https://dx.doi.org/10.1038/ncomms10284">
 

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Abstract

Marine algae are instrumental in carbon cycling and atmospheric carbon dioxide (CO2) regulation. One group, coccolithophores, uses carbon to photosynthesize and to calcify, covering their cells with chalk platelets (coccoliths). How ocean acidification influences coccolithophore calcification is strongly debated, and the effects of carbonate chemistry changes in the geological past are poorly understood. This paper relates degree of coccolith calcification to cellular calcification, and presents the first records of size-normalized coccolith thickness spanning the last 14 Myr from tropical oceans. Degree of calcification was highest in the low-pH, high-CO2 Miocene ocean, but decreased significantly between 6 and 4 Myr ago. Based on this and concurrent trends in a new alkenone ɛp record, we propose that decreasing CO2 partly drove the observed trend via reduced cellular bicarbonate allocation to calcification. This trend reversed in the late Pleistocene despite low CO2, suggesting an additional regulator of calcification such as alkalinity.

Department

Earth Sciences

Publication Date

1-14-2016

Journal Title

Nature Communications

Publisher

Springer Nature

Digital Object Identifier (DOI)

https://dx.doi.org/10.1038/ncomms10284

Document Type

Article

Comments

This is an article published by Springer Nature in Nature Communications in 2016, available online: https://dx.doi.org/10.1038/ncomms10284

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