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Little is known about the Neogene marine palynoflora of the Bering Sea. Here, we present the first dinoflagellate cyst and acritarch data for the Pliocene and Lower Pleistocene since the landmark publication of Bujak in Micropalaeontology (1984) based on sediments from Deep Sea Drilling Project Leg 17 in 1971. In 2009, Integrated Ocean Drilling Program (IODP) Leg 323 drilled several new sites in the Bering Sea. IODP Site U1341 (54°2’N, 179°0’E, water depth = 2177 m) is situated on Bowers Ridge, a topographic high that extends 300 km north from the Aleutian Island arc in the deeper part of the Bering Sea (Aleutian Basin).

We analysed samples between 501 and 239 mbsf from the splice of Site U1341 (includes holes U1341A and U1341B). According a preliminary age model this corresponds approximately to the time interval 3.6–1.8 Ma. The dinoflagellate cyst assemblages have low diversity and are dominated by protoperidiniaceans (Trinovantedinium, Brigantedinium, Echinidinium and round brown cysts). Autotrophic dinoflagellate cysts are less abundant, but Impagidinium pallidum, Habibacysta tectata, and specimens of the genus Batiacasphaera can be common constituents of the assemblages.

Acritarchs can dominate the samples, and be up to four times as abundant as dinoflagellate cysts. Cymatiosphaera? invaginata, C.? baffinensis can be particularly common, and species of the genus Lavradosphaera, currently only known from the North Atlantic, have also been identified. Terrestrial palynomorphs include bisaccate pollen, echinate pollen, tetrad pollen, Chenopodiaceae, and both monolete and trilete spores.