Recent dinoflagellate cysts in a transect from the Falkland trough to the Weddell Sea, Antarctica

Dinoflagellate cyst analysis has been completed on core-top samples that form a transect from the area of the Falkland Islands to the Weddell Sea, Antarctica. This study is the first to document the distribution of the Recent dinoflagellate cyst thanatocoenosis in the area. All the dinoflagellate cysts recovered are described and at least two species, Dalella chathamense and Selenopemphix antarctica, are recognized as endemic to the southern hemisphere from the results of this study and from previous research. Data presented here reveal a clear latitudinal trend in the cyst distribution such that subdivision into two domains is possible. The first, to the south of 60°S, is characterized by low numbers of cysts, low diversity and the presence of Impagidinium pallidum, Algidasphaeridium? minutum, Pentapharsodinium dalei?, round brown Protoperidinium cysts and Selenopemphix antarctica. The second, to the north of 60°S, is characterized by richer assemblages, higher species diversity and the presence of Dalella chathamense, Impagidinium sphaericum, Nematosphaeropsis labyrinthus and high numbers of Selenopemphix antarctica. This division of the cyst assemblages coincides approximately with the northern winter limit of sea-ice and demonstrates the potential of dinoflagellate cyst analysis in the elucidation of the palaeoceanography of the area using this criterion.