Ref ID : 7096
Hanazato Takayuki, Hayashi Hidetake, Ichikawa Tadafumi, and Watanabe Yasunori; Dynamics of Zooplankton Community in Enclosures of Different Types in a Shallow Eutrophic Lake. Jap.J.Limnol. 50(1):25-37, 1989
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Changes in abundance and species composition to the zooplankton community in enclosures of different types in Lake Suwa were investigated and compared. Zooplankton abundance was consistently higher in tube-type enclosures (5 m x 5 m x 4.2 m), which were open to the bottom sediment, than in bag-type enclosures (5 m x 5 m x 3 m), which had bottom sheets. In the latter enclosures, zooplankton abundance gradually decreased during the experimental period. Zooplankton community structure in the tube-type enclosure changed in a similar way to that in open lake water for eight months. Therefore, an enclosure of this type was considered to be suitable for maintaining an example of the lake ecosystem over a long period. The phenomenon of a decrease in zooplankton abundance in the bag-type enclosure did not apply to the small bag enclosure (1 m x 1 m x 1 m), in which zooplankton had high productivity and a littoral species, Chydorus sphaericus, predominated. This species was not found in the central zone of the large enclosures (in both the bag and tube types). The dominance of C. sphaericus in the small bag enclosure was probably due to wall effects.