Life rebounded just years after the dinosaur-killing asteroid struck

[Judi Lynn]

By Katherine Kornei
May. 30, 2018 , 1:00 PM

When a 10-kilometer-wide asteroid hit the Gulf of Mexico 66 million years ago, it drove over 75% of Earth’s species to extinction, including the dinosaurs. But within just a few years, life returned to the submerged impact crater, according to a new analysis of sediments in the crater. Tiny marine creatures flourished thanks to the circulation of nutrient-rich water. That return of life could offer lessons in how marine ecosystems might recover after the dramatic shifts caused by climate change, the researchers suggest.

The new findings reveal “how resilient life can be,” says Gareth Collins, a planetary scientist at Imperial College London who was not involved in the research. “Such a rapid recovery … is remarkable.”

Some scientists hypothesize that life might slowly creep back into impact craters, perhaps because of toxic metals such as mercury and lead scattered by the impact. Other impact craters tell a tale similar to that idea: The 85-kilometer Chesapeake Bay crater, for instance, was devoid of life for thousands of years after a comet or asteroid hit modern-day Virginia some 35 million years ago.

As part of an effort to understand how planets respond to large impacts, a team of scientists in 2016 drilled into the 180-kilometer Chicxulub crater, the only impact structure linked to a global extinction event. The team brought up hundreds of roughly arm-length sediment cores. Some bore the scars of the extreme temperatures and pressures of the event, which drove rocks to behave like a fluid: Mountains the height of the Himalayas rose and fell within the span of minutes. One core, taken from roughly 600 meters below the modern sea floor, contained 76 centimeters of dull brown limestone—not much to look at, but perhaps the most treasured swath of sediment from the entire drilling project, at least to Chris Lowery.

More:
http://www.sciencemag.org/news/2018/05/life-rebounded-just-years-after-dinosaur-killing-asteroid-struck

Science:
https://www.democraticunderground.com/122857590



Chicxulub crater


More images:

https://tinyurl.com/ybqdrt9g