Summary
Stressors associated with global climate change and local human activities are affecting marine organisms worldwide. Stressors include changes in temperature, salinity and acidification, in addition to contaminants including metals and hydrocarbons. Near-shore marine assemblages are particularly vulnerable to contamination due to ship fuel spills which often occur close to land, and to run-off of contaminants from terrestrial ecosystems. Climate change will likely increase the vulnerability of marine organisms when coping with contamination events. Climate change in the subantarctic is evident with sea temperatures increasing and salinity decreasing. However, the impacts of both climate change and contamination in this region are poorly understood. Seasonal sea temperature ranges are small in the subantarctic (~2-7°C) compared to in temperate regions (~10-30°C). Therefore any increase in temperature in the subantarctic is expected to have a more profound effect on marine ecosystems. This has been shown in polar regions where small temperature increases cause considerable impacts on organisms which have only small temperature tolerances. This work investigates the effect of multiple stressors including metals, reduced salinity and increased temperature on the behaviour and survival of several common near-shore marine invertebrates from the subantarctic Macquarie Island. Their sensitivity to copper was found to be amplified by increased temperatures and reduced salinities. Concurrent with other regions of the world, this indicates that the combined effect of contamination and climate change stressors will have major impacts on subantarctic marine invertebrates and ecosystems.