Spring bloom dinoflagellate cyst dynamics in three eastern sub-basins of the Baltic Sea. (1st April 2017) - Sildever, Sirje
Abstract: Dinoflagellate cyst abundance and species composition were investigated before, during and after the spring bloom in the Gulf of Finland, north-eastern Baltic Proper and Gulf of Riga in order to detect spatial and temporal dynamics. Transport of newly formed cysts by currents was modelled to explore the possible distance travelled by cysts before sedimentation. The cyst community of the spring bloom dinoflagellates was dominated by the cysts of Biecheleria baltica in all basins, despite its marginal value in the planktonic spring bloom community in the Gulf of Riga. Dinoflagellate cyst abundance in the surface sediments displayed temporal dynamics in all basins, however, this appeared to be also influenced by physical processes. The model simulation showed that newly formed cysts are transported around 10–30 km from the point of origin before deposited. The latter suggests that transport of resting stages in the water column significantly affects spatial cyst distribution in the sediments and thus needs to be considered in the interpretation of temporal biological productivity patterns of a water body from cyst proxies. Highlights: Dinoflagellate cyst community dynamics in the eastern Baltic Sea were studied. Distance travelled by the newly formed cysts before sedimentation was modelled. Dinoflagellate cyst communities are influenced by resuspension and transport. The newly formed cysts can travel up to 100 km before deposition. High cyst abundances might not always reflect high cyst production.