Premium
Dissecting the impact of CO 2 and pH on the mechanisms of photosynthesis and calcification in the coccolithophore Emiliania huxleyi
Author(s) -
Bach Lennart T.,
Mackinder Luke C. M.,
Schulz Kai G.,
Wheeler Glen,
Schroeder Declan C.,
Brownlee Colin,
Riebesell Ulf
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12225
Subject(s) - emiliania huxleyi , coccolithophore , ocean acidification , photosynthesis , carbonate , bicarbonate , total inorganic carbon , environmental chemistry , chemistry , phytoplankton , dissolved organic carbon , botany , carbon dioxide , biophysics , ecology , biology , biochemistry , seawater , nutrient , organic chemistry
Summary Coccolithophores are important calcifying phytoplankton predicted to be impacted by changes in ocean carbonate chemistry caused by the absorption of anthropogenic CO 2 . However, it is difficult to disentangle the effects of the simultaneously changing carbonate system parameters ( CO 2 , bicarbonate, carbonate and protons) on the physiological responses to elevated CO 2 . Here, we adopted a multifactorial approach at constant pH or CO 2 whilst varying dissolved inorganic carbon (DIC) to determine physiological and transcriptional responses to individual carbonate system parameters. We show that Emiliania huxleyi is sensitive to low CO 2 (growth and photosynthesis) and low bicarbonate (calcification) as well as low pH beyond a limited tolerance range, but is much less sensitive to elevated CO 2 and bicarbonate. Multiple up‐regulated genes at low DIC bear the hallmarks of a carbon‐concentrating mechanism (CCM) that is responsive to CO 2 and bicarbonate but not to pH . Emiliania huxleyi appears to have evolved mechanisms to respond to limiting rather than elevated CO 2 . Calcification does not function as a CCM , but is inhibited at low DIC to allow the redistribution of DIC from calcification to photosynthesis. The presented data provides a significant step in understanding how E. huxleyi will respond to changing carbonate chemistry at a cellular level.