Ref ID : 2355
Wilfried Schonborn; [Populationsdynamik und Produktion der Testaceen (Protozoa: Rhizopoda) in der Saale] (Population Dynamics and Production of Testacea (Protozoa: Rhizopoda) in the River Saale). Zool.Jb.Syst. 108:301-313, 1981
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In the river Saale near the village Rothenstein (GDR, Thuringia), the density, biomass, annual production, mortality, number of generations and the annual consumption were investigated. The obtained data submitted a carbon-balance of the Testacea-association for 1979. The density, biomass and production were estimated in a 14-days period on slides, which were exposed in the river. The recording of food took place in the laboratory. The dominant species ate essentially diatoms. Some food-diatoms were determined. The net production was (1979) 5x10E6 i/m2 a (=1338 mg/m2 a =67 mgC/m2 a =2.6 kJ), the average P/B (year) amounted to 16.8. The association of Testacea consumed 2444 mg diatoms/m2 a (=122 mgC/m2 a). Other components of food (Bacteria, Chlorophyceae) were disregarded. With the help of informations from the literature, assimilation (85 mgC/m2 a) and respiration (21%) were calculated. There was no seasonal dependence in the abundance of Testacea on slides. The abundance is controlled by density. In a 10 to 14-day period many individuals were produced (~1000 i/slide). The generation times reached from 1 to 8.5 days. By the density-maximum, the cell divisions come to an end, and many individuals live 50 and more days. The gradual increase of mortality reduces the density. High abundance was frequently correlated with low production. A production-mortality-balance was calculated. The average daily production was 25x10E3 i/m2 day =6.8 mg/m2 day. Centropyxis aculeata, the dominant species, shows 60 and Trinema lineare only 11 annual generations on the slides. In comparison with the ciliated protozoa, the Testacea have a low part in the transport of material and energy in the river-ecosystem.