Antinuclear

Complete ecosystem collapse in sections of Great Barrier Reef

Sections of Great Barrier Reef suffering from ‘complete ecosystem collapse’
Coral Watch investigator reports ‘shocking’ lack of fish and says the surviving corals are continuing to bleach, even during winter, Guardian, Michael Slezak, 22 July 16, “Complete ecosystem collapse” is being seen on parts of the Great Barrier Reef, as fish numbers tumble and surviving corals continue to bleach into winter, according to a scientist returning from one of the worst-hit areas.

“The lack of fish was the most shocking thing,” said Justin Marshall, of the University of Queensland and the chief investigator of citizen science program Coral Watch. “In broad terms, I was seeing a lot less than 50% of what was there [before the bleaching]. Some species I wasn’t seeing at all.”

Marshall spent a week this month conducting surveys on the reefs around Lizard Island………overall, Marshall estimate that more than 90% of the branching corals had died around Lizard Island. He said many of the huge porites corals, which could be a thousand years old, had died.

Coral and other organisms like anemones and giant clams bleach when water temperatures are too high for too long. When they become stressed, they expel their colourful symbiotic algae that provide them with energy, becoming pale or white. Unless the water temperatures quickly return to normal, many of those organisms die.

Lizard Island was particularly badly hit by the global bleaching event that hit every major reef region in the world and killed almost a quarter of the coral on the Great Barrier Reef. But, in the northern section of the Great Barrier Reef, between Lizard Island and the Torres Strait, a majority of the coral is thought to have died.

The mass bleaching this year was driven by climate change, which raised water temperatures close to the maximum threshold coral could stand, and a strong El Niño that bumped the temperatures above that threshold. https://www.theguardian.com/environment/2016/jul/21/sections-of-great-barrier-reef-suffering-from-complete-ecosystem-collapse

July 23, 2016 - Posted by Christina Macpherson | climate change - global warming, Queensland