@article {muller_temperature_2021,
	title = {Temperature Induced Physiological Reaction Norms of the Coccolithophore Gephyrocapsa oceanica and Resulting Coccolith Sr/Ca and Mg/Ca Ratios},
	journal = {Frontiers in Earth Science},
	volume = {9},
	year = {2021},
	pages = {273},
	abstract = {Coccolithophores are one of the major contributors to the pelagic production of calcium carbonate and their fossilized remains are a key component of the biogeochemical cycles of calcium (Ca), magnesium (Mg), and other divalent cations present in the intracellular precipitated calcitic structures (coccoliths). The geochemical signature of coccoliths (e.g., Sr/Ca and Mg/Ca ratios) is used as paleoproxy to reconstruct past environmental conditions and to understand the underlying physiological precipitation kinetics. Here, we present the elemental fractionation of Sr and Mg in calcite of the coccolithophore Gephyrocapsa oceanica from controlled laboratory experiments applying an extended temperature gradient (12 to 27{\textdegree}C). The physiological reaction norm of G. oceanica, in terms of growth rate, exhibited optimum behavior while the partition coefficient of Sr (DSr) was linearly correlated with temperature and DMg indicated no specific trend. Our results indicate: (1) a presumably secondary physiological control of DSr, and (2) the importance of calibrating coccolithophore-based proxies using experiments that include the full physiological reaction norms (i.e., a possible non-linear response) to environmental drivers (e.g., temperature, salinity, and pH, etc.). The presented results contribute to an improved understanding of the underlying physiological kinetics involved in regulating coccolith elemental fractionation and give additional implications for designing future laboratory experiments to calibrate and apply coccolithophore based paleoproxies on the fossil sediment record.},
	keywords = {rcc, RCC1303},
	issn = {2296-6463},
	doi = {10.3389/feart.2021.582521},
	url = {https://www.frontiersin.org/article/10.3389/feart.2021.582521},
	author = {M{\"u}ller, Marius N. and Blanco-Ameijeiras, Sonia and Stoll, Heather M. and M{\'e}ndez-Vicente, Ana and Lebrato, Mario}
}
@article {Bolton2016,
	title = {Decrease in coccolithophore calcification and CO2 since the middle Miocene},
	journal = {Nature Communications},
	volume = {7},
	year = {2016},
	note = {tex.mendeley-tags: 2016,rcc},
	pages = {10284},
	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 ep 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. 1},
	keywords = {2016, rcc},
	issn = {2041-1723},
	doi = {10.1038/ncomms10284},
	url = {http://www.nature.com/doifinder/10.1038/ncomms10284},
	author = {Bolton, Clara T. and Hern{\'a}ndez-S{\'a}nchez, Mar{\'\i}a T. and Fuertes, Miguel-{\'A}ngel and Gonz{\'a}lez-Lemos, Sa{\'u}l and Abrevaya, Lorena and M{\'e}ndez-Vicente, Ana and Flores, Jos{\'e}-Abel and Probert, Ian and Giosan, Liviu and Johnson, Joel and Stoll, Heather M.}
}
