Microbial metabolic potential of hydrothermal vent chimneys along the Submarine Ring of Fire

Abstract

Hydrothermal vents host a diverse community of microorganisms that utilize chemical gradients from the venting fluid for their metabolisms. The venting fluid can solidify to form chimney structures that these microbes adhere to and colonize. These chimney structures are found throughout many different locations in the worlds oceans. In this study, comparative metagenomic analyses of microbial communities on five chimney structures from around the Pacific Ocean were elucidated focusing on the core taxa and genes that are characteristic for each of these hydrothermal vent chimneys, as well as highlighting differences among the taxa and genes found at each chimney due to parameters such as physical characteristics, chemistry, and activity of the vents. DNA from the chimneys was sequenced, assembled into contigs, annotated for gene function, and binned into metagenome-assembled genomes, or MAGs. Genes used for carbon, oxygen, sulfur, nitrogen, iron, and arsenic metabolism were found at varying abundances at each of the chimneys, largely from either Gammaproteobacteria or Campylobacteria. Many taxa had an overlap of these metabolic genes, indicating that functional redundancy is critical for life at these hydrothermal vents. A high relative abundance of oxygen metabolism genes coupled with low carbon fixation genes could be used as a unique identifier for inactive chimneys. Genes used for DNA repair, chemotaxis, and transposases were found to be at higher abundances at each of these hydrothermal chimneys allowing for enhanced adaptations to the ever-changing chemical and physical conditions encountered. IMPORTANCEThe metabolic byproducts of microorganisms that form and reside in hydrothermal vent chimneys facilitate nutrient cycling in both the hydrothermal vent ecosystem and throughout the worlds oceans. Diverse communities of microbes utilize chemicals in the venting fluid to gain energy and biomass. Here, metagenomic and amplicon sequencing was used to identify metabolism genes to better understand the metabolic potential of chimneys. The combination of genes detected in this study sheds light on hydrothermal vent chimneys community structure and metabolic potential throughout the Pacific Ocean.