Abstract: “Coastal wetlands are experiencing sea level rise, global warming and vegetation shift due to climate change. Climate change may influence soil organic matter mineralization, which plays an important role as a sink for atmospheric carbon; therefore it is important to identify the impact of hydrological processes on soil organic matter. We investigated how soil organic matter content responds to hydroperiod (i.e., the length of time portion of year during which the wetland area is waterlogged), distance from the river mouth and soil moisture content in subtropical Fukido riverine mangrove on Ishigaki Island. The relationships between soil organic matter with the hydroperiod, moisture and distance from the river mouth were analyzed by performing principle component analysis (PCA) on the log-transformed data set and by simple correlations. The organic matter in the sediments ranged between 5.8 and 23.1 %, with an average of 12.3 ± 3.3 % (SD) and decreased from river side to landward side.”

Keywords: Blue carbon, anoxic soil, inundation, sea level rise, decomposition, mineralization