Wintertime Greenhouse Gas Fluxes in Hemiboreal Drained Peatlands

Atmosphere

Mart Muhel¹  Gert Veber¹  Ülo Mander¹  Jaak Jaagus¹  Ain Kull¹  Martin Maddison¹  Birgit Viru¹  Mikk Espenberg¹  Alar Teemusk¹ 

[1] Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuine St. 46, 51014 Tartu, Estonia;

关键词: carbon dioxide;    drained forests;    methane;    nitrous oxide;    peat extraction areas;    peatlands;   

DOI  :  10.3390/atmos11070731

来源: DOAJ

【 摘 要 】

The aim of this study is to estimate wintertime emissions of greenhouse gases CO₂, N₂O and CH₄ in two abandoned peat extraction areas (APEA), Ess-soo and Laiuse, and in two Oxalis site-type drained peatland forests (DPF) on nitrogen-rich sapric histosol, a Norway spruce and a Downy birch forest, located in eastern Estonia. According to the long-term study using a closed chamber method, the APEAs emitted less CO₂ and N₂O, and more CH₄ than the DPFs. Across the study sites, CO₂ flux correlated positively with soil, ground and air temperatures. Continuous snow depth > 5 cm did not influence CO₂, but at no snow or a thin snow layer the fluxes varied on a large scale (from −1.1 to 106 mg C m⁻² h⁻¹). In all sites, the highest N₂O fluxes were observed at a water table depth of −30 to −40 cm. CH₄ was consumed in the DPFs and was always emitted from the APEAs, whereas the highest flux appeared at a water table >20 cm above the surface. Considering the global warming potential (GWP) of the greenhouse gas emissions from the DPFs in the wintertime, the flux of N₂O was the main component of warming, showing 3–6 times higher radiative forcing values than that of CO₂ flux, while the role of CH₄ was unimportant. In the APEAs, CO₂ and CH₄ made up almost equal parts, whereas the impact of N₂O on GWP was minor.

【 授权许可】

Unknown