Photogrammetry reveals the depth distribution of scleractinian corals in turbid waters

Depth distribution is an important trait for scleractinian corals, reflecting their adaptability and vulnerability. However, it remains to be quantified and analyzed adequately in turbid coral communities. Here, we used underwater photogrammetry to explore the depth distribution of turbid coral communities in China's Greater Bay Area (GBA). Surveys at the five sites revealed that the depth distribution of GBA coral communities ranged from - 0.91 m to -5.70 m, with an average depth of -3.41 m. The depth distribution of coral communities at different sites varied significantly, showing an increasing trend from inside to outside of Dapeng Bay. Coral cover and generic richness generally showed a unimodal pattern with increasing depth, with peaks in the depth range of -2 to -4 m. Coral genera exhibited significant differences in their distribution depths, and there were variations in generic composition across different depth ranges, suggesting that GBA coral communities exhibited zonation despite their limited depth ranges.