Thermal tolerance and cadmium susceptibility of amphipods endemic to Lake Baikal

Abstract

Lake Baikal is affected by global change and regional human activities. The effects of rising temperature and pollution on the unique endemic littoral amphipod fauna of Lake Baikal are unresolved yet. This thesis provides insights into physiological processes determining thermal tolerance and cadmium (Cd) susceptibility in two littoral amphipod species (Eulimnogammarus verrucosus and Eulimnogammarus cyaneus) compared to the related gammarid Gammarus lacustris, which is ubiquitously spread in the Holarctic. Thermal constraints on the oxygen supply system in E. verrucosus, E. cyaneus and G. lacustris may shape the upper temperature limits to the thermal habitats of the species, in line with the theories of allometry of thermal tolerance and systemic to molecular hierarchy of thermal tolerance. Lethal concentrations of Cd were much lower for E. cyaneus and G. lacustris than for E. verrucosus. However, E. verrucosus showed metabolic depression when exposed to Cd concentrations far below lethal ones. These findings underscore the necessity of water management strategies strictly avoiding chemical contamination of Lake Baikal waters.