Diversity of prokaryotes at a shallow submarine vent of Panarea Island (Italy) by high-throughput sequencing

Abstract

To determine microbial community composition and possible key microbial processes in the shallow-sea hydrothermal vent system off Panarea Island (Italy), we examined bacterial and archaeal communities of sediment and fluid samples from a hot vent by 16S rDNA Illumina sequencing technique. Both high abundant (>1% of total sequences), low abundant (from 0.1 to <1%) and rare (< 0.1%) phylogenetic groups were responsible for the distinct prokaryotic communities characterizing the heated sediment and fluid. The bacterial and archaeal communities from sediment were dominated by sequences affiliated with Rhodovulum genus ( Alphaproteobacteria ), including phototrophic ferrous-iron-oxidizing purple bacteria, Thiohalospira and Thiomicrospira ( Gammaproteobacteria ), typically involved in the sulphur cycle, and Methanococcus ( Euryarchaeota ). Fluid communities were dominated by anoxygenic phototrophic members of Chlorobium , followed by Thiomicrospira ( Gammaproteobacteria ), Sulfurimonas , Arcobacter and Sulfurospirillum ( Epsilonproteobacteria ), and Methanosarcina ( Euryarchaeota ). Obtained sequences were affiliated with prokaryotes taking a key part in the carbon, iron and sulphur cycling at the shallow hydrothermal system off Panarea Island. Despite the huge sequencing efforts, a great number of Bacteria and Archaea still remains unaffiliated at genus level, indicating that Black Point vent represents a hotspot of prokaryotic diversity.