CCA ordination among the species, sampling stations and environmental variables was built based on fourth root transformed abundances and log(x+1) transformed fitted-environmental variables that selected from conditional inference tree analysis. The length of the arrow is adjusted to 2.76times for the physical size of the plot. Environmental variables code: SS, Sedimentary sulfide; SOC, Sedimentary organic carbon; STP, Sedimentary total phosphorus; DO, Dissolved oxygen; CO, Water colour; RP, Reactive phosphorus.