Kuss Joachim, Schneider Bernd
Department of Marine Chemistry, Leibniz Institute for Baltic Sea Research (IOW), Rostock-Warnemünde, Germany.
Environ Sci Technol. 2007 Dec 1;41(23):8018-23. doi: 10.1021/es0716251.
The importance of the sea as a sink for atmospheric mercury has been established quantitatively through models based on wet and dry deposition data, but little is known about the release of mercury from sea areas. The concentration of elemental mercury (Hg0) in sea surface water and in the marine atmosphere of the Baltic Sea was measured at high spatial resolution in February, April, July, and November 2006. Wind-speed records and the gas-exchange transfer velocity were then used to calculate Hg0 sea-air fluxes on the basis of Hg0 sea-air concentration differences. Our results show that the spatial resolution of the surface water Hg0 data can be significantly improved by continuous measurements of Hg0 in air equilibrated with water instead of quantitative extraction of Hg0 from seawater samples. A spatial and highly seasonal variability of the Hg0 sea-air flux was thus determined. In winter, the flux was low and changed in direction. In summer, a strong emission flux of up to 150 ng m(-2) day(-1) in the central Baltic Sea was recorded. The total emission of Hg0 from the studied area (235000 km2) was 4300 +/- 1600 kg in 2006 and exceeded deposition estimates.
通过基于干湿沉降数据的模型，已定量确定了海洋作为大气汞汇的重要性，但对于汞从海域的释放情况却知之甚少。于2006年2月、4月、7月和11月，在波罗的海的海表水和海洋大气中，以高空间分辨率对元素汞（Hg0）的浓度进行了测量。随后，利用风速记录和气交换传输速度，基于Hg0海气浓度差异来计算Hg0海气通量。我们的结果表明，相较于从海水样本中定量提取Hg0，通过连续测量与水达到平衡的空气中的Hg0，地表水Hg0数据的空间分辨率可得到显著提高。由此确定了Hg0海气通量的空间和高度季节性变化。冬季，通量较低且方向发生变化。夏季，在波罗的海中部记录到高达150 ng m(-2) 天(-1) 的强排放通量。2006年，研究区域（235000平方公里）的Hg0总排放量为4300 +/- 1600千克，超过了沉降估计值。
