XRF scans of sediment core PG1341 from Lake Lama in northern-central Siberia

The dataset contains the XRF scanning data of the sediment core segments for Lake Lama (core PG1341) from arctic Siberia. The data were measured using an Itrax core scanner (Cox Analytical Systems, Sweden) equipped with a Cr‐tube and a silicon-drift detector (SDD) in combination with a multi‐channel analyser

Geochemistry data from sediment core 16-KP-04-L19B, Lake Rauchuagytgyn, expedition to Chukotka 2016, Russian Arctic

These dataset contains multi proxy data from short sediment core 16-KP-04-L19B obtained from Arctic glacial lake Rauchuagytgyn (N 67.7888, E 168.7380) by gravity coring during the Chukotka 2018 expedition (Siberia). We provide original count data of diatom species from 20 samples along a ca. 10.5 cm interval in the sediment core, next to organic carbon, nitrogen, and mercury concentrations. The data sets provides, calculated from the original data, estimated accumulation rates for diatom valves (diatom accumulation rate, DAR), organic carbon (organic carbon accumulation rates, OCAR), and mercury (Hg accumulation rates, HgAR)

Diatom sequences

The Arctic treeline ecotone is characterized by a steep vegetation gradient from arctic tundra to northerntaiga forests, which is thought to influence the water chemistry of thermokarst lakes in this region.Environmentally sensitive diatoms respond to such ecological changes in terms of variation in diatomdiversity and richness, which so far has only been documented by microscopic surveys. We applied nextgenerationsequencing to analyse the diatom composition of lake sediment DNA extracted from 32 lakesacross the treeline in the Khatanga region, Siberia, using a short fragment of the rbcL chloroplast gene as agenetic barcode. We compared diatom richness and diversity obtained from the genetic approach withdiatom counts from traditional microscopic analysis. Both datasets were employed to investigate diversityand relationships with environmental variables, using ordination methods. After effective filtering of theraw data, the two methods gave similar results for diatom richness and composition at the genus level(DNA 12 taxa; morphology 19 taxa), even though there was a much higher absolute number of sequencesobtained per genetic sample (median 50,278), compared with microscopic counts (median 426). Dissolvedorganic carbon explained the highest percentage of variance in both datasets (14.2 % DNA; 18.7 %morphology), reflecting the compositional turnover of diatom assemblages along the tundra-taigatransition. Differences between the two approaches are mostly a consequence of the filtering process ofgenetic data and limitations of genetic references in the database, which restricted the determination ofgenetically identified sequence types to the genus level. The morphological approach, however, allowedidentifications mostly to species level, which permits better ecological interpretation of the diatom data.Nevertheless, because of a rapidly increasing reference database, the genetic approach with sediment DNAwill, in the future, enable reliable investigations of diatom composition from lake sediments that will havepotential applications in both paleoecology and environmental monitoring

Diatom species from sediment core 16-KP-04-L19B, Lake Rauchuagytgyn, expedition to Chukotka 2016, Russian Arctic

These dataset contains multi proxy data from short sediment core 16-KP-04-L19B obtained from Arctic glacial lake Rauchuagytgyn (N 67.7888, E 168.7380) by gravity coring during the Chukotka 2018 expedition (Siberia). We provide original count data of diatom species from 20 samples along a ca. 10.5 cm interval in the sediment core, next to organic carbon, nitrogen, and mercury concentrations. The data sets provides, calculated from the original data, estimated accumulation rates for diatom valves (diatom accumulation rate, DAR), organic carbon (organic carbon accumulation rates, OCAR), and mercury (Hg accumulation rates, HgAR)

Updated age-depth model of sediment core PG1341 from Lake Lama in northern-central Siberia

Here we provide the updated age-depth model of sediment cores for Lake Lama (core PG1341) from arctic Siberia. The model provides the temporal information for a project on sedimentary ancient DNA shotgun sequencing (von Hippel et al., submitted). This dataset comprises the updated age-depth model for Lake Lama (Taymyr peninsula), based on the Accelerator Mass Spectrometry radiocarbon dating of 19 samples from the sediment core PG1341 (von Hippel et al., 2022) with the additional use of two dated woody remains from Andreev et al. (2004). The age-depth model was established using the R package 'Bacon', based on the IntCal13 calibration curve and dates back 23.000 years. An additional overlap of 145 cm was calculated between the core segments 5 and 6. This recalculation is based on the TOC data and magnetic susceptibility measured by Andreev et al. (2004). The dataset is the output of the bacon run and contains information about the depth of the sediment core and the corresponding minimum, maximum, median, and mean ages in calibrated years ka BP

210Pb and 137Cs dating data from sediment core 16-KP-04-L19B, Lake Rauchuagytgyn, expedition to Chukotka 2016, Russian Arctic

These dataset contains multi proxy data from short sediment core 16-KP-04-L19B obtained from Arctic glacial lake Rauchuagytgyn (N 67.7888, E 168.7380) by gravity coring during the Chukotka 2018 expedition (Siberia). We provide original count data of diatom species from 20 samples along a ca. 10.5 cm interval in the sediment core, next to organic carbon, nitrogen, and mercury concentrations. The data sets provides, calculated from the original data, estimated accumulation rates for diatom valves (diatom accumulation rate, DAR), organic carbon (organic carbon accumulation rates, OCAR), and mercury (Hg accumulation rates, HgAR)

Accumulation rates from sediment core 16-KP-04-L19B, Lake Rauchuagytgyn, expedition to Chukotka 2016, Russian Arctic

These dataset contains multi proxy data from short sediment core 16-KP-04-L19B obtained from Arctic glacial lake Rauchuagytgyn (N 67.7888, E 168.7380) by gravity coring during the Chukotka 2018 expedition (Siberia). We provide original count data of diatom species from 20 samples along a ca. 10.5 cm interval in the sediment core, next to organic carbon, nitrogen, and mercury concentrations. The data sets provides, calculated from the original data, estimated accumulation rates for diatom valves (diatom accumulation rate, DAR), organic carbon (organic carbon accumulation rates, OCAR), and mercury (Hg accumulation rates, HgAR)