Coccolithophores are microscopic algae that form the base of marine food chains. They secrete calcite shells which eventually sink to the seafloor and form sediments, drawing down and locking away CO2 in rocks. Their calcitic shells have made them more sensitive to ocean acidification, which occurs when increasing amounts of atmospheric CO2 are absorbed by the ocean, which in turn increases seawater acidity.
The study, detailed in PLoS ONE, suggested the findings demonstrated that not all coccolithophore species respond to ocean acidification in the same way. The Emiliania huxleyi species of coccolithophore gets bigger and possesses more calcite under worst-case scenario CO2 levels for the year 2100, and these do not dissolve under high CO2 and elevated acidity.
The strain of Emiliania huxleyi possesses some resilience to tolerate future CO2 scenarios, even though the detected decline in growth rate may be a factor affecting the success of this ecotype in future oceans.