Research undertaken at Australia’s Great Barrier Reef has found that coral reef skeletons are becoming less dense and more fragile.
The study was led by Professor Jonathan Erez from Hebrew University of Jerusalem and Professor Boaz Lazar at Fredy and Nadine Hermann Institute of Earth Scientists, working with Carnegie Institute colleagues Dr J Silverman and Dr K Calderia. The team carried out the study at Lizard Island, where they measured a roughly 40 per cent reduction in the rate of calcium carbonate deposited in Australia’s Great Barrier Reef in the past 35 years.
The researchers compared calcification rates in 2008 and 2009 to those measured using similar techniques in 1975-6. They found that although the coral remained similar, the calcification rates had decreased by between 27 to 49 per cent. The lower rates were consistent with predictions of the increase in CO2 between the two periods, which indicated that ocean acidification is the main cause for the lower calcification rate they found at Lizard Island.
Ocean acidification caused by atmospheric CO2 are a threat to the existence of the delicate reef ecosystems. The success of coral reefs is dependent upon their calcium carbonate structures that function as a filter to enable them to obtain plankton from the water around them. The coral reefs produce almost 50 per cent of annual calcium carbonate in the oceans, playing a crucial role in the global carbon cycle, which increasing ocean acidification could have a major impact on.
Talking on the study, Erez and Silverman say: “The result of this study show a dramatic decrease in the calcification of the reef, and it was likely caused by ocean acidification. When the rate of calcification becomes lower than the rate of dissolution and erosion, the entire coral ecosystem could collapse and eventually be reduced to piles of rubble. The collapse of this habitat would ultimately lead to the loss of its magnificent and highly diverse range of flora and fauna.”
Wildlife Extra, 1 October 2014. Article.
