Integrated Evaluation of Environmental Parameters Influencing Vibrio Occurrence in the Coastal Northern Adriatic Sea (Italy) Facing the Venetian Lagoon
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In the marine environment, the persistence and abundance of Vibrio are related to a number of environmental parameters. The influence of the different environmental variables in determining the Vibrio occurrence could be different in the specific geographic areas around the world. Moreover, oceanographic parameters are generally interdependent and should not be considered separately when their influence on bacterial presence and concentration is tested. In this study, an integrated approach was used to identify key parameters determining the abundance of Vibrio spp in marine samples from the Venetian Lagoon in Italy, which is an important area for fish farming and tourism. Multivariate techniques have been adopted to analyze the dataset: using PCA, it was shown that a relatively high proportion of the total variance in this area was mainly due to two independent variables, namely salinity and temperature. Using cluster analysis, it was possible to categorize different groups with homogeneous features as regards space (“stations”) and time (“seasons”) distribution, as well as to quantify the values of environmental variables and the Vibrio abundances in each category. Furthermore, integrating key environmental factors and bacterial concentration values, it was possible to identify levels of salinity and sea surface temperature which were optimal for Vibrio concentration in water, plankton, and sediment samples. The identification of key environmental variables conditioning Vibrio occurrence should facilitate ocean monitoring, making it possible to predict unexpected variations in marine microflora which determine possible public health risks in coastal areas.
KeywordsVibrio West Nile Virus Total Suspended Matter Rift Valley Fever Venice Lagoon
The Vibrio environmental strains analyzed in this study were isolated within the framework of the international research project VibrioSea, which was co-funded by the Centre National d’Etudes Spatiales (CNES), the Institute Pasteur, France, and the Universities of Verona and Genova, Italy.
The authors wish to express their thanks for helpful discussions with the VibrioSea consortium, which included the following institutions: the University of Verona, University of Genova and ISMAR–CNR Venezia (Italy), CNES, MEDIAS-France, CLS, IFREMER and Institute Pasteur Paris (France), and the Institutes Pasteur in Morocco, Algeria, and Tunisia.
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