The impacts of environmental changes on peatland microbial community structure and function

Abstract

Northern peatlands store approximately 30% of the world’s soil carbon, and are also responsible for contemporary fluxes of the greenhouse gases carbon dioxide (CO2) and methane (CH4), making them important players in the global carbon (C) cycle. These greenhouse gas emissions are mediated by peat-dwelling microbes; however, the environmental factors governing the structures and functions of peat microbial communities are still poorly understood. In order to better understand these dynamics, I examined the effects of two forms of environmental change on peatland microbial communities. Firstly, to gain fundamental knowledge of the drivers of microbial community shift due to natural peatland succession, I examined the effects of long-term peat transplantation from a rich fen to a late-successional poor fen. This allowed me to evaluate the relative effects of solid phase chemistry and substrate (largely determined by the parent material/vegetation) versus aqueous chemistry (influenced more by groundwater or precipitation sources), on peat microbial communities. My results suggest that solid phase chemistry, particularly total nitrogen (TN) and C:N, may be important in determining the makeup of peatland bacterial communities. Secondly, I examined the effects of soil warming simulating projected climate change in a poor and an intermediate fen on peat microbial respiration and CH4 production as the preliminary stage of a multi-year, large-scale field experiment. Soil warming did not lead to any effects on CO2 production or CH4 flux during peat incubation.