Coral Scientists Working On Test To Measure Stress Levels In Corals

ARC Centre of Excellence for Coral Reef Studies researchers have identified hemoglobin genes in Zooanthellae that respond to changes in temperature.

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Australian scientists are working on a test to guage stress levels in the symbiotic algae that live with corals. Photo credit: iStockphoto.
John Virata

Australian researchers with the ARC Centre of Excellence for Coral Reef Studies (CoECRS) are working on a stress test for corals that will enable them to measure how corals respond to climate change. The scientists have been able to identify hemoglobin genes in the microalgae that live with the coral which may enable the scientists to determine how stressed a certain coral is, and what its chances are it will bleach and die. These genes respond quickly and dramatically to changes in temperature as well as nutrient stresses, lead author Dr. Nela Rosic of the University of Queensland said.

“When the coral undergo temperature stress, this system goes into overdrive and hemoglobin genes are expressed at a higher level. Due to its sensitive nature, hemoglobin has a potential to be used as a stress biomarker. This, for the first time, gives us a clear readout of stress levels in the corals and their symbiotic algae,” Dr. Rosic said in a press statement released by CoECRS. The scientists say that the primary cause of stress in corals is due to high ocean temperatures caused by global warming.

Professor Hoegh-Guldberg, one of the co-authors of a paper detailing these findings, says the discovery of these hemoglobins will enable scientists to learn more about the physiology of coral bleaching at the molecular level.
“Potentially this can also be used by coral managers and even industries which depend on coral, to monitor the condition of their reefs,” he said. “By monitoring stress levels in the coral’s symbiotic relationship, we can potentially explore whether a coral is more vulnerable to bleaching and death. There may then be strategies we can pursue to reduce the pressure.”

For more information on coral reef bleaching and climate change, click here.

Read about how a disease is killing corals in Kaneohe Bay, Hawaii here.

The paper detailing their findings, “New-old hemoglobin-like proteins of symbiotic dinoflagellates” is published in the journal Ecology and Evolution. The authors are Nedeljka N. Rosic, William Leggat, Paulina Kaniewska, Sophie Dove and Ove Hoegh-Guldberg.

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