Finding microbes living deep underground is surprising, although it's happened before. But researchers were very surprised to find cyanobacteria, which normally requires light for photosynthesis, living in deeply-buried rock in Spain. A team led by Fernando Puente-Sánchez of the Spanish Centre of Astrobiology in Madrid dug a borehole 2011 feet deep and examined the sample they brought up. The presence of cyanobacteria was so unexpected, they dug another hole to control for contamination. The cyanobacteria was there, also.
So what’s going on? How can these microorganisms survive at such extreme depths with no access to sunlight and scant traces of water?
Observed through a microscope, the subterranean cyanobacteria appeared similar to their cousins that live on the surface. Genetic analysis, however, told a slightly different story; the enigmatic cyanobacteria produce enzymes that convert hydrogen into useful energy. And revealingly, the researchers observed lower levels of hydrogen within the air pockets of the rocks where the cyanobacteria lived compared to areas in which they were absent. This suggests the underground microbes are consuming hydrogen gas to get their fuel.
The discovery is all the more weird because species without access to light and water are thought to have restricted opportunity for mutation and evolution. But life, uh, finds a way. Read more about the underground cyanobacteria at Gizmodo.
(Image credit: PNAS)