Radiocarbon signature reveals that most springtails depend on carbon from living plants
Radiocarbon signature reveals that most springtails depend on carbon from living plants
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放射性碳特征表明大多数弹尾鱼依赖活植物中的碳
DOI：
10.1098/rsbl.2021.0353
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发表时间：
2021
期刊：
影响因子：
3.3
通讯作者：
Tayasu Ichiro
中科院分区：
文献类型：
--
作者：
Fujii Saori;Haraguchi Takashi F.;Tayasu Ichiro
陆地碳循环在很大程度上由土壤食物网介导。确定土壤动物的碳源是为了区分它们在碳循环中的作用，但由于方法上的限制，对于低营养级的小型无脊椎动物来说，这是一个挑战。本文结合放射性碳（14 C）分析和稳定同位素（13 C和15 N）分析，研究了土壤微型节肢动物的食性，特别是弹尾虫的食性。大多数弹尾目物种的Δ 14 C值低于凋落物，而不管它们的δ 13 C和δ 15 N特征如何，表明它们依赖于年轻的碳。与所有分类群的一般模式相比，我们发现土壤弹尾虫的δ 15 N和Δ 14 C值之间存在显著的负相关。这意味着具有较高δ 15 N值的物种依赖于最近的光合产物中的C，这表明土壤生活的物种通常以真菌为食以获得根源C。许多捕食性类群的Δ 14 C值高于弹尾目，但低于凋落物，表明弹尾目食性对土壤食物网的影响不可忽视。我们的研究证明了放射性碳分析的有用性，它可以解开改变弹尾虫δ 15 N值的混杂因素，澄清动物的食性，并确定生物在土壤食物网中的作用。
Terrestrial carbon cycling is largely mediated by soil food webs. Identifying the carbon source for soil animals has been desired to distinguish their roles in carbon cycling, but it is challenging for small invertebrates at low trophic levels because of methodological limitations. Here, we combined radiocarbon (14C) analysis with stable isotope analyses (13C and15N) to understand feeding habits of soil microarthropods, especially focusing on springtail (Collembola). Most Collembola species exhibited lower Δ14C values than litter regardless of theirδ13C andδ15N signatures, indicating their dependence on young carbon. In contrast with general patterns across all taxonomic groups, we found a significant negative correlation betweenδ15N and Δ14C values among the edaphic Collembola. This means that the species with higherδ15N values depend on C from more recent photosynthate, which suggests that soil-dwelling species generally feed on mycorrhizae to obtain root-derived C. Many predatory taxa exhibited higher Δ14C values than Collembola but lower than litter, indicating non-negligible effects of collembolan feeding habits on the soil food web. Our study demonstrated the usefulness of radiocarbon analysis, which can untangle the confounding factors that change collembolanδ15N values, clarify animal feeding habits and define the roles of organisms in soil food webs.