title: Ferrous iron- and ammonium-rich diffuse vents support habitat-specific communities in a shallow hydrothermal field off the Basiluzzo Islet (Aeolian Volcanic Archipelago).
abstract: Ammonium- and Fe(II)-rich fluid flows, known from deep-sea hydrothermal systems, have been extensively studied in the last decades and are considered as sites with high microbial diversity and activity. Their shallow-submarine counterparts, despite their easier accessibility, have so far been under-investigated, and as a consequence, much less is known about microbial communities inhabiting these ecosystems. A field of shallow expulsion of hydrothermal fluids has been discovered at depths of 170-400 meters off the base of the Basiluzzo Islet (Aeolian Volcanic Archipelago, Southern Tyrrhenian Sea). This area consists predominantly of both actively diffusing and inactive 1-3 meters-high structures in the form of vertical pinnacles, steeples and mounds covered by a thick orange to brown crust deposits hosting rich benthic fauna. Integrated morphological, mineralogical, and geochemical analyses revealed that, above all, these crusts are formed by ferrihydrite-type Fe3+oxyhydroxides. Two cruises in 2013 allowed us to monitor and sampled this novel ecosystem, certainly interesting in terms of shallow-water iron-rich site. The main objective of this work was to characterize the composition of extant communities of iron microbial mats in relation to the environmental setting and the observed patterns of macrofaunal colonization. We demonstrated that iron-rich deposits contain complex and stratified microbial communities with a high proportion of prokaryotes akin to ammonium- and iron-oxidizing chemoautotrophs, belonging to Thaumarchaeota, Nitrospira, and Zetaproteobacteria. Colonizers of iron-rich mounds, while composed of the common macrobenthic grazers, predators, filter-feeders, and tube-dwellers with no representatives of vent endemic fauna, differed from the surrounding populations. Thus, it is very likely that reduced electron donors (Fe2+and NH4+) are important energy sources in supporting primary production in microbial mats, which form a habitat-specific trophic base of the whole Basiluzzo hydrothermal ecosystem, including macrobenthic fauna.
authors.affiliation: Institute for Marine Sciences, ISMAR-CNR, Bologna, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Bortoluzzi
authors.affiliation: Institute for Environmental Protection and Research, ISPRA, Milazzo, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Romeo
authors.affiliation: Institute for Coastal Marine Environment, IAMC-CNR, Messina, Italy.
authors.forename: V
authors.initials: V
authors.lastname: La Cono
authors.affiliation: Institute for Coastal Marine Environment, IAMC-CNR, Messina, Italy.
authors.forename: G
authors.initials: G
authors.lastname: La Spada
authors.affiliation: Institute for Coastal Marine Environment, IAMC-CNR, Messina, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Smedile
authors.affiliation: Institute for Environmental Protection and Research, ISPRA, Milazzo, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Esposito
authors.affiliation: Department of Physics and Earth Sciences, University of Messina, Messina, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Sabatino
authors.affiliation: National Institute of Geophysics and Volcanology, Palermo, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Di Bella
authors.affiliation: Institute for Environmental Protection and Research, ISPRA, Milazzo, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Canese
authors.affiliation: Institute for Environmental Protection and Research, ISPRA, Milazzo, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Scotti
authors.affiliation: DISTAV, University of Genoa, Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Bo
authors.affiliation: Institute for Coastal Marine Environment, IAMC-CNR, Messina, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Giuliano
authors.affiliation: School of Environment, Natural Resources & Geography, Bangor University, Bangor, UK.
authors.forename: D
authors.initials: D
authors.lastname: Jones
authors.affiliation: School of Biological Sciences, Bangor University, Bangor, UK.|Immanuel Kant Baltic Federal University, Kaliningrad, Russia.
authors.forename: P N
authors.initials: PN
authors.lastname: Golyshin
authors.affiliation: Institute for Coastal Marine Environment, IAMC-CNR, Messina, Italy.|Immanuel Kant Baltic Federal University, Kaliningrad, Russia.
authors.forename: M M
authors.initials: MM
authors.lastname: Yakimov
authors.affiliation: Institute for Environmental Protection and Research, ISPRA, Palermo, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Andaloro
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism*; D001105:Archaea / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D052837:Chemoautotrophic Growth; D017753:Ecosystem; D005296:Ferrous Compounds / Q000378:metabolism*; D060086:Hydrothermal Vents / Q000382:microbiology*; D007501:Iron / Q000378:metabolism*; D008521:Mediterranean Islands; D018707:Volcanic Eruptions
chemical_list: D064751:Ammonium Compounds; D005296:Ferrous Compounds; D007501:Iron
keywords: Aeolian Islands; chemosynthesis; iron(II)-rich hydrothermal vents; microbial community; submarine volcanoes