Responses of Two Scleractinian Corals to Cobalt Pollution and Ocean Acidification
| Type | Article | ||||||||
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| Date | 2015-04 | ||||||||
| Language | English | ||||||||
| Author(s) | Biscere Tom1, Rodolfo-Metalpa Riccardo1, Lorrain Anne2, Chauvaud Laurent3, Thebault Julien3, Clavier Jacques3, Houlbreque Fanny1 | ||||||||
| Affiliation(s) | 1 : ENTROPIE UMR9220, Inst Rech Dev, Lab Excellence CORAIL, Noumea 98848, New Caledonia. 2 : IRD Noumea, IRD R LEMAR 195, Noumea 98848, New Caledonia. 3 : Univ Brest, Inst Univ Europeen Mer, CNRS IRD UBO UMR6539, Lab Sci Environm Marin, F-29280 Plouzane, France. |
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| Source | Plos One (1932-6203) (Public Library Science), 2015-04 , Vol. 10 , N. 4 , P. e0122898 | ||||||||
| DOI | 10.1371/journal.pone.0122898 | ||||||||
| WOS© Times Cited | 39 | ||||||||
| Note | This is ENTROPIE scientific contribution n. 27. | ||||||||
| Abstract | The effects of ocean acidification alone or in combination with warming on coral metabolism have been extensively investigated, whereas none of these studies consider that most coral reefs near shore are already impacted by other natural anthropogenic inputs such as metal pollution. It is likely that projected ocean acidification levels will aggravate coral reef health. We first investigated how ocean acidification interacts with one near shore locally abundant metal on the physiology of two major reef-building corals: Stylophora pistillata and Acropora muricata. Two pH levels (pH(T) 8.02; pCO(2) 366 mu atm and pH(T) 7.75; pCO(2) 1140 mu atm) and two cobalt concentrations (natural, 0.03 mu g L-1 and polluted, 0.2 mu g L-1) were tested during five weeks in aquaria. We found that, for both species, cobalt input decreased significantly their growth rates by 28% while it stimulated their photosystem II, with higher values of rETR(max) (relative Electron Transport Rate). Elevated pCO(2) levels acted differently on the coral rETR(max) values and did not affect their growth rates. No consistent interaction was found between pCO(2) levels and cobalt concentrations. We also measured in situ the effect of higher cobalt concentrations (1.06 +/- 0.16 mu g L-1) on A. muricata using benthic chamber experiments. At this elevated concentration, cobalt decreased simultaneously coral growth and photosynthetic rates, indicating that the toxic threshold for this pollutant has been reached for both host cells and zooxanthellae. Our results from both aquaria and in situ experiments, suggest that these coral species are not particularly sensitive to high pCO(2) conditions but they are to ecologically relevant cobalt concentrations. Our study reveals that some reefs may be yet subjected to deleterious pollution levels, and even if no interaction between pCO(2) levels and cobalt concentration has been found, it is likely that coral metabolism will be weakened if they are subjected to additional threats such as temperature increase, other heavy metals, and eutrophication. | ||||||||
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