Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA.
Ecole Normale Supérieure, Laboratoire de Géologie, Département de Géosciences, PSL University, Institut Pierre Simon Laplace, Paris, France.
Geobiology. 2024 Nov-Dec;22(6):e70004. doi: 10.1111/gbi.70004.
The importance of biota to soil formation and landscape development is widely recognized. As biotic complexity increases during early succession via colonization by soil microbes followed by vascular plants, effects of biota on mineral weathering and soil formation become more complex. Knowledge of the interactions among groups of organisms and environmental conditions will enable us to better understand landscape evolution. Here, we used experimental columns of unweathered granular basalt to investigate how early successional soil microbes, vascular plants (alfalfa; Medicago sativa), and soil moisture interact to affect both plant performance and mineral weathering. We found that the presence of soil microbes reduced plant growth rates, total biomass, and survival, which suggests that plants and microbes were competing for nutrients in this environment. However, we also found considerable genotype-specific variation in plant-microbial interactions, which underscores the importance of within-species genetic variation on biotic interactions. We also found that the presence of vascular plants reduced variability in pH and electrical conductivity, suggesting that plants may homogenize weathering reactions across the soil column. We also show that there is heterogeneity in the abiotic conditions in which microbes, plants, or their combination have the strongest effect on weathering, and that many of these relationships are sensitive to soil moisture. Our findings highlight the importance of interdependent effects of environmental and biotic factors on weathering during initial landscape formation.
生物群落在土壤形成和景观发育中的重要性已被广泛认识。随着早期演替中土壤微生物和维管束植物的定殖，生物复杂性增加，生物对矿物风化和土壤形成的影响变得更加复杂。了解生物群体之间的相互作用和环境条件将使我们能够更好地理解景观演化。在这里，我们使用未风化的粒状玄武岩实验柱来研究早期演替的土壤微生物、维管束植物（紫花苜蓿；Medicago sativa）和土壤水分如何相互作用，影响植物的表现和矿物风化。我们发现土壤微生物的存在降低了植物的生长速度、总生物量和存活率，这表明植物和微生物在这种环境中竞争养分。然而，我们也发现植物-微生物相互作用存在相当大的基因型特异性变异，这突显了种内遗传变异对生物相互作用的重要性。我们还发现维管束植物的存在降低了 pH 值和电导率的变异性，表明植物可能使土壤柱中的风化反应均匀化。我们还表明，在微生物、植物或它们的组合对风化影响最强的非生物条件存在异质性，并且许多这些关系对土壤水分敏感。我们的研究结果强调了环境和生物因素相互依存的影响对初始景观形成过程中风化的重要性。
