报告一：沉积物有机分子组成揭示冰川消退对青藏高原生态影响
报告二：黑色页岩中硝酸根O17异常
时 间：4月20日（周四）中午12：30
地 点：16教学楼221报告厅
报告一：沉积物有机分子组成揭示冰川消退对青藏高原生态影响
Sedimentary organic molecular compositions reveal the influence of glacier retreat on ecology on the Tibetan Plateau
主讲人：2019级博士 史思伟
摘 要：
全球变暖和冰川退缩对自然生态系统的结构和功能产生了重大影响。然而，关于冰川退缩如何影响高海拔地区生态系统的长期演变仍然知之甚少。本研究基于详细的沉积物有机质分子组成和多种地球化学指标研究了冰川消退对青藏高原东南部普莫雍错流域植被及湖沼生产力的可能影响。随着近现代全球升温及冰川消退，湖泊沉积物中陆地植被和土壤衍生的大分子量化合物（如维管植物源多酚化合物、高度不饱和酚类化合物和稠环芳烃）的比例逐步增加，说明气候暖化导致被冰川覆盖的陆地重新暴露，冰消区植被逐渐恢复。~1870AD以来，湖泊沉积物中含氮化合物（如CHNO）相对丰度和叶绿素衍生物含量均有所增加，表明冰川退缩后增强的流域风化和陆地养分输入提高了下游湖沼生产力。我们的研究结果暗示，未来持续的全球变暖和冰川消退可能会进一步促进青藏高原植被扩张并提高湖沼生产力。
Global warming and glacier retreat have significant impacts on the structure and function of natural ecosystems. However, little is known about how glacier retreat affects the long-term evolution of ecosystem at high-altitude regions. In this study, we explored the possible effects of glacier retreat on catchment vegetation and lake productivity in Lake Puma Yumco, southeastern Tibetan Plateau, based on detailed organic molecular compositions determined by ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and on various sedimentary geochemical indicators. Accompanying with modern global warming and glacier shrinkage, the relative abundance of soil- and vegetation-derived large molecular compounds (e.g., vascular plant-derived polyphenols, highly unsaturated and phenolic compounds, and condensed aromatics) increased gradually in lake sediments, suggesting that ice-covered land was exposed under warming condition, and gradually revegetation occurred. Both increases in relative abundance of nitrogen-containing compounds (e.g., CHNO) and chlorophyll derivative contents in the lake sediments were observed since ~1870 AD, suggesting that stronger catchment weathering and increasing terrestrial nutrient loads enhanced the downstream lake productivity after glacier retreat. Our results imply that continued global warming and alpine glacier retreat in the future may further promote vegetation expansion and increases in lake productivity on the Tibetan Plateau.
报告二：黑色页岩中硝酸根O17异常
主讲人：2020级博士 范伟国
摘 要：
本报告将介绍黑色页岩硝酸根提取方法，同位素定量评估框架以及潜在的古气候指示意义。
