In a puzzling extinction, something took out giant shark Megalodon and 36% of big marine animals generally.
A supernova 2.6 million years ago may be related to a marine megafaunal extinction at the Pliocene-Pleistocene boundary where 36 percent of the genera were estimated to become extinct. The extinction was concentrated in coastal waters, where larger organisms would catch a greater radiation dose from the muons.
According to the authors of the new paper, damage from muons would extend down hundreds of yards into ocean waters, becoming less severe at greater depths: “High energy muons can reach deeper in the oceans being the more relevant agent of biological damage as depth increases,” they write.
Indeed, a famously large and fierce marine animal inhabiting shallower waters may have been doomed by the supernova radiation.
“One of the extinctions that happened 2.6 million years ago was Megalodon,” Melott said. “Imagine the Great White Shark in ‘Jaws,’ which was enormous — and that’s Megalodon, but it was about the size of a school bus. They just disappeared about that time. So, we can speculate it might have something to do with the muons. Basically, the bigger the creature is the bigger the increase in radiation would have been.”
The KU researcher said the evidence of a supernova, or series of them, is “another puzzle piece” to clarify the possible reasons for the Pliocene-Pleistocene boundary extinction.
“There really hasn’t been any good explanation for the marine megafaunal extinction,” Melott said. “This could be one. It’s this paradigm change — we know something happened and when it happened, so for the first time we can really dig in and look for things in a definite way. We now can get really definite about what the effects of radiation would be in a way that wasn’t possible before.” Paper. (paywall) – Adrian L. Melott, Franciole Marinho, Laura Paulucci. Hypothesis: Muon Radiation Dose and Marine Megafaunal Extinction at the End-Pliocene Supernova. Astrobiology, 2018; DOI: 10.1089/ast.2018.1902 More.
Discussions about extinction these days don’t tend to focus so much on what the life form was supposed to be doing wrong but more on environment change that is too swift to adapt to. That makes sense, of course. But one wonders whether, one of these days, we will observe an extinction somewhat like this: The female spiders’ brains are infected by a virus that causes them to eat the males before rather than after mating. It’s something we’d have to see to believe but it could, after all, happen. 😉
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