Microbes implicated in coral reefs’ death

Climate change is often cited as the cause of the death of some of the world’s coral reefs but a new study says other factors are equally to blame.

Biologists at Newcastle University say the reefs could be dying out because of changes to the microbes that live in them just as much as from rising temperatures caused by global warming.

The microbes are described as being similar to the bacteria that live in people’s stomachs and help to digest food.

When the sea temperatures rise some disease-causing bacteria become more successful and attack coral at the same time that some of the friendly bacteria suffer from heat and become weakened.

This allows harmful bacteria to multiply and cause disease of other problems.

“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 per cent of the world’s reefs were killed, can be put down to changes in the microbes which live in and around the reefs,” said Dr John Bythell.

“We need a better understanding of the processes and mechanisms that impact on corals and the reefs when sea temperatures rise to confirm the ultimate causes of their decline.”

He added: “Although local actions to reverse the overall decline in reef health are probably not feasible, we need this better understanding to try to reduce or eliminate contributing causes.

“Some of the changes in the microbes’ environment could be locally managed, for example by reducing general pollution, cutting soil erosion into the sea which chokes the reefs, and avoiding harmful run-off from farming practices.”

Coral reefs cover 0.2 per cent of the ocean floor and are home to 25 per cent of marine species globally.

They also provide livelihoods to 100 million people and the basis for industries such as tourism and fishing, which are worth an annual net benefit of $US 30 billion (