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LIMNOLOGICAL OBSERVATIONS ON LAKE KARIBA DURING 1967 WITH EMPHASIS ON SOME SPECIAL FEATURES 1
Author(s) -
Begg G. W.
Publication year - 1970
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1970.15.5.0776
Subject(s) - hypolimnion , alkalinity , thermocline , chemocline , estuary , hydrology (agriculture) , environmental science , oceanography , structural basin , drainage basin , limnology , geology , anoxic waters , ecology , eutrophication , geography , geomorphology , chemistry , geotechnical engineering , cartography , organic chemistry , nutrient , biology
Results of limnological recordings made during 1967 on Lake Kariba are described. Kariba is monomictic, mesotrophic, and has five defined basins, each of which exhibits its own individuality. The two upstream basins are riverine; they are flushed out in May by the Zambezi River floods and thereby assume turnover characteristics earlier than the other three basins, which are truly lacustrine with temperature‐induced turnover. Great amplitude of variation in water chemistry exists relating to the basin locality, biotope (river, estuary, cleared area, open water), time of year (turnover winter/summer), and depth. Generally, values of dissolved oxygen, conductivity, alkalinity, and pH fall from surface to bottom. When H 2 S is present, alkalinity and conductivity values increase. A chemocline follows the profile of the thermocline. Occasionally density currents occur at depth, particularly after the first seasonal floods. Transparency decreases toward the head of the lake and in all areas decreases after turnover. The source of H 2 S is the Salvinia‐infested rivers. Dissolved oxygen in the hypolimnion is depleted 4 to 5 months after turnover. The hydrobiological effects of Salvinia are discussed, and the influence of the bottom topography is described.