Spatio‐temporal variations in the trophic status of L ake N aivasha, Kenya

• Published in: Lakes & Reservoirs : Science, Policy and Management for Sustainable Use Vol. 18; no. 4; pp. 317 - 328
• Main Authors: Ndungu, Jane, Augustijn, Denie C. M., Hulscher, Suzanne J. M. H., Kitaka, Nzula, Mathooko, Jude
• Format: Journal Article
• Language: English
• Published: 01.12.2013
• ISSN: 1320-5331; 1440-1770
• DOI: 10.1111/lre.12043

Abstract The spatio‐temporal dynamics of the trophic state of a lake are crucial in defining its water quality, as well as biodiversity. Accordingly, this study focused on the spatio‐temporal variations of the trophic state, and the possible causes of the heterogeneous turbidity in Lake Naivasha, Kenya. The trophic state of the lake oscillated between a eutrophic and hypereutrophic condition, being found to be more eutrophic than reported in previous studies, indicating a progressive deterioration of its water quality. Inferences from the graphical representation of the deviations of total phosphorus and Secchi depth from the chlorophyll‐ a trophic state indices revealed that the lake is predominantly phosphorus limited. Furthermore, the turbidity in the northern part of the lake is dominated by suspended sediment and dissolved coloured material. Discriminant analysis resulted in identification of three distinct trophic state regions in Lake Naivasha, namely the northern region, the mid and southern part and the more or less isolated Crescent Lake. The results of this study provide a good basis for further investigation of the current loading magnitude of both nutrients and sediments, in order to facilitate sustainable management to ensure community integrity and ecosystem functions of the lake.