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Potential costs of acclimatization to a warmer climate : growth of a reef coral with heat tolerant vs. sensitive symbiont types

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journal contribution
posted on 06.12.2017, 00:00 authored by Alison JonesAlison Jones, R Berkelmans
One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae) genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 orthermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type Dzooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change.

Funding

Category 4 - CRC Research Income

History

Volume

5

Issue

5

Start Page

1

End Page

9

Number of Pages

9

eISSN

1932-6203

Location

USA

Publisher

PloS ONE

Language

en-aus

Peer Reviewed

Yes

Open Access

No

External Author Affiliations

Australian Institute of Marine Science; Centre for Environmental Management; Institute for Resource Industries and Sustainability (IRIS);

Era Eligible

Yes

Journal

PLoS ONE.