关键词: 东南极, 莫愁湖, 大明湖, 沉积物, 生物硅, 初级生产力

Abstract:

Two sediment cores, collected from Mochou Lake and Daming Lake in the area of Antarctic Zhongshan Station, were analyzed for some biogeochemical parameters such as biogenic silica, organic matter etc. Based on the synthetically comparative researches, we focused on the potential application of biogenic silica on the reconstruction of ecoenvironmental changes recorded in the east Antarctica lake sediments. The results showed that a large number of diatoms were well preserved in the freshwater lake sediments in east Antarctic, and the concentrations of biogenic silica displayed notable fluctuations versus depth. The contents of organic matter etc had almost consistent vertical change patterns with biogentic silica, reflecting their common ecoenvironmental implications. The low levels of above biochemical proxies reflected the reduction of lake algal production, corresponding to the decreased lake primary productivity. Overall, for the fragile lake ecosystem and exposed bedrock around in East Antarctic, the contents of biogenic silica in the sediments can sensitively indicate the evolution of palaeolake primary productivity, and thus it is an ideal proxy for the reconstruction of past eco-environmental changes recorded in the east Antarctic lacustrine sediments.

Key words: East Antarctica, Mochou Lake, Daming Lake, sediments, biogenic silica, primary productivity