Microbial diversity in the deep sea and the underexplored “rare biosphere”

The evolution of marine microbes over billions of years predicts that the composition of microbial communities should be much greater than the published estimates of a few thousand distinct kinds of microbes per liter of seawater. By adopting a massively parallel tag sequencing strategy, we show that bacterial communities of deep water masses of the North Atlantic and diffuse flow hydrothermal vents are one to two orders of magnitude more complex than previously reported for any microbial environment. A relatively small number of different populations dominate all samples, but thousands of low-abundance populations account for most of the observed phylogenetic diversity. This "rare biosphere" is very ancient…

• NS
  National Science Foundation

  Awards: P50 ES012742, 0430724
• NA
  National Aeronautics and Space Administration

  Award: NNA04CC04A
• AP
  Alfred P. Sloan Foundation
• NI
  National Institutes of Health
• NI
  National Institute of Environmental Health Sciences

  Awards: P50 ES012742, 1 P50 ES012742
• NP
  NOAA Pacific Marine Environmental Laboratory