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

Abstract

<i>Vibrio</i> species are associated with human health and play important roles in the carbon cycle. The interest in the <i>Vibrio</i> ecology in marine pelagic environments has increased in recent years, and the correlations between the <i>Vibrio</i> community structure and various environmental factors have been demonstrated. However, the identification of planktonic <i>Vibrio</i> species and their relationship with particulate matter are unclear. Here, we elucidated the spatiotemporal dynamics of <i>Vibrio</i> diversity and in relation to environmental factors in the northern Chinese marginal seas, which feature complex and ever-changing environmental conditions. <i>Vibrio</i> 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) <i>Vibrio</i> was higher (∼3.89 times) than that of particle-associated <i>Vibrio</i> (on a 3-μm-pore-size filter membrane), making it likely that the preferential lifestyle of the planktonic <i>Vibrio</i> community was free living. Shifts in <i>Vibrio</i> community composition identified by high-throughput amplicon sequencing of the <i>Vibrio</i>-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 <i>Vibrio campbellii</i> and <i>Vibrio caribbeanicus</i> and shifted to those affiliated with <i>Vibrio atlanticus</i> in winter. Our study demonstrated abundant and diverse <i>Vibrio</i> populations in the northern Chinese marginal seas, contributing to a better understanding of their potential ecological roles in these ecosystems.<b>IMPORTANCE</b> The dynamics of <i>Vibrio</i> 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 <i>Vibrio</i> populations in the northern Chinese marginal seas, spanning a wide spatial scale. We showed that the abundances of the <i>Vibrio</i> population in the present study were higher than those in most previously studied areas and that <i>Vibrio</i> 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 <i>Vibrio</i> 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 <i>Vibrio</i> communities in the marginal seas.