Archaeal dominance in the mesopelagic zone of the Pacific Ocean

  • Karner M
  • Delong E
  • Karl D
  • 501


    Mendeley users who have this article in their library.
  • 860


    Citations of this article.


The ocean's interior is Earth's largest biome. Recently, cultivation-independent ribosomal RNA gene surveys have indicated a potential importance for archaea in the subsurface ocean. But quantitative data on the abundance of specific microbial groups in the deep sea are lacking. Here we report a year-long study of the abundance of two specific archaeal groups (pelagic euryarchaeota and pelagic crenarchaeota) in one of the ocean's largest habitats. Monthly sampling was conducted throughout the water column (surface to 4,750 m) at the Hawai'i Ocean Time-series station. Below the euphotic zone (> 150 m), pelagic crenarchaeota comprised a large fraction of total marine picoplankton, equivalent in cell numbers to bacteria at depths greater than 1,000 m. The fraction of crenarchaeota increased with depth, reaching 39% of total DNA-containing picoplankton detected. The average sum of archaea plus bacteria detected by rRNA-targeted fluorescent probes ranged from 63 to 90% of total cell numbers at all depths throughout our survey. The high proportion of cells containing significant amounts of rRNA suggests that most pelagic deep-sea microorganisms are metabolically active. Furthermore, our results suggest that the global oceans harbour approximately 1.3 x 10(28) archaeal cells, and 3.1 x 10(28) bacterial cells. Our data suggest that pelagic crenarchaeota represent one of the ocean's single most abundant cell types.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Markus B. Karner

  • Edward F. Delong

  • David M. Karl

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free