Two Billion Years Ago, up to 99 Percent of Life on Earth Died in an Event More Catastrophic Than Mass Extinction of the Dinosaurs

Via:  freefaller  •  2 weeks ago  •  24 comments

Two Billion Years Ago, up to 99 Percent of Life on Earth Died in an Event More Catastrophic Than Mass Extinction of the Dinosaurs

S E E D E D   C O N T E N T

Scientists have discovered a mass die-off that took place two billion years ago—with up to 99.5 percent of life on Earth disappearing. The massive die-off saw more of the planet's biosphere vanish than when the dinosaurs were wiped off the face of the planet 65 million years ago, researchers say.

Normally, massive die-off events can be tracked through the fossil record—animals exist, then they do not. However, in times before complex life existed, understanding these events becomes more difficult—the microorganisms that made up the planet's biota cannot be traced in the same way.

In a study published in PNAS, an international team of scientists examined rocks from Hudson Bay, Canada, that would have formed billions of years ago. They were looking at barite, a mineral that holds information about how much oxygen was in the atmosphere at a given time.

From these rocks, the team was able to show that there was a massive drop in the level of life on Earth 2.05 billion years ago. This coincided with major changes to the oxygen levels on the planet—prior to the die-off, about 2.4 billion years ago, there was a massive surge in the amount of oxygen in the atmosphere. At the end of this event—which is known as the Great Oxidation Event—oxygen levels fell dramatically. Researchers say conditions for life on Earth went from "feast to famine"—and that these conditions persisted for about one billion years.

"We were very surprised," study author Peter Crockford, from Israel's Weizmann Institute of Science and Princeton University, told Newsweek. "We didn't expect to see such a large signal, nor did we expect to find it in this specific type of sample.

"Over the 100 to 200 million years before this die-off event there was a large amount of life on the planet, but after this event a huge portion died off. However, instead of recovering like more recent mass extinctions, the amount of life on the planet or size of the biosphere stayed small for the following billion years of Earth's history—about two billion to one billion years ago."

He continued: "From our estimates it could be anywhere between about 99.5 percent to 80 percent of life on the planet died off around two billion years ago." To put that in perspective, the mass extinction event of the dinosaurs saw about three-quarters of life on Earth disappear, while the Great Dying event—the biggest known mass extinction—resulted in the loss of around 70 percent of terrestrial life and 96 percent of ocean dwellers.

The findings, the team say, provides support for the idea of an "oxygen overshoot"—a theory that says photosynthesis and weathering produced a massive amount of oxygen that spurred the development of life on Earth. However, the oxygen-emitting organisms on Earth were then so abundant they exhausted their nutrient supply and numbers fell

Crockford said their discovery could give an insight into how Earth will change in the future: "Just like two billion years ago, the biosphere today (including us) relies on the base of the food chain. Today, that is microorganisms in the ocean and plants on land. Although oxygen levels will likely never change at a pace fast enough to a level significant enough for humans to take much notice, they could absolutely change over the next billion years."

He also said he believes there are probably far more major die-off events and mass extinctions that we do not yet know about. "The problem is that the geologic record gets poorer and poorer the further back we look, so we need to combine lots of different tools and intensely interrogate the samples that we have available to translate the rock record into a picture of what the Earth used to look like."

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1  seeder  Freefaller    2 weeks ago

While obviously more study is needed, this is another example of just how precarious life is.

Imagine how different life on this planet would be if this (or any other) extinction event had not happened

Freedom Warrior
1.1  Freedom Warrior  replied to  Freefaller @1    2 weeks ago

Which kinda gives us good reason not to become preoccupied with extinction events in our future.

1.1.1  seeder  Freefaller  replied to  Freedom Warrior @1.1    2 weeks ago

In your opinion

1.1.2  Gordy327  replied to  Freedom Warrior @1.1    2 weeks ago

Why not? The next mass extinction event could involve humans, especially if humans contribute to the cause. 

Freedom Warrior
1.1.3  Freedom Warrior  replied to  Gordy327 @1.1.2    2 weeks ago

 So what are you worried about?

1.1.4  Gordy327  replied to  Freedom Warrior @1.1.3    one week ago

I'd prefer if humans did not go extinct, especially by our own hands. But that's just me.

Freedom Warrior
1.1.5  Freedom Warrior  replied to  Gordy327 @1.1.4    one week ago

 No reason to worry about that 

1.2  FLYNAVY1  replied to  Freefaller @1    2 weeks ago

We as a species have to get off of this rock if we have any hope of preserving our species.

1.2.1  Ronin2  replied to  FLYNAVY1 @1.2    2 weeks ago

We need to increase is our adaptability as a species.

Unless there is a massive technological breakthrough; it might be hundreds of years before we are even able to leave the solar system. It took Voyager 36 years to leave the solar system. That is far too long for humans to live in space. It would take 81,000 years to reach the next solar system 4.24 light years away.  That is simply unrealistic.

Better to concentrate on adapting to the changing conditions on this planet; and possibly trying to terraform some of the surrounding asteroids/moons in our galaxy that might be able to sustain life.

1.3  WallyW  replied to  Freefaller @1    2 weeks ago

All of these extinction events led to conditions that allowed we humans to evolve.

It showed that, once established, life is resilient and tends to persist.

1.3.1  seeder  Freefaller  replied to  WallyW @1.3    2 weeks ago
All of these extinction events led to conditions that allowed we humans to evolve.

I know, pretty cool that through some (many) rolls of the cosmic dice here we are 

It showed that, once established, life is resilient and tends to persist.

That it does in some form or another

Freedom Warrior
1.3.2  Freedom Warrior  replied to  WallyW @1.3    2 weeks ago

 Precisely my point.

1.4  SteevieGee  replied to  Freefaller @1    2 weeks ago

So...  Since a reduction in oxygen in the atmosphere caused the death of 99% of life here is it a good idea to pump billions of tons of co2 and hydrocarbons into the air while burning the rain forests?

Freedom Warrior
1.4.1  Freedom Warrior  replied to  SteevieGee @1.4    2 weeks ago

It's a regenerative cycle. Make take a few billion years but that's life on planet earth.

1.4.2  seeder  Freefaller  replied to  SteevieGee @1.4    one week ago

Steevie current and future are not the topic, past mass extinctions are.  However I believe my opinion has been clear on other more relevant seeds

2  dave-2693993    2 weeks ago

Not sure what happened to my first post...anyhow:

It's like a Twilight Zone episode, the Rod Serling kind.

First guess prior to reading was the moon event. Guess not.

2.1  seeder  Freefaller  replied to  dave-2693993 @2    2 weeks ago
First guess prior to reading was the moon event.

Decent guess Dave, but that is thought to have happened very early in Earths history (say 4.5 billion yo)

2.1.1  dave-2693993  replied to  Freefaller @2.1    2 weeks ago

Yes, you are right, that would be a little too far back.

3  Kavika     2 weeks ago

Great article, Freefaller.


Hold on, the earth is only 6,000 years old. This is a ''fake news'' article.../s

3.1  seeder  Freefaller  replied to  Kavika @3    2 weeks ago

Thanks Kavika I though it was interesting.  But be nice, this is a science article and I don't want anything to attract the creationist.

3.1.1  Kavika   replied to  Freefaller @3.1    2 weeks ago

You're right. Sorry.

4  Enoch    2 weeks ago

Dear Friend Freefaller: Seems like checks and balances is a part of nature, not only good government.

Great article.

Most interesting and enlightening.

Thanks for posting.



4.1  seeder  Freefaller  replied to  Enoch @4    2 weeks ago

Enoch thank and agreed

4.1.1  Enoch  replied to  Freefaller @4.1    2 weeks ago

Most welcome, dear friend.


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