Low nitrous oxide concentration and spatial microbial community transition across an urban river affected by treated sewage.

Urban rivers receive used water derived from anthropogenic activities and are a crucial source of the potent greenhouse gas nitrous oxide (NO). However, considerable uncertainties still exist regarding the variation and mechanisms of NO production in response to the discharge of treated sewage from municipal wastewater treatment plants (WWTPs). This study investigated NO concentrations and microbial processes responsible for nitrogen conversion upstream and downstream of WWTPs along the Tama River flowing through Tokyo, Japan.

Exploration and enrichment of methane-oxidizing bacteria derived from a rice paddy field emitting highly concentrated methane.

Methane-oxidizing bacteria (MOB) possess the metabolic potential to assimilate the highly potent greenhouse gas, CH, and can also synthesize valuable products. Depending on their distinct and fastidious metabolic pathways, MOB are mainly divided into Type I and Type II; the latter are known as producers of polyhydroxyalkanoate (PHA). Despite the metabolic potential of MOB to synthesize PHA, the ecophysiology of MOB, especially under high CH flux conditions, is yet to be understood.