Ocean acidification slowly damaging coral reefs

Scientists have found that acidification in ocean can lead to disintegration of the coral reefs.

While coral reefs are the most ecologically diverse and productive ecosystem in the ocean, producing almost 50 percent of the net annual calcium carbonate, hence playing an important role in the global carbon cycle, over 35 years, there has been a 40 percent reduction in calcium carbonate deposits in Australia's Great Barrier Reef.

The discovery was made an expedition from the Hebrew University of Jerusalem and the Carnegie Institute of Science, and the scenario that could damage the reef framework and endanger the entire coral ecosystem.

To better understand the effect of acidification on coral growth decline, the scientists had carried out a community metabolism study in Lizard Island at the Great Barrier Reef in Australia.

The researchers compared calcification rates documented in 2008 and 2009 to those measured using similar techniques in 1975-6. Despite the fact that the coral cover remained similar, the researchers found that the recent calcification rates had decreased by between 27 percent and 49 percent. The lower rates were consistent with predictions that took into account the increase in CO2 between the two periods, suggesting that ocean acidification was the main cause for the lower calcification rate at Lizard Island.

The findings suggested that coral reefs were now making skeletons that were less dense and more fragile. While they still looked the same, these coral reefs were less able to resist physical and biological erosion.

The study is published in Geochimica et Cosmochimica Acta, a journal of the Geochemical Society and the Meteoritical Society.