How do corals build their "bones"?

Climate change is a big problem for corals, which provide homes for about 25 per cent of marine life.
Ocean acidification, caused by the oceans absorbing carbon dioxide from the atmosphere, has a particularly severe impact on stone corals, making it harder for these animals to precipitate bones made up of calcium carbonate, the same molecule found in antacids for heartburn and indigestion.
now, scientists say corals have some active control over the growth of their bones to protect them from the worst damage from ocean acidification.
to understand how corals build their "bones," scientists used ultra-high-resolution microscopic imaging to observe the contours of common stone corals, sliver-shaped column corals.
images show that corals are able to secrete a template of acidic proteins that form calcium carbonate, which is formed by calcium and carbon ions in surrounding water, to form mineral crystals that form the core of coral "bones."
this provides the strongest evidence to support biologically controlled coral bone growth, the team reported in a June 1 article in Science.
because the acid protein works more widely than expected, scientists say, corals can continue to form coral reefs even when the oceans are acidified.
does not mean that coral reefs will grow unhindered.
first, they still need the calcium carbonate building blocks that make up their biological home, which is less in the more acidic oceans.
, they are still under great threat from warm waters and algae blooms that can lead to coral bleaching and death.
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