дек 12, 2009 | 09:12

Ostroumov S. A., Kolesnikov M. P. Biocatalysis of Matter Transfer in a Microcosm Is Inhibited by a Contaminant: Effects of a Surfactant on Limnea stagnalis. - Doklady Biological Sciences, 2000, 373: 397–399. Translated from Doklady Akademii Nauk, 2000, Vol. 373, No. 2, pp. 278–280. Original Russian Text Copyright © 2000 by Ostroumov, Kolesnikov. By excreting some massive amount of organic matter in the form of pellets, the gastropod mollusks drive the transfer of organic matter and contribute to the biogeochemical flows of chemical elements in aquatic ecosystems. For the first time, the quantitative assessment of the biogeochemical flows was made. Also, for the first time, it was discovered that a synthetic chemical may inhibit those flows. The pellet excretion by the gastropods Lymnaea stagnalis feeding on the phytomass of macrophytes (such as Nuphar lutea) was 4–7 mg dry weight per 1 gram wet weight of the mollusks per 72 h. Pellet sedimentation contributes to the vertical transfer of chemical elements in the ecosystem. The pellet composition depended on the species of the plants eaten by the mollusks. When the gastropods L. stagnalis feed on N. lutea, the pellets contain, in addition to organic and inorganic carbon, nitrogen (N, 2.3–2.9%), phosphorus (P, 0.4–0.5%), and silicium (silicon) (Si, 1.1–1.9%). The relative content of Si was 30% higher than in the food phytomass. The synthetic surfactant tetradecyltrimethylammonium bromide (TDTMA, 2 mg/L) inhibited the feeding rate of the mollusks and pellet production, their accumulation at the bottom of microcosms, and the matter transfer connected with this. The data obtained demonstrated a new aspect of the ecological hazard due to environmental pollution with TDTMA and other quaternary ammonium compounds at sublethal concentrations. According to the author’s opinion, other contaminants may also suppress pellet production, their accumulation at the bottom, and the matter transfer associated with that. http://sites.google.com/site/2000dbs373p397biocatallstag/; http://scipeople.ru/users/2943391/