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

To evaluate the effect of elevated pCO2 exposure on the juvenile growth of the sea urchin Lytechinus variegatus, we reared individuals for 3 months in one of three target pCO2 levels: ambient seawater (380 μatm) and two scenarios that are projected to occur by the middle (560 μatm) and end (800 μatm) of this century. At the end of 89 days, urchins reared at ambient pCO2 weighed 12% more than those reared at 560 μatm and 28% more than those reared at 800 μatm. Skeletons were analyzed using scanning electron microscopy, revealing degradation of spines in urchins reared at elevated pCO2 (800 μatm). Our results indicate that elevated pCO2 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.

► We evaluate the effect of ocean acidification on juvenile urchin growth.
► We show that elevated pCO2 depresses juvenile urchin growth.
► Scanning electron microscopy indicates that elevated pCO2 alters skeletal integrity.