关键词: 种植年限, 线虫群落, 微生物群落, 多样性指数, 六盘山, 朝那湫, 磁化率, 环境意义

Abstract: In the research of paleoclimate of lacustrine sediments, higher magnetic susceptibility (MS) value indicates stronger erosion and load capacity of surface runoff, and infects more precipitation and humid climate indirectly. On the contrary, lower MS value indicates weaker erosion and load capacity of surface runoff, and infects less precipitation and arid climate indirectly. We identified the environmental indication of MS using multiproxy indices retrieved from sediments in Lake Chaonaqiu in Loess Plateau. The results correlated well with the records from tree-rings in neighboring regions, and showed that higher MS values indicate weaker erosion and load capacity of surface runoff and that lower MS values indicate stronger erosion and load capacity of surface runoff. The environmental indication significance of lake sediment MS is multi-solvent, due to the complex sedimentary environment. This is mainly determined by the bedrock, vegetation cover, and rainfall pattern of the basin. Therefore, various factors affecting MS should be fully considered in different lakes and combined with other indicators for comprehensive identification.

Key words: diversity index, nematode community, cultivation duration, microbial community, Liupan Mountain, Lake Chaonaqiu, magnetic susceptibility, environmental implication.