Seasonal and daily variation of mercury evasion at coastal and off shore sites from the Mediterranean Sea
Seasonal and daily variation of mercury evasion at coastal and off shore sites from the Mediterranean Sea
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DOI：
10.1016/j.marchem.2006.11.003
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发表时间：
2007-03-21
期刊：
影响因子：
3
通讯作者：
Lindqvist, Oliver
中科院分区：
文献类型：
--
作者：
Andersson, Maria E.;Gardfeldt, Katarina;Lindqvist, Oliver
使用两种新开发的技术和手动技术连续测量溶解气态汞（DGM）。连续技术基于水相和气相之间的平衡（DGM = Hg-extr / H'，Hg-extr 是气相中测得的汞浓度，H' 是所需温度下的亨利定律系数）。为了计算地中海每年的汞逃逸量，对 DGM、空气中气态汞总量 (TGM)、水温和风速进行了每日和季节性测量。 2003年8月、2004年3月至4月和2004年10月至11月期间，这些参数的测量是在RV Urania上进行的。 DGM 的连续测量显示沿海和近海地点的浓度存在日间变化，白天的浓度高于夜间。白天和晚上的浓度差异可能高达 130 fM。饱和度直接根据测量结果计算得出，S = Hg-extr / TGM，并且发现不同季节之间存在差异。夏季观察到最高平均饱和度（850%）和最大饱和度变化（600-1150%）。春季表现出最低的变化（260-360%）和最低的平均饱和度（320%）。与夏季游轮相比，秋季的饱和度也存在较大差异（500-1070%），但平均值较低（740%）。这可以用不同季节之间的温差来解释，因为该参数变化最大。使用 Nightingale 等人开发的气体交换模型计算来自海面的通量。 [Nightingale, P.D.、Malin, G.、Law, C.S.、Watson, A.J.、Liss, P. S.、Liddicoat, M.I.、Boutin, J.、Upstill-Goddard, R. C., 2000。使用新型保守和挥发性示踪剂对海气交换参数化进行原位评估。全球生物地球化学循环，14(l):373-387]。不同季节的逃逸率有所不同，秋季逃逸率最高，为24.6 pmol m(-2) h(-1)。夏季数值估计为22.3 pmol m(-2) h(-1)，春季数值为7.6 pmol m(-2) h(-1)。根据这些数据，每年从地中海表面逃逸的物质估计为 77 吨。 (C) 2006 Elsevier B.V. 保留所有权利。
Dissolved gaseous mercury (DGM) was measured continuously using two newly developed techniques and a manual technique. The continuous techniques were based on the equilibrium between the aqueous and gaseous phase (DGM = Hg-extr / H', Hg-extr is the measured mercury concentration in the gas phase, H' is the Henry's Law coefficient at the desired temperature). In order to calculate the annual mercury evasion from the Mediterranean Sea, diurnal and seasonal measurements of DGM, total gaseous mercury in air (TGM), water temperature and wind speed were performed. During August 2003, March-April 2004 and October-November 2004 measurements of these parameters were conducted on board the RV Urania. The continuous measurements of DGM showed a diurnal variation in concentration, at both coastal and off shore sites, with higher concentrations during daytime than nighttime. The concentration difference could be as large as 130 fM between day and night. The degree of saturation was calculated directly from the measurements, S = Hg-extr / TGM and was found to vary between the different seasons. The highest average degree of saturation (850%) and the largest variation in saturation (600-1150%) was observed during the summer. The spring showed the lowest variation (260-360%) and the lowest average degree of saturation (320%). The autumn also showed a large variation in saturation (500-1070%) but a lower average (740%) compared to the summer cruise. This might be explained by the temperature difference between the different seasons, since that parameter varied the most. The flux from the sea surface was calculated using the gas exchange model developed by Nightingale et al. [Nightingale, P.D., Malin, G., Law, C.S., Watson, A.J., Liss, P. S., Liddicoat, M.I., Boutin, J., Upstill-Goddard, R. C., 2000. In situ evaluation of air-sea gas exchange parameterization using novel conservative and volatile tracers. Global Biogeochemical Cycles, 14(l):373-387]. The evasion varied between the different seasons with the highest evasion during the autumn, 24.6 pmol m(-2) h(-1). The summer value was estimated to 22.3 pmol m(-2) h(-1) and the spring to 7.6 pmol m(-2) h(-1). Using this data the yearly evasion from the Mediterranean Sea surface was estimated to 77 tons. (C) 2006 Elsevier B.V. All rights reserved.