The deposition of terrestrial-derived permafrost particulate organic carbon (POC) has been recorded in major Arctic river deltas. However, associated transport pathways of permafrost POC from the watershed to the coast have not been well constrained. Here we utilized a combination of ramped pyrolysis-oxidation radiocarbon analysis (RPO 14C) along with lignin biomarkers, to track the linkages between soils and river and delta sediments. Surface and deep soils showed distinct RPO thermographs which may be related to degradation and organo-mineral interaction. Soil material in the bed load of the river channel was mostly derived from deep old permafrost. Both surface and deep soils were transported and deposited to the coast. Hydrodynamic sorting and barrier island protection played important roles in terrestrial-derived permafrost POC deposition near the coast. On a large scale, ice processes (e.g., ice gauging and strudel scour) and ocean currents controlled the transport and distribution of permafrost POC on the Beaufort Shelf.
Bibliographical noteFunding Information:
This research was partially supported by funding from the National Science Foundation (NSF EAGER Grant ARC-0935336 and NSF Grants OPP-80937700 and ARC-1023623). The Jon and Beverly Thompson Endowed Chair of Geological Sciences to T. S. Bianchi also provided funding for this project. Special thanks to Destiny Reese for assistance in ramped pyrolysis analysis. All data used in this manuscript are presented in tables and supporting information file. Finally, we thank the two anonymous reviewers for their insightful comments to make this manuscript much improved.
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- Colville River
- carbon cycling