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  • Elsevier  (4)
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  • 1
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    Chronology of the Holocene transgression at the North Siberian margin (2001)
    Elsevier
    In:  Global and Planetary Change, 31 (1-4). pp. 125-139.
    Details
    Publication Date: 2019-09-23
    Description: To establish a chronology of the Holocene transgression in Arctic Siberia, a total of 14 sediment cores from the Laptev Sea continental slope and shelf were studied covering the water depth range between 983 and 21 m. The age models of the cores were derived from 119 radiocarbon datings, which were all analyzed on marine biogenic calcite (mainly bivalve shells). The oldest shell sample was found at the slope and dates back to about 15.3 cal. ka, indicating that the time interval investigated starts prior to the onset of the meltwater pulse 1A (similar to 14.2 cal. ka) when global sea-level rose dramatically. The inundation history was reconstructed mainly on the basis of major changes in average sedimentation rates (ASR), but also other sedimentological parameters were incorporated. A diachronous reduction in ASR from the outer to the inner shelf region is recognized, which was related to the southward migration of the coastline as the primary sediment source. We estimate that the flooding of the 50-, 43-, and 31-m isobaths was completed by approximately 11.1, 9.8, and 8.9 cal. ka, and that Holocene sea-level highstand was approached near 5 cal. ka. Between these time intervals, sea level in the Laptev Sea rose by 5.4, 13.3, and 7.9 mm/year, respectively.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/S0921-8181(01)00116-3
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
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    Stable oxygen and carbon isotopes in modern benthic foraminifera from the Laptev Sea shelf: implications for reconstructing proglacial and profluvial environments in the Arctic (2004)
    Elsevier
    In:  Marine Micropaleontology, 51 (3-4). pp. 285-300.
    Details
    Publication Date: 2017-06-21
    Description: Measurements of δ18O and δ13C isotopes in three benthic foraminiferal species from surface sediments of the eastern Laptev Sea are compared to water δ18O values and δ13C values of dissolved inorganic carbon (DIC). Samples investigated originate from two environmentally contrasting core locations, which are influenced by riverine freshwater runoff to a varying degree. At the river-distal site, located within relatively stable marine conditions on the outer shelf, Elphidiella groenlandica, Haynesina orbiculare and Elphidium excavatum forma clavata show a positive specific offset of 1.4‰, 1.5‰ and 1‰, respectively, in their δ18O values relative to the expected value for inorganic calcite precipitated under equilibrium conditions. At the site close to the Lena River confluence, with enhanced seasonal hydrographic contrasts, calculated δ18O offsets in E. groenlandica and in H. orbiculare remain about the same whereas E. e. clavata displays a distinctly negative offset of −1.8‰. The δ18O variation in E. e. clavata is interpreted as a vital effect, a finding which limits the potential of this species for reconstructing freshwater-influenced shelf paleoenvironments on the basis of oxygen isotopes. This interpretation gains support when comparing foraminiferal δ13C with the δ13CDIC of the water. While some of the difference in the carbonate δ13C seems to be controlled by a riverine-related admixture of DIC, clearly defined δ13C ranges in each of the three foraminifera at the river-proximal site shows that also the carbon isotopic signature in E. e. clavata is particularly affected by environmental factors.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.marmicro.2004.01.002
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
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    Linkage of Arctic atmospheric circulation and Siberian shelf hydrography: a proxy validation using δ18O records of bivalve shells (2005)
    Elsevier
    In:  Global and Planetary Change, 48 (1-3). pp. 175-186.
    Details
    Publication Date: 2017-09-13
    Description: High resolution oxygen isotope profiles of aragonitic bivalve shells (Astarte borealis) collected alive in different years are used to trace hydrographical changes on the Laptev Sea shelf, which are mainly forced by changes in riverine freshwater discharge and arctic atmospheric circulation patterns. By merging individual isotope profiles, a high resolution time series of relative changes in bivalve δ18O is obtained for the eastern Laptev Sea for the period 1969 to 1998. The resulting pattern in the δ18O time series reflects seasonal bottom-water salinity changes in the Laptev Sea, which is dominated by the peak input of freshwater discharged by the Lena River onto the Laptev Sea shelf during summer. The relative changes in summer bottom-water salinity, deduced from the δ18O values in the bivalves and the discharge anomaly of the Lena River, show a significant negative correlation. It is therefore suggested that the annual and subdecadal variations of the riverine freshwater and its influence on the shelf hydrography are imprinted in the bivalve shells. Moreover, we note that extreme summer precipitation anomalies in the Lena River catchment area affect the river discharge characteristics, events which are detectable in the δ18O time series. This all implies that δ18O records of bivalve shells have the potential to build long-term records of atmospheric-forced changes in arctic circulation.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.gloplacha.2004.12.012
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
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    Holocene hydrographical change in the eastern Laptev Sea (Siberian Arctic) recorded in delta〈sup〉18〈/sup〉O profiles of bivalve shells (2004)
    Elsevier
    In:  Quaternary Research, 61 (1). pp. 32-41.
    Details
    Publication Date: 2016-09-19
    Description: Oxygen isotope profiles along the growth axis of fossil bivalve shells of Macoma calcarea were established to reconstruct hydrographical changes in the eastern Laptev Sea since 8400 cal yr B.P.. The variability of the oxygen isotopes (δ18O) in the individual records is mainly attributed to variations in the salinity of bottom waters in the Laptev Sea with a modern ratio of 0.50‰/salinity. The high-resolution δ18O profiles exhibit distinct and annual cycles from which the seasonal and annual salinity variations at the investigated site can be reconstructed. Based on the modern analogue approach oxygen isotope profiles of radiocarbon-dated bivalve shells from a sediment core located northeast of the Lena Delta provide seasonal and subdecadal insights into past hydrological conditions and their relation to the Holocene transgressional history of the Laptev Sea shelf. Under the assumption that the modern relationship between δ18Ow and salinity has been constant throughout the time, the δ18O of an 8400-cal-yr-old bivalves would suggest that bottom-water salinity was reduced and the temperature was slightly warmer, both suggesting a stronger mixture of riverine water to the bottom water. Reconstruction of the inundation history of the Laptev Sea shelf indicates local sea level ∼27 m below present at this time and a closer proximity of the site to the coastline and the Lena River mouth. Due to continuing sea level rise and a southward retreat of the river mouth, bottom-water salinity increased at 7200 cal yr B.P. along with an increase in seasonal variability. Conditions comparable to the modern hydrography were achieved by 3800 cal yr B.P.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.yqres.2003.09.003
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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