Effects of seasonal changes on the depletion of microflora in natural wetlands in Northern KwaZulu Natal
Loading...
Date
2017
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Zululand
Abstract
Natural wetlands are known for their ability to improve water quality through purification and sinking of nutrients and carbon in the sediments. The interactions occurring between microorganism and macrophytes at the rhizosphere also aid in water quality improvement in natural wetlands. In some rural communities, humans consume water directly from wetlands. They also harvest wetland plants for housing and fish for consumption. Increasing population due to urbanisation and industrialisation has emerged with the aggravation of water pollution due to informal settlements with poor sanitation located close to wetlands. This threatens the wellbeing of the natural ecosystems. Various physiochemical parameters and microbial communities were evaluated at Lake Cubhu to determine the effects of seasonal changes on the microbial community structure of this lake. Lake Cubhu wetland is a sub-catchment within the Mhlatuze catchment and it is surrounded by various small scale farms. Esikhaleni Wastewater Treatment works is also within this sub-catchment and it uses this wetland as its effluent recipient. The analysis of temperature, pH, dissolved oxygen, ammonium, nitrate, nitrite, phosphate and chemical oxygen demand from water samples was done within 24 hours after sampling to determine the seasonal effects on physiochemical parameters. The physiochemical parameters were found to be within the standard limits set by the Department of Water Affairs and Forestry in its Water Quality Guidelines for Aquatic Ecosystem volume 7 and World Health Organisation (WHO). Chemical oxygen demand was the only parameter that was above the standard limit with the maximum values > 100 mg/l. This was attributed to the high organic matter contents from the wastewater treatment works and anthropogenic pollution. The microbial communities from soil samples were analysed using the Illumina MiSeq sequencing. The bacteria were the most abundant >90% seasonally. The phyla Proteobacteria and Actinobacteria were the dominant phyla. The classes of Proteobacteria were all represented: Gamma-, Delta-, Alpha- and Betaproteobacteria. These classes of bacteria influenced the physiochemical and fluctuations which is further explained in this work. Their abundance was also dependent on the physiochemical parameters and nutrient. The results obtained suggested that seasonal changes have an effect on the depletion of microflora in natural wetlands. It is therefore important that seasonal changes are studied in order to gain understanding on the microbial community dynamics in natural wetlands.
Description
A dissertation submitted to the Faculty Of Science and Agriculture in fulfillment of the requirements for the Degree Of Master Of Science (Microbiology) in the Department Of Biochemistry and Microbiology at the University Of Zululand, 2017
Keywords
seasonal changes --microflora --microorganism --water quality --wetlands --South Africa