全球冰川径流中硅的研究进展

A review of bioavailable silica from glacial runoff globally

硅(Si)是硅藻等海洋生物必需的营养元素,在海洋生态系统和碳循环方面扮演着重要角色。在全球变暖背景下,冰川加速消融,融水径流量快速增加,流域硅酸盐风化作用逐渐增强,导致大量Si元素随着融水释放出来并进入下游,很可能影响陆地与海洋生态系统生产力、碳循环并反馈气候变化。当前与冰川消融有关的Si释放及其影响研究已成为国际热点科学问题之一。通过回顾冰川径流中Si浓度及其δ^(30)Si的最新研究成果,分析了Si浓度的空间变化特征,发现冰川径流的Si浓度受采样方法、径流量、基岩特征等因子的共同影响。在总结该领域现存问题的基础上,认为未来急需加强冰川径流Si的野外监测,综合利用多种同位素手段来厘清冰川径流Si的迁移转化过程和输移规律,评估因冰川消融而进入下游生态系统的Si通量,进而为冰川Si的生态及气候影响评估提供科学指导。

Silicon(Si)is an essential nutrient for many marine organisms,such as diatoms,and plays an important role in marine ecosystem as well as carbon cycles. Under the background of global warming,the runoff of meltwater increases rapidly with the accelerated melting of glaciers. Meanwhile,the silicate weathering gradually increases,leading to the release of a large number of Si elements with meltwater and into the downstream,which may affect the primary productivity of marine and lake ecosystems,the global carbon cycle and climate change. Recently,the research of Si related to glacier retreat has become one of the hot scientific issues globally in the background of global climate warming. In addition,we summarized the latest research achievements of Si concentrations and its δ^(30)Si in glaciers,ice sheets and iceberg sources,analyzed the spatial variation characteristics of the Si concentration,found that the Si concentration of glacial runoff is affected by the sampling method,runoff,bedrock characteristics and other factors. Based on summarizing the existing problems in this field,it’s necessary to strengthen the field monitoring,and comprehensively utilize various isotopes method to clarify the transformation process of Si in glacial runoff in the future. Then,it is also important to assess Si fluxes into the downstream ecosystem because of melting glaciers,and thus provide scientific guidance for the significance of glacier Si assessment.