Do microplastics dramatically shape the homogeneity of protozoan colonization in marine environments?

The impacts of microplastics (MPs) on the marine ecosystem have remained the focus of global attention. The microbial colonization plays an important role in driving the functional process of entire marine ecosystems, during which protozoa employ primary contributors for transferring the energy flow from the low to high trophic levels. To investigate the effects of MPs on microbial colonization, the protozoan assemblages were used as test organisms and exposed to a gradient of MP concentrations. With the increase of MP stress, the homogeneity of the test organisms was significantly altered: (1) the α- and γ-diversity indices decreased; (2) both univariate β-diversity and multivariate dispersions in species composition with weighted relative abundance increased; and (3) the traditional β-diversity showed a close linear relationship with multivariate dispersions in both the species composition and weighted relative abundance. Therefore, the results suggest that microplastics may dramatically impact the homogeneity of protozoan colonization in marine ecosystems.