Role for urea in nitrification by polar marine Archaea

• DOI: 10.1073/pnas.1201914109
• Publication Date: 2012-10-02T06:37:49Z
• Authors: Laura Alonso-Sáez; Alison S. Waller; Daniel R. Mende; Kevin Bakker; Hanna Farnelid; Patricia L. Yager; Connie Lovejoy; Jean-Éric Tremblay; Marianne Potvin; Friederike Heinrich; Marta Estrada; Lasse Riemann; Peer Bork; Carlos Pedrós-Alió; Stefan Bertilsson
• Keywords: Thaumarchaeota; Nitrogen Cycle; Biogeochemical Cycle; Autotroph

Despite the high abundance of Archaea in global ocean, their metabolism and biogeochemical roles remain largely unresolved. We investigated population dynamics metabolic activity Thaumarchaeota polar environments, where these microorganisms are particularly abundant exhibit seasonal growth. were more deep Arctic Antarctic waters grew throughout winter at surface deeper halocline waters. However, situ single-cell measurements revealed a low this group uptake both leucine bicarbonate (<5% cells active), which is inconsistent with known heterotrophic autotrophic thaumarchaeal lifestyles. These results suggested existence alternative sources carbon energy. Our analysis an environmental metagenome from that had pathways for ammonia oxidation and, unexpectedly, genes involved urea transport degradation. Quantitative PCR confirmed most potential to oxidize ammonia, large fraction them urease genes, enabling use fuel nitrification. higher than those near suggesting genetic differences between closely related archaeal populations. In concentration showed small-sized prokaryotes incorporated urea, availability was often ammonium. Therefore, degradation may be relevant pathway other exposed low-energy conditions dark