Media release

From: The Royal Society

Pacific oysters do not compensate growth retardation following extreme acidification events

Although the effects of ocean acidification on calcifiers are well studied, their recovery capacity has never been evaluated. This is of paramount importance as most calcifiers live in coastal environments with fluctuating pH regimes. We evaluated the recovery capacity of the Pacific oyster exposed to 15 pH levels (6.4 to 7.8) for 14 days and then placed in ambient pH conditions for 42 days. Growth retardation occurred and persisted at pH levels below 7.1, even after the stress was removed. However, growth resumed rapidly suggesting that oysters can recover from extreme acidification but growth retardation cannot be compensated.

• Gimme Shellter – Fluctuating ocean acidification can have lasting impacts on Pacific oyster growth. After 14 days in more acidic conditions oysters were returned to ambient seawater (pH >7.8) – mimicking periods of fluctuating acidity in coastal environments. Oysters did not compensate for the period of inhibited growth, even after the stress was removed, suggesting low resilience to severe acidification episodes. These impacts could have direct economic consequences for shellfish farmers in future, the authors said. Biology Letters