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Algal evolution in relation to atmospheric CO2: carboxylases, carbon-concentrating mechanisms and carbon oxidation cycles

Raven, John A.; Giordano, Mario; Beardall, John; Maberly, Stephen C.. 2012 Algal evolution in relation to atmospheric CO2: carboxylases, carbon-concentrating mechanisms and carbon oxidation cycles. Philosophical Transactions of the Royal Society (B), 367 (1588). 493-507. 10.1098/rstb.2011.0212

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Abstract/Summary

Oxygenic photosynthesis evolved at least 2.4 Ga; all oxygenic organisms use the ribulose bisphosphate carboxylase-oxygenase (Rubisco)–photosynthetic carbon reduction cycle (PCRC) rather than one of the five other known pathways of autotrophic CO2 assimilation. The high CO2 and (initially) O2-free conditions permitted the use of a Rubisco with a high maximum specific reaction rate. As CO2 decreased and O2 increased, Rubisco oxygenase activity increased and 2-phosphoglycolate was produced, with the evolution of pathways recycling this inhibitory product to sugar phosphates. Changed atmospheric composition also selected for Rubiscos with higher CO2 affinity and CO2/O2 selectivity correlated with decreased CO2-saturated catalytic capacity and/or for CO2-concentrating mechanisms (CCMs). These changes increase the energy, nitrogen, phosphorus, iron, zinc and manganese cost of producing and operating Rubisco–PCRC, while biosphere oxygenation decreased the availability of nitrogen, phosphorus and iron. The majority of algae today have CCMs; the timing of their origins is unclear. If CCMs evolved in a low-CO2 episode followed by one or more lengthy high-CO2 episodes, CCM retention could involve a combination of environmental factors known to favour CCM retention in extant organisms that also occur in a warmer high-CO2 ocean. More investigations, including studies of genetic adaptation, are needed.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1098/rstb.2011.0212
Programmes: CEH Topics & Objectives 2009 onwards > Water > WA Topic 2 - Ecohydrological Processes > WA - 2.3 - Assess the responses of river, lake and wetland ecosystems to ecohydrological drivers
CEH Sections: Parr
ISSN: 0962-8436
Additional Information. Not used in RCUK Gateway to Research.: This document is the author’s final manuscript version of the journal article following the peer review process. Some differences between this and the publisher’s version may remain. You are advised to consult the publisher’s version if you wish to cite from this article. http://rspb.royalsocietypublishing.org
Additional Keywords: inorganic carbon, mixing depth, photosynthetically active radiation, Rubisco, temperature, nutrients, UV radiation
NORA Subject Terms: Marine Sciences
Botany
Biology and Microbiology
Ecology and Environment
Date made live: 11 Jan 2012 16:11
URI: http://nora.nerc.ac.uk/id/eprint/16340

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