OMI-perm
Organo-mineral interactions: a controlling factor of the permafrost-carbon feedback to climate?
Lead
Amplified climate change in the Arctic may trigger complex feedbacks to global climate. Permafrost soils store vast amounts of organic matter that upon thaw is exposed to decomposition, thereby generating greenhouse gases that fuel further global warming. Permafrost thaw is also expected to increase the release of organic matter to aquatic systems (streams, rivers, ponds, lakes, fjords, ocean, …). Here it can either be decomposed further or buried and removed from active carbon cycling. Close associations between organic matter and mineral matrices are thought to hinder decomposition, yet, how this intricate interplay of different mechanisms evolves during transport is still poorly understood.
Objectives
In this project, we investigate the role of organo-mineral associations by measuring sedimentological parameters and determining organic matter composition with isotopes, source-specific molecular markers and degradation proxies. All analyses will be conducted on soil samples from the place of thaw, on suspended particles and sediments along the fluvial release path and the marine near-shore, all collected in the Zackenberg valley, Northeast Greenland, in late summer 2019.
Scientific and Social Context of the Research Project
For this project, all organic matter and mineral analyses will be performed on the same samples using consistent techniques along the entire transect. As such, we aim to breach disciplinary boundaries in two ways: By following the material released from permafrost soils along the flow path to its sedimentary sink, we seek to bring together contrasting perspectives developed by soil and marine scientists, communities that share common analytical tools but rarely work together. Additionally, by focusing on the interactions between permafrost organic matter and the mineral matrices we plan to combine a suite of state-of-the-art techniques integrating biogeochemical analyses to characterize organic matter quality with size fractionation protocols, mineral surface area analyses and X-ray crystallography to assess mineral matrix properties and their organic matter associations. The data resulting from this project will provide important new insights into the potentially unique nature of organo-mineral associations in the high Arctic as well as their role in determining the fraction of permafrost organic matter that is remineralised versus re-buried. This will significantly improve our understanding of one of the key processes in organic matter dynamics, which is of great importance since it directly affects the permafrost-carbon feedback to climate change.
Collaborations
This project is carried out in collaboration with the Vrije Universiteit Amsterdam in the Netherlands, Université Catholique in Louvain-La-Neuve, Belgium and Université de Montpellier in France. We received fieldwork support from the INTERACT program (EU-Horizon2020 framework).