Fungi and bacteria are the two dominant groups of soil microbial communities worldwide. By controlling the turnover of soil organic matter, these organisms directly regulate the cycling of carbon between the soil and the atmosphere. Fundamental differences in the physiology and life history of bacteria and fungi suggest that variation in the biogeography of relative abundance of soil fungi versus bacteria could drive striking differences in carbon decomposition and soil organic matter formation between different biomes. However, a lack of global and predictive information on the distribution of these organisms in terrestrial ecosystems has prevented the inclusion of relative abundance of soil fungi versus bacteria and the associated processes in global biogeochemical models. Here, we used a global-scale dataset of >3000 distinct observations of abundance of soil fungi versus bacteria in the surface topsoil (up to 15 cm) to generate the first quantitative and high-spatial-resolution (1 km²) explicit map of soil fungal proportion, defined as fungi/fungi + bacteria, across terrestrial ecosystems. We reveal striking latitudinal trends where fungal dominance increases in cold and high-latitude environments with large soil carbon stocks. There was a strong nonlinear response of fungal dominance to the environmental gradient, i.e., mean annual temperature (MAT) and net primary productivity (NPP). Fungi dominated in regions with low MAT and NPP and bacteria dominated in regions with high MAT and NPP, thus representing slow vs. fast soil energy channels, respectively, a concept with a long history in soil ecology. These high-resolution models provide the first steps towards representing the major soil microbial groups and their functional differences in global biogeochemical models to improve predictions of soil organic matter turnover under current and future climate scenarios. Raw datasets and global maps generated in this study are available at https://doi.org/10.6084/m9.figshare.19556419 (Yu, 2022).

中文翻译：

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表层土壤中土壤真菌与细菌相对丰度的生物地理学

真菌和细菌是全球土壤微生物群落的两大主要群体。通过控制土壤有机质的周转，这些生物直接调节土壤和大气之间的碳循环。细菌和真菌生理学和生活史的根本差异表明，土壤真菌与细菌相对丰度的生物地理学差异可能导致不同生物群落之间碳分解和土壤有机质形成的显着差异。然而，由于缺乏关于这些生物在陆地生态系统中分布的全球性和预测性信息，因此无法将土壤真菌与细菌的相对丰度以及相关过程纳入全球生物地球化学模型中。在这里，我们使用了>3000的全球规模数据集对表层土壤（高达 15 cm）中土壤真菌与细菌丰度的不同观察，以生成第一个定量和高空间分辨率（1 km ²）土壤真菌比例的显式地图，定义为真菌/真菌 + 细菌，跨越陆地生态系统。我们揭示了惊人的纬度趋势，其中真菌优势在寒冷和高纬度环境中具有大量土壤碳储量增加。真菌优势对环境梯度有很强的非线性响应，即年平均温度（MAT）和净初级生产力（NPP）。真菌在 MAT 和 NPP 低的地区占优势，细菌在 MAT 和 NPP 高的地区占优势，因此分别代表了慢速和快速土壤能量通道，这是土壤生态学中历史悠久的概念。这些高分辨率模型为代表主要土壤微生物群及其在全球生物地球化学模型中的功能差异提供了第一步，以改进对当前和未来气候情景下土壤有机质周转的预测。