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Effects of elevated CO 2 on growth, calcification, and spectral dependence of photoinhibition in the coccolithophore Emiliania huxleyi (Prymnesiophyceae) 1
Author(s) -
Lorenzo M. Rosario,
Neale Patrick J.,
Sobrino Cristina,
León Pablo,
Vázquez Víctor,
Bresnan Eileen,
Segovia María
Publication year - 2019
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/jpy.12885
Subject(s) - emiliania huxleyi , coccolithophore , photosynthesis , photoinhibition , biology , photosynthetically active radiation , total inorganic carbon , acclimatization , carbon fibers , environmental chemistry , botany , biophysics , nutrient , carbon dioxide , phytoplankton , photosystem ii , ecology , chemistry , materials science , composite number , composite material
We studied the effects of elevated CO 2 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 chlorophyll a content per cell showed no significant differences between elevated (800 ppmv) and ambient (400 ppmv) CO 2 conditions. However, the production of organic carbon and the cell quotas for both carbon and nitrogen, increased under elevated CO 2 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 CO 2 conditions. The susceptibility of photosynthesis to inhibition by ultraviolet radiation ( UVR ) was estimated using biological weighting functions ( BWF s) and a model that predicts photosynthesis under photosynthetically active radiation and UVR exposures. BWF results demonstrated that the sensitivity of photosynthesis to UVR was not significantly different between E. huxleyi cells grown under elevated and present CO 2 concentrations. We propose that the acclimation to elevated CO 2 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.