Topsoil organic matter build-up in glacier forelands around the world

Bibliographische Detailangaben
Veröffentlicht in:	Global change biology. - 1999. - 27(2021), 8 vom: 28. Apr., Seite 1662-1677
1. Verfasser:	Khedim, Norine (VerfasserIn)
Weitere Verfasser:	Cécillon, Lauric, Poulenard, Jérôme, Barré, Pierre, Baudin, François, Marta, Silvio, Rabatel, Antoine, Dentant, Cédric, Cauvy-Fraunié, Sophie, Anthelme, Fabien, Gielly, Ludovic, Ambrosini, Roberto, Franzetti, Andrea, Azzoni, Roberto Sergio, Caccianiga, Marco Stefano, Compostella, Chiara, Clague, John, Tielidze, Levan, Messager, Erwan, Choler, Philippe, Ficetola, Gentile Francesco
Format:	Online-Aufsatz
Sprache:	English
Veröffentlicht:	2021
Zugriff auf das übergeordnete Werk:	Global change biology
Schlagworte:	Journal Article carbon stability chronosequence climate sensitivity soil organic matter topsoil development Soil Carbon 7440-44-0 Nitrogen N762921K75

Beschreibung
Zusammenfassung:	© 2020 The Authors. Global Change Biology published by John Wiley & Sons Ltd. Since the last glacial maximum, soil formation related to ice-cover shrinkage has been one major sink of carbon accumulating as soil organic matter (SOM), a phenomenon accelerated by the ongoing global warming. In recently deglacierized forelands, processes of SOM accumulation, including those that control carbon and nitrogen sequestration rates and biogeochemical stability of newly sequestered carbon, remain poorly understood. Here, we investigate the build-up of SOM during the initial stages (up to 410 years) of topsoil development in 10 glacier forelands distributed on four continents. We test whether the net accumulation of SOM on glacier forelands (i) depends on the time since deglacierization and local climatic conditions (temperature and precipitation); (ii) is accompanied by a decrease in its stability and (iii) is mostly due to an increasing contribution of organic matter from plant origin. We measured total SOM concentration (carbon, nitrogen), its relative hydrogen/oxygen enrichment, stable isotopic (13 C, 15 N) and carbon functional groups (C-H, C=O, C=C) compositions, and its distribution in carbon pools of different thermal stability. We show that SOM content increases with time and is faster on forelands experiencing warmer climates. The build-up of SOM pools shows consistent trends across the studied soil chronosequences. During the first decades of soil development, the low amount of SOM is dominated by a thermally stable carbon pool with a small and highly thermolabile pool. The stability of SOM decreases with soil age at all sites, indicating that SOM storage is dominated by the accumulation of labile SOM during the first centuries of soil development, and suggesting plant carbon inputs to soil (SOM depleted in nitrogen, enriched in hydrogen and in aromatic carbon). Our findings highlight the potential vulnerability of SOM stocks from proglacial areas to decomposition and suggest that their durability largely depends on the relative contribution of carbon inputs from plants
Beschreibung:	Date Completed 23.04.2021 Date Revised 23.04.2021 published: Print-Electronic Citation Status MEDLINE
ISSN:	1365-2486
DOI:	10.1111/gcb.15496