Modelling nitrogen transformation in the Lake Bunyonyi ecosystem, South‑Western Uganda
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Springer
Abstract
Lake Bunyonyi is one of the major resources of social-economic potential in the districts of Rubanda and Kabale, South-
Western Uganda. The lake’s sub-catchment faces environmental problems because of intensive agriculture, settlement,
business and tourism activities, which consequently cause pollution of water in the lake’s system. This study, therefore,
intended to determine the processes that govern nitrogen dynamism using a numerical model that takes into account various
processes in the system using STELLA® 8.1.1 software. From the model simulation, it was found that mineralization,
microbial uptake and nitrification were the major processes governing nitrogen transformation in the water phase, accounting
for 47.8% (0.49 g/d m−2), 44.2% (0.45 g/d m−2), and 7.8% (0.05 g/d m−2), respectively. The developed model predicted
reasonably well the behaviour of the lake evidenced by the validation results of observed and simulated data that showed
good linear regression coefficients (R2) of organic nitrogen (0.48), ammonia–nitrogen (0.68), and nitrate–nitrogen (0.61).
The model has proven suitable for application on lakes with characteristics similar to that of Lake Bunyonyi. The study
recommended that a compressive investigation that puts into consideration all the possible sources of nutrient and water
inflow into the lake system be done on Lake Bunyonyi.
Description
Keywords
Denitrification · Lake Bunyonyi · Mineralization · Nitrification and nitrogen dynamics