¹⁴C is known as one of the radionuclides that have potential to be released into the biosphere from radioactive waste repositories and taken up by organisms. In this study, we used a novel approach to investigate the proportion of soil organic carbon (SOC) in invertebrates and microbial biomass. The study was conducted on a peatland site after the end of peat extraction. There was a large difference in the isotopic abundance of ¹⁴C between the 8000-year-old peat and air. We used a two-pool isotope mixing model to reveal the fraction of soil-derived C in the organisms and in dissolved organic carbon in soil water. The contribution of soil-derived C was found to be highest in microbial biomass (61%) and earthworms (22%). Some contribution of soil-derived C was detected in fungus gnats (2%), but not in other insects or in spiders. These findings are important for developing evidence-based radioecological models based on correct understanding of the relative contributions of atmospheric C vs. SOC in organisms.

¹⁴ C被认为是一种放射性核素，它有潜力从放射性废物库释放到生物圈中并被生物吸收。在这项研究中，我们使用一种新颖的方法来研究无脊椎动物和微生物生物量中土壤有机碳（SOC）的比例。泥炭提取结束后，该研究在泥炭地进行。同位素丰度为¹⁴C在具有8000年历史的泥炭和空气之间。我们使用了一个两池同位素混合模型来揭示生物体和土壤水中溶解有机碳中土壤衍生的碳的比例。发现土壤中碳的贡献在微生物生物量（61％）和worm（22％）中最高。在真菌（2％）中检测到了土壤来源的碳的某些贡献，但在其他昆虫或蜘蛛中未检测到。这些发现对于建立基于证据的放射生态学模型非常重要，该模型基于对有机物中大气C与SOC相对贡献的正确理解。