High temperature tolerance and heat hardening ability in Enchytraeus albidus Henle, 1837 (Oligochaeta) show no interaction with lipophilic organic pollutants

Abstract

High temperature stress poses various direct challenges for organisms on earth, but also indirectly affects the simultaneous tolerance to other stress factors. In this study we examined the heat tolerance, heat hardening ability and possible interactions between chemical stress and elevated temperatures in the enchytraeid Enchytraeus albidus. Specimens of E. albidus were exposed to chemicals and high temperature stress separately, after which they were exposed to a combination of the two stressors to test for a possible interaction. The chemicals used in this study were 4-nonylphenol and phenanthrene. Both of these chemicals reach the environment as a consequence of anthropogenic activities, and both have the potential to interact with elevated temperatures through effects on the cell membrane. We carried out dose response experiments, including concentrations of the chemicals and high temperatures, having a significant negative effect on survival, however there was no interaction between the two types of stressors. Additionally we found that heat hardening improved survival significantly, but none of the chemicals had an effect on E. albidus’ ability to heat harden. Thus, we found no evidence for the hypothesized negative interaction between increasing temperature and pollution with the chemicals used here.