Effect of Drainage on Carbon Biogeochemistry and Microbiological Communities in Western Canadian Boreal Peatlands

Abstract

This study compared the bacterial and archaeal communities between a natural peatland and a peatland affected by water table drawdown along a microtopographic position and depth gradient. Peat physicochemical properties, carbon flux and potential CO2 and CH4 production as well as CH4 oxidation were measured to determine which factors affect microbial composition and diversity. Bacterial and archaeal communities were described by targeting the 16S rRNA gene using pyrosequencing. Physicochemical parameters measured included pH, peat temperature, humification, acetate, formate, sulfate, nitrite and nitrate. The most predominant methanotroph genus was Methylocella and the most predominant methanogen group was Methanomicrobiales Rice Cluster II. Diversity indices show humification and position relative to the water table as significant drivers affecting microbial diversity and richness. The control and drained sites differed significantly regarding the physicochemical influences on microbial relative abundance, however, pH affected methanotroph and methanogen relative abundance at both peatland sites.