第八届青年地学论坛

Hydrological cycles in Antarctic ice-free regions are closely linked to changes of air temperature, precipitation (snow), evaporation and sea ice. However, paleo-hydrological records over longer timescales and driving mechanism remain elusive in the Ross Sea, East Antarctica. Two microbial mat depositional lacustrine sediment profiles (IIL3 and IIL9) were selected at Inexpressible Island, North Victoria Land, western Ross Sea. We present a new record of pond hydrological cycle using compound-specific hydrogen isotopes over the past 3,200 years. Here we show that the main drivers on the hydrogen isotope composition of lipids in photoautotrophic organisms are lake/pond salinity and water isotopes, which reflects regional evaporation strength. Our results, compared with many records at the studied site, indicate that the strength of evaporation is closely linked with summer air temperature with high salinity to warmer temperatures over the past 3,200 years. Similarities between our hydrological records, El Niño-Southern Oscillation (ENSO) and Southern Annual Mode (SAM) variability indicate that climate in the western Ross Sea is tele connected with the tropical Pacific Ocean. Specifically, during El Niño events, anomalous high-pressure was dominated near the Amundsen Sea, causing greater warm and moisture air transportation into western Ross Sea, vise during La Niña events. We conclude that natural variability in the tropical and sub-tropical played a crucial role in the changes of hydrological in the high latitude of Antarctica. 

East Antarctica; Compound-specific hydrogen isotopes; Evaporative process; Hydrological cycle; Atmosphere circulation