Assessment of phytoplankton community structure and water quality in the Eastern Harbor of Alexandria, Egypt

The species composition and abundance of phytoplankton were studied weekly from 16 June 2011 to 30 May 2012 at a fixed station in the Eastern Harbor (EH), a semi-closed basin; in Alexandria City The results indicated that, the phytoplankton standing crop varied between a minimum of 1.08 × 103 and a maximum of 1.57 × 106 cells·l−1. The phytoplankton community was represented by a total of 132 species, including 72 diatoms, with a percentage frequency of 96.42% and 37 dinoflagellates (3.34%), as well as few representatives of different freshwater groups. The Shannon–Wiener diversity, varied broadly from 0.0076 to 3.19 bits. cell−1, Stable community accompanied the low values, while higher diversities corresponded to non-steady state periods. Water quality was estimated according to phytoplankton density and based on inorganic nutrient data (P-PO4, N-NO3, N-NO2, N-NH3), the aquatic system was divided into oligotrophic, mesotrophic and eutrophic water types. A correlation coefficient of biological factors with some environmental conditions are provided and discussed. Further, Principle Component Analysis (PCA) which was used to analyze water quality of weekly data and its results were discussed. © 2019 National Institute of Oceanography and Fisheries