Seasonal phytoplankton variations in the shallow Pahlavi Mordab,Iran

Pelagic phytoplankton variations in the shallow, western basin of the Pahlavi Mordab, Iran were monitored by the chlorophyll a, gross oxygen productivity and cell enumeration techniques. Annual maxima were 29.4 mg/m³, 0.98 mg O₂/l/hr and 32, 639, 467 cells/liter respectively and were recorded from late summer until early autumn. During the spring and summer, dense growths of Ceratophyllum, Hydrilla and Myriophyllum flourished. Competition between the phytoplankton and submerged aquatic macrophytes was minimal following late summer, when water depths increased following heavy seasonal precipitation and the die-back of submerged aquatic macrophytes occurred.