Mandolini Edoardo, Probst Maraike, Telagathoti Anusha, Frey Beat, Rodriguez-R Luis M, Fornasier Flavio, Praeg Nadine, Illmer Paul, Peintner Ursula
Department of Microbiology, Universität Innsbruck, Innsbruck, Austria.
Forest Soils and Biogeochemistry, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland.
Appl Environ Microbiol. 2025 Jun 18;91(6):e0030225. doi: 10.1128/aem.00302-25. Epub 2025 May 15.
Calcareous glacier forefields challenge prevailing ecological frameworks on microbial biodiversity and community assembly due to their unique bedrock. Early stages of soil development in these environments are notorious for their high turnover rates, demanding a high degree of replication for obtaining conclusive data. However, studies across different calcareous glaciers are still missing. Here, we robustly investigated both bacterial and fungal diversity, association networks, and assembly processes in four calcareous glacier forefields of the Alps, focusing on the earliest soil developmental stages (<25 years) early in the snow-free season. We found a diverse community of bacteria and fungi, potentially involved in P and N nutrient cycling. A core microbiome existing across all four locations suggests that certain microbes might be more successful colonizers of these ecosystems than others. Nearest taxon index revealed phylogenetically clustered microbial communities. These findings suggest that the distribution and colonization of some microbes were influenced by selective forces such as geography and climate during the early stages of soil development in calcareous glaciers. Interestingly, there were no common bacterial-fungal associations across the four locations, indicating that this habitat does not select for specific bacterial-fungal associations and that associations were driven by neutral processes. We discuss microbial communities and their interactions in these special calcareous glacier forefield habitats. Moreover, we present innovative approaches for studying microbial assembly that address both deterministic, intrinsic drivers, like specific microbial traits, and stochastic, extrinsic drivers, such as the opportunistic behavior of microbes.IMPORTANCEOur study is based on three fundamental and unique approaches: (i) we utilize the early stages of soil development in four glacier forefields across the Alpine range. This design implies high replicability in a natural setting, which is crucial for drawing general conclusions. (ii) Our study investigates glacier forefields with calcareous bedrock directly after snowmelt. These habitats and periods remain surprisingly underexplored. (iii) Our results underline the relevance of bacterial-fungal associations in microbial community assembly alongside dispersal, drift, and natural selection. Taken together, our study provides new insights into the development of complex microbial communities, their stabilization and predictability, including ecological implications.
钙质冰川前缘由于其独特的基岩，对当前关于微生物多样性和群落组装的生态框架提出了挑战。这些环境中土壤发育的早期阶段因周转率高而声名狼藉，需要高度重复实验才能获得确凿的数据。然而，目前仍缺乏对不同钙质冰川的研究。在此，我们全面调查了阿尔卑斯山四个钙质冰川前缘的细菌和真菌多样性、关联网络及组装过程，重点关注无雪季节早期最早的土壤发育阶段（<25年）。我们发现了一个多样的细菌和真菌群落，它们可能参与了磷和氮的养分循环。在所有四个地点都存在的核心微生物组表明，某些微生物可能比其他微生物更能成功地在这些生态系统中定殖。最近分类单元指数显示微生物群落具有系统发育聚类特征。这些发现表明，在钙质冰川土壤发育的早期阶段，某些微生物的分布和定殖受到地理和气候等选择力的影响。有趣的是，四个地点之间没有共同的细菌 - 真菌关联，这表明该栖息地不会选择特定的细菌 - 真菌关联，且关联是由中性过程驱动的。我们讨论了这些特殊的钙质冰川前缘栖息地中的微生物群落及其相互作用。此外，我们提出了研究微生物组装的创新方法，该方法既考虑了确定性的内在驱动因素，如特定的微生物特征，也考虑了随机性的外在驱动因素，如微生物的机会主义行为。
重要性
（i）我们利用了阿尔卑斯山脉四个冰川前缘土壤发育的早期阶段。这种设计意味着在自然环境中具有高可重复性，这对于得出一般性结论至关重要。（ii）我们的研究在融雪后直接调查了具有钙质基岩的冰川前缘。这些栖息地和时期仍令人惊讶地未得到充分探索。（iii）我们的结果强调了细菌 - 真菌关联在微生物群落组装中与扩散、漂变和自然选择同样重要。综上所述，我们的研究为复杂微生物群落的发展、其稳定性和可预测性提供了新的见解，包括生态意义。
