Inferences about the modern organic carbon cycle from diagenesis of redox-sensitive elements in Hudson Bay.

• Published in: Journal of Marine Systems
• Main Authors: Kuzyk, Zou Zou A., Macdonald, Robie W., Stern, Gary A., Gobeil, Charles
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2011
• Subjects: Hudson Bay; organic carbon; sediment; redox; trace elements; Arctic; Hudson; Hudson Strait
• Online Access: https://espace.inrs.ca/id/eprint/10635/; https://doi.org/10.1016/j.jmarsys.2010.11.001

The remineralization of organic matter (OM) in Hudson Bay was examined using redox element (Mn, Fe, S, Cd, Re, Mo and U) profiles in six sediment cores. Variation in thickness of surface Mn enrichments and increases in Fe and S in subsurface sediments provide a means to sort sediment cores according to metabolic intensity. The data imply a relatively high flux of labile OM in Hudson Strait, weaker labile OC fluxes in inshore regions of Hudson Bay and weakest fluxes in central Hudson Bay. Enrichments of Cd, U, and Re, which precipitate in reducing sediments, are present at depth in all sediments, whereas Mo enrichments occur only in the more strongly reducing sediments. Highest rates of authigenic element accumulation in the inshore regions generally reflect the higher flux of labile OM inferred from Mn profiles. After accounting for variation in water depth, we find Hudson Bay to be the most oligotrophic among ocean margins for which there are comparable data. Redox element profiles in sediments provide a way to compare and thus possibly monitor change in labile OC forcing over different continental margins, including those in Arctic seas, where other monitoring methods are scarce.