On studying the hazards of pollution of the biosphere: Effects of sodium dodecylsulfate (SDS) on planktonic filter-feeders

Abstract

Many species of planktonic and benthic invertebrates are active filter-feeders. The filtration activity of aquatic organisms is of great importance for the functioning of ecosystems [1‐3]. It was shown earlier that surfactant sodium dodecylsulfate (SDS) inhibits the filtration activity of Mytilus edulis, M. galloprovincialis , and some other aquatic filter-feeders [4‐15], which is manifested in a decreased removal of suspensions from water by these organisms. Similarly to other water pollutants, surfactants have a strong anthropogenic impact on ecosystems [14]. The goal of this study was to test whether SDS has an inhibitory effect on the ability of planktonic filterfeeders Daphnia magna to remove phytoplankton from water during their filtration activity. Experiments were performed with five-day-old D. magna approximately 1 mm in size at an age of five days. Before the beginning of the experiment, daphnia were kept under laboratory conditions in vessels and fed with phytoplankton (green algae Scenedesmus quadricauda (Turp.) Breb.) at a low concentration (at most 50 thousand cells/ml). At the beginning of the experiment, S. quadricauda cells were added at a higher concentration (400 thousand cells/ml). In the control variant, daphnia were incubated in an SDS-free medium. In the experimental variants, the incubation medium contained SDS at preliminarily selected concentrations (0.1, 0.5, 1, 5, and 10 mg/l). The concentration of S. quadricauda cells was determined in a Nageotte counting chamber at a depth of 0.5 mm 3, 6, 9, 12, and 24 h after the beginning of the experiment. Each vessel contained 50 ml of water medium and 25 daphnia. Incubation was performed at 24 ± 1.5°e . Each variant was performed in duplicate. The rate of food consumption (algae removal from water) by one daphnia ( R ) was calculated by conventional formula