@article {zhang_isotope_2021,
	title = {An isotope label method for empirical detection of carbonic anhydrase in the calcification pathway of the coccolithophore Emiliania huxleyi},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {292},
	year = {2021},
	pages = {78{\textendash}93},
	abstract = {Coccolithophores are a group of phytoplankton widely distributed in the ocean, which secrete extracellular calcite plates termed coccoliths. Coccoliths have been increasingly employed as an archive for geochemical, ecological and paleoclimate studies in recent years. A robust application of coccolith-based geochemical proxies relies on understanding the carbon acquisition strategies and the pathways of carbon supply for calcification. Carbonic anhydrase (CA) plays important roles in the carbon concentrating mechanism s of aquatic algae and potentially also in calcification. However, it is difficult to independently assess the role of CA in carbon supply for photosynthesis versus calcification. To fill this gap, we explored a new method to detect the CA activity inside coccolithophore. To achieve this, coccolithophores were cultured with oxygen and carbon isotope labeled dissolved inorganic carbon (DIC). By exploiting the different behavior of oxygen and carbon isotopes with (sea)water, this double label method can elucidate the significance of CA activity in the calcification pathway. Application of this method to Emiliania huxleyi shows that CA is present in the calcification pathway, and that there is no significant difference in the CA activity between a high and low CO2 treatment. However, under low CO2 treatment E. huxleyi enhanced the bicarbonate pumping rate on both cell and chloroplast membranes. This novel method could be performed on other species of coccolithophores in the future and have a potential to extend our knowledge on coccolith oxygen isotope vital effects.},
	keywords = {Carbonic anhjydrase, ccm, coccolithophore, Isotopic labelling, rcc, rcc1258},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2020.09.008},
	url = {https://www.sciencedirect.com/science/article/pii/S0016703720305597},
	author = {Zhang, Hongrui and Blanco-Ameijeiras, Sonia and Hopkinson, Brian M. and Bernasconi, Stefano M. and Mejia, Luz Maria and Liu, Chuanlian and Stoll, Heather}
}
@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 {BlancoAmeijeiras2020,
	title = {Influence of temperature and CO 2 on Plasma-membrane permeability to CO 2 and HCO 3 - in the marine haptophytes emiliania huxleyi and calcidiscus leptoporus (prymnesiophyceae)},
	journal = {Journal of Phycology},
	year = {2020},
	note = {tex.mendeley-tags: RCC1130,RCC1258},
	month = {jun},
	pages = {jpy.13017},
	abstract = {Membrane permeabilities to CO2 and HCO3- constrain the function of CO2 concentrating mechanisms that algae use to supply inorganic carbon for photosynthesis. In diatoms and green algae, plasma membranes are moderately to highly permeable to CO2 but effectively impermeable to HCO3-. Here, CO2 and HCO3- membrane permeabilities were measured using an 18O-exchange technique on two species of haptophyte algae, Emiliania huxleyi and Calcidiscus leptoporus, which showed that the plasma membranes of these species are also highly permeable to CO2 (0.006{\textendash}0.02 cm ? s-1) but minimally permeable to HCO3-. Increased temperature and CO2 generally increased CO2 membrane permeabilities in both species, possibly due to changes in lipid composition or CO2 channel proteins. Changes in CO2 membrane permeabilities showed no association with the density of calcium carbonate coccoliths surrounding the cell, which could potentially impede passage of compounds. Haptophyte plasma-membrane permeabilities to CO2 were somewhat lower than those of diatoms but generally higher than membrane permeabilities of green algae. One caveat of these measurements is that the model used to interpret 18O-exchange data assumes that carbonic anhydrase, which catalyzes 18O-exchange, is homogeneously distributed in the cell. The implications of this assumption were tested using a two-compartment model with an inhomogeneous distribution of carbonic anhydrase to simulate 18O-exchange data and then inferring plasma-membrane CO2 permeabilities from the simulated data. This analysis showed that the inferred plasma-membrane CO2 permeabilities are minimal estimates but should be quite accurate under most conditions.},
	keywords = {carbon concentrating mechanism, CO2, haptophyte, membrane, PERMEABILITY, RCC1130, rcc1258},
	issn = {0022-3646},
	doi = {10.1111/jpy.13017},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jpy.13017},
	author = {Blanco-Ameijeiras, Sonia and Stoll, Heather M. and Zhang, Hongrui and Hopkinson, Brian M.},
	editor = {Raven, J.}
}
@article {Blanco-Ameijeiras2016,
	title = {Phenotypic variability in the coccolithophore emiliania huxleyi.},
	journal = {PloS one},
	volume = {11},
	number = {6},
	year = {2016},
	note = {ISBN: 10.1371/journal.pone.0157697 Publisher: Public Library of Science tex.mendeley-tags: 2016,rcc1212,rcc1215,rcc1216,rcc1228,rcc1238,rcc1255,rcc1258,rcc1259,rcc1731,rcc3553},
	month = {jan},
	pages = {e0157697},
	abstract = {Coccolithophores are a vital part of oceanic phytoplankton assemblages that produce organic matter and calcium carbonate (CaCO3) containing traces of other elements (i.e. Sr and Mg). Their associated carbon export from the euphotic zone to the oceans{\textquoteright} interior plays a crucial role in CO2 feedback mechanisms and biogeochemical cycles. The coccolithophore Emiliania huxleyi has been widely studied as a model organism to understand physiological, biogeochemical, and ecological processes in marine sciences. Here, we show the inter-strain variability in physiological and biogeochemical traits in 13 strains of E. huxleyi from various biogeographical provinces obtained from culture collections commonly used in the literature. Our results demonstrate that inter-strain genetic variability has greater potential to induce larger phenotypic differences than the phenotypic plasticity of single strains cultured under a broad range of variable environmental conditions. The range of variation found in physiological parameters and calcite Sr:Ca highlights the need to reconsider phenotypic variability in paleoproxy calibrations and model parameterizations to adequately translate findings from single strain laboratory experiments to the real ocean.},
	keywords = {2016, rcc1212, RCC1215, RCC1216, RCC1228, rcc1238, RCC1255, rcc1258, RCC1259, rcc1731, rcc3553},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0157697},
	url = {http://dx.doi.org/10.1371/journal.pone.0157697},
	author = {Blanco-Ameijeiras, Sonia and Lebrato, Mario and Stoll, Heather M and Iglesias-Rodriguez, Debora and M{\"u}ller, Marius N and M{\'e}ndez-Vicente, Ana and Oschlies, Andreas}
}
