Aquatic biodiversity and saline lakes: Lake Bogoria National Reserve, Kenya

Lake Bogoria, in the Rift Valley of Kenya is an extreme saline lake (conductivity 40–80 mS cm-1, alkalinity 1500 m equ 1-1). It is hydrologically more stable than the other, endorheic lakes in Kenya, because it is deep — maximum depth at present just over 10 m in an area of 3000 ha — and so does not have periods when it is dry. It is ecologically simple, with only one species dominating the phytoplankton — the cyanobacterium ‘spirulina’, Arthrospira fusiformis. Its biomass and productivity were very high — biomass between 38 and 365 μg 1-1 chlorophyll ‘a’ and 3.4–21 x 103 coils ml-1 and net production between 0.24 and 1 gm C m3 h, the latter in a narrow zone of less than a metre. There were…