Spatial Heterogeneity of <i>Vibrio</i> spp. in Sediments of Chinese Marginal Seas

Abstract

<i>Vibrio</i> spp. are ubiquitous marine bacteria with high metabolism flexibility and genome plasticity. Previous studies have revealed the dynamics of planktonic vibrios in relation to environmental forces, such as temperature and salinity. However, little is known about <i>Vibrio</i> ecology in benthic environments. Here, we elucidate the abundance, diversity, and spatial distribution of <i>Vibrio</i> spp. in sediments of the Chinese marginal seas, with a wide spatial range from north to south covering the Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS). Quantitative analysis showed that <i>Vibrio</i> spp. were most abundant in the SCS (∼9.04 × 10⁵ copies/g) compared to the YS (∼1.00 × 10⁵ copies/g) and ECS (∼8.86 × 10⁵ copies/g). <i>Vibrio</i> community compositions derived from Illumina sequencing of <i>Vibrio</i>-specific 16S rRNA genes varied significantly between sampling areas, which was reflected by a strong distance-decay pattern. The spatial distribution of <i>Vibrio</i> was governed by a joint effect of spatial and environmental factors (especially temperature, salinity, and SiO₃^2-), and their respective pure effects explained only a small fraction of the community variation. Moreover, we identified the most prominent operational taxonomic units (OTUs) that were partitioned in these sea areas. Whereas <i>Vibrionaceae</i> OTU20 and <i>Photobacterium lipolyticum</i> were prevalent in the YS, <i>Vibrio gigantis</i> and <i>Photobacterium piscicola</i>, and <i>P. piscicola</i>, <i>Photobacterium lutimaris</i>, and <i>Photobacterium alginatilyticum</i> were prevalent in the ECS and SCS, respectively. Our study demonstrated clear spatial heterogeneity of <i>Vibrio</i> spp. in sediments of the Chinese marginal seas, laying a foundation for fully understanding the marine <i>Vibrio</i> ecology and the ecological roles of the species.<b>IMPORTANCE</b><i>Vibrio</i> is an important component of natural marine microbial populations in terms of pathogenicity and roles in carbon cycling. Compared to the marine pelagic environment, our knowledge of the diversity and distribution pattern of <i>Vibrio</i> spp. in sediment is limited. Here, we show higher <i>Vibrio</i> abundance in Chinese marginal seas than in other studied sediments. There was a clear spatial differentiation of <i>Vibrio</i> abundance and community composition in different sea areas. The benthic <i>Vibrio</i> community displayed a strong distance-decay pattern across a wide spatial range, which was formed under the combined effects of spatial and environmental factors. These results provide deep insights into the ecological dynamics of <i>Vibrio</i> and its environmental controls, facilitating a more comprehensive understanding of the marine <i>Vibrio</i> ecology.