Ocean Acidification

The coccolithophore Calcidiscus leptoporus (strain RCC1135) was grown in dilute batch culture at CO₂ levels ranging from ∼200 to ∼1600 μatm. Increasing CO₂ concentration led to an increased percentage of malformed coccoliths and eventually (at ∼1500 μatm CO₂) to aggregation of cells. Carbonate chemistry of natural seawater was manipulated in three ways: first, addition of acid; second, addition of a HCO₃⁻/CO₃²⁻ solution; and third, addition of both acid and HCO₃⁻/CO₃²⁻ solution. The data set allowed the disentangling of putative effects of the different parameters of the carbonate system. It is concluded that CO₂ is the parameter of the carbonate system which causes both aberrant coccolithogenesis and aggregation of cells.

Langer G. & Bode M., 2011. CO2 mediation of adverse effects of seawater acidification in Calcidiscus leptoporus. Geochemistry Geophyssics Geosystems 12:Q05001. Article (subscription required).