Using lignin biomarkers and 14C, of both river DOC and POC, and permafrost soils, to characterize the impacts of climate warming and permafrost degradation on the organic carbon budget of the Hudson Bay, Canada

Abstract

This study looks at characterizing the terrigenous OC sources, like permafrost, of POC and DOC through 17 rivers and six soils of the Hudson Bay (HB) using lignin biomarkers, and Δ14C. Our findings show the dominance of the OC flux (89%) from the southwest Hudson Bay Rivers, especially from DOC (93%), shedding light on the sources and fate of OC in HB sediments. With warming, organic cryosols, with high OC content in the Cz horizon, have the potential to release as much as 1.5 gOC/m2 for every cm increase in active layer depth. The [Ad/Al] ratios, when combined with 14C ages of DOM, show that older SOC is being released in some rivers and is fresher than expected due to its preservation within permafrost. S/V and C/V ratios, are well correlated to latitude in DOM, reflecting the vegetation in their drainage basins and can be used to indicate OC sources.