Phytoplankton community in abu-qir bay as a hot spot on the southeastern mediterranean coast
Shams El-Din, N.G.
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The phytoplankton community in the stressed part of Abu Qir Bay was studied monthly relative to the prevailing ecological conditions from April 1998 to March 1999 at eight stations. The study recorded a total of 182 species of both fresh and marine origins, belonging to diatoms (89 species), chlorophytes (34 species), dinoflagellates (26 species), cyanophytes (18 species), euglenophytes (12 species), silicoflagellates (2 species), and cryptophyte (one species). Most of the recorded species occurred either seasonally or rarely, while small number of them appeared as persistent. The diversity of the phytoplankton community experienced wide variations on both monthly and spatial scales, accompanied by analogous variations in the diversity index, richness and evenness. The phytoplankton count was low (0.01 x 103 - 12.5 x 103 unit/L) all the year round, except high density in September (55.6 x 103 units/L). In contrast, chlorophyll-a attained markedly high values over the year (2.06 – 52.64 _g/L). The diatoms Nitzschia pungens and Asterionella japonica were the predominant, in addition to Chaetoceros affinis, Thalassionema nitzschioïdes and the dinoflagellate Prorocentrum micans. The phytoplankton count showed insignificant correlation with the nutrient salts, may be due to the water deterioration, resulting from the acute eutrophication and the increase of pollution stress in the bay. The present study revealed a marked drop in phytoplankton abundance as compared to the earlier records.