Role of iron oxides in stabilization of soil organic carbon along vegetation distribution gradient in coastal wetland, Southeastern China.

(<15%). Vertically, Fe-OC enrichment was most pronounced in the 10-30 cm soil layer. Model analysis further confirmed that mineral-associated organic carbon (MAOC), belowground biomass (BGB), specific surface area (SSA), silt content, Fe_p, Fe_d, and the Fe(III)/Fe(II) ratio were the core positive predictors driving the spatial heterogeneity of Fe-OC. This study highlights that the coupling of vegetation characteristics, nutrient availability, and iron-mineral protection mechanisms regulates the formation of the coastal "rusty sink", thereby providing a crucial scientific basis for enhancing blue carbon stability under climate change.