Previous palynological studies of the Caspian–Black Sea–Mediterranean corridor primarily focused on pollen and spores for paleoecological and chronostratigraphic studies. Until recently, there has been less emphasis on the nonpollen palynomorphs, such as dinoflagellate cysts, algal and fungal spores, and animal remains. New studies of nonpollen palynomorphs in land-locked seas, estuaries, and lakes reported here indicate that they are important markers of salinity, nutrient loading, and human activity, including ballast discharge, farming, and soil erosion. We describe the nonoxidative laboratory processing methods necessary to extract nonpollen palynomorphs from marine- and brackish-water sediment samples. We list 48 nonpollen palynomorphs taxa from 37 surface sediments (including the past millennium) for cores along the salinity gradient from <16‰ off the Danube Delta to >39‰ in the Aegean, Mediterranean, and Red Seas, for two Crimean saline lakes, the Caspian and Aral Seas, and for lakes in Iran and Kazakhstan. The main nonpollen palynomorphs taxa are illustrated and listed systematically to provide a baseline for future collaborative studies among Black Sea corridor palynologists. We outline the biological affinities of some nonpollen palynomorphs and discuss the initial results of the study in terms of what nonpollen palynomorphs may reveal about the history of the salinity in the Black Sea corridor and the impact of humans on soil erosion, plankton production, and harmful algal blooms.

An accurate chronology for the exchange of aquatic species between water basins is important for paleoenvironmental reconstruction on both regional and continental scales. During the early Holocene, the range of zebra mussels, Dreissena polymorpha , was limited to the Black, Azov, Caspian, and Aral Seas, as well as the estuaries and lower and middle reaches of the Pontic-Caspian rivers. We present new findings that challenge the currently held view that this species migrated into the Baltic Sea watershed during the early 1800s through the canals joining the tributaries of rivers that drain into the Black and Baltic Sea basins. Geological investigations along the southeast Baltic Sea coast (Curonian and Vistula spits and lagoons) have uncovered shells of D. polymorpha that yielded radiocarbon ages older than 1000 radiocarbon yr B.P. We propose two scenarios to explain the new radiocarbon dates for D. polymorpha . The first scenario involves an anomalously large reservoir effect—as large as 600–800 yr—however, several lines of evidence cast doubt upon the validity of such a large reservoir correction. The second scenario that might explain the old zebra mussel ages is the earlier arrival of Dreissena polymorpha into the Baltic region. Natural exchange may have been facilitated by the proximity of the tributaries draining the Pontic and Baltic watersheds. Human-mediated transport is also considered in association with Viking voyages from the Baltic to the Black and Caspian Seas between A.D. 800 and 1000, and the riverine trade exchange during the Lithuanian expansion into the Pontic steppe in subsequent centuries. It is likely that both scenarios played a role, with implications for late Holocene biogeography and paleoecology of the Pontic-Caspian and Baltic basins.