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To estimate Holocene changes in organic carbon mass accumulation rates (Corg MARs) in the southeastern Swedish Baltic Sea, two sediment cores were studied in combination with biogeochemical modelling. Prior to 11 300 cal. BP, Corg MARs were extremely low, indicating low organic matter production on the catchment of the Baltic Ice Lake. Following a brief regression, the Ancylus Lake stage occurred between 11 100 and 9800 cal. BP. Corg MARs increased substantially during this period because of enhanced washing in of terrestrial organic matter, when boreal forests were initially established. The prominent marine stage, known as the Littorina transgression between 8500 and 3000 cal. BP, is marked by a minor increase in Corg MARs. Our modelling reveals a changing terrestrial organic carbon input between 100 and 1000 g/m² per yr that accounts for 30–80% of total organic carbon in sediments of the southeastern Swedish Baltic Sea, with maximum values (c. 20 X 10³g/m² per yr) occurring during the Bronze/Iron Age transition at about 3000 cal. BP. Corg MAR in the entire Baltic basin is estimated at 3.01 X 106 t/yr during the pre-industrial Holocene, comparable with other large inland water bodies. Regardless of the source of carbon, our data indicate that the Baltic basin is an important sedimentary reservoir for organic carbon storage and thus should be included in accounting for global terrestrial carbon cycling during the pre-industrial Holocene. [ABSTRACT FROM AUTHOR]

Integrated palaeoecological studies of two fiord sediment sequences in the province of Blekinge, SE Sweden, covering the time span 11,000–5000 cal BP, reveal the timing and the environment for the Ancylus Lake/Littorina Sea transition 9800–8500 cal BP. The first ingression of saline water into the Baltic Sea through the Danish Straits occurred earlier than formerly assumed. New evidence, particularly mineral magnetic and palaeobotanical analyses, demonstrate that on the general trend of the eustatically caused Littorina transgression several minor fluctuations of the water level can be identified between 8500 and 5000 cal years BP. A distinct regression phase around 8100 cal BP is correlated with the Greenland ice-core cold event dated to 8200 ice-core years BP. This is described as a regional climatic catastrophe for the Baltic Sea region. The coastal stratigraphy is compared with the offshore stratigraphy earlier studied. A tentative shore displacement curve for Early and Middle Holocene is presented. [Copyright &y& Elsevier]

Dating the transgression and subsequent regression in marginal basins of the southeastern Swedish Baltic Sea provides a new perspective of global ice-volume changes and the isostatic adjustment of the mantle after the retreat of the Scandinavian Ice Sheet from this area. Superimposed upon a smooth pattern of local sea-level rise, acceleration occurred ca. 7600 calibrated (cal) yr B.P., evidenced as a nearly synchronous flooding in six elevated basins ranging from 3.0 to 7.2 m above present sea level. We ascribe this rapid local sea-level rise of ∼4.5 m to a sudden increase in ocean mass, most likely caused by the final decay of the Labrador sector of the Laurentide Ice Sheet. The subsequent monotonic fall of local sea level from ca. 6500 cal yr B.P. to the present is mainly an expression of the slow isostatic adjustment of the mantle. [ABSTRACT FROM AUTHOR]