The study goal was to assess Bacteria and Eukarya community composition in a Beggiatoaceae- dominated mat covering organically enriched sediments underlying a intensive salmon farm
by using 454 as a massive parallel high-throughput sequencing technique of 16S/18S ribosomal RNA genes. More...
The study goal was to assess Bacteria and Eukarya community composition in a Beggiatoaceae- dominated mat covering organically enriched sediments underlying a intensive salmon farm
by using 454 as a massive parallel high-throughput sequencing technique of 16S/18S ribosomal RNA genes. We compare annotations occurring in both mat-forming bacterial biomass collected directly and after cleaning in order to determine if the accompanying bacteria are attached to the mat-forming cells, or are just inhabiting the mat or the top most layer of the sediment. The mat was dominated by the sulphidic-oxidizing bacteria (SOB) Candidatus Issobeggiatoa, Candidatus Parabeggiatoa and Arcobacter. By order of their abundances, sulphate-reducing bacteria (SRB) were represented by diverse deltaproteobacterial Desulfobacteraceae, but also within Desulfobulbaceae, Desulfuromonadaceae and Desulfovibrionaceae. The eukaryotic PyroTags were dominated by polychaetes, copepods and nematodes, nevertheless, ciliated protozoans, highly abundant in microscopy observations, were also represented by the genera Condylostoma, Loxophyllum and Peritromus. Finally, the abundant Sulfurimonas/Sulfurovum also suggests the occurrence of zero-valence sulphur oxidation, probably available from Beggiatoaceae as a result of bacteriovorus infaunal activity or generated as free S° by the Arcobacter bacteria. The survey suggests an intense and complex sulphur cycle within the surface of salmon-farm impacted sediments. Less...