Environmental study in Cabras lagoon: the trophic state and the microalgal component with particular attention to harmful algal species

The implementation of the knowledge regarding the trophic state, the composition and dynamics of phytoplankton in Cabras lagoon was the principal aim of this PhD thesis, to improve the comprehension of recurrent stressing events that have often injured the stability of the ecosystem. The chapters constituting the work, investigate these thematic and show the results obtained during this PhD and those obtained during previous studies, elaborated in this occasion to compare the different series available for Cabras Lagoon. In the complexity of this study, among phytoplankton, a key rule was carried out by the Cyanophyceae Class, that resulted the most important since 1999, when, in summer, a bloom of the cyanobacterium Anabaena cf. mucosa Komarkova-Legnerova and Eloranta was observed simultaneously with the strongest dystrophic crises that struck the lagoon. The high trophic state of the lagoon, confirmed nowadays, the affirmation of phytoplankton species of small size and the dominance of cyanobacteria seem to be the main ecological aspects characterizing this ecosystem. Moreover the study of the lagoon sediment, in terms of presences and dynamics of dinoflagellates cysts, confirmed potentially scarce and sporadic presence of dinoflagellates, already observed in the water column, and more specifically the scarce and sporadic presence of Harmful Algal Species (HAS), which for the most part belong to this class.