Contribution of ammonia-oxidizing microorganisms to nitrification potential and N2O production
This study utilized reverse transcription quantitative real-time PCR to investigate the spatial distribution of amoA gene expression levels among ammonia-oxidizing microorganisms in the surface sediments of the East China Sea during spring.Cultivation experiments were performed to assess the relative contributions of ammonia-oxidizing bacteria(AOB)and ammonia-oxidizing archaea(AOA)to the nitrification potential and N2O production in the surface sediments.The results revealed that the expression level of AOA amoA gene was significantly higher than that of AOB(AOA:4.49× 102～2.17×106copies/g;AOB:6.60×101～7.65×105copies/g),with both showing a spatial distribution pattern of lower levels in nearshore areas(AOA:8.92×105copies/g;AOB:2.06×103copies/g)and higher in offshore areas(AOA:1.05×106copies/g;AOB:4.06×104copies/g).Nitrification potential was found to be higher in nearshore sediments than in offshore sediments,with the nitrification process gradually shifting from AOA dominance in nearshore areas to AOB dominance in offshore areas.In the N2O production process,the addition of NH4+significantly enhanced N2O production,with AOB playing a more critical role than AOA in this process.
East China Seasedimentammonia-oxidizing microorganismspotential nitrification rateN2O
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