Benthic Carbon Cycling and Storage in Arctic Fjords
What is the motivation?
Marine sediments in Arctic fjords act as dynamic carbon reservoirs, but current biogeochemical models underestimate their role. Limited knowledge of how seafloor characteristics and benthic communities regulate carbon cycling and burial prevents accurate predictions of the climate impacts linked to Greenland Ice Sheet melt and global carbon exchanges.
Why does it matter?
Arctic fjords vary widely—from marine-terminating to land-terminating glacier systems, between different fjords, and over long timescales. Understanding how different forms of carbon are transferred, transformed or stored across these environments is essential to predict where carbon is buried for long periods versus where it is rapidly recycled. Reconstructing past conditions provides insight into how fjords responded to previous environmental changes, strengthening the ability to forecast carbon cycling as ice melt accelerates.
© Ludovic Pascal
Project Focus
Uncertain-Sinks investigates how benthic carbon cycling changes with glacier type (marine-terminating vs land-terminating), latitude, seafloor characteristics and benthic community structure, with particular attention to carbon residence time and burial efficiency. It aims to identify the physical, biological and geochemical factors that control carbon transformation and retention from bottom waters to deep sediments, and to assess how natural disturbances such as landslides or turbidity currents alter carbon storage and remineralisation.
How will it be done?
Working along a transect from fjord heads to deep ocean basins, the project will map the seafloor using acoustic techniques to identify sediment accumulation patterns and natural hazards such as landslides, and to guide sampling locations. Benthic chambers will measure carbon exchanges between sediments and overlying water in natural conditions, while sediment cores up to 9 metres deep will be collected. Laboratory analyses will then document both present and past sedimentary carbon transformations, revealing how carbon processing has changed over centuries to millennia.
© Ludovic Pascal
What will be collected?
After seafloor mapping, samples will be collected from bottom waters to deep sediments. An autonomous benthic chamber will gather bottom-water samples at set time intervals to estimate gas and nutrient exchanges at the sediment–water interface. Sediment cores will provide information on macrobenthic community structure, bioturbation rates and diagenetic processes that influence long-term carbon storage.
Members and partners
- Principal Investigator:
- Ludovic Pascal, Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, Canada
- Other participants:
- Chris Algar (Dalhousie University)
- Rémi Amiraux (CNRS Takuvik, Université Laval)
- Philippe Archambault (Université Laval, CNRS Takuvik)
- Gwenaëlle Chaillou (Institut des sciences de la mer, Université du Québec à Rimouski)
- Hilary Corlett (Memorial University)
- Stephanie Kusch (Institut des sciences de la mer, Université du Québec à Rimouski)
- Patrick Lajeunesse (Université Laval)
- Jean-Carlos Montero-Serrano (Institut des sciences de la mer, Université du Québec à Rimouski)
- André Pellerin (Institut des sciences de la mer, Université du Québec à Rimouski)
- Emilie Saulnier-Talbot (Université Laval)
- Paul Snelgrove (Memorial University)
- Guillaume St-Onge (Institut des sciences de la mer, Université du Québec à Rimouski)
- Partners:
- Bruno Lansard, Université Versailles Saint-Quentin
- Samuel Jaccard, Université de Lausanne
- Pieter van Beek, Université de Toulouse
- Jean-Éric Tremblay, Université Laval