Vertical mercury distributions in the oceans

Journal Article · Wed Jun 01 04:00:00 EDT 1988 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(88)90240-2· OSTI ID:5510522

Gill, G A; Fitzgerald, W F ^[1]

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1. Univ. of Connecticut, Groton (USA)

The vertical distribution of mercury (Hg) was determined at coastal and open ocean sites in the northwest Atlantic and Pacific Oceans. Reliable and diagnostic Hg distribution were obtained, permitting major processes governing the marine biogeochemistry of Hg to be identified. The northwest Atlantic near Bermuda showed surface water Hg concentrations near 4 pM, a maximum of 10 pM within the main thermocline, and concentrations less than or equal to surface water values below the depth of the maximum. The maximum appears to result from lateral transport of Hg enriched waters from higher latitudes. In the central North Pacific, surface waters (to 940 m) were slightly elevated (1.9 {plus minus} 0.7 pM) compared to deeper waters (1.4 {plus minus} 0.4 pM), but on thermocline Hg maximum was observed. At similar depths, Hg concentrations near Bermuda were elevated compared to the central North Pacific Ocean. The authors hypothesize that the source of this Hg comes from diagenetic reactions in oxic margin sediments, releasing dissolved Hg to overlying water. Geochemical steady-state box modeling arguments predict a relatively short ({approximately}350 years) mean residence time for Hg in the oceans, demonstrating the reactive nature of Hg in seawater and precluding significant involvement in nutrient-type recycling. Mercury's distributional features and reactive nature suggest that interaction of Hg with settling particulate matter and margin sediments play important roles in regulating oceanic Hg concentrations. Oceanic Hg distributions are governed by an external cycling process, in which water column distributions reflect a rapid competition between the magnitude of the input source and the intensity of the (water column) removal process.

• OSTI ID: 5510522
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 52:6; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580400* -- Geochemistry-- (-1989)
ACTIVATION ENERGY
ATLANTIC OCEAN
BIOGEOCHEMISTRY
CHEMICAL COMPOSITION
CHEMISTRY
CONCENTRATION RATIO
DIAGENESIS
DISTRIBUTION
ELEMENTS
ENERGY
GEOCHEMISTRY
HYDROGEN COMPOUNDS
KINETICS
MERCURY
METALS
ORIGIN
OXYGEN COMPOUNDS
PACIFIC OCEAN
REACTION KINETICS
SEAS
SEAWATER
SEDIMENTS
SPATIAL DISTRIBUTION
SURFACE WATERS
VARIATIONS
WATER