Mercury in surface waters of the open ocean

Journal Article · Tue Sep 01 04:00:00 EDT 1987 · Global Biogeochemical Cycles; (USA)

DOI:https://doi.org/10.1029/GB001i003p00199· OSTI ID:7118988

Gill, G A; Fitzgerald, W F ^[1]

---

1. Connecticut Univ., Groton (USA)

Hg was determined in samples of surface seawater and rainfall from coastal and open ocean areas of the northwest Atlantic and Pacific Oceans. Hg concentrations in surface seawater and open ocean rainfall ranged from 0.5 to 11 pM and 6 to 130 pM, respectively. The fluvial flux of Hg to the open ocean was estimated at 1.7 Gg/yr, using mean concentrations of Hg in rainfall and annual rainfall volume estimates for the major ocean basins. Fluvial input, while difficult to reliably assess, was a less important source of Hg to the ocean. The mean residence time of Hg in the surface mixed layer was calculated at 4-7 years. Surface seawater Hg distributions are markedly influenced by atmospheric sources. Due to an elevated supply of Hg to the northwest Atlantic by rain, higher Hg values were observed in surface seawater in the northwest Atlantic Ocean than at low latitudes in the central North Pacific Ocean. Surface seawater Hg concentrations between coastal New England and the Sargasso Sea do not show the large offshore concentration gradient typical of elements which have relatively large fluvial or coastal sources. Rather, the Hg distribution in this region was similar to that obtained for the atmospherically derived constituents Pb and Pb{sup 210}. Surface seawater Hg measurements in the central Pacific Ocean along 160 degrees W between 20 degrees N and 20 degrees S showed a depression in the equatorial upwelling area. In contrast to the surface distribution in the northwest Atlantic, a pronounced on-shore gradient in seas surface Hg concentration was observed in the Tasman Sea. 51 refs., 6 figs., 7 tabs.

• OSTI ID: 7118988
• Journal Information: Global Biogeochemical Cycles; (USA), Journal Name: Global Biogeochemical Cycles; (USA) Vol. 1:3; ISSN 0886-6236; ISSN GBCYE
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
ATLANTIC OCEAN
ECOLOGICAL CONCENTRATION
ELEMENTS
HYDROGEN COMPOUNDS
MERCURY
METALS
MONITORING
OXYGEN COMPOUNDS
PACIFIC OCEAN
POLLUTION
POLLUTION SOURCES
SEAS
SEAWATER
SURFACE WATERS
UPWELLING
WATER
WATER POLLUTION