Great Barrier Reef Suffers 2nd Year of Mass Bleaching

Scientists in Australia have revealed unprecedented damage to the Great Barrier Reef, warning "we are entering uncharted territory".

Surveys have shown the coral reef is entering its second consecutive year of bleaching for the first time, Themarshalltown.com reported. Bleaching happens when algae living in the coral are expelled due to stress caused by extreme changes in temperatures, turning the coral white and putting it at risk of dying.

The first aerial survey of 2017 has found shocking levels of bleaching in the central part of the reef, the Great Barrier Reef Marine Park Authority said.

Marine Park Authority's director for reef recovery, David Wachenfeld, said, "Mass bleaching is occurring on the Great Barrier Reef for the second consecutive year. How this event unfolds will depend very much on local weather conditions over the next few weeks."

He said not all bleached coral would die, and last year showed that bleaching and mortality could be highly variable across the vast marine park, a World Heritage Site covering an area larger than Italy. The Great Barrier Reef is the world’s largest collection of coral reefs, with 400 types of coral, 1,500 species of fish and 4,000 mollusc species, and is the habitat of wildlife such as the dugong—sea cow—and the large green turtle.

Conditions on the reef are part of a global coral bleaching event over the past two years, as a result of unusually warm ocean temperatures due to climate change and a strong El Nino weather phenomenon that pushes temperatures up further.

Neal Cantin, from the Australian Institute of Marine Science, said the recurrence of widespread coral bleaching in back-to-back summers indicated there was not enough time since 2016’s extreme heat event for the corals to fully recover.

"We are seeing a decrease in the stress tolerance of these corals," he said. "This is the first time the Great Barrier Reef has not had a few years between bleaching events to recover … We are now entering uncharted territory."

John Tanzer, from World Wildlife Fund International, said, "What is unfolding before our very eyes is the starkest evidence that climate change is already wreaking havoc on the ocean.

"Coral reefs are a beloved natural wonder but less appreciated is that they also directly support the jobs, livelihoods and food supplies of many millions of people. What will happen to these people as large areas of coral die?"