I never quite understood that the Gaia Hypothesis allowed specific
predictions. I thought at the time that the premise was self evident
and a nice idea, but likely unprovable. Since then I have come to
understand that communication at the cellular level could be as
interconnected as our internet and most likely is. The problem as
you might well appreciate is always to figure out just what to do
with it all.
This work establishes that tracking sulfur isotope differentiation
through land, sea and air could allow us to piece together one of the
key predictions made from the Gaia Hypothesis.
A Gaia paradigm encourages responsible husbandry, sorely lacking in
the past and now steadily gathering momentum in the other direction.
Mankind is slowly relearning that his central role in terms of living
on Terra is to provide good husbandry.
New finding may
hold key to Gaia hypothesis of Earth as living organism
May 15, 2012
(Phys.org) -- Is Earth
really a sort of giant living organism as the Gaia hypothesis
predicts? A new discovery made at the University of Maryland may
provide a key to answering this question. This key of sulfur could
allow scientists to unlock heretofore hidden interactions between
ocean organisms, atmosphere, and land -- interactions that might
provide evidence supporting this famous theory.
The Gaia hypothesis --
first articulated by James Lovelock and Lynn Margulis in the 1970s --
holds that Earth's physical and biological processes are inextricably
connected to form a self-regulating, essentially sentient, system.
One of the early
predictions of this hypothesis was that there should be a sulfur
compound made by organisms in the oceans that was stable enough
against oxidation in water to allow its transfer to the air. Either
the sulfur compound itself, or its atmospheric oxidation product,
would have to return sulfur from the sea to the land surfaces. The
most likely candidate for this role was deemed to be dimethyl
sulfide.
Newly published work
done at the University of Maryland by first author Harry Oduro,
together with UMD geochemist James Farquhar and marine
biologist Kathryn Van Alstyne of Western Washington University,
provides a tool for tracing and measuring the movement of sulfur
through ocean organisms, the atmosphere and the land in ways that may
help prove or disprove the controversial Gaia theory. Their study
appears in this week's Online Early Edition of the Proceedings
of the National Academy of Sciences (PNAS).
According to Oduro and
his colleagues, this work presents the first direct measurements of
the isotopic composition of dimethylsulfide and of its precursor
dimethylsulfoniopropionate. These measurements reveal differences
in the isotope ratios of these two sulfur compounds that
are produced by macroalga and phytoplankton. These measurements
(1) are linked to the compounds' metabolism by these ocean organisms
and (2) carry implications for tracking dimethylsulfide emissions
from the ocean to the atmosphere.
Sulfur, the tenth most
abundant element in the universe, is part of many inorganic and
organic compounds. Sulfur cycles sulfur through the land, atmosphere
and living things and plays critical roles in both climate and in the
health of organisms and ecosystems.
"Dimethylsulfide
emissions play a role in climate regulation through transformation to
aerosols that are thought to influence the earth's radiation
balance," says Oduro, who conducted the research while
completing a Ph.D. in geology & earth system sciences at Maryland
and now is a postdoctoral fellow at the Massachusetts Institute of
Technology. "We show that differences in isotopic composition of
dimethylsulfide may vary in ways that will help us to refine
estimates of its emission into the atmosphere and of its cycling in
the oceans."
As with many other
chemical elements, sulfur consists of different isotopes. All
isotopes of an element are characterized by having the same number of
electrons and protons but different numbers of neutrons. Therefore,
isotopes of an element are characterized by identical chemical
properties, but different mass and nuclear properties. As a result,
it can be possible for scientists to use unique combinations of an
element's radioactive isotopes as isotopic signatures through which
compounds with that element can be traced.
"What Harry did
in this research was to devise a way to isolate and measure the
sulfurisotopic composition of these two sulfur compounds,"
says Farquhar, a professor in the University of Maryland's department
of geology. "This was a very difficult measurement to do right,
and his measurements revealed an unexpected variability in an
isotopic signal that appears to be related to the way the sulfur is
metabolized.
"Harry's work
establishes that we should expect to see variability in
the sulfur isotope signatures of these compounds in the
oceans under different environmental conditions and for different
organisms. I think this will ultimately be very important for using
isotopes to trace the cycling of these compounds in the surface
oceans as well as the flux of dimethylsulfide to the atmosphere. The
ability to do this could help us answer important climate questions,
and ultimately better predict climate changes. And it may even help
us to better trace connections between dimethylsulfide emissions and
sulfate aerosols, ultimately testing a coupling in the Gaia
hypothesis," Farquhar says.
More information:
http://www.pnas
Journal reference:
Proceedings of the National Academy of Sciences Provided by
University of Maryland
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