Anaerobic ammonium oxidation in the Peruvian oxygen minimum zone
2007; Wiley; Volume: 52; Issue: 3 Linguagem: Inglês
10.4319/lo.2007.52.3.0923
ISSN1939-5604
AutoresM. Robert Hamersley, Gaute Lavik, Dagmar Woebken, Jayne E. Rattray, Phyllis Lam, Ellen C. Hopmans, Jaap S. Sinninghe Damsté, Siegfried Krüger, Michelle Graco, Dimitri Gutiérrez, Marcel M. M. Kuypers,
Tópico(s)Tracheal and airway disorders
ResumoWe investigated the microbial pathways of nitrogen (N) loss in an April 2005 transect through the Peruvian oxygen minimum zone (OMZ) at 12°S latitude using short anaerobic incubations with 15 N‐labeled substrates and molecular‐ecological and lipid‐biomarker studies. In incubations with 15 NH 4 + , immediate production of 14 N 15 N, but not 15 N 15 N, indicated that N 2 was produced by the pairing of labeled 15 NH 4 + with in situ 14 NO 2 − via anaerobic ammonium oxidation (anammox). Supporting this finding, we also found anammox‐related 16S ribosomal ribonucleic acid gene sequences similar to those previously known from other marine water columns in which anammox activity was measured. We identified and enumerated anammox bacteria via fluorescence in situ hybridization and quantitative polymerase chain reaction and found ladderane membrane lipids specific to anammox bacteria wherever anammox activity was measured by our isotope tracer method. However, in incubations with 15 NO 3 − or 15 NO 2 − , in which denitrification would have been expected to produce 15 N 15 N by pairing of oxidized 15 N ions, 15 N 15 N production was not detected before 24 h, showing that denitrification of fixed N to N 2 was not taking place in our samples. At the time and locality of our study, anammox, rather than denitrification, was responsible for N 2 production in the Peruvian OMZ waters.
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