Production dynamics of Cenococcum geophilum ectomycorrhizas in response to long-term elevated CO2 and N fertilization

Ectomycorrhizal fungi are important in many forest ecosystems, yet their production dynamics and responses to environmental changes are poorly understood. Cenococcum geophilum is a common ectomycorrhizal fungus important to plant and forest soil biogeochemical cycles. The seasonal and inter annual patterns of production and persistence of mycorrhizas formed by C geophilum in a pine forest exposed to elevated atmospheric CO2 and nitrogen fertilization were monitored using a 12 y minirhizotron dataset. Production of C geophilum mycorrhizas was distinctly seasonal and peaked in late summer/autumn. Elevated CO2 generally increased production while nitrogen fertilization strongly decreased production. Persistence times of C geophilum mycorrhizas was ca. 2.7 y and was unaffected by CO2 and nitrogen addition. Total production was greater in shallow soil (0-16 cm) but persistence was longer in deeper soil (17-32 cm). These observations provide insights into the autecology of C geophilum and suggest that its tissues may be slow to decompose compared to other ectomycorrhizal species. (C) 2016 Elsevier Ltd and British Mycological Society. All rights reserved.