Data from: Long-term dynamics in microbial eukaryotes communities: a paleolimnological view based on sedimentary DNA

Assessing the extent to which changes in lacustrine biodiversity are affected by anthropogenic or climatic forces requires extensive palaeolimnological data. We used high-throughput sequencing to generate time-series data encompassing over 2200 years of microbial eukaryotes (protists and Fungi) diversity changes from the sedimentary DNA record of two lakes (Lake Bourget in French Alps and Lake Igaliku in Greenland). From 176 samples, we sequenced a large diversity of microbial eukaryotes, with a total 16 386 operational taxonomic units distributed within 50 phylogenetic groups. Thus, microbial groups, such as Chlorophyta, Dinophyceae, Haptophyceae and Ciliophora, that were not previously considered in lacustrine sediment record analyses appeared to be potential biological markers of trophic status changes. Our data suggest that shifts in relative abundance of extant species, including shifts between rare and abundant taxa, drive ecosystem responses to local and global environmental changes. Community structure shift events were concomitant with major climate variations (more particularly in Lake Igaliku). However, this study shows that the impacts of climatic fluctuations may be overpassed by the high-magnitude eutrophication impacts, as observed in the eutrophicated Lake Bourget. Overall, our data show that DNA preserved in sediment constitutes a precious archive of information on past biodiversity changes.

要评估湖泊生物多样性变化受人为活动或气候驱动的程度，需依托大量古湖沼学（palaeolimnological）数据。本研究采用高通量测序（high-throughput sequencing）技术，对两座湖泊的沉积DNA（sedimentary DNA）记录开展分析，这两座湖泊分别为法国阿尔卑斯山脉的布尔热湖（Lake Bourget）与格陵兰的伊加利库湖（Lake Igaliku），最终生成了涵盖2200余年的真核微生物——原生生物（protists）与真菌（Fungi）——多样性变化的时间序列数据。本次研究从176份沉积物样本中测序得到了丰富的真核微生物类群，共计获得16386个操作分类单元（operational taxonomic units, OTU），隶属于50个系统发育类群（phylogenetic groups）。由此可见，此前在湖泊沉积记录分析中未受关注的绿藻门（Chlorophyta）、甲藻纲（Dinophyceae）、定鞭藻纲（Haptophyceae）以及纤毛虫门（Ciliophora）等微生物类群，可作为营养状态（trophic status）变化的潜在生物标志物（biological markers）。本研究数据显示，现存物种的相对丰度变化——包括稀有类群与优势类群间的丰度转换——是驱动生态系统响应局地与全球环境变化的核心因素。群落结构转变事件与重大气候波动呈现同步性，这一现象在伊加利库湖中尤为显著。然而本研究表明，正如富营养化（eutrophication）的布尔热湖所观测到的那样，高强度富营养化的影响可能会盖过气候波动的效应。总体而言，本研究数据证实，沉积物中保存的DNA是记录过去生物多样性变化的珍贵信息档案。