This type of data allows one to estimate the sources, transport, and sinks of the element within the environment. From these results we can identify some of the major processes that influence the element in the marine environment. One of the basic principles of chemistry is that the behavior of an element is determined by its molecular form. The element sulfur, for example, take on greatly different properties and chemical reactivity depending on its molecular form including its oxidation state, its chemical bonds to other elements such as oxygen or hydrogen, or its incorporation into organic matter through biological activity. We have used a combination of analytical and physical chemical techniques to understand what chemical species of specific elements are common in the marine environment.
Copper provides one example of such an investigation.
The chemical reactivity of copper, and its biological availability, depends on its chemical form. One approach to studying chemical speciation in seawater is to determine thermodynamic properties, such as the free energy, of particular species. This provides an equilibrium model for a constituent that allows predictions of its chemical behavior in response to various marine environmental variables such as temperature, pressure, salinity, pH, oxidation potential, and concentrations of organic complexing substances. We often find that due to biological and geochemical processes in the ocean, chemical equilibrium is not attained. Therefore, the kinetic properties of chemical species must also be known for a more complete and reliable chemical model of its behavior in the environment.