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Natural in situ relationships suggest coral reef calcium carbonate production will decline with ocean acidification
Author(s) -
Shaw Emily C.,
Phinn Stuart R.,
Tilbrook Bronte,
Steven Andy
Publication year - 2015
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10048
Subject(s) - reef , ocean acidification , aragonite , carbonate , coral reef , environmental science , calcium carbonate , oceanography , coral , chemistry , climate change , geology , organic chemistry
Abstract There are few in situ studies showing how net community calcification ( G net ) of coral reefs is related to carbonate chemistry, and the studies to date have demonstrated different predicted rates of change. In this study, we measured net community production ( P net ), G net , and carbonate chemistry of a reef flat at One Tree Island, Great Barrier Reef. Diurnal p CO 2 variability of 289–724 μatm was driven primarily by photosynthesis and respiration. The reef flat was found to be net autotrophic, with daily production of ∼ 35 mmol C m −2 d −1 and net calcification of ∼ 33 mmol C m −2 d −1 . G net was strongly related to P net , which drove a hysteresis pattern in the relationship between G net and aragonite saturation state (Ω ar ). Although P net was the main driver of G net , Ω ar was still an important factor, where 95% of the variance in G net could be described by P net and Ω ar . Based on the observed in situ relationship, G net would be expected to reach zero when Ω ar is ∼ 2.5. It is unknown what proportion of a decline in G net would be through reduced calcification and what would occur through increased dissolution, but the results here support predictions that overall calcium carbonate production will decline in coral reefs as a result of ocean acidification.