Why are Lake Abaya and Lake Chamo so different? A limnological comparison of two neighboring major Ethiopian Rift Valley lakes
- 47 Downloads
Lake Abaya and Lake Chamo are the two largest Ethiopian Rift Valley lakes; they are located close to each other, but have a strikingly different water transparency. We explain key differences in the structure and the functioning of the food web with variation in limnological variables and major pelagic food web compartments within and across both lakes. Data from a detailed comparative investigation of physical and chemical variables and zooplankton community characteristics during the wet and dry season from two consecutive years revealed major differences in key limnological variables between Lake Abaya and Lake Chamo. The most pronounced differences were related to water transparency and the amount of suspended solids in the water column. Lake Abaya is much more turbid, has lower phyto- and zooplankton biomass, and has considerably lower primary production than Lake Chamo. Based on our results, we infer that the profound differences in food web structure between both lakes probably result from differences in sediment load. Finally, our results indicate that conservation programs should focus on reducing sediment inflow from the catchments into the lakes.
KeywordsLake Abaya Lake Chamo Limnology Water transparency Suspended solids Primary production Phytoplankton Zooplankton
This study is part of a collaborative research project “Land and water Research for Sustainable Livelihood in the South Ethiopian Rift Valley” between Arba Minch University in Ethiopia and KU Leuven in Belgium. The authors wish to acknowledge VLIR-OI and VLIR-UOS for the financial support of this research. We sincerely thank Arba Minch University and the KU Leuven Laboratory of Aquatic Ecology, Evolution and Conservation and the Division of Soil and Water Management for facilitating field work and follow-up analyses. The authors gratefully acknowledge Ethiopian Wildlife Conservation Authority and Nechisar National Park for providing us the study license in protected area of the lakes.
- Alemayehu, H. M. & A. J. S. Raju, 2015. Towards sustainable management of Ethiopia’s Lake Chamo biodiversity resources: a geo-spatial supported approach. In Oku, E. E. & K. O. Asubonteng (eds), Harnessing Land and Water Resources for Improved Food Security and Ecosystem Services in Africa. United Nations University Institute for Natural Resources, Accra.Google Scholar
- Baxter, R., 2002. Ethiopian Rift Valley Lakes, Biology of Inland Waters. Backhuys, Leiden.Google Scholar
- Belay, A. & R. Wood, 1982. Limnological aspects of an algal bloom on Lake Chamo in Gamo Goffa administrative region of Ethiopia in 1978. Ethiopian Journal of Science 5: 1–19.Google Scholar
- Belete, A., L. Beccaluva, G. Bianchini, N. Colombani, M. Fazzini, C. Marchina, C. Natali & T. Rango, 2015. Water–rock interaction and lake hydrochemistry in the Main Ethiopian Rift. In Billi, P. (ed.), Landscapes and Landforms of Ethiopia. Springer, Dordrecht: 307–321.Google Scholar
- Bottrell, H., A. Duncan, Z. Gliwicz, E. Grygierek, A. Herzig, A. Hillbricht-Ilkowska, H. Kurasawa, P. Larsson & T. Weglenska, 1976. A review of some problems in zooplankton production studies. Norwegian Journal of Zoology 24: 416–456.Google Scholar
- Boxshall, G. A. & S. H. Halsey, 2004. An Introduction to Copepod Diversity. The Ray Society, London.Google Scholar
- Flössner, D., 2000. Die Haplopoda und Cladocera Mitteleuropas. Backhuys Publishers, Leiden.Google Scholar
- Gebremariam, B., 2007. Basin Scale Sedimentary and Water Quality Responses to External Forcing in Lake Abaya, Southern Ethiopian Rift Valley. Universität Siegen, Siegen.Google Scholar
- Korinek, V., 1999. A guide to the limnetic Cladocera in African inland lakes (Crustacea, Branchiopoda). Stuttgart, Germany.Google Scholar
- Koroleff, F., 1970. Determination of total phosphorus in natural waters by means of persulphate oxidation Interlaboratory report No 3, Vol 3. Le Conseil International pour l’exploration de la mer.Google Scholar
- Lemmens, P., F. E. Teffera, M. Wynants, L. Govaert, S. Deckers, H. Bauer, F. Woldeyes, L. Brendonck, S. Bouillon & L. De Meester, 2017. Intra-and interspecific niche variation as reconstructed from stable isotopes in two ecologically different Ethiopian Rift Valley lakes. Functional Ecology 31(7): 1482–1492.CrossRefGoogle Scholar
- Makin, M., T. Kingham, A. Waddams, C. Birchall & T. Teferra, 1975. Development prospects in the Southern Rift Valley, Ethiopia. Land Resource Study, Land Resources Division, Ministry of Overseas Development, UK (21).Google Scholar
- Oksanen, J., F. Blanchet, R. Kindt, P. Legendre, R. O’Hara, G. Simpson, P. Solymos, M. Stevens & H. Wagner, 2010. Vegan: Community Ecology Package. R package version 1.17-1. R package version: 1.17-6.Google Scholar
- R Development Core Team, 2013. R: a language and environment for statistical computing. In R Foundation for Statistical Computing. http://www.R-project.org/.
- Schröder, R., 1984. An attempt to estimate the fish stock and the sustainable yield of Lake Ziway and lake Abaya, Ethiopian Rift Valley. Archiv für Hydrobiologie Supplementband Monographische Beiträge 69(3): 411–441.Google Scholar
- Schutt, B. & S. Thiemann, 2006. Kulfo River, South-Ethiopia as the regulator of lake level changes in the Lake Abaya-Lake Chamo system. Zentralblatt für Geologie und Paläontologie 1: 129–143.Google Scholar
- Tekelemariam, A. & B. Wenclawiak, Water quality monitoring within Abaya and Chamo drainage basin. In: Lake Abaya Research Symposium Proceedings: 109–116.Google Scholar
- Teklemariam, A. T., 2005. Water Quality Monitoring in Lake Abaya and Lake Chamo Region. University of Siegen, Siegen.Google Scholar