Investigations into the transfer of carbon from plant litter to underlying soil horizons has primarily focused on the leaching of soluble carbon from litter belowground or the mixing of litter directly into soil. However, previous work has largely ignored the role of volatile organic compounds (VOCs) released during litter decomposition. Unlike most leaf carbon, these litter-derived VOCs are able to diffuse directly into the soil matrix. Here, we used a 99-day microcosm experiment to track VOCs produced during microbial decomposition of 13 C-labeled leaf litter into soil carbon fractions where the decomposing litters were only sharing headspace with the soil samples, thus preventing direct contact and aqueous movement of litter carbon. We also determined the effects of these litter-derived VOCs on soil microbial community structure. We demonstrated that the litter VOCs contributed to all measured soil carbon pools. Specifically, VOC derived carbon accounted for 2.0, 0.61, 0.18, and 0.08% of carbon in the microbial biomass, dissolved organic matter, mineral associated organic matter, and particulate organic matter pools, respectively. We also show that litter-derived VOCs can affect soil bacterial and fungal community diversity and composition. These findings highlight the importance of an underappreciated pathway where VOCs alter soil microbial communities and carbon dynamics.

中文翻译：

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来自凋落物分解的挥发性有机化合物改变土壤微生物群落和碳动态

对碳从植物凋落物转移到下层土壤层的研究主要集中在可溶性碳从地下凋落物浸出或将凋落物直接混合到土壤中。然而，以前的工作在很大程度上忽略了垃圾分解过程中释放的挥发性有机化合物 (VOC) 的作用。与大多数叶碳不同，这些凋落物衍生的 VOC 能够直接扩散到土壤基质中。在这里，我们使用了一个为期 99 天的微观实验来跟踪 13 C 标记的树叶凋落物微生物分解成土壤碳部分期间产生的 VOC，其中分解的凋落物仅与土壤样品共享顶部空间，从而防止凋落物的直接接触和水运动碳。我们还确定了这些凋落物衍生的 VOC 对土壤微生物群落结构的影响。我们证明了凋落物 VOC 对所有测量的土壤碳库都有贡献。具体而言，VOC衍生的碳分别占微生物生物量、溶解有机物、矿物伴生有机物和颗粒有机物池中碳的2.0%、0.61%、0.18%和0.08%。我们还表明，凋落物衍生的 VOC 会影响土壤细菌和真菌群落的多样性和组成。这些发现强调了一个未被充分认识的途径的重要性，在这个途径中 VOC 改变了土壤微生物群落和碳动力学。我们还表明，凋落物衍生的 VOC 会影响土壤细菌和真菌群落的多样性和组成。这些发现强调了一个未被充分认识的途径的重要性，在这个途径中 VOC 改变了土壤微生物群落和碳动力学。我们还表明，凋落物衍生的 VOC 会影响土壤细菌和真菌群落的多样性和组成。这些发现强调了一个未被充分认识的途径的重要性，在这个途径中 VOC 改变了土壤微生物群落和碳动力学。