The world ocean is a major source of volatile organo-halogens to the atmosphere.These compounds,naturally produced by micro- and macroalgae,contribute to the destruction of stratospheric ozone and are involved in the formation of marine aerosols.The vertical and horizontal distribution of organo-halogens in the oceans give an indication of their origin,their degradation rate and their ease of evaporation,parameters needed to estimate the flux to the atmosphere.By high-resolution sampling from Alaska to Svalbard over the north pole during the 2005 Swedish-American Arctic expedition and by comparing to parameters,such as salinity and temperature,traditionally used to determine and define different water masses,the fate of naturally produced halocarbons can be elucidated.Depth profiles collected in the Canadian Basin,the Makarov Basin and the Amundsen basin and across the ridges will be presented.Of special interest is the distribution of organo-halogens just above the sea floor,from vertically closely spaced samples,which shows significant variation of concentration of these compounds in deep water,indicating sediment sources or processes.