Pollen–spore distribution in the surface sediments of the western Bohai Sea, China

Abstract Eighty-six seafloor surface sediment samples from the western Bohai Sea were analyzed palynologically to understand the distribution pattern and transport paths of pollen and spores. The results reveal that the pollen assemblages are dominated by arboreal pollen, which accounts for an average of 52% and mainly includes Pinus , deciduous Quercus , Carpinus , Betula , Nitraria , Castanea , and Ulmus . The pollen percentages of herbaceous taxa reach an average of 25%, mostly represented by Chenopodiaceae, Artemisia , Gramineae, Liliaceae, Polygonum , Typha , and Cyperaceae. The fern spores are mostly Selaginella , Osmunda , Triletes, and Monoletes. The distribution characteristic of pollen and spores implies that the pollen assemblages correspond well with the watershed vegetation. Variation in the pollen assemblages in different parts of the marine area could reflect differences in local vegetation, especially the vegetation along the inflowing rivers. The spatial distribution of pollen assemblages further suggests that the discharge from the Yellow River and Luanhe River has a great contribution to the pollen inputs into the western Bohai Sea. Pollen concentrations are lower in the nearshore sea area (water depth  Pinus were mainly transported by winds and ocean currents, and fern spores mainly by river flows and ocean currents. The latter two types were mostly concentrated in relatively deeper water area.