Bacteria are thriving on rocks right at the bottom of the ocean. In fact, they’re thriving by eating the rocks and they could be the biggest bacterial food web on the planet.
Cara Santelli and colleagues report in this week’s Nature that prokaryotic cell abundances on seafloor basalt rocks are between three and four orders of magnitude greater the sea water above them. Three orders of magnitude!
“Initial research predicted that life could in fact exist in such a cold, dark, rocky environment,” says Santelli (NSF press release). “But we really didn’t expect to find it thriving at the levels we observed.”
The team also looked at the bacterial diversity of the rocks and found it equivalent to that of farm soil. They looked at rocks around the East Pacific Rise and Hawaii and found the same thing at both locations.
“A 60,000-kilometre seam of basalt is exposed along the mid-ocean ridge spreading system, representing potentially the largest surface area for microbes to colonize on Earth,” says fellow author Katrina Edwards (USC press release).
As the Deep Sea News blog notes:
Take awhile for that to sink in…because what that means is that our understanding of carbon cycling and deep-sea systems is missing an entire food source and web.