The Great Barrier Reef has "died" at least five times in the last 30,000 years, as it has, according to a recent study of sudden environmental changes Had to keep up.
Two widespread deaths from 30,000 to 22,000 years ago according to the study. Both were subaerial exposures, meaning that the reef was exposed to the air. During this time, the reef shifted towards the sea, to keep up with the falling sea levels.
The last glacial maximum saw two more reef deaths 17,000 to 13,000 years ago due to a sudden rise in sea level, causing the reef to move towards the land to keep up. The last death event, which occurred about 10,000 years ago, appears to have been triggered by massive sea sediment accumulation around the reef and the resulting poor water quality, in addition to the general sea level rise.
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"Our study shows that the reef was able to recover from past deaths during the last Ice Age and de-icing Jump back, "said lead author and associate professor of Sydney University School of Earth Sciences Jody Webster in the publication. "However, we found it also very sensitive to increased sediment input, which is important given current land-use practices."
The researchers used data from fossil reef cores collected at 16 sites around Mackay and Cairns time frame just before the "last glacier maximum" about 20,000 years ago. At that time, sea levels were more than 380 feet lower than today.
The reef, due to the habits of its corals and coralline algae and corals, has probably adapted over time to the ecosystem's ability to move sideways between about 2 and 5 feet annually.
Despite the ecosystem's ability to migrate, Webster believes that the speed at which it moves is likely to be insufficient to weather the current sea surface temperature rise rates, steep drops in coral cover, and repeated coral bleaching. and an increase in sediment.
"I have great concerns about the ability of the reef in its present form to withstand the pace of change caused by the many current and projected tensions in the near future," Webster said.
"Our study shows that in addition to responding to sea level changes, reef has been particularly sensitive to sediment flows in the past, which means that in the current period we must understand how primary industry practices affect sediment input and water quality Reef influence, "he added.
"If you can conserve and minimize some of the damage you can continue to restore it over a long period of time," says ARC's Center of Excellence. The Research Team of Coral Reef Studies, Tom Bridge , who was not involved in the study, told the Sydney Morning Herald: "We need to make sure the conditions [for the reef] are in place to recover."