Below-ground carbon stocks and soil properties in the central Lena River Delta, Kurungnakh and Samoylov Islands from 12 permafrost profiles sampled in 2018

Arctic warming increases the degradation of permafrost soils but little is known about floodplain soils and other permafrost soils in the permafrost region. This dataset present soil properties from twelve analyzed cores located in the northeastern Siberian Lena River Delta within the continuous permafrost zone in northern Yakutia, Russia that were sampled in 2018. The cores represent intact yedoma, yedoma thaw slumps, and floodplain profiles. The soil coring and sampling was carried out in August 2018 for a total of 30 soil cores, 35 soil profiles, and 341 sediment samples. First, vegetation and other characteristics of the plots were described. Then, the active layer soils were excavated, described, and sampled with a fixed volume cylinder (250 cm³). Then the permafrost layers were sampled with a modified, snow, ice, and permafrost (SIPRE) auger to a depth of 1 m (core diameter of 7.62 cm) and visually described in their characteristics. Each core was divided into subsamples with 5-10 cm length according to its facies horizons, transported frozen to Alfred Wegener Institute in Potsdam, and stored at -20 °C until analysis. A subset of these sediment samples (n=105 from 12 cores) were later analyzed in the laboratory for physical and chemical properties; this data is presented here. The analysis from these samples includes: water content, dry bulk density, gravimetric ice content, pH, conductivity, total organic carbon content, total inorganic carbon content, total carbon content, total nitrogen content, carbon density, TOC storage, and TN storage. Selected samples were further analyzed for radiocarbon and grain size analysis.

北极变暖加剧了多年冻土土壤（permafrost soils）的退化，但目前学界对泛洪平原土壤及多年冻土区（permafrost region）内其他类型多年冻土土壤的认知仍较为匮乏。本数据集收录了2018年于俄罗斯雅库特北部连续多年冻土带内的西伯利亚勒拿河三角洲东北部采集的12个钻孔的土壤属性数据。所采集的钻孔涵盖完整冰楔假层土（yedoma）、冰楔假层土融滑塌体及泛洪平原剖面。2018年8月，本次研究共完成30个土壤钻孔、35个土壤剖面及341个沉积物样品的采集工作：首先对样地的植被及其他特征进行详细描述；随后采用250 cm³固定体积环刀对活动层土壤进行开挖、特征描述并采样；再使用经改装的雪-冰-多年冻土（SIPRE）钻机，以7.62 cm的钻杆直径进行采样，最大采样深度达1 m，并对钻孔的岩性特征进行目视描述。每个钻孔依据其岩相地层划分为5~10 cm长度的子样品，冷冻运输至位于波茨坦的阿尔弗雷德·魏格纳研究所（Alfred Wegener Institute），并保存于-20 ℃环境中直至开展实验室分析。其中，从12个钻孔中选取的105个沉积物样品子集，后续在实验室完成了理化性质分析，本数据集即呈现该部分分析结果。本次分析涵盖的指标包括：含水量、干容重、重量法冰含量、pH值、电导率、总有机碳含量、总无机碳含量、总碳含量、总氮含量、碳密度、总有机碳储量及总氮储量。另有部分样品进一步开展了放射性碳测年与粒度分析。