Diversity of microbial communities at shallow-hydrothermal vents off Dominica, Lesser Antilles

Marchesi, Marco (2014) Diversity of microbial communities at shallow-hydrothermal vents off Dominica, Lesser Antilles. [Laurea magistrale], Università di Bologna, Corso di Studio in Biologia marina [LM-DM270] - Ravenna, Documento ad accesso riservato.
Documenti full-text disponibili:
[img] Documento PDF
Full-text non accessibile

Download (1MB) | Contatta l'autore


Hydrothermal vents are often compared to desert oases, because of the presence of highly diverse and abundant biotic communities inhabiting these extreme environments. Nevertheless, the microbial communities associated with shallow-hydrothermal systems have been poorly studied. Hydrothermal activity at Dominica Island is quite well known under the geological and geochemical aspects, but no previous information existed about the microbial communities associated to this area. This thesis is therefore targeting the microbiology of hydrothermal sediments combining geochemical and molecular biological investigations, focusing on differences between hydrothermal vents and background (i.e. control) areas, and between hydrothermal sites. It was also intended to assess relationship between geochemical parameters and microbial diversity at the two hydrothermally impacted sites. Two shallow-sea hydrothermal vents located south-west off Dominica Island (Lesser Antilles) have been investigated in this study: Champagne Hot Springs and Soufriere Bay offshore vent. During this study, sediments for geochemical and molecular analyses were collected every 2 cm from the two impacted areas and from two control sites not associated with hydrothermal activity; in situ temperatures measurements were also taken every 5 cm deep in the sediment for all the sites. A geochemical characterization of the sediment porewater was performed through the analysis of several elements’ concentrations (i.e. H2S, Cl-, Br-, SO42-, Fe2+, Na+, K+, B+, Si+). Microbial communities at the different sites were studied by Automated Intergenic Spacer Analysis (ARISA). Inspection of the operational taxonomic units (OTUs) distribution was performed, as well as statistical analyses for communities’ structure and composition differences, and for changes of β-diversity along with sediment geochemistry. Data suggested that mixing between hydrothermal fluids and seawater results in distinct different environmental gradients and potential ecological niches between the two investigated hydrothermal vents, reflecting a difference in microbial community structures between them.

Tipologia del documento
Tesi di laurea (Laurea magistrale)
Autore della tesi
Marchesi, Marco
Relatore della tesi
Corso di studio
Ordinamento Cds
Parole chiave
shallow-sea; hydrothermal vents; Dominica; microbial diversity; fluid flow; community structure; ARISA
Data di discussione della Tesi
20 Marzo 2014

Altri metadati

Gestione del documento: Visualizza il documento