This certainly tightens up the linkage to the Siberian Traps in
providing an explanation for the Permian Extinction. A near
continuous influx of nickel rich ash would be feasible here. More
work needs to be done to tighten this up but it certainly looks good.
One thing that has not happened in human history is a serious flood
basalt that is regional in scope. However, what is operating in
Hawaii may in fact be as good as it actually gets. It may need a
massive impact to make a serious difference. I would like to see a
convincing study of these events that explains how they come to
surface at all when continents are supposed to be sitting on top of
them.
In the nonce we have workable time line and a causation agent. It
may well stand the test of time.
Was Earth’s most
devastating mass extinction caused by a single microbe?
Alasdair Wilkins
That's the intriguing
new hypothesis put forward to explain the Permian mass extinction,
which wiped out more than 90% of all Earth's species 251 million
years ago. And we even know which microbe is responsible
for this omnicidal annihilation.
MIT researcher Daniel
Rothman has proposed this idea based on his analysis of sediment
samples dating back to the very end of the Permian. The samples seem
to suggest that carbon levels rose very quickly, and no known
geological process — including a volcanic eruption or a meteorite
impact, two common explanations proposed for the Permian extinction —
could account for it. However, a microbe could account for that kind
of spike in carbon levels. Writing for New Scientist, Sara
Reardon explains how Rothman identified the likely culprit:
When Rothman's group
analysed the genome of Methanosarcina - a methanogen
responsible for most of Earth's biogenic methane today - they
discovered that the microbe gained this ability about 231 million
years ago. The date was close to that of the mass extinction, but not
close enough to suggest a link. But Methanosarcinaneeds large
amounts of nickel to produce methane quickly. When the team went back
to their sediment cores, they discovered that nickel levels spiked
almost exactly 251 million years ago - probably because the Siberian
lavas were rich in the metal.
Of course, this
hypothesis is far from confirmed, and the dates in the geological
will probably need to line up better than that before this really
starts gaining credence. Either way,Methanosarcina wouldn't have
been able to devastate Earth's biosphere if not for the availability
of that nickel-rich lava, so the volcanoes aren't off the hook here
just yet. But, if this is true, then I think Methanosarcina has
taken a very strong step towards being the biggest assholes in the
history of our planet. Then again, biologists are pretty much certain
that we humans are driving the current loss of biodiversity that
might well become the next mass extinction... so we're not exactly
off the hook either.
No comments:
Post a Comment