Sea urchin Arbacia dufresnei (Blainville 1825) larvae response to ocean acidification

Increased atmospheric CO 2 emissions are inducing changes in seawater carbon chemistry, lowering its pH, decreasing carbonate ion availability and reducing calcium carbonate saturation state. This phenomenon, known as ocean acidification, is happening at a faster rate in cold regions, i.e. polar and sub-polar waters. The larval development of Arbacia dufresnei from a sub-Antarctic population was studied at high (8.0), medium (7.7) and low (7.4) pH waters. The results show that the offspring from sub-Antarctic populations of A. dufresnei are susceptible to a development delay at low pH, with no significant increase in abnormal forms. Larvae were isometric between pH treatments. Even at calcium carbonate (CaCO 3) saturation states (of both calcite and aragonite, used as proxies of the magnesium calcite)