Permafrost-thaw lake development in Central Yakutia: sedimentary ancient DNA and element analyses from a Holocene sediment record

Abstract In Central Yakutia (Siberia) livelihoods of local communities depend on alaas (thermokarst depression) landscapes and the lakes within. Development dynamics these are closely connected to climate change, permafrost thawing, catchment conditions, land use. To reconstruct lake development throughout Holocene we analyze sedimentary ancient DNA (sedaDNA) biogeochemistry from a sediment core Lake Satagay, spanning last c. 10,800 calibrated years before present (cal yrs BP). SedaDNA diatoms macrophytes microfossil diatom analysis reveal formation earlier than 10,700 cal BP. The sedaDNA approach detected 42 amplicon sequence variants (ASVs) taxa, one ASV Eustigmatophyceae ( Nannochloropsis ), 12 ASVs macrophytes. We relate macrophyte community changes climate-driven shifts in water level mineral organic input, which result variable conductivity, in-lake productivity, deposition. detect higher conductivity Early (c. 10,700–7000 BP) compared other periods, supported by dominance Stephanodiscus sp. Stuckenia pectinata . Further warming towards Mid-Holocene (7000–4700 led shallowing an increase submerged Ceratophyllum, decline planktonic diatoms. Late 4700 BP–present) stable shallow conditions confirmed small fragilarioid staurosiroid dominating lake. Satagay has not yet reached final stage development, but satellite imagery shows intensification anthropogenic use, combination with future will likely rapid desiccation