Bubbles, Dissolved Oxygen saturation and coastal abrasion in the southern Baltic Sea

Breaking waves mediated generation of bubbles is extremely enhanced in the coastal waters. Waves are typically broke over the coastal ridges, forming parallel to the water line streaks of whitecaps. Since approximately half of the wave energy is dissipated to produce bubbles in the water, their abundant presence in a coastal waters indirectly contributes into protecting coastal zones against erosion. Experiments conducted during the warm seasons in the southern Baltic Sea waters indicated that the breaking wave mediated production of bubbles is substantially enhanced under the conditions of oxygen supersaturation. Since the degree of oxygen supersaturation increases with eutrophication of the coastal waters, the observed increased oxygen supersaturation in the southern Baltic Sea might be regarded as an additional factor that protects coastal areas during the warm seasons. However, the opposite effects are expected to be operative during the winter seasons, when oxidation of organic matter force the process of oxygen depletion.