Abstract:
Wetland is known as a source of atmospheric methane, typically produced by microbiological and
chemical processes under anaerobic conditions. Soil temperature in the wetlands is a key factor to control the
processes. Peat soils can be found in many types of wetlands. Peat soils contain high organic matter content and
thus shows unique physical properties such as high total porosity and shrinkage. This study aims to study the heat
transport of peat soils at variably saturated conditions and effects of volume shrinkage on thermal properties of
peat soils. Study area of this research is Bibai marsh, Hokkaido in Japan. Undisturbed peat samples were obtained
from two different peat profiles at different depths. In general, the thermal conductivity (TC) and the heat capacity
(HC) of peat soils linearly increased with increasing volumetric water content, and simple two-phase (solid and
water phases) models for TC and HC could generally express TC and HC behaviors, respectively, for most of peat
soils. In addition, the observed volume-shrinkage of the peat soils under dry conditions did not affect the TC and
HC behaviors for the studied samples.
