Methane Oxidation by Endophytic Bacteria Inhabiting Sphagnum sp. and Some Vascular Plants

Z Stępniewska,A Szafranek-Nakonieczna,D Urban,A Banach,A Górski,W Goraj,A Pytlak,A Kuźniar

doi:10.1007/s13157-017-0984-3

Z Stępniewska, A Szafranek-Nakonieczna + Show 6 more

Open Access

https://doi.org/10.1007/s13157-017-0984-3

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Abstract

Methane emission from wetlands is responsible for about 24% of the total CH4 emissions. The value of emission is a result of the balance between the processes of methane formation (methanogenesis) and sinks (methanotrophy). The methanotrophic activity from well-aerated soil surface layers has been relatively well recognized. On the contrary, the active role of plants in reduction of methane emission is rather not fully known. The association of methanotrophic bacteria with plants of Sphagnum spp., has already been recognized. In our investigations, particular attention was paid to vascular plants from a peatland overgrown by Sphagnum spp. but also Eriophorum vaginatum, Carex nigra, and Vaccinium oxycoccos. The gases emitted from the surface of Moszne peatland were collected using the chamber method from selected sites during growing seasons (spring, summer, autumn). To estimate the contribution of plants in methane emissions from the peatland, in each investigated site gas was sampled from the surface with the native flora cover and after removal thereof. Our results show that the reduction in the CH4 emission was related to the plant composition, vegetation period, and conditions of the plants. It was confirmed that the endophytes under investigation belonged to type I methanotrophs.

Highlights

Methane and carbon dioxide are the main greenhouse gases (IPCC 2013)
In the investigated sites covered by C. nigra, E. vaginatum, and S. magellanicum, the thickness of peat deposition was found to be 350 cm, while in sites dominated by V. oxycoccos it was greater and reached 700 cm
The highest values were found in peat covered by C. nigra and E. vaginatum, which was especially noticeable in spring and summer (Table 1)

Summary

Introduction

Methane and carbon dioxide are the main greenhouse gases (IPCC 2013). At the time of the global warming effect, reduction of the methane concentration in the atmosphere, both from natural and anthropogenic sources, is very important. Wetlands, including peatlands, are considered the largest natural source of methane emissions; they emit 100–231 Tg CH4 into the atmosphere annually, which accounts for 10%–45% of the total emissions of this gas (IPCC 2007). Leszczyńskiego 7, 20-069 Lublin, Poland process being long considered to take place only in the uppermost, well-aerated soil horizons. It was suggested that the increased methane emission is a side effect of plant adaptation to soil anoxia, which includes formation of an internal gas-space ventilation system in stems, roots, and rhizomes aiming to allow oxygen transport to the submerged organs. Aerenchyma acts as gas conduits for O2 It creates a shortcut for CH4 by which it can bypass the aerated soil horizons without being oxidized by methanotrophic bacteria

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