The meridional distribution of dissolved iodine in near-surface waters of the Atlantic Ocean

Dissolved total iodine and iodate have been measured along an approximately north-east, south-west transect between the British Isles and Falkland Isles. Total iodine showed very little variation between the surface and 200 m. For the surface samples the coefficient of variation was 3.5%. Iodate concentrations varied between 0.30 and 0.45 mu M, with the lowest occuring at the equatorial surface. These results together with an earlier similar set for the Pacific ocean are used to argue that, in general, iodate reduction can be modelled separately from iodine uptake-regeneration. Correlation between iodate and nitrate concentrations was high (r(2)>0.93) in the permanently stratified waters of the sub-tropics and tropics. However, upwelling off Cape Verde shows that these correlations are the result of hydrographic coupling rather than direct chemical coupling of the two systems. (C) 2000 Elsevier Science Ltd. All rights reserved.