Last Interglacial (MIS 5e) sea surface hydrographic conditions in coastal southern California based on dinoflagellate cysts

The first high resolution record of dinoflagellate cysts ∼110–155 kyr over Termination II and the Last Interglacial in Santa Barbara Basin, California from ODP Hole 893A details a complex paleoceanographic history. Variation cyst relative abundances, concentrations, diversity reflects climatic ocean circulation changes, assemblages are used to make qualitative reconstructions sea surface temperature (SST) annual primary productivity. dominance heterotrophic Brigantedinium spp. throughout section indicates an important influence coastal upwelling on basin. Based assemblages, five zones identified, which approximately correspond marine isotope stage boundaries their associated changes SST level. Cooler intervals, MIS 6 5d, characterized by cold-water indicator species Selenopemphix undulata whereas thermophilic taxon Spiniferites mirabilis characterizes warm 5e. In contrast other studies Pacific, data exhibits one two-thousand-year cooling event ∼129 that correlates level still-stand two-step deglaciation. A significant increase concentrations latest 5e implies enhanced production due increased seasonal warm, nutrient rich waters entering basin after stabilizes near modern levels. hydrological evolution signal is similar development Holocene but sustained presence across SSTs were higher than conditions.