Dynamics of methanotrophic communities in tropical alkaline landfill upland soil

Landfill methanotrophs play an important role in greenhouse gas reduction. To understand the dynamics of methanotroph population, quantitative polymerase chain reaction methods (q-PCR) and terminal-restriction fragment length polymorphism (T-RFLP) analyses were used to explore the methanotrophic communities in tropical alkaline landfill soils at 20 and 40cm depths with different vegetation during a year round study. The q-PCR revealed that the amount of methanotrophs were 1.25×10³ to 1.93×10⁶ pmoA-copy (gdrywtsoil)^-1 and were negatively correlated with accumulated precipitation before sampling. The pmoA-based T-RFLP analyses showed that Methylocaldum related populations were dominant for a long residence time, and Methylocystis related populations were dominant in the deeper sites of milk bush-covered region. Canonical correspondence analysis showed that vegetation, accumulated precipitation, temperature, sampling depth and soil pH could affect the methanotrophic community structures. The pmoA-based T-RFLP analysis used in this study provided good resolution within type I methanotrophs and could easily distinguish between type I and type II methanotrophs.