Air-sea exchange of volatile mercury in the North Atlantic Ocean
Journal article, 2011
Part of the Beringia 2005 expedition covered the North Atlantic Ocean. During this passage, dissolved gaseous mercury (DGHg) in seawater and atmospheric concentrations of total gaseous mercury (TGHg), carbon monoxide (CO), and ozone (O-3) were measured continuously at high resolution. In addition, meteorological parameters such as wind speed and water temperature were measured continuously by the ship's meteorological instrumentation. The DGHg concentration was measured using a continuous equilibrium system where the elemental mercury in the sea water was equilibrated with a stream of gas. The DGHg concentration was calculated using DGHg=Hg-eq/k(H), where Hg-eq is the concentration of elemental mercury in the equilibrated air and k(H), is the dimensionless Henry's law constant. The degree of saturation was determined directly from the measurements S = Hg-eq/TGHg. The water sampled had an average DGHg concentration of 58 +/- 10 fM and the average TGHg concentration was determined to 1.7 +/- 0.1 ng m(-3). The water sampled was under- and super-saturated with respect to elemental mercury covering a large range of saturation of 70 to 230% resulting in an average degree of saturation of 150 +/- 30%. Therefore, both evasion and deposition of elemental mercury were observed in the sampled water. In the light of the average flux, 2.1 +/- 1.8 pmol m(-2) h(-1), it is concluded that mostly evasion occured during the sampling period. (C) 2011 Elsevier B.V. All rights reserved.
TGHg
surface waters
mediterranean sea
In situ measurements
gas-exchange
elemental mercury
Gas exchange
DGHg
Flux
coastal
Water measurements
Mercury
North Atlantic
Air measurements
atmospheric mercury
equatorial atlantic
Ocean
term measurements
humic substances
dissolved gaseous mercury
seawater
Author
Maria Andersson
University of Gothenburg
J. Sommar
Chinese Academy of Sciences
Katarina Gårdfeldt
Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry
S. Jutterstrom
University of Gothenburg
Marine Chemistry
0304-4203 (ISSN)
Vol. 125 1-4 1-7Subject Categories
Chemical Sciences
DOI
10.1016/j.marchem.2011.01.005