Understanding fitness-related effects of dispersed oil on Calanus finmarchicus

The planktonic copepod Calanus finmarchicus is the dominating species in the Norwegian Sea and Barents Sea in terms of biomass, and because of its central position in the food web and large lipid content it is by far the most important source of energy fo r a number of fish species. This crucial ecological position is the basis for a general concern regarding potential oil-induced effects on copepod populations and on potential introduction of lipophilic oil compounds into the sub-Arctic and Arctic pelagic food web. This project congregates unique knowledge related to C. finmarchicus. Using a combination of an established culture of C. finmarchicus, custom-made equipment for assessing developmental and reproductive effects of dispersed oil on this species and state of the art screening tools for molecular profiling, this project will generate links between oil uptake, molecular and fitness-related effects, and help predicting population-level impact. Experiments will be focused on effects of dispersed oil on a few but vital physiological processes: Reversible and irreversible narcosis, lipid accumulation, reproduction and moulting. Deeper understanding of copepod physiology will be achieved and the effects of dispersed oil, generated in an environmentally realistic manner for exposure, will be better understood. The molecular profiling approach will be used to determine a no observed molecular effect concentration (NOMEC) for dispersed oil. This approach will be sensitive, however, in contrast to the trad itional predicted no effect concentration (PNEC) approach based on acute toxicity measures and introduction of uncertainty factors, be more scientifically based and thereby more relevant for determination of environmental risk. Profiling will also reveal molecular trends which may be assessed in wild copepod populations as a diagnostic tool for population health.