Measurement of DIC acquisition and evidence for a CO₂ concentrating mechanism in Gephyrocapsa oceanica (Isochrysidales, Coccolithophyceae)

ABSTRACT

The possession of a carbon concentrating mechanism (CCM) by a given phytoplankton species will in part determine its response to changes in the dissolved inorganic carbon concentrations in the global ocean. Earlier work on CCMs in the coccolithophore Emiliania huxleyi suggested that this species did not possess a CCM, though more recent studies indicate that a CCM is indeed present. Here we report work showing that another coccolithophore species, Gephyrocapsa oceanica, also possesses a functioning CCM, implying that increasing CO₂ concentrations are unlikely to lead to enhanced growth rates. We discuss the protocol required for working with this species, noting that due to its liths being 10 or more times as massive as of those of Emiliania huxleyi, much lower centrifugation speeds (<400 × g) must be used to avoid damage to the cells.

KEYWORDS:

• CCM
• Cell damage
• Centrifuge speed
• Coccolithophore

ACKNOWLEDGEMENTS

The authors thank an anonymous reviewer and Doug Campbell for helpful comments.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

Additional information

Funding

The first author gratefully acknowledges the award of a Dean’s scholarship at Monash University that made some of this research possible.