Work Experience in Kenya

Transcription

1 Work Experience in Kenya Dr. Steve Omondi Oead alumnus North-South Dialogue Programme 2003 to 2006

2 Activities involved in: Lecturing in Egerton University Public University established through Act of Parliament (1986) Over 15,000 students Focus: Agriculture, Education, Science and technology, Engineering, Health Sciences and Humanities Number of Campuses scattered in Kenya

3 Egerton University-Njoro

4 Teaching interests: Aquatic sciences: Plankton Ecology (Phytoplankton ecology, physiology and taxonomy) Water chemistry (Limnochemistry) Botany: General (Introduction to Botany) Phycology Genetics Mycology

5 Research Interests Limnology of the Rift Valley lakes Arthrospira biomass dynamics Water level fluctuations impact on the ecology of Lake Nakuru Influence of water level fluctuations on Arthrospira food quality Distribution and biomass of bacterioplankton and isolation of physiological groups with industrial potential in Lake Nakuru

6 Research Interests Wastewater treatment and re-use for food production Self-purification abilities of River Njoro through biofilm and periphyton growth

7 Alumni talk topic: Impact of changes in rainfall patterns on the flamingo populations in two Kenyan Rift Valley lakes

8 Rift Valley lakes Courtesy of S.Matagi Major flamingo Lakes in East Africa: L. Bogoria L. Nakuru L. Elmentaita L. Magadi L. Natron Estimated about ½ of world lesser flamingo pop. in E. Africa (L. Nakuru & Bogoria)

9 Characteristics of the saline- alkaline lakes Salinity ( ) >45; mean of seawater ~ 35 ph values around 10 Electrical conductivity (ms cm -1 ) >50; Na + and K + dominant cations, with Ca 2+ and Mg 2+ only in traces Carbonates and bicarbonates major anions Birds` sanctuaries (Lesser Flamingo Phoeniconaias minor) Low plankton diversity dominated by the cyanobacterium Arthrospira fusiformis, few rotifers abd ciliates

10 Flamingo migration in Rift Valley From Burgis and Morris 1987 Known breeding ground L. Natron in Tanzania Big population in L. Nakuru and Bogoria in Kenya May also move to some soda lakes in Ethiopia and Uganda

11 Rift Valley and endorheic lakes formation Tectonic movements and volcanicity Hot climate High evaporation Geological nature of surrounding rocks alkaline springs

12 Importance of L. Nakuru and L. Bogoria National parks=biodiversity conservation Internationally recognised- Ramsar sites UNESCO world heritage sites (L. Nakuru) Tourisms aesthetic value Economically revenue source Culturally-prayer sites (L. Bogoria)

13 Lake Nakuru & Bogoria Importance 1. Wildlife sanctuary & conservation 2. Tourists attraction

14 Lake Nakuru Wildlife attraction

15 Lake Bogoria Geyser

16 Research activity Determine key factors influencing changes in biomass of Arthrospira fusiformis A. fusiformis, main food for the lesser flamingos Phoeniconaias minor Abundance & quality of this food determine lesser flamingo abundance A. fusiformis growth influenced by various abiotic factors, major one being salinity level Salinity level influenced by hydrological patterns and weather characteristics

17 Descriptions of L. Nakuru and Bogoria Lake Nakuru Geographical Position = S 00 o 20 E 36 o 15 Altitude (m. a. s. l) 1,759 Surface area (km 2 ) 40 Mean depth (cm) 110 Rainfall (mm yr -1 ) Lake Bogoria Geographical Position = N 00 o 15 E 36 o 05 Altitude (m. a. s. l) 990 Surface area (km 2 ) 34 Mean depth (cm) 580 Rainfall (mm yr -1 )

18 Lake sampling

19 Sampling exercise Oead alumni talk: 1st Dec 2011

20 Sampling team Oead alumni talk: 1st Dec 2011

21 Samples analysis (Laboratory)

22 Samples and data analysis

23 Rainfall pattern Two rainy seasons March, April and May long rainy seasons with relatively heavy rainfall October November and early December, short rainy season with minimal rainfall received In-between, dry spells

24 Rainfall, salinity and phytoplankton biomass trends trends of phytoplankton biomass, monthly rainfall and salinity (ppt) in lakes Nakuru (top) and Bogoria (bottom) Phytoplankton biomass [mg L -1 ] 07 / / / / / / / / / Monthly rainfall [mm] 60 Salinity [ppt] Phytoplankton biomass [mg L -1 ] 0 Phytoplankton biomass Monthly rainfall Salinity 80 Monthly rainfall [mm] Salinity [ppt] / / / / / / / 09

25 Flamingo feeding Lesser Flamingo beak well adapted for feeding on A. fusiformis Beak has fine sieves to trap algae filaments as it filters water. Flamingo consume 72gm per day (Vareschi, 1982)

26 Optimum growth conditions for A. fusiformis High temperature >25C High ph >9 High nutrients conc (esp. Phosphorus) Salinity range (20 to 50 ppt)

27 Lake Bogoria with high A. fusiformis biomass

28 Oead alumni talk: 1st Dec 2011 Plankton community

29 Lake Nakuru suffers from high fluctuations in water level. Low water level High salinity (>50 g/l) High cond (70mS cm -1 ) Low biodiversity High bacterioplankton abundance Low phytoplankton biomass Flamingos run away High water leves Dilution effect Low salinity (4.4 g/l) Low cond (7.0 ms/cm) High plankton diversity A. fusiformis biomass low Flamingo numbers low Abundance of fish Lots of fish eating birds

30 Lake Nakuru at varied water levels

31 Lake Nakuru Njoro River Mouth (moderate water level = 2m)

32 Drying Lake Nakuru Oead alumni talk: 1st Dec 2011

33 Food quality trends in L. Nakuru and L. Bogoria Dry mass [g L -1 ] Composition of organic matter [%] lipids proteins carbohydrates ash free dry mass ash mass max = Dry mass [g L -1 ] Composition of organic matter [%] lipids proteins carbohydrates ash free dry mass ash mass 07/08 08/08 09/08 10/08 11/08 12/08 01/09 02/09 03/09 04/09 05/09 06/09 07/09 08/09 09/09 10/ /09 07/08 08/08 09/08 10/08 11/08 12/08 01/09 02/09 03/09 04/09 05/09 06/09 07/09 08/09 09/09 10/09 11/09 Sampling time 0.0 Sampling time

34 Lake Nakuru: Pelicans (Piscivorous birds) (moderate water level)

35 Lake Nakuru: High flamingo population

36 Optimum conditions for high flamingo numbers Moderate level of salinity (20-50 g/l) ph level of about 10 High nutrients levels (eutrophic state) High temperatures (27-30) for rapid A. fusiformis productivity High alkalinity conditions (provision of carbon source, ph stability)

37 Reasons for extreme changes in L. Nakuru water level Destruction of the Mau forest Main catchment for L. Nakuru Lack of forest cover, no storage of rain water (sponging effect) Rapid runoff and flash flooding of rivers and lake when it rains (dilution). No continuous river flows to maintain moderate lake levels

38 Reasons for extreme changes in L. Nakuru water level General global climate change Change in rainfall pattern in the region with extreme rainfall and dry conditions High temperatures>high evaporation rates, rapid water loss Nature of Lake Nakuru as a pan, promotes rapid water loss

39 Effects of extreme water level changes Drastic change in chemical state of lake water (rapid dilution or concentration) High water levels: Dilution of ions in the lake Affect biota growth: lower salinity/cond Poor growth of A. fusiformis, the base of productivity in the lake Loss of some organisms: Fish disappears, Pelicans also during very low water levels Dry conditions: High salinity> loss of some biota

40 Lake Bogoria Characteristics Lake is relatively more stable High abundance of A. fusiformis with minimal fluctuations Water level changes are minimal due to its morphometry Physical and chemical characteristics change minimally Flamingo numbers fluctuate minimally

41 Lake Bogoria flamingo abundance Lake Bogoria harbours high pop. No fish in the lake No pelicans found Flamingos always present

42 Acknowledgement Special thanks to the Arthrospira team: Michael Schagerl (Projectleader) Steve Omondi Odour (Kenyan Project leader) Martin grubber (Ph.D candidate) Andrew Yasindi, Alfred Burian (Zooplankton) Mary Kaggwa (Phytoplankton analysis) Pauline Macharia, Benard Simiyu (Technical assistants) Project funded by FWF

43 The End Thank you for your attention