Natural in situ relationships suggest coral reef calcium carbonate production will decline with ocean acidification. (11th February 2015)

• Record Type: Journal Article
• Authors: Shaw, Emily C.; Phinn, Stuart R.; Tilbrook, Bronte; Steven, Andy
• Is Part Of: Limnology and oceanography. Volume 60:Number 3(2015:May)
• Page Start: 777
• Page End: 788
• Publication Date: 2015-02-11
• Subjects: Limnology -- Periodicals; Oceanography -- Periodicals; Océanographie; Limnologie; Limnology; Oceanography; Computer network resources; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); Periodicals; 551.4805
• DOI: 10.1002/lno.10048
• Languages: English
• ISSNs: 0024-3590

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>There are few in situ studies showing how net community calcification (<italic>G</italic><sub>net</sub>) 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 (<italic>P</italic><sub>net</sub>), <italic>G</italic><sub>net</sub>, and carbonate chemistry of a reef flat at One Tree Island, Great Barrier Reef. Diurnal <italic>p</italic>CO<sub>2</sub> 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<sup>−2</sup> d<sup>−1</sup> and net calcification of ∼ 33 mmol C m<sup>−2</sup> d<sup>−1</sup>. <italic>G</italic><sub>net</sub> was strongly related to <italic>P</italic><sub>net</sub>, which drove a hysteresis pattern in the relationship between <italic>G</italic><sub>net</sub> and aragonite saturation state (Ω<sub>ar</sub>). Although <italic>P</italic><sub>net</sub> was the main driver of <italic>G</italic><sub>net</sub>, Ω<sub>ar</sub> was still an important factor, where 95% of the variance in <italic>G</italic><sub>net</sub> could be described by <italic>P</italic><sub>net</sub> and Ω<sub>ar</sub>. Based on the observed in situ relationship, <italic>G</italic><sub>net</sub> would be expected to reach zero when Ω<sub>ar</sub> is ∼ 2.5. It is unknown what proportion of a decline in <italic>G</italic><sub>net</sub> 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.</p> </abstract>