Assisted Evolution: A chance to save the reef?

The Australian government’s marine research agency is looking to use ‘assisted evolution’ to help species of coral cope with rising sea temperatures, as new modelling projected that the coverage of living corals on the Great Barrier Reef could decline to less than 10% if warming continues.

The iconic Great Barrier Reef is the world’s largest reef system. Spanning 345,000 square kilometres in size, it runs parallel with the coast of Queensland, Australia and supports a vast diversity of marine life. It is home to more than 1,500 species of fish, 411 types of hard coral, one-third of the world’s soft corals, 134 species of sharks and rays, six of the world’s seven species of threatened marine turtles, and more than 30 species of marine mammals, including the vulnerable dugong1.

However in recent years, climate change, pollution, invasive species introductions and fishing are having devastating impacts on the biodiversity and health of the reef system. According to findings by the National Academy of Sciences, coral cover on the Great Barrier Reef has declined by 50% since 1985, as a result of anthropogenic factors including mortality and reduced growth of corals due to high sensitivity to rising seawater temperatures, ocean acidification, water pollution from terrestrial runoff, destructive fishing, overfishing, and coastal development 2.

A recent study predicted that there is a high likelihood of coral cover declining to 10% globally due to increasing temperature and/or local threats, with corals potentially being replaced by sponges, gorgonians, algal species and other taxa 3. With the failing health of earth’s coral reef systems, scientists at the Australian Institute of Marine Science have partnered with the Hawaii Institute of Marine Biology to look at how “assisted evolution” may help corals more quickly adapt to climate change.

According to Dr Madeleine van Oppen, a lead author on the paper, environmental engineering techniques will be utilised for building coral reef resilience, also including breeding a new generation of corals to be more tolerant of certain conditions and selective breeding.

The project has so far taken place at the Australian institute’s sea simulator in Townsville, Queensland, where different types of coral were picked shortly before their annual spawning and matched via IVF to create new hybrids. Scientists reared the coral larvae and then settled them to assess their growth into juveniles. Through crossing coral from the central part of the Great Barrier Reef with coral from the colder reaches of the southern reef, the team of researchers aim to see if the resulting hybrid is more resilient in higher water temperatures. The scientists are investigating whether they can alter the zooxanthellae communities, the algae that live within coral tissue, so that they can adapt to climate change. It is hoped that the research can speed up the evolutionary process so that corals can cope with the rate of rising sea temperatures.

“I think it is a last resort,” Dr Oppen said. “But you have to develop the biological tool kit now because it will take some time, so we have to test the various options before it is too late.”

– JK

For more information on the project: Australian Institute of Marine Science

References used:

    1. Jennifer K. Cooper, Matthew Spencer, John Francis Bruno. Stochastic dynamics of a warmer Great Barrier Reef. Ecology, 2014; 141120023322006 DOI:10.1890/14-0112.1

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