The solution speciation and solid-phase suspended particulate fractionation of the trace metals Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb were investigated in the Black Sea, the world's largest anoxic basin. Sequential filtration/ion-exchange and selective leaching techniques were developed for the determination of dissolved and solid-phase trace metal fractionation. Field measurements were compared with the results of a thermodynamic equilibrium model. The transition metals (Mn, Fe, and Co) were controlled by changes in redox state across the oxic/suboxic/anoxic boundary and by metal-sulfide precipitation in the anoxic deep waters. Dissolved transition metal concentrations were low in the surface waters, increased to maxima in the upper anoxic zone, then decreased again into the deep waters. Dissolved Mn and Fe approached saturation with respect to MnS$\sb2$ (haurite) and to FeS (mackinawite) or Fe$\sb3$S$\sb4$ (greigite) in the deep waters. Dissolved Co was best explained in terms of a scavenging/regeneration cycle with Mn-oxyhydroxides across the sulfide interface and coprecipitation of Co with Fe-sulfides in the deep waters. Dissolved Ni was nearly constant with depth. / The Class B metals (Cu, Zn, Cd, and Pb) were high in the surface waters and decreased rapidly across the sulfide interface, consistent with metal-sulfide precipitation below the interface. The dissolved metal fractionation was dominated in the oxic zone by "free" metal species, shifting to dissolved metal-sulfide complexes below the interface. / With the exceptions of Al and Fe, the suspended matter trace metal fractionation was dominated by weak-acid soluble forms. Strong-acid leachable forms, probably metal-sulfide phases, were important in the deep waters for Mn, Fe, and Co. / Source: Dissertation Abstracts International, Volume: 52-02, Section: B, page: 0705. / Major Professor: William M. Landing. / Thesis (Ph.D.)--The Florida State University, 1990.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78432 |
| Contributors | Lewis, Brent Layne., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 395 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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