Assessment of Water Quality, Phytoplankton, Zooplankton and Trophic Interaction of Lake Tinshu Abaya in Partial Fulfillment of the Requirement for Master of Aquatic Ecosystem and Environmental Management (AEEM)
| dc.contributor.advisor | Tadesse Fetahi | |
| dc.contributor.advisor | Demeke Kifle | |
| dc.contributor.author | Yordanos Getachew | |
| dc.date.accessioned | 2025-08-31T23:13:03Z | |
| dc.date.available | 2025-08-31T23:13:03Z | |
| dc.date.issued | 2023-06 | |
| dc.description.abstract | Freshwater ecosystems are subjected to various anthropogenic activities, which result water quality degradation and ultimately affect the overall functioning of ecosystem. Therefore, p monitoring and evaluating fresh water ecosystems limnological and biological aspect is crucial. To design sustainable resource the present aimed to assess some physico-chemical and biological water quality parameters, the trophic structure and energy flow of the lake. Samples were taken monthly from three sites from May to August 2022. All the data samples were collected and analyzed using standard methods of sampling and analysis. Composite samples were used for phytoplankton analysis, while 70μm mesh size plankton nets were used for zooplankton sampling. The trophic interactions, energy flows, and ecosystem properties of ecosystem were analyzed by ecotrophic modeling using Ecopath with Ecosim software (EwE, 6.6 version). Primary and secondary data were used to construct the mass balance model of the lake ecosystem. The results indicate that the lake had fairly high temperature (20.83_25.01 oC), and was well oxygenated (7.42_13.86 mg L-1). had very turbid water (350 - 735 NTU) and shallow Secchi depth (0.082 m) and high levels of nutrients and alkalinity. The levels of all physicochemical parameters considered in the study did not differ significantly among sites (ANOVA, p> 0.05) although their temporal variations were statistically significant (ANOVA, p < 0.05). The N:P Redfield ratio indicates that the limiting nutrient in the lake phosphorus. The results of principal component analysis show the contribution of TDS, Temperature, nitrate, nitrite, ammonia and Turbidity to water quality was high, while those of SRP and SiO2 was low. A total of 32 phytoplankton taxa belonging to 6 divisions including Bacillariophyta (Diatoms), Chlorophyta (Green algae), and Cyanobacteria (Blue-green algae), Euglenophyta (Euglenoids), Cryptophyta, and Dianophyta. The cyanobacteria were the most abundant during the all sampling months and followed by Bacillariophyta. Phytoplankton biomass as Chl-a ranged from 9.12 to20.08 μg L-1, with a mean value of 14.6 μg L-1. The minimum value was recorded during the rainy season (July) while the maximum was in May. Redundancy Analysis (RDA) of the relationships between environmental parameters and distribution of abundant phytoplankton showed that Cylindrospoermopsis cuvispora and Cylindrospoermopsis raciborski were correlated positively with TDS, Conductivity and turbidity. 25 typical tropical species of zooplankton were identified in samples from the lake, of which 60% species belonged to Rotifera, while 8% of the species belonged to Copepoda and 32% to Cladocera. Total zooplankton abundance was dominated by copepods followed by rotifers. Among the rotifers. Brachionus sp., Filinia sp, and Keratella tropica, were the most abundant and persistent, while Thermocyclops decipiens and Mesocyclops aequatorialis were the most abundant and persistent copepods. The biovolume of the copepod species were the highest, while that of the rotifers was the lowest. According the results of Redundancy Analyses (RDA). T. decipiens and B. calciflorus were correlated positively with conductivity and TDS. The Ecopath model identified 7 functional groups: waterfowl(birds), Nile Tilapia, carnivorous zooplankton, herbivorous zooplankton, phytoplankton, and detritus. The trophic levels of the groups varied from 1.00 for primary producers and detritus to 3.56 for predator birds. The ecosystem maturity indices total primary production/total respiration and Connectance index were 1.19 and 0.555, respectively, showing that the lake's system is at developmental stage according to Odum’s theory of ecosystem development. Generally, this is the first trophic model of Lake Tinshu Abaya that has provided some useful insights into the trophic interaction and functioning of the system. | |
| dc.identifier.uri | https://etd.aau.edu.et/handle/123456789/7270 | |
| dc.language.iso | en_US | |
| dc.publisher | Addis Ababa University | |
| dc.subject | Eco Trophic Modeling | |
| dc.subject | Energy Flows | |
| dc.subject | Food Web | |
| dc.subject | Trophic Interaction | |
| dc.title | Assessment of Water Quality, Phytoplankton, Zooplankton and Trophic Interaction of Lake Tinshu Abaya in Partial Fulfillment of the Requirement for Master of Aquatic Ecosystem and Environmental Management (AEEM) | |
| dc.type | Thesis |