Coccolithophore response to climate and surface hydrography in Santa Barbara Basin, California, AD 1917–2004

• Main Authors: M. Grelaud, A. Schimmelmann, L. Beaufort
• Format: Article
• Language: English
• Published: Copernicus Publications 2009-10-01
• Series: Biogeosciences
• Online Access: http://www.biogeosciences.net/6/2025/2009/bg-6-2025-2009.pdf
• ISSN: 1726-4170; 1726-4189

The varved sedimentary AD 1917–2004 record from the depositional center of the Santa Barbara Basin (SBB, California) was analyzed with monthly to triannual resolution to yield relative abundances of six coccolithophore species representing at least 96% of the coccolithophore assemblage. Seasonal/annual relative abundances respond to climatic and surface hydrographic conditions in the SBB, whereby (i) the three species <i>G. oceanica</i>, <i>H. carteri</i> and <i>F. profunda</i> are characteristic of the strength of the northward flowing warm California Counter Current, (ii) the two species <i>G. ericsonii</i> and <i>G. muellerae</i> are associated with the cold equatorward flowing California Current, (iii) and <i>E. huxleyi</i> appears to be endemic to the SBB. Spectral analyses on relative abundances of these species show that all are influenced by the El Niño Southern Oscillation (ENSO) and/or by the Pacific Decadal Oscillation (PDO). Increased relative abundances of <i>G. oceanica</i> and <i>H. carteri</i> are associated with warm ENSO events, <i>G. muellerae</i> responds to warm PDO events and the abundance of <i>G. ericsonii</i> increases during cold PDO events. Morphometric parameters measured on <i>E. huxleyi</i>, <i>G. muellerae</i> and <i>G. oceanica</i> indicate increasing coccolithophore shell carbonate mass from ~1917 until 2004 concomitant with rising <i>p</i>CO<sub>2</sub> and sea surface temperature in the region of the SBB.