DOI: 10.36347/sajb.2021.v09i12.003

Pages: 395-404

Recent researches have suggested that atmospheric depositions are a major source of nutrients to aquatic ecosystems. It is important to identify and quantify nutrients deposited into surface water and the relationship with wind direction and wind speed to understand the contributing sources of nutrient deposition to Lake Kivu. This study analyzed the relationship of the contribution of TP and TN from the atmospheric deposition with wind direction and wind speed during the period 2017-2019 using regression analysis. Atmospheric deposition of nutrients (TP and TN) and lake water were analyzed in the laboratory for TP and TN using standard analytical methods. Wind speed (m/s) and wind direction (o) were collected at Lwiro station using automatic sensor and gaps were filled by data downloaded from NASA/POWER SRB/FLASHFlux/MERRA2/GEOS website. Temporal variation of TN and TP atmospheric deposition rates is significantly different over time (p<0.000) at Lwiro station. Natural and anthropogenic activities in the watershed such as volcanic activities, biomass burning, and soil erosion introduce particles in the atmosphere following meteorological conditions and surface lake water becomes nutrients rich due to increasing nutrients input. It was observed that the average high rates of nutrients were coming more from the north part of the Lake (Goma) than other points. Volcanic and traffic activities were identified as being the main sources of nutrients in the north part of the watershed and appear to play an important role in the Lake eutrophication. The results can serve as a baseline as far as atmospheric nutrient loading sources in Lake Kivu watershed are concerned and suggest strategies for future assessment.