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Identifier

000419793

Title

Οι επιπτώσεις των ανθρωπογενών περιβαλλοντικών πιέσεων στις κοινότητες ιών και βακτηρίων σε παράκτια οικοσυστήματα

Alternative Title

Impact of anthropogenic environmental pressures on viral and bacterial communities of coastal ecosystems

Author

Τσιώλα, Αναστασία Ε.

Thesis advisor

Καρακάσης, Ιωάννης

Reviewer

Πήττα, Παρασκευή
Κωτούλας, Γεώργιος
Καραγιάννη, Ήρα
Κουμουνδούρος, Γεώργιος
Λαδουκάκης, Εμμανουήλ
Τσαπάκης, Μανώλης

Abstract

In this PhD dissertation, the relationship between lysogeny and four different conditions of anthropogenic environmental pressure was examined. The stucture of viral and bacterial communities was also described in relation to these pressures. The four conditions reflect anthropogenic environmental pressures that are either currently taking place in a large, medium or small scale, or predicted for the future.In particular, the first pressure concerns the input of engineered silver nanoparticles into the marine ecosystem, which is projected to increase in the near future with significant and unexplored impacts on plankton. The second pressure concerns the carbon dioxide input and the induced reduction in seawater pH, which is a chemical change that has already been measured in the oceans and is projected to continue. The third pressure is also a recorded chemical change in the marine ecosystem caused by the influx of contaminated aerosols. In the Mediterranean Sea, these aerosols are mainly of European origin and their entry causes changes in the balance of essential nutrients. Finally, the fourth pressure includes various anthropogenic activities that take place in the coastal waters along the Greek coastline that cause continuous chemical alterations. For example, the release of either heavy metals from industries or nutrients from aquaculture are two representative examples observed in these coastal systems on a continuous basis. Therefore, for the fourth study, natural communities were analyzed by field sampling to map the bacterial and viral community at a given time. In contrast to the fourth study, the experimental tool of the mesocosms, which is extensively applied to study specific pressures in the pelagic ecosystem, was used in the first three chapters, allowing experimentation on a large scale, with good repeatability and with all the trophic levels present. Knowing already that these pressures affect the bacterial communities, the aim of the dissertation was to check whether the influence is also observed at the level of the viral genome and/or on the viral life cycles. A basic hypothesis of the experiments was that if the pressures had a negative effect on planktonic bacteria, the effect would be primarily visible to viruses too, as viruses are a biological entity that controls and often stimulates cellular responses to higher trophic levels. In order to test the hypothesis, quantitative methods (production of lytic and lysogenic cells) and qualitative methods (genomic analysis) were used.

Language

Greek

Subject

Anthropogenic activities

Marina microbiology

Microbial ecology

Viral and bacterial communities

Ανθρωπογενείς επιβαρύνσεις

Θαλάσσια μικροβιολογία

Κοινότητες ιών και βακτηρίων

Μικροβιακή οικολογία

Issue date