You are here:
PRODUCTION AND LOSS OF DISSOLVED GASEOUS MERCURY IN COASTAL SEAWATER (R824778)
Citation:
Amyot, M., G. A. Gill, AND F. M. Morel. PRODUCTION AND LOSS OF DISSOLVED GASEOUS MERCURY IN COASTAL SEAWATER (R824778). ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 31:3606-3611, (1997).
Description:
The formation of dissolved gaseous mercury (DGM, mainly
composed of elemental mercury, Hg0) in the surface
ocean
and its subsequent removal through volatilization is an
important component of the global mercury (Hg) cycle.
We studied DGM production and loss in the coastal
waters
of the Gulf of Mexico using 4-26 h in situ
incubation
experiments. DGM production was only induced in the
presence of sunlight. Once produced, DGM was rapidly
lost
from solution (with a first order rate constant of k =
0.1
h-1), apparently as a result of oxidation.
Furthermore, labora
tory experiments showed that dissolved gaseous Hg0
could
be rapidly oxidized in the presence of chloride. In
the
field, most DGM production (about 60%) was associated
with
the dissolved and colloidal Hg(II) phases. Spiking
of
samples with inorganic Hg(II) prior to in situ
incubation
greatly increased DGM production rates, suggesting that
photoreducible Hg(II) complexes were limiting DGM
production. Diurnally, DGM seems to be formed through
photoproduction in the morning; DGM production halts
when substrate is exhausted, and DGM levels decrease
afterwards, presumably by oxidation of
Hg0.