Search

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 G. oceanica, H. carteri and F. profunda are characteristic of the strength of the northward flowing warm California Counter Current, (ii) the two species G. ericsonii and G. muellerae are associated with the cold equatorward flowing California Current, (iii) and E. huxleyi 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 G. oceanica and H. carteri are associated with warm ENSO events, G. muellerae responds to warm PDO events and the abundance of G. ericsonii increases during cold PDO events. Morphometric parameters measured on E. huxleyi, G. muellerae and G. oceanica indicate increasing coccolithophore shell carbonate mass from ∼ 1917 until 2004 concomitant with rising pCO2 and sea surface temperature in the region of the SBB. [ABSTRACT FROM AUTHOR]

Abstract: A new piston core from Santa Barbara Basin, California provides evidence of the timing, magnitude, and character of deglaciation, including evidence of warming prior to Termination IA. IMAGES Site MD02-2503 (570m water depth) consists of intermittently laminated hemipelagic sediments extending to Interstadial (D/O) event 6 (∼34ka), that accumulated at ∼135cm/ka. During the deglacial episode (16.75–10ka), δ 18O values decreased by 3.2‰ in the planktonic species Globigerina bulloides, indicating a total warming of 8–9°C recorded by surface-dwelling foraminifera (inferred by removing the 1‰ influence of ice volume change). Similarly, benthic species (Bolivina argentea and Uvigerina peregrina) record a 1.65‰δ 18O decrease across the deglacial, interpreted as a 2–3°C warming at upper intermediate depths. δ 18O values of both planktonic and benthics indicate that surface and intermediate waters began to warm ∼2ka prior to Termination IA, beginning at ∼16.5ka. Intermediate water warming exhibits similar structure and synchronous timing with surface waters. These findings are consistent with a growing number of records from around the globe that exhibit pre-Bølling warming prior to Termination IA, and extends the record of such processes to the northern Pacific. [Copyright &y& Elsevier]