Comparing carbon in sediment of primary and artificially generated mangrove forests

Soil from primary/natural and artificially generated mangrove forests from Lamongan, Indonesia, was analyzed for bulk density, carbon content and nitrogen content. Samplings were carried out at a total of 12 stations and up to 1 m depth (0-10, 10-25, 25-40, 40-70 and 70-100 cm). Organic matter contents were analyzed using loss-on-ignition and values were converted to organic carbon content using an accepted conversion factor of 0.58. The results showed that the primary forest had lower bulk density and higher carbon and nitrogen contents than those of the artificial forest. On average, the bulk densities of natural and artificial forests were 0.73 g cm-3 and 0.96 g cm^-3 respectively, while carbon contents were 6.39% and 3.67% respectively. Carbon and nitrogen stocks of the primary forest were 477.82±70.75 MgC ha^-1 and 38.91±22.84 MgN ha^-1respectively while they were lower at the artificial forest (363.54±52.66 MgC ha^-1 and 11.75±2.54 MgN ha^-1 respectively). Higher carbon content on the natural forest significantly contributes to higher amount of carbon stocks in the forest. Carbon/nitrogen ratios were 21 and 31 for primary and artificial mangrove forests respectively. Marine based carbon pools might also play a role in the primary mangrove forest as it had lower carbon/nitrogen ratios.