Spatial and temporal trends in total organic carbon (TOC), black carbon (BC), and total nitrogen (TN) and their relationships under different planting patterns in a restored coastal mangrove wetland: case study in Fujian, China

ABSTRACTThis study aims to determine the sediment changes and the trends in TOC, BC and TN before and after restoration of the mangrove wetland in the Jinjiang Estuary and to determine the effect of the wetland restoration process on the biogeochemical cycle of carbon and nitrogen. The results suggest that the sediments were mainly silt-sized. Among different sites with different types of plants and vegetation densities, the adsorptive ability of N in the plots in plantations of Kandelia obovata, Avicennia marina and Acanthus ilicifolius was the highest. The TOC content differed (p < 0.05) with the density of the plot and significantly differed (p < 0.01) with the mangrove species at the densities of 0.5 × 1 m and 0.5 × 0.5 m. There was a positive relationship between the TOC and TN and the TOC and carbon-nitrogen ratio (C/N) (P < 0.05).