A slowing in the growth of an important reef-building coral in the Great Barrier Reef may point to a disastrous phenomenon that will one day affect all sea creatures, a new report says.
The Australian Institute of Marine Science (AIMS) study examined two regions at the northern end of the reef and found a 21 per cent decline in the rate at which Porites corals, also known as finger corals, had grown in the past 16 years.
“A decline in coral calcification of this magnitude with increasing seawater temperatures is unprecedented in recent centuries,” said the report, published in the Global Change Biology journal.
It suggested the results may be an early sign that the corals, as well as being subjected to warmer water, are being affected by ocean acidification – where climate change caused large quantities of carbon dioxide from the atmosphere to dissolve into the ocean, causing it to become more acidic.
Co-author Janice Lough said more research was needed on exactly what was happening.
“The fact that the two sites are reasonably well separated and have different general characteristics and different average water temperatures but are still showing the same decline in calcification is good evidence that something unusual is happening,” Dr Lough said.
She said their predictions of a pH decrease by up to 0.4 by the end of the century would be “well outside the realms of anything organisms have experienced over hundreds of thousands of years”, affecting all sea creatures.
The Age, 5 March 2008. Article.
