Spatial and temporal variations of phytoplankton composition and biomass in Lake Bunyonyi, South‑Western Uganda
The purpose of this study was to examine the spatial and temporal variations of phytoplankton species composition and biomass in Lake Bunyonyi, South-Western Uganda. Samples were collected monthly from nine fixed stations in the lake from October 2019 to September 2020. Based on the morphologic...
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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/20.500.12493/747 |
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| Summary: | The purpose of this study was to examine
the spatial and temporal variations of phytoplankton
species composition and biomass in Lake Bunyonyi,
South-Western Uganda. Samples were collected
monthly from nine fixed stations in the lake from
October 2019 to September 2020. Based on the morphological
characterization, 52 different species of
phytoplankton were recorded. These were dominated
by cyanobacteria (21 species) and chlorophytes (15
species) followed by diatoms (10 species), euglenophytes
(4 species), dinoflagellates (2 species),
and cryptophytes (1 species). The biomass (Chl-a
concentration) ranged from 0.019 ± 0.009 mg/L at
Heissesero station to 0.045 ± 0.013 mg/L obtained
at Nyombe station. On a temporal basis, the highest
mean Chl-a concentration of 0.044 ± 0.03 mg/L was
recorded in March 2020 while the least concentration
of 0.015 ± 0.011 mg/L was obtained in September 2020. Significant differences existed in the Chl-a concentration
values between stations and across sampling
months. Chl-a concentration was significantly
positively correlated with dissolved oxygen (DO), turbidity
but negatively correlated with temperature. The
Shannon–Wiener index and evenness put it clear that
the distribution of phytoplankton species in the lake is
inequitable. Besides, 94.2% of the phytoplankton species
revealed had never been reported by the previous
studies in the study area. The dominance of species
cyanobacteria (such as Microcystis spp., Cylindrospermopsis
raciborskii, Anabaenopsis sp., and Anabaena
sp.) presents potential future challenges to
water quality management. Therefore, the establishment
of a strong and committed committee dubbed
“Lake Bunyonyi Water Management Committee” to
oversee the activities and avert potential water quality
challenges is strongly recommended. The existence
of some toxic phytoplankton species calls for regular
monitoring and careful use of the lake and its food
products. |
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