Mercury in the Atlantic Ocean: factors controlling air-sea exchange of mercury and its distribution in the upper waters

To understand further the cycling of mercury at the earth's surface we disc uss the results of recent measurements of Hg concentration and speciation i n the upper ocean and marine boundary layer of the Atlantic Ocean. In water , dissolved gaseous Hg (DGHg) and total Hg measurements are reported; for t he atmosphere, total gaseous Hg, reactive gaseous Hg (RGHg) and particulate Hg measurements were made. These measurements allow estimation of gas evas ion to the atmosphere and deposition to the ocean. In conjunction with the field collections, incubation experiments both on board ship and in the lab oratory have examined further the processes controlling the oxidation and r eduction of Hg species in water. Our results suggest that dry deposition of RGHg could be significant. (C) 2001 Elsevier Science Ltd. All rights reser ved.