The relationship between chromophoric dissolved organic matter and dissolved organic carbon in the European Atlantic coastal area and in the West Mediterranean Sea (Gulf of Lions)

The absorption coefficient of chromophoric dissolved organic matter (aCDOM) has been found to be correlated with fluorescence emission (excitation at 355 nm). In the coastal European Atlantic area and in the Western Mediterra nean Sea (Gulf of Lions), a significant statistical dependence has been fou nd between aCDOM and fluorescence with dissolved organic carbon (DOC) conce ntration. The relationship shows that, in the river plume areas (Rhine in t he North Sea and Rhone in the Gulf of Lions), a consistent fraction of DOC (from 40% to 60% of the average of the DOC measured) is non-absorbing in vi sible light range, where the dissolved organic matter (DOM) is typically ab sorbent. In comparison, in the open sea, apparently not affected by the con tinental inputs, the entire nOC belongs to the chromophoric DOM whose speci fic absorption is lower (5 to 10 times) than that found in the river plume areas. (C) 2000 Elsevier Science B.V. All rights reserved.