Ethanol extends lifespan of the rotifer Brachionus plicatilis

Abstract

Despite the increasing environmental concern about the emission of ethanol from ethanol-blended fuels, the aquatic toxicity of ethanol has not been well investigated especially at low concentrations. In this study, we aimed to investigate the effects of 0.1% ethanol on life history parameters and population dynamics of the rotifer Brachionus plicatilis by a series of culture experiments. Rotifers exposed to 0.1% ethanol lived about 20% longer and the first egg-bearing individual appeared about 30 min earlier in the ethanol-exposed group than the control group. The lifetime fecundity was approximately 1.3-fold higher in the ethanol-exposed group than the control group, but the difference was not statistically significant. Ethanol exposure also increased survival time under 0.5 mM hydrogen peroxide. Furthermore, in the batch culture experiment, the maximum population density of ethanol-exposed groups was 1.7 times higher than that of control groups. Overall, these life history alterations were similar to those in glycerol-treated rotifers previously reported, suggesting a common mechanistic basis. Identification of the mechanism of ethanol action will enable future evaluation of effects of increased ethanol release on the organisms in the aquatic environment.