In the depths of the Joetsu Basin, Japan Sea, lies an abundance of methane hydrate, also known as “combustible ice”. It is produced when the natural gas methane combines with water, then freezes in low temperatures and high pressures. Mostly, the study of “combustible ice” has been to exploit its potential as an energy source, as it emits less waste-carbon than burning traditional fossil fuels. However, during this research, a microhabitat was unearthed.
Published in the journal Scientific Reports, scientists from the UK and Japan have collaboratively discovered evidence for the existence of life in the so-called “flammable ice” (it really does burn when you put a flame to it).
Dr Glen T. Snyder, lead author of the study from Meiji University in Japan, was melting the hydrate to study the methane gas released when he noticed a deposit left behind. Further study showed that these small spheroidal grains, called microdolomites, contained DNA.
The next piece of the puzzle came from an analysis by Dr Stephen Bowden from the University of Aberdeen. By looking at the microenvironments surrounding the grains in the methane hydrate, oil was shown to be degraded by bacteria. These "pockets" in the hydrate that contained the oil and microdolomites were also salty.
Bacteria appeared to feed off the oil, producing oxidized carbon in the process. The oxidized carbon, which is a key component of the microdolomites, was then used to continually grow the grain, aided by the salty surroundings. Inadvertently, the bacteria were building a home, of sorts, for themselves.
“The methane in ‘methane hydrate’ is known to form as microbes degrade organic matter on the seafloor,” explained Dr Snyder in a statement. “But what we never expected to find was microbes continuing to grow and produce these spheroids, all of the time while isolated in tiny cold dark pockets of saltwater and oil.”
“Even under near-freezing temperatures, at extremely high pressures, with only heavy oil and saltwater for food-sources, life was flourishing and leaving its mark,” Dr Bowden added.
Although the researchers were happy their findings provided a “positive spin to cold dark places”, they were even more intrigued by where else this microhabitat might exist.
“Providing they have ice and a little heat, all those frigid cold planets at the edge of every planetary system could host tiny microhabitats with microbes building their own ‘death stars’ and making their own tiny little atmospheres and ecosystems, just as we discovered here,” Dr Bowden theorized.