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  • 1
    Online Resource
    Online Resource
    Neodymium isotopes and rare earth element distribution in the Barents Sea, Arctic Ocean (2015)
    Saint Petersburg
    Details Availability
    Keywords: Hochschulschrift
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (60 Blatt = 2,3 MB) , Illustrationen
    URL: https://oceanrep.geomar.de/31964/
    Language: English
    Note: Zusammenfassung in englischer und russischer Sprache
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    Link to Library Catalog
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  • 2
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    Arctic – Atlantic Exchange of the Dissolved Micronutrients Iron, Manganese, Cobalt, Nickel, Copper and Zinc With a Focus on Fram Strait (2022)
    Details
    Publication Date: 2022-10-04
    Description: The Arctic Ocean is considered a source of micronutrients to the Nordic Seas and the North Atlantic Ocean through the gateway of Fram Strait (FS). However, there is a paucity of trace element data from across the Arctic Ocean gateways, and so it remains unclear how Arctic and North Atlantic exchange shapes micronutrient availability in the two ocean basins. In 2015 and 2016, GEOTRACES cruises sampled the Barents Sea Opening (GN04, 2015) and FS (GN05, 2016) for dissolved iron (dFe), manganese (dMn), cobalt (dCo), nickel (dNi), copper (dCu) and zinc (dZn). Together with the most recent synopsis of Arctic‐Atlantic volume fluxes, the observed trace element distributions suggest that FS is the most important gateway for Arctic‐Atlantic dissolved micronutrient exchange as a consequence of Intermediate and Deep Water transport. Combining fluxes from FS and the Barents Sea Opening with estimates for Davis Strait (GN02, 2015) suggests an annual net southward flux of 2.7 ± 2.4 Gg·a−1 dFe, 0.3 ± 0.3 Gg·a−1 dCo, 15.0 ± 12.5 Gg·a−1 dNi and 14.2 ± 6.9 Gg·a−1 dCu from the Arctic toward the North Atlantic Ocean. Arctic‐Atlantic exchange of dMn and dZn were more balanced, with a net southbound flux of 2.8 ± 4.7 Gg·a−1 dMn and a net northbound flux of 3.0 ± 7.3 Gg·a−1 dZn. Our results suggest that ongoing changes to shelf inputs and sea ice dynamics in the Arctic, especially in Siberian shelf regions, affect micronutrient availability in FS and the high latitude North Atlantic Ocean.
    Description: Plain Language Summary: Recent studies have proposed that the Arctic Ocean is a source of micronutrients such as dissolved iron (dFe), manganese (dMn), cobalt (dCo), nickel (dNi), copper (dCu) and zinc (dZn) to the North Atlantic Ocean. However, data at the Arctic Ocean gateways including Fram Strait and the Barents Sea Opening have been missing to date and so the extent of Arctic micronutrient transport toward the Atlantic Ocean remains unquantified. Here, we show that Fram Strait is the most important gateway for Arctic‐Atlantic micronutrient exchange which is a result of deep water transport at depths 〉500 m. Combined with a flux estimate for Davis Strait, this study suggests that the Arctic Ocean is a net source of dFe, dNi and dCu, and possibly also dCo, toward the North Atlantic Ocean. Arctic‐Atlantic dMn and dZn exchange seems more balanced. Properties in the East Greenland Current showed substantial similarities to observations in the upstream Central Arctic Ocean, indicating that Fram Strait may export micronutrients from Siberian riverine discharge and shelf sediments 〉3,000 km away. Increasing Arctic river discharge, permafrost thaw and coastal erosion, all consequences of ongoing climate change, may therefore alter future Arctic Ocean micronutrient transport to the North Atlantic Ocean.
    Description: Key Points: Fram Strait is the major gateway for Arctic‐Atlantic exchange of the dissolved micronutrients Fe, Mn, Co, Ni, Cu and Zn. The Arctic is a net source of dissolved Fe, Co, Ni and Cu to the Nordic Seas and toward the North Atlantic; Mn and Zn exchange are balanced. Waters of the Central Arctic Ocean, including the Transpolar Drift, are the main drivers of gross Arctic micronutrient export.
    Description: German Research Foundation
    Description: Netherlands Organization for Scientific Research
    Description: https://doi.pangaea.de/10.1594/PANGAEA.859558
    Description: https://doi.pangaea.de/10.1594/PANGAEA.871030
    Description: https://doi.pangaea.de/10.1594/PANGAEA.868396
    Description: https://doi.pangaea.de/10.1594/PANGAEA.905347
    Description: https://dataportal.nioz.nl/doi/10.25850/nioz/7b.b.jc
    Description: https://doi.pangaea.de/10.1594/PANGAEA.933431
    Description: https://www.bco-dmo.org/dataset/718440
    Description: https://doi.org/10.1594/PANGAEA.936029
    Description: https://doi.org/10.1594/PANGAEA.936027
    Description: https://doi.pangaea.de/10.1594/PANGAEA.927429
    Keywords: ddc:551.9
    Language: English
    Type: doc-type:article
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    CITATION GEO-LEO
  • 3
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    Dissolved neodymium (Nd) isotope compositions and rare earth element (REE) concentrations along with stable oxygen isotope compositions measured on water bottle samples collected during PU2014 to the Barents Sea in 2014 (2018)
    PANGAEA
    In:  Supplement to: Laukert, Georgi; Makhotin, Mikhail; Petrova, Mariia V; Frank, Martin; Hathorne, Ed C; Bauch, Dorothea; Böning, Philipp; Kassens, Heidemarie (2019): Water mass transformation in the Barents Sea inferred from radiogenic neodymium isotopes, rare earth elements and stable oxygen isotopes. Chemical Geology, 511, 416-430, https://doi.org/10.1016/j.chemgeo.2018.10.002
    Details
    Publication Date: 2024-03-05
    Description: Nearly half the inflow of warm and saline Atlantic Water (AW) to the Arctic Ocean is substantially cooled and freshened in the Barents Sea, which is therefore considered a key region for water mass transformation in the Arctic Mediterranean. Numerous studies have focused on this transformation and the increasing influence of AW on Arctic climate and biodiversity, yet geochemical investigations of these processes have been scarce. Using the first comprehensive data set of the distributions of dissolved radiogenic neodymium (Nd) isotopes (expressed as ɛNd), rare earth elements (REE) and stable oxygen isotope (δ18O) compositions from this region we are able to constrain the transport and transformation of AW in the Barents Sea and to investigate which processes change the chemical composition of the water masses beyond what is expected from circulation and mixing. Inflowing AW and Norwegian Coastal Water (NCW) both exhibit distinctly unradiogenic ɛNd signatures of -12.4 and -14.5, respectively, whereas cold and dense Polar Water (PW) has considerably more radiogenic ɛNd signatures reaching up to -8.1. Locally formed Barents Sea Atlantic Water (BSAW) and Barents Sea Arctic Atlantic Water (BSAAW) are encountered in the northeastern Barents Sea and have intermediate ɛNd values resulting from admixture of PW containing small amounts of riverine freshwater from the Ob (〈 ~1.1 %) to AW and NCW. Similar to the Laptev Sea, the dissolved Nd isotope composition in the Barents Sea seems to be mainly controlled by water mass advection and mixing despite its shallow water depth. Strikingly, the BSAW and BSAAW are marked by the lowest REE concentrations reaching 11 pmol/kg for Nd ([Nd]), which in contrast to the Nd isotopes, cannot be attributed to the admixture of REE-rich Ob freshwater to AW or NCW ([Nd] = 16.7, and 22 pmol/kg, respectively) and instead reflects REE removal from the dissolved phase with preferential removal of the light over the heavy REEs. The REE removal is, however, not explainable by estuarine REE behavior alone, suggesting that scavenging by (re)suspended (biogenic) particles occurs locally in the Barents Sea. Regardless of the exact cause of REE depletion, we show that AW transformation is accompanied by geochemical changes independent of water mass mixing.
    Keywords: Calculated; Cerium, dissolved; Classification; CTD; CTD/Rosette; CTD-RO; Date/Time of event; Density, sigma500; Density, sigma-theta (0); DEPTH, water; Dysprosium, dissolved; Elevation of event; Erbium, dissolved; Europium, dissolved; Event label; Gadolinium, dissolved; GEOTRACES; Global marine biogeochemical cycles of trace elements and their isotopes; Holmium, dissolved; Isotope dilution; Lanthanum, dissolved; Laptev Sea System; Latitude of event; Longitude of event; LSS; Lutetium, dissolved; Neodymium, dissolved; Neodymium-143/Neodymium-144 ratio; Neodymium-143/Neodymium-144 ratio, standard deviation; Oxygen; Oxygen saturation; pH; Phosphate; Praseodymium, dissolved; Pressure, water; Professor Molchanov; PU2014; PU2014/042; PU2014/049; PU2014/054; PU2014/099; PU2014/115; PU2014/119; PU2014/126; PU2014/129; Recalculated from ml/l by using (ml/l)*44.66; Salinity; Samarium, dissolved; Silicate; Temperature, water; Temperature, water, potential; Terbium, dissolved; Thulium, dissolved; Ytterbium, dissolved; Yttrium, dissolved; δ18O, water; ε-Neodymium; ε-Neodymium, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 1023 data points
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    DATA PANGAEA
  • 4
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    Neodymium isotopes and rare earth element distribution in the Barents Sea, Arctic Ocean (2015)
    In:  (Master thesis), Saint Petersburg State University / University of Hamburg, Saint Petersburg / Hamburg, 60 pp
    Details
    Publication Date: 2016-04-05
    Description: The Barents Sea is a key region for water mass modification in the Arctic. Interaction with atmosphere and ice, and mixing in the Barents Sea, significantly modify the water masses before they enter the Arctic Basin. In the eastern Barents Sea mixing of water masses generates dense Barents Sea Water (BSW) which inflows the Arctic Ocean to form the Arctic Intermediate Waters. BSW plays an important role in the maintenance of the Arctic halocline. To study the interannual variability and evolution of water masses passing through the Barents Sea could be useful for better understanding of the climate change in the Northern Hemisphere. Neodymium is one of number tracers which have been used to trace the distribution and circulation of water masses within the Barents Sea. Neodymium isotopic composition (expressed as ɛNd) has been successfully applied for water mass tracing due to the residence time of Nd in the oceans being shorter than the ocean overturning time and due to independence of Nd from biological fractionation and physical processes. This work examines the major water masses within the Barents Sea, using temperature, salinity, REE concentrations and ɛNd isotopic composition data of seawater. Water within the Barents Sea are a mixture of the saline, warm and unradiogenic Atlantic water; fresh, warm, unradiogenic, and REE-enriched Coastal water from the Kola Peninsula; fresh, cold, and relatively radiogenic Arctic surface water; and fresh, most radiogenic in this area and depleted in LREE Ob/Yenisei River Current water in different proportion. Particle scavenging is very important processes for modification of chemical content of water masses. As a result of water mass transformation, waters in southwestern part of the sea have ɛNd=-12.9±0.2 with relatively low HREE/LREE ratio=3.20±0.30. In the central part of the sea, where the Arctic waters have a stronger influence, ɛNd is -10.6±0.2 in the surface layer, but near the bottom the Nd isotopic signature indicates presence of Atlantic water (ɛNd=-12.0±0.2). The Nd isotopic composition in the northern parts of Barents Sea is more radiogenic (ɛNd=-9.1±0.3) and a maximum of the HREE/LREE ratio is reached due to particle scavenging. In the northeastern part of the study area the most radiogenic signature (ɛNd=-8.5±0.3) was determined reflecting admixture of radiogenic Ob/Yenisei River water.
    Type: Thesis , NonPeerReviewed
    Format: text
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    OceanRep: Thesis - not published by a publisher
  • 5
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    The Transpolar Drift as a Source of Riverine and Shelf-Derived Trace Elements to the Central Arctic Ocean (2020)
    AGU (American Geophysical Union) | Wiley
    Details
    Publication Date: 2023-02-08
    Description: A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river‐influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high‐resolution pan‐Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25‐50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle‐reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the open ocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 ± 0.4 Sv (106 m3 s‐1). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologic cycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean.
    Type: Article , PeerReviewed
    Format: text
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
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    Mercury species export from the Arctic to the Atlantic Ocean (2020)
    Elsevier
    Details
    Publication Date: 2023-02-08
    Description: Highlights • First full water column measurements of tHg, pHg, MMHg, MeHg, and DGM at the Fram Strait. • The Arctic Ocean exports tHg- and MeHg-enriched waters to the North Atlantic Ocean. • The Arctic Ocean exports about 18 Mg y−1 of tHg to the Nordic Seas and North Atlantic. • About 40% of exported tHg is in the form of MeHg. The Fram Strait is the only deep connection between the Arctic and Atlantic Oceans. The main water and mercury (Hg) fluxes between these oceans occur via the Fram Strait and Barents Sea Opening. Several Hg mass balance studies indicated a net Hg export from the Arctic to the Atlantic Ocean. However, in the absence of Hg measurements in the Fram Strait and Barents Sea Opening, these estimates were based on North Atlantic and central Arctic Ocean data alone. Here, we refine the Arctic total Hg (tHg) and methylated Hg (MeHg) mass budgets using new data acquired during the 2015 GEOTRACES (section GN04) TransArcII cruise in the Barents Sea Opening and the 2016 GEOTRACES (section GN05) GRIFF cruise, which covered the Fram Strait and Northeast Greenland Shelf. Total Hg increased westward along the Fram Strait transect, reaching the highest concentrations on the Northeast Greenland Shelf. Concentrations of tHg averaged 1.29 ± 0.43 pM in the East Greenland Current, while core waters of the West Spitsbergen Current had average values of 0.80 ± 0.26 pM. Using our new data, we estimate that 43 ± 9 Mg y−1 of tHg is transported to the Arctic Ocean in the core of the West Spitsbergen Current, while 54 ± 13 Mg y−1 of tHg is exported from the Arctic Ocean in the East Greenland Current and Recirculated Atlantic Water. This results in a net tHg export of 11 ± 8 Mg y−1via the Fram Strait. We find a shallow MeHg maximum (at 150 m depth) in the East Greenland Current, in agreement to what was reported for the central Arctic Ocean and Canadian Arctic Archipelago. The West Spitsbergen Current is characterized by lower MeHg concentrations and a deeper MeHg maximum, that is located at approximately 1000 m depth. We estimate a net MeHg export of 6 ± 2 Mg y−1 from the Arctic Ocean via the Fram Strait, which is nearly half of the exported tHg. Most of the exported MeHg is in the form of DMHg (2:1 ratio of dimethylmercury to monomethylmercury). Previous studies reported lower MeHg proportions. Our observations show that the Arctic Ocean is producing and exporting MeHg to the Atlantic Ocean. In total, the Arctic Ocean exports about 18 Mg y−1 of tHg to the Nordic Seas and North Atlantic via the Fram Strait and Davis Strait, of which 7.5 Mg y−1 is in the MeHg form.
    Type: Article , PeerReviewed
    Format: text
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 7
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    Water mass transformation in the Barents Sea inferred from radiogenic neodymium isotopes, rare earth elements and stable oxygen isotopes (2019)
    Elsevier
    In:  Chemical Geology, 511 . pp. 416-430.
    Details
    Publication Date: 2022-01-31
    Description: Highlights • First comprehensive seawater Nd isotope and REE data set for the Barents Sea • Water masses traced with Nd isotopes, salinity and stable oxygen isotopes • No release of particulate REEs to the dissolved load except for cerium • Transformation of Atlantic Water accompanied by pronounced REE removal from the dissolved phase Abstract Nearly half the inflow of warm and saline Atlantic Water (AW) to the Arctic Ocean is substantially cooled and freshened in the Barents Sea, which is therefore considered a key region for water mass transformation in the Arctic Mediterranean. Numerous studies have focused on this transformation and the increasing influence of AW on Arctic climate and biodiversity, yet geochemical investigations of these processes have been scarce. Using the first comprehensive data set of the distributions of dissolved radiogenic neodymium (Nd) isotopes (expressed as ɛNd), rare earth elements (REE) and stable oxygen isotope (δ18O) compositions from this region we are able to constrain the transport and transformation of AW in the Barents Sea and to investigate which processes change the chemical composition of the water masses beyond what is expected from circulation and mixing. Inflowing AW and Norwegian Coastal Water (NCW) both exhibit distinctly unradiogenic ɛNd signatures of −12.4 and −14.5, respectively, whereas cold and dense Polar Water (PW) has considerably more radiogenic ɛNd signatures reaching up to −8.1. Locally formed Barents Sea Atlantic Water (BSAW) and Barents Sea Arctic Atlantic Water (BSAAW) are encountered in the northeastern Barents Sea and have intermediate ɛNd values resulting from admixture of PW containing small amounts of riverine freshwater from the Ob (〈~1.1%) to AW and NCW. Similar to the Laptev Sea, the dissolved Nd isotope composition in the Barents Sea seems to be mainly controlled by water mass advection and mixing despite its shallow water depth. Strikingly, the BSAW and BSAAW are marked by the lowest REE concentrations reaching 11 pmol/kg for Nd ([Nd]), which in contrast to the Nd isotopes, cannot be attributed to the admixture of REE-rich Ob freshwater to AW or NCW ([Nd] = 16.7, and 22 pmol/kg, respectively) and instead reflects REE removal from the dissolved phase with preferential removal of the light over the heavy REEs. The REE removal is, however, not explainable by estuarine REE behavior alone, suggesting that scavenging by (re)suspended (biogenic) particles occurs locally in the Barents Sea. Regardless of the exact cause of REE depletion, we show that AW transformation is accompanied by geochemical changes independent of water mass mixing. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    DOI: 10.1016/j.chemgeo.2018.10.002
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
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    Arctic – Atlantic exchange of the dissolved micronutrients Iron, Manganese, Cobalt, Nickel, Copper and Zinc with a focus on Fram Strait (2022)
    AGU (American Geophysical Union) | Wiley
    Details
    Publication Date: 2024-02-07
    Description: The Arctic Ocean is considered a source of micronutrients to the Nordic Seas and the North Atlantic Ocean through the gateway of Fram Strait. However, there is a paucity of trace element data from across the Arctic Ocean gateways, and so it remains unclear how Arctic and North Atlantic exchange shapes micronutrient availability in the two ocean basins. In 2015 and 2016, GEOTRACES cruises sampled the Barents Sea Opening (GN04, 2015) and Fram Strait (GN05, 2016) for dissolved iron (dFe), manganese (dMn), cobalt (dCo), nickel (dNi), copper (dCu) and zinc (dZn). Together with the most recent synopsis of Arctic-Atlantic volume fluxes, the observed trace element distributions suggest that Fram Strait is the most important gateway for Arctic-Atlantic dissolved micronutrient exchange as a consequence of Intermediate and Deep Water transport. Combining fluxes from Fram Strait and the Barents Sea Opening with estimates for Davis Strait (GN02, 2015) suggests an annual net southward flux of 2.7 ± 2.4 Gg·a-1 dFe, 0.3 ± 0.3 Gg·a-1 dCo, 15.0 ± 12.5 Gg·a-1 dNi and 14.2 ± 6.9 Gg·a-1 dCu from the Arctic towards the North Atlantic Ocean. Arctic-Atlantic exchange of dMn and dZn were more balanced, with a net southbound flux of 2.8 ± 4.7 Gg·a-1 dMn and a net northbound flux of 3.0 ± 7.3 Gg·a-1 dZn. Our results suggest that ongoing changes to shelf inputs and sea ice dynamics in the Arctic, especially in Siberian shelf regions, affect micronutrient availability in Fram Strait and the high latitude North Atlantic Ocean.
    Type: Article , PeerReviewed
    Format: text
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 9
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    The Transpolar Drift as a Source of Riverine and Shelf-Derived Trace Elements to the Central Arctic Ocean (2020)
    In:  EPIC3Journal of Geophysical Research: Oceans, 125(5), pp. e2019JC015920
    Details
    Publication Date: 2020-07-09
    Description: Abstract A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river-influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high-resolution pan-Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25�50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle-reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the open ocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 ± 0.4 Sv (106 m3 s�1). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologic cycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 10
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    Mercury Export Flux in the Arctic Ocean Estimated from 234Th/238U Disequilibria (2020)
    In:  EPIC3ACS Earth and Space Chemistry, 4(5), pp. 795-801
    Details
    Publication Date: 2021-03-16
    Description: High mercury (Hg) levels have been observed for arctic biota, despite limited local sources of anthropogenic Hg in the Arctic. Scavenging of Hg exerts an important control on the residence time of Hg in surface waters. The downward Hg export flux and Hg burial rates in bottom sediments are not well-constrained as a result of the lack of particulate Hg (Hgp) observations in the Arctic Ocean. Here, we estimated downward Hg export flux based on Hg concentrations in suspended particulate matter (SPM) and using the radionuclide pair 234Th/238U, coupled to Hgp/234Th ratios in particles. Using new observations made during the German GEOTRACES TransArcII (GN04) and the U.S. Arctic GEOTRACES (GN01) cruises in August–October 2015, we estimated the Hgp export flux in the central Arctic Ocean and the outer shelf. We find that 81 ± 58 Mg year–1 Hgp is exported from the upper 100 m, of which 16 ± 10 Mg year–1 is ultimately buried in marine sediments. An extrapolation to the entire Arctic Ocean, including the inner shelf, results in 156 Mg year–1Hgp export from the surface ocean and 28 Mg year–1 Hg burial rate. Our study shows that the Hgp export flux could be higher than previously thought, and this should be taken into consideration for future arctic Hg budget estimations.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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