The Isolation and Partial Chemical Characterization of Bubble Transportable Organic Matter in Seawater

Abstract

A new sampling device has been developed that concentrates and collects from seawater large quantities of organic materials which are important in physico-chemical processes at the air-sea interface. This sampling scheme has been designed to emulate the naturally occurring oceanic process of bubble scavenging and breaking which leads to the formation of atmospheric aerosols enriched in organic carbon and various trace elements. The continuous flow bubble adsorption column has been used to collect aerosol samples from the North Atlantic Ocean during cruise 78-016 of the CSS Hudson in June of 1978. In addition, a twelve month sampling program was carried out in order to investigate seasonal changes in the composition of aerosols collected from seawater pumped from the Northwest Arm of Halifax Harbour. The concentration of organic carbon in the aerosol samples was found to be enriched relative to the original seawater samples by factors of 47 to 572 . The nature of the collected material has been investigated using various chemical techniques including stable carbon isotope analysis, separation chemical class on Sephadex reactions and molecular size gels. The chemical composition of the coastal samples was found to vary with the seasons and the aerosols generally contained a higher proportion of low molecular weight compounds than those generated from oceanic water samples. The influence of the Northeast Atlantic current can be discerned in the composition of the aerosols from t he North Atlantic surface waters.