Methane

Anaerobic bacteria

Anaerobic exercise

Ecology

Bacteria

Biology

Anammox

Wetland

Denitrification

Botany

Nitrogen

Ammonium

Soil water

Anaerobic oxidation of methane

Physiology

Genetics

Organic chemistry

Environmental chemistry

Environmental science

Nitrite

Denitrifying bacteria

Chemistry

Nitrate

Soil Biology and Biochemistry

Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two recently discovered processes in the nitrogen cycle that are catalysed by anammox bacteria and n-damo bacteria, respectively. Here, the depth-specific distribution and importance of anammox bacteria and n-damo bacteria were studied in an urban wetland, Xixi Wetland, Zhejiang Province (China). Anammox bacteria related to Candidatus Brocadia, Candidatus Kuenenia and Candidatus Anammoxoglobus, and n-damo bacteria related to “Candidatus Methylomirabilis oxyfera” were present in the collected soil samples. The abundance of anammox bacteria (2.6–8.6 × 106 copies g−1 dry soil) in the shallow soils (0–10 cm and 20–30 cm) was higher than that (2.5–9.8 × 105 copies g−1 dry soil) in the deep soils, whereas the abundance of n-damo bacteria (0.6–1.3 × 107 copies g−1 dry soil) in the deep soils (50–60 cm and 90–100 cm) was higher than that (3.4–4.5 × 106 copies g−1 dry soil) in the shallow soils. Anammox activity was detected at all depths, and higher potential rates (12.1–21.4 nmol N2 g−1 dry soil d−1) were observed at depths of 0–10 cm and 20–30 cm compared with the rates (3.5–8.7 nmol N2 g−1 dry soil d−1) measured at depths of 50–60 and 90–100 cm. In contrast, n-damo was mainly occurred at depths of 50–60 cm and 90–100 cm with potential rates of 0.7–5.0 nmol CO2 g−1 dry soil d−1. This study suggested the niche segregation of the anammox bacteria and n-damo bacteria in wetland soils, with anammox bacteria being active primarily in deep soils and n-damo bacteria being active primarily in shallow soils.

Depth-specific distribution and importance of nitrite-dependent anaerobic ammonium and methane-oxidising bacteria in an urban wetland