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Seasonal periodicity of plankton and benthic fauna community structure and diversity in a small N orth A frican reservoir
Author(s) -
Iskaros Isaac A.,
ElOtify Ahmed M.
Publication year - 2013
Publication title -
water and environment journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 37
eISSN - 1747-6593
pISSN - 1747-6585
DOI - 10.1111/wej.12003
Subject(s) - benthic zone , zooplankton , phytoplankton , fauna , plankton , ecology , biota , biology , species richness , oceanography , geology , nutrient
Aquatic biota in terms of phytoplankton, zooplankton and benthic fauna were qualitatively and quantitatively followed seasonally during 2007 in a N orth A frican small reservoir, A swan R eservoir. Simultaneously, seasonal variations in water quality were investigated in order to determine how far the aquatic biota could be altered by physicochemical and biotic factors. In phytoplankton of the investigated reservoir, 75 species belonging to four systematic groups were recorded, comprising 11 C yanoprokaryota, 24 B acillariophyceae, 2 D inophyceae and 38 C hlorophyceae. Most numerous zooplankton were R otifera (23 species). C ladocera and C opepoda were less numerous, with only seven and three species, respectively. Early development stages of copepods, nauplii and copepodites were sometimes recorded in considerable numbers. Twenty‐two invertebrate species related to five animal groups were exclusively benthic fauna: three O ligochaeta, nine M ollusca, seven larvae of C hironomidae, one P latyhelminthes, one H irudinea and one D ecapoda. Generally, the estimated values of phytoplankton species richness were relatively higher than those of zooplankton or benthic fauna. In particular, phytoplankton was influenced by physicochemical factors – water transparency, salinity and soluble reactive silica contents – as well as biotic factors – zooplankton and benthic fauna. Levels of pH value, Mg +2 , NO 3 ‐ N and chlorophyll‐ a contents appeared to be the most influential parameters dictating the pattern of seasonal periodicity of benthic fauna. Numerically, the phytoplankton was somewhat more abundant in winter and autumn than in spring or summer. The peak of zooplankton population densities was observed in spring season. Benthic fauna tended to be abundant in summer and autumn seasons, showing a reverse seasonal trend from that of zooplankton. C yanoprokaryota and B acillariophyceae were the most important groups that determined the seasonal fluctuation pattern of phytoplankton. R otifera and C opepoda were the most predominant groups influencing the seasonal periodicity of zooplankton. O ligochaeta and M ollusca alternated the dominancy of benthic fauna community in A swan R eservoir.