Taxonomic compositions of chironomids and results of chironomid-based PCA of sediment core 11-CH-12

We studied a sediment core from the lake Khatanga-12 (Taimyr Peninsula, Krasnoyarsk region). The core is 131.5 cm long and covers a period of sedimentation of 7100 years. In this study we made a chironomid analysis and a qualitative reconstruction of paleoecological development of the region and quantitative reconstruction of mean-July air temperature and the water depth in the lake using Russian regional statistical chironomid-based climate-inference models (Nazarova et.al., 2008, 2011, 2015). The lake was formed during the mid-Holocene warming as a result of thermokarst processes. Development of the lake ecosystem Khatanga - 12 in various stages was influenced by climatic factors and cryolitogenic processes. Mid-Holocene warming around 7100 - 6500 calibrated years BP activated thermokarst processes and resulted in formation of the lake basin. Cooling was reconstructed between 6500 and 4500 cal. years BP. The sediments of the lake have been formed by the erosion processes of the lake banks. After 2500 cal. BP reconstructed conditions are close to modern.本研究针对位于克拉斯诺亚尔斯克地区泰梅尔半岛的哈坦加-12湖（Khatanga-12）的沉积物岩芯开展分析。该岩芯总长131.5 cm，沉积记录跨度达7100年。本研究借助基于俄罗斯区域统计摇蚊（chironomid）的气候推断模型（Nazarova等，2008、2011、2015），完成了摇蚊分析，对该区域的古生态演化进行了定性重建，并定量重建了湖区7月平均气温与湖水水深。该湖形成于全新世中期暖期，由热融喀斯特（thermokarst）作用塑造而成。哈坦加-12湖生态系统的各演化阶段均受气候因素与冻融成因（cryolitogenic）作用的共同影响。约7100~6500校准年BP的全新世中期暖期激活了热融喀斯特作用，进而形成湖盆；6500~4500校准年BP期间被重建为降温阶段。湖区沉积物由湖岸侵蚀作用形成。2500校准年BP以来，重建的湖区环境与现代环境基本一致。