Dynamics of Eutrophication and Its Linkage to Water Hyacinth on Lake Tana, Upper Blue Nile, Ethiopia: Understanding Land-Lake Interaction and Process
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The increasing population has put an immense pressure on our natural resources leading to water pollution and land degradation. The need for new agricultural areas, urbanization and industrial development have been responsible for resources degradation and pollution. Eutrophication can be resulted due to substantial driven enrichment of seasonal cycle of nutrients like phosphorus and nitrogen. So, this study is aimed at evaluating the (1) spatial and temporal dynamics of eutrophication on Lake Tana, (2) linkage between eutrophication and water hyacinth infested area (3) lake-land linkage of nutrients and water hyacinth infestation. To evaluate the dynamics of eutrophication, the samples were taken from 143 points at 0.5 m depth of the lake in August (2016), December (2016) and March (2017). To see the lake-land linkage of nutrients, two major nutrients (P and N) were collected at the major tributary rivers. The trophic status index of TP, SDD and Chl-s was determined by adopting Carlson’s model by using spatial analyst tool of ArcGIS. The result of this study showed that the trophic status index of the lake is shifting from mesotrophic to eutrophic condition. The growth of the invasive weed in the northeastern part of the lake is caused by the spatial distribution of nutrient and eutrophication as well as the depth, wind direction and the extent of large floodplain. This study will help to manage and control the pollution of Lake Tana and the expansion of water hyacinth.
KeywordsEutrophication Spatial distribution Trophic sate index Geographic information system (GIS) Lake Tana Water hyacinth
The data used were collected by Bahir Dar University Ethiopia and International Water Management Institute (IWMI) as part of the Feed the Future innovation Lab for Sustainable Intensification (AID-OAA-L-14-00006) through the Sustainably Intensified Production Systems Impact on Nutrition (SIPSIN). We thank Tana Sub Basin Office (TaSBO) and Amhara Design and Supervision Works Enterprise, ADWE) to give us additional secondary data.
Minychl contributed in computation of the overall GIS work, data analysis, writing the manuscript and improving the manuscript based on the comments and suggestions of the coauthors. Aron contributed in the data collection and laboratory work. Fasikaw contributed in improving this manuscript by reviewing and editing the language as well as the images. Assefa contributed in conceptualization of the manuscript, giving comments, suggestions and improving the writing up and result interpretation. Seifu A. contributed in conceptualization of the manuscript, shaping the objectives, the methods and in giving comments and suggestions for the overall work as well. Abeyou played a great role in the GIS part for example in improving the quality of images. Mamaru contributed in shaping the overall contents, English, structure of the paper and giving significant comments. Desalegn Contributed in editing, improving the English and in giving significant comments for the paper.
Conflict of Interest
The authors have declared no conflict of interest.
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