Climate change is affecting the health and physiology of marine organisms and altering species interactions. Ocean acidification ( OA ) threatens calcifying organisms such as the Pacific oyster, Crassostrea gigas . In contrast, seagrasses, such as the eelgrass Zostera marina , can benefit from the increase in available carbon for photosynthesis found at a lower seawater pH . Seagrasses can remove dissolved inorganic carbon fro...