Chemical composition of oceanic aerosol

The aerosols in maritime air were studied to assess the importance of wind transport of continental aerosols to the ocean. Aerosol samples were collected from ships in the Pacific Ocean. Each sample was chemically analyzed after being divided into two fractions, namely the water soluble fraction and the insoluble particulate fraction. Maritime aerosols are comprised mainly of sea salt. The concentration of sea salt increased about 10 times for each 4-m/sec increase of wind velocity. Cl/Na ratios of 3 to 6, higher than those of sea water, were observed in the samples collected by the bubbling of air in the midlatitudes of the North Pacific. The same enrichment was observed in the rainout fraction of the oceanic rain over Hachijo-jima Island, the excess chloride corresponding to 10% of the excess sulfate. Excess Ca was also observed; the water insoluble fraction of maritime aerosols did not appear to be the source of the Ca. High concentrations of red dust were measured in snow falling in Japan; this material was probably derived from the Eurasian continent. These observations suggest that large quantities of insoluble aerosols of continental origin are transported from arid land areas to the ocean by the discrete events of violent storms and that such events may contribute significant quantities of material to pelagic sediments.