Ostracod palaeoecology and environmental change in the Laptev and Kara seas (Siberian Arctic) during the last 18 000 years.

Stepanova, Anna, Taldenkova, Ekaterina and Bauch, Henning A. (2012) Ostracod palaeoecology and environmental change in the Laptev and Kara seas (Siberian Arctic) during the last 18 000 years. Boreas, 41 (4). pp. 557-577. DOI 10.1111/j.1502-3885.2012.00254.x.

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Abstract

Fossil ostracod assemblages were investigated in five AMS 14 C-dated cores from various water depths of the Laptev and Kara seas ranging from the upper continental slope (270?m) to the present-day shelf depth (40?m). Six fossil assemblages were distinguished. These represent the varying environmental conditions at the North Siberian continental margin since about 18?ka. In the cores from the shelf the ostracod assemblages reflect the gradual transition from an estuarine brackish-water environment to modern marine conditions since 12.3?ka, as induced by the regional early Holocene transgression. The core from the upper continental slope dates back to c. 17.6?ka and contains assemblages that are absent in the shelf cores. The assemblage older than 10?ka stands out as a specific community dominated by relatively deep-water Arctic and North Atlantic species that also contains euryhaline species. Such an assemblage provides evidence for past inflows of Atlantic-derived waters from as early as c. 17.2?ka, probably facilitated by upwelling in coastal polynyas, and a considerable riverine freshwater influence with enhanced surface water stratification owing to the proximity of the palaeocoastline until early Holocene times. In all studied cores, relative increases in euryhaline species dominant in the inner-shelf regions are recorded in the midlate Holocene sediments (<7?ka), which otherwise already contain modern-like ostracod assemblages with relatively deep-water species. This observation suggests euryhaline species to be largely sea-ice- and/or iceberg-rafted and therefore may provide evidence for a climate cooling trend.

Document Type: Article
Additional Information: WOS:000309394800004
Keywords: ICE-SHEET HISTORY; CAL YR BP; SEDIMENTARY RECORD; STABLE-ISOTOPES; PALEOENVIRONMENTAL IMPLICATIONS; QUATERNARY PALEOCEANOGRAPHY; CONTINENTAL-MARGIN; OCEAN CIRCULATION; NORTHERN BARENTS; ATLANTIC WATER
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1111/j.1502-3885.2012.00254.x
ISSN: 0300-9483
Projects: Otto Schmidt Laboratory, Laptev Sea System, Polynya
Date Deposited: 02 Nov 2012 09:47
Last Modified: 24 Jan 2017 07:56
URI: http://oceanrep.geomar.de/id/eprint/19084

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