人类和非人类动物尸体的微生物群落组装(MCA)提供了可用于估计陆地环境中的死后间隔(PMI)的指标。然而,估计水生栖息地的死后淹没间隔(PMSI)的研究较少。迄今为止,没有水生研究在死亡调查的背景下评估MCA,所有以前的研究都集中在重要的基本生态问题上。在一起悬案调查的背景下,我们使用复制的成年猪尸体进行了一项实验,以描述不流动的水生生境中的死后MCA变异性。使用car体死后微生物组的高通量测序,我们描述了MCA的变异性,并确定了在与寒冷病例体恢复地点相似的水生栖息地中与分解相关的关键分类单元。我们还对用于估计PMSI的关键分类单元进行了建模,使用随机森林回归在±3天内(均方误差)进行建模。我们的发现表明,随着分解的进行,微生物群落发生了重大变化,几个分类单元被确定为重要的指示分类单元,可能对未来的PMSI估计有用。虽然是描述性的,这项研究提供了量化非流动水生生境中MCA变异性的初步发现。在悬案调查的背景下,我们讨论了在尸体恢复时收集的死后微生物样本如何成为理解回收遗骸PMSI的重要证据.需要进行其他实验研究,以明确测试和识别与其他栖息地和不同温度下的死后MCA变异性相关的机制(例如,季节)条件。
Microbial community assembly (MCA) of both human and nonhuman animal carcasses provides indicators useful for estimating the postmortem interval (PMI) in terrestrial settings. However, there are fewer studies estimating postmortem submersion intervals (PMSIs) in aquatic habitats. No aquatic studies to date assessed MCA in the context of a death investigation, with all previous studies focusing on important basic ecological questions. Within the context of a cold
case investigation, we performed an experiment using replicate adult swine carcasses to describe postmortem MCA variability within a nonflowing aquatic habitat. Using high-throughput sequencing of carcass postmortem microbiomes, we described MCA variability and identified key taxa associated with decomposition in an aquatic habitat similar to the cold
case body recovery site. We also modeled key taxa for estimating PMSIs, modeling within ±3 days (mean square error) postmortem using random forest regression. Our findings show significant changes in microbial communities as decomposition progressed, and several taxa were identified as important indicator taxa which may be useful for future estimates of PMSI. While descriptive, this study provides initial findings quantifying MCA variability within a nonflowing aquatic habitat. Within the context of the cold
case investigation, we discuss how postmortem microbial samples collected at the time of body recovery could have been an important piece of evidence for understanding the PMSI of recovered remains. Additional experimental studies are needed to explicitly test and identify mechanisms associated with postmortem MCA variability in other habitats and under different temperature (e.g., seasons) conditions.