|| 要旨トップ | 本企画の概要 |
|日本生態学会第60回全国大会 (2013年3月，静岡) 講演要旨
シンポジウム S08-4 (Lecture in Symposium/Workshop)
In northern regions, spike-like N2O emissions from soils are observed in early spring. During this period, snow melting can cause soil thawing, depending on the presence of a frost layer, i.e., the air temperature and the thickness of snow cover in early winter. Soil freezing is a known factor inducing soil denitrification. Our in-situ snow cover manipulation experiment in Hokkaido, Japan, revealed a large N2O flux and increased N2O concentration with decreasing O2 concentration in the surface soil layer immediately after and before the snow-melting period, respectively. This was observed in a treatment plot with deep soil frost formation by snow cover removal until mid-winter. However, in our two-year (2008–2010) observation at this plot, greater maximum soil frost depth did not always result in larger N2O flux. Therefore, we speculate that snow cover and snowmelt water in early spring play important roles in stimulating N2O production as a heat insulator and gas diffusion barrier, respectively, thus creating warm and anoxic microsites in the frozen surface soil layer.