Spatial and Temporal Variations in Water Quality Parameters along the Kenyan Southern Coast: A Comparative Analysis of In Situ and Nutrient Data

The Kenyan Southern Coast, characterized by diverse aquatic ecosystems, faces challenges in maintaining optimal water quality due to anthropogenic activities and natural processes. There is a need for continuous monitoring to assess ecosystem health. This study examines the spatial and temporal variations in key water quality parameters along the Kenyan Southern Coast by integrating in situ measurements with nutrient data using both laboratory and field methods to provide a comprehensive assessment of coastal dynamics. Parameters such as temperature, salinity, dissolved oxygen, turbidity, electrical conductivity, total dissolved solids, total suspended solids, chlorophyll a and nutrient concentrations (nitrates, nitrites, phosphates, and ammonium) were analyzed across 6 sites in different seasons. Water quality and productivity assessments revealed elevated concentrations increased nutrient levels during the wet season and heightened salinity during the dry season, while spatial differences highlight localized influences such as riverine inputs and human activities; chlorophyll-a (Chl-a) levels (0.04±0.65 to 2.77±0.19 mg/L), nitrate (NO3⁻) (0.25±0.003 to 0.92±0.005), organic carbon content (5.80±0.17 to 7.26±0.03 mg/L), total suspended solids (TSS) (14.05±33.2 to 52.01±10.2 mg/L), Turbidity (0.18±0.17 to 0.19±0.07 NTU), total dissolved solids (TDS) (33591±15.9 to 33804±33.1 mg/L), electrical conductivity (EC) (53420±0001.5 to 54226±1277.80 μS/cm), phosphates (PO4³⁻-P) (0.13±0.003 to 0.16±0.003), nitrites (NO2-)-N) (0.14±0.0001 to 0.15±0.0001) and ammonium (NH4 +-N) (0.16±0.0070 to 0.50±0.0003). Comparative analysis of in situ data with nutrient trends underscores the role of nutrient enrichment in coastal eutrophication and ecosystem variability. The findings offer critical insights for coastal management, emphasizing the need for sustainable practices to mitigate anthropogenic impacts and enhance resilience in Kenya’s southern coastal waters to protect both human health and ecosystem integrity.