As Arctic soils warm, thawed permafrost releases nitrogen (N) that could stimulate plant productivity and thus offset soil carbon losses from tundra ecosystems. Although mycorrhizal fungi could facilitate plant access to permafrost‐derived N, their exploration capacity beyond host plant root systems into deep, cold active layer soils adjacent to the permafrost table is unknown. We characterized root‐associated fungi (RAF) that colonized ericoid (ERM) and ectomycorrhizal (ECM) shrub roots and occurred below the maximum rooting depth in permafrost thaw‐front soil in tussock and shrub tundra communities. We explored the relationships between root and thaw front fungal composition and plant uptake of a15N tracer applied at the permafrost boundary. We show that ERM and ECM shrubs associate with RAF at the thaw front providing evidence for potential mycelial connectivity between roots and the permafrost boundary. Among shrubs and tundra communities, RAF connectivity to the thaw boundary was ubiquitous. The occurrence of particular RAF in both roots and thaw front soil was positively correlated with15N recovered in shrub biomass Taxon‐specific RAF associations could be a mechanism for the vertical redistribution of deep, permafrost‐derived nutrients, which may alleviate N limitation and stimulate productivity in warming tundra.
This content will become publicly available on January 25, 2025
- NSF-PAR ID:
- 10493896
- Publisher / Repository:
- New Phytologist
- Date Published:
- Journal Name:
- New Phytologist
- ISSN:
- 0028-646X
- Subject(s) / Keyword(s):
- ["Alaska","dark septate endophyte","ectomycorrhizal fungi","ericoid mycorrhizal fungi","isotope 15N","moist acidic tundra","shrub expansion"]
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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