Cryospheric chemistry of mercury in sea ice

汞是一种已知的发育神经毒素。近几十年来，它在加拿大北冰洋的海洋哺乳动物中高度集中，这引起了人们对这些动物和将这些动物作为传统饮食一部分的北方人的健康的重大担忧。虽然监测数据表明，不断变化的海冰环境可能在北极海洋生态系统中汞的生物积累方面发挥了重要作用，但由于缺乏对海冰环境中发生的基本物理化学过程的了解，目前几乎不可能解释这种观测数据的意义和影响。这在很大程度上是由于普遍缺乏对零下温度下的水和水化学的了解。为了填补在物理和环境化学方面的这一重大知识空白，将在实验室、中层和现场尺度上进行实验研究，以确定控制海冰环境中汞转化的零下温度物理化学过程，特别侧重于在海冰表面和海冰卤水中发生的反应。然后，热力学数据将被纳入FREZCHEM等化学平衡模型和GEOS-CHEM等化学运输模型，以模拟北极海洋生态系统中汞的生物积累将如何应对加拿大北极地区预计的气候变化和经济发展。由于冰冻圈化学和海冰是新的科学前沿，预计这项研究将在零下温度下的非均相反应途径和机制以及与天然或工程冷系统的采样、分析和建模有关的技术开发方面取得重大发现。

Mercury is a known developmental neurotoxin. Its high concentration in marine mammals in Canadian Arctic Ocean in recent decades has raised major concerns over the health of these animals and the Northerners who consume these animals as part of their traditional diets. Although monitoring data have suggested that a changing sea ice environment may have been playing a major role in mercury bioaccumulation in the Arctic marine ecosystem, interpreting the significance and implication of such observational data is almost impossible at this time due to the lack of understanding of fundamental physicochemical processes occurring in the sea ice environment. This is largely attributable to a general lack of understanding of aqueous and aquatic chemistry at subzero temperatures. To fill in this major knowledge gap in physical and environmental chemistry, experimental studies at laboratory, mesocosm and field scales will be carried out to characterize subzero-temperature physicochemical processes governing the transformation of Hg in the sea ice environment, with a particular focus on reactions occurring at the sea ice surface and in sea ice brine. The thermodynamic data will then be incorporated into chemical equilibrium models such as FREZCHEM and chemical transport model such as GEOS-CHEM to model how mercury bioaccumulation in the Arctic marine ecosystem would respond to the projected climate change and economic development in the Canadian Arctic. As cryospheric chemistry and sea ice are new scientific frontiers, this study is anticipated to result in major discoveries in heterogeneous reaction pathways and mechanisms at subzero temperatures, as well as in technological development related to sampling, analysis and modeling of natural or engineered cold systems.