Cyanobacteria harmful algal blooms (cyanoHABs) pose a threat to water quality and human health. The Lake Naivasha, Kenya community expressed concern about these events which prompted this study of influences, characteristics and health impacts of cyanoHABs. While eutrophication of Lake Naivasha was caused by years of nutrient loading from agricultural activities, land use changes and improper sewage treatment, results suggest that lake-wide cyanoHAB formation was controlled by shifts from drought to flood conditions, followed by relative stability. Particulate concentrations of the liver toxin microcystin were less than provisional guidelines; however, our limited knowledge on long-term microcystin impacts is limited and future cyanoHABs could have higher levels. CyanoHABs may play a role in dissolved oxygen dynamics and in turn fish health, but the extent of this is unclear without further study. Better management practices of Lake Naivasha’s ecosystem services will lead to enhanced health and wellbeing of the lake and community
