| AutorIn | | Name: | Kenechukwu Obumneme Akabueze | 2. Beurteilende(r)| Name: | Univ.Doz. Dr. Michael Schagerl | | Herkunftsbetrieb: | | | Arbeit | | Typ der Arbeit: | Masterarbeit | | Sprache der Arbeit: | Englisch | | Titel der Arbeit in Originalsprache: | IMPACT OF CHANGED WATER LEVEL ON THE PHYSICO-CHEMICAL CHARACTERISTICS AND PLANKTON COMMUNITY OF LAKE NAKURU, KENYA | | Titel der Arbeit in deutsch: | Impact of changed water level on physico-chemical characteristics and plankton community of Lake Nakuru, Kenya | | Titel der Arbeit in englisch: | IMPACT OF CHANGED WATER LEVEL ON THE PHYSICO-CHEMICAL CHARACTERISTICS AND PLANKTON COMMUNITY OF LAKE NAKURU, KENYA | | Publikationsmonat: | 04.2016 | | Seitenanzahl: | 77 | | Online-Katalog der Universitätsbibliothek Bodenkultur | | AC-Nummer: | AC13096504 | | Abstract | | Abstract in Deutsch: | Lake Nakuru, a shallow, endorheic, athalassic saline-alkaline lake, located in Kenya is one of the most unique studied soda lakes of the world. It has experienced a dramatic rise in water level over the past four years, which has been attributed to high rainfall, ground and surface inflows. Due to these water level fluctuations, changes in the physico-chemical variables are most likely. Shifts in salinity level and nutrient concentrations may directly affect the plankton community and biomass, and indirectly the Lesser Flamingos population, an important tourist’s attraction that contributes to economic development of Kenya through tourism. We studied if increase in the water level of the lake has changed the physico-chemical parameters and the plankton community of this lake. The study took four months of field and laboratory work. We found a strong reduction in the salinity level compared to former studies and recorded values between 4.8 – 5.5 ‰. Also the nutrient concentrations were reduced with the increase in water level when compared to previously recorded values from this lake. As a result, the phytoplankton taxa were affected, and the dominant taxa shifted from Cyanobacteria to Chlorophyta and Cryptophyta. The “used–to–be-there” dominant phytoplankton Arthrospira fusiformis was outcompeted by the small, single-celled picoplankton, which were most common during this period of low salinity. A small ecotype of Arthrospira fusiformis was found in the lake, but it contributed little to the phytoplankton biomass. The phytoplankton biomass ranged from 12.6 to 47.7 mgL-1. The dominant zooplankton species changed from rotifers to copepods, with Lovenula africana being the most dominant zooplankton species in the lake. Temperature, bacterial abundance and conductivity were the important variables that significantly contributed in the algal species pattern. Overall, the increase in water level of the lake completely changed the physical, chemical and biological characteristics. | | Abstract in Englisch: | Lake Nakuru, a shallow, endorheic, athalassic saline-alkaline lake, located in Kenya is one of the most unique studied soda lakes of the world. It has experienced a dramatic rise in water level over the past four years, which has been attributed to high rainfall, ground and surface inflows. Due to these water level fluctuations, changes in the physico-chemical variables are most likely. Shifts in salinity level and nutrient concentrations may directly affect the plankton community and biomass, and indirectly the Lesser Flamingos population, an important tourist’s attraction that contributes to economic development of Kenya through tourism. We studied if increase in the water level of the lake has changed the physico-chemical parameters and the plankton community of this lake. The study took four months of field and laboratory work. We found a strong reduction in the salinity level compared to former studies and recorded values between 4.8 – 5.5 ‰. Also the nutrient concentrations were reduced with the increase in water level when compared to previously recorded values from this lake. As a result, the phytoplankton taxa were affected, and the dominant taxa shifted from Cyanobacteria to Chlorophyta and Cryptophyta. The “used–to–be-there” dominant phytoplankton Arthrospira fusiformis was outcompeted by the small, single-celled picoplankton, which were most common during this period of low salinity. A small ecotype of Arthrospira fusiformis was found in the lake, but it contributed little to the phytoplankton biomass. The phytoplankton biomass ranged from 12.6 to 47.7 mgL-1. The dominant zooplankton species changed from rotifers to copepods, with Lovenula africana being the most dominant zooplankton species in the lake. Temperature, bacterial abundance and conductivity were the important variables that significantly contributed in the algal species pattern. Overall, the increase in water level of the lake completely changed the physical, chemical and biological characteristics. | | Schlagworte | | Schlagwörter Deutsch: | Water level fluctuation, salinity, plankton community, Arthrospira fusiformis (ecotype), Lovenula africana, Lesser Flamingos | | Schlagwörter Englisch: | Water level fluctuation, salinity, plankton community, Arthrospira fusiformis (ecotype), Lovenula africana, Lesser Flamingos | | Sonstiges | | Signatur: | D-18459 | | Organisationseinheit, auf der die Arbeit eingereicht wird: | H81200 Institut für Hydrobiologie und Gewässermanagement (IHG) | |
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