Vegetal Undercurrents – Obscured Riverine Dynamics of Plant Debris ...

• Main Authors: Schwab, Melissa S., Hilton, Robert G., Haghipour, Negar, Baronas, J. Jotautas, Eglinton, Timothy I.
• Format: Text
• Language: English
• Published: ETH Zurich 2022
• Subjects: organic carbon; plant biomarker; radiocarbon; Arctic; suspended sediment; undercurrent; Mackenzie river
• Online Access: https://dx.doi.org/10.3929/ethz-b-000541836; http://hdl.handle.net/20.500.11850/541836

Much attention has been focused on fine-grained sediments carried as suspended load in rivers due to their potential to transport, disperse, and preserve organic carbon (OC), while the transfer and fate of OC associated with coarser-grained sediments in fluvial systems have been less extensively studied. Here, sedimentological, geochemical, and biomolecular characteristics of sediments from river depth profiles reveal distinct hydrodynamic behavior for different pools of OC within the Mackenzie River system. Higher radiocarbon (14C) contents, low N/OC ratios, and elevated plant-derived biomarker loadings suggest a systematic transport of submerged vascular plant debris above the active riverbed in large channels both upstream of and within the delta. Subzero temperatures hinder OC degradation promoting the accumulation and waterlogging of plant detritus within the watershed. Once entrained into a channel, sustained flow strength and buoyancy prevent plant debris from settling and keep it suspended in the ... : Journal of Geophysical Research: Biogeosciences, 127 (3) ...