Changes in the burial efficiency and composition of terrestrial organic carbon along the Mackenzie Trough in the Beaufort Sea. (30th September 2022)

• Record Type: Journal Article
• Authors: Kim, Dahae; Kim, Jung-Hyun; Tesi, Tommaso; Kang, Sujin; Nogarotto, Alessio; Park, Kwangkyu; Lee, Dong-Hun; Jin, Young Keun; Shin, Kyung-Hoon; Nam, Seung-Il
• Is Part Of: Estuarine, coastal and shelf science. Volume 275(2022)
• Publication Date: 2022-09-30
• Subjects: Beaufort sea -- Mackenzie trough -- Terrestrial organic carbon -- δ13C -- Δ14C -- n-alkanes -- Lignin phenols; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2022.107997
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: In this study, we investigated surface sediments collected along a Mackenzie Trough transect during the R/V Araon expeditions (ARA04C, ARA05C, and ARA08C) in the Beaufort Sea in 2013, 2014, and 2017. We applied various inorganic and organic geochemical tools (major elements, carbon and nitrogen contents, stable carbon and radiocarbon isotope compositions, and molecular biomarkers) in combination with sedimentological measurements (mineral surface area (SA) and grain size) to assess the source and burial characteristics of organic carbon (OC). In general, the sediment mean grain size decreased with water depth whereas the SA increased, resulting in a decrease in the OC loading and the burial efficiency of terrestrial OC. The sedimentary OC was further influenced by the loss of terrestrial OC and replacement with marine OC with increasing water depth. Accordingly, our results suggest that hydrodynamic sorting and degradation of terrestrial OC co-occurred together with the enrichment of marine OC with distance offshore. Such processes controlled the burial and reactivity of terrestrial OC along the Mackenzie Trough transect. Graphical abstract: Image 1 Highlights: The OC loading and burial efficiency of terrestrial OC decreased with distance offshore. The contribution of marine OC to sedimentary OC increased with water depth. Hydrodynamic sorting and degradation of terrestrial OC occurred during transport. The change of the relative contribution of terrestrial and marine OC controlled the composition of sedimentary OC.