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Sample records for volume arctic ocean

  1. Estimation of Volume and Freshwater Flux from the Arctic Ocean using SMAP and NCEP CFSv2

    Science.gov (United States)

    Bulusu, S.

    2017-12-01

    Spatial and temporal monitoring of sea surface salinity (SSS) plays an important role globally and especially over the Arctic Ocean. The Arctic ice melt has led to an influx of freshwater into the Arctic environment, a process that can be observed in SSS. The recently launched NASA's Soil Moisture Active Passive (SMAP) mission is primarily designed for the global monitoring of soil moisture using L- band (1.4GHz) frequency. SMAP also has the capability of measuring SSS and can thus extend the NASA's Aquarius salinity mission (ended June 7, 2015), salinity data record with improved temporal/spatial sampling. In this research an attempt is made to investigate the retrievability of SSS over the Arctic from SMAP satellite. The objectives of this study are to verify the use of SMAP sea surface salinity (and freshwater) variability in the Arctic Ocean and the extent to estimate freshwater, salt and volume flux from the Arctic Ocean. Along with SMAP data we will use NASA's Ice, Cloud,and land Elevation Satellites (ICESat and ICESat-2), and ESA's CryoSat-2, and NASA's Gravity Recovery and Climate Experiment (GRACE) satellites data to estimate ice melt in the Arctic. The preliminary results from SMAP compared well with the NCEP Climate Forecast System version 2 (CFSv2) salinity data in this region capturing patterns fairly well over the Arctic.

  2. Observations of Recent Arctic Sea Ice Volume Loss and Its Impact on Ocean-Atmosphere Energy Exchange and Ice Production

    Science.gov (United States)

    Kurtz, N. T.; Markus, T.; Farrell, S. L.; Worthen, D. L.; Boisvert, L. N.

    2011-01-01

    Using recently developed techniques we estimate snow and sea ice thickness distributions for the Arctic basin through the combination of freeboard data from the Ice, Cloud, and land Elevation Satellite (ICESat) and a snow depth model. These data are used with meteorological data and a thermodynamic sea ice model to calculate ocean-atmosphere heat exchange and ice volume production during the 2003-2008 fall and winter seasons. The calculated heat fluxes and ice growth rates are in agreement with previous observations over multiyear ice. In this study, we calculate heat fluxes and ice growth rates for the full distribution of ice thicknesses covering the Arctic basin and determine the impact of ice thickness change on the calculated values. Thinning of the sea ice is observed which greatly increases the 2005-2007 fall period ocean-atmosphere heat fluxes compared to those observed in 2003. Although there was also a decline in sea ice thickness for the winter periods, the winter time heat flux was found to be less impacted by the observed changes in ice thickness. A large increase in the net Arctic ocean-atmosphere heat output is also observed in the fall periods due to changes in the areal coverage of sea ice. The anomalously low sea ice coverage in 2007 led to a net ocean-atmosphere heat output approximately 3 times greater than was observed in previous years and suggests that sea ice losses are now playing a role in increasing surface air temperatures in the Arctic.

  3. NODC Standard Product: International ocean atlas Volume 6 - Zooplankton of the Arctic Seas 2002 (NODC Accession 0098570)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical and biological data for the Arctic and sub-Arctic regions extending from the Barents Sea to the Northwest Pacific, sampled during 25 scientific cruises for...

  4. Studying ocean acidification in the Arctic Ocean

    Science.gov (United States)

    Robbins, Lisa

    2012-01-01

    The U.S. Geological Survey (USGS) partnership with the U.S. Coast Guard Ice Breaker Healey and its United Nations Convention Law of the Sea (UNCLOS) cruises has produced new synoptic data from samples collected in the Arctic Ocean and insights into the patterns and extent of ocean acidification. This framework of foundational geochemical information will help inform our understanding of potential risks to Arctic resources due to ocean acidification.

  5. U.S. Navy Marine Climatic Atlas of the World. Volume 6. Arctic Ocean

    Science.gov (United States)

    1963-02-01

    Disturbed Circulation of the Arctic osphere. Journal of Meteorology, Vol. 17, No. 1, pp. ; Lancaster. I960. 25. Henry , T. J. G. Maps of Upper...O U D Parcanloga Frvqvtncy ot Prvopnoiion by Month (ol Pwctnloo« of all prcunt w»oth«f’ obiarvaliont rcponrng pr«c> pitotion (b) Pcrcvniog

  6. Changing Arctic Ocean freshwater pathways.

    Science.gov (United States)

    Morison, James; Kwok, Ron; Peralta-Ferriz, Cecilia; Alkire, Matt; Rigor, Ignatius; Andersen, Roger; Steele, Mike

    2012-01-04

    Freshening in the Canada basin of the Arctic Ocean began in the 1990s and continued to at least the end of 2008. By then, the Arctic Ocean might have gained four times as much fresh water as comprised the Great Salinity Anomaly of the 1970s, raising the spectre of slowing global ocean circulation. Freshening has been attributed to increased sea ice melting and contributions from runoff, but a leading explanation has been a strengthening of the Beaufort High--a characteristic peak in sea level atmospheric pressure--which tends to accelerate an anticyclonic (clockwise) wind pattern causing convergence of fresh surface water. Limited observations have made this explanation difficult to verify, and observations of increasing freshwater content under a weakened Beaufort High suggest that other factors must be affecting freshwater content. Here we use observations to show that during a time of record reductions in ice extent from 2005 to 2008, the dominant freshwater content changes were an increase in the Canada basin balanced by a decrease in the Eurasian basin. Observations are drawn from satellite data (sea surface height and ocean-bottom pressure) and in situ data. The freshwater changes were due to a cyclonic (anticlockwise) shift in the ocean pathway of Eurasian runoff forced by strengthening of the west-to-east Northern Hemisphere atmospheric circulation characterized by an increased Arctic Oscillation index. Our results confirm that runoff is an important influence on the Arctic Ocean and establish that the spatial and temporal manifestations of the runoff pathways are modulated by the Arctic Oscillation, rather than the strength of the wind-driven Beaufort Gyre circulation.

  7. AMAP Assessment 2013: Arctic Ocean acidification

    Science.gov (United States)

    2013-01-01

    This assessment report presents the results of the 2013 AMAP Assessment of Arctic Ocean Acidification (AOA). This is the first such assessment dealing with AOA from an Arctic-wide perspective, and complements several assessments that AMAP has delivered over the past ten years concerning the effects of climate change on Arctic ecosystems and people. The Arctic Monitoring and Assessment Programme (AMAP) is a group working under the Arctic Council. The Arctic Council Ministers have requested AMAP to: - produce integrated assessment reports on the status and trends of the conditions of the Arctic ecosystems;

  8. Arctic and Southern Ocean Sea Ice Concentrations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly sea ice concentration for Arctic (1901 to 1995) and Southern oceans (1973 to 1990) were digitized on a standard 1-degree grid (cylindrical projection) to...

  9. Arctic Ocean Regional Climatology (NCEI Accession 0115771)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To provide an improved oceanographic foundation and reference for multi-disciplinary studies of the Arctic Ocean, NCEI developed a new set of high-resolution...

  10. International Regulation of Central Arctic Ocean Fisheries

    NARCIS (Netherlands)

    Molenaar, E.J.

    Due in particular to the impacts of climate change, the adequacy of the international regulation of Central Arctic Ocean fisheries has come under increasing scrutiny in recent years. As shown in this article, however, international regulation of Central Arctic Ocean fisheries is by no means entirely

  11. Late Cenozoic Paleoceanography of the Central Arctic Ocean

    International Nuclear Information System (INIS)

    O'Regan, Matt

    2011-01-01

    The Arctic Ocean is the smallest and perhaps least accessible of the worlds oceans. It occupies only 26% of the global ocean area, and less than 10% of its volume. However, it exerts a disproportionately large influence on the global climate system through a complex set of positive and negative feedback mechanisms directly or indirectly related to terrestrial ice and snow cover and sea ice. Increasingly, the northern high latitude cryosphere is seen as an exceptionally fragile part of the global climate system, a fact exemplified by observed reductions in sea ice extent during the past decades [2]. The paleoceanographic evolution of the Arctic Ocean can provide important insights into the physical forcing mechanisms that affect the form, intensity and permanence of ice in the high Arctic, and its sensitivity to these mechanisms in vastly different climate states of the past. However, marine records capturing the late Cenozoic paleoceanography of the Arctic are limited - most notably because only a single deep borehole exists from the central parts of this Ocean. This paper reviews the principal late Cenozoic (Neogene/Quaternary) results from the Arctic Coring Expedition to the Lomonosov Ridge and in light of recent data and observations on modern sea ice, outlines emerging questions related to three main themes: 1) the establishment of the 'modern' Arctic Ocean and the opening of the Fram Strait 2) the inception of perennial sea ice 3) The Quaternary intensification of Northern Hemisphere glaciations.

  12. Arctic Ocean data in CARINA

    Directory of Open Access Journals (Sweden)

    S. Jutterström

    2010-02-01

    Full Text Available The paper describes the steps taken for quality controlling chosen parameters within the Arctic Ocean data included in the CARINA data set and checking for offsets between the individual cruises. The evaluated parameters are the inorganic carbon parameters (total dissolved inorganic carbon, total alkalinity and pH, oxygen and nutrients: nitrate, phosphate and silicate. More parameters can be found in the CARINA data product, but were not subject to a secondary quality control. The main method in determining offsets between cruises was regional multi-linear regression, after a first rough basin-wide deep-water estimate of each parameter. Lastly, the results of the secondary quality control are discussed as well as applied adjustments.

  13. Hydrochemical Atlas of the Arctic Ocean (NODC Accession 0044630)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The present Hydrochemical Atlas of the Arctic Ocean is a description of hydrochemical conditions in the Arctic Ocean on the basis of a greater body of hydrochemical...

  14. The great challenges in Arctic Ocean paleoceanography

    International Nuclear Information System (INIS)

    Stein, Ruediger

    2011-01-01

    Despite the importance of the Arctic in the climate system, the data base we have from this area is still very weak, and large parts of the climate history have not been recovered at all in sedimentary sections. In order to fill this gap in knowledge, international, multidisciplinary expeditions and projects for scientific drilling/coring in the Arctic Ocean are needed. Key areas and approaches for drilling and recovering undisturbed and complete sedimentary sequences are depth transects across the major ocean ridge systems, i.e., the Lomonosov Ridge, the Alpha-Mendeleev Ridge, and the Chukchi Plateau/Northwind Ridge, the Beaufort, Kara and Laptev sea continental margins, as well as the major Arctic gateways towards the Atlantic and Pacific oceans. The new detailed climate records from the Arctic Ocean spanning time intervals from the Late Cretaceous/Paleogene Greenhouse world to the Neogene-Quaternary Icehouse world and representing short- and long-term climate variability on scales from 10 to 10 6 years, will give new insights into our understanding of the Arctic Ocean within the global climate system and provide an opportunity to test the performance of climate models used to predict future climate change. With this, studying the Arctic Ocean is certainly one of the major challenges in climate research for the coming decades.

  15. Environmental marine geology of the Arctic Ocean

    International Nuclear Information System (INIS)

    Mudie, P.J.

    1991-01-01

    The Arctic Ocean and its ice cover are major regulators of Northern Hemisphere climate, ocean circulation and marine productivity. The Arctic is also very sensitive to changes in the global environment because sea ice magnifies small changes in temperature, and because polar regions are sinks for air pollutants. Marine geology studies are being carried out to determine the nature and rate of these environmental changes by study of modem ice and sea-bed environments, and by interpretation of geological records imprinted in the sea-floor sediments. Sea ice camps, an ice island, and polar icebreakers have been used to study both western and eastern Arctic Ocean basins. Possible early warning signals of environmental changes in the Canadian Arctic are die-back in Arctic sponge reefs, outbreaks of toxic dinoflagellates, and pesticides in the marine food chain. Eastern Arctic ice and surface waters are contaminated by freon and radioactive fallout from Chernobyl. At present, different sedimentary processes operate in the pack ice-covered Canadian polar margin than in summer open waters off Alaska and Eurasia. The geological records, however, suggest that a temperature increase of 1-4 degree C would result in summer open water throughout the Arctic, with major changes in ocean circulation and productivity of waters off Eastern North America, and more widespread transport of pollutants from eastern to western Arctic basins. More studies of longer sediment cores are needed to confirm these interpretations, but is is now clear that the Arctic Ocean has been the pacemaker of climate change during the past 1 million years

  16. Arctic Ocean Paleoceanography and Future IODP Drilling

    Science.gov (United States)

    Stein, Ruediger

    2015-04-01

    Although the Arctic Ocean is a major player in the global climate/earth system, this region is one of the last major physiographic provinces on Earth where the short- and long-term geological history is still poorly known. This lack in knowledge is mainly due to the major technological/logistical problems in operating within the permanently ice-covered Arctic region which makes it difficult to retrieve long and undisturbed sediment cores. Prior to 2004, in the central Arctic Ocean piston and gravity coring was mainly restricted to obtaining near-surface sediments, i.e., only the upper 15 m could be sampled. Thus, all studies were restricted to the late Pliocene/Quaternary time interval, with a few exceptions. These include the four short cores obtained by gravity coring from drifting ice floes over the Alpha Ridge, where older pre-Neogene organic-carbon-rich muds and laminated biosiliceous oozes were sampled. Continuous central Arctic Ocean sedimentary records, allowing a development of chronologic sequences of climate and environmental change through Cenozoic times and a comparison with global climate records, however, were missing prior to the IODP Expedition 302 (Arctic Ocean Coring Expedition - ACEX), the first scientific drilling in the central Arctic Ocean. By studying the unique ACEX sequence, a large number of scientific discoveries that describe previously unknown Arctic paleoenvironments, were obtained during the last decade (for most recent review and references see Stein et al., 2014). While these results from ACEX were unprecedented, key questions related to the climate history of the Arctic Ocean remain unanswered, in part because of poor core recovery, and in part because of the possible presence of a major mid-Cenozoic hiatus or interval of starved sedimentation within the ACEX record. In order to fill this gap in knowledge, international, multidisciplinary expeditions and projects for scientific drilling/coring in the Arctic Ocean are needed. Key

  17. Mean Dynamic Topography of the Arctic Ocean

    Science.gov (United States)

    Farrell, Sinead Louise; Mcadoo, David C.; Laxon, Seymour W.; Zwally, H. Jay; Yi, Donghui; Ridout, Andy; Giles, Katherine

    2012-01-01

    ICESat and Envisat altimetry data provide measurements of the instantaneous sea surface height (SSH) across the Arctic Ocean, using lead and open water elevation within the sea ice pack. First, these data were used to derive two independent mean sea surface (MSS) models by stacking and averaging along-track SSH profiles gathered between 2003 and 2009. The ICESat and Envisat MSS data were combined to construct the high-resolution ICEn MSS. Second, we estimate the 5.5-year mean dynamic topography (MDT) of the Arctic Ocean by differencing the ICEn MSS with the new GOCO02S geoid model, derived from GRACE and GOCE gravity. Using these satellite-only data we map the major features of Arctic Ocean dynamical height that are consistent with in situ observations, including the topographical highs and lows of the Beaufort and Greenland Gyres, respectively. Smaller-scale MDT structures remain largely unresolved due to uncertainties in the geoid at short wavelengths.

  18. Arctic Ocean Scientific Drilling: The Next Frontier

    Directory of Open Access Journals (Sweden)

    Ruediger Stein

    2010-04-01

    Full Text Available The modern Arctic Ocean appears to be changing faster than any other region on Earth. To understand the potential extent of high latitude climate change, it is necessary to sample the history stored in the sediments filling the basins and covering the ridges of the Arctic Ocean. These sediments have been imaged with seismic reflection data, but except for the superficial record, which has been piston cored, they have been sampled only on the Lomonosov Ridge in 2004 during the Arctic Coring Expedition (ACEX-IODP Leg 302; Backman et al., 2006 and in 1993 in the ice-free waters in the Fram Strait/Yermak Plateau area (ODP Leg 151; Thiede et al., 1996.Although major progress in Arctic Ocean research has been made during the last few decades, the short- and long-term paleoceanographic and paleoclimatic history as well as its plate-tectonic evolution are poorly known compared to the other oceans. Despite the importance of the Arctic in the climate system, the database we have from this area is still very weak. Large segments of geologic time have not been sampled in sedimentary sections. The question of regional variations cannot be addressed.

  19. Nudging the Arctic Ocean to quantify Arctic sea ice feedbacks

    Science.gov (United States)

    Dekker, Evelien; Severijns, Camiel; Bintanja, Richard

    2017-04-01

    It is well-established that the Arctic is warming 2 to 3 time faster than rest of the planet. One of the great uncertainties in climate research is related to what extent sea ice feedbacks amplify this (seasonally varying) Arctic warming. Earlier studies have analyzed existing climate model output using correlations and energy budget considerations in order to quantify sea ice feedbacks through indirect methods. From these analyses it is regularly inferred that sea ice likely plays an important role, but details remain obscure. Here we will take a different and a more direct approach: we will keep the sea ice constant in a sensitivity simulation, using a state-of -the-art climate model (EC-Earth), applying a technique that has never been attempted before. This experimental technique involves nudging the temperature and salinity of the ocean surface (and possibly some layers below to maintain the vertical structure and mixing) to a predefined prescribed state. When strongly nudged to existing (seasonally-varying) sea surface temperatures, ocean salinity and temperature, we force the sea ice to remain in regions/seasons where it is located in the prescribed state, despite the changing climate. Once we obtain fixed' sea ice, we will run a future scenario, for instance 2 x CO2 with and without prescribed sea ice, with the difference between these runs providing a measure as to what extent sea ice contributes to Arctic warming, including the seasonal and geographical imprint of the effects.

  20. Arctic Ocean circulation during the anoxic Eocene Azolla event

    Science.gov (United States)

    Speelman, Eveline; Sinninghe Damsté, Jaap; März, Christian; Brumsack, Hans; Reichart, Gert-Jan

    2010-05-01

    through seawater inflow). Excess vanadium accumulation during the Azolla event (80 ppm), basin volume and surface area, average vanadium sea (1.8 ppb) and river water (1.0 ppb) concentrations, together indicate that an inflow of Nordic Sea water of 0.2 Sv is needed to sustain vanadium levels. The same calculation using molybdenum gives an inflow of only 0.02 Sv. These low inflow rates imply Arctic Ocean (deep) water residence times of 2000 - 20000 years, respectively. Based on climate modeling we calculated a summed net amount of precipitation for the Eocene Arctic Basin (Precipitation - Evaporation + Runoff) of 0.46 Sv. Together these notions indicate that a compensating inflow of saline North Atlantic water occurred, accompanied by an outflow of more fresh waters, resulting in a bi-directional, two-layer flow through the (proto-) Fram Strait. Consequently, the limited exchange of water through the Fram Strait implies that a relatively low export productivity would have been sufficient to render Arctic bottom waters anoxic. Jakobsson, M., Backman, J., Rudels, B., Nycander, J., Frank, M., Mayer, L., Jokat, W., Sangiorgi, F., O'Regan, M., Brinkhuis, H., King, J., Moran, K. (2007). The early Miocene onset of a ventilated circulation regimen in the Arctic Ocean. Nature 447, 986-990.

  1. Mercury genomics in the Arctic Ocean

    Science.gov (United States)

    Bowman, K.; Lamborg, C. H.; Collins, E.; Hammerschmidt, C. R.; Agather, A. M.

    2017-12-01

    Methyl-mercury production in the ocean is likely dependent on microbial activity, however, methylation pathways remain elusive. In the Arctic, high concentrations of methyl-mercury are found in top predator marine mammals and seabirds. As a result of seafood consumption, pregnant women and women of child-bearing age in the Arctic often have blood Hg concentrations that exceed U.S. and Canadian safety guidelines. To understand the chemical cycling of mercury in the Arctic Ocean we participated in the 2015 U.S. GEOTRACES Arctic expedition (GN01) to measure Hg speciation in the water column of the Bering Sea, Makarov basin, and Canada basin between Dutch Harbor, Alaska and the North Pole. At select stations, seawater was filtered through 0.22 µm Sterivex filters and genomic DNA was collected using a phenol-chloroform extraction. Broad-range degenerate PCR primers were used to detect the presence of hgcAB, and clade-specific degenerate quantitative PCR primers were used to determine the abundance of hgcA. Metagenomic sequencing was done at three stations to identify taxonomic and functional groups, and to search for hgcA-like genes that the PCR primers may have missed.

  2. Calcareous microfossil-based orbital cyclostratigraphy in the Arctic Ocean

    Science.gov (United States)

    Marzen, Rachel; DeNinno, Lauren H.; Cronin, Thomas M.

    2016-01-01

    Microfaunal and geochemical proxies from marine sediment records from central Arctic Ocean (CAO) submarine ridges suggest a close relationship over the last 550 thousand years (kyr) between orbital-scale climatic oscillations, sea-ice cover, marine biological productivity and other parameters. Multiple paleoclimate proxies record glacial to interglacial cycles. To understand the climate-cryosphere-productivity relationship, we examined the cyclostratigraphy of calcareous microfossils and constructed a composite Arctic Paleoclimate Index (API) "stack" from benthic foraminiferal and ostracode density from 14 sediment cores. Following the hypothesis that API is driven mainly by changes in sea-ice related productivity, the API stack shows the Arctic experienced a series of highly productive interglacials and interstadials every ∼20 kyr. These periods signify minimal ice shelf and sea-ice cover and maximum marine productivity. Rapid transitions in productivity are seen during shifts from interglacial to glacial climate states. Discrepancies between the Arctic API curves and various global climatic, sea-level and ice-volume curves suggest abrupt growth and decay of Arctic ice shelves related to climatic and sea level oscillations.

  3. Cesium-137 contamination in Arctic Ocean ice

    International Nuclear Information System (INIS)

    Meese, D.; Tucker, W.; Cooper, L.; Larsen, I.L.; Grebmeier, J.

    1995-01-01

    Sea ice and ice-borne sediment samples were collected across the western Arctic basin on the joint US/Canada Arctic Ocean Section during August 1994. Samples were processed on board and returned at the completion of the cruise to Oak Ridge National Laboratory for analysis. Sediment was observed on the surface and in the ice from the southern ice limit in the Chukchi Sea to the North Pole. Preliminary results on the ice-borne sediment samples show widespread elevated concentrations of 137 Cs, ranging from 4.9 to 73 mBq g dry weight -1 . An analysis of the measurements indicate that sea ice is primary transport mechanism by which contaminated sediments are redistributed throughout the Arctic Ocean and possibly exported into the Greenland Sea and North Atlantic through Fram Strait. The wide variability in the ice-borne sediment concentrations of 137 Cs measured along the transect argues that contaminants incorporated on the Siberian shelves can follow much more variable trajectories than is suggested by mean ice drift calculations. 2 figs

  4. Diurnal tides in the Arctic Ocean

    Science.gov (United States)

    Kowalik, Z.; Proshutinsky, A. Y.

    1993-01-01

    A 2D numerical model with a space grid of about 14 km is applied to calculate diurnal tidal constituents K(1) and O(1) in the Arctic Ocean. Calculated corange and cotidal charts show that along the continental slope, local regions of increased sea level amplitude, highly variable phase and enhanced currents occur. It is shown that in these local regions, shelf waves (topographic waves) of tidal origin are generated. In the Arctic Ocean and Northern Atlantic Ocean more than 30 regions of enhanced currents are identified. To prove the near-resonant interaction of the diurnal tides with the local bottom topography, the natural periods of oscillations for all regions have been calculated. The flux of energy averaged over the tidal period depicts the gyres of semitrapped energy, suggesting that the shelf waves are partially trapped over the irregularities of the bottom topography. It is shown that the occurrence of near-resonance phenomenon changes the energy flow in the tidal waves. First, the flux of energy from the astronomical sources is amplified in the shelf wave regions, and afterwards the tidal energy is strongly dissipated in the same regions.

  5. Arctic Ocean Model Intercomparison Using Sound Speed

    Science.gov (United States)

    Dukhovskoy, D. S.; Johnson, M. A.

    2002-05-01

    The monthly and annual means from three Arctic ocean - sea ice climate model simulations are compared for the period 1979-1997. Sound speed is used to integrate model outputs of temperature and salinity along a section between Barrow and Franz Josef Land. A statistical approach is used to test for differences among the three models for two basic data subsets. We integrated and then analyzed an upper layer between 2 m - 50 m, and also a deep layer from 500 m to the bottom. The deep layer is characterized by low time-variability. No high-frequency signals appear in the deep layer having been filtered out in the upper layer. There is no seasonal signal in the deep layer and the monthly means insignificantly oscillate about the long-period mean. For the deep ocean the long-period mean can be considered quasi-constant, at least within the 19 year period of our analysis. Thus we assumed that the deep ocean would be the best choice for comparing the means of the model outputs. The upper (mixed) layer was chosen to contrast the deep layer dynamics. There are distinct seasonal and interannual signals in the sound speed time series in this layer. The mixed layer is a major link in the ocean - air interaction mechanism. Thus, different mean states of the upper layer in the models might cause different responses in other components of the Arctic climate system. The upper layer also strongly reflects any differences in atmosphere forcing. To compare data from the three models we have used a one-way t-test for the population mean, the Wilcoxon one-sample signed-rank test (when the requirement of normality of tested data is violated), and one-way ANOVA method and F-test to verify our hypothesis that the model outputs have the same mean sound speed. The different statistical approaches have shown that all models have different mean characteristics of the deep and upper layers of the Arctic Ocean.

  6. Ship Track for The Hidden Ocean Arctic 2005 - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ship track of the US Coast Guard icebreaker Healy during the "Hidden Ocean Arctic 2005" expedition sponsored by the National Oceanic and Atmospheric Administration...

  7. Radioactive dumping in the Arctic Ocean

    International Nuclear Information System (INIS)

    Lamb, J.; Gizewski, P.

    1993-01-01

    Recent revelations concerning the possible environmental hazards posed by the sunken Soviet nuclear submarine Komsomolets and the disposal of radioactive materials in the Arctic and North Atlantic oceans have generated much controversy and debate. Too often, however, the key scientific and policy issues that the dumping raises are treated as two solitudes. In reality, decisions taken by national governments and international agencies in connection with remediation, regulation, and even research must be based on both science and policy. Indeed, a sound approach to the dumping issue must integrate scientific evidence and policy considerations relating to legal, political, social, and economic matters. Radioactive waste disposal is an exceedingly difficult problem. Information detailing the Soviet Navy's past dumping practices, and increasing awareness of the problems that Russia and other states may encounter in the future disposal of radioactive waste, indicate that the global inventory of radioactive wastes requiring storage and disposal is large and growing

  8. Consequences of future increased Arctic runoff on Arctic Ocean stratification, circulation, and sea ice cover

    OpenAIRE

    Nummelin, Aleksi; Ilicak, Mehmet; Li, Camille; Smedsrud, Lars Henrik

    2016-01-01

    The Arctic Ocean has important freshwater sources including river runoff, low evaporation, and exchange with the Pacific Ocean. In the future, we expect even larger freshwater input as the global hydrological cycle accelerates, increasing high-latitude precipitation, and river runoff. Previous modeling studies show some robust responses to high-latitude freshwater perturbations, including a strengthening of Arctic stratification and a weakening of the large-scale ocean circulation...

  9. Organophosphate Ester Flame Retardants and Plasticizers in Ocean Sediments from the North Pacific to the Arctic Ocean.

    Science.gov (United States)

    Ma, Yuxin; Xie, Zhiyong; Lohmann, Rainer; Mi, Wenying; Gao, Guoping

    2017-04-04

    The presence of organophosphate ester (OPE) flame retardants and plasticizers in surface sediment from the North Pacific to Arctic Ocean was observed for the first time during the fourth National Arctic Research Expedition of China in the summer of 2010. The samples were analyzed for three halogenated OPEs [tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), and tris(dichloroisopropyl) phosphate], three alkylated OPEs [triisobutyl phosphate (TiBP), tri-n-butyl phosphate, and tripentyl phosphate], and triphenyl phosphate. Σ 7 OPEs (total concentration of the observed OPEs) was in the range of 159-4658 pg/g of dry weight. Halogenated OPEs were generally more abundant than the nonhalogenated OPEs; TCEP and TiBP dominated the overall concentrations. Except for that of the Bering Sea, Σ 7 OPEs values increased with increasing latitudes from Bering Strait to the Central Arctic Ocean, while the contributions of halogenated OPEs (typically TCEP and TCPP) to the total OPE profile also increased from the Bering Strait to the Central Arctic Ocean, indicating they are more likely to be transported to the remote Arctic. The median budget of 52 (range of 17-292) tons for Σ 7 OPEs in sediment from the Central Arctic Ocean represents only a very small amount of their total production volume, yet the amount of OPEs in Arctic Ocean sediment was significantly larger than the sum of polybrominated diphenyl ethers (PBDEs) in the sediment, indicating they are equally prone to long-range transport away from source regions. Given the increasing level of production and usage of OPEs as substitutes of PBDEs, OPEs will continue to accumulate in the remote Arctic.

  10. Increase in acidifying water in the western Arctic Ocean

    Science.gov (United States)

    Qi, Di; Chen, Liqi; Chen, Baoshan; Gao, Zhongyong; Zhong, Wenli; Feely, Richard A.; Anderson, Leif G.; Sun, Heng; Chen, Jianfang; Chen, Min; Zhan, Liyang; Zhang, Yuanhui; Cai, Wei-Jun

    2017-02-01

    The uptake of anthropogenic CO2 by the ocean decreases seawater pH and carbonate mineral aragonite saturation state (Ωarag), a process known as Ocean Acidification (OA). This can be detrimental to marine organisms and ecosystems. The Arctic Ocean is particularly sensitive to climate change and aragonite is expected to become undersaturated (Ωarag Pacific Winter Water transport, driven by an anomalous circulation pattern and sea-ice retreat, is primarily responsible for the expansion, although local carbon recycling and anthropogenic CO2 uptake have also contributed. These results indicate more rapid acidification is occurring in the Arctic Ocean than the Pacific and Atlantic oceans, with the western Arctic Ocean the first open-ocean region with large-scale expansion of `acidified’ water directly observed in the upper water column.

  11. Anthropogenic radionuclides in the Arctic Ocean. Distribution and pathways

    International Nuclear Information System (INIS)

    Josefsson, Dan

    1998-05-01

    Anthropogenic radionuclide concentrations have been determined in seawater and sediment samples collected in 1991, 1994 and 1996 in the Eurasian Arctic shelf and interior. Global fallout, releases from European reprocessing plants and the Chernobyl accident are identified as the three main sources. From measurements in the Eurasian shelf seas it is concluded that the total input of 134 Cs, 137 Cs and 90 Sr from these sources has been decreasing during the 1990's, while 129 I has increased. The main fraction of the reprocessing and Chernobyl activity found in Arctic Ocean surface layer is transported from the Barents Sea east along the Eurasian Arctic shelf seas to the Laptev Sea before entering the Nansen Basin. This inflow results in highest 137 Cs, 129 I and 90 Sr concentrations in the Arctic Ocean surface layers, and continuously decreasing concentrations with depth. Chernobyl-derived 137 Cs appeared in the central parts of the Arctic Ocean around 1991, and in the mid 1990's the fraction to total 137 Cs was approximately 30% in the entire Eurasian Arctic region. The transfer times for releases from Sellafield are estimated to be 5-7 years to the SE Barents Sea, 7-9 years to the Kara Sea, 10-11 years to the Laptev Sea and 12-14 years to the central Arctic Ocean. Global fallout is the primary source of plutonium with highest concentrations found in the Atlantic layer of the Arctic Ocean. When transported over the shallow shelf seas, particle reactive transuranic elements experience an intense scavenging. A rough estimate shows that approximately 75% of the plutonium entering the Kara and Laptev Seas are removed to the sediment. High seasonal riverine input of 239 , 240 Pu is observed near the mouths of the large Russian rivers. Sediment inventories show much higher concentrations on the shelf compared to the deep Arctic Ocean. This is primarily due to the low particle flux in the open ocean

  12. Comprehensive Ocean - Atmosphere Data Set (COADS) LMRF Arctic Subset

    Data.gov (United States)

    National Aeronautics and Space Administration — The Comprehensive Ocean - Atmosphere Data Set (COADS) LMRF Arctic subset contains marine surface weather reports for the region north of 65 degrees N from ships,...

  13. Ship Sensor Observations for The Hidden Ocean Arctic 2005 - Office of Ocean Exploration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly measurements made by selected ship sensors on the US Coast Guard icebreaker Healy during the "The Hidden Ocean Arctic 2005" expedition sponsored by the...

  14. Late Cretaceous seasonal ocean variability from the Arctic.

    Science.gov (United States)

    Davies, Andrew; Kemp, Alan E S; Pike, Jennifer

    2009-07-09

    The modern Arctic Ocean is regarded as a barometer of global change and amplifier of global warming and therefore records of past Arctic change are critical for palaeoclimate reconstruction. Little is known of the state of the Arctic Ocean in the greenhouse period of the Late Cretaceous epoch (65-99 million years ago), yet records from such times may yield important clues to Arctic Ocean behaviour in near-future warmer climates. Here we present a seasonally resolved Cretaceous sedimentary record from the Alpha ridge of the Arctic Ocean. This palaeo-sediment trap provides new insight into the workings of the Cretaceous marine biological carbon pump. Seasonal primary production was dominated by diatom algae but was not related to upwelling as was previously hypothesized. Rather, production occurred within a stratified water column, involving specially adapted species in blooms resembling those of the modern North Pacific subtropical gyre, or those indicated for the Mediterranean sapropels. With increased CO(2) levels and warming currently driving increased stratification in the global ocean, this style of production that is adapted to stratification may become more widespread. Our evidence for seasonal diatom production and flux testify to an ice-free summer, but thin accumulations of terrigenous sediment within the diatom ooze are consistent with the presence of intermittent sea ice in the winter, supporting a wide body of evidence for low temperatures in the Late Cretaceous Arctic Ocean, rather than recent suggestions of a 15 degrees C mean annual temperature at this time.

  15. 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.

  16. Anthropogenic radionuclides in the Arctic Ocean. Distribution and pathways

    Energy Technology Data Exchange (ETDEWEB)

    Josefsson, Dan

    1998-05-01

    Anthropogenic radionuclide concentrations have been determined in seawater and sediment samples collected in 1991, 1994 and 1996 in the Eurasian Arctic shelf and interior. Global fallout, releases from European reprocessing plants and the Chernobyl accident are identified as the three main sources. From measurements in the Eurasian shelf seas it is concluded that the total input of {sup 134}Cs, {sup 137}Cs and {sup 90}Sr from these sources has been decreasing during the 1990`s, while {sup 129}I has increased. The main fraction of the reprocessing and Chernobyl activity found in Arctic Ocean surface layer is transported from the Barents Sea east along the Eurasian Arctic shelf seas to the Laptev Sea before entering the Nansen Basin. This inflow results in highest {sup 137}Cs, {sup 129}I and {sup 90}Sr concentrations in the Arctic Ocean surface layers, and continuously decreasing concentrations with depth. Chernobyl-derived {sup 137}Cs appeared in the central parts of the Arctic Ocean around 1991, and in the mid 1990`s the fraction to total {sup 137}Cs was approximately 30% in the entire Eurasian Arctic region. The transfer times for releases from Sellafield are estimated to be 5-7 years to the SE Barents Sea, 7-9 years to the Kara Sea, 10-11 years to the Laptev Sea and 12-14 years to the central Arctic Ocean. Global fallout is the primary source of plutonium with highest concentrations found in the Atlantic layer of the Arctic Ocean. When transported over the shallow shelf seas, particle reactive transuranic elements experience an intense scavenging. A rough estimate shows that approximately 75% of the plutonium entering the Kara and Laptev Seas are removed to the sediment. High seasonal riverine input of {sup 239}, {sup 240}Pu is observed near the mouths of the large Russian rivers. Sediment inventories show much higher concentrations on the shelf compared to the deep Arctic Ocean. This is primarily due to the low particle flux in the open ocean

  17. Dissolved Organic Matter Land-Ocean Linkages in the Arctic

    Science.gov (United States)

    Mann, P. J.; Spencer, R. M.; Hernes, P. J.; Tank, S. E.; Striegl, R.; Dyda, R. Y.; Peterson, B. J.; McClelland, J. W.; Holmes, R. M.

    2012-04-01

    Rivers draining into the Arctic Ocean exhibit high concentrations of terrigenous dissolved organic carbon (DOC), and recent studies indicate that DOC export is changing due to climatic warming and alteration in permafrost condition. The fate of exported DOC in the Arctic Ocean is important for understanding the regional carbon cycle and remains a point of discussion in the literature. As part of the NSF funded Arctic Great Rivers Observatory (Arctic-GRO) project, samples were collected for DOC, chromophoric and fluorescent dissolved organic matter (CDOM & FDOM) and lignin phenols from the Ob', Yenisey, Lena, Kolyma, Mackenzie and Yukon rivers in 2009 - 2010. DOC and lignin concentrations were elevated during the spring freshet and measurements related to DOC composition indicated an increasing contribution from terrestrial vascular plant sources at this time of year (e.g. lignin carbon-normalized yield, CDOM spectral slope, SUVA254, humic-like fluorescence). CDOM absorption was found to correlate strongly with both DOC (r2=0.83) and lignin concentration (r2=0.92) across the major arctic rivers. Lignin composition was also successfully modeled using FDOM measurements decomposed using PARAFAC analysis. Utilizing these relationships we modeled loads for DOC and lignin export from high-resolution CDOM measurements (daily across the freshet) to derive improved flux estimates, particularly from the dynamic spring discharge maxima period when the majority of DOC and lignin export occurs. The new load estimates for DOC and lignin are higher than previous evaluations, emphasizing that if these are more representative of current arctic riverine export, terrigenous DOC is transiting through the Arctic Ocean at a faster rate than previously thought. It is apparent that higher resolution sampling of arctic rivers is exceptionally valuable with respect to deriving accurate fluxes and we highlight the potential of CDOM in this role for future studies and the applicability of in

  18. On the Arctic Ocean ice thickness response to changes in the external forcing

    Energy Technology Data Exchange (ETDEWEB)

    Stranne, Christian; Bjoerk, Goeran [University of Gothenburg, Department of Earth Sciences, Box 460, Goeteborg (Sweden)

    2012-12-15

    Submarine and satellite observations show that the Arctic Ocean ice cover has undergone a large thickness reduction and a decrease in the areal extent during the last decades. Here the response of the Arctic Ocean ice cover to changes in the poleward atmospheric energy transport, F{sub wall}, is investigated using coupled atmosphere-ice-ocean column models. Two models with highly different complexity are used in order to illustrate the importance of different internal processes and the results highlight the dramatic effects of the negative ice thickness - ice volume export feedback and the positive surface albedo feedback. The steady state ice thickness as a function of F{sub wall} is determined for various model setups and defines what we call ice thickness response curves. When a variable surface albedo and snow precipitation is included, a complex response curve appears with two distinct regimes: a perennial ice cover regime with a fairly linear response and a less responsive seasonal ice cover regime. The two regimes are separated by a steep transition associated with surface albedo feedback. The associated hysteresis is however small, indicating that the Arctic climate system does not have an irreversible tipping point behaviour related to the surface albedo feedback. The results are discussed in the context of the recent reduction of the Arctic sea ice cover. A new mechanism related to regional and temporal variations of the ice divergence within the Arctic Ocean is presented as an explanation for the observed regional variation of the ice thickness reduction. Our results further suggest that the recent reduction in areal ice extent and loss of multiyear ice is related to the albedo dependent transition between seasonal and perennial ice i.e. large areas of the Arctic Ocean that has previously been dominated by multiyear ice might have been pushed below a critical mean ice thickness, corresponding to the above mentioned transition, and into a state dominated

  19. Modes of Arctic Ocean Change from GRACE, ICESat and the PIOMAS and ECCO2 Models of the Arctic Ocean

    Science.gov (United States)

    Peralta Ferriz, C.; Morison, J. H.; Bonin, J. A.; Chambers, D. P.; Kwok, R.; Zhang, J.

    2012-12-01

    EOF analysis of month-to-month variations in GRACE derived Arctic Ocean bottom pressure (OBP) with trend and seasonal variation removed yield three dominant modes. The first mode is a basin wide variation in mass associated with high atmospheric pressure (SLP) over Scandinavia mainly in winter. The second mode is a shift of mass from the central Arctic Ocean to the Siberian shelves due to low pressure over the basins, associated with the Arctic Oscillation. The third mode is a shift in mass between the Eastern and Western Siberian shelves, related to strength of the Beaufort High mainly in summer, and to eastward alongshore winds on the Barents Sea in winter. The PIOMAS and ECCO2 modeled OBP show fair agreement with the form of these modes and provide context in terms of variations in sea surface height SSH. Comparing GRACE OBP from 2007 to 2011 with GRACE OBP from 2002 to 2006 reveals a rising trend over most of the Arctic Ocean but declines in the Kara Sea region and summer East Siberian Sea. ECCO2 bears a faint resemblance to the observed OBP change but appears to be biased negatively. In contrast, PIOMAS SSH and ECCO2 especially, show changes between the two periods that are muted but similar to ICESat dynamic ocean topography and GRACE-ICESat freshwater trends from 2005 through 2008 [Morison et al., 2012] with a rising DOT and freshening in the Beaufort Sea and a trough with decreased freshwater on the Russian side of the Arctic Ocean. Morison, J., R. Kwok, C. Peralta-Ferriz, M. Alkire, I. Rigor, R. Andersen, and M. Steele (2012), Changing Arctic Ocean freshwater pathways, Nature, 481(7379), 66-70.

  20. Arctic-COLORS (Coastal Land Ocean Interactions in the Arctic) - a NASA field campaign scoping study to examine land-ocean interactions in the Arctic

    Science.gov (United States)

    Hernes, P.; Tzortziou, M.; Salisbury, J.; Mannino, A.; Matrai, P.; Friedrichs, M. A.; Del Castillo, C. E.

    2014-12-01

    The Arctic region is warming faster than anywhere else on the planet, triggering rapid social and economic changes and impacting both terrestrial and marine ecosystems. Yet our understanding of critical processes and interactions along the Arctic land-ocean interface is limited. Arctic-COLORS is a Field Campaign Scoping Study funded by NASA's Ocean Biology and Biogeochemistry Program that aims to improve understanding and prediction of land-ocean interactions in a rapidly changing Arctic coastal zone, and assess vulnerability, response, feedbacks and resilience of coastal ecosystems, communities and natural resources to current and future pressures. Specific science objectives include: - Quantify lateral fluxes to the arctic inner shelf from (i) rivers and (ii) the outer shelf/basin that affect biology, biodiversity, biogeochemistry (i.e. organic matter, nutrients, suspended sediment), and the processing rates of these constituents in coastal waters. - Evaluate the impact of the thawing of Arctic permafrost within the river basins on coastal biology, biodiversity and biogeochemistry, including various rates of community production and the role these may play in the health of regional economies. - Assess the impact of changing Arctic landfast ice and coastal sea ice dynamics. - Establish a baseline for comparison to future change, and use state-of-the-art models to assess impacts of environmental change on coastal biology, biodiversity and biogeochemistry. A key component of Arctic-COLORS will be the integration of satellite and field observations with coupled physical-biogeochemical models for predicting impacts of future pressures on Arctic, coastal ocean, biological processes and biogeochemical cycles. Through interagency and international collaborations, and through the organization of dedicated workshops, town hall meetings and presentations at international conferences, the scoping study engages the broader scientific community and invites participation of

  1. An Arctic Ice/Ocean Coupled Model with Wave Interactions

    Science.gov (United States)

    2015-09-30

    discussed by DRI participants may aid our understanding as well, e.g. those conducted in the Hamburg Ship Model Basin. Our theoretical advances benefit...the project are – continued modifications to the Arctic wide WIM code in association with advances relating to a new ice/ocean model known as... Auckland , December 2014. Montiel, F. Transmission of ocean waves through a row of randomly perturbed circular ice floes. Minisymposium on Wave Motions of

  2. Response of halocarbons to ocean acidification in the Arctic

    NARCIS (Netherlands)

    Hopkins, F.E.; Kimmance, S.A.; Stephens, J.A.; Bellerby, R.G.J.; Brussaard, C.P.D.; Czerny, J.; Schulz, K.G.; Archer, S.D.

    2013-01-01

    The potential effect of ocean acidification (OA) on seawater halocarbons in the Arctic was investigated during a mesocosm experiment in Spitsbergen in June-July 2010. Over a period of 5 weeks, natural phytoplankton communities in nine similar to 50 m(3) mesocosms were studied under a range of pCO(2)

  3. Response of halocarbons to ocean acidification in the Arctic

    NARCIS (Netherlands)

    Hopkins, F.E.; Kimmance, S.A.; Stephens, J.A.; Bellerby, R.G.J.; Brussaard, C.P.D.; Czerny, J.; Schulz, K.G.; Archer, S.D.

    2013-01-01

    The potential effect of ocean acidification (OA) on seawater halocarbons in the Arctic was investigated during a mesocosm experiment in Spitsbergen in June-July 2010. Over a period of 5 weeks, natural phytoplankton communities in nine ~ 50 m3 mesocosms were studied under a range of pCO2 treatments

  4. Acquiring Marine Data in the Canada Basin, Arctic Ocean

    Science.gov (United States)

    Hutchinson, Deborah R.; Jackson, H. Ruth; Shimeld, John W.; Chapman, C. Borden; Childs, Jonathan R.; Funck, Thomas; Rowland, Robert W.

    2009-06-01

    Despite the record minimum ice extent in the Arctic Ocean for the past 2 years, collecting geophysical data with towed sensors in ice-covered regions continues to pose enormous challenges. Significant parts of the Canada Basin in the western Arctic Ocean have remained largely unmapped because thick multiyear ice has limited access even by research vessels strengthened against ice [Jackson et al., 1990]. Because of the resulting paucity of data, the western Arctic Ocean is one of the few areas of ocean in the world where major controversies still exist with respect to its origin and tectonic evolution [Grantz et al., 1990; Lawver and Scotese, 1990; Lane, 1997; Miller et al., 2006]. This article describes the logistical challenges and initial data sets from geophysical seismic reflection, seismic refraction, and hydrographic surveys in the Canada Basin conducted by scientists with U.S. and Canadian government agencies (Figure 1a) to fulfill the requirements of the United Nations Convention on the Law of the Sea to determine sediment thickness, geological origin, and basin evolution in this unexplored part of the world. Some of these data were collected using a single ship, but the heaviest ice conditions necessitated using two icebreakers, similar to other recent Arctic surveys [e.g., Jokat, 2003].

  5. Petroleum prospectivity of the Canada Basin, Arctic Ocean

    Science.gov (United States)

    Grantz, Arthur; Hart, Patrick E.

    2012-01-01

    Reconnaissance seismic reflection data indicate that Canada Basin is a >700,000 sq. km. remnant of the Amerasia Basin of the Arctic Ocean that lies south of the Alpha-Mendeleev Large Igneous Province, which was constructed across the northern part of the Amerasia Basin between about 127 and 89-83.5 Ma. Canada Basin was filled by Early Jurassic to Holocene detritus from the Beaufort-Mackenzie Deltaic System, which drains the northern third of interior North America, with sizable contributions from Alaska and Northwest Canada. The basin contains roughly 5 or 6 million cubic km of sediment. Three fourths or more of this volume generates low amplitude seismic reflections, interpreted to represent hemipelagic deposits, which contain lenses to extensive interbeds of moderate amplitude reflections interpreted to represent unconfined turbidite and amalgamated channel deposits.Extrapolation from Arctic Alaska and Northwest Canada suggests that three fourths of the section in Canada Basin is correlative with stratigraphic sequences in these areas that contain intervals of hydrocarbon source rocks. In addition, worldwide heat flow averages suggest that about two thirds of Canada Basin lies in the oil or gas windows. Structural, stratigraphic and combined structural and stratigraphic features of local to regional occurrence offer exploration targets in Canada Basin, and at least one of these contains bright spots. However, deep water (to almost 4000 m), remoteness from harbors and markets, and thick accumulations of seasonal to permanent sea ice (until its possible removal by global warming later this century) will require the discovery of very large deposits for commercial success in most parts of Canada Basin. ?? 2011 Elsevier Ltd.

  6. NODC Standard Product: International ocean atlas Volume 2 - Biological atlas of the Arctic Seas 2000 - Plankton of the Barents and Kara Seas (1 disc set) (NODC Accession 0098568)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Presented in this CD-ROM are physical and biological data for the region extending from the Barents Sea to the Kara Sea during 158 scientific cruises for the period...

  7. Impact of North Atlantic Current changes on the Nordic Seas and the Arctic Ocean

    OpenAIRE

    Kauker, Frank; Gerdes, Rüdiger; Karcher, Michael; Köberle, Cornelia

    2005-01-01

    The impact of North Atlantic Current (NAC) volume, heat, and salt transport variability onto the NordicSeas and the Arctic Ocean is investigated using numerical hindcast and sensitivity experiments. Theocean-sea ice model reproduces observed propagation pathways and speeds of SST anomalies.Part of the signal reaching the entrance to the Nordic Seas between Iceland and Scotland originatesin the lower latitude North Atlantic. Response experiments with different prescribed conditionsat 50N show ...

  8. Pan-Arctic distributions of continental runoff in the Arctic Ocean.

    Science.gov (United States)

    Fichot, Cédric G; Kaiser, Karl; Hooker, Stanford B; Amon, Rainer M W; Babin, Marcel; Bélanger, Simon; Walker, Sally A; Benner, Ronald

    2013-01-01

    Continental runoff is a major source of freshwater, nutrients and terrigenous material to the Arctic Ocean. As such, it influences water column stratification, light attenuation, surface heating, gas exchange, biological productivity and carbon sequestration. Increasing river discharge and thawing permafrost suggest that the impacts of continental runoff on these processes are changing. Here, a new optical proxy was developed and implemented with remote sensing to determine the first pan-Arctic distribution of terrigenous dissolved organic matter (tDOM) and continental runoff in the surface Arctic Ocean. Retrospective analyses revealed connections between the routing of North American runoff and the recent freshening of the Canada Basin, and indicated a correspondence between climate-driven changes in river discharge and tDOM inventories in the Kara Sea. By facilitating the real-time, synoptic monitoring of tDOM and freshwater runoff in surface polar waters, this novel approach will help understand the manifestations of climate change in this remote region.

  9. Arctic Ocean surface geostrophic circulation 2003–2014

    Directory of Open Access Journals (Sweden)

    T. W. K. Armitage

    2017-07-01

    Full Text Available Monitoring the surface circulation of the ice-covered Arctic Ocean is generally limited in space, time or both. We present a new 12-year record of geostrophic currents at monthly resolution in the ice-covered and ice-free Arctic Ocean derived from satellite radar altimetry and characterise their seasonal to decadal variability from 2003 to 2014, a period of rapid environmental change in the Arctic. Geostrophic currents around the Arctic basin increased in the late 2000s, with the largest increases observed in summer. Currents in the southeastern Beaufort Gyre accelerated in late 2007 with higher current speeds sustained until 2011, after which they decreased to speeds representative of the period 2003–2006. The strength of the northwestward current in the southwest Beaufort Gyre more than doubled between 2003 and 2014. This pattern of changing currents is linked to shifting of the gyre circulation to the northwest during the time period. The Beaufort Gyre circulation and Fram Strait current are strongest in winter, modulated by the seasonal strength of the atmospheric circulation. We find high eddy kinetic energy (EKE congruent with features of the seafloor bathymetry that are greater in winter than summer, and estimates of EKE and eddy diffusivity in the Beaufort Sea are consistent with those predicted from theoretical considerations. The variability of Arctic Ocean geostrophic circulation highlights the interplay between seasonally variable atmospheric forcing and ice conditions, on a backdrop of long-term changes to the Arctic sea ice–ocean system. Studies point to various mechanisms influencing the observed increase in Arctic Ocean surface stress, and hence geostrophic currents, in the 2000s – e.g. decreased ice concentration/thickness, changing atmospheric forcing, changing ice pack morphology; however, more work is needed to refine the representation of atmosphere–ice–ocean coupling in models before we can fully

  10. Bromine measurements in ozone depleted air over the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    J. A. Neuman

    2010-07-01

    Full Text Available In situ measurements of ozone, photochemically active bromine compounds, and other trace gases over the Arctic Ocean in April 2008 are used to examine the chemistry and geographical extent of ozone depletion in the arctic marine boundary layer (MBL. Data were obtained from the NOAA WP-3D aircraft during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC study and the NASA DC-8 aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS study. Fast (1 s and sensitive (detection limits at the low pptv level measurements of BrCl and BrO were obtained from three different chemical ionization mass spectrometer (CIMS instruments, and soluble bromide was measured with a mist chamber. The CIMS instruments also detected Br2. Subsequent laboratory studies showed that HOBr rapidly converts to Br2 on the Teflon instrument inlets. This detected Br2 is identified as active bromine and represents a lower limit of the sum HOBr + Br2. The measured active bromine is shown to likely be HOBr during daytime flights in the arctic. In the MBL over the Arctic Ocean, soluble bromide and active bromine were consistently elevated and ozone was depleted. Ozone depletion and active bromine enhancement were confined to the MBL that was capped by a temperature inversion at 200–500 m altitude. In ozone-depleted air, BrO rarely exceeded 10 pptv and was always substantially lower than soluble bromide that was as high as 40 pptv. BrCl was rarely enhanced above the 2 pptv detection limit, either in the MBL, over Alaska, or in the arctic free troposphere.

  11. Dissolved iron in the Arctic Ocean : Important role of hydrothermal sources, shelf input and scavenging removal

    NARCIS (Netherlands)

    Klunder, M. B.; Laan, P.; Middag, R.; de Baar, H. J. W.; Bakker, K.

    2012-01-01

    Arctic Ocean waters exchange with the North Atlantic, and thus dissolved iron (DFe) in the Arctic has implications for the global Fe cycle. We present deep water (>250 m) DFe concentrations of the Central Arctic Ocean (Nansen, Amundsen and Makarov Basins). The DFe concentration in the deep waters

  12. An inventory of Arctic Ocean data in the World Ocean Database

    Science.gov (United States)

    Zweng, Melissa M.; Boyer, Tim P.; Baranova, Olga K.; Reagan, James R.; Seidov, Dan; Smolyar, Igor V.

    2018-03-01

    The World Ocean Database (WOD) contains over 1.3 million oceanographic casts (where cast refers to an oceanographic profile or set of profiles collected concurrently at more than one depth between the ocean surface and ocean bottom) collected in the Arctic Ocean basin and its surrounding marginal seas. The data, collected from 1849 to the present, come from many submitters and countries, and were collected using a variety of instruments and platforms. These data, along with the derived products World Ocean Atlas (WOA) and the Arctic Regional Climatologies, are exceptionally useful - the data are presented in a standardized, easy to use format and include metadata and quality control information. Collecting data in the Arctic Ocean is challenging, and coverage in space and time ranges from excellent to nearly non-existent. WOD continues to compile a comprehensive collection of Arctic Ocean profile data, ideal for oceanographic, environmental and climatic analyses (https://doi.org/10.7289/V54Q7S16" target="_blank">https://doi.org/10.7289/V54Q7S16).

  13. A new high resolution tidal model in the arctic ocean

    DEFF Research Database (Denmark)

    Cancet, M.; Andersen, Ole Baltazar; Lyard, F.

    The Arctic Ocean is a challenging region for tidal modeling, because of its complex and not well-documented bathymetry, together combined with the intermittent presence of sea ice and the fact that the in situ tidal observations are rather scarce at such high latitudes. As a consequence, the accu......The Arctic Ocean is a challenging region for tidal modeling, because of its complex and not well-documented bathymetry, together combined with the intermittent presence of sea ice and the fact that the in situ tidal observations are rather scarce at such high latitudes. As a consequence......, the accuracy of the global tidal models decreases by several centimeters in the Polar Regions. In particular, it has a large impact on the quality of the satellite altimeter sea surface heights in these regions (ERS1/2, Envisat, CryoSat-2, SARAL/AltiKa and the future Sentinel-3 mission). Better knowledge......-growing maritime and industrial activities in this region. NOVELTIS and DTU Space have developed a regional, high-resolution tidal atlas in the Arctic Ocean, in the framework of the CryoSat Plus for Ocean (CP4O) ESA project. In particular, this atlas benefits from the assimilation of the most complete satellite...

  14. Preliminary Geospatial Analysis of Arctic Ocean Hydrocarbon Resources

    Energy Technology Data Exchange (ETDEWEB)

    Long, Philip E.; Wurstner, Signe K.; Sullivan, E. C.; Schaef, Herbert T.; Bradley, Donald J.

    2008-10-01

    Ice coverage of the Arctic Ocean is predicted to become thinner and to cover less area with time. The combination of more ice-free waters for exploration and navigation, along with increasing demand for hydrocarbons and improvements in technologies for the discovery and exploitation of new hydrocarbon resources have focused attention on the hydrocarbon potential of the Arctic Basin and its margins. The purpose of this document is to 1) summarize results of a review of published hydrocarbon resources in the Arctic, including both conventional oil and gas and methane hydrates and 2) develop a set of digital maps of the hydrocarbon potential of the Arctic Ocean. These maps can be combined with predictions of ice-free areas to enable estimates of the likely regions and sequence of hydrocarbon production development in the Arctic. In this report, conventional oil and gas resources are explicitly linked with potential gas hydrate resources. This has not been attempted previously and is particularly powerful as the likelihood of gas production from marine gas hydrates increases. Available or planned infrastructure, such as pipelines, combined with the geospatial distribution of hydrocarbons is a very strong determinant of the temporal-spatial development of Arctic hydrocarbon resources. Significant unknowns decrease the certainty of predictions for development of hydrocarbon resources. These include: 1) Areas in the Russian Arctic that are poorly mapped, 2) Disputed ownership: primarily the Lomonosov Ridge, 3) Lack of detailed information on gas hydrate distribution, and 4) Technical risk associated with the ability to extract methane gas from gas hydrates. Logistics may control areas of exploration more than hydrocarbon potential. Accessibility, established ownership, and leasing of exploration blocks may trump quality of source rock, reservoir, and size of target. With this in mind, the main areas that are likely to be explored first are the Bering Strait and Chukchi

  15. Storm-Driven Mixing and Potential Impact on the Arctic Ocean

    National Research Council Canada - National Science Library

    Yang, Jiayan

    2004-01-01

    Observations of the ocean, atmosphere, and ice made by Ice-Ocean Environmental Buoys indicate that mixing events reaching the depth of the halocline have occurred in various regions in the Arctic Ocean...

  16. Climate Change and China as a Global Emerging Regulatory Sea Power in the Arctic Ocean

    DEFF Research Database (Denmark)

    Cassotta Pertoldi-Bianchi, Sandra; Hossain, Kamrul; Ren, Jingzheng

    2015-01-01

    The impact of climate change in the Arctic Ocean such as ice melting and ice retreat facilitates natural resources extraction. Arctic fossil fuel becomes the drivers of geopolitical changes in the Arctic Ocean. Climate change facilitates natural resource extractions and increases competition...... on the Law of the Sea (UNCLOS) and the Arctic Council (AC) are taken into consideration under climate change effects, to assess how global legal frameworks and institutions can deal with China’s strategy in the Arctic Ocean. China’s is moving away from its role as “humble power” to one of “informal...... imperialistic” resulting in substantial impact on the Arctic and Antartic dynamism. Due to ice-melting, an easy access to natural resources, China’s Arctic strategy in the Arctic Ocean has reinforced its military martitime strategy and has profoundly changed its maritime military doctrine shifting from regional...

  17. Arctic Sea Ice Basal Melt Onset Variability and Associated Ocean Surface Heating

    Science.gov (United States)

    Merrick, R. A.; Hutchings, J. K.

    2015-12-01

    The interannual and regional variability in Arctic sea ice melt has previously been characterized only in terms of surface melting. A focus on the variability in the onset of basal melt is additionally required to understand Arctic melt patterns. Monitoring basal melt provides a glimpse into the importance of ocean heating to sea ice melt. This warming is predominantly through seawater exposure due to lead opening and the associated solar warming at the ocean's surface. We present the temporal variability in basal melt onset observed by ice mass balance buoys throughout the Arctic Ocean since 2003, providing a different perspective than the satellite microwave data used to measure the onset of surface melt. We found that melt onset varies greatly, even for buoys deployed within 100km of each other. Therefore large volumes of data are necessary to accurately estimate the variability of basal melt onset. Once the variability of basal melt onset has been identified, we can investigate how this range has been changing as a response to atmospheric and oceanic warming, changes in ice morphology as well as the intensification of the ice albedo feedback.

  18. Arctic black shale formation during Cretaceous Oceanic Anoxic Event 2

    DEFF Research Database (Denmark)

    Lenniger, Marc; Nøhr-Hansen, Henrik; Hills, Len V.

    2014-01-01

    The Late Cretaceous Oceanic Anoxic Event 2 (OAE2) represents a major perturbation of the global carbon cycle caused by the widespread deposition of organic-rich black shales. Although the paleoceanographic response and the spatial extent of bottom-water anoxia in low and mid-paleolatitudes are re......The Late Cretaceous Oceanic Anoxic Event 2 (OAE2) represents a major perturbation of the global carbon cycle caused by the widespread deposition of organic-rich black shales. Although the paleoceanographic response and the spatial extent of bottom-water anoxia in low and mid...... caused massive organic-carbon burial on the Arctic shelf in general, with important implications for hydrocarbon source-rock distribution in the Arctic region....

  19. Trends in Arctic Sea Ice Volume 2010-2013 from CryoSat-2

    Science.gov (United States)

    Tilling, R.; Ridout, A.; Wingham, D.; Shepherd, A.; Haas, C.; Farrell, S. L.; Schweiger, A. J.; Zhang, J.; Giles, K.; Laxon, S.

    2013-12-01

    Satellite records show a decline in Arctic sea ice extent over the past three decades with a record minimum in September 2012, and results from the Pan-Arctic Ice-Ocean Modelling and Assimilation System (PIOMAS) suggest that this has been accompanied by a reduction in volume. We use three years of measurements recorded by the European Space Agency CryoSat-2 (CS-2) mission, validated with in situ data, to generate estimates of seasonal variations and inter-annual trends in Arctic sea ice volume between 2010 and 2013. The CS-2 estimates of sea ice thickness agree with in situ estimates derived from upward looking sonar measurements of ice draught and airborne measurements of ice thickness and freeboard to within 0.1 metres. Prior to the record minimum in summer 2012, autumn and winter Arctic sea ice volume had fallen by ~1300 km3 relative to the previous year. Using the full 3-year period of CS-2 observations, we estimate that winter Arctic sea ice volume has decreased by ~700 km3/yr since 2010, approximately twice the average rate since 1980 as predicted by the PIOMAS.

  20. Arctic deep-water ferromanganese-oxide deposits reflect the unique characteristics of the Arctic Ocean

    Science.gov (United States)

    Hein, James; Konstantinova, Natalia; Mikesell, Mariah; Mizell, Kira; Fitzsimmons, Jessica N.; Lam, Phoebe; Jensen, Laramie T.; Xiang, Yang; Gartman, Amy; Cherkashov, Georgy; Hutchinson, Deborah; Till, Claire P.

    2017-01-01

    Little is known about marine mineral deposits in the Arctic Ocean, an ocean dominated by continental shelf and basins semi-closed to deep-water circulation. Here, we present data for ferromanganese crusts and nodules collected from the Amerasia Arctic Ocean in 2008, 2009, and 2012 (HLY0805, HLY0905, HLY1202). We determined mineral and chemical compositions of the crusts and nodules and the onset of their formation. Water column samples from the GEOTRACES program were analyzed for dissolved and particulate scandium concentrations, an element uniquely enriched in these deposits.The Arctic crusts and nodules are characterized by unique mineral and chemical compositions with atypically high growth rates, detrital contents, Fe/Mn ratios, and low Si/Al ratios, compared to deposits found elsewhere. High detritus reflects erosion of submarine outcrops and North America and Siberia cratons, transport by rivers and glaciers to the sea, and distribution by sea ice, brines, and currents. Uniquely high Fe/Mn ratios are attributed to expansive continental shelves, where diagenetic cycling releases Fe to bottom waters, and density flows transport shelf bottom water to the open Arctic Ocean. Low Mn contents reflect the lack of a mid-water oxygen minimum zone that would act as a reservoir for dissolved Mn. The potential host phases and sources for elements with uniquely high contents are discussed with an emphasis on scandium. Scandium sorption onto Fe oxyhydroxides and Sc-rich detritus account for atypically high scandium contents. The opening of Fram Strait in the Miocene and ventilation of the deep basins initiated Fe-Mn crust growth ∼15 Myr ago.

  1. Initial opening of the Eurasian Basin, Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Kai Berglar

    2016-10-01

    Full Text Available Analysis of the transition from the NE Yermak Plateau into the oceanic Eurasian Basin sheds light on the Paleocene formation of this Arctic basin. Newly acquired multichannel seismic data with a 3600 m long streamer shot during ice-free conditions enables the interpretation of crustal structures. Evidence is provided that no major compressional deformation affected the NE Yermak Plateau. The seismic data reveal that the margin is around 80 km wide and consists of rotated fault blocks, major listric normal faults, and half-grabens filled with syn-rift sediments. Taking into account published magnetic and gravimetric data, this setting is interpreted as a rifted continental margin, implying that the NE Yermak Plateau is of continental origin. The transition from the Yermak Plateau to the oceanic Eurasian Basin might be located at a prominent basement high, probably formed by exhumed mantle. In contrast to the Yermak Plateau margin, the North Barents Sea continental margin shows a steep continental slope with a relatively abrupt transition to the oceanic domain. Based on one composite seismic line, it is speculated that the initial opening direction of the Eurasian Basin in the Arctic Ocean was highly oblique to the present day seafloor spreading direction.

  2. Orbital-scale Central Arctic Ocean Temperature Records from Benthic Foraminiferal δ18O and Ostracode Mg/Ca Ratios

    Science.gov (United States)

    Keller, K.; Cronin, T. M.; Dwyer, G. S.; Farmer, J. R.; Poirier, R. K.; Schaller, M. F.

    2017-12-01

    Orbital-scale climate variability is often amplified in the polar region, for example in changes in seawater temperature, sea-ice cover, deep-water formation, ecosystems, heat storage and carbon cycling. Yet, the relationship between the Arctic Ocean and global climate remains poorly understood due largely to limited orbital-scale paleoclimate records, the complicated nature of sea-ice response to climate and limited abundance of deep sea biological proxies. Here we reconstruct central Arctic Ocean bottom temperatures over the last 600 kyr using ostracode Mg/Ca ratios (genus Krithe) and benthic foraminiferal oxygen isotope ratios (δ18Obf - I. teretis, O. tener, P. bulloides, C. reniforme, C. wuellerstorfi) in six sediment cores recovered from the Mendeleev and Northwind Ridges (700- 2726 m water depth). We examined glacial-interglacial cycles in Arctic seawater temperatures and Arctic δ18Obf chronostratigraphy to reconcile effects of changing bottom water temperature, ice volume and regional hydrography on δ18Obf records. Results show lower ( 10-12 mmol/mol) interglacial and higher ( 16-23 mmol/mol) glacial Mg/Ca ratios, signifying intermediate depth ocean warming during glacials of up to 2 ºC. These temperature maxima are likely related to a deepening of the halocline and the corresponding deeper influence of warm Atlantic water. Glacial-interglacial δ18Obf ranges are smaller in the Arctic ( 0.8-1‰ VPDB) than in the global ocean ( 1.8 ‰). However, when the distinct glacial-interglacial temperature histories of the Arctic (glacial warming) and global ocean (glacial cooling) are accounted for, both Arctic and global ocean seawater δ18O values (δ18Osw) exhibit similar 1.2-1.3 ‰ glacial-interglacial ranges. Thus, Arctic δ18Obf confirms glacial Arctic warming inferred from ostracode Mg/Ca. This study will discuss the strengths and limitations of applying paired Mg/Ca and oxygen isotope proxies in reconstructing more robust paleoceanographic changes in the

  3. Processes of multibathyal aragonite undersaturation in the Arctic Ocean

    Science.gov (United States)

    Wynn, J. G.; Robbins, L. L.; Anderson, L. G.

    2016-11-01

    During 3 years of study (2010-2012), the western Arctic Ocean was found to have unique aragonite saturation profiles with up to three distinct aragonite undersaturation zones. This complexity is produced as inflow of Atlantic-derived and Pacific-derived water masses mix with Arctic-derived waters, which are further modified by physiochemical and biological processes. The shallowest aragonite undersaturation zone, from the surface to ˜30 m depth is characterized by relatively low alkalinity and other dissolved ions. Besides local influence of biological processes on aragonite undersaturation of shallow coastal waters, the nature of this zone is consistent with dilution by sea-ice melt and invasion of anthropogenic CO2 from the atmosphere. A second undersaturated zone at ˜90-220 m depth (salinity ˜31.8-35.4) occurs within the Arctic Halocline and is characterized by elevated pCO2 and nutrients. The nature of this horizon is consistent with remineralization of organic matter on shallow continental shelves bordering the Canada Basin and the input of the nutrients and CO2 entrained by currents from the Pacific Inlet. Finally, the deepest aragonite undersaturation zone is at greater than 2000 m depth and is controlled by similar processes as deep aragonite saturation horizons in the Atlantic and Pacific Oceans. The comparatively shallow depth of this deepest aragonite saturation horizon in the Arctic is maintained by relatively low temperatures, and stable chemical composition. Understanding the mechanisms controlling the distribution of these aragonite undersaturation zones, and the time scales over which they operate will be crucial to refine predictive models.

  4. Processes of multibathyal aragonite undersaturation in the Arctic Ocean

    Science.gov (United States)

    Wynn, J.G.; Robbins, L.L.; Anderson, L.G.

    2016-01-01

    During 3 years of study (2010–2012), the western Arctic Ocean was found to have unique aragonite saturation profiles with up to three distinct aragonite undersaturation zones. This complexity is produced as inflow of Atlantic-derived and Pacific-derived water masses mix with Arctic-derived waters, which are further modified by physiochemical and biological processes. The shallowest aragonite undersaturation zone, from the surface to ∼30 m depth is characterized by relatively low alkalinity and other dissolved ions. Besides local influence of biological processes on aragonite undersaturation of shallow coastal waters, the nature of this zone is consistent with dilution by sea-ice melt and invasion of anthropogenic CO2 from the atmosphere. A second undersaturated zone at ∼90–220 m depth (salinity ∼31.8–35.4) occurs within the Arctic Halocline and is characterized by elevated pCO2 and nutrients. The nature of this horizon is consistent with remineralization of organic matter on shallow continental shelves bordering the Canada Basin and the input of the nutrients and CO2 entrained by currents from the Pacific Inlet. Finally, the deepest aragonite undersaturation zone is at greater than 2000 m depth and is controlled by similar processes as deep aragonite saturation horizons in the Atlantic and Pacific Oceans. The comparatively shallow depth of this deepest aragonite saturation horizon in the Arctic is maintained by relatively low temperatures, and stable chemical composition. Understanding the mechanisms controlling the distribution of these aragonite undersaturation zones, and the time scales over which they operate will be crucial to refine predictive models.

  5. Latitudinal variation of phytoplankton communities in the western Arctic Ocean

    Science.gov (United States)

    Min Joo, Hyoung; Lee, Sang H.; Won Jung, Seung; Dahms, Hans-Uwe; Hwan Lee, Jin

    2012-12-01

    Recent studies have shown that photosynthetic eukaryotes are an active and often dominant component of Arctic phytoplankton assemblages. In order to explore this notion at a large scale, samples were collected to investigate the community structure and biovolume of phytoplankton along a transect in the western Arctic Ocean. The transect included 37 stations at the surface and subsurface chlorophyll a maximum (SCM) depths in the Bering Sea, Chukchi Sea, and Canadian Basin from July 19 to September 5, 2008. Phytoplankton (>2 μm) were identified and counted. A cluster analysis of abundance and biovolume data revealed different assemblages over the shelf, slope, and basin regions. Phytoplankton communities were composed of 71 taxa representing Dinophyceae, Cryptophyceae, Bacillariophyceae, Chrysophyceae, Dictyochophyceae, Prasinophyceae, and Prymnesiophyceae. The most abundant species were of pico- to nano-size at the surface and SCM depths at most stations. Nano- and pico-sized phytoplankton appeared to be dominant in the Bering Sea, whereas diatoms and nano-sized plankton provided the majority of taxon diversity in the Bering Strait and in the Chukchi Sea. From the western Bering Sea to the Bering Strait, the abundance, biovolume, and species diversity of phytoplankton provided a marked latitudinal gradient towards the central Arctic. Although pico- and nano-sized phytoplankton contributed most to cell abundance, their chlorophyll a contents and biovolumes were less than those of the larger micro-sized taxa. Micro-sized phytoplankton contributed most to the biovolume in the largely ice-free waters of the western Arctic Ocean during summer 2008.

  6. Decorrelation scales for Arctic Ocean hydrography - Part I: Amerasian Basin

    Science.gov (United States)

    Sumata, Hiroshi; Kauker, Frank; Karcher, Michael; Rabe, Benjamin; Timmermans, Mary-Louise; Behrendt, Axel; Gerdes, Rüdiger; Schauer, Ursula; Shimada, Koji; Cho, Kyoung-Ho; Kikuchi, Takashi

    2018-03-01

    Any use of observational data for data assimilation requires adequate information of their representativeness in space and time. This is particularly important for sparse, non-synoptic data, which comprise the bulk of oceanic in situ observations in the Arctic. To quantify spatial and temporal scales of temperature and salinity variations, we estimate the autocorrelation function and associated decorrelation scales for the Amerasian Basin of the Arctic Ocean. For this purpose, we compile historical measurements from 1980 to 2015. Assuming spatial and temporal homogeneity of the decorrelation scale in the basin interior (abyssal plain area), we calculate autocorrelations as a function of spatial distance and temporal lag. The examination of the functional form of autocorrelation in each depth range reveals that the autocorrelation is well described by a Gaussian function in space and time. We derive decorrelation scales of 150-200 km in space and 100-300 days in time. These scales are directly applicable to quantify the representation error, which is essential for use of ocean in situ measurements in data assimilation. We also describe how the estimated autocorrelation function and decorrelation scale should be applied for cost function calculation in a data assimilation system.

  7. BAROMETRIC PRESSURE and Other Data From Arctic Ocean from 19771114 to 19890517 (NODC Accession 9200249)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data in this accession is from the CD-Rom containing data from eastern Arctic collected as part of Global Ocean Data Archeaology and Rescue (GODAR) project...

  8. First evaluation of MyOcean altimetric data in the Arctic Ocean

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Andersen, Ole Baltazar; Knudsen, Per

    2012-01-01

    The MyOcean V2 preliminary (V2p) data set of weekly gridded sea level anomaly (SLA) maps from 1993 to 2009 over the Arctic region is evaluated against existing altimetric data sets and tide gauge data. Compared with DUACS V3.0.0 (Data Unification and Altimeter Combination System) data set, MyOcean...... V2p data set improves spatial coverage and quality as well as maximum temporal correlation coefficient between altimetry and tide gauge data. The estimated amplitude of sea level annual signal and linear sea level trend from MyOcean data set are evaluated against altimetry from DUACS and RADS (Radar...... Altimeter Database System), the SODA (Simple Ocean Data Assimilation) ocean reanalysis and tide gauge data sets from PSMSL (Permanent Service for Mean Sea Level). The results show that the MyOcean data set fits in-situ measurements better than DUACS data set with respect to amplitude of annual signal...

  9. The emergence of modern sea ice cover in the Arctic Ocean.

    Science.gov (United States)

    Knies, Jochen; Cabedo-Sanz, Patricia; Belt, Simon T; Baranwal, Soma; Fietz, Susanne; Rosell-Melé, Antoni

    2014-11-28

    Arctic sea ice coverage is shrinking in response to global climate change and summer ice-free conditions in the Arctic Ocean are predicted by the end of the century. The validity of this prediction could potentially be tested through the reconstruction of the climate of the Pliocene epoch (5.33-2.58 million years ago), an analogue of a future warmer Earth. Here we show that, in the Eurasian sector of the Arctic Ocean, ice-free conditions prevailed in the early Pliocene until sea ice expanded from the central Arctic Ocean for the first time ca. 4 million years ago. Amplified by a rise in topography in several regions of the Arctic and enhanced freshening of the Arctic Ocean, sea ice expanded progressively in response to positive ice-albedo feedback mechanisms. Sea ice reached its modern winter maximum extension for the first time during the culmination of the Northern Hemisphere glaciation, ca. 2.6 million years ago.

  10. Contrasting physiological responses to future ocean acidification among Arctic copepod populations

    DEFF Research Database (Denmark)

    Thor, Peter; Bailey, Allison; Dupont, Sam

    2018-01-01

    Widespread ocean acidification (OA) is modifying the chemistry of the global ocean, and the Arctic is recognised as the region where the changes will progress at the fastest rate. Moreover, Arctic species show lower capacity for cellular homeostasis and acid-base regulation rendering them...

  11. The Arctic Ocean marine carbon cycle: evaluation of air-sea CO2 exchanges, ocean acidification impacts and potential feedbacks

    Directory of Open Access Journals (Sweden)

    N. R. Bates

    2009-11-01

    Full Text Available At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2 on the order of −66 to −199 Tg C year−1 (1012 g C, contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean has an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic Ocean surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3 mineral saturation states (Ω of seawater while seasonal phytoplankton primary production (PP mitigates this effect. Biological amplification of ocean acidification effects in subsurface waters, due to the remineralization of organic matter, is likely to reduce the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems

  12. Giant caldera in the Arctic Ocean: Evidence of the catastrophic eruptive event.

    Science.gov (United States)

    Piskarev, Alexey; Elkina, Daria

    2017-04-10

    A giant caldera located in the eastern segment of the Gakkel Ridge could be firstly seen on the bathymetric map of the Arctic Ocean published in 1999. In 2014, seismic and multibeam echosounding data were acquired at the location. The caldera is 80 km long, 40 km wide and 1.2 km deep. The total volume of ejected volcanic material is estimated as no less than 3000 km 3 placing it into the same category with the largest Quaternary calderas (Yellowstone and Toba). Time of the eruption is estimated as ~1.1 Ma. Thin layers of the volcanic material related to the eruption had been identified in sedimentary cores located about 1000 km away from the Gakkel Ridge. The Gakkel Ridge Caldera is the single example of a supervolcano in the rift zone of the Mid-Oceanic Ridge System.

  13. Meteorological conditions in the central Arctic summer during the Arctic Summer Cloud Ocean Study (ASCOS

    Directory of Open Access Journals (Sweden)

    M. Tjernström

    2012-08-01

    Full Text Available Understanding the rapidly changing climate in the Arctic is limited by a lack of understanding of underlying strong feedback mechanisms that are specific to the Arctic. Progress in this field can only be obtained by process-level observations; this is the motivation for intensive ice-breaker-based campaigns such as the Arctic Summer Cloud-Ocean Study (ASCOS, described here. However, detailed field observations also have to be put in the context of the larger-scale meteorology, and short field campaigns have to be analysed within the context of the underlying climate state and temporal anomalies from this.

    To aid in the analysis of other parameters or processes observed during this campaign, this paper provides an overview of the synoptic-scale meteorology and its climatic anomaly during the ASCOS field deployment. It also provides a statistical analysis of key features during the campaign, such as key meteorological variables, the vertical structure of the lower troposphere and clouds, and energy fluxes at the surface. In order to assess the representativity of the ASCOS results, we also compare these features to similar observations obtained during three earlier summer experiments in the Arctic Ocean: the AOE-96, SHEBA and AOE-2001 expeditions.

    We find that these expeditions share many key features of the summertime lower troposphere. Taking ASCOS and the previous expeditions together, a common picture emerges with a large amount of low-level cloud in a well-mixed shallow boundary layer, capped by a weak to moderately strong inversion where moisture, and sometimes also cloud top, penetrate into the lower parts of the inversion. Much of the boundary-layer mixing is due to cloud-top cooling and subsequent buoyant overturning of the cloud. The cloud layer may, or may not, be connected with surface processes depending on the depths of the cloud and surface-based boundary layers and on the relative strengths of surface-shear and

  14. Future scientific drilling in the Arctic Ocean: Key objectives, areas, and strategies

    Science.gov (United States)

    Stein, R.; Coakley, B.; Mikkelsen, N.; O'Regan, M.; Ruppel, C.

    2012-04-01

    In spite of the critical role of the Arctic Ocean in climate evolution, our understanding of the short- and long-term paleoceanographic and paleoclimatic history through late Mesozoic-Cenozoic times, as well as its plate-tectonic evolution, remains behind that from the other world's oceans. This lack of knowledge is mainly caused by the major technological/logistic problems in reaching this permanently ice-covered region with normal research vessels and in retrieving long and undisturbed sediment cores. With the Arctic Coring Expedition - ACEX (or IODP Expedition 302), the first Mission Specific Platform (MSP) expedition within IODP, a new era in Arctic research began (Backman, Moran, Mayer, McInroy et al., 2006). ACEX proved that, with an intensive ice-management strategy, successful scientific drilling in the permanently ice-covered central Arctic Ocean is possible. ACEX is certainly a milestone in Arctic Ocean research, but - of course - further drilling activities are needed in this poorly studied ocean. Furthermore, despite the success of ACEX fundamental questions related to the long- and short-term climate history of the Arctic Ocean during Mesozoic-Cenozoic times remain unanswered. This is partly due to poor core recovery during ACEX and, especially, because of a major mid-Cenozoic hiatus in this single record. Since ACEX, a series of workshops were held to develop a scientific drilling strategy for investigating the tectonic and paleoceanographic history of the Arctic Ocean and its role in influencing the global climate system: - "Arctic Ocean History: From Speculation to Reality" (Bremerhaven/Germany, November 2008); - "Overcoming barriers to Arctic Ocean scientific drilling: the site survey challenge" (Copenhagen/Denmark, November 2011); - Circum-Arctic shelf/upper continental slope scientific drilling workshop on "Catching Climate Change in Progress" (San Francisco/USA, December 2011); - "Coordinated Scientific Drilling in the Beaufort Sea: Addressing

  15. Increasing coastal slump activity impacts the release of sediment and organic carbon into the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    J. L. Ramage

    2018-03-01

    Full Text Available Retrogressive thaw slumps (RTSs are among the most active thermokarst landforms in the Arctic and deliver a large amount of material to the Arctic Ocean. However, their contribution to the organic carbon (OC budget is unknown. We provide the first estimate of the contribution of RTSs to the nearshore OC budget of the Yukon Coast, Canada, and describe the evolution of coastal RTSs between 1952 and 2011 in this area. We (1 describe the evolution of RTSs between 1952 and 2011; (2 calculate the volume of eroded material and stocks of OC mobilized through slumping, including soil organic carbon (SOC and dissolved organic carbon (DOC; and (3 estimate the OC fluxes mobilized through slumping between 1972 and 2011. We identified RTSs using high-resolution satellite imagery from 2011 and geocoded aerial photographs from 1952 and 1972. To estimate the volume of eroded material, we applied spline interpolation on an airborne lidar dataset acquired in July 2013. We inferred the stocks of mobilized SOC and DOC from existing related literature. Our results show a 73 % increase in the number of RTSs and 14 % areal expansion between 1952 and 2011. In the study area, RTSs displaced at least 16.6×106 m3 of material, 53 % of which was ice, and mobilized 145.9×106 kg of OC. Between 1972 and 2011, 49 RTSs displaced 8.6×103 m3 yr−1 of material, adding 0.6 % to the OC flux released by coastal retreat along the Yukon Coast. Our results show that the contribution of RTSs to the nearshore OC budget is non-negligible and should be included when estimating the quantity of OC released from the Arctic coast to the ocean.

  16. Synechococcus in the Atlantic gateway to the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Maria Lund Paulsen

    2016-10-01

    Full Text Available Increasing temperatures, with pronounced effects at high latitudes, have raised questions about potential changes in species composition, as well as possible increased importance of small-celled phytoplankton in marine systems. In this study, we mapped out one of the smallest and globally most widespread primary producers, the picocyanobacterium Synechococcus, within the Atlantic inflow to the Arctic Ocean. In contrast to the general understanding that Synechococcus is almost absent in polar oceans due to low temperatures, we encountered high abundances (up to 21,000 cells mL-1 at 79 °N, and documented their presence as far north as 82.5 °N. Covering an annual cycle in 2014, we found that during autumn and winter, Synechococcus was often more abundant than picoeukaryotes, which usually dominate the picophytoplankton communities in the Arctic. Synechococcus community composition shifted from a quite high genetic diversity during the spring bloom to a clear dominance of two specific operational taxonomic units (OTUs in autumn and winter. We observed abundances higher than 1,000 cells mL-1 in water colder than 2 °C at seven distinct stations and size-fractionation experiments demonstrated a net growth of Synechococcus at 2 °C in the absence of nano-sized grazers at certain periods of the year. Phylogenetic analysis of petB sequences demonstrated that these high latitude Synechococcus group within the previously described cold-adapted clades I and IV, but also contributed to unveil novel genetic diversity, especially within clade I.

  17. Response of halocarbons to ocean acidification in the Arctic

    Directory of Open Access Journals (Sweden)

    F. E. Hopkins

    2013-04-01

    Full Text Available The potential effect of ocean acidification (OA on seawater halocarbons in the Arctic was investigated during a mesocosm experiment in Spitsbergen in June–July 2010. Over a period of 5 weeks, natural phytoplankton communities in nine ~ 50 m3 mesocosms were studied under a range of pCO2 treatments from ~ 185 μatm to ~ 1420 μatm. In general, the response of halocarbons to pCO2 was subtle, or undetectable. A large number of significant correlations with a range of biological parameters (chlorophyll a, microbial plankton community, phytoplankton pigments were identified, indicating a biological control on the concentrations of halocarbons within the mesocosms. The temporal dynamics of iodomethane (CH3I alluded to active turnover of this halocarbon in the mesocosms and strong significant correlations with biological parameters suggested a biological source. However, despite a pCO2 effect on various components of the plankton community, and a strong association between CH3I and biological parameters, no effect of pCO2 was seen in CH3I. Diiodomethane (CH2I2 displayed a number of strong relationships with biological parameters. Furthermore, the concentrations, the rate of net production and the sea-to-air flux of CH2I2 showed a significant positive response to pCO2. There was no clear effect of pCO2 on bromocarbon concentrations or dynamics. However, periods of significant net loss of bromoform (CHBr3 were found to be concentration-dependent, and closely correlated with total bacteria, suggesting a degree of biological consumption of this halocarbon in Arctic waters. Although the effects of OA on halocarbon concentrations were marginal, this study provides invaluable information on the production and cycling of halocarbons in a region of the world's oceans likely to experience rapid environmental change in the coming decades.

  18. The relation between Arctic Ocean circulation and the Arctic Oscillation as revealed by satellite altimetry and gravimetry

    Science.gov (United States)

    Morison, J.; Kwok, R.; Peralta Ferriz, C.; Dickinson, S.; Morison, D.; Andersen, R.; Dewey, S.

    2017-12-01

    Arctic Ocean circulation is commonly characterized by the persistent anticyclonic Beaufort Gyre in the Canada Basin and the Transpolar Drift. While these are clearly important features, their role in changing Arctic Ocean circulation is at times distorted by sampling biases inherent in drifting buoy and standard shipboard measurements of western nations. Hydrographic measurements from SCICEX submarine cruises for science in the early 1990s revealed an increasingly cyclonic circulation along the Russian side of the Arctic Ocean related to the low sea level pressure pattern in the same region associated with a high Arctic Oscillation (AO) index. More recently satellite altimetry (ICESat and CryoSat2) and gravimetry (GRACE) have provided the basin-wide observational coverage needed to see shifts to increased cyclonic circulation in 2004 to 2008 and decreased cyclonic circulation in 2008 to 2015. These shifts are related to changes in the AO and are important for their effect on the trajectories of sea ice and freshwater through the Arctic Ocean.

  19. Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean.

    Science.gov (United States)

    Gazeau, Frédéric; van Rijswijk, Pieter; Pozzato, Lara; Middelburg, Jack J

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study.

  20. Scientific Drilling in the Arctic Ocean: A challenge for the next decades

    Science.gov (United States)

    Stein, R.; Coakley, B.

    2009-04-01

    Although major progress in Arctic Ocean research has been made during the last decades, the knowledge of its short- and long-term paleoceanographic and paleoclimatic history as well as its plate-tectonic evolution is much behind that from the other world's oceans. That means - despite the importance of the Arctic in the climate system - the data base we have from this area is still very weak, and large parts of the climate history have not been recovered at all in sedimentary sections. This lack of knowledge is mainly caused by the major technological/ logistic problems in reaching this permanently ice-covered region with normal research vessels and in retrieving long and undisturbed sediment cores. With the successful completion of IODP Expedition 302 ("Arctic Coring Expedition" - ACEX), the first Mission Specific Platform (MSP) expedition within the Integrated Ocean Drilling Program - IODP, a new era in Arctic research has begun. For the first time, a scientific drilling in the permanently ice-covered Arctic Ocean was carried out, penetrating about 430 meters of Quaternary, Neogene, Paleogene and Campanian sediment on the crest of Lomonosov Ridge close to the North Pole. The success of ACEX has certainly opened the door for further scientific drilling in the Arctic Ocean, and will frame the next round of questions to be answered from new drill holes to be taken during the next decades. In order to discuss and plan the future of scientific drilling in the Arctic Ocean, an international workshop was held at the Alfred Wegener Institute (AWI) in Bremerhaven/Germany, (Nov 03-05, 2008; convenors: Bernard Coakley/University of Alaska Fairbanks and Ruediger Stein/AWI Bremerhaven). About 95 scientists from Europe, US, Canada, Russia, Japan, and Korea, and observers from oil companies participated in the workshop. Funding of the workshop was provided by the Consortium for Ocean Leadership (US), the European Science Foundation, the Arctic Ocean Sciences Board, and the

  1. Changes in Ocean Circulation with an Ice-Free Arctic: Reconstructing Early Holocene Arctic Ocean Circulation Using Geochemical Signals from Individual Neogloboquadrina pachyderma (sinistral) Shells

    Science.gov (United States)

    Livsey, C.; Spero, H. J.; Kozdon, R.

    2016-12-01

    The impacts of sea ice decrease and consequent hydrologic changes in the Arctic Ocean will be experienced globally as ocean and atmospheric temperatures continue to rise, though it is not evident to what extent. Understanding the structure of the Arctic water column during the early/mid Holocene sea ice minimum ( 6-10 kya), a post-glacial analogue of a seasonally ice-free Arctic, will help us to predict what the changes we can expect as the Earth warms over the next century. Neogloboquadrina pachyderma (sinistral; Nps) is a species of planktonic foraminifera that dominates assemblages in the polar oceans. This species grows its chambers (ontogenetic calcite) in the surface waters and subsequently descends through the water column to below the mixed layer where it quickly adds a thick crust of calcite (Kohfeld et al., 1996). Therefore, geochemical signals from both the surface waters and sub-mixed layer depths are captured within single Nps shells. We were able to target ion mass spectrometry (SIMS), therefore capturing signals from both the ontogenetic and crust calcite in single Nps shells. This data was combined with laser ablation- inductively coupled mass spectrometry (LA-ICPMS) Mg/Ca profiles of trace metals through the two layers of calcite of the same shells, to determine the thermal structure of the water column. Combining δ18O, temperature, and salinity gradients from locations across the Arctic basin allow us to reconstruct the hydrography of the early Holocene Arctic sea ice minimum. These results will be compared with modern Arctic water column characteristics in order to develop a conceptual model of Arctic Ocean oceanographic change due to global warming. Kohfeld, K.E., Fairbanks, R.G., Smith, S.L., Walsh, I.D., 1996. Neogloboquadrina pachyderma(sinistral coiling) as paleoceanographic tracers in polar oceans: Evidence from northeast water polynya plankton tows, sediment traps, and surface sediments. Paleoceanography 11, 679-699.

  2. International Bathymetric Chart of the Arctic Ocean, Version 3.0

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — IBCAO Version 3.0 represents the largest improvement since 1999 taking advantage of new data sets collected by the circum-Arctic nations, opportunistic data...

  3. Effects of an Arctic Ocean Ski Traverse on the Protective Capabilities of Expedition Footwear

    National Research Council Canada - National Science Library

    Endrusick, Thomas; Frykman, Peter; O'Brien, Catherine; Giblo, Joseph

    2005-01-01

    A traverse of the Arctic Ocean during a 2000-km unsupported ski expedition provided an opportunity to assess the impact of an extreme cold environment on the protective capabilities of a specialized footwear system (FS...

  4. North Pole Environmental Observatory CTD surveys: Springtime temperature and salinity measurements in the Arctic Ocean by aircraft, 2000 - 2008 (NODC Accession 0057592)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The investigators propose to take annual springtime, large-scale airborne surveys of the Arctic Ocean. These surveys will be in two regions: the central Arctic Ocean...

  5. Arctic-HYCOS: a Large Sample observing system for estimating freshwater fluxes in the drainage basin of the Arctic Ocean

    Science.gov (United States)

    Pietroniro, Al; Korhonen, Johanna; Looser, Ulrich; Hardardóttir, Jórunn; Johnsrud, Morten; Vuglinsky, Valery; Gustafsson, David; Lins, Harry F.; Conaway, Jeffrey S.; Lammers, Richard; Stewart, Bruce; Abrate, Tommaso; Pilon, Paul; Sighomnou, Daniel; Arheimer, Berit

    2015-04-01

    The Arctic region is an important regulating component of the global climate system, and is also experiencing a considerable change during recent decades. More than 10% of world's river-runoff flows to the Arctic Ocean and there is evidence of changes in its fresh-water balance. However, about 30% of the Arctic basin is still ungauged, with differing monitoring practices and data availability from the countries in the region. A consistent system for monitoring and sharing of hydrological information throughout the Arctic region is thus of highest interest for further studies and monitoring of the freshwater flux to the Arctic Ocean. The purpose of the Arctic-HYCOS project is to allow for collection and sharing of hydrological data. Preliminary 616 stations were identified with long-term daily discharge data available, and around 250 of these already provide online available data in near real time. This large sample will be used in the following scientific analysis: 1) to evaluate freshwater flux to the Arctic Ocean and Seas, 2) to monitor changes and enhance understanding of the hydrological regime and 3) to estimate flows in ungauged regions and develop models for enhanced hydrological prediction in the Arctic region. The project is intended as a component of the WMO (World Meteorological Organization) WHYCOS (World Hydrological Cycle Observing System) initiative, covering the area of the expansive transnational Arctic basin with participation from Canada, Denmark, Finland, Iceland, Norway, Russian Federation, Sweden and United States of America. The overall objective is to regularly collect, manage and share high quality data from a defined basic network of hydrological stations in the Arctic basin. The project focus on collecting data on discharge and possibly sediment transport and temperature. Data should be provisional in near-real time if available, whereas time-series of historical data should be provided once quality assurance has been completed. The

  6. A model study of the first ventilated regime of the Arctic Ocean during the early Miocene

    Directory of Open Access Journals (Sweden)

    Bijoy Thompson

    2012-07-01

    Full Text Available The tectonic opening of Fram Strait during the Neogene was a significant geological event that transferred the Arctic Ocean from a poorly ventilated enclosed basin, with weak exchange with the North Atlantic, to a fully ventilated “ocean stage”. Previous tectonic and physical oceanographic analyses suggest that the early Miocene Fram Strait was likely several times narrower and less than half as deep as the present-day 400 km wide and 2550 m deep strait. Here we use an ocean general circulation model with a passive age tracer included to further address the effect of the Fram Strait opening on the early Miocene Arctic Ocean circulation. The model tracer age exhibits strong spatial gradient between the two major Arctic Ocean deep basins: the Eurasian and Amerasian basins. There is a two-layer stratification and the exchange flow through Fram Strait shows a bi-layer structure with a low salinity outflow from the Arctic confined to a relatively thin upper layer and a saline inflow from the North Atlantic below. Our study suggests that although Fram Strait was significantly narrower and shallower during early Miocene, and the ventilation mechanism quite different in our model, the estimated ventilation rates are comparable to the chemical tracer estimates in the present-day Arctic Ocean. Since we achieved ventilation of the Arctic Ocean with a prescribed Fram Strait width of 100 km and sill depth of 1000 m, ventilation may have preceded the timing of a full ocean depth connection between the Arctic Ocean and North Atlantic established through seafloor spreading and the development of the Lena Trough.

  7. 77 FR 2513 - Draft Environmental Impact Statement for Effects of Oil and Gas Activities in the Arctic Ocean

    Science.gov (United States)

    2012-01-18

    ... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration RIN 0648-XA934 Draft Environmental Impact Statement for Effects of Oil and Gas Activities in the Arctic Ocean AGENCY: National Marine... Environmental Impact Statement (DEIS) for the Effects of Oil and Gas Activities in the Arctic Ocean.'' Based on...

  8. Spatial Distributions of DDTs in the Water Masses of the Arctic Ocean.

    Science.gov (United States)

    Carrizo, Daniel; Sobek, Anna; Salvadó, Joan A; Gustafsson, Örjan

    2017-07-18

    There is a scarcity of data on the amount and distribution of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) and its metabolites in intermediate and deep ocean water masses. Here, the distribution and inventories of DDTs in water of the Arctic shelf seas and the interior basin are presented. The occurrence of ∑ 6 DDT (0.10-66 pg L -1 ) in the surface water was dominated by 4,4'-DDE. In the Central Arctic Ocean increasing concentrations of DDE with depth were observed in the Makarov and Amundsen basins. The increasing concentrations down to 2500 m depth is in accordance with previous findings for PCBs and PBDEs. Similar concentrations of DDT and DDEs were found in the surface water, while the relative contribution of DDEs increased with depth, demonstrating a transformation over time and depth. Higher concentrations of DDTs were found in the European part of the Arctic Ocean; these distributions likely reflect a combination of different usage patterns, transport, and fate of these compounds. For instance, the elevated concentrations of DDTs in the Barents and Atlantic sectors of the Arctic Ocean indicate the northbound Atlantic current as a significant conveyor of DDTs. This study contributes to the very rare data on OCPs in the vast deep-water compartments and combined with surface water distribution across the Arctic Ocean helps to improve our understanding of the large-scale fate of DDTs in the Arctic.

  9. Evidence for ice-ocean albedo feedback in the Arctic Ocean shifting to a seasonal ice zone.

    Science.gov (United States)

    Kashiwase, Haruhiko; Ohshima, Kay I; Nihashi, Sohey; Eicken, Hajo

    2017-08-15

    Ice-albedo feedback due to the albedo contrast between water and ice is a major factor in seasonal sea ice retreat, and has received increasing attention with the Arctic Ocean shifting to a seasonal ice cover. However, quantitative evaluation of such feedbacks is still insufficient. Here we provide quantitative evidence that heat input through the open water fraction is the primary driver of seasonal and interannual variations in Arctic sea ice retreat. Analyses of satellite data (1979-2014) and a simplified ice-upper ocean coupled model reveal that divergent ice motion in the early melt season triggers large-scale feedback which subsequently amplifies summer sea ice anomalies. The magnitude of divergence controlling the feedback has doubled since 2000 due to a more mobile ice cover, which can partly explain the recent drastic ice reduction in the Arctic Ocean.

  10. Splitting of Atlantic water transport towards the Arctic Ocean into the Fram Strait and Barents Sea Branches - mechanisms and consequences

    Science.gov (United States)

    Beszczynska-Möller, Agnieszka; Skagseth, Øystein; von Appen, Wilken-Jon; Walczowski, Waldemar; Lien, Vidar

    2016-04-01

    The heat content in the Arctic Ocean is to a large extent determined by oceanic advection from the south. During the last two decades the extraordinary warm Atlantic water (AW) inflow has been reported to progress through the Nordic Seas into the Arctic Ocean. Warm anomalies can result from higher air temperatures (smaller heat loss) in the Nordic Seas, and/or from an increased oceanic advection. But the ultimate fate of warm anomalies of Atlantic origin depends strongly on their two possible pathways towards the Arctic Ocean. The AW temperature changes from 7-10°C at the entrance to the Nordic Seas, to 6-6.5°C in the Barents Sea opening and 3-3.5°C as the AW leaving Fram Strait enters the Arctic Ocean. When AW passes through the shallow Barents Sea, nearly all its heat is lost due to atmospheric cooling and AW looses its signature. In the deep Fram Strait the upper part of Atlantic water becomes transformed into a less saline and colder surface layer and thus AW preserves its warm core. A significant warming and high variability of AW volume transport was observed in two recent decades in the West Spitsbergen Current, representing the Fram Strait Branch of Atlantic inflow. The AW inflow through Fram Strait carries between 26 and 50 TW of heat into the Arctic Ocean. While the oceanic heat influx to the Barents Sea is of a similar order, the heat leaving it through the northern exit into the Arctic Ocean is negligible. The relative strength of two Atlantic water branches through Fram Strait and the Barents Sea governs the oceanic heat transport into the Arctic Ocean. According to recently proposed mechanism, the Atlantic water flow in the Barents Sea Branch is controlled by the strength of atmospheric low over the northern Barents Sea, acting through a wind-induced Ekman divergence, which intensifies eastward AW flow. The Atlantic water transport in the Fram Strait Branch is mainly forced by the large-scale low-pressure system over the eastern Norwegian and

  11. Shallow methylmercury production in the marginal sea ice zone of the central Arctic Ocean.

    Science.gov (United States)

    Heimbürger, Lars-Eric; Sonke, Jeroen E; Cossa, Daniel; Point, David; Lagane, Christelle; Laffont, Laure; Galfond, Benjamin T; Nicolaus, Marcel; Rabe, Benjamin; van der Loeff, Michiel Rutgers

    2015-05-20

    Methylmercury (MeHg) is a neurotoxic compound that threatens wildlife and human health across the Arctic region. Though much is known about the source and dynamics of its inorganic mercury (Hg) precursor, the exact origin of the high MeHg concentrations in Arctic biota remains uncertain. Arctic coastal sediments, coastal marine waters and surface snow are known sites for MeHg production. Observations on marine Hg dynamics, however, have been restricted to the Canadian Archipelago and the Beaufort Sea (Ocean (79-90 °N) profiles for total mercury (tHg) and MeHg. We find elevated tHg and MeHg concentrations in the marginal sea ice zone (81-85 °N). Similar to other open ocean basins, Arctic MeHg concentration maxima also occur in the pycnocline waters, but at much shallower depths (150-200 m). The shallow MeHg maxima just below the productive surface layer possibly result in enhanced biological uptake at the base of the Arctic marine food web and may explain the elevated MeHg concentrations in Arctic biota. We suggest that Arctic warming, through thinning sea ice, extension of the seasonal sea ice zone, intensified surface ocean stratification and shifts in plankton ecodynamics, will likely lead to higher marine MeHg production.

  12. An Improved 20-Year Arctic Ocean Altimetric Sea Level Data Record

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Andersen, Ole Baltazar; Knudsen, Per

    2015-01-01

    For ocean and climate research, it is essential to get long-term altimetric sea level data that is as accurate as possible. However, the accuracy of the altimetric data is frequently degraded in the interior of the Arctic Ocean due to the presence of seasonal or permanent sea ice. We have reproce...

  13. Mooring-based long-term observation of oceanographic condition in the Chukchi Ses and Canada Basin of the Arctic Ocean

    Science.gov (United States)

    Kikuchi, Takashi; Itoh, Motoyo; Nishino, Shigeto; Watanabe, Eiji

    2015-04-01

    Changes of the Arctic Ocean environment are well known as one of the most remarkable evidences of global warming, attracting social and public attentions as well as scientists'. However, to illustrate on-going changes and predict future condition of the Arctic marine environment, we still do not have enough knowledge of Arctic sea ice and marine environment. In particular, lack of observation data in winter, e.g., under sea ice, still remains a key issue for precise understanding of seasonal cycle on oceanographic condition in the Arctic Ocean. Mooring-based observation is one of the most useful methods to collect year-long data in the Arctic Ocean. We have been conducting long-term monitoring using mooring system in the Pacific sector of the Arctic Ocean. Volume, heat, and freshwater fluxes through Barrow Canyon where is a major conduit of Pacific-origin water-masses into the Canada Basin have been observed since 2000. We show from an analysis of the mooring results that volume flux through Barrow Canyon was about 60 % of Bering Strait volume flux. Averaged heat flux ranges from 0.9 to 3.07 TW, which could melt 88,000 to 300,000 km2 of 1m thick ice in the Canada Basin, which likely contributed to sea ice retreat in the Pacific sector of the Arctic Ocean. In winter, we found inter-annual variability in salinity related to coastal polynya activity in the Chukchi Sea. In collaboration with Distributed Biological Observatory (DBO) project, which is one of the tasks of Sustaining Arctic Observing Network (SAON), we also initiated year-long mooring observation in the Hope Valley of the southern Chukchi Sea since 2012. Interestingly, winter oceanographic conditions in the Hope Valley are greatly different between in 2012-2013 and in 2013-2014. We speculate that differences of sea ice freeze-up and coastal polynya activity in the southern Chukchi Sea cause significant difference of winter oceanographic condition. It suggests that recent sea ice reduction in the Pacific

  14. Nondestructive X-Ray Computed Tomography Analysis of Sediment Cores: A Case Study from the Arctic Ocean

    Science.gov (United States)

    Oti, E.; Polyak, L. V.; Cook, A.; Dipre, G.

    2014-12-01

    Investigation of marine sediment records can help elucidate recent changes in the Arctic Ocean circulation and sea ice conditions. We examine sediment cores from the western Arctic Ocean, representing Late to Early Quaternary age (potentially up to 1 Ma). Previous studies of Arctic sediment cores indicate that interglacial/interstadial periods with relatively high sea levels and reduced ice cover are characterized by vigorous bioturbation, while glacial intervals have little to no bioturbation. Traditional methods for studying bioturbation require physical dissection of the cores, effectively destroying them. To treat this limitation, we evaluate archival sections of the cores using an X-ray Computed Tomography (XCT) scanner, which noninvasively images the sediment cores in three dimensions. The scanner produces density sensitive images suitable for quantitative analysis and for identification of bioturbation based on size, shape, and orientation. We use image processing software to isolate burrows from surrounding sediment, reconstruct them three-dimensionally, and then calculate their surface areas, volumes, and densities. Preliminary analysis of a core extending to the early Quaternary shows that bioturbation ranges from 0 to approximately 20% of the core's volume. In future research, we will quantitatively define the relationship between bioturbation activity and glacial regimes. XCT examination of bioturbation and other sedimentary features has the potential to shed light on paleoceanographic conditions such as sedimentation patterns and food flux. XCT is an alternative, underexplored investigation method that bears implications not only for illustrating paleoclimate variations but also for preserving cores for future, more advanced technologies.

  15. Arctide2017, a high-resolution regional tidal model in the Arctic Ocean

    DEFF Research Database (Denmark)

    Cancet, M.; Andersen, O. B.; Lyard, F.

    2018-01-01

    The Arctic Ocean is a challenging region for tidal modelling. The accuracy of the global tidal models decreases by several centimeters in the Polar Regions, which has a large impact on the quality of the satellite altimeter sea surface heights and the altimetry-derived products. NOVELTIS, DTU Space...... and LEGOS have developed Arctide2017, a regional, high-resolution tidal atlas in the Arctic Ocean, in the framework of an extension of the CryoSat Plus for Ocean (CP4O) ESA STSE (Support to Science Element) project. In particular, this atlas benefits from the assimilation of the most complete satellite...... assimilation and validation. This paper presents the implementation methodology and the performance of this new regional tidal model in the Arctic Ocean, compared to the existing global and regional tidal models....

  16. Geochemistry of clathrate-derived methane in Arctic Ocean waters

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, S.M.; Reagan, M.T.; Moridis, G.J.; Cameron-Smith, P.J.

    2010-03-15

    Alterations to the composition of seawater are estimated for microbial oxidation of methane from large polar clathrate destabilizations, which may arise in the coming century. Gas fluxes are taken from porous flow models of warming Arctic sediment. Plume spread parameters are then used to bracket the volume of dilution. Consumption stoichiometries for the marine methanotrophs are based on growth efficiency and elemental/enzyme composition data. The nutritional demand implied by extra CH{sub 4} removal is compared with supply in various high latitude water masses. For emissions sized to fit the shelf break, reaction potential begins at one hundred micromolar and falls to order ten a thousand kilometers downstream. Oxygen loss and carbon dioxide production are sufficient respectively to hypoxify and acidify poorly ventilated basins. Nitrogen and the monooxygenase transition metals may be depleted in some locations as well. Deprivation is implied relative to existing ecosystems, along with dispersal of the excess dissolved gas. Physical uncertainties are inherent in the clathrate abundance, patch size, outflow buoyancy and mixing rate. Microbial ecology is even less defined but may involve nutrient recycling and anaerobic oxidizers.

  17. Dazzled by ice and snow: improving medium ocean color images in Arctic waters

    Science.gov (United States)

    Babin, M.; Goyens, C.; Belanger, S.

    2016-02-01

    The importance of phytoplankton blooms for the Arctic marine ecosystem is well recognized but studies disagree as the consequences of sea ice melt on the phytoplankton distribution and growth. This limited understanding in actual and future Arctic phytoplankton dynamics mostly results from a lack of accurate data at the receding ice-edges where phytoplankton blooms are known to occur. Ocean color sensors on-board satellites represent therefore a crucial tool providing a synoptic view of the ocean systems over broad spatio-temporal scales. However, today the use of ocean color data in Arctic environments remains strongly compromised due to, among others, sea ice contamination. Indeed, medium ocean color data along the receding ice edge are "dazzled" by nearby and/or sub-pixel highly reflective ice floes. Standard ocean color data methods ignore ice-contamination during data processing which deteriorates the quality of the radiometric data and subsequent satellite derived bio-geochemical products. Moreover, since Arctic phytoplankton spring blooms typically develop along the receding ice-edges, ignoring ice-contaminated pixels may lead to wrong interpretation of satellite data. The present study shows how adjacent and sub-pixel sea-ice floes affect the retrieved ocean color data. A correction approach is also suggested to improve the "dazzled" ocean color pixels along the receding ice edge in the aim to provide additional support to better understand current and future trends in phytoplankton dynamics.

  18. Arctic Ocean gravity, geoid and sea-ice freeboard heights from ICESat and GRACE

    DEFF Research Database (Denmark)

    Forsberg, René; Skourup, Henriette

    2005-01-01

    Gravity Project in combination with GRACE gravity field models to derive an improved Arctic geoid model. This model is then used to convert ICESat measurements to sea-ice freeboard heights with a coarse lowest-level surface method. The derived freeboard heights show a good qualitative agreement...... all major tectonic features of the Arctic Ocean, and has an accuracy of 6 mGal compared to recent airborne gravity data, illustrating the usefulness of ICESat data for gravity field determination....

  19. U.S. Capability to Support Ocean Engineering in the Arctic.

    Science.gov (United States)

    1984-11-01

    ntinudoladgsdvlpetlh Arctic will have an effect on its physical and biolociral U.S. Capability *to Support Ocean Engineering in the Arctic Committee on Assessment of...Richard J. Seymour * Exxon Production Research Scripps Institution of Oceanography - Houston, Texas La Jolla, California William Creelman William H... physical and biological environment. A subject of concern and controversy has been the potential effect that oil and gas activities may have on the

  20. Genetic Diversity of Eukaryotic Picoplankton in the Arctic Ocean (Fram Strait)

    OpenAIRE

    Kilias, Estelle; Nöthig, Eva-Maria; Peeken, Ilka; Wolf, Christian; Metfies, Katja

    2011-01-01

    Climate change is expected to be particularly intense in the Arctic Ocean having as well extensive consequences on Arctic pelagic ecosystems. Thus, evaluations of the impact on the base of the food web, on local phytoplankton communities, are required. Prerequisite of such an evaluation is comprehensive information about the present phytoplankton diversity and distribution. Recent investigations indicate that rising temperatures as well as freshening of surface waters in the marine environmen...

  1. Oceanographic temperature and salinity measurements collected using drifting buoys in the Arctic Ocean from 2003 to 2006 (NODC Accession 0014672)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic temperature and salinity measurements collected using drifting buoys in the Arctic Ocean. Data from JAMSTEC drifting buoys which were deployed both as...

  2. Hydrographic changes in the Lincoln Sea in the Arctic Ocean with focus on an upper ocean freshwater anomaly between 2007 and 2010

    NARCIS (Netherlands)

    de Steur, L.; Steele, M.; Hansen, E.; Morison, J.; Polyakov, I.; Olsen, S.M.; Melling, H.; McLaughlin, F.A.; Kwok, R.; Smethie Jr., W.M.; Schlosser, P.

    2013-01-01

    Hydrographic data from the Arctic Ocean show that freshwater content in the Lincoln Sea, north of Greenland, increased significantly from 2007 to 2010, slightly lagging changes in the eastern and central Arctic. The anomaly was primarily caused by a decrease in the upper ocean salinity. In 2011

  3. Arctic Ocean sea ice cover during the penultimate glacial and the last interglacial.

    Science.gov (United States)

    Stein, Ruediger; Fahl, Kirsten; Gierz, Paul; Niessen, Frank; Lohmann, Gerrit

    2017-08-29

    Coinciding with global warming, Arctic sea ice has rapidly decreased during the last four decades and climate scenarios suggest that sea ice may completely disappear during summer within the next about 50-100 years. Here we produce Arctic sea ice biomarker proxy records for the penultimate glacial (Marine Isotope Stage 6) and the subsequent last interglacial (Marine Isotope Stage 5e). The latter is a time interval when the high latitudes were significantly warmer than today. We document that even under such warmer climate conditions, sea ice existed in the central Arctic Ocean during summer, whereas sea ice was significantly reduced along the Barents Sea continental margin influenced by Atlantic Water inflow. Our proxy reconstruction of the last interglacial sea ice cover is supported by climate simulations, although some proxy data/model inconsistencies still exist. During late Marine Isotope Stage 6, polynya-type conditions occurred off the major ice sheets along the northern Barents and East Siberian continental margins, contradicting a giant Marine Isotope Stage 6 ice shelf that covered the entire Arctic Ocean.Coinciding with global warming, Arctic sea ice has rapidly decreased during the last four decades. Here, using biomarker records, the authors show that permanent sea ice was still present in the central Arctic Ocean during the last interglacial, when high latitudes were warmer than present.

  4. Biological response to climate change in the Arctic Ocean: The view from the past

    Science.gov (United States)

    Cronin, Thomas M.; Cronin, Matthew A.

    2017-01-01

    The Arctic Ocean is undergoing rapid climatic changes including higher ocean temperatures, reduced sea ice, glacier and Greenland Ice Sheet melting, greater marine productivity, and altered carbon cycling. Until recently, the relationship between climate and Arctic biological systems was poorly known, but this has changed substantially as advances in paleoclimatology, micropaleontology, vertebrate paleontology, and molecular genetics show that Arctic ecosystem history reflects global and regional climatic changes over all timescales and climate states (103–107 years). Arctic climatic extremes include 25°C hyperthermal periods during the Paleocene-Eocene (56–46 million years ago, Ma), Quaternary glacial periods when thick ice shelves and sea ice cover rendered the Arctic Ocean nearly uninhabitable, seasonally sea-ice-free interglacials and abrupt climate reversals. Climate-driven biological impacts included large changes in species diversity, primary productivity, species’ geographic range shifts into and out of the Arctic, community restructuring, and possible hybridization, but evidence is not sufficient to determine whether or when major episodes of extinction occurred.

  5. New aero-gravity results from the Arctic: Linking the latest Cretaceous-early Cenozoic plate kinematics of the North Atlantic and Arctic Ocean

    DEFF Research Database (Denmark)

    Døssing, Arne; Hopper, J.R.; Olesen, Arne Vestergaard

    2013-01-01

    The tectonic history of the Arctic Ocean remains poorly resolved and highly controversial. Details regarding break up of the Lomonosov Ridge from the Barents-Kara shelf margins and the establishment of seafloor spreading in the Cenozoic Eurasia Basin are unresolved. Significantly, the plate...... tectonic evolution of the Mesozoic Amerasia Basin is essentially unknown. The Arctic Ocean north of Greenland is at a critical juncture that formed at the locus of a Mesozoic three-plate setting between the Lomonosov Ridge, Greenland, and North America. In addition, the area is close to the European plate...... plateau against an important fault zone north of Greenland. Our results provide new constraints for Cretaceous-Cenozoic plate reconstructions of the Arctic. Key Points Presentation of the largest aero-gravity survey acquired over the Arctic Ocean Plate tectonic link between Atlantic and Arctic spreading...

  6. Impact of CryoSat-2 for marine gravity field - globally and in the Arctic Ocean

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Stenseng, Lars; Knudsen, Per

    GDR data, NOAA LRM data, but also Level1b (LRM, SAR and SAR-in waveforms) data have been analyzed. A suite of eight different empirical retrackers have been developed and investigated for their ability to predict marine gravity in the Arctic Ocean. The impact of the various improvement offered by Cryo...... days repeat offered by CryoSat-2 provides denser coverage than older geodetic mission data set like ERS-1. Thirdly, the 92 degree inclination of CryoSat-2 is designed to map more of the Arctic Ocean than previous altimetric satellites. Finally, CryoSat-2 is able to operate in two new modes (SAR and SAR......Sat-2 in comparison with conventional satellite altimetry have been studied and quantified both globally but particularly for the Arctic Ocean using a large number of marine and airborne surveys providing “ground truth” marine gravity....

  7. Late Pleistocene and Holocene meltwater events in the western Arctic Ocean

    Science.gov (United States)

    Poore, R.Z.; Osterman, L.; Curry, W.B.; Phillips, R.L.

    1999-01-01

    Accelerator mass spectrometer 14C dated stable isotope data from Neogloboquadrina pachyerma in cores raised from the Mendeleyev Ridge and slope provide evidence for significant influx of meltwater to the western Arctic Ocean during the early part of marine oxygen isotope stage 1 (OIS 1) and during several intervals within OIS 3. The strongest OIS 3 meltwater event occurred before ca. 45 ka (conventional radiocarbon age) and was probably related to the deglaciation at the beginning of OIS 3. Major meltwater input to the western Arctic Ocean during the last deglaciation coincides closely with the maximum rate of global sea-level rise as determined from the Barbados sea-level record, demonstrating a strong link between the global record and changes in the central Arctic Ocean. OIS 2, which includes the last glacial maximum, is very condensed or absent in the cores. Abundance and ??13C values for N. pachyderma in the middle part of OIS 3 are similar to modern values, indicating high productivity and seasonal ice-free areas along the Arctic margin at that time. These records indicate that the Arctic Ocean was a source of heat and moisture to the northern polar atmosphere during parts of OIS 3.

  8. Using an Environmental Intelligence Framework to Evaluate the Impacts of Ocean Acidification in the Arctic

    Science.gov (United States)

    Mathis, J. T.; Baskin, M.; Cross, J.

    2016-12-01

    The highly productive coastal seas of the Arctic Ocean are located in areas that are projected to experience strong global change, including rapid transitions in temperature and ocean acidification-driven changes in pH and other chemical parameters. Many of the marine organisms that may be most intensely affected by ocean acidification (OA) and other environmental stressors contribute substantially to the commercial fisheries of the Bering Sea and traditional subsistence food supplies across the Arctic. This could represent a looming challenge in many communities as the average prevalence of household food insecurity and very low food security in Alaska are already 12 percent and 4.3 percent, respectively. Here, we evaluate the patterns of dependence on marine resources within Alaska's Arctic that could be negatively impacted by OA and current community characteristics to assess the potential risk to the fishery sector from OA. We used a risk assessment framework to analyze an earth-system global model of ocean chemistry, fisheries harvest data, and demographic information. The analysis showed that regions around Alaska vary in their vulnerability to OA, but that each one will have to deal with possible impacts. Therefore, OA merits consideration in policy planning, as it may represent another challenge to Alaskan communities, some of which are already under acute socio-economic strains. With this in mind, we will present a number of adaptation strategies for communities living throughout Alaska's Arctic that could be applicable to other Arctic regions.

  9. Temperature dependence of CO2-enhanced primary production in the European Arctic Ocean

    KAUST Repository

    Holding, J. M.

    2015-08-31

    The Arctic Ocean is warming at two to three times the global rate1 and is perceived to be a bellwether for ocean acidification2, 3. Increased CO2 concentrations are expected to have a fertilization effect on marine autotrophs4, and higher temperatures should lead to increased rates of planktonic primary production5. Yet, simultaneous assessment of warming and increased CO2 on primary production in the Arctic has not been conducted. Here we test the expectation that CO2-enhanced gross primary production (GPP) may be temperature dependent, using data from several oceanographic cruises and experiments from both spring and summer in the European sector of the Arctic Ocean. Results confirm that CO2 enhances GPP (by a factor of up to ten) over a range of 145–2,099 μatm; however, the greatest effects are observed only at lower temperatures and are constrained by nutrient and light availability to the spring period. The temperature dependence of CO2-enhanced primary production has significant implications for metabolic balance in a warmer, CO2-enriched Arctic Ocean in the future. In particular, it indicates that a twofold increase in primary production during the spring is likely in the Arctic.

  10. Petroleum prospectivity of the Canada Basin, Arctic Ocean

    Science.gov (United States)

    Grantz, A.; Hart, P.E.

    2011-01-01

    Reconnaissance seismic reflection data indicate that Canada Basin is a remnant of the Amerasia Basin of the Arctic Ocean that lies south of the Alpha-Mendeleev Large Igneous Province, which was constructed on the northern part of the Amerasia Basin between about 127 and 89-75 Ma. Canada Basin is filled with Early Jurassic to Holocene detritus from the Mackenzie River system, which drains the northern third of interior North America, with sizable contributions from Alaska and Northwest Canada. Except for the absence of a salt- and shale-bearing mobile substrate Canada Basin is analogous to the Mississippi Delta and the western Gulf of Mexico. Canada Basin contains about 7 to >14 km of sediment beneath the Mackenzie Prodelta on the southeast, 6 to 7 km of sediment beneath the abyssal plain on the west, and roughly 5 or 6 million cubic km of sediment. About three fourths of the basin fill generates low amplitude seismic reflections, interpreted to represent hemiplegic deposits, and a fourth of the fill generates interbedded lenses to extensive layers of moderate to high amplitude reflections interpreted to represent unconfined turbidite and amalgamated channel deposits. Extrapolation from Arctic Alaska and Northwest Canada suggests that three fourths of the section in Canada Basin may contain intervals of hydrocarbon source rocks and the apparent age of the basin suggests that it contains three of the six stratigraphic intervals that together provided >90?? of the World's discovered reserves of oil and gas.. Worldwide heat flow averages suggest that about two thirds of Canada Basin lies in the oil or gas window. At least five types of structural or stratigraphic features of local to regional occurrence offer exploration targets in Canada Basin. These consist of 1) a belt of late Eocene to Miocene shale-cored detachment folds containing with at least two anticlines that are capped by beds with bright spots, 2) numerous moderate to high amplitude reflection packets

  11. Geochemistry and Flux of Terrigenous Dissolved Organic Matter to the Arctic Ocean

    Science.gov (United States)

    Spencer, R. G.; Mann, P. J.; Hernes, P. J.; Tank, S. E.; Striegl, R. G.; Dyda, R. Y.; Peterson, B. J.; McClelland, J. W.; Holmes, R. M.

    2011-12-01

    Rivers draining into the Arctic Ocean exhibit high concentrations of terrigenous dissolved organic carbon (DOC) and recent studies indicate that DOC export is changing due to climatic warming and alteration in permafrost condition. The fate of exported DOC in the Arctic Ocean is of key importance for understanding the regional carbon cycle and remains a point of discussion in the literature. As part of the Arctic Great Rivers Observatory (Arctic-GRO) project, samples were collected for DOC, chromophoric dissolved organic matter (CDOM) and lignin phenols from the Ob', Yenisey, Lena, Kolyma, Mackenzie and Yukon rivers in 2009 - 2010. DOC and lignin concentrations were elevated during the spring freshet and measurements related to DOC composition indicated an increasing contribution from terrestrial vascular plant sources at this time of year (e.g. lignin carbon-normalized yield, CDOM spectral slope, SUVA254, humic-like fluorescence). CDOM absorption was found to correlate strongly with both DOC (r2=0.83) and lignin concentration (r2=0.92) across the major arctic rivers. Utilizing these relationships we modeled loads for DOC and lignin export from high-resolution CDOM measurements (daily across the freshet) to derive improved flux estimates, particularly from the dynamic spring discharge maxima period when the majority of DOC and lignin export occurs. The new load estimates for DOC and lignin are higher than previous evaluations, emphasizing that if these are more representative of current arctic riverine export, terrigenous DOC is transiting through the Arctic Ocean at a faster rate than previously thought. It is apparent that higher resolution sampling of arctic rivers is exceptionally valuable with respect to deriving accurate fluxes and we highlight the potential of CDOM in this role for future studies and the applicability of in-situ CDOM sensors.

  12. The Arctic Summer Cloud-Ocean Study (ASCOS): overview and experimental design

    Science.gov (United States)

    Tjernström, M.; Leck, C.; Birch, C. E.; Brooks, B. J.; Brooks, I. M.; Bäcklin, L.; Chang, R. Y.-W.; Granath, E.; Graus, M.; Hansel, A.; Heintzenberg, J.; Held, A.; Hind, A.; de la Rosa, S.; Johnston, P.; Knulst, J.; de Leeuw, G.; Di Liberto, L.; Martin, M.; Matrai, P. A.; Mauritsen, T.; Müller, M.; Norris, S. J.; Orellana, M. V.; Orsini, D. A.; Paatero, J.; Persson, P. O. G.; Gao, Q.; Rauschenberg, C.; Ristovski, Z.; Sedlar, J.; Shupe, M. D.; Sierau, B.; Sirevaag, A.; Sjogren, S.; Stetzer, O.; Swietlicki, E.; Szczodrak, M.; Vaattovaara, P.; Wahlberg, N.; Westberg, M.; Wheeler, C. R.

    2013-05-01

    The climate in the Arctic is changing faster than anywhere else on Earth. Poorly understood feedback processes relating to Arctic clouds and aerosol-cloud interactions contribute to a poor understanding of the present changes in the Arctic climate system, and also to a large spread in projections of future climate in the Arctic. The problem is exacerbated by the paucity of research-quality observations in the central Arctic. Improved formulations in climate models require such observations, which can only come from measurements in-situ in this difficult to reach region with logistically demanding environmental conditions. The Arctic Summer Cloud-Ocean Study (ASCOS) was the most extensive central Arctic Ocean expedition with an atmospheric focus during the International Polar Year (IPY) 2007-2008. ASCOS focused on the study of the formation and life cycle of low-level Arctic clouds. ASCOS departed from Longyearbyen on Svalbard on 2 August and returned on 9 September 2008. In transit into and out of the pack ice, four short research stations were undertaken in the Fram Strait; two in open water and two in the marginal ice zone. After traversing the pack-ice northward an ice camp was set up on 12 August at 87°21' N 01°29' W and remained in operation through 1 September, drifting with the ice. During this time extensive measurements were taken of atmospheric gas and particle chemistry and physics, mesoscale and boundary-layer meteorology, marine biology and chemistry, and upper ocean physics. ASCOS provides a unique interdisciplinary data set for development and testing of new hypotheses on cloud processes, their interactions with the sea ice and ocean and associated physical, chemical, and biological processes and interactions. For example, the first ever quantitative observation of bubbles in Arctic leads, combined with the unique discovery of marine organic material, polymer gels with an origin in the ocean, inside cloud droplets suggest the possibility of primary

  13. Chukchi Borderland | Crustal Complex of the Amerasia Basin, Arctic Ocean

    Science.gov (United States)

    Ilhan, I.; Coakley, B.; Houseknecht, D. W.

    2017-12-01

    In the Arctic Ocean, Chukchi Borderland separates the North Chukchi shelf and Toll deep basins to the west and Canada deep basin to the east. Existing plate reconstructions have attempted to restore this north-striking, fragments of the continental crust to all margins of the Amerasia Basin based on sparse geologic and geophysical measurements. Regional multi-channel seismic reflection and potential field geophysics, and geologic data indicate it is a high standing continental block, requiring special accommodation to create a restorable model of the formation of the Amerasia Basin. The Borderland is composed of the Chukchi Plateau, Northwind Basin, and Northwind Ridge divided by mostly north striking normal faults. These offset the basement and bound a sequence of syn-tectonic sediments. Equivalent strata are, locally, uplifted, deformed and eroded. Seaward dipping reflectors (SDRs) are observed in the juncture between the North Chukchi, Toll basins, and southern Chukchi Plateau underlying a regional angular unconformity. This reveals that this rifted margin was associated with volcanism. An inferred condensed section, which is believed to be Hauterivian-Aptian in age, synchronous with the composite pebble shale and gamma-ray zone of the Alaska North Slope forms the basal sediments in the North Chukchi Basin. Approximately 15 km of post-rift strata onlap the condensed section, SDRs and, in part, the wedge sequence on the Chukchi Plateau from west to east, thinning to the north. These post-Aptian sediments imply that the rifted margin subsided no later than the earliest Cretaceous, providing a plausible time constraint for the inferred pre-Cretaceous rifting in this region. The recognition of SDRs and Hauterivian—Aptian condensed section, and continuity of the Early—Late Cretaceous post-rift strata along the margins of the Borderland, strike variations of the normal faults, absence of observable deformation along the Northwind Escarpment substantially constrain

  14. "Recent" macrofossil remains from the Lomonosov Ridge, central Arctic Ocean

    Science.gov (United States)

    Le Duc, Cynthia; de Vernal, Anne; Archambault, Philippe; Brice, Camille; Roberge, Philippe

    2016-04-01

    years as suggested by the radiocarbon dating of the upper centimeter of the sediment in PS87/030-2 (7792 ± 59 14C years BP), PS87/055-1 (3897 ± 41 14C years BP), and PS87/099-4 (1421 ± 66 14C years BP). Reference Stein, R. (Ed.), 2015. The Expedition PS87 of the Research Vessel Polarstern to the Arctic Ocean in 2014, Reports on Polar and Marine Research 688, Bremerhaven, Alfred Wegener Institute for Polar and Marine Research, 273 pp (http://epic.awi.de/37728/1/BzPM_0688_2015.pdf).

  15. Late-Middle Quaternary lithostratigraphy and sedimentation patterns on the Alpha Ridge, central Arctic Ocean: Implications for Arctic climate variability on orbital time scales

    Science.gov (United States)

    Wang, Rujian; Polyak, Leonid; Xiao, Wenshen; Wu, Li; Zhang, Taoliang; Sun, Yechen; Xu, Xiaomei

    2018-02-01

    We use sediment cores collected by the Chinese National Arctic Research Expeditions from the Alpha Ridge to advance Quaternary stratigraphy and paleoceanographic reconstructions for the Arctic Ocean. Our cores show a good litho/biostratigraphic correlation to sedimentary records developed earlier for the central Arctic Ocean, suggesting a recovered stratigraphic range of ca. 0.6 Ma, suitable for paleoclimatic studies on orbital time scales. This stratigraphy was tested by correlating the stacked Alpha Ridge record of bulk XRF manganese, calcium and zirconium (Mn, Ca, Zr), to global stable-isotope (LR04-δ18O) and sea-level stacks and tuning to orbital parameters. Correlation results corroborate the applicability of presumed climate/sea-level controlled Mn variations in the Arctic Ocean for orbital tuning. This approach enables better understanding of the global and orbital controls on the Arctic climate. Orbital tuning experiments for our records indicate strong eccentricity (100-kyr) and precession (∼20-kyr) controls on the Arctic Ocean, probably implemented via glaciations and sea ice. Provenance proxies like Ca and Zr are shown to be unsuitable as orbital tuning tools, but useful as indicators of glacial/deglacial processes and circulation patterns in the Arctic Ocean. Their variations suggest an overall long-term persistence of the Beaufort Gyre circulation in the Alpha Ridge region. Some glacial intervals, e.g., MIS 6 and 4/3, are predominated by material presumably transported by the Transpolar Drift. These circulation shifts likely indicate major changes in the Arctic climatic regime, which yet need to be investigated. Overall, our results demonstrate applicability of XRF data to paleoclimatic studies of the Arctic Ocean.

  16. A distributed atmosphere-sea ice-ocean observatory in the central Arctic Ocean: concept and first results

    Science.gov (United States)

    Hoppmann, Mario; Nicolaus, Marcel; Rabe, Benjamin; Wenzhöfer, Frank; Katlein, Christian; Scholz, Daniel; Valcic, Lovro

    2017-04-01

    To understand the current evolution of the Arctic Ocean towards a less extensive, thinner and younger sea ice cover is one of the biggest challenges in climate research. Especially the lack of simultaneous in-situ observations of sea ice, ocean and atmospheric properties leads to significant knowledge gaps in their complex interactions, and how the associated processes impact the polar marine ecosystem. Here we present a concept for the implementation of a long-term strategy to monitor the most essential climate- and ecosystem parameters in the central Arctic Ocean, year round and synchronously. The basis of this strategy is the development and enhancement of a number of innovative autonomous observational platforms, such as rugged weather stations, ice mass balance buoys, ice-tethered bio-optical buoys and upper ocean profilers. The deployment of those complementing platforms in a distributed network enables the simultaneous collection of physical and biogeochemical in-situ data on basin scales and year round, including the largely undersampled winter periods. A key advantage over other observatory systems is that the data is sent via satellite in near-real time, contributing to numerical weather predictions through the Global Telecommunication System (GTS) and to the International Arctic Buoy Programme (IABP). The first instruments were installed on ice floes in the Eurasian Basin in spring 2015 and 2016, yielding exceptional records of essential climate- and ecosystem-relevant parameters in one of the most inaccessible regions of this planet. Over the next 4 years, and including the observational periods of the Year of Polar Prediction (YOPP, 2017-2019) and the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC, 2020), the distributed observatory will be maintained by deployment of additional instruments in the central Arctic each year, benefitting from international logistical efforts.

  17. Summertime calcium carbonate undersaturation in shelf waters of the western Arctic Ocean – how biological processes exacerbate the impact of ocean acidification

    OpenAIRE

    N. R. Bates; M. I. Orchowska; R. Garley; J. T. Mathis

    2013-01-01

    The Arctic Ocean accounts for only 4% of the global ocean area, but it contributes significantly to the global carbon cycle. Recent observations of seawater CO2-carbonate chemistry in shelf waters of the western Arctic Ocean, primarily in the Chukchi Sea, from 2009 to 2011 indicate that bottom waters are seasonally undersaturated with respect to calcium carbonate (CaCO3) minerals, particularly aragonite. Nearly 40% of sampled bottom waters on the shelf have saturation states...

  18. Pan-Arctic Distribution of Bioavailable Dissolved Organic Matter and Linkages With Productivity in Ocean Margins

    Science.gov (United States)

    Shen, Yuan; Benner, Ronald; Kaiser, Karl; Fichot, Cédric G.; Whitledge, Terry E.

    2018-02-01

    Rapid environmental changes in the Arctic Ocean affect plankton productivity and the bioavailability of dissolved organic matter (DOM) that supports microbial food webs. We report concentrations of dissolved organic carbon (DOC) and yields of amino acids (indicators of labile DOM) in surface waters across major Arctic margins. Concentrations of DOC and bioavailability of DOM showed large pan-Arctic variability that corresponded to varying hydrological conditions and ecosystem productivity, respectively. Widespread hot spots of labile DOM were observed over productive inflow shelves (Chukchi and Barents Seas), in contrast to oligotrophic interior margins (Kara, Laptev, East Siberian, and Beaufort Seas). Amino acid yields in outflow gateways (Canadian Archipelago and Baffin Bay) indicated the prevalence of semilabile DOM in sea ice covered regions and sporadic production of labile DOM in ice-free waters. Comparing these observations with surface circulation patterns indicated varying shelf subsidies of bioavailable DOM to Arctic deep basins.

  19. A 4.5 km resolution Arctic Ocean simulation with the global multi-resolution model FESOM 1.4

    Science.gov (United States)

    Wang, Qiang; Wekerle, Claudia; Danilov, Sergey; Wang, Xuezhu; Jung, Thomas

    2018-04-01

    In the framework of developing a global modeling system which can facilitate modeling studies on Arctic Ocean and high- to midlatitude linkage, we evaluate the Arctic Ocean simulated by the multi-resolution Finite Element Sea ice-Ocean Model (FESOM). To explore the value of using high horizontal resolution for Arctic Ocean modeling, we use two global meshes differing in the horizontal resolution only in the Arctic Ocean (24 km vs. 4.5 km). The high resolution significantly improves the model's representation of the Arctic Ocean. The most pronounced improvement is in the Arctic intermediate layer, in terms of both Atlantic Water (AW) mean state and variability. The deepening and thickening bias of the AW layer, a common issue found in coarse-resolution simulations, is significantly alleviated by using higher resolution. The topographic steering of the AW is stronger and the seasonal and interannual temperature variability along the ocean bottom topography is enhanced in the high-resolution simulation. The high resolution also improves the ocean surface circulation, mainly through a better representation of the narrow straits in the Canadian Arctic Archipelago (CAA). The representation of CAA throughflow not only influences the release of water masses through the other gateways but also the circulation pathways inside the Arctic Ocean. However, the mean state and variability of Arctic freshwater content and the variability of freshwater transport through the Arctic gateways appear not to be very sensitive to the increase in resolution employed here. By highlighting the issues that are independent of model resolution, we address that other efforts including the improvement of parameterizations are still required.

  20. Temperature dependence of CO2-enhanced primary production in the European Arctic Ocean

    KAUST Repository

    Holding, J. M.; Duarte, Carlos M.; Sanz-Martí n, M.; Mesa, E.; Arrieta, J M; Chierici, M.; Hendriks, I.  E.; Garcí a-Corral, L. S.; Regaudie-de-Gioux, A.; Delgado, A.; Reigstad, M.; Wassmann, P.; Agusti, Susana

    2015-01-01

    production (GPP) may be temperature dependent, using data from several oceanographic cruises and experiments from both spring and summer in the European sector of the Arctic Ocean. Results confirm that CO2 enhances GPP (by a factor of up to ten) over a range

  1. Photosynthetic production in the central Arctic Ocean during the record sea-ice minimum in 2012

    NARCIS (Netherlands)

    Fernández-Méndez, M.; Katlein, C.; Rabe, B.; Nicolaus, M.; Peeken, I.; Bakker, K.; Flores, H.; Boetius, A.

    2015-01-01

    The ice-covered central Arctic Ocean is characterized by low primary productivity due to light and nutrient limitations. The recent reduction in ice cover has the potential to substantially increase phytoplankton primary production, but little is yet known about the fate of the ice-associated

  2. Origin of freshwater and polynya water in the Arctic Ocean halocline in summer 2007

    NARCIS (Netherlands)

    Bauch, D.; Rutgers van der Loeff, M.; Andersen, N.; Torres-Valdes, S.; Bakker, K.; Abrahamsen, E.Povl

    2011-01-01

    Extremely low summer sea-ice coverage in the Arctic Ocean in 2007 allowed extensive sampling and a wide quasi-synoptic hydrographic and delta O-18 dataset could be collected in the Eurasian Basin and the Makarov Basin up to the Alpha Ridge and the East Siberian continental margin. With the aim of

  3. Modelling micro- and macrophysical contributors to the dissipation of an Arctic mixed-phase cloud during the Arctic Summer Cloud Ocean Study (ASCOS

    Directory of Open Access Journals (Sweden)

    K. Loewe

    2017-06-01

    Full Text Available The Arctic climate is changing; temperature changes in the Arctic are greater than at midlatitudes, and changing atmospheric conditions influence Arctic mixed-phase clouds, which are important for the Arctic surface energy budget. These low-level clouds are frequently observed across the Arctic. They impact the turbulent and radiative heating of the open water, snow, and sea-ice-covered surfaces and influence the boundary layer structure. Therefore the processes that affect mixed-phase cloud life cycles are extremely important, yet relatively poorly understood. In this study, we present sensitivity studies using semi-idealized large eddy simulations (LESs to identify processes contributing to the dissipation of Arctic mixed-phase clouds. We found that one potential main contributor to the dissipation of an observed Arctic mixed-phase cloud, during the Arctic Summer Cloud Ocean Study (ASCOS field campaign, was a low cloud droplet number concentration (CDNC of about 2 cm−3. Introducing a high ice crystal concentration of 10 L−1 also resulted in cloud dissipation, but such high ice crystal concentrations were deemed unlikely for the present case. Sensitivity studies simulating the advection of dry air above the boundary layer inversion, as well as a modest increase in ice crystal concentration of 1 L−1, did not lead to cloud dissipation. As a requirement for small droplet numbers, pristine aerosol conditions in the Arctic environment are therefore considered an important factor determining the lifetime of Arctic mixed-phase clouds.

  4. Sensitivity of the Arctic Ocean gas hydrate to climate changes in the period of 1948-2015

    Science.gov (United States)

    Malakhova, Valentina V.; Golubeva, Elena N.; Iakshina, Dina F.

    2017-11-01

    The objective of the present study is to analyze the interactions between a methane hydrates stability zone and the ocean temperature variations and to define the hydrate sensitivity to the contemporary warming in the Arctic Ocean. To obtain the spatial-temporary variability of the ocean bottom temperature we employ the ICMMG regional Arctic-North Atlantic ocean model that has been developed in the Institute of Computational Mathematics and Mathematical Geophysics. With the ice-ocean model the Arctic bottom water temperatures were analyzed. The resulting warming ocean bottom water is spatially inhomogeneous, with a strong impact by the Atlantic inflow on shallow regions of 200-500 m depth. Results of the mathematical modeling of the dynamics of methane hydrate stability zone in the Arctic Ocean sediment are reported. We find that the reduction of the methane hydrate stability zone occurs in the Arctic Ocean between 250 and 400 m water depths within the upper 100 m of sediment in the area influenced by the Atlantic inflow. We have identified the areas of the Arctic Ocean where an increase in methane release is probable to occur at the present time.

  5. An atmosphere-ocean GCM modelling study of the climate response to changing Arctic seaways in the early Cenozoic.

    Science.gov (United States)

    Roberts, C. D.; Legrande, A. N.; Tripati, A. K.

    2008-12-01

    The report of fossil Azolla (a freshwater aquatic fern) in sediments from the Lomonosov Ridge suggests low salinity conditions occurred in the Arctic Ocean in the early Eocene. Restricted passages between the Arctic Ocean and the surrounding oceans are hypothesized to have caused this Arctic freshening. We investigate this scenario using a water-isotope enabled atmosphere-ocean general circulation model with Eocene boundary conditions including 4xCO2, 7xCH4, altered bathymetry and topography, and an estimated distribution of Eocene vegetational types. In one experiment, oceanic exchange between the Arctic Ocean and other ocean basins was restricted to two shallow (~250 m) seaways, one in the North Atlantic, the Greenland-Norwegian seaway, and the second connecting the Arctic Ocean with the Tethys Ocean, the Turgai Straits. In the restricted configuration, the Greenland-Norwegian seaway was closed and exchange through the Turgai Straits was limited to a depth of ~60 m. The simulations suggest that the severe restriction of Arctic seaways in the early Eocene may have been sufficient to freshen Arctic Ocean surface waters, conducive to Azolla blooms. When exchange with the Arctic Ocean is limited, salinities in the upper several hundred meters of the water column decrease by ~10 psu. In some regions, surface salinity is within 2-3 psu of the reported maximum modern conditions tolerated by Azolla (~5 psu). In the restricted scenario, salt is stored preferentially in the North Atlantic and Tethys oceans, resulting in enhanced meridional overturning, increased poleward heat transport in the North Atlantic western boundary current, and warming of surface and intermediate waters in the North Atlantic by several degrees. Increased sensible and latent heat fluxes from the North Atlantic Ocean, combined with a reduction in cloud albedo, also lead to an increase in surface air temperature of over much of North America, Greenland and Eurasia. Our work is consistent with

  6. Remote sensing estimation of terrestrially derived colored dissolved organic matterinput to the Arctic Ocean

    Science.gov (United States)

    Li, J.; Yu, Q.; Tian, Y. Q.

    2017-12-01

    The DOC flux from land to the Arctic Ocean has remarkable implication on the carbon cycle, biogeochemical & ecological processes in the Arctic. This lateral carbon flux is required to be monitored with high spatial & temporal resolution. However, the current studies in the Arctic regions were obstructed by the factors of the low spatial coverages. The remote sensing could provide an alternative bio-optical approach to field sampling for DOC dynamics monitoring through the observation of the colored dissolved organic matter (CDOM). The DOC and CDOM were found highly correlated based on the analysis of the field sampling data from the Arctic-GRO. These provide the solid foundation of the remote sensing observation. In this study, six major Arctic Rivers (Yukon, Kolyma, Lena, Mackenzie, Ob', Yenisey) were selected to derive the CDOM dynamics along four years. Our newly developed SBOP algorithm was applied to the large Landsat-8 OLI image data (nearly 100 images) for getting the high spatial resolution results. The SBOP algorithm is the first approach developing for the Shallow Water Bio-optical properties estimation. The CDOM absorption derived from the satellite images were verified with the field sampling results with high accuracy (R2 = 0.87). The distinct CDOM dynamics were found in different Rivers. The CDOM absorptions were found highly related to the hydrological activities and the terrestrially environmental dynamics. Our study helps to build the reliable system for studying the carbon cycle at Arctic regions.

  7. History of sea ice in the Arctic

    DEFF Research Database (Denmark)

    Polyak, Leonid; Alley, Richard B.; Andrews, John T.

    2010-01-01

    Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of Arctic sea-ice conditions through the geologic past. This inf......Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of Arctic sea-ice conditions through the geologic past...... Optimum, and consistently covered at least part of the Arctic Ocean for no less than the last 13–14 million years. Ice was apparently most widespread during the last 2–3 million years, in accordance with Earth’s overall cooler climate. Nevertheless, episodes of considerably reduced sea ice or even...

  8. {sup 236}U and {sup 129}I as tracers of water masses in the Arctic Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Casacuberta, Nuria; Christl, Marcus; Vockenhuber, Christof; Synal, Hans-Arno [Laboratory of Ion Beam Physics, ETH-Zurich (Switzerland); Walther, Clemens [Institut fuer Radiooekologie und Strahlenschutz, Leibniz Universitaet Hannover (Germany); Loeff, Michiel van der [AWI-Geochemistry, Alfred Wegener Institut Fuer Polar und Meeresforshung, Bremerhaven (Germany); Masque, Pere [Institut de Ciencia i Tecnologia Ambientals, Universitat Autonoma de Barcelona, Bellaterra (Spain)

    2014-07-01

    Recently {sup 236}U attested to be a new transient oceanographic tracer: it is conservative in seawater and far from having reached steady state in the oceans. Its main sources in the North Atlantic are global fallout and European reprocessing plants. In this study, concentrations of {sup 236}U and {sup 129}I of eight deep profiles in the Arctic Ocean collected in 2011-2012 were determined with a compact ETH Zurich AMS system (TANDY). Results on {sup 236}U/{sup 238}U show a steep gradient, from the lowest ever-reported {sup 236}U/{sup 238}U atomic ratio in open ocean water (5±5) x 10{sup -12} up to (3700±80) x 10{sup -12}. Whereas the very low ratios are indicative for deep old waters, high ratios in shallow and surface waters show a clear signature of Atlantic Waters (AW) penetrating to the Arctic Ocean. The combination of {sup 236}U with {sup 129}I, both being released by the nuclear reprocessing plants of Sellafield and La Hague, with a distinct temporal input function, is used to estimate transit time of AW distributions in the Arctic Ocean.

  9. Assessing the added value of the recent declaration on unregulated fishing for sustainable governance of the central Arctic Ocean

    DEFF Research Database (Denmark)

    Shephard, Grace Elizabeth; Dalen, Kari; Peldszus, Regina

    2016-01-01

    The ‘Declaration concerning the prevention of unregulated high seas fishing in the central Arctic Ocean’ signed by the Arctic 5 nations, limits unregulated high seas fishing in the central part of the Arctic Ocean, and holds potential social, economic and political impacts for numerous stakeholders....... In this paper, the four Interim Measures in the Declaration are discussed and what value these measures bring beyond the existing international agreements is explored. It is found that even though the Declaration fills a gap in the management of potential fish stocks in the central Arctic Ocean, adopts...... understanding of the fisheries as well as the broader Arctic environment. Furthermore, the research generated by this measure will provide an important decision base for both regulation and management of human activity in the Arctic....

  10. A modelling study of the influence of anomalous wind forcing over the Barents Sea on the Atlantic water flow to the Arctic Ocean in the period 1979-2004

    Science.gov (United States)

    Marciniak, Jakub; Schlichtholz, Pawel; Maslowski, Wieslaw

    2016-04-01

    Arctic climate system is influenced by oceanic heat transport with the Atlantic water (AW) streaming towards the Arctic Ocean in two branches, through the deep Fram Strait and the shallow Barents Sea. In Fram Strait, the AW submerges below the Polar surface water and then flows cyclonically along the margin of the Arctic Ocean as a subsurface water mass in the Arctic Slope Current. In contrast to the Fram Strait branch, which is the major source of heat for the Arctic Ocean, most of the heat influx to the Barents Sea through the Barents Sea opening (BSO) is passed to the atmosphere. Only cold remnants of AW outflow to the Arctic Ocean through the northeastern gate of the Barents Sea. Some AW entering the Barents Sea recirculates westward, contributing to an outflow from the Barents Sea through the BSO along the shelf slope south of Bear Island, in the Bear Island Slope Current. Even though the two-branched AW flow toward the Arctic Ocean has been known for more than a century, little is known about co-variability of heat fluxes in the two branches, its mechanisms and climatic implications. Recent studies indicate that the Bear Island Slope Current may play a role in this co-variability. Here, co-variability of the flow through the BSO and Fram Strait is investigated using a pan-Arctic coupled ice-ocean hindcast model run for the period 1979-2004 and forced with daily atmospheric data from the ECMWF. Significant wintertime co-variability between the volume transport in the Bear Island and Arctic slope currents and its link to wind forcing over the Barents Sea is confirmed. It is found that the volume transports in these currents are, however, not correlated in the annual mean and that the wintertime co-variability of these currents has no immediate effect on either the net heat flux through the BSO or the net heat flux divergence in the Barents Sea. It is shown that the main climatic effect of wind forcing over the northern Barents Sea shelf is to induce temperature

  11. High variability of atmospheric mercury in the summertime boundary layer through the central Arctic Ocean.

    Science.gov (United States)

    Yu, Juan; Xie, Zhouqing; Kang, Hui; Li, Zheng; Sun, Chen; Bian, Lingen; Zhang, Pengfei

    2014-08-15

    The biogeochemical cycles of mercury in the Arctic springtime have been intensively investigated due to mercury being rapidly removed from the atmosphere. However, the behavior of mercury in the Arctic summertime is still poorly understood. Here we report the characteristics of total gaseous mercury (TGM) concentrations through the central Arctic Ocean from July to September, 2012. The TGM concentrations varied considerably (from 0.15 ng/m(3) to 4.58 ng/m(3)), and displayed a normal distribution with an average of 1.23 ± 0.61 ng/m(3). The highest frequency range was 1.0-1.5 ng/m(3), lower than previously reported background values in the Northern Hemisphere. Inhomogeneous distributions were observed over the Arctic Ocean due to the effect of sea ice melt and/or runoff. A lower level of TGM was found in July than in September, potentially because ocean emission was outweighed by chemical loss.

  12. Two regimes of the Arctic's circulation from ocean models with ice and contaminants.

    Science.gov (United States)

    Proshutinsky, A Y; Johnson, M

    2001-01-01

    A two-dimensional barotropic, coupled, ocean-ice model with a space resolution of 55.5 km and driven by atmospheric forces, river run-off, and sea-level slope between the Pacific and the Arctic Oceans, has been used to simulate the vertically averaged currents and ice drift in the Arctic Ocean. Results from 43 years of numerical simulations of water and ice motions demonstrate that two wind-driven circulation regimes are possible in the Arctic, a cyclonic and an anti-cyclonic circulation. These two regimes appear to alternate at 5-7 year intervals with the 10-15 year period. It is important to pollution studies to understand which circulation regime prevails at any time. It is anticipated that 1995 is a year with a cyclonic regime, and during this cyclonic phase and possibly during past cyclonic regimes as well, pollutants may reach the Alaskan shelf. The regime shifts demonstrated in this paper are fundamentally important to understanding the Arctic's general circulation and particularly important for estimating pollution transport.

  13. Vulnerability of Polar Oceans to Anthropogenic Acidification: Comparison of Arctic and Antarctic Seasonal Cycles

    OpenAIRE

    E. H. Shadwick; T. W. Trull; H. Thomas; J. A. E. Gibson

    2013-01-01

    Polar oceans are chemically sensitive to anthropogenic acidification due to their relatively low alkalinity and correspondingly weak carbonate buffering capacity. Here, we compare unique CO2 system observations covering complete annual cycles at an Arctic (Amundsen Gulf) and Antarctic site (Prydz Bay). The Arctic site experiences greater seasonal warming (10 vs 3?C), and freshening (3 vs 2), has lower alkalinity (2220 vs 2320??mol/kg), and lower summer pH (8.15 vs 8.5), than the Antarctic sit...

  14. TOPAZ4: an ocean-sea ice data assimilation system for the North Atlantic and Arctic

    Directory of Open Access Journals (Sweden)

    P. Sakov

    2012-08-01

    Full Text Available We present a detailed description of TOPAZ4, the latest version of TOPAZ – a coupled ocean-sea ice data assimilation system for the North Atlantic Ocean and Arctic. It is the only operational, large-scale ocean data assimilation system that uses the ensemble Kalman filter. This means that TOPAZ features a time-evolving, state-dependent estimate of the state error covariance. Based on results from the pilot MyOcean reanalysis for 2003–2008, we demonstrate that TOPAZ4 produces a realistic estimate of the ocean circulation in the North Atlantic and the sea-ice variability in the Arctic. We find that the ensemble spread for temperature and sea-level remains fairly constant throughout the reanalysis demonstrating that the data assimilation system is robust to ensemble collapse. Moreover, the ensemble spread for ice concentration is well correlated with the actual errors. This indicates that the ensemble statistics provide reliable state-dependent error estimates – a feature that is unique to ensemble-based data assimilation systems. We demonstrate that the quality of the reanalysis changes when different sea surface temperature products are assimilated, or when in-situ profiles below the ice in the Arctic Ocean are assimilated. We find that data assimilation improves the match to independent observations compared to a free model. Improvements are particularly noticeable for ice thickness, salinity in the Arctic, and temperature in the Fram Strait, but not for transport estimates or underwater temperature. At the same time, the pilot reanalysis has revealed several flaws in the system that have degraded its performance. Finally, we show that a simple bias estimation scheme can effectively detect the seasonal or constant bias in temperature and sea-level.

  15. Anthropogenic radioactivity in the Arctic Ocean. Review of the results from the joint German project

    International Nuclear Information System (INIS)

    Nies, H.; Harms, I.H.; Karcher, M.J.; Dethleff, D.; Bahe, C.

    1999-01-01

    The paper presents the results of the joint project carried out in Germany in order to assess the consequences in the marine environment from the dumping of nuclear wastes in the Kara and Barents Seas. The project consisted of experimental work on measurements of radionuclides in samples from the Arctic marine environment and numerical modelling of the potential pathways and dispersion of contaminants in the Arctic Ocean. Water and sediment samples were collected for determination of radionuclide such as 137Cs, 90Sr, 239+240Pu, 238Pu, and 241Am and various organic micropollutants. In addition, a few water and numerous surface sediment samples collected in the Kara Sea and from the Kola peninsula were taken by Russian colleagues and analysed for artificial radionuclides by the BSH laboratory. The role of transport by sea ice from the Kara Sea into the Arctic Ocean was assessed by a small subgroup at GEOMAR. This transport process might be considered as a rapid contribution due to entrainment of contaminated sediments into sea ice, following export from the Kara Sea into the transpolar ice drift and subsequent release in the Atlantic Ocean in the area of the East Greenland Current. Numerical modelling of dispersion of pollutants from the Kara and Barents Seas was carried out both on a local scale for the Barents and Kara Seas and for long range dispersion into the Arctic and Atlantic Oceans. Three-dimensional baroclinic circulation models were applied to trace the transport of pollutants. Experimental results were used to validate the model results such as the discharges from the nuclear reprocessing plant at Sellafield and subsequent contamination of the North Sea up the Arctic Seas

  16. Anthropogenic radioactivity in the Arctic Ocean--review of the results from the joint German project.

    Science.gov (United States)

    Nies, H; Harms, I H; Karcher, M J; Dethleff, D; Bahe, C

    1999-09-30

    The paper presents the results of the joint project carried out in Germany in order to assess the consequences in the marine environment from the dumping of nuclear wastes in the Kara and Barents Seas. The project consisted of experimental work on measurements of radionuclides in samples from the Arctic marine environment and numerical modelling of the potential pathways and dispersion of contaminants in the Arctic Ocean. Water and sediment samples were collected for determination of radionuclide such as 137Cs, 90Sr, 239 + 240Pu, 238Pu, and 241Am and various organic micropollutants. In addition, a few water and numerous surface sediment samples collected in the Kara Sea and from the Kola peninsula were taken by Russian colleagues and analysed for artificial radionuclide by the BSH laboratory. The role of transport by sea ice from the Kara Sea into the Arctic Ocean was assessed by a small subgroup at GEOMAR. This transport process might be considered as a rapid contribution due to entrainment of contaminated sediments into sea ice, following export from the Kara Sea into the transpolar ice drift and subsequent release in the Atlantic Ocean in the area of the East Greenland Current. Numerical modelling of dispersion of pollutants from the Kara and Barents Seas was carried out both on a local scale for the Barents and Kara Seas and for long range dispersion into the Arctic and Atlantic Oceans. Three-dimensional baroclinic circulation models were applied to trace the transport of pollutants. Experimental results were used to validate the model results such as the discharges from the nuclear reprocessing plant at Sellafield and subsequent contamination of the North Sea up the Arctic Seas.

  17. Toward Improved Estimation of the Dynamic Topography and Ocean Circulation in the High Latitude and Arctic Ocean: The Importance of GOCE

    DEFF Research Database (Denmark)

    Johannessen, J. A.; Raj, R. P.; Nilsen, J. E. Ø.

    2014-01-01

    The Arctic plays a fundamental role in the climate system and shows significant sensitivity to anthropogenic climate forcing and the ongoing climate change. Accelerated changes in the Arctic are already observed, including elevated air and ocean temperatures, declines of the summer sea ice extent...... quantify this. Moreover, changes in the temperature and salinity of surface waters in the Arctic Ocean and Nordic Seas may also influence the flow of dense water through the Denmark Strait, which are found to be a precursor for changes in the Atlantic meridional overturning circulation with a lead time...... circulation and transport variability in the high latitude and Arctic Ocean. In this respect, this study combines in situ hydrographical data, surface drifter data and direct current meter measurements, with coupled sea ice–ocean models, radar altimeter data and the latest GOCE-based geoid in order...

  18. Optical Characterisation of Suspended Particles in the Mackenzie River Plume (Canadian Arctic Ocean) and Implications for Ocean Colour Remote Sensing

    Science.gov (United States)

    Doxaran, D.; Ehn, J.; Belanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

    2012-01-01

    Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future

  19. High colored dissolved organic matter (CDOM) absorption in surface waters of the central-eastern Arctic Ocean: Implications for biogeochemistry and ocean color algorithms.

    Science.gov (United States)

    Gonçalves-Araujo, Rafael; Rabe, Benjamin; Peeken, Ilka; Bracher, Astrid

    2018-01-01

    As consequences of global warming sea-ice shrinking, permafrost thawing and changes in fresh water and terrestrial material export have already been reported in the Arctic environment. These processes impact light penetration and primary production. To reach a better understanding of the current status and to provide accurate forecasts Arctic biogeochemical and physical parameters need to be extensively monitored. In this sense, bio-optical properties are useful to be measured due to the applicability of optical instrumentation to autonomous platforms, including satellites. This study characterizes the non-water absorbers and their coupling to hydrographic conditions in the poorly sampled surface waters of the central and eastern Arctic Ocean. Over the entire sampled area colored dissolved organic matter (CDOM) dominates the light absorption in surface waters. The distribution of CDOM, phytoplankton and non-algal particles absorption reproduces the hydrographic variability in this region of the Arctic Ocean which suggests a subdivision into five major bio-optical provinces: Laptev Sea Shelf, Laptev Sea, Central Arctic/Transpolar Drift, Beaufort Gyre and Eurasian/Nansen Basin. Evaluating ocean color algorithms commonly applied in the Arctic Ocean shows that global and regionally tuned empirical algorithms provide poor chlorophyll-a (Chl-a) estimates. The semi-analytical algorithms Generalized Inherent Optical Property model (GIOP) and Garver-Siegel-Maritorena (GSM), on the other hand, provide robust estimates of Chl-a and absorption of colored matter. Applying GSM with modifications proposed for the western Arctic Ocean produced reliable information on the absorption by colored matter, and specifically by CDOM. These findings highlight that only semi-analytical ocean color algorithms are able to identify with low uncertainty the distribution of the different optical water constituents in these high CDOM absorbing waters. In addition, a clustering of the Arctic Ocean

  20. Late Cenozoic Arctic Ocean sea ice and terrestrial paleoclimate.

    Science.gov (United States)

    Carter, L.D.; Brigham-Grette, J.; Marincovich, L.; Pease, V.L.; Hillhouse, J.W.

    1986-01-01

    Sea otter remains found in deposits of two marine transgressions (Bigbendian and Fishcreekian) of the Alaskan Arctic Coastal Plain which occurred between 2.4 and 3 Ma suggest that during these two events the southern limit of seasonal sea ice was at least 1600 km farther north than at present in Alaskan waters. Perennial sea ice must have been severely restricted or absent, and winters were warmer than at present during these two sea-level highstands. Paleomagnetic, faunal, and palynological data indicate that the later transgression (Fishcreekian) occurred during the early part of the Matuyama Reversed-Polarity Chron. -from Authors

  1. Patterns and trends of macrobenthic abundance, biomass and production in the deep Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Renate Degen

    2015-08-01

    Full Text Available Little is known about the distribution and dynamics of macrobenthic communities of the deep Arctic Ocean. The few previous studies report low standing stocks and confirm a gradient with declining biomass from the slopes down to the basins, as commonly reported for deep-sea benthos. In this study, we investigated regional differences of faunal abundance and biomass, and made for the first time ever estimates of deep Arctic community production by using a multi-parameter artificial neural network model. The underlying data set combines data from recent field studies with published and unpublished data from the past 20 years, to analyse the influence of water depth, geographical latitude and sea-ice concentration on Arctic benthic communities. We were able to confirm the previously described negative relationship of macrofauna standing stock with water depth in the Arctic deep sea, while also detecting substantial regional differences. Furthermore, abundance, biomass and production decreased significantly with increasing sea-ice extent (towards higher latitudes down to values <200 ind m−2, <65 mg C m−2 and <73 mg C m−2 y−1, respectively. In contrast, stations under the seasonal ice zone regime showed much higher standing stock and production (up to 2500 mg C m−2 y−1, even at depths down to 3700 m. We conclude that particle flux is the key factor structuring benthic communities in the deep Arctic Ocean as it explains both the low values in the ice-covered Arctic basins and the higher values in the seasonal ice zone.

  2. Continental Margins of the Arctic Ocean: Implications for Law of the Sea

    Science.gov (United States)

    Mosher, David

    2016-04-01

    A coastal State must define the outer edge of its continental margin in order to be entitled to extend the outer limits of its continental shelf beyond 200 M, according to article 76 of the UN Convention on the Law of the Sea. The article prescribes the methods with which to make this definition and includes such metrics as water depth, seafloor gradient and thickness of sediment. Note the distinction between the "outer edge of the continental margin", which is the extent of the margin after application of the formula of article 76, and the "outer limit of the continental shelf", which is the limit after constraint criteria of article 76 are applied. For a relatively small ocean basin, the Arctic Ocean reveals a plethora of continental margin types reflecting both its complex tectonic origins and its diverse sedimentation history. These factors play important roles in determining the extended continental shelves of Arctic coastal States. This study highlights the critical factors that might determine the outer edge of continental margins in the Arctic Ocean as prescribed by article 76. Norway is the only Arctic coastal State that has had recommendations rendered by the Commission on the Limits of the Continental Shelf (CLCS). Russia and Denmark (Greenland) have made submissions to the CLCS to support their extended continental shelves in the Arctic and are awaiting recommendations. Canada has yet to make its submission and the US has not yet ratified the Convention. The various criteria that each coastal State has utilized or potentially can utilize to determine the outer edge of the continental margin are considered. Important criteria in the Arctic include, 1) morphological continuity of undersea features, such as the various ridges and spurs, with the landmass, 2) the tectonic origins and geologic affinities with the adjacent land masses of the margins and various ridges, 3) sedimentary processes, particularly along continental slopes, and 4) thickness and

  3. Ice and ocean velocity in the Arctic marginal ice zone: Ice roughness and momentum transfer

    Directory of Open Access Journals (Sweden)

    Sylvia T. Cole

    2017-09-01

    Full Text Available The interplay between sea ice concentration, sea ice roughness, ocean stratification, and momentum transfer to the ice and ocean is subject to seasonal and decadal variations that are crucial to understanding the present and future air-ice-ocean system in the Arctic. In this study, continuous observations in the Canada Basin from March through December 2014 were used to investigate spatial differences and temporal changes in under-ice roughness and momentum transfer as the ice cover evolved seasonally. Observations of wind, ice, and ocean properties from four clusters of drifting instrument systems were complemented by direct drill-hole measurements and instrumented overhead flights by NASA operation IceBridge in March, as well as satellite remote sensing imagery about the instrument clusters. Spatially, directly estimated ice-ocean drag coefficients varied by a factor of three with rougher ice associated with smaller multi-year ice floe sizes embedded within the first-year-ice/multi-year-ice conglomerate. Temporal differences in the ice-ocean drag coefficient of 20–30% were observed prior to the mixed layer shoaling in summer and were associated with ice concentrations falling below 100%. The ice-ocean drag coefficient parameterization was found to be invalid in September with low ice concentrations and small ice floe sizes. Maximum momentum transfer to the ice occurred for moderate ice concentrations, and transfer to the ocean for the lowest ice concentrations and shallowest stratification. Wind work and ocean work on the ice were the dominant terms in the kinetic energy budget of the ice throughout the melt season, consistent with free drift conditions. Overall, ice topography, ice concentration, and the shallow summer mixed layer all influenced mixed layer currents and the transfer of momentum within the air-ice-ocean system. The observed changes in momentum transfer show that care must be taken to determine appropriate parameterizations

  4. Aerosol indirect effects on the nighttime Arctic Ocean surface from thin, predominantly liquid clouds

    Directory of Open Access Journals (Sweden)

    L. M. Zamora

    2017-06-01

    Full Text Available Aerosol indirect effects have potentially large impacts on the Arctic Ocean surface energy budget, but model estimates of regional-scale aerosol indirect effects are highly uncertain and poorly validated by observations. Here we demonstrate a new way to quantitatively estimate aerosol indirect effects on a regional scale from remote sensing observations. In this study, we focus on nighttime, optically thin, predominantly liquid clouds. The method is based on differences in cloud physical and microphysical characteristics in carefully selected clean, average, and aerosol-impacted conditions. The cloud subset of focus covers just ∼ 5 % of cloudy Arctic Ocean regions, warming the Arctic Ocean surface by ∼ 1–1.4 W m−2 regionally during polar night. However, within this cloud subset, aerosol and cloud conditions can be determined with high confidence using CALIPSO and CloudSat data and model output. This cloud subset is generally susceptible to aerosols, with a polar nighttime estimated maximum regionally integrated indirect cooling effect of ∼ −0.11 W m−2 at the Arctic sea ice surface (∼ 8 % of the clean background cloud effect, excluding cloud fraction changes. Aerosol presence is related to reduced precipitation, cloud thickness, and radar reflectivity, and in some cases, an increased likelihood of cloud presence in the liquid phase. These observations are inconsistent with a glaciation indirect effect and are consistent with either a deactivation effect or less-efficient secondary ice formation related to smaller liquid cloud droplets. However, this cloud subset shows large differences in surface and meteorological forcing in shallow and higher-altitude clouds and between sea ice and open-ocean regions. For example, optically thin, predominantly liquid clouds are much more likely to overlay another cloud over the open ocean, which may reduce aerosol indirect effects on the surface. Also, shallow clouds over

  5. Arctic surface temperatures from Metop AVHRR compared to in situ ocean and land data

    Directory of Open Access Journals (Sweden)

    G. Dybkjær

    2012-11-01

    Full Text Available The ice surface temperature (IST is an important boundary condition for both atmospheric and ocean and sea ice models and for coupled systems. An operational ice surface temperature product using satellite Metop AVHRR infra-red data was developed for MyOcean. The IST can be mapped in clear sky regions using a split window algorithm specially tuned for sea ice. Clear sky conditions prevail during spring in the Arctic, while persistent cloud cover limits data coverage during summer. The cloud covered regions are detected using the EUMETSAT cloud mask. The Metop IST compares to 2 m temperature at the Greenland ice cap Summit within STD error of 3.14 °C and to Arctic drifting buoy temperature data within STD error of 3.69 °C. A case study reveals that the in situ radiometer data versus satellite IST STD error can be much lower (0.73 °C and that the different in situ measurements complicate the validation. Differences and variability between Metop IST and in situ data are analysed and discussed. An inter-comparison of Metop IST, numerical weather prediction temperatures and in situ observation indicates large biases between the different quantities. Because of the scarcity of conventional surface temperature or surface air temperature data in the Arctic, the satellite IST data with its relatively good coverage can potentially add valuable information to model analysis for the Arctic atmosphere.

  6. Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

    Science.gov (United States)

    Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert; Babb, David G.; Toudal Pedersen, Leif; Rysgaard, Søren; Kristoffersen, Yngve; Barber, David G.

    2017-12-01

    The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature-salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean-glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

  7. Levoglucosan indicates high levels of biomass burning aerosols over oceans from the Arctic to Antarctic.

    Science.gov (United States)

    Hu, Qi-Hou; Xie, Zhou-Qing; Wang, Xin-Ming; Kang, Hui; Zhang, Pengfei

    2013-11-01

    Biomass burning is known to affect air quality, global carbon cycle, and climate. However, the extent to which biomass burning gases/aerosols are present on a global scale, especially in the marine atmosphere, is poorly understood. Here we report the molecular tracer levoglucosan concentrations in marine air from the Arctic Ocean through the North and South Pacific Ocean to Antarctica during burning season. Levoglucosan was found to be present in all regions at ng/m(3) levels with the highest atmospheric loadings present in the mid-latitudes (30°-60° N and S), intermediate loadings in the Arctic, and lowest loadings in the Antarctic and equatorial latitudes. As a whole, levoglucosan concentrations in the Southern Hemisphere were comparable to those in the Northern Hemisphere. Biomass burning has a significant impact on atmospheric Hg and water-soluble organic carbon (WSOC) from pole-to-pole, with more contribution to WSOC in the Northern Hemisphere than in the Southern Hemisphere.

  8. The Arctic Summer Cloud Ocean Study (ASCOS): overview and experimental design

    Science.gov (United States)

    Tjernström, M.; Leck, C.; Birch, C. E.; Bottenheim, J. W.; Brooks, B. J.; Brooks, I. M.; Bäcklin, L.; Chang, R. Y.-W.; de Leeuw, G.; Di Liberto, L.; de la Rosa, S.; Granath, E.; Graus, M.; Hansel, A.; Heintzenberg, J.; Held, A.; Hind, A.; Johnston, P.; Knulst, J.; Martin, M.; Matrai, P. A.; Mauritsen, T.; Müller, M.; Norris, S. J.; Orellana, M. V.; Orsini, D. A.; Paatero, J.; Persson, P. O. G.; Gao, Q.; Rauschenberg, C.; Ristovski, Z.; Sedlar, J.; Shupe, M. D.; Sierau, B.; Sirevaag, A.; Sjogren, S.; Stetzer, O.; Swietlicki, E.; Szczodrak, M.; Vaattovaara, P.; Wahlberg, N.; Westberg, M.; Wheeler, C. R.

    2014-03-01

    The climate in the Arctic is changing faster than anywhere else on earth. Poorly understood feedback processes relating to Arctic clouds and aerosol-cloud interactions contribute to a poor understanding of the present changes in the Arctic climate system, and also to a large spread in projections of future climate in the Arctic. The problem is exacerbated by the paucity of research-quality observations in the central Arctic. Improved formulations in climate models require such observations, which can only come from measurements in situ in this difficult-to-reach region with logistically demanding environmental conditions. The Arctic Summer Cloud Ocean Study (ASCOS) was the most extensive central Arctic Ocean expedition with an atmospheric focus during the International Polar Year (IPY) 2007-2008. ASCOS focused on the study of the formation and life cycle of low-level Arctic clouds. ASCOS departed from Longyearbyen on Svalbard on 2 August and returned on 9 September 2008. In transit into and out of the pack ice, four short research stations were undertaken in the Fram Strait: two in open water and two in the marginal ice zone. After traversing the pack ice northward, an ice camp was set up on 12 August at 87°21' N, 01°29' W and remained in operation through 1 September, drifting with the ice. During this time, extensive measurements were taken of atmospheric gas and particle chemistry and physics, mesoscale and boundary-layer meteorology, marine biology and chemistry, and upper ocean physics. ASCOS provides a unique interdisciplinary data set for development and testing of new hypotheses on cloud processes, their interactions with the sea ice and ocean and associated physical, chemical, and biological processes and interactions. For example, the first-ever quantitative observation of bubbles in Arctic leads, combined with the unique discovery of marine organic material, polymer gels with an origin in the ocean, inside cloud droplets suggests the possibility of

  9. Energy landscapes shape microbial communities in hydrothermal systems on the Arctic Mid-Ocean Ridge

    OpenAIRE

    Dahle, H?kon; ?kland, Ingeborg; Thorseth, Ingunn H; Pederesen, Rolf B; Steen, Ida H

    2015-01-01

    Methods developed in geochemical modelling combined with recent advances in molecular microbial ecology provide new opportunities to explore how microbial communities are shaped by their chemical surroundings. Here, we present a framework for analyses of how chemical energy availability shape chemotrophic microbial communities in hydrothermal systems through an investigation of two geochemically different basalt-hosted hydrothermal systems on the Arctic Mid-Ocean Ridge: the Soria Moria Vent f...

  10. DNA barcoding of Arctic Ocean holozooplankton for species identification and recognition

    Science.gov (United States)

    Bucklin, Ann; Hopcroft, Russell R.; Kosobokova, Ksenia N.; Nigro, Lisa M.; Ortman, Brian D.; Jennings, Robert M.; Sweetman, Christopher J.

    2010-01-01

    Zooplankton species diversity and distribution are important measures of environmental change in the Arctic Ocean, and may serve as 'rapid-responders' of climate-induced changes in this fragile ecosystem. The scarcity of taxonomists hampers detailed and up-to-date monitoring of these patterns for the rarer and more problematic species. DNA barcodes (short DNA sequences for species recognition and discovery) provide an alternative approach to accurate identification of known species, and can speed routine analysis of zooplankton samples. During 2004-2008, zooplankton samples were collected during cruises to the central Arctic Ocean and Chukchi Sea. A ˜700 base-pair region of the mitochondrial cytochrome oxidase I (mtCOI) gene was amplified and sequenced for 82 identified specimens of 41 species, including cnidarians (six hydrozoans, one scyphozoan), arthropod crustaceans (five amphipods, 24 copepods, one decapod, and one euphausiid); two chaetognaths; and one nemertean. Phylogenetic analysis used the Neighbor-Joining algorithm with Kimura-2-Parameter (K-2-P) distances, with 1000-fold bootstrapping. K-2-P genetic distances between individuals of the same species ranged from 0.0 to 0.2; genetic distances between species ranged widely from 0.1 to 0.7. The mtCOI gene tree showed monophyly (at 100% bootstrap value) for each of the 26 species for which more than one individual was analyzed. Of seven genera for which more than one species was analyzed, four were shown to be monophyletic; three genera were not resolved. At higher taxonomic levels, only the crustacean order Copepoda was resolved, with bootstrap value of 83%. The mtCOI barcodes accurately discriminated and identified known species of 10 taxonomic groups of Arctic Ocean holozooplankton. A comprehensive DNA barcode database for the estimated 300 described species of Arctic holozooplankton will allow rapid assessment of species diversity and distribution in this climate-vulnerable ocean ecosystem.

  11. Sea level variability in the Arctic Ocean observed by satellite altimetry

    OpenAIRE

    Prandi, P.; Ablain, M.; Cazenave, A.; Picot, N.

    2012-01-01

    We investigate sea level variability in the Arctic Ocean from observations. Variability estimates are derived both at the basin scale and on smaller local spatial scales. The periods of the signals studied vary from high frequency (intra-annual) to long term trends. We also investigate the mechanisms responsible for the observed variability. Different data types are used, the main one being a recent reprocessing of satellite altimetry data...

  12. HY-2A satellite altimetric data evaluation in the Arctic ocean

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Andersen, Ole Baltazar

    2014-01-01

    in the Arctic Ocean. The results demonstrates that the HY-2 data shows higher standard variation and mean sea level than AltiKa and CryoSat-2 data during HY-2 cycle 49 (20130803 and 20130817) with more available sea level measurements than CryoSat-2 satellite altimetry. Moreover, consistent sea level variation...... is observed from AltiKa and CryoSat-2 monthly sea level time series....

  13. The simulated response of dimethylsulfide production in the Arctic Ocean to global warming

    International Nuclear Information System (INIS)

    Gabric, Albert J.; Qu, Bo; Hirst, Anthony C.

    2005-01-01

    Sulfate aerosols (of both biogenic and anthropogenic origin) play a key role in the Earth's radiation balance both directly through scattering and absorption of solar and terrestrial radiation, and indirectly by modifying cloud microphysical properties. However, the uncertainties associated with radiative forcing of climate due to aerosols substantially exceed those associated with the greenhouse gases. The major source of sulfate aerosols in the remote marine atmosphere is the biogenic compound dimethylsulfide (DMS), which is ubiquitous in the world's oceans and is synthesized by plankton. Climate models point to significant future changes in sea-ice cover in the Arctic Ocean due to warming. This will have consequences for primary production and the sea-to-air flux of a number of biogenic compounds, including DMS. In this paper we discuss the impact of warming on the future production of DMS in the Arctic Ocean. A DMS production model has been calibrated to current climate conditions with satellite ocean colour data (SeaWiFS) using a genetic algorithm, an efficient non-derivative based optimization technique. We use the CSIRO Mk 2 climate model to force the DMS model under enhanced greenhouse climate conditions. We discuss the simulated change in DMS flux and its consequences for future aerosol production and the radiative budget of the Arctic. Significant decreases in sea-ice cover (by 18.5% annually and 61% in summer-autumn), increases in mean annual sea surface temperature of 1 deg C, and a decrease of mixed layer depth by 13% annually are predicted to result in annual DMS flux increases of over 80% by the time of equivalent CO 2 tripling (2080). Estimates of the impact of this increase in DMS emissions suggest significant changes to summer aerosol concentrations and the radiative balance in the Arctic region

  14. Historical temperature, salinity, oxygen, nutrients and meteorological data collected in the Arctic Ocean and Atlantic Ocean by various countries from 20 Jul 1870 to 17 Jul 1995 (NODC Accession 0085914)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Historical temperature, salinity, oxygen, nutrients and meteorological data collected in the Arctic Ocean and Atlantic Ocean by various countries from 1870 to 1995,...

  15. Profile data from CTD casts aboard the F/V Ocean Explorer in the Arctic Ocean and Beaufort Sea from 2008-08-06 to 2008-08-22 (NODC Accession 0001920)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This profile data aboard the F/V Ocean Explorer in the Arctic Ocean and Beaufort Sea from August 6, 2008 to August 22, 2008 was supported by the Minerals Management...

  16. Phagotrophy by the picoeukaryotic green alga Micromonas: implications for Arctic Oceans.

    Science.gov (United States)

    McKie-Krisberg, Zaid M; Sanders, Robert W

    2014-10-01

    Photosynthetic picoeukaryotes (PPE) are recognized as major primary producers and contributors to phytoplankton biomass in oceanic and coastal environments. Molecular surveys indicate a large phylogenetic diversity in the picoeukaryotes, with members of the Prymnesiophyceae and Chrysophyseae tending to be more common in open ocean waters and Prasinophyceae dominating coastal and Arctic waters. In addition to their role as primary producers, PPE have been identified in several studies as mixotrophic and major predators of prokaryotes. Mixotrophy, the combination of photosynthesis and phagotrophy in a single organism, is well established for most photosynthetic lineages. However, green algae, including prasinophytes, were widely considered as a purely photosynthetic group. The prasinophyte Micromonas is perhaps the most common picoeukaryote in coastal and Arctic waters and is one of the relatively few cultured representatives of the picoeukaryotes available for physiological investigations. In this study, we demonstrate phagotrophy by a strain of Micromonas (CCMP2099) isolated from Arctic waters and show that environmental factors (light and nutrient concentration) affect ingestion rates in this mixotroph. In addition, we show size-selective feeding with a preference for smaller particles, and determine P vs I (photosynthesis vs irradiance) responses in different nutrient conditions. If other strains have mixotrophic abilities similar to Micromonas CCMP2099, the widespread distribution and frequently high abundances of Micromonas suggest that these green algae may have significant impact on prokaryote populations in several oceanic regimes.

  17. Projected Impact of Climate Change on the Water and Salt Budgets of the Arctic Ocean by a Global Climate Model

    Science.gov (United States)

    Miller, James R.; Russell, Gary L.

    1996-01-01

    The annual flux of freshwater into the Arctic Ocean by the atmosphere and rivers is balanced by the export of sea ice and oceanic freshwater. Two 150-year simulations of a global climate model are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. Relative to the control, the last 50-year period of the GHG experiment indicates that the total inflow of water from the atmosphere and rivers increases by 10% primarily due to an increase in river discharge, the annual sea-ice export decreases by about half, the oceanic liquid water export increases, salinity decreases, sea-ice cover decreases, and the total mass and sea-surface height of the Arctic Ocean increase. The closed, compact, and multi-phased nature of the hydrologic cycle in the Arctic Ocean makes it an ideal test of water budgets that could be included in model intercomparisons.

  18. Determination of a Critical Sea Ice Thickness Threshold for the Central Arctic Ocean

    Science.gov (United States)

    Ford, V.; Frauenfeld, O. W.; Nowotarski, C. J.

    2017-12-01

    While sea ice extent is readily measurable from satellite observations and can be used to assess the overall survivability of the Arctic sea ice pack, determining the spatial variability of sea ice thickness remains a challenge. Turbulent and conductive heat fluxes are extremely sensitive to ice thickness but are dominated by the sensible heat flux, with energy exchange expected to increase with thinner ice cover. Fluxes over open water are strongest and have the greatest influence on the atmosphere, while fluxes over thick sea ice are minimal as heat conduction from the ocean through thick ice cannot reach the atmosphere. We know that turbulent energy fluxes are strongest over open ocean, but is there a "critical thickness of ice" where fluxes are considered non-negligible? Through polar-optimized Weather Research and Forecasting model simulations, this study assesses how the wintertime Arctic surface boundary layer, via sensible heat flux exchange and surface air temperature, responds to sea ice thinning. The region immediately north of Franz Josef Land is characterized by a thickness gradient where sea ice transitions from the thickest multi-year ice to the very thin marginal ice seas. This provides an ideal location to simulate how the diminishing Arctic sea ice interacts with a warming atmosphere. Scenarios include both fixed sea surface temperature domains for idealized thickness variability, and fixed ice fields to detect changes in the ocean-ice-atmosphere energy exchange. Results indicate that a critical thickness threshold exists below 1 meter. The threshold is between 0.4-1 meters thinner than the critical thickness for melt season survival - the difference between first year and multi-year ice. Turbulent heat fluxes and surface air temperature increase as sea ice thickness transitions from perennial ice to seasonal ice. While models predict a sea ice free Arctic at the end of the warm season in future decades, sea ice will continue to transform

  19. Secondary organic aerosols over oceans via oxidation of isoprene and monoterpenes from Arctic to Antarctic.

    Science.gov (United States)

    Hu, Qi-Hou; Xie, Zhou-Qing; Wang, Xin-Ming; Kang, Hui; He, Quan-Fu; Zhang, Pengfei

    2013-01-01

    Isoprene and monoterpenes are important precursors of secondary organic aerosols (SOA) in continents. However, their contributions to aerosols over oceans are still inconclusive. Here we analyzed SOA tracers from isoprene and monoterpenes in aerosol samples collected over oceans during the Chinese Arctic and Antarctic Research Expeditions. Combined with literature reports elsewhere, we found that the dominant tracers are the oxidation products of isoprene. The concentrations of tracers varied considerably. The mean average values were approximately one order of magnitude higher in the Northern Hemisphere than in the Southern Hemisphere. High values were generally observed in coastal regions. This phenomenon was ascribed to the outflow influence from continental sources. High levels of isoprene could emit from oceans and consequently have a significant impact on marine SOA as inferred from isoprene SOA during phytoplankton blooms, which may abruptly increase up to 95 ng/m³ in the boundary layer over remote oceans.

  20. Arctic Ocean outflow and glacier–ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland

    Directory of Open Access Journals (Sweden)

    I. A. Dmitrenko

    2017-12-01

    Full Text Available The first-ever conductivity–temperature–depth (CTD observations on the Wandel Sea shelf in northeastern Greenland were collected in April–May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014–2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature–salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean–glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

  1. Production of fluorescent dissolved organic matter in Arctic Ocean sediments

    Science.gov (United States)

    Chen, Meilian; Kim, Ji-Hoon; Nam, Seung-Il; Niessen, Frank; Hong, Wei-Li; Kang, Moo-Hee; Hur, Jin

    2016-12-01

    Little is known about the production of fluorescent dissolved organic matter (FDOM) in the anoxic oceanic sediments. In this study, sediment pore waters were sampled from four different sites in the Chukchi-East Siberian Seas area to examine the bulk dissolved organic carbon (DOC) and their optical properties. The production of FDOM, coupled with the increase of nutrients, was observed above the sulfate-methane-transition-zone (SMTZ). The presence of FDOM was concurrent with sulfate reduction and increased alkalinity (R2 > 0.96, p  0.95, p CDOM and FDOM to the overlying water column, unearthing a channel of generally bio-refractory and pre-aged DOM to the oceans.

  2. Temperature, salinity, conductivity, and other measurements collected in the Northern Ocean as part of the Arctic Experiment in 1994 (NODC Accession 0002728)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Investigation of thermohaline circulation in Nordic Seas, hydrography and pathways of Atlantic water summer Arctic experiments

  3. Meteorological, oceanographic, and buoy data from JAMSTEC from five drifting buoys, named J-CAD (JAMSTEC Compact Arctic Drifter) in the Arctic Ocean from 2000 to 2003 (NODC Accession 0002201)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 1999, JAMSTEC and MetOcean Data System Ltd. developed a new drifting buoy, named J-CAD (JAMSTEC Compact Arctic Drifter), to conduct long-term observations in the...

  4. What Drives the Variability of the Atlantic Water Circulation in the Arctic Ocean?

    Science.gov (United States)

    Lique, C.; Johnson, H. L.

    2016-02-01

    The Atlantic Water (AW) layer in the Arctic Basin is isolated from the atmosphere by the overlaying surface layer; yet observations of the AW pan-Arctic boundary current have revealed that the velocities in this layer exhibit significant variations on all timescales. Here, analysis of a global ocean/sea ice model hindcast, complemented by experiments performed with an idealized process model, are used to investigate what controls the variability of AW circulation, with a focus on the role of wind forcing. The AW circulation carries the imprint of wind variations, both remotely over the Nordic and Barents seas where they force variability on the AW inflow to the Arctic Basin, and locally over the Arctic Basin through the forcing of the wind-driven Beaufort gyre, which modulates and transfers the wind variability to the AW layer. Our results further suggest that understanding variability in the large amount of heat contained within the AW layer requires a better understanding of the circulation within both AW and surface layers.

  5. Diazotroph Diversity in the Sea Ice, Melt Ponds, and Surface Waters of the Eurasian Basin of the Central Arctic Ocean.

    Science.gov (United States)

    Fernández-Méndez, Mar; Turk-Kubo, Kendra A; Buttigieg, Pier L; Rapp, Josephine Z; Krumpen, Thomas; Zehr, Jonathan P; Boetius, Antje

    2016-01-01

    The Eurasian basin of the Central Arctic Ocean is nitrogen limited, but little is known about the presence and role of nitrogen-fixing bacteria. Recent studies have indicated the occurrence of diazotrophs in Arctic coastal waters potentially of riverine origin. Here, we investigated the presence of diazotrophs in ice and surface waters of the Central Arctic Ocean in the summer of 2012. We identified diverse communities of putative diazotrophs through targeted analysis of the nifH gene, which encodes the iron protein of the nitrogenase enzyme. We amplified 529 nifH sequences from 26 samples of Arctic melt ponds, sea ice and surface waters. These sequences resolved into 43 clusters at 92% amino acid sequence identity, most of which were non-cyanobacterial phylotypes from sea ice and water samples. One cyanobacterial phylotype related to Nodularia sp. was retrieved from sea ice, suggesting that this important functional group is rare in the Central Arctic Ocean. The diazotrophic community in sea-ice environments appear distinct from other cold-adapted diazotrophic communities, such as those present in the coastal Canadian Arctic, the Arctic tundra and glacial Antarctic lakes. Molecular fingerprinting of nifH and the intergenic spacer region of the rRNA operon revealed differences between the communities from river-influenced Laptev Sea waters and those from ice-related environments pointing toward a marine origin for sea-ice diazotrophs. Our results provide the first record of diazotrophs in the Central Arctic and suggest that microbial nitrogen fixation may occur north of 77°N. To assess the significance of nitrogen fixation for the nitrogen budget of the Arctic Ocean and to identify the active nitrogen fixers, further biogeochemical and molecular biological studies are needed.

  6. Diazotroph diversity in the sea ice, melt ponds and surface waters of the Eurasian Basin of the Central Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Mar Fernández-Méndez

    2016-11-01

    Full Text Available The Eurasian basin of the Central Arctic Ocean is nitrogen limited, but little is known about the presence and role of nitrogen-fixing bacteria. Recent studies have indicated the occurrence of diazotrophs in Arctic coastal waters potentially of riverine origin. Here, we investigated the presence of diazotrophs in ice and surface waters of the Central Arctic Ocean in the summer of 2012. We identified diverse communities of putative diazotrophs through targeted analysis of the nifH gene, which encodes the iron protein of the nitrogenase enzyme. We amplified 529 nifH sequences from 26 samples of Arctic melt ponds, sea ice and surface waters. These sequences resolved into 43 clusters at 92% amino acid sequence identity, most of which were non-cyanobacterial phylotypes from sea ice and water samples. One cyanobacterial phylotype related to Nodularia sp. was retrieved from sea ice, suggesting that this important functional group is rare in the Central Arctic Ocean. The diazotrophic community in sea-ice environments appear distinct from other cold-adapted diazotrophic communities, such as those present in the coastal Canadian Arctic, the Arctic tundra and glacial Antarctic lakes. Molecular fingerprinting of nifH and the intergenic spacer region of the rRNA operon revealed differences between the communities from river-influenced Laptev Sea waters and those from ice-related environments pointing towards a marine origin for sea-ice diazotrophs. Our results provide the first record of diazotrophs in the Central Arctic and suggest that microbial nitrogen fixation may occur north of 77ºN. To assess the significance of nitrogen fixation for the nitrogen budget of the Arctic Ocean and to identify the active nitrogen fixers, further biogeochemical and molecular biological studies are needed.

  7. The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

    NARCIS (Netherlands)

    Cózar, Andrés; Martí, Elisa; Duarte, Carlos M; García-de-Lomas, Juan; van Sebille, Erik|info:eu-repo/dai/nl/304831921; Ballatore, Thomas J; Eguíluz, Victor M; González-Gordillo, J Ignacio; Pedrotti, Maria L; Echevarría, Fidel; Troublè, Romain; Irigoien, Xabier

    The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively

  8. Subtropical Arctic Ocean temperatures during the Palaeocene/Eocene thermal maximum

    Science.gov (United States)

    Sluijs, A.; Schouten, S.; Pagani, M.; Woltering, M.; Brinkhuis, H.; Damste, J.S.S.; Dickens, G.R.; Huber, M.; Reichart, G.-J.; Stein, R.; Matthiessen, J.; Lourens, L.J.; Pedentchouk, N.; Backman, J.; Moran, K.; Clemens, S.; Cronin, T.; Eynaud, F.; Gattacceca, J.; Jakobsson, M.; Jordan, R.; Kaminski, M.; King, J.; Koc, N.; Martinez, N.C.; McInroy, D.; Moore, T.C.; O'Regan, M.; Onodera, J.; Palike, H.; Rea, B.; Rio, D.; Sakamoto, T.; Smith, D.C.; St John, K.E.K.; Suto, I.; Suzuki, N.; Takahashi, K.; Watanabe, M. E.; Yamamoto, M.

    2006-01-01

    The Palaeocene/Eocene thermal maximum, ???55 million years ago, was a brief period of widespread, extreme climatic warming, that was associated with massive atmospheric greenhouse gas input. Although aspects of the resulting environmental changes are well documented at low latitudes, no data were available to quantify simultaneous changes in the Arctic region. Here we identify the Palaeocene/Eocene thermal maximum in a marine sedimentary sequence obtained during the Arctic Coring Expedition. We show that sea surface temperatures near the North Pole increased from ???18??C to over 23??C during this event. Such warm values imply the absence of ice and thus exclude the influence of ice-albedo feedbacks on this Arctic warming. At the same time, sea level rose while anoxic and euxinic conditions developed in the ocean's bottom waters and photic zone, respectively. Increasing temperature and sea level match expectations based on palaeoclimate model simulations, but the absolute polar temperatures that we derive before, during and after the event are more than 10??C warmer than those model-predicted. This suggests that higher-than-modern greenhouse gas concentrations must have operated in conjunction with other feedback mechanisms-perhaps polar stratospheric clouds or hurricane-induced ocean mixing-to amplify early Palaeogene polar temperatures. ?? 2006 Nature Publishing Group.

  9. Pliocene cooling enhanced by flow of low-salinity Bering Sea water to the Arctic Ocean.

    Science.gov (United States)

    Horikawa, Keiji; Martin, Ellen E; Basak, Chandranath; Onodera, Jonaotaro; Seki, Osamu; Sakamoto, Tatsuhiko; Ikehara, Minoru; Sakai, Saburo; Kawamura, Kimitaka

    2015-06-29

    Warming of high northern latitudes in the Pliocene (5.33-2.58 Myr ago) has been linked to the closure of the Central American Seaway and intensification of North Atlantic Deep Water. Subsequent cooling in the late Pliocene may be related to the effects of freshwater input from the Arctic Ocean via the Bering Strait, disrupting North Atlantic Deep Water formation and enhancing sea ice formation. However, the timing of Arctic freshening has not been defined. Here we present neodymium and lead isotope records of detrital sediment from the Bering Sea for the past 4.3 million years. Isotopic data suggest the presence of Alaskan glaciers as far back as 4.2 Myr ago, while diatom and C37:4 alkenone records show a long-term trend towards colder and fresher water in the Bering Sea beginning with the M2 glaciation (3.3 Myr ago). We argue that the introduction of low-salinity Bering Sea water to the Arctic Ocean by 3.3 Myr ago preconditioned the climate system for global cooling.

  10. The Experience of Barometric Drifter Application for Investigating the World Ocean Arctic Region

    Directory of Open Access Journals (Sweden)

    S.V. Motyzhev

    2016-08-01

    Full Text Available Efficiency of the problem solution to create a regionally-oriented data computing system for marine dynamics and ecosystem evolution modeling and forecasting (that should be capable for providing reliable information for managerial decision making, justifying future economic projects and adjusting the existing ones depends on development level of observational systems, environmental evolution, mathematical models and techniques for observational data assimilation. The analysis of the system as an observational segment of modern geo-informational technology allows us to draw a conclusion that the system of drifter observations is one of the most effective ones nowadays. Surface drifter network, continuously operating in the World Ocean, provides systematic operational data on the surface water circulation, thermal processes in the upper ocean and air pressure. Drifter data, acquired over the past 15 years, allowed one to improve and even change the existing concepts of patterns and mechanisms of regional climatic trend and hydrometeorological anomaly formation under effect of global processes in the Ocean – Atmosphere model (in the high latitudes as well. In the present paper the principle results of the analysis of expediency and feasibility of drifting systematic operative pressure field monitoring establishment in the near-surface atmosphere layer over the Arctic Ocean and the seas of the Russian Federation Arctic Zone have been considered. More than 30 drifters of BTC60/GPS/ice type, whose summarized lifetime as for June 2015 exceeded 6500 days, were deployed in the Arctic in 2012–2015. According to data acquired from the drifters, more than 155 000 air pressure readings were received. The most intensive drifter observations were carried out in two regions: in the Beaufort Sea – Canada Basin and in the Central Arctic. The results of experiments revealed that hardware-software solutions implemented in polar modifications of barometric

  11. Species richness and distribution of chondrichthyan fishes in the Arctic Ocean and adjacent seas

    DEFF Research Database (Denmark)

    Lynghammar, A.; Christiansen, J. S.; Mecklenburg, C. W.

    2013-01-01

    The sea ice cover decreases and human activity increases in Arctic waters. Fisheries and bycatch issues, shipping and petroleum exploitation (pollution issues) make it imperative to establish biological baselines for the marine fishes inhabiting the Arctic Ocean and adjacent seas (AOAS). Species...... richness, zoogeographic affiliations and Red List statuses among chondrichthyan fishes (Chondrichthyes) were examined across 16 AOAS regions as a first step towards credible conservation actions. Published literature and museum vouchers were consulted for presence/absence data. Although many regions...... are poorly sampled, 49 chondrichthyan species have been reported from the AOAS. Skates and rays are the most species-rich taxon, represented by 27 species in family Rajidae and one species in family Dasyatidae. The sharks comprise 20 species in 13 families and the chimaeras one species in family Chimaeridae...

  12. Patterns of Seasonal Heat Uptake and Release Over the Arctic Ocean Between 1979-2016

    Science.gov (United States)

    Helmberger, M. N.; Serreze, M. C.

    2017-12-01

    As the Arctic Ocean loses its sea ice cover, there is a stronger oceanic heat gain from the surface fluxes throughout the spring and summer; ultimately meaning that there is more energy to transfer out of the ocean to the atmosphere and outer space in the autumn and winter. Recent work has shown that the increased oceanic heat content at the end of summer in turn delays autumn ice growth, with implications for marine shipping and other economic activities. Some of the autumn and winter heat loss to the atmosphere is represented by evaporation, which increases the atmospheric water vapor content, and there is growing evidence that this is contributing to increases in regional precipitation. However, depending on patterns of seasonal sea ice retreat and weather conditions, the spring-summer heat uptake and autumn-winter heat loss can be highly variable from year to year and regionally. Here, we examine how the seasonality in upper ocean heat uptake and release has evolved over the past 37 years and the relationships between this seasonal heat gain and loss and the evolution of sea ice cover. We determine which regions have seen the largest increases in total seasonal heat uptake and how variable this uptake can be. Has the timing at which the Arctic Ocean (either as a whole or by region) transitions from an atmospheric energy sink to an atmospheric energy source (or from a source to a sink) appreciably changed? What changes have been observed in the seasonal rates of seasonal heat uptake and release? To begin answering these questions, use is made of surface fluxes from the ERA-Interim reanalysis and satellite-derived sea ice extent spanning the period 1979 through the present. Results from ERA-Interim will be compared to those from other reanalyses and satellite-derived flux estimates.

  13. Collection of Arctic Ocean Data from US Navy Submarines on the New SCICEX Program

    Science.gov (United States)

    Smethie, W. M.; Sambrotto, R.; Boyd, T.; Richter-Menge, J.; Corbett, J.

    2011-12-01

    The SCICEX submarine Arctic science program originated in the 1990s when six dedicated science cruises were conducted in the Arctic Ocean aboard US Navy Sturgeon class submarines. After the cold war era Sturgeon class submarines were retired, several Science Accommodation cruises, for which a few days for scientific measurements were added to planned submarine transits through the Arctic Ocean, were carried out when opportunities arose. Renewed interest in conducting further Science Accommodation cruises on a regular basis to better document and understand how the Arctic Ocean responds to climate change resulted in publication of a scientific plan in 2010 (http://www.arctic.gov/publications/scicex_plan.pdf). In the spring of 2011 testing of data collection and water sampling methods aboard newer Virginia and Seawolf class submarines on transit from a Navy ice camp in the Beaufort Sea, was conducted in order to develop protocols and evaluate techniques. Ice draft measurements were also taken in the vicinity of the ice camp and near the North Pole to evaluate new data collection systems. This evaluation will include a comparison of the ice draft data with a comprehensive set of in situ ice thickness measurements taken near the ice camp. Under-ice submarine-launched eXpendable Condutivity Temperature Depth (XCTD) probes were deployed from the USS Connecticut (SSN-22), a Seawolf class submarine, and the resulting profiles compared to CTD casts from the APLIS ice station and historical profiles. Water samples were collected through the hull for measurements of tritium, helium isotopes, oxygen isotopes, chlorofluorocarbons, sulfur hexafluoride, nutrients, dissolved organic carbon, bacterioplankton, phytoplankton and particulates levels. These samples were returned to Lamont-Doherty Earth Observatory and were in the process of being measured at the time this abstract was written. Measurements completed at this time indicate good samples can be collected for CFC-12

  14. Evolution of anomalies of salinity of surface waters of Arctic Ocean and their possible influence on climate changes

    Science.gov (United States)

    Popov, A.; Rubchenia, A.

    2009-04-01

    Numerous of model simulations of ice extent in Arctic Ocean predict almost full disappearance of sea ice in Arctic regions by 2050. However, the nature, as against models, does not suffer the unidirectional processes. By means of various feedback responses system aspires to come in an equilibrium condition. In Arctic regions one of the most powerful generators of a negative feedback is the fresh-water stream to Greenland Sea and Northern Atlantic. Increasing or decreasing of a fresh-water volume from the Arctic basin to Greenland Sea and Northern Atlantic results in significant changes in climatic system. At the Oceanology department of Arctic and Antarctic Research Institute (AARI) (St-Petersburg, Russia) in 2007, on the basis of the incorporated Russian-American database of the oceanographic data, reconstruction of long-term time series of average salinity of ocean surface was executed. The received time series describes the period from 1950 to 1993. For allocation of the processes determining formation of changes of average salinity of surface waters in Arctic basin the correlation analysis of interrelation of the received time series and several physical parameters which could affect formation of changes of salinity was executed. We found counter-intuitive result: formation of long-term changes of average salinity of surface waters of Arctic basin in the winter period does not depend on changes of a Siberian rivers runoff. Factors of correlation do not exceed -0,31. At the same time, clear inverse relationship of salinity of surface waters from volumes of the ice formed in flaw lead polynyas of the Siberian shelf seas is revealed. In this case factors of correlation change from -0,56 to -0,7. The maximum factor of correlation is -0,7. It characterizes interrelation of total volume of the ice formed in flaw lead polynyas of all seas of the Siberian shelf and average salinity of surface waters of Arctic basin. Thus, at increase of volumes of the ice formed in

  15. "Cold" Fixation: Reconciliation of Nitrogen Fixation Rates and Diazotroph Assemblages in the Arctic Ocean

    Science.gov (United States)

    Fong, A. A.; Waite, A.; Rost, B.; Richter, K. U.

    2016-02-01

    Measurements of biological nitrogen fixation are typically conducted in oligotrophic subtropical and tropical marine environments where concentrations of fixed inorganic nitrogen are low. To date, only a handful of nitrogen fixation studies have been conducted in high latitude marine environments, but further investigation is needed to resolve the distribution of cold ocean diazotrophic assemblages. Nitrogen fixation rates and nifH gene distributions were measured at seven stations from 5°E to 20°E, north of 81°N in the Arctic Ocean at the onset of summer 2015. Discrete water samples in ice-covered regions were collected from the sea surface to 200 m for 15N2-tracer additions and targeted nifH gene and transcript analyses. Previous work suggests that heterotrophic bacteria dominate diazotrophic communities in the Arctic Ocean. Therefore, additional nifH gene surveys of sinking particles were conducted to test for enrichment on organic matter-rich microenvironments. Together, these measurements aim to reconcile diazotrophic activity with microbial community composition, further elucidating how nitrogen fixers could impact current concepts in polar carbon and nutrient cycling.

  16. Temperature, salinity, and other data from CTD and XCTD casts in the Arctic Ocean from 26 March 1995 to 08 May 1995 (NODC Accession 0000474)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD, XCTD, and other data were collected in the Arctic Ocean from 26 March 1995 to 08 May 1995. Surface data were collected by CTD. XCTD data were corrected for...

  17. Temperature, salinity, and other data from buoy casts in the Arctic Ocean, Barents Sea and Beaufort Sea from 1948 to 1993 (NODC Accession 9800040)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and other data were collected using buoy casts in the Arctic Ocean, Barents Sea and Beaufort Sea from 1948 to 1993. Data were collected by the...

  18. Turbidity, SOLAR RADIATION - ATMOSPHERIC and other data from POLARSTERN in the Arctic Ocean from 1993-08-10 to 1993-09-24 (NODC Accession 9600042)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD); and other data were collected using ship POLARSTERN from Arctic Ocean. The data was collected from August 10, 1993 to...

  19. Zooplankton species identification and counts data from drifting station ARLIS II and Fletchers ice island T-3 in the Arctic Ocean from 19521229 to 19680129 (NODC Accession 6900643)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are counts of 3 copepod species collected during plankton tows in the Arctic Ocean from December 1952 through January 1968 by the University of...

  20. Absolute Geostrophic Velocity Inverted from the Polar Science Center Hydrographic Climatology (PHC3.0) of the Arctic Ocean with the P-Vector Method (NCEI Accession 0156425)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset (called PHC-V) comprises 3D gridded climatological fields of absolute geostrophic velocity of the Arctic Ocean inverted from the Polar science center...

  1. Phytoplankton data collected using net casts in the Arctic Ocean from the USCGC POLAR SEA from 26 July 1994 to 26 August 1994 (NODC Accession 0000770)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Phytoplankton data were collected using net casts from the USCGC POLAR SEA in the Arctic Ocean. Data were collected from 26 July 1994 to 26 August 1994. Data were...

  2. PRIMARY PRODUCTIVITY - PHYTOPLANKTON, CHLOROPHYLL A CONCENTRATION, and others in Arctic Ocean from 1959-08-03 to 2011-10-21 (NCEI Accession 0161176)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Arctic Ocean net primary productivity (NPP) was assembled for 1959-2011 from existing databases and recent polar research cruises. At each NPP station, if available,...

  3. Storm-driven Mixing and Potential Impact on the Arctic Ocean

    Science.gov (United States)

    Yang, Jiayan; Comiso, Josefino; Walsh, David; Krishfield, Richard; Honjo, Susumu; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Observations of the ocean, atmosphere, and ice made by Ice-Ocean Environmental Buoys (IOEBs) indicate that mixing events reaching the depth of the halocline have occurred in various regions in the Arctic Ocean. Our analysis suggests that these mixing events were mechanically forced by intense storms moving across the buoy sites. In this study, we analyzed these mixing events in the context of storm developments that occurred in the Beaufort Sea and in the general area just north of Fram Strait, two areas with quite different hydrographic structures. The Beaufort Sea is strongly influenced by inflow of Pacific water through Bering Strait, while the area north of Fram Strait is directly affected by the inflow of warm and salty North Atlantic water. Our analyses of the basin-wide evolution of the surface pressure and geostrophic wind fields indicate that the characteristics of the storms could be very different. The buoy-observed mixing occurred only in the spring and winter seasons when the stratification was relatively weak. This indicates the importance of stratification, although the mixing itself was mechanically driven. We also analyze the distribution of storms, both the long-term climatology as well as the patterns for each year in the last two decades. The frequency of storms is also shown to be correlated- (but not strongly) to Arctic Oscillation indices. This study indicates that the formation of new ice that leads to brine rejection is unlikely the mechanism that results in the type of mixing that could overturn the halocline. On the other hand, synoptic-scale storms can force mixing deep enough to the halocline and thermocline layer. Despite a very stable stratification associated with the Arctic halocline, the warm subsurface thermocline water is not always insulated from the mixed layer.

  4. Pelagic Nitrogen Cycle Observations In The Arctic Ocean - How Might They Change In Response To Ocean Acidification?

    Science.gov (United States)

    Clark, D. R.; Rees, A.; Brown, I.; Al-Moosawi, L.; Cripps, G.

    2016-02-01

    Phytoplankton forms the base of marine food webs by assimilating nutrients and generating biomass that supports higher trophic levels. Conversely, marine heterotrophs degrade organic matter produced by phytoplankton and recycle nutrients, maintaining food web integrity. We investigated the assimilation and regeneration of dissolved inorganic nitrogen (DIN) at stations located in the Arctic Ocean. In addition, we measured the concentration of nitrous oxide, a by-product of N-regeneration (specifically nitrification) and a climatically active gas. Measurements demonstrated the simultaneous regeneration and assimilation of ammonium, nitrite and nitrate at open ocean, ice-edge and within-ice locations. Ammonium was regenerated and assimilated within the range 0.2-4.5 nmol·L-1·h-1 and 0.5-24.8 nmol·L-1·h-1 respectively. Nitrite was regenerated and assimilated within the range 0.1-9.2 nmol·L-1·h-1 and 0.0-6.9 nmol·L-1·h-1 respectively. Nitrate was regenerated and assimilated within the range 0.3-372.7 nmol·L-1·h-1 and 0.1-48.3 nmol·L-1·h-1 respectively. Results indicated that the ice-edge was associated with enhanced DIN assimilation. The concentration of nitrous oxide (oxidation and the concentration of nitrous oxide did not respond in a clear or consistent way to OA treatments. In contrast, the regeneration of NH4+ increased in response to elevated PCO2. The bacterial degradation of organic matter may be enhanced in the Arctic Ocean in response to OA, potentially modifying DIN pool composition and concentration in the future.

  5. Operationalising a social-ecological system perspective on the Arctic Ocean.

    Science.gov (United States)

    Crépin, Anne-Sophie; Gren, Åsa; Engström, Gustav; Ospina, Daniel

    2017-12-01

    We propose a framework to support management that builds on a social-ecological system perspective on the Arctic Ocean. We illustrate the framework's application for two policy-relevant scenarios of climate-driven change, picturing a shift in zooplankton composition and alternatively a crab invasion. We analyse archetypical system dynamics between the socio-economic, the natural, and the governance systems in these scenarios. Our holistic approach can help managers identify looming problems arising from complex system interactions and prioritise among problems and solutions, even when available data are limited.

  6. Environmental Sensitivity Index (ESI) Atlas: Northwest Arctic, Alaska, volume 2, maps and geographic information systems data (NODC Accession 0046028)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set comprises the Environmental Sensitivity Index (ESI) data for Northwest Arctic, Alaska. ESI data characterize estuarine environments and wildlife by...

  7. Distribution and long-range transport of polyfluoroalkyl substances in the Arctic, Atlantic Ocean and Antarctic coast

    International Nuclear Information System (INIS)

    Zhao Zhen; Xie Zhiyong; Möller, Axel; Sturm, Renate; Tang Jianhui; Zhang Gan; Ebinghaus, Ralf

    2012-01-01

    The global distribution and long-range transport of polyfluoroalkyl substances (PFASs) were investigated using seawater samples collected from the Greenland Sea, East Atlantic Ocean and the Southern Ocean in 2009–2010. Elevated levels of ΣPFASs were detected in the North Atlantic Ocean with the concentrations ranging from 130 to 650 pg/L. In the Greenland Sea, the ΣPFASs concentrations ranged from 45 to 280 pg/L, and five most frequently detected compounds were perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS), perfluorohexanoic acid (PFHxA), perfluorooctane sulfonate (PFOS) and perfluorobutane sulfonate (PFBS). PFOA (15 pg/L) and PFOS (25–45 pg/L) were occasionally found in the Southern Ocean. In the Atlantic Ocean, the ΣPFASs concentration decreased from 2007 to 2010. The elevated PFOA level that resulted from melting snow and ice in Greenland Sea implies that the Arctic may have been driven by climate change and turned to be a source of PFASs for the marine ecosystem. - Highlights: ► PFOA is released from the Arctic snow and ice and might be transport southwards to the Atlantic. ► Decline temporal trends of PFASs are present in the Northern Hemisphere in the Atlantic. ► PFOS has elevate concentration in comparison to PFOA in the Southern Ocean. - Polyfluoroalkyl substances (PFASs) have been reported for the Arctic, Atlantic and the Southern Ocean, which improves understanding the fate of PFASs in the global oceans.

  8. Monitoring and assessment of ocean acidification in the Arctic Ocean-A scoping paper

    Science.gov (United States)

    Robbins, Lisa L.; Yates, Kimberly K.; Feely, Richard; Fabry, Victoria

    2010-01-01

    Carbon dioxide (CO2) in the atmosphere is absorbed at the ocean surface by reacting with seawater to form a weak, naturally occurring acid called carbonic acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution. Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats. The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

  9. Summertime calcium carbonate undersaturation in shelf waters of the western Arctic Ocean – how biological processes exacerbate the impact of ocean acidification

    Directory of Open Access Journals (Sweden)

    N. R. Bates

    2013-08-01

    Full Text Available The Arctic Ocean accounts for only 4% of the global ocean area, but it contributes significantly to the global carbon cycle. Recent observations of seawater CO2-carbonate chemistry in shelf waters of the western Arctic Ocean, primarily in the Chukchi Sea, from 2009 to 2011 indicate that bottom waters are seasonally undersaturated with respect to calcium carbonate (CaCO3 minerals, particularly aragonite. Nearly 40% of sampled bottom waters on the shelf have saturation states less than one for aragonite (i.e., Ωaragonite 3-secreting organisms, while 80% of bottom waters present had Ωaragonite values less than 1.5. Our observations indicate seasonal reduction of saturation states (Ω for calcite (Ωcalcite and aragonite (Ωaragonite in the subsurface in the western Arctic by as much as 0.8 and 0.5, respectively. Such data indicate that bottom waters of the western Arctic shelves were already potentially corrosive for biogenic and sedimentary CaCO3 for several months each year. Seasonal changes in Ω are imparted by a variety of factors such as phytoplankton photosynthesis, respiration/remineralization of organic matter and air–sea gas exchange of CO2. Combined, these processes either increase or enhance in surface and subsurface waters, respectively. These seasonal physical and biological processes also act to mitigate or enhance the impact of Anthropocene ocean acidification (OA on Ω in surface and subsurface waters, respectively. Future monitoring of the western Arctic shelves is warranted to assess the present and future impact of ocean acidification and seasonal physico-biogeochemical processes on Ω values and Arctic marine ecosystems.

  10. Analysis of sea-level reconstruction techniques for the Arctic Ocean

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

    Sea-level reconstructions spanning several decades have been examined in numerous studies for most of the world's ocean areas, where satellite missions such as TOPEX/Poseidon and Jason-1 and -2 have provided much-improved knowledge of variability and long-term changes in sea level. However......, these dedicated oceanographic missions are limited in coverage to between ±66° latitude, and satellite altimeter data at higher latitudes is of a substantially worse quality. Following the approach of Church et al. (2004), we apply a model based on empirical orthogonal functions (EOFs) to the Arctic Ocean......, constrained by tide gauge records. A major challenge for this area is the sparsity of both satellite and tide gauge data beyond what can be covered with interpolation, necessitating a time-variable model and consideration to data preprocessing, including selection of appropriate tide gauges. In order to have...

  11. The atmospheric boundary layer response to the dynamic new Arctic Ocean

    Science.gov (United States)

    Wu, D. L.; Ganeshan, M.

    2016-12-01

    The increasing ice-free area in the Arctic Ocean has transformed its climate system to one with more dynamic boundary layer clouds and seasonal sea ice. During the fall freeze season, the surface sensible heat flux (SSHF) is a crucial mechanism for the loss of excessive ocean heat to the atmosphere, and it has been speculated to play an important role in the recent cloud cover increase and boundary layer (BL) instability observed in the Beaufort and Chukchi seas. Based on multi-year Japanese cruise ship observations from the ice-strengthened R/V Mirai, we are able to characterize the late summer and early fall ocean-BL interactions in this region. Although the BL is found to be well-mixed more than 90% of the time, the SSHF can explain only 10% of the mixed layer height variability. It is the cloud-generated convective turbulence that apparently dominates BL mixing in this ice-free region, which is similar to previous in-situ observations (SHEBA, ASCOS) over sea ice. The SSHF, however, may contribute to BL instability during conditions of uplift (low-pressure), and the presence of the highly stable stratus cloud regime. The efficiency of sensible heat exchange is low during cold air advection (associated with the stratocumulus cloud regime) despite an enhanced ocean-atmosphere temperature difference (ΔT). In general, surface-generated mixing is favored during episodes of high surface wind speeds as opposed to pronounced ΔT. Our analysis suggests a weak local response of the boundary layer stability to the loss of sea ice cover during late summer, which is masked by the strong influence of the large-scale circulation (and clouds). Apart from the fall season, we also studied the Arctic Ocean BL properties during the cold months (Nov-Apr) using multi-year satellite measurements (COSMIC RO). As the boundary layer is typically stable at this time, one might expect major differences in the nature of surface-atmosphere coupling compared to that observed during late

  12. Synthesis of integrated primary production in the Arctic Ocean: II. In situ and remotely sensed estimates

    Science.gov (United States)

    Hill, Victoria J.; Matrai, Patricia A.; Olson, Elise; Suttles, S.; Steele, Mike; Codispoti, L. A.; Zimmerman, Richard C.

    2013-03-01

    Recent warming of surface waters, accompanied by reduced ice thickness and extent may have significant consequences for climate-driven changes of primary production (PP) in the Arctic Ocean (AO). However, it has been difficult to obtain a robust benchmark estimate of pan-Arctic PP necessary for evaluating change. This paper provides an estimate of pan-Arctic PP prior to significant warming from a synthetic analysis of the ARCSS-PP database of in situ measurements collected from 1954 to 2007 and estimates derived from satellite-based observations from 1998 to 2007. Vertical profiles of in situ chlorophyll a (Chl a) and PP revealed persistent subsurface peaks in biomass and PP throughout the AO during most of the summer period. This was contradictory with the commonly assumed exponential decrease in PP with depth on which prior satellite-derived estimates were based. As remotely sensed Chl a was not a good predictor of integrated water column Chl a, accurate satellite-based modeling of vertically integrated primary production (IPPsat), requires knowledge of the subsurface distribution of phytoplankton, coincident with the remotely sensed ocean color measurements. We developed an alternative approach to modeling PP from satellite observations by incorporating climatological information on the depths of the euphotic zone and the mixed layer that control the distribution of phytoplankton that significantly improved the fidelity of satellite derived PP to in situ observations. The annual IPP of the Arctic Ocean combining both in situ and satellite based estimates was calculated here to be a minimum of 466 ± 94 Tg C yr-1 and a maximum of 993 ± 94 Tg C yr-1, when corrected for subsurface production. Inflow shelf seas account for 75% of annual IPP, while the central basin and Beaufort northern sea were the regions with the lowest annual integrated productivity, due to persistently stratified, oligotrophic and ice-covered conditions. Although the expansion of summertime

  13. Upper Arctic Ocean water masses harbor distinct communities of heterotrophic flagellates

    Directory of Open Access Journals (Sweden)

    A. Monier

    2013-06-01

    Full Text Available The ubiquity of heterotrophic flagellates (HFL in marine waters has been recognized for several decades, but the phylogenetic diversity of these small (ca. 0.8–20 μm cell diameter, mostly phagotrophic protists in the upper pelagic zone of the ocean is underappreciated. Community composition of microbes, including HFL, is the result of past and current environmental selection, and different taxa may be indicative of food webs that cycle carbon and energy very differently. While all oceanic water columns can be density stratified due to the temperature and salinity characteristics of different water masses, the Arctic Ocean is particularly well stratified, with nutrients often limiting in surface waters and most photosynthetic biomass confined to a subsurface chlorophyll maximum layer, where light and nutrients are both available. This physically well-characterized system provided an opportunity to explore the community diversity of HFL from different water masses within the water column. We used high-throughput DNA sequencing techniques as a rapid means of surveying the diversity of HFL communities in the southern Beaufort Sea (Canada, targeting the surface, the subsurface chlorophyll maximum layer (SCM and just below the SCM. In addition to identifying major clades and their distribution, we explored the micro-diversity within the globally significant but uncultivated clade of marine stramenopiles (MAST-1 to examine the possibility of niche differentiation within the stratified water column. Our results strongly suggested that HFL community composition was determined by water mass rather than geographical location across the Beaufort Sea. Future work should focus on the biogeochemical and ecological repercussions of different HFL communities in the face of climate-driven changes to the physical structure of the Arctic Ocean.

  14. CMIP5-based global wave climate projections including the entire Arctic Ocean

    Science.gov (United States)

    Casas-Prat, M.; Wang, X. L.; Swart, N.

    2018-03-01

    This study presents simulations of the global ocean wave climate corresponding to the surface winds and sea ice concentrations as simulated by five CMIP5 (Coupled Model Intercomparison Project Phase 5) climate models for the historical (1979-2005) and RCP8.5 scenario future (2081-2100) periods. To tackle the numerical complexities associated with the inclusion of the North Pole, the WAVEWATCH III (WW3) wave model was used with a customized unstructured Spherical Multi-Cell grid of ∼100 km offshore and ∼50 km along coastlines. The climate model simulated wind and sea ice data, and the corresponding WW3 simulated wave data, were evaluated against reanalysis and hindcast data. The results show that all the five sets of wave simulations projected lower waves in the North Atlantic, corresponding to decreased surface wind speeds there in the warmer climate. The selected CMIP5 models also consistently projected an increase in the surface wind speed in the Southern Hemisphere (SH) mid-high latitudes, which translates in an increase in the WW3 simulated significant wave height (Hs) there. The higher waves are accompanied with increased peak wave period and increased wave age in the East Pacific and Indian Oceans, and a significant counterclockwise rotation in the mean wave direction in the Southern Oceans. The latter is caused by more intense waves from the SH traveling equatorward and developing into swells. Future wave climate in the Arctic Ocean in summer is projected to be predominantly of mixed sea states, with the climatological mean of September maximum Hs ranging mostly 3-4 m. The new waves approaching Arctic coasts will be less fetch-limited as ice retreats since a predominantly southwards mean wave direction is projected in the surrounding seas.

  15. Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

    DEFF Research Database (Denmark)

    Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert

    2017-01-01

    The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal...... the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has...... interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater...

  16. Aerosol composition and sources in the central Arctic Ocean during ASCOS

    Science.gov (United States)

    Chang, R. Y.-W.; Leck, C.; Graus, M.; Müller, M.; Paatero, J.; Burkhart, J. F.; Stohl, A.; Orr, L. H.; Hayden, K.; Li, S.-M.; Hansel, A.; Tjernström, M.; Leaitch, W. R.; Abbatt, J. P. D.

    2011-10-01

    Measurements of submicron aerosol chemical composition were made over the central Arctic Ocean from 5 August to 8 September 2008 as a part of the Arctic Summer Cloud Ocean Study (ASCOS) using an aerosol mass spectrometer (AMS). The median levels of sulphate and organics for the entire study were 0.051 and 0.055 μ g m-3, respectively. Positive matrix factorisation was performed on the entire mass spectral time series and this enabled marine biogenic and continental sources of particles to be separated. These factors accounted for 33% and 36% of the sampled ambient aerosol mass, respectively, and they were both predominantly composed of sulphate, with 47% of the sulphate apportioned to marine biogenic sources and 48% to continental sources, by mass. Within the marine biogenic factor, the ratio of methane sulphonate to sulphate was 0.25 ± 0.02, consistent with values reported in the literature. The organic component of the continental factor was more oxidised than that of the marine biogenic factor, suggesting that it had a longer photochemical lifetime than the organics in the marine biogenic factor. The remaining ambient aerosol mass was apportioned to an organic-rich factor that could have arisen from a combination of marine and continental sources. In particular, given that the factor does not correlate with common tracers of continental influence, we cannot rule out that the organic factor arises from a primary marine source.

  17. Mercury in the atmosphere, snow and melt water ponds in the North Atlantic Ocean during Arctic summer.

    Science.gov (United States)

    Aspmo, Katrine; Temme, Christian; Berg, Torunn; Ferrari, Christophe; Gauchard, L Pierre-Alexis; Fain, Xavier; Wibetoe, Grethe

    2006-07-01

    Atmospheric mercury speciation measurements were performed during a 10 week Arctic summer expedition in the North Atlantic Ocean onboard the German research vessel RV Polarstern between June 15 and August 29, 2004. This expedition covered large areas of the North Atlantic and Arctic Oceans between latitudes 54 degrees N and 85 degrees N and longitudes 16 degrees W and 16 degrees E. Gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and mercury associated with particles (Hg-P) were measured during this study. In addition, total mercury in surface snow and meltwater ponds located on sea ice floes was measured. GEM showed a homogeneous distribution over the open North Atlantic Ocean (median 1.53 +/- 0.12 ng/m3), which is in contrast to the higher concentrations of GEM observed over sea ice (median 1.82 +/- 0.24 ng/m3). It is hypothesized that this results from either (re-) emission of mercury contained in snow and ice surfaces that was previously deposited during atmospheric mercury depletion events (AMDE) in the spring or evasion from the ocean due to increased reduction potential at high latitudes during Arctic summer. Measured concentrations of total mercury in surface snow and meltwater ponds were low (all samples RGM and Hg-P without a significant diurnal variability. These results indicate that the production and deposition of these reactive mercury species do not significantly contribute to the atmospheric mercury cycle in the North Atlantic Ocean during the Arctic summer.

  18. The Role of Ocean and Atmospheric Heat Transport in the Arctic Amplification

    Science.gov (United States)

    Vargas Martes, R. M.; Kwon, Y. O.; Furey, H. H.

    2017-12-01

    Observational data and climate model projections have suggested that the Arctic region is warming around twice faster than the rest of the globe, which has been referred as the Arctic Amplification (AA). While the local feedbacks, e.g. sea ice-albedo feedback, are often suggested as the primary driver of AA by previous studies, the role of meridional heat transport by ocean and atmosphere is less clear. This study uses the Community Earth System Model version 1 Large Ensemble simulation (CESM1-LE) to seek deeper understanding of the role meridional oceanic and atmospheric heat transports play in AA. The simulation consists of 40 ensemble members with the same physics and external forcing using a single fully coupled climate model. Each ensemble member spans two time periods; the historical period from 1920 to 2005 using the Coupled Model Intercomparison Project Phase 5 (CMIP5) historical forcing and the future period from 2006 to 2100 using the CMIP5 Representative Concentration Pathways 8.5 (RCP8.5) scenario. Each of the ensemble members are initialized with slightly different air temperatures. As the CESM1-LE uses a single model unlike the CMIP5 multi-model ensemble, the internal variability and the externally forced components can be separated more clearly. The projections are calculated by comparing the period 2081-2100 relative to the time period 2001-2020. The CESM1-LE projects an AA of 2.5-2.8 times faster than the global average, which is within the range of those from the CMIP5 multi-model ensemble. However, the spread of AA from the CESM1-LE, which is attributed to the internal variability, is 2-3 times smaller than that of the CMIP5 ensemble, which may also include the inter-model differences. CESM1LE projects a decrease in the atmospheric heat transport into the Arctic and an increase in the oceanic heat transport. The atmospheric heat transport is further decomposed into moisture transport and dry static energy transport. Also, the oceanic heat

  19. Trends in Arctic Ocean bottom pressure, sea surface height and freshwater content using GRACE and the ice-ocean model PIOMAS from 2008-2012

    Science.gov (United States)

    Peralta-Ferriz, Cecilia; Morison, James; Zhang, Jinlun; Bonin, Jennifer

    2014-05-01

    The variability of ocean bottom pressure (OBP) in the Arctic is dominated by the variations in sea surface height (SSH) from daily to monthly timescales. Conversely, OBP variability is dominated by the changes in the steric pressure (StP) at inter-annual timescales, particularly off the continental shelves. The combination of GRACE-derived ocean bottom pressure and ICESat altimetry-derived sea surface height variations in the Arctic Ocean have provided new means of identifying inter-annual trends in StP (StP = OBP-SSH) and associated freshwater content (FWC) of the Arctic region (Morison et al., 2012). Morison et al. (2012) showed that from 2004 to 2008, the FWC increased in the Beaufort Gyre and decreased in the Siberian and Central Arctic, resulting in a relatively small net basin-averaged FWC change. In this work, we investigate the inter-annual trends from 2008 to 2012 in OBP from GRACE, SSH from the state-of-the-art pan-Arctic ocean model PIOMAS -validated with tide and pressure gauges in the Arctic-, and compute the trends in StP and FWC from 2008-2012. We compare these results with the previous trends from 2005-2008 described in Morison et al. (2012). Our initial findings suggest increased salinity in the entire Arctic basin (relative to the climatological seasonal variation) from 2008-2012, compared to the preceding four years (2005-2008). We also find that the trends in OBP, SSH and StP from 2008-2012 present a different behavior during the spring-summer and fall-winter, unlike 2005-2008, in which the trends were generally consistent through all months of the year. It seems since 2009, when the Beaufort Gyre relaxed and the export of freshwater from the Canada Basin into the Canadian Archipelago and Fram Strait, via the Lincoln Sea, was anomalously large (de Steur et al., 2013), the Arctic Ocean has entered a new circulation regime. The causes of such changes in the inter-annual trends of OBP, SSH and StP -hence FWC-, associated with the changes in the

  20. Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties

    Directory of Open Access Journals (Sweden)

    J. Zábori

    2013-05-01

    Full Text Available Primary marine aerosols (PMAs are an important source of cloud condensation nuclei, and one of the key elements of the remote marine radiative budget. Changes occurring in the rapidly warming Arctic, most importantly the decreasing sea ice extent, will alter PMA production and hence the Arctic climate through a set of feedback processes. In light of this, laboratory experiments with Arctic Ocean water during both Arctic winter and summer were conducted and focused on PMA emissions as a function of season and water properties. Total particle number concentrations and particle number size distributions were used to characterize the PMA population. A comprehensive data set from the Arctic summer and winter showed a decrease in PMA concentrations for the covered water temperature (Tw range between −1°C and 15°C. A sharp decrease in PMA emissions for a Tw increase from −1°C to 4°C was followed by a lower rate of change in PMA emissions for Tw up to about 6°C. Near constant number concentrations for water temperatures between 6°C to 10°C and higher were recorded. Even though the total particle number concentration changes for overlapping Tw ranges were consistent between the summer and winter measurements, the distribution of particle number concentrations among the different sizes varied between the seasons. Median particle number concentrations for a dry diameter (DpDp > 0.125μm, the particle number concentrations during winter were mostly higher than in summer (up to 50%. The normalized particle number size distribution as a function of water temperature was examined for both winter and summer measurements. An increase in Tw from −1°C to 10°C during winter measurements showed a decrease in the peak of relative particle number concentration at about a Dp of 0.180μm, while an increase was observed for particles with Dp > 1μm. Summer measurements exhibited a relative shift to smaller particle sizes for an increase of Tw in the range

  1. Sea ice thermohaline dynamics and biogeochemistry in the Arctic Ocean: Empirical and model results

    Science.gov (United States)

    Duarte, Pedro; Meyer, Amelie; Olsen, Lasse M.; Kauko, Hanna M.; Assmy, Philipp; Rösel, Anja; Itkin, Polona; Hudson, Stephen R.; Granskog, Mats A.; Gerland, Sebastian; Sundfjord, Arild; Steen, Harald; Hop, Haakon; Cohen, Lana; Peterson, Algot K.; Jeffery, Nicole; Elliott, Scott M.; Hunke, Elizabeth C.; Turner, Adrian K.

    2017-07-01

    Large changes in the sea ice regime of the Arctic Ocean have occurred over the last decades justifying the development of models to forecast sea ice physics and biogeochemistry. The main goal of this study is to evaluate the performance of the Los Alamos Sea Ice Model (CICE) to simulate physical and biogeochemical properties at time scales of a few weeks and to use the model to analyze ice algal bloom dynamics in different types of ice. Ocean and atmospheric forcing data and observations of the evolution of the sea ice properties collected from 18 April to 4 June 2015, during the Norwegian young sea ICE expedition, were used to test the CICE model. Our results show the following: (i) model performance is reasonable for sea ice thickness and bulk salinity; good for vertically resolved temperature, vertically averaged Chl a concentrations, and standing stocks; and poor for vertically resolved Chl a concentrations. (ii) Improving current knowledge about nutrient exchanges, ice algal recruitment, and motion is critical to improve sea ice biogeochemical modeling. (iii) Ice algae may bloom despite some degree of basal melting. (iv) Ice algal motility driven by gradients in limiting factors is a plausible mechanism to explain their vertical distribution. (v) Different ice algal bloom and net primary production (NPP) patterns were identified in the ice types studied, suggesting that ice algal maximal growth rates will increase, while sea ice vertically integrated NPP and biomass will decrease as a result of the predictable increase in the area covered by refrozen leads in the Arctic Ocean.

  2. Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean

    NARCIS (Netherlands)

    Gazeau, F.; van Rijswijk, P.; Pozzato, L.; Middelburg, J.J.

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer

  3. Impacts of Ocean Acidification on Sediment Processes in Shallow Waters of the Arctic Ocean

    NARCIS (Netherlands)

    Gazeau, F.; van Rijswijk, P.; Pozzato, L.; Middelburg, J.J.

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer

  4. Regional variations in provenance and abundance of ice-rafted clasts in Arctic Ocean sediments: Implications for the configuration of late Quaternary oceanic and atmospheric circulation in the Arctic

    Science.gov (United States)

    Phillips, R.L.; Grantz, A.

    2001-01-01

    The composition and distribution of ice-rafted glacial erratics in late Quaternary sediments define the major current systems of the Arctic Ocean and identify two distinct continental sources for the erratics. In the southern Amerasia basin up to 70% of the erratics are dolostones and limestones (the Amerasia suite) that originated in the carbonate-rich Paleozoic terranes of the Canadian Arctic Islands. These clasts reached the Arctic Ocean in glaciers and were ice-rafted to the core sites in the clockwise Beaufort Gyre. The concentration of erratics decreases northward by 98% along the trend of the gyre from southeastern Canada basin to Makarov basin. The concentration of erratics then triples across the Makarov basin flank of Lomonosov Ridge and siltstone, sandstone and siliceous clasts become dominant in cores from the ridge and the Eurasia basin (the Eurasia suite). The bedrock source for the siltstone and sandstone clasts is uncertain, but bedrock distribution and the distribution of glaciation in northern Eurasia suggest the Taymyr Peninsula-Kara Sea regions. The pattern of clast distribution in the Arctic Ocean sediments and the sharp northward decrease in concentration of clasts of Canadian Arctic Island provenance in the Amerasia basin support the conclusion that the modem circulation pattern of the Arctic Ocean, with the Beaufort Gyre dominant in the Amerasia basin and the Transpolar drift dominant in the Eurasia basin, has controlled both sea-ice and glacial iceberg drift in the Arctic Ocean during interglacial intervals since at least the late Pleistocene. The abruptness of the change in both clast composition and concentration on the Makarov basin flank of Lomonosov Ridge also suggests that the boundary between the Beaufort Gyre and the Transpolar Drift has been relatively stable during interglacials since that time. Because the Beaufort Gyre is wind-driven our data, in conjunction with the westerly directed orientation of sand dunes that formed during

  5. Reconstruction of the Arctic Ocean environment during the Eocene Azolla interval using geochemical proxies and climate modeling. Geologica Ultraiectina (331)

    NARCIS (Netherlands)

    Speelman, E.N.

    2010-01-01

    With the realization that the Arctic Ocean was covered with enormous quantities of the aquatic floating fern Azolla 49 Myrs ago, new questions regarding the Eocene conditions facilitating these blooms arose. This dissertation describes the reconstruction of paleo-environmental conditions

  6. Sea surface height determination in the arctic ocean from Cryosat2 SAR data, the impact of using different empirical retrackers

    DEFF Research Database (Denmark)

    Jain, Maulik; Andersen, Ole Baltazar; Stenseng, Lars

    2012-01-01

    Cryosat2 Level 1B SAR data can be processed using different empirical retrackers to determine the sea surface height and its variations in the Arctic Ocean. Two improved retrackers based on the combination of OCOG (Offset Centre of Gravity), Threshold methods and Leading Edge Retrieval is used...

  7. Late quaternary palaeo-oceanography and palaeo-climatology from sediment cores of the eastern Arctic Ocean

    International Nuclear Information System (INIS)

    Pagels, U.; Koehler, S.

    1991-01-01

    Box cores recovered along a N-S transect in the Eurasian Basin allow the establishment of a time scale for the Late Quaternary history of the Arctic Ocean, based on stable oxygen isotope stratigraphy and AMS 14 C dating of planktonic foraminifers (N. pachyderma I.c.). This high resolution stratigraphy, in combination with sedimentological investigations (e.g. coarse fraction analysis, carbonate content, productivity of foraminifers), was carried out to reconstruct the glacial and inter-glacial Arctic Ocean palaeo-environment The sediment cores, which can be correlated throughout the sampling area in the Eastern Arctic Ocean, were dated as representing oxygen isotope stages 1 to 4/5. The sedimentation rates varied between a few mm/ka in glacials and approximately one cm/ka during the Holocene. The sediments allow a detailed sedimentological description of the depositional regime and the palaeo-oceanography of the Eastern Arctic Ocean. Changing ratios of biogenic and lithogenic components in the sediments reflect variations in the oceanographic circulation pattern in the Eurasian Basin during the Late Quaternary. Carbonate content (1-9wt.%), productivity of foraminifers (high in interglacial, low in glacial stages) and the terrigenous components are in good correlation with glacial and inter-glacial climatic fluctuations

  8. Organic Fe speciation in the Eurasian Basins of the Arctic Ocean and its relation to terrestrial DOM

    NARCIS (Netherlands)

    Slagter, H.A.; Reader, H.E.; Rijkenberg, M.J.A.; Rutgers van der Loeff, M.; de Baar, H.J.W.; Gerringa, L.J.A.

    2017-01-01

    The bio-essential trace metal iron (Fe) has poor inorganic solubility in seawater, and therefore dissolution is dependent on organic complexation. The Arctic Ocean is subject to strong terrestrial influences which contribute to organic solubility of Fe, particularly in the surface. These influences

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

    Data.gov (United States)

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

  10. Numerical simulation of vertical transport and oxidation of methane in Arctic Ocean

    Science.gov (United States)

    Stepanenko, Victor; Iakovlev, Nikolai

    2013-04-01

    The high abundance of methane in shelf of East Siberian Arctic Seas (ESAS) has been a subject of a number of field studies (e.g. Shakhova et al., 2010). This experimental evidence provoked discussions on probable origins of that methane and possible feedbacks to modern climate change. For instance, the hypothesis of methane hydrates degradation under current ocean warming was tested recently in several modeling studies none of which supported this degradation to be significant feedback for climate change. Regardless the origin of methane the knowledge of its budget in the water column is important to link its bottom flux with emission to the atmosphere (and vice versa). It is frequently assumed that all methane released from a seabed of ESAS shelf reaches the atmosphere. When using ocean circulation models (Biastoch et al., 2011) this simplification is cancelled out but the vertical resolution of 3D models at the shelf (that is several tens meters deep) is not enough to accurately resolve turbulent transport of methane and other gases. Moreover, up the knowledge of authors none of the ocean models includes explicitly bubble transport of gases. These constrains motivate this study. In this study a high-resolution 1D single column ocean model is constructed to explicitly simulate the methane transport, oxidation and emission to the atmosphere. The model accounts for both vertical turbulent transport (using k-ɛ closure) and bubble transport of gases. The ground under the seabed is represented by multilayer heat and moisture transfer model, including methane hydrate evolution. It is forced by time series of atmospheric variables from NCEP reanalysis and horizontal advection terms taken from FEMAO-1 3D ocean model. The baseline simulation is performed for the period 1948-2011. The model is validated using temperature profiles measured at research vessels in ESAS. The annual cycle and multiyear variability of methane profiles in water are studied and compared to

  11. The open-ocean sensible heat flux and its significance for Arctic boundary layer mixing during early fall

    Science.gov (United States)

    Ganeshan, Manisha; Wu, Dong L.

    2016-10-01

    The increasing ice-free area during late summer has transformed the Arctic to a climate system with more dynamic boundary layer (BL) clouds and seasonal sea ice growth. The open-ocean sensible heat flux, a crucial mechanism of excessive ocean heat loss to the atmosphere during the fall freeze season, is speculated to play an important role in the recently observed cloud cover increase and BL instability. However, lack of observations and understanding of the resilience of the proposed mechanisms, especially in relation to meteorological and interannual variability, has left a poorly constrained BL parameterization scheme in Arctic climate models. In this study, we use multi-year Japanese cruise-ship observations from R/V Mirai over the open Arctic Ocean to characterize the surface sensible heat flux (SSHF) during early fall and investigate its contribution to BL turbulence. It is found that mixing by SSHF is favored during episodes of high surface wind speed and is also influenced by the prevailing cloud regime. The deepest BLs and maximum ocean-atmosphere temperature difference are observed during cold air advection (associated with the stratocumulus regime), yet, contrary to previous speculation, the efficiency of sensible heat exchange is low. On the other hand, the SSHF contributes significantly to BL mixing during the uplift (low pressure) followed by the highly stable (stratus) regime. Overall, it can explain ˜ 10 % of the open-ocean BL height variability, whereas cloud-driven (moisture and radiative) mechanisms appear to be the other dominant source of convective turbulence. Nevertheless, there is strong interannual variability in the relationship between the SSHF and the BL height which can be intensified by the changing occurrence of Arctic climate patterns, such as positive surface wind speed anomalies and more frequent conditions of uplift. This study highlights the need for comprehensive BL observations like the R/V Mirai for better understanding and

  12. The Open-Ocean Sensible Heat Flux and Its Significance for Arctic Boundary Layer Mixing During Early Fall

    Science.gov (United States)

    Ganeshan, Manisha; Wu, Dongliang

    2016-01-01

    The increasing ice-free area during late summer has transformed the Arctic to a climate system with more dynamic boundary layer (BL) clouds and seasonal sea ice growth. The open-ocean sensible heat flux, a crucial mechanism of excessive ocean heat loss to the atmosphere during the fall freeze season, is speculated to play an important role in the recently observed cloud cover increase and BL instability. However, lack of observations and understanding of the resilience of the proposed mechanisms, especially in relation to meteorological and interannual variability, has left a poorly constrained BL parameterization scheme in Arctic climate models. In this study, we use multiyear Japanese cruise-ship observations from RV Mirai over the open Arctic Ocean to characterize the surface sensible heat flux (SSHF) during early fall and investigate its contribution to BL turbulence. It is found that mixing by SSHF is favored during episodes of high surface wind speed and is also influenced by the prevailing cloud regime. The deepest BLs and maximum ocean-atmosphere temperature difference are observed during cold air advection (associated with the stratocumulus regime), yet, contrary to previous speculation, the efficiency of sensible heat exchange is low. On the other hand, the SSHF contributes significantly to BL mixing during the uplift (low pressure) followed by the highly stable (stratus) regime. Overall, it can explain 10 of the open ocean BL height variability, whereas cloud-driven (moisture and radiative) mechanisms appear to be the other dominant source of convective turbulence. Nevertheless, there is strong interannual variability in the relationship between the SSHF and the BL height which can be intensified by the changing occurrence of Arctic climate patterns, such as positive surface wind speed anomalies and more frequent conditions of uplift. This study highlights the need for comprehensive BL observations like the RV Mirai for better understanding and

  13. Baseline monitoring of the western Arctic Ocean estimates 20% of Canadian basin surface waters are undersaturated with respect to aragonite.

    Directory of Open Access Journals (Sweden)

    Lisa L Robbins

    Full Text Available Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index for the western Arctic Ocean. This data set documents aragonite undersaturation in ≈ 20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean's largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater.

  14. Future ocean acidification in the Canada Basin and surrounding Arctic Ocean from CMIP5 earth system models

    Science.gov (United States)

    Steiner, N. S.; Christian, J. R.; Six, K. D.; Yamamoto, A.; Yamamoto-Kawai, M.

    2014-01-01

    Six Earth system models that include an interactive carbon cycle and have contributed results to the 5th Coupled Model Intercomparison Project (CMIP5) are evaluated with respect to Arctic Ocean acidification. Projections under Representative Concentration Pathways (RCPs) 8.5 and 4.5 consistently show reductions in the bidecadal mean surface pH from about 8.1 in 1986-2005 to 7.7/7.9 by 2066-2085 in the Canada Basin, closely linked to reductions in the calcium carbonate saturation state ΩA,C from about 1.4 (2.0) to 0.7 (1.0) for aragonite (calcite) for RCP8.5. The large but opposite effects of dilution and biological drawdown of DIC and dilution of alkalinity lead to a small seasonal amplitude change in Ω, as well as intermodel differences in the timing and sign of the summer minimum. The Canada Basin shows a characteristic layering in Ω: affected by ice melt and inflowing Pacific water, shallow undersaturated layers form at the surface and subsurface, creating a shallow saturation horizon which expands from the surface downward. This is in addition to the globally observed deep saturation horizon which is continuously expanding upward with increasing CO2 uptake. The Eurasian Basin becomes undersaturated much later than the rest of the Arctic. These CMIP5 model results strengthen earlier findings, although large intermodel differences remain: Below 200 m ΩA varies by up to 1.0 in the Canada Basin and the deep saturation horizon varies from 2000 to 4000 m among the models. Differences of projected acidification changes are primarily related to sea ice retreat and responses of wind mixing and stratification.

  15. The not-so-silent world: Measuring Arctic, Equatorial, and Antarctic soundscapes in the Atlantic Ocean

    Science.gov (United States)

    Haver, Samara M.; Klinck, Holger; Nieukirk, Sharon L.; Matsumoto, Haru; Dziak, Robert P.; Miksis-Olds, Jennifer L.

    2017-04-01

    Anthropogenic noise in the ocean has been shown, under certain conditions, to influence the behavior and health of marine mammals. Noise from human activities may interfere with the low-frequency acoustic communication of many Mysticete species, including blue (Balaenoptera musculus) and fin whales (B. physalus). This study analyzed three soundscapes in the Atlantic Ocean, from the Arctic to the Antarctic, to document ambient sound. For 16 months beginning in August 2009, acoustic data (15-100 Hz) were collected in the Fram Strait (79°N, 5.5°E), near Ascension Island (8°S, 14.4°W) and in the Bransfield Strait (62°S, 55.5°W). Results indicate (1) the highest overall sound levels were measured in the equatorial Atlantic, in association with high levels of seismic oil and gas exploration, (2) compared to the tropics, ambient sound levels in polar regions are more seasonally variable, and (3) individual elements beget the seasonal and annual variability of ambient sound levels in high latitudes. Understanding how the variability of natural and man-made contributors to sound may elicit differences in ocean soundscapes is essential to developing strategies to manage and conserve marine ecosystems and animals.

  16. Arctic Ocean UNCLOS Article 76 Work for Greenland Starts on Land

    Science.gov (United States)

    Dahl-Jensen, T.; Marcussen, C.; Jackson, R.; Voss, P.

    2005-12-01

    One of the most lonely and desolate stretches of coastline on the planet has become the target for UNCLOS article 76 related research. The Danish Continental Shelf Project has launched a work program to investigate the possibilities for Greenland to claim an area outside the 200 nm limit in the Arctic Ocean. The role of the Lomonosov Ridge as a Natural Prolongation of Greenland/Canada is an important issue, and in order to better evaluate the connection between Greenland and the Lomonosov Ridge the nature of not only the ridge but also of Northern Greenland is the target of deep crustal investigations. The North Greenland Fold belt covers the ice-free part of North Greenland and continues west in the Canadian Arctic. The foldbelt was formed during the Ellesmerian orogeny, where sediments from the Franklinian Basin where compressed and deformed. The deep structure of basin and its subsequent closure are broadly unknown. Three broad band earthquake seismological stations where installed in North Greenland to supplement the existing stations at Alert (Canada) and Station Nord to the east, and the first data was available summer 2005. Crustal thickness data from these first results are presented. Plans for the spring 2006 consist of wide-angle acquisition on the sea ice from the Greenland-Canadian mainland out onto the Lomonosov Ridge, a joint Danish - Canadian project with a 400 km long profile over difficult ice conditions, 18 tons of explosives, three helicopters, a Twin Otter and about 30 participants.

  17. 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)

    2016-07-27

    impacts on sea-ice and water properties in the Chukchi and Beaufort Seas and western Arctic Ocean for 2013-2014 Rebecca Woodgate Polar Science...and G. R. Bigg (2002), Impact of flow through the Canadian Archipelago and Bering Strait on the North Atlantic and Arctic circulation: an ocean ...Technical 3. DATES COVERED (From - To) Feb 2013 - April 2016 4. TITLE AND SUBTITLE Quantifying the Bering Strait oceanic fluxes and their impacts

  18. Wintertime Arctic Ocean sea water properties and primary marine aerosol concentrations

    Directory of Open Access Journals (Sweden)

    J. Zábori

    2012-11-01

    Full Text Available Sea spray aerosols are an important part of the climate system through their direct and indirect effects. Due to the diminishing sea ice, the Arctic Ocean is one of the most rapidly changing sea spray aerosol source areas. However, the influence of these changes on primary particle production is not known.

    In laboratory experiments we examined the influence of Arctic Ocean water temperature, salinity, and oxygen saturation on primary particle concentration characteristics. Sea water temperature was identified as the most important of these parameters. A strong decrease in sea spray aerosol production with increasing water temperature was observed for water temperatures between −1°C and 9°C. Aerosol number concentrations decreased from at least 1400 cm−3 to 350 cm−3. In general, the aerosol number size distribution exhibited a robust shape with one mode close to dry diameter Dp 0.2 μm with approximately 45% of particles at smaller sizes. Changes in sea water temperature did not result in pronounced change of the shape of the aerosol size distribution, only in the magnitude of the concentrations. Our experiments indicate that changes in aerosol emissions are most likely linked to changes of the physical properties of sea water at low temperatures. The observed strong dependence of sea spray aerosol concentrations on sea water temperature, with a large fraction of the emitted particles in the typical cloud condensation nuclei size range, provide strong arguments for a more careful consideration of this effect in climate models.

  19. Active spreading processes at ultraslow mid-ocean ridges: The 1999-2001 seismo-volcanic episode at 85°E Gakkel ridge, Arctic Ocean

    Science.gov (United States)

    Schlindwein, Vera; Riedel, Carsten; Korger, Edith; Läderach, Christine

    2010-05-01

    seismicity migration, the swarm activated the rift valley boundary faults in a large area. Along the entire Gakkel ridge, normal fault earthquakes occur predominantly at volcanic centres pointing to strong tectonomagmatic interplay. - unusual change in swarm characteristics: Following 2-3 months of predominantly tectonic faulting, the swarm displays increasing non-double couple character events and an abrupt change in event rate preceded by three conspicuous events of high similarity located in the vicinity of potentially active volcanic structures. Brittle faulting may thus trigger later volcanic discharge or it could be in turn triggered by rising melts. - unusual volcanic discharge: In 2007, Sohn et al. (2008) discovered abundant pyroclastic deposits containing limu o Pele at the 85°E volcanic complex and therefore postulated recent deep submarine explosive volcanism at this site. In order to drive these explosive eruptions at 4 km water depth, high volume fractions of magmatic volatiles must be accumulated locally, for example at the top of a magma chamber under a thick and stable lithospheric roof. Together with the Strombolian eruptions which we inferred from the seismoacoustic explosion signals recorded in 2001, this indicates that an explosive eruption style may be common for volcanic spreading events at ultraslow spreading ridges. Sohn et al. (2008), Explosive volcanism on the ultraslow-spreading Gakkel Ridge, Arctic Ocean, Nature, 453,doi:10.1038/nature07075.

  20. An Arctic source for the Great Salinity Anomaly - A simulation of the Arctic ice-ocean system for 1955-1975

    Science.gov (United States)

    Hakkinen, Sirpa

    1993-01-01

    The paper employs a fully prognostic Arctic ice-ocean model to study the interannual variability of sea ice during the period 1955-1975 and to explain the large variability of the ice extent in the Greenland and Iceland seas during the late 1960s. The model is used to test the contention of Aagaard and Carmack (1989) that the Great Salinity Anomaly (GSA) was a consequence of the anomalously large ice export in 1968. The high-latitude ice-ocean circulation changes due to wind field changes are explored. The ice export event of 1968 was the largest in the simulation, being about twice as large as the average and corresponding to 1600 cu km of excess fresh water. The simulations suggest that, besides the above average ice export to the Greenland Sea, there was also fresh water export to support the larger than average ice cover. The model results show the origin of the GSA to be in the Arctic, and support the view that the Arctic may play an active role in climate change.

  1. Ice–ocean coupled computations for sea-ice prediction to support ice navigation in Arctic sea routes

    Directory of Open Access Journals (Sweden)

    Liyanarachchi Waruna Arampath De Silva

    2015-11-01

    Full Text Available With the recent rapid decrease in summer sea ice in the Arctic Ocean extending the navigation period in the Arctic sea routes (ASR, the precise prediction of ice distribution is crucial for safe and efficient navigation in the Arctic Ocean. In general, however, most of the available numerical models have exhibited significant uncertainties in short-term and narrow-area predictions, especially in marginal ice zones such as the ASR. In this study, we predict short-term sea-ice conditions in the ASR by using a mesoscale eddy-resolving ice–ocean coupled model that explicitly treats ice floe collisions in marginal ice zones. First, numerical issues associated with collision rheology in the ice–ocean coupled model (ice–Princeton Ocean Model [POM] are discussed and resolved. A model for the whole of the Arctic Ocean with a coarser resolution (about 25 km was developed to investigate the performance of the ice–POM model by examining the reproducibility of seasonal and interannual sea-ice variability. It was found that this coarser resolution model can reproduce seasonal and interannual sea-ice variations compared to observations, but it cannot be used to predict variations over the short-term, such as one to two weeks. Therefore, second, high-resolution (about 2.5 km regional models were set up along the ASR to investigate the accuracy of short-term sea-ice predictions. High-resolution computations were able to reasonably reproduce the sea-ice extent compared to Advanced Microwave Scanning Radiometer–Earth Observing System satellite observations because of the improved expression of the ice–albedo feedback process and the ice–eddy interaction process.

  2. Large-scale temperature and salinity changes in the upper Canadian Basin of the Arctic Ocean at a time of a drastic Arctic Oscillation inversion

    Directory of Open Access Journals (Sweden)

    P. Bourgain

    2013-04-01

    Full Text Available Between 2008 and 2010, the Arctic Oscillation index over Arctic regions shifted from positive values corresponding to more cyclonic conditions prevailing during the 4th International Polar Year (IPY period (2007–2008 to extremely negative values corresponding to strong anticyclonic conditions in 2010. In this context, we investigated the recent large-scale evolution of the upper western Arctic Ocean, based on temperature and salinity summertime observations collected during icebreaker campaigns and from ice-tethered profilers (ITPs drifting across the region in 2008 and 2010. Particularly, we focused on (1 the freshwater content which was extensively studied during previous years, (2 the near-surface temperature maximum due to incoming solar radiation, and (3 the water masses advected from the Pacific Ocean into the Arctic Ocean. The observations revealed a freshwater content change in the Canadian Basin during this time period. South of 80° N, the freshwater content increased, while north of 80° N, less freshening occurred in 2010 compared to 2008. This was more likely due to the strong anticyclonicity characteristic of a low AO index mode that enhanced both a wind-generated Ekman pumping in the Beaufort Gyre and a possible diversion of the Siberian River runoff toward the Eurasian Basin at the same time. The near-surface temperature maximum due to incoming solar radiation was almost 1 °C colder in the southern Canada Basin (south of 75° N in 2010 compared to 2008, which contrasted with the positive trend observed during previous years. This was more likely due to higher summer sea ice concentration in 2010 compared to 2008 in that region, and surface albedo feedback reflecting more sun radiation back in space. The Pacific water (PaW was also subjected to strong spatial and temporal variability between 2008 and 2010. In the Canada Basin, both summer and winter PaW signatures were stronger between 75° N and 80° N. This was more likely

  3. Poles Apart: The “Bipolar” Pteropod Species Limacina helicina Is Genetically Distinct Between the Arctic and Antarctic Oceans

    Science.gov (United States)

    Bednarsek, Nina; Linse, Katrin; Nelson, R. John; Pakhomov, Evgeny; Seibel, Brad; Steinke, Dirk; Würzberg, Laura

    2010-01-01

    The shelled pteropod (sea butterfly) Limacina helicina is currently recognised as a species complex comprising two sub-species and at least five “forma”. However, at the species level it is considered to be bipolar, occurring in both the Arctic and Antarctic oceans. Due to its aragonite shell and polar distribution L. helicina is particularly vulnerable to ocean acidification. As a key indicator of the acidification process, and a major component of polar ecosystems, L. helicina has become a focus for acidification research. New observations that taxonomic groups may respond quite differently to acidification prompted us to reassess the taxonomic status of this important species. We found a 33.56% (±0.09) difference in cytochrome c oxidase subunit I (COI) gene sequences between L. helicina collected from the Arctic and Antarctic oceans. This degree of separation is sufficient for ordinal level taxonomic separation in other organisms and provides strong evidence for the Arctic and Antarctic populations of L. helicina differing at least at the species level. Recent research has highlighted substantial physiological differences between the poles for another supposedly bipolar pteropod species, Clione limacina. Given the large genetic divergence between Arctic and Antarctic L. helicina populations shown here, similarly large physiological differences may exist between the poles for the L. helicina species group. Therefore, in addition to indicating that L. helicina is in fact not bipolar, our study demonstrates the need for acidification research to take into account the possibility that the L. helicina species group may not respond in the same way to ocean acidification in Arctic and Antarctic ecosystems. PMID:20360985

  4. Poles apart: the "bipolar" pteropod species Limacina helicina is genetically distinct between the Arctic and Antarctic oceans.

    Science.gov (United States)

    Hunt, Brian; Strugnell, Jan; Bednarsek, Nina; Linse, Katrin; Nelson, R John; Pakhomov, Evgeny; Seibel, Brad; Steinke, Dirk; Würzberg, Laura

    2010-03-23

    The shelled pteropod (sea butterfly) Limacina helicina is currently recognised as a species complex comprising two sub-species and at least five "forma". However, at the species level it is considered to be bipolar, occurring in both the Arctic and Antarctic oceans. Due to its aragonite shell and polar distribution L. helicina is particularly vulnerable to ocean acidification. As a key indicator of the acidification process, and a major component of polar ecosystems, L. helicina has become a focus for acidification research. New observations that taxonomic groups may respond quite differently to acidification prompted us to reassess the taxonomic status of this important species. We found a 33.56% (+/-0.09) difference in cytochrome c oxidase subunit I (COI) gene sequences between L. helicina collected from the Arctic and Antarctic oceans. This degree of separation is sufficient for ordinal level taxonomic separation in other organisms and provides strong evidence for the Arctic and Antarctic populations of L. helicina differing at least at the species level. Recent research has highlighted substantial physiological differences between the poles for another supposedly bipolar pteropod species, Clione limacina. Given the large genetic divergence between Arctic and Antarctic L. helicina populations shown here, similarly large physiological differences may exist between the poles for the L. helicina species group. Therefore, in addition to indicating that L. helicina is in fact not bipolar, our study demonstrates the need for acidification research to take into account the possibility that the L. helicina species group may not respond in the same way to ocean acidification in Arctic and Antarctic ecosystems.

  5. The open-ocean sensible heat flux and its significance for Arctic boundary layer mixing during early fall

    Directory of Open Access Journals (Sweden)

    M. Ganeshan

    2016-10-01

    Full Text Available The increasing ice-free area during late summer has transformed the Arctic to a climate system with more dynamic boundary layer (BL clouds and seasonal sea ice growth. The open-ocean sensible heat flux, a crucial mechanism of excessive ocean heat loss to the atmosphere during the fall freeze season, is speculated to play an important role in the recently observed cloud cover increase and BL instability. However, lack of observations and understanding of the resilience of the proposed mechanisms, especially in relation to meteorological and interannual variability, has left a poorly constrained BL parameterization scheme in Arctic climate models. In this study, we use multi-year Japanese cruise-ship observations from R/V Mirai over the open Arctic Ocean to characterize the surface sensible heat flux (SSHF during early fall and investigate its contribution to BL turbulence. It is found that mixing by SSHF is favored during episodes of high surface wind speed and is also influenced by the prevailing cloud regime. The deepest BLs and maximum ocean–atmosphere temperature difference are observed during cold air advection (associated with the stratocumulus regime, yet, contrary to previous speculation, the efficiency of sensible heat exchange is low. On the other hand, the SSHF contributes significantly to BL mixing during the uplift (low pressure followed by the highly stable (stratus regime. Overall, it can explain  ∼  10 % of the open-ocean BL height variability, whereas cloud-driven (moisture and radiative mechanisms appear to be the other dominant source of convective turbulence. Nevertheless, there is strong interannual variability in the relationship between the SSHF and the BL height which can be intensified by the changing occurrence of Arctic climate patterns, such as positive surface wind speed anomalies and more frequent conditions of uplift. This study highlights the need for comprehensive BL observations like the R/V Mirai for

  6. Investigating the role of wind in generating surface currents over the slope area of the Laptev Sea, Arctic Ocean

    Science.gov (United States)

    Patteson, R. N.

    2017-12-01

    Mixing mechanisms of the Arctic Ocean have profound impacts on sea ice, global ocean dynamics, and arctic communities. This project used a two-year long time series of ocean current velocities collected from eight moorings located on the Eurasian basin, as well as ERA-interim wind data, to compare and assess relationships between current and wind velocities at different depths. Determining the strength of these correlations will further scientific understanding of the degree to which wind influences mixing, with implications for heat flux, diffusion, and sea ice changes. Using statistical analysis, I calculated whether a significant relationship between wind velocity and ocean currents existed beginning at the surface level ( 50m) .The final correlation values, ranging from R = 0.11 to R = 0.28, indicated a weak relationship between wind velocity and ocean currents at the surface for all eight mooring sites. The results for the surface depth imply that correlation likely decreases with increasing depths, and thus further testing of deeper depth levels was unnecessary. This finding suggests that there is another dominant factor at play in the ocean; we postulate that topography exerts a significant influence on subsurface mixing. This study highlights the need for further research of the different mechanisms and their importance in influencing the dynamic structure of the ocean.

  7. The Potential and Challenges of Using Soil Moisture Active Passive (SMAP Sea Surface Salinity to Monitor Arctic Ocean Freshwater Changes

    Directory of Open Access Journals (Sweden)

    Wenqing Tang

    2018-06-01

    Full Text Available Sea surface salinity (SSS links various components of the Arctic freshwater system. SSS responds to freshwater inputs from river discharge, sea ice change, precipitation and evaporation, and oceanic transport through the open straits of the Pacific and Atlantic oceans. However, in situ SSS data in the Arctic Ocean are very sparse and insufficient to depict the large-scale variability to address the critical question of how climate variability and change affect the Arctic Ocean freshwater. The L-band microwave radiometer on board the NASA Soil Moisture Active Passive (SMAP mission has been providing SSS measurements since April 2015, at approximately 60 km resolution with Arctic Ocean coverage in 1–2 days. With improved land/ice correction, the SMAP SSS algorithm that was developed at the Jet Propulsion Laboratory (JPL is able to retrieve SSS in ice-free regions 35 km of the coast. SMAP observes a large-scale contrast in salinity between the Atlantic and Pacific sides of the Arctic Ocean, while retrievals within the Arctic Circle vary over time, depending on the sea ice coverage and river runoff. We assess the accuracy of SMAP SSS through comparative analysis with in situ salinity data collected by Argo floats, ships, gliders, and in field campaigns. Results derived from nearly 20,000 pairs of SMAP and in situ data North of 50°N collocated within a 12.5-km radius and daily time window indicate a Root Mean Square Difference (RMSD less than ~1 psu with a correlation coefficient of 0.82 and a near unity regression slope over the entire range of salinity. In contrast, the Hybrid Coordinate Ocean Model (HYCOM has a smaller RMSD with Argo. However, there are clear systematic biases in the HYCOM for salinity in the range of 25–30 psu, leading to a regression slope of about 0.5. In the region North of 65°N, the number of collocated samples drops more than 70%, resulting in an RMSD of about 1.2 psu. SMAP SSS in the Kara Sea shows a consistent

  8. Transport of contaminants by Arctic sea ice and surface ocean currents

    International Nuclear Information System (INIS)

    Pfirman, S.

    1995-01-01

    Sea ice and ocean currents transport contaminants in the Arctic from source areas on the shelves, to biologically active regions often more than a thousand kilometers away. Coastal regions along the Siberian margin are polluted by discharges of agricultural, industrial and military wastes in river runoff, from atmospheric deposition and ocean dumping. The Kara Sea is of particular concern because of deliberate dumping of radioactive waste, as well as the large input of polluted river water. Contaminants are incorporated in ice during suspension freezing on the shelves, and by atmospheric deposition during drift. Ice releases its contaminant load through brine drainage, surface runoff of snow and meltwater, and when the floe disintegrates. The marginal ice zone, a region of intense biological activity, may also be the site of major contaminant release. Potentially contaminated ice from the Kara Sea is likely to influence the marginal ice zones of the Barents and Greenland seas. From studies conducted to date it appears that sea ice from the Kara Sea does not typically enter the Beaufort Gyre, and thus is unlikely to affect the northern Canadian and Alaskan margins

  9. Improved ocean-color remote sensing in the Arctic using the POLYMER algorithm

    Science.gov (United States)

    Frouin, Robert; Deschamps, Pierre-Yves; Ramon, Didier; Steinmetz, François

    2012-10-01

    Atmospheric correction of ocean-color imagery in the Arctic brings some specific challenges that the standard atmospheric correction algorithm does not address, namely low solar elevation, high cloud frequency, multi-layered polar clouds, presence of ice in the field-of-view, and adjacency effects from highly reflecting surfaces covered by snow and ice and from clouds. The challenges may be addressed using a flexible atmospheric correction algorithm, referred to as POLYMER (Steinmetz and al., 2011). This algorithm does not use a specific aerosol model, but fits the atmospheric reflectance by a polynomial with a non spectral term that accounts for any non spectral scattering (clouds, coarse aerosol mode) or reflection (glitter, whitecaps, small ice surfaces within the instrument field of view), a spectral term with a law in wavelength to the power -1 (fine aerosol mode), and a spectral term with a law in wavelength to the power -4 (molecular scattering, adjacency effects from clouds and white surfaces). Tests are performed on selected MERIS imagery acquired over Arctic Seas. The derived ocean properties, i.e., marine reflectance and chlorophyll concentration, are compared with those obtained with the standard MEGS algorithm. The POLYMER estimates are more realistic in regions affected by the ice environment, e.g., chlorophyll concentration is higher near the ice edge, and spatial coverage is substantially increased. Good retrievals are obtained in the presence of thin clouds, with ocean-color features exhibiting spatial continuity from clear to cloudy regions. The POLYMER estimates of marine reflectance agree better with in situ measurements than the MEGS estimates. Biases are 0.001 or less in magnitude, except at 412 and 443 nm, where they reach 0.005 and 0.002, respectively, and root-mean-squared difference decreases from 0.006 at 412 nm to less than 0.001 at 620 and 665 nm. A first application to MODIS imagery is presented, revealing that the POLYMER algorithm is

  10. Temperature, salinity, and nutrients data from CTD and bottle casts in the Arctic, North Atlantic and North Pacific Oceans from multiple platforms from 1963-04-30 to 1999-02-15 (NODC Accession 0000418)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD, bottle, and other data were collected from the Arctic Ocean, North Atlantic Ocean, and North Pacific from multiple platforms from 30 April 1963 to 15 February...

  11. Dissolved Fe in the Deep and Upper Arctic Ocean With a Focus on Fe Limitation in the Nansen Basin

    Directory of Open Access Journals (Sweden)

    Micha J. A. Rijkenberg

    2018-03-01

    Full Text Available Global warming resulting from the release of anthropogenic carbon dioxide is rapidly changing the Arctic Ocean. Over the last decade sea ice declined in extent and thickness. As a result, improved light availability has increased Arctic net primary production, including in under-ice phytoplankton blooms. During the GEOTRACES cruise PS94 in the summer of 2015 we measured dissolved iron (DFe, nitrate and phosphate throughout the central part of the Eurasian Arctic. In the deeper waters concentrations of DFe were higher, which we relate to resuspension on the continental slope in the Nansen Basin and hydrothermal activity at the Gakkel Ridge. The main source of DFe in the surface was the Trans Polar Drift (TPD, resulting in concentrations up to 4.42 nM. Nevertheless, using nutrient ratios we show that a large under-ice bloom in the Nansen basin was limited by Fe. Fe limitation potentially prevented up to 54% of the available nitrate and nitrite from being used for primary production. In the Barents Sea, Fe is expected to be the first nutrient to be depleted as well. Changes in the Arctic biogeochemical cycle of Fe due to retreating ice may therefore have large consequences for primary production, the Arctic ecosystem and the subsequent drawdown of carbon dioxide.

  12. Moonlight Drives Ocean-Scale Mass Vertical Migration of Zooplankton during the Arctic Winter.

    Science.gov (United States)

    Last, Kim S; Hobbs, Laura; Berge, Jørgen; Brierley, Andrew S; Cottier, Finlo

    2016-01-25

    In extreme high-latitude marine environments that are without solar illumination in winter, light-mediated patterns of biological migration have historically been considered non-existent [1]. However, diel vertical migration (DVM) of zooplankton has been shown to occur even during the darkest part of the polar night, when illumination levels are exceptionally low [2, 3]. This paradox is, as yet, unexplained. Here, we present evidence of an unexpected uniform behavior across the entire Arctic, in fjord, shelf, slope and open sea, where vertical migrations of zooplankton are driven by lunar illumination. A shift from solar-day (24-hr period) to lunar-day (24.8-hr period) vertical migration takes place in winter when the moon rises above the horizon. Further, mass sinking of zooplankton from the surface waters and accumulation at a depth of ∼50 m occurs every 29.5 days in winter, coincident with the periods of full moon. Moonlight may enable predation of zooplankton by carnivorous zooplankters, fish, and birds now known to feed during the polar night [4]. Although primary production is almost nil at this time, lunar vertical migration (LVM) may facilitate monthly pulses of carbon remineralization, as they occur continuously in illuminated mesopelagic systems [5], due to community respiration of carnivorous and detritivorous zooplankton. The extent of LVM during the winter suggests that the behavior is highly conserved and adaptive and therefore needs to be considered as "baseline" zooplankton activity in a changing Arctic ocean [6-9]. VIDEO ABSTRACT. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Quaternary Sea-ice history in the Arctic Ocean based on a new Ostracode sea-ice proxy

    Science.gov (United States)

    Cronin, T. M.; Gemery, L.; Briggs, W.M.; Jakobsson, M.; Polyak, L.; Brouwers, E.M.

    2010-01-01

    Paleo-sea-ice history in the Arctic Ocean was reconstructed using the sea-ice dwelling ostracode Acetabulastoma arcticum from late Quaternary sediments from the Mendeleyev, Lomonosov, and Gakkel Ridges, the Morris Jesup Rise and the Yermak Plateau. Results suggest intermittently high levels of perennial sea ice in the central Arctic Ocean during Marine Isotope Stage (MIS) 3 (25-45 ka), minimal sea ice during the last deglacial (16-11 ka) and early Holocene thermal maximum (11-5 ka) and increasing sea ice during the mid-to-late Holocene (5-0 ka). Sediment core records from the Iceland and Rockall Plateaus show that perennial sea ice existed in these regions only during glacial intervals MIS 2, 4, and 6. These results show that sea ice exhibits complex temporal and spatial variability during different climatic regimes and that the development of modern perennial sea ice may be a relatively recent phenomenon. ?? 2010.

  14. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Direct observations of atmosphere - sea ice - ocean interactions during Arctic winter and spring storms

    Science.gov (United States)

    Graham, R. M.; Itkin, P.; Granskog, M. A.; Assmy, P.; Cohen, L.; Duarte, P.; Doble, M. J.; Fransson, A.; Fer, I.; Fernandez Mendez, M.; Frey, M. M.; Gerland, S.; Haapala, J. J.; Hudson, S. R.; Liston, G. E.; Merkouriadi, I.; Meyer, A.; Muilwijk, M.; Peterson, A.; Provost, C.; Randelhoff, A.; Rösel, A.; Spreen, G.; Steen, H.; Smedsrud, L. H.; Sundfjord, A.

    2017-12-01

    To study the thinner and younger sea ice that now dominates the Arctic the Norwegian Young Sea ICE expedition (N-ICE2015) was launched in the ice-covered region north of Svalbard, from January to June 2015. During this time, eight local and remote storms affected the region and rare direct observations of the atmosphere, snow, ice and ocean were conducted. Six of these winter storms passed directly over the expedition and resulted in air temperatures rising from below -30oC to near 0oC, followed by abrupt cooling. Substantial snowfall prior to the campaign had already formed a snow pack of approximately 50 cm, to which the February storms contributed an additional 6 cm. The deep snow layer effectively isolated the ice cover and prevented bottom ice growth resulting in low brine fluxes. Peak wind speeds during winter storms exceeded 20 m/s, causing strong snow re-distribution, release of sea salt aerosol and sea ice deformation. The heavy snow load caused widespread negative freeboard; during sea ice deformation events, level ice floes were flooded by sea water, and at least 6-10 cm snow-ice layer was formed. Elevated deformation rates during the most powerful winter storms damaged the ice cover permanently such that the response to wind forcing increased by 60 %. As a result of a remote storm in April deformation processes opened about 4 % of the total area into leads with open water, while a similar amount of ice was deformed into pressure ridges. The strong winds also enhanced ocean mixing and increased ocean heat fluxes three-fold in the pycnocline from 4 to 12 W/m2. Ocean heat fluxes were extremely large (over 300 W/m2) during storms in regions where the warm Atlantic inflow is located close to surface over shallow topography. This resulted in very large (5-25 cm/day) bottom ice melt and in cases flooding due to heavy snow load. Storm events increased the carbon dioxide exchange between the atmosphere and ocean but also affected the pCO2 in surface waters

  16. Depositional History of the Western Amundsen Basin, Arctic Ocean, and Implications for Neogene Climate and Oceanographic Conditions

    Science.gov (United States)

    Hopper, J. R.; Castro, C. F.; Knutz, P. C.; Funck, T.

    2017-12-01

    Seismic reflection data collected in the western Amundsen Basin as part of the Law of the Sea program for the Kingdom of Denmark show a uniform and continuous cover of sediments over oceanic basement. An interpretation of seismic facies units shows that the depositional history of the basin reflects changing tectonic, climatic, and oceanographic conditions throughout the Cenozoic. In this contribution, the Miocene to present history is summarized. Two distinct changes in the depositional environment are proposed, first in response to the development of a deep water connection between the Arctic and North Atlantic, and the second in response to the onset of perennial sea ice cover in the Arctic. In the early to mid-Miocene, a buildup of contourite deposits indicates a distinct change in sedimentation that is particularly well developed near the flank of the Lomonosov Ridge. It is suggested that this is a response to the opening of the Fram Strait and the establishment of geostrophic bottom currents that flowed from the Laptev Sea towards Greenland. These deposits are overlain by a seismic facies unit characterized by buried channels and erosional features. These include prominent basinward levee systems that suggest a channel morphology maintained by overbank deposition of muddy sediments carried by suspension currents periodically spilling over the channel pathway. These deposits indicate a change to a much higher energy environment that is proposed to be a response to brine formation associated with the onset of perennial sea ice cover in the Arctic Ocean. This interpretation implies that the development of extensive sea ice cover results in a significant change in the energy environment of the ocean that is reflected in the depositional and erosional patterns observed. The lack of similar high energy erosional features and the presence of contourite deposits throughout most of the Miocene may indicate the Arctic Ocean was relatively ice-free until the very latest

  17. Dissolved methane in the Beaufort Sea and the Arctic Ocean, 1992–2009; sources and atmospheric flux

    NARCIS (Netherlands)

    Lorenson, T.D.; Greinert, J.; Coffin, R.B.

    2016-01-01

    Methane concentration and isotopic composition was measured in ice-covered and ice-free waters of theArctic Ocean during 11 surveys spanning the years of 1992–1995 and 2009. During ice-free periods, methaneflux from the Beaufort shelf varies from 0.14 mg CH4 m22 d21 to 0.43 mg CH4 m22 d21. Maximum

  18. Organic molecular composition of marine aerosols over the Arctic Ocean in summer: contributions of primary emission and secondary aerosol formation

    OpenAIRE

    P. Q. Fu; K. Kawamura; J. Chen; B. Charrière; R. Sempéré

    2013-01-01

    Organic molecular composition of marine aerosol samples collected during the MALINA cruise in the Arctic Ocean was investigated by gas chromatography/mass spectrometry. More than 110 individual organic compounds were determined in the samples and were grouped into different compound classes based on the functionality and sources. The concentrations of total quantified organics ranged from 7.3 to 185 ng m−3 (mean 47.6 ng m−3), accounting ...

  19. 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.

  20. Scientific Discoveries in the Central Arctic Ocean Based on Seafloor Mapping Carried out to Support Article 76 Extended Continental Shelf Claims (Invited)

    Science.gov (United States)

    Jakobsson, M.; Mayer, L. A.; Marcussen, C.

    2013-12-01

    Despite the last decades of diminishing sea-ice cover in the Arctic Ocean, ship operations are only possible in vast sectors of the central Arctic using the most capable polar-class icebreakers. There are less than a handful of these icebreakers outfitted with modern seafloor mapping equipment. This implies either fierce competition between those having an interest in using these icebreakers for investigations of the shape and properties of Arctic Ocean seafloor or, preferably, collaboration. In this presentation examples will be shown of scientific discoveries based on mapping data collected during Arctic Ocean icebreaker expeditions carried out for the purpose of substantiating claims for an extended continental shelf under United Nations Convention of the Law of the Sea (UNCLOS) Article 76. Scientific results will be presented from the suite of Lomonosov Ridge off Greenland (LOMROG) expeditions (2007, 2009, and 2012), shedding new light on Arctic Ocean oceanography and glacial history. The Swedish icebreaker Oden was used in collaboration between Sweden and Denmark during LOMROG to map and sample portions of the central Arctic Ocean; specifically focused on the Lomonosov Ridge north of Greenland. While the main objective of the Danish participation was seafloor and sub-seabed mapping to substantiate their Article 76 claim, LOMROG also included several scientific components, with scientists from both countries involved. Other examples to be presented are based on data collected using US Coast Guard Cutter Healy, which for several years has carried out mapping in the western Arctic Ocean for the US continental shelf program. All bathymetric data collected with Oden and Healy have been contributed to the International Bathymetric Chart of the Arctic Ocean (IBCAO). This is also the case for bathymetric data collected by Canadian Coast Guard Ship Louis S. St-Laurent for Canada's extended continental shelf claim. Together, the bathymetric data collected during these

  1. Anomalous Structure of Oceanic Lithosphere in the North Atlantic and Arctic Oceans: A Preliminary Analysis Based on Bathymetry, Gravity and Crustal Structure

    Science.gov (United States)

    Barantsrva, O.

    2014-12-01

    We present a preliminary analysis of the crustal and upper mantle structure for off-shore regions in the North Atlantic and Arctic oceans. These regions have anomalous oceanic lithosphere: the upper mantle of the North Atlantic ocean is affected by the Iceland plume, while the Arctic ocean has some of the slowest spreading rates. Our specific goal is to constrain the density structure of the upper mantle in order to understand the links between the deep lithosphere dynamics, ocean spreading, ocean floor bathymetry, heat flow and structure of the oceanic lithosphere in the regions where classical models of evolution of the oceanic lithosphere may not be valid. The major focus is on the oceanic lithosphere, but the Arctic shelves with a sufficient data coverage are also included into the analysis. Out major interest is the density structure of the upper mantle, and the analysis is based on the interpretation of GOCE satellite gravity data. To separate gravity anomalies caused by subcrustal anomalous masses, the gravitational effect of water, crust and the deep mantle is removed from the observed gravity field. For bathymetry we use the global NOAA database ETOPO1. The crustal correction to gravity is based on two crustal models: (1) global model CRUST1.0 (Laske, 2013) and, for a comparison, (2) a regional seismic model EUNAseis (Artemieva and Thybo, 2013). The crustal density structure required for the crustal correction is constrained from Vp data. Previous studies have shown that a large range of density values corresponds to any Vp value. To overcome this problem and to reduce uncertainty associated with the velocity-density conversion, we account for regional tectonic variations in the Northern Atlantics as constrained by numerous published seismic profiles and potential-field models across the Norwegian off-shore crust (e.g. Breivik et al., 2005, 2007), and apply different Vp-density conversions for different parts of the region. We present preliminary results

  2. Numerical investigations of the fluid flows at deep oceanic and arctic permafrost-associated gas hydrate deposits

    Science.gov (United States)

    Frederick, Jennifer Mary

    , allows us a unique opportunity to study the response of methane hydrate deposits to warming. Gas hydrate stability in the Arctic and the permeability of the shelf sediments to gas migration is thought to be closely linked with relict submarine permafrost. Submarine permafrost extent depends on several environmental factors, such as the shelf lithology, sea level variations, mean annual air temperature, ocean bottom water temperature, geothermal heat flux, groundwater hydrology, and the salinity of the pore water. Effects of submarine groundwater discharge, which introduces fresh terrestrial groundwater off-shore, can freshen deep marine sediments and is an important control on the freezing point depression of ice and methane hydrate. While several thermal modeling studies suggest the permafrost layer should still be largely intact near-shore, many recent field studies have reported elevated methane levels in Arctic coastal waters. The permafrost layer is thought to create an impermeable barrier to fluid and gas flow, however, talik formation (unfrozen regions within otherwise continuous permafrost) below paleo-river channels can create permeable pathways for gas migration from depth. This is the first study of its kind to make predictions of the methane gas flux to the water column from the Arctic shelf sediments using a 2D multi-phase fluid flow model. Model results show that the dissociation of methane hydrate deposits through taliks can supersaturate the overlying water column at present-day relative to equilibrium with the atmosphere when taliks are large (> 1 km width) or hydrate saturation is high within hydrate layers (> 50% pore volume). Supersaturated waters likely drive a net flux of methane into the atmosphere, a potent greenhouse gas. Effects of anthropogenic global warming will certainly increase gas venting rates if ocean bottom water temperatures increase, but likely won't have immediately observable impacts due to the long response times.

  3. The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

    KAUST Repository

    Cózar, Andrés

    2017-04-20

    The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively sampled for floating plastic debris from the Tara Oceans circumpolar expedition. Although plastic debris was scarce or absent in most of the Arctic waters, it reached high concentrations (hundreds of thousands of pieces per square kilometer) in the northernmost and easternmost areas of the Greenland and Barents seas. The fragmentation and typology of the plastic suggested an abundant presence of aged debris that originated from distant sources. This hypothesis was corroborated by the relatively high ratios of marine surface plastic to local pollution sources. Surface circulation models and field data showed that the poleward branch of the Thermohaline Circulation transfers floating debris from the North Atlantic to the Greenland and Barents seas, which would be a dead end for this plastic conveyor belt. Given the limited surface transport of the plastic that accumulated here and the mechanisms acting for the downward transport, the seafloor beneath this Arctic sector is hypothesized as an important sink of plastic debris.

  4. Using the Environmental Intelligence Framework to Address Arctic Issues: A Case Study of Alaskan Fisheries and Ocean Acidification

    Science.gov (United States)

    Mathis, J. T.; Osborne, E.; Bamzai, A. S.; Starkweather, S.

    2017-12-01

    Profound environmental change in the Arctic region is driving an urgent need for faster and more efficient knowledge creation and delivery for residents of the Arctic as well as stakeholders around the globe. The overarching issues at play include environmental stewardship, community health and cultural survival. To effectively address these issues, the Interagency Arctic Research Policy Committee (IAPRC) recently established the Environmental Intelligence Collaboration Team (EICT) that integrates observing capabilities, modelling efforts and data management. Since its inception, the EICT has been working to create pathways to environmental knowledge that sustains end-to-end integration of research across the linked steps of data integration, environmental observing, predictive modelling, assessing responsiveness to stakeholder needs and ultimately providing decision support. The EICT is currently focusing on the carbon-climate aspect of environmental knowledge and identifing specific decision-making needs to meet policy goals for topics such as carbon emissions from permafrost thaw, increasing wildfire frequency and ocean acidification. As a case study, we applied the Environmental Intelligence framework to understanding the effects of ocean acidification in southern Alaska where there are critical commercial and subsistence fisheries. The results of this work revealed that there is currently a 5-month window of optimal growing conditions at a hatchery facility for many juvenile shellfish although that window is expected to close by 2040. The outcome of this work relates directly to fisheries management decisions and identifies the need for continued Environmental Intelligence collection to monitor and mitigate ocean acidification in the Alaskan region.

  5. Inter-comparison of state-of-the-art MSS and geoid models in the Arctic Ocean

    DEFF Research Database (Denmark)

    Skourup, Henriette; Farrell, Sinead; Hendricks, Stefan

    in errors in the estimated freeboard heights, especially in areas with a sparse lead distribution in consolidated ice conditions. Additionally these errors can impact ocean geostrophic current estimates and remaining biases in the models may impact longer-term, multi-sensor oceanographic time-series of sea......State-of-the-art Arctic Ocean mean sea surface (MSS) and geoid models are used to support sea ice freeboard estimation from satellite altimeters, and for oceanographic studies. However, errors in a given model in the high frequency domain, e.g. due to unresolved gravity features, can result...

  6. Circumpolar measurements of speciated mercury, ozone and carbon monoxide in the boundary layer of the Arctic Ocean

    Science.gov (United States)

    Sommar, J.; Andersson, M. E.; Jacobi, H.-W.

    2010-06-01

    Using the Swedish icebreaker Oden as a platform, continuous measurements of airborne mercury (gaseous elemental mercury (Hg0), divalent gaseous mercury species HgIIX2(g) (acronym RGM) and mercury attached to particles (PHg)) and some long-lived trace gases (carbon monoxide CO and ozone O3) were performed over the North Atlantic and the Arctic Ocean. The measurements were performed for nearly three months (July-September 2005) during the Beringia 2005 expedition (from Göteborg, Sweden via the proper Northwest Passage to the Beringia region Alaska - Chukchi Penninsula - Wrangel Island and in-turn via a north-polar transect to Longyearbyen, Spitsbergen). The Beringia 2005 expedition was the first time that these species have been measured during summer over the Arctic Ocean going from 60° to 90° N. During the North Atlantic transect, concentration levels of Hg0, CO and O3 were measured comparable to typical levels for the ambient mid-hemispheric average. However, a rapid increase of Hg0 in air and surface water was observed when entering the ice-covered waters of the Canadian Arctic archipelago. Large parts of the measured waters were supersaturated with respect to Hg0, reflecting a strong disequilibrium. Heading through the sea ice of the Arctic Ocean, a fraction of the strong Hg0 pulse in the water was transferred with some time-delay into the air samples collected ~20 m above sea level. Several episodes of elevated Hg0 in air were encountered along the sea ice route with higher mean concentration (1.81±0.43 ng m-3) compared to the marine boundary layer over ice-free Arctic oceanic waters (1.55±0.21 ng m-3). In addition, the bulk of the variance in the temporal series of Hg0 concentrations was observed during July. The Oden Hg0 observations compare in this aspect very favourably with those at the coastal station Alert. Atmospheric boundary layer O3 mixing ratios decreased when initially sailing northward. In the Arctic, an O3 minimum around 15-20 ppbV was

  7. The Influence of Volcanic and Solar forcings on the Freshwater Budget of the Arctic Ocean

    Science.gov (United States)

    Davies, F. J.; Goosse, H.; Renssen, H.

    2012-04-01

    In recent decades the quantity and spatial extent of measurements for the atmospheric, terrestrial and oceanic sources and sinks, that comprise the freshwater budget of the Arctic Ocean has increased. This has been driven by a need to understand the variability of the freshwater budget, as a response to anthropogenically induced climate change, and the effects upon climate. However, the natural variability of the system due to specific forcings over a number of temporal scales, is yet to be clearly defined. This is due to several factors. A lack of a reliable freshwater proxy, coupled with a truncated instrumental record, make it difficult to elicit meaningful trends from the data that is currently available. In addition, modelling studies have not taken up the opportunity to evaluate the historical freshwater budget, instead focusing all their efforts in ascertaining the future response of the system. Therefore, when it comes to understanding the role individual forcings, such as volcanic and solar, have upon the natural variability of the freshwater budget, a noticeable void is evident. In order to understand the natural variations over the recent past one has to first consider the effects that natural forcings have upon the system, both independently and simultaneously. Therefore, in this study we seek to understand the effects solar and volcanic forcings have upon the freshwater budget of the Arctic, and by association, the climate. Here we present results of a series of transient simulations spanning the last 2000 years, performed with the earth model of intermediate complexity, LOVECLIM (Goosse et al., 2010). These series of simulations use a combination of orbital parameters, greenhouse gas concentrations, total solar irradiance and volcanic forcings. By comparing the simulation with only long-term forcings (orbital and greenhouse gas), to experiments in which the impacts of short-term forcings (solar and volcanic) are added incrementally to the effect of

  8. Energy landscapes shape microbial communities in hydrothermal systems on the Arctic Mid-Ocean Ridge.

    Science.gov (United States)

    Dahle, Håkon; Økland, Ingeborg; Thorseth, Ingunn H; Pederesen, Rolf B; Steen, Ida H

    2015-07-01

    Methods developed in geochemical modelling combined with recent advances in molecular microbial ecology provide new opportunities to explore how microbial communities are shaped by their chemical surroundings. Here, we present a framework for analyses of how chemical energy availability shape chemotrophic microbial communities in hydrothermal systems through an investigation of two geochemically different basalt-hosted hydrothermal systems on the Arctic Mid-Ocean Ridge: the Soria Moria Vent field (SMVF) and the Loki's Castle Vent Field (LCVF). Chemical energy landscapes were evaluated through modelling of the Gibbs energy from selected redox reactions under different mixing ratios between seawater and hydrothermal fluids. Our models indicate that the sediment-influenced LCVF has a much higher potential for both anaerobic and aerobic methane oxidation, as well as aerobic ammonium and hydrogen oxidation, than the SMVF. The modelled energy landscapes were used to develop microbial community composition models, which were compared with community compositions in environmental samples inside or on the exterior of hydrothermal chimneys, as assessed by pyrosequencing of partial 16S rRNA genes. We show that modelled microbial communities based solely on thermodynamic considerations can have a high predictive power and provide a framework for analyses of the link between energy availability and microbial community composition.

  9. Optimizing Ship Classification in the Arctic Ocean: A Case Study of Multi-Disciplinary Problem Solving

    Directory of Open Access Journals (Sweden)

    Mark Rahmes

    2014-08-01

    Full Text Available We describe a multi-disciplinary system model for determining decision making strategies based upon the ability to perform data mining and pattern discovery utilizing open source actionable information to prepare for specific events or situations from multiple information sources. We focus on combining detection theory with game theory for classifying ships in Arctic Ocean to verify ship reporting. More specifically, detection theory is used to determine probability of deciding if a ship or certain ship class is present or not. We use game theory to fuse information for optimal decision making on ship classification. Hierarchy game theory framework enables complex modeling of data in probabilistic modeling. However, applicability to big data is complicated by the difficulties of inference in complex probabilistic models, and by computational constraints. We provide a framework for fusing sensor inputs to help compare if the information of a ship matches its AIS reporting requirements using mixed probabilities from game theory. Our method can be further applied to optimizing other choke point scenarios where a decision is needed for classification of ground assets or signals. We model impact on decision making on accuracy by adding more parameters or sensors to the decision making process as sensitivity analysis.

  10. Micro-halocline enabled nutrient recycling may explain extreme Azolla event in the Eocene Arctic Ocean.

    Directory of Open Access Journals (Sweden)

    Monique M L van Kempen

    Full Text Available In order to understand the physicochemical mechanisms that could explain the massive growth of Azolla arctica in the Eocene Arctic Ocean, we carried out a laboratory experiment in which we studied the interacting effects of rain and wind on the development of salinity stratification, both in the presence and in the absence of a dense Azolla cover. Additionally, we carried out a mesocosm experiment to get a better understanding of the nutrient cycling within and beneath a dense Azolla cover in both freshwater and brackish water environments. Here we show that Azolla is able to create a windproof, small-scale salinity gradient in brackish waters, which allows for efficient recycling of nutrients. We suggest that this mechanism ensures the maintenance of a large standing biomass in which additional input of nutrients ultimately result in a further expansion of an Azolla cover. As such, it may not only explain the extent of the Azolla event during the Eocene, but also the absence of intact vegetative Azolla remains and the relatively low burial efficiency of organic carbon during this interval.

  11. Micro-halocline enabled nutrient recycling may explain extreme Azolla event in the Eocene Arctic Ocean.

    Science.gov (United States)

    van Kempen, Monique M L; Smolders, Alfons J P; Lamers, Leon P M; Roelofs, Jan G M

    2012-01-01

    In order to understand the physicochemical mechanisms that could explain the massive growth of Azolla arctica in the Eocene Arctic Ocean, we carried out a laboratory experiment in which we studied the interacting effects of rain and wind on the development of salinity stratification, both in the presence and in the absence of a dense Azolla cover. Additionally, we carried out a mesocosm experiment to get a better understanding of the nutrient cycling within and beneath a dense Azolla cover in both freshwater and brackish water environments. Here we show that Azolla is able to create a windproof, small-scale salinity gradient in brackish waters, which allows for efficient recycling of nutrients. We suggest that this mechanism ensures the maintenance of a large standing biomass in which additional input of nutrients ultimately result in a further expansion of an Azolla cover. As such, it may not only explain the extent of the Azolla event during the Eocene, but also the absence of intact vegetative Azolla remains and the relatively low burial efficiency of organic carbon during this interval.

  12. Protists in the polar regions: comparing occurrence in the Arctic and Southern oceans using pyrosequencing

    Directory of Open Access Journals (Sweden)

    Christian Wolf

    2015-05-01

    Full Text Available In the ongoing discussion of the distribution of protists, whether they are globally distributed or endemic to one or both of the polar regions is the subject of heated debate. In this study, we compared next-generation sequencing data from the Arctic and the Southern oceans to reveal the extent of similarities and dissimilarities between the protist communities in the polar regions. We found a total overlap of operational taxonomic units (OTUs between the two regions of 11.2%. On closer inspection of different taxonomic groups, the overlap ranged between 5.5% (haptophytes and 14.5% (alveolates. Within the different groups, the proportion of OTUs occurring in both regions greatly differed between the polar regions. On the one hand, the overlap between these two regions is remarkable, given the geographical distance between them. On the other hand, one could expect a greater overlap of OTUs between these regions on account of the similar environmental conditions. The overlap suggests a connection between the polar regions for at least certain species or that the evolutionary divergence has been slow, relative to the timescales of isolation. The different proportions of common OTUs among the groups or regions may be a result of different life cycle strategies or environmental adaptations.

  13. Autumn atmospheric response to the 2007 low Arctic sea ice extent in coupled ocean-atmosphere hindcasts

    Energy Technology Data Exchange (ETDEWEB)

    Orsolini, Yvan J. [Norwegian Institute for Air Research (NILU), PO BOX 100, Kjeller (Norway); Senan, Retish; Benestad, Rasmus E.; Melsom, Arne [Norwegian Meteorological Institute (met. no), Oslo (Norway)

    2012-06-15

    The autumn and early winter atmospheric response to the record-low Arctic sea ice extent at the end of summer 2007 is examined in ensemble hindcasts with prescribed sea ice extent, made with the European Centre for Medium-Range Weather Forecasts state-of-the-art coupled ocean-atmosphere seasonal forecast model. Robust, warm anomalies over the Pacific and Siberian sectors of the Arctic, as high as 10 C at the surface, are found in October and November. A regime change occurs by December, characterized by weaker temperatures anomalies extending through the troposphere. Geopotential anomalies extend from the surface up to the stratosphere, associated to deeper Aleutian and Icelandic Lows. While the upper-level jet is weakened and shifted southward over the continents, it is intensified over both oceanic sectors, especially over the Pacific Ocean. On the American and Eurasian continents, intensified surface Highs are associated with anomalous advection of cold (warm) polar air on their eastern (western) sides, bringing cooler temperatures along the Pacific coast of Asia and Northeastern North America. Transient eddy activity is reduced over Eurasia, intensified over the entrance and exit regions of the Pacific and Atlantic storm tracks, in broad qualitative agreement with the upper-level wind anomalies. Potential predictability calculations indicate a strong influence of sea ice upon surface temperatures over the Arctic in autumn, but also along the Pacific coast of Asia in December. When the observed sea ice extent from 2007 is prescribed throughout the autumn, a higher correlation of surface temperatures with meteorological re-analyses is found at high latitudes from October until mid-November. This further emphasises the relevance of sea ice for seasonal forecasting in the Arctic region, in the autumn. (orig.)

  14. Benthic Oxygen Uptake in the Arctic Ocean Margins - A Case Study at the Deep-Sea Observatory HAUSGARTEN (Fram Strait.

    Directory of Open Access Journals (Sweden)

    Cecile Cathalot

    Full Text Available The past decades have seen remarkable changes in the Arctic, a hotspot for climate change. Nevertheless, impacts of such changes on the biogeochemical cycles and Arctic marine ecosystems are still largely unknown. During cruises to the deep-sea observatory HAUSGARTEN in July 2007 and 2008, we investigated the biogeochemical recycling of organic matter in Arctic margin sediments by performing shipboard measurements of oxygen profiles, bacterial activities and biogenic sediment compounds (pigment, protein, organic carbon, and phospholipid contents. Additional in situ oxygen profiles were performed at two sites. This study aims at characterizing benthic mineralization activity along local bathymetric and latitudinal transects. The spatial coverage of this study is unique since it focuses on the transition from shelf to Deep Ocean, and from close to the ice edge to more open waters. Biogeochemical recycling across the continental margin showed a classical bathymetric pattern with overall low fluxes except for the deepest station located in the Molloy Hole (5500 m, a seafloor depression acting as an organic matter depot center. A gradient in benthic mineralization rates arises along the latitudinal transect with clearly higher values at the southern stations (average diffusive oxygen uptake of 0.49 ± 0.18 mmol O2 m-2 d-1 compared to the northern sites (0.22 ± 0.09 mmol O2 m-2 d-1. The benthic mineralization activity at the HAUSGARTEN observatory thus increases southward and appears to reflect the amount of organic matter reaching the seafloor rather than its lability. Although organic matter content and potential bacterial activity clearly follow this gradient, sediment pigments and phospholipids exhibit no increase with latitude whereas satellite images of surface ocean chlorophyll a indicate local seasonal patterns of primary production. Our results suggest that predicted increases in primary production in the Arctic Ocean could induce a larger

  15. Dissolved methane in the Beaufort Sea and the Arctic Ocean, 1992-2009; sources and atmospheric flux

    Science.gov (United States)

    Lorenson, Thomas D.; Greinert, Jens; Coffin, Richard B.

    2016-01-01

    Methane concentration and isotopic composition was measured in ice-covered and ice-free waters of the Arctic Ocean during eleven surveys spanning the years of 1992-1995 and 2009. During ice-free periods, methane flux from the Beaufort shelf varies from 0.14 to 0.43 mg CH4 m-2 day-1. Maximum fluxes from localized areas of high methane concentration are up to 1.52 mg CH4 m-2 day-1. Seasonal buildup of methane under ice can produce short-term fluxes of methane from the Beaufort shelf that varies from 0.28 to 1.01 to mg CH4 m-2 day-1. Scaled-up estimates of minimum methane flux from the Beaufort Sea and pan-Arctic shelf for both ice-free and ice-covered periods range from 0.02 Tg CH4 yr-1 and 0.30 Tg CH4 yr-1 respectively to maximum fluxes of 0.18 Tg CH4 yr-1 and 2.2 Tg CH4 yr-1 respectively. A methane flux of 0.36 Tg CH4 yr-1from the deep Arctic Ocean was estimated using data from 1993-94. The flux can be as much as 2.35 Tg CH4 yr-1 estimated from maximum methane concentrations and wind speeds of 12 m/s, representing only 0.42% of the annual atmospheric methane budget of ~560 Tg CH4 yr-1. There were no significant changes in methane fluxes during the time period of this study. Microbial methane sources predominate with minor influxes from thermogenic methane offshore Prudhoe Bay and the Mackenzie River delta and may include methane from gas hydrate. Methane oxidation is locally important on the shelf and is a methane sink in the deep Arctic Ocean.

  16. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing.

    Science.gov (United States)

    Marshall, John; Armour, Kyle C; Scott, Jeffery R; Kostov, Yavor; Hausmann, Ute; Ferreira, David; Shepherd, Theodore G; Bitz, Cecilia M

    2014-07-13

    In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around 'climate response functions' (CRFs), i.e. the response of the climate to 'step' changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate.

  17. The Experience of Using Autonomous Drifters for Studying the Ice Fields and the Ocean Upper Layer in the Arctic

    Directory of Open Access Journals (Sweden)

    S.V. Motyzhev

    2017-04-01

    Full Text Available The constructional and operational features of the BTC60/GPS/ice temperature-profiling drifters, developed in Marine Hydrophysical institute RAS for investigation of polar areas, are considered in this article. The drifters operated in completely automatic mode measuring air pressure, water temperatures at 17 depths down to 60 m, ocean pressures at 20, 40 and 60 m nominal depths and current locations. Accuracies of measurements were: +/-2 hPa for air pressure, +/-0.1°C for temperatures, +/-30 hPa for ocean pressure, 60 m for locations. Iridium satellite communication system was used for data transfer. Time delay between sample and delivery to a user did not exceed 10 minutes. More than 30 thermodrifters were developed in the Beaufort Sea – Canada Basin and central Arctic for the period from September 2012 to September 2014. Total duration of drifting buoys in operation was more of 4800 days. It was accepted the data of hourly samples about variability of ice-flows and ice field as a whole movements, thermo processes within upper water layer below ice, air pressure in near surface atmosphere of the Arctic region. The article includes some results of statistical analysis of data from drifter ID247950, the 3-year trajectory of which depended on the processes of transfer and evolution of ice fields in the Beaufort Sea – Canada Basin. Over a long period of time the Arctic buoy in-situ experiments allowed resulting about capability and reasonability to create reliable, technological and low-cost buoy network on basis of BTC60/GPS/ice drifters to monitor Arctic area of the World Ocean.

  18. Ocean Acidification in the Surface Waters of the Pacific-Arctic Boundary Regions

    Science.gov (United States)

    Mathis, J. T.; Cross, J. N.; Evans, W.; Doney, S. C.

    2016-02-01

    The continental shelves of the Pacific-Arctic Region (PAR) are especially vulnerable to the effects of ocean acidification (OA) because the intrusion of anthropogenic CO2 is not the only process that can reduce pH and carbonate mineral saturation states for aragonite (ΩArag). Enhanced sea-ice melt, respiration of organic matter, upwelling and riverine inputs have been shown to exacerbate CO2-driven ocean acidification in high-latitude regions. Additionally, the indirect effect of changing sea-ice coverage is providing a positive feedback to OA as more open water will allow for greater uptake of atmospheric CO2. Here, we compare model-based outputs from the Community Earth System Model with a subset of recent ship-based observations, and take an initial look at future model projections of surface water ΩArag in the Bering, Chukchi and Beaufort Seas. We then use the model outputs to define benchmark years when biological impacts are likely to result from reduced ΩArag. Each of the three continental shelf seas in the PAR will become undersaturated with respect to aragonite at approximately 30-year intervals, indicating that aragonite undersaturations gradually progress upstream along the flow path of the waters as they move north from the Pacific Ocean. However, naturally high variability in ΩArag may indicate higher resilience of the Bering Sea ecosystem to these low-ΩArag conditions than the Chukchi and the Beaufort Seas. Based on our initial results, we have determined that the annual mean for ΩArag will pass below the current range of natural variability in 2025 for the Beaufort Sea and 2027 for the Chukchi Sea. Because of the higher range of natural variability, the annual mean for ΩArag for the Bering Sea does not pass out of the natural variability range until 2044. As ΩArag in these shelf seas slips below the present-day range of large seasonal variability by midcentury, it could put tremendous pressure on the diverse ecosystems that support some of

  19. Reconstructing Methane Emission Events in the Arctic Ocean: Observations from the Past to Present

    Science.gov (United States)

    Panieri, G.; Mienert, J.; Fornari, D. J.; Torres, M. E.; Lepland, A.

    2015-12-01

    Methane hydrates are ice-like crystals that are present along continental margins, occurring in the pore space of deep sediments or as massive blocks near the seafloor. They form in high pressure and low temperature environments constrained by thermodynamic stability, and supply of methane. In the Arctic, gas hydrates are abundant, and the methane released by their destabilization can affect local to global carbon budgets and cycles, ocean acidification, and benthic community survival. With the aim to locate in space and time the periodicity of methane venting, CAGE is engaged in a vast research program in the Arctic, a component of which comprises the analyses of numerous sediment cores and correlative geophysical and geochemical data from different areas. Here we present results from combined analyses of biogenic carbonate archives along the western Svalbard Margin, which reveal past methane venting events in this region. The reconstruction of paleo-methane discharge is complicated by precipitation of secondary carbonate on foraminifera shells, driven by an increase in alkalinity during anaerobic oxidation of methane (AOM). The biogeochemical processes involved in methane cycling and processes that drive methane migration affect the depth where AOM occurs, with relevance to secondary carbonate formation. Our results show the value and complexity of separating primary vs. secondary signals in bioarchives with relevance to understanding fluid-burial history in methane seep provinces. Results from our core analyses are integrated with observations made during the CAGE15-2 cruise in May 2015, when we deployed a towed vehicle equipped with camera, multicore and water sampling capabilities. The instrument design was based on the Woods Hole Oceanographic Institution (WHOI) MISO TowCam sled equipped with a deep-sea digital camera and CTD real-time system. Sediment sampling was visually-guided using this system. In one of the pockmarks along the Vestnesa Ridge where high

  20. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from POLARSTERN in the Arctic Ocean, North Atlantic Ocean and others from 2007-12-03 to 2008-08-05 (NCEI Accession 0157407)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157407 includes Surface underway, chemical, meteorological and physical data collected from POLARSTERN in the Arctic Ocean, North Atlantic Ocean,...

  1. No maternal or direct effects of ocean acidification on egg hatching in the Arctic copepod Calanus glacialis.

    Science.gov (United States)

    Thor, Peter; Vermandele, Fanny; Carignan, Marie-Helene; Jacque, Sarah; Calosi, Piero

    2018-01-01

    Widespread ocean acidification (OA) is transforming the chemistry of the global ocean and the Arctic is recognised as the region where this transformation will occur at the fastest rate. Moreover, many Arctic species are considered less capable of tolerating OA due to their lower capacity for acid-base regulation. This inability may put severe restraints on many fundamental functions, such as growth and reproductive investments, which ultimately may result in reduced fitness. However, maternal effects may alleviate severe effects on the offspring rendering them more tolerant to OA. In a highly replicated experiment we studied maternal and direct effects of OA predicted for the Arctic shelf seas on egg hatching time and success in the keystone copepod species Calanus glacialis. We incubated females at present day conditions (pHT 8.0) and year 2100 extreme conditions (pHT 7.5) during oogenesis and subsequently reciprocally transplanted laid eggs between these two conditions. Statistical tests showed no effects of maternal or direct exposure to OA at this level. We hypothesise that C. glacialis may be physiologically adapted to egg production at low pH since oogenesis can also take place at conditions of potentially low haemolymph pH of the mother during hibernation in the deep.

  2. An Ocean Basin of Dirt? Using Molecular Biomarkers and Radiocarbon to Identify Organic Carbon Sources and their Preservation in the Arctic Ocean

    Science.gov (United States)

    Harvey, H.; Belicka, L. L.

    2005-12-01

    In the modern Arctic Ocean, primary production in waters over the broad continental shelves and under ice contributes an estimated 250 Mt/yr of POC to Arctic waters. The delivery of terrestrial material from large rivers, ice transport and through coastal erosion adds at least an additional 12 Mt/yr of POC. Although the marine organic carbon signal in Arctic Ocean exceeds that of terrestrial carbon by an order or magnitude or more, recent evidence suggests that this balance is not maintained and significant fractions of terrestrial carbon is preserved in sediments. Using an integrated approach combining lipid biomarkers and radiocarbon dating in particles and sediments, the process of organic carbon recycling and historical changes in its sources and preservation has been examined. A suite of lipid biomarkers in particles and sediments of western Arctic shelves and basins were measured and principle components analysis (PCA) used to allow a robust comparison among the 120+ individual compounds to assign organic sources and relative inputs. Offshore particles from the chlorophyll maximum contained abundant algal markers (e.g. 20:5 and 22:6 FAMEs), low concentrations of terrestrial markers (amyrins and 24-ethylcholest-5-en-3b-ol), and reflected modern 14C values. Particles present in deeper halocline waters also reflect marine production, but a portion of older, terrestrial carbon accompanies the sinking of the spring bloom. Surface and deeper sediments of basins contain older organic carbon and low concentrations of algal biomarkers, suggesting that marine carbon produced in surface waters is rapidly recycled. Taken together, these observations suggest that marine derived organic matter produced in shallow waters fuels carbon cycling, but relatively small amounts are preserved in sediments. As a result, the organic carbon preserved in sediments contrasts sharply to that typically observed in lower latitudes, with an increasing terrestrial signature with distance

  3. Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic

    Directory of Open Access Journals (Sweden)

    H. Hayashida

    2017-06-01

    Full Text Available Sea ice represents an additional oceanic source of the climatically active gas dimethyl sulfide (DMS for the Arctic atmosphere. To what extent this source contributes to the dynamics of summertime Arctic clouds is, however, not known due to scarcity of field measurements. In this study, we developed a coupled sea ice–ocean ecosystem–sulfur cycle model to investigate the potential impact of bottom-ice DMS and its precursor dimethylsulfoniopropionate (DMSP on the oceanic production and emissions of DMS in the Arctic. The results of the 1-D model simulation were compared with field data collected during May and June of 2010 in Resolute Passage. Our results reproduced the accumulation of DMS and DMSP in the bottom ice during the development of an ice algal bloom. The release of these sulfur species took place predominantly during the earlier phase of the melt period, resulting in an increase of DMS and DMSP in the underlying water column prior to the onset of an under-ice phytoplankton bloom. Production and removal rates of processes considered in the model are analyzed to identify the processes dominating the budgets of DMS and DMSP both in the bottom ice and the underlying water column. When openings in the ice were taken into account, the simulated sea–air DMS flux during the melt period was dominated by episodic spikes of up to 8.1 µmol m−2 d−1. Further model simulations were conducted to assess the effects of the incorporation of sea-ice biogeochemistry on DMS production and emissions, as well as the sensitivity of our results to changes of uncertain model parameters of the sea-ice sulfur cycle. The results highlight the importance of taking into account both the sea-ice sulfur cycle and ecosystem in the flux estimates of oceanic DMS near the ice margins and identify key uncertainties in processes and rates that should be better constrained by new observations.

  4. Underway pCO2 Measurements in Surface Waters and the Atmosphere During the R/V Xue Long Arctic CHINARE2010 Expedition in the North Pacific Ocean, Bering Sea and Arctic Ocean from 2010-07-09 to 2010-09-06 (NCEI Accession 0164193)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0164193 includes Surface underway, chemical, meteorological and physical data collected from R/V Xue Long Arctic CHINARE2010 Expedition in the North...

  5. Plastic ingestion by juvenile polar cod (Boreogadus saida) in the Arctic Ocean

    NARCIS (Netherlands)

    Kühn, Susanne; Schaafsma, Fokje L.; Werven, van Bernike; Flores, Hauke; Bergmann, Melanie; Egelkraut-Holtus, Marion; Tekman, Mine B.; Franeker, van Jan A.

    2018-01-01

    One of the recently recognised stressors in Arctic ecosystems concerns plastic litter. In this study, juvenile polar cod (Boreogadus saida) were investigated for the presence of plastics in their stomachs. Polar cod is considered a key species in the Arctic ecosystem. The fish were collected both

  6. Sensitivity to ocean acidification parallels natural pCO2 gradients experienced by Arctic copepods under winter sea ice

    Science.gov (United States)

    Lewis, Ceri N.; Brown, Kristina A.; Edwards, Laura A.; Cooper, Glenn; Findlay, Helen S.

    2013-01-01

    The Arctic Ocean already experiences areas of low pH and high CO2, and it is expected to be most rapidly affected by future ocean acidification (OA). Copepods comprise the dominant Arctic zooplankton; hence, their responses to OA have important implications for Arctic ecosystems, yet there is little data on their current under-ice winter ecology on which to base future monitoring or make predictions about climate-induced change. Here, we report results from Arctic under-ice investigations of copepod natural distributions associated with late-winter carbonate chemistry environmental data and their response to manipulated pCO2 conditions (OA exposures). Our data reveal that species and life stage sensitivities to manipulated OA conditions were correlated with their vertical migration behavior and with their natural exposures to different pCO2 ranges. Vertically migrating adult Calanus spp. crossed a pCO2 range of >140 μatm daily and showed only minor responses to manipulated high CO2. Oithona similis, which remained in the surface waters and experienced a pCO2 range of <75 μatm, showed significantly reduced adult and nauplii survival in high CO2 experiments. These results support the relatively untested hypothesis that the natural range of pCO2 experienced by an organism determines its sensitivity to future OA and highlight that the globally important copepod species, Oithona spp., may be more sensitive to future high pCO2 conditions compared with the more widely studied larger copepods. PMID:24297880

  7. The delivery of mercury to the Beaufort Sea of the Arctic Ocean by the Mackenzie River.

    Science.gov (United States)

    Leitch, Daniel R; Carrie, Jesse; Lean, David; Macdonald, Robie W; Stern, Gary A; Wang, Feiyue

    2007-02-01

    Very high levels of mercury (Hg) have recently been reported in marine mammals and other higher trophic-level biota in the Mackenzie Delta and Beaufort Sea of the western Arctic Ocean. To quantify the input of Hg (particulate, dissolved and methylated) by the Mackenzie River as a potential source for Hg in the ecosystem, surface water and sediment samples were taken from 79 sites in the lower Mackenzie Basin during three consecutive summers (2003-2005) and analyzed for Hg and methylmercury (MeHg). Intensive studies were also carried out in the Mackenzie Delta during the freshets of 2004 and 2005. Large seasonal and annual variations were found in Hg concentrations in the river, coincident with the variations in water discharge. Increased discharges during spring freshet and during the summers of 2003 and 2005 compared to 2004 were mirrored by higher Hg concentrations. The correlation between Hg concentration and riverflow suggests additional Hg sources during periods of high water, potentially from increased surface inundation and increased bank erosion. The increase in the Hg concentration with increasing water discharge amplifies the annual Hg and MeHg fluxes during high water level years. For the period 2003-2005, the Hg and MeHg fluxes from the Mackenzie River to the Beaufort Sea averaged 2.2 tonnes/yr and 15 kg/yr, respectively, the largest known Hg source to the Beaufort Sea. More than half of the mercury flux occurs during the short spring freshet season which coincides with the period of rapid growth of marine biota. Consequently, the Mackenzie River input potentially provides the major mercury source to marine mammals of the Beaufort Sea. The Hg and MeHg fluxes from the Mackenzie River are expected to further increase with the projected climate warming in the Mackenzie Basin.

  8. 20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean.

    Science.gov (United States)

    Jantunen, Liisa M; Wong, Fiona; Gawor, Anya; Kylin, Henrik; Helm, Paul A; Stern, Gary A; Strachan, William M J; Burniston, Deborah A; Bidleman, Terry F

    2015-12-01

    The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water-air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR exchange direction of other CUPs varied. Understanding the processes and current state of air-surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

  9. Modeling the winter-to-summer transition of prokaryotic and viral abundance in the Arctic Ocean.

    Science.gov (United States)

    Winter, Christian; Payet, Jérôme P; Suttle, Curtis A

    2012-01-01

    One of the challenges in oceanography is to understand the influence of environmental factors on the abundances of prokaryotes and viruses. Generally, conventional statistical methods resolve trends well, but more complex relationships are difficult to explore. In such cases, Artificial Neural Networks (ANNs) offer an alternative way for data analysis. Here, we developed ANN-based models of prokaryotic and viral abundances in the Arctic Ocean. The models were used to identify the best predictors for prokaryotic and viral abundances including cytometrically-distinguishable populations of prokaryotes (high and low nucleic acid cells) and viruses (high- and low-fluorescent viruses) among salinity, temperature, depth, day length, and the concentration of Chlorophyll-a. The best performing ANNs to model the abundances of high and low nucleic acid cells used temperature and Chl-a as input parameters, while the abundances of high- and low-fluorescent viruses used depth, Chl-a, and day length as input parameters. Decreasing viral abundance with increasing depth and decreasing system productivity was captured well by the ANNs. Despite identifying the same predictors for the two populations of prokaryotes and viruses, respectively, the structure of the best performing ANNs differed between high and low nucleic acid cells and between high- and low-fluorescent viruses. Also, the two prokaryotic and viral groups responded differently to changes in the predictor parameters; hence, the cytometric distinction between these populations is ecologically relevant. The models imply that temperature is the main factor explaining most of the variation in the abundances of high nucleic acid cells and total prokaryotes and that the mechanisms governing the reaction to changes in the environment are distinctly different among the prokaryotic and viral populations.

  10. Modeling the Winter–to–Summer Transition of Prokaryotic and Viral Abundance in the Arctic Ocean

    Science.gov (United States)

    Winter, Christian; Payet, Jérôme P.; Suttle, Curtis A.

    2012-01-01

    One of the challenges in oceanography is to understand the influence of environmental factors on the abundances of prokaryotes and viruses. Generally, conventional statistical methods resolve trends well, but more complex relationships are difficult to explore. In such cases, Artificial Neural Networks (ANNs) offer an alternative way for data analysis. Here, we developed ANN-based models of prokaryotic and viral abundances in the Arctic Ocean. The models were used to identify the best predictors for prokaryotic and viral abundances including cytometrically-distinguishable populations of prokaryotes (high and low nucleic acid cells) and viruses (high- and low-fluorescent viruses) among salinity, temperature, depth, day length, and the concentration of Chlorophyll-a. The best performing ANNs to model the abundances of high and low nucleic acid cells used temperature and Chl-a as input parameters, while the abundances of high- and low-fluorescent viruses used depth, Chl-a, and day length as input parameters. Decreasing viral abundance with increasing depth and decreasing system productivity was captured well by the ANNs. Despite identifying the same predictors for the two populations of prokaryotes and viruses, respectively, the structure of the best performing ANNs differed between high and low nucleic acid cells and between high- and low-fluorescent viruses. Also, the two prokaryotic and viral groups responded differently to changes in the predictor parameters; hence, the cytometric distinction between these populations is ecologically relevant. The models imply that temperature is the main factor explaining most of the variation in the abundances of high nucleic acid cells and total prokaryotes and that the mechanisms governing the reaction to changes in the environment are distinctly different among the prokaryotic and viral populations. PMID:23285186

  11. Distributions of nutrients, dissolved organic carbon and carbohydrates in the western Arctic Ocean

    Science.gov (United States)

    Wang, Deli; Henrichs, Susan M.; Guo, Laodong

    2006-09-01

    Seawater samples were collected from stations along a transect across the shelf-basin interface in the western Arctic Ocean during September 2002, and analyzed for nutrients, dissolved organic carbon (DOC), and total dissolved carbohydrate (TDCHO) constituents, including monosaccharides (MCHO) and polysaccharides (PCHO). Nutrients (nitrate, ammonium, phosphate and dissolved silica) were depleted at the surface, especially nitrate. Their concentrations increased with increasing depth, with maxima centered at ˜125 m depth within the halocline layer, then decreased with increasing depth below the maxima. Both ammonium and phosphate concentrations were elevated in shelf bottom waters, indicating a possible nutrient source from sediments, and in a plume that extended into the upper halocline waters offshore. Concentrations of DOC ranged from 45 to 85 μM and had an inverse correlation with salinity, indicating that mixing is a control on DOC concentrations. Concentrations of TDCHO ranged from 2.5 to 19 μM-C, comprising 13-20% of the bulk DOC. Higher DOC concentrations were found in the upper water column over the shelf along with higher TDCHO concentrations. Within the TDCHO pool, the concentrations of MCHO ranged from 0.4 to 8.6 μM-C, comprising 20-50% of TDCHO, while PCHO concentrations ranged from 0.5 to 13.6 μM-C, comprising 50-80% of the TDCHO. The MCHO/TDCHO ratio was low in the upper 25 m of the water column, followed by a high MCHO/TDCHO ratio between 25 and 100 m, and a low MCHO/TDCHO ratio again below 100 m. The high MCHO/TDCHO ratio within the halocline layer likely resulted from particle decomposition and associated release of MCHO, whereas the low MCHO/TDCHO (or high PCHO/TDCHO) ratio below the halocline layer could have resulted from slow decomposition and additional particulate CHO sources.

  12. Environmental Assessment for a Marine Geophysical Survey of Parts of the Arctic Ocean, August-September 2010

    Science.gov (United States)

    Haley, Beth; Ireland, Darren; Childs, Jonathan R.

    2010-01-01

    According to the United Nations Convention on the Law of the Sea (UNCLOS), individual nations? sovereign rights extend to 200 nautical miles (n.mi.) (370 km) offshore or to a maritime boundary in an area called the continental shelf. These rights include jurisdiction over all resources in the water column and on and beneath the seabed. Article 76 of UNCLOS also establishes the criteria to determine areas beyond the 200 n.mi. (370 km) limit that could be defined as ?extended continental shelf,? where a nation could extend its sovereign rights over the seafloor and sub-seafloor (As used in UNCLOS, ?continental shelf? refers to a legally defined region of the sea floor rather than a morphological shallow-water area adjacent to continents commonly used by geologists and hydrographers.). This jurisdiction provided in Article 76 includes resources on and below the seafloor but not in the water column. The United States has been acquiring data to determine the outer limits of its extended continental shelf in the Arctic and has a vested interest in declaring and receiving international recognition of the reach of its extended continental shelf. The U.S. collaborated with Canada in 2008 and 2009 on extended continental shelf studies in the Arctic Ocean. The U.S. Coast Guard (USCG) Cutter Healy worked with the Canadian Coast Guard ship Louis S. St. Laurent to map the continental shelf beyond 200 n.mi. (370 km) in the Arctic. Each icebreaking vessel contributed different capabilities in order to collect data needed by both nations more efficiently in order to save money, avoid redundancy, and foster cooperation. Generally, the Healy collects bathymetric (sea-floor topography) data and the Louis S. St. Laurent collects seismic reflection profile data. The vessels work in concert when ice conditions are heavy, with one vessel breaking ice for the ship collecting data. The Canadian Environmental Assessments for these projects are available on line at http://www.ceaa.gc.ca/052

  13. Simulating the natural variability of the freshwater budget of the Arctic ocean from the mid to late Holocene using LOVECLIM

    Science.gov (United States)

    Davies, F. J.; Goosse, H.; Renssen, H.

    2012-04-01

    The influence of freshwater on the long term climatic variability of the Arctic region is currently of significant interest. Alterations to the natural variability of the oceanic, terrestrial and atmospheric sources of freshwater to the Arctic ocean, caused by anthropogenic induced warming, are likely to have far reaching effects on oceanic processes and climate. A number of these changes are already observable, such as an intensification of the hydrological cycle, a 7% increase in Eurasian river runoff (1936-1999), a 9% reduction of sea-ice extent per decade (1979-2006), a 120km northward migration of permafrost in Northern Canada (1968-1994), and air temperatures 6°C warmer, in parts, from 2007 to 2010, when compared to the 1958-1996 average. All of these changes add another layer of complexity to understanding the role of the freshwater budget, and this makes it difficult to say with any certainty how these future changes will impact freshwater fluxes of the Arctic gateways, such as the Bering Strait, Fram Strait, Canadian Arctic Archipelago and the Barents Sea inflow. Despite these difficulties, there have been studies that have integrated the available data, from both in situ measurements and modelling studies, and used this as a basis to form a picture of the current freshwater budget, and then project upon these hypotheses for the future (Holland et al., 2007). However, one particular aspect of these future projections that is lacking is the accountability of how much future variance is attributable to both natural variability and anthropogenic influences. Here we present results of a mid to late (6-0ka) Holocene transient simulation, using the earth model of intermediate complexity, LOVECLIM (Goosse et al., 2010). The model is forced with orbital and greenhouse gas forcings appropriate for the time period. The results will highlight the natural variability of the oceanic, terrestrial and atmospheric components of the freshwater budget, over decadal and

  14. Temperature, salinity, and nutrients data from CTD and bottle casts in the Arctic, North Atlantic, North Pacific Oceans from the TELEOST and other platforms from 01 August 1960 to 22 April 2000 (NODC Accession 0000496)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD, bottle, and other data were collected in the Arctic, North Atlantic, and Pacific Oceans from the TELEOST and other platforms from 01 August 1960 to 22 April...

  15. Temperature, salinity, and nutrients data from bottle, CTD, MBT, and XBT casts in the Arctic Ocean and other locations from the PARIZEAU and other platforms from 01 August 1924 to 15 November 1997 (NODC Accession 0000518)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bottle, CTD, MBT, and XBT data were collected from the PARIZEAU and other platforms in the Arctic Ocean and other locations from 01 August 1924 to 15 November 1997....

  16. Temperature, salinity, and nutrients data from CTD, MBT, and bottle casts in the Arctic, North Atlantic and North Pacific Oceans from the SACKVILLE and other platforms from 1928-05-12 to 1998-11-03 (NODC Accession 0000448)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD, MBT, bottle and other data were collected in the Arctic, North Atlantic, and North Pacific Oceans from the SACKVILLE and other platforms from 12 May 1928 to 03...

  17. Temperature, salinity, and nutrients data from bottle, CTD, and XBT casts in the Arctic, North Atlantic, and North Pacific Oceans from the ANTON DOHRN and other platforms from 02 July 1916 to 28 January 1999 (NODC Accession 0000677)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bottle, CTD, and XBT data were collected in the Arctic, North Atlantic, and North Pacific Oceans from the ANTON DOHRN and other vessels from 02 July 1916 to 28...

  18. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HEALY in the Arctic Ocean and Beaufort Sea from 2003-09-11 to 2003-10-18 (NODC Accession 0115676)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0115676 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean and Beaufort Sea...

  19. Individual animals and other data collected using visual observations and other instruments from AIRCRAFT in the Arctic Ocean from 02 August 1979 to 18 October 1982 (NODC Accession 8400149)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Individual animals and other data were collected using visual observations and other instruments in the Arctic Ocean by AIRCRAFT. Data were collected from 02 August...

  20. Temperature, salinity, and nutrients profiles from bottle, CTD, MBT, and XBT casts in the Arctic Ocean and other locations from the WALTHER HERWIG and other platforms from 12 May 1928 to 04 December 1999 (NODC Accession 0000517)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bottle, CTD, MBT, and XBT data were collected from the WALTHER HERWIG in the Arctic Ocean and other locations from 12 May 1928 to 04 December 1999. Data include...

  1. Plankton and nutrients data collected using net and CTD casts in the Arctic Ocean from the OSHORO MARU and HOKUSEI MARU from 11 June 1984 to 03 September 1994 (NODC Accession 0000855)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Plankton and nutrients data were collected using net and CTD casts from the OSHORO MARU and HOKUSEI MARU in the Arctic Ocean. Data were collected from 11 June 1984...

  2. Physical and chemical oceanographic profile data, and meteorological data collected in the Atlantic and Arctic Oceans, and adjoining seas by multiple platforms from 14 August 1951 to 27 October 1994 (NODC Accession 0073741)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, oxygen, silicate, phosphate, nitrite, nitrate, alkalinity, and pH data collected in Arctic Ocean, Barents Sea, East Siberian Sea, Greenland...

  3. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HEALY in the Arctic Ocean and Beaufort Sea from 2004-07-18 to 2004-08-26 (NODC Accession 0113548)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0113548 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean and Beaufort Sea...

  4. Chemical data from bottle casts in the Arctic Ocean and other Sea areas by the University of Alaska, from 16 April 1948 to 17 September 2000 (NODC Accession 0000918)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical data were collected using bottle casts from multiple vessels in the Arctic Ocean and other Sea areas from 16 April 1948 to 17 September 2000. Data were...

  5. Nutrients, transient tracers, and other variables collected from profile and discrete sampling observations using Niskin bottle, CTD and other instruments in the Arctic Ocean from 2005-05-02 to 2009-05-18 (NODC Accession 0117695)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0117695 includes discrete CTD profile data collected from aircraft lending expeditions in the Arctic Ocean from 2005-05-02 to 2009-05-18. All...

  6. Empirical ocean color algorithms and bio-optical properties of the western coastal waters of Svalbard, Arctic

    Science.gov (United States)

    Son, Young-Sun; Kim, Hyun-cheol

    2018-05-01

    Chlorophyll (Chl) concentration is one of the key indicators identifying changes in the Arctic marine ecosystem. However, current Chl algorithms are not accurate in the Arctic Ocean due to different bio-optical properties from those in the lower latitude oceans. In this study, we evaluated the current Chl algorithms and analyzed the cause of the error in the western coastal waters of Svalbard, which are known to be sensitive to climate change. The NASA standard algorithms showed to overestimate the Chl concentration in the region. This was due to the high non-algal particles (NAP) absorption and colored dissolved organic matter (CDOM) variability at the blue wavelength. In addition, at lower Chl concentrations (0.1-0.3 mg m-3), chlorophyll-specific absorption coefficients were ∼2.3 times higher than those of other Arctic oceans. This was another reason for the overestimation of Chl concentration. OC4 algorithm-based regionally tuned-Svalbard Chl (SC4) algorithm for retrieving more accurate Chl estimates reduced the mean absolute percentage difference (APD) error from 215% to 49%, the mean relative percentage difference (RPD) error from 212% to 16%, and the normalized root mean square (RMS) error from 211% to 68%. This region has abundant suspended matter due to the melting of tidal glaciers. We evaluated the performance of total suspended matter (TSM) algorithms. Previous published TSM algorithms generally overestimated the TSM concentration in this region. The Svalbard TSM-single band algorithm for low TSM range (ST-SB-L) decreased the APD and RPD errors by 52% and 14%, respectively, but the RMS error still remained high (105%).

  7. Arctic security in an age of climate change

    Energy Technology Data Exchange (ETDEWEB)

    Kraska, James (ed.)

    2013-03-01

    Publisher review: This book examines Arctic defense policy and military security from the perspective of all eight Arctic states. In light of climate change and melting ice in the Arctic Ocean, Canada, Russia, Denmark (Greenland), Norway and the United States, as well as Iceland, Sweden and Finland, are grappling with an emerging Arctic security paradigm. This volume brings together the world's most seasoned Arctic political-military experts from Europe and North America to analyze how Arctic nations are adapting their security postures to accommodate increased shipping, expanding naval presence, and energy and mineral development in the polar region. The book analyzes the ascent of Russia as the first 'Arctic superpower', the growing importance of polar security for NATO and the Nordic states, and the increasing role of Canada and the United States in the region.(Author)

  8. Seasonal Evolution and Interannual Variability of the Local Solar Energy Absorbed by the Arctic Sea Ice-Ocean System

    Science.gov (United States)

    Perovich, Donald K.; Nghiem, Son V.; Markus, Thorsten; Schwieger, Axel

    2007-01-01

    The melt season of the Arctic sea ice cover is greatly affected by the partitioning of the incident solar radiation between reflection to the atmosphere and absorption in the ice and ocean. This partitioning exhibits a strong seasonal cycle and significant interannual variability. Data in the period 1998, 2000-2004 were analyzed in this study. Observations made during the 1997-1998 SHEBA (Surface HEat Budget of the Arctic Ocean) field experiment showed a strong seasonal dependence of the partitioning, dominated by a five-phase albedo evolution. QuikSCAT scatterometer data from the SHEBA region in 1999-2004 were used to further investigate solar partitioning in summer. The time series of scatterometer data were used to determine the onset of melt and the beginning of freezeup. This information was combined with SSM/I-derived ice concentration, TOVS-based estimates of incident solar irradiance, and SHEBA results to estimate the amount of solar energy absorbed in the ice-ocean system for these years. The average total solar energy absorbed in the ice-ocean system from April through September was 900 MJ m(sup -2). There was considerable interannual variability, with a range of 826 to 1044 MJ m(sup -2). The total amount of solar energy absorbed by the ice and ocean was strongly related to the date of melt onset, but only weakly related to the total duration of the melt season or the onset of freezeup. The timing of melt onset is significant because the incident solar energy is large and a change at this time propagates through the entire melt season, affecting the albedo every day throughout melt and freezeup.

  9. An Assessment of State-of-the-Art Mean Sea Surface and Geoid Models of the Arctic Ocean: Implications for Sea Ice Freeboard Retrieval

    DEFF Research Database (Denmark)

    Skourup, Henriette; Farrell, Sinéad Louise; Hendricks, Stefan

    2017-01-01

    in a given model in the high frequency domain, primarily due to unresolved gravity features, can result in errors in the estimated along-track freeboard. These errors are exacerbated in areas with a sparse lead distribution in consolidated ice pack conditions. Additionally model errors can impact ocean......State-of-the-art Arctic Ocean mean sea surface (MSS) models and global geoid models (GGMs) are used to support sea ice freeboard estimation from satellite altimeters, as well as in oceanographic studies such as mapping sea level anomalies and mean dynamic ocean topography. However, errors...... geostrophic currents, derived from satellite altimeter data, while remaining biases in these models may impact longer-term, multi-sensor oceanographic time-series of sea level change in the Arctic. This study focuses on an assessment of five state-of-the-art Arctic MSS models (UCL13/04, DTU15...

  10. Can we constrain postglacial sedimentation in the western Arctic Ocean by ramped pyrolysis 14C? A case study from the Chukchi-Alaskan margin.

    Science.gov (United States)

    Suzuki, K.; Yamamoto, M.; Rosenheim, B. E.; Omori, T.; Polyak, L.; Nam, S. I.

    2017-12-01

    The Arctic Ocean underwent dramatic climate changes in the past. Variations in sea-ice extent and ocean current system in the Arctic cause changes in surface albedo and deep water formation, which have global climatic implications. However, Arctic paleoceanographic studies are lagging behind the other oceans due largely to chronostratigraphic difficulties. One of the reasons for this is a scant presence of material suitable for 14C dating in large areas of the Arctic seafloor. To enable improved age constraints for sediments impoverished in datable material, we apply ramped pyrolysis 14C method (Ramped PyrOx 14C, Rosenheim et al., 2008) to sedimentary records from the Chukchi-Alaska margin recovering Holocene to late-glacial deposits. Samples were divided into five fraction products by gradual heating sedimentary organic carbon from ambient laboratory temperature to 1000°C. The thermographs show a trimodal pattern of organic matter decomposition over temperature, and we consider that CO2 generated at the lowest temperature range was derived from autochthonous organic carbon contemporaneous with sediment deposition, similar to studies in the Antarctic margin and elsewhere. For verification of results, some of the samples treated for ramped pyrolysis 14C were taken from intervals dated earlier by AMS 14C using bivalve mollusks. Ultimately, our results allow a new appraisal of deglacial to Holocene deposition at the Chukchi-Alaska margin with potential to be applied to other regions of the Arctic Ocean.

  11. Utilizing chromophoric dissolved organic matter measurements to derive export and reactivity of dissolved organic carbon exported to the Arctic Ocean: A case study of the Yukon River, Alaska

    Science.gov (United States)

    Spencer, R.G.M.; Aiken, G.R.; Butler, K.D.; Dornblaser, M.M.; Striegl, Robert G.; Hernes, P.J.

    2009-01-01

    The quality and quantity of dissolved organic matter (DOM) exported by Arctic rivers is known to vary with hydrology and this exported material plays a fundamental role in the biogeochemical cycling of carbon at high latitudes. We highlight the potential of optical measurements to examine DOM quality across the hydrograph in Arctic rivers. Furthermore, we establish chromophoric DOM (CDOM) relationships to dissolved organic carbon (DOC) and lignin phenols in the Yukon River and model DOC and lignin loads from CDOM measurements, the former in excellent agreement with long-term DOC monitoring data. Intensive sampling across the historically under-sampled spring flush period highlights the importance of this time for total export of DOC and particularly lignin. Calculated riverine DOC loads to the Arctic Ocean show an increase from previous estimates, especially when new higher discharge data are incorporated. Increased DOC loads indicate decreased residence times for terrigenous DOM in the Arctic Ocean with important implications for the reactivity and export of this material to the Atlantic Ocean. Citation: Spencer, R. G. M., G. R. Aiken, K. D. Butler, M. M. Dornblaser, R. G. Striegl, and P. J. Hernes (2009), Utilizing chromophoric dissolved organic matter measurements to derive export and reactivity of dissolved organic carbon exported to the Arctic Ocean: A case study of the Yukon River, Alaska, Geophys. Res. Lett., 36, L06401, doi:10.1029/ 2008GL036831. Copyright 2009 by the American Geophysical Union.

  12. A synthesis of light absorption properties of the Arctic Ocean: application to semianalytical estimates of dissolved organic carbon concentrations from space

    Science.gov (United States)

    Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Bélanger, S.; Bricaud, A.

    2014-06-01

    In addition to scattering coefficients, the light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean (e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012), the data sets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database of the Arctic Ocean by pooling the majority of published data sets and merging new data sets. Our results show that the total nonwater absorption coefficients measured in the eastern Arctic Ocean (EAO; Siberian side) are significantly higher than in the western Arctic Ocean (WAO; North American side). This higher absorption is explained by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off North America. In contrast, the relationship between the phytoplankton absorption (aϕ(λ)) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semianalytical CDOM absorption algorithm is based on chl a-specific aϕ(λ) values (Matsuoka et al., 2013), this result indirectly suggests that CDOM absorption can be appropriately derived not only for the WAO but also for the EAO using ocean color data. Based on statistics, derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC versus CDOM relationships, a semianalytical algorithm for estimating DOC concentrations for river-influenced coastal waters of the Arctic Ocean is presented and applied to satellite

  13. Upper-Ocean Variability in the Arctic’s Amundsen and Nansen Basins

    Science.gov (United States)

    2017-05-01

    public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions...NUMBER 6. AUTHOR(S) Sd. PROJECT NUMBER Toole, John M. WHOI132547SP Krishfield, Richard A. Se. TASK NUMBER Cole, Sylvia T. Sf. WORK UNIT NUMBER...findings of the MIZ program to the European sector of the Arctic with its markedly different thermohaline stratification. 1S. SUBJECT TERMS Arctic

  14. Distribution and long-range transport of polyfluoroalkyl substances in the Arctic, Atlantic Ocean and Antarctic coast.

    Science.gov (United States)

    Zhao, Zhen; Xie, Zhiyong; Möller, Axel; Sturm, Renate; Tang, Jianhui; Zhang, Gan; Ebinghaus, Ralf

    2012-11-01

    The global distribution and long-range transport of polyfluoroalkyl substances (PFASs) were investigated using seawater samples collected from the Greenland Sea, East Atlantic Ocean and the Southern Ocean in 2009-2010. Elevated levels of ΣPFASs were detected in the North Atlantic Ocean with the concentrations ranging from 130 to 650 pg/L. In the Greenland Sea, the ΣPFASs concentrations ranged from 45 to 280 pg/L, and five most frequently detected compounds were perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS), perfluorohexanoic acid (PFHxA), perfluorooctane sulfonate (PFOS) and perfluorobutane sulfonate (PFBS). PFOA (15 pg/L) and PFOS (25-45 pg/L) were occasionally found in the Southern Ocean. In the Atlantic Ocean, the ΣPFASs concentration decreased from 2007 to 2010. The elevated PFOA level that resulted from melting snow and ice in Greenland Sea implies that the Arctic may have been driven by climate change and turned to be a source of PFASs for the marine ecosystem. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Projected Impact of Climate Change on the Energy Budget of the Arctic Ocean by a Global Climate Model

    Science.gov (United States)

    Miller, James R.; Russell, Gary L.; Hansen, James E. (Technical Monitor)

    2001-01-01

    The annual energy budget of the Arctic Ocean is characterized by a net heat loss at the air-sea interface that is balanced by oceanic heat transport into the Arctic. The energy loss at the air-sea interface is due to the combined effects of radiative, sensible, and latent heat fluxes. The inflow of heat by the ocean can be divided into two components: the transport of water masses of different temperatures between the Arctic and the Atlantic and Pacific Oceans and the export of sea ice, primarily through Fram Strait. Two 150-year simulations (1950-2099) of a global climate model are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. One is a control simulation for the present climate with constant 1950 atmospheric composition, and the other is a transient experiment with observed GHGs from 1950 to 1990 and 0.5% annual compounded increases of CO2 after 1990. For the present climate the model agrees well with observations of radiative fluxes at the top of the atmosphere, atmospheric advective energy transport into the Arctic, and surface air temperature. It also simulates the seasonal cycle and summer increase of cloud cover and the seasonal cycle of sea-ice cover. In addition, the changes in high-latitude surface air temperature and sea-ice cover in the GHG experiment are consistent with observed changes during the last 40 and 20 years, respectively. Relative to the control, the last 50-year period of the GHG experiment indicates that even though the net annual incident solar radiation at the surface decreases by 4.6 W(per square meters) (because of greater cloud cover and increased cloud optical depth), the absorbed solar radiation increases by 2.8 W(per square meters) (because of less sea ice). Increased cloud cover and warmer air also cause increased downward thermal radiation at the surface so that the net radiation into the ocean increases by 5.0 Wm-2. The annual increase in radiation into the ocean, however, is

  16. Investigations of a novel fauna from hydrothermal vents along the Arctic Mid-Ocean Ridge (AMOR) (Invited)

    Science.gov (United States)

    Rapp, H.; Schander, C.; Halanych, K. M.; Levin, L. A.; Sweetman, A.; Tverberg, J.; Hoem, S.; Steen, I.; Thorseth, I. H.; Pedersen, R.

    2010-12-01

    The Arctic deep ocean hosts a variety of habitats ranging from fairly uniform sedimentary abyssal plains to highly variable hard bottoms on mid ocean ridges, including biodiversity hotspots like seamounts and hydrothermal vents. Deep-sea hydrothermal vents are usually associated with a highly specialized fauna, and since their discovery in 1977 more than 400 species of animals have been described. This fauna includes various animal groups of which the most conspicuous and well known are annelids, mollusks and crustaceans. The newly discovered deep sea hydrothermal vents on the Mohns-Knipovich ridge north of Iceland harbour unique biodiversity. The Jan Mayen field consists of two main areas with high-temperature white smoker venting and wide areas with low-temperature seepage, located at 5-700 m, while the deeper Loki Castle vent field at 2400 m depth consists of a large area with high temperature black smokers surrounded by a sedimentary area with more diffuse low-temperature venting and barite chimneys. The Jan Mayen sites show low abundance of specialized hydrothermal vent fauna. Single groups have a few specialized representatives but groups otherwise common in hydrothermal vent areas are absent. Slightly more than 200 macrofaunal species have been identified from this vent area, comprising mainly an assortment of bathyal species known from the surrounding area. Analysis of stable isotope data also indicates that the majority of the species present are feeding on phytodetritus and/or phytoplankton. However, the deeper Loki Castle vent field contains a much more diverse vent endemic fauna with high abundances of specialized polychaetes, gastropods and amphipods. These specializations also include symbioses with a range of chemosynthetic microorganisms. Our data show that the fauna composition is a result of high degree of local specialization with some similarities to the fauna of cold seeps along the Norwegian margin and wood-falls in the abyssal Norwegian Sea

  17. Quantifying the Fluxes of Atmospherically Derived Trace Elements in the Arctic Ocean/Ice System using 7Be

    Science.gov (United States)

    Landing, W. M.; Kadko, D. C.; Shelley, R.; Galfond, B.

    2016-02-01

    Aerosol deposition is an important pathway for delivering biologically-essential and anthropogenically-derived trace elements to the Arctic Ocean. Limited field study in the harsh Arctic environment has forced a reliance on poorly constrained models for the atmospheric deposition of trace elements. Here we use the cosmic ray produced radioisotope 7Be to link aerosol concentrations to flux to the Arctic water/ice system. Seawater, ice, snow, melt pond, and aerosol samples were collected during late summer 2011 as part of the RV Polarstern ARK-XXVI/3 campaign. The average 7Be aerosol loading was 0.018 dpm m-3 and we determined an average 7Be flux of 125 dpm m-2 d-1, consistent with results from previous studies in the region. None of the lithogenic aerosol elements showed any significant enrichment above crustal composition, while the pollution-type elements showed varying degrees of enrichment relative to crustal values. In addition to our own measurements, we use two years of continuous aerosol 7Be and trace element data from the Alert (Canada) monitoring site to generate seasonal and annual estimates for the fluxes of 7Be and trace elements to the Arctic water/ice system. Fluxes of 7Be are 30% higher in Winter (Nov-May) than in Summer (Jun-Oct) due to the strong seasonality in aerosol 7Be concentrations. Fluxes of lithogenic elements (Al, Mn, Fe) are 2-3 times higher in Summer, possibly due to local dust sources on Ellesmere Island. Fluxes of V and Pb are strongly correlated and are 2-3 times higher in Winter, while fluxes of Ni, Cu, and Zn are relatively uniform for both seasons.

  18. Repeated megafloods from glacial Lake Vitim, Siberia, to the Arctic Ocean over the past 60,000 years

    Science.gov (United States)

    Margold, Martin; Jansen, John D.; Codilean, Alexandru T.; Preusser, Frank; Gurinov, Artem L.; Fujioka, Toshiyuki; Fink, David

    2018-05-01

    Cataclysmic outburst floods transformed landscapes and caused abrupt climate change during the last deglaciation. Whether such events have also characterized previous deglaciations is not known. Arctic marine cores hint at megafloods prior to Oxygen Isotope Stage (OIS) 2, but the overprint of successive glaciations means that geomorphological traces of ancient floods remain scarce in Eurasia and North America. Here we present the first well-constrained terrestrial megaflood record to be linked with Arctic archives. Based on cosmogenic-nuclide exposure dating and optically stimulated luminescence dating applied to glacial-lake sediments, a 300-m deep bedrock spillway, and giant eddy-bars > 200-m high, we reconstruct a history of cataclysmic outburst floods from glacial Lake Vitim, Siberia, to the Arctic Ocean over the past 60,000-years. Three megafloods have reflected the rhythm of Eurasian glaciations, leaving traces that stretch more than 3500 km to the Lena Delta. The first flood was coincident with deglaciation from OIS-4 and the largest meltwater spike in Arctic marine-cores within the past 100,000 years (isotope-event 3.31 at 55.5 ka). The second flood marked the lead up to the local Last Glacial Maximum, and the third flood occurred during the last deglaciation. This final 3000 km3 megaflood stands as one of the largest freshwater floods ever documented, with peak discharge of 4.0-6.5 million m3s-1, mean flow depths of 120-150 m, and average flow velocities up to 21 m s-1.

  19. USGS Arctic Ocean carbon cruise 2010: field activity H-03-10-AR to collect carbon data in the Arctic Ocean, August - September 2010

    Science.gov (United States)

    Robbins, Lisa L.; Yates, Kimberly K.; Gove, Matthew D.; Knorr, Paul O.; Wynn, Jonathan; Byrne, Robert H.; Liu, Xuewu

    2013-01-01

    Carbon dioxide (CO2) in the atmosphere is absorbed at the surface of the ocean by reacting with seawater to form carbonic acid, a weak, naturally occurring acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution (Sabine and others, 2004). Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Caldeira and Wickett, 2003; Orr and others, 2005; Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats (Raven and others, 2005; Ruttiman, 2006). The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

  20. USGS Arctic Ocean carbon cruise 2011: field activity H-01-11-AR to collect carbon data in the Arctic Ocean, August - September 2011

    Science.gov (United States)

    Robbins, Lisa L.; Yates, Kimberly K.; Knorr, Paul O.; Wynn, Jonathan; Lisle, John; Buczkowski, Brian J.; Moore, Barbara; Mayer, Larry; Armstrong, Andrew; Byrne, Robert H.; Liu, Xuewu

    2013-01-01

    Carbon dioxide (CO2) in the atmosphere is absorbed at the surface of the ocean by reacting with seawater to form a weak, naturally occurring acid called carbonic acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution (Sabine and others, 2004). Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Caldeira and Wickett, 2003; Orr and others, 2005; Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats (Raven and others, 2005; Ruttiman, 2006). The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

  1. Determination of iridium in the Bering Sea and Arctic Ocean seawaters by anion exchange preconcentration-neutron activation analysis

    International Nuclear Information System (INIS)

    Li Shihong; Mao Xueying; Chai Zhifang

    2004-01-01

    Anion exchange method is investigated to separate and enrich iridium in seawater by radiotracer 192 Ir. The adsorption of Ir in the resin increases with the decreasing acidity in the 0.05-1.2 mol/L HCl media, The recovery of iridium in pH=1.5 seawater reaches 89% by a single anion-exchange column. The polyethylene container of acidity of pH=1.5 are suitable for storing trace Ir in seawater. An anion exchange preconcentration-neutron activation analysis procedure is developed to determine iridium in seawaters sampled from the Bering Sea and Arctic Ocean at different depth. The reagent blank value of the whole procedures is (0.18-0.20) x 10 -12 g Ir. The iridium concentrations in the Bering Sea and Arctic Ocean seawater samples are (0.85-3.58) x 10 -12 g/L (0-3504 m) and (1.26-1.97) x 10 -12 g/L (25-1900 m), respectively

  2. Evolution of biogeochemical cycling of phosphorus during 45~50 Ma revealed by sequential extraction analysis of IODP Expedition 302 cores from the Arctic Ocean

    Science.gov (United States)

    Hashimoto, S.; Yamaguchi, K. E.; Takahashi, K.

    2012-12-01

    The modern Arctic Ocean plays crucial roles in controlling global climate system with the driving force of global thermohaline circulation through the formation of dense deep water and high albedo due to the presence of perennial sea-ice. However, the Arctic sea-ice has not always existed in the past. Integrated Ocean Drilling Program (IODP) Expedition 302 Arctic Coring Expedition (ACEX) has clarified that global warming (water temperature: ca. 14~16○C) during 48~49 Ma Azolla Event induced the loss of sea-ice and desalination of surface ocean, and that sea-ice formed again some million years later (45 Ma). In the Arctic Ocean, warming and cooling events repeated over and over (e.g., Brinkhuis et al., 2006; Moran et al., 2006; März et al., 2010). Large variations in the extent of thermohaline circulation through time often caused stagnation of seawater and appearance of anaerobic environment where hydrogen sulfide was produced by bacterial sulfate reduction. Ogawa et al. (2009) confirmed occurrence of framboidal pyrite in the ACEX sediments, and suggested that the Arctic Ocean at the time was anoxic, analogous to the modern Black Sea, mainly based on sulfur isotope analysis. To further clarify the variations in the nutrient status of the Arctic Ocean, we focus on the geochemical cycle of phosphorus. We performed sequential extraction analysis of sedimentary phosphorus in the ACEX sediments, using the method that we improvped based on the original SEDEX method by Ruttenberg (1992) and Schenau et al. (2000). In our method, phosphorus fractions are divided into five forms; (1) absorbed P, (2) Feoxide-P, (4) carbonate fluorapatite (CFAP) + CaCO3-P + hydroxylapatite (HAP), (4) detrital P, and (5) organic P. Schenau et al. (2000) divided the (3) fraction into non-biological CFAP and biological HAP and CaCO3-P. When the Arctic Ocean was closed and in its warming period, the water mass was most likely stratified and an anaerobic condition would have prevailed where

  3. Observed microphysical changes in Arctic mixed-phase clouds when transitioning from sea ice to open ocean

    Directory of Open Access Journals (Sweden)

    G. Young

    2016-11-01

    Full Text Available In situ airborne observations of cloud microphysics, aerosol properties, and thermodynamic structure over the transition from sea ice to ocean are presented from the Aerosol-Cloud Coupling And Climate Interactions in the Arctic (ACCACIA campaign. A case study from 23 March 2013 provides a unique view of the cloud microphysical changes over this transition under cold-air outbreak conditions. Cloud base lifted and cloud depth increased over the transition from sea ice to ocean. Mean droplet number concentrations, Ndrop, also increased from 110 ± 36 cm−3 over the sea ice to 145 ± 54 cm−3 over the marginal ice zone (MIZ. Downstream over the ocean, Ndrop decreased to 63 ± 30 cm−3. This reduction was attributed to enhanced collision-coalescence of droplets within the deep ocean cloud layer. The liquid water content increased almost four fold over the transition and this, in conjunction with the deeper cloud layer, allowed rimed snowflakes to develop and precipitate out of cloud base downstream over the ocean. The ice properties of the cloud remained approximately constant over the transition. Observed ice crystal number concentrations averaged approximately 0.5–1.5 L−1, suggesting only primary ice nucleation was active; however, there was evidence of crystal fragmentation at cloud base over the ocean. Little variation in aerosol particle number concentrations was observed between the different surface conditions; however, some variability with altitude was observed, with notably greater concentrations measured at higher altitudes ( >  800 m over the sea ice. Near-surface boundary layer temperatures increased by 13 °C from sea ice to ocean, with corresponding increases in surface heat fluxes and turbulent kinetic energy. These significant thermodynamic changes were concluded to be the primary driver of the microphysical evolution of the cloud. This study represents the first investigation, using in situ

  4. Flocculated meltwater particles control Arctic land-sea fluxes of labile iron

    DEFF Research Database (Denmark)

    Markussen, Thor Nygaard; Elberling, Bo; Winter, Christian

    2016-01-01

    Glacial meltwater systems supply the Arctic coastal ocean with large volumes of sediment and potentially bioavailable forms of iron, nitrogen and carbon. The particulate fraction of this supply is significant but estuarine losses have been thought to limit the iron supply from land. Here, our...... the influence of terrestrial hotspots on the nutrient and solute cycles in Arctic coastal waters....

  5. Space-for-time substitution in predicting the state of picoplankton and nanoplankton in a changing Arctic Ocean

    Science.gov (United States)

    Li, William K. W.; Carmack, Eddy C.; McLaughlin, Fiona A.; Nelson, R. John; Williams, William J.

    2013-10-01

    The Arctic Ocean is changing rapidly but there are no long-term time series observations on the state of the phytoplankton community that could allow a link to be made from physical/chemical pressures to the impact on marine ecosystems. Here, we test the idea that space-for-time (SFT) substitution might predict temporal change in the Canada Basin premised on differences in the present state of phytoplankton in other geographic zones, specifically the ratio in the abundance of picophytoplankton to nanophytoplankton (Pico:Nano). We compared the change in Pico:Nano observed in the Canada Basin from 2004 to 2012 to the different average states of this ratio in 26 other ocean ecological regions. Our results show that as upper ocean nitrate concentration changed in the Canada Basin from year to year, the concomitant change in Pico:Nano was statistically commensurate with the difference that this ratio exhibits between Longhurst ecological provinces in relation to nitrate concentration. Lower average concentration of nitrate in the upper water column is associated with a higher value of Pico:Nano, a result consistent with resource control of phytoplankton size structure in the ocean. We suggest that SFT substitution allows an explanation of temporal progression from spatial pattern as a test of mechanism, but such statistical prediction is not necessarily a projection of future states.

  6. A synthesis of light absorption properties of the Pan-Arctic Ocean: application to semi-analytical estimates of dissolved organic carbon concentrations from space

    Science.gov (United States)

    Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Bélanger, S.; Bricaud, A.

    2013-11-01

    The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean (e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012), the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off North America. In contrast, the relationship between the phytoplankton absorption (aφ(λ)) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific aφ(λ) values (Matsuoka et al., 2013), this result indirectly suggests that CDOM absorption can be appropriately derived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC vs. CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

  7. A Synthesis of Light Absorption Properties of the Arctic Ocean: Application to Semi-analytical Estimates of Dissolved Organic Carbon Concentrations from Space

    Science.gov (United States)

    Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Belanger, S.; Bricaud, A.

    2014-01-01

    The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean [e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012], the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher 74 than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained 75 by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian 76 side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off 77 North America. In contrast, the relationship between the phytoplankton absorption (a()) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific a() values [Matsuoka et al., 2013], this result indirectly suggests that CDOM absorption can be appropriately erived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC versus CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

  8. Spatial and temporal scales of sea ice protists and phytoplankton distribution from the gateway Fram Strait into the Central Arctic Ocean

    Science.gov (United States)

    Peeken, I.; Hardge, K.; Krumpen, T.; Metfies, K.; Nöthig, E. M.; Rabe, B.; von Appen, W. J.; Vernet, M.

    2016-02-01

    The Arctic Ocean is currently one of the key regions where the effect of climate change is most pronounced. Sea ice is an important interface in this region by representing a unique habitat for many organisms. Massive reduction of sea ice thickness and extent, which have been recorded over the last twenty years, is anticipated to cause large cascading changes in the entire Arctic ecosystem. Most sea ice is formed on the Eurasian shelves and transported via the Transpolardrift to the western Fram Strait and out of the Arctic Ocean with the cold East Greenland Current (EGC). Warm Atlantic water enters the Arctic Ocean with the West Spitsbergen Current (WSC) via eastern Fram Strait. Here, we focus on the spatial spreading of protists from the Atlantic water masses, and their occurrences over the deep basins of the Central Arctic and the relationship amongst them in water and sea ice. Communities were analyzed by using pigments, flow cytometer and ARISA fingerprints during several cruises with the RV Polarstern to the Fram Strait, the Greenland Sea and the Central Arctic Ocean. By comparing these data sets we are able to demonstrate that the origin of the studied sea ice floes is more important for the biodiversity found in the sea ice communities then the respective underlying water mass. In contrast, biodiversity in the water column is mainly governed by the occurring water masses and the presence or absence of sea ice. However, overall the development of standing stocks in both biomes was governed by the availability of nutrients. To get a temporal perspective of the recent results, the study will be embedded in a long-term data set of phytoplankton biomass obtained during several cruises over the last twenty years.

  9. Effects of sea-ice light attenuation and CDOM absorption in the water below the Eurasian sector of central Arctic Ocean (>88°N)

    NARCIS (Netherlands)

    Lund-Hansen, L.C.; Markager, S.; Hancke, K.; Stratmann, T.; Rysgaard, S.; Ramløv, H.; Sorrell, B.K.

    2015-01-01

    This is a study of the optical, physical and biological parameters of sea ice and the water below it at stations (n=25) in the central (>88°N) Eurasian sector of the Arctic Ocean during the summer 2012 record low sea-ice minimum extent. Results show that photosynthetically active radiation (PAR)

  10. The North Slope of Alaska and Adjacent Arctic Ocean (NSA/AAO) cart site begins operation: Collaboration with SHEBA and FIRE

    Energy Technology Data Exchange (ETDEWEB)

    Zak, D. B.; Church, H.; Ivey, M.; Yellowhorse, L.; Zirzow, J.; Widener, K. B.; Rhodes, P.; Turney, C.; Koontz, A.; Stamnes, K.; Storvold, R.; Eide, H. A.; Utley, P.; Eagan, R.; Cook, D.; Hart, D.; Wesely, M.

    2000-04-04

    Since the 1997 Atmospheric Radiation Measurement (ARM) Science Team Meeting, the North Slope of Alaska and Adjacent Arctic Ocean (NSA/AAO) Cloud and Radiation Testbed (CART) site has come into being. Much has happened even since the 1998 Science Team Meeting at which this paper was presented. To maximize its usefulness, this paper has been updated to include developments through July 1998.

  11. Oil and ice in the arctic ocean: possible large-scale interactions.

    Science.gov (United States)

    Campbell, W J; Martin, S

    1973-07-06

    The diffusion and transport mechanisms generated by the pack ice dynamics of the Beaufort Sea, combined with the slow rate of biodegradation of oil under Arctic conditions, would combine to diffuse an oil spill over the sea and eventually deposit the oil on the ice surface, where it would lower the natural albedo over a large area.

  12. Multimodel simulations of Arctic Ocean sea surface height variability in the period 1970-2009

    DEFF Research Database (Denmark)

    Koldunov, Nikolay V.; Serra, Nuno; Koehl, Armin

    2014-01-01

    analysis of the three time periods 1987-1992, 1993-2002, and 2003-2009, corresponding to the transition times between cyclonic and anticyclonic regimes of the atmospheric circulation over the Arctic, revealed an unusual increase of SSH in the Amerasian basin during 2003-2009. Results from this model...

  13. A modeling experiment on the grounding of an ice shelf in the central Arctic Ocean during MIS 6

    Science.gov (United States)

    Jakobsson, M.; Siegert, M.; Paton, M.

    2003-12-01

    High-resolution chirp sonar subbottom profiles from the Lomonosov Ridge in the central Arctic Ocean, acquired from the Swedish icebreaker Oden in 1996, revealed large-scale erosion of the ridge crest down to depths of 1000 m below present sea level [Jakobsson, 1999]. Subsequent acoustic mapping during the SCICEX nuclear submarine expedition in 1999 showed glacial fluting at the deepest eroded areas and subparallel ice scours from 950 m water depth to the shallowest parts of the ridge crest [Polyak et al., 2001]. The directions of the mapped glaciogenic bed-forms and the redeposition of eroded material on the Amerasian side of the ridge indicate ice flow from the Barents-Kara Sea area. Core studies revealed that sediment drape the eroded areas from Marine Isotope Stage (MIS) 5.5 and, thus, it was proposed that the major erosional event took place during Marine Isotope Stage (MIS) 6 [Jakobsson et al., 2001]. Glacial geological evidence suggests strongly that the Late Saalian (MIS 6) ice sheet margin reached the shelf break of the Barents-Kara Sea [Svendsen et al. in press] and this gives us two possible ways to explain the ice erosional features on the Lomonosov Ridge. One is the grounding of a floating ice shelf and the other is the scouring from large deep tabular iceberg. Here we apply numerical ice sheet modeling to test the hypothesis that an ice shelf emanating from the Barents/Kara seas grounded across part of the Lomonsov Ridge and caused the extensive erosion down to a depth of around 1000 m below present sea level. A series of model experiments was undertaken in which the ice shelf mass balance (surface accumulation and basal melting) and ice shelf strain rates were adjusted. Grounding of the Lomonosov Ridge was not achieved when the ice shelf strain rate was 0.005 yr-1 (i.e. a free flowing ice shelf). However this model produced two interesting findings. First, with basal melt rates of up to 50 cm yr-1 an ice shelf grew from the St. Anna Trough ice stream

  14. Mesoscale dynamics in the Lofoten Basin - a sub-Arctic "hot spot" of oceanic variability

    Science.gov (United States)

    Volkov, D. L.; Belonenko, T. V.; Foux, V. R.

    2012-12-01

    A sub-Arctic "hot spot" of intense mesoscale variability is observed in the Lofoten Basin (LB) - a topographic depression with a maximum depth of about 3250 m, located in the Norwegian Sea. The standard deviation of sea surface height (SSH), measured with satellite altimetry, reaches nearly 15 cm in the center of the basin (Figure 1a). Using a space-time lagged correlation analysis of altimetry data, we discover a cyclonic propagation of the mesoscale SSH anomalies around the center of the LB with time-averaged phase speeds of 2-4 km/day, strongly linked to bottom topography (Figure 1c). The fact that surface drifter trajectories do not exhibit cyclonic circulation in the LB (Figure 1b) suggests that, at least in the upper ocean, satellite altimetry observes only the propagation of form without the corresponding transfer of mass. Linearly propagating wavelike disturbances that do not trap fluid inside are related to planetary or Rossby waves. Variations in topography may lead to the concentration of wave energy in certain regions or wave trapping. The dispersion analysis suggests that the observed wavelike cyclonic propagation of SSH anomalies in the LB is the manifestation of baroclinic topographic Rossby waves, that we term "the basin waves" in order to distinguish them from the other types of topographic waves, such as shelf or trench waves. We identify two modes of basin waves in the LB: a di-pole mode and a quadri-pole mode. The wavelength of each mode is about 500 km. The frequency of these modes is not constant and the phase speed varies from about 2 to 8 km/day. We show that the cyclonically rotating basin waves are responsible for the observed amplification of SSH variability in the LB. Because the baroclinic basin waves in the LB are probably associated with large vertical displacements of the thermocline and due to possible wave breaking events, they can play an important role in the mixing of the inflowing Atlantic Water with ambient water masses

  15. Remotely Sensing Lake Water Volumes on the Inner Arctic Coastal Plain of Northern Alaska

    Science.gov (United States)

    Simpson, C. E.; Arp, C. D.; Jones, B. M.; Hinkel, K. M.; Carroll, M.; Smith, L. C.

    2017-12-01

    Thermokarst lake depth is controlled by the amount of excess ice in near-surface permafrost, with lake depths of about 1 - 3 m in areas of epigenetic permafrost and over 10 m in areas of syngenetic permafrost. An important exception to these general patterns is found on the inner Arctic Coastal Plain (ACP) of northern Alaska, where deep lakes occur in Pleistocene-aged, ground-ice poor sandy terrain. These lakes cover 20% of the currently inactive sand sheet and dune deposit (referred to as the Pleistocene Sand Sea) that comprises approximately 7000 km2 of the ACP. Surrounded by high and eroding bluffs, sand sea lakes lie in natural depressions and are characterized by wide, shallow littoral shelves and central troughs that are typically oriented NNW to SSE and can reach depths greater than 20 m. Despite their unique form and extensive coverage, these lakes have received little prior study and a literature gap remains regarding regional water storage. This research classifies sand sea lakes, estimates individual lake volume, and provides a first quantification of water storage in a region of the lake-dominated ACP. We measured bathymetric profiles in 19 sand sea lakes using a sonar recorder to capture various lake depth gradients. Bathymetric surveys collected by oil industry consultants, lake monitoring programs, and habitat studies serve as additional datasets. These field measured lake depth data points were used to classify Color Infrared Photography, WorldView-2 satellite imagery, and Landsat-OLI satellite imagery to develop a spectral depth-classification algorithm and facilitate the interpolation of the bathymetry for study lakes in the inner ACP. Finally, we integrate the remotely sensed bathymetry and imagery-derived lake surface area to estimate individual and regional-scale lake volume. In addition to the natural function of these lakes in water storage, energy balance, and habitat provision, the need for winter water supply to build ice roads for oil

  16. Transport mechanisms of radioactive substances in the Arctic Ocean. Modelling and experimental studies in the Kara and Barents Seas

    International Nuclear Information System (INIS)

    Nies, H.; Karcher, M.; Bahe, C.; Backhaus, J.; Harms, I.

    1999-03-01

    In 1992, it became known to the public that the former Soviet Union had dumped large amounts of radioactive waste in the Arctic Ocean since about 1959. The waste was dumped into the Kara and Barents Seas in liquid and solid form, sealed in barrels or containers, as reactor parts but also as complete ship reactors including spent fuel. Wrecks of nuclear submarines were dumped near the coast of Novaya Semlya, in depths less than 50 m. The dumping took place in strong contradiction to international rules and conventions. After some confusion and overestimation of the total radioactive inventory, the amount of the waste and the dump site locations are well known, meanwhile. International pressure and the more open information policy of Russia helped to improve the situation. Various international fora primarily within the IAEA and the Arctic Monitoring and Assessment Programme (AMAP) investigated the potential consequences from these dumping practices. This report is the German contribution to these international assessments. The dumped objects in the Kara Sea encompass 17 nuclear ship reactors, seven of them still carrying spent fuel. Four dump sites are located in small and shallow fjords at the east coast of Novaya Semlya, and in the Novaya Semlya Trough, in max. depth of 420 m. The total radioactive inventory was, at the time of dumping, 37 PBq. During the project numerous samples from seawater and sediment were analysed on artificial radionuclides in Arctic waters. This included samples from the Kara Sea but also samples around the Russian nuclear submarine Komsomolets sunk in the Norwegian Sea at a depth of about 1700 m in 1989. Numerical hydrodynamic models in local, regional and global scale were used to predict the potential dispersion of released radionuclides from the dumped wastes and reactors in the Kara Sea. (orig.) [de

  17. Arctic Ice-Ocean Coupling and Gyre Equilibration Observed With Remote Sensing

    Science.gov (United States)

    Dewey, Sarah; Morison, James; Kwok, Ronald; Dickinson, Suzanne; Morison, David; Andersen, Roger

    2018-02-01

    Model and observational evidence has shown that ocean current speeds in the Beaufort Gyre have increased and recently stabilized. Because these currents rival ice drift speeds, we examine the potential for the Beaufort Gyre's shift from a system in which the wind drives the ice and the ice drives a passive ocean to one in which the ocean often, in the absence of high winds, drives the ice. The resultant stress exerted on the ocean by the ice and the resultant Ekman pumping are reversed, without any change in average wind stress curl. Through these curl reversals, the ice-ocean stress provides a key feedback in Beaufort Gyre stabilization. This manuscript constitutes one of the first observational studies of ice-ocean stress inclusive of geostrophic ocean currents, by making use of recently available remote sensing data.

  18. Sources and fate of chromophoric dissolved organic matter and water mass ventilation in the upper Arctic Ocean

    Science.gov (United States)

    Walker, S. A.; Amon, R. M.; Stedmon, C. A.

    2011-12-01

    The majority of high latitude soil organic carbon is stored within vast permafrost regions surrounding the Arctic, which are highly susceptible to climate change. As global warming persists increased river discharge combined with permafrost erosion and extended ice free periods will increase the supply of soil organic carbon to the Arctic Ocean. Increased river discharge to the Arctic will also have a significant impact its hydrological cycle and could potentially be critical to sea ice formation. This impact is due to freshwater discharge to the Arctic which has been shown to help sustain halocline formation, a critical water mass that acts as an insulator trapping heat from inflowing Atlantic waters from ice at the surface. As the climate warms it is therefore important to identify halocline source waters and to determine fluctuations in their contribution to this critical water mass. To better understand dissolved organic matter (DOM) quality and its fate within the Arctic as well as runoff distributions across the basin the optical properties of chromophoric dissolved organic carbon (CDOM) were evaluated during a trans-Arctic expedition, AOS 2005. This cruise is unique because it is the first time fluorescence data have been obtained from all basins in the Arctic. Excitation/Emission Matrix Spectroscopy (EEM's) coupled to Parallel Factor Analysis (PARAFAC) was used to decompose the combined CDOM fluorescence signal into six independent components that can be traced to a source. Three humic-like CDOM components were isolated and linked to runoff waters using Principal Component Analysis (PCA). Inherent differences were observed between Eurasian (EB) and Canadian (CB) basin surface waters in terms of DOM quality and freshwater distributions. In EB surface waters (0-50m) the humic-like CDOM components explained roughly half of the variance in the DOC pool and were strongly related to lignin phenol concentrations. These results indicate CDOM in Trans-Polar Drift

  19. Greater Role of Geostrophic Currents on Ekman Dynamics in the Western Arctic Ocean as a Mechanism for Beaufort Gyre Stabilization

    Science.gov (United States)

    Steele, M.; Zhong, W.; Zhang, J.; Zhao, J.

    2017-12-01

    Seven different methods, with and without including geostrophic currents, were used to explore Ekman dynamics in the western Arctic Ocean for the period 1992-2014. Results show that surface geostrophic currents have been increasing and are much stronger than Ekman layer velocities in recent years (2003-2014) when the oceanic Beaufort Gyre (BG) is spinning up in the region. The new methods that include geostrophic currents result in more realistic Ekman pumping velocities than a previous iterative method that does not consider geostrophic currents and therefore overestimates Ekman pumping velocities by up to 52% in the central area of the BG over the period 2003-2014. When the BG is spinning up as seen in recent years, geostrophic currents become stronger, which tend to modify the ice-ocean stress and to cause an Ekman divergence that counteracts wind-driven Ekman convergence in the Canada Basin. This is a mechanism we have identified to play an important and growing role in stabilizing the Ekman convergence and therefore the BG in recent years. This mechanism may be used to explain three scenarios that describe the interplay of changes in wind forcing, sea ice motion, and geostrophic currents that control the variability of the Ekman dynamics in the central BG during 1992-2014. Results also reveal several upwelling regions in the southern and northern Canada Basin and the Chukchi Abyssal Plain which may plays a significant role in biological processes in these regions.

  20. New paleomagnetic poles from Arctic Siberia support Indian Ocean option for the Neoproterozoic APWP of the Siberian craton.

    Science.gov (United States)

    Pasenko, A.; Malyshev, S. V.

    2017-12-01

    Quantity and quality of paleomagnetic poles obtained so far for Neoproterozoic of Siberia are still insufficient even to outline the general trend of APWP of Siberia for this huge and very interesting time interval. Meanwhile, the solution of this problem is crucial for choice of polarity option for Siberian proterozoic paleomagnetic directions, for construction and testing of world paleotectonic and paleogeographic reconstructions. For example, whether or not the Siberian craton could be connected with Laurentia within the supercontinent Rodinia depends directly on paleomagnetic polarity option choice, which , in its turn, is determined by either we choose for neoproterozoic drift of Siberian paleomagnetic poles Pacific ocean trend [Smethurst et al., 1998] or Indian ocean [Pavlov et al., 2015] trend. To advance in solution of this problem we have carried out the paleomagnetic investigations of several sedimentary sections and sills of Arctic Siberia considered to be meso-neoproterozoic in age. In particular we have studied the terrigenous Udza and Unguohtah Formations and basic sills of the Udzha Uplift; the carbonate Khaipakh Formation of the Olenek Uplift; the carbonate Burovaya Formation of the Turukhansk Uplift; basic sills of the Kparaulakh Mountains.In this report we present the paleomagnetic poles obtained, discuss their bearing on construction of the adequate Siberian neoproterozoic APWP and show that our new data rather support the Indian ocean option.This research were supported by Grant from RF President #MK-739.2017.5

  1. Greater Role of Geostrophic Currents in Ekman Dynamics in the Western Arctic Ocean as a Mechanism for Beaufort Gyre Stabilization

    Science.gov (United States)

    Zhong, Wenli; Steele, Michael; Zhang, Jinlun; Zhao, Jinping

    2018-01-01

    Seven different methods, with and without including geostrophic currents, were used to explore Ekman dynamics in the western Arctic Ocean for the period 1992-2014. Results show that surface geostrophic currents have been increasing and are much stronger than Ekman layer velocities in recent years (2003-2014) when the oceanic Beaufort Gyre (BG) is spinning up in the region. The new methods that include geostrophic currents result in more realistic Ekman pumping velocities than a previous iterative method that does not consider geostrophic currents and therefore overestimates Ekman pumping velocities by up to 52% in the central area of the BG over the period 2003-2014. When the BG is spinning up as seen in recent years, geostrophic currents become stronger, which tend to modify the ice-ocean stress and moderate the wind-driven Ekman convergence in the Canada Basin. This is a mechanism we have identified to play an important and growing role in stabilizing the Ekman convergence and therefore the BG in recent years. This mechanism may be used to explain three scenarios that describe the interplay of changes in wind forcing, sea ice motion, and geostrophic currents that control the variability of the Ekman dynamics in the central BG during 1992-2014. Results also reveal several upwelling regions in the southern and northern Canada Basin and the Chukchi Abyssal Plain which may play a significant role in physical and biological processes in these regions.

  2. Application of Natural Radioisotopes as Tracers of Particulate Organic Carbon Transport, Export and Burial Processes in Chukchi Sea, Arctic Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Yu; Jianhua, He [Key Lab of Global Change and Marine-Atmosphere Chemistry, State Oceanic Administration, Xiamen (China)

    2013-07-15

    To evaluate the efficiency of the biological pump and carbon sequestration content on the Arctic shelf, estimations of POC export fluxes derived from 234Th/238U disequilibrium and organic carbon burial rate from 210Pbex chronology in sediment core were made during the 3rd Chinese National Arctic Research Expedition (CHINARE-3), Jul 12-Sep 22, 2008. Great deficits of {sup 234}Th to {sup 238}U were observed widely over the Chukchi shelf, with an average {sup 234}Th/{sup 238}U of 0.64{+-}0.28, resulting from intense particle scavenging. The average POC export fluxes in the entire study area, shelf and slope area were 24.9 {+-} 23.3, 29.5 {+-} 23.0 and 2.1 {+-} 0.5 mmol C/m{sup 2}d, respectively, i.e. 21% of the primary production on average was exported to the benthos. An organic carbon burial rate of 517 mmol C/m{sup 2}a were estimated, accounting for 6% of the average primary production. The efficient biological pump led to 11.6{+-}9.0 T g C exported to benthos and 3.4 T g C buried permanently in the sediment per year, accounting for 0.3% of total POC export amount and 2.1% of total organic carbon burial amount of the global ocean. (author)

  3. Near-Surface Meteorology During the Arctic Summer Cloud Ocean Study (ASCOS): Evaluation of Reanalyses and Global Climate Models.

    Science.gov (United States)

    De Boer, G.; Shupe, M.D.; Caldwell, P.M.; Bauer, Susanne E.; Persson, O.; Boyle, J.S.; Kelley, M.; Klein, S.A.; Tjernstrom, M.

    2014-01-01

    Atmospheric measurements from the Arctic Summer Cloud Ocean Study (ASCOS) are used to evaluate the performance of three atmospheric reanalyses (European Centre for Medium Range Weather Forecasting (ECMWF)- Interim reanalysis, National Center for Environmental Prediction (NCEP)-National Center for Atmospheric Research (NCAR) reanalysis, and NCEP-DOE (Department of Energy) reanalysis) and two global climate models (CAM5 (Community Atmosphere Model 5) and NASA GISS (Goddard Institute for Space Studies) ModelE2) in simulation of the high Arctic environment. Quantities analyzed include near surface meteorological variables such as temperature, pressure, humidity and winds, surface-based estimates of cloud and precipitation properties, the surface energy budget, and lower atmospheric temperature structure. In general, the models perform well in simulating large-scale dynamical quantities such as pressure and winds. Near-surface temperature and lower atmospheric stability, along with surface energy budget terms, are not as well represented due largely to errors in simulation of cloud occurrence, phase and altitude. Additionally, a development version of CAM5, which features improved handling of cloud macro physics, has demonstrated to improve simulation of cloud properties and liquid water amount. The ASCOS period additionally provides an excellent example of the benefits gained by evaluating individual budget terms, rather than simply evaluating the net end product, with large compensating errors between individual surface energy budget terms that result in the best net energy budget.

  4. The conservative behavior of dissolved organic carbon in surface waters of the southern Chukchi Sea, Arctic Ocean, during early summer.

    Science.gov (United States)

    Tanaka, Kazuki; Takesue, Nobuyuki; Nishioka, Jun; Kondo, Yoshiko; Ooki, Atsushi; Kuma, Kenshi; Hirawake, Toru; Yamashita, Youhei

    2016-09-23

    The spatial distribution of dissolved organic carbon (DOC) concentrations and the optical properties of dissolved organic matter (DOM) determined by ultraviolet-visible absorbance and fluorescence spectroscopy were measured in surface waters of the southern Chukchi Sea, western Arctic Ocean, during the early summer of 2013. Neither the DOC concentration nor the optical parameters of the DOM correlated with salinity. Principal component analysis using the DOM optical parameters clearly separated the DOM sources. A significant linear relationship was evident between the DOC and the principal component score for specific water masses, indicating that a high DOC level was related to a terrigenous source, whereas a low DOC level was related to a marine source. Relationships between the DOC and the principal component scores of the surface waters of the southern Chukchi Sea implied that the major factor controlling the distribution of DOC concentrations was the mixing of plural water masses rather than local production and degradation.

  5. Distribution and air-sea exchange of current-use pesticides (CUPs) from East Asia to the high Arctic Ocean.

    Science.gov (United States)

    Zhong, Guangcai; Xie, Zhiyong; Cai, Minghong; Möller, Axel; Sturm, Renate; Tang, Jianhui; Zhang, Gan; He, Jianfeng; Ebinghaus, Ralf

    2012-01-03

    Surface seawater and marine boundary layer air samples were collected on the ice-breaker R/V Xuelong (Snow Dragon) from the East China Sea to the high Arctic (33.23-84.5° N) in July to September 2010 and have been analyzed for six current-use pesticides (CUPs): trifluralin, endosulfan, chlorothalonil, chlorpyrifos, dacthal, and dicofol. In all oceanic air samples, the six CUPs were detected, showing highest level (>100 pg/m(3)) in the Sea of Japan. Gaseous CUPs basically decreased from East Asia (between 36.6 and 45.1° N) toward Bering and Chukchi Seas. The dissolved CUPs in ocean water ranged widely from air. Trifluralin in seawater was relatively high in the Sea of Japan (35.2° N) and evenly distributed between 36.9 and 72.5° N, but it remained below the detection limit at the highest northern latitudes in Chukchi Sea. In contrast with other CUPs, concentrations of chlorothalonil and dacthal were more abundant in Chukchi Sea and in East Asia. The air-sea gas exchange of CUPs was generally dominated by net deposition. Latitudinal trends of fugacity ratios of α-endosulfan, chlorothalonil, and dacthal showed stronger deposition of these compounds in East Asia than in Chukchi Sea, while trifluralin showed stronger deposition in Chukchi Sea (-455 ± 245 pg/m(2)/day) than in the North Pacific (-241 ± 158 pg/m(2)/day). Air-sea gas exchange of chlorpyrifos varied from net volatilizaiton in East Asia (<40° N) to equilibrium or net deposition in the North Pacific and the Arctic.

  6. Microbial biomass and viral infections of heterotrophic prokaryotes in the sub-surface layer of the central Arctic Ocean

    Science.gov (United States)

    Steward, Grieg F.; Fandino, Laura B.; Hollibaugh, James T.; Whitledge, Terry E.; Azam, Farooq

    2007-10-01

    Seawater samples were collected for microbial analyses between 55 and 235 m depth across the Arctic Ocean during the SCICEX 97 expedition (03 September-02 October 1997) using a nuclear submarine as a research platform. Abundances of prokaryotes (range 0.043-0.47×10 9 dm -3) and viruses (range 0.68-11×10 9 dm -3) were correlated ( r=0.66, n=150) with an average virus:prokaryote ratio of 26 (range 5-70). Biomass of prokaryotes integrated from 55 to 235 m ranged from 0.27 to 0.85 g C m -2 exceeding that of phytoplankton (0.005-0.2 g C m -2) or viruses (0.02-0.05 g C m -2) over the same depth range by an order of magnitude on average. Using transmission electron microscopy (TEM), we estimated that 0.5% of the prokaryote community on average (range 0-1.4%) was visibly infected with viruses, which suggests that very little of prokaryotic secondary production was lost due to viral lysis. Intracellular viruses ranged from 5 to >200/cell, with an average apparent burst size of 45±38 (mean±s.d.; n=45). TEM also revealed the presence of putative metal-precipitating bacteria in 8 of 13 samples, which averaged 0.3% of the total prokaryote community (range 0-1%). If these prokaryotes are accessible to protistan grazers, the Fe and Mn associated with their capsules might be an important source of trace metals to the planktonic food web. After combining our abundance and mortality data with data from the literature, we conclude that the biomass of prokaryoplankton exceeds that of phytoplankton when averaged over the upper 250 m of the central Arctic Ocean and that the fate of this biomass is poorly understood.

  7. Is there a see-saw over an ice-free Arctic Ocean?

    Science.gov (United States)

    Stendel, Martin; Yang, Shuting; Langen, Peter; Rodehacke, Christian; Mottram, Ruth; Hesselbjerg Christensen, Jens

    2017-04-01

    The "see-saw" in winter temperatures between western Greenland and the Canadian Arctic on one side and northern Europe on the other has been described by Loewe already in 1937, but actually this behaviour was at least known since the Danish colonization of Greenland in the early 18th century. The see-saw is associated with pressure anomalies not only near the region of interest, but as remote as the Mediterranean and the North Pacific. Recent research has pointed out the role of sea ice in maintaining the see-saw in either its warm or its cold phase over extended periods, which strongly affects European winter temperatures. What would happen to the seesaw if Arctic sea ice were to disappear suddenly? In the framework of the FP7-funded project ice2ice, we try to answer this and related questions. We have conducted a very long global simulation with a global climate model interactively coupled to a Greenland ice sheet component, covering the period 1850-3250 at a horizontal resolution of approximately 125 km. Up to 2005, the forcing is from observed greenhouse gas concentrations, and from 2006 onward it follows the extended RCP8.5 scenario, in which greenhouse gas concentrations continue to increase and eventually level out around 2250. With such a strong forcing, all Arctic sea ice has completely disappeared by roughly the same time, and the surface mass balance of the Greenland Ice Sheet becomes strongly negative. We investigate how the see-saw behaves in such an ice-free world and which implications circulation changes have in the Arctic and over Europe. To further elucidate the role of sea ice distribution on the atmospheric flow and the role of surface fluxes in maintaining the Greenland-European see-saw, we intend at a later time to expand our analysis to include a contrasting simulation with both western Greenland and northern Europe covered by ice during the Last Glacier Maximum.

  8. Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 4, Volume IV: Inherent Optical Properties: Instruments, Characterizations, Field Measurements and Data Analysis Protocols

    Science.gov (United States)

    Mueller, J. L.; Fargion, G. S.; McClain, C. R. (Editor); Pegau, S.; Zanefeld, J. R. V.; Mitchell, B. G.; Kahru, M.; Wieland, J.; Stramska, M.

    2003-01-01

    This document stipulates protocols for measuring bio-optical and radiometric data for the Sensor Intercomparision and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities and algorithm development. The document is organized into 6 separate volumes as Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 4. Volume I: Introduction, Background, and Conventions; Volume II: Instrument Specifications, Characterization and Calibration; Volume III: Radiometric Measurements and Data Analysis Methods; Volume IV: Inherent Optical Properties: Instruments, Characterization, Field Measurements and Data Analysis Protocols; Volume V: Biogeochemical and Bio-Optical Measurements and Data Analysis Methods; Volume VI: Special Topics in Ocean Optics Protocols and Appendices. The earlier version of Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 3 is entirely superseded by the six volumes of Revision 4 listed above.

  9. Baseline monitoring of the western Arctic Ocean estimates 20% of the Canadian Basin surface waters are undersaturated with respect to aragonite

    Science.gov (United States)

    Robbins, Lisa L.; Wynn, Jonathan G.; Lisle, John T.; Yates, Kimberly K.; Knorr, Paul O.; Byrne, Robert H.; Liu, Xuewu; Patsavas, Mark C.; Azetsu-Scott, Kumiko; Takahashi, Taro

    2013-01-01

    Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index) for the western Arctic Ocean. This data set documents aragonite undersaturation in ~20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean’s largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater.

  10. Perfluoroalkyl acids in surface seawater from the North Pacific to the Arctic Ocean: Contamination, distribution and transportation.

    Science.gov (United States)

    Li, Lei; Zheng, Hongyuan; Wang, Tieyu; Cai, Minghong; Wang, Pei

    2018-03-16

    The bioaccumulative, persistent and toxic properties of long-chain perfluoroalkyl acids (PFAAs) resulted in strict regulations on PFAAs, especially in developed countries. Consequently, the industry manufacturing of PFAAs shifts from long-chain to short-chain. In order to better understand the pollution situation of PFAAs in marine environment under this new circumstance, the occurrence of 17 linear PFAAs was investigated in 30 surface seawater samples from the North Pacific to Arctic Ocean (123°E to 24°W, 32 to 82°N) during the sixth Chinese Arctic Expedition in 2014. Total concentrations of PFAAs (∑PFAAs) were between 346.9 pg per liter (pg/L) to 3045.3 pg/L. The average concentrations of ∑PFAAs decreased in the order of East China Sea (2791.4 pg/L, n = 2), Sea of Japan (East Sea) (832.8 pg/L, n = 6), Arctic Ocean (516.9 pg/L, n = 7), Chukchi Sea (505.2 pg/L, n = 4), Bering Sea (501.2 pg/L, n = 8) and Sea of Okhotsk (417.7 pg/L, n = 3). C4 to C9 perfluoroalkyl carboxylic acids (PFCAs) were detected in more than 80% of the surface water samples. Perfluorobutanoic acid (PFBA) was the most prevalent compound and perfluorooctanoic acid (PFOA) was the second abundant homolog. The concentration of individual PFAAs in the surface seawater of East China Sea was much higher than other sampling seas. As the spatial distribution of PFAAs in the marine environment was mainly influenced by the river inflow from the basin countries, which proved the large input from China. Furthermore, the marginal seas of China were found with the greatest burden of PFOA comparing the pollution level in surface seawater worldwide. PFBA concentration in the surrounding seas of China was also high, but distributed more evenly with an obvious increase in recent years. This large-scale monitoring survey will help the improvement and development of PFAAs regulations and management, where production shift should be taken into consideration. Copyright

  11. Parameterization of vertical chlorophyll a in the Arctic Ocean: impact of the subsurface chlorophyll maximum on regional, seasonal, and annual primary production estimates

    Directory of Open Access Journals (Sweden)

    M. Ardyna

    2013-06-01

    Full Text Available Predicting water-column phytoplankton biomass from near-surface measurements is a common approach in biological oceanography, particularly since the advent of satellite remote sensing of ocean color (OC. In the Arctic Ocean, deep subsurface chlorophyll maxima (SCMs that significantly contribute to primary production (PP are often observed. These are neither detected by ocean color sensors nor accounted for in the primary production models applied to the Arctic Ocean. Here, we assemble a large database of pan-Arctic observations (i.e., 5206 stations and develop an empirical model to estimate vertical chlorophyll a (Chl a according to (1 the shelf–offshore gradient delimited by the 50 m isobath, (2 seasonal variability along pre-bloom, post-bloom, and winter periods, and (3 regional differences across ten sub-Arctic and Arctic seas. Our detailed analysis of the dataset shows that, for the pre-bloom and winter periods, as well as for high surface Chl a concentration (Chl asurf; 0.7–30 mg m−3 throughout the open water period, the Chl a maximum is mainly located at or near the surface. Deep SCMs occur chiefly during the post-bloom period when Chl asurf is low (0–0.5 mg m−3. By applying our empirical model to annual Chl asurf time series, instead of the conventional method assuming vertically homogenous Chl a, we produce novel pan-Arctic PP estimates and associated uncertainties. Our results show that vertical variations in Chl a have a limited impact on annual depth-integrated PP. Small overestimates found when SCMs are shallow (i.e., pre-bloom, post-bloom > 0.7 mg m−3, and the winter period somehow compensate for the underestimates found when SCMs are deep (i.e., post-bloom −3. SCMs are, however, important seasonal features with a substantial impact on depth-integrated PP estimates, especially when surface nitrate is exhausted in the Arctic Ocean and where highly stratified and oligotrophic conditions prevail.

  12. Arctic ocean acidification: pelagic ecosystem and biogeochemical responses during a mesocosm study

    NARCIS (Netherlands)

    Riebesell, U.; Gattuso, J.-P.; Thingstad, T.F.; Middelburg, J.J.

    2013-01-01

    The growing evidence of potential biological impacts of ocean acidification affirms that this global change phenomenon may pose a serious threat to marine organisms and ecosystems. Whilst ocean acidification will occur everywhere, it will happen more rapidly in some regions than in others. Due

  13. Community respiration/production and bacterial activity in the upper water column of the central Arctic Ocean

    Science.gov (United States)

    Sherr, Barry F.; Sherr, Evelyn B.

    2003-04-01

    Community metabolism (respiration and production) and bacterial activity were assessed in the upper water column of the central Arctic Ocean during the SHEBA/JOIS ice camp experiment, October 1997-September 1998. In the upper 50 m, decrease in integrated dissolved oxygen (DO) stocks over a period of 124 d in mid-winter suggested a respiration rate of ˜3.3 nM O 2 h -1 and a carbon demand of ˜4.5 gC m -2. Increase in 0-50 m integrated stocks of DO during summer implied a net community production of ˜20 gC m -2. Community respiration rates were directly measured via rate of decrease in DO in whole seawater during 72-h dark incubation experiments. Incubation-based respiration rates were on average 3-fold lower during winter (11.0±10.6 nM O 2 h -1) compared to summer (35.3±24.8 nM O 2 h -1). Bacterial heterotrophic activity responded strongly, without noticeable lag, to phytoplankton growth. Rate of leucine incorporation by bacteria (a proxy for protein synthesis and cell growth) increased ˜10-fold, and the cell-specific rate of leucine incorporation ˜5-fold, from winter to summer. Rates of production of bacterial biomass in the upper 50 m were, however, low compared to other oceanic regions, averaging 0.52±0.47 ngC l -1 h -1 during winter and 5.1±3.1 ngC l -1 h -1 during summer. Total carbon demand based on respiration experiments averaged 2.4±2.3 mgC m -3 d -1 in winter and 7.8±5.5 mgC m -3 d -1 in summer. Estimated bacterial carbon demand based on bacterial productivity and an assumed 10% gross growth efficiency was much lower, averaging about 0.12±0.12 mgC m -3 d -1 in winter and 1.3±0.7 mgC m -3 d -1 in summer. Our estimates of bacterial activity during summer were an order of magnitude less than rates reported from a summer 1994 study in the central Arctic Ocean, implying significant inter-annual variability of microbial processes in this region.

  14. Temperature and salinity data collected by XCTD in the Arctic Ocean from the USS L. Mendel Rivers in October 2000 and USS Honolulu in October 2003 (NODC Accession 0119953)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  15. Temperature profile data collected aboard the USCGC Polar Star in support of investigations of the influence of the Mendeleev Ridge and Chukchi Borderland on the large-scale circulation of the Arctic Ocean, August - September 2002 (NODC Accession 0002697)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is an archive of data of 47 distinct XBT casts taken at 41 locations in the Mendeleev Ridge and Chukchi Borderland region of the Arctic between 22nd August and...

  16. Pelagic community production and carbon-nutrient stoichiometry under variable ocean acidification in an Arctic fjord

    Directory of Open Access Journals (Sweden)

    A. Silyakova

    2013-07-01

    Full Text Available Net community production (NCP and carbon to nutrient uptake ratios were studied during a large-scale mesocosm experiment on ocean acidification in Kongsfjorden, western Svalbard, during June–July 2010. Nutrient depleted fjord water with natural plankton assemblages, enclosed in nine mesocosms of ~ 50 m3 in volume, was exposed to pCO2 levels ranging initially from 185 to 1420 μatm. NCP estimations are the cumulative change in dissolved inorganic carbon concentrations after accounting for gas exchange and total alkalinity variations. Stoichiometric coupling between inorganic carbon and nutrient net uptake is shown as a ratio of NCP to a cumulative change in inorganic nutrients. Phytoplankton growth was stimulated by nutrient addition half way through the experiment and three distinct peaks in chlorophyll a concentration were observed during the experiment. Accordingly, the experiment was divided in three phases. Cumulative NCP was similar in all mesocosms over the duration of the experiment. However, in phases I and II, NCP was higher and in phase III lower at elevated pCO2. Due to relatively low inorganic nutrient concentration in phase I, C : N and C : P uptake ratios were calculated only for the period after nutrient addition (phase II and phase III. For the total post-nutrient period (phase II + phase III ratios were close to Redfield, however they were lower in phase II and higher in phase III. Variability of NCP, C : N and C : P uptake ratios in different phases reflects the effect of increasing CO2 on phytoplankton community composition and succession. The phytoplankton community was composed predominantly of haptophytes in phase I, prasinophytes, dinoflagellates, and cryptophytes in phase II, and haptophytes, prasinophytes, dinoflagellates and chlorophytes in phase III (Schulz et al., 2013. Increasing ambient inorganic carbon concentrations have also been shown to promote primary production and carbon assimilation. For this study, it is

  17. 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 ODEN in the Arctic Ocean, Barents Sea and others from 2002-04-20 to 2002-06-06 (NODC Accession 0113590)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113590 includes chemical, discrete sample, physical and profile data collected from ODEN in the Arctic Ocean, Barents Sea, North Atlantic Ocean and...

  18. International Bathymetric Chart of the Arctic Ocean, Version 2.23

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of this initiative is to develop a digital data base that contains all available bathymetric data north of 64 degrees North, for use by mapmakers,...

  19. Environmental Working Group Joint U.S.-Russian Atlas of the Arctic Ocean

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Environmental Working Group (EWG) was established in June 1995 under the framework of the U.S.-Russian Joint Commission on Economic and Technological...

  20. International Bathymetric Chart of the Arctic Ocean, Version 1.0

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of this initiative is to develop a digital data base that contains all available bathymetric data north of 64 degrees North, for use by mapmakers,...

  1. Late winter under ice pelagic microbial communities in the high Arctic Ocean and the impact of short-term exposure to elevated CO2 levels

    Directory of Open Access Journals (Sweden)

    Adam eMonier

    2014-09-01

    Full Text Available Polar Oceans are natural CO2 sinks because of the enhanced solubility of CO2 in cold water. The Arctic Ocean is at additional risk of accelerated ocean acidification (OA because of freshwater inputs from sea ice and rivers, which influence the carbonate system. Winter conditions in the Arctic are of interest because of both cold temperatures and limited CO2 venting to the atmosphere when sea ice is present. Earlier OA experiments on Arctic microbial communities conducted in the absence of ice cover, hinted at shifts in taxa dominance and diversity under lowered pH. The Catlin Arctic Survey provided an opportunity to conduct in situ, under-ice, OA experiments during late Arctic winter. Seawater was collected from under the sea ice off Ellef Ringnes Island, and communities were exposed to three CO2 levels for 6 days. Phylogenetic diversity was greater in the attached fraction compared to the free-living fraction in situ, in the controls and in the treatments. The dominant taxa in all cases were Gammaproteobacteria but acidification had little effect compared to the effects of containment. Phylogenetic net relatedness indices suggested that acidification may have decreased the diversity within some bacterial orders, but overall there was no clear trend. Within the experimental communities, alkalinity best explained the variance among samples and replicates, suggesting subtle changes in the carbonate system need to be considered in such experiments. We conclude that under ice communities have the capacity to respond either by selection or phenotypic plasticity to heightened CO2 levels over the short term.

  2. An Assessment of State-of-the-Art Mean Sea Surface and Geoid Models of the Arctic Ocean: Implications for Sea Ice Freeboard Retrieval

    Science.gov (United States)

    Skourup, Henriette; Farrell, Sinéad Louise; Hendricks, Stefan; Ricker, Robert; Armitage, Thomas W. K.; Ridout, Andy; Andersen, Ole Baltazar; Haas, Christian; Baker, Steven

    2017-11-01

    State-of-the-art Arctic Ocean mean sea surface (MSS) models and global geoid models (GGMs) are used to support sea ice freeboard estimation from satellite altimeters, as well as in oceanographic studies such as mapping sea level anomalies and mean dynamic ocean topography. However, errors in a given model in the high-frequency domain, primarily due to unresolved gravity features, can result in errors in the estimated along-track freeboard. These errors are exacerbated in areas with a sparse lead distribution in consolidated ice pack conditions. Additionally model errors can impact ocean geostrophic currents, derived from satellite altimeter data, while remaining biases in these models may impact longer-term, multisensor oceanographic time series of sea level change in the Arctic. This study focuses on an assessment of five state-of-the-art Arctic MSS models (UCL13/04 and DTU15/13/10) and a commonly used GGM (EGM2008). We describe errors due to unresolved gravity features, intersatellite biases, and remaining satellite orbit errors, and their impact on the derivation of sea ice freeboard. The latest MSS models, incorporating CryoSat-2 sea surface height measurements, show improved definition of gravity features, such as the Gakkel Ridge. The standard deviation between models ranges 0.03-0.25 m. The impact of remaining MSS/GGM errors on freeboard retrieval can reach several decimeters in parts of the Arctic. While the maximum observed freeboard difference found in the central Arctic was 0.59 m (UCL13 MSS minus EGM2008 GGM), the standard deviation in freeboard differences is 0.03-0.06 m.

  3. Variability of the Arctic Basin Oceanographic Fields

    National Research Council Canada - National Science Library

    Sabinin, K

    1996-01-01

    ...." Special attention was paid to Atlantic Water in the Arctic Ocean which seems to be the main source of information in acoustic monitoring of the ocean, in the framework of the Arctic-ATOC program...

  4. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from AIRCRAFT, ARCTIC IVIK and others in the Arctic Ocean, Baffin Bay and others from 1974-08-11 to 2009-10-15 (NODC Accession 0116709)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116709 includes biological, chemical, discrete sample, physical and profile data collected from AIRCRAFT, ARCTIC IVIK, Amundsen, HENRY LARSEN, JOHN...

  5. Reflection and transmission of irradiance by snow and sea ice in the central Arctic Ocean in summer 2010

    Directory of Open Access Journals (Sweden)

    Ruibo Lei

    2012-03-01

    Full Text Available Reflection and transmission of irradiance by the combined snow and sea ice layer were measured at an ice camp (ca. 10 days and several short-term stations (ca. 2 h established in the western sector of the Arctic Ocean above 80°N during the 2010 summer. These measurements were made with an intention to quantify the apparent optical properties of snow and sea ice, and to evaluate their roles in the mass balance of snow-covered sea ice in the High Arctic. The integrated 350–920 nm albedo ranged from 0.54 to 0.88, and was primarily dependent on the geophysical properties of snow, but not those of sea ice. This implies that all snow cover was still optically thick, even though snow melting had commenced at all measurement sites. For sea ice about 1.66 m thick and covered by 2.5–8.5 cm of snow at the ice camp, the integrated 350–920 nm transmittance ranged from 0.017 to 0.065. Rapid snow melting resulting from an event of slight drizzle doubled the available solar irradiance under the ice (from ca. 3.6 to 7.2 W·m−2, which further accelerated ice-bottom decay. During the measurement at the camp, the temporally averaged incident solar irradiance at 320–950 nm was 110.6±33.6 W·m−2, 29.2±2.9% of which was absorbed by snow and sea ice and utilized to melt snow and sea ice. The melting of snow and sea ice had a distinctly greater effect on the spectral reflection and transmission for the near-infrared spectrum than for the ultraviolet and visible spectra.

  6. Late Eocene to present isotopic (Sr-Nd-Pb) and geochemical evolution of sediments from the Lomonosov Ridge, Arctic Ocean: Implications for continental sources and linkage with the North Atlantic Ocean

    Science.gov (United States)

    Stevenson, Ross; Poirier, André; Véron, Alain; Carignan, Jean; Hillaire-Marcel, Claude

    2015-09-01

    New geochemical and isotopic (Sr, Nd, Pb) data are presented for a composite sedimentary record encompassing the past 50 Ma of history of sedimentation on the Lomonosov Ridge in the Arctic Ocean. The sampled sediments encompass the transition of the Arctic basin from an enclosed anoxic basin to an open and ventilated oxidized ocean basin. The transition from anoxic basin to open ventilated ocean is accompanied by at least three geochemical and isotopic shifts and an increase in elements (e.g., K/Al) controlled by detrital minerals highlighting significant changes in sediment types and sources. The isotopic compositions of the sediments prior to ventilation are more variable but indicate a predominance of older crustal contributions consistent with sources from the Canadian Shield. Following ventilation, the isotopic compositions are more stable and indicate an increased contribution from younger material consistent with Eurasian and Pan-African crustal sources. The waxing and waning of these sources in conjunction with the passage of water through Fram Strait underlines the importance of the exchange of water mass between the Arctic and North Atlantic Oceans.

  7. Linkages between the circulation and distribution of dissolved organic matter in the White Sea, Arctic Ocean

    OpenAIRE

    Pavlov, Alexey K.; Stedmon, Colin A.; Semushin, Andrey V.; Martma, Tõnu; Ivanov, Boris V.; Kowalczuk, Piotr; Granskog, Mats A.

    2016-01-01

    The White Sea is a semi-enclosed Arctic marginal sea receiving a significant loading of freshwater (225-231 km3 yr-1 equaling an annual runoff yield of 2.5 m) and dissolved organic matter (DOM) from river run-off. We report discharge weighed values of stable oxygen isotope ratios (δ18O) of -14.0‰ in Northern Dvina river for the period 10 May-12 October 2012. We found a significant linear relationship between salinity (S) and δ18O (δ18O=-17.66±0.58+0.52±0.02×S; R2=0.96, N=162), which indicates...

  8. The air-sea equilibrium and time trend of hexachlorocyclohexanes in the Atlantic Ocean between the Arctic and Antarctica.

    Science.gov (United States)

    Lakaschus, Sonke; Weber, Kurt; Wania, Frank; Bruhn, Regina; Schrems, Otto

    2002-01-15

    Hexachlorocyclohexanes (HCHs) were determined simultaneously in air and seawater during two cruises across the Atlantic Ocean between the Arctic Ocean (Ny-Alesund/ Svalbard, 79 degrees N; 12 degrees E) and the Antarctic Continent (Neumayer Station/ Ekstroem Ice Shelf, 70 degrees S; 8.2 degrees W) in 1999/ 2000. The concentrations of alpha-HCH and gamma-HCH in air and surface waters of the Arctic exceeded those in Antarctica by 1-2 orders of magnitude. The gaseous concentrations of gamma-HCH were highest above the North Sea and between 20 degrees N and 30 degrees S. Fugacity fractions were used to estimate the direction of the air-sea gas exchange. These showed for alpha-HCH thatthe measured concentrations in both phases were close to equilibrium in the North Atlantic (78 degrees N-40 degrees N), slightly undersaturated between 30 degrees N and 10 degrees S and again close to equilibrium between 20 degrees S and 50 degrees S. Y-HCH has reached phase equilibrium in the North Atlantic as alpha-HCH, but the surface waters of the tropical and southern Atlantic were strongly undersaturated with y-HCH, especially between 30 degrees N and 20 degrees S. These findings are significantly different from two earlier estimates around 1990 as a result of global emission changes within the past decade. Therefore, we investigated the time trend of the HCHs in the surface waters of the Atlantic between 50 degrees N and 60 degrees S on the basis of archived samples taken in 1987-1997 and those from 1999. A decrease of alpha-HCH by a factor of approximately 4 is observed at all sampling locations. No decrease of gamma-HCH occurred between 30 degrees N and 30 degrees S, but there was a decrease in the North Atlantic, North Sea, and in the South Atlantic south of 40 degrees S. The constant level of gamma-HCH in the tropical Atlantic confirms the conclusion that the tropical Atlantic acts as a sink for y-HCH at present time. The measured alpha-HCH seawater concentrations were compared

  9. Organic molecular composition of marine aerosols over the Arctic Ocean in summer: contributions of primary emission and secondary aerosol formation

    Directory of Open Access Journals (Sweden)

    P. Q. Fu

    2013-02-01

    Full Text Available Organic molecular composition of marine aerosol samples collected during the MALINA cruise in the Arctic Ocean was investigated by gas chromatography/mass spectrometry. More than 110 individual organic compounds were determined in the samples and were grouped into different compound classes based on the functionality and sources. The concentrations of total quantified organics ranged from 7.3 to 185 ng m−3 (mean 47.6 ng m−3, accounting for 1.8–11.0% (4.8% of organic carbon in the marine aerosols. Primary saccharides were found to be dominant organic compound class, followed by secondary organic aerosol (SOA tracers formed from the oxidation of biogenic volatile organic compounds (VOCs such as isoprene, α-pinene and β-caryophyllene. Mannitol, the specific tracer for airborne fungal spores, was detected as the most abundant organic species in the samples with a concentration range of 0.052–53.3 ng m−3 (9.2 ng m−3, followed by glucose, arabitol, and the isoprene oxidation products of 2-methyltetrols. Biomass burning tracers such as levoglucosan are evident in all samples with trace levels. On the basis of the tracer-based method for the estimation of fungal-spore OC and biogenic secondary organic carbon (SOC, we estimate that an average of 10.7% (up to 26.2% of the OC in the marine aerosols was due to the contribution of fungal spores, followed by the contribution of isoprene SOC (mean 3.8% and α-pinene SOC (2.9%. In contrast, only 0.19% of the OC was due to the photooxidation of β-caryophyllene. This study indicates that primary organic aerosols from biogenic emissions, both from long-range transport of mid-latitude aerosols and from sea-to-air emission of marine organics, as well as secondary organic aerosols formed from the photooxidation of biogenic VOCs are important factors controlling the organic chemical composition of marine aerosols in the Arctic Ocean.

  10. Atmospheric HCH concentrations over the Marine Boundary Layer from Shanghai, China to the Arctic Ocean: role of human activity and climate change.

    Science.gov (United States)

    Wu, Xiaoguo; Lam, James C W; Xia, Chonghuan; Kang, Hui; Sun, Liguang; Xie, Zhouqing; Lam, Paul K S

    2010-11-15

    From July to September 2008, air samples were collected aboard the research expedition icebreaker XueLong (Snow Dragon) as part of the 2008 Chinese Arctic Research Expedition Program. Hexachlorocyclohexane (HCH) concentrations were analyzed in all of the samples. The average concentrations (± standard deviation) over the entire period were 33 ± 16, 5.4 ± 3.0, and 13 ± 7.5 pg m⁻³ for α-, β- and γ-HCH, respectively. Compared to previous studies in the same areas, total HCH (ΣHCH, the sum of α-, β-, and γ-HCH) levels declined by more than 10 × compared to those observed in the 1990s, but were approximately 4 × higher than those measured by the 2003 China Arctic Research Expedition, suggesting the increase of atmospheric ΣHCH recently. Because of the continuing use of lindane, ratios of α/γ-HCH showed an obvious decrease in North Pacific and Arctic region compared with those for 2003 Chinese Arctic Research Expedition. In Arctic, the level of α-HCH was found to be linked to sea ice distribution. Geographically, the average concentration of α-HCH in air samples from the Chukchi and Beaufort Seas, neither of which contain sea ice, was 23 ± 4.4 pg m⁻³, while samples from the area covered by seasonal ice (∼75°N to ∼83°N), the so-called "floating sea ice region", contained the highest average levels of α-HCH at 48 ± 12 pg m⁻³, likely due to emission from sea ice and strong air-sea exchange. The lowest concentrations of α-HCH were observed in the pack ice region in the high Arctic covered by multiyear sea ice (∼83°N to ∼86°N). This phenomenon implies that the re-emission of HCH trapped in ice sheets and Arctic Ocean may accelerate during the summer as ice coverage in the Arctic Ocean decreases in response to global climate change.

  11. Isotope composition and volume of Earth's early oceans.

    Science.gov (United States)

    Pope, Emily C; Bird, Dennis K; Rosing, Minik T

    2012-03-20

    Oxygen and hydrogen isotope compositions of Earth's seawater are controlled by volatile fluxes among mantle, lithospheric (oceanic and continental crust), and atmospheric reservoirs. Throughout geologic time the oxygen mass budget was likely conserved within these Earth system reservoirs, but hydrogen's was not, as it can escape to space. Isotopic properties of serpentine from the approximately 3.8 Ga Isua Supracrustal Belt in West Greenland are used to characterize hydrogen and oxygen isotope compositions of ancient seawater. Archaean oceans were depleted in deuterium [expressed as δD relative to Vienna standard mean ocean water (VSMOW)] by at most 25 ± 5‰, but oxygen isotope ratios were comparable to modern oceans. Mass balance of the global hydrogen budget constrains the contribution of continental growth and planetary hydrogen loss to the secular evolution of hydrogen isotope ratios in Earth's oceans. Our calculations predict that the oceans of early Earth were up to 26% more voluminous, and atmospheric CH(4) and CO(2) concentrations determined from limits on hydrogen escape to space are consistent with clement conditions on Archaean Earth.

  12. Long-Term Observations of Atmospheric CO2, O3 and BrO over the Transitioning Arctic Ocean Pack-ice: The O-Buoy Chemical Network

    Science.gov (United States)

    Matrai, P.

    2016-02-01

    Autonomous, sea ice-tethered O-Buoys have been deployed (2009-2016) across the Arctic sea ice for long-term atmospheric measurements (http://www.o-buoy.org). O-Buoys (15) provide in-situ concentrations of three sentinel atmospheric chemicals, ozone, CO2 and BrO, as well as meteorological parameters and imagery, over the frozen ocean. O-Buoys were designed to transmit daily data over a period of 2 years while deployed in sea ice, as part of automated ice-drifting stations that include snow/ice measurement systems (e.g. Ice Mass Balance buoys) and oceanographic measurements (e.g. Ice Tethered Profilers). Seasonal changes in Arctic atmospheric chemistry are influenced by changes in the characteristics and presence of the sea ice vs. open water as well as air mass trajectories, especially during the winter-spring and summer-fall transitions when sea ice is melting and freezing, respectively. The O-Buoy Chemical Network provides the unique opportunity to observe these transition periods in real-time with high temporal resolution, and to compare them with those collected on land-based monitoring stations located. Due to the logistical challenges of measurements over the Arctic Ocean region, most long term, in-situ observations of atmospheric chemistry have been made at coastal or island sites around the periphery of the Arctic Ocean, leaving large spatial and temporal gaps that O-Buoys overcome. Advances in floatation, communications, power management, and sensor hardware have been made to overcome the challenges of diminished Arctic sea ice. O-Buoy data provide insights into enhanced seasonal, interannual and spatial variability in atmospheric composition, atmospheric boundary layer control on the amount of halogen activation, enhancement of the atmospheric CO2 signal over the more variable and porous pack ice, and to develop an integrated picture of the coupled ocean/ice/atmosphere system. As part of the Arctic Observing Network, we provide data to the community (www.aoncadis.org).

  13. Linkages between the circulation and distribution of dissolved organic matter in the White Sea, Arctic Ocean

    Science.gov (United States)

    Pavlov, Alexey K.; Stedmon, Colin A.; Semushin, Andrey V.; Martma, Tõnu; Ivanov, Boris V.; Kowalczuk, Piotr; Granskog, Mats A.

    2016-05-01

    The White Sea is a semi-enclosed Arctic marginal sea receiving a significant loading of freshwater (225-231 km3 yr-1 equaling an annual runoff yield of 2.5 m) and dissolved organic matter (DOM) from river run-off. We report discharge weighed values of stable oxygen isotope ratios (δ18O) of -14.0‰ in Northern Dvina river for the period 10 May-12 October 2012. We found a significant linear relationship between salinity (S) and δ18O (δ18O=-17.66±0.58+0.52±0.02×S; R2=0.96, N=162), which indicates a dominant contribution of river water to the freshwater budget and little influence of sea ice formation or melt. No apparent brine additions from sea-ice formation is evident in the White Sea deep waters as seen from a joint analysis of temperature (T), S, δ18O and aCDOM(350) data, confirming previous suggestions about strong tidal induced vertical mixing in winter being the likely source of the deep waters. We investigated properties and distribution of colored dissolved organic matter (CDOM) and dissolved organic carbon (DOC) in the White Sea basin and coastal areas in summer. We found contrasting DOM properties in the inflowing Barents Sea waters and White Sea waters influenced by terrestrial runoff. Values of absorption by CDOM at 350 nm (aCDOM(350)) and DOC (exceeding 10 m-1 and 550 μmol l-1, respectively) in surface waters of the White Sea basin are higher compared to other river-influenced coastal Arctic domains. Linear relationship between S and CDOM absorption, and S and DOC (DOC=959.21±52.99-25.80±1.79×S; R2=0.85; N=154) concentrations suggests conservative mixing of DOM in the White Sea. The strongest linear correlation between CDOM absorption and DOC was found in the ultraviolet (DOC=56.31±2.76+9.13±0.15×aCDOM(254); R2=0.99; N=155), which provides an easy and robust tool to trace DOC using CDOM absorption measurements as well as remote sensing algorithms. Deviations from this linear relationship in surface waters likely indicate contribution from

  14. Links between ocean properties, ice cover, and plankton dynamics on interannual time scales in the Canadian Arctic Archipelago

    Science.gov (United States)

    Hamilton, James M.; Collins, Kate; Prinsenberg, Simon J.

    2013-10-01

    A decade of instrumented mooring data from Barrow Strait in the eastern Canadian Arctic Archipelago reveals connections between sea ice, water characteristics, and zooplankton dynamics on interannual time scales. On the North side of the Strait, the timing of breakup is positively related to the timing of freezeup in the previous year and negatively related to spring water temperature. This suggests that an early freezeup insulates the ocean from a cold autumn atmosphere, allowing heat to be retained until spring when it contributes to early sea ice erosion. There is also a very strong negative association between the timing of freezeup and late summer salinity, suggesting that monitoring of salinity in real time could be used to predict freezeup. A zooplankton biomass index derived from acoustic Doppler current profiler echo intensity data is used to demonstrate that on the North side there are also strong connections between early summer water temperature and the start, length, and productivity of the zooplankton growth season. On the South side of the Strait where currents are stronger, the relationships seen on the North side were not observed. But here integrated zooplankton biomass index and measured currents are used to identify interannual variability in the zooplankton biomass being delivered downstream into Lancaster Sound. Also on the South side, two yearlong records of daily fluorescence profiles reveal a large difference in the phytoplankton biomass being delivered downstream between years and demonstrate a strong relationship between the timing of the spring phytoplankton bloom and that of breakup.

  15. Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane.

    Science.gov (United States)

    Pohlman, John W; Greinert, Jens; Ruppel, Carolyn; Silyakova, Anna; Vielstädte, Lisa; Casso, Michael; Mienert, Jürgen; Bünz, Stefan

    2017-05-23

    Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 10 6 tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (shallow ebullitive methane seep field on the Svalbard margin reveal atmospheric CO 2 uptake rates (-33,300 ± 7,900 μmol m -2 ⋅d -1 ) twice that of surrounding waters and ∼1,900 times greater than the diffusive sea-air methane efflux (17.3 ± 4.8 μmol m -2 ⋅d -1 ). The negative radiative forcing expected from this CO 2 uptake is up to 231 times greater than the positive radiative forcing from the methane emissions. Surface water characteristics (e.g., high dissolved oxygen, high pH, and enrichment of 13 C in CO 2 ) indicate that upwelling of cold, nutrient-rich water from near the seafloor accompanies methane emissions and stimulates CO 2 consumption by photosynthesizing phytoplankton. These findings challenge the widely held perception that areas characterized by shallow-water methane seeps and/or strongly elevated sea-air methane flux always increase the global atmospheric greenhouse gas burden.

  16. Composition and fate of terrigenous organic matter along the Arctic land-ocean continuum in East Siberia: Insights from biomarkers and carbon isotopes

    Science.gov (United States)

    Tesi, Tommaso; Semiletov, Igor; Hugelius, Gustaf; Dudarev, Oleg; Kuhry, Peter; Gustafsson, Örjan

    2014-05-01

    Climate warming is predicted to translocate terrigenous organic carbon (TerrOC) to the Arctic Ocean and affect the marine biogeochemistry at high latitudes. The magnitude of this translocation is currently unknown, so is the climate response. The fate of the remobilized TerrOC across the Arctic shelves represents an unconstrained component of this feedback. The present study investigated the fate of permafrost carbon along the land-ocean continuum by characterizing the TerrOC composition in three different terrestrial carbon pools from Siberian permafrost (surface organic rich horizon, mineral soil active layer, and Ice Complex deposit) and marine sediments collected on the extensive East Siberian Arctic Shelf (ESAS). High levels of lignin phenols and cutin acids were measured in all terrestrial samples analyzed indicating that these compounds can be used to trace the heterogeneous terrigenous material entering the Arctic Ocean. In ESAS sediments, comparison of these terrigenous biomarkers with other TerrOC proxies (bulk δ13C/Δ14C and HMW lipid biomarkers) highlighted contrasting across-shelf trends. These differences could indicate that TerrOC in the ESAS is made up of several pools that exhibit contrasting reactivity toward oxidation during the transport. In this reactive spectrum, lignin is the most reactive, decreasing up to three orders of magnitude from the inner- to the outer-shelf while the decrease of HMW wax lipid biomarkers was considerably less pronounced. Alternatively, degradation might be negligible while sediment sorting during the across-shelf transport could be the major physical forcing that redistributes different TerrOC pools characterized by different matrix-association.

  17. The measurement of I-129 in the Canadian Arctic basin and other Arctic waters

    International Nuclear Information System (INIS)

    Kilius, L.R.; Zhao, X.L.

    1995-01-01

    Since the first demonstration by accelerator mass spectrometry for the measurement of 129 I in oceanic systems, the use of 129 I as a long range tracer has become widespread because the constraint of large sample volumes has been removed. Following extensive measurements of 129 I in both the Barents and Kara Seas, seawater samples were collected within the Canadian Arctic Basin, and at a cruise from the Chuchi Sea, across the pole, to the Norwegian Sea. Only 450 ml samples were required for all AMS measurements of Arctic seawater. Enhanced concentrations of 129 I were observed. Based on 137 Cs measurements for the same samples, the 129 I/ 137 Cs ratios showed the signature of Sellafield reprocessing effluents as the primary source of this 129 I. Based on average estimates, 13% of the total Sellafield/La Hague 129 I emissions now resides within the Atlantic layer of the Arctic Ocean. 7 refs., 3 figs

  18. Arctic circulation regimes.

    Science.gov (United States)

    Proshutinsky, Andrey; Dukhovskoy, Dmitry; Timmermans, Mary-Louise; Krishfield, Richard; Bamber, Jonathan L

    2015-10-13

    Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals. During cyclonic regimes, low sea-level atmospheric pressure (SLP) dominated over the Arctic Ocean driving sea ice and the upper ocean counterclockwise; the Arctic atmosphere was relatively warm and humid, and freshwater flux from the Arctic Ocean towards the subarctic seas was intensified. By contrast, during anticylonic circulation regimes, high SLP dominated driving sea ice and the upper ocean clockwise. Meanwhile, the atmosphere was cold and dry and the freshwater flux from the Arctic to the subarctic seas was reduced. Since 1997, however, the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime. We discuss a hypothesis explaining the causes and mechanisms regulating the intensity and duration of Arctic circulation regimes, and speculate how changes in freshwater fluxes from the Arctic Ocean and Greenland impact environmental conditions and interrupt their decadal variability. © 2015 The Authors.

  19. Integrating surface and mantle constraints for palaeo-ocean evolution: a tour of the Arctic and adjacent regions (Arne Richter Award for Outstanding Young Scientists Lecture)

    Science.gov (United States)

    Shephard, Grace E.

    2016-04-01

    Plate tectonic reconstructions heavily rely on absolute motions derived from hotspot trails or palaeomagnetic data and ocean-floor magnetic anomaies and fracture-zone geometries to constrain the detailed history of ocean basins. However, as oceanic lithosphere is progressively recycled into the mantle, kinematic data regarding the history of these now extinct-oceans is lost. In order to better understand their evolution, novel workflows, which integrate a wide range of complementary yet independent geological and geophysical datasets from both the surface and deep mantle, must be utilised. In particular, the emergence of time-dependent, semi or self-consistent geodynamic models of ever-increasing temporal and spatial resolution are revealing some critical constraints on the evolution and fate of oceanic slabs. The tectonic evolution of the circum-Arctic is no exception; since the breakup of Pangea, this enigmatic region has seen major plate reorganizations and the opening and closure of several ocean basins. At the surface, a myriad of potential kinematic scenarios including polarity, timing, geometry and location of subduction have emerged, including for systems along continental margins and intra-oceanic settings. Furthermore, recent work has reignited a debate about the origins of 'anchor' slabs, such as the Farallon and Mongol-Okhotsk slabs, which have been used to refine absolute plate motions. Moving to the mantle, seismic tomography models reveal a region peppered with inferred slabs, however assumptions about their affinities and subduction location, timing, geometry and polarity are often made in isolation. Here, by integrating regional plate reconstructions with insights from seismic tomography, satellite derived gravity gradients, slab sinking rates and geochemistry, I explore some Mesozoic examples from the palaeo-Arctic, northern Panthalassa and western margin of North America, including evidence for a discrete and previously undescribed slab under

  20. The Coastal Ocean Prediction Systems program: Understanding and managing our coastal ocean. Volume 1: Strategic summary

    Energy Technology Data Exchange (ETDEWEB)

    1990-05-15

    The proposed COPS (Coastal Ocean Prediction Systems) program is concerned with combining numerical models with observations (through data assimilation) to improve our predictive knowledge of the coastal ocean. It is oriented toward applied research and development and depends upon the continued pursuit of basic research in programs like COOP (Coastal Ocean Processes); i.e., to a significant degree it is involved with ``technology transfer`` from basic knowledge to operational and management applications. This predictive knowledge is intended to address a variety of societal problems: (1) ship routing, (2) trajectories for search and rescue operations, (3) oil spill trajectory simulations, (4) pollution assessments, (5) fisheries management guidance, (6) simulation of the coastal ocean`s response to climate variability, (7) calculation of sediment transport, (8) calculation of forces on structures, and so forth. The initial concern is with physical models and observations in order to provide a capability for the estimation of physical forces and transports in the coastal ocean. For all these applications, there are common needs for physical field estimates: waves, tides, currents, temperature, and salinity, including mixed layers, thermoclines, fronts, jets, etc. However, the intent is to work with biologists, chemists, and geologists in developing integrated multidisciplinary prediction systems as it becomes feasible to do so. From another perspective, by combining observations with models through data assimilation, a modern approach to monitoring is provided through whole-field estimation.

  1. In-situ Measured Carbon and Nitrogen Uptake Rates of Melt Pond Algae in the Western Arctic Ocean, 2014

    Science.gov (United States)

    Song, Ho Jung; Kim, Kwanwoo; Lee, Jae Hyung; Ahn, So Hyun; Joo, Houng-Min; Jeong, Jin Young; Yang, Eun Jin; Kang, Sung-Ho; Yun, Mi Sun; Lee, Sang Heon

    2018-03-01

    Although the areal coverage of melt pond in the Arctic Ocean has recently increased, very few biological researches have been conducted. The objectives in this study were to ascertain the uptake rates of carbon and nitrogen in various melt ponds and to understand the major controlling factors for the rates. We obtained 22 melt pond samples at ice camp 1 (146.17°W, 77.38°N) and 11 melt pond samples at ice camp 2 (169.79°W, 76.52°N). The major nutrient concentrations varied largely among melt ponds at the ice camps 1 and 2. The chl-a concentrations averaged from the melt ponds at camps 1 and 2 were 0.02-0.56 mg chl-a m-3 (0.12 ± 0.12 mg chl-a m-3) and 0.08-0.30 mg chl-a m-3 (0.16 ± 0.08 mg chl-a m-3), respectively. The hourly carbon uptake rates at camps 1 and 2 were 0.001-0.080 mg C m-3 h-1 (0.025 ± 0.024 mg C m-3 h-1) and 0.022-0.210 mg C m-3 h-1 (0.077 ± 0.006 mg C m-3 h-1), respectively. In comparison, the nitrogen uptake rates at camps 1 and 2 were 0.001-0.030 mg N m-3 h-1 (0.011 ± 0.010 mg N m-3 h-1) and 0.002-0.022 mg N m-3 h-1 (0.010 ± 0.006 mg N m-3 h-1), respectively. The values obtained in this study are significantly lower than those reported previously. A large portion of algal biomass trapped in the new forming surface ice in melt ponds appears to be one of the main potential reasons for the lower chl-a concentration and subsequently lower carbon and nitrogen uptake rates revealed in this study. A long-term monitoring program on melt ponds is needed to understand the response of the Arctic marine ecosystem to ongoing environmental changes.

  2. Towards improved estimation of the dynamic topography and ocean circulation in the high latitude and arctic ocean: The importance of GOCE

    DEFF Research Database (Denmark)

    Johannessen, J. A.; Raj, R. P.; Nilsen, J. E. Ø.

    2013-01-01

    The Arctic plays a fundamental role in the climate system and shows significant sensitivity to anthropogenic climate forcing and the ongoing climate change. Evidently changes in the Arctic and surrounding seas have far reaching influences on regional and global environment and climate variability...

  3. Volume Transport Stream Function Calculated from World Ocean Atlas 2013 (WOA13-VTSF) and Climatological Wind (NCEI Accession 0138646)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset consists of calculated annual and monthly mean ocean volume transport stream function on 1 degree resolution using the WOA13 (T, S) and corresponding...

  4. Arctic Freshwater Switchyard Project: Spring temperature and Salinity data collected by aircraft in the Arctic Ocean, May 2006 - May 2007 (NODC Accession 0057319)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A program to study freshwater circulation (sea ice + upper ocean) in the "freshwater switchyard" between Alert (Ellesmere Island) and the North Pole. The project...

  5. Experiences in multiyear combined state-parameter estimation with an ecosystem model of the North Atlantic and Arctic Oceans using the Ensemble Kalman Filter

    Science.gov (United States)

    Simon, Ehouarn; Samuelsen, Annette; Bertino, Laurent; Mouysset, Sandrine

    2015-12-01

    A sequence of one-year combined state-parameter estimation experiments has been conducted in a North Atlantic and Arctic Ocean configuration of the coupled physical-biogeochemical model HYCOM-NORWECOM over the period 2007-2010. The aim is to evaluate the ability of an ensemble-based data assimilation method to calibrate ecosystem model parameters in a pre-operational setting, namely the production of the MyOcean pilot reanalysis of the Arctic biology. For that purpose, four biological parameters (two phyto- and two zooplankton mortality rates) are estimated by assimilating weekly data such as, satellite-derived Sea Surface Temperature, along-track Sea Level Anomalies, ice concentrations and chlorophyll-a concentrations with an Ensemble Kalman Filter. The set of optimized parameters locally exhibits seasonal variations suggesting that time-dependent parameters should be used in ocean ecosystem models. A clustering analysis of the optimized parameters is performed in order to identify consistent ecosystem regions. In the north part of the domain, where the ecosystem model is the most reliable, most of them can be associated with Longhurst provinces and new provinces emerge in the Arctic Ocean. However, the clusters do not coincide anymore with the Longhurst provinces in the Tropics due to large model errors. Regarding the ecosystem state variables, the assimilation of satellite-derived chlorophyll concentration leads to significant reduction of the RMS errors in the observed variables during the first year, i.e. 2008, compared to a free run simulation. However, local filter divergences of the parameter component occur in 2009 and result in an increase in the RMS error at the time of the spring bloom.

  6. Evolution of Summer Ocean Mixed Layer Heat Content and Ocean/Ice Fluxes in the Arctic Ocean During the Last Decade

    Science.gov (United States)

    Stanton, T. P.; Shaw, W. J.

    2014-12-01

    Since 2002, a series of 28 Autonomous Ocean Flux Buoys have been deployed in the Beaufort Sea and from the North Pole Environmental Observatory. These long-term ice-deployed instrument systems primarily measure vertical turbulent fluxes of heat, salt and momentum at a depth of 2 - 6 m below the ocean/ice interface, while concurrently measuring current profile every 2m down to approximately 40-50m depth, within the seasonal pycnocline. Additional sensors have been added to measure local ice melt rates acoustically, and finescale thermal structure from the eddy correlation flux sensor up into the ice to resolve summer near-surface heating. The AOFB buoys have typically been co-located with Ice Tethered Profilers, that measure the upper ocean T/S structure and ice mass balance instruments. Comparisons of near-surface heat fluxes, heat content and vertical structure over the last decade will be made for buoys in the Beaufort Sea and Transpolar Drift between the North Pole and Spitzbergen. The effects of enhanced basal melting from ice/albedo feedbacks can be clearly seen in the low ice concentration summer conditions found more recently in the Beaufort Sea, while there are less pronounced effects of enhanced summer surface heating in the higher ice concentrations still found in the transpolar drift.

  7. Crustal volumes of the continents and of oceanic and continental submarine plateaus

    Science.gov (United States)

    Schubert, G.; Sandwell, D.

    1989-01-01

    Using global topographic data and the assumption of Airy isostasy, it is estimated that the crustal volume of the continents is 7182 X 10 to the 6th cu km. The crustal volumes of the oceanic and continental submarine plateaus are calculated at 369 X 10 to the 6th cu km and 242 X 10 to the 6th cu km, respectively. The total continental crustal volume is found to be 7581 X 10 to the 6th cu km, 3.2 percent of which is comprised of continental submarine plateaus on the seafloor. An upper bound on the contintental crust addition rate by the accretion of oceanic plateaus is set at 3.7 cu km/yr. Subduction of continental submarine plateaus with the oceanic lithosphere on a 100 Myr time scale yields an upper bound to the continental crustal subtraction rate of 2.4 cu km/yr.

  8. Putting Science First: Using the Precautionary Principle in the Central Arctic Ocean to Prevent a Fishing Disaster Before it Occurs (Invited)

    Science.gov (United States)

    Nachman, C.

    2017-12-01

    As ice conditions change and ocean temperatures continue to rise, the potential for living marine resources to migrate farther north and for vessels to journey north with them is expanding. To date, the central Arctic Ocean (CAO) has remained relatively unexposed to human activities, including commercial fishing. However, as conditions continue to change, the potential for expansion of fishing fleets exists. In July 2015, the five Arctic coastal states signed a declaration concerning the prevention of unregulated high seas fishing in the CAO. Recognizing the need to involve additional nations with interests in the Arctic region, in December 2015, the five Arctic coastal states, along with China, the European Union, Japan, Iceland, and Korea, began a process to negotiate a binding agreement to prevent unregulated fishing in the high seas of the CAO. A key underlying goal of the negotiations is to reach agreement that nations would establish a joint program of scientific research and monitoring to better understand the CAO ecosystem and whether fish stocks might exist there that could be harvested on a sustainable basis and the possible impacts of such fisheries on the ecosystems. The data collected through the international joint science program will compose a key piece of the decision-making at the policy level regarding establishing appropriate measures or organizations to manage fishing in the CAO should the science indicate potentials for commercial fishing in the CAO. Since the beginning of these high-level negotiations, the policy makers have consistently agreed that conducting collaborative science is the primary way to determine whether sustainable commercial fishing could one day occur in the region. I will highlight the policy negotiation process and parallel science meetings to date to demonstrate how science can influence policy to prevent a fishing disaster.

  9. Collaborative Project. Understanding the effects of tides and eddies on the ocean dynamics, sea ice cover and decadal/centennial climate prediction using the Regional Arctic Climate Model (RACM)

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, Jennifer [Univ. of Alaska, Fairbanks, AK (United States); Joseph, Renu [Univ. of Alaska, Fairbanks, AK (United States)

    2013-09-14

    The goal of this project is to develop an eddy resolving ocean model (POP) with tides coupled to a sea ice model (CICE) within the Regional Arctic System Model (RASM) to investigate the importance of ocean tides and mesoscale eddies in arctic climate simulations and quantify biases associated with these processes and how their relative contribution may improve decadal to centennial arctic climate predictions. Ocean, sea ice and coupled arctic climate response to these small scale processes will be evaluated with regard to their influence on mass, momentum and property exchange between oceans, shelf-basin, ice-ocean, and ocean-atmosphere. The project will facilitate the future routine inclusion of polar tides and eddies in Earth System Models when computing power allows. As such, the proposed research addresses the science in support of the BER’s Climate and Environmental Sciences Division Long Term Measure as it will improve the ocean and sea ice model components as well as the fully coupled RASM and Community Earth System Model (CESM) and it will make them more accurate and computationally efficient.

  10. Quantitative and phylogenetic study of the Deep Sea Archaeal Group in sediments of the arctic mid-ocean spreading ridge

    Directory of Open Access Journals (Sweden)

    Steffen Leth eJørgensen

    2013-10-01

    Full Text Available In marine sediments archaea often constitute a considerable part of the microbial community, of which the Deep Sea Archaeal Group (DSAG is one of the most predominant. Despite their high abundance no members from this archaeal group have so far been characterized and thus their metabolism is unknown. Here we show that the relative abundance of DSAG marker genes can be correlated with geochemical parameters, allowing prediction of both the potential electron donors and acceptors of these organisms. We estimated the abundance of 16S rRNA genes from Archaea, Bacteria and DSAG in 52 sediment horizons from two cores collected at the slow-spreading Arctic Mid-Ocean Ridge, using qPCR. The results indicate that members of the DSAG make up the entire archaeal population in certain horizons and constitute up to ~ 50% of the total microbial community. The quantitative data were correlated to 30 different geophysical and geochemical parameters obtained from the same sediment horizons. We observed a significant correlation between the relative abundance of DSAG 16S rRNA genes and the content of organic carbon (p < 0.0001. Further, significant co-variation with iron oxide, and dissolved iron and manganese (all p < 0.0000, indicated a direct or indirect link to iron and manganese cycling. Neither of these parameters correlated with the relative abundance of archaeal or bacterial 16S rRNA genes, nor did any other major electron donor or acceptor measured. Phylogenetic analysis of DSAG 16S rRNA gene sequences reveals three monophyletic lineages with no apparent habitat-specific distribution. In this study we support the hypothesis that members of the DSAG are tightly linked to the content of organic carbon and directly or indirectly involved in the cycling of iron and/or manganese compounds. Further, we provide a molecular tool to assess their abundance in environmental samples and enrichment cultures.

  11. Remote sensing for global change, climate change and atmosphere and ocean forecasting. Volume 1

    International Nuclear Information System (INIS)

    1992-01-01

    This volume is separated in three sessions. First part is on remote sensing for global change (with global modelling, land cover change on global scale, ocean colour studies of marine biosphere, biological and hydrological interactions and large scale experiments). Second part is on remote sensing for climate change (with earth radiation and clouds, sea ice, global climate research programme). Third part is on remote sensing for atmosphere and ocean forecasting (with temperatures and humidity, winds, data assimilation, cloud imagery, sea surface temperature, ocean waves and topography). (A.B.). refs., figs., tabs

  12. Arctic carbon cycling

    NARCIS (Netherlands)

    Christensen, Torben R; Rysgaard, SØREN; Bendtsen, JØRGEN; Else, Brent; Glud, Ronnie N; van Huissteden, J.; Parmentier, F.J.W.; Sachs, Torsten; Vonk, J.E.

    2017-01-01

    The marine Arctic is considered a net carbon sink, with large regional differences in uptake rates. More regional modelling and observational studies are required to reduce the uncertainty among current estimates. Robust projections for how the Arctic Ocean carbon sink may evolve in the future are

  13. New deglacial and Holocene micropaleontological and geochemical records from the southern margin of the Svalbard Archipelago (Arctic Ocean)

    Science.gov (United States)

    Rigual-Hernández, Andrés.

    2010-05-01

    This study is presented in the context of the Spanish research project "The development of an Arctic ice stream-dominated sedimentary system: The southern Svalbard continental margin" (SVAIS), developed within the framework of the International Polar Year (IPY) Activity N. 367 (NICE STREAMS). Its main goal is to understand the evolution of glacial continental margins and their relationship with the changes in ice sheet dynamics induced by natural climatic changes, combining the geophysical data with the sediment record both collected during an oceanographic cruise in the Storfjorden area (SW Svalbard margin) in August 2007. This marine depositional system, dominated by an ice stream during the last glacial period, was selected due to its small size inducing a rapid response to climatic changes, and for the oceanographic relevance of the area for global ocean circulation. The results obtained aim to define the sedimentary architecture and morphology, and to provide more insight into the paleoceanographic and paleoclimatic evolution of the region. We specifically report on new micropaleontological and geochemical data obtained from the sediment cores. A preliminary age model indicates that the sediment sequences cover approximately the Last Deglaciation and the Holocene. Microfossils are generally well preserved, although the abundances of the different groups show marked shifts along the record. Low concentrations of coccolithophores, diatoms, planktic foraminifers and cysts of organic-walled dinoflagellates (dinocysts) are found at the lower half of the sequence (IRD-rich, coarser-grained sediments), and increase towards the Late Holocene (fine-grained bioturbated sediments). The Climatic Optimum is characterized by the warmest sea surface temperatures as estimated from the fossil assemblage, diverse transfer functions and biogeochemical proxies, and by high nutrient contents in the bottom waters shown by light carbon isotope values and high Cd/Ca ratios in benthic

  14. 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 ODEN in the Arctic Ocean, Beaufort Sea and Bering Sea from 2005-08-19 to 2005-09-25 (NODC Accession 0108129)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108129 includes chemical, discrete sample, physical and profile data collected from ODEN in the Arctic Ocean, Beaufort Sea and Bering Sea from...

  15. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Barometric pressure sensor, Carbon dioxide (CO2) gas analyzer and other instruments from the JAMES CLARK ROSS in the Arctic Ocean, Barents Sea and others from 2012-11-15 to 2013-08-16 (NODC Accession 0115256)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115256 includes chemical, meteorological, physical and underway - surface data collected from JAMES CLARK ROSS in the Arctic Ocean, Barents Sea,...

  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 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 — NCEI Accession 0113952 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and...

  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 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 — NCEI Accession 0115592 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and...

  18. 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...

  19. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from 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 — NCEI Accession 0115707 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and...

  20. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JAN MAYEN in the Arctic Ocean and Barents Sea from 2004-07-24 to 2004-07-31 (NODC Accession 0113566)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113566 includes chemical, discrete sample, physical and profile data collected from JAN MAYEN in the Arctic Ocean and Barents Sea from 2004-07-24 to...

  1. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from 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 — NCEI Accession 0113953 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  2. 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...

  3. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LOUIS S. ST. LAURENT in the Arctic Ocean and Beaufort Sea from 1997-09-24 to 1997-10-15 (NODC Accession 0113984)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113984 includes chemical, discrete sample, physical and profile data collected from LOUIS S. ST. LAURENT in the Arctic Ocean and Beaufort Sea from...

  4. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LOUIS S. ST. LAURENT in the Arctic Ocean, Beaufort Sea and North Greenland Sea from 1994-07-24 to 1994-09-01 (NODC Accession 0113983)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113983 includes chemical, discrete sample, physical and profile data collected from LOUIS S. ST. LAURENT in the Arctic Ocean, Beaufort Sea and North...

  5. PH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from POLARSTERN in the Arctic Ocean, Kara Sea and Laptev Sea from 1995-07-07 to 1995-09-20 (NODC Accession 0116408)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0116408 includes chemical, discrete sample, physical and profile data collected from POLARSTERN in the Arctic Ocean, Kara Sea and Laptev (or...

  6. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the TYRO in the Arctic Ocean and Beaufort Sea from 1996-09-13 to 1996-10-28 (NODC Accession 0116717)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116717 includes chemical, discrete sample, physical and profile data collected from TYRO in the Arctic Ocean and Beaufort Sea from 1996-09-13 to...

  7. 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 and Beaufort Sea from 1999-09-11 to 1999-10-05 (NODC Accession 0112350)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112350 includes chemical, discrete sample, physical and profile data collected from MIRAI in the Arctic Ocean and Beaufort Sea from 1999-09-11 to...

  8. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JAN MAYEN in the Arctic Ocean, Barents Sea and North Greenland Sea from 2005-05-20 to 2005-06-02 (NODC Accession 0113564)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113564 includes chemical, discrete sample, physical and profile data collected from JAN MAYEN in the Arctic Ocean, Barents Sea and North Greenland...

  9. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the POLARSTERN in the Arctic Ocean, Barents Sea and Laptev (or Nordenskjold) Sea from 2007-07-28 to 2007-10-10 (NODC Accession 0109899)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0109899 includes chemical, discrete sample, physical and profile data collected from POLARSTERN in the Arctic Ocean, Barents Sea and Laptev (or...

  10. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from POLARSTERN in the Arctic Ocean, Barents Sea and others from 2011-06-17 to 2012-01-04 (NCEI Accession 0157242)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157242 includes Surface underway, chemical, meteorological and physical data collected from POLARSTERN in the Arctic Ocean, Barents Sea, Kara Sea,...

  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. Alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from MIRAI in the Arctic Ocean and Beaufort Sea from 2004-09-01 to 2004-10-13 (NODC Accession 0112357)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0112357 includes biological, chemical, discrete sample, physical and profile data collected from MIRAI in the Arctic Ocean and Beaufort Sea from...

  13. 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...

  14. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from 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...

  15. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2015-08-09 to 2015-10-12 (NCEI Accession 0157049)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157049 includes Surface underway, chemical, meteorological and physical data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea,...

  16. 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,...

  17. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from 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...

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

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

  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 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...

  1. 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 NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea and others from 2003-01-05 to 2004-01-15 (NCEI Accession 0157387)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157387 includes Surface underway, chemical, meteorological and physical data collected from NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea,...

  2. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Sikuliaq in the Arctic Ocean, Beaufort Sea and Bering Sea from 2015-08-13 to 2015-09-02 (NCEI Accession 0157261)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157261 includes Surface underway, chemical, meteorological and physical data collected from Sikuliaq in the Arctic Ocean, Beaufort Sea and Bering Sea...

  3. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from ODEN in the Arctic Ocean from 1991-07-26 to 1991-09-03 (NODC Accession 0113591)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0113591 includes chemical, discrete sample, physical and profile data collected from ODEN in the Arctic Ocean from 1991-07-26 to 1991-09-03. These...

  4. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the YMER in the Arctic Ocean, Barents Sea and North Greenland Sea from 1980-08-11 to 1980-09-19 (NODC Accession 0113607)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113607 includes chemical, discrete sample, physical and profile data collected from YMER in the Arctic Ocean, Barents Sea and North Greenland Sea...

  5. Dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the POLARSTERN in the Arctic Ocean and North Greenland Sea from 1987-07-04 to 1987-09-02 (NODC Accession 0113916)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113916 includes chemical, discrete sample, physical and profile data collected from POLARSTERN in the Arctic Ocean and North Greenland Sea from...

  6. 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...

  7. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from NOAA Ship RONALD H. BROWN in the Arctic Ocean, Beaufort Sea and others from 2015-01-15 to 2015-12-18 (NCEI Accession 0157252)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157252 includes Surface underway, chemical, meteorological and physical data collected from NOAA Ship RONALD H. BROWN in the Arctic Ocean, Beaufort...

  8. 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...

  9. Dissolved inorganic carbon, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the POLARSTERN in the Arctic Ocean, Kara Sea and Laptev (or Nordenskjold) Sea from 1993-08-06 to 1993-10-05 (NODC Accession 0113593)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113593 includes chemical, discrete sample, physical and profile data collected from POLARSTERN in the Arctic Ocean, Kara Sea and Laptev (or...

  10. Partial pressure (or fugacity) of carbon dioxide and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from POLARSTERN in the Arctic Ocean, Barents Sea and others from 2015-05-19 to 2015-12-01 (NCEI Accession 0160491)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0160491 includes Surface underway, chemical and meteorological data collected from POLARSTERN in the Arctic Ocean, Barents Sea, Bay of Biscay, English...

  11. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from POLARSTERN in the Arctic Ocean, Barents Sea and others from 2012-01-08 to 2012-10-06 (NCEI Accession 0157350)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157350 includes Surface underway, chemical, meteorological and physical data collected from POLARSTERN in the Arctic Ocean, Barents Sea, English...

  12. 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...

  13. Characteristics of colored dissolved organic matter (CDOM) in the Arctic outflow in Fram Strait: assessing the changes and fate of terrigenous CDOM in the Arctic Ocean

    DEFF Research Database (Denmark)

    Granskog, M.A.; Stedmon, Colin; Dodd, P.A.

    2012-01-01

    Absorption coefficients of colored dissolved organic matter (CDOM) were measured together with salinity, δ18O, and inorganic nutrients across the Fram Strait. A pronounced CDOM absorption maximum between 30 and 120 m depth was associated with river and sea ice brine enriched water, characteristic...... of the Arctic mixed layer and upper halocline waters in the East Greenland Current (EGC). The lowest CDOM concentrations were found in the Atlantic inflow. We show that the salinity-CDOM relationship is not suitable for evaluating conservative mixing of CDOM. The strong correlation between meteoric water...... and CDOM is indicative of the riverine/terrigenous origin of CDOM in the EGC. Based on CDOM absorption in Polar Water and comparison with an Arctic river discharge weighted mean, we estimate that a 49–59% integrated loss of CDOM absorption across 250–600 nm has occurred. A preferential removal...

  14. On a grain of sand - a microhabitat for the opportunistic agglutinated foraminifera Hemisphaerammina apta n. sp., from the early Eocene Arctic Ocean

    Science.gov (United States)

    McNeil, David H.; Neville, Lisa A.

    2018-02-01

    Hemisphaerammina apta n. sp. is an attached monothalamous agglutinated foraminifera discovered in shelf sediments of the early Eocene Arctic Ocean. It is a simple yet distinctive component of the endemic agglutinated foraminiferal assemblage that colonized the Arctic Ocean after the microfaunal turnover caused by the Paleocene-Eocene Thermal Maximum. Associated foraminifera are characterized by a high percentage of monothalamous species (up to 60 %) and are entirely agglutinated indicating a brackish (mesohaline) early Eocene Arctic Ocean. Hemisphaerammina apta occurs exclusively as individuals attached to fine detrital grains (0.2 to 1.8 mm) of sediment. It is a small species (0.06 to 0.2 mm in diameter), fine-grained, with a low hemispherical profile, no floor across the attachment area, no substantive marginal flange, no internal structures, and no aperture. Lacking an aperture, it apparently propagated and fed through minute (micrometre-sized) interstitial pores in the test wall. Attachment surfaces vary from concave to convex and rough to smooth. Grains for attachment are diverse in shape and type but are predominantly of quartz and chert. The presence of H. apta in the early Eocene was an opportunistic response to an environment with an active hydrological system (storm events). Attachment to grains of sand would provide a more stable base on a sea floor winnowed by storm-generated currents. Active transport is indicated by the relative abundance of reworked foraminifera mixed with in situ species. Contemporaneous reworking and colonization by H. apta is suggested by its attachment to a reworked specimen of Cretaceous foraminifera.

  15. Characteristics of colored dissolved organic matter (CDOM) in the Arctic outflow in the Fram Strait: Assessing the changes and fate of terrigenous CDOM in the Arctic Ocean

    OpenAIRE

    Granskog, M.A.; Stedmon, C.A.; Dodd, P.A.; Amon, R.M.W.; Pavlov, A.K.; de Steur, L.; Hansen, E.

    2012-01-01

    Absorption coefficients of colored dissolved organic matter (CDOM) were measured together with salinity, delta O-18, and inorganic nutrients across the Fram Strait. A pronounced CDOM absorption maximum between 30 and 120 m depth was associated with river and sea ice brine enriched water, characteristic of the Arctic mixed layer and upper halocline waters in the East Greenland Current (EGC). The lowest CDOM concentrations were found in the Atlantic inflow. We show that the salinity-CDOM relati...

  16. Ship-based Observations of Atmospheric Black Carbon Particles over the Arctic Ocean, Bering Sea, and North Western Pacific Ocean on 2016: Comparisons with Regional Chemical Transport Model simulations

    Science.gov (United States)

    Taketani, F.; Miyakawa, T.; Takigawa, M.; Yamaguchi, M.; Kanaya, Y.; Komazaki, Y.; Takashima, H.; Mordovskoi, P.; Tohjima, Y.

    2017-12-01

    Black carbon (BC), formed through the incomplete combustion of fossil fuels, biofuels, and biomass, is a major component of light-absorbing particulate matter in the atmosphere, causing positive radiative forcing. Also, BC deposition on the surface reduces the Earth's albedo and accelerates snow/ice melting by absorbing the sunlight. Therefore, the impact of BC on the Arctic climate needs to be assessed; however, observational information has been still insufficient. Over the Arctic Ocean, we have been conducting ship-based BC observations using a single particle soot photometer (SP2) on R/V Mirai every summer since 2014. To estimate the transport pathways of BC, we have also conducted model simulations during the period of cruise using a regional transport model (WRF-Chem 3.8.1). Here we focus on observations conducted on-board the R/V Mirai from 22 August to 5 October 2016 in a round trip to the Arctic Ocean through the Bering Strait from a port of Hachinohe (40.52N, 141.51E), Japan. We captured relatively high BC mass concentration events in this observation. The observed average BC mass concentration during 2016 was 0.8 ± 1.4 ng/m3 in >70N, similar to the levels ( 1.0ng/m3) recorded during our previous observations in the Arctic during 2014 and 2015. The variations in the observed concentrations in 2016 were qualitatively well reproduced by the regional chemical transport model. Quantitatively, however, the model tended to overestimate the BC levels, suggesting the possibilities that the emission rates were overestimated and/or the removal rates were underestimated. We will present further analysis on the size distribution, coating, and possible sources.

  17. Governance of Arctic Offshore Oil and Gas

    DEFF Research Database (Denmark)

    Bringing together leading experts from various disciplines, this book offers a comprehensive study of the governance of offshore oil and gas activities in the circumpolar Arctic. As a consequence of energy globalisation, and of a sharp increase in world energy demand, the Arctic Ocean is also now...... being targeted for its offshore oil and gas resources, at the same time as an increasing demand for democratic legitimisation and recognition of the rights of indigenous peoples is emerging in the civil spheres of society. The volume analyses how, in the daunting context of climate change......, the interactions between the various levels of governance structure the policy process and impact on the efficiency of environmental management and the effectiveness of public participation, including the participation of indigenous peoples. Any governance system for Arctic offshore oil and gas activities...

  18. Towards an assessment of riverine dissolved organic carbon in surface waters of the western Arctic Ocean based on remote sensing and biogeochemical modeling

    Science.gov (United States)

    Le Fouest, Vincent; Matsuoka, Atsushi; Manizza, Manfredi; Shernetsky, Mona; Tremblay, Bruno; Babin, Marcel

    2018-03-01

    Future climate warming of the Arctic could potentially enhance the load of terrigenous dissolved organic carbon (tDOC) of Arctic rivers due to increased carbon mobilization within watersheds. A greater flux of tDOC might impact the biogeochemical processes of the coastal Arctic Ocean (AO) and ultimately its capacity to absorb atmospheric CO2. In this study, we show that sea-surface tDOC concentrations simulated by a physical-biogeochemical coupled model in the Canadian Beaufort Sea for 2003-2011 compare favorably with estimates retrieved by satellite imagery. Our results suggest that, over spring-summer, tDOC of riverine origin contributes to 35 % of primary production and that an equivalent of ˜ 10 % of tDOC is exported westwards with the potential of fueling the biological production of the eastern Alaskan nearshore waters. The combination of model and satellite data provides promising results to extend this work to the entire AO so as to quantify, in conjunction with in situ data, the expected changes in tDOC fluxes and their potential impact on the AO biogeochemistry at basin scale.

  19. Simulation of optimal arctic routes using a numerical sea ice model based on an ice-coupled ocean circulation method

    OpenAIRE

    Jong-Ho Nam; Inha Park; Ho Jin Lee; Mi Ok Kwon; Kyungsik Choi; Young-Kyo Seo

    2013-01-01

    Ever since the Arctic region has opened its mysterious passage to mankind, continuous attempts to take advantage of its fastest route across the region has been made. The Arctic region is still covered by thick ice and thus finding a feasible navigating route is essential for an economical voyage. To find the optimal route, it is necessary to establish an efficient transit model that enables us to simulate every possible route in advance. In this work, an enhanced algorithm to determine the o...

  20. Ocean basin volume constraints on global sea level since the Jurassic

    Science.gov (United States)

    Seton, M.; Müller, R. D.

    2011-12-01

    Changes in the volume of the ocean basins, predominately via changes in the age-area distribution of oceanic lithosphere, have been suggested as the main driver for long-term eustatic sea-level change. As ocean lithosphere cools and thickens, ocean depth increases. The balance between the abundance of hot and buoyant crust along mid ocean ridges relative to abyssal plains is the primary driving force of long-term sea level changes. The emplacement of volcanic plateaus and chains as well as sedimentation contribute to raising eustatic sea level. Quantifying the average ocean basin depth through time primarily relies on the present day preserved seafloor spreading record, an analysis of the spatio-temporal record of plate boundary processes recorded on the continental margins adjacent to ocean basins as well as a consideration of the rules of plate tectonics, to reconstruct the history of seafloor spreading in the oceanic basins through time. This approach has been successfully applied to predict the magnitude and pattern of eustatic sea-level change since the Cretaceous (Müller et. al. 2008) but uncertainties in reconstructing mid ocean ridges and flanks increase back through time, given that we mainly depend on information preserved in preserved ocean crust. We have reconstructed the age-area distribution of oceanic lithosphere and the plate boundary configurations back to the Jurassic (200 Ma) in order to assess long-term sea-level change from amalgamation to dispersal of Pangaea. We follow the methodology presented in Müller et. al. (2008) but incorporate a new absolute plate motion model derived from Steinberger and Torsvik (2008) prior to 100 Ma, a merged Wessel et. al. (2006) and Wessel and Kroenke (2008) fixed Pacific hotspot reference frame, and a revised model for the formation of Panthalassa and the Cretaceous Pacific. Importantly, we incorporate a model for the break-up of the Ontong Java-Manihiki-Hikurangi plateaus between 120-86 Ma. We extend a

  1. Ocean Optics Protocols for Satellite Ocean Color Sensor Validation. Volume 2; Revised

    Science.gov (United States)

    Mueller, James L. (Editor); Fargion, Giulietta S. (Editor); Trees, C.; Austin, R. W.; Pietras, C. (Editor); Hooker, S.; Holben, B.; McClain, Charles R.; Clark, D. K.; Yuen, M.

    2002-01-01

    This document stipulates protocols for measuring bio-optical and radiometric data for the SIMBIOS Project. It supersedes the earlier version, and is organized into four parts: Introductory Background, Instrument Characteristics, Field Measurements and Data Analysis, Data Reporting and Archival. Changes in this revision include the addition of three new chapters: (1) Fundamental Definitions, Relationships and Conventions; (2) MOBY, A Radiometric Buoy for Performance Monitoring and Vicarious Calibration of Satellite Ocean Color Sensors: Measurement and Data Analysis Protocols; and (3) Normalized Water-Leaving Radiance and Remote Sensing Reflectance: Bidirectional Reflectance and Other Factors. Although the present document represents another significant, incremental improvement in the ocean optics protocols, there are several protocols that have either been overtaken by recent technological progress, or have been otherwise identified as inadequate. Revision 4 is scheduled for completion sometime in 2003. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational Project. The contributions are published as submitted, after only minor editing to correct obvious grammatical or clerical errors.

  2. Ocean Optics Protocols for Satellite Ocean Color Sensor Validation. Volume 1; Revised

    Science.gov (United States)

    Mueller, James L. (Editor); Fargion, Giulietta (Editor); Mueller, J. L.; Trees, C.; Austin, R. W.; Pietras, C.; Hooker, S.; Holben, B.; McClain, Charles R.; Clark, D. K.; hide

    2002-01-01

    This document stipulates protocols for measuring bio-optical and radiometric data for the SIMBIOS Project. It supersedes the earlier version, and is organized into four parts: Introductory Background, Instrument Characteristics, Field Measurements and Data Analysis, Data Reporting and Archival. Changes in this revision include the addition of three new chapters: (1) Fundamental Definitions, Relationships and Conventions; (2) MOBY, A Radiometric Buoy for Performance Monitoring and Vicarious Calibration of Satellite Ocean Color Sensors: Measurement and Data Analysis Protocols; and (3) Normalized Water-Leaving Radiance and Remote Sensing Reflectance: Bidirectional Reflectance and Other Factors. Although the present document represents another significant, incremental improvement in the ocean optics protocols, there are several protocols that have either been overtaken by recent technological progress, or have been otherwise identified as inadequate. Revision 4 is scheduled for completion sometime in 2003. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational Project. The contributions are published as submitted, after only minor editing to correct obvious grammatical or clerical errors.

  3. Temperature dependence of CO2-enhanced primary production in the European Arctic Ocean, supplement to: Holding, Johnna; Duarte, Carlos M; Sanz-Martín, Marina; Mesa, E; Arrieta, J M; Chierici, Melissa; Hendriks, Iris; García-Corral, L S; Regaudie-de-Gioux, A; Delgado, A; Reigstad, M; Wassmann, P; Agustí, Susana (2015): Temperature dependence of CO2-enhanced primary production in the European Arctic Ocean. Nature Climate Change, 5(12), 1079-1082

    KAUST Repository

    Holding, Johnna

    2016-01-01

    The Arctic Ocean is warming at two to three times the global rate and is perceived to be a bellwether for ocean acidification. Increased CO2 concentrations are expected to have a fertilization effect on marine autotrophs, and higher temperatures should lead to increased rates of planktonic primary production. Yet, simultaneous assessment of warming and increased CO2 on primary production in the Arctic has not been conducted. Here we test the expectation that CO2-enhanced gross primary production (GPP) may be temperature dependent, using data from several oceanographic cruises and experiments from both spring and summer in the European sector of the Arctic Ocean. Results confirm that CO2 enhances GPP (by a factor of up to ten) over a range of 145-2,099?µatm; however, the greatest effects are observed only at lower temperatures and are constrained by nutrient and light availability to the spring period. The temperature dependence of CO2-enhanced primary production has significant implications for metabolic balance in a warmer, CO2-enriched Arctic Ocean in the future. In particular, it indicates that a twofold increase in primary production during the spring is likely in the Arctic.

  4. Loki's Castle: Discovery and geology of a black smoker vent field at the Arctic Mid-Ocean Ridge

    Science.gov (United States)

    Pedersen, R.; Thorseth, I. H.; Lilley, M. D.; Barriga, F. J.; Früh-Green, G.; Nakamura, K.

    2010-12-01

    Previous attempts to locate hydrothermal vent fields and unravel the nature of venting at the ultraslow spreading and magma starved parts of the Arctic Mid Ocean Ridge (AMOR) have been unsuccessful. A black smoker vent field was eventually discovered at the Mohns-Knipovich bend at 73.5°N in 2008, and the field was revisited in 2009 and 2010. The Loki’s Castle vent field is located on the crest of an axial volcanic ridge that is bordered by a tectonic terrain dominated by core complexes to the NW, and a ridge flank that is buried by sediments from the Bear Island Fan to the SE. Fluid compositions are anomalous to other basalt-hosted fields and indicate interactions with sediments at depths. The vent field is associated with an unusually large hydrothermal deposit, which documents that extensive venting occurs at ultraslow spreading ridges despite the strongly reduced magmatic heat budget. ROV surveys have shown that venting occurs in two areas separated by around 100 m. Micro-bathymetry acquired by a Hugin AUV documents that two 20-30 tall mounds that coalesce at the base have developed around the vent sites. The micro-bathymetry also shows that the venting is located above two normal faults that define the NW margin of a rift that runs along the crest of the volcano. The black smoker fluids reach 317 °C, with an end-member SiO2 content of 16 mmol/kg. End-member chlorinity is around 85% of seawater suggesting that the fluids have phase-separated at depth. The fluid compositions indicate that the rock-water reactions occur around 2 km below the seafloor. The crustal thickness is estimated to be 4 +/- 0.5 km in the area. Whereas the depth of the reaction zone is comparable with faster spreading ridges, the fraction of crust cooled convectively by hydrothermal circulation is two times that of vent fields at ridges with normal crustal thickness.

  5. Arctic Ocean CO2 uptake: an improved multiyear estimate of the air-sea CO2 flux incorporating chlorophyll a concentrations

    Science.gov (United States)

    Yasunaka, Sayaka; Siswanto, Eko; Olsen, Are; Hoppema, Mario; Watanabe, Eiji; Fransson, Agneta; Chierici, Melissa; Murata, Akihiko; Lauvset, Siv K.; Wanninkhof, Rik; Takahashi, Taro; Kosugi, Naohiro; Omar, Abdirahman M.; van Heuven, Steven; Mathis, Jeremy T.

    2018-03-01

    We estimated monthly air-sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60° N from 1997 to 2014. This was done by mapping partial pressure of CO2 in the surface water (pCO2w) using a self-organizing map (SOM) technique incorporating chlorophyll a concentration (Chl a), sea surface temperature, sea surface salinity, sea ice concentration, atmospheric CO2 mixing ratio, and geographical position. We applied new algorithms for extracting Chl a from satellite remote sensing reflectance with close examination of uncertainty of the obtained Chl a values. The overall relationship between pCO2w and Chl a was negative, whereas the relationship varied among seasons and regions. The addition of Chl a as a parameter in the SOM process enabled us to improve the estimate of pCO2w, particularly via better representation of its decline in spring, which resulted from biologically mediated pCO2w reduction. As a result of the inclusion of Chl a, the uncertainty in the CO2 flux estimate was reduced, with a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tg C yr-1. Seasonal to interannual variation in the CO2 influx was also calculated.

  6. Measurement of Ice-nucleating Particles over the Western North Pacific, Bering Sea, and Arctic Ocean during a R/V Mirai Cruise in 2016

    Science.gov (United States)

    Murata, K.; Tobo, Y.; Taketani, F.; Miyakawa, T.; Kanaya, Y.

    2017-12-01

    Measurement of ice-nucleating particles (INPs) was performed using aerosol samples collected during a cruise of R/V Mirai across the western North Pacific, Bering Sea, and Arctic Ocean from August to October, 2016. We used the National Institute of Polar Research Cryogenic Refrigerator Applied to Freezing Test (NIPR-CRAFT) device to examine the immersion freezing efficiency of the collected aerosols in the temperature range of -25°C to 0°C and measured the number concentration of atmospheric INPs. The INP concentrations varied over about three orders of magnitude during the cruise. Over the Arctic Ocean (i.e., >70°N), the INPs were simulations, extremely high concentrations of INPs during the returning leg would be attributed to transport of smoke from fires in Siberia. Different INP concentrations during the cruise indicates that INPs in marine air can vary dramatically in response to long-range transport of continental aerosols, such as smoke, in addition to local emissions from the sea surface. The observed concentrations of INPs were reasonably well expressed by power law fits with the number concentration of fluorescent biological aerosol particles simultaneously measured with a Waveband Integrated Bioaerosol Sensor (WIBS-4) during the cruise, which suggests that biological aerosol particles may play a role in determining INP populations in the marine air of this case.

  7. Turbulent Mixing and Vertical Heat Transfer in the Surface Mixed Layer of the Arctic Ocean: Implication of a Cross-Pycnocline High-Temperature Anomaly

    Science.gov (United States)

    Kawaguchi, Yusuke; Takeda, Hiroki

    2017-04-01

    This study focuses on the mixing processes in the vicinity of surface mixed layer (SML) of the Arctic Ocean. Turbulence activity and vertical heat transfer are quantitatively characterized in the Northwind Abyssal Plain, based on the RV Mirai Arctic cruise, during the transition from late summer to early winter 2014. During the cruise, noticeable storm events were observed, which came over the ship's location and contributed to the deepening of the SML. According to the ship-based microstructure observation, within the SML, the strong wind events produced enhanced dissipation rates of turbulent kinetic energy in the order of magnitude of ɛ = 10-6-10-4W kg-1. On thermal variance dissipation rate, χ increases toward the base of SML, reaching O(10-7) K2 s-1, resulting in vertical heat flux of O(10) W m-2. During the occasional energetic mixing events, the near-surface warm water was transferred downward and penetrated through the SML base, creating a cross-pycnocline high-temperature anomaly (CPHTA) at approximately 20-30 m depth. Near CPHTA, the vertical heat flux was anomalously magnified to O(10-100) W m-2. Following the fixed-point observation, in the regions of marginal and thick ice zones, the SML heat content was monitored using an autonomous drifting buoy, UpTempO. During most of the ice-covered period, the ocean-to-ice turbulent heat flux was dominant, rather than the diapycnal heat transfer across the SML bottom interface.

  8. Evolution of a Western Arctic Ice Ocean Boundary Layer and Mixed Layer Across a Developing Thermodynamically Forced Marginal Ice Zone

    Science.gov (United States)

    2016-09-01

    heat and momentum transfer with the ice-ocean interface. These two observations demonstrate the intricate interplay between momentum, heat , and...summer evolution events: 1. Modulated shortwave radiative input to the ocean 2. Shoaled the ocean boundary layer increasing ocean heat storage 3... transfer in a stratified oceanic boundary layer. J. Geophys. Res., 92(C7), 6977–7986, doi:10.1029/JC092iC07p06977. McPhee, M. G., 1992: Turbulent heat

  9. Simulation of optimal arctic routes using a numerical sea ice model based on an ice-coupled ocean circulation method

    Directory of Open Access Journals (Sweden)

    Jong-Ho Nam

    2013-06-01

    Full Text Available Ever since the Arctic region has opened its mysterious passage to mankind, continuous attempts to take advantage of its fastest route across the region has been made. The Arctic region is still covered by thick ice and thus finding a feasible navigating route is essential for an economical voyage. To find the optimal route, it is necessary to establish an efficient transit model that enables us to simulate every possible route in advance. In this work, an enhanced algorithm to determine the optimal route in the Arctic region is introduced. A transit model based on the simulated sea ice and environmental data numerically modeled in the Arctic is developed. By integrating the simulated data into a transit model, further applications such as route simulation, cost estimation or hindcast can be easily performed. An interactive simulation system that determines the optimal Arctic route using the transit model is developed. The simulation of optimal routes is carried out and the validity of the results is discussed.

  10. Future Arctic climate changes: Adaptation and mitigation time scales

    Science.gov (United States)

    Overland, James E.; Wang, Muyin; Walsh, John E.; Stroeve, Julienne C.

    2014-02-01

    The climate in the Arctic is changing faster than in midlatitudes. This is shown by increased temperatures, loss of summer sea ice, earlier snow melt, impacts on ecosystems, and increased economic access. Arctic sea ice volume has decreased by 75% since the 1980s. Long-lasting global anthropogenic forcing from carbon dioxide has increased over the previous decades and is anticipated to increase over the next decades. Temperature increases in response to greenhouse gases are amplified in the Arctic through feedback processes associated with shifts in albedo, ocean and land heat storage, and near-surface longwave radiation fluxes. Thus, for the next few decades out to 2040, continuing environmental changes in the Arctic are very likely, and the appropriate response is to plan for adaptation to these changes. For example, it is very likely that the Arctic Ocean will become seasonally nearly sea ice free before 2050 and possibly within a decade or two, which in turn will further increase Arctic temperatures, economic access, and ecological shifts. Mitigation becomes an important option to reduce potential Arctic impacts in the second half of the 21st century. Using the most recent set of climate model projections (CMIP5), multimodel mean temperature projections show an Arctic-wide end of century increase of +13°C in late fall and +5°C in late spring for a business-as-usual emission scenario (RCP8.5) in contrast to +7°C in late fall and +3°C in late spring if civilization follows a mitigation scenario (RCP4.5). Such temperature increases demonstrate the heightened sensitivity of the Arctic to greenhouse gas forcing.

  11. Human-induced Arctic moistening.

    Science.gov (United States)

    Min, Seung-Ki; Zhang, Xuebin; Zwiers, Francis

    2008-04-25

    The Arctic and northern subpolar regions are critical for climate change. Ice-albedo feedback amplifies warming in the Arctic, and fluctuations of regional fresh water inflow to the Arctic Ocean modulate the deep ocean circulation and thus exert a strong global influence. By comparing observations to simulations from 22 coupled climate models, we find influence from anthropogenic greenhouse gases and sulfate aerosols in the space-time pattern of precipitation change over high-latitude land areas north of 55 degrees N during the second half of the 20th century. The human-induced Arctic moistening is consistent with observed increases in Arctic river discharge and freshening of Arctic water masses. This result provides new evidence that human activity has contributed to Arctic hydrological change.

  12. Graduate training in Earth science across borders and disciplines: ArcTrain -"Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic"

    Science.gov (United States)

    Stein, Rüdiger; Kucera, Michal; Walter, Maren; de Vernal, Anne

    2015-04-01

    Due to a complex set of feedback processes collectively known as "polar amplification", the Arctic realm is expected to experience a greater-than-average response to global climate forcing. The cascades of feedback processes that connect the Arctic cryosphere, ocean and atmosphere remain incompletely constrained by observations and theory and are difficult to simulate in climate models. Our capacity to predict the future of the region and assess the impacts of Arctic change processes on global and regional environments hinges on the availability of interdisciplinary experts with strong international experience and understanding of the science/society interface. This is the basis of the International Research Training Group "Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic - ArcTrain", which was initiated in 2013. ArcTrain aims to educate PhD students in an interdisciplinary environment that combines paleoclimatology, physical oceanography, remote sensing and glaciology with comprehensive Earth system modelling, including sea-ice and ice-sheet components. The qualification program for the PhD students includes joint supervision, mandatory research residences at partner institutions, field courses on land and on sea (Floating University), annual meetings and training workshops and a challenging structured training in expert skills and transferrable skills. Its aim is to enhance the career prospects and employability of the graduates in a challenging international job market across academic and applied sectors. ArcTrain is a collaborative project at the University of Bremen and the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven. The German part of the project is designed to continue for nine years and educate three cohorts of twelve PhD students each. The Canadian partners comprise a consortium of eight universities led by the GEOTOP cluster at the Université du Québec à Montréal and including

  13. FRAM (FRontiers in Arctic marine Monitoring: The FRAM Ocean Observing System) planned efforts for integrated water column biogeochemistry

    Science.gov (United States)

    Nielsdóttir, Maria; Salter, Ian; Kanzow, Torsten; Boetius, Antje

    2015-04-01

    The Arctic is a region undergoing rapid environmental change and will be subject to multiple stressors in the coming decades. Reductions in sea ice concentration; warming, increased terrigenous inputs and Atlantification are all expected to exert a significant impact on the structure and function of Arctic ecosystems. The Fram Strait is a particularly important region because it acts as a gateway in the exchange of Atlantic and Arctic water masses. The logistical constraints in conducting year round biogeochemical measurements in such areas impose a significant limitation to our understanding of these complicated ecosystems. To address these important challenges the German ministry of research has funded a multi-million Euro infrastructure project (FRAM). Over the next five years FRAM will develop a remote access and autonomous sampling infrastructure to improve the temporal and spatial resolution of biogeochemical measurements in the Fram Strait and central Arctic. Here we present a summary of sampling strategies, technological innovations and biogeochemical parameters that will be addressed over the duration of the project. Specific emphasis will be placed on platforms for monitoring nutrient dynamics, carbonate chemistry, organic carbon flux and the development of a sustained microbial observatory.

  14. Arctic Shipping

    DEFF Research Database (Denmark)

    Hansen, Carsten Ørts; Grønsedt, Peter; Lindstrøm Graversen, Christian

    This report forms part of the ambitious CBS Maritime research initiative entitled “Competitive Challenges and Strategic Development Potential in Global Maritime Industries” which was launched with the generous support of the Danish Maritime Fund. The competitiveness initiative targets specific ma......, the latter aiming at developing key concepts and building up a basic industry knowledge base for further development of CBS Maritime research and teaching. This report attempts to map the opportunities and challenges for the maritime industry in an increasingly accessible Arctic Ocean...

  15. The behaviour of 129I released from nuclear fuel reprocessing factories in the North Atlantic Ocean and transport to the Arctic assessed from numerical modelling

    International Nuclear Information System (INIS)

    Villa, M.; López-Gutiérrez, J.M.; Suh, Kyung-Suk; Min, Byung-Il; Periáñez, R.

    2015-01-01

    Highlights: • Dispersion of 129 I released from nuclear facilities evaluated by numerical modelling in the Atlantic. • Model validated through comparisons with field measurements. • 5.1 and 16.6 TBq of 129 I have been introduced in the Arctic from Sellafield and La Hague. • The distribution of 129 I among several shelf seas and regions has been evaluated. • Mean ages of tracers obtained: about 3.5 year larger for Sellafield than for La Hague releases. - Abstract: A quantitative evaluation of the fate of 129 I, released from the European reprocessing plants of Sellafield (UK) and La Hague (France), has been made by means of a Lagrangian dispersion model. Transport of radionuclides to the Arctic Ocean has been determined. Thus, 5.1 and 16.6 TBq of 129 I have been introduced in the Arctic from Sellafield and La Hague respectively from 1966 to 2012. These figures represent, respectively, 48% and 55% of the cumulative discharge to that time. Inventories in the North Atlantic, including shelf seas, are 4.4 and 13.8 TBq coming from Sellafield and La Hague respectively. These figures are significantly different from previous estimations based on field data. The distribution of these inventories among several shelf seas and regions has been evaluated as well. Mean ages of tracers have been finally obtained, making use of the age-averaging hypothesis. It has been found that mean ages for Sellafield releases are about 3.5 year larger than for La Hague releases

  16. Ocean circulation and shelf processes in the Arctic, Mediterranean traced by radiogenic neodymium isotopes, rare earth elements and stable oxygen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Laukert, Georgi

    2017-02-20

    Disentangling the sources, distribution and mixing of water masses involved in the transport and transfer of heat and freshwater in the Arctic Mediterranean (i.e. the Arctic Ocean and the Nordic Seas, AM) is critical for the understanding of present and future hydrological changes in the high-latitude regions. This study refines the knowledge of water mass circulation in the AM and provides new insights into the processes occurring on the Arctic shelves and in high-latitude estuaries. A multi-proxy approach is used combining dissolved radiogenic Nd isotopes (ε{sub Nd}), rare earth elements (REEs) and stable oxygen isotopes (δ{sup 18}O) together with standard hydrographic tracers. The sources, distribution and mixing of water masses that circulate in the AM and pass the Fram Strait are assessed through evaluation of dissolved ε{sub Nd} and REE, and δ{sup 18}O data obtained from samples recovered in 2012, 2014 and 2015, and through a compilation and reassessment of literature Nd isotope and concentration data previously reported for other sites within the AM. The Nd isotope and REE distribution in the central Fram Strait and the open AM is shown to primarily reflect the lateral advection of water masses and their mixing, whereas seawater-particle interactions exert important control only above the shelf regions. New insights into the processes occurring in high latitude estuaries are provided by dissolved Nd isotope and REE compositions together with δ{sup 18}O data for the Laptev Sea based on filtered samples recovered in 2012, 2013 and 2014. A combination of REE removal through coagulation of nanoparticles and colloids and REE redistribution within the water column through formation and melting of sea ice and river ice is suggested to account for the distribution of all REEs, while no REE release from particles is observed. The ice-related processes contribute to the redistribution of other elements and ultimately may also affect primary productivity in high

  17. Freshwater Export from the Arctic Ocean and its Downstream Effect on Labrador Sea Deep Convection in a High-Resolution Numerical Model

    Science.gov (United States)

    2010-12-01

    Arctic has been observed in the northern Canadian Arctic Archipelago ( Bourke and McLaren 1992). There, thick multiyear ice of Arctic origin encounters...Affairs, 87(2), 63-77. 172 Bourke , R. H., and A. S. McLaren, 1992: Contour mapping of Arctic Basin ice draft and roughness parameters. J. Geophys

  18. Modeling plankton ecosystem functioning and nitrogen fluxes in the oligotrophic waters of the Beaufort Sea, Arctic Ocean: a focus on light-driven processes

    Directory of Open Access Journals (Sweden)

    V. Le Fouest

    2013-07-01

    Full Text Available The Arctic Ocean (AO undergoes profound changes of its physical and biotic environments due to climate change. In some areas of the Beaufort Sea, the stronger haline stratification observed in summer alters the plankton ecosystem structure, functioning and productivity, promoting oligotrophy. A one-dimension (1-D physical–biological coupled model based on the large multiparametric database of the Malina project in the Beaufort Sea was used (i to infer the plankton ecosystem functioning and related nitrogen fluxes and (ii to assess the model sensitivity to key light-driven processes involved in nutrient recycling and phytoplankton growth. The coupled model suggested that ammonium photochemically produced from photosensitive dissolved organic nitrogen (i.e., photoammonification process was a necessary nitrogen source to achieve the observed levels of microbial biomass and production. Photoammonification directly and indirectly (by stimulating the microbial food web activity contributed to 70% and 18.5% of the 0–10 m and whole water column, respectively, simulated primary production (respectively 66% and 16% for the bacterial production. The model also suggested that variable carbon to chlorophyll ratios were required to simulate the observed herbivorous versus microbial food web competition and realistic nitrogen fluxes in the Beaufort Sea oligotrophic waters. In face of accelerating Arctic warming, more attention should be paid in the future to the mechanistic processes involved in food webs and functional group competition, nutrient recycling and primary production in poorly productive waters of the AO, as they are expected to expand rapidly.

  19. High-resolution sub-bottom seismic and sediment core records from the Chukchi Abyssal Plain reveal Quaternary glaciation impacts on the western Arctic Ocean

    Science.gov (United States)

    Joe, Y. J.; Seokhoon, Y.; Nam, S. I.; Polyak, L.; Niessen, F.

    2017-12-01

    For regional context of the Quaternary history of Arctic marine glaciations, such as glacial events in northern North America and on the Siberian and Chukchi margins, we used CHIRP sub-bottom profiles (SBP) along with sediment cores, including a 14-m long piston core ARA06-04JPC taken from the Chukchi abyssal plain during the RV Araon expedition in 2015. Based on core correlation with earlier developed Arctic Ocean stratigraphies using distribution of various sedimentary proxies, core 04JPC is estimated to extend to at least Marine Isotope Stage 13 (>0.5 Ma). The stratigraphy developed for SBP lines from the Chukchi abyssal plain to surrounding slopes can be divided into four major seismostratigraphic units (SSU 1-4). SBP records from the abyssal plain show well preserved stratification, whereas on the surrounding slopes this pattern is disrupted by lens-shaped, acoustically transparent sedimentary bodies interpreted as glaciogenic debris flow deposits. Based on the integration of sediment physical property and SBP data, we conclude that these debris flows were generated during several ice-sheet grounding events on the Chukchi and East Siberian margins, including adjacent ridges and plateaus, during the middle to late Quaternary.

  20. Winter Arctic sea ice growth: current variability and projections for the coming decades

    Science.gov (United States)

    Petty, A.; Boisvert, L.; Webster, M.; Holland, M. M.; Bailey, D. A.; Kurtz, N. T.; Markus, T.

    2017-12-01

    Arctic sea ice increases in both extent and thickness during the cold winter months ( October to May). Winter sea ice growth is an important factor controlling ocean ventilation and winter water/deep water formation, as well as determining the state and vulnerability of the sea ice pack before the melt season begins. Key questions for the Arctic community thus include: (i) what is the current magnitude and variability of winter Arctic sea ice growth and (ii) how might this change in a warming Arctic climate? To address (i), our current best guess of pan-Arctic sea ice thickness, and thus volume, comes from satellite altimetry observations, e.g. from ESA's CryoSat-2 satellite. A significant source of uncertainty in these data come from poor knowledge of the overlying snow depth. Here we present new estimates of winter sea ice thickness from CryoSat-2 using snow depths from a simple snow model forced by reanalyses and satellite-derived ice drift estimates, combined with snow depth estimates from NASA's Operation IceBridge. To address (ii), we use data from the Community Earth System Model's Large Ensemble Project, to explore sea ice volume and growth variability, and how this variability might change over the coming decades. We compare and contrast the model simulations to observations and the PIOMAS ice-ocean model (over recent years/decades). The combination of model and observational analysis provide novel insight into Arctic sea ice volume variability.

  1. Analysis of the Arctic system for freshwater cycle intensification: Observations and expectations

    Science.gov (United States)

    Rawlins, M.A.; Steele, M.; Holland, M.M.; Adam, J.C.; Cherry, J.E.; Francis, J.A.; Groisman, P.Y.; Hinzman, L.D.; Huntington, T.G.; Kane, D.L.; Kimball, J.S.; Kwok, R.; Lammers, R.B.; Lee, C.M.; Lettenmaier, D.P.; McDonald, K.C.; Podest, E.; Pundsack, J.W.; Rudels, B.; Serreze, Mark C.; Shiklomanov, A.; Skagseth, O.; Troy, T.J.; Vorosmarty, C.J.; Wensnahan, M.; Wood, E.F.; Woodgate, R.; Yang, D.; Zhang, K.; Zhang, T.

    2010-01-01

    Hydrologic cycle intensification is an expected manifestation of a warming climate. Although positive trends in several global average quantities have been reported, no previous studies have documented broad intensification across elements of the Arctic freshwater cycle (FWC). In this study, the authors examine the character and quantitative significance of changes in annual precipitation, evapotranspiration, and river discharge across the terrestrial pan-Arctic over the past several decades from observations and a suite of coupled general circulation models (GCMs). Trends in freshwater flux and storage derived from observations across the Arctic Ocean and surrounding seas are also described. With few exceptions, precipitation, evapotranspiration, and river discharge fluxes from observations and the GCMs exhibit positive trends. Significant positive trends above the 90% confidence level, however, are not present for all of the observations. Greater confidence in the GCM trends arises through lower interannual variability relative to trend magnitude. Put another way, intrinsic variability in the observations tends to limit confidence in trend robustness. Ocean fluxes are less certain, primarily because of the lack of long-term observations. Where available, salinity and volume flux data suggest some decrease in saltwater inflow to the Barents Sea (i.e., a decrease in freshwater outflow) in recent decades. A decline in freshwater storage across the central Arctic Ocean and suggestions that large-scale circulation plays a dominant role in freshwater trends raise questions as to whether Arctic Ocean freshwater flows are intensifying. Although oceanic fluxes of freshwater are highly variable and consistent trends are difficult to verify, the other components of the Arctic FWC do show consistent positive trends over recent decades. The broad-scale increases provide evidence that the Arctic FWC is experiencing intensification. Efforts that aim to develop an adequate

  2. Pollution of the Marine Environment by Dumping: Legal Framework Applicable to Dumped Chemical Weapons and Nuclear Waste in the Arctic Ocean

    OpenAIRE

    Lott, Alexander

    2016-01-01

    The Arctic seas are the world’s biggest dumping ground for sea-disposed nuclear waste and have served among the primary disposal sites for chemical warfare agents. Despite of scientific uncertainty, the Arctic Council has noted that this hazardous waste still affects adversely the Arctic marine environment and may have implications to the health of the Arctic people. The purpose of this manuscript is to establish the rights and obligations of the Arctic States in c...

  3. Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

    Science.gov (United States)

    Dong, C.; Bai, X.; Sheng, H.; Jiao, L.; Zhou, H.; Shao, Z.

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants that can be transferred long distances and tend to accumulate in marine sediments. However, less is known regarding the distribution of PAHs and their natural bioattenuation in the open sea, especially the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to the Makarov Basin in the summer of 2010. PAH compositions and total concentrations were examined with GC-MS. The concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g-1 dry weight and decreased with sediment depth and movement from the southern to the northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. The 16S rRNA gene of the total environmental DNA was analyzed with Illumina high-throughput sequencing (IHTS) to determine the diversity of bacteria involved in PAH degradation in situ. The potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant, occurred in all sediment samples. Meanwhile, enrichment with PAHs was initiated onboard and transferred to the laboratory for further enrichment and to obtain the degrading consortia. Most of the abovementioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas occurred alternately as predominant members in the enrichment cultures from different sediments based on IHTS and PCR-DGGE analysis. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus Pseudomonas showed the best degradation capability under low temperatures. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may

  4. Quaternary geology of the Duck Hawk Bluffs, southwest Banks Island, Arctic Canada: a re-investigation of a critical terrestrial type locality for glacial and interglacial events bordering the Arctic Ocean

    Science.gov (United States)

    Evans, David J. A.; England, John H.; La Farge, Catherine; Coulthard, Roy D.; Lakeman, Thomas R.; Vaughan, Jessica M.

    2014-05-01

    Duck Hawk Bluffs, southwest Banks Island, is a primary section (8 km long and 60 m high) in the western Canadian Arctic Archipelago exposing a long record of Quaternary sedimentation adjacent to the Arctic Ocean. A reinvestigation of Duck Hawk Bluffs demonstrates that it is a previously unrecognized thrust-block moraine emplaced from the northeast by Laurentide ice. Previous stratigraphic models of Duck Hawk Bluffs reported a basal unit of preglacial fluvial sand and gravel (Beaufort Fm, forested Arctic), overlain by a succession of three glaciations and at least two interglacials. Our observations dismiss the occurrence of preglacial sediments and amalgamate the entire record into three glacial intervals and one prominent interglacial. The first glacigenic sedimentation is recorded by an ice-contact sandur containing redeposited allochthonous organics previously assigned to the Beaufort Fm. This is overlain by fine-grained sediments with ice wedge pseudomorphs and well-preserved bryophyte assemblages corresponding to an interglacial environment similar to modern. The second glacial interval is recorded by ice-proximal mass flows and marine rhythmites that were glacitectonized when Laurentide ice overrode the site from Amundsen Gulf to the south. Sediments of this interval have been reported to be magnetically reversed (>780 ka). The third interval of glacigenic sedimentation includes glacifluvial sand and gravel recording the arrival of Laurentide ice that overrode the site from the northeast (island interior) depositing a glacitectonite and constructing the thrust block moraine that comprises Duck Hawk Bluffs. Sediments of this interval have been reported to be magnetically normal (Banks Island coalesced with an ice stream in Amundsen Gulf, depositing the interlobate Sachs Moraine that contains shells as young as ˜24 cal ka BP (Late Wisconsinan). During deglaciation, meltwater emanating from these separating ice lobes deposited outwash that extended to deglacial

  5. Warm mid-Cretaceous high-latitude sea-surface temperatures from the southern Tethys Ocean and cool high-latitude sea-surface temperatures from the Arctic Ocean: asymmetric worldwide distribution of dinoflagellates

    Science.gov (United States)

    Masure, Edwige; Desmares, Delphine; Vrielynck, Bruno

    2014-05-01

    Dealing with 87 articles and using a Geographical Information System, Masure and Vrielynck (2009) have mapped worldwide biogeography of 38 Late Albian dinoflagellate cysts and have demonstrated Cretaceous oceanic bioclimatic belts. For comparison 30 Aptian species derived from 49 studies (Masure et al., 2013) and 49 Cenomanian species recorded from 33 articles have been encountered. Tropical, Subtropical, Boreal, Austral, bipolar and cosmopolitan species have been identified and Cretaceous dinoflagellate biomes are introduced. Asymmetric distribution of Aptian and Late Albian/Cenomanian subtropical Tethyan species, from 40°N to 70°S, demonstrates asymmetric Aptian and Late Albian/Cenomanian Sea Surface Temperature (SST) gradients with warm water masses in high latitudes of Southern Ocean. The SST gradients were stronger in the Northern Hemisphere than in the Southern Hemisphere. We note that Aptian and Late Albian/Cenomanian dinoflagellates restricted to subtropical and subpolar latitudes met and mixed at 35-40°N, while they mixed from 30°S to 70°S and from 50°S to 70°S respectively in the Southern Hemisphere. Mixing belts extend on 5° in the Northern Hemisphere and along 40° (Aptian) and 20° (Late Albian/Cenomanian) in the Southern one. The board southern mixing belt of Tethyan and Austral dinoflagellates suggest co-occurrence of warm and cold currents. We record climatic changes such as the Early Aptian cooler period and Late Aptian and Albian warming through the poleward migration of species constrained to cool water masses. These species sensitive to temperature migrated from 35°N to 55°N through the shallow Greenland-Norwergian Seaway connecting the Central Atlantic and the Arctic Ocean. While Tethyan species did not migrate staying at 40°N. We suggest that the Greenland-Norwergian Seaway might has been a barrier until Late Albian/Cenomanian for oceanic Tethyan dinoflagellates stopped either by the shallow water column or temperature and salinity

  6. Iceberg and meltwater discharge events in the western Arctic Ocean since MIS 5: a comparison of sediment cores off the East Siberian and Chukchi margins

    Science.gov (United States)

    Xiao, W.; Wang, R.; Zhang, T.; Duan, X.; Polyak, L.

    2017-12-01

    In the Pleistocene the western Arctic Ocean was affected by deglacial discharge events from ice sheets in northern North America as well as the East Siberian and Chukchi margins. Distribution of Ice Rafted Debris (IRD) >250 μm and planktonic foraminiferal N. pachyderma (sin.) (Nps) δ18O and δ13C was compared in CHINARE sediment cores ARC2-M03 (Wang et al., 2013) and ARC3-P37 from the Chukchi Abyssal Plain and Northwind Ridge, respectively, to identify the impacts of icebergs and meltwater on paleoceanographic environments since MIS 5. The IRD is mainly composed of quartz grains and fragments of clastic rocks and detrital carbonates. The carbonates, mostly dolomites characteristic of the Canadian Arctic Archipelago (CAA) provenance, typically anti-correlate with quartz and clastic rocks, indicating different sources such as Chukchi-Alaskan or East Siberian margin. Most of the Nps δ18O depletions correspond to peaks in detrital carbonates, suggesting a strong influence of meltwater from the Laurentide Ice Sheet (LIS) on the western Arctic Ocean. A conspicuous dark gray interval interpreted to represent glacial/deglacial environments of MIS 4/3 age, shows a remarkable depletion in Nps δ13C along with high δ18O values and absence of IRD. This unusual signature may be related to a persistent sea-ice cover and/or high fluxes of terrigenous material with deglacial debris flows. In a younger grey interval corresponding to MIS2, high abundances of quartz and clastic rocks in the Northwind Ridge core ARC3-P37 indicate iceberg discharge from areas other than CAA, such as the Mackenzie LIS lobe or Chukchi-Alaskan margin. The MIS2-Holocene transition is marked by an increase in detrital carbonates co-occurring with Nps δ13C and δ18O depletion (Polyak et al., 2007), indicative of LIS iceberg/meltwater fluxes from the CAA. We note that stable-isotope events in the study area may go unnoticed because of gaps in foraminiferal records related to dissolution and/or adverse

  7. Arctic Ice Dynamics Joint Experiment (AIDJEX) 1975-1976, Physical Oceanography Data Report Profiling Current Meter Data -- Camp Caribou. Volume 1.

    Science.gov (United States)

    1980-02-01

    base of the ice. Hourly averages pertaining to the fixed-mast current meters can be obtained through the National Oceano - graphic Data Center. The...431 441 451 461 471 481 49t 50 40 ’II 421 431 441 󈧷j 461 4󈨋 481 491 Sol , 71ME :N :AYs Fig’ure 11. Speed and direction plotted for the manned AIDJEX...EDDIES Swift mesoscale undercurrents are one of the most notable oceano - graphic features observed in the AIDJEX area of the Arctic Ocean. The eddy form

  8. A 10,000-year record of Arctic Ocean sea-ice variability—view from the beach

    DEFF Research Database (Denmark)

    Funder, Svend Visby; Goosse, Hugues; Jepsen, Hans Festersen

    2011-01-01

    We present a sea-ice record from northern Greenland covering the past 10,000 years. Multiyear sea ice reached a minimum between ~8500 and 6000 years ago, when the limit of year-round sea ice at the coast of Greenland was located ~1000 kilometers to the north of its present position. The subsequen...... of uniformity in past sea-ice changes, which is probably related to large-scale atmospheric anomalies such as the Arctic Oscillation, is not well reproduced in models. This needs to be further explored, as it is likely to have an impact on predictions of future sea-ice distribution...

  9. Impacts of Siberian biomass burning on organic aerosols over the North Pacific Ocean and the Arctic: primary and secondary organic tracers.

    Science.gov (United States)

    Ding, Xiang; Wang, Xinming; Xie, Zhouqing; Zhang, Zhou; Sun, Liguang

    2013-04-02

    During the 2003 Chinese Arctic Research Expedition (CHINARE2003) from the Bohai Sea to the high Arctic (37°N-80°N), filter-based particle samples were collected and analyzed for tracers of primary and secondary organic aerosols (SOA) as well as water-soluble organic carbon (WSOC). Biomass burning (BB) tracer levoglucosan had comparatively much higher summertime average levels (476 ± 367 pg/m(3)) during our cruise due to the influence of intense forest fires then in Siberia. On the basis of 5-day back trajectories, samples with air masses passing through Siberia had organic tracers 1.3-4.4 times of those with air masses transporting only over the oceans, suggesting substantial contribution of continental emissions to organic aerosols in the marine atmosphere. SOA tracers from anthropogenic aromatics were negligible or not detected, while those from biogenic terpenenoids were ubiquitously observed with the sum of SOA tracers from isoprene (623 ± 414 pg/m(3)) 1 order of magnitude higher than that from monoterpenes (63 ± 49 pg/m(3)). 2-Methylglyceric acid as a product of isoprene oxidation under high-NOx conditions was dominant among SOA tracers, implying that these BSOA tracers were not formed over the oceans but mainly transported from the adjacent Siberia where a high-NOx environment could be induced by intense forest fires. The carbon fractions shared by biogenic SOA tracers and levoglucosan in WSOC in our ocean samples were 1-2 orders of magnitude lower than those previously reported in continental samples, BB emissions or chamber simulation samples, largely due to the chemical evolution of organic tracers during transport. As a result of the much faster decline in levels of organic tracers than that of WSOC during transport, the trace-based approach, which could well reconstruct WSOC using biogenic SOA and BB tracers for continental samples, only explained ∼4% of measured WSOC during our expedition if the same tracer-WSOC or tracer-SOC relationships were

  10. The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea

    Science.gov (United States)

    Pearce, Christof; Varhelyi, Aron; Wastegård, Stefan; Muschitiello, Francesco; Barrientos, Natalia; O'Regan, Matt; Cronin, Thomas M.; Gemery, Laura; Semiletov, Igor; Backman, Jan; Jakobsson, Martin

    2017-04-01

    The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenland. This large geographic distribution, combined with the fact that the eruption is relatively well constrained in time using radiocarbon dating of lake sediments and annual layer counts in ice cores, makes it an excellent stratigraphic marker for dating and correlating mid-late Holocene sediment and paleoclimate records. This study presents the outcome of a targeted search for the Aniakchak tephra in a marine sediment core from the Arctic Ocean, namely Core SWERUS-L2-2-PC1 (2PC), raised from 57 m water depth in Herald Canyon, western Chukchi Sea. High concentrations of tephra shards, with a geochemical signature matching that of Aniakchak ash, were observed across a more than 1.5 m long sediment sequence. Since the primary input of volcanic ash is through atmospheric transport, and assuming that bioturbation can account for mixing up to ca. 10 cm of the marine sediment deposited at the coring site, the broad signal is interpreted as sustained reworking at the sediment source input. The isochron is therefore placed at the base of the sudden increase in tephra concentrations rather than at the maximum concentration. This interpretation of major reworking is strengthened by analysis of grain size distribution which points to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset ΔR = 477 ± 60 years. This relatively high value may be explained by the major influence of typically carbon-old Pacific waters, and it agrees well with recent estimates of ΔR along the northwest Alaskan coast, possibly

  11. SCICEX: Submarine Arctic Science Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  12. Oceanographic profile Zooplankton biomass measurements collected using net in the Arctic Ocean from 1991 to 1995 (NODC Accession 0000970)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Mumm, Nicolai, H. Auel, H. Hanssen, W. Hagen, C. Richter, and H.J. Hirche. 1998. Breaking the ice: large-scale distribution of mesozooplankton after a decade of...

  13. Raw Knudsen Chirp 320BR subbottom profiler - Knudsen subbottom profile data for the Chukchi Cap and Arctic Ocean.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Knudsen Chirp 320BR subbottom profiler - Knudsen subbottom profile data were collected in Raw Knudsen SEG-Y Datagram format.

  14. Raw Knudsen 320B/R CHIRP Subbottom Profiler - CHIRP Subbottom Profiler data for the Arctic Ocean ECS survey.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Knudsen 320B/R CHIRP Subbottom Profiler - CHIRP Subbottom Profiler data were collected in Raw Knudsen SEG-Y Datagram format.

  15. The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

    KAUST Repository

    Có zar, André s; Martí , Elisa; Duarte, Carlos M.; Garcí a-de-Lomas, Juan; van Sebille, Erik; Ballatore, Thomas J.; Eguí luz, V. M.; Gonzá lez-Gordillo, J. Ignacio; Pedrotti, Maria L.; Echevarrí a, Fidel; Troublè , Romain; Irigoien, Xabier

    2017-01-01

    The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources

  16. Arctic Marine Transportation Program 1979-1986

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this program was to collect data relevant to developing year-round transportation capabilities in the Arctic Ocean. The US Maritime Administration...

  17. Sea ice contribution to the air-sea CO{sub 2} exchange in the Arctic and Southern Oceans

    Energy Technology Data Exchange (ETDEWEB)

    Rysgaard, Soeren (Greenland Climate Research Centre, Greenland Inst. of Natural Resources, Nuuk, Greenland (Denmark); Centre for Earth Observation Science, CHR Faculty of Environment Earth and Resources, Univ. of Manitoba, Winnipeg (Canada)), e-mail: rysgaard@natur.gl; Bendtsen, Joergen (Greenland Climate Research Centre, Greenland Inst. of Natural Resources, Nuuk, Greenland (Denmark); Centre for Ice and Climate, Niels Bohr Inst., Univ. of Copenhagen, Copenhagen O (Denmark)); Delille, Bruno (Unit' e d' Oceanographie Chimique, Interfacultary Centre for Marine Research, Universite de Liege, Liege (Belgium)); Dieckmann, Gerhard S. (Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany)); Glud, Ronnie N. (Greenland Climate Research Centre, Greenland Inst. of Natural Resources, Nuuk, Greenland (Denmark); Scottish Association of Marine Sciences, Scotland UK, Southern Danish Univ. and NordCee, Odense M (Denmark)); Kennedy, Hilary; Papadimitriou, Stathys (School of Ocean Sciences, Bangor Univ., Menai Bridge, Anglesey, Wales (United Kingdom)); Mortensen, John (Greenland Climate Research Centre, Greenland Inst. of Natural Resources, Nuuk, Greenland (Denmark)); Thomas, David N. (School of Ocean Sciences, Bangor Univ., Menai Bridge, Anglesey, Wales (United Kingdom); Finnish Environment Inst. (SYKE), Marine Research Centre, Helsinki (Finland)); Tison, Jean-Louis (Glaciology Unit, Dept. of Earth and Environmental Sciences, Universite Libre de Bruxelles, Bruxelles, (Belgium))

    2011-11-15

    Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO{sub 2} and the subsequent effect on air-sea CO{sub 2} exchange have received little attention. We review the mechanisms by which sea ice directly and indirectly controls the air-sea CO{sub 2} exchange and use recent measurements of inorganic carbon compounds in bulk sea ice to estimate that oceanic CO{sub 2} uptake during the seasonal cycle of sea-ice growth and decay in ice-covered oceanic regions equals almost half of the net atmospheric CO{sub 2} uptake in ice-free polar seas. This sea-ice driven CO{sub 2} uptake has not been considered so far in estimates of global oceanic CO{sub 2} uptake. Net CO{sub 2} uptake in sea-ice-covered oceans can be driven by; (1) rejection during sea-ice formation and sinking of CO{sub 2}-rich brine into intermediate and abyssal oceanic water masses, (2) blocking of air-sea CO{sub 2} exchange during winter, and (3) release of CO{sub 2}-depleted melt water with excess total alkalinity during sea-ice decay and (4) biological CO{sub 2} drawdown during primary production in sea ice and surface oceanic waters

  18. Distributions of low molecular weight dicarboxylic acids, ketoacids and α-dicarbonyls in the marine aerosols collected over the Arctic Ocean during late summer

    Directory of Open Access Journals (Sweden)

    K. Kawamura

    2012-11-01

    Full Text Available Oxalic and other small dicarboxylic acids have been reported as important water-soluble organic constituents of atmospheric aerosols from different environments. Their molecular distributions are generally characterized by the predominance of oxalic acid (C2 followed by malonic (C3 and/or succinic (C4 acids. In this study, we collected marine aerosols from the Arctic Ocean during late summer in 2009 when sea ice was retreating. The marine aerosols were analyzed for the molecular distributions of dicarboxylic acids as well as ketocarboxylic acids and α-dicarbonyls to better understand the source of water-soluble organics and their photochemical processes in the high Arctic marine atmosphere. We found that diacids are more abundant than ketoacids and α-dicarbonyls, but their concentrations are generally low (< 30 ng m−3, except for one sample (up to 70 ng m−3 that was collected near the mouth of Mackenzie River during clear sky condition. Although the molecular compositions of diacids are in general characterized by the predominance of oxalic acid, a depletion of C2 was found in two samples in which C4 became the most abundant. Similar depletion of oxalic acid has previously been reported in the Arctic aerosols collected at Alert after polar sunrise and in the summer aerosols from the coast of Antarctica. Because the marine aerosols that showed a depletion of C2 were collected under the overcast and/or foggy conditions, we suggest that a photochemical decomposition of oxalic acid may have occurred in aqueous phase of aerosols over the Arctic Ocean via the photo dissociation of oxalate-Fe (III complex. We also determined stable carbon isotopic compositions (δ13C of bulk aerosol carbon and individual diacids. The δ13C of bulk aerosols showed −26.5‰ (range: −29.7 to −24.7‰, suggesting that marine aerosol carbon is derived

  19. 210Po/210Pb Activity Ratios as a Possible `Dating Tool' of Ice Cores and Ice-rafted Sediments from the Western Arctic Ocean - Preliminary Results

    Science.gov (United States)

    Krupp, K.; Baskaran, M. M.

    2016-02-01

    We have collected and analyzed a suite of surface snow samples, ice cores, ice-rafted sediments (IRS) and aerosol samples from the Western Arctic for Po-210 and Pb-210 to examine the extent of disequilibrium between this pair to possibly use 210Po/210Pb activity ratio to date different layers of ice cores and time of incorporation of ice-rafted sediments into the sea ice. We have earlier reported that the activity concentrations of 210Pb in IRS vary over an order of magnitude and it is 1-2 orders of magnitude higher than that of the benthic sediments (1-2 dpm/g in benthic sediments compared to 25 to 300 dpm/g in IRS). In this study, we have measured 210Po/210Pb activity ratios in aerosols from the Arctic Ocean to constrain the initial 210Po/210Pb ratio at the time of deposition during precipitation. The 210Po activity concentration in recent snow is compared to surface ice samples. The `age' of IRS incorporation can be calculated as follows: [210Po]measured = [210Po]initial + [210Pb] (1 - exp(-λt)) (1) where λ is the decay constant of 210Po, 138.4 days, and `t' is the in-growth time period. From this equation, `t' can be calculated as follows: t = (-1/λ) [ln (1- ((210Po/210Pb)measured - (210Po/210Pb)initial)] (2) The assumption involved in this approach are: i) there is no preferential uptake of 210Po (highly biogenic - S group); and iii) both 210Po and 210Pb remain as closed system. The calculated age using equation (2) will be discussed and presented.

  20. The Development of a Finite Volume Method for Modeling Sound in Coastal Ocean Environment

    Energy Technology Data Exchange (ETDEWEB)

    Long, Wen; Yang, Zhaoqing; Copping, Andrea E.; Jung, Ki Won; Deng, Zhiqun

    2015-10-28

    : As the rapid growth of marine renewable energy and off-shore wind energy, there have been concerns that the noises generated from construction and operation of the devices may interfere marine animals’ communication. In this research, a underwater sound model is developed to simulate sound prorogation generated by marine-hydrokinetic energy (MHK) devices or offshore wind (OSW) energy platforms. Finite volume and finite difference methods are developed to solve the 3D Helmholtz equation of sound propagation in the coastal environment. For finite volume method, the grid system consists of triangular grids in horizontal plane and sigma-layers in vertical dimension. A 3D sparse matrix solver with complex coefficients is formed for solving the resulting acoustic pressure field. The Complex Shifted Laplacian Preconditioner (CSLP) method is applied to efficiently solve the matrix system iteratively with MPI parallelization using a high performance cluster. The sound model is then coupled with the Finite Volume Community Ocean Model (FVCOM) for simulating sound propagation generated by human activities in a range-dependent setting, such as offshore wind energy platform constructions and tidal stream turbines. As a proof of concept, initial validation of the finite difference solver is presented for two coastal wedge problems. Validation of finite volume method will be reported separately.

  1. Response of bacterioplankton community structure to an artificial gradient of pCO2 in the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    R. Zhang

    2013-06-01

    Full Text Available In order to test the influences of ocean acidification on the ocean pelagic ecosystem, so far the largest CO2 manipulation mesocosm study (European Project on Ocean Acidification, EPOCA was performed in Kings Bay (Kongsfjorden, Spitsbergen. During a 30 day incubation, bacterial diversity was investigated using DNA fingerprinting and clone library analysis of bacterioplankton samples. Terminal restriction fragment length polymorphism (T-RFLP analysis of the PCR amplicons of the 16S rRNA genes revealed that general bacterial diversity, taxonomic richness and community structure were influenced by the variation of productivity during the time of incubation, but not the degree of ocean acidification. A BIOENV analysis suggested a complex control of bacterial community structure by various biological and chemical environmental parameters. The maximum apparent diversity of bacterioplankton (i.e., the number of T-RFs in high and low pCO2 treatments differed significantly. A negative relationship between the relative abundance of Bacteroidetes and pCO2 levels was observed for samples at the end of the experiment by the combination of T-RFLP and clone library analysis. Our study suggests that ocean acidification affects the development of bacterial assemblages and potentially impacts the ecological function of the bacterioplankton in the marine ecosystem.

  2. Response of bacterioplankton community structure to an artificial gradient of pCO2 in the Arctic Ocean

    Science.gov (United States)

    Zhang, R.; Xia, X.; Lau, S. C. K.; Motegi, C.; Weinbauer, M. G.; Jiao, N.

    2013-06-01

    In order to test the influences of ocean acidification on the ocean pelagic ecosystem, so far the largest CO2 manipulation mesocosm study (European Project on Ocean Acidification, EPOCA) was performed in Kings Bay (Kongsfjorden), Spitsbergen. During a 30 day incubation, bacterial diversity was investigated using DNA fingerprinting and clone library analysis of bacterioplankton samples. Terminal restriction fragment length polymorphism (T-RFLP) analysis of the PCR amplicons of the 16S rRNA genes revealed that general bacterial diversity, taxonomic richness and community structure were influenced by the variation of productivity during the time of incubation, but not the degree of ocean acidification. A BIOENV analysis suggested a complex control of bacterial community structure by various biological and chemical environmental parameters. The maximum apparent diversity of bacterioplankton (i.e., the number of T-RFs) in high and low pCO2 treatments differed significantly. A negative relationship between the relative abundance of Bacteroidetes and pCO2 levels was observed for samples at the end of the experiment by the combination of T-RFLP and clone library analysis. Our study suggests that ocean acidification affects the development of bacterial assemblages and potentially impacts the ecological function of the bacterioplankton in the marine ecosystem.

  3. Sea ice contribution to the air-sea CO(2) exchange in the Arctic and Southern Oceans

    DEFF Research Database (Denmark)

    Rysgaard...[], Søren; Bendtsen, Jørgen; Delille, B.

    2011-01-01

    Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO(2) and the subsequent effect on air-sea CO(2) exchange have received little attention. We review the mechanisms by which sea ice directly and indirectly controls the air......-sea CO(2) exchange and use recent measurements of inorganic carbon compounds in bulk sea ice to estimate that oceanic CO(2) uptake during the seasonal cycle of sea-ice growth and decay in ice-covered oceanic regions equals almost half of the net atmospheric CO(2) uptake in ice-free polar seas. This sea......-sea CO(2) exchange during winter, and (3) release of CO(2)-depleted melt water with excess total alkalinity during sea-ice decay and (4) biological CO(2) drawdown during primary production in sea ice and surface oceanic waters....

  4. The Coastal Ocean Prediction Systems program: Understanding and managing our coastal ocean. Volume 2: Overview and invited papers

    Energy Technology Data Exchange (ETDEWEB)

    1990-05-15

    This document is a compilation of summaries of papers presented at the Coastal Ocean Prediction Systems workshop. Topics include; marine forecasting, regulatory agencies and regulations, research and application models, research and operational observing, oceanic and atmospheric data assimilation, and coastal physical processes.

  5. Temperature, salinity and transmissivity data from the Alpha Helix in the Arctic Ocean, 2000 - 2004 (NODC Accession 0059005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is calibrated CTD downcast data from five Alpha Helix cruises: HX235, 8/1/2000 - 9/30/2000 HX250, 9/1/2001 - 9/30/2001 HX260, 6/1/2002 - 6/30/2002 HX274,...

  6. Coupling Geophysical, Geotechnical and Stratigraphic Data to Interpret the Genesis of Mega-Scale-Glacial-Lineations on the Yermak Plateau, Arctic Ocean

    Science.gov (United States)

    O'Regan, M. A.; Jakobsson, M.; Kirchner, N.; Dowdeswell, J. A.; Hogan, K.

    2010-12-01

    The recent collection and analysis of multi-beam bathymetry data has revealed Mega-Scale Glacial Lineations (MSGL) in up to 600 m present water depth on the Yermak Plateau (Dowdeswell et al., 2010; Jakobsson et al., 2010). This evidence for large-scale ice grounding in the region supports previous interpretations from side-scan sonar, high-resolution subbottom and multi-channel seismic data. Detailed integration with regional subbottom data illustrates that the formation of the MSGL occurred in the late Quaternary, around MIS6. This event is distinct from a middle Quaternary ice grounding in the same region, that was first recognized by the transition into heavily overconsolidated sediments at ~20 mbsf at Ocean Drilling Program Site 910. While the middle Quaternary ice grounding left an easily recognizable imprint on the geotechnical properties of the sediments, the imprint from the late Quaternary event is far subtler, and not formerly recognized by analysis of sediments from Site 910. Furthermore, stratigraphic information indicates that neither event was associated with significant erosion, implying that the observed stress state of the sediments arose from ice-loading. Coupled with the orientation of the late Quaternary MSGL, the available evidence argues against an active ice-stream being responsible for their formation, and that they were more likely formed by a very large tabular iceberg traversing the ridge. This lends considerable support to the argument that MSGL-like features are not exclusively associated with fast flowing ice-streams. References Jakobsson, M., et al., An Arctic Ocean iceshelf during MIS 6 constrained by new geophysical and geological data. Quaternary Science Reviews (2010), doi:10.1016/j.quascirev.2010.03.015. Dowdeswell, J. A., et al., High-resolution geophysical observations of the Yermak Plateau and northern Svalbard margin: implications for ice-sheet grounding and deep-keeled icebergs. Quaternary Science Reviews (2010), doi:10

  7. Contemporary Arctic Sea Level

    Science.gov (United States)

    Cazenave, A. A.

    2017-12-01

    During recent decades, the Arctic region has warmed at a rate about twice the rest of the globe. Sea ice melting is increasing and the Greenland ice sheet is losing mass at an accelerated rate. Arctic warming, decrease in the sea ice cover and fresh water input to the Arctic ocean may eventually impact the Arctic sea level. In this presentation, we review our current knowledge of contemporary Arctic sea level changes. Until the beginning of the 1990s, Arctic sea level variations were essentially deduced from tide gauges located along the Russian and Norwegian coastlines. Since then, high inclination satellite altimetry missions have allowed measuring sea level over a large portion of the Arctic Ocean (up to 80 degree north). Measuring sea level in the Arctic by satellite altimetry is challenging because the presence of sea ice cover limits the full capacity of this technique. However adapted processing of raw altimetric measurements significantly increases the number of valid data, hence the data coverage, from which regional sea level variations can be extracted. Over the altimetry era, positive trend patterns are observed over the Beaufort Gyre and along the east coast of Greenland, while negative trends are reported along the Siberian shelf. On average over the Arctic region covered by satellite altimetry, the rate of sea level rise since 1992 is slightly less than the global mea sea level rate (of about 3 mm per year). On the other hand, the interannual variability is quite significant. Space gravimetry data from the GRACE mission and ocean reanalyses provide information on the mass and steric contributions to sea level, hence on the sea level budget. Budget studies show that regional sea level trends over the Beaufort Gyre and along the eastern coast of Greenland, are essentially due to salinity changes. However, in terms of regional average, the net steric component contributes little to the observed sea level trend. The sea level budget in the Arctic

  8. Microbial analysis of Zetaproteobacteria and co-colonizers of iron mats in the Troll Wall Vent Field, Arctic Mid-Ocean Ridge.

    Directory of Open Access Journals (Sweden)

    Jan Vander Roost

    Full Text Available Over the last decade it has become increasingly clear that Zetaproteobacteria are widespread in hydrothermal systems and that they contribute to the biogeochemical cycling of iron in these environments. However, how chemical factors control the distribution of Zetaproteobacteria and their co-occurring taxa remains elusive. Here we analysed iron mats from the Troll Wall Vent Field (TWVF located at the Arctic Mid-Ocean Ridge (AMOR in the Norwegian-Greenland Sea. The samples were taken at increasing distances from high-temperature venting chimneys towards areas with ultraslow low-temperature venting, encompassing a large variety in geochemical settings. Electron microscopy revealed the presence of biogenic iron stalks in all samples. Using 16S rRNA gene sequence profiling we found that relative abundances of Zetaproteobacteria in the iron mats varied from 0.2 to 37.9%. Biogeographic analyses of Zetaproteobacteria, using the ZetaHunter software, revealed the presence of ZetaOtus 1, 2 and 9, supporting the view that they are cosmopolitan. Relative abundances of co-occurring taxa, including Thaumarchaeota, Euryarchaeota and Proteobacteria, also varied substantially. From our results, combined with results from previous microbiological and geochemical analyses of the TWVF, we infer that the distribution of Zetaproteobacteria is connected to fluid-flow patterns and, ultimately, variations in chemical energy landscapes. Moreover, we provide evidence for iron-oxidizing members of Gallionellaceae being widespread in TWVF iron mats, albeit at low relative abundances.

  9. Effects of sea-ice light attenuation and CDOM absorption in the water below the Eurasian sector of central Arctic Ocean (> 880N)

    DEFF Research Database (Denmark)

    Lund-Hansen, Lars Chresten; Markager, Stiig; Hancke, Kasper

    2015-01-01

    This is a study of the optical, physical and biological parameters of sea ice and the water below it at stations (n=25) in the central (>88°N) Eurasian sector of the Arctic Ocean during the summer 2012 record low sea-ice minimum extent. Results show that photosynthetically active radiation (PAR......) transmittance of the ice was low (0.09) and apparently related to a high degree of backscattering by air-filled brine channels left by brine draining. The under-ice PAR was also low (8.4±4.5 SD µmol photons m−2 s−1) and partly related to the low transmittance. There were no significant differences in multi......-year and first-year PAR transmittances. In spite of this low under-ice PAR, only 3% of the transmitted PAR through the ice was absorbed by phytoplankton in the water. On average, chlorophyll-a concentrations were low (0.34±0.69 SD mg chl-a m−3) in the water compared to the high (a375=0.52 m−1) coloured dissolved...

  10. Operation of a Hovercraft Scientific Platform Over Sea Ice in the Arctic Ocean Transpolar Drift (81 - 85N): The FRAM-2012 Experience

    Science.gov (United States)

    Hall, J. K.; Kristoffersen, Y.

    2013-12-01

    We have tested the feasibility of hovercraft travel through predominantly first year ice of the Transpolar Drift between 81°N - 85°N north of Svalbard. With 2-9 ridges per kilometer, our hovercraft (Griffon TD2000 Mark II), with an effective hover height of about 0.5 m, had to travel a distance 1.3 times the great circle distance between the point of origin and the final destination. Instantaneous speeds were mostly 5-7 knots. Two weeks later icebreaker Oden completed the same transit under conditions with no significant pressure in the ice at a speed mostly 1 knot higher than the hovercraft and travelled 1.2 times the great circle distance. The hovercraft spent 25 days monitoring micro-earthquake activity of the Arctic Mid-Ocean Ridge at a section of the spreading center where no seismicity has been recorded by the global seismograph network. More than ten small earthquake events per day were recorded. Visibility appears to be the most critical factor to hovercraft travel in polar pack ice. Improved control of hovercraft motion would substantially increase the potential usefulness of hovercraft in the sea ice environment. University of Bergen graduate student Gaute Hope emplacing one of the hydrophones in the triangular array used to locate small earthquakes over the Gakkel Ridge rift valley around 85N during FRAM-2012. The research hovercraft R/H SABVABAA is in the background.

  11. White Arctic vs. Blue Arctic: Making Choices

    Science.gov (United States)

    Pfirman, S. L.; Newton, R.; Schlosser, P.; Pomerance, R.; Tremblay, B.; Murray, M. S.; Gerrard, M.

    2015-12-01

    As the Arctic warms and shifts from icy white to watery blue and resource-rich, tension is arising between the desire to restore and sustain an ice-covered Arctic and stakeholder communities that hope to benefit from an open Arctic Ocean. If emissions of greenhouse gases to the atmosphere continue on their present trend, most of the summer sea ice cover is projected to be gone by mid-century, i.e., by the time that few if any interventions could be in place to restore it. There are many local as well as global reasons for ice restoration, including for example, preserving the Arctic's reflectivity, sustaining critical habitat, and maintaining cultural traditions. However, due to challenges in implementing interventions, it may take decades before summer sea ice would begin to return. This means that future generations would be faced with bringing sea ice back into regions where they have not experienced it before. While there is likely to be interest in taking action to restore ice for the local, regional, and global services it provides, there is also interest in the economic advancement that open access brings. Dealing with these emerging issues and new combinations of stakeholders needs new approaches - yet environmental change in the Arctic is proceeding quickly and will force the issues sooner rather than later. In this contribution we examine challenges, opportunities, and responsibilities related to exploring options for restoring Arctic sea ice and potential pathways for their implementation. Negotiating responses involves international strategic considerations including security and governance, meaning that along with local communities, state decision-makers, and commercial interests, national governments will have to play central roles. While these issues are currently playing out in the Arctic, similar tensions are also emerging in other regions.

  12. Surface area and the seabed area, volume, depth, slope, and topographic variation for the world's seas, oceans, and countries.

    Science.gov (United States)

    Costello, Mark John; Cheung, Alan; De Hauwere, Nathalie

    2010-12-01

    Depth and topography directly and indirectly influence most ocean environmental conditions, including light penetration and photosynthesis, sedimentation, current movements and stratification, and thus temperature and oxygen gradients. These parameters are thus likely to influence species distribution patterns and productivity in the oceans. They may be considered the foundation for any standardized classification of ocean ecosystems and important correlates of metrics of biodiversity (e.g., species richness and composition, fisheries). While statistics on ocean depth and topography are often quoted, how they were derived is rarely cited, and unless calculated using the same spatial resolution the resulting statistics will not be strictly comparable. We provide such statistics using the best available resolution (1-min) global bathymetry, and open source digital maps of the world's seas and oceans and countries' Exclusive Economic Zones, using a standardized methodology. We created a terrain map and calculated sea surface and seabed area, volume, and mean, standard deviation, maximum, and minimum, of both depth and slope. All the source data and our database are freely available online. We found that although the ocean is flat, and up to 71% of the area has a ocean volume exceeds 1.3 billion km(3) (or 1.3 sextillion liters), and sea surface and seabed areas over 354 million km(2). We propose the coefficient of variation of slope as an index of topographic heterogeneity. Future studies may improve on this database, for example by using a more detailed bathymetry, and in situ measured data. The database could be used to classify ocean features, such as abyssal plains, ridges, and slopes, and thus provide the basis for a standards based classification of ocean topography.

  13. Low pCO2 under sea-ice melt in the Canada Basin of the western Arctic Ocean

    Science.gov (United States)

    Kosugi, Naohiro; Sasano, Daisuke; Ishii, Masao; Nishino, Shigeto; Uchida, Hiroshi; Yoshikawa-Inoue, Hisayuki

    2017-12-01

    In September 2013, we observed an expanse of surface water with low CO2 partial pressure (pCO2sea) (Ocean. The large undersaturation of CO2 in this region was the result of massive primary production after the sea-ice retreat in June and July. In the surface of the Canada Basin, salinity was low ( 20 µmol kg-1) in the subsurface low pCO2sea layer in the Canada Basin indicated significant net primary production undersea and/or in preformed condition. If these low pCO2sea layers surface by wind mixing, they will act as additional CO2 sinks; however, this is unlikely because intensification of stratification by sea-ice melt inhibits mixing across the halocline.

  14. Arctic Newcomers

    DEFF Research Database (Denmark)

    Tonami, Aki

    2013-01-01

    Interest in the Arctic region and its economic potential in Japan, South Korea and Singapore was slow to develop but is now rapidly growing. All three countries have in recent years accelerated their engagement with Arctic states, laying the institutional frameworks needed to better understand...... and influence policies relating to the Arctic. But each country’s approach is quite different, writes Aki Tonami....

  15. Seismic velocities within the sedimentary succession of the Canada Basin and southern Alpha-Mendeleev Ridge, Arctic Ocean: evidence for accelerated porosity reduction?

    Science.gov (United States)

    Shimeld, John; Li, Qingmou; Chian, Deping; Lebedeva-Ivanova, Nina; Jackson, Ruth; Mosher, David; Hutchinson, Deborah R.

    2016-01-01

    The Canada Basin and the southern Alpha-Mendeleev ridge complex underlie a significant proportion of the Arctic Ocean, but the geology of this undrilled and mostly ice-covered frontier is poorly known. New information is encoded in seismic wide-angle reflections and refractions recorded with expendable sonobuoys between 2007 and 2011. Velocity–depth samples within the sedimentary succession are extracted from published analyses for 142 of these records obtained at irregularly spaced stations across an area of 1.9E + 06 km2. The samples are modelled at regional, subregional and station-specific scales using an exponential function of inverse velocity versus depth with regionally representative parameters determined through numerical regression. With this approach, smooth, non-oscillatory velocity–depth profiles can be generated for any desired location in the study area, even where the measurement density is low. Practical application is demonstrated with a map of sedimentary thickness, derived from seismic reflection horizons interpreted in the time domain and depth converted using the velocity–depth profiles for each seismic trace. A thickness of 12–13 km is present beneath both the upper Mackenzie fan and the middle slope off of Alaska, but the sedimentary prism thins more gradually outboard of the latter region. Mapping of the observed-to-predicted velocities reveals coherent geospatial trends associated with five subregions: the Mackenzie fan; the continental slopes beyond the Mackenzie fan; the abyssal plain; the southwestern Canada Basin; and, the Alpha-Mendeleev magnetic domain. Comparison of the subregional velocity–depth models with published borehole data, and interpretation of the station-specific best-fitting model parameters, suggests that sandstone is not a predominant lithology in any of the five subregions. However, the bulk sand-to-shale ratio likely increases towards the Mackenzie fan, and the model for this subregion compares

  16. Changes in summer sea ice, albedo, and portioning of surface solar radiation in the Pacific sector of Arctic Ocean during 1982-2009

    Science.gov (United States)

    Lei, Ruibo; Tian-Kunze, Xiangshan; Leppäranta, Matti; Wang, Jia; Kaleschke, Lars; Zhang, Zhanhai

    2016-08-01

    SSM/I sea ice concentration and CLARA black-sky composite albedo were used to estimate sea ice albedo in the region 70°N-82°N, 130°W-180°W. The long-term trends and seasonal evolutions of ice concentration, composite albedo, and ice albedo were then obtained. In July-August 1982-2009, the linear trend of the composite albedo and the ice albedo was -0.069 and -0.046 units per decade, respectively. During 1 June to 19 August, melting of sea ice resulted in an increase of solar heat input to the ice-ocean system by 282 MJ·m-2 from 1982 to 2009. However, because of the counter-balancing effects of the loss of sea ice area and the enhanced ice surface melting, the trend of solar heat input to the ice was insignificant. The summer evolution of ice albedo matched the ice surface melting and ponding well at basin scale. The ice albedo showed a large difference between the multiyear and first-year ice because the latter melted completely by the end of a melt season. At the SHEBA geolocations, a distinct change in the ice albedo has occurred since 2007, because most of the multiyear ice has been replaced by first-year ice. A positive polarity in the Arctic Dipole Anomaly could be partly responsible for the rapid loss of summer ice within the study region in the recent years by bringing warmer air masses from the south and advecting more ice toward the north. Both these effects would enhance ice-albedo feedback.

  17. Does Arctic sea ice reduction foster shelf-basin exchange?

    Science.gov (United States)

    Ivanov, Vladimir; Watanabe, Eiji

    2013-12-01

    The recent shift in Arctic ice conditions from prevailing multi-year ice to first-year ice will presumably intensify fall-winter sea ice freezing and the associated salt flux to the underlying water column. Here, we conduct a dual modeling study whose results suggest that the predicted catastrophic consequences for the global thermohaline circulation (THC), as a result of the disappearance of Arctic sea ice, may not necessarily occur. In a warmer climate, the substantial fraction of dense water feeding the Greenland-Scotland overflow may form on Arctic shelves and cascade to the deep basin, thus replenishing dense water, which currently forms through open ocean convection in the sub-Arctic seas. We have used a simplified model for estimating how increased ice production influences shelf-basin exchange associated with dense water cascading. We have carried out case studies in two regions of the Arctic Ocean where cascading was observed in the past. The baseline range of buoyancy-forcing derived from the columnar ice formation was calculated as part of a 30-year experiment of the pan-Arctic coupled ice-ocean general circulation model (GCM). The GCM results indicate that mechanical sea ice divergence associated with lateral advection accounts for a significant part of the interannual variations in sea ice thermal production in the coastal polynya regions. This forcing was then rectified by taking into account sub-grid processes and used in a regional model with analytically prescribed bottom topography and vertical stratification in order to examine specific cascading conditions in the Pacific and Atlantic sectors of the Arctic Ocean. Our results demonstrate that the consequences of enhanced ice formation depend on geographical location and shelf-basin bathymetry. In the Pacific sector, strong density stratification in slope waters impedes noticeable deepening of shelf-origin water, even for the strongest forcing applied. In the Atlantic sector, a 1.5x increase of

  18. Fungi Sailing the Arctic Ocean: Speciose Communities in North Atlantic Driftwood as Revealed by High-Throughput Amplicon Sequencing.

    Science.gov (United States)

    Rämä, Teppo; Davey, Marie L; Nordén, Jenni; Halvorsen, Rune; Blaalid, Rakel; Mathiassen, Geir H; Alsos, Inger G; Kauserud, Håvard

    2016-08-01

    High amounts of driftwood sail across the oceans and provide habitat for organisms tolerating the rough and saline environment. Fungi have adapted to the extremely cold and saline conditions which driftwood faces in the high north. For the first time, we applied high-throughput sequencing to fungi residing in driftwood to reveal their taxonomic richness, community composition, and ecology in the North Atlantic. Using pyrosequencing of ITS2 amplicons obtained from 49 marine logs, we found 807 fungal operational taxonomic units (OTUs) based on clustering at 97 % sequence similarity cut-off level. The phylum Ascomycota comprised 74 % of the OTUs and 20 % belonged to Basidiomycota. The richness of basidiomycetes decreased with prolonged submersion in the sea, supporting the general view of ascomycetes being more extremotolerant. However, more than one fourth of the fungal OTUs remained unassigned to any fungal class, emphasising the need for better DNA reference data from the marine habitat. Different fungal communities were detected in coniferous and deciduous logs. Our results highlight that driftwood hosts a considerably higher fungal diversity than currently known. The driftwood fungal community is not a terrestrial relic but a speciose assemblage of fungi adapted to the stressful marine environment and different kinds of wooden substrates found in it.

  19. The Sensitivity of Arctic Ozone Loss to Polar Stratospheric Cloud Volume and Chlorine and Bromine Loading in a Chemistry and Transport Model

    Science.gov (United States)

    Douglass, A. R.; Stolarski, R. S.; Strahan, S. E.; Polansky, B. C.

    2006-01-01

    The sensitivity of Arctic ozone loss to polar stratospheric cloud volume (V(sub PSC)) and chlorine and bromine loading is explored using chemistry and transport models (CTMs). A simulation using multi-decadal output from a general circulation model (GCM) in the Goddard Space Flight Center (GSFC) CTM complements one recycling a single year s GCM output in the Global Modeling Initiative (GMI) CTM. Winter polar ozone loss in the GSFC CTM depends on equivalent effective stratospheric chlorine (EESC) and polar vortex characteristics (temperatures, descent, isolation, polar stratospheric cloud amount). Polar ozone loss in the GMI CTM depends only on changes in EESC as the dynamics repeat annually. The GSFC CTM simulation reproduces a linear relationship between ozone loss and Vpsc derived from observations for 1992 - 2003 which holds for EESC within approx.85% of its maximum (approx.1990 - 2020). The GMI simulation shows that ozone loss varies linearly with EESC for constant, high V(sub PSC).

  20. Marine Corps Equities in the Arctic

    Science.gov (United States)

    2013-04-18

    reduces the shipping time from Yokohama, Japan, to Hamburg , Germany, by 11 days as compared to the Suez Canal. Ships average approximately a 20...areas within the Arctic Circle. 10 Warming ocean water is causing fisheries to shift north as well. Fish populations usually found in the...people live in the Arctic region. Commercial fishing fleets are following these populations. 29 Russia holds the majority of the Arctic population

  1. Zooplankton biomass (displacement volume) data collected in Indian Ocean, Southern Pacific and Southern Atlantic Ocean during Discovery Investigations project from 1931-01-02 to 1951-10-18 by Discovery II, data were acquired from the NMFS-COPEPOD database (NODC Accession 0071064)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton biomass (displacement volume) data collected in Indian Ocean, Southern Pacific and Southern Atlantic Ocean during Discovery Investigations project from...

  2. Numerical Methods in Atmospheric and Oceanic Modelling: The Andre J. Robert Memorial Volume

    Science.gov (United States)

    Rosmond, Tom

    Most people, even including some in the scientific community, do not realize how much the weather forecasts they use to guide the activities of their daily lives depend on very complex mathematics and numerical methods that are the basis of modern numerical weather prediction (NWP). André Robert (1929-1993), to whom Numerical Methods in Atmospheric and Oceanic Modelling is dedicated, had a career that contributed greatly to the growth of NWP and the role that the atmospheric computer models of NWP play in our society. There are probably no NWP models running anywhere in the world today that do not use numerical methods introduced by Robert, and those of us who work with and use these models everyday are indebted to him.The first two chapters of the volume are chronicles of Robert's life and career. The first is a 1987 interview by Harold Ritchie, one of Robert's many proteges and colleagues at the Canadian Atmospheric Environment Service. The interview traces Robert's life from his birth in New York to French Canadian parents, to his emigration to Quebec at an early age, his education and early employment, and his rise in stature as one of the preeminent research meteorologists of our time. An amusing anecdote he relates is his impression of weather forecasts while he was considering his first job as a meteorologist in the early 1950s. A newspaper of the time placed the weather forecast and daily horoscope side by side, and Robert regarded each to have a similar scientific basis. Thankfully he soon realized there was a difference between the two, and his subsequent career certainly confirmed the distinction.

  3. A quantitative assessment of Arctic shipping in 2010–2014

    KAUST Repository

    Eguíluz, Victor M.

    2016-08-01

    Rapid loss of sea ice is opening up the Arctic Ocean to shipping, a practice that is forecasted to increase rapidly by 2050 when many models predict that the Arctic Ocean will largely be free of ice toward the end of summer. These forecasts carry considerable uncertainty because Arctic shipping was previously considered too sparse to allow for adequate validation. Here, we provide quantitative evidence that the extent of Arctic shipping in the period 2011–2014 is already significant and that it is concentrated (i) in the Norwegian and Barents Seas, and (ii) predominantly accessed via the Northeast and Northwest Passages. Thick ice along the forecasted direct trans-Arctic route was still present in 2014, preventing transit. Although Arctic shipping remains constrained by the extent of ice coverage, during every September, this coverage is at a minimum, allowing the highest levels of shipping activity. Access to Arctic resources, particularly fisheries, is the most important driver of Arctic shipping thus far.

  4. Arctic Landfast Sea Ice 1953-1998

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The files in this data set contain landfast sea ice data (monthly means) gathered from both Russian Arctic and Antarctic Research Institute (AARI) and Canadian Ice...

  5. Proceedings of oceans '91

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    This volume contains the proceedings of the Oceans '91 Conference. Topics addressed include: ocean energy conversion, marine communications and navigation, ocean wave energy conversion, environmental modeling, global climate change, ocean minerals technology, oil spill technology, and submersible vehicles

  6. Humidification of the Arctic: Effects of more open ocean water on land temperatures and tundra productivity along continental and maritime bioclimate transects

    Science.gov (United States)

    Bhatt, U. S.; Walker, D. A.; Raynolds, M. K.; Epstein, H. E.

    2017-12-01

    Amplified Arctic warming linked to declining sea-ice extent led to generally enhanced productivity of the tundra biome during the period 1982-2008. After about 2002, coinciding with a recent precipitous decline in sea ice, large areas of the Arctic began showing reversals of previous positive productivity trends. To better understand these recent vegetation productivity declines and whether they are associated with differences in a general humidification of portions of the Arctic, we focus analysis on two transects with ground information: the more continental North America Arctic Transect (NAAT) and the more maritime Eurasia Arctic Transect (EAT). We compare ground information with satellite-derived trends in open water, summer terrestrial temperatures, and vegetation greenness and changes in continentality of the two transects, as indicated by the differences in the annual maximum and minimum mean monthly temperatures. Areas adjacent to perennial sea ice along in the northern parts of the NAAT exhibit climates with positive trends in summer warmth, but negative greening trends, possibly due to soil drying. Southern parts of the NAAT in the vicinity of more open water show positive greenness trends. Along the EAT, cooling midsummer conditions and reduced greenness appear to be caused by cloudier conditions, and possibly later snow melt during the period of maximum potential photosynthesis. Ground-based environmental and vegetation data indicate that biomass, particularly moss biomass is much greater along the more maritime EAT, indicating a buffering effect of the