Atlantic mercury emission determined from continuous analysis of the elemental mercury sea‐air concentration difference within transects between 50°N and 50°S
Atlantic mercury emission determined from continuous analysis of the elemental mercury sea‐air concentration difference within transects between 50°N and 50°S
复制标题
DOI：
10.1029/2010gb003998
复制
发表时间：
2011-09
影响因子：
5.2
通讯作者：
J. Kuss;C. Zülicke;C. Pohl;B. Schneider
中科院分区：
文献类型：
--
作者：
J. Kuss;C. Zülicke;C. Pohl;B. Schneider
由于挥发性单质汞（Hg0）在大气中的流动性，再加上汞化合物对人类健康和生态系统的有害影响，环境中的汞值得严重关注。据推测，全球大气汞的一个主要来源是海洋排放的汞。然而，可用的用于可靠估计海洋汞排放的Hg0地表水数据很少。在这项研究中，2008年11月在欧洲和南非之间以及2009年4 - 5月在南美和欧洲之间进行了高分辨率地表水和空气中Hg0的测量。在每次巡航中，确定了热带地表水中Hg0的强烈富集，这明显与热带辐合带（ITCZ）的季节变化有关。高的Hg0生成速率常数和实际的低风速共同阻止了Hg0的排放，这可能导致了ITCZ地表水中Hg0的积累。只有考虑到月尺度上的风速变化，热带地区的汞排放才会显著，在这种情况下，观测到的热带地表水中总汞在北部冬季的显著下降可以解释。在中纬度地区，北半球11月和南半球5月的秋季温室气体排放量增加；相反，北部和南部春季的排放量都很低。通过排放汞和下沉颗粒去除地表水中的汞与通过湿沉降和干沉降提供汞相当。
Mercury in the environment deserves serious concern because of the mobility of volatile elemental mercury (Hg0) in the atmosphere, in combination with the harmful effect of Hg compounds on human health and the ecosystem. A major source of global atmospheric mercury is presumed to be oceanic Hg0 emission. However, available Hg0 surface water data to reliably estimate the ocean's mercury emissions are sparse. In this study, high‐resolution surface water and air measurements of Hg0 were carried out between Europe and South Africa in November 2008 and between South America and Europe in April–May 2009. On each cruise a strong enrichment of Hg0 in tropical surface water was determined that apparently followed the seasonal shift of the Intertropical Convergence Zone (ITCZ). A combination of a high Hg0 production rate constant and the actual low wind speeds, which prevented emission, probably caused the accumulation of Hg0 in surface waters of the ITCZ. Hg0 emissions in the tropics were significant only if wind speed variability on a monthly scale was considered, in which case the observed significant decline of total Hg in tropical surface waters during the northern winter could be explained. In the midlatitudes, increased autumn Hg0 emissions were calculated for November in the Northern Hemisphere and for May in the Southern Hemisphere; conversely, emissions were low during both the northern and the southern spring. Mercury removal from surface waters by Hg0 emission and sinking particles was comparable to its supply through wet and dry deposition.