Speaker
Description
In forest ecosystems, tree diversity and associated mycorrhiza types greatly shape microbial activity and functioning by altering resource availability and interactions among trees, mycorrhizal fungi, and microbial communities. However, the extent to which tree- mycorrhizal interactions regulate microbial growth and resource use strategies across seasons remains poorly understood. Using the MyDiv experiment, a 10-year temperate forest biodiversity platform, we examined the response of microbial physiological properties and extracellular enzyme activities to a gradient of tree diversity (1, 2, and 4 species) and mycorrhizal associations (arbuscular mycorrhizal, AM; ectomycorrhizal, EM; and mixed, AM+EM) in spring and autumn 2025. We found that tree diversity and mycorrhizal type independently affected microbial physiology. Specifically, tree diversity enhanced microbial biomass and DNA synthesis rate, but did not significantly alter carbon use efficiency (CUE). Seasonality had a strong effect on microbial physiological properties, with total microbial growth, respiration, and uptake increasing 1.5- to 3-fold from spring to autumn. These seasonal responses were particularly pronounced in EM-associated plots, which exhibited significantly larger microbial uptake, respiration, and DNA-based growth in autumn compared to AM-associated plots, while maintaining relatively stable CUE. Extracellular enzyme activities further revealed contrasting microbial nutrient-acquisition strategies between mycorrhizal systems. AM-associated soils showed greater investment in β-glucosidase targeting labile carbon substrates, while EM-associated soils exhibited higher nitrogen-acetylglucosaminidase activities. Notably, the maintenance of relatively stable CUE in EM-associated soils despite higher metabolic investment suggests that increased resource acquisition did not constrain microbial growth efficiency. Overall, our findings demonstrate that AM- and EM-associated forests support distinct seasonal microbial carbon-cycling strategies. AM systems favor rapid carbon acquisition, whereas EM systems promote seasonally intensified nutrient mining and accelerated cellular turnover without compromising growth efficiency, with potential implications for soil carbon cycling in temperate forest ecosystems.
| Status Group | Postdoctoral Researcher |
|---|---|
| FOR TALKS: Poster Presentation Option | Yes, I’m willing to present as a poster. |