Extending the SUSI peatland simulator to include dissolved organic carbon formation, transport and biodegradation - Proper water management reduces lateral carbon fluxes and improves carbon balance

Marjo Palviainen; Jukka Pumpanen; Virginia Mosquera; Eliza Maher Hasselquist; Hjalmar Laudon; Ivika Ostonen; Ain Kull; Florence Renou Wilson; Elina Peltomaa; Mari Könönen; Samuli Launiainen; Heli Peltola; Anne Ojala; Annamari Laurén

doi:10.1016/j.scitotenv.2024.175173

Extending the SUSI peatland simulator to include dissolved organic carbon formation, transport and biodegradation - Proper water management reduces lateral carbon fluxes and improves carbon balance

Sci Total Environ. 2024 Nov 10:950:175173. doi: 10.1016/j.scitotenv.2024.175173. Epub 2024 Aug 6.

Authors

Affiliations

¹ Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014, Finland. Electronic address: marjo.palviainen@helsinki.fi.
² Department of Environmental and Biological Sciences, Faculty of Science, Forestry and Technology, University of Eastern Finland, Kuopio, Finland.
³ Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
⁴ Institute of Ecology and Earth Sciences, University of Tartu, Estonia.
⁵ School of Biology and Environmental Science, University College Dublin, Dublin, Ireland.
⁶ Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014, Finland.
⁷ Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland.
⁸ School of Forest Sciences, Faculty of Science, Forestry and Technology, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland.
⁹ Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014, Finland; School of Forest Sciences, Faculty of Science, Forestry and Technology, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland.

PMID: 39117189
DOI: 10.1016/j.scitotenv.2024.175173

Abstract

Drainage intensity and forest management in peatlands affect carbon dioxide (CO₂) emissions to the atmosphere and export of dissolved organic carbon (DOC) to water courses. The peatland carbon (C) balance results from a complex network of ecosystem processes from where lateral C fluxes have typically been ignored. Here, we present a new version of the SUSI Peatland simulator, the first advanced process-based ecosystem model that compiles a full C balance in drained forested peatland including DOC formation, transport and biodegradation. SUSI considers site, stand and terrain characteristics as well as the interactions and feedbacks between ecosystem processes and offers novel ways to evaluate and mitigate adverse environmental impacts with thorough management planning. Here, we extended SUSI by designing and parameterizing a mass-balance based decomposition module (ESOM) based on literature findings and tested the ESOM performance against an independent dataset measured in the laboratory using peat columns collected from Finland, Estonia, Sweden and Ireland. ESOM predicted the CO₂ emissions and changes in DOC concentrations with a reasonable accuracy for the peat columns. We applied the new SUSI for drained peatland sites and found that reducing the depth to which ditches are cleaned by 0.3 m decreased the annual DOC export by 34 (17 %), 29 (19 %) and 7 (5 %) kg ha^-1 in Finland, Estonia and Sweden, respectively, using typical ditch spacing for these countries. Correspondingly, site annual C sink increased by 305, 409 and 32 kg ha^-1 in Finland, Estonia and Sweden, respectively. Our results also indicated that terrain slope can markedly alter the water residence time and consequently DOC biodegradation and export to ditches. We conclude that DOC export can be decreased and site C sink increased by reducing the depth to which ditches are cleaned or by increasing the ditch spacing.

Keywords: Decomposition; Dissolved organic carbon; Ditching; Drainage; Ecosystem modeling; Forest management.

MeSH terms

Biodegradation, Environmental*
Carbon Cycle*
Carbon Dioxide / analysis
Carbon* / analysis
Ecosystem
Environmental Monitoring
Finland
Models, Theoretical
Soil / chemistry
Sweden
Wetlands

Substances

Carbon
Soil
Carbon Dioxide