VERTEX manganese transport with CaCO3

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Martin, J. H., & Knauer, G. A. (1983). VERTEX manganese transport with CaCO3. Deep Sea Research Part A, Oceanographic Research Papers, 30(4), 411-425.
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TitleVERTEX manganese transport with CaCO3
AuthorsH. Martin, A. Knauer
AbstractManganese transport was studied off central California in August and September 1981 as part of the VERTEX (Vertica l Transport and Exchange) research program. Refractory, leachable, and dissolved Mn fractions associated with particles caught in traps set at 11 depths (50 to 2000 m) were analyzed. Through intentional and unintentional CaCO3 dissolution 'experiments', it was learned that the weakly leachable Mn was originally in association with the carbonate phase. Adsorption on surfaces rather than absorption in CaCO3 matrices was indicated by the finding that Mn was not released in proportion to the CaCo3 dissolved, instead it appeared to keep readsorbing to the dissolving surface. Ultimately, Mn went into solution when the particulate CaCO3 was essentially depleted, suggesting that sufficient sites for adsorption were no longer available. Manganese fluxes with CaCO3 were low near the surface (0.1 mg cm-2 ky-1), but increased rapidly in the 50 to 200-m depth interval, and then became more or less constant (1.3 mg cm-2 ky-1 for the remainder of the water column (300 to 2000 m). Rate-of-change estimates indicate that Mn is rapidly scavenged in near-surface waters (-130 ng 1-1 y-1) and slowly regenerated at depth (2.7 ng 1-1 y-1) in our near-shore study area. Residence times for dissolved Mn were estimated at 1.2 y for surface waters and 17 y at depth. The implications of Mn transport with CaCO3 in relation to open-ocean sediment excess Mn are discussed. © 1983.
JournalDeep Sea Research Part A, Oceanographic Research Papers
Date1983
Volume30
Issue4
Start page411
End page425
ISSN01980149
NoteCited By (since 1996):15, Oceanography

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