Scientists successfully develop 'heat resistant' coral to fight bleaching

Scientists successfully develop 'heat resistant' coral to fight bleaching
A healthy coral reef, Hardy Reef in Queensland, Australia. Aerial view. When corals are of good health, they are known for their vibrant colors. Credit: The Commonwealth Scientific and Industrial Research Organization (CSIRO)

The team included researchers from CSIRO, Australia's national science agency, the Australian Institute of Marine Science (AIMS) and the University of Melbourne.

Corals with increased have the potential to reduce the impact of reef bleaching from marine heat waves, which are becoming more common under .

"Coral reefs are in decline worldwide," CSIRO Synthetic Biology Future Science Platform (SynBio FSP) science lead Dr. Patrick Buerger said.

"Climate change has reduced , and surviving corals are under increasing pressure as water temperatures rise and the frequency and severity of coral bleaching events increase."

The team made the coral more tolerant to temperature-induced bleaching by bolstering the heat tolerance of its microalgal symbionts—tiny cells of algae that live inside the coral tissue.

"Our novel approach strengthens the heat resistance of coral by manipulating its microalgae, which is a key factor in the coral's heat tolerance," Dr. Buerger said.

The team isolated the microalgae from coral and cultured them in the specialist symbiont lab at AIMS. Using a technique called "directed evolution", they then exposed the cultured microalgae to increasingly over a period of four years.

Scientists successfully develop 'heat resistant' coral to fight bleaching
Coral bleaching. The white skeleton of the soral is visible because it suffered from extensive heat stress and lost their important algal symbiont, which supplies most of the coral’s nutrition through photosynthesis. Credit: The Commonwealth Scientific and Industrial Research Organization (CSIRO)

This assisted them to adapt and survive hotter conditions.

"Once the microalgae were reintroduced into coral larvae, the newly established coral-algal symbiosis was more heat tolerant compared to the original one," Dr. Buerger said.

The microalgae were exposed to temperatures that are comparable to the ocean temperatures during current summer marine heat waves causing coral bleaching on the Great Barrier Reef.

The researchers then unveiled some of the mechanisms responsible for the enhanced coral bleaching tolerance.

"We found that the heat tolerant microalgae are better at photosynthesis and improve the heat response of the coral animal," Professor Madeleine van Oppen, of AIMS and the University of Melbourne, said

"These exciting findings show that the microalgae and the coral are in direct communication with each other."

Footage of a healthy coral reef with vibrant colors (min 00:03 – 00:10). Bleached corals with white skeletons that suffered from heat stress (00:10 – 00:20). Coral spawning releasing eggs and sperm bundles, wide shot (00:21 – 00:29). Coral spawning releasing eggs and sperm bundles, close up shot (00:29 – 00:38). Coral spawning laboratory work (00:38 – 00:44). Coral spawning in laboratory (00:44 – 00:55). Laboratory work (00:55 – 01:31). Coral larvae settling into a polyp (01:31 – 01:41). Coral poly (01:41 – 01:50). Credit: The Australian Institute of Marine Science (AIMS) and The Commonwealth Scientific and Industrial Research Organization (CSIRO)

The next step is to further test the algal strains in adult colonies across a range of species.

"This breakthrough provides a promising and novel tool to increase the heat tolerance of corals and is a great win for Australian science," SynBio FSP Director Associate Professor Claudia Vickers said.


Explore further

Corals' partnership with microalgae helps in stressful times but there's a trade-off

More information: P. Buerger el al., "Heat-evolved microalgal symbionts increase coral bleaching tolerance," Science Advances (2020). advances.sciencemag.org/content/6/20/eaba2498
Journal information: Science Advances

Provided by CSIRO
Citation: Scientists successfully develop 'heat resistant' coral to fight bleaching (2020, May 13) retrieved 1 December 2020 from https://phys.org/news/2020-05-scientists-successfully-resistant-coral.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
7150 shares

Feedback to editors

User comments