Elevated CO₂ delays the early development of scleractinian coral Acropora gemmifera

The effects of elevated CO₂ on the early life stages of coral were investigated by culturing the pelagic larvae and new recruits of Acropora gemmifera at three concentrations of CO₂ (corresponding to pH = 8.1, 7.8 and 7.5, respectively). Acidified seawater resulted in fewer A. gemmifera larvae settling, and led to the production of smaller new recruits by slowing the development of the skeleton. The delayed development of new recruits due to elevated CO₂ was consistent with the downregulation of calcification related genes. Several genes related to HCO₃^- and Ca²⁺ transporters were downregulated by elevated CO₂, with solute carriers (SLC) (membrane transport proteins) possibly playing an important role. The downregulation of these membrane transport proteins might suppress the transport of calcium, bicarbonate and organic matter, resulting in the delayed development of A. gemmifera.