Effects of Ocean Acidification on Metabolism in the Blue Mussel Mytilus edulis

Ocean acidification driven by global climate change is altering the marine carbonate system and posing increasing pressure on marine organisms. The blue mussel Mytilus edulis is an important species in intertidal ecosystems, and ocean acidification may pose a potential threat to it. To understand how ocean acidification affects the physiological metabolism of Mytilus edulis, we set up three acidification scenarios (pH 7.8, 7.6, 7.4) representing projections for the next 300 years and exposed the mussels for 30 days. We looked at four indicators: filtration rate, oxygen consumption rate, ammonia excretion rate, and O:N ratio. The results showed that ocean acidification significantly affected the physiological metabolism of Mytilus edulis. At pH 7.4, compared with the control group (pH 8.1), filtration rate fell by 40.1%, oxygen consumption rate by 29.3%, and O:N ratio by 62.8%, indicating energy imbalance. These findings suggested that ocean acidification suppresses feeding and respiratory metabolism in Mytilus edulis and disrupts its overall metabolic processes. Under future ocean conditions, such metabolic disturbances may further affect energy balance and pose potential threats to ecosystem function and stability.