Dinosaurs Not Killed By Blast -- But By Acid Rain?
Posted by
Hemos
on from the flip-flop-flip-flop dept.
JCMay writes "FoxNews is reporting that it wasn't just the impact of a ten-mile wide asateroid in Mexico that killed off the dinosaurs, but rather the chemicals kicked up-- mostly carbon dioxide and many sulfur-bearing compounds."
Re:problem with this theory
by
bcrowell
·
· Score: 3
A standard argument against the giant impact theory of the extinction was always that certain critters, e.g. dinosaurs, went extinct, while others, e.g. reptiles, didn't. Same thing with plankton -- some bought the farm, but other very similar species survived.
The evidence is very strong that there was a giant impact, but it doesn't completely explain the pattern of extinctions. However, there was an interesting recent case where someone studied the area around a volcano that had erupted (was it Mt. St. Helens??) and found that it was surprisingly random what plants got the first toeholds in the newly sterilized area.
People who disbelieve the giant impact explanation say it's straightforward: a crocodilian species and a dinosaur species might have been competing in the same ecological niche. One won, the other lost.
If this theory were true, wouldn't that mean that many other organisms other than the dinosaurs were killed? I mean, the article talks about highly toxis "globs" of sulfuric acid throughout the atmosphere. I strongly doubt anything more complicated that certain prokaryotes could survive that!
I guess it's all a matter of how concentrated the toxins are and how robust different parts of the ecology are. Kill off all the green plants, and the whole animal food chain gets pretty much destroyed. Then new plants grow from seed.
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The evidence is very strong that there was a giant impact, but it doesn't completely explain the pattern of extinctions. However, there was an interesting recent case where someone studied the area around a volcano that had erupted (was it Mt. St. Helens??) and found that it was surprisingly random what plants got the first toeholds in the newly sterilized area.
People who disbelieve the giant impact explanation say it's straightforward: a crocodilian species and a dinosaur species might have been competing in the same ecological niche. One won, the other lost.
If this theory were true, wouldn't that mean that many other organisms other than the dinosaurs were killed? I mean, the article talks about highly toxis "globs" of sulfuric acid throughout the atmosphere. I strongly doubt anything more complicated that certain prokaryotes could survive that!
I guess it's all a matter of how concentrated the toxins are and how robust different parts of the ecology are. Kill off all the green plants, and the whole animal food chain gets pretty much destroyed. Then new plants grow from seed.
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