Elevated CO2 Effects in Emiliania huxleyi | Publicaciones | Coccosphere
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Elevated CO2 Effects in the Coccolithophore Emiliania huxleyi (Prymnesiophyceae)

Coccosphere Environmental Analysis

Elevated CO2 Effects in the Coccolithophore Emiliania huxleyi (Prymnesiophyceae)

Title: Effects of Elevated CO2 on Growth, Calcification and Spectral Dependence of Photoinhibition in the Coccolithophore Emiliania huxleyi (Prymnesiophyceae)

Authors: M. Rosario Lorenzo1; Patrick J. Neale2; Cristina Sobrino3; Pablo León4; Víctor Vázquez1; Eileen Bresnan4 and María Segovia1

Acceptance date: 03.05.2019

Journal: Journal of Phycology

DOI: 10.1111/jpy.12885

Affiliations

1 Department of Ecology, Faculty of Sciences, University of Málaga, Bulevar Louis Pasteur s/n, Málaga 29071, Spain

2 Smithsonian Environmental Research Center, 647 Contees Wharf Rd, Edgewater, MD 21037, USA

3 Department of Ecology and Animal Biology, Faculty of Sciences, University of Vigo, Campus Lagoas-Marcosende. 36310 Vigo, Spain

4 Marine Scotland Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB, U.K

Abstract

We studied the effects of elevated CO2 concentrations on cell growth, calcification and spectral variation in the sensitivity of photosynthesis to inhibition by solar radiation in the globally important coccolithophore Emiliania huxleyi. Growth rates and Chl a content per cell showed no significant differences between elevated (800 ppmv) and ambient (400 ppmv) CO2 conditions. However, the production of organic carbon and the cell quotas for both, carbon and nitrogen, increased under elevated CO2 conditions whilst particulate inorganic carbon production rates decreased under the same conditions. Biometric analyses of cells showed that coccoliths only presented significant differences due to treatments in the central area width. Most importantly, the size of the coccosphere decreased under elevated CO2 conditions. The susceptibility of photosynthesis to inhibition by ultraviolet radiation (UVR) was estimated using biological weighting functions (BWFS) and a model that predicts photosynthesis under photosynthetically active radiation (PAR) and UVR exposures. BWF results demonstrate that the sensitivity of photosynthesis to UVR was not significantly different between E. huxleyi cells grown under elevated and present CO2 concentrations. We propose that the acclimation to elevated CO2 conditions involves a physiological mechanism of regulation and allocation of energy and metabolites in the cell, which is also responsible for altering the sensitivity to UVR. In coccolithophores this mechanism might be affected by the decrease in the calcification rates.

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