Advancement of benthic indicators and biomarker-based tools for biomonitoring and risk assessment in the Barents Sea region

Expanding oil and gas (O&G) and shipping activities in the absence of sufficient baseline data on the sensitivity of Arctic marine biota to oil related compounds makes environmental risk assessment for the Arctic challenging. Delayed oil weathering and biodegradation, ecological seasonal variations or a delayed manifestation of toxicity in Arctic marine biota could create differences between the susceptibilities of Arctic and temperate monitoring species in the long term. Such differences may be better defined in estuarine or shallow areas, where the frequent resuspension of sediment and strong affinity of oil for sediment organic matter suggest that a large proportion of oil compounds will be transferred to the seafloor, increasing exposure of benthic organisms. Arctic benthos, and in particular sediment-dwelling organisms, can be applied as relevant and sensitive bioindicators of chemical stress and are important food sources for higher trophic levels. Their intrinsic ecological value calls for the evaluation and validation of oil toxicokinetic parameters in Arctic benthos as part of current oil risk assessment procedures and monitoring programmes. Such knowledge may form an important basis for the selection of relevant Arctic benthic bioindicators of long-term environmental impacts of O&G and shipping activities. The aim of this thesis is to develop a suite of candidate exposure methods, including bioaccumulation and biochemical markers, for the identification of bioindicators of chemical stress derived from O&G and shipping in Arctic coastal benthic systems. The second aim is to propose, based on experiments with temperate species, the avoidance of oil contaminated sediment by Arctic benthic amphipods as an oil risk assessment tool for the Arctic. This work contributes to the development of Arctic benthic bioindicators of the cumulative effects of O&G and shipping activities through the identification of robust PAH exposure metrics in representative benthic species of the Barents Sea region