Ostroumov S. A., Walz N., Rusche R. Effect of a cationic amphiphilic compound on rotifers. - Doklady Biological Sciences. 2003 (May). Vol. 390. 252-255, https://www.researchgate.net/file.FileLoader.html?key=def6575c794b111fcc31275e853c2b15; [ISSN 0012-4966 (Print) 1608-3105 (Online)]. Welfare of the biosphere depends on filter-feeders that contribute to making water clean and transparent. Important new facts on the hazard of man-made damage to the beneficial function of rotifers, which are the plankton filter-feeders, were discovered. Paper was published, in which for the first time, it was found that a chemical pollutant inhibits filtration activity of rotifers. As a chemical pollutant, a representative of synthetic surfactants was studied. The study featured an advanced technique that allows precise measurement of the filtration rate on the basis of measuring the rate of removal of algal cells from water by rotifers. The experiment was run in the following system: the two-species culture of rotifers (Brachionus calyciflorus) and algae (Nannochloropsis limnetica; Eustigmatophyceae) was studied in a two-stage turbidostat (temperature 20 °C) as described by Walz et al. (1997) with some modifications. Dilution rate (the higher the filtration activity of rotifers, the higher the dilution rate) was monitored in the turbidostat. As a model of a chemical pollutant, the cationic surfactant tetradecyltrimethylammonium bromide (TDTMA) was added to the water of the turbidostat. On the basis of previous studies (Ostroumov, 2000), the concentration of TDTMA was 0.5 mg/L. Dynamics of the dilution rate before and after addition of the chemical was monitored. The dilution rate decreased after the addition of TDTMA. Also, a comparison of the dilution rate in the experimental turbidostat (with the surfactant) with the control turbidostat (without the chemical) was made. Under conditions of the addition of TDTMA the dilution rate was lower than in the control turbidostat. The lower dilution rate means a lower filtration and grazing activity of the population of the rotifers. The results are in accord with the hypothesis that the cationic surfactant TDTMA can inhibit the filtering activity of populations of rotifers. The results support the conclusions of previous publications, in which analogous effects of surfactants on another major group of filter-feeders (the bottom-dwelling bivalve mollusks) were discovered (Doklady of the Russian Academy of Sciences, 2001, 380, pp. 847-849; 2002, vol. 382, pp.138-141). www.springerlink.com/index/R3126462K122M13T.pdf; DOI10.1023/A:1024417903077; Key issues: cationic amphiphilic substance, rotifers Brachionus calyciflorus, algae Nannochloropsis limnetica, turbidostat, filtration activity, cationic surfactant tetradecyltrimethylammonium bromide TDTMA, grazing activity, filtering activity of populations, filter-feeders, chemical pollution, effects of pollutants, sublethal concentration, trophic interactions, man-made effects, anthropogenic,
2003 (May). Vol. 390. 252-255