[U-02] Advanced understanding of Quaternary and Anthropocene hydroclimate changes in East Asia

[U02-P09] Surface Peat Accumulation Rates Estimated Using Multiple Radionuclide Analyses in a Plateau Wetland, Eastern Hokkaido, Japan

*Ren Tsuneoka^1,2, Wataru Sakashita³, Reisuke Kondo^1,4, Yusuke Yokoyama^1,2 (1.Atmosphere and Ocean Research Institute, The University of Tokyo, 2.Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 3.Forest and Forest Products Research Institute, 4.Research Faculty of Agriculture, Hokkaido University)

Keywords:Wetland, Carbon accumulation rate, Peat accumulation rate, Lead-210 dating, Cesium-137, Radiocarbon

Peat accumulation rates in wetlands on plateaus, where sediment supply from rivers is minimal, have been rarely documented. However, evaluating the carbon storage potential of peatlands is crucial for understanding the global carbon cycle. In this study, we used multiple isotopes (Lead-210, cesium-137, and radiocarbon (¹⁴C)) to examine surface peat accumulation on a plateau in eastern Hokkaido, Japan. Our findings indicate that the constant rate of supply model, when corrected for the ¹⁴C bomb peak, can provide reliable accumulation rate estimates. The upper 13 cm of the peat layer accumulated over the past 70 years, with mean accumulation rates of 8.1 ± 3.2 mm yr^-1 in the acrotelm and 1.3 ± 0.5 mm yr^-1 in the catotelm. Comparisons with a previous study suggest that peat accumulation rates remained consistent across the study area in the absence of external disturbances. Furthermore, our estimated carbon accumulation rates (CARs) were 110 ± 37 gC m^-2 yr^-1 in the acrotelm and 33 ± 9 gC m^-2 yr^-1 in the catotelm, providing a valuable reference for decadal-scale CAR in the East Asian monsoon region.