Juvenile growth of the tropical sea urchin Lytechinus variegatus exposed to near-future ocean acidification scenarios

To evaluate the effect of elevated pCO ₂ exposure on the juvenile growth of the sea urchin Lytechinus variegatus, we reared individuals for 3months in one of three target pCO ₂ levels: ambient seawater (380μatm) and two scenarios that are projected to occur by the middle (560μatm) and end (800μatm) of this century. At the end of 89days, urchins reared at ambient pCO ₂ weighed 12% more than those reared at 560μatm and 28% more than those reared at 800μatm. Skeletons were analyzed using scanning electron microscopy, revealing degradation of spines in urchins reared at elevated pCO ₂ (800μatm). Our results indicate that elevated pCO ₂ levels projected to occur this century may adversely affect the development of juvenile sea urchins. Acidification-induced changes to juvenile urchin development would likely impair performance and functioning of juvenile stages with implications for adult populations.