Spatial and temporal variations of trophic state conditions of Lake Bunyonyi, south‑western Uganda
The study was conducted to assess the spatial and temporal variations of the trophic state condition of Lake Bunyonyi between October 2019 and September 2020. Secchi depth (SD), total phosphorus (TP) and chlorophyll-a (Chl-a) concentration were measured to aid the quantification of trophic state c...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | en_US |
| Published: |
Springer
2022
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.12493/748 |
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| Summary: | The study was conducted to assess the spatial and temporal variations of the trophic state condition of Lake Bunyonyi
between October 2019 and September 2020. Secchi depth (SD), total phosphorus (TP) and chlorophyll-a (Chl-a) concentration
were measured to aid the quantification of trophic state condition of the lake using Carlson trophic state index (CTSI).
The trophic state index (TSI) values based on SD, TP and Chl-a values were 60.82 ± 5.35, 68.99 ± 11.04 and 61.74 ± 7.51,
respectively. March 2020 recorded the highest mean CSTI value (70.14 ± 4.04), while in September 2020, the lowest mean
value (58.03 ± 6.22) was obtained. Based on CTSI values, the lake was eutrophic in both dry and wet seasons albeit with
differences in the values. The eutrophic state of the lake is possibly attributed to nutrients inflow into the lake via runoff
and drainage from farmlands. The negative value of TSI-Chl-a–TSI-TP deviation pointed out that the lake is not phosphorus
limited, while the positive TSI-Chl-a–TSI-SD mean deviation value revealed the effect of Chl-a and TP on the lake’s
transparency. The study recommends the necessity to develop guidelines for the trophic status monitoring of Lake Bunyonyi
since results suggest the deteriorating lake condition. |
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