Sulfur finding may hold key to Gaia theory of Earth as living organism

Is Earth truly a kind of giant living organism as the Gaia hypothesis predicts? A new discovery made at the University of Maryland might supply a key to answering this query. This important of sulfur could let scientists to unlock heretofore hidden interactions amongst ocean organisms, atmosphere, and land — interactions that may give evidence supporting this renowned 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 kind 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 steady ample against oxidation in water to enable 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 probable candidate for this function was deemed to be dimethylsulfide.

Newly published work completed at the University of Maryland by first writer Harry Oduro, together with UMD geochemist James Farquhar and marine biologist Kathryn Van Alstyne of Western Washington University, supplies a device for tracing and measuring the movement of sulfur through ocean organisms, the atmosphere and the land in ways that may help show or disprove the controversial Gaia theory. Their study seems 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 distinctions in the isotope ratios of these two sulfur compounds that are developed 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 environment.

Sulfur, the tenth most abundant component in the universe, is element of numerous inorganic and organic compounds. Sulfur cycles sulfur through the land, environment and residing items and plays vital roles in each climate and in the health of organisms and ecosystems.

“Dimethylsulfide emissions play a function in climate regulation through transformation to aerosols that are believed to influence the Earth’s radiation balance,” says Oduro, who conducted the research whilst finishing a Ph.D. in geology & earth system sciences at Maryland and now is a postdoctoral fellow at the Massachusetts Institute of Engineering. “We show that differences in isotopic composition of dimethylsulfide could differ in ways that will help us to refine estimates of its emission into the atmosphere and of its cycling in the oceans.”

As with a lot of other chemical components, sulfur consists of various isotopes. All isotopes of an component are characterized by getting the very same amount of electrons and protons but diverse numbers of neutrons. For that reason, isotopes of an component are characterized by identical chemical properties, but distinct mass and nuclear properties. As a result, it can be feasible for scientists to use distinctive 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 sulfur isotopic composition of these two sulfur compounds,” says Farquhar, a professor in the University of Maryland’s department of geology. “This was a quite tough measurement to do appropriate, and his measurements exposed an unexpected variability in an isotopic signal that seems to be connected to the way the sulfur is metabolized.

“Harry’s work establishes that we should anticipate to see variability in the sulfur isotope signatures of these compounds in the oceans underneath diverse environmental circumstances and for diverse organisms. I think this will in the end be extremely important for making use of isotopes to trace the cycling of these compounds in the surface oceans as well as the flux of dimethylsulfide to the environment. The potential to do this could support us answer crucial climate inquiries, and ultimately greater predict climate modifications. And it could even aid us to greater trace connections among dimethylsulfide emissions and sulfate aerosols, eventually testing a coupling in the Gaia hypothesis,” Farquhar says.


Sources and more information:

• Tracking Ocean Sulfur Could Help Test Gaia Hypothesis

By Duncan Geere, Wired UK Geologists at the University of Maryland have published research that could help prove or disprove Gaia theory – the notion that the Earth is one single self-regulating system. The concept dates from the 70s and was initially formulated by James Lovelock and Lynn Margulis.

• UMD finding may hold key to Gaia hypothesis

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…

• Tracking ocean sulphur could help validate Gaia theory

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