Recovery of fen peatland microbiomes and predicted functional profiles after rewetting

Abstract

Many of the world’s peatlands have been affected by water table drawdown and subsequent loss of organic matter. Rewetting has been proposed as a measure to restore peatland functioning and to halt carbon loss, but its effectiveness is subject to debate. An important prerequisite for peatland recovery is a return of typical microbial communities, which drive key processes. To evaluate the effect of rewetting, we investigated 13 fen peatland areas across a wide (>1500 km) longitudinal gradient in Europe, in which we compared microbial communities between drained, undrained, and rewetted sites. There was a clear difference in microbial communities between drained and undrained fens, regardless of location. Community recovery upon rewetting was substantial in the majority of sites, and predictive functional profiling suggested a concomitant recovery of biogeochemical peatland functioning. However, communities in rewetted sites were only similar to those of undrained sites when soil organic matter quality (as expressed by cellulose fractions) and quantity were still sufficiently high. We estimate that a minimum organic matter content of ca. 70% is required to enable microbial recovery. We conclude that peatland recovery after rewetting is conditional on the level of drainage-induced degradation: severely altered physicochemical peat properties may preclude complete recovery for decades.

Effects of water level alteration on carbon cycling in peatlands

“…Peat property changes include loss of soil C contents, increased bulk density and vertical hydraulic gradient, reduced porosity, decreased saturated hydraulic conductivity and a greater pore water residence time (Weiss et al 1998;Price 2003;Whittington and Price 2006;Berger et al 2018;Bourgault et al 2018). Meanwhile, these properties may not be regained after the restoration of natural hydrology, even for decades (Schimelpfenig, Cooper, and Chimner 2014;Lazcano et al 2018;Schulte et al 2019;Emsens et al 2020).…”

The Response of Microbial Communities to Peatland Drainage and Rewetting. A Review

“…Drainage of fens has caused a decrease in diversity and species richness of the wider microbial community, and a shift toward Acidobacteria as the dominant bacterial phylum, non-methanogens as the dominant archaea and saprotrophs as the dominant fungal guild (Urbanová and Bárta, 2016;Jassey et al, 2018;Emsens et al, 2020). In fens, members of the phyla Proteobacteria and Bacteroidetes have been shown to be particularly sensitive to drought, as well as protists of the phylum Rhizaria and ectomycorrhizal fungi (Peltoniemi et al, 2012;Potter et al, 2017).…”

The Power of Nature‐Based Solutions: How Peatlands Can Help Us to Achieve Key EU Sustainability Objectives

“…[ 16 ] Recent studies from European fens, the peatland type most dramatically affected by drainage for agriculture, point at quick recovery of key microbial communities and plant functional types. [ 22,23 ]…”