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


Retreating and thinning sea ice leads to longer, more extensive open water conditions. While these will prolong the growing season and influence the amount of primary production, they will also change the amount and nature of organic matter reaching the seafloor.

  • How will changes in the surface ocean influence seafloor processes?
  • What are the consequences of this for carbon sequestration in seafloor sediments?
  • How will seafloor biota respond to changes in food quantity and quality?
  • Will there be changes to benthic ecosystem services, for example, the recycling of nutrients to overlying waters?

ChAOS will provide fundamental data and quantify the effects of changing sea ice cover on the resulting ecosystem function on the Arctic seafloor, which will contribute to improving the predictive capacity of the numerical models.

Dr Christian März, University of Leeds, describes the project he leads:

“Our ChAOS project will focus on the bottom of the Arctic Ocean, the seafloor, which is by no means the boring, dark environment it might be perceived as. It is, in fact, a complex ecosystem teeming with life, and it plays an extremely important role in Arctic biodiversity, food webs, the recycling of nutrients back into the overlying water, and the long-term burial of the greenhouse gas carbon dioxide as dead organic material. Our ChAOS team will, without doubt, have the muddiest job on the Programme’s research cruises, but someone needs to do it (and we love it).”

You can follow the ChAOS project on Twitter under @Arctic_Seafloor.

Lead Investigator

  • Dr Christian März

    Lead Investigator, University of Leeds

    Christian März is Associate Professor for Biogeochemistry at the School of Earth and Environment, University of Leeds, and the Lead Investigator of the ChAOS project.

    A geologist by training and marine geochemist by choice, he has over the last seven years studied the behaviour of nutrients and metals in sediments of the Arctic Ocean and the North Pacific.

    Christian’s main focus is on the reconstruction of past environmental conditions from the archive of mud at the seafloor, and on the transformation and recycling processes of chemical elements like iron, manganese, carbon sulphur, phosphorus and silica (to name a few) that are key in biogeochemical processes.

    Within ChAOS, Christian will oversee the sampling and inorganic geochemical analysis of seafloor mud and the water within it – which is much more exciting than it sounds.

    View full profile

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