Great Barrier Reef Has Died Five Times In Last 30,000 Years, Study Says (newsweek.com)

schwit1 quotes a report from Newsweek: You may well have heard that Australia's iconic Great Barrier Reef is dying as warmer and more acidic waters bleach the system's vibrant coral reefs. In fact, a heat wave killed nearly a third of the system's corals in 2016. Now, scientists writing in the journal Nature Geoscience have discovered the reef has bounced back from near-extinction five times in the last 30,000 years. The current stresses, however, are probably far more intense than those felt in the past.

Low sea levels 30,000 and 22,000 years ago killed coral by air exposure. The remaining reef shifted seaward and eventually bounced back. Rising sea levels -- like those we see today -- killed off the coral twice between 13,000 and 17,000 years ago. This time, coral inched close to land to survive. The reef system, the scientists think, migrated up to 60 inches a year in the face of a changing environment. The last of the five great die-offs occurred about 10,000 years ago, and was likely caused by a huge influx of sediment, a reduction in water quality and a general sea level rise. The reef system may be due for another die-off sometime in the next few thousand years "if it follows its past geological pattern," study author Jody Webster told AFP. "But whether human-induced climate change will hasten that death remains to be seen."

Comments

Wait a second.. Nature isn't in a vacuum? NO WAY

[SensitiveMale]

All of these chicken littles view these changes in nature as if they are happening in a vacuum.

Nature is like a beanbag. Push here and it pops out there. One change spawns another change. Nothing is static and nature isn't in a vacuum.

Corals have been around

[Kernel Kurtz]

for half a billion years.

They have had worse.

Re:Corals have been around

[Anonymous Coward]

They have had worse.

Of course, and they will bounce back, even if it takes 5000 years, but that isn't the point. A large proportion of fisheries depend on coral reefs, so losing those species rich environments for a long time will hit humanity hard enough that we can feel it. Add to that the other consequences of climate change to food production, migration and so on, and things look not at all rosy. You may prefer to bury your head and pretend everything is going to be fine, but I bet you and those like you will howl the loudest when you find you have to live with the reality of it. And I hope people will point out to you, in no uncertain terms, that you own a big chunk of the responsibility for it.

It always bounces back

[OrangeTide]

Except when it doesn't.

Re:Wait a second.. Nature isn't in a vacuum? NO WA

[quantaman]

All of these chicken littles view these changes in nature as if they are happening in a vacuum.

Nature is like a beanbag. Push here and it pops out there. One change spawns another change. Nothing is static and nature isn't in a vacuum.

Tell that to the Mammoths, Dinosaurs, and the obligate anaerobes that predated cyanobacteria.

Just because a system is resilient doesn't mean you can do whatever the hell you want to it and come out fine.

Re:Fear mongering

[serviscope_minor]

This is all fear mongering. There are reefs in the world with water FAR hotter than the great barrier reef. Despite what researchers who benefit from government funding would like you to believe, there is far from agreement that the reef is in any way in trouble.

If that's fearmongering then your post is stupidmongering.

Yes there are warmer reefs elsewhere. That doesn't mean you can magically transform the great barrier reef into a hot water reef without it first crashing badly and for a long time, and losing the huge diversity that's present there now.

I like how you layer it on with a nice chunk of anti-research and anti-government paranoia. Though it's kind of entertaining that you thing researchers do it for the money.

Most know nothing.

[Charcharodon]

The reef is nothing more than the dead skeletons of corals. It is not "alive" The living portion of the reef, is just the top few centimeters. They do not take millions of years to form, they take weeks/months/years to form, much like plants on land. They thrive where ever the conditions are right. When the conditions change the corals die, and the reef becomes barren. That is not the end of the story as the political eco opportunists would have you believe. The spawning methods of corals literally cast their offspring everywhere so there is always corals trying to establish new reefs in nearly every part of the ocean. As the conditions change new areas become habitable for the corals and their numbers will rapidly grow.

If things swing back the other way dead corals will bounce back within a year or two.

Now specific man-made problems such as silting, runoff, fishing, recreational diving, and anchor dragging and kill off corals in an area and should be addressed as solvable solutions. Trying fight climate change well that is just pissing into the wind. Even without the so called global warming caused by mankind the reefs were going to die off and relocated anyway.