Microbial ecology in a future climate: effects of temperature and moisture on microbial communities of two boreal fens

Abstract

Impacts of warming with open-top chambers on microbial communities in wet conditions and in conditions resulting from moderate water-level drawdown (WLD) were studied across 0-50 cm depth in northern and southern boreal sedge fens. Warming alone decreased microbial biomass especially in the northern fen. Impact of warming on microbial PLFA and fungal ITS composition was more obvious in the northern fen and linked to moisture regime and sample depth. Fungal-specific PLFA increased in the surface peat in the drier regime and decreased in layers below 10 cm in the wet regime after warming. OTUs representing Tomentella and Lactarius were observed in drier regime and Mortierella in wet regime after warming in the northern fen. The ectomycorrhizal fungi responded only to WLD. Interestingly, warming together with WLD decreased archaeal 16S rRNA copy numbers in general, and fungal ITS copy numbers in the northern fen. Expectedly, many results indicated that microbial response on warming may be linked to the moisture regime. Results indicated that microbial community in the northern fen representing Arctic soils would be more sensitive to environmental changes. The response to future climate change clearly may vary even within a habitat type, exemplified here by boreal sedge fen.

The Impact of Experimental Temperature and Water Level Manipulation on Carbon Dioxide Release in a Poor Fen in Northern Poland

“…The differences of peat Q10 values between treatments support previous findings that temperature and moisture have a direct influence on Sphagnum productivity (Turetsky et al 2012) and microbial communities (Peltoniemi et al 2015), and this is reflected in R ECO . The higher temperatures elevate CO 2 respiration and may also stimulate plant productivity, especially in cold regions (Rustad et al 2001).…”

Responses of phenology and biomass production of boreal fens to climate warming under different water‐table level regimes

“…The lower BGBP and shoot versus root allocation in the wet areas of the northern fen probably reflect the slightly wetter conditions with a more steady input of relatively nutrient‐rich water than in the southern fen. Generally, the differences in the response patterns of both plant and microbial (Peltoniemi et al., , ) communities in our two boreal fens suggest that no generalizations should be made based on a small number of sites. This makes research on climate change responses quite challenging, since work on multiple sites during multiple years is required.…”

“…The sites and the experimental setup (Figure ) that followed a split‐plot design have been described in detail by Peltoniemi et al. (, ). There were two WL regimes (whole plots; not replicated within sites): (1) wet (ambient) and (2) water‐level drawdown (WLD) induced by digging a shallow ditch around the WLD plots.…”

Mobility and transport of mercury and methylmercury in peat as a function of changes in water table regime and plant functional groups

“…Bogs, wherein water table position and peat accumulation capacity are governed strongly by the balance between precipitation and evapotranspiration, are particularly vulnerable to climate change [ Winter , ]. Climate‐induced changes in the hydrological regimes of peatlands significantly influence microbial community structure, which may have profound effects on peat decomposition and carbon sequestration [ Nunes et al ., ; Peltoniemi et al ., ]. Changes in bacterial community structure also have important links to methylmercury production in peatlands [ Strickman et al ., ].…”