A new study by Monash University researchers published in Nature Microbiology has found that two common gases, hydrogen and carbon monoxide, sustain trillions of bacteria in the deep ocean.
The five-year study led by Dr. Rachael Lappan and Professor Chris Greening of the Biomedicine Discovery Institute discovered that chemosynthesis, not photosynthesis, is the dominant method for growth in the deepest areas of the ocean. The team combined chemical measurements during oceanic voyages with laboratory-based microbial culture characterizations and used metagenomic sequencing to determine the genetic blueprints of the microbes present. The researchers found that hydrogen consumption genes are present across eight different types of microbes, and this survival strategy becomes more common as the depth increases.
The surface layers of the ocean contain high levels of dissolved hydrogen and carbon monoxide gases, which oceanic bacteria use for energy like their terrestrial cousins. These findings suggest that the first life on Earth likely emerged in deep-sea vents using hydrogen as its energy source, not sunlight.