ChAOS in the Arctic.

by Christian März

The NERC-funded project “The Changing Arctic Ocean Seafloor” (ChAOS) has been going for a year now, and it is one of the most exciting interdisciplinary projects I have ever been a part of! 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 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

• a detailed study of representative Arctic shelf sea habitats that intersect the ice edge, with
• broad-scale in situ validation studies and shipboard experiments,
• manipulative laboratory experiments that will identify causal relationships and mechanisms,
• analyses of highly spatially and temporally resolved data obtained by the Canadian, Norwegian and German Arctic programmes to establish generality, and
• 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 our research on the Barents Sea, a part of the Arctic Ocean where drastic changes in sea ice cover and water mass distribution are the main environmental control. Common fieldwork campaigns will form the core of our research activity. Our 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. 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 that allow for a quantitative inclusion seafloor into environmental predictions of the changing Arctic Ocean.

More information can be found at https://www.changing-arctic-ocean.ac.uk/