Not just global warming, microbes also killing coral reefs

Washington, Apr 6 (UNI) Its not only the rise in temperature due to global warming that are killing the coral reefs but also the microbes that live in them, claims scientists.

''The deaths of the reefs may be as a result of changes in the microbes which live in and around the reefs,'' a biologist from Newcastle University Dr John Bythell said, Science Daily reported.

''These microbes can be thought of as being similar to the bacteria that normally live in our guts and help us digest our food,'' said a researcher.

Changes in sea temperature caused by climate change and global warming affect corals, but they also affect the types of bacteria and other microflora that live with them.

When the water warms up, some disease-causing bacteria are more successful and can attack the corals. The corals themselves suffer from heat, which reduces their defences.

Also, some of the friendly bacteria that normally live in the corals' guts become weakened, allowing other harmful bacteria to multiply and cause diseases or other problems.

Corals in coral reefs, which are made up of animals called polyps that secrete hard external skeletons of calcium carbonate, are living perilously close to their upper temperature limits.

This makes them very vulnerable to even small temperature rises of 1-2 degree Celsius above the normal summer maximum.

''Many of the deaths we see in the coral reefs, which occur following coral bleaching events, when huge areas of reef die off like in 1998 when 17% of the world's reefs were killed,'' said a researcher.

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