Food-web control of the global topsoil carbon cycling (CARBONWEB)

Soil food webs process 90% of the terrestrial primary production and regulate the largest carbon pool on Earth – soil organic matter. Soil food webs themselves are regulated by soil animals through changes in microbial functioning, detritus quality, and soil structure, but nor global drivers of soil food web structure and functions, neither their effects on global biogeochemistry and carbon stabilisation are quantified. CARBONWEB addresses this knowledge gap and tests the following Key Hypotheses: (A) resource and top-down controls of soil food-web structure and functions increase under conditions promoting biological activity and nutrient limitation; (B) translocation and transformation of detritus by consumers in soil food web increases stable fraction of soil carbon across ecosystem types; (C) the effect of soil animals on multiple ecosystem functions increases with temperature, precipitation, and nutrient limitation, proportionally to the total energy flux in soil food webs; (D) the global net effect of soil animals on topsoil carbon concentration is positive, considerable (>10% increase), and will increase with climate warming. To test these hypotheses, we will use (1) the first comprehensive global assessment of soil animal communities in the framework of Soil BON, (2) EU-wide survey and experiments on carbon stabilisation, (3) AI-based image analysis approaches and dynamic food-web modelling, and (4) geospatial extrapolations. Results of the project will provide the first-ever global estimation of soil food web effects on soil functioning and establish the basis for a long-term monitoring of global soil biodiversity, describing the present and future of global soils and contributing to the long-term basis of human well-being. The project is funded in the framework of ERC Consolidator Grant program (2025-2030).