Combined ocean acidification and low temperature stressors cause coral mortality

Oceans are predicted to become more acidic and experience more temperature variability-both hot and cold-as climate changes. Ocean acidification negatively impacts reef-building corals, especially when interacting with other stressors such as elevated temperature. However, the effects of combined acidification and low temperature stress have yet to be assessed. Here, we exposed nubbins of the scleractinian coral Montipora digitata to ecologically relevant acidic, cold, or combined stress for 2 weeks. Coral nubbins exhibited 100% survival in isolated acidic and cold treatments, but 30% mortality under combined conditions. These results provide further evidence that coupled stressors have an interactive effect on coral physiology, and reveal that corals in colder environments are also susceptible to the deleterious impacts of coupled ocean acidification and thermal stress.

随着气候变化，海洋酸化程度将不断加剧，同时温度波动（涵盖极端高温与极端低温）也将更为频繁。海洋酸化会对造礁珊瑚造成负面影响，尤其当它与温度升高等其他环境胁迫因子联合作用时。但目前学界尚未评估海洋酸化与低温胁迫的联合作用效应。本研究将石珊瑚目指状微孔珊瑚（Montipora digitata）的断枝置于符合生态实际的酸化、低温或联合胁迫环境中，培养时长为2周。单独酸化或单独低温胁迫处理组的珊瑚断枝存活率均为100%，而联合胁迫组的珊瑚断枝死亡率则达到30%。本研究结果进一步证实，多重胁迫因子对珊瑚生理存在交互影响，并揭示寒冷环境中的珊瑚同样易受海洋酸化与热胁迫联合作用的有害影响。