On the flotation of particulates in sea water by rising bubbles

A simple batch-type foam separation apparatus was used to determine the degree to which rising bubbles could scavenge and enrich the surface layers of a column of sea water with particulate matter. By comparing the amount of particulates in the original material with that later-recovered material in the enriched surface layers of the column, per cent recoveries were obtained for various samples of natural and laboratory origin. Recovery of particulates in natural samples was consistently high, whereas recovery of particulates from unicellular algal cultures varied, the apparent parameter governing the degree of recovery being the age of the culture in question. The potential significance of this phenomenon as it affects material transport across the air-sea interface will be discussed.