青藏高原冰川氮记录研究进展

近年来，青藏高原冰川持续退缩，显著影响区域气候与生物地球化学循环。作为重要的营养元素，氮在生态系统中的循环备受关注。冰川中含氮化合物的迁移转化是冰冻圈地区氮循环的重要环节。基于青藏高原地区冰川氮记录研究，综述了近年来冰芯氮记录的历史变化，指出不同区域的变化趋势存在差异，认为一定程度上受亚洲地区人类活动排放污染物的影响。通过全面的雪冰氮（总氮以及NO₃^-、NH₄⁺等）数据收集与分析，阐明了冰川雪冰中可溶无机氮北高南低的整体空间分布特征。利用冰川物质平衡数据，评估了气候变化背景下青藏高原冰川氮的释放量，结果表明：可溶无机氮年均释放量可达4 700 t?a^-1以上。基于目前的研究与认识，提出了冰冻圈地区冰川雪冰氮研究的薄弱环节并进行了展望。在未来的研究中特别关注有机氮以及氮同位素的研究，加强冰川氮释放迁移对青藏高原冰冻圈地区氮循环的影响研究。

Research progress on nitrogen records from glaciers in the Tibetan Plateau

The glaciers in the Tibetan Plateau has been experiencing rapid retreat during recent decades， which may significantly influence the regional climate change and biogeochemical cycles. As an important nutrient matter， the role of nitrogen in the ecosystems has caused many attentions. The migration and transformation of nitrogen components from glaciers are the important linkage of nitrogen cycle in cryospheric regions. Based on the glacier nitrogen （including total dissolved nitrogen， NO₃^-， NH₄⁺） studies in the Tibetan Plateau， this paper synthesized the different trends of historical nitrogen variations from ice cores in different regions， which indicated the potential impact of anthropogenic emissions from Asia. We also illustrated the spatial distribution features of dissolved inorganic nitrogen from glaciers， which showed high level in the northern Tibetan Plateau， and vice versa. Based on the collected data of glacier mass balance， we estimated the export of nitrogen from Tibetan glaciers under climate change. The results revealed that the annual average dissolved inorganic nitrogen can reach to about 4 700 t?a^-1. Upon to the present studies and understandings， we also provided the perspectives on further research on glacial nitrogen. In future， studies on the dissolved organic nitrogen and nitrogen isotopes should be strengthened. The transport and transform of nitrogen from the glacier melt and their impact on the nitrogen cycle in the cryospheric regions of the Tibetan Plateau should also be focused.