Short- and long-term environmental change in the Laptev Sea/Siberian Arctic during the Holocene / Kurz- und langfristige Umweltveränderungen in der Laptev-See (sibirische Arktis) während des Holozäns

• Main Author: Müller-Lupp, Thomas
• Format: Report
• Language: English
• Published: AWI 2002
• Subjects: Arctic; Laptev Sea; Arktis; Arktis*; Ice; laptev; permafrost
• Online Access: https://oceanrep.geomar.de/id/eprint/6409/; https://oceanrep.geomar.de/id/eprint/6409/1/BerPolarforsch2002424.pdf; https://oceanrep.geomar.de/id/eprint/6409/7/Diss_M%C3%BCller-Lupp_T_2001.pdf

Given the variability of seasonal, annual, and in particular langer time-scales, the dispersal and fate of the river discharge and its influence on the hydrographical and sedimentological settings are the central tasks in understanding the Holocene history of the Laptev Sea shelf. The main goal of this study was to investigate short- and long-term environmental changes in the strongly coupled land-shelf system of the Laptev Sea using isotopic evidence in sediments and biogenic carbonates. In order to trace the modern spatial distribution of terrestrial organic matter, which is strongly affected by the riverine input and the thermal erosion of the ice-rich permafrost coast, stable carbon isotope ratios of total organic carbon in surface sediments were analyzed. The stable carbon isotope composition of surface sediments reveal a dominant impact of terrestrial organic matter on the modern depositional environment of the Laptev Sea shelf with distinct south to north and east to west gradients. Based on downcore 8 13Carg records in radiocarbon-dated sediment cores the spatial and temporal deposition of terrestrial organic matter during the past 12.7 ka is specified and can be related to depositional changes which occurred after the last glacial maximum when this region became flooded due to a global rising sea level. The major changes in the deposition of terrestrial organic matter occurred between 11 and 7 ka BP and comprise the main phase of the southward retreat of the coastline and river depocenters due to the postglacial sea level rise. Stable oxygen and carbon isotope profiles from recent and fossil bivalve shells were investigated in order to trace modern and past hydrographical conditions and their changes during the postglacial history of the Laptev Sea. The serial dissection of bivalve shell valves along their growth axis from the umbo towards the ventral margin provides an isotopic record of hydrographical and physiological changes during the life of the individual specimen. The oxygen isotopic profiles of ...