What drives putative bacterial pathogens removal within seagrass meadows?

To analyze the mechanism of bacterial pathogen removal in seagrass meadows, we compared bacterial pathogens abundance in trapped particles in different seagrass meadows under different intensities of human activities. We compared the particle deposition rates and abundances of bacterial pathogen in Thalassia hemprichii, Enhalus acoroides stands and adjacent unvegetated patches. The bacterial pathogens abundance was much higher in E. acoroides than in adjacent unvegetated patches, however, the trapped particles under T. hemprichii were lower than in nearby unvegetated areas with the exception of the pristine seagrass meadow. These results indicate that seagrass, at least E. acoroides, can remove bacterial pathogens by trapping particles. What is unknown, nevertheless, is how the trapped bacterial pathogens are removed by T. hemprichii. We put forward that antibacterial chemical compounds release from seagrass was stimulated by stress from human activities for inhibition of bacterial pathogen. This putative mechanism needs to be explored in future studies. •Pathogen abundances in trapped particles among 4 seagrass meadows were determined.•Pathogen in the trapped particles increased with the intensity of human activities.•E. acoroides remove seawater pathogens by trapping the water column particles.•Antibacterial chemical compounds releasing from seagrass may inhibit pathogens.