A Continental-Scale Assessment of Linkages Between Soil Organic Matter Stabilization Mechanisms, Controls and Vulnerability.

The network of observation sites and scientific resources established by the National Ecological Observatory Network (NEON) create powerful opportunities for large-scale soils research. With eleven of the twelve soil orders recognized by USDA taxonomy represented within its continental-scale design, NEON is creating community access to samples and data from both pit and core sampling of a diverse set of soils. Here, we describe how these resources are facilitating a multi-institutional, collaborative investigation to understand the distribution of soil organic matter (SOM) stocks, their stability and vulnerability at 40 NEON sites. This project, supported by the National Science Foundation (Biological Sciences Directorate, MacroSystems Biology Program), brings together a team of academic and agency investigators with a demonstrated commitment to science as a community-oriented, collaborative venture. The project team will utilize cores to be extracted in winter 2014-15 in order to deploy soil sensors (e.g., moisture, temperature), and which would otherwise be discarded, for a battery of analytical tests. Cores will be separated by genetic horizon, characterized according to standard laboratory physical and chemical analyses, and exposed to powerful quantitative assays including X-ray diffraction and radiocarbon analysis. The experimental design includes density fractionation to elucidate the dynamics of discrete SOM pools, as well as a long-term incubation experiment to understand SOM vulnerability to changes in soil moisture and temperature regimes. We will integrate the datasets resulting from these analyses with climate, vegetation, and microbial parameters generated by NEON, permitting insight into the influence of factors ranging from distal (e.g., climate and climate change) to proximal (soil physicochemical factors) on SOM stability. A core objective of this project is to broaden researcher access to soil samples and datasets from NEON sites; thus, the project team invites collaborators to conduct add-on studies or related research using shared scientific resources.