Bubble populations and spectra in coastal waters: A photographic approach

A photographic analysis of bubbles generated in coastal seas by breaking waves and general turbulence has allowed the number and spectrum of sizes of bubbles greater than 17 ..mu..m in radius to be counted and observed. A distribution of numbers and sizes is presented for bubbles at 1.5-m depth arising from wave activity driven by winds of from 8 to 10 m s/sup -1/; under these conditions the number of bubbles was 2.7 x 10/sup 4/ m/sup -3/. In winds of 11--13 m s/sup -1/ the numbers of bubbles determined from photographs were 4.8 x 10/sup 5/ m/sup -3/ at 0.7-m depth, 1.6 x 10/sup 5/ m/sup -3/ at 1.8-m depth, and 1.6 x 10/sup 4/ m/sup -3/ at 4-m depth. The data acquired by this technique enable us and others to calculate the rate of the invasion of atmospheric gas into and out of the sea and to investigate the production of nonliving organic particulate matter by the processes of adsorption and bubble dissolution. The numbers of bubbles that do not dissolve completely but rise to the sea surface and burst are also calculable and are fundamental to quantifying the production of marine aerosols. A comparison of this techniquemore » with classical acoustic methods is now imperative.« less