Sulfur played a vital role in the history of life on earth a new study says, and the fact that sulfur was abundant in the early earth, meaning plenty of material for microbes to metabolize to serve as fuel for photosynthesis, means that the abundance of sulfur in the early earth played a vital role in the oxygenation of the earth’s atmosphere.
However, because sulfur quickly degrades in an oxidized environment, the sulfur chemistry of early life on earth was “quickly lost to time,” as the article says.
Because sulfur is quickly oxidized in an oxygen-rich environment, and then removed from the atmosphere by precipitation and run-off into the ocean, the sulfur chemistry of early Archean life was phased out and lost to time. However, by understanding the mass independent fractionation process, it should be possible to learn more about the atmosphere of the pre-oxygenated Earth and the conditions in which the first life on Earth lived.
The process behind the mass independent fractionation of sulfur remains uncertain, but the two most popular hypotheses are either photolysis (the breaking apart of molecules) by ultraviolet light from the Sun, or reactions between elemental sulfur. “However, the actual phenomenon, reaction or mechanism is still to be identified,” says Dmitri Babikov, a Professor of Physical Chemistry and Molecular Physics at Marquette University in Milwaukee, Wisconsin.
The article says that sulfur isotopes could serve as potential indicators of environments similar to that of the early earth’s, but that today’s technology is too limited to be of any help in identifying such indicators in potential exoplanets. Let’s hope the Jim Webb telescope is launched soon, for much is yet to be learned about the universe at large.