ISSN:
1573-5117
Keywords:
tropical zooplankton
;
species composition
;
seasonal abundance
;
Ethiopian Rift Valley lakes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The composition and annual cycle of the zooplankton of two Ethiopian Rift Valley soda lakes is described. Lake Langano has a conductivity of 1 400 to 1800 µS cm−1 and a permanent mineral turbidity. Lake Abiata is more concentrated (conductivity 19 000 to 23 000 µS cm−1) and more alkaline but less turbid; it is characterised by dense phytoplankton blooms, mainly cyanophytes. The zooplankton assemblage is typically tropical, with relatively few species of Cladocera and Copepoda. There was a marked difference in zooplankton between the two lakes, Lake Abiata showing much higher concentrations and greater wet season/ dry season differences. The species composition was also different. Lake Abiata lacked Cladocera, and calanoid copepods occurred only during the wet season with lower conductivities. These two phenomena were attributed to high sodium bicarbonate concentration and to dense cyanophyte blooms. Eleven species of rotifers occurred in Lake Abiata, including six Brachionus spp. but B. rubens was the only rotifer found in Lake Langano. The seasonal variation of the zooplankton is discussed in relation to seasonal fluctuations in conductivity and Chl a concentration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00026599
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