Holocene lake response to glacier and catchment changes on the eastern Tibetan Plateau from quantitative conductivity reconstructions based on sedaDNA-derived macrophyte records

作者：Wenjia Li, Xianyong Cao, Kathleen R. Stoof‐Leichsenring, Xiaohuan Hou, Shi‐Yong Yu, Fang Tian, Ulrike Herzschuh · 发表于：Quaternary Science Reviews · 年份：2024 · DOI：10.1016/j.quascirev.2024.108806 · 被引用次数：7 · 研究领域：Geology and Paleoclimatology Research、Cryospheric studies and observations、Climate change and permafrost

Understanding the response of long-term aquatic environmental changes in lakes to ongoing climate change and human activities is key to forecasting future lake conditions. In this study, we infer the Holocene limnological changes in Emu Co, a proglacial lake in Nianbaoyuze on the eastern Tibetan Plateau, from sedimentary ancient DNA (sedaDNA) data, and palynomorph, element, lithological, and grain-size analyses. We developed a transfer function based on Siberia and Tibet/China surface sedimentary DNA and applied it to Emu Co sedaDNA to trace lake conductivity changes. The results show that the conductivity of Emu Co was high during 12.6−9.7 cal ka BP, often surpassing 1000 μs cm−1, driven by elevated summer solar radiation. The freshwater influx from glacial meltwater and precipitation, however, reduced the lake's conductivity as the climate warmed and humidified. This led to a decrease in the abundance of taxa characterised by high conductivity. Freshwater pulses, triggered by climatic fluctuations, likely led to significant variations in conductivity within the overarching downward trend. By 8 cal. ka BP, lake recharge conditions stabilised and conductivity reached a lower level of ∼70 μs cm−1. The warm and humid mid-Holocene (8−5 cal. ka BP) provided suitable habitat conditions for many submerged freshwater taxa. After 5 cal. ka BP, the growth of submerged taxa was restricted, as indicated by a shift from asexual to sexual reproduction in macrophytes, likely in response to...