Heat-Tolerant Algae Gives Hope For Corals
A new species of heat-tolerant algae gives hope to the future of coral reefs as water temperatures across the world rise
A collaborative study between the University of Southampton and the University of New York Abu Dhabi found that the new algae species (Symbiodinium thermophilum) discovered in the Southern Arabian Gulf helps corals survive in waters as warm as 36 degrees Celsius, temperatures considered to be lethal to corals.
‘It gives hope to find that corals have more ways to adjust to stressful environmental conditions than we had previously thought,’ Jörg Wiedenmann, Professor of Biological Oceanography at the University of Southampton and co-author of the study said.
Speaking to DIVE, Associate Professor of Biology at NYU Abu Dhabi and co-author of the report, John Burt, said, ‘The Arabian Gulf is one of the most thermally extreme seas in the world, so we expected that we would find some interesting coral-associated algae (zooxanthallae) on these reefs’.
Surprisingly, the type of algae found to dominate the Arabian corals as they are part of a group of algae which is not expected to survive in warm temperatures.
‘It had evolved and adapted in the Gulf's unique environment to such an extent that - by several lines of evidence - it had evolved into a new species’, Burt explained.
Most reef-building corals are dependent on the symbiotic relationship with these microscopic algae. In return for nutrients and shelter, photosynthesis allows algae to produce sugars vital for the coral's diet and are responsible for the coral's pigmentation.
However, this symbiotic relationship is extremely delicate to changes in heat. Under heat-stress, a coral might expel its zooxanthallae, the phenomenon known as coral bleaching, which leaves the white coral skeleton to starve.
‘However, it is not only heat that troubles coral reefs,’ he added.
‘Pollution and nutrient enrichment, overfishing and coastal development also represent severe threats to their survival. Only if we manage to reduce these different forms of stress will corals be able to benefit from their capacity to adjust to climate change.’
The study was published in Nature in January 2015