Microbial community structure and diversity in the wide and shallow Venice lagoon were assessed, prior to construction of mobile dams, at nine stations representative of four different sub-basins previously selected on the basis of international guidelines for sediment quality. The sediments were mainly anoxic and were colonized by microbial communities the species richness of which was quantitatively correlated with total elemental sulfur and acid-volatile sulfide. Automated ribosomal intergenic spacer analysis clustered the stations into three groups. One station for each group was hence analyzed in detail for bacterial and archaeal diversity by screening of 16S rRNA gene clone libraries. The dominance of Gammaproteobacteria clones (84% with a high proportion of Vibrionaceae, indicator of urban pollution) determined significant divergence of the station adjacent to industrial and metropolitan areas. Bacteroidetes were widespread, especially where prairies of aquatic plants are located. The other two analyzed stations were dominated by bacterial taxa implicated in the sulfur cycle: the anoxygenic photosynthetic Chromatiales, sulfate- and sulfur-reducing Desulfobacterales and Desulfuromonadales, and members of the Alpha- and Epsilonproteobacteria.
Bibliographical noteFunding Information:
This research was in the framework of the MELa3 Project, supported by the Infrastructures of the Ministry and Venice Water Authority through its Concessionary Consorzio Venezia Nuova. The authors thank Giulio Bernstein and Laura Montobbio of Consorzio Venezia Nuova for calling for this investigation and Ramona Marasco for excellent technical assistance. We also thank anonymous reviewers for helpful suggestions on manuscript improvement.
- Anthropogenic impact
- Microbial communities
- Sulfur species
- Venice lagoon
ASJC Scopus subject areas
- Molecular Biology