The Adaptation of Selected Pathogenic Microbes to Elevated Temperature and Their Detection In Situ in the Coastal Marine Environment

Marine pathogens, both indigenous and introduced ones, play an important role in determining marine bacterial communities and the number of new marine diseases has increased recently. Mass mortalities due to disease outbreaks have recently affected major taxa in the coastal environment. The global warming might be related to the onset of diseases because of direct effect of the increase of sea water temperature or/and indirectly due to changes in pH or salinity that contribute to the microorganisms' proliferation. One example of such microorganism are bacteria from the genus Vibrio. Several laboratory experiments were performed to investigate the effects of different salinity and temperature conditions, with the Vibrio strains (Vibrio sp., V. harveyi, V. chagasii strains) isolated from the seawater collected in the Gulf of Trieste (Northern Adriatic). Bacterial growth rate, respiration, ectoenzymatic activities together with quality and quantity of inorganic and organic matter pool were followed in order to survey the changes in physiological and biochemical processes linked to different temperature conditions, which simulate the upper limit of sea surface temperatures in the Adriatic Sea. In addition, the detection and quantification of all selected Vibrio strains was performed in situ using validated specific real time quantitative PCR assays. We sampled at different stations and depths, from the estuary to open waters, as well as near the discharge of the treatment plant in order to study the impact of anthropogenic wastewater discharges of these pathogens on the coastal ecosystem.