Spatial Heterogeneity ofVibriospp. in Sediments of Chinese Marginal Seas

ABSTRACTVibriospp. 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 aboutVibrioecology in benthic environments. Here, we elucidate the abundance, diversity, and spatial distribution ofVibriospp. 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 thatVibriospp. were most abundant in the SCS (∼9.04 × 105copies/g) compared to the YS (∼1.00 × 105copies/g) and ECS (∼8.86 × 105copies/g).Vibriocommunity compositions derived from Illumina sequencing ofVibrio-specific 16S rRNA genes varied significantly between sampling areas, which was reflected by a strong distance-decay pattern. The spatial distribution ofVibriowas governed by a joint effect of spatial and environmental factors (especially temperature, salinity, and SiO32−), 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. WhereasVibrionaceaeOTU20 andPhotobacterium lipolyticumwere prevalent in the YS,Vibrio gigantisandPhotobacterium piscicola, andP. piscicola,Photobacterium lutimaris, andPhotobacterium alginatilyticumwere prevalent in the ECS and SCS, respectively. Our study demonstrated clear spatial heterogeneity ofVibriospp. in sediments of the Chinese marginal seas, laying a foundation for fully understanding the marineVibrioecology and the ecological roles of the species.IMPORTANCEVibriois 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 ofVibriospp. in sediment is limited. Here, we show higherVibrioabundance in Chinese marginal seas than in other studied sediments. There was a clear spatial differentiation ofVibrioabundance and community composition in different sea areas. The benthicVibriocommunity 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 ofVibrioand its environmental controls, facilitating a more comprehensive understanding of the marineVibrioecology.

Spatiotemporal Dynamics of Free-Living and Particle-Associated Vibrio Communities in the Northern Chinese Marginal Seas

ABSTRACT Vibrio species are associated with human health and play important roles in the carbon cycle. The interest in the Vibrio ecology in marine pelagic environments has increased in recent years, and the correlations between the Vibrio community structure and various environmental factors have been demonstrated. However, the identification of planktonic Vibrio species and their relationship with particulate matter are unclear. Here, we elucidated the spatiotemporal dynamics of Vibrio diversity and in relation to environmental factors in the northern Chinese marginal seas, which feature complex and ever-changing environmental conditions. Vibrio abundance derived from quantitative PCR analysis was higher in summer (∼1.4 × 106 copies liter−1) than in winter (∼1.9 × 105 copies liter−1). Interestingly, the average amount of free-living (on a 0.22-μm-pore-size filter membrane) Vibrio was higher (∼3.89 times) than that of particle-associated Vibrio (on a 3-μm-pore-size filter membrane), making it likely that the preferential lifestyle of the planktonic Vibrio community was free living. Shifts in Vibrio community composition identified by high-throughput amplicon sequencing of the Vibrio-specific 16S rRNA gene were observed at both spatial and temporal scales, which were mainly driven by temperature, dissolved oxygen, ammonium, salinity, nitrite, and phosphate. The most prominent operational taxonomic units in summer were closely related to Vibrio campbellii and Vibrio caribbeanicus and shifted to those affiliated with Vibrio atlanticus in winter. Our study demonstrated abundant and diverse Vibrio populations in the northern Chinese marginal seas, contributing to a better understanding of their potential ecological roles in these ecosystems. IMPORTANCE The dynamics of Vibrio communities have been shown in many marine habitats that are close to land, including estuary or harbor areas. Here, we investigated the spatiotemporal dynamics of Vibrio populations in the northern Chinese marginal seas, spanning a wide spatial scale. We showed that the abundances of the Vibrio population in the present study were higher than those in most previously studied areas and that Vibrio species are more likely to adopt a free-living lifestyle. Moreover, our results expanded upon previous results by showing a clear shift in the dominant Vibrio species from summer to winter, which was mainly attributable to the reduction in the abundance of dominant species in summer. Overall, this work contributes to the understanding of the ecology of the Vibrio communities in the marginal seas.