Organic carbon distribution and isotopic composition in three records from the eastern Mediterranean Sea during the Holocene

We investigated the distribution of organic carbon (TOG) and bulk organic delta C-13(org) values in two cores from the Aegean Sea and one from the Libyan Sea, eastern Mediterranean Sea (EMS) with a focus on the timing and regional expression of sapropel S-1 deposition in the early Holocene. Our data indicate that the onset of S-1 occurred earlier in the Libyan Sea (similar to 9 8 kyr BP) than in the Aegean Sea (similar to 8 9 kyr BP), implying that dysoxia/anoxia started earlier in the deeper sites of the EMS than in the shallower sites in the Aegean Sea. Accumulation rates of organic matter (OM) during the S-1 period have a clear decreasing gradient from north to south, with higher values in the Aegean Sea and TOG contents higher in the deep basin The three sedimentary sequences exhibit delta C-13(org) values that fall within the range of algal OM (-25 parts per thousand to -20 parts per thousand). Shifts to lighter delta C-13(org) values within sapropel Intervals in the Aegean sites can be interpreted as the result of elevated marine production, enhanced inflow of light terrestrial dissolved inorganic carbon and/or of the shoaling of the pycnocline, along with the presence of a deep chlorophyll maximum (DCM) during the S-1 period (C) 2010 Elsevier Ltd. All rights reserved.