DNA-Metabarcoding of phyto- and zooplankton in East African lake sediments as proxies for past environmental perturbation

湖泊沉积物岩心提供了过去环境变化的自然档案，传统上用沉积学、地球化学和古生物学方法进行分析。最近，沉积物岩心的样本也进行了分子DNA分析，目标是土壤微生物的生活群落或过去居住在湖泊和/或其表面沉积物的生物残留物。本项目旨在结合最先进的环境基因组学技术和古代DNA分析技术，评估在Chew Bahir沉积物岩心中进行DNA元条形码编码的可能性。该项目解决的主要研究问题是：(1)从Chew Bahir沉积物岩心中提取和分析DNA残余物可以追溯到多远的时间？(2)基于pcr的元条形码与基于杂交捕获的元条形码结果的一致性如何？(3) Chew Bahir记录的浮游生物群落的长期趋势和变化是什么？该项目的结果将为理解过去环境与生物圈之间的相互作用，特别是在沉积物中，提供重要的贡献，在这些沉积物中，显微镜下可识别的有机残留物很少或不存在。此外，我们期望在热带湖泊沉积物研究方面取得重要的方法学进展，这将在未来的项目中具有重要意义。

Lake-sediment cores provide natural archives of past environmental changes, traditionally analyzed with sedimentological, geochemical and paleontological methods. More recently, samples from sediment cores have also been subjected to molecular DNA analysis, targeting either the living community of soil microbes or remnants of organisms that inhabited the lake and/or its surface sediment in the past. The project proposed here aims at evaluating the possibility for DNA metabarcoding in the Chew Bahir sediment cores, combining state-of-the-art techniques of environmental genomics and ancient DNA analysis. The principal research questions addressed by the project are: (1) How far back in time can DNA remnants in the Chew Bahir sediment cores be extracted and analyzed? (2) How congruent are the results of PCR-based vs. hybridization-capture-based metabarcoding? and (3) What are the long-term trends and shifts in the plankton communities in the Chew Bahir record? The results of this project will provide an important contribution to the understanding of interactions between the environment and the biosphere in the past, particularly in sediments, in which microscopically recognizable organic remains are scarce or absent. Furthermore, we expect important methodological advances in the study of sediments of tropical lakes, which will be in future projects of great importance.