Coral reefs unlikely to spread as oceans warm: Kiwi scientist

New Zealand and Australian scientists have debunked a common belief that ocean warming will lead to coral reef expansion into temperate seas, a New Zealand marine biologist said Friday.

The idea had raised the prospect that some of Australia's famous coral reefs could establish in New Zealand waters as global climate change warmed waters, but this was unlikely, said Dr David Aguirre, of Massey University.

Climate change was expected to see Pacific Ocean temperatures rise over the next 50 years and while some tropical species might be able to expand their range southward, the scientists found that one of three key ingredients coral needed to grow would restrict any expansion, Aguirre said in a statement.

He and colleagues from Australia studied 104 species of one of the most widespread coral varieties, staghorn corals, to determine factors of where corals were likely to grow.

The researchers also found they needed warm temperatures, good light levels and a naturally occurring mineral called aragonite.

Although climate change might make southern areas more favorable for growth in terms of temperature and aragonite, it was unlikely that there would be enough light during the winter months for coral reefs to become established.

The study was the first to look at whether rising ocean temperatures could enable coral spread in Australia and New Zealand.

"Most of the energy these corals need to survive comes from sunlight and light is not predicted to respond to climate change the same way ocean temperature will," said Aguirre. Endi