Blue carbon stock in sediments of mangroves and seagrass ecosystems at Southeast Sulawesi, Indonesia

Abstract

AbstractCoastal ecosystems store approximately 80% of carbon in sediments, which could be emitted due to degradation and deforestation. Therefore, protecting and managing these ecosystems are crucial for climate change mitigation. This study aims to determine sediment bulk density (SBD), sediment organic carbon (SOC) concentration, and sediment carbon stocks (SCS) in mangroves and seagrasses, and to elucidate how the protection scheme impacts them. We collected four sediment cores of 100 cm each from protected and unprotected mangrove areas and three sediment cores of 80 cm each from unprotected and protected seagrass areas. The average SBD in mangroves was 0.48 g cm−3 in protected areas and 0.55 g cm−3 in unprotected areas, while the average SBD in seagrass was 0.79 g cm−3 in protected areas and 0.85 g cm−3 in unprotected areas. The average SOC in mangroves was 8.65% in protected areas and 8.63% in unprotected areas, while the average SOC in seagrass was 5.89% and 6.25% in protected and unprotected areas, respectively. The average SCS in the protected area was 381 and 363 Mg C ha−1 in the mangrove and seagrass ecosystems, respectively. On the other hand, the average SCS in the unprotected areas was 449 and 422 Mg C ha−1 in mangroves and seagrass ecosystems, respectively. Although we did not find any significant differences in SCS between protected and unprotected ecosystems regardless of ecosystem types, the conservation management of blue carbon ecosystems is still needed to avoid future carbon emissions.