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Dissecting the impact of CO2 and pH on the mechanisms of photosynthesis and calcification in the coccolithophore Emiliania huxleyi


Bach, LT and Mackinder, LCM and Schulz, KG and Wheeler, G and Schroeder, DC and Brownlee, C and Riebesell, U, Dissecting the impact of CO2 and pH on the mechanisms of photosynthesis and calcification in the coccolithophore Emiliania huxleyi, New Phytologist, 199, (1) pp. 121-134. ISSN 0028-646X (2013) [Refereed Article]

Copyright Statement

Copyright 2013 the authors New Phytologist Copyright 2013 New Phytologist Trust

DOI: doi:10.1111/nph.12225


  • Coccolithophores are important calcifying phytoplankton predicted to be impacted by changes in ocean carbonate chemistry caused by the absorption of anthropogenic CO2. However, it is difficult to disentangle the effects of the simultaneously changing carbonate system parameters (CO2, bicarbonate, carbonate and protons) on the physiological responses to elevated CO2.
  • Here, we adopted a multifactorial approach at constant pH or CO2 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 CO2 (growth and photosynthesis) and low bicarbonate (calcification) as well as low pH beyond a limited tolerance range, but is much less sensitive to elevated CO2 and bicarbonate. Multiple up‐regulated genes at low DIC bear the hallmarks of a carbon‐concentrating mechanism (CCM) that is responsive to CO2 and bicarbonate but not to pH.
  • Emiliania huxleyi appears to have evolved mechanisms to respond to limiting rather than elevated CO2. 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.

Item Details

Item Type:Refereed Article
Keywords:phytoplankton, ocean acidification, coccolithophore, carbon concentrating mechanism, molecular biology
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Biological oceanography
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Bach, LT (Dr Lennart Bach)
ID Code:134495
Year Published:2013
Web of Science® Times Cited:132
Deposited By:Ecology and Biodiversity
Deposited On:2019-08-15
Last Modified:2019-09-16

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