Establishing community structure and diversity within hydrothermal vent bacterial communities of the East Pacific Rise at 9°50′N

Hydrothermal vents along the East Pacific Rise at 9°50'N support diverse microbial and animal communities driven by chemosynthesis. This study uses microbial growth chambers to investigate microbial colonization dynamics and community structure across multiple venting locations. Microbial growth chambers were deployed and incubated in vent fluids with distinct geochemical conditions for varying durations (2-257 days). Amplicon sequencing of SSU rRNA genes revealed that Campylobacteria, particularly <i>Sulfurimonas</i> and <i>Sulfurovum</i>, dominated across sites, in general, while Zetaproteobacteria were prevalent specifically in iron-rich environments. Community composition shifted over time, with an increased abundance of potential secondary producers and heterotrophs, including Alphaproteobacteria and Bacteroidia. Network analyses indicated dynamic microbial interactions, with community assembly influenced by temperature, sulfide, and iron availability. The findings suggest that microbial colonization at hydrothermal vents is a stochastic process shaped by environmental factors, with a subset of early colonizers persisting in developed communities. These results enhance our understanding of microbial succession in hydrothermal ecosystems and their role in biogeochemical cycling.IMPORTANCEEstablished microbial communities are taxonomically and metabolically diverse, and this impacts their function within an ecosystem. The current study sheds light on patterns of community assembly at hydrothermal vents with varying chemistry in a small geographic range. Complex microbial communities formed rapidly and matured to include more potential heterotrophs at these locations. There were differences between sites, likely due to vent fluid chemistry. However, some taxa were found across all sites, even with these differences in chemistry. While common taxa were found across all sites, no one type was found to be consistently dominant, suggesting that microbial communities at hydrothermal vents may form randomly, depending on which bacteria arrive first and the local environment. However, chemistry still plays a big role in shaping these communities.