Physical, Chemical, and biotic influences on Zooplankton Composition in Zaranik Lagoon, Egypt

En Zaranik Protected Area encompasses the eastern end of Lake Bardawil: the Zaranik Lagoon. The lagoon is shallow, with numerous small islets scattered throughout it, most of which are covered with dense saltmarsh vegetation. Nitrogenous and phosphorus forms (ammonia, nitrite, nitrate, orthophosphate and total phosphorus) were studied as a basic nutrient salts affected different flora and fauna of the studied area. Nitrite was depleted completely during the study period except for winter. The nitrate values were fluctuated in a relatively narrow range (23.5 – 60 µg/l). Ammonia was detected in a normal range varied between 89-172 µg/l. Both orthophosphate and total phosphorus exhibit similar distribution dynamics. A total of 45 zooplankton species belonging to 9 main groups (Protista, Copepoda, Rotifera, Cladocera, Pteropoda, Cheatognatha, Cnidaria, Appendiculariae, and meroplankton) were recorded. Copepoda were the most abundant and ubiquitous zooplankton organisms in Zaranik protectorate, forming the 63 % of total zooplankton density. Salinity showed a negative correlation with total Protista (r = - 0.77) while NH3 showed a positive correlation with total zooplankton (r = 0.68).