title: Sulphur-cycling bacteria and ciliated protozoans in a Beggiatoaceae mat covering organically enriched sediments beneath a salmon farm in a southern Chilean fjord.
abstract: The colourless mat covering organically enriched sediments underlying an intensive salmon farm in Estero Pichicolo, southern Chile, was surveyed by combined 454 PyroTag and conventional Sanger sequencing of 16S/18S ribosomal RNA genes for Bacteria and Eukarya. The mat was dominated by the sulphide-oxidizing bacteria (SOB) Candidatus Isobeggiatoa, 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, however, ciliated protozoans were highly abundant in microscopy observations, and were represented by the genera Condylostoma, Loxophyllum and Peritromus. Finally, the abundant Sulfurimonas/Sulfurovum also suggest the occurrence of zero-valence sulphur oxidation, probably derived from Beggiatoaceae as a result of bacteriovorus infaunal activity or generated as free S(0) by the Arcobacter bacteria. The survey suggests an intense and complex sulphur cycle within the surface of salmon-farm impacted sediments.
authors.affiliation: Centro i∼mar, Universidad de Los Lagos, Camino a Chinquihue Km. 6, Puerto Montt, Chile. Electronic address: caranda@ulagos.cl.
authors.forename: Carlos P
authors.initials: CP
authors.lastname: Aranda
authors.affiliation: Centro i∼mar, Universidad de Los Lagos, Camino a Chinquihue Km. 6, Puerto Montt, Chile.
authors.forename: Cristian
authors.initials: C
authors.lastname: Valenzuela
authors.affiliation: Centro i∼mar, Universidad de Los Lagos, Camino a Chinquihue Km. 6, Puerto Montt, Chile.
authors.forename: Yessica
authors.initials: Y
authors.lastname: Matamala
authors.affiliation: Centro i∼mar, Universidad de Los Lagos, Camino a Chinquihue Km. 6, Puerto Montt, Chile.
authors.forename: Félix A
authors.initials: FA
authors.lastname: Godoy
authors.affiliation: Centro i∼mar, Universidad de Los Lagos, Camino a Chinquihue Km. 6, Puerto Montt, Chile.
authors.forename: Nicol
authors.initials: N
authors.lastname: Aranda
mesh_terms: D000818:Animals; D017756:Aquaculture; D001419:Bacteria / Q000235:genetics; D002677:Chile; D016798:Ciliophora / Q000235:genetics / Q000378:metabolism; D020564:Deltaproteobacteria / Q000235:genetics / Q000378:metabolism; D063366:Estuaries; D019015:Geologic Sediments / Q000382:microbiology*; D059013:Microbial Consortia; D010084:Oxidation-Reduction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012337:RNA, Ribosomal, 18S; D012474:Salmon; D013455:Sulfur / Q000378:metabolism*
chemical_list: D012336:RNA, Ribosomal, 16S; D012337:RNA, Ribosomal, 18S; D013455:Sulfur
keywords: Aquaculture impact; Arcobacter; Beggiatoa; Condylostoma; Salmon farm; Sulphur cycle