9301298 Wong Iodine can be found in seawater as IO3- and I- although I- is thermodynamically unstable relative to IO3. Although iodine is the most abundant biophilic minor element in the ocean and the distribution of IO3- and I- in the open oceans are relatively well known, direct evidence on the processes that may control its speciation is largely incomplete. Preliminary data from the South Atlantic Bight and East China Sea suggest that IO3- may be reduced to I- preferentially in the shelf-seas. Within the shelf, the reduction may be especially efficient in the inner shelf and the adjoining marshes and lagoons. Thus, during the exchanges between the marginal seas and the ocean interior, IO3- rich water may be added to the shelf while I- rich water may be exported to the ocean interior. This model will be tested with additional field observations to assess the relative importance of biological and non-biological processes in controlling the reduction of IO3-.
