C18 Sep-Pak extractable dissolved organic copper related to hydrochemistryin the North-West Mediterranean

Extractable organic copper using C18 Sep-Pak cartridges was investigated in seawater after laboratory experiment showed that the (C18 Sep-Pak) cartrid ges were reliable, in open and coastal waters with normal levels of dissolv ed organic carbon, for the separation of a specific fraction of organo-copp er complexes. Given that the Sep-Pak cartridges retain the hydrophobic fraction of the di ssolved organic matter, this extraction technique was applied for studying the characteristics of this particular hydrophobic dissolved organic copper fraction (hDOCu) in the north-western Mediterranean waters. Surface distri bution of hDOC is influenced by organic matter input from the river Rhone a nd its estuary as well as the physical processes affecting the primary prod uctivity such as coastal upwelling. By correlating hDOCu concentrations wit h total dissolved copper and other hydrochemical data such as salinity and dissolved organic carbon, it was possible to examine the behaviour of hDOCu in the water masses of different sources and ages. Marine organic matter has been shown to have high complexing capacity. Prod uctive superficial and intermediate waters as well as deep waters showed re latively high and comparable complexing capacity indicating that old organi c matter may have strong complexing sites. (C) 2000 Academic Press.