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Eemian and Holocene sea-surface conditions in the southern Black Sea: Organic-walled dinoflagellate cyst record from core 22-GC3
ISSN
1872-6186
0377-8398
Date Issued
2013
Author(s)
Marret, Fabienne
Fleitmann, Dominik
Arz, Helge W.
Nowaczyk, Norbert
DOI
10.1016/j.marmicro.2013.02.001
Abstract
In order to compare the sea-surface conditions in the Black Sea during the Holocene and Eemian, sapropelic parts of marine core 22-GC3 (42 degrees 13.53'N/36 degrees 29.55'E, 838 m water depth) were studied for organic-walled dinoflagellate cyst content. The record shows a change from freshwater/brackish assemblages (Pyxidinopsis psilata, Spiniferites cruciformis, and Caspidinium rugosum) to more marine assemblages (Lingulodinium machaerophorum and Spiniferites ramosus complex) during each interglacial, due to the inflow of saline Mediterranean water. The lacustrine-marine transitions in 22-GC3 occurred at similar to 8.3 cal kyr BP during the early Holocene and similar to 128 kyr BP during the early Eemian, slightly later compared to the onset of interglacial conditions on the adjacent land. Dinoflagellate cyst assemblages reveal higher sea-surface salinity (similar to 28-30) (e.g. Spiniferites pachydermus, Bitectatodinium tepikiense, and Spiniferites mirabilis) around similar to 126.5-121 kyr BP in comparison to the Holocene (similar to 15-20) as well as relatively high sea-surface temperature (e.g. Tuberculodinium vancampoae, S. pachydermus, and S. mirabilis) especially at similar to 127.6-125.3 kyr BP. Establishment of high sea-surface salinity during the Eemian correlates very well with reconstructed relatively high global sea-level and is explained as a combined effect of increased Mediterranean supply and high temperatures at the beginning of the last interglacial. The observed changes in the dinocyst record highlight the importance of nutrients for the composition of the Eemian and Holocene dinocyst assemblages. (C) 2013 Elsevier B.V. All rights reserved.