Effects of water quality on phytoplankton diversity and abundance in Nairegie Enkare Dam, Narok County, Kenya

Freshwater ecosystems are increasingly being degraded by human activities such as agricultural runoff, industrial discharge, urbanization and poor waste management. These activities lead to the introduction of excessive nutrients, particularly nitrogen and phosphorus, into water bodies, which causes eutrophication, leading to excessive growth of phytoplankton and potentially triggering harmful algal blooms, especially cyanobacteria, which can produce toxins harmful to aqu7667atic organisms, livestock, wildlife, and humans. Therefore, the knowledge of water quality and phytoplankton communities is crucial for the successful management of freshwater ecosystems.

The study seeks to assess the impact of water quality parameters on phytoplankton diversity and abundance in Nairegie Enkare Dam, Narok County, Kenya in the rainy season. Physicochemical parameters and phytoplankton communities will be assessed using a quantitative research design. Water sampling will be conducted in June and July, 2026 using both purposive and vertical sampling techniques to capture the variation in depth and location within the dam. In-situ measurements will include pH, temperature, turbidity, electrical conductivity and dissolved oxygen. Laboratory analyses will determine concentrations of total phosphorus, total nitrogen, nitrates, nitrites and ammonia using standard procedures. Phytoplankton samples will be preserved in Lugol’s solution and identified according to standard taxonomic procedures.

Species abundance and diversity will be analyzed by the Shannon-Wiener diversity index. Statistical analyses such as one-way ANOVA and Tukey’s HSD test will be employed to determine significant relationships between water quality and phytoplankton communities. The results will help manage freshwater resources, conserve biodiversity, monitor ecosystem health and deliver Sustainable Development Goal 6 on clean water and sanitation.