Microbial biomass – not diversity – drives soil carbon and nitrogen mineralization in Spanish holm oak ecosystems

作者：Elisa Bruni, Jorge Curiel Yuste, Lorenzo Menichetti, Omar Flores, Daniela Guasconi, Bertrand Guenet, Ana‐Maria Hereş, Aleksi Lehtonen, Raisa Mäkipää, Marleen Pallandt, Leticia Pérez‐Izquierdo, Étienne Richy, Mathieu Santonja, Boris Ťupek, Stefano Manzoni · 发表于：Geoderma · 年份：2025 · DOI：10.1016/j.geoderma.2025.117408 · 被引用次数：10 · 研究领域：Peatlands and Wetlands Ecology、Forest Ecology and Biodiversity Studies、Soil Carbon and Nitrogen Dynamics

Soil microbial communities drive essential ecosystem functions, catalyzing biogeochemical cycles and contributing to climate regulation. However, due to the complexity of microbial communities, the magnitude and direction of microbial biomass and diversity contributions to carbon (C) and nutrient cycling remain unclear. For this reason, most models predicting soil organic matter (SOM) dynamics at the ecosystem level do not explicitly describe the role of microorganisms as mediators of SOM decomposition. Incorporating microbial properties, and especially diversity, into ecosystem models remains an open question, requiring careful consideration of the tradeoff between model complexity and performance. This work addresses this knowledge gap by implementing a simple C and nitrogen (N) cycling model to predict heterotrophic respiration and net N mineralization rates in soils sampled under different land-uses and tree health conditions across Spain. To understand the role of microorganisms on ecosystem functioning, we progressively incorporated microbial biomass and diversity (i.e., alpha diversity of taxa and of fungal functional groups), and selected the model that optimized prediction accuracy, while minimizing complexity. We found that microbial biomass had a strong and positive effect on both C and N mineralization rates, with heterotrophic respiration being nearly linearly controlled by biomass. In contrast, microbial diversity had minimal but negative effects on mineralizati...