Source of sedimentary organic carbon along a Mackenzie Trough transect in the Canadian Beaufort Sea

Abstract

The Arctic is warming twice as fast as other parts of the Earth. Thus, the release of vast amounts of organic carbon (OC) from the terrestrial permafrost to the Arctic Ocean is expected to be accelerated through several pathways including river discharges. The Mackenzie River, which is the fourth-largest Arctic river in terms of freshwater discharge, but the first in terms of sediment discharge, is thus the most important source of terrestrial freshwater and sediment input to the Beaufort Sea. In this study, we investigated surface sediments collected along a Mackenzie Trough transect during the ARA04C, ARA05C, and ARA08C expeditions of the Korean ice-breaker R/V Araon in the Canadian Beaufort Sea in 2013, 2014, and 2017, respectively. We analyzed the samples for bulk (grain size, major element, TOC, TON, δ13Corg, and △14Corg) and molecular (n -alkanes and sterols) parameters to assess the source of sedimentary OC. Our results provide information on the effect of the recent Arctic warming on the land-ocean terrestrial OC transfer in the Canadian Beaufort Sea.