IMPACT4SOIL OpenAire Datacite unspecified 2021-06-15 unspecifiedTundra ecosystems are global belowground sinks for atmospheric CO2. Ongoing warming-induced encroachment by shrubs and trees risks turning this sink into a CO2 source, resulting in a positive feedback on climate warming. To advance mechanistic understanding of how shifts in mycorrhizal types affect long-term carbon (C) and nitrogen (N) stocks, we studied small-scale soil depth profiles of fungal communities and C-N dynamics across a subarctic-alpine forest-heath vegetation gradient. Belowground organic stocks decreased abruptly at the transition from heath to forest, linked to the presence of certain tree-associateds ectomycorrhizal fungi that contribute to decomposition when mining N from organic matter. In contrast, ericoid mycorrhizal plants and fungi were associated with organic matter accumulation and slow decomposition. If climatic controls on arctic-alpine forest lines are relaxed, increased decomposition will likely outbalance increased plant productivity, decreasing the overall C sink capacity of displaced tundra. unspecifiedTundra ecosystems are global belowground sinks for atmospheric CO2. Ongoing warming-induced encroachment by shrubs and trees risks turning this sink into a CO2 source, resulting in a positive feedback on climate warming. To advance mechanistic understanding of how shifts in mycorrhizal types affect long-term carbon (C) and nitrogen (N) stocks, we studied small-scale soil depth profiles of fungal communities and C-N dynamics across a subarctic-alpine forest-heath vegetation gradient. Belowground organic stocks decreased abruptly at the transition from heath to forest, linked to the presence of certain tree-associateds ectomycorrhizal fungi that contribute to decomposition when mining N from organic matter. In contrast, ericoid mycorrhizal plants and fungi were associated with organic matter accumulation and slow decomposition. If climatic controls on arctic-alpine forest lines are relaxed, increased decomposition will likely outbalance increased plant productivity, decreasing the overall C sink capacity of displaced tundra. Soil samples were taken in 24 plots representing four vegetation types along a subarctic-alpine birch forest-heath tundra ecotone in Northern Sweden. Soil cores were split into fine-scaled layers, which were analysed for various biochemical characteristics and for fungal communities based on ITS2 meta-barcoding. Please find all details on sampling and analyses in the associated paper. C-N dynamics ectomycorrhizal exploration type functional genes ergosterol ITS2 meta-barcoding Fungal community Arctic greening Climate feedback 15. Life on land litter saprotrophs mycorrhizal type litter bags 13. Climate action soil solution FOS: Biological sciences soil carbon storage quantitative PCR soil profiles Ectomycorrhizal fungal community Ericoid Mycorrhiza treeline ecotone Clemmensen, Karina E, Durling, Mikael B, Michelsen, Anders, Hallin, Sara, Finlay, Roger D, Lindahl, Björn D, 2022-02-28 unspecifiedTundra ecosystems are global belowground sinks for atmospheric CO2. Ongoing warming-induced encroachment by shrubs and trees risks turning this sink into a CO2 source, resulting in a positive feedback on climate warming. To advance mechanistic understanding of how shifts in mycorrhizal types affect long-term carbon (C) and nitrogen (N) stocks, we studied small-scale soil depth profiles of fungal communities and C-N dynamics across a subarctic-alpine forest-heath vegetation gradient. Belowground organic stocks decreased abruptly at the transition from heath to forest, linked to the presence of certain tree-associateds ectomycorrhizal fungi that contribute to decomposition when mining N from organic matter. In contrast, ericoid mycorrhizal plants and fungi were associated with organic matter accumulation and slow decomposition. If climatic controls on arctic-alpine forest lines are relaxed, increased decomposition will likely outbalance increased plant productivity, decreasing the overall C sink capacity of displaced tundra. unspecifiedTundra ecosystems are global belowground sinks for atmospheric CO2. Ongoing warming-induced encroachment by shrubs and trees risks turning this sink into a CO2 source, resulting in a positive feedback on climate warming. To advance mechanistic understanding of how shifts in mycorrhizal types affect long-term carbon (C) and nitrogen (N) stocks, we studied small-scale soil depth profiles of fungal communities and C-N dynamics across a subarctic-alpine forest-heath vegetation gradient. Belowground organic stocks decreased abruptly at the transition from heath to forest, linked to the presence of certain tree-associateds ectomycorrhizal fungi that contribute to decomposition when mining N from organic matter. In contrast, ericoid mycorrhizal plants and fungi were associated with organic matter accumulation and slow decomposition. If climatic controls on arctic-alpine forest lines are relaxed, increased decomposition will likely outbalance increased plant productivity, decreasing the overall C sink capacity of displaced tundra. Soil samples were taken in 24 plots representing four vegetation types along a subarctic-alpine birch forest-heath tundra ecotone in Northern Sweden. Soil cores were split into fine-scaled layers, which were analysed for various biochemical characteristics and for fungal communities based on ITS2 meta-barcoding. Please find all details on sampling and analyses in the associated paper. Data from: A tipping-point in carbon storage when forest expands into tundra is related to mycorrhizal recycling of nitrogen 10.5061/dryad.79cnp5htw dataset https://doi.org/10.5061/dryad.79cnp5htw