Ecology, Environment and Conservation Paper

THE INFLUENCE OF CYANOPHYCEAE BLOOM ON ZOOPLANKTON POPULATIONS IN EL-BAHR EL-PHARAONY CANAL, EGYPT

Nehad Khalifa, Howayda H. Abd El-Hady and Shymaa S. Zaher

Abstract

Lentic ecosystems range from a small, temporary pond to big lakes, El-Bahr El-Pharaony is one of the most important lentic ecosystems in Egypt. The objective of the present work was to study zooplankton composition in relation to spring Cyanophyceae bloom in El-Bahr El-Pharaony. Chlorophyll a and biochemical contents of phytoplankton were measured concurrently. Ninety phytoplankton taxa were recorded belonging to 5 classes, Cyanophyceae are the dominant phytoplankton components particularly at site 7, where it constituted about 99.61% and affected the transparency and dissolved oxygen values to minimum of 10 cm and 4.4 mg/L. Main cyanobacterial species were Microcystis aeruginosa, Microcystis flosaquae, Merismopedia tenuissima and Merismopedia glauca. The high content of protein in phytoplankton may be related to the bloom of Microcystis flos-aquae and elevation in carbohydrates due to flourishing of Merismopedia. Rotifers obtained density and species richness superior to the other zooplankton groups; it was dominated by Brachionus budapestensis, Brachionus angularis and Polyarthra vulgaris. The dominance cyanobacteria forms Microcystis and Merismopedia, the abundance of various eutrophic and pollution indicators like Brachiouns and changes in their constituents as biomarkers indicate deterioration of El-Bahr El-Pharaony water if no measures are taken.