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  1. AU="Rutgers van der Loeff, Michiel M"
  2. AU="Penak, Bianca"
  3. AU="Shao, Shiliang"
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  5. AU="Jian Zeng"
  6. AU="Toyoda, Masanori"
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  10. AU="Elwany Elsnosy"
  11. AU="Bertilacchi, Maria Sofia"
  12. AU="I.C.F.Wong, "
  13. AU="Pootrakul, Llana"
  14. AU="Heydari Beni, Nargess"
  15. AU="Pinter, Emily N"
  16. AU="Hogan, William J"
  17. AU="Tikute, Sanjaykumar"
  18. AU="Lu Shi"
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  1. Artikel ; Online: The 79°N Glacier cavity modulates subglacial iron export to the NE Greenland Shelf.

    Krisch, Stephan / Hopwood, Mark James / Schaffer, Janin / Al-Hashem, Ali / Höfer, Juan / Rutgers van der Loeff, Michiel M / Conway, Tim M / Summers, Brent A / Lodeiro, Pablo / Ardiningsih, Indah / Steffens, Tim / Achterberg, Eric Pieter

    Nature communications

    2021  Band 12, Heft 1, Seite(n) 3030

    Abstract: Approximately half of the freshwater discharged from the Greenland and Antarctic Ice Sheets enters the ocean subsurface as a result of basal ice melt, or runoff draining via the grounding line of a deep ice shelf or marine-terminating glacier. Around ... ...

    Abstract Approximately half of the freshwater discharged from the Greenland and Antarctic Ice Sheets enters the ocean subsurface as a result of basal ice melt, or runoff draining via the grounding line of a deep ice shelf or marine-terminating glacier. Around Antarctica and parts of northern Greenland, this freshwater then experiences prolonged residence times in large cavities beneath floating ice tongues. Due to the inaccessibility of these cavities, it is unclear how they moderate the freshwater associated supply of nutrients such as iron (Fe) to the ocean. Here, we show that subglacial dissolved Fe export from Nioghalvfjerdsbrae (the '79°N Glacier') is decoupled from particulate inputs including freshwater Fe supply, likely due to the prolonged ~162-day residence time of Atlantic water beneath Greenland's largest floating ice-tongue. Our findings indicate that the overturning rate and particle-dissolved phase exchanges in ice cavities exert a dominant control on subglacial nutrient supply to shelf regions.
    Sprache Englisch
    Erscheinungsdatum 2021-05-24
    Erscheinungsland England
    Dokumenttyp Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-021-23093-0
    Datenquelle MEDical Literature Analysis and Retrieval System OnLINE

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  2. Artikel ; Online: Dissolved, labile and total particulate trace metal dynamics on the northeast Greenland Shelf

    Chen, Xue-Gang / Krisch, Stephan / Al-Hashem, Ali / Hopwood, Mark J. / Rutgers van der Loeff, Michiel M. / Huhn, Oliver / Lodeiro, Pablo / Steffens, Tim / Achterberg, Eric P.

    2022  

    Abstract: We present high-resolution profiles of dissolved, labile and total particulate trace metals (TMs) on the Northeast Greenland shelf from GEOTRACES cruise GN05 in August 2016. Combined with radium isotopes, stable oxygen isotopes, and noble gas ... ...

    Abstract We present high-resolution profiles of dissolved, labile and total particulate trace metals (TMs) on the Northeast Greenland shelf from GEOTRACES cruise GN05 in August 2016. Combined with radium isotopes, stable oxygen isotopes, and noble gas measurements, elemental distributions suggest that TM dynamics were mainly regulated by the mixing between North Atlantic-derived Intermediate Water, enriched in labile particulate TMs (LpTMs), and Arctic surface waters, enriched in Siberian shelf-derived dissolved TMs (dTMs; Co, Cu, Fe, Mn, and Ni) carried by the Transpolar Drift. These two distinct sources were delineated by salinity-dependent variations of dTM and LpTM concentrations and the proportion of dTMs relative to the total dissolved and labile particulate ratios. Locally produced meltwater from the Nioghalvfjerdsbræ (79NG) glacier cavity, distinguished from other freshwater sources using helium excess, contributed a large pool of dTMs to the shelf inventory. Localized peaks in labile and total particulate Cd, Co, Fe, Mn, Ni, Cu, Al, V, and Ti in the cavity outflow, however, were not directly contributed by submarine melting. Instead, these particulate TMs were mainly supplied by the re-suspension of cavity sediment particles. Currently, Arctic Ocean outflows are the most important source of dFe, dCu and dNi on the shelf, while LpTMs and up to 60% of dMn and dCo are mainly supplied by subglacial discharge from the 79NG cavity. Therefore, changes in the cavity-overturning dynamics of 79NG induced by glacial retreat, and alterations in the transport of Siberian shelf-derived materials with the Transport Drift may shift the shelf dTM-LpTM stoichiometry in the future. Key Points The overall dissolved and particulate trace metal dynamics were mainly regulated by the mixing with Arctic surface waters Resuspension of cavity sediments is a major localized source of labile and total particulate Cd, Co, Fe, Mn, Ni, Cu, Al, V, and Ti Whilst dissolved and particulate trace metals are mostly coupled on the Greenland shelf, ...
    Thema/Rubrik (Code) 551
    Sprache Englisch
    Verlag AGU (American Geophysical Union)
    Erscheinungsland de
    Dokumenttyp Artikel ; Online
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  3. Artikel ; Online: The 79°N Glacier cavity modulates subglacial iron export to the NE Greenland Shelf

    Krisch, Stephan / Hopwood, Mark J. / Schaffer, Janin / Al-Hashem, Ali / Höfer, Juan / Rutgers van der Loeff, Michiel M. / Conway, Tim M. / Summers, Brent A. / Lodeiro, Pablo / Ardiningsih, Indah / Steffens, Tim / Achterberg, Eric P.

    2021  

    Abstract: Approximately half of the freshwater discharged from the Greenland and Antarctic Ice Sheets enters the ocean subsurface as a result of basal ice melt, or runoff draining via the grounding line of a deep ice shelf or marine-terminating glacier. Around ... ...

    Abstract Approximately half of the freshwater discharged from the Greenland and Antarctic Ice Sheets enters the ocean subsurface as a result of basal ice melt, or runoff draining via the grounding line of a deep ice shelf or marine-terminating glacier. Around Antarctica and parts of northern Greenland, this freshwater then experiences prolonged residence times in large cavities beneath floating ice tongues. Due to the inaccessibility of these cavities, it is unclear how they moderate the freshwater associated supply of nutrients such as iron (Fe) to the ocean. Here, we show that subglacial dissolved Fe export from Nioghalvfjerdsbrae (the ‘79°N Glacier’) is decoupled from particulate inputs including freshwater Fe supply, likely due to the prolonged ~162-day residence time of Atlantic water beneath Greenland’s largest floating ice-tongue. Our findings indicate that the overturning rate and particle-dissolved phase exchanges in ice cavities exert a dominant control on subglacial nutrient supply to shelf regions.
    Thema/Rubrik (Code) 551
    Sprache Englisch
    Erscheinungsdatum 2021-05-24
    Verlag Nature Research
    Erscheinungsland de
    Dokumenttyp Artikel ; Online
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  4. Artikel ; Online: Arctic – Atlantic exchange of the dissolved micronutrients Iron, Manganese, Cobalt, Nickel, Copper and Zinc with a focus on Fram Strait

    Krisch, Stephan / Hopwood, Mark J. / Roig, Stephane / Gerringa, Loes J.A. / Middag, Rob / Rutgers van der Loeff, Michiel M. / Petrova, Mariia V. / Lodeiro, Pablo / Colombo, Manuel / Cullen, Jay T. / Jackson, Sarah L. / Heimbürger‐Boavida, Lars‐Eric / Achterberg, Eric P.

    2022  

    Abstract: 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 ... ...

    Abstract 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.
    Thema/Rubrik (Code) 551
    Sprache Englisch
    Verlag AGU (American Geophysical Union)
    Erscheinungsland de
    Dokumenttyp Artikel ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  5. Buch ; Online: Decrease in 230Th in the Amundsen Basin since 2007

    Valk, Ole / Rutgers van der Loeff, Michiel M. / Geibert, Walter / Gdaniec, Sandra / Moran, S. Bradley / Lepore, Kate / Edwards, Robert Lawrence / Lu, Yanbin / Puigcorbé, Viena / Casacuberta, Nuria / Paffrath, Ronja / Smethie, William / Roy-Barman, Matthieu

    eISSN: 1812-0792

    far-field effect of increased scavenging on the shelf?

    2020  

    Abstract: This study provides dissolved and particulate 230 Th and 232 Th results as well as particulate 234 Th data collected during expeditions to the central Arctic Ocean (GEOTRACES, an international project to identify processes and quantify fluxes that ... ...

    Abstract This study provides dissolved and particulate 230 Th and 232 Th results as well as particulate 234 Th data collected during expeditions to the central Arctic Ocean (GEOTRACES, an international project to identify processes and quantify fluxes that control the distributions of trace elements; sections GN04 and GIPY11). Constructing a time series of dissolved 230 Th from 1991 to 2015 enables the identification of processes that control the temporal development of 230 Th distributions in the Amundsen Basin. After 2007, 230 Th concentrations decreased significantly over the entire water column, particularly between 300 and 1500 m. This decrease is accompanied by a circulation change, evidenced by a concomitant increase in salinity. A potentially increased inflow of water of Atlantic origin with low dissolved 230 Th concentrations leads to the observed depletion in dissolved 230 Th in the central Arctic. Because atmospherically derived tracers (chlorofluorocarbon (CFC), sulfur hexafluoride (SF 6 )) do not reveal an increase in ventilation rate, it is suggested that these interior waters have undergone enhanced scavenging of Th during transit from Fram Strait and the Barents Sea to the central Amundsen Basin. The 230 Th depletion propagates downward in the water column by settling particles and reversible scavenging.
    Thema/Rubrik (Code) 333 ; 511
    Sprache Englisch
    Erscheinungsdatum 2020-02-14
    Erscheinungsland de
    Dokumenttyp Buch ; Online
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  6. Buch ; Online: Grain size effects on excess Thorium-230 of sediment cores from the Southern Ocean and the South East Atlantic, supplementary data to: Kretschmer, Sven; Geibert, Walter; Rutgers van der Loeff, Michiel M; Mollenhauer, Gesine (2010): Grain size effects on Th-230 (xs) inventories in opal-rich and carbonate-rich marine sediments. Earth and Planetary Science Letters, 294(1-2), 131-142

    Kretschmer, Sven / Geibert, Walter / Mollenhauer, Gesine / Rutgers van der Loeff, Michiel M

    2010  

    Abstract: Excess Thorium-230 (230Thxs) as a constant flux tracer is an essential tool for paleoceanographic studies, but its limitations for flux normalization are still a matter of debate. In regions of rapid sediment accumulation, it has been an open question if ...

    Abstract Excess Thorium-230 (230Thxs) as a constant flux tracer is an essential tool for paleoceanographic studies, but its limitations for flux normalization are still a matter of debate. In regions of rapid sediment accumulation, it has been an open question if 230Thxs-normalized fluxes are biased by particle sorting effects during sediment redistribution. In order to study the sorting effect of sediment transport on 230Thxs, we analyzed the specific activity of 230Thxs in different particle size classes of carbonate-rich sediments from the South East Atlantic, and of opal-rich sediments from the Atlantic sector of the Southern Ocean. At both sites, we compare the 230Thxs distribution in neighboring high vs. low accumulation settings. Two grain-size fractionation methods are explored.

    We find that the 230Thxs distribution is strongly grain size dependent, and 50-90% of the total 230Thxs inventory is concentrated in fine material smaller than 10 ?m, which is preferentially deposited at the high accumulation sites. This leads to an overestimation of the focusing factor Psi, and consequently to an underestimation of the vertical flux rate at such sites. The distribution of authigenic uranium indicates that fine organic-rich material has also been re-deposited from lateral sources. If the particle sorting effect is considered in the flux calculations, it reduces the estimated extent of sediment focusing. In order to assess the maximum effect of particle sorting on Psi, we present an extreme scenario, in which we assume a lateral sediment supply of only fine material (< 10 ?m). In this case, the focusing factor of the opal-rich core would be reduced from Psi = 5.9 to Psi = 3.2. In a more likely scenario, allowing silt-sized material to be transported, Psi is reduced from 5.9 to 5.0 if particle sorting is taken into consideration. The bias introduced by particle sorting is most important for strongly focused sediments.

    Comparing 230Thxs-normalized mass fluxes biased by sorting effects with uncorrected mass fluxes, we suggest that 230Thxs-normalization is still a valid tool to correct for lateral sediment redistribution. However, differences in focusing factors between core locations have to be evaluated carefully, taking the grain size distributions into consideration.

    REFERENCE:
    Kretschmer, Sven (2010): The Influence of particle size, composition, and transport on the distribution of 230Thxs, 231Paxs, and 10Be in marine sediment. PhD Thesis, Elektronische Dissertationen an der Staats- und Universit?tsbibliothek Bremen, Germany, 134 pp
    Sprache Englisch
    Erscheinungsverlauf 2010-9999
    Umfang Online-Ressource
    Verlag PANGAEA - Data Publisher for Earth & Environmental Science
    Erscheinungsort Bremen/Bremerhaven
    Dokumenttyp Buch ; Online
    Anmerkung This dataset is cited by urn:urn:nbn:de:gbv:46-00101745-16 ; This dataset is supplement to doi:10.1016/j.epsl.2010.03.021
    DOI 10.1594/PANGAEA.753876
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  7. Buch ; Online: Radionuclides measured on 21 water bottle profiles during POLARSTERN cruise ANT-XXIV/3, supplementary data to: Venchiarutti, C?lia; Rutgers van der Loeff, Michiel M; Stimac, Ingrid (2011): Scavenging of 231Pa and thorium isotopes based on dissolved and size-fractionated particulate distributions at Drake Passage (ANTXXIV-3). Deep Sea Research Part II: Topical Studies in Oceanography, 58(25-26), 2767-2784

    Venchiarutti, C?lia / Rutgers van der Loeff, Michiel M / Stimac, Ingrid

    2010  

    Abstract: Drake Passage is a major route for many water masses from the strong Antarctic Circumpolar Current. During the ANTXXIV-3 expedition (in 2008) the vertical distributions of dissolved and size-fractionated particulate 231Pa and thorium isotopes (230Th, ... ...

    Abstract Drake Passage is a major route for many water masses from the strong Antarctic Circumpolar Current. During the ANTXXIV-3 expedition (in 2008) the vertical distributions of dissolved and size-fractionated particulate 231Pa and thorium isotopes (230Th, 232Th and 234Th) were investigated in order to better define the scavenging regimes and the effects of the oceanic circulation on the fate of particulate material and on the Pa-Th distributions in the water column.
    The reversible scavenging-model applied to both 230Th and 234Th, in the upper 1500 m depth, gives estimates of the particle dynamics (settling velocities S~ 500-1300 m/y, adsorption and desorption rate constants of 0.1-0.4 1/y and 1-6 1/y respectively). Particulate 234Th/230Th activity ratio shows a depth dependence, with decreasing ratio with increasing depth in agreement with previous studies, but no relationship with particle size was found.
    231Pa and thorium isotope fractionation and partition coefficients were investigated with particle size vs depth and latitude and appear to vary horizontally following a North-South gradient. This suggests that both radionuclides are mostly bound to the fine suspended particles.
    At Drake Passage, the 230Thxs distribution is controlled by a southward upwelling of deep water (clearly visible on the vertical section of total 230Thxs, defined as dissolved + particulate concentrations) and reversible-scavenging processes (linear increase of 230Thxs with increasing depth) with North of the Southern ACC Front, higher settling velocities and less adsorption/desorption cycles, than South of it.
    Distributions of dissolved and total 231Paxs also reflect the influence of the North-South upwelling but somehow this effect appears to be limited to the upper 1500 m depth of the water column. Below this depth, 231Paxs vertical profiles exhibit contrasted concentrations, with some high dissolved activities in the deep water of the stations in the northern part of the ACC and not South of the ACC. These N-S differences in dissolved 231Paxs were attributed to the different origins and scavenging history of the deep Pacific waters flowing across Drake Passage. Here at North, radionuclides-rich deep water originates from the Central Pacific, while at South, deep water derives from the Southern Pacific in which the observed low radionuclides concentrations are attributed to high opal abundance.
    South of the Drake Passage, high dissolved and particulate activities of 230Th and 232Th confirmed the intrusion of 230Th-rich Weddell Sea Deep Water (WSDW) close to the Antarctic Peninsula.
    Sprache Englisch
    Erscheinungsverlauf 2010-9999
    Umfang Online-Ressource
    Verlag PANGAEA - Data Publisher for Earth & Environmental Science
    Erscheinungsort Bremen/Bremerhaven
    Dokumenttyp Buch ; Online
    Anmerkung This dataset is supplement to doi:10.1016/j.dsr2.2010.10.040
    DOI 10.1594/PANGAEA.746773
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  8. Buch ; Online: Circulation changes in the Amundsen Basin from 1991 to 2015 revealed from distributions of dissolved 230Th

    Valk, Ole / Rutgers van der Loeff, Michiel M. / Geibert, Walter / Gdaniec, Sandra / Moran, S. Bradley / Lepore, Kate / Edwards, Robert Lawrence / Lu, Yanbin / Puigcorbé, Viena / Casacuberta, Nuria / Paffrath, Ronja / Smethie, William / Roy-Barman, Matthieu

    eISSN: 1812-0792

    2019  

    Abstract: This study provides dissolved and particulate 230 Th and 232 Th results as well as particulate 234 Th data collected during expeditions to the central Arctic Ocean on ARK-XXIX/3 (2015) and ARK-XXII/2 (2007) (GEOTRACES sections GN04 and GIPY11, ... ...

    Abstract This study provides dissolved and particulate 230 Th and 232 Th results as well as particulate 234 Th data collected during expeditions to the central Arctic Ocean on ARK-XXIX/3 (2015) and ARK-XXII/2 (2007) (GEOTRACES sections GN04 and GIPY11, respectively). Constructing a time-series of dissolved 230 Th from 1991 to 2015 enables the identification of processes that control the temporal development of 230 Th distributions in the Amundsen Basin. After 2007, 230 Th concentrations decreased significantly over the entire water column, particularly between 300 m and 1500 m. This decrease is accompanied by a circulation change, evidenced by a concomitant increase in salinity. Potentially increased inflow of water of Atlantic origin with low dissolved 230 Th concentrations leads to the observed depletion in dissolved 230 Th in the central Arctic. Because atmospherically derived tracers (CFC, 3 He/ 3 H) do not reveal an increase in ventilation rate, it is suggested that these interior waters have undergone enhanced scavenging of Th during transit from the Fram Strait and the Barents Sea to the central Amundsen Basin. The 230 Th depletion propagates downward in the water column by settling particles and reversible scavenging. Taken together, the temporal evolution of Th distributions point to significant changes in the large-scale circulation of the Amundsen Basin.
    Thema/Rubrik (Code) 333
    Sprache Englisch
    Erscheinungsdatum 2019-06-14
    Erscheinungsland de
    Dokumenttyp Buch ; Online
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  9. Buch ; Online: Physical oceanography, nutrients, and d18O measured on water bottle samples during POLARSTERN cruise ARK-XXII/2, supplementary data to: Bauch, Dorothea; Rutgers van der Loeff, Michiel M; Andersen, Nils; Torres-Valdes, Sinhue; Bakker, Karel; Abrahamsen, Einar Povl (2011): Origin of freshwater and polynya water in the Arctic Ocean halocline in summer 2007. Progress in Oceanography, 91(4), 482-495

    Bauch, Dorothea / Abrahamsen, Einar Povl / Andersen, Nils / Bakker, Karel / Rutgers van der Loeff, Michiel M / Torres-Valdes, Sinhue

    2011  

    Abstract: Extremely low summer sea-ice coverage in the Arctic Ocean in 2007 allowed extensive sampling and a wide quasi-synoptic hydrographic and d18O dataset could be collected in the Eurasian Basin and the Makarov Basin up to the Alpha Ridge and the East ... ...

    Abstract Extremely low summer sea-ice coverage in the Arctic Ocean in 2007 allowed extensive sampling and a wide quasi-synoptic hydrographic and d18O 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 determining the origin of freshwater in the halocline, fractions of river water and sea-ice meltwater in the upper 150 m were quantified by a combination of salinity and d18O in the Eurasian Basin. Two methods, applying the preformed phosphate concentration (PO*) and the nitrate-to-phosphate ratio (N/P), were compared to further differentiate the marine fraction into Atlantic and Pacific-derived contributions. While PO*-based assessments systematically underestimate the contribution of Pacific-derived waters, N/P-based calculations overestimate Pacific-derived waters within the Transpolar Drift due to denitrification in bottom sediments at the Laptev Sea continental margin.
    Within the Eurasian Basin a west to east oriented front between net melting and production of sea-ice is observed. Outside the Atlantic regime dominated by net sea-ice melting, a pronounced layer influenced by brines released during sea-ice formation is present at about 30 to 50 m water depth with a maximum over the Lomonosov Ridge. The geographically distinct definition of this maximum demonstrates the rapid release and transport of signals from the shelf regions in discrete pulses within the Transpolar Drift.
    The ratio of sea-ice derived brine influence and river water is roughly constant within each layer of the Arctic Ocean halocline. The correlation between brine influence and river water reveals two clusters that can be assigned to the two main mechanisms of sea-ice formation within the Arctic Ocean. Over the open ocean or in polynyas at the continental slope where relatively small amounts of river water are found, sea-ice formation results in a linear correlation between brine influence and river water at salinities of about 32 to 34. In coastal polynyas in the shallow regions of the Laptev Sea and southern Kara Sea, sea-ice formation transports river water into the shelf's bottom layer due to the close proximity to the river mouths. This process therefore results in waters that form a second linear correlation between brine influence and river water at salinities of about 30 to 32. Our study indicates which layers of the Arctic Ocean halocline are primarily influenced by sea-ice formation in coastal polynyas and which layers are primarily influenced by sea-ice formation over the open ocean. Accordingly we use the ratio of sea-ice derived brine influence and river water to link the maximum in brine influence within the Transpolar Drift with a pulse of shelf waters from the Laptev Sea that was likely released in summer 2005.
    Sprache Englisch
    Erscheinungsverlauf 2011-9999
    Umfang Online-Ressource
    Verlag PANGAEA - Data Publisher for Earth & Environmental Science
    Erscheinungsort Bremen/Bremerhaven
    Dokumenttyp Buch ; Online
    Anmerkung This dataset is supplement to doi:10.1016/j.pocean.2011.07.017
    DOI 10.1594/PANGAEA.763451
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  10. Buch ; Online: 230Th, 231Pa, and 10Be in particle size fractions of an opal-rich sediment of the Atlantic Southern Ocean, supplementary data to: Kretschmer, Sven; Geibert, Walter; Rutgers van der Loeff, Michiel M; Schnabel, Christoph; Xu, Sheng; Mollenhauer, Gesine (2011): Fractionation of **230Th, **231Pa, and **10Be induced by particle size and composition within an opal-rich sediment of the Atlantic Southern Ocean. Geochimica et Cosmochimica Acta, 75(22), 6971-6987

    Kretschmer, Sven / Geibert, Walter / Mollenhauer, Gesine / Rutgers van der Loeff, Michiel M / Schnabel, Christoph / Xu, Sheng

    2011  

    Abstract: This study centers on the question: How sensitive are 231Pa/230Th and 10Be/230Th to sediment composition and redistribution? The natural radionuclides 231Pa, 230Th and 10Be recorded in deep sea sediments are tracers for water mass advection and particle ... ...

    Abstract This study centers on the question: How sensitive are 231Pa/230Th and 10Be/230Th to sediment composition and redistribution? The natural radionuclides 231Pa, 230Th and 10Be recorded in deep sea sediments are tracers for water mass advection and particle fluxes. We investigate the influence of oceanic particle composition on the element adsorption in order to improve our understanding of sedimentary isotope records. We present new data on particle size specific 231Pa and 10Be concentrations. An additional separation step, based on settling velocities, led to the isolation of a very opal-rich phase. We find that opal-rich particles contain the highest 231Pa and 10Be concentrations, and higher 231Pa/230Th and 10Be/230Th isotope ratios than opal-poor particles. The fractionation relative to 230Th induced by the adsorption to opal-rich particles is more pronounced for 231Pa than for 10Be. We conclude that bulk 231Pa/230Th in Southern Ocean sediments is most suitable as a proxy for past opal fluxes. The comparison between two neighboring cores with rapid and slow accumulation rates reveals that these isotope ratios are not influenced significantly by the intensity of sediment focusing at these two study sites. However, a simulation shows that particle sorting by selective removal of sediment (winnowing) could change the isotope ratios. Consequently, 231Pa/230Th should not be used as paleocirculation proxy in cases where a strong loss of opal-rich material due to bottom currents occurred.
    Sprache Englisch
    Erscheinungsverlauf 2011-9999
    Umfang Online-Ressource
    Verlag PANGAEA - Data Publisher for Earth & Environmental Science
    Erscheinungsort Bremen/Bremerhaven
    Dokumenttyp Buch ; Online
    Anmerkung This dataset is supplement to doi:10.1016/j.gca.2011.09.012
    DOI 10.1594/PANGAEA.759976
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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