Organic Complexation of Metals in Sea Water
Metals dissolve in water by ionisation, and their solubility is usually restricted by their solubility product with one of the major anions in sea water, such as with hydroxide, carbonate or phosphate. Their solubility is increased by the formation of soluble complexes with the major anions. The concentrations of the vast majority of the metals in the oceans are usually much less than their solubility because they are scavenged from solution by interaction with settling particles, including microorganisms, faecal pellets and inorganic hydroxides or oxides of poorly soluble metals. This interaction, and therefore the residence time of the elements, could be modelled using chemical equilibria if we knew the chemical speciation of the metals, and the interaction of the various species with the particles including their availability for uptake by the microorganisms. For some metals it is now known that their chemical speciation is dominated by organic complexation. This aspect will be discussed in detail in this chapter.
KeywordsWater Column Organic Complexation Ligand Concentration Total Metal Concentration Conditional Stability Constant
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