THE EAST AFRICAN GREAT LAKES:
LIMNOLOGY, PALAEOLIMNOLOGY AND BIODIVERSITY
ADVANCES IN GLOBAL CHANGE RESEARCH
VOLUME 12
Editor-in-Chief
Martin Beniston, Institute of Geography, University of Fribourg, Perolles,
Switzerland
Editorial Advisory Board
B. Allen-Diaz, Department ESPM-Ecosystem Sciences, University of California, Berkeley,
CA, U.S.A.
R.S. Bradley, Department of Geosciences, University of Massachusetts, Amherst, MA,
U.S.A.
W. Cramer, Department of Global Change and Natural Systems, Potsdam Institute for Climate Impact Research, Potsdam, Germany.
H.F. Diaz, NOAA/ERL/CDC, Boulder, CO, U.S.A.
S. Erkman, Institute for Communication and Analysis of Science and Technology – ICAST,
Geneva, Switzerland.
M. Lal, Centre for Atmospheric Sciences, Indian Institute of Technology, New Delhi, India.
U. Luterbacher, The Graduate Institute of International Studies, University of Geneva,
Geneva, Switzerland.
I. Noble, CRC for Greenhouse Accounting and Research School of Biological Sciences,
Australian National University, Canberra, Australia.
L. Tessier, Institut Mediterranéen d’Ecologie et Paléoécologie, Marseille, France.
F. Toth, International Institute for Applied Systems Analysis, Laxenburg, Austria
M.M. Verstraete, Space Applications Institute, EC Joint Research Centre, Ispra (VA),
Italy.
The titles published in this series are listed at the end of this volume.
THE EAST AFICAN GREAT LAKES:
LIMNOLOGY, PALAEOLIMNOLOGY
AND BIODIVERSITY
Edited by
Eric O. Odada
and
Daniel O. Olago
Pan African START Secretariat,
Department of Geology,
University of Nairobi, Kenya
KLUWER ACADEMIC PUBLISHERS
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CONTENTS
Introduction
ix
Acknowledgements
xi
Geological and Structural Setting of the East African Lakes
A 300 Million Years History of Rift Lakes in Central and East
Africa: An Updated Broad Review
J.-J. Tiercelin and K.-E. Lezzar
3
Climate Dynamics and Climate Variability in the East African
Lakes Region
Extreme Rainfall Events and Lake Level Changes in East Africa:
Recent Events and Historical Precedents
D. Conway
63
Mesoscale Patterns of Rainfall, Cloudiness and Evaporation Over
the Great Lakes of East Africa
S.E. Nicholson and X. Yin
93
Observations, Evaporation and Preliminary Modelling of OverLake Meteorology on Large African Lakes
P.F. Hamblin, P. Verburg, P. Roebber, H.A. Bootsma and R.E.
Hecky
Development of a Coupled Regional Climate Simulation Model for
the Lake Victoria Basin
Y. Song, F.H.M. Semazzi and L. Xie
121
153
vi
Hydrology and Physical Limnology
A Modelling Approach for Lake Malawi/Nyasa/Niassa: Integrating
Hydrological and Limnological Data
D.C.L. Lam, L. Leon, R. Hecky, H. Bootsma and R.C. McCrimmon
189
Ventilation of Lake Malawi/Nyasa
M.K. Vollmer, R.F. Weiss and H.A. Bootsma
209
Application of Satellite AVHRR to Water Balance, Mixing
Dynamics, and the Chemistry of Lake Edward, East Africa
J.T. Lehman
235
Lake-Groundwater Relationships, Oxygen Isotope Balance and
Climate Sensitivity of the Bishoftu Crater Lakes, Ethiopia
S. Kebede, H. Lamb, R. Telford, M. Leng and M. Umer
261
A Review of Sediment Gas Cycling in Lakes with reference to Lake
Victoria and Sediment Gas Measurements in Lake Tanganyika
D.D. Adams and S.O. Ochola
277
Biodiversity, Food Webs and Fisheries
Redundancy and Ecosystem Stability in the Fluctuating
Environments of Long-Lived Lakes
K. Martens
309
Invasion of Lake Victoria by the Large Bodied Herbivorous
Cladoceran Daphnia Magna
R. Jonna and J.T. Lehman
321
Effects of Climate and Human Activities on the Ecosystem of Lake
Baringo, Kenya
P.A. Aloo
335
Limnological Profiles and their Variability in Lake Tanganyika
P-D. Plisnier
349
Sedimentary Processes, Paleoclimate and Paleoenvironment
Sedimentology and Geochronology of Late Pleistocene and
Holocene Sediments from Northern Lake Malawi
S. L. Barry, M. L. Filippi, M. R. Talbot and T. C. Johnson
369
vii
A 24,000 yr Diatom Record from the Northern Basin of Lake
Malawi
F. Gasse, P. Barker and T.C. Johnson
393
Lake Tanganyika Holocene Record on Variability in Precipitation
in the Malagarasi Catchment Basin
A.N. Muzuka and N. Nyandwi
415
Late Quaternary Sedimentation and Climate in the Lakes Edward
and George Area, Uganda-Congo
T. Lærdal, M. R. Talbot and J.M. Russell
429
Pigment Analysis of Short Cores from the Central Ethiopian Rift
Valley Lakes
M.U. Mohammed, R. Bonnefille and S. Kebede
471
Origin and Isotopic Composition of Aragonite Laminae in an
Ethiopian Crater Lake
H. Lamb, S. Kebede, M. Leng, D. Ricketts, R. Telford and M. Umer
487
Vegetation Changes and their Climatic Implications for the Lake
Victoria Region during the Late Holocene
I. Ssemmanda and A. Vincens
509
Organic Content and X-ray Density of Lacustrine Sediments from
Hausberg Tarn, Mount Kenya
W. Karlén, E. Odada and O. Svanered
525
Human Dimensions: Impacts and Management
Restoring and Protecting the African Great Lake Basin Ecosystems
- Lessons from the North American Great Lakes and the GEF
A. M. Duda
537
Geological Hazards and Anthropogenic Impacts on the Environment
in Malawi: Lesson from a Case Study of Debris Flows in Zomba
J. Mwenelupembe and H-G. Mylius
557
The Human Dimensions Studies on the East African Lake Regions:
A Review
M. M. Opondo
575
INTRODUCTION
The Second International Symposium on the East African Lakes was held from
10-15 January 2000 at Club Makokola on the southern shore of Lake Malawi. The
symposium was organized by the International Decade for the East African Lakes
(IDEAL), a research consortium of African, European and North American scientists
interested in promoting the investigations of African Great Lakes as archives of
environmental and climatic dynamics. Over one hundred African, European and
North American scientists with special expertise in the tropical lakes participated in
the symposium which featured compelling presentations on the limnology,
climatology, palaeoclimatology and biodiversity of the East African Lakes. It is their
papers that comprise this book.
The large lakes of East Africa are important natural resources that are heavily
utilized by their bordering countries for transportation, water supply, fisheries, waste
disposal, recreation and tourism. The lakes are unique in many ways: they are
sensitive to climatic change and their circulation dynamics, water-column chemistry
and biological complexity differ significantly from large lakes at higher latitudes;
they have long, continuous, high resolution records of past climatic change; and they
have rich and diverse populations of endemic organisms. These unique properties
and the significance of the palaeolimnological records demand and attract research
interest from around the world.
IDEAL research is contributing to our understanding of basic limnological
processes in the African Great Lakes and how physical dynamics drive their
biogeochemistry and thus rendering them sensitive, compared to temperate great
lakes, to climatic and anthropogenic change. Recent studies indicate that Lake
Victoria has undergone dramatic shifts in the lake ecosystem caused by the
introduction of the Nile Perch in 1950s and of the water hyacinth during the past five
years. The lake also dried up completely prior to 12,400 years BP. Thus, the
hundreds of species of fish in modern Lake Victoria may have evolved within the last
12,400 years; this is the fastest rate of vertebrate species evolution ever recorded.
Elsewhere in East Africa, high resolution studies of past climate change in Lake
Naivasha, Kenya and in Lake Malawi have shown a distinct Little Ice Age in tropical
Africa. Evidence for the Younger Dryas even in tropical Africa has also been
documented in the sediment record of Lake Albert. More recent studies have
demonstrated that Lake Malawi was at a low stand during the LGM like all the
African lakes in the Northern Hemisphere. This lake was previously known to have
x
been low in the early Holocene and around 35ka but was believed to have been at a
high stand during the LGM.
Lake Malawi and Lake Tanganyika are aquatic island systems of elevated
endemic biodiversity providing extraordinary conditions to study evolutionary
biology. In these lakes we have the unique opportunity to investigate the dynamics of
evolutionary and ecological change. Patterns of speciation, the origin of major
morphological evolution, and the origin of major reorganizations in community
structures can all be investigated in a comparative setting in these two lakes. The
sedimentary record of these lakes offers us an opportunity to resolve both
evolutionary and ecological changes in their biota at time scales of decades,
centuries, millennia, to millions of years. Despite their long histories and geological
similarities, the patterns of diversity and genetic differentiation of the biota differ
dramatically between Lakes Malawi and Tanganyika. Both lakes were colonized by
cichlid fishes, thiarid gastropods and ostracode crustaceans, but these exemplar taxa
currently have contrasting aspects in the two lakes. Approximately 1000 fish species
are estimated to have evolved within the cradle of Lake Malawi, which is
approximately 10 per cent of all freshwater fish species in the world. Despite their
astonishing multitude, these species encompass a rather modest degree of molecular
genetic and morphological change. The fishes in Lake Tanganyika are genetically
and morphologically much more diverse than those in Lake Malawi, yet total only
300 species. In Lake Tanganyika about 240 out of 250 species of prosobranch
gastropods and ostracode crustaceans are unique to that lake, and like the cichlid fish,
form numerous distinct, divergent lineages. The living prosobranch gastropod fauna
of Lake Malawi has undergone only limited differentiation and few if any endemic
ostracodes are reported from this lake.
The papers presented in this book provide a comprehensive coverage of the large
lakes of East African Rift Valley, touching on climate, limnology, palaeoclimatology,
sedimentation processes, biodiversity and management issues of these lakes. The
papers show that high quality, globally relevant research can be, and is being done in
Africa. The call from African researchers is for their international colleagues and the
science funding agencies to move from a position where they see their interactions in
Africa essentially as “capacity building” to one of partnership and “capacity
recognition” with capacitating where necessary and effective. African and developed
world science administrators must work together to sustain the scientific capacity
which has been built in Africa, instead of tacitly allowing it to migrate to Europe and
North America. The world needs it to stay home.
Eric O Odada.
ACKNOWLEDGEMENTS
The Second International Symposium on the East African Lakes on the
limnology, climatology and palaeoclimatology of the East African Lakes was held in
Malawi at Club Makokola on the palm-fringed southern shore of Lake Malawi. The
symposium was sponsored by the John D. and Catherine T. MacArthur Foundation,
The International START Secretariat through NORAD funding for global
environmental change research and capacity building in sub-Saharan Africa, and the
PAGES International Project Office. We are grateful for the generous support that
made the symposium and the publication of this volume possible.
The symposium was organized by IDEAL in collaboration with the University of
Malawi, the Large Lakes Observatory, University of Minnesota, USA and the PanAfrican START Secretariat, University of Nairobi, Kenya. We are particularly
grateful to the Department of Geology at Bunda College University of Malawi for
providing all the logistical support for the symposium. We are also very grateful to
the management of the Club Makokola for providing excellent conference facilities at
this picturesque resort on the southern shore of Lake Malawi.
Tom Johnson of the Large Lakes observatory, University of Minnesota spent
much of him time providing valuable advice to the organizing committee for the
symposium. We also benefited considerably from the advice provided by the IDEAL
Steering Committee. The authors of the articles in this volume are to be commended
for their commitment to research on the African Great Lakes, despite the logistic
challenges that accompany such efforts. We greatly appreciate the efforts of all the
following reviewers, who substantially improved the quality of the papers published
in this book.
Eddie Allison, P. Anadon, Daniel Ariztegui, Mamboudou Ba, Richard Back,
Michael Biryabarema, Gary Bowen, Don Branstrator, Arthur S. Brooks, John
Bullister, Peter Casper, Tesfaye Cherinet, Steven Dadzie, Jean-Pierre Descy, Cynthia
Ebinger, Hubert Gallee, A.T. Grove, Paul Hamblin, Robert Hecky, Karin Holmgren,
Andrew Hudson, Ken Irvine, Emi Ito, Thomas C. Johnson, G. Khroda, Seth Kisia,
Koen Martens, Henry Lamb, Suzanne Levine, Stephen McCord, Sarah Metcalf,
Joseph Mworia-Maitima, Isaac Nyambok, S. Odingo, R. Okoola, Anne-Marie
Oldewage, A.O. Opere, Adrian G. Parker, Ingemar Renberg, Louis Scott, F. Semazzi,
William Smethie Jr., J. Sutcliffe, David Swayne, Michael Talbot, Jean-Jacques
Tiercelin, Dirk Verschuren, Martin Vollmer.