关键词: East Antarctica, Lacustrine sediments, BSi, Palaeo-primary productivity, Organic matter

Abstract:

We collected two lake sediment cores (MC and DM) from East Antarctic, and analyzed biogenic silica and other biogeochemical parameters (organic matter, C, N, S, H etc). Based on the synthetically comparative research, we focused on the potential application of biogenic silica (BSi) on the reconstruction of pa-laeo-primary productivity in the East Antarctica lakes. The analytical results showed that a large number of diatoms were well preserved in the freshwater lake sediments, and the concentrations of biogenic silica dis-played notable fluctuations versus depth. The content of biogenic silica had almost consistent pro-file-versus-depth change pattern with organic matter, reflecting their common eco-environmental implications. The low levels of BSi and organic matter indicated the reduction of lake algal production, corresponding to the decreased lake primary productivity. Due to the fragile ecosystem and few contribution of terrestrial organic matter in the East Antarctic lakes, the contents of biogenic silica in the lacustrine sediments can sensitively indicated the evolutional history of palaeo-primary productivity. Overall, BSi is an ideal proxy for the recon-struction of past eco-environmental changes recorded in the lacustrine sediments on East Antarctica.

Key words: East Antarctica, Lacustrine sediments, BSi, Palaeo-primary productivity, Organic matter