[M-IS05] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

[MIS05-P05] Lake Environmental change since little ice age in Antarctic ice-free area, Skarvsnes, East Antarctica

*Kota Katsuki¹, Yuito Kamada², Hanna Wakabayashi², Moemi Kawagishi², Akira Tsujimoto⁶, Yusuke Suganuma³, Daisuke Shibata⁴, Moto Kawamata⁵ (1.Estuary Research Center, Shimane University, 2.Interdisciplinary Faculty of Science and Engineering, Shimane University, 3.National Institute of Polar Research, 4.Shimoda Marine Research Center, Tsukuba Univeristy , 5.The Graduate University for Advanced Studies, 6.Faculty of Education, Shimane University)

Keywords:Antactica, Ice free area, Diatom, Paleoenvironment

Recently, there has been concern over the rapid melting of the Antarctic ice sheet due to increases in air and sea temperatures. Then, researches about instrumental and satellite ice sheet and ocean observations have been eagerly studied in recent. Furthermore, geological research for understanding the ice sheet melting history since the last glacial maximum has also been actively. On the other hand, unfortunately, there has been little research on the history of ice sheet changes and its effect on Antarctic lake ecosystems over the past few hundred years, when the effects of anthropogenic warming have become more pronounced. Therefore, we investigate the changes of Antarctic lake ecosystem since the little ice age based on the lowland and glacial lakes which may have the relatively high sedimentation rate. It is well used diatom remains for reconstructing the paleo lake ecosystem and environment. In Antarctic region, diatom distributions and ecology were reported from the fresh water and saline lake in ice free areas and outer sea, however it was rare reports for coast and gulf. In this study, the diatom distributions along the coast of Gulfs of Osen and Torinosu in Skalvsnes were investigated at first, then the diatom remains in sediment of the small lakes along the Gulf of Osen was analyzed. Skalvsnes is the one of the ice free area along the Soya Coast in East Antarctica. Lake Koike is the small fresh water lake, and fresh water diatom taxa has been dominated in the sediment. The number of diatom valves in the sediment has been highly fluctuated, and the peaks of diatom valves occur when the marine diatom increased. It probably means that the austral summer high tide event has been occurred in cyclic.