Lake Turkana. Limnological study 1985-1988

Abstract

The lake level was declining during the study and reached the lowest level ever recorded in 1988. The salt content was increasing and the conductivity reached ca 380 mS/m in 1988. Annual temperature variations were small, but sufficient to create thermal stratification in March-May. Low deep water oxygen concentration was observed during stratification, especially in 1988. the development of phytoplankton was limited by the availability of nitrate and light. Light limitation was caused by turbid water and vertical mixing. The gross phytoplankton primary production was 2.4-8.2 g O2/m"/day and the estimated total annual production ca 2 kg O2/m". The total zooplankton production was estimated , the sustainable yield of traditionally exploited fish from the open lake was estimated to rough 15 000 - 30 000 tons/year.