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.