MEPS 502:145-156 (2014)  -  DOI: https://doi.org/10.3354/meps10720

Positive and negative responses of coral calcification to elevated pCO2: case studies of two coral species and the implications of their responses

Hui Huang1,2, Xiang-Cheng Yuan1,*, Wei-Jun Cai3, Cheng-Long Zhang1, Xiubao Li1, Sheng Liu1

1Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences (CAS), Guangzhou, PR China
2Tropical Marine Biological Research Station in Hainan, CAS, Sanya 572000, PR China
3School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, USA
*Corresponding author:

ABSTRACT: Fragments of 2 coral species (Acropora nasuta and Pocillopora damicornis), collected from the South China Sea, were incubated for 94 d under controlled conditions of pCO2 = 389, 700, and 1214 µatm. Our incubation experiments showed that the net calcification rate of A. nasuta responded negatively to elevated pCO2 in both short and mid-term incubations. In contrast, the net calcification rate of P. damicornis increased under elevated pCO2 during the first 17 d, but then returned to background rates. Based on previous models, our modified models showed that the different responses of these 2 coral species depended on the dissolved inorganic carbon (DIC) and pH levels in coral calcifying fluid. In the studied models, the positive responses of coral calcification to higher pCO2 could be explained by either low DIC due to a higher photosynthesis rate or a stronger H+ pump. If DIC in calcifying fluid is greatly reduced by photosynthesis, the decreased DIC in calcifying fluid may be benefited by enhanced external seawater CO2, which will partially offset the dissolution due to ocean acidification. Therefore, in addition to our experimental results, our model provides a theoretical basis showing how coral may respond negatively and positively to ocean acidification.


KEY WORDS: Coral calcification · Ocean acidification · Dissolved inorganic carbon · pH · Modelling


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Cite this article as: Huang H, Yuan XC, Cai WJ, Zhang CL, Li X, Liu S (2014) Positive and negative responses of coral calcification to elevated pCO2: case studies of two coral species and the implications of their responses. Mar Ecol Prog Ser 502:145-156. https://doi.org/10.3354/meps10720

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