Coral reefs can take the heat

Jan 30, 2012, 8:55 GMT

Sydney - Good news: there is further evidence that coral reefs can cope with the rising sea temperatures associated with climate change.

Researchers working on the Great Barrier Reef have found that the assembly of 2,900 individual reefs stretching 2,600 kilometres down Australia's east coast can adapt to warmer waters.

Emily Howells, from James Cooke University in Townsville, Queensland, set out to see whether it was right to assume that corals that flourished in warmer waters had different energy-producing algal cells from those that lived in cooler waters. She found that the cells, called zooanthellae, had different rates of adaptability to rising temperature and that this held true across those from cooler waters and those from warmer waters.

'Previously we knew that it was different types of zooanthellae that vary in their temperature tolerations, so if a coral was going to be thermally tolerant through its zooanthellae it would have to be able to host different types,' she said. 'Now, in the research that I did, also within one type of zooanthellae there are different levels of thermal tolerance and that's because different populations have adapted to different thermal environments.'

Her research, published in the journal Nature Climate Change, showed that the adaptability of zooanthellae 'may assist corals to increase their thermal tolerance and persist into the future.'

Over recent years the research on the Great Barrier Reef has shown corals are hardier than scientists previously thought. This is important to Australia: the reef has 2 million visitors a year and underpins tens of thousands of jobs in tourism.

'Overall, it's good news for coral, but we need to keep it in context,' Howells said. 'The overarching question is whether they can adapt at the same rate that the ocean temperature is rising.

'It's better to do research to quantify rates of adaptation than to have a guessing game on whether they can't adapt and they are all going to die or whether they can adapt - and adapt at the rate the ocean temperature is rising.'