Fig. 1

Sampling sites of mangrove soils. a Satellite image of sampling sites in Guangxi and Hainan Provinces, China. Mangrove soil sampling sites are indicated with red stars. b Satellite image of sampling sites in Guangxi Province. c Satellite image of sampling sites in Hainan Province. For panels B and C, sampling sites are marked based on their sampling habitats, i.e., red, yellow and blue dots for bay, river and port, respectively. Refer to the ‘Methods’ section for details