Planktonic Euryarchaeota are a significant source of archaeal tetraether lipids in the ocean

Sara A. Lincoln*, Brenner Wai, John M. Eppley, Matthew J. Church, Roger E. Summons, Edward F. DeLong

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

102 Citations (Scopus)

Abstract

Archaea are ubiquitous in marine plankton, and fossil forms of archaeal tetraether membrane lipids in sedimentary rocks document their participation in marine biogeochemical cycles for >100 million years. Ribosomal RNA surveys have identified four major clades of planktonic archaea but, to date, tetraether lipids have been characterized in only one, the Marine Group I Thaumarchaeota. The membrane lipid composition of the other planktonic archaeal groups - all uncultured Euryarchaeota - is currently unknown. Using integrated nucleic acid and lipid analyses, we found that Marine Group II Euryarchaeota (MG-II) contributed significantly to the tetraether lipid pool in the North Pacific Subtropical Gyre at shallow to intermediate depths. Our data strongly suggested that MG-II also synthesize crenarchaeol, a tetraether lipid previously considered to be a unique biomarker for Thaumarchaeota. Metagenomic datasets spanning 5 y indicated that depth stratification of planktonic archaeal groups was a stable feature in the North Pacific Subtropical Gyre. The consistent prevalence of MG-II at depths where the bulk of exported organic matter originates, together with their ubiquitous distribution over diverse oceanic provinces, suggests that this clade is a significant source of tetraether lipids to marine sediments. Our results are relevant to archaeal lipid biomarker applications in the modern oceans and the interpretation of these compounds in the geologic record.

Original languageEnglish
Pages (from-to)9858-9863
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume111
Issue number27
DOIs
Publication statusPublished - 8 Jul 2014
Externally publishedYes

Keywords

  • euryarchaea
  • glycerol dialkyl glycerol tetraether
  • oceanography
  • environmental genomics
  • TEX₈₆ index

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