The objective of this course for the students to be able to: 1) Combine water physicochemical characteristics and geomorphological data of the area with the living organisms of the aquatic environment 2) Assess physical and chemical factors, that control populations, communities and ecosystems in aquatic environment 3) Combine abiotic and biotic parameters for the comprehension of the structure and the function of aquatic ecosystems 4) Classify aquatic organisms according to their lifestyle and distribution to the aquatic environment 5) Discriminate planktonic organisms and explain their interactions 6) Qualitatively (basic taxonomic groups) and quantitatively assess phytoplankton and zooplankton samples and understand their importance for oceanographic, fisheries and environmental studies 7) Discover applications of Hydrobiology to Aquaculture and Biotechnology.