Ecotoxicological studies with the freshwater rotifer Brachionus calyciflorus

Abstract

The use of the freshwater rotifer Brachionus calyciflorus as a test organism for ecotoxicological studies was examined . Changes in the feeding-, swimming behavior-and demographic characteristics of the rotifers exposed to increasing concentrations of copper (Cu) were studied and the relationships between the different test parameters and their ecological relevance evaluated .Relatively simple short-term bioassay methods were developed to measure the swimming activity (2 hours) and the filtration (5 hours) rate . Life-table experiments were performed to asses the long-term effects of Cu on the rotifers . Significant reductions in the filtration rate, the swimming activity and the demographic parameter r were observed at 20, 12 and 5 ig 1 -1 of Cu, respectively. The implications and the possible ecotoxicological applications of the results are discussed . 21

Effect of Sublethal Exposure to Chlordecone on Life History Characteristics of Freshwater Rotifer Brachionus calyciflorus Pallas

“…The arrow indicates the age at which the rotifers became reproductive Table 2 Intrinsic rate of population increase (r m ), net reproductive rate (R 0 ), generation time (T) and life expectancy at hatching (e 0 ) of Brachionus calyciflorus exposed to sublethal concentrations of chlordecone (mean ± standard error) way ANOVA). Compared with the blank control agent, acetone at 0.5& had no effect on the rotifers, but chlordecone at 0.5 to 50 lg/L increased the net reproduction rate (p < 0.05), which was identical to its effect on the lifetime egg production (Table 1), but contrary to the effects of pentachloro-phenol, 3,4-dichloroaniline, DDT, endosulfan, Cu, lindane, methylparathion, thiophanatemethyl, glyphosate, or deltamethrin on the net reproduction rates of B. calyciflorus and Brachionus patulus Ferrandez-Casalderrey et al, 1991Ferrando et al, 1993;Halbach, 1984;Janssen et al, 1993Janssen et al, , 1994Kooij-man and Metz, 1984;Rao and Sarma, 1986;Xi and Hu, 2003;Xu et al, 2005). In addition, chlordecone at 0.5 and 50 lg/L prolonged the generation time (p < 0.01), which contributed to the prolonged duration of the juvenile period (Table 1).…”

“…1), we calculated the intrinsic rate of population increase, the net reproductive rate, the generation time, and the life expectancy at hatching of the rotifers (Table 2). In contrast to the effects of all the other tested compounds such as pentachloro-phenol, 3,4-dichloroaniline, DDT, endosulfan, Cu, lindane, methylparathion, thiophanatemethyl, glyphosate, deltamethrin Ferrandez-Casalderrey et al, 1991Ferrando et al, 1993;Halbach, 1984;Janssen et al, 1993Janssen et al, , 1994Kooijman and Metz, 1984;Rao and Sarma, 1986;Xi and Hu, 2003;Xu et al, 2005), chlordecone did not significantly influence the intrinsic rate of population increase or the life expectancy at hatching of the rotifers (p > 0.05, one-way ANOVA).…”

The role of biomarkers in environmental assessment (5). Invertebrate populations and communities

“…Contaminants sometimes stimulate (O'Brien et al 1985), but more frequently decrease, the feeding activity of invertebrates. Reduction in feeding was observed in target and non-target insects (Hirata andSogawa 1976, Woin andLarsson 1987), in crustaceans (Atema et al 1979, Day and Kaushik 1987, Jones et al 1991 and in other invertebrates such as corals (Loya and Rinkevich 1980), mussels (Widdows and Donkin 1991) or rotifers (Janssen et aL 1993). The repellent properties of some chemicals such as pyrethroids may also decrease food intake and subsequent growth rate in non-target (Gerig 1981) and target (Bernard and Lagadic 1993) insect species.…”

Ecotoxicological studies with the freshwater rotifer Brachionus calyciflorus II. An assessment of the chronic toxicity of lindane and 3,4-dichloroaniline using life tables

“…Constant exposure of these organisms to fenvalerate over their entire life cycle may reduce their overall fitness and thus reproduction . Effects of copper on the feeding behav-3 9 for of B. calyc forus is reported upon in this volume (Janssen et al, 1993).…”