Distribution Pattern and Influencing Factors for Soil Organic Carbon (SOC) in Mangrove Communities at Dongzhaigang, China

Mangrove wetlands constitute an important carbon pool and play an important role in the global carbon balance. Understanding the distribution and influencing factors for soil organic carbon (SOC) in different mangrove communities can improve the estimation of carbon sink capacity. The SOC content and physicochemical properties were investigated from six mangrove communities dominated by Avicennia marina, Aegiceras corniculatum, Bruguiera sexangula, Sonneratia apetala, Rhizophora stylosa, or Ceriops tagal in Dongzhaigang, Southern China. The SOC content ranged from 2.60 to 89.51 g kg^-1 with a mean of 18.35 g kg^-1. The SOC content and density decreased with the depth from surface to bottom and with the tidal gradient from the low intertidal zone to the high intertidal zone except for the SOC density in the soils of the three arbor communities (S. apetala, R. stylosa, and B. sexangula). The SOC content was more related to soil nutrient elements such as total nitrogen, total phosphorus, and total potassium than to pH, bulk density, conductivity, and other soil environmental factors. Among these six mangrove plants, R. stylosa and A. corniculatum should be highly prioritized during mangrove restoration for the higher soil carbon sequestration rate and the stronger adaptive capacity.