1932

Abstract

The accumulation of inorganic carbon from seawater by eukaryotic marine phytoplankton is limited by the diffusion of carbon dioxide (CO) in water and the dehydration kinetics of bicarbonate to CO and by ribulose-1,5-bisphosphate carboxylase/oxygenase's (RubisCO) low affinity for its inorganic carbon substrate, CO. Nearly all marine phytoplankton have adapted to these limitations and evolved inorganic carbon (or CO) concentrating mechanisms (CCMs) to support photosynthetic carbon fixation at the concentrations of CO present in ocean surface waters (<10–30 μM). The biophysics and biochemistry of CCMs vary within and among the three dominant groups of eukaryotic marine phytoplankton and may involve the activity of external or intracellular carbonic anhydrase, HCO transport, and perhaps a C carbon pump. In general, coccolithophores have low-efficiency CCMs, and diatoms and the haptophyte genus have high-efficiency CCMs. Dinoflagellates appear to possess moderately efficient CCMs, which may be necessitated by the very low CO affinity of their form II RubisCO. The energetic and nutrient costs of CCMs may modulate how variable CO affects primary production, element composition, and species composition of phytoplankton in the ocean.

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/content/journals/10.1146/annurev-marine-120709-142720
2011-01-15
2024-06-17
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  • Article Type: Review Article
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