Seafloor Incubation Experiments at Deep-Sea Hydrothermal Vents Reveal Distinct Biogeographic Signatures of Autotrophic Communities

The discharge of hydrothermal vents on the seafloor provides energy sources for dynamic and productive ecosystems, which are supported by chemosynthetic microbial populations. These populations use the energy gained by oxidizing the reduced chemicals contained within the vent fluids to fix carbon dioxide and support multiple trophic levels. Hydrothermal discharge is ephemeral and chemical composition of such fluids varies over space and time, which can result in geographically distinct microbial communities. To investigate the foundational members of the community, microbial growth chambers were placed within the hydrothermal discharge at Axial Seamount (Juan de Fuca Ridge), Magic Mountain Seamount (Explorer Ridge), and Kamaehuakanaloa Seamount (Hawaii hotspot). Campylobacteria were identified within the nascent communities, but different amplicon sequence variants were present at Axial and Kamaehuakanaloa Seamounts, indicating that geography in addition to the composition of the vent effluent influences microbial community development. These results provide insights to nascent microbial community structure and shed light on the development of diverse lithotrophic communities at hydrothermal vents.