Is Ocean Acidification Melting Sea Stars? The Effect of Lowered pH and Wasting Disease on Nearshore Asteroid Health
April 12, 2016
Department or Program
Sea Star Wasting Disease (SSWD), the largest wildlife epizootic ever recorded, has killed millions of sea stars since June 2013. Evidence points to a viral infectious agent, Sea Star-Associated Densovirus, and multiple environmental factors are probably involved. This study evaluated the effect of ocean acidification (OA) on the progression of SSWD in four native Puget Sound species. Thirty-five individuals were maintained in ambient pH of Elliot Bay (pH = 7.80 to 8.00) or lowered pH predicted for 2100 (pH = 7.40 to 7.60). Daily visual grading and computed tomography (CT) were used to quantify the effects of OA on sea star health and ossicle density. Our results show that OA conditions accelerate SSWD in mottled sea stars during the first 25 days of exposure. Preliminary analysis indicates that OA decreases ossicle density, suggesting a trade-off between skeletal maintenance and immune function serves to amplify SSWD in OA conditions.