GBR Corals Weakening Rapidly; Calcium Deposition Rates Drop Nearly 50% Over 40 Yrs @ Queensland Site
The skeleton hand of ocean acidification has been found at work near one of Australia's most exotic tropical destinations, Lizard Island on the Great Barrier Reef. Scientists surveying a reef flat just south of the resort island, off Cooktown, have measured a near 40 per cent decline in deposition of the vital building block for healthy coral, calcium carbonate.
The fall, detected by a team from Israel's Hebrew University, underscores the need for rapid action to arrest ocean acidification caused by climate change, Australian marine scientist Ove Hoegh-Guldberg said on Friday.
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A landmark Australian Institute of Marine Science study in 2009 tracked an 11.2 per cent decline over 15 years in calcification of massive porites-type corals throughout the Great Barrier Reef system – unprecedented in at least the past 400 years. At the Lizard Island reef, acidification effects were detected across the whole coral community surveyed. The results were published in a study this week that compared calcification rates in 2008-09 with an original survey in 1975-76.
The Hebrew University researchers found that although the extent of coral cover was about the same as when it was first examined, calcification rates had fallen by between 27 and 49 per cent, leaving the corals less dense and more fragile. These lower rates are consistent with predictions that take into account the increase in carbon dioxide uptake in the ocean over the same 33-year time span.
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http://www.smh.com.au/environment/survey-finds-great-barrier-reef-coral-losing-strength-20141003-10puas.html
