Ocean acidification affects productivity but not the severity of thermal bleaching in some tropical corals

• DOI: 10.1093/icesjms/fsv127
• Publication Date: 2015-07-23T02:10:02Z
• Authors: Sam H. C. Noonan; Katharina E. Fabr...
• Keywords: Coral bleaching; Ocean Acidification

Abstract Increasing carbon dioxide (CO2) emissions are raising sea surface temperature (SST) and causing ocean acidification (OA). While higher SST increases the frequency of mass coral bleaching events, it is unclear how OA will interact to affect this process. In study, we combine in situ surveys around three tropical CO2 seeps with a 2-month two-factor (CO2 temperature) tank experiment investigate combination susceptibility reef corals. Surveys at seep control sites during minor regional event gave little indication that elevated pCO2 influenced wider community, four most common families (Acroporidae, Faviidae, Pocilloporidae, or Poritidae), thermally sensitive species Seriatopora hystrix. experiment, sublethal was observed 31°C after 5 d S. hystrix 12 Acropora millepora, whereas controls (28°C) did not bleach. None measured proxies for negatively affected by pHT 7.79 (vs. 7.95 controls), equivalent ∼780 µatm an aragonite saturation state 2.5. On contrary, high benefitted some photophysiological measures (although effects were much stronger than effects): maximum photosystem II quantum yields light-limited electron transport rates increased both pCO2, gross photosynthesis pigment concentrations pCO2. The field laboratory data suggest levels up 7.8 have effect on sensitivity corals thermal bleaching. Indeed, appear be able utilize more abundant dissolved inorganic increase productivity; however, these gains offset only small proportion massive bleaching-related energy losses stress.