Extreme Oscillations of the Sea Level in the Laptev Sea

Author(s):  
I. Ashik ◽  
Y. Dvorkin ◽  
Y. Vanda
Keyword(s):  
arktos ◽  
2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Volker Klemann ◽  
Birgit Heim ◽  
Henning A. Bauch ◽  
Sebastian Wetterich ◽  
Thomas Opel

2019 ◽  
Vol 59 (3) ◽  
pp. 433-448
Author(s):  
T. S. Klyuvitkina ◽  
Ye. I. Polyakova

On the basis of aquatic palynomorph assemblages in sediment cores obtained from the eastern Laptev Sea shelf, major phases of environmental change associated with the last postglacial global sea-level rise can be recognized for the time since 17.5 calendar years BP (cal. ka). It is shown that in the time interval of 17.5–13.0 cal. ka in the western part of the sea there was a very cold-water sea basin with permanent sea-ice cover, 12.3–11.2 cal. ka the outer shelf were characterized by increased precipitation of river-loaded matter in a river-proximal environment of Anabara and Khatanga rivers, and the period of 11.2–7.0 cal ka was marked by enhanced influence of Atlantic water at the Laptev Sea continental margin. Modern-like environments were established in this part of the sea approximately 7.0 cal. ka.


2004 ◽  
Vol 61 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Thomas Mueller-Lupp ◽  
Henning A. Bauch ◽  
Helmut Erlenkeuser

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.


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3511
Author(s):  
Elena Gershelis ◽  
Andrey Grinko ◽  
Irina Oberemok ◽  
Elizaveta Klevantseva ◽  
Natalina Poltavskaya ◽  
...  

Global warming in high latitudes causes destabilization of vulnerable permafrost deposits followed by massive thaw-release of organic carbon. Permafrost-derived carbon may be buried in the nearshore sediments, transported towards the deeper basins or degraded into the greenhouse gases, potentially initiating a positive feedback to climate change. In the present study, we aim to identify the sources, distribution and degradation state of organic matter (OM) stored in the surface sediments of the Laptev Sea (LS), which receives a large input of terrestrial carbon from both Lena River discharge and intense coastal erosion. We applied a suite of geochemical indicators including the Rock Eval parameters, traditionally used for the matured OM characterization, and terrestrial lipid biomarkers. In addition, we analyzed a comprehensive grain size data in order to assess hydrodynamic sedimentation regime across the LS shelf. Rock-Eval (RE) data characterize LS sedimentary OM with generally low hydrogen index (100–200 mg HC/g TOC) and oxygen index (200 and 300 CO2/g TOC) both increasing off to the continental slope. According to Tpeak values, there is a clear regional distinction between two groups (369–401 °C for the inner and mid shelf; 451–464 °C for the outer shelf). We suggest that permafrost-derived OM is traced across the shallow and mid depths with high Tpeak and slightly elevated HI values if compared to other Arctic continental margins. Molecular-based degradation indicators show a trend to more degraded terrestrial OC with increasing distance from the coast corroborating with RE results. However, we observed much less variation of the degradation markers down to the deeper sampling horizons, which supports the notion that the most active OM degradation in LS land-shelf system takes part during the cross-shelf transport, not while getting buried deeper.


2001 ◽  
Vol 12 (2) ◽  
pp. 191-202 ◽  
Author(s):  
Nikolai N. Romanovskii ◽  
Hans-W. Hubberten
Keyword(s):  

1997 ◽  
Vol 17 (2) ◽  
pp. 205-233 ◽  
Author(s):  
H. Eicken ◽  
E. Reimnitz ◽  
V. Alexandrov ◽  
T. Martin ◽  
H. Kassens ◽  
...  

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