescales supporting an atmospheric teleconnection of tropical climate patterns to the northern North Pacific Ocean and Bering Sea manifested as changes in upwelling.

  7. Twentieth century δ13C variability in surface water dissolved inorganic carbon recorded by coralline algae in the northern North Pacific Ocean and the Bering Sea

    Directory of Open Access Journals (Sweden)

    W. Adey

    2011-01-01

    Full Text Available The oxygen isotopic composition and Mg/Ca ratios in the skeletons of long-lived coralline algae record ambient seawater temperature over time. Similarly, the carbon isotopic composition in the skeletons record δ13C values of ambient seawater dissolved inorganic carbon. Here, we measured δ13C in the coralline alga Clathromorphum nereostratum to test the feasibility of reconstructing the intrusion of anthropogenic CO2 into the northern North Pacific Ocean and Bering Sea. The δ13C was measured in the high Mg-calcite skeleton of three C. nereostratum specimens from two islands 500 km apart in the Aleutian archipelago. In the records spanning 1887 to 2003, the average decadal rate of decline in δ13C values increased from 0.03‰ yr−1 in the 1960s to 0.095‰ yr−1 in the 1990s, which was higher than expected due to solely the δ13C-Suess effect. Deeper water in this region exhibits higher concentrations of CO2 and low δ13C values. Transport of deeper water into surface water (i.e., upwelling increases when the Aleutian Low is intensified. We hypothesized that the acceleration of the δ13C decline may result from increased upwelling from the 1960s to 1990s, which in turn was driven by increased intensity of the Aleutian Low. Detrended δ13C records also varied on 4–7 year and bidecadal timescales supporting an atmospheric teleconnection of tropical climate patterns to the northern North Pacific Ocean and Bering Sea manifested as changes in upwelling.

  8. Characteristics of Sound speed profile in Bering Sea in Summer%夏季白令海声速剖面分布特征

    Institute of Scientific and Technical Information of China (English)

    高飞; 潘长明; 冯盼盼; 王璐华; 王本洪; 李璨

    2014-01-01

    利用中国第5次北极科学考察CTD数据,分析了白令海夏季声速剖面结构特征。对比Chen-Millero、Delgrosso、Wilson 3种声速计算方法,其中Chen-Millero方法计算的声速值居中。将白令海夏季声速剖面结构总结为5类。其中白令海盆区域,受次表层低声速水团影响,夏季声速从表层向下先减小后增大,双跃层结构明显,南北差异较大,主声跃层位于133~200 m,强度在0.38 S-1左右,季节跃层强度约为-0.77 S-1;海盆向陆架过渡区域,声速水平变化剧烈;白令海峡以南受不同性质海流的影响,西南部声速比东南部小、跃层强,强度分别为-2.4 S-1、-2.0 S-1;9月份陆架海区表层声速开始减小,从表层向下声速先减小后增大。%Basedonthe surveying conductivity-temperature-depth (CTD) data by Chinese FifthArctic Research Expedition, the analysis of the characteristics of sound speed profiles structure in Bering Sea is conducted. By comparing three sound speed calculation methods of Chen-Millero、 Delgrosso and Wilson, the results of Chen-Millero is testified to be moderate. The sound speed profiles in Bering Sea are classified into 5 species. The Bering Sea basin is influenced by the low sound speed water mass in the subsurface layer, the sound speed value decreases first, and then increases in summer. Moreover, the double thermocline phenomena is obvious, and the difference between north and south is very apparent. Permanent thermocline exists in 133~200 m, the average intensity of which is 0.38 S-1. And the intensity of seasonal thermocline is about-0.77 S-1. In the transition zone from basin to shelf, the sound speed changes rapidly;The sound speed in the southwest of the Bering Strait is higher than in the southeast with the effects of different currents. However the intensity of thermocline is quite the contrary, which are-2.4 S-1 and-2.0 S-1, respectively. The sound speed firstly decreases in the

  9. Distribution of detrital minerals and sediment color in western Arctic Ocean and northern Bering Sea sediments: Changes in the provenance of western Arctic Ocean sediments since the last glacial period

    Science.gov (United States)

    Kobayashi, Daisuke; Yamamoto, Masanobu; Irino, Tomohisa; Nam, Seung-Il; Park, Yu-Hyeon; Harada, Naomi; Nagashima, Kana; Chikita, Kazuhisa; Saitoh, Sei-Ichi

    2016-12-01

    This paper describes the distribution of detrital minerals and sediment color in the surface sediments of the western Arctic Ocean and the northern Bering Sea and investigates the relationship between mineral composition and sediment provenance. This relationship was used to determine the provenance of western Arctic Ocean sediments deposited during the last glacial period. Sediment color is governed by water depth, diagenesis, and mineral composition. An a*-b* diagram was used to trace color change during diagenesis in the Arctic Ocean sediments. The mineral composition of surface sediments is governed by grain size and provenance. The feldspar/quartz ratio of the sediments studied was higher on the Siberian side than on the North American side of the western Arctic Ocean. The (chlorite + kaolinite)/illite and chlorite/illite ratios were high in the Bering Sea but decrease northwards in the Chukchi Sea. Thus, these ratios are useful for provenance studies in the Chukchi Sea area as indices of the Beaufort Gyre circulation and the Bering Strait inflow. The sediments deposited during the last glacial period have a lower feldspar/quartz ratio and a higher dolomite intensity than Holocene sediments on the Chukchi Plateau, suggesting a greater contribution of North American grains during the last glacial period.

  10. 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

  11. Ecology of Juvenile Walleye Pollock, Theragra chalcogramma: Papers from the workshop "The Importance of Prerecruit Walleye Pollock to the Bering Sea and North Pacific Ecosystems" Seattle, Washington, 28-30 October 1993

    OpenAIRE

    1996-01-01

    The Alaska Fisheries Science Center (AFSC), National Marine Fisheries Service (NMFS), hosted an international workshop, 'The Importance of Prerecruit Walleye Pollock to the Bering Sea and North Pacific Ecosystems," from 28 to 30 October 1993. This workshop was held in conjunction with the annual International North Pacific Marine Science Organization (PICES) meeting held in Seattle. Nearly 100 representatives from government agencies, universities, and the fishing industry in Canada, Ja...

  12. 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.

  13. 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

  14. 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...

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

    Science.gov (United States)

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

    2015-12-01

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

  16. Shipborne observations of atmospheric black carbon aerosol particles over the Arctic Ocean, Bering Sea, and North Pacific Ocean during September 2014

    Science.gov (United States)

    Taketani, Fumikazu; Miyakawa, Takuma; Takashima, Hisahiro; Komazaki, Yuichi; Pan, Xiaole; Kanaya, Yugo; Inoue, Jun

    2016-02-01

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

  17. The relationship between pink salmon biomass and the body condition of short-tailed shearwaters in the Bering Sea: can fish compete with seabirds?

    Science.gov (United States)

    Toge, Kanako; Yamashita, Rei; Kazama, Kentaro; Fukuwaka, Masaaki; Yamamura, Orio; Watanuki, Yutaka

    2011-09-07

    Seabirds and large fishes are important top predators in marine ecosystems, but few studies have explored the potential for competition between these groups. This study investigates the relationship between an observed biennial change of pink salmon (Oncorhynchus gorbuscha) biomass in the central Bering Sea (23 times greater in odd-numbered than in even-numbered years) and the body condition and diet of the short-tailed shearwater (Puffinus tenuirostris) that spends the post-breeding season there. Samples were collected with research gill nets over seven summers. Both species feed on krill, small fishes and squid. Although the mean pink salmon catch per unit effort (in mass) over the study region was not related significantly with shearwater's stomach content mass or prey composition, the pink salmon biomass showed a negative and significant relationship with the shearwater's body mass and liver mass (proxies of energy reserve). We interpret these results as evidence that fishes can negatively affect mean prey intake of seabirds if they feed on a shared prey in the pelagic ecosystem.

  18. 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 (NCEI 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...

  19. 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

  20. Abundance and distribution of Arctic cod (Boreogadus saida) and other pelagic fishes over the U.S. Continental Shelf of the Northern Bering and Chukchi Seas

    Science.gov (United States)

    De Robertis, Alex; Taylor, Kevin; Wilson, Christopher D.; Farley, Edward V.

    2017-01-01

    We conducted acoustic-trawl (AT) surveys of the northern Bering and Chukchi Seas during ice-free periods in 2012 and 2013. The mixed species assemblages in the study area required refinement of standard AT survey methods, and adjustment of trawl catches for the effects of trawl selectivity. Sensitivity analyses indicate that the AT abundance estimates are relatively robust to the assumptions of the analysis. These surveys indicate that midwater fishes are dominated by age-0 Arctic cod (Boreogadus saida), age-0 saffron cod (Eleginus gracilis), capelin (Mallotus villosus), and Pacific herring (Clupea pallasii). In both years, age-0 Arctic cod were distributed principally ≥69.5 °N, age-0 saffron cod were abundant in coastal areas between 66.5 and 69.5 °N, and Pacific herring were distributed south of 67 °N. These three fishes exhibited consistent associations with temperature, salinity and bottom depth: e.g., age-0 Arctic cod were abundant at lower mean water column temperatures than saffron cod. In contrast, capelin were distributed throughout the study area, and were not consistently associated with environmental measures. There was a geographic trend in body length, with smaller Arctic cod, saffron cod and capelin in northern areas, but smaller herring in the south. Arctic cod, saffron cod, herring and capelin were all >2 times more abundant in 2013 than 2012. Sizeable populations of age-0 Arctic cod were observed in the northern Chukchi Sea, which suggests that this area is an important nursery ground. However, relatively few older Arctic cod were observed in this and other surveys of the area, which suggests that either overwinter mortality of age-0 Arctic cod is high, and/or these fish are not retained on the Chukchi shelf.

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

    Science.gov (United States)

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

    2013-10-01

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

  2. 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

    ... sea lions. The western DPS of Steller sea lions is listed as endangered under the Endangered Species... process is to identify potentially significant impacts to the human environment that should be analyzed in the EIS. The analysis will evaluate the impacts of the alternatives for all resources, species,...

  3. 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

  4. 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

  5. Spatial match-mismatch between juvenile fish and prey provides a mechanism for recruitment variability across contrasting climate conditions in the eastern Bering Sea.

    Directory of Open Access Journals (Sweden)

    Elizabeth Calvert Siddon

    Full Text Available Understanding mechanisms behind variability in early life survival of marine fishes through modeling efforts can improve predictive capabilities for recruitment success under changing climate conditions. Walleye pollock (Theragra chalcogramma support the largest single-species commercial fishery in the United States and represent an ecologically important component of the Bering Sea ecosystem. Variability in walleye pollock growth and survival is structured in part by climate-driven bottom-up control of zooplankton composition. We used two modeling approaches, informed by observations, to understand the roles of prey quality, prey composition, and water temperature on juvenile walleye pollock growth: (1 a bioenergetics model that included local predator and prey energy densities, and (2 an individual-based model that included a mechanistic feeding component dependent on larval development and behavior, local prey densities and size, and physical oceanographic conditions. Prey composition in late-summer shifted from predominantly smaller copepod species in the warmer 2005 season to larger species in the cooler 2010 season, reflecting differences in zooplankton composition between years. In 2010, the main prey of juvenile walleye pollock were more abundant, had greater biomass, and higher mean energy density, resulting in better growth conditions. Moreover, spatial patterns in prey composition and water temperature lead to areas of enhanced growth, or growth 'hot spots', for juvenile walleye pollock and survival may be enhanced when fish overlap with these areas. This study provides evidence that a spatial mismatch between juvenile walleye pollock and growth 'hot spots' in 2005 contributed to poor recruitment while a higher degree of overlap in 2010 resulted in improved recruitment. Our results indicate that climate-driven changes in prey quality and composition can impact growth of juvenile walleye pollock, potentially severely affecting

  6. 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.

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

    Science.gov (United States)

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

    2015-11-01

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

  8. Bering Mission Navigation Method

    OpenAIRE

    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, "Bering" sports several new technological enhancements and advanced instruments under development at the Technical University of Denmark (DTU). The autonomous on-board orbit determination method is part...

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

    Institute of Scientific and Technical Information of China (English)

    曾胤新; 陈波; 蔡明红; 何剑锋

    2001-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    邢娜; 陈敏; 黄奕普; 邱雨生

    2011-01-01

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

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

    Data.gov (United States)

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

  12. 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...

  13. 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...

  14. 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℃.

  15. 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

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

    Institute of Scientific and Technical Information of China (English)

    黄丁勇; 王建佳; 林荣澄; 田鹏; 郑新庆

    2016-01-01

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

  17. DIVERSITY AND COMMUNITY COMPOSITION OF BACTERIOPLANKTON IN THE BERING SEA DURING SUMMER 2010%2010年夏季白令海浮游细菌的多样性和群落组成分析

    Institute of Scientific and Technical Information of China (English)

    刘莹; 张芳; 凌云; 林凌; 陶妍; 何培民; 何剑锋

    2013-01-01

    海洋浮游细菌在海洋生态系统的运行中起着关键性的生物地球化学作用.利用2010年夏季第4次北极考察获得的白令海不同深度水样,运用变性梯度凝胶电泳技术以及克隆建库等方法,来了解白令海中浮游细菌的多样性和群落组成等信息.结果表明:在白令海海盆区B07站位的50 m处,其浮游细菌的香农多样性指数是最高的,为2.61;香农多样性指数最低的是B07站位的3 m处,为1.99.白令海海盆区的细菌多样性变化比陆架区要大,有可能与海洋环境的复杂变化有关.通过克隆测序,鉴定出的浮游细菌类群分为4大类:α-变形杆菌、β-变形杆菌、γ-变形杆菌和拟杆菌.其中γ-变形杆菌所占的比例最大,为53%,是白令海中的优势种群;拟杆菌其次,为37%.这些浮游细菌在白令海中的分布情况为:γ-变形杆菌和拟杆菌存在于3个位点的所有水层中,α-变形杆菌只存在于B07站位的50 m和100m水层中,β-变形杆菌除B13站位的0m处外,存在于其他站位的所有水层中.白令海B断面3个站位的温度随着深度的增加而降低,盐度随着深度的增加而升高.大体上白令海海盆区(B07站位)的硝酸盐、磷酸盐和硅酸盐浓度比陆架区(B15和B13站位)高,陆架区的铵盐浓度较海盆区高.%Marine bacterioplankton play a key biogeochemical role in the marine ecosystem.To investigate the diversity and community composition of bacterioplankton in the Bering Sea (Arctic Ocean),we collected samples from different depths during the Fourth Chinese National Arctic Research Expedition (2010 summer).Samples were analyzed using DGGE and clone libraries were constructed.In the basin area of the Bering Sea,the Shannon diversity index of bacterioplankton was highest (2.61) from B07-50 m,and lowest (1.99) from B07-3 m.There was greater variability in bacterial diversity within the basin than on the shelf of the Bering Sea,possibly related to complex changes

  18. 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...

  19. 北白令海透明胞外聚合颗粒物的含量与来源%Distribution and source of transparent exopolymer particles in the northern Bering Sea

    Institute of Scientific and Technical Information of China (English)

    马丽丽; 陈敏; 郭劳动; 林峰; 童金炉

    2012-01-01

    透明胞外聚合颗粒物(TEP)是海水中大量存在的黏性颗粒物质,它对于海洋颗粒物的聚集、有机碳的埋藏、食物网物质的传递、痕量金属的清除与迁出等均起着重要作用.本研究开展了夏季北白令海陆架、陆坡和海盆区透明胞外聚合颗粒物含量和分布的研究.结果表明,北白令海TEP含量介于34~628 mg/m3 (Xeq)之间,其中陆架、陆坡和海盆区TEP的平均含量分别为240,145和83 mg/m3 (Xeq),整体呈现由陆架向外海降低的趋势.在陆坡和海盆区,TEP含量随着深度的增加而降低,但在陆架近底层水中,观察到TEP高含量的特征,与近底层水高的TSM,POC相对应.TEP与荧光强度、TSM、POC等的关系分析显示,研究海域TEP存在两个来源,其一为海洋上层水体的浮游生物,其主要贡献于陆架上层、陆坡和海盆水体;其二为陆架沉积物的底栖生物,其通过沉积物再悬浮贡献于陆架近底层水.%Transparent exopolymer particles (TEP) are large, sticky particles in marine environments, and play a significant role in particle dynamics, carbon export, food web energy transfer and scavenging of trace metals. Samples were collected from the northern Bering Sea during summer 2010 for measurements of TEP and other hydrographic parameters to examine the abundance, distributions and sources of TEP. Our results showed that TEP concentrations ranged from 34 to 628 mg/m3(Xeq). The averaged TEP concentrations in the shelf, slope and basin were 240, 145 and 83 mg/m3(Xeq), respectively, showing a general decrease from the shelf to the basin. In the slope and basin areas, TEP concentrations decreased with the increasing depth. However, high concentrations of TEP were observed in the shelf bottom waters, coincided with the high values of TSM and POC. The correlations between TEP and fluorescence, TSM and POC suggested two sources of TEP in the northern Bering Sea: (1) in situ production from planktons in the upper

  20. Changes and influencing factors in biogenic opal export productivity in the Bering Sea over the last 4.3 Ma: Evidence from the records at IODP Site U1340

    Science.gov (United States)

    Zhang, Qiang; Chen, Muhong; Zhang, Lanlan; Su, Xiang; Xiang, Rong

    2016-08-01

    We reconstructed changes in biogenic opal export productivity (BOEP) in the southern Bering Sea (BS) over the last ˜4.3 Ma, based on mass accumulation rate (MAR) of biogenic opal from Integrated Ocean Drilling Program (IODP) Site U1340. The results show that the BOEP in the BS was high and variable between ˜4.3 and ˜1.9 Ma, extremely low and relatively stable from ˜1.9 to ˜1.1 Ma, and then fluctuated frequently (generally high during interglacials and low during glacials) during the last ˜1.1 Ma. One interval of enhanced BOEP from ˜4.3 to ˜3.2 Ma is a response to the Late Miocene-Early Pliocene "Biogenic Bloom Event." Another interval from ˜2.8 to ˜1.9 Ma correlates with global opal burial shifting from high-latitude oceans to upwelling-influenced regions following the intensification of the Northern Hemisphere Glaciation (NHG). Whereas, the increase in BS opal export productivity during the last ˜1.1 Ma tends to be a "local" phenomenon. Overall, the BOEP shows a similar trend and good correspondence to the input of the Alaskan Stream (AS), which can be traced using the Na2O/K2O ratio. We thus conclude that the AS may be the direct, and primary factor on BOEP variability in the BS during the last ˜4.3 Ma. In addition, although the poor correlation between opal MAR and volcanic glass suggests that BOEP variability was not controlled by long-term variations in the volcanism or ash abundance, increased ash abundance indicated by high contents of volcanic glasses was also a possible reason for enhanced BOEP during the period from ˜4.3 to ˜3.2 Ma and the last ˜0.5 Ma.

  1. 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.

  2. Water mass of the northward throughflow in the Bering Strait in the summer of 2003

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jinping; SHI Jiuxin; GAO Guoping; JIAO Yutian; ZHANG Hongxin

    2006-01-01

    The temperature and salinity data obtained by the Chinese national arctic research expedition (CHINARE2003) are used to study the water structure in the Bering Strait and ambient regions. Four water masses appeared in the research region: the intermediate Bering Sea water mass (IBWM), the Alaska coastal water (ACW), the Anadyr water (AW) and the Bering shelf water (BSW). The AW originates from the IBWM, but the upper layer water has been greatly altered. In the cruise on 28/29 July 2003, there were only the BSW and ACW in a section across the Bering Strait (BS section), but in the September 12/13 cruise, the AW, BSW and ACW flowed parallelly into the Bering Strait. The upper waters of these water masses were all altered due to ice melting, runoff, solar radiation, and wind mixing. The waters in the central and northern parts of Bering Strait stratified by two uniform layers,were expressed as the typical feature of the water masses originating from the pacific. A two-layer structure also dominated the vertical stratification in most part of the Chukchi Sea. An obvious subseasonal variation was observed in the BS section, which caused varying transportation of fresh water,heat, and substance, and produced a long-term and extensive impact on the Arctic Ocean.

  3. Quantifying the Bering Strait Oceanic Fluxes and their Impacts on Sea-Ice and Water Properties in the Chukchi and Beaufort Seas and Western Arctic Ocean for 2013-2014

    Science.gov (United States)

    2014-09-30

    Impacts on Sea- Ice and Water Properties in the Chukchi and Beaufort Seas and Western Arctic Ocean for 2013-2014 Rebecca Woodgate Polar Science...from the Pacific, are critical to the water properties of the Chukchi Sea, act as a trigger of sea- ice melt in the Chukchi, provide a subsurface...source of heat to the Arctic in winter (with possible impacts on sea- ice ), and are a major component of freshwater input to the Arctic (Figures 1 and 2

  4. Aerial Surveys of Endangered Whales in the Northern Bering, Eastern Chukchi, and Alaskan Beaufort Seas, 1984: with a Six Year Review, 1979-1984.

    Science.gov (United States)

    1985-06-01

    Scheidt supplied satellite imagery from the National Weather Service, U. S. Department of Commerce. Jeanne Cole and Barbara McAvoy of SEACO, Inc. typed...70048.6’ 1 0015.2’ 562 MP FE 300 0 B4 22 A-42 Il * -0- CHUIKCHI SEA 72 PT BA 71 CAPEIC CAPER ~ 1370 LEEN A-43 Flight 21: 30 July 1994 Flight was a

  5. The Bering Target Tracking Instrumentation

    DEFF Research Database (Denmark)

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

    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...

  6. 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...

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

    Data.gov (United States)

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

  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. 白令海和楚科奇海鱼类种类组成及其对生态环境变化的响应%Composition of fish species in Bering Sea and Chukchi Sea and its responses to changes of ecological environment

    Institute of Scientific and Technical Information of China (English)

    陈永俊; 林龙山; 廖运志; 张静; 宋普庆; 余兴光; 吴日升; 邵广昭

    2013-01-01

    根据第4次中国北极科学考察在白令海与楚科奇海进行的鱼类拖网调查资料,分析了白令海与楚科奇海鱼类生物的种类组成、优势种、物种多样性和区系特征,探讨了鱼类生物对北极气候快速变化的响应.结果表明,白令海与楚科奇海两个海域共鉴定鱼类生物14科41种;主要优势种类为粗壮拟庸鲽(Hippoglossoides robustus)、北鳕(Boreogadus saida)、短角床杜父鱼(Myoxocephalus scorpius)、斑鳍北鳚(Lumpenus abricii)、粗糙钩杜父鱼(Artediellus scaber);从适温性来看,冷水性种类最多,有35种,冷温性种类6种;从栖息地生态类型来看,底层鱼类、近底层鱼类和中上层鱼类分别为35、5和1种;Shannon-Wiener多样性指数平均为1.21,呈现南高北低的特点,整体多样性水平不高;气候变化引起部分北极、亚北极海区鱼类出现不同程度的纬向和纵向移动,由此将引起北极渔业资源分布格局的变化.%On the basis of trawl surveys in the Bering Sea and Chukchi Sea during the 2010 Chinese Arctic Research Expedition, the fish biodiversity feature, such as fish species composition, dominant species, biodiversity and fau-nal characteristics were conducted. We discussed the responses of fishes due to the quick changes of Arctic climate. The results show that a total of 41 species in 14 families have been recorded in Bering Sea and Chukchi Sea. The dominant species are Hippoglossoides robustus, Boreogadus saida, Myoxocephalus scorpius, Lumpenus fabricii, Artediellus scaber. There are 35 cold water species and 6 cold temperate species. The habitat types of fish can be grouped as follows: 35 demersal fishes, 5 benthopelagic fishes, and 1 pelagic fish, respectively. Shannon—Wiener diversity index(H')(range between 0 and 2. 18, and 1. 21 in average) was not high, descend from south to north. Climate change has urged some fishes to shift in their latitudinal and longitudinal distribution around the

  10. 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...

  11. Sharing seabird stories in the Bering Sea

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In March 2003, biologists from the U.S. Fish and Wildlife Service, Audubon Alaska, Kodiak Audubon, and Oregon State University spent a week in the village of...

  12. 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...

  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. The Bering Autonomous Target Detection

    DEFF Research Database (Denmark)

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

    2003-01-01

    An autonomous asteroid target detection and tracking method has been developed. The method features near omnidirectionality and focus on high speed operations and completeness of search of the near space rather than the traditional faint object search methods, employed presently at the larger...... 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...

  15. 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,...

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

    Data.gov (United States)

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

  17. 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...

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

    Institute of Scientific and Technical Information of China (English)

    CHEN Liqi; GAO Zhongyong; WANG Weiqiang; YANG Xulin

    2004-01-01

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

  19. Physical and nutrient profile data from bottle casts in the Bering Sean and the Gulf of Alaska from the R/V Alpha Helix as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) and Gulf of Alaska-1 (GAK-1) projects from 25 April 1988 to 15 May 1988 (NODC Accession 0000222)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical and nutrient profile data were collected from bottle casts in the Bering Sea and the Gulf of Alaska from the R/V Alpha Helix. Data were collected from from...

  20. 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,...

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

    Data.gov (United States)

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

  2. 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...

  3. 75 FR 81921 - Fisheries of the Exclusive Economic Zone Off Alaska; Steller Sea Lion Protection Measures for the...

    Science.gov (United States)

    2010-12-29

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

  4. 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...

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

    Data.gov (United States)

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

  6. 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...

  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 HEALY in the Arctic Ocean, Beaufort Sea and others from 2015-07-14 to 2015-10-28 (NCEI Accession 0144530)

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  10. 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 2012-08-01 to 2012-10-24 (NCEI Accession 0144338)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144338 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska and North...

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

    Data.gov (United States)

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

  12. Marine predators and persistent prey in the southeast Bering Sea

    Science.gov (United States)

    Sigler, Michael F.; Kuletz, Kathy J.; Ressler, Patrick H.; Friday, Nancy A.; Wilson, Christopher D.; Zerbini, Alexandre N.

    2012-06-01

    Predictable prey locations reduce search time and energetic costs of foraging; thus marine predators often exploit locations where prey concentrations persist. In our study, we examined whether this association is influenced by differences among predator species in foraging modes (travel cost, surface feeder or diver) or whether the predator species is a central place forager or not. We examined distributions of two seabird species during their nesting period, the surface-feeding black-legged kittiwake (Rissa tridactyla) and the pursuit-diving thick-billed murre (Uria lomvia), and two baleen whale species, the humpback whale (Megaptera novaeangliae) and the fin whale (Balaenoptera physalus), in relation to two key prey, age-1 walleye pollock (Theragra chalcogramma) and euphausiids (Euphausiidae). Prey surveys were conducted once each year during 2004 and 2006-2010. Concurrent predator surveys were conducted in 2006-2010 (seabirds) and 2008 and 2010 (whales). We compared the seabird and whale foraging locations to where age-1 pollock and euphausiids were concentrated and considered the persistence of these concentrations, where the time-scale of persistence is year (i.e., a comparison among surveys that are conducted once each year). Euphausiids were widespread and concentrations often were reliably found within specific 37 km×37 km blocks ('persistent hot spots of prey'). In contrast, age-1 pollock were more concentrated and their hot spots were persistent only on coarser scales (>37 km). Both seabird species, regardless of foraging mode, were associated with age-1 pollock but not with euphausiids, even though age-1 pollock were less persistent than euphausiids. The higher travel cost central place foragers, thick-billed murres, foraged at prey concentrations nearer their island colonies than black-legged kittiwakes, which were more widespread foragers. Humpback whales were not tied to a central place and mostly were located only where euphausiids were concentrated, and further, often in locations where these concentrations were persistent. Fin whales were associated with locations where age-1 pollock were more likely, similar to black-legged kittiwakes and thick-billed murres, but their association with euphausiids was unclear. Our results suggest that a predator's foraging mode and their restrictions during breeding affect their response to prey persistence.

  13. An integrated geospatial approach to monitoring the Bering Glacier system, Alaska

    Science.gov (United States)

    Josberger, E.G.; Payne, J.; Savage, S.; Shuchman, R.; Meadows, G.

    2004-01-01

    The Bering Glacier is the largest and longest glacier in continental North America, with an area of approximately 5,175 km2, and a length of 190 km. It is also the largest surging glacier in America, having surged at least five times during the twentieth century. The last surge of the Bering Glacier occurred in 1993-1995, since then, the glacier has undergone constant and significant retreat thereby expanding the boundaries of Vitus Lake and creating a highly dynamic system, both ecologically and hydrologically. This study utilized GIS to integrate remote sensing observations, with detailed bathymetric, hydrographic and in situ water quality measurements of the rapidly expanding Vitus Lake. Vitus Lake has nearly doubled in surface area from 58.4 km2 to 108.8 km2, with a corresponding increase in water volume from 6.1 km3 to 10.5 km3 over the same period. The remote sensing observations were used to direct a systematic bathymetric, hydrographic and water quality measurement survey in Vitus Lake which revealed a complex three dimensional structure that is the result of sea water inflow, convection generated by ice melting and the injection of fresh water from beneath the glacier.

  14. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from the NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea and Bering Sea from 2003-07-05 to 2003-08-20 (NODC Accession 0116064)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116064 includes biological, chemical, discrete sample, physical and profile data collected from NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea...

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

    Data.gov (United States)

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

  16. The inter-annual variability in the volume transport through Bering Strait and its related factors%白令海峡夏季流量的年际变化及其成因

    Institute of Scientific and Technical Information of China (English)

    张洋; 苏洁

    2012-01-01

    Bering Strait is the only channel connecting the Pacific Ocean and the Arctic Ocean. The Pacific water through the strait is mainly driven by the meridional sea level slop and its inter-annual variation has great influence on the Arctic Ocean. In this study SODA data is applied to the calculation of the monthly mean volume transport through Bering Strait. The factors related to the inter-annual variability of summer volume transport are discussed. The results show that the SSH in the Laptev Sea, the East Siberian Sea, the Chukchi Sea, south of the Beaufort Sea is negatively correlated to the volume transport of Bering Strait in inter-annual scale while the situation is opposite in the eastern shelf of Bering Sea. After analyzing the correlation of the volume flux with the Ekman transport, pumping rate, upper layer salinity, temperature and density, the paper find that the Ekman transport anomaly should be responsible for the relationship between the sea surface height and the volume flux of Bering Strait. When the SLP is positive anomaly o-ver central part of the Arctic Ocean and negative anomaly over Bering Sea basin, the volume transport through Bering Strait will be enlarged. Such SLP anomaly would explain the relationship between the Bering Strait volume transport and the Ekman transport, pumping rate and upper layer water properties to some extend. The paper reveals that the summer SLP's inter-annual variation can change SSH via Ekman transport and finally dominant the volume transport through Bering Strait.%白令海峡是连接太平洋和北冰洋的唯一通道,穿过海峡的海水体积通量在年际尺度上的变化主要取决于海峡南北两侧的海面高度差,白令海峡的入流对北冰洋海洋过程有重要的意义.利用SODA资料计算夏季白令海峡海水体积通量,对其年际变化及成因进行分析.结果表明夏季白令海峡的体积通量主要是正压地转的;当体积通量为正距平时,楚科奇海、东西

  17. An Oceanographic and Climatological Atlas of the Chukchi Sea

    Science.gov (United States)

    1990-02-01

    ZONES....................................... 303 FREEZEUP /BREAKUP DATES.................................... 304-310 5. REFERENCES...42 Average Date of Freezeup ............................ 304 I Figure 43 Median Date of Freezeup ............................. 305 Figure 44 Average...except the southern floor are common in this shear zone since these Bering Sea. FREEZEUP /BREAKUP DATES Building on the earlier work of LaBelle et al

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

    Science.gov (United States)

    Ezer, Tal; Oey, Lie-Yauw

    2013-03-01

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

  19. Vertical properties of nutrients and oxygen under temperature-salinity structure of the Bering Basin in July 1999

    Institute of Scientific and Technical Information of China (English)

    金明明

    2002-01-01

    The China R/V Xuelong went on the first Arctic scientific cruise, and we obtained 271 hydro-chemical samples from 22 deep-sea stations in the Bering Basin in late July, 1999. Here we describe vertical properties of silicate [Si], dissolved inorganic nitrogen [DIN] or [N] (nitrate plus ammonium plus nitrite), phosphate [P] and oxygen [O2] in seawater under potential temperature-salinity structure. The seasonal stratification in the summer and the water exchanges of the North Pacific Ocean over the Bering Basin resulted in that the four layers of vertical structure with two thermoclines may be found. Vertical [Si] and [N] and [P] profiles show that the nutrients are consumed mainly in ≤50 m and the order of deficient nutrients is [Si] the first, [N] the second and [P] the third. The [N] and [P] increase with depth downward to about 500 m and then both decrease, but the [Si] increases from 150 m to 2000 m or the bottom. In ≥150 m the [O2] decreases, which is related with both [P] and [N] increasing closely. Seawater [N]:[P] ratios are 6-12 in ≤50 m, 10.5-14.3 in 100-150 m and 11.7-15.8 from 300 m to the bottom.

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

    Directory of Open Access Journals (Sweden)

    M. Braun

    2012-03-01

    Full Text Available A 2008–2011 surge of Bering Glacier, Alaska is examined using observations of surface velocity and surface elevation change. Velocity measurements are obtained using synthetic aperture radar (SAR offset tracking and elevation data are obtained from the University of Alaska Fairbanks LiDAR altimetry program. Bering Glacier began to surge in May 2008 and had two phases of accelerated flow. The first phase accelerated progressively for at least 10 months and reached peak observed velocities of ~7 m d−1. Results suggest that during the quiescent phase, prior to the surge, periods of accelerated flow increased driving stresses up to 70% in a ~10 km-long section of the Lower Bering. When the first phase of the surge initiated, synchronous acceleration occurred throughout much of the glacier length, indicating widespread pressurization of the bed, but the largest accelerations initiated at the location where driving stress built up during quiescence. From there, rapid flow velocities propagated upstream and downstream across much of the glacier length and transpired as small, transient and unorganized propagation fronts. The second phase occurred in 2011 and was of comparable scale to the surge in 1993–1995, with velocities exceeding 9 m d−1 or ~18 times quiescent velocities.

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

    Data.gov (United States)

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

  2. Cretaceous to Recent extension in the Bering Strait region, Alaska

    Science.gov (United States)

    Dumitru, Trevor A.; Miller, Elizabeth L.; O'Sullivan, Paul B.; Amato, Jeffrey M.; Hannula, Kimberly A.; Calvert, Andrew T.; Gans, Phillip B.

    1995-06-01

    A key issue presented by the geology of northern Alaska concerns the demise of the Brooks Range going west toward the Bering Strait region. The main Brookian tectonic and stratigraphic elements continue into the Russian Far East, but the thick crustal root and high elevations that define the modern physiographic Brooks Range die out approaching the Bering and Chukchi shelves, which form an unusually broad area of submerged continental crust. Structural, geochronologic, and apatite fission-track data indicate that at least three episodes of extension may have affected the crust beneath the Bering Strait region, in the middle to Late Cretaceous, Eocene-early Oligocene, and Pliocene(?)-Recent. This extension may explain the present thinner crust of the region, the formation of extensive continental shelves, and the dismemberment and southward translation of tectonic elements as they are traced from the Brooks Range toward Russia. Evidence for these events is recorded within a gently tilted 10- to 15-km thick crustal section exposed on the western Seward Peninsula. The earliest episode is documented at high structural levels by the postcollision exhumation history of blueschists. Structural data indicate exhumation was accomplished in part by thinning of the crust during north-south extension bracketed between 120 and 90 Ma by 40Ar/39Ar and U-Pb ages. The Kigluaik Mountains gneiss dome rose through the crust during the later stages of this extension at 91 Ma. Similar gneiss domes occur within a broad, discontinuous belt of Cretaceous magmatism linking interior Alaska with northeast Russia; mantle-derived melts within this belt likely heated the crust and facilitated extension. Apatite fission-track ages indicate cooling below ≈120-85°C occurred sometime between 100 and 70 Ma, and the area subsequently resided at shallow crustal depths (<3-4 km) until the present. This suggests that denudation of deep levels of the crust by erosion and/or tectonism was mostly

  3. Petrology and geochronology of crustal xenoliths from the Bering Strait region: Linking deep and shallow processes in extending continental crust

    Science.gov (United States)

    Akinin, V.V.; Miller, E.L.; Wooden, J.L.

    2009-01-01

    Petrologic, geochemical, and metamorphic data on gneissic xenoliths derived from the middle and lower crust in the Neogene Bering Sea basalt province, coupled with U-Pb geochronology of their zircons using sensitive high-resolution ion microprobe-reverse geometry (SHRIMP-RG), yield a detailed comparison between the P-T-t and magmatic history of the lower crust and magmatic, metamorphic, and deformational history of the upper crust. Our results provide unique insights into the nature of lithospheric processes that accompany the extension of continental crust. The gneissic, mostly maficxenoliths (constituting less than two percent of the total xenolith population) from lavas in the Enmelen, RU, St. Lawrence, Nunivak, and Seward Peninsula fields most likely originated through magmatic fractionation processes with continued residence at granulite-facies conditions. Zircon single-grain ages (n ??? 125) are interpreted as both magmatic and metamorphic and are entirely Cretaceous to Paleocene in age (ca. 138-60 Ma). Their age distributions correspond to the main ages of magmatism in two belts of supracrustal volcanic and plutonic rocks in the Bering Sea region. Oscillatory-zoned igneous zircons, Late Cretaceous to Paleocene metamorphic zircons and overgrowths, and lack of any older inheritance in zircons from the xenoliths provide strong evidence for juvenile addition of material to the crust at this time. Surface exposures of Precambrian and Paleozoic rocks locally reached upper amphibolite-facies (sillimanite grade) to granulite-facies conditions within a series of extension-related metamorphic culminations or gneiss domes, which developed within the Cretaceous magmatic belt. Metamorphic gradients and inferred geotherms (??30-50 ??C/km) from both the gneiss domes and xenoliths aretoo high to be explained by crustal thickening alone. Magmatic heat input from the mantle is necessary to explain both the petrology of the magmas and elevated metamorphic temperatures. Deep

  4. 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.

  5. Mass balance, runoff and surges of Bering Glacier, Alaska

    Directory of Open Access Journals (Sweden)

    W. Tangborn

    2013-05-01

    Full Text Available The historical net, ablation and accumulation daily balances, as well as runoff of Bering Glacier, Alaska are determined for the 1951–2011 period with the PTAA (precipitation-temperature-area-altitude model, using daily precipitation and temperature observations collected at the Cordova and Yakutat weather stations, together with the area-altitude distribution of the glacier. The model mean annual balance for this 61 yr period is −0.6 m w.e., the accumulation balance is +1.4 and the ablation balance is −2.0 m w.e. Average annual runoff is 2.5 m w.e. Periodic surges of this glacier transport large volumes of ice to lower elevations where the ablation rate is higher, producing more negative balances and increasing runoff. Runoff from Bering Glacier (derived from simulated ablation and precipitation as rain is highly correlated with four of the glacier surges that have occurred since 1951. Ice volume loss for the 1972–2003 period measured with the PTAA model is 2.7 km3 w.e. a−1 and closely agrees with losses for the same period measured with the geodetic method. It is proposed that the timing and magnitude of daily snow accumulation and runoff, both of which are controlled by the glacier's area-altitude distribution and are calculated with the PTAA model, can be used to determine the probability that a glacier will surge.

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

    Science.gov (United States)

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

    1999-01-01

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

  7. Mass balance, runoff and surges of the Bering Glacier, Alaska

    Directory of Open Access Journals (Sweden)

    W. Tangborn

    2012-12-01

    Full Text Available The historical net, ablation and accumulation daily balances and runoff of the Bering Glacier, Alaska are determined for the 1951–2011 period with the PTAA (precipitation-temperature-area-altitude model, using daily precipitation and temperature observations collected at the Cordova and Yakutat weather stations, together with the area-altitude distribution of the glacier. The mean annual balance for this 61-yr period is −0.6 mwe, the accumulation balance is +1.4 and the ablation balance is −2.0 mwe. Periodic surges of this glacier transport large volumes of ice to lower elevations where the ablation rate is higher, producing more negative balances and increasing runoff. During the 1993–1995 surge the average ablation balance is −3.3 mwe, over a meter greater than the 1951–2011 average. Runoff from the Bering Glacier (derived from simulated ablation and precipitation as rain is highly correlated with the four glacier surges that have been observed since 1951. Ice volume loss for the 1972–2003 period measured with the PTAA model is 2.3 km3 we a−1 and closely agrees with losses for the same period measured with the geodetic method.

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

    Data.gov (United States)

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

  9. 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, Pamela A.; 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 Toxoplasma gondii, 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 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 1990s.

  10. Use of ERTS data for mapping Arctic sea ice

    Science.gov (United States)

    Barnes, J. C. (Principal Investigator); Bowley, C. J.

    1973-01-01

    The author has identified the following significant results. Data from ERTS passes crossing the Bering Sea in early March have been correlated with ice observations collected in the Bering Sea Experiment (BESEX). On two flights of the NASA CV-990 aircraft, the ice conditions in the vicinity of St. Lawrence Island reported by the onboard observer are in close agreement with the ice conditions mapped from the corresponding ERTS imagery. The ice features identified in ERTS imagery and substantiated by the aerial observer include the locations of boundaries between areas consisting of mostly grey ice and of mostly first and multi-year ice, the existence of shearing leads, and the occurrence of open water with the associated development of stratus cloud streaks. The BESEX correlative ice formation verifies the potential of practical applications of ERTS data.

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

    Science.gov (United States)

    Matthewman, N. J.; Magnusdottir, G.

    2010-12-01

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

  12. 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.

  13. 2003-2012年间白令海峡断面淡水构成的时空变化%Spatial and temporal variations of freshwater components at a transect near the Bering Strait during 2003-2012

    Institute of Scientific and Technical Information of China (English)

    潘红; 陈敏; 童金炉; 邱雨生; 郑敏芳

    2015-01-01

    Seawaterδ18 O at a transect along 64.3°N near Bering strait from 2003 to 2012 was determined,and the fractions of sea-ice melted water (SIM)and river water (RW)were calculated using mass balance of salinity andδ18 O.The spatial distribution and interannual variability of freshwater components in the Bering Strait were dis-cussed.Our results showed that the signals of depleted δ18 O,low salinity,warmer temperatures and higher river runoff fractions were found in the region affected by the Alaska Coastal Water (ACW)on the eastern part of the section,while high δ18 O,high salinity,and lower sea-ice melted water fractions were observed in the western part with the influence of Anadyr water.The moderate properties were revealed in the middle part of the section with the influence of the Bering Shelf Water.The fractions of river runoff in the region affected by the Alaska Coastal Water were approximately twice as much as in regions affected by the Bering Shelf Water and the Anadyr Water. The interannual variation of river runoff fractions in regions affected by the Alaska Coastal Water showed a charac-teristic of 2010>2012 >2003 >2008,which was regulated by the interannual variation of the Yukon River dis-charge.The fractions of sea-ice melted water were similar in the regions affected by the Bering Shelf Water and the Alaska Coastal Water,and higher (~45%)than those in the region affected by the Anadyr Water.The interannu-al variation of sea-ice melted water fractions showed a characteristic of 2003>2008≈2012>2010,controlled by the interannual variation of sea ice cover in the Bering Sea.The freshwater pass through the Bering Strait was consti-tute of 46% river water and 54% sea-ice melted water in average.The fraction ratios of river water to sea-ice mel-ted water in the regions affected by the Alaskan Coastal Water,the Bering Shelf Water,and the Anadyr Water in-creased during 2003 to 2012,indicating that the freshwater components in the Pacific inflow also play

  14. Diagnostic sea ice predictability in the pan-Arctic and U.S. Arctic regional seas

    Science.gov (United States)

    Cheng, Wei; Blanchard-Wrigglesworth, Edward; Bitz, Cecilia M.; Ladd, Carol; Stabeno, Phyllis J.

    2016-11-01

    This study assesses sea ice predictability in the pan-Arctic and U.S. Arctic regional (Bering, Chukchi, and Beaufort) seas with a purpose of understanding regional differences from the pan-Arctic perspective and how predictability might change under changing climate. Lagged correlation is derived using existing output from the Community Earth System Model Large Ensemble (CESM-LE), Pan-Arctic Ice-Ocean Modeling and Assimilation System, and NOAA Coupled Forecast System Reanalysis models. While qualitatively similar, quantitative differences exist in Arctic ice area lagged correlation in models with or without data assimilation. On regional scales, modeled ice area lagged correlations are strongly location and season dependent. A robust feature in the CESM-LE is that the pan-Arctic melt-to-freeze season ice area memory intensifies, whereas the freeze-to-melt season memory weakens as climate warms, but there are across-region variations in the sea ice predictability changes with changing climate.

  15. 75 FR 41123 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea Subarea

    Science.gov (United States)

    2010-07-15

    ... (27.4 m) lengths. By working with the nonpelagic trawl fishing industry, the AFSC determined that... trawling for the purpose of studying the effects of nonpelagic trawling on bottom habitat. The SMIHCA...

  16. The Paleoceanography of the Bering Sea During the Last Glacial Cycle

    Science.gov (United States)

    2006-02-01

    of CH 4 in marine sediments is thermogenic, where CH4 is one product of thermal degradation of Cog at depth in the sediment column where the...enough duration to perhaps be obscured by the relatively low sediment accumulation rates in the Pacific basin and poor preservation of calcite . Kiefer and...by Kim and O’Neil (1997), where calcite precipitated from solu- tions of NaHCO 3 and CaC12 in deionized water, the fractionation factor, Cf( calcite -H20

  17. 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...

  18. 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.

  19. 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...

  20. 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 environmental...

  1. 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...

  2. AFSC/ABL: Juvenile chum salmon allozyme stock identification, Bering Sea 2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Genetic stock identification techniques were used to identify the origin and provide stock-specific migration and distribution patterns of juvenile chum...

  3. Late winter population and distribution of Spectacled Eiders (Somateria fischeri) in the Bering Sea 2009

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Following satellite telemetry and aerial survey work from 1993-1998, all or most of the global population of spectacled eiders (Somateria flscheri) is believed to...

  4. 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...

  5. Variability of the Bering Sea Circulation in the Period 1992-2010

    Science.gov (United States)

    2012-06-09

    significantly larger errors (~ 10-20 cm) of geoid models (e.g., Elmann 2010). To derive the absolute SSH maps, the gridded Aviso anomalies were added to...Baltic countries. Gravity, Geoid and Earth Observation International Association of Geodesy Symposia, vol 135, part 6, pp 489-4%. doi: 10.1007/978-3

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

    Data.gov (United States)

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

  7. 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...

  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 sector...

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

    Science.gov (United States)

    Bodenstein, Barbara L.; 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).

  10. Aerial Surveys of Endangered Whales in the Beaufort, Chukchi & Northern Bering Seas.

    Science.gov (United States)

    1982-03-01

    sighted north of Cape Prince of Wales . One hundred and sixty-seven beluga , including cow-calf pairs, and 15 aringed seals including cow-pup pairs were... Wales and Cape Sabine), 4 belugas at Pt. Lay, and 3 walrus. 168 165 162 159 156 153 150 71 71 70 - 70 69 69 68 68 67 67 67 ___ 1 .KEY FOR FLIGHT 89 66...sonobuoys, that beluga whales were present. Currently we assume that problems *of sightability are smoothed over time through repetitive sampling of an

  11. 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...

  12. A baseline study of historic ice conditions in the Beaufort Sea, Chukchi Sea, and Bering Strait: Final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Final report under Outer Continental Shelf contract 03-5-022-55 or 2611262, also published with revised pagination in Environmental Assessment of the Alaskan...

  13. 20th-century glacial-marine sedimentation in Vitus Lake, Bering Glacier, Alaska, U.S.A.

    Science.gov (United States)

    Molnia, B.F.; Post, A.; Carlson, P.R.

    1996-01-01

    Vitus Lake, the ice-marginal basin at the southeastern edge of Bering Glacier, Alaska, U.S.A., is a site of modern, rapid, glacial-marine sedimentation. Rather than being a fresh-water lake, Vitus Lake is a tidally influenced, marine to brackish embayment connected to the Pacific Ocean by an inlet, the Seal River. Vitus Lake consists of five deep bedrock basins, separated by interbasinal highs. Glacial erosion has cut these basins as much as 250 m below sea level. High-resolution seismic reflection surveys conducted in 1991 and 1993 of four of Vitus Lake's basins reveal a complex, variable three-component acoustic stratigraphy. Although not fully sampled, the stratigraphy is inferred to be primarily glacial-marine units of (1) basal contorted and deformed glacial-marine and glacial sediments deposited by basal ice-contact processes and submarine mass-wasting; (2) acoustically well-stratified glacial-marine sediment, which unconformably overlies the basal unit and which grades upward into (3) acoustically transparent or nearly transparent glacial-marine sediment. Maximum thicknesses of conformable glacial-marine sediment exceed 100 m. All of the acoustically transparent and stratified deposits in Vitus Lake are modern in age, having accumulated between 1967 and 1993. The basins where these three-part sequences of "present-day" glacial-marine sediment are accumulating are themselves cut into older sequences of stratified glacial and glacial-marine deposits. These older units outcrop on the islands in Vitus Lake. In 1967, as the result of a major surge, glacier ice completely filled all five basins. Subsequent terminus retreat, which continued through August 1993, exposed these basins, providing new locations for glacial-marine sediment accumulation. A correlation of sediment thicknesses measured from seismic profiles at specific locations within the basins, with the year that each location became ice-free, shows that the sediment accumulation at some locations

  14. Pliocene palaeoceanography of the Arctic Ocean and subarctic seas.

    Science.gov (United States)

    Matthiessen, Jens; Knies, Jochen; Vogt, Christoph; Stein, Ruediger

    2009-01-13

    The Pliocene is important in the geological evolution of the high northern latitudes. It marks the transition from restricted local- to extensive regional-scale glaciations on the circum-Arctic continents between 3.6 and 2.4Ma. Since the Arctic Ocean is an almost land-locked basin, tectonic activity and sea-level fluctuations controlled the geometry of ocean gateways and continental drainage systems, and exerted a major influence on the formation of continental ice sheets, the distribution of river run-off, and the circulation and water mass characteristics in the Arctic Ocean. The effect of a water mass exchange restricted to the Bering and Fram Straits on the oceanography is unknown, but modelling experiments suggest that this must have influenced the Atlantic meridional overturning circulation. Cold conditions associated with perennial sea-ice cover might have prevailed in the central Arctic Ocean throughout the Pliocene, whereas colder periods alternated with warmer seasonally ice-free periods in the marginal areas. The most pronounced oceanographic change occurred in the Mid-Pliocene when the circulation through the Bering Strait reversed and low-salinity waters increasingly flowed from the North Pacific into the Arctic Ocean. The excess freshwater supply might have facilitated sea-ice formation and contributed to a decrease in the Atlantic overturning circulation.

  15. Distribution, Abundance, Behavior, and Bioacoustics of Endangered Whales in the Western Beaufort and Northeastern Chukchi Seas, 1979-87

    Science.gov (United States)

    1988-07-01

    the area. Other Marine Mammals a. Belukha or White Whale ( Delphinapterus leucas ) Thirty-three sightings of 140 belukhas were made in the western...contour was clipped near St . Lawrence Island in the Bering Sea. Data Processing and Quality Control A computer program (SPEED) was written to screen for...Estimates 42 c. Habitat Relationships and Behavior 43 d. Calf Sightings 44 ix Page Other Marine Mammals 44 a. Belukha, or White Whale ( Delphinapterus

  16. Arctic sea ice a major determinant in Mandt's black guillemot movement and distribution during non-breeding season.

    Science.gov (United States)

    Divoky, G J; Douglas, D C; Stenhouse, I J

    2016-09-01

    Mandt's black guillemot (Cepphus grylle mandtii) is one of the few seabirds associated in all seasons with Arctic sea ice, a habitat that is changing rapidly. Recent decreases in summer ice have reduced breeding success and colony size of this species in Arctic Alaska. Little is known about the species' movements and distribution during the nine month non-breeding period (September-May), when changes in sea ice extent and composition are also occurring and predicted to continue. To examine bird movements and the seasonal role of sea ice to non-breeding Mandt's black guillemots, we deployed and recovered (n = 45) geolocators on individuals at a breeding colony in Arctic Alaska during 2011-2015. Black guillemots moved north to the marginal ice zone (MIZ) in the Beaufort and Chukchi seas immediately after breeding, moved south to the Bering Sea during freeze-up in December, and wintered in the Bering Sea January-April. Most birds occupied the MIZ in regions averaging 30-60% sea ice concentration, with little seasonal variation. Birds regularly roosted on ice in all seasons averaging 5 h d(-1), primarily at night. By using the MIZ, with its roosting opportunities and associated prey, black guillemots can remain in the Arctic during winter when littoral waters are completely covered by ice.

  17. Evaluate the application of ERTS-A data for detecting and mapping sea ice

    Science.gov (United States)

    Barnes, J. C. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The results of the analysis of data collected during the spring and summer demonstrate that ERTS-1 imagery has a high potential for monitoring arctic sea ice conditions during the time for maximum ice extent through ice-breakup season. In the eastern Beaufort Sea area, the combination of ERTS-1 orbital overlap and a high incidence of cloud-free conditions during the spring assures a high frequency of repetitive satellite coverage. In the mid-Beaufort Sea, numerous fractures and leads can be identified, even in the early spring data. Ice features that can be identified include: development of fractures leading to the formation of distinct ice floes; growth and deterioration of leads; evidence of shearing movements of ice masses; formation of new grey ice within leads; distinction between grey, grey-white, and older forms of ice; and the deterioration of the ice surface evidenced by the formation of puddles, thaw holes, and drainage patterns. Ice conditions in the Bering Sea near St. Lawrence Island reported by aircraft observers participating in the Bering Sea Expedition are in close agreement with the ice conditions mapped from the corresponding ERTS-1 imagery. Ice features identified were: boundaries between grey ice and first year ice, shear leads, and occurrence of open water.

  18. High resolution Holocene sea ice records from Herald Canyon, Chukchi Sea

    Science.gov (United States)

    Pearce, Christof; Jakobsson, Martin; O'Regan, Matt; Rattray, Jayne; Barrientos, Natalia; Muchitiello, Francesco; Smittenburg, Rienk; Cronin, Tom; Coxall, Helen; Semiletov, Igor

    2016-04-01

    Arctic Ocean sea ice plays a critical role in the Earth's climate system because of the positive ice-albedo feedback mechanisms as well as its control on ocean-atmospheric heat exchange and potential influence on the thermohaline circulation. Key to improving our understanding of Arctic sea ice cover and its reaction to external forcing is the reconstruction of past variability through paleo-records such as marine sediment cores. Although the observed recent sea ice loss seems to be the strongest of the last millennia, it is still uncertain whether the shift from perennial to seasonal ice cover expected for the near future was unprecedented during the current interglacial. High resolution sea ice reconstructions from the Arctic Ocean are rare, and specifically records from the Russian Arctic are underrepresented. In this study, we present results from marine sediment cores from the Herald Canyon in the East Siberian Sea. The area is one of the major conduits of Pacific water entering the Arctic Ocean basin from the Bering Strait and is thus an ideal place to study past variability of the inflow of these nutrient rich waters. Radiocarbon dating of mollusks indicates very high sedimentation rates at the coring sites which allowed for analyses at centennial resolution up to decadal resolution in the late Holocene. Core samples were analyzed for the biomarker IP25, which is produced by diatoms living in sea ice and is used as a proxy of past seasonal sea ice concentrations. Preliminary results indicate the presence of seasonal sea ice during the entire Late Holocene and show a significant increase of sea ice concentrations during the last millennia.

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

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data from moorings deployed in Bering Strait from summer 2013 to summer 2014. Mooring deployments were funded by the ONR award N00014-13-1-0468...

  20. Surface depressions (Lacunas on Bering Glacier, Alaska: a product of downwasting through differential ablation

    Directory of Open Access Journals (Sweden)

    P. J. Fleisher

    2014-05-01

    Full Text Available Bering Glacier lacunas are steep-sided, flat-floored hollows ranging in size from 40 to 60 m wide, 80 to 120 m long, and 35 to 50 m in deep. They are confined within a band of clean ice (1.5 km wide, 5 km long paralleling the eastern margin of the Bering piedmont lobe. The 1993–1995 surge displaced the lacuna band several kilometers onto the foreland. Specifically significant is the formation of a new band of lacunas 5–6 years later in the same location occupied by the displaced band prior to the surge. Conditions essential to lacuna formation were initiated during the surge as overriding ice was thrust into position across the trend of a subglacial trough, leading to stagnation of ice within the trough. Stagnation combined with saturation at depth altered ice texture and density. Exposure of this ice through normal ablation led to areas of differential ablation and the formation of lacunas.

  1. Monitoring change in the Bering Glacier region, Alaska: Using Landsat TM and ERS-1 imagery

    Energy Technology Data Exchange (ETDEWEB)

    Payne, J.F. [Bureau of Land Management, Anchorage, AK (United States); Coffeen, M. [Bureau of Land Management, Glennallen, AK (United States); Macleod, R.D. [Ducks Unlimited, Inc., Sacramento, CA (United States)] [and others

    1997-06-01

    The Bering Glacier is the largest (5,180 km{sup 2}) and longest (191 km) glacier in continental North America. This glacier is one of about 200 temperate glaciers in the Alaska/Canada region that are known to surge. Surges at the Bering Glacier typically occur on a 20-30 year cycle. The objective of this project was to extract information regarding the position of the terminus of the glacier from historic aerial photography, early 20{sup th} century ground photography, Landsat Thematic Mapper (TM) satellite data, and European Space Agency, Synthetic Aperture RADAR (ERS-1 SAR) data and integrate it into a single digital database that would lend itself to change detection analysis. ERS-1 SAR data was acquired from six dates between 1992-95 and was terrain corrected and co-registered A single Landsat TM image from June 1991 was used as the base image for classifying land cover types. Historic locations of the glacier terminus were generated using traditional photo interpretation techniques from aerial and ground photography. The result of this platform combination, along with the historical data, is providing land managers with the unique opportunity to generate complete assessments of glacial movement this century and determine land cover changes which may impact wildlife and recreational opportunities.

  2. Why is Arctic sea ice melting faster than expected%北极海冰融化速度为什么超预期

    Institute of Scientific and Technical Information of China (English)

    王致平; 王立东

    2016-01-01

    Why exceeded expectations Arctic sea ice melting? Study on satellite photos to be seen, comparison, analysis, judgment, reasoning and scientific data. It was found that the Bering Sea is warm water in the North Pacific through the Bering Strait into the Arctic Ocean, causing ice to melt. Bering Sea warm pool heated mainly from the equator, the warm Kuroshio and Alaska.%北冰洋海冰融化速度为什么超预期?要找出其中的原因。把卫星照片作为研究对象,通过观察、对比、分析、判断、推理,再用科学测量数据进行验证。结果发现:是北太平洋白令海的暖水通过白令海峡,进入了北冰洋,从而造成冰盖融化。白令海的暖水主要来自太平洋的暖流,从赤道的暖池向北的黑潮到北太平洋暖流,再到阿拉斯加暖流,之后进入白令海。

  3. 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

  4. 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...

  5. 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...

  6. 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...

  7. Recent changes in Arctic sea ice melt onset, freezeup, and melt season length

    Science.gov (United States)

    Markus, Thorsten; Stroeve, Julienne C.; Miller, Jeffrey

    2009-12-01

    In order to explore changes and trends in the timing of Arctic sea ice melt onset and freezeup, and therefore melt season length, we developed a method that obtains this information directly from satellite passive microwave data, creating a consistent data set from 1979 through present. We furthermore distinguish between early melt (the first day of the year when melt is detected) and the first day of continuous melt. A similar distinction is made for the freezeup. Using this method we analyze trends in melt onset and freezeup for 10 different Arctic regions. In all regions except for the Sea of Okhotsk, which shows a very slight and statistically insignificant positive trend (0.4 d decade-1), trends in melt onset are negative, i.e., toward earlier melt. The trends range from -1.0 d decade-1 for the Bering Sea to -7.3 d decade-1 for the East Greenland Sea. Except for the Sea of Okhotsk all areas also show a trend toward later autumn freeze onset. The Chukchi/Beaufort seas and Laptev/East Siberian seas observe the strongest trends with 7 d decade-1. For the entire Arctic, the melt season length has increased by about 20 days over the last 30 years. Largest trends of over 10 d decade-1 are seen for Hudson Bay, the East Greenland Sea, the Laptev/East Siberian seas, and the Chukchi/Beaufort seas. Those trends are statistically significant at the 99% level.

  8. Decadal shifts in autumn migration timing by Pacific Arctic beluga whales are related to delayed annual sea ice formation.

    Science.gov (United States)

    Hauser, Donna D W; Laidre, Kristin L; Stafford, Kathleen M; Stern, Harry L; Suydam, Robert S; Richard, Pierre R

    2016-12-21

    Migrations are often influenced by seasonal environmental gradients that are increasingly being altered by climate change. The consequences of rapid changes in Arctic sea ice have the potential to affect migrations of a number of marine species whose timing is temporally matched to seasonal sea ice cover. This topic has not been investigated for Pacific Arctic beluga whales (Delphinapterus leucas) that follow matrilineally maintained autumn migrations in the waters around Alaska and Russia. For the sympatric Eastern Chukchi Sea ('Chukchi') and Eastern Beaufort Sea ('Beaufort') beluga populations, we examined changes in autumn migration timing as related to delayed regional sea ice freeze-up since the 1990s, using two independent data sources (satellite telemetry data and passive acoustics) for both populations. We compared dates of migration between 'early' (1993-2002) and 'late' (2004-2012) tagging periods. During the late tagging period, Chukchi belugas had significantly delayed migrations (by 2 to >4 weeks, depending on location) from the Beaufort and Chukchi seas. Spatial analyses also revealed that departure from Beaufort Sea foraging regions by Chukchi whales was postponed in the late period. Chukchi beluga autumn migration timing occurred significantly later as regional sea ice freeze-up timing became later in the Beaufort, Chukchi, and Bering seas. In contrast, Beaufort belugas did not shift migration timing between periods, nor was migration timing related to freeze-up timing, other than for southward migration at the Bering Strait. Passive acoustic data from 2008 to 2014 provided independent and supplementary support for delayed migration from the Beaufort Sea (4 day yr(-1) ) by Chukchi belugas. Here, we report the first phenological study examining beluga whale migrations within the context of their rapidly transforming Pacific Arctic ecosystem, suggesting flexible responses that may enable their persistence yet also complicate predictions of how

  9. 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.

  10. Role of the Bering Strait on the hysteresis of the ocean conveyor belt circulation and glacial climate stability.

    Science.gov (United States)

    Hu, Aixue; Meehl, Gerald A; Han, Weiqing; Timmermann, Axel; Otto-Bliesner, Bette; Liu, Zhengyu; Washington, Warren M; Large, William; Abe-Ouchi, Ayako; Kimoto, Masahide; Lambeck, Kurt; Wu, Bingyi

    2012-04-24

    Abrupt climate transitions, known as Dansgaard-Oeschger and Heinrich events, occurred frequently during the last glacial period, specifically from 80-11 thousand years before present, but were nearly absent during interglacial periods and the early stages of glacial periods, when major ice-sheets were still forming. Here we show, with a fully coupled state-of-the-art climate model, that closing the Bering Strait and preventing its throughflow between the Pacific and Arctic Oceans during the glacial period can lead to the emergence of stronger hysteresis behavior of the ocean conveyor belt circulation to create conditions that are conducive to triggering abrupt climate transitions. Hence, it is argued that even for greenhouse warming, abrupt climate transitions similar to those in the last glacial time are unlikely to occur as the Bering Strait remains open.

  11. Spatial heterogeneity in zooplankton summer distribution in the eastern Chukchi Sea in 2012-2013 as a result of large-scale interactions of water masses

    Science.gov (United States)

    Pinchuk, Alexei I.; Eisner, Lisa B.

    2017-01-01

    Interest in the Arctic shelf ecosystems has increased in recent years as the climate has rapidly warmed and sea ice declined. These changing conditions prompted the broad-scale multidisciplinary Arctic Ecosystem integrated survey (Arctic Eis) aimed at systematic, comparative analyses of interannual variability of the shelf ecosystem. In this study, we compared zooplankton composition and geographical distribution in relation to water properties on the eastern Chukchi and northern Bering Sea shelves during the summers of 2012 and 2013. In 2012, waters of Pacific origin prevailed over the study area carrying expatriate oceanic species (e.g. copepods Neocalanus spp., Eucalanus bungii) from the Bering Sea outer shelf well onto the northeastern Chukchi shelf. In contrast, in 2013, zooplankton of Pacific origin was mainly distributed over the southern Chukchi shelf, suggesting a change of advection pathways into the Arctic. These changes also manifested in the emergence of large lipid-rich Arctic zooplankton (e.g. Calanus hyperboreus) on the northeastern Chukchi shelf in 2013. The predominant copepod Calanus glacialis was composed of two distinct populations originating from the Bering Sea and from the Arctic, with the Arctic population expanding over a broader range in 2013. The observed interannual variability in zooplankton distribution on the Chukchi Sea shelf may be explained by previously described systematic oceanographic patterns derived from long-term observations. Variability in oceanic circulation and related zooplankton distributions (e.g. changes in southwestward advection of C. hyperboreus) may impact keystone predators such as Arctic Cod (Boreogadus saida) that feed on energy-rich zooplankton.

  12. 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...

  13. Foraging ecology of thick-billed murres in the Bering Sea: variability in relation to ocean thermal structure

    OpenAIRE

    國分, 亙彦; 山本, 誉士; 菊地デイル, 万次郎; 綿貫, 豊; Alexander, S. Kitaysky; 高橋, 晃周

    2013-01-01

    第4回極域科学シンポジウム横断セッション:[IA] 「急変する北極気候システム及びその全球的な影響の総合的解明」―GRENE北極気候変動研究事業研究成果報告2013―11月12日(火) 国立極地研究所 2階大会議室

  14. 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

    ... relatively volatile reproductive potential of crab stocks, the cooperative management structure of the FMP... of availability of fishery management plan amendments; request for comments. SUMMARY: The North Pacific Fishery Management Council submitted Amendments 38 and 39 to the Fishery Management Plan...

  15. 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...

  16. 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...

  17. Multi-Decadal Variability in the Bering Sea: A Synthesis of Model Results and Observations from 1948 to the Present

    Science.gov (United States)

    2013-12-01

    Co-Advisors: Wieslaw Maslowski Jaclyn Clement Kinney THIS PAGE INTENTIONALLY LEFT BLANK i REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704...Laboratory LANL Los Alamos National Laboratory MDA maritime domain awareness METOC meteorology and oceanography MIZ marginal ice zone...Arctic (USCG 2013). In order to address the United States involvement in the region, numerous guiding documents have been published and subsequently

  18. 76 FR 35781 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-06-20

    ... on their historic participation in one or more of these nine BSAI crab fisheries during a specific... geographic regions based on historic geographic delivery and processing patterns. The Western Aleutian... comment period for Amendment 37 and the proposed rule. One comment letter provided a general criticism...

  19. 78 FR 36122 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-06-17

    ....gov . The Environmental Impact Statement, RIR, and Social Impact Assessment prepared for the CR...-market or that would require the valuation of non-monetary assets. By only requiring share transfers...

  20. NPRB 1319 Assessment of the benthic impacts of raised groundgear for the Eastern Bering Sea pollock fishery.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Alaska pollock fishing industry, in collaboration with scientists at Alaska Pacific University, the Alaska Fisheries Science Center, and members of the fishing...

  1. 76 FR 49423 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-08-10

    ... accepted in Microsoft Word, Excel, WordPerfect, or Adobe portable document file (pdf) formats only. Copies... each crab fishery to aid in price negotiations and arbitrations; (2) a formula arbitrator, who prepares a non-binding price formula that describes the historic division of first whole-sale values...

  2. 77 FR 72791 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands; 2013 and...

    Science.gov (United States)

    2012-12-06

    ...). Attachments to electronic comments will be accepted in Microsoft Word or Excel, WordPerfect, or Adobe PDF file....64(a)(2) and Tables 40 and 41 to part 679 establish a formula for calculating PSC sideboard limits... fishery cooperatives in the directed pollock fishery. Section 679.64(b) establishes formulas for...

  3. 76 FR 44297 - Fisheries of the Exclusive Economic Zone Off Alaska; Allocating Bering Sea and Aleutian Islands...

    Science.gov (United States)

    2011-07-25

    ... comments will be accepted in Microsoft Word, Excel, WordPerfect, or Adobe portable document file (pdf... each crab fishery to aid in price negotiations and arbitrations; (2) a formula arbitrator, who prepares a non-binding price formula that describes the historic division of first whole-sale values...

  4. 76 FR 49417 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2011-08-10

    ... enforcement actions under joint and several liability provisions because of perceived concerns about the past... optimization of harvest rates for product recovery and quality, reduce incentives to operate in adverse...

  5. 76 FR 47493 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands King and...

    Science.gov (United States)

    2011-08-05

    ... will be implemented during the ABC-setting process as the Council's Crab Plan Team and the Scientific.... The decision to modify the definition of rebuilt from 2 consecutive annual biomass estimates at or... the confidence of the Crab Plan Team and Scientific and Statistical Committee in the stock...

  6. 76 FR 13593 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-03-14

    ... directly regulated entities would be expected to benefit from this action relative to the status quo.... ACTION: Notice of availability of a proposed amendment to a fishery management plan; request for comments. SUMMARY: The North Pacific Fishery Management Council submitted Amendment 34 to the Fishery...

  7. 76 FR 68358 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-11-04

    ..., which may be delivered to any processor and are not subject to regionalization. CPO, CPC, and CVC IFQ are not subject to regionalization and are not required to be matched with a processor holding IPQ... contract for a market report or non-binding formula for the fishery were considered and not advanced...

  8. 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...

  9. 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...

  10. 77 FR 59852 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2012-10-01

    ... language of the CRP. On May 19, 2008, the U.S. District Court for the Western District of Washington issued... found the statutory language ambiguous as to whether replacement of qualifying vessels with non... vessel would ultimately result in the elimination of the sector through vessel attrition, and...

  11. 78 FR 17341 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-03-21

    .... In some cases, a plant may switch from one production line to two lines, with large changes in the...., estimates of bait used are known to be inaccurate and unreliable). The Council recommended scaling back...

  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

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE MAGNUSON-STEVENS ACT PROVISIONS Specific Fishery or Program Fishing..., limited partnership, limited liability company, association or any other entity whatsoever, organized... contingent on such Offer being a Selected Offer at the closing of the Selection Process. Once submitted,...

  13. 78 FR 15677 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-03-12

    ... include cost, revenue, ownership, and employment data the North Pacific Fishery Management Council...: Notice of availability of fishery management plan amendment; request for comments. SUMMARY: NMFS announces that the North Pacific Fishery Management Council (Council) has submitted Amendment 42 to...

  14. 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...

  15. 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)....

  16. 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),...

  17. 78 FR 28523 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2013-05-15

    ... published a notice of availability for Amendment 41 on December 13, 2012 (77 FR 74161). The comment period... on January 30, 2013 (78 FR 6279). The comment period on the proposed rule ended on March 1, 2013... provided in the notice of availability for Amendment 41 (December 13, 2012, 77 FR 74161) and the...

  18. 76 FR 8700 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Crab...

    Science.gov (United States)

    2011-02-15

    ... on March 2, 2005 (70 FR 10174). Regulations implementing the FMP and all amendments to the Program...-designated IPQ for the WAG fishery from the West regional designation until August 17, 2010 (75 FR 7205... these shares be used in the West region. NMFS extended the emergency action on August 17, 2010 (75...

  19. 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...

  20. 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...

  1. 78 FR 42970 - Notice of Intent To Prepare a Resource Management Plan for the Bering Sea-Western Interior...

    Science.gov (United States)

    2013-07-18

    ..., and climate change. The preliminary planning criteria include: 1. Opportunities for public comment and..., Evaluation, Planning, and Management; 15. The BLM will incorporate Environmental Justice considerations in the planning alternatives to respond to Environmental Justice issues facing minority populations,...

  2. 76 FR 80782 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands; Proposed...

    Science.gov (United States)

    2011-12-27

    ... Regional Administrator, Sustainable Fisheries Division, Alaska Region, NMFS, Attn: Ellen Sebastian. You may... wish to comment on from the resulting list and click on the ``Submit a Comment'' icon on the right of..., American Fisheries Act allocations, Amendment 80 allocations, and Community Development Quota (CDQ)...

  3. 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.

  4. 76 FR 5556 - Fisheries of the Exclusive Economic Zone Off Alaska; Allocating Bering Sea and Aleutian Islands...

    Science.gov (United States)

    2011-02-01

    .../sustainablefisheries.htm . FOR FURTHER INFORMATION CONTACT: Seanbob Kelly, 907-586-7228. SUPPLEMENTARY INFORMATION: The... Program. Regulations implementing these amendments were published on March 2, 2005 (70 FR 10174), and...

  5. 77 FR 20339 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2012-04-04

    ... Kelly, 907-586-7228. SUPPLEMENTARY INFORMATION: NMFS manages the U.S. groundfish fisheries of the BSAI... Appropriations Act, 2005 (Public Law No. 108-447). Based on these criteria, NMFS determined that 28 non-AFA...

  6. 77 FR 62482 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2012-10-15

    ... anonymous). Attachments to electronic comments will be accepted in Microsoft Word or Excel, WordPerfect, or... regulations at Sec. 600.10 to include, but is not limited to, any activity that results in killing fish...

  7. 78 FR 76245 - Fisheries of the Exclusive Economic Zone Off Alaska; Greenland Turbot in the Bering Sea Subarea...

    Science.gov (United States)

    2013-12-17

    ... the most recent fisheries data in a timely fashion and would delay the closure of directed fishing for..., Acting Deputy Director, Office of Sustainable Fisheries, National Marine Fisheries Service. BILLING...

  8. 75 FR 52478 - Fisheries of the Economic Exclusive Zone Off Alaska; Pacific Cod in the Bering Sea and Aleutian...

    Science.gov (United States)

    2010-08-26

    ... comments to Sue Salveson, Assistant Regional Administrator, Sustainable Fisheries Division, Alaska Region... it would prevent NMFS from responding to the most recent fisheries data in a timely fashion and would...: 16 U.S.C. 1801 et seq. Dated: August 23, 2010. Carrie Selberg, Acting Director, Office of...

  9. 78 FR 64891 - Fisheries of the Exclusive Economic Zone Off Alaska; Atka Mackerel in the Bering Sea and Aleutian...

    Science.gov (United States)

    2013-10-30

    ... it would prevent NMFS from responding to the most recent fisheries data in a timely fashion and would..., Office of Sustainable Fisheries, National Marine Fisheries Service. BILLING CODE 3510-22-P...

  10. 78 FR 64892 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea and...

    Science.gov (United States)

    2013-10-30

    ... most recent fisheries data in a timely fashion and would delay the closure of the Pacific ocean perch...: October 25, 2013. Kelly Denit, Acting Deputy Director, Office of Sustainable Fisheries, National...

  11. 78 FR 14932 - Fisheries of the Exclusive Economic Zone Off Alaska; Reallocation of Pollock in the Bering Sea...

    Science.gov (United States)

    2013-03-08

    ... would prevent NMFS from responding to the most recent fisheries data in a timely fashion and would delay.... Dated: March 5, 2013. Kara Meckley, Acting Deputy Director, Office of Sustainable Fisheries,...

  12. 78 FR 73110 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea...

    Science.gov (United States)

    2013-12-05

    .... Mail: Submit written comments to Glenn Merrill, Assistant Regional Administrator, Sustainable Fisheries.... Fax: Address written comments to Glenn Merrill, Assistant Regional Administrator, Sustainable... from responding to the most recent fisheries data in a timely fashion and would delay the opening...

  13. 78 FR 64891 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the Bering Sea and...

    Science.gov (United States)

    2013-10-30

    ... most recent fisheries data in a timely fashion and would delay the closure of the Pacific ocean perch...: October 25, 2013. Kelly Denit, Acting Deputy Director, Office of Sustainable Fisheries, National...

  14. 78 FR 63951 - Fisheries of the Exclusive Economic Zone Off Alaska; Bering Sea and Aleutian Islands Management...

    Science.gov (United States)

    2013-10-25

    ..., Public Law 105-277, was enacted to increase U.S. citizen participation in U.S. fisheries. The AFA... species such as skates, rockfish, arrowtooth flounder, and pollock. Recent participation information for... licenses, only one is also endorsed to authorize participation in the Western GOA Pacific cod...

  15. 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...

  16. 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...

  17. 76 FR 40628 - Groundfish Fisheries of the EEZ Off Alaska; Pacific Halibut Fisheries; CDQ Program; Bering Sea...

    Science.gov (United States)

    2011-07-11

    ... fish destined for fish meal (includes offsite 42 production) DO NOT RECORD ON PTR Bones (if meal.... Meat and skin with ribs 21 removed, from sides of body behind head and in front of tail Fish meal. Meal from whole fish or fish parts; includes 32 bone meal Fish oil. Rendered oil from whole fish or...

  18. Operational Data Report C&GS DR-8, Seismic Reflection Profiles Northern Bering Sea (NODC Accession 7000753)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A series of seismic reflection profiles were taken aboard the USC&GSS SURVEYOR during the summer of 1969 as part of a general continental shelf survey in the...

  19. Hydrography and circulation of ice-marginal lakes at Bering Glacier, Alaska, U.S.A.

    Science.gov (United States)

    Josberger, E.G.; Shuchman, R.A.; Meadows, G.A.; Savage, S.; Payne, J.

    2006-01-01

    An extensive suite of physical oceanographic, remotely sensed, and water quality measurements, collected from 2001 through 2004 in two ice-marginal lakes at Bering Glacier, Alaska-Berg Lake and Vitus Lake-show that each has a unique circulation controlled by their specific physical forcing within the glacial system. Conductivity profiles from Berg Lake, perched 135 m a.s.l., show no salt in the lake, but the temperature profiles indicate an apparently unstable situation, the 4??C density maximum is located at 10 m depth, not at the bottom of the lake (90 m depth). Subglacial discharge from the Steller Glacier into the bottom of the lake must inject a suspended sediment load sufficient to marginally stabilize the water column throughout the lake. In Vitus Lake, terminus positions derived from satellite imagery show that the glacier terminus rapidly retreated from 1995 to the present resulting in a substantial expansion of the volume of Vitus Lake. Conductivity and temperature profiles from the tidally influenced Vitus Lake show a complex four-layer system with diluted (???50%) seawater in the bottom of the lake. This lake has a complex vertical structure that is the result of convection generated by ice melting in salt water, stratification within the lake, and freshwater entering the lake from beneath the glacier and surface runoff. Four consecutive years, from 2001 to 2004, of these observations in Vitus Lake show little change in the deep temperature and salinity conditions, indicating limited deep water renewal. The combination of the lake level measurements with discharge measurements, through a tidal cycle, by an acoustic Doppler Current Profiler (ADCP) deployed in the Seal River, which drains the entire Bering system, showed a strong tidal influence but no seawater entry into Vitus Lake. The ADCP measurements combined with lake level measurements established a relationship between lake level and discharge, which when integrated over a tidal cycle, gives a

  20. A Pliocene flora and insect fauna from the Bering Strait region

    Science.gov (United States)

    Hopkins, D.M.; Matthews, J.V.; Wolfe, J.A.; Silberman, M.L.

    1971-01-01

    A flood-plain forest has been preserved beneath a lava flow that invaded the Inmachuk River Valley in the northern part of the Seward Peninsula, Alaska, during the Pliocene Epoch. The fossil flora is of great biogeographic interest because of its position (Fig. 1) in a tundra region about 250 km east of Bering Strait, 75 km south of the Arctic Circle, and 65 km west of the northwestern limit of spruce-birch forest. It provides insight into the history of the development of the circumpolar boreal forest (taiga). A rich arthropod fauna casts light on the phylogeny of several modern insect genera and on the origin of modern tundra faunas. A potassium-argon analysis of the overlying basaltic lava provides our first radiometric age estimate (5.7??0.2 million years) for the Clamgulchian Stage, a Late Tertiary time-stratigraphic unit based on fossil plants and widely recognized in Alaska (Wolfe and Hopkins 1967) and northeastern Siberia. ?? 1971.

  1. Arctic Sea Ice Variability and Trends, 1979-2006

    Science.gov (United States)

    Parkinson, Claire L.; Cavalieri, Donald J.

    2008-01-01

    Analysis of Arctic sea ice extents derived from satellite passive-microwave data for the 28 years, 1979-2006 yields an overall negative trend of -45,100 +/- 4,600 km2/yr (-3.7 +/- 0.4%/decade) in the yearly averages, with negative ice-extent trends also occurring for each of the four seasons and each of the 12 months. For the yearly averages the largest decreases occur in the Kara and Barents Seas and the Arctic Ocean, with linear least squares slopes of -10,600 +/- 2,800 km2/yr (-7.4 +/- 2.0%/decade) and -10,100 +/- 2,200 km2/yr (-1.5 +/- 0.3%/decade), respectively, followed by Baffin Bay/Labrador Sea, with a slope of -8,000 +/- 2,000 km2/yr) -9.0 +/- 2.3%/decade), the Greenland Sea, with a slope of -7,000 +/- 1,400 km2/yr (-9.3 +/- 1.9%/decade), and Hudson Bay, with a slope of -4,500 +/- 900 km2/yr (-5.3 +/- 1.1%/decade). These are all statistically significant decreases at a 99% confidence level. The Seas of Okhotsk and Japan also have a statistically significant ice decrease, although at a 95% confidence level, and the three remaining regions, the Bering Sea, Canadian Archipelago, and Gulf of St. Lawrence, have negative slopes that are not statistically significant. The 28-year trends in ice areas for the Northern Hemisphere total are also statistically significant and negative in each season, each month, and for the yearly averages.

  2. Arctic marine mammal population status, sea ice habitat loss, and conservation recommendations for the 21st century.

    Science.gov (United States)

    Laidre, Kristin L; Stern, Harry; Kovacs, Kit M; Lowry, Lloyd; Moore, Sue E; Regehr, Eric V; Ferguson, Steven H; Wiig, Øystein; Boveng, Peter; Angliss, Robyn P; Born, Erik W; Litovka, Dennis; Quakenbush, Lori; Lydersen, Christian; Vongraven, Dag; Ugarte, Fernando

    2015-06-01

    Arctic marine mammals (AMMs) are icons of climate change, largely because of their close association with sea ice. However, neither a circumpolar assessment of AMM status nor a standardized metric of sea ice habitat change is available. We summarized available data on abundance and trend for each AMM species and recognized subpopulation. We also examined species diversity, the extent of human use, and temporal trends in sea ice habitat for 12 regions of the Arctic by calculating the dates of spring sea ice retreat and fall sea ice advance from satellite data (1979-2013). Estimates of AMM abundance varied greatly in quality, and few studies were long enough for trend analysis. Of the AMM subpopulations, 78% (61 of 78) are legally harvested for subsistence purposes. Changes in sea ice phenology have been profound. In all regions except the Bering Sea, the duration of the summer (i.e., reduced ice) period increased by 5-10 weeks and by >20 weeks in the Barents Sea between 1979 and 2013. In light of generally poor data, the importance of human use, and forecasted environmental changes in the 21st century, we recommend the following for effective AMM conservation: maintain and improve comanagement by local, federal, and international partners; recognize spatial and temporal variability in AMM subpopulation response to climate change; implement monitoring programs with clear goals; mitigate cumulative impacts of increased human activity; and recognize the limits of current protected species legislation.

  3. Tsivat Basin conduit system persists through two surges, Bering Piedmont Glacier, Alaska

    Science.gov (United States)

    Fleisher, P.J.; Cadwell, D.H.; Muller, E.H.

    1998-01-01

    The 1993-1995 surge of Bering Glacier, Alaska, occurred in two distinct phases. Phase 1 of the surge began on the eastern sector in July, 1993 and ended in July, 1994 after a powerful outburst of subglacial meltwater into Tsivat Lake basin on the north side of Weeping Peat Island. Within days, jokulhlaup discharge built a 1.5 km2 delta of ice blocks (25-30 m) buried in outwash. By late October 1994, discharge temporarily shifted to a vent on Weeping Peat Island, where a second smaller outburst dissected the island and built two new sandar. During phase 2, which began in spring 1995 and ended within five months, continuous discharge issued from several vents along the ice front on Weeping Peat Island before returining to the Tsivat Basin. Surge related changes include a five- to six-fold increase in meltwater turbidity; the redirection of supercooled water in two ice-contact lakes; and an increase in the rate of glaciolacustrine sedimentation. US Geological Survey aerial photos by Austin Post show large ice blocks in braided channels indicating excessive subglacial discharge in a similar position adjacent to Weeping Peat Island during the 1966-1967 surge. During the subsequent three decades of retreat, the location of ice-marginal, subglacial discharge vents remained aligned on a linear trend that describes the position of a persistent subglacial conduit system. The presence of a major conduit system, possibly stabilized by subglacial bedrock topography, is suggested by: 1) high-level subglacial meltwater venting along the northern side of Weeping Peat Island during the 1966-1967 surge, 2) persistent low-level discharge between surges, and 3) the recurrence of localizing meltwater outbursts associated with both phases of the 1993-1005 surge.

  4. 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.

  5. 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

  6. 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

  7. Numerical experiments of dynamical processes during the 2011-2013 surge of the Bering-Bagley Glacier System, using a full-Stokes finite element model

    Science.gov (United States)

    Trantow, Thomas

    The Bering-Bagley Glacial System (BBGS) is the largest glacier system outside of the Greenland and Antarctic ice sheets, and is the Earth's largest surge-type glacier. Surging is one of three types of glacial acceleration and the least understood one. Understanding glacial acceleration is paramount when trying to explain ice discharge to the oceans and the glacial contribution to sea-level rise, yet there are currently no numerical glacial models that account for surging. The recent 2011-2013 surge of the BBGS provides a rare opportunity to study the surge process through observations and the subsequent data analysis and numerical modeling. Using radar, altimeter, and image data collected from airborne and satellite missions, various descriptions of ice geometry are created at different times throughout the surge. Using geostatistical estimation techniques including variography and ordinary kriging, surface and bedrock Digital Elevation Maps (DEMs) are derived. A time series analysis of elevation change during the current surge is then conducted and validated using a complete error analysis along with airborne observations. The derived DEMs are then used as inputs to a computer simulated model of glacier dynamics in the BBGS. Using the Finite Element software Elmer/Ice, a full-Stokes simulation, with Glen's flow law for temperate ice, is created for numerical experiments. With consideration of free surface evolution, glacial hydrology and surface mass balance, the model is able to predict a variety of field variables including velocity, stress, strain-rate, pressure and surface elevation change at any point forward in time. These outputs are compared and validated using observational data such as CryoSat-2 altimetry, airborne field data, imagery and previous detailed analysis of the BBGS. Preliminary results reveal that certain surge phenomena such as surface elevation changes, surge progression and locations at which the surge starts, can be recreated using the

  8. Recent Changes in Arctic Sea Ice Melt Onset, Freeze-Up, and Melt Season Length

    Science.gov (United States)

    Markus, Thorsten; Stroeve, Julienne C.; Miller, Jeffrey

    2010-01-01

    In order to explore changes and trends in the timing of Arctic sea ice melt onset and freeze-up and therefore melt season length, we developed a method that obtains this information directly from satellite passive microwave data, creating a consistent data set from 1979 through present. We furthermore distinguish between early melt (the first day of the year when melt is detected) and the first day of continuous melt. A similar distinction is made for the freeze-up. Using this method we analyze trends in melt onset and freeze-up for 10 different Arctic regions. In all regions except for the Sea of Okhotsk, which shows a very slight and statistically insignificant positive trend (O.4 days/decade), trends in melt onset are negative, i.e. towards earlier melt. The trends range from -1.0day/decade for the Bering Sea to -7.3 days/decade for the East Greenland Sea. Except for the Sea of Okhotsk all areas also show a trend towards later autumn freeze onset. The Chukchi/Beaufort Seas and Laptev/East Siberian Seas observe the strongest trends with 7 days/decade. For the entire Arctic, the melt season length has increased by about 20 days over the last 30 years. Largest trends of over 1O days/decade are seen for Hudson Bay, the East Greenland Sea the Laptev/East Siberian Seas, and the Chukchi/Beaufort Seas. Those trends are statistically significant a1 the 99% level.

  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, 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 be...

  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. Oceanographic station data from bottle casts from the BERING STRAIT from Ocean Weather Station V (OWS-V) in the North Pacific Ocean 17 November 1968 to 05 December 1968 (NODC Accession 6900563)

    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 collected...

  13. Oceanographic station data from bottle casts from the BERING STRAIT from Ocean Weather Station V (OWS-V) in the North Pacific Ocean 05 July 1969 to 25 July 1969 (NODC Accession 6900858)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic station data were collected from the BERING STRAIT within a 1-mile radius of Ocean Weather Station V (3400N 16400E) and in transit. Data were...

  14. 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...

  15. Temperature profiles from MBT casts from the BERING STRAIT from Ocean Weather Station V (OWS-V) in the North Pacific Ocean from 19 October 1961 to 12 November 1961 (NODC Accession 6100264)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathythermograph data were collected from the BERING STRAIT within a 1-mile radius of Ocean Weather Station V (3400N 16400E) and in transit. Data were collected by...

  16. 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...

  17. 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...

  18. Oceanographic station data from bottle and CTD casts from the BERING STRAIT and other platforms from multiple Ocean Weather Station (OWS) in the North Atlantic Ocean and North Pacific Ocean 21 January 1969 to 10 April 1969 (NODC Accession 6900639)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic station data were collected from the BERING STRAIT, DUANE, CHASE, and GRESHAM within a 1-mile radius of Ocean Weather Station B (5630N 05100W), C...

  19. The Timing of Arctic Sea Ice Advance and Retreat as an Indicator of Ice-Dependent Marine Mammal Habitat

    Science.gov (United States)

    Stern, H. L.; Laidre, K. L.

    2013-12-01

    The Arctic is widely recognized as the front line of climate change. Arctic air temperature is rising at twice the global average rate, and the sea-ice cover is shrinking and thinning, with total disappearance of summer sea ice projected to occur in a matter of decades. Arctic marine mammals such as polar bears, seals, walruses, belugas, narwhals, and bowhead whales depend on the sea-ice cover as an integral part of their existence. While the downward trend in sea-ice extent in a given month is an often-used metric for quantifying physical changes in the ice cover, it is not the most relevant measure for characterizing changes in the sea-ice habitat of marine mammals. Species that depend on sea ice are behaviorally tied to the annual retreat of sea ice in the spring and advance in the fall. Changes in the timing of the spring retreat and the fall advance are more relevant to Arctic marine species than changes in the areal sea-ice coverage in a particular month of the year. Many ecologically important regions of the Arctic are essentially ice-covered in winter and ice-free in summer, and will probably remain so for a long time into the future. But the dates of sea-ice retreat in spring and advance in fall are key indicators of climate change for ice-dependent marine mammals. We use daily sea-ice concentration data derived from satellite passive microwave sensors to calculate the dates of sea-ice retreat in spring and advance in fall in 12 regions of the Arctic for each year from 1979 through 2013. The regions include the peripheral seas around the Arctic Ocean (Beaufort, Chukchi, East Siberian, Laptev, Kara, Barents), the Canadian Arctic Archipelago, and the marginal seas (Okhotsk, Bering, East Greenland, Baffin Bay, Hudson Bay). We find that in 11 of the 12 regions (all except the Bering Sea), sea ice is retreating earlier in spring and advancing later in fall. Rates of spring retreat range from -5 to -8 days/decade, and rates of fall advance range from +5 to +9

  20. Spatially Mapped Reductions in the Length of the Arctic Sea Ice Season

    Science.gov (United States)

    Parkinson, Claire L.

    2014-01-01

    Satellite data are used to determine the number of days having sea ice coverage in each year 1979-2013 and to map the trends in these ice-season lengths. Over the majority of the Arctic seasonal sea ice zone, the ice season shortened at an average rate of at least 5 days/decade between 1979 and 2013, and in a small area in the northeastern Barents Sea the rate of shortening reached over 65 days/decade. The only substantial non-coastal area with lengthening sea ice seasons is the Bering Sea, where the ice season lengthened by 5-15 days/decade. Over the Arctic as a whole, the area with ice seasons shortened by at least 5 days/decade is 12.4 × 10(exp 6) square kilimeters, while the area with ice seasons lengthened by at least 5 days/decade is only 1.1 × 10(exp 6) square kilometers. The contrast is even greater, percentage-wise, for higher rates.

  1. 75 FR 44927 - Fisheries of the Exclusive Economic Zone Off Alaska; Pollock for American Fisheries Act Catcher...

    Science.gov (United States)

    2010-07-30

    ... participating in the inshore open access fishery in the Bering Sea subarea of the Bering Sea and Aleutian... CFR part 679. The 2010 Bering Sea pollock TAC allocated to the AFA inshore open access fishery in the... inshore open access fishery in the Bering Sea subarea. After the effective date of this closure...

  2. 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.

  3. Marine mammal acoustic detections in the northeastern Chukchi Sea, September 2007-July 2011

    Science.gov (United States)

    Hannay, David E.; Delarue, Julien; Mouy, Xavier; Martin, Bruce S.; Leary, Del; Oswald, Julie N.; Vallarta, Jonathan

    2013-09-01

    Several cetacean and pinniped species use the northeastern Chukchi Sea as seasonal or year-round habitat. This area has experienced pronounced reduction in the extent of summer sea ice over the last decade, as well as increased anthropogenic activity, particularly in the form of oil and gas exploration. The effects of these changes on marine mammal species are presently unknown. Autonomous passive acoustic recorders were deployed over a wide area of the northeastern Chukchi Sea off the coast of Alaska from Cape Lisburne to Barrow, at distances from 8 km to 200 km from shore: up to 44 each summer and up to 8 each winter. Acoustic data were acquired at 16 kHz continuously during summer and on a duty cycle of 40 or 48 min within each 4-h period during winter. Recordings were analyzed manually and using automated detection and classification systems to identify calls. Bowhead (Balaena mysticetus) and beluga (Delphinapterus leucas) whale calls were detected primarily from April through June and from September to December during their migrations between the Bering and Beaufort seas. Summer detections were rare and usually concentrated off Wainwright and Barrow, Alaska. Gray (Eschrichtius robustus) whale calls were detected between July and October, their occurrence decreasing with increasing distance from shore. Fin (Balaenoptera physalus), killer (Orcinus orca), minke (Balaenoptera acutorostrata), and humpback (Megaptera novaeangliae) whales were detected sporadically in summer and early fall. Walrus (Odobenus rosmarus) was the most commonly detected species between June and October, primarily occupying the southern edge of Hanna Shoal and haul-outs near coastal recording stations off Wainwright and Point Lay. Ringed (Pusa hispida) and bearded (Erignathus barbatus) seals occur year-round in the Chukchi Sea. Ringed seal acoustic detections occurred throughout the year but detection numbers were low, likely due to low vocalization rates. Bearded seal acoustic detections

  4. 白令海峡水团来源的镭同位素示踪%Water masses in the Bering Strait revealed by radium isotopes

    Institute of Scientific and Technical Information of China (English)

    陈敏; 李艳平; 邱雨生; 杨俊鸿

    2011-01-01

    Radium isotopes in the water column along 64.3°N in the Bering Strait were determined to reveal the northward flow of the Pacific water.The specific activities of 226 Ra and 228Ra, and the 228 Ra/226 Ra)A.R.show a longitudinal variation in the Bering Strait, depicting the pathways of Pacific inflow.Based on the distributions of temperature, salinity and radium isotopes in the Bering Strait, three water masses were identified: the Anadyr Water in the western channel, the Alaskan Coastal Water in the eastern channel, and the Bering Shelf Water in the central strait.A subseasonal variation of radium isotopes in the Bering Strait was observed.The specific activities of 226 Ra and 228 Ra, and 228 Ra/226 Ra) A.R in September are higher than those observed in July, indicating water in the western Bering Strait is influenced by the southward flow of the Siberia Coastal Current in September.%对白令海峡64.3°N纬向断面镭同位素的研究表明,水体中226Ra比活度、228Ra比活度和228Ra/226Ra)A.R.存在明显的纬向变化,反映出太平洋与北冰洋水体交换的多种路径.根据温度、盐度和镭同位素的水平与垂直分布,太平洋水进入北冰洋的路径可能主要有3支,分别为白令海峡西侧的阿拉德水、白令海峡东侧的阿拉斯加沿岸水和中部的白令海陆架水.2003年7月和9月对该断面西侧站位进行的复测显示,水体中的226Ra比活度、228Ra比活度和228Ra/226Ra)A.R.发生了明显变化,9月份测值均高于7月份测值,说明白令海峡西部水体在9月份可能受到西伯利亚沿岸流南向混合的影响.

  5. ICE-RAFTED D ETRITUS EVENTS AND PALEOCEANOGRAPHIC RECORDS IN THE BERING BASIN SINCE THE LAST D EGLACIATION%末次冰消期以来白令海盆的冰筏碎屑事件与古海洋学演变记录

    Institute of Scientific and Technical Information of China (English)

    陈志华; 陈毅; 王汝建; 黄元辉; 刘欣德; 王磊; 邹建军

    2014-01-01

    通过对白令海盆中部BR02岩芯高分辨率的颜色、粒度和元素地球化学地层的研究发现:(1)该岩芯较为完整地记录了末次盛冰期结束以来(约16.3 ka BP)的多期冰筏碎屑事件,包括H1、OD、YD和北方2期,其中以H1和YD最为显著,反映了末次冰消期以来该地区海冰/冰山以及区域性冰川的消长变化;(2)BR02岩芯上部17-25 cm段出现富Mn、富Ba的氧化型沉积,说明在全新世高海面时期,白令海与北太平洋、北冰洋之间的水体交换达到极点,白令海环流加强,海盆底层水含氧状况明显改善,并引发海洋生产力增加;(3)CaO、Na2 O、Sr、Zr及Na2 O/K2 O比值的分布说明,海盆冰筏碎屑主要来自富碳酸盐的育空河流域,其次为阿拉斯加半岛和阿留申群岛等火山岩区;岩芯上部Na2 O/K2 O比值的递增暗示10 ka BP以来与火山物质输运有关的北太平洋入流(阿拉斯加流)可能增加。%From a high-resolution study of sediment grain size,color reflectance and elemental stratigraphy of core BR02, which was dredged from the central part of the Bering Basin,we came to the following conclusions.(1 )Core BR02 provides perfect records of the ice-rafted detritus (IRD)events that have happened since 16.3 ka BP at the end of the Last Glacial Maximum,including the H1 ,OD,YD and Boreal 2 events,of which H1 and YD are the most sig-nificant.These IRD events all happened during cold episodes or stadials,and indicate changes in sea ice/icebergs in the sea and local glaciers in the surrounding lands.(2)The interval of Mn-and Ba-rich sediments at 17-25 cm in the upper part of BR02 indicates that water exchange between the North Pacific Ocean,the Bering Sea,and the Arctic Ocean increased to its highest level during the Holocene high-sea-level period,which induced changes in the circulation and seabed redox and an increase in marine productivity in the Bering Basin.(3)The

  6. Sea ice cover variability and river run-off in the western Laptev Sea (Arctic Ocean) since the last 18 ka

    Science.gov (United States)

    Hörner, T.; Stein, R.; Fahl, K.; Birgel, D.

    2015-12-01

    Multi-proxy biomarker measurements were performed on two sediment cores (PS51/154, PS51/159) with the objective reconstructing sea ice cover (IP25, brassicasterol, dinosterol) and river-runoff (campesterol, β-sitosterol) in the western Laptev Sea over the last 18 ka with unprecedented temporal resolution. The sea ice cover varies distinctly during the whole time period. The absence of IP25 during 18 and 16 ka indicate that the western Laptev Sea was mostly covered with permanent sea ice (pack ice). However, a period of temporary break-up of the permanent ice coverage occurred at c. 17.2 ka (presence of IP25). Very little river-runoff occurred during this interval. Decreasing terrigenous (riverine) input and synchronous increase of marine produced organic matter around 16 ka until 7.5 ka indicate the gradual establishment of a marine environment in the western Laptev Sea related to the onset of the post-glacial transgression of the shelf. Strong river run-off and reduced sea ice cover characterized the time interval between 15.2 and 12.9 ka, including the Bølling/Allerød warm period (14.7 - 12.9 ka). Moreover, the DIP25 Index (ratio of HBI-dienes and IP25) might document the presence of Atlantic derived water at the western Laptev Sea shelf area. A sudden return to severe sea ice conditions occurred during the Younger Dryas (12.9 - 11.6 ka). This abrupt climate change was observed in the whole circum-Arctic realm (Chukchi Sea, Bering Sea, Fram Strait and Laptev Sea). At the onset of the Younger Dryas, a distinct alteration of the ecosystem (deep drop in terrigenous and phytoplankton biomarkers) may document the entry of a giant freshwater plume, possibly relating to the Lake Agassiz outburst at 13 ka. IP25 concentrations increase and higher values of the PIP25 Index during the last 7 ka reflect a cooling of the Laptev Sea spring season. Moreover, a short-term variability of c. 1.5 thousand years occurred during the last 12 ka, most probably following Bond Cycles.

  7. Changes in size and trends of North American sea duck populations associated with North Pacific oceanic regime shifts

    Science.gov (United States)

    Flint, Paul L.

    2013-01-01

    Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts.

  8. A Microwave Technique for Mapping Ice Temperature in the Arctic Seasonal Sea Ice Zone

    Science.gov (United States)

    St.Germain, Karen M.; Cavalieri, Donald J.

    1997-01-01

    A technique for deriving ice temperature in the Arctic seasonal sea ice zone from passive microwave radiances has been developed. The algorithm operates on brightness temperatures derived from the Special Sensor Microwave/Imager (SSM/I) and uses ice concentration and type from a previously developed thin ice algorithm to estimate the surface emissivity. Comparisons of the microwave derived temperatures with estimates derived from infrared imagery of the Bering Strait yield a correlation coefficient of 0.93 and an RMS difference of 2.1 K when coastal and cloud contaminated pixels are removed. SSM/I temperatures were also compared with a time series of air temperature observations from Gambell on St. Lawrence Island and from Point Barrow, AK weather stations. These comparisons indicate that the relationship between the air temperature and the ice temperature depends on ice type.

  9. Arctic sea ice melt onset from passive microwave satellite data: 1979–2012

    Directory of Open Access Journals (Sweden)

    A. C. Bliss

    2014-06-01

    Full Text Available An updated version of the Snow Melt Onset Over Arctic Sea Ice from SMMR and SSM/I-SSMIS Brightness Temperatures is now available. The data record has been re-processed and extended to cover the years 1979–2012. From this data set, a statistical summary of melt onset (MO dates on Arctic sea ice is presented. The mean MO date for the Arctic Region is 13 May (132.5 DOY with a standard deviation of ±7.3 days. Regionally, mean MO dates vary from 15 March (73.2 DOY in the St. Lawrence Gulf to 10 June (160.9 DOY in the Central Arctic. Statistically significant decadal trends indicate that MO is occurring 6.6 days decade−1 earlier in the year for the Arctic Region. Regionally, MO trends are as great as −11.8 days decade−1 in the East Siberian Sea. The Bering Sea is an outlier and MO is occurring 3.1 days decade−1 later in the year.

  10. Mammals of the Sea.

    Science.gov (United States)

    Naturescope, 1986

    1986-01-01

    Presents information on sea mammals, including definitions and characteristics of cetaceans, pinnipeds, and sirenians. Contains descriptions of the teaching activities "Whale Music,""Draw A Whale to Scale,""Adopt a Sea Mammal," and "Sea Mammal Sleuths." (TW)

  11. The role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jinlun; MI ke Steele; Rebecca Woodgate

    2008-01-01

    A model study is conducted to examine the role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007. The model generally agrees with the observations in showing considerable seasonal and intcrannual variability of the Pacific water inflow at Bering Strait in response to changes in atmospheric circulation.During summer 2007 anomalously strong southerly winds over the Pacific sector of the Arctic Ocean strengthen the ocean circulation and bring more Pacific water into the Arctic than the recent (2000-2006) average. The simulated summer (3 months )2007 mean Pacific water inflow at Bering Strait is 1.2 Sv, which is the highest in the past three decades of the simulation and is 20% higher than the recent average. Particularly, the Pacific water inflow in September 2007 is about 0.5 Sv or 50% above the 2000-2006 average. The strengthened warm Pacific water inflow carries an additional 1.0 × 1020 Joules of heat into the Arctic, enough to melt an additional 0. 5 m of ice over the whole Chukchi Sea. In the model the extra summer oceanic heat brought in by the Pacific water mainly stays in the Chukchi and Beaufort region, contributing to the wanning of surface waters in that region. The heat is in constant contact with the ice cover in the region in July through September. Thus the Pacific water plays a role in ice melting in the Chukchi and Beaufort region all summer long in 2007, likely contributing to up to 0.5 m per month additional ice melting in some area of that region.

  12. Alaska Phocid Argos Telemetry Archive (2004-2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Polar Ecosystems Program conducts research and monitoring on phocid seals in the East Bering Sea, West Bering Sea, Gulf of Alaska, Beaufort Sea, and Chukchi Sea...

  13. Winter climate change and sea ice-atmosphere interaction at high northern latitudes in ERA40 dataset

    Institute of Scientific and Technical Information of China (English)

    Liu Xiying

    2006-01-01

    Based on the reanalysis dataset ERA40 of European Center of Medium Range Weather Forcast (ECMWF), winter climate change and characteristics of sea ice-atmosphere interaction at high northern latitudes for recent several tens of years are analyzed. Superposed upon the background of global warming, the amplitude of temperature increase in winter at high northern latitudes is bigger and it exhibits different features in different regions. From the end of 1970 s, the Greenland Sea, the Barents Sea and most part of Euro-Asian continent and North American continent are getting warmer, whereas the Labrador Sea, the Greenland and the area around the Bering Strait are getting colder. Meanwhile, the sea level pressure in the central part of the northern polar region and the place where the climatic Icelandic low exist decreases, but in places farther southward it increases. Since the 1970 s, the sensible heat flux and latent heat flux sent to the atmosphere from the Greenland Sea and the Barents Sea has increased, this is mainly due to the reduction of sea ice concentration and the weakening of insulator and shield effect of the solid ice accordingly caused by the increase of air temperature. In sea ice free area of the Norwegian Sea, the sensible heat flux and latent heat flux sent to the atmosphere has reduced due to decrease of temperature and humidity differences between the air and the sea surface caused by increase of air temperature and humidity. In the Labrador Sea, due to decrease of air temperature and humidity and increase of temperature and humidity differences between the air and the sea surface accordingly, the sea gives more sensible heat flux and latent heat flux to the air. This will lead to the growth of sea ice extent there. The features of linear regression of sea level pressure, sea ice concentration and sum of sensible heat flux and latent heat flux toward time series of the leading mode of EOF expansion of surface air temperature are close to those of

  14. Estimating Arctic sea-ice freeze-up and break-up from the satellite record: A comparison of different approaches in the Chukchi and Beaufort Seas

    Directory of Open Access Journals (Sweden)

    Mark Johnson

    2016-09-01

    Full Text Available 1. Abstract The recognized importance of the annual cycle of sea ice in the Arctic to heat budgets, human behavior, and ecosystem functions, requires consistent definitions of such key events in the ice cycle as break-up and freeze-up. An internally consistent and reproducible approach to characterize the timing of these events in the annual sea-ice cycle is described. An algorithm was developed to calculate the start and end dates of freeze-up and break-up and applied to time series of satellite-derived sea-ice concentration from 1979 to 2013. Our approach builds from discussions with sea-ice experts having experience observing and working on the sea ice in the Bering, Chukchi and Beaufort Seas. Applying the algorithm to the 1979–2013 satellite data reveals that freeze-up is delayed by two weeks per decade for the Chukchi coast and one week per decade for the Beaufort coast. For both regions, break-up start is arriving earlier by 5–7 days per decade and break-up end is arriving earlier by 10–12 days per decade. In the Chukchi Sea, “early” break-up is arriving earlier by one month over the 34-year period and alternates with a “late” break-up. The calculated freeze-up and break-up dates provide information helpful to understanding the dynamics of the annual sea-ice cycle and identifying the drivers that modify this cycle. The algorithm presented here, and potential refinements, can help guide future work on changes in the seasonal cycle of sea ice. The sea-ice phenology of freeze-up and break-up that results from our approach is consistent with observations of sea-ice use. It may be applied to advancing our understanding and prediction of the timing of seasonal navigation, availability of ice as a biological habitat, and assessment of numerical models.

  15. Effects of changing sea ice on marine mammals and subsistence hunters in northern Alaska from traditional knowledge interviews.

    Science.gov (United States)

    Huntington, Henry P; Quakenbush, Lori T; Nelson, Mark

    2016-08-01

    Marine mammals are important sources of food for indigenous residents of northern Alaska. Changing sea ice patterns affect the animals themselves as well as access to them by hunters. Documenting the traditional knowledge of Iñupiaq and Yupik hunters concerning marine mammals and sea ice makes accessible a wide range of information relevant to understanding the ecosystem to which humans belong. We interviewed hunters in 11 coastal villages from the northern Bering Sea to the Beaufort Sea. Hunters reported extensive changes in sea ice and weather that have affected the timing of marine mammal migrations, their distribution and behaviour and the efficacy of certain hunting methods. Amidst these changes, however, hunters cited offsetting technological benefits, such as more powerful and fuel-efficient outboard engines. Other concerns included potential impacts to subsistence hunting from industrial activity such as shipping and oil and gas development. While hunters have been able to adjust to some changes, continued environmental changes and increased disturbance from human activity may further challenge their ability to acquire food in the future. There are indications, however, that innovation and flexibility provide sources of resilience.

  16. White sea radioactivity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Aliev, R.A. [Lomonosov Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics]|[Lomonosov Moscow State Univ. (Russian Federation). Chemistry Dept.]|[Russian Academy of Sciences, Moscow (Russian Federation). Shirshov Inst. of Oceanology; Kalmykov, S.N.; Lisitzin, A.P. [Lomonosov Moscow State Univ. (Russian Federation). Chemistry Dept.

    2004-07-01

    The aim of the present work is to estimate potential sources and chronology of pollution of the White Sea (Russia) by artificial radionuclides. White Sea is semi-closed water body connected with Barents Sea by a narrow strait. Thus, pollution of White Sea may be caused by highly polluted Barents waters and river (mainly Northern Dvina) run-off. This is the first detailed investigation of radioactivity of White Sea sediment records. (orig.)

  17. 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.

  18. 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

  19. 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...

  20. 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...

  1. 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...

  2. 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.

  3. 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.

  4. Inter-population movements of steller sea lions in Alaska with implications for population separation.

    Directory of Open Access Journals (Sweden)

    Lauri A Jemison

    Full Text Available Genetic studies and differing population trends support the separation of Steller sea lions (Eumetopias jubatus into a western distinct population segment (WDPS and an eastern DPS (EDPS with the dividing line between populations at 144° W. Despite little exchange for thousands of years, the gap between the breeding ranges narrowed during the past 15-30 years with the formation of new rookeries near the DPS boundary. We analyzed >22,000 sightings of 4,172 sea lions branded as pups in each DPS from 2000-2010 to estimate probabilities of a sea lion born in one DPS being seen within the range of the other DPS (either 'West' or 'East'. Males from both populations regularly traveled across the DPS boundary; probabilities were highest at ages 2-5 and for males born in Prince William Sound and southern Southeast Alaska. The probability of WDPS females being in the East at age 5 was 0.067 but 0 for EDPS females which rarely traveled to the West. Prince William Sound-born females had high probabilities of being in the East during breeding and non-breeding seasons. We present strong evidence that WDPS females have permanently emigrated to the East, reproducing at two 'mixing zone' rookeries. We documented breeding bulls that traveled >6,500 km round trip from their natal rookery in southern Alaska to the northern Bering Sea and central Aleutian Islands and back within one year. WDPS animals began moving East in the 1990s, following steep population declines in the central Gulf of Alaska. Results of our study, and others documenting high survival and rapid population growth in northern Southeast Alaska suggest that conditions in this mixing zone region have been optimal for sea lions. It is unclear whether eastward movement across the DPS boundary is due to less-optimal conditions in the West or a reflection of favorable conditions in the East.

  5. 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

  6. Modelling the sensitivity of colonially breeding marine birds to oil spills: guillemot and kittiwake populations on the Pribilof Islands, Bering Sea.

    OpenAIRE

    Ford, RG; Wiens, JA; Heinemann, D.; HUNT, GL

    1982-01-01

    Applications of the model to populations of Brunnich's guillemot Uria lomvia, common guillemot U. aalge, red-legged kittiwake Rissa brevirostris, and black-legged kittiwake R. tridactyla breeding on the Pribilof Islands suggest that guillemot mortality is greatest following perturbations located in shallow inshore areas about the breeding islands, while kittiwakes are less severely affected by localized perturbations but are sensitive to spills occurring over a wider area about the islands. M...

  7. 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...

  8. 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...

  9. 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...

  10. BS_Q15.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (15 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  11. BS_Q11.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (11 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  12. BS_Q06.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (6 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  13. BS_Q08.TIF - Bering Sea U.S. EEZ GLORIA sidescan-sonar data mosaic (8 of 30) (LCC, 50 m, Clarke1866)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In 1984, the U.S. Geological Survey (USGS), Office of Marine Geology, launched a program using the Geological LOng-Range Inclined Asdic (GLORIA) sidescan-sonar...

  14. 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 D.; 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.

  15. Acoustic-Trawl Survey of Walleye Pollock on the U.S. and Russian Bering Sea Shelf (DY1207, EK60)

    Data.gov (United States)

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

  16. 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 returns...

  17. 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 (structures, and elevated reactivity (bio- and photo-lability) of spring DOM due to the presence of terrestrial inputs enriched in carbohydrates and aromatic structures.

  18. Selected bibliography on birds in the Bering Sea and the Arctic Ocean as related to outer continental shelf areas under consideration for leasing: Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This bibliography lists published and unpublished references to the bird resources within or near the areas of Alaska's outer continental shelf that have been...

  19. 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...

  20. Underway meteorological, navigational, physical and time series data collected aboard NOAA Ship Ronald H. Brown in the Bering Sea on 2015-09-04 (NCEI Accession 0137446)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0137446 contains raw underway meteorological, navigational, physical and time series data logged by the Scientific Computer System (SCS) aboard NOAA...