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首页> 外文学位 >Distribution and Partitioning of Mercury in the Arctic Cryosphere: Transport Across Snow-Sea Ice-Water Interfaces in the Western Arctic Ocean
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Distribution and Partitioning of Mercury in the Arctic Cryosphere: Transport Across Snow-Sea Ice-Water Interfaces in the Western Arctic Ocean

机译：北极冰层中汞的分布和分配：在北冰洋西部跨雪海冰水界面的运输

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摘要

The high toxicity and ability to be transported over long distances and biomagnify up food chains have earned Mercury (Hg) recognition as a contaminant of global concern. The Arctic region is particularly vulnerable to Hg with high levels of Hg being detected in marine mammals. The importance of the cryosphere, especially sea ice, has often been neglected in considerations of the extent to which atmospherically derived Hg impinges on the underlying marine system. This thesis reports the first systematic study of Hg transport in the Arctic cryosphere (sea ice, brine, snow, and melt ponds) conducted in the Amundsen Gulf from February to June 2008. Hg concentrations in bulk first-year sea ice were generally low (0.5--4 ng L-1), with the highest concentration in the surface granular ice layer. The highest concentrations of Hg were found in sea ice brine (up to 70 ng L-1). Atmospheric mercury depletion events (AMDEs) appear not to be an important factor in determining Hg in sea ice, with the exception of in frost flowers. Evidence of Hg accumulation during melt--refreezing cycles is seen in multi-year ice. Significant impact of AMDEs is observed on Hg concentrations in snow. Rates of deposition of atmospheric Hg ranged from 200--784 ng m-2 into the top 1 cm of snow. Although photo reduction and reemission to the atmosphere does occur, a considerable fraction of deposited Hg is retained in the snowpack due to subsequent burial. At one station it is estimated that less than 50% of the deposited Hg is re-emitted to the atmosphere. It is suggested that in the Beaufort Sea, where AMDEs occur frequently due to dynamic nature of the sea ice environment, a larger than suspected portion of atmospherically deposited Hg can be retained in the snowpack and enter the underlying marine system upon melt later in the season.
机译：高毒性和长距离运输能力以及生物放大食物链的能力已使汞（Hg）被公认为全球关注的污染物。北极地区特别容易受到汞污染，在海洋哺乳动物中检测到高水平的汞。考虑到大气中汞对基础海洋系统的影响程度，冰冻圈尤其是海冰的重要性常常被忽略。本论文报告了从2008年2月至2008年6月在阿蒙森海湾进行的北极冰冻圈（海冰，盐水，积雪和融化池塘）中的汞运输的首次系统研究。第一年散装的第一年海冰中的汞浓度普遍较低（ 0.5--4 ng L-1），在表面颗粒冰层中浓度最高。在海冰盐水（最高70 ng L-1）中发现了最高的Hg浓度。除霜花外，大气汞消耗事件（AMDE）似乎不是确定海冰中汞的重要因素。在多年的冰中可以看到在融化-再冰冻循环中汞积累的证据。观察到AMDE对雪中汞浓度有显着影响。大气Hg在最高1厘米的积雪中的沉积速率为200--784 ng m-2。尽管确实发生了光的还原和释放到大气中，但是由于随后的埋葬，相当一部分沉积的Hg保留在积雪堆中。在一个站点，据估计，不到50％的汞沉积物会重新排放到大气中。建议在波弗特海中，由于海冰环境的动态性质而经常发生AMDE，在季节后期融化后，大气中沉积的Hg可能会大于怀疑的一部分，并进入下层海洋系统。 。

著录项

  • 作者

    Chaulk, Amanda Holly.;

  • 作者单位

    University of Manitoba (Canada).;

  • 授予单位 University of Manitoba (Canada).;
  • 学科 Environmental science.;Atmospheric chemistry.;Chemical oceanography.
  • 学位 M.Sc.
  • 年度 2011
  • 页码 131 p.
  • 总页数 131
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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