Sedimentary archives from the Baltic Sea provide a unique opportunity to investigate the ecology of dinoflagellates and other palynomorphs that lived in this enclosed sea. The Baltic Sea has experienced substantial variations in sea surface salinity (Widerlund and Andersson, 2011) throughout its history together with variations in bottom water hypoxia (Zillén et al. 2008). The Baltic Sea started as a fresh-water lake which later became brackish water setting maybe some more here about the different stages. A pilot study funded through the Lund Centre of Carbon Cycle and Climate Interactions (LUCCI, Lund University) is being undertaken on core F80 from the eastern Gotland Basin, within the northern part of the Gotland basin, water depth 181m. Down-core reconstructions of variations in kerogen (palynofacies), dinoflagellate cysts and other non-pollen assemblages are currently being preformed across three intervals comprising organic rich, laminated sediments in core F80.

Palynofacies studies has primarily been developed in connection with oil exploration, but has also been applied on Quaternary sediments. We are examining shifts in palynofacies and non-pollen palynomorphs (sensu Mudie et al. 2011) to further understand temporal changes in dissolved oxygen concentration and energy levels in the water-column, sea surface salinity and temperatures, together with nutrient fluctuations. We will relate these variations to past periods with hypoxic bottom conditions, documented through preservation of laminated sediments. By focusing on the period of human impact (last 2.000 years) and beyond we aim to elucidate the relative importance of various forcing mechanisms e.g. climatic versus anthropogenic during periods of with widespread hypoxia in the Baltic Sea. Preliminary results reveal that the palynological assemblages can be divided into distinct palynofacies intervals characterized by specific assemblages of dinoflagellate cysts, acritarchs and overall kerogen composition. A number of other palynomorphs is encountered in core F80 such as remains from testate amoebae, aquatic tintinnids, arthropods and copepods eggs derived from different types of pelagic copepods.

Mudie, P., Leroy, S.A.G., Marret, F., Gerasimenko, N., Kholeif, S.E.A., Sapelko, T., and Filipova-Marinova. M. (2011): Non-pollen palynomorphs: Indicators of salinity and environmental change in the Caspian-Black Sea-Mediterranean corridor. The Geological Society of America, Special Paper 473, 1-27.

Widerlund, A. and Andersson, P.S. (2011). Late Holocene freshening of the Baltic Sea derived from high-resolution strontium isotope analyses of mollusk shells. Geology 39, 187-190.

 Zillén, L., Conley, D.J., Andrén, T., Andrén, E., and Björck, S. (2008). Past occurrences of hypoxia in the Baltic Sea and the role of climate variability, environmental change and human impact: Earth-Science Reviews 91, 77–92.