Concentration of bacteria in jet drops from bursting bubbles
Blanchard, Duncan C.; Syzdek, Lawrence D.
Журнал:
Journal of Geophysical Research
Дата:
1972
Аннотация:
Serratia marcescens has been used to demonstrate that bacterial concentrations in jet drops from bursting bubbles can be much higher than the concentration in the water in which the bubbles burst. The ratio of the concentrations is the concentration factor C. A rotating tank was used to study the stripping of bacteria from the bulk air‐water interface. Values for C range from 1 to about 100, increasing with drop size up to about 80 μm in diameter. For a given drop size, C varies inversely with the bacterial concentration in the bulk suspension. A bubble ‘aging tube’ has been developed in which bubbles can be aged (while suspended in a downward moving stream of water) for any given time before they rise to the surface to break. Drops from these bubbles show an increase of C with bubble age, indicating a time rate of change of the adsorption of bacteria to the surface of the bubble. C reaches a steady‐state value as high as 10<sup>4</sup> in 10–20 sec. Surface‐active organic material is also adsorbed onto a rising bubble. This process lowers the surface‐free energy and, in turn, results in a decrease of the jet‐drop size and ejection height.
1.110Мб