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Zooplankton Community Grazing Rates in Some Lakes and a Reservoir in Ethiopia

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dc.contributor.advisor Mengestou Seyoum (PhD)
dc.contributor.author Jebessa Habte
dc.date.accessioned 2018-07-02T08:24:07Z
dc.date.available 2018-07-02T08:24:07Z
dc.date.issued 1994-06
dc.identifier.uri http://etd.aau.edu.et/handle/123456789/5323
dc.description.abstract Zooplankton community grazing rate as % of algae grazed per day was determined in five lakes and one public water-supply reservoir from March, 1993 to October, 1993_ Physical and chemical measurements (Temperature, Secchi depth, alkalin~y, salin~y etc_) were taken at the same time. Radio-labelling and change in chlorophyll A (chl.a.) methods were used. Zooplankton commun~y grazing rates ranging from 0-95% day'l were obtained. In size fractionated community grazing always, the larger size zooplankters showed higher %G.day'1. Increase in ambient density of zooplankton resulted in increased %G.day'l in ali cases except for Lake Bishoftu in which the reverse took place. Two regression models relating %G.day-l to temperature (Temp.). mean zooplankton biomass (SO), total zooplankton biomass (ZB), large size zooplankton biomass (UB) and total chlorophyll a (chl.a.) were tested. Backward deletion procedure resulted in three models which explained 27 - 64% of the total variation in %G.day'l. In both the regression models and the correlation matrices, chl.a. concentration was negatively related to %G.day'1. In the later case, temperature was negatively related to %G.day'l and ali types of zooplankton biomass. The regression coefficients were not significant at 5% significant level. Grazing results are compared with other works in temperate and tropical regions and discussed. en_US
dc.language.iso en en_US
dc.publisher Addis Ababa University en_US
dc.subject Biology en_US
dc.title Zooplankton Community Grazing Rates in Some Lakes and a Reservoir in Ethiopia en_US
dc.type Thesis en_US

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