Calcification and photobiology in symbiont-bearing benthic foraminifera and responses to a high CO2 environment

► The response to pCO2 increase was investigated on three benthic foraminifera. ► M. vertebralis shows increased calcification after 41 days in elevated CO2 dosing. ► Increased pCO2 showed no effect on photobiology of the foraminifera investigated. ► Previous field studies indicate long-term impacts of high CO2 conditions. ► The study highlights that laboratory experiments can differ from field observation.