OPENAIRE OpenAire Datacite HAL INRAE Bielefeld Academic Search Engine (BASE) HAL-IRD Crossref Dépôt Institutionel de l’Université catholique de Louvain et de l’Université Saint-Louis Research Collection Vrije Universiteit Amsterdam (VU Amsterdam) – Research Portal Geophysical Research Letters Open Access 2022-11-01 2022-11-16 2022-12-21 Abstract<p>On￢ﾀﾐ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 ￢ﾈﾼ4,000ￂﾠyears). Many of the smaller periglacial streams affected by abrupt permafrost thaw transport substantially older POC (up to 32,000ￂﾠyears), 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￢ﾀﾐ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.</p particulate organic carbon 0301 basic medicine 570 glacier 550 [SDE.MCG]Environmental Sciences/Global Changes stream Greenland 15. Life on land 01 natural sciences [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment [SDE.MCG] Environmental Sciences/Global Changes 03 medical and health sciences 13. Climate action radiocarbon SDG 14 - Life Below Water 14. Life underwater [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment permafrost 0105 earth and related environmental sciences L. Bröder, C. Hirst, S. Opfergelt, M. Thomas, J. E. Vonk, N. Haghipour, T. I. Eglinton, J. Fouché, 2022-11-03 journalpaper Abstract<p>On￢ﾀﾐ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 ￢ﾈﾼ4,000ￂﾠyears). Many of the smaller periglacial streams affected by abrupt permafrost thaw transport substantially older POC (up to 32,000ￂﾠyears), 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￢ﾀﾐ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.</p Contrasting Export of Particulate Organic Carbon From Greenlandic Glacial and Nonglacial Streams 10.1029/2022gl101210 https://doi.org/10.1029/2022gl101210 676982