California Current System response to late Holocene climate cooling in southern California

Abstract

New Holocene high-resolution planktonic fora-miniferal assemblage data from Santa Barbara Basin, California documents variability in ocean circulation as the California Current System responded to millennial-scale climate change during late Holocene climatic cooling. Climatic variability increased at 4 ka when a series of extreme cool events, (notably at 2.2, 1.5 and 0.8 ka) associated with glacial advance in the Pacific Northwest punctuated the predominantly warm Holocene. Simultaneously high subtropical species abundance suggests increased interannual variability (El Niño frequency/severity) or greater seasonality during the late Holocene. Planktonic foraminiferal assemblages indicate that the magnitudes of climatic shifts were greatest after 1.5 ka during an interval of extreme terrestrial hydrological variability in western North America and that the coolest interval of the Holocene in Santa Barbara Basin was coincident with the Little Ice Age. Copyright 2008 by the American Geophysical Union.