Researchers from Germany, Portugal, and Canada reporting in Nature Ecology and Evolution outline gut microbial community shifts in two wild seabird species subjected to microplastics in the environment. The team turned to 16S ribosomal RNA sequences to profile the microbiome communities within cloaca and proventriculus organ samples from dozens of Cory's shearwaters (Calonectris borealis) and northern fulmars (Fulmarus glacialis) found in the waters off Portugal and Canada, respectively. Their results suggest that microplastics can alter the microbial species found in the wild bird gut sites tested, as well as the broader diversity at these microbiome sites. "The amount of microplastics in the gut was significantly correlated with gut microbial diversity and composition: microplastics were associated with decreases in commensal microbiota and increases in (zoonotic) pathogens and antibiotic-resistant and plastic-degrading microbes," the authors report. "These results illustrate that environmentally relevant microplastic concentrations and mixtures are associated with changes in gut microbiomes in wild seabirds."