Abstract:
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.
