Fig. 1.
a) Schematic drawing of experimental setup. The circle represents the glass flask, and the square the temperature-controlled bath. Arrows indicate direction of airflows. b) Five-necked glass flask in which bubble generation and bursting took place.
Table 1.
Overview of experiments performed and key results: number of particles produced per bubble (Nbubble, av.) at 0 °C and 19 °C respectively and the difference (#/bubble).
[i] AC: after cooling. Uncertainties represent one standard deviation. *Cf. Sup. Inf. The date of the performance of the experiments with respect to the near-shore water is the same as the date of the collection of the sample. Salinity data for near-shore seawater comes from DMI (the Danish Institute of Meteorology)(DMI, 2017), site accessed 11/15/24 of May 2017. Salinity data for non-near-shore water was measured with a SBE 4 conductivity sensor on the Seabird CTD 911 sampling device. **The measurement of salinity of the non-near-shore water started at 1 m depth, and the values given are therefore given under the assumption that the salinity at 1 m depth is similar to the salinity at the surface.
Fig. 2.
Measured particle concentration (black), solution temperature (blue) and air temperature (red) in the flask headspace during bubbling experiments in: a) NaCl solution, 35 g/l, b) Sigma Sea Salt solution, 35 g/l. Notice the different scales on the y-axes showing particle concentrations.
Fig. 3.
Measured particle concentration (black), saline solution temperature (blue) and air temperature (red). a) Seawater sample, filtered with active charcoal, (non-near-shore) collected at 8 m depth in the bay of Aarhus (cf. section 2.3. b), Homemade sea salt, 35 g/l.
Fig. 4.
Near-shore seawater from Ballehage. Measured particle concentration (black), saline solution temperature (blue) and air temperature (red).
Fig. 5.
Overview of experimental results. The figure illustrates the very large (orders of magnitude) change in particle production per bubble with temperature for bubbles bursting in real seawater and NaCl solutions. The figure also demonstrates the influence of a model surfactant (succinic acid) and divalent cat-ions on the temperature-dependent particle production.