Vacuum-extraction of peatlands disturbs bacterial population and microbial biomass carbon

Knowledge concerning the microbial characteristics of natural and post-vacuum extracted ombrotrophic peatlands, as well as peatlands under restoration is limited. In one experiment, microbial comparisons of paired neighboring natural and post-vacuum peatlands in eastern Québec (Canada) were studied to assess the effects of peat mining on microbial indicators and nitrogen (N) cycling. Microbial counts, microbial biomass carbon (MB-C) and N mineralization were examined over two growing seasons. Also, in a second experiment, bio-indicators of the microbial status (microbial counts, MB-C and the quotient of MB-C to total carbon) of one peatland harboring natural, restored and post-vacuum extracted treatments were assessed sporadically over 6 years. The first experiment revealed that peat mining decreased populations of total bacteria, hemicellulolytic and cellulolytic microorganisms and MB-C, but increased peat ammonium content and N mineralization. The bacterial population was found to be lower in the post-vacuum extracted treatment than in natural treatment (control) and under restoration treatment, whereas the actinomycete population was higher in the post-vacuum extracted and restoration treatments than the natural one. Over the 6-year-time course experiment, the MB-C, total C and their quotient revealed a gradual increase in the peatland under restoration, but they remained similar in the post-vacuum extracted peatland treatment. This supports the concept that the total bacterial population and MB-C may be used as an ecological indicator to monitor major site disturbance using paired natural restored peatland. Published by Elsevier Science B.V.