Geophysical characteristics of kuan kreng peat swamp forest at thale noi area

Peatlands, as an important carbon sink, store a large amount of atmospheric carbon. However, peatlands are vulnerable to environmental alteration due to anthropogenic and natural processes. While peatlands are degraded, carbon dioxide emissions arise. The Kuan Kreng peat swamp forest is the second largest peatland in Thailand and is in coastal wetland serving for carbon stock in the subsurface. To assess carbon stock in peatland, the thickness and distribution of the peat layer are necessary. This study determines physical and chemical characteristics of the peatlands in the coastal wetland, southern Thailand by conventional core study and geophysical surveys, including ground penetrating radar (GPR) and electrical resistivity imaging (ERI). There is a significant relationship between chemical and physical properties from the peat layer, which is useful to approximately predict the physical properties and peat layers in the geophysical profiles. The resistivity profiles exhibit a high resistivity response, between 10.99 and 158.94 ohm-m, with an average of 52.52±15.10 ohm-m, interpreted as the peat layers in the shallow subsurface. The high resolution GPR profiles provide an average GPR velocity in peat of 0.040 m/ns and a relative dielectric constant of 54.9 for the peat layers. The peat layer is characterized by a high amplitude of reflection in the GPR profiles. The thickness of the peat layers was estimated from the geophysical surveys and the drilling cores having an average thickness of 0.22±0.04 cm. Average values of bulk density (0.19±0.03 g/cm­3) and TOC (31.18±4.13 wt. %) from the drilling core samples are used to calculate the carbon density in the peat layers giving a result of 59.24±17.20 Kg C/m3. Hence, the carbon stock in study area two is estimated to be at least 823.02±238.96 tons carbon, which accounts for 3,020.49±877.00 tons carbon dioxide. Therefore, considering the entire area of the Kuan Kreng peat swamp forest with the assumption of consistent thickness and distribution of the peat layer, the carbon stock is estimated at a minimum of 9.69±0.35 Mt.