Plant DNA metabarcoding records from three cores of lacustrine lakes along a open larch forest-forest tundra-tundra transect at the Omoloy region, north-eastern Siberia

Here, we provide the raw plant DNA metabarcoding data archived in three Siberian lake sediment cores spanning the mid-Holocene to the present (7.6-0 cal ka BP), from northern typical tundra to southern open larch forest in the Omoloy region. There are three cores: 14-OM-20B, Lat. / °: 70.53, Lon. / °: 132.91, Ele. / m a.s.l.: 52, Modern vegetation: open larch forest, Lake area / km2: 0.26, Maximal depth / m: 3.4 14-OM-02B, Lat. / °: 70.72, Lon. / °: 132.67, Ele. / m a.s.l.: 58, Modern vegetation: forest tundra, Lake area / km2: 0.08, Maximal depth / m: 3.5 14-OM-12A, Lat. / °: 70.96, Lon. / °: 132.57, Ele. / m a.s.l.: 60, Modern vegetation: tundra, Lake area / km2: 0.09, Maximal depth / m: 4.5 Three lake sediment cores, 14OM12A (33 cm long), 14OM02B (49.5 cm long) and 14OM20B (86 cm long), were recovered from three sites using a UWITEC gravity corer (6 cm internal diameter) equipped with a hammer tool in July 2014. From the three cores, 16 bulk organic carbon samples were selected because of the lack of macrofossil remains and radiocarbon dated using accelerator mass spectrometry (AMS) at Poznań radiocarbon laboratory of Adam Mickiewicz University, Poland. In addition, 30 freeze-dried samples per core at 0.25 or 0.5 cm intervals between 0 and 15 cm were analysed for 210Pb/137Cs at the Liverpool University Environmental Radioactivity Laboratory. (The dating table has been submitted to PANGAEA) In this project, we analyse pollen (has been submitted to PANGAEA, doi: 10.1594/PANGAEA.922550) and sedaDNA from three lake sediment cores from the Omoloy region in north-eastern Siberia (northern Yakutia), which are currently surrounded by different vegetation types ranging from typical tundra to open larch forest. First, our aim is to compare sedaDNA with the pollen data to see whether both methods track the same pattern with respect to compositional changes and diversity changes across the northern Russian treeline zone or are complementary to each other. Second, we reconstruct the mid- to late-Holocene changes of vegetation composition along a north–south transect. Third, we use the sedaDNA data to reconstruct variations in species richness and relate this to vegetation and climate change.

本数据集提供了保存于西伯利亚奥莫洛伊地区3个湖泊沉积物岩芯中的原始植物DNA宏条形码（DNA metabarcoding）数据，这些岩芯的沉积序列覆盖中全新世至现代（7.6~0校准千年BP，cal ka BP），采样点涵盖从北部典型苔原到南部开阔落叶松林的植被梯度。
本次涉及的3个岩芯详细参数如下：
1. 14-OM-20B：纬度70.53°，经度132.91°，海拔52米（高于海平面），现代植被类型为开阔落叶松林，湖泊面积0.26 km²，最大水深3.4 m
2. 14-OM-02B：纬度70.72°，经度132.67°，海拔58米（高于海平面），现代植被类型为森林苔原，湖泊面积0.08 km²，最大水深3.5 m
3. 14-OM-12A：纬度70.96°，经度132.57°，海拔60米（高于海平面），现代植被类型为典型苔原，湖泊面积0.09 km²，最大水深4.5 m

2014年7月，研究团队采用搭载击入工具的UWITEC型重力取样器（内径6 cm）从3个采样点获取了上述3个沉积物岩芯，其中14-OM-12A长33 cm、14-OM-02B长49.5 cm、14-OM-20B长86 cm。
因缺乏大化石遗存，本研究选取16个块状有机碳样品，于波兰亚当·密茨凯维奇大学波兹南放射性碳实验室采用加速器质谱（AMS）完成放射性碳定年。此外，针对0~15 cm层段以0.25 cm或0.5 cm间隔采集的每个岩芯的30个冷冻干燥样品，研究团队在利物浦大学环境放射实验室开展了铅210（²¹⁰Pb）/铯137（¹³⁷Cs）分析。（定年表已提交至PANGAEA数据库）

本项目针对西伯利亚东北部雅库特北部奥莫洛伊地区的3个湖泊沉积物岩芯，开展了花粉与沉积物DNA（sedaDNA）分析，其中花粉数据已提交至PANGAEA数据库（DOI: 10.1594/PANGAEA.922550），上述岩芯当前周边植被类型覆盖从典型苔原到开阔落叶松林的梯度。本研究的核心目标包括：
1. 对比沉积物DNA与花粉数据，探究两种分析方法在俄罗斯北部林线带的植被组成与多样性变化中是否呈现一致的变化模式，或是二者互为补充；
2. 重建南北样带上中全新世至晚全新世的植被组成变化；
3. 利用沉积物DNA数据重建物种丰富度的变化，并探讨其与植被及气候变化的关联。