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 Isl es. Total iodine showed very little variation between the surface and 200 m . For the surface samples the coefficient of variation was 3.5%. Iodate con centrations 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 bet ween iodate and nitrate concentrations was high (r(2)>0.93) in the permanen tly stratified waters of the sub-tropics and tropics. However, upwelling of f Cape Verde shows that these correlations are the result of hydrographic c oupling rather than direct chemical coupling of the two systems. (C) 2000 E lsevier Science Ltd. All rights reserved.