Seasonal variation of water quality and phytoplankton dynamics and diversity in the surface water of Boukourdane Lake, Algeria

A study of phytoplankton diversity and its seasonal variation was conducted by sampling water from Boukourdane Lake between February 2013 and January 2015. Fifteen physical and chemical variables were recorded, and their relationship with the density of 162 phytoplankton species was established using Canonical Correspondence Analysis, which showed that the density of phytoplankton was higher when minerals and nutrients increased. An anthropogenic impact was also most evident in structuring phytoplankton assemblages at sites close to the lake where agriculture was concentrated. The results obtained from the Margalef, Shannon–Wiener, and Equitability diversity indices indicated mediocre water quality. Determinations of the trophic state were made by examining several diverse criteria, such as transparency and the concentrations of chlorophyll a and phosphorus. Our study area was characterized as mesotrophic according to the Organisation for Economic Co-operation and Development classification.