CH4 transport in wetland plants under controlled environmental conditions – separating the impacts of phenology from environmental variables

• Main Authors: Ge, Mengyu, Korrensalo, Aino, Putkinen, Anuliina, Laiho, Raija, Kohl, Lukas, Pihlatie, Mari, Lohila, Annalea, Mäkiranta, Päivi, Siljanen, Henri, Tuittila, Eeva Stiina, Wang, Jinsong, Koskinen, Markku
• Other Authors: Department of Agricultural Sciences, Institute for Atmospheric and Earth System Research (INAR), Department of Microbiology, Environmental Soil Science, Helsinki Institute of Sustainability Science (HELSUS), Department of Forest Sciences, Methane and nitrous oxide exchange of forests, Viikki Plant Science Centre (ViPS), Ecosystem processes (INAR Faculty of Agriculture and Forestry)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media Deutschland GmbH 2024
• Subjects: Controlled environments; Herbs; Microbes; Phenology; Plant-mediated CH fluxes; Shrubs; 11831 Plant biology; Environmental sciences; Betula nana
• Online Access: http://hdl.handle.net/10138/577327

Background and Aims: Methane (CH4) fluxes at peatland plant surfaces are net results of transport of soil-produced CH4 and within-plant CH4 production and consumption, yet factors and processes controlling these fluxes remain unclear. We aimed to assess the effects of seasonality, environmental variables, and CH4 cycling microbes on CH4 fluxes from characteristic fen species. Methods: Four species (Carex rostrata, Menyanthes trifoliata, Betula nana, Salix lapponum) were selected, and their CH4 fluxes determined in climate-controlled environments with three mesocosms per growing season per species. Microbial genes for CH4 cycling were analysed to check the potential for within-plant CH4 production and oxidation. Two extra experiments were conducted: removal of C. rostrata leaves to identify how leaves constrain CH4 transport, and a labelling experiment with S. lapponum to distinguish between plant-produced and soil-produced CH4 in the plant flux. Results: All species showed seasonal variability in CH4 fluxes. Higher porewater CH4 concentration increased fluxes from C. rostrata and M. trifoliata, decreased fluxes from S. lapponum, and did not affect fluxes from B. nana. Air temperature only and negatively affected CH4 flux from C. rostrata. Light level did not impact CH4 fluxes. Both methanogens and methanotrophs were detected in shoots of S. lapponum and M. trifoliata, methanotrophs in B. nana, and neither in C. rostrata. Conclusion: Our study demonstrates that the seasonal phase of the plants regulates the CH4 fluxes they mediate across species. The detection of methanogens and methanotrophs in herbs and shrubs suggests that microbial processes may contribute to their CH4 fluxes. Peer reviewed