Seasonal and Spatial Variations of Zooplankton in Relation to Physico-Chemical Variables and Phytoplankton Production in Lake Beseka (Metehara
| dc.contributor.advisor | Mengistou, Seyoum (PhD) | |
| dc.contributor.author | Delelegne, Tesfaye | |
| dc.date.accessioned | 2018-07-11T12:39:21Z | |
| dc.date.accessioned | 2023-11-08T16:33:12Z | |
| dc.date.available | 2018-07-11T12:39:21Z | |
| dc.date.available | 2023-11-08T16:33:12Z | |
| dc.date.issued | 2006-06 | |
| dc.description.abstract | Seasonal and spatial variations of zooplanktoR ·in relation to physico-chemical, variables and phytoplankton production in Lake Beseka were studied from October 2004 to September 2005. The measurements were made on monthly basis. The lake shows temporal variations in temperature (24 -31°G), transparency (0.42-0.63 m) and turbidity (27 -88 NTU). Conductivity (6332 - 7438jJScm,1), total alkalinity (31- 41 meq/l) and pH (9.1-9.5) are higher than those of most other Ethiopian rift valley lakes. The present measurements of phytoplankton production (166 -273 mg O2 m'3h(1) and biomass (7-17 mg chi a m'3) suggest that the lake is not productive as other saline lakes. One factor analysis of variance (A NO VA) and Pearson correlation were used to estimate the level of interaction of physico - chemical and biological factors with zooplankton dynamics. All major zooplankton groups showed temporal variations in abundance, with highest densities during wet period (July to September) and minimum densities during dry period (November to April). The cyclopid copepods were the dominant group and made up almost 64% of the total zooplankton abundance. Rotifers and cladocerans also contributed 19% and 13%, respectively, of the major total zooplankton abundance of the lake. The results of the Pearson correlation demonstrated that population dynamics, of the major zooplankton groups in Lake Beseka appear to be mainly governed by biological and environmental factors, their densities fluctuating along with primary production, phytoplankton biomass and nutrients. Among environmental factors, high temperature and rainfall appear to have promoted a higher density of egg production and total zooplankton number, respectively. Turbidity affected the cladoceran population negatively. Key words: Lake Beseka, zooplankton, temp?ral dynamics, | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/123456789/8088 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Lake Beseka | en_US |
| dc.subject | zooplankton | en_US |
| dc.subject | temporal dynamics | en_US |
| dc.title | Seasonal and Spatial Variations of Zooplankton in Relation to Physico-Chemical Variables and Phytoplankton Production in Lake Beseka (Metehara | en_US |
| dc.type | Thesis | en_US |