The Changing Arctic Ocean Seafloor (ChAOS) - how changing sea ice conditions impact biological communities, biogeochemical processes and ecosystems

ChAOS will quantify the effect of changing sea ice cover on organic matter quality, benthic biodiversity, biological transformations of carbon and nutrient pools, and resulting ecosystem function at the Arctic Ocean seafloor. We will achieve this by determining the amount, source, and bioavailability of organic matter (OM) and associated nutrients exported to the Arctic seafloor; its consumption, transformation, and cycling through the benthic food chain; and its eventual burial or recycling back into the water column. We will study these coupled biological and biogeochemical processes by combining (i) a detailed study of representative Arctic shelf sea habitats that intersect the ice edge, with (ii) broad-scale in situ validation studies and shipboard experiments, (iii) manipulative laboratory experiments that will identify causal relationships and mechanisms, (iv) analyses of highly spatially and temporally resolved data obtained by the Canadian, Norwegian and German Arctic programmes to establish generality, and (v) we will integrate new understanding of controls and effects on biodiversity, biogeochemical pathways and nutrient cycles into modelling approaches to explore how changes in Arctic sea ice alter ecosystems at regional scales.
We will focus on parts of the Arctic Ocean where drastic changes in sea ice cover are the main environmental control, e.g., the Barents Sea. Common fieldwork campaigns will form the core of our research activity. Although our preferred focal region is a N-S transect along 30 degree East in the Barents Sea where ice expansion and retreat are well known and safely accessible, we will also use additional cruises to locations that share similar sediment and water conditions in Norway, retrieving key species for extended laboratory experiments that consider future environmental forcing. Importantly, the design of our campaign is not site specific, allowing our approach to be applied in other areas that share similar regional characteristics. This flexibility maximizes the scope for coordinated activities between all programme consortia (pelagic or benthic) should other areas of the Arctic shelf be preferable once all responses to the Announcement of Opportunity have been evaluated.
In support of our field campaign, and informed by the analysis of field samples and data obtained by our international partners (in Norway, Canada, USA, Italy, Poland and Germany), we will conduct a range of well-constrained laboratory experiments, exposing incubated natural sediment to environmental conditions that are most likely to vary in response to the changing sea ice cover, and analysing the response of biology and biogeochemistry to these induced changes in present versus future environments (e.g., ocean acidification, warming). We will use existing complementary data sets provided by international project partners to achieve a wider spatial and temporal coverage of different parts of the Arctic Ocean. The unique combination of expertise (microbiologists, geochemists, ecologists, modellers) and facilities across eight leading UK research institutions will allow us to make new links between the quantity and quality of exported OM as a food source for benthic ecosystems, the response of the biodiversity and ecosystem functioning across the full spectrum of benthic organisms, and the effects on the partitioning of carbon and nutrients between recycled and buried pools. To link the benthic sub-system to the Arctic Ocean as a whole, we will establish close links with complementary projects studying biogeochemical processes in the water column, benthic environment (and their interactions) and across the land-ocean transition. This will provide the combined data sets and process understanding, as well as novel, numerically efficient upscaling tools, required to develop predictive models (e.g., MEDUSA) that allow for a quantitative inclusion seafloor into environmental predictions of the changing Arctic Ocean.

ChAOS has the potential to generate impact, beyond the academic community, that will benefit a number of groups or organisations:

a) Community level: Indigenous people, local councils, regulatory bodies and committees will benefit from a greater understanding of the Arctic benthic environment, which is key for the sustainable and multiple use of the seafloor, for example as fishing ground.

b) National level: We will communicate with DEFRA and CEFAS to ensure our project outcomes directly inform political decision making in the UK towards economic exploitation and environmental protection of the Arctic, addressing issues highlighted in the UK government Arctic Policy Framework (2013) and the Report of the House of Lords Select Committee on the Arctic (2015). Communicating and sharing these insights with collaborating scientists in nations neighbouring the Arctic Ocean will strongly increase the visibility of high quality and integrated Arctic research in the UK. In this context, we will also engage with national organisations within the Arctic countries, including the Arctic Monitoring and Assessment Programme (AMAP, a working group of the Arctic Council); Protection of the Arctic Marine Environment (PAME); and MAREANO, the institute for seafloor mapping.

c) Commercial and Industrial sector: A detailed understanding of the benthic-pelagic coupling in the Barents Sea may provide crucial insights into the present and future potential for sustainable and multiple use of the benthic environment, which will be relevant to fisheries, renewables, power generation, and oil and gas. We will forge links with official bodies both in the UK, such as the Renewable Energy Association, and in Arctic nations, such as working groups of the Arctic Council and the Norwegain Oil and Gas Directorate. Our insights into the benthic environment of the Arctic Ocean and its links to higher trophic levels, including economically relevant fish stocks, will provide important baseline information regarding the most sensitive components of Arctic Ocean ecosystems as a whole.

d) Non-government organisations: The World Wildlife Fund, and other NGOs, have explicit interest in the Arctic, its ecological health, and its sustainable development for the benefit of indigenous people. Our research will support the interests of such organisations by highlighting the diversity and the ecosystem functions of benthic ecosystems, but also their sensitivity to climate change, in particular sea ice reductions.