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The production of nitric oxide by marine ammonia‐oxidizing archaea and inhibition of archaeal ammonia oxidation by a nitric oxide scavenger
Author(s) -
MartensHabbena Willm,
Qin Wei,
Horak Rachel E. A.,
Urakawa Hidetoshi,
Schauer Andrew J.,
Moffett James W.,
Armbrust E. Virginia,
Ingalls Anitra E.,
Devol Allan H.,
Stahl David A.
Publication year - 2015
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12677
Subject(s) - nitrification , anammox , archaea , ammonium , ammonia , environmental chemistry , biology , biogeochemical cycle , scavenger , nitrogen cycle , nitric oxide , nitrogen , denitrification , inorganic chemistry , biochemistry , chemistry , denitrifying bacteria , radical , organic chemistry , endocrinology , gene
Summary Nitrification is a critical process for the balance of reduced and oxidized nitrogen pools in nature, linking mineralization to the nitrogen loss processes of denitrification and anammox. Recent studies indicate a significant contribution of ammonia‐oxidizing archaea ( AOA ) to nitrification. However, quantification of the relative contributions of AOA and ammonia‐oxidizing bacteria ( AOB ) to in situ ammonia oxidation remains challenging. We show here the production of nitric oxide ( NO ) by N itrosopumilus maritimus SCM 1. Activity of SCM 1 was always associated with the release of NO with quasi‐steady state concentrations between 0.05 and 0.08 μM. NO production and metabolic activity were inhibited by the nitrogen free radical scavenger 2‐phenyl‐4,4,5,5,‐tetramethylimidazoline‐1‐oxyl‐3‐oxide ( PTIO ). Comparison of marine and terrestrial AOB strains with SCM 1 and the recently isolated marine AOA strain HCA 1 demonstrated a differential sensitivity of AOB and AOA to PTIO and allylthiourea ( ATU ). Similar to the investigated AOA strains, bulk water column nitrification at coastal and open ocean sites with sub‐micromolar ammonia/ammonium concentrations was inhibited by PTIO and insensitive to ATU . These experiments support predictions from kinetic, molecular and biogeochemical studies, indicating that marine nitrification at low ammonia/ammonium concentrations is largely driven by archaea and suggest an important role of NO in the archaeal metabolism.