The first national scale evaluation of organic carbon stocks and sequestration rates of coastal sediments along the West Sea, South Sea, and East Sea of South Korea.

Blue carbon science requires the estimates of organic carbon stock and sequestration rate; however, holistic data analysis remains limited in South Korea. The present study reports current organic carbon stocks and sequestration rates in the coastal areas of West Sea, South Sea, and East Sea of South Korea, encompassing entire intertidal areas using long-term field survey combined with remote sensing technology. Twenty-one intertidal flats were targeted across seven provinces (Gyeonggi, Chungnam, Jeonbuk, Jeonnam, Gyeongnam, Gyeongbuk, Gangwon). Out of the evaluated environmental parameters, mud content represented a significant factor controlling sedimentary organic carbon stocks across target areas, and was significantly positively correlated to the total organic carbon (p < 0.05). Organic carbon stocks measured in salt marshes (i.e., upper intertidal zone) reflected the high carbon fixation capacity of halophytes through primary production. Sediment textural type was classified using analysis of remotely sensed imagery, and was closely correlated to field-based classification data (p < 0.05). Using field and remote sensing results, we estimated total organic carbon stocks (13,142,149 Mg C) and sequestration rates (71,383 Mg C yr-1) in the tidal flats of South Korea. This study presents the first report on blue carbon potential in the Korean tidal flats, providing baseline information on the carbon dynamics of intertidal sediments in this region and, potentially, elsewhere.