Eukaryotic rather than prokaryotic microbiomes change over seasons in rewetted fen peatlands

Abstract

In the last decades, rewetting of drained peatlands is on the rise worldwide, to restore their significant carbon sink function. Despite the increasing understanding of peat microbiomes, little is known about the seasonal dynamics and network interactions of the microbial communities in these ecosystems, especially in rewetted fens (groundwater-fed peatlands). Here, we investigated the seasonal dynamics in both prokaryotic and eukaryotic microbiomes in three common fen types in Northern Germany. The eukaryotic microbiomes, including fungi, protists and microbial metazoa, showed significant changes of their community structures across the seasons in contrast to largely unaffected prokaryotic microbiomes. Furthermore, our results proved that the dynamics in eukaryotic microbiomes in the rewetted sites differed between fen types, specifically in terms of saprotrophs, arbuscular mycorrhiza and grazers of bacteria. The co-occurrence networks also exhibited strong seasonal dynamics which differed between rewetted and drained sites, and the correlations involving protists and prokaryotes were the major contributors to these dynamics. Our study provides the insight that microbial eukaryotes mainly define the seasonal dynamics of microbiomes in rewetted fen peatlands. Accordingly, future research should unravel the importance of eukaryotes for biogeochemical processes, especially the under-characterized protists and metazoa, in these poorly understood ecosystems.

The impact of summer drought on peat soil microbiome structure and function-A multi-proxy-comparison

“…S1 ). However, compared with the previous year without drought [ 8 ], these patterns were much stronger in both sites, illustrating that microbiomes are sensitive to (extreme) weather changes in rewetted fens. To gain insights from the functional level, the mRNA transcripts related with stress responses annotated with SEED [ 15 ] were investigated.…”

“…Rewetted fen peatlands are locally novel ecosystems [ 7 ], and microbiomes in these ecosystems are still under-characterized. A previous study showed the seasonal dynamics mainly in eukaryotic microbiomes in three rewetted fens [ 8 ], but it remains unclear if this pattern persists in the year with extreme weather events and if the chosen proxy matters in revealing microbiome dynamics.…”

The Microbial Nitrogen Cycling, Bacterial Community Composition, and Functional Potential in a Natural Grassland Are Stable from Breaking Dormancy to Being Dormant Again

“…Similar results were found in a grassland system where plant diversity had a weak effect on microbial populations at small distances [ 72 ]. Soil prokaryotic microbiomes were stable across seasons in peatland soil [ 73 ] and in the sands of temperate and polar coastal regions [ 74 ]. The functional predictions made regarding the nitrogen cycle genes and overall bacterial community showed no variations across seasons, following May ( Figure 1 b and Figure 7 ).…”

Linking Transcriptional Dynamics of Peat Microbiomes to Methane Fluxes during a Summer Drought in Two Rewetted Fens

“…The edaphic properties including water content and concentrations of dissolved organic matter (DOM), nitrate, nitrite, ammonium, and soluble reactive phosphorus were measured as previously described. , The detected DOM consisted of three groups: (i) biopolymers (BP-S), (ii) humic or humic-like substances including building blocks (HL-S), and (iii) low-molecular-weight substances (LM-S), according to Heinz and Zak . The edaphic properties were measured with samples in April, August, and December 2018.…”