Fig. 4: Results of principal components analysis of mangrove soil parameters for the four settings.

MAOM_SOC is the percentage of mineral-associated organic matter on the total soil carbon; MAOM_Cg_kg⁻¹ soil is the mineral associated with organic matter in grams of carbon per mass of soil; POM_Cg_kg⁻¹ soil is the particulate organic matter, in grams of carbon per kilogram of soil; N is soil nitrogen content in %; C is soil carbon content in %; C:N is carbon-to-nitrogen ratio of the soil in molar basis; δ¹³C is the stable carbon isotope ratio in ‰; Ac_Al_S is syringic acid-to-syringaldehyde ratio; Ac_Al_V is vanillic acid-to-vanillin ratio; VSC is total lignin in milligrams per grams of soil; VSC_C is the total lignin normalized by total soil carbon; C_MAOM is the carbon content of the mineral-associated organic matter; C_POM is the carbon content of the particulate organic matter; C:V is the ratio cinnamyl to vanillyl, S:V is the ratio syringyl to vanillyl. The color of the ellipse and the symbols represent each setting, such as the brown color and circles represent the delta, the green color and triangles represent the estuary, the blue color and the squares represent the open coast karstic setting, and the yellow color and crosses represent the open coast terrestrial setting. The colored ellipses represent confidence ellipses (95% confidence interval) around the centroid of each group. These ellipses indicate the dispersion of the data points within each group along the principal components. The central tendency points are displayed as small symbols and are positioned at the centroid means of each group projected onto the PCA space.