Effect of land use on water quality and phytoplankton community in the tropical Khami River in semi-arid southwest Zimbabwe
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Date
2017-01
Authors
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Publisher
NISC
Abstract
The water quality and phytoplankton community assemblage of the Khami River, a tropical river sub catchment
in semi-arid southwest Zimbabwe impacted by agriculture and urban land use, were examined in March 2015.
Conductivity, sulphates, total dissolved solids and salinity were higher at urban sampling points than at agricultural
sampling points. In contrast, agricultural sampling points were more turbid, and had a greater content of
nitrates than urban sampling points. The phytoplankton community was dominated by Cyanobacteria, mainly
Microcystis aeruginosa, with densities of up to 20 times higher at urban than at agricultural sampling points.
There was an increasing dominance of Cyanobacteria (M. aerugionosa and Merismopedia glauca) and Chlorophyta
(Eudorina elegans, Spirogyra sp. and Pediastrum duplex) and a decreasing importance of Bacillariophyta along the
agriculture-to-urban gradient. Given the increasing scarcity of water in southern Africa, not only do our findings
confirm the importance of land use types as drivers of water quality and phytoplankton community composition
and structure. However, they also show that Cyanobacteria, Chlorophyta and Bacillariophyta can be indicators of
changes in water quality, factors that will prove pertinent to management for effective water quality management
using phytoplankton composition as bioindicators.
Description
Journal Article
Keywords
agriculture, aquatic ecosystems, diatoms, pollution, species composition, streams
Citation
Dzinomwa T., Ndagurwa H.G.T. 2017. Effect of land use on water quality and phytoplankton community in the tropical Khami River in semi-arid southwest Zimbabwe : African Journal of Aquatic Science 42(1): 83–89