Abstract

Within sediments from the central Santa Barbara Basin that date from 1883 to 1992, “round brown” protoperidinioid cysts, characteristic of modern marine upwelling environments dominate the dinocyst associations. With respect to a detrended temperature anomaly curve (DTA) for the northern hemisphere, the proportions of the gonyaulacoid taxa Spiniferites and cysts from ? Alexandrium catenella show significant increases within climatic “warming” and “cooling” intervals respectively. The maximum and peak abundance of the ratio of protoperidinioid “round brown” cysts to Spiniferites occur at the onset and during the 1947 to 1971 “cooling interval” respectively. In contrast, during the “warming interval” of 1905 to 1946, and most prominently since 1972, this ratio is persistently low, with values mostly well below its average. Regionally, a strong and persistent increase in proportions of Spiniferites since the mid-seventies strongly parallels undetrended higher temperatures of both sea surface and air, which is coincident to the onset and duration of a “warm oceanic event” within the Southern California region. The ratio of terrigenous sporomorphs to marine palynomorphs shows a significant positive correlation with regional average amounts of precipitation. Generally, results indicate that even minor global (northern hemisphere) climatic changes may result in significant changes in regional ocean current patterns, which are reflected by prominent changes of dinocyst associations.

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