Lake Tanganyika is the largest (~34,000km2)
and oldest (about 10 million years old) of the East African Rift
Valley lakes. It is also the second deepest lake on the planet (1470m
at its deepest point). The lake basin formed as a consequence of
the rifting of the African plate. Many scientists have worked in
recent years using Lake Tanganyika as a model for understanding a
variety of geological processes that shape lakes and their history.
The lakes tectonics, sedimentary geology and paleoecology are
all subjects under active research. The lakes location, long
history, and extensive sedimentary deposits (up to 5km thick in some
places!) have the potential to provide us with a record of African
climate and environmental change extending back through the entire
episode of human evolution.
Over the course of its long and complex
geological history, it has been a hot spot of evolution,
with perhaps 600 species of invertebrates and vertebrates that have
evolved in and are restricted to the lake. Cichlid fish, various
crustacean,s and gastropods make up the bulk of these endemic species.
Today the lake houses incredible species diversity, particularly
along its rocky, steep coastlines, where literally hundreds of species
of fish and invertebrates may be found at a single locality. Over
1500 species of animals and plants have been described from the lake,
making it one of the biologically richest lakes on earth, and new
species are being described each year. Superb visibility in these
near shore rocky habitats (often over 20m) has allowed researchers
to conduct extensive studies on the behavior and ecology of its fish
fauna. Multicellular organisms are restricted to the upper 100-200
meters of the lake however, because the deep parts of the lake are
devoid of oxygen.
Below Lake Tanganyikas oxygen-rich surface
layer lies a zone of nutrient-rich water. This water mass is periodically
mixed by upwelling and turbulence during the windy season into the
surface layer, generating very high algal productivity, which in
turn supports large zooplankton and fish populations. Although the
number of fish species in the open water, pelagic zone of the lake
is small in comparison to the coastal rocky habitats, these species
are periodically very abundant and form the basis of a very important
fishery for the region. Considerable effort by various researchers
has gone into understanding the various linkages between climate,
the upwelling process, productivity, and the abundance of commercially
important fish species.
In recent years Lake Tanganyika, like many
other large lakes of the world, has begun to feel the effects of
a variety of human impacts, including fishing pressures, an increased
rate of sediment accumulation along rocky coasts caused by deforestation
and soil erosion in the lakes watersheds, and climate change.
A major focus of current research on the lake (and an area of particular
interest to several of the Nyanza Project faculty) is understanding
the nature of these impacts and their severity.
As a member of the
Nyanza Project team, you will have the opportunity to get involved
in some very exciting and important research projects. Literally
hundreds of scientific papers have been published on this lake,
many of these by the program faculty. As a good starting
point for understanding the natural history of this fascinating
lake, We recommend the book Lake Tanganyika And
Its Life by George
Coulter (1991, Oxford Univ. Press) or the CD-ROM Biodiversity:
The Great Lakes of Africa by A. Cohen and P. Reinthal (available
through the Nyanza Project office).