Metagenomes from acidic N2O reduction microcosms Raw sequence reads

Nitrous oxide (N2O) emissions cause stratospheric ozone depletion and global warming. The reduction of N2O to dinitrogen by microorganisms expressing clade I or clade II N2O reductase (NosZ) is the key biological process to mitigate N2O emissions. Microbial N2O reduction occurs at circumneutral pH with negligible activity reported below pH 5.7, and acidic soils are considered N2O emitters. To reconcile existing inconsistencies between field measurements and laboratory studies, soil samples were collected along an elevational gradient from the Luquillo Experimental Forest (LEF) in Puerto Rico. A series of microcosms explored N2O reduction at acidic (pH ~4.5) versus circumneutral (pH ~7.3) pH conditions and monitored the microbial community responses to high versus low N2O concentrations. N2O reduction was observed in all microcosms after a year of incubation. Metagenome analyses indicate that pH selects for distinct N2O reducers and reveal non-denitrifying bacteria responsible for N2O reduction at low pH (<5).