COG3

Post-Doctoral Fellow, Boyle Lab, MIT.
Title: Concentrations and Chemical Speciation of Zinc and Cadmium : Exploring
sources, transport and more.

Abstract :
Zinc and Cadmium are essential for phytoplankton's carbon uptake
enzymatic mechanism. The bioavailable forms of these metals are
believed to be the free and inorganic species.

Using Anodic Stripping Voltammetry (ASV), the chemical speciation of
these two metals has been determined in complete water column stations
in the Western North Pacific and the Equatorial South Atlantic, as
well as in the water column and the benthic fluxes in the Elizabeth
River and the Chesapeake Bay. With a novel mathematical
interpretative tool, the speciation results show statistically robust
information about the ligands that complex these two metals.

The relationship between specific organic ligands and pigment
concentrations and ratios allow for some inferences about specific
phytoplankton species in some oceanic regions. On the other hand,
recent literature suggests new directions for interpreting the
ligands' sources and transport mechanisms. The depth profiles
obtained in these oceanic regions suggests that marginal seas and
other pointed sources provide strong organic complexing ligands and
metals, apparently combining riverine, terrestrial, marine and
anthropogenic matter. The ligands are shown to be transported along
water masses, some decaying with time. A consortium of ligands
complexes these two metals, affecting the chemical speciation of
shallow, intermediate and deep waters. Finally, the potential
ramifications of this are discussed, with emphasis on the close and
remote upwelling of potentially limiting concentrations of
bioavailable Zinc and Cadmium, along with inferred Cobalt.