Arctic ecosystem impact assessment of oil in ice under climate change

Climate change cause sea ice to retreat at unprecedented rates opening up large vulnerable Arctic areas and ecosystems for oil and gas exploration and potential new shipping routes. Extracting and transporting oil come with the risk of accidental oil spills. Petroleum activities are therefore strictly regulated, and authorities require risk assessments of new areas before granting licenses. Risk assessments require knowledge of the spatiotemporal distribution of vulnerable marine resources and oil concentrations from spill scenarios driven by high-resolution ocean circulation models to quantify ecosystem impacts. Furthermore, effective communication and cross-disciplinary interaction are required for decision- and policymakers to act upon and implement the scientific findings. Partners in Action has simulated the year 2021 with a high-resolution 2.5 km ocean model including a state-of-the-art ice-model for 24 possible developments of the physical environment that particular year thereby also addressing natural variabilityas communicated in a peer-review publication. These are used to force an oil spill and fate model for oil spill scenarios including 12 different release sites in northern Barents Sea. Oil spill simulations for 6 of these spill sites are combined to a model for early life stages of polar cod including models for ice algae and the zooplankton C. glacialis representing key prey items for polar cod larvae. The results are summarized in two manuscripts that will be submitted this fall. We demonstrate quantitatively that importance of seasonal variations in the ice edge zone and the Polar Front Data for polar cod larval exposure to oil spill. Existing literature has demonstrated the importance of prey availability for survival through winter. Less than half the individuals exposed to oil spill experience good prey conditions during fall. Climate change and the sea ice retreat as well as likely weakening of the Polar Front increase the risk that human impacts in Atlantic Water will extend into areas previously dominated by Polar Waters.

ACTION will develop data-driven mechanistic models based on field and lab experiments to assess cumulative impacts of climate and oil spills on a key Arctic fish species, emphasizing polar cod (Boerogadus saida), relevant to stakeholder policy development. The project will provide decision-makers in government as well as oil industry with more timely and precise information in a relevant format on the risks for marine species when planning for industrial activities, thereby reducing the envelope of uncertainty when developing regulatory measures and operational guidelines. The polar cod is a circum-polar species that plays an essential role in ice-associated food webs, such as in the Barents Sea, linking the lower (i.e. zooplankton) and higher (e.g. other fish, mammals, seabirds) trophic levels. Polar cod has buoyant eggs that are laid under ice and both eggs and larvae are found in high concentrations near the surface following ice melting. Ongoing climate change, with the associated reduction in Arctic sea ice cover, and increased human activity in Arctic waters, combine to pose an increasing threat to polar cod. We will emphasize the understanding of underlying mechanisms for effects so that the outcome is applicable to other species, areas and pollutants. Outcomes include improved and combined models for the environmental parameters, the early life stages, and the fate of oil spills in ice infested areas based on existing field observations and lab experiments in collaboration with international partners. Society benefits from knowledge supporting sustainable management of the marine environment and its resources by resource utilization at optimal levels with societal tolerable footprints. Our development of data-driven models will increase the capacity of quantifying further change in vulnerability to pollutants under climate change. The proposed research will also provide generic knowledge to address other species and other pollutants such as plastics.