Great Barrier Reef growing at slowest rate for 400 years

They are the rainforests of the sea, providing food and shelter for millions of marine creatures.

But now tropical coral reefs are facing a renewed – and hidden – threat from environmental change which is stunting their growth, claim scientists.

Researchers looking at the world’s biggest and best preserved reef – the Great Barrier Reef – found that it is growing at its slowest rate for at least 400 years.

While the damage is not visible to the naked eye scientists believe it is a “very worrying” indicator which could spell disaster for the biodiversity of the seas.

Corals, which absorb calcium from the sea to make their hard stone like structure, grow in yearly cycles and using x-rays scientists can measure the annual growth rings.

They have discovered that while growth between 1900 and 1970 increased, it has subsequently started to decline at a rapid rate.

Professor Glenn De’ath, who carried out the research at the Australian Institute of Marine Science, believes that the increased acidification of the sea due to the absorption of carbon dioxide from the atmosphere is the main culprit.

With CO2 levels expected to double in the next 50 years, he believes the changes in the biodiversity are “imminent”

The team, which published the findings in the journal Science, looked at a total of 328 colonies spanning the 1,600 mile long reef which is off the north east coast of Australia.

They found that calcification rates increased 5.4 per cent between 1900 and 1970, but have dropped 14.2 per cent from 1990 to 2005, mainly due to a slowdown in growth from 1.43 centimetres per year to 1.24 centimetres per year.

Clive Wilkinson, global coordinator of the Global Coral Reef Monitoring Network, said decline is “here and now and over the past decade, not some time in the future, as we predicted.”

“This has been happening under our noses,” he added.

Richard Alleyne,, 1st January 2009. Article.

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