The world’s largest study of a single coral species   has found that choosing the right partner could mean the difference between survival and death for certain coral species.

The findings of the international study which included University of Queensland researchers,   has significant implications for understanding thermal bleaching tolerances and coral’s potential for survival in a rapidly warming world.

School of Biological Sciences Postdoctoral research fellow Dr Juan Ortiz said the study highlighted how important it was to consider the holobiont – an entire community of living organisms that make up a healthy coral head - if researchers were to understand past and future responses of coral reefs to a rapidly changing environment.

“Reefs that look exactly the same when you dive on them may have completely different ecological properties as a consequence of the different types of algae that the same corals may host,” Dr Ortiz said.
Dr Emma Kennedy, of Griffith’s Australian Rivers Institute who is the lead author in the study, said it was a “mammoth task” to study more than 600 colonies of an endangered coral that is a keystone species in the Caribbean and fundamental to coral reef building.

It was the biggest study done on a single coral species.

The authors found interesting biogeographic patterns in the species of symbionts they found associated with the coral.

The researchers genetically typed colonies of the endangered boulder star coral species Orbicella annularis as well as all the symbionts that were found living inside its tissues.

“As well as being of high conservation and ecological importance, the coral is unusual as it can pair up with a number of different symbiotic algae species; different symbiont types can confer different properties  suh as growth rates or bleaching tolerances to the coral host,” Dr Kennedy said.

“This means that even genetically identical (twin) corals will behave and respond differently to environmental stress if they happen to partner with different symbionts.”

“These relationships are particularly interesting to scientists, as the coral-symbiont pairing can affect bleaching outcomes for corals - literally choosing a different partner could mean the difference between survival and death when sea temperatures become too warm and start disrupting the coral-symbiont relationship.”

Institutions from around the world, including The University of Queensland, Griffith University and lead Exeter University in the United Kingdom collaborated in the paper ‘Symbiodinium biogeography tracks environmental and geographic patterns rather than host genetics in a key Caribbean reef-builder, Orbicella annularis’, published in the journal Proceedings of the Royal Society B.

University of Queensland co-authors also included Associate Professor Sophie Dove and Professor Peter Mumby of the School of Biological Sciences (Associate Professor Dove is also affiliated with the Global Change Institute) and Professor Ove Hoegh-Guldberg, Director of the Global Change Institute.

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