On the limnology of Lake Baringo (Kenya): II. Pelagic primary production and algal composition of Lake Baringo, Kenya

Primary production and algal composition were studied in the shallow, highly turbid tropical freshwater Lake Baringo (Kenya). The lake's primary productivity was found to be very low when compared to other neighbouring Rift Valley lakes. The mean value of daily gross primary production was 0.56 g O2 m−2 d−1 with a range of 0.22 – 0.70 g O2 m−2 d−1. The study showed that this lake's primary production is strongly influenced by the inorganic turbidity but not the self-shading of algae as observed in the neighbouring soda and alkaline lakes. The lake has a high aphotic:photic zone ratio of 19, thus leading to a low light adapted phytoplankton community capable of vertical movement. This was shown by a uniform chlorophyll-a concentration at night and a gradient with higher values near the water surface observed during day time, too. Mean chlorophyll-a concentration was 55 μg l−1. Lake Baringo is characterised by only low diversity of algae and cyanobacteria, the latter being the major group of phytoplankton in this lake. Few green algae and diatoms were recorded during this study, growing for the most part in gelatinous sheaths of the blue-greens (strategy to get some light), on the stones near the shores of the lake and attached to the macrophytes.