Ref ID : 698
Pierre Champ and Gif-sur-Yvette; [Population dynamics of a sessile and thermophile rotifer (Sinantherina socialis) in the presence of thermal pollution]. Arch.Hydrobiol. 83(2):213-231, 1978
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The sessile, colonial rotifer Sinantherina socialis (Linnaeus) has been found in great numbers in the river Loire every summer for some years. Population dynamics during the year was investigated by sampling with artifical substrata. The data collected in rearing showed that this species can grow between 18 and 34 degrees C, with a maximum birth rate at 28 degrees C. In the field, the birth rates were estimated with Edmondson's method (1960) using the mean number of eggs per female in the samples. In summer they decrease when the temperature and the population density increase: they are likely limited by the quantity of available food (Diatoms). In fall, they increase with temperature and population density, the main limiting factor being temperature. Below the heat effluent of the nuclear power plant of Chinon, the season of presence of Sinantherina is longer than upsteam, and population densities are higher. But the secondary productivity, likely limited by the quantity of food, does not reach greater values. Although the thermal pollution lengthens the season when Sinantherina socialis can grow, the exception densities of this rotifer are the consequence of the eutrophication of the river.