Duties
Fjords represent some of the most efficient natural carbon sinks on Earth. Despite representing <0.1% of the global ocean area, fjords are estimated to bury ~11% of the world’s marine sedimentary organic carbon (OC). Their steep topography, high sedimentation rates, and persistent stratification promote rapid burial of both terrigenous and marine organic carbon, as well as significant contributions from petrogenic carbon derived from eroding sedimentary rocks. Yet, the Canadian Arctic, which contains one of the world’s highest densities of glacially carved fjord systems - stretching Labrador to Ellesmere Island - remains critically understudied. This project will integrate sub-bottom data, sedimentation processes, and geochemical profiles to: quantify OC sequestration across north-eastern Canadian fjords, identify major controls on OC burial (e.g., basin geometry, sedimentology, turbidite carbon pump, degradation rate constants), and model future changes.
Objectives
Obj. 1: Quantify sedimentary organic carbon stocks across a latitudinal transect from Labrador to Ellesmere Island
Obj. 2: Assess mechanisms driving OC deposition and sequestration, including turbidity currents, basin morphology, and sedimentation regimes
Obj. 3: Determine controls on long-term OC burial including remineralization and diagenesis rates
Obj. 4: Develop predictive models of basin-scale OC burial capacity under changing climatic and sedimentary conditions
Methods
This project will integrate marine geology, organic geochemistry, and sedimentology to quantify OC sequestration across north-eastern Canadian fjords. It will leverage sediment cores available at ISMER and the Geological Survey of Canada (GSC), along with existing sub-bottom data.
Marine geology: Mapping of fjord morphology, sediment thickness, turbidity current deposits, and mass-wasting features; identification of depocenters with optimal conditions for long-term OC burial.
Geochemistry: Quantification of %OC by elemental analysis, OC source partitioning by stable and radioactive carbon isotopes as well as Rock-Eval pyrolysis, redox sensitive trace elements analysis by ICP-MS to understand fjord water column redox influence on OC burial.
Sedimentology: Determination of grain size, chronology, water content, and bulk density to estimate carbon mass accumulation rates.
