Science & Nature How Life on Our Planet Made It Through Snowball...

How Life on Our Planet Made It Through Snowball Earth

-

- Advertisment -

Science|How Life on Our Planet Made It Through Snowball Earth

research published Monday in Proceedings of the National Academy of Sciences, Dr. Planavsky and his colleagues report the discovery of oases just beneath the ancient ice sheets that likely helped life persevere.

Snowball Earth came to an abrupt end over a half-billion years ago, but its marks still exist in remote corners of the planet. In 2015, to reach one of those corners, Max Lechte and his graduate adviser at the time, Malcolm Wallace, both sedimentologists at the University of Melbourne, drove 15 hours into the South Australian outback.

They trekked over hills made of red-colored rock, and it was so hot out — about 122 degrees Fahrenheit — that the soles of Dr. Wallace’s boots melted.

“A bit of duct tape fixed that up,” said Dr. Lechte, who led the new research.

These red-hot rocks formed in the oceans during the snowball glaciations, and their color caught Dr. Lechte’s eye, so he took a few samples. Then, in 2015 and 2016, he traveled to Namibia and Death Valley in California and found more rocks — also red — that formed at the same time.

The rocks’ color signaled to Dr. Lechte that they are rich in iron, which means they turned red for the same reason that old cars with iron exteriors turn red: They rusted.

Oxygen needs to be present for iron to rust. It also needs to be present for animals and many other organisms to survive. If the iron rocks below the ancient oceans rusted, then there was also oxygen in those oceans. And if there was oxygen, then oxygen-breathing life-forms had a lifeline they could cling to.

“This is the first direct evidence for oxygen-rich marine environments during Snowball Earth,” said Dr. Lechte, now a postdoctoral researcher at McGill University in Canada.

But how that oxygen got into the oceans in the first place was a mystery. The atmosphere is a major source of oxygen for the oceans, and with the ice sheets of Snowball Earth acting as giant air-blocking shields, oxygen in seawater should’ve been nonexistent.

“This could’ve led to anoxic oceans, which could’ve killed off life-forms that need oxygen to survive.” Dr. Lechte said. “It presents a bit of an unsolved problem.”

In labs at Yale as well as Nanjing University in China, Dr. Lechte and his team crushed the iron-rich rocks, dissolved them in acid and measured the abundances of different iron isotopes. They found that the iron in rocks that formed far out in the open oceans rusted much less than the iron in rocks that formed closer to land, right where ice sheets dove from continents and into the oceans.

Today, beneath ice sheets in Antarctica, glacial meltwater streams flow into the Southern Ocean. That water melts from ice that can have air bubbles trapped inside it, and those bubbles can seed the meltwater streams with oxygen. On Snowball Earth, Dr. Planavsky explained, such oxygen-laden streams flowed into the oceans around the edges of continents and sustained life.

Paul Hoffman, a geologist at Harvard University who pioneered the Snowball Earth hypothesis, thinks this idea for how oxygen made it into the oceans is solid. “I’m attracted to the idea, and I think it’s consistent with my own observations,” he said.

But, Dr. Hoffman added, whether or not this oxygen pump was the main thing that helped many living things survive those ice ages is still an open question.

“We just don’t know enough from a theoretical standpoint about how life would have responded to the challenge of a Snowball Earth,” he said.

The New York Times: Continue reading…

Latest news

Fans react to Billy Magnussen Aladdin spinoff after Mena Massoud news

Welcome! Meredith collects data to deliver the best content, services, and personalized digital ads. We partner with third party advertisers, who may use tracking technologies to collect information about your activity on sites and applications across devices, both on our sites and across the Internet. You always have the choice to experience our sites without…

Ron Leibman dead: Friends, Angels in America actor dies at 82

Welcome! Meredith collects data to deliver the best content, services, and personalized digital ads. We partner with third party advertisers, who may use tracking technologies to collect information about your activity on sites and applications across devices, both on our sites and across the Internet. You always have the choice to experience our sites without…

Caitlyn Jenner enjoys beach stroll with partner Sophia Hutchins following I’m A Celebrity exit

Caitlyn Jenner, 70, nails off-duty chic as she enjoys beach stroll with abs-flashing partner Sophia Hutchins, 23, in Australia following her lonely I'm A Celebrity exitBy Jabeen Waheed For Mailonline Published: 15:41 GMT, 7 December 2019 | Updated: 16:36 GMT, 7 December 2019 Caitlyn Jenner was seen enjoying a low-key stroll with her partner Sophie…

ARMY Trends #BTSxJingleBall for BTS’s Jingle Ball Performance

On Dec. 6, BTS performed at iHeartRadio’s KIIS Jingle Ball. The Korean band opened the show with three songs with some of the loudest cheers of the night. On Twitter, ARMY trended #BTSxJingleBall worldwide to celebrate the group’s performance. BTS | Kevin Winter/Getty Images for iHeartMediaBTS opened KIIS Jingle Ball At KIIS Jingle Ball, BTS…
- Advertisement -

Fans react to Billy Magnussen Aladdin spinoff after Mena Massoud news

Welcome! Meredith collects data to deliver the best content, services, and personalized digital ads. We partner with third party advertisers, who may use tracking technologies to collect information about your activity on sites and applications across devices, both on our sites and across the Internet. You always have the choice to experience our sites without…

Ron Leibman dead: Friends, Angels in America actor dies at 82

Welcome! Meredith collects data to deliver the best content, services, and personalized digital ads. We partner with third party advertisers, who may use tracking technologies to collect information about your activity on sites and applications across devices, both on our sites and across the Internet. You always have the choice to experience our sites without…

Must read

- Advertisement -

You might also likeRELATED
Recommended to you