engleski

Copper complexation and surfactant activity of organic matter in coastal seawater and surface microlayer samples of north Norwegian fjords and Mediterranean

Organic ligands capable of complexing copper ions (CCu) were measured in selected sea surface microlayer (ML) and underlying water (UW) samples from the NW Mediterranean coastal waters and of the north Norwegian fjords. A part of these organic ligands , exhibit the property of surface activity, i.e. they accumulate on different phase boundaries (air/water ; water/sediments ; water/ biological membranes) and are determined as surface active substances (SAS). The presence of Cu complexes with surface active properties influences the biogeochemical cycle of copper ions at these phase boundaries. The CCu values for all samples determined by differential pulse anodic stripping voltammetry (DPASV) are in the range 90 to 1790 nM (being in general higher for microlayer samples). The SAS values for the samples are in the range 0.062 to 0.216 mg/ L eq.T-X-100 while dissolved organic carbon (DOC) values are in the range from 0.9 mg/L C to 3.7 mg/L C. CCu data for North Norwegian fjords (ML and UW samples) are well correlated with DOC data. CCu data are correlated with SAS data for North Norwegian fjords (ML and UW), while in NW Mediterranean CCu data are correlated with SAS only in UW samples. In the marine environments investigated 1-20 % of DOC is present as ligands capable to complex copper ions. Correlation of SAS vs. DOC data for all the samples has shown that majority of field data are in properties similar to model fulvic acid and microbial polysaccharide xanthan.

dissolved organic ligands; surface active substances; copper; sea surface microlayer; complexing capacity; voltammetry

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