This study investigates the oxidation and speciation properties of cobalt in water, a little understood metal.  Cobalt is required as a central element in vitamin B-12, essential for all life.  As such, it can be a limiting factor for phytoplankton.  Initial work focused on refining the analytical method, Competing Ligand Exchange-Adsorptive Stripping Voltammetry, a highly sensitive, accurate method with extremely low detection limits.  Field sampling from Linsley Pond, a freshwater system in Branford Connecticut has been done, followed by more refining of the analytical method before analyzing seawater.