THE DISTRIBUTION OF DISSOLVED IODINE IN HEBRIDEAN WATERS DURING MIDWINTER

The distribution of dissolved total iodine and iodate in the waters of f the Scottish coast around the Outer Hebrides in late January 1977 is described. Three types of water are delineated by the iodine results, open ocean proper, outer continental-shelf water, and coastal current water. The results confirm the sluggishness of iodide oxidation in se awater. The region between the ocean proper and the western edge of th e coastal current is characterised by intel conversion of iodate and i odide with little concomitant loss of total iodine. This behaviour is attributed to biological effects during the previous summer and autumn , and is seen as a general phenomenon extending along the continental margin. Implications are discussed of the finding that some of the Sco ttish coastal currents contained much lower concentrations of total io dine and iodate concentrations than those observed in the Irish Sea du ring the previous autumn.