[Coral-List] Humans emulate prokaryotes

Charles Birkeland charlesb at hawaii.edu
Mon Apr 21 11:21:42 EDT 2014

The end of the Permian was the largest mass extinction in the fossil
record.  The massive increases in greenhouse gasses (GHGs) had previously
been attributed to the supervolcano that produced the Siberian traps, a
deposition of lava that covered an area the size of western Europe over a
km thick with some areas being up to 3500 m thick. However, if the GHGs
were from a volcano, they would have come in large bursts, tapering off
between bursts. The GHGs increased by "superexponential growth" which
indicated the main source of GHGs was biological rather than volcanic. A
paper by Rothman et al. in the April 15 issue of PNAS (vol. 111: 5462-5467)
identified methanogenic archaea as the culprits, having developed a new
metabolic pathway for the production of marine organic carbon to methane at
the end of the Permian.  The supervolcano was an accomplice by providing
massive amounts of nickel that removed the limitation by nickel and
catalyzed the expansion of methanogenic archaea.

I have repeatedly heard from microbiologists that prokaryotes run the world
and eukaryotes are just frosting.  Paleontologist Peter Ward in his book
"The Medea Hypothesis" argued that several mass extinctions were provided
by prokaryotes, and humans were the only eukaryote with population biology
like prokaryotes.  Hairston, Smith and Slobodkin (1960) espoused that
populations of eukaryotes were controlled either by predation or by
resource limitation. We immediately think of COTS, locusts, rats (e.g.,
Europe around 1348), and the lemmings of folklore as being occasionally
like humans in having populations out of control.  But COTS, locusts, rats,
and the legendary lemmings are only on a local scale. Humans and
prokaryotes can have global effects on the atmosphere and the ocean because
they can be innovative as well as lack the capacity of self-control.

Cyanobacteria developed photosynthesis which had global effects on the
atmosphere and oceans. This probably took place well over a billion years.
(We may look at these as positive changes, but the brethren of the time
probably felt it to be catastrophic.) Rothman et al. determined that a
methanogenic archaeon provided an innovation in efficient methane
production that facilitated the Permian mass extinction.  This took place
within 20,000 years.  Humans developed methods for profligate conversion of
fossil fuels to GHGs within three or four hundred years.  I hope the next
being with global powers has the wisdom to learn from the geologic record
and has the compassion to control itself for the sake of other living
beings  J

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