Palynological Evidence for Late Quaternary Climate and Marine Productivity Changes Along the California Margin

The sedimentary records of dinoflagellate cysts and foraminiferal organic linings from Ocean Drilling Program Holes 1017E (California Margin) and 893A (Santa Barbara Basin) indicate strong response of marine productivity to major shifts in climate and ocean circulation along the California Margin over the past 42 kyr. Throughout the sequences, dinoflagellate cyst assemblages are dominated by upwelling-related taxa, indicating the continued influence of coastal upwelling on the Margin during the Late Quaternary. The cyst records suggest that marine productivity was enhanced during the Holocene and Bolling, and to a lesser extent, during the Last Glacial Maxima and Dansgaard-Oeschger events, while an apparent reduction in productivity can be seen during the Younger Dryas. Comparison between these two sedimentary records allows us to identify local and regional paleoenvironmental signals. For example, the Allerod manifests itself in the enhancement of local marine productivity in the Santa Barbara Basin compared to a regional signal from the California Margin. Our results also indicate noticeable climate variability during the Holocene in this region. Application of the modern dinoflagellate-cyst assemblage-database from the Northeastern Pacific quantitatively indicates that Holocene August sea-surface temperature, salinity and annual marine productivity varied over dynamic ranges of 13-15°C, 24-33 psu, 200-330 gC m-2 yr-1, respectively.