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Upside of dinosaur extinction: Life came back to the asteroid’s crater very quickly


Coffee Time Okay, it wasn’t good news for the dinosaur. Still, as earth scientist Scott K. Johnson tells it at Ars Technica, reporting on a find from the Chicxulub Crater hit 66 million years ago:

Usually, new studies of the dino-killing mass extinction at the end of the Cretaceous provide another view into just how bloody awful it was. But if you’re a glass-half-full kind of person, it’s interesting to think about how quickly life recovered—not on timescales relevant to an individual organism, necessarily, but in terms of species and ecosystems.

While the lower part of the brown limestone contains just older fossils that were kicked up with the rest of the mud, the upper part of this layer contains tiny worm burrows that shows things were living there while the mud was still settling. Tiny fossilized foraminifera species known to have survived the mass extinction also start showing up in the upper part of this layer. That would mean life returned to the crater within a matter of years.

In the white layer of limestone above, which probably begins recording history 30,000 years after the impact, the diversity and number of tiny fossils increases considerably. And measurements of barium, titanium, and iron show that the mass of growing life was much higher, as well. This evidence paints a picture of a healthy, productive ecosystem that had basically returned to “normal” function (minus the species that disappeared, of course). That’s much faster than the 300,000 years it took elsewhere in the Gulf of Mexico or Atlantic. More.

One thing that makes enviro-doomsaying vaguely unbelievable is the fact that life forms, taken as a group, tend to creep back into devastated areas quickly. The problem isn’t that life on Earth will be wiped out but that the life forms we care about, which tend to be more vulnerable than the ones we don’t care about, might be wiped out. If 2,000 varieties of fungi disappeared in the asteroid hit – assuming we knew about them –  how much ink would they get compared to the tyrannosaur or the stegosaur?

See also: Startling Result–90% of Animals Less than 200 kya

Endangered giant Chinese salamander is at least five different “species”


Butterfly “extinction” that wasn’t

News, completely off topic but you might want to link to this in an OP. http://www.cbc.ca/news/indigenous/residential-school-trauma-epigenetics-1.4681966 Allan Keith
"not on timescales relevant to an individual organism, necessarily.." That doesn't give nearly enough credit to the irresistible force of life. Similar examples in recent years, like Mt St Helens and Chernobyl, started to recover INSTANTLY and were flourishing again in a few years. Of course the organisms that were killed by the disaster couldn't appreciate the recovery, but their cohorts moved back in. polistra

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