Community structure of bacteria associated with drifting Chinese plastic debris along with Sargassum golden tides

Abstract

The plastisphere in marine environment can facilitate microbial dispersal and affect all aquatic ecosystems, it has intensified interest in the microbial ecology at this novel substrate in the marine environment. We investigated the bacterial community associated with plastic debris that drifted along with Sargassum golden tides from China to South Korea. Twenty-one plastic debris were collected along the Oegi beach in Jaeun Island and the ambient seawater and Sargassum were also collected in January 2021. The bacterial community of each sample was analyzed using 16S rDNA metabarcoding. We identified 23 bacterial phyla, 47 classes, 111 orders, 257 families, and 744 genera associated with the debris, seawater and Sargassum. Of these, the abundant bacterial associates having >1% relative abundance were 6 phyla, 12 classes, 20 orders, 29 families, and 47 genera. Twenty-one plastic debris, seawater and Sargassum were clustered into 6 groups with 50 % similarity based on the Bray-curtis dissimilarity of bacterial community. The indicator species analysis selected the bacterial representatives for each group: Group 1 was characterized by Flavobacterium; group 2 by Lacinutrix, Polaribacter, Sulfitobacter, Cobetia, and Psychrobacter; group 3 by Actinomarinicola, Ilumatobacter, Lishizhenia, Mesonia, Aliishimia, Amylibacter, Luminiphilus, and Azotobacter; group 4 by Pseudomonas; group 5 by Dokdonia, Ahrensia, Litoreibacter, Shimia, Sulfitobacter, Thalassobius, Nannocystis, Aestuariicella, and Ketobacter; group 6 by Colwellia, Psychromonas, Pseudoarcobacter, and unidentified taxon. The bacterial communities were not related to the type of plastic debris and also differed in the seawater and sargassum. In addition, there was no relationship of bacterial communities between plastic debris type. It is uncertain either the bacteria associated with plastic debris was originated from China or not.