Impacts of Elevated Atmospheric CO2 and Plant Species Composition on Methane Emissions from Subarctic Wetlands

• Published in: Wetlands
• Main Authors: Bridgman, Matthew J., Lomax, Barry H., Sjögersten, Sofie
• Other Authors: University of Nottingham
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2020
• Subjects: General Environmental Science; Ecology; Environmental Chemistry; Arctic; Eriophorum; Subarctic
• Online Access: http://dx.doi.org/10.1007/s13157-019-01203-5; https://link.springer.com/content/pdf/10.1007/s13157-019-01203-5.pdf; https://link.springer.com/article/10.1007/s13157-019-01203-5/fulltext.html

Abstract Elevated atmospheric CO 2 may create greater methane (CH 4 ) emissions from subarctic wetlands. To date such ecosystem feedbacks remain poorly understood, particularly in relation to how different wetland plant species will control such feedbacks. In this study we exposed plant-peat mesocosms planted with four Cyperaceae species to 400 and 800 ppm atmospheric CO 2 concentrations and measured plant and peat properties as well as CH 4 fluxes. Above ground biomass for plants grown at 800 ppm CO 2 increased for E. angustifolium , Eriophorum vaginatum and Carex brunnescens , but the total biomass of C. acuta decreased relative to the ambient CO 2 treatment. The plant species and elevated CO 2 treatment affected both peat redox potential and pore water chemistry. There was no overall effect of the elevated CO 2 on CH 4 emissions, however, CH 4 emissions were related to above ground biomass and redox potential, both of which were significantly altered by elevated CO 2 . Our study shows that species composition poses an important control on how wetland communities will respond to elevated CO 2 and that plant mediated changes of peat biogeochemical processes, in response to elevated CO 2 levels, may affect CH 4 emissions from sub-arctic wetlands, but any such responses will differ among species.