Great Barrier Reef bleaching tipped to worsen as water warms

Coral bleaching across the Great Barrier Reef is expected to increase as warm waters continue to apply stress to parts of the world’s largest living structure.

Coral bleaching across the Great Barrier Reef is expected to increase as warm waters continue to apply stress to parts of the world’s largest living structure.

Reports of “uncomfortably warm” waters off Townsville sparked concerns from marine biologists after corals started bleaching around Magnetic Island in February.

James Cook University PhD student and Magnetic Island resident Blanche D’Anastasi noted the bleaching had intensified around parts of the island since then.

“It still feels like bathwater out there,” she said.

Ms D’Anastasi said some corals had started fluorescing to act as a sun shield.

Great Barrier Reef Park Authority chief scientist David Wachenfeld said cloud cover over the reef had cleared, providing satellites a clearer image of what is happening below the Coral Sea.

“Unfortunately that information is quite concerning. We can see most of the park is at between a half and 1.5 degree above average for March,” he said.

Dr Wachenfeld said temperatures to the south of the park were up to 3C warmer than the March average, and had experienced some of the worst bleaching.

“(With) the forecasts from the Bureau of Meteorology and NOAA (National Oceanic and Atmospheric Administration) we can expect ongoing levels of thermal stress for at least the next two weeks and maybe three or four weeks; that will determine the final outcome,” he said.

The warm ocean temperatures, mixing with humid air could lead to a tropical cyclone forming later this week.

While there is a very low chance of a cyclone forming early this week, the weather bureau said the monsoon trough was expected to strengthen with a tropical low potentially forming in the Gulf of Carpentaria or Coral Sea by midweek.

This year’s bleaching event sparked concern for Magnetic Island resident and retired marine biologist Leon Zann, who filmed corals believed to be decades old bleach white last month.

Dr Zann told the Townsville Bulletin it was the worst bleaching episode he had seen off the island in 50 years.

Originally published as Great Barrier Reef bleaching tipped to worsen as water warms