Oxygen and nitrogen production by an ammonia-oxidizing archaeon

• Published in: Science (American Association for the Advancement of Science) 2022-01, Vol.375 (6576), p.97-100
• Main Authors: Kraft, Beate, Jehmlich, Nico, Larsen, Morten, Bristow, Laura A, Könneke, Martin, Thamdrup, Bo, Canfield, Donald E
• Format: Article
• Language: English
• Subjects: Ammonia; Ammonia - metabolism; Ammonium Compounds - metabolism; Anoxic conditions; Archaea; Archaea - metabolism; Darkness; Depletion; Disproportionation; Energy metabolism; Geologic Sediments - microbiology; Inhalants; Intermediates; Marine environment; Metabolic Networks and Pathways; Metabolism; Microorganisms; Nitric oxide; Nitric Oxide - metabolism; Nitrites; Nitrites - metabolism; Nitrogen; Nitrogen - metabolism; Nitrogen cycle; Nitrous oxide; Nitrous Oxide - metabolism; Nutrient cycles; Nutrients; Oceans; Oxidation; Oxidation-Reduction; Oxygen; Oxygen - metabolism; Oxygen depletion
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.abe6733

Ammonia-oxidizing archaea (AOA) are one of the most abundant groups of microbes in the world’s oceans and are key players in the nitrogen cycle. Their energy metabolism—the oxidation of ammonia to nitrite—requires oxygen. Nevertheless, AOA are abundant in environments where oxygen is undetectable. By carrying out incubations for which oxygen concentrations were resolved to the nanomolar range, we show that after oxygen depletion, produces dinitrogen and oxygen, which is used for ammonia oxidation. The pathway is not completely resolved but likely has nitric oxide and nitrous oxide as key intermediates. joins a handful of organisms known to produce oxygen in the dark. On the basis of this ability, we reevaluate the role of in oxygen-depleted marine environments.