Floating Sphagnum moss mats as a tool to lower methane emissions in restored peatlands
- 1University of Manchester, Geography, Manchester, United Kingdom of Great Britain – England, Scotland, Wales (jonny.ritson@manchester.ac.uk)
- 2Centre for Ecology & Hydrology, Deiniol Road, Bangor LL57 2UW, UK
In the new demonstrator project, Greenhouse Gas Removals – Peat, we aim to improve the greenhouse gas balance of peatland restoration projects so that net-negative carbon projects can be achieved. To do this, we are trialling a suite of methods including gully blocking, Sphagnum planting, biomass harvesting coupled with biochar production, and methane suppression via gypsum dosing. Through these methods, we hope to increase the input of recalcitrant carbon whilst minimising methane emissions.
We present the results of a survey of 17 peatland pools across four sites in the south Pennines, UK. The pools were created via different restoration methods and have either been colonised naturally by Sphagnum or have been planted with commercially available mixes. Our data show that floating Sphagnum mats create a poorly mixed zone in the restoration pools where temperature and dissolved oxygen levels are elevated, resulting in lower dissolved methane concentrations beneath the Sphagnum mats compared to the rest of the pool. When accounting for higher methane emission rates due to the elevated temperature, our results suggest an overall ~40% lowering of diffusive methane flux in areas colonised by Sphagnum.
Modelling of water quality parameters from the pools suggest methane flux is controlled via different mechanisms in the two areas of the pools. In the clearwater areas, redox potential and nitrogen availability are the dominant controls on methane flux, whereas under Sphagnum, dissolved oxygen concentration was the only significant driver. We interpret this as a switch in relative activity between methanogens and methanotrophs in the two areas. Taken together, our results provide real world evidence of the role of Sphagnum in creating a habitat niche favourable for methanotrophs and thereby lowering methane flux from peatland restoration projects.
In this presentation we will also discuss preliminary findings from the other treatments being trialled at our sites.
How to cite: Ritson, J., Self, R., Evans, C., and Evans, M.: Floating Sphagnum moss mats as a tool to lower methane emissions in restored peatlands, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5553, https://doi.org/10.5194/egusphere-egu23-5553, 2023.
