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  • PANGAEA  (6)
  • Alfred-Wegener-Institut für Polar- und Meeresforschung  (1)
  • Copernicus  (1)
Collection
Keywords
  • 1
    Publication Date: 2023-03-10
    Keywords: BATS15m; Cerium, dissolved; CTD/Rosette; CTD-RO; DEPTH, water; Dysprosium, dissolved; Erbium, dissolved; Europium, dissolved; Gadolinium, dissolved; GEOTRACES; Global marine biogeochemical cycles of trace elements and their isotopes; Holmium, dissolved; Lanthanum, dissolved; Lutetium, dissolved; Neodymium, dissolved; Praseodymium, dissolved; Samarium, dissolved; South Atlantic Ocean; Terbium, dissolved; Thulium, dissolved; Ytterbium, dissolved; Yttrium, dissolved
    Type: Dataset
    Format: text/tab-separated-values, 225 data points
    Location Call Number Expected Availability
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  • 2
    Publication Date: 2023-03-10
    Keywords: BATS2000m; Cerium, dissolved; CTD/Rosette; CTD-RO; DEPTH, water; Dysprosium, dissolved; Erbium, dissolved; Europium, dissolved; Gadolinium, dissolved; GEOTRACES; Global marine biogeochemical cycles of trace elements and their isotopes; Holmium, dissolved; Lanthanum, dissolved; Lutetium, dissolved; Neodymium, dissolved; Praseodymium, dissolved; Samarium, dissolved; South Atlantic Ocean; Terbium, dissolved; Thulium, dissolved; Ytterbium, dissolved; Yttrium, dissolved
    Type: Dataset
    Format: text/tab-separated-values, 195 data points
    Location Call Number Expected Availability
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  • 3
    Publication Date: 2023-02-24
    Keywords: Classification; Conductivity; CTD/Rosette; CTD-RO; Density, sigma500; Density, sigma-theta (0); DEPTH, water; Elevation of event; Event label; GEOTRACES; Global marine biogeochemical cycles of trace elements and their isotopes; Laptev Sea; Latitude of event; Longitude of event; Neodymium, dissolved; Neodymium-143/Neodymium-144 ratio; Neodymium-143/Neodymium-144 ratio, standard deviation; Pressure, water; Salinity; Sample ID; TDXXI-19; TDXXII-17; Temperature, water; Temperature, water, potential; ε-Neodymium; ε-Neodymium, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 25 data points
    Location Call Number Expected Availability
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  • 4
    facet.materialart.
    Unknown
    PANGAEA
    In:  Supplement to: Laukert, Georgi; Frank, Martin; Bauch, Dorothea; Hathorne, Ed C; Rabe, Benjamin; von Appen, Wilken-Jon; Wegner, Carolyn; Zieringer, Moritz; Kassens, Heidemarie (2017): Ocean circulation and freshwater pathways in the Arctic Mediterranean based on a combined Nd isotope, REE and oxygen isotope section across Fram Strait. Geochimica et Cosmochimica Acta, 202, 285-309, https://doi.org/10.1016/j.gca.2016.12.028
    Publication Date: 2023-04-03
    Description: The water masses passing the Fram Strait are mainly responsible for the exchange of heat and freshwater between the Nordic Seas and the Arctic Ocean (the Arctic Mediterranean, AM). Disentangling their exact sources, distribution and mixing, however, is complex. This work provides new insights based on a detailed geochemical tracer inventory including dissolved Nd isotope (e-Nd), rare earth element (REE) and stable oxygen isotope (d18O) data along a full water depth section across Fram Strait. We find that Nd isotope and REE distributions in the open AM primarily reflect lateral advection of water masses and their mixing. Seawater-particle interactions exert important control only above the shelf regions, as observed above the NE Greenland Shelf. Advection of northward flowing warm Atlantic Water (AW) is clearly reflected by an e-Nd signature of -11.7 and a Nd concentration ([Nd]) of 16 pmol/kg in the upper ~500 m of the eastern and central Fram Strait. Freshening and cooling of the AW on its way trough the AM are accompanied by a continuous change towards more radiogenic e-Nd signatures (e.g. -10.4 of dense Arctic Atlantic Water). This mainly reflects mixing with intermediate waters but also admixture of dense Kara Sea waters and Pacific-derived waters. The more radiogenic e-Nd signatures of the intermediate and deep waters (reaching -9.5) are mainly acquired in the SW Nordic Seas through exchange with basaltic formations of Iceland and CE Greenland. Inputs of Nd from Svalbard are not observed and surface waters and Nd on the Svalbard shelf originate from the Barents Sea. Shallow southward flowing Arctic-derived waters (〈200 m) form the core of the East Greenland Current above the Greenland slope and can be traced by their relatively radiogenic e-Nd (reaching -8.8) and elevated [Nd] (21-29 pmol/kg). These properties are used together with d18O and standard hydrographic tracers to define the proportions of Pacific-derived (〈~30% based on Nd isotopes) and Atlantic-derived waters, as well as of river waters (〈~8%). Shallow waters (〈150 m) on the NE Greenland Shelf share some characteristics of Arctic-derived waters, but exhibit less radiogenic epsilon-Nd values (reaching -12.4) and higher [Nd] (up to 38 pmol/kg) in the upper ~100 m. This suggests local addition of Greenland freshwater of up to ~6%. In addition to these observations, this study shows that the pronounced gradients in epsilon-Nd signatures and REE characteristics in the upper water column provide a reliable basis for assessments of shallow hydrological changes within the AM.
    Keywords: GEOTRACES; Global marine biogeochemical cycles of trace elements and their isotopes
    Type: Dataset
    Format: application/zip, 4 datasets
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  • 5
    Publication Date: 2024-06-26
    Keywords: ARK-XXVII/1; Attenuation, optical beam transmission; Calculated; Calculated, PAAS-normalized (McLennan, 2001); Cerium, dissolved; Cerium anomaly; Classification; Conductivity; CTD/Rosette; CTD-RO; Date/Time of event; Density, sigma1500; Density, sigma2500; Density, sigma500; Density, sigma-theta (0); DEPTH, water; Dysprosium, dissolved; Elevation of event; Erbium, dissolved; Europium, dissolved; Event label; Fluorometer; Gadolinium, dissolved; GEOTRACES; Global marine biogeochemical cycles of trace elements and their isotopes; Heavy rare-earth elements/light rare-earth elements ratio; Holmium, dissolved; Isotope dilution; Lanthanum, dissolved; Latitude of event; Longitude of event; Lutetium, dissolved; Middle rare-earth elements anomaly; Neodymium, dissolved; Neodymium-143/Neodymium-144 ratio; Neodymium-143/Neodymium-144 ratio, standard deviation; North Greenland Sea; Oxygen; Oxygen saturation; Polarstern; Praseodymium, dissolved; Pressure, water; PS80; PS80/013-1; PS80/016-1; PS80/019-1; PS80/026-1; PS80/050-1; PS80/055-1; PS80/068-1; PS80/086-1; PS80/092-1; PS80/097-1; PS80/106-1; PS80/110-1; PS80/113-1; PS80/118-1; PS80/121-1; PS80/124-1; PS80/126-1; PS80/130-1; PS80/132-1; PS80/134-1; Salinity; Samarium, dissolved; Sample ID; Temperature, water; Temperature, water, potential; Terbium, dissolved; Thulium, dissolved; Ytterbium, dissolved; Yttrium, dissolved; ε-Neodymium; ε-Neodymium, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 3962 data points
    Location Call Number Expected Availability
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  • 6
    facet.materialart.
    Unknown
    PANGAEA
    In:  Supplement to: Bauch, Dorothea; Dmitrenko, Igor; Wegner, Carolyn; Hölemann, Jens A; Kirillov, Sergey A; Timokhov, Leonid; Kassens, Heidemarie (2009): Exchange of Laptev Sea and Arctic Ocean halocline waters in response to atmospheric forcing. Journal of Geophysical Research: Oceans, 114, C05008, https://doi.org/10.1029/2008JC005062
    Publication Date: 2024-07-01
    Description: Combined d18O/salinity data reveal a distinctive water mass generated during winter sea ice formation which is found predominantly in the coastal polynya region of the southern Laptev Sea. Export of the brine-enriched bottom water shows interannual variability in correlation with atmospheric conditions. Summer anticyclonic circulation is favoring an offshore transport of river water at the surface as well as a pronounced signal of brine-enriched waters at about 50 m water depth at the shelf break. Summer cyclonic atmospheric circulation favors onshore or an eastward, alongshore water transport, and at the shelf break the river water fraction is reduced and the pronounced brine signal is missing, while on the middle Laptev Sea shelf, brine-enriched waters are found in high proportions. Residence times of bottom and subsurface waters on the shelf may thereby vary considerably: an export of shelf waters to the Arctic Ocean halocline might be shut down or strongly reduced during "onshore" cyclonic atmospheric circulation, while with "offshore" anticyclonic atmospheric circulation, brine waters are exported and residence times may be as short as 1 year only.
    Keywords: ARK-XIV/1b; CTD/Rosette; CTD-RO; East Siberian Sea; Giant box corer; GKG; Helicopter; IK03-01-A; IK03-02-A; IK03-03-A; IK03-03-B; IK03-04-A; IK03-05-A; IK03-06-A; IK03-07-A; IK03-08-A; IK03-09-A; IK03-10-A; IK03-11-A; IK03-12-A; IK03-13-A; IK03-14-A; IK03-15-A; IK03-16-A; IK03-17-A; IK03-18-A; IK03-19-A; IK03-20-A; IK03-21-A; IK03-22-A; IK03-23-A; IK93_1; IK93_10; IK93_100; IK93_101; IK93_102; IK93_103; IK93_104; IK93_105; IK93_106; IK93_107; IK93_108; IK93_109; IK93_11; IK93_110; IK93_111; IK93_112; IK93_113; IK93_114; IK93_115; IK93_116; IK93_117; IK93_118; IK93_119; IK93_12; IK93_120; IK93_121; IK93_122; IK93_123; IK93_124; IK93_125; IK93_126; IK93_127; IK93_128; IK93_129; IK93_13; IK93_130; IK93_131; IK93_14; IK93_15; IK93_16; IK93_17; IK93_18; IK93_19; IK93_2; IK93_20; IK93_21; IK93_22; IK93_23; IK93_24; IK93_25; IK93_26; IK93_27; IK93_28; IK93_29; IK93_3; IK93_30; IK93_31; IK93_32; IK93_33; IK93_34; IK93_35; IK93_36; IK93_37; IK93_38; IK93_38a; IK93_39; IK93_4; IK93_40; IK93_41; IK93_42; IK93_43; IK93_44; IK93_45; IK93_45a; IK93_46; IK93_47; IK93_48; IK93_49; IK93_5; IK93_50; IK93_51; IK93_52; IK93_53; IK93_54; IK93_55; IK93_56; IK93_57; IK93_58; IK93_59; IK93_6; IK93_60; IK93_61; IK93_62; IK93_63; IK93_64; IK93_65; IK93_66; IK93_67; IK93_68; IK93_69; IK93_7; IK93_70; IK93_71; IK93_72; IK93_73; IK93_74; IK93_75; IK93_76; IK93_77; IK93_78; IK93_79; IK93_8; IK93_80; IK93_81; IK93_82; IK93_83; IK93_84; IK93_85; IK93_86; IK93_87; IK93_88; IK93_89; IK93_9; IK93_90; IK93_91; IK93_92; IK93_93; IK93_94; IK93_95; IK93_96; IK93_97; IK93_98; IK93_99; Ivan Kireyev; Kapitan Dranitsyn; Kara Sea; KD9501-1; KD9502-1; KD9502-2; KD9502-3; KD9502-4; KD9503-1; KD9504-1; KD9505-1; KD9506-1; KD9507-1; KD9508-1; KD9509-1; KD9510-1; KD9511-1; KD9512-1; KD9513-1; KD9514-1; KD9515-1; KD9516-1; KD9517-1; KD9518-1; KD9519-1; KD9520-1; KD9521-1; KD9522-1; KD9523-1; KD9524-1; KD9525-1; KD9526-1; KD9527-1; KD9528-1; KD9529-1; KD9530-1; KD9531-1; KD9532-1; KD9533-1; KD9534-1; KD9536-1; KD9538-1; KD9540-1; KD9541-1; KD9543-1; KD9545-1; KD9546-1; KD9547-1; KD9548-1; KD9549-1; KD9550-1; KD9551-1; KD9552-1; KD9553-1; KD9554-1; KD9555-1; KD9556-1; KD9557-1; KD9558-1; KD9559-1; KD9560-1; KD9564-1; KD9565-1; KD9566-1; KD9567-1; KD9568-1; KD9569-1; KD9570-1; KD9571-1; KD9573-1; KD9574-1; Laptev Sea; Laptev Sea System; Lena Nordenskøld Station; LN9601-1; LN9602-1; LN9603-1; LN9603A-2; LN9603B-2; LN9604-1; LN9604A-2; LN9604B-2; LN9605-1; LN9605A-1; LN9605B-1; LN9606-1; LN9606A-2; LN9606B-2; LN9608-2; LN9608A-3; LN9608B-2; LN9609-1; LN9609A-2; LN9609B-2; LN9610-1; LN9610A-2; LN9610B-1; LN9611-2; LN9611A-3; LN9611B-3; LN9612-1; LN9613-1; LN9614-1; LN9615-1; LN9616-1; LN9617-1; LN9618-1; LN9619-1; LN9620-1; LN9620A-2; LN9621-1; LN9621A-2; LN9622-1; LN9623-1; LN9623A-2; LN9624-2; LN9624A-1; LN9625-1; LSS; MULT; Multiple investigations; PM9401-1; PM9401-2; PM9401-3; PM9402-1; PM9402-2; PM9402-3; PM9402-4; PM9402-5; PM9402-6; PM9402-7; PM9403-1; PM9403-2; PM9404-1; PM9405-1; PM9405-2; PM9406-1; PM9407-1; PM9407-2; PM9408-1; PM9409-1; PM94100-1; PM9410-1; PM94101-1; PM9410-2; PM9411-1; PM9412-1; PM9413-1; PM9413-10; PM9413-11; PM9413-12; PM9413-13; PM9413-2; PM9413-3; PM9413-4; PM9413-5; PM9413-6; PM9413-7; PM9413-8; PM9413-9; PM9414-1; PM9415-1; PM9415-2; PM9416-1; PM9416-2; PM9417-1; PM9417-10; PM9417-11; PM9417-12; PM9417-13; PM9417-14; PM9417-15; PM9417-16; PM9417-17; PM9417-2; PM9417-3; PM9417-4; PM9417-5; PM9417-6; PM9417-7; PM9417-8; PM9417-9; PM9418-1; PM9418-2; PM9419-1; PM9419-2; PM9419-3; PM9420-1; PM9420-2; PM9421-1; PM9421-2; PM9422-1; PM9423-1; PM9424; PM9424-1; PM9424-10; PM9424-11; PM9424-12; PM9424-13; PM9424-14; PM9424-15; PM9424-16; PM9424-17; PM9424-18; PM9424-2; PM9424-20; PM9424-3; PM9424-4; PM9424-5; PM9424-6; PM9424-7; PM9424-8; PM9424-9; PM9425-1; PM9426-1; PM9426-2; PM9427-1; PM9427-2; PM9428-1; PM9428-2; PM9429-1; PM9429-2; PM9430-1; PM9430-2; PM9431-1; PM9431-2; PM9432-1; PM9432-2; PM9433-1; PM9433-2; PM9434-1; PM9435-1; PM9436-1; PM9436-2; PM9437-1; PM9437-2; PM9437-3; PM9438-1; PM9438-2; PM9439-1; PM9440-1; PM9440-2; PM9441-1; PM9441-2; PM9442-1; PM9442-2; PM9442-3; PM9442-4; PM9442-5; PM9442-6; PM9442-7; PM9442-8; PM9443-1; PM9443-2; PM9444-1; PM9444-2; PM9445-1; PM9445-10; PM9445-11; PM9445-12; PM9445-13; PM9445-14; PM9445-15; PM9445-16; PM9445-17; PM9445-2; PM9445-3; PM9445-4; PM9445-6; PM9445-7; PM9445-8; PM9445-9; PM9446-1; PM9447-1; PM9448-1; PM9449-1; PM9449-2; PM9450-1; PM9451-1; PM9452-1; PM9453-1; PM9454-1; PM9455-1; PM9456-1; PM9457-1; PM9458-1; PM9459-1; PM9460-1; PM9461-1; PM9462-1; PM9462-2; PM9463; PM9463-1; PM9463-10; PM9463-11; PM9463-12; PM9463-13; PM9463-14; PM9463-15; PM9463-16; PM9463-17; PM9463-18; PM9463-2; PM9463-20; PM9463-21; PM9463-22; PM9463-23; PM9463-24; PM9463-25; PM9463-26; PM9463-27; PM9463-28; PM9463-29; PM9463-3; PM9463-30; PM9463-31; PM9463-32; PM9463-33; PM9463-34; PM9463-35; PM9463-36; PM9463-37; PM9463-38; PM9463-39; PM9463-4; PM9463-40; PM9463-41; PM9463-42; PM9463-43; PM9463-5; PM9463-6; PM9463-7; PM9463-8; PM9463-9; PM9465-1; PM9466-1; PM9466-2; PM9466-3; PM9467-1; PM9467-2; PM9468-1; PM9468-2; PM9469-1; PM9469-2; PM9470-1; PM9470-2; PM9471-1; PM9472-1; PM9473-1; PM9474-1; PM9475-1; PM9476-1; PM9477-1; PM9478-1; PM9479-1; PM9480-1; PM9481-1; PM9483-1; PM9484-1; PM9485-1; PM9486-1; PM9487-1; PM9488-1; PM9489-1; PM9490-1; PM9491-1; PM9493-1; PM9493-2; PM9494-1; PM9495-1; PM9496-1; PM9497-1; PM9498-1; PM9499-1; PM94a33-1; PM94a51-10; PM94a51-11; PM94a51-12; PM94a51-13; PM94a51-14; PM94a51-15; PM94a51-16; PM94a51-17; PM94a51-18; PM94a51-2; PM94a51-3; PM94a51-4; PM94a51-5; PM94a51-6; PM94a51-7; PM94a51-8; PM94a51-9; PM94a57-1; PM94K01; PM94K02; PM94K03; PM94K04; PM94K05; PM94K06; PM94K07-1; PM94K08-1; PM94K08-2; PM94K09-1; PM94K09-2; PM94K10-1; PM94K10-2; PM94K11-1; PM94K12; PM94K12-1; PM94K12-11; PM94K12-12; PM94K12-13; PM94K12-14; PM94K12-15; PM94K12-16; PM94K12-17; PM94K12-18; PM94K12-2; PM94K12-20; PM94K12-21; PM94K12-22; PM94K12-23; PM94K12-24; PM94K12-25; PM94K12-26; PM94K12-27; PM94K12-28; PM94K12-29; PM94K12-3; PM94K12-4; PM94K12-5; PM94K12-6; PM94K12-7; PM94K12-8; PM94K12-9; PM94K13; PM94K13-1; PM94K13-10; PM94K13-11; PM94K13-12; PM94K13-13; PM94K13-14; PM94K13-15; PM94K13-16; PM94K13-17; PM94K13-18; PM94K13-2; PM94K13-20; PM94K13-21; PM94K13-22; PM94K13-23; PM94K13-24; PM94K13-25; PM94K13-26; PM94K13-27; PM94K13-28; PM94K13-29; PM94K13-3; PM94K13-30; PM94K13-31; PM94K13-32; PM94K13-33; PM94K13-34; PM94K13-4; PM94K13-5; PM94K13-6; PM94K13-7; PM94K13-8; PM94K13-9; PM94K14-1; PM94K14-2; PM94K14-3; PM94K14-4; PM94K14-5; PM94K15-1; PM94K16-1; Polarstern; Professor Multanovskiy; PS51/078-1; PS51/080-7; PS51/082-1; PS51/083-2; PS51/084-2; PS51/086-1; PS51/087-2; PS51/089-1; PS51/090-1; PS51/091-1; PS51/092-7; PS51/095-3; PS51/096-3; PS51/097-1; PS51/098-3; PS51/099-3; PS51/100-3; PS51/101-1; PS51/102-3; PS51/103-1; PS51/104-7; PS51/110-3; PS51/112-3; PS51/114-2; PS51/116-1; PS51/120-1; PS51/122-1; PS51/125-2; PS51/129-1; PS51/130-1; PS51/131-2; PS51/132-2; PS51/133-2; PS51/134-3; PS51/138-7; PS51/144-5; PS51/145-2; PS51/146-5; PS51/147-2; PS51/148-5; PS51/149-5; PS51/150-5; PS51/151-2; PS51/152-4; PS51/153-2; PS51/154-4; PS51/157-2; PS51/158-2; PS51/159-5; PS51 Transdrift-V; TI99; TI9901-1; TI9902-1; TI9903-1; TI9904-1; TI9905-1; TI9906-1; TI9907-1; TI9908-1; TI9909-1; TI9910-1; TI9911-1; TI9912-1; TI9913-1; TI9914-1; TI9915-1; TI9916-1; TI9917-1; TI9918-1; TI9919-1; TI9920-1; TI9921-1; TI9922-1; TI9923-1; TI9924-1; Transdrift-I; Transdrift-II; Transdrift-III; Transdrift-IV; Transdrift-IX; Transdrift-VI; Transdrift-VII; Transdrift-VIII; Water sample; WS; Yakov Smirnitskiy; YS00_01; YS00_02; YS00_03; YS00_04; YS00_05; YS00_06; YS00_07; YS00_08; YS00_09; YS00_10; YS00_11; YS00_12; YS00_13; YS00_14; YS00_15; YS00_16; YS00_17; YS00_18; YS00_19; YS00_20; YS00_21; YS00_22; YS00_23; YS00_24; YS00_25; YS00_26; YS00_27; YS00_28; YS00_29; YS00_30; YS00_31; YS00_32; YS00_33; YS00_34; YS00_35; YS00_36; YS00_37; YS00_38; YS00_39;
    Type: Dataset
    Format: application/zip, 17 datasets
    Location Call Number Expected Availability
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  • 7
    Publication Date: 2014-12-23
    Description: EGU2011-4235 The Arctic is undergoing rapid environmental and economic transformations. Recent climate warming, which is simplifying access to oil and gas resources, enabling trans Arctic shipping, and shifting the distribution of harvestable resources, has brought the Arctic Ocean to the top of national and international political agendas. Scientific knowledge of the present status of the Arctic Ocean and the process-based understanding of the mechanics of change are urgently needed to make useful predictions of future conditions throughout the Arctic region. These are required to plan for the consequences of climate change. A step towards improving our capacity to predict future Arctic change was undertaken with the Second International Conference on Arctic Research Planning (ICARP II) meetings in 2005 and 2006, which brought together scientists, policymakers, research managers, Arctic residents, and other stakeholders interested in the future of the Arctic region. The Arctic in Rapid Transition (ART) Initiative developed out of the synthesis of the several resulting ICARP II science plans specific to the marine environment. This process started in October 2008 and has been driven by early career scientists. The ART Initiative is an integrative, international, multi-disciplinary, long-term pan-Arctic network to study changes and feedbacks with respect to physical characteristics and biogeochemical cycles in the Arctic Ocean in a state of rapid transition and its impact on the biological production. The first ART workshop was held in Fairbanks, Alaska, in November 2009 with 58 participants from 9 countries. Workshop discussions and reports were used to develop a science plan that integrates, updates, and develops priorities for Arctic Marine Science over the next decade. The science plan was accepted and approved by the International Arctic Science Committee (IASC) Marine Group, the former Arctic Ocean Science Board. The second ART workshop was held in Winnipeg, Canada, in October 2010 with 20 participants from 7 countries to develop the implementation plan. Our focus within the ART Initiative will be to bridge gaps in knowledge not only across disciplinary boundaries (e.g., biology, geochemistry, geology, meteorology, physical oceanography), but also across geographic (e.g., international boundaries, shelves, margins, and the central Arctic Ocean) and temporal boundaries (e.g., alaeo/geologic records, current process observations, and future modeling studies). This approach of the ART Initiative will provide a means to better understand and predict change, particularly the consequences for biological productivity, and ultimate responses in the Arctic Ocean system. More information about the ART Initiative can be found at http://aosb.arcticportal.org/art.html.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
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  • 8
    facet.materialart.
    Unknown
    Alfred-Wegener-Institut für Polar- und Meeresforschung
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität zu Kiel, GEOMAR Forschungszentrum für Marine Geowissenschaften, Kiel, Kiel, IV, 87 pp . Berichte zur Polar- und Meeresforschung, 455 . DOI hdl:10013/epic.10460.d001.
    Publication Date: 2015-04-07
    Description: The main objective of the study was to investigate seasonal sediment dynarnics on the Laptev Sea shelf. The Laptev Sea comprises one of the largest Siberian shelf areas and is characterized by seasonal ice coverage and thus, by a strong seasonality in sediment input. The pathways and the final fate of the sediments derived from the Siberian hinterland are central questions for understanding the complex land-shelf-ocean interactions and their seasonal variations. In order to characterize seasonal variations in suspended particulate matter (SPM) dynamics on the eastem Laptev Sea shelf, one-year Acoustic Doppler Current Profiler (ADCP) records and complementary optical backscatter profiles from the ice-free period were analyzed. In order to use indirect measuring devices for the quantification of SPM concentration, optical (turbidity meter) and acoustic (ADCP) backscatter sensors were compared to assess their potential for the investigation of SPM dynamics on the Laptev Sea shelf. To estimate SPM concentrations from optical backscatter signals, these were converted using the linear relation between the backscatter signals and SPM concentrations derived from filtered water samples. Applying the theoretical interaction of sound in the water to SPM, the acoustic backscatter signals were transformed adapting a previously established approach. SPM concentrations estimated from the backscattered signals of both sensors showed a close similarity to SPM concentrations obtained from filtered water samples. In general both the ADCPs and the turbidity meters provided good estimations, with ADCPs underestimating and turbidity meters slightly overestimating SPM concentrations. Hence, both sensors can be used for the deterrnination of SPM dynamics On the Laptev Sea shelf with its comparably low SPM concentrations. However, ADCPs are more convenient for investigation of sediment transport dynamics as they provide reasonable SPM concentration and current records for the entire water colurnn simultaneously. Combined turbidity meter, pigment, plankton, and current records were analyzed to describe the con~positiont,r ansport dynamics, and short-term variability of SPM in the nepheloid layers (i.e., layers of increased SPM concentration in the water column) during the ice-free period. The combined measurements indicate that most of the sediment transport takes place in the bottom nepheloid layer On the eastem and the central Laptev Sea shelf. The bottom nepheloid layer comprises riverine material, resuspended bottom material, and decaying organic matter from the upper water column. The SPM concentration within the bottom nepheloid layer decreases from south to north and from east to west, respectively, mainly due to dispersion. On the inner shelf in the vicinity of the Lena Delta the SPM concentration in the surface nepheloid layer is strongly dependent On riverine discharge. On the mid-shelf the formation and dynamics of the surface layer are mainly related to changes in phytoplankton biomass and zooplankton migration. On the eastem Laptev Sea shelf paleo-river valleys act as transport conduits during the ice-free period, where bottom material is resuspended On the mid-shelf during and after storm events and transported onto the inner shelf. On the central Laptev Sea shelf resuspension events seem to be less common and SPM is mainly transported over the continental margin into the deep Arctic Ocean. To investigate seasonal variations in SPM dynamics on the eastem Laptev Sea shelf, one-year records On currents and SPM concentrations were examined. The data indicated that during and shortly after the river-ice breakup (June to early July) sediment transport on the inner shelf is dominated by riverine input and transport onto the mid-shelf within the surface nepheloid layer. When ice-free conditions prevail (mid-July to September), SPM is mainly trapped on the eastern Laptev Sea shelf: SPM discharged by the Lena River is transported within the surface layer onto the mid-shelf, where it sinks through the water column into the bottom nepheloid layer. In the bottom layer it is transported back onto the inner shelf with additional bottom material, which was resuspended during and after storm events. On the inner shelf the material is partly conveyed back into the surface layer by turbid mixing and carried out onto the shelf again. During freeze-up (October) SPM in the surface layer on the inner shelf is rather incorporated into newly formed ice and partly transported with the ice over the continental margin into the deep Arctic Ocean. Beneath the ice Cover (November to JuneIJuly) on the inner shelf SPM slowly sinks and sediment transport is of minor importance. However, beneath the polynya bottom material is still resuspended after storrn events and transported onto the inner shelf where it temporarily settles. The data suggest a quasi-estuarine sediment circulation and a sediment export dominated by ice export rather than bottom transport on the eastem Laptev Sea shelf. Since for the first time currents and SPM concentrations were recorded simultaneously for a one-year period, the unique dataset gave new insights into sediment dynamics on the Laptev Sea shelf and its complex land-shelf-ocean interactions. The data provided the basis for a conceptual model of sediment transport on the Laptev Sea shelf, which emphasizes the significance of sea ice export for the sediment budget of the Laptev Sea shelf and as a sediment source for the deep Arctic Ocean. The conceptual model can presumably be extended to other Siberian shelf seas.
    Type: Thesis , NonPeerReviewed
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