广西茅尾海红树林生态系统碳库特征及其与沉积环境的耦合机制OA

Mangroves are key coastal blue carbon ecosystems.However,the carbon stock allocation among dif-ferent community types and their sedimentary driving mechanisms in semi-closed,low-energy bays remain unclear.This study focused on the Maowei Sea in Guangxi(the estuary of the Pinglu Canal)to investigate the vegetation biomass and sediment physicochemical properties(0-100 cm)of seven mangrove community types,including,Aegiceras corniculatum,Kandelia obovata,Sonneratia apetala,Avicennia marina and their mixed forests.The results showed that the ecosystem carbon densities in the study area ranged from 139.33 to 342.93 Mg C/hm2,exhibiting significant spatial heterogeneity.The sediment carbon stocks were the domi-nant component,accounting for 77.2％to 87.3％of the total stock,while the contribution of the litter layer was less than 1％.Mixed forest communities(e.g.,Aegiceras corniculatum+K.obovata)demonstrated high-er carbon storage capacities than pure forests,indicating a clear community advantage.Sediments were domi-nated by fine-grained fractions,and organic carbon(SOC)showed significant subsurface enrichment in the 20-50 cm soil layer.Correlation analysis revealed a positive correlation between belowground biomass(BGB)and sediment organic carbon densities,and muddy habitats had stronger carbon enrichment capacity than sandy habitats.This reveals that the coupling mechanism of high biomass community input(especially roots)+physical sequestration in fine-grained muddy habitats is the primary driver maintaining deep soil car-bon stocks in this area.This study provides key baseline data before the opening of the Pinglu Canal.It is hy-pothesized that the enhanced ship-induced waves and hydrodynamic changes caused by canal navigation may affect sediment stability.Therefore,long-term monitoring of blue carbon stability along the channel is recom-mended.