Interactions among fungal community structure, litter decomposition and depth of water table in a cutover peatland

Abstract

Peatlands are important reservoirs of carbon (C) but our understanding of C cycling on cutover peatlands is limited. We investigated the decomposition over 18 months of five types of plant litter (Calluna vulgaris, Eriophorum angustifolium, Eriophorum vaginatum, Picea sitchensis and Sphagnum auriculatum) at a cutover peatland in Scotland, at three water tables. We measured changes in C, nitrogen (N) and phosphorus (P) in the litter and used denaturing gradient gel electrophoresis to investigate changes in fungal community composition. The C content of S. auriculatum litter did not change throughout the incubation period whereas vascular plant litters lost 30-40% of their initial C. There were no differences in C losses between low and medium water tables, but losses were always significantly less at the high water table. Most litters accumulated N and E. angustifolium accumulated significant quantities of P. C, N and P were significant explanatory variables in determining changes in fungal community composition but explained <25% of the variation. Litter type was always a stronger factor than water table in determining either fungal community composition or turnover of C, N and P in litter. The results have implications for the ways restoration programmes and global climate change may impact upon nutrient cycling in cutover peatlands.

Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown

“…Litter type had the greatest impact on active fungal and actinobacterial communities after the first and second years of decomposition (V). The result agrees with earlier findings that litter quality is the main regulator of initial decomposition and fungal community structure (Trinder et al 2008). Different fungal sequences were typical of certain litter types in different years, indicating that the decomposition stage affects communities as well (Table 5).…”

“…So, the C cycle of peatland is dependent on (i) CO 2 fixation and release, (ii) CH 4 production and consumption, and (iii) the in-and outflow of dissolved organic carbon (DOC) (Urban et al 1989, Sallantaus 1992. The release of DOC can be associated with desorption of organic C from the soil, from the decomposition of peat and plant tissues by soil organisms, or through the exudation of organic C from plant roots (Fenner et al 2005, Trinder et al 2008). DOC output is usually higher than input, which results in a net loss from the peatland by the throughflow of water; net losses of 5-9 g C m -2 a -1 have been measured at a peatland in central Finland (Sallantaus 1992, Sallantaus andKaipainen 1996).…”

Dissimilar bacterial and fungal decomposer communities across rich to poor fen peatlands exhibit functional redundancy

“…Therefore, bogs receive all of their nutrients from precipitation and are dominated by poorly decomposable Sphagnum mosses and shrubs (Aerts et al 1999). The quality of plant litter can have a greater effect on decomposition rates (Trinder et al 2008) and microbial activity (Strakova´et al 2011) than a reduction in water table height alone. For example, Sphagnum leachates that are high in phenolic compounds and uronic acids have been shown to have a detrimental effect on microbial activity (Verhoeven and Toth 1995;Ha¨ttenschwiler and Vitousek 2000;Ha´jek et al 2010).…”

Microbial Community Structure and Activity Linked to Contrasting Biogeochemical Gradients in Bog and Fen Environments of the Glacial Lake Agassiz Peatland

“…However, the focus of this research was restricted largely to specific functional guilds of microorganisms, such as methanogens (7,65), methanotrophs (32), fermenters (34), sulfate reducers (60), or microbes involved in nitrogen cycling (76). To date, cultivation-independent studies of peatland microbial diversity have provided only a limited phylogenetic resolution and depth of coverage due to practical limitations of the techniques used, e.g., terminal restriction fragment length polymorphism (T-RFLP) and clone library construction (2,8,15,20,44,55,58,61,73). Studies of fungi, for example, have suffered from the lack of a high-quality curated database for taxonomic assignment (6).…”