Four percent of the methane found in the earth’s atmosphere
comes from oceans. But for decades, researchers have been
flummoxed by how that could be. The only known biological source
of methane is a class of microorganisms that produce methane
when they are alive but die when exposed to oxygen. How could
these microorganisms, called methanogens, be so plentiful in the
oxygen-rich ocean? A new paper in the journal Science proposes a
plausible explanation for this seemingly impossible reality,
which is known as the ocean methane paradox. To back up a bit:
in 2008, David Karl, a researcher at the University of Hawaii,
and Edward DeLong, a researcher at M.I.T., had proposed that
marine microbes, always starved for phosphorus, can use
methylphosphonic acid to obtain this nutrient. Methane is a
byproduct of their absorption of phosphorus. The glaring problem
was that methylphosphonic acid had been found only in chemical
research labs, not in nature. William Metcalf, a professor of
microbiology at the University of