Deep Hot Biosphere, Thomas Gold
nlandau at eden.rutgers.edu
Fri Jan 7 16:49:16 EST 2000
"Fred Pruyn" <pruyn at ad.nl> writes:
>But for those who read this book also: where could Gold be wrong in his
>assumptions that a still active biosphere is deep down the earth responsible
>for the formation of oil and coal? I am not in this field and like to have
>some more opinions, especially on his remarks about hopanoids.
I haven't read the book, but people have been discussing the possibility
of a deep-subsurface biosphere for quite some time. It is a perfectly
plausable hypothesis. There simply have not been very many observations
made to support it.
People started conjecturing about a chemically-driven deep biosphere
during the 1980s, when attention was turned to deep-ocean vents. Of
course, as far as anyone can tell, the vent ecosystems are driven
by reactions involving oxygen, which is a product of photosynthesis
(and so it makes them dependant on the surface biosphere). The guys
up at Pacific Northwest National labs made the first observations of
possibly independant deep ecosystems during the 1990s, when they
noticed that geochemically produced hydrogen was being used to
drive methanogenesis. This reaction is between CO2 and H2, neither of
which are produced by photosythesis.
I worked on that project for a while, before the Dept of Energy cut the
funding. We could grow cultures on basalt as the only energy source
in the absence of organic carbon. At least in the lab, organisms
are capable of growing given only sources of nutrients present in the
depths of the Columbia River Basalt.
The problem is demonstrating that this is occurring in the field. It
is difficult and costly to get samples from so deep underground.
The whole idea has passed out of vogue in the United States, due to
some politics in the microbial ecology community. Until we conduct
some good field studies, we won't be able to say whether subsurface
lithotrophic microbial ecosystems (SLiMEs) exist outside of the
Columbia River Basalt.
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