Submicron structures provide preferential spots for carbon and nitrogen sequestration in soils

• Published in: Nature communications Vol. 5; no. 1; p. 2947
• Main Authors: Vogel, Cordula, Mueller, Carsten W., Höschen, Carmen, Buegger, Franz, Heister, Katja, Schulz, Stefanie, Schloter, Michael, Kögel-Knabner, Ingrid
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2014; Nature Publishing Group; Nature Pub. Group
• Subjects: 704/106/47; Biomass; Carbon; Environmental health; Humanities and Social Sciences; Mass spectrometry; multidisciplinary; Nitrogen; Scanning electron microscopy; Science; Science (multidisciplinary); Scientific imaging; Sediments; Germany
• ISSN: 2041-1723
• DOI: 10.1038/ncomms3947

The sequestration of carbon and nitrogen by clay-sized particles in soils is well established, and clay content or mineral surface area has been used to estimate the sequestration potential of soils. Here, via incubation of a sieved (<2 mm) topsoil with labelled litter, we find that only some of the clay-sized surfaces bind organic matter (OM). Surprisingly, <19% of the visible mineral areas show an OM attachment. OM is preferentially associated with organo-mineral clusters with rough surfaces. By combining nano-scale secondary ion mass spectrometry and isotopic tracing, we distinguish between new labelled and pre-existing OM and show that new OM is preferentially attached to already present organo-mineral clusters. These results, which provide evidence that only a limited proportion of the clay-sized surfaces contribute to OM sequestration, revolutionize our view of carbon sequestration in soils and the widely used carbon saturation estimates. Clay-sized particles bind organic matter and sequester carbon and nitrogen in soils, yet extent and localization of organic matter coverage remain unclear. Using NanoSIMS, Vogel et al. chemically image soils at ultra-high resolution and show that only particles with rough surfaces react with organic matter.