The phytoplankton of Great Bitter Lake, Egypt, including the impacts of nutrient-laden and heated effluents
A year-long survey of the phytoplankton and nutrients in Great Bitter Lake indicates that this is a severely eutrophic lake. Chlorophyll levels were consistently high (>30g/l), especially in summer (>90g/l). The phytoplankton community comprised mostly diatoms and blue-green algae, although dinoflagellates and green algae were important at times. Local effects of effluent from a drain coming from the city of Ismailia were evident, although the effect of tourist hotels at Palma Beach was not detectable. The discharge of heated water from a thermal power plant raised the water temperature in the impacted area by 13°C in autumn and 22°C in summer and also caused decreases in chlorophyll and phytoplankton abundance. Dissolved nutrient levels were high and, especially at the offshore station, had a rather constant ratio of dissolved inorganic nitrogen to phosphate. The distribution of phytoplankton and chlorophyll were related more to temporal, presumably seasonal, variation than proximity to point sources of pollution.