Controls on bacterial and archaeal community structure and greenhouse gas production in natural, mined, and restored Canadian peatlands

Abstract

Northern peatlands are important global C reservoirs, largely because of their slow rates of microbial C mineralization. Particularly in sites that are heavily influenced by anthropogenic disturbances, there is scant information about microbial ecology and whether or not microbial community structure influences greenhouse gas production. This work characterized communities of bacteria and archaea using terminal restriction fragment length polymorphism (T-RFLP) and sequence analysis of 16S rRNA and functional genes across eight natural, mined, or restored peatlands in two locations in eastern Canada. Correlations were explored among chemical properties of peat, bacterial and archaeal community structure, and carbon dioxide (CO2) and methane (CH4) production rates under oxic and anoxic conditions. Bacteria and archaea similar to those found in other peat soil environments were detected. In contrast to other reports, methanogen diversity was low in our study, with only 2 groups of known or suspected methanogens. Although mining and restoration affected substrate availability and microbial activity, these land-uses did not consistently affect bacterial or archaeal community composition. In fact, larger differences were observed between the two locations and between oxic and anoxic peat samples than between natural, mined, and restored sites, with anoxic samples characterized by less detectable bacterial diversity and stronger dominance by members of the phylum Acidobacteria. There were also no apparent strong linkages between prokaryote community structure and CH4 or CO2 production, suggesting that different organisms exhibit functional redundancy and/or that the same taxa function at very different rates when exposed to different peat substrates. In contrast to other earlier work focusing on fungal communities across similar mined and restored peatlands, bacterial and archaeal communities appeared to be more resistant or resilient to peat substrate changes brought about by these land uses.

Distinct Anaerobic Bacterial Consumers of Cellobiose-Derived Carbon in Boreal Fens with Different CO 2 /CH 4 Production Ratios

“…Acidobacteria are common in anoxic peat and more prominent with lower pH and oligotrophy (4,33,34,(56)(57)(58)(59). Accordingly, they were more prominent in processing cellobiose-C in the oligotrophic peat than in the mesotrophic peat.…”

Impact of Peat Mining and Restoration on Methane Turnover Potential and Methane-Cycling Microorganisms in a Northern Bog

“…While the response of methane-cycling processes, as well as peat respiration driven by changes in the physicochemical properties and substrate chemistry postharvest and during restoration, have been the focus of previous studies (e.g., references 3, 4, and 8), less is known of the responses of the microorganisms mediating these processes. In particular, the microbial biogeochemistry regulating methane emission during Sphagnum-dominated peat restoration has so far received little attention (9)(10)(11).…”

Metabolic potential of fatty acid oxidation and anaerobic respiration by abundant members of Thaumarchaeota and Thermoplasmata in deep anoxic peat

“…The ISME Journal (2015Journal ( ) 9, 2740Journal ( -2744doi:10.1038/ismej.2015published online 22 May 2015 Peatlands represent carbon rich environments shown to sequester approximately one-third of all soil carbon on Earth (Gorham, 1991). Archaea are particularly abundant in peat soils, with Crenarchaea and Thaumarchaeota comprising up to 60% of the microbial community in subsurface peats (Kemnitz et al, 2007;Lin et al, 2012;Basiliko et al, 2013;Hawkins et al, 2014;Lin et al, 2014). Thaumarchaeotal groups 1.1b and 1.1c were recently estimated to account for 76 ± 33% of total archaea in global soil samples (Auguet et al, 2010), suggesting they may have key roles in Earth's biogeochemical cycles.…”