Contrasting Export of Particulate Organic Carbon From Greenlandic Glacial and Nonglacial Streams

• Published in: Geophysical Research Letters
• Main Authors: Bröder, Lisa, Hirst, Catherine, Opfergelt, Sophie, Thomas, Maxime, Vonk, Jorien, Haghipour, Negar, Eglinton, Timothy Ian, Fouché, Julien
• Other Authors: Geological Institute ETH Zürich, Department of Earth Sciences Swiss Federal Institute of Technology - ETH Zürich (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Earth and Life Institute Louvain-La-Neuve (ELI), Université Catholique de Louvain = Catholic University of Louvain (UCL), Department of Earth Sciences Amsterdam, Vrije Universiteit Amsterdam Amsterdam (VU), Ion Beam Physics ETH Zürich, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: particulate organic carbonGreenlandglacierstreamradiocarbonpermafrost; [SDV]Life Sciences [q-bio]; [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study; Greenland; greenlandic; permafrost; Zackenberg
• Online Access: https://hal.inrae.fr/hal-03900540; https://hal.inrae.fr/hal-03900540/document; https://hal.inrae.fr/hal-03900540/file/Geophysical%20Research%20Letters%20-%202022%20-%20Br%20der%20-%20Contrasting%20Export%20of%20Particulate%20Organic%20Carbon%20From%20Greenlandic%20Glacial.pdf; https://doi.org/10.1029/2022GL101210

International audience On-going shrinkage of Greenland's icecap, permafrost thaw, and changes in precipitation are exposing its landscapes to erosion and remobilization of ancient organic carbon (OC) held in soils and sedimentary rocks. The fate of this OC and potential feedbacks to climate are still unclear. Here, we show that the glacial Zackenberg river (Northeastern Greenland) exports aged particulate OC (POC, uncalibrated radiocarbon ages of similar to 4,000 years). Many of the smaller periglacial streams affected by abrupt permafrost thaw transport substantially older POC (up to 32,000 years), especially with enhanced discharge following intense precipitation. Mineralogical analysis, and density and size fractionation of soils and both glacial and nonglacial river sediments reveal that OC is largely associated with phyllosilicate minerals, suggesting stabilization against microbial processing. Enhanced export of ancient, mineral-associated OC as a consequence of summer rainfall may accelerate translocation of OC from terrestrial to marine environments, but could have limited consequences for climate.