Data from: Lake sediment multi-taxon DNA from North Greenland records early post-glacial appearance of vascular plants and accurately tracks environmental changes

High Arctic environments are particularly sensitive to climate changes, but retrieval of paleoecological data is challenging due to low productivity and biomass. At the same time, Arctic soils and sediments have proven exceptional for long-term DNA preservation due to their constantly low temperatures. Lake sediments contain DNA paleorecords of the surrounding ecosystems and can be used to retrieve a variety of organismal groups from a single sample. In this study, we analyzed vascular plant, bryophyte, algal (in particular diatom) and copepod DNA retrieved from a sediment core spanning the Holocene, taken from Bliss Lake on the northernmost coast of Greenland. A previous multi-proxy study including microscopic diatom analyses showed that this lake experienced changes between marine and lacustrine conditions. We inferred the same environmental changes from algal DNA preserved in the sediment core. Our DNA record was stratigraphically coherent, with no indication of leaching between layers, and our cross-taxon comparisons were in accordance with previously inferred local ecosystem changes. Authentic ancient plant DNA was retrieved from nearly all layers, both from the marine and the limnic phases, and distinct temporal changes in plant presence were recovered. The plant DNA was mostly in agreement with expected vegetation history, but very early occurrences of vascular plants, including the woody Empetrum nigrum, document terrestrial vegetation very shortly after glacial retreat. Our study shows that multi-taxon metabarcoding of sedimentary ancient DNA from lake cores is a valuable tool both for terrestrial and aquatic paleoecology, even in low-productivity ecosystems such as the High Arctic.

高北极（High Arctic）环境对气候变化尤为敏感，但受限于较低的生产力与生物量，古生态数据（paleoecological data）的获取颇具挑战。与此同时，北极地区的土壤与沉积物因常年维持低温，被证实是长期DNA保存的极佳载体。湖泊沉积物（Lake sediments）蕴含周边生态系统的DNA古记录（DNA paleorecords），仅需单一样本即可获取多种生物类群的遗传信息。本研究对取自格陵兰最北端海岸布利斯湖（Bliss Lake）的全新世（Holocene）沉积物岩芯（sediment core）中提取的维管植物、苔藓植物（bryophyte）、藻类（algal）（尤以硅藻（diatom）为代表）以及桡足类（copepod）的DNA进行了分析。此前一项包含显微镜硅藻分析的多代用指标研究显示，该湖泊曾经历海洋与湖相（lacustrine）环境的交替更迭。本研究从沉积物岩芯中保存的藻类DNA中，同样推断出了这类环境变化。我们的DNA记录在地层学上具有一致性，未发现层间淋滤（leaching）的迹象，且跨类群（cross-taxon）比对结果与此前推断的当地生态系统变化相符。研究人员从几乎所有层位（包括海洋相与淡水相（limnic phases））中均提取到了真实的古代植物DNA，并获取了植物存在情况的显著时间演化特征。植物DNA结果整体与预期的植被演化历史相符，但包括木本植物黑岩高兰（Empetrum nigrum）在内的维管植物的极早期出现记录，证明冰川退缩（glacial retreat）后不久该区域便已形成陆地植被。本研究表明，即便在高北极这类低生产力生态系统中，对湖泊岩芯沉积古DNA开展多类群元条形码测序（multi-taxon metabarcoding）分析，仍是用于陆地与水生古生态学研究的可靠工具。