Interfacial phenomena frequently give rise to energetic fluid motions in the culture of plant and animals cells, and these motions may result in loss of cellular viability. Bubble disengagement processes have often been the center of attention in this regard Recent work has shown, however, that surprisingly large interfacial velocities can be generated in aqueous solutions of glycerol by an elongation-retraction mechanism occurring just above the orifice following bubble formation at sieve-plate spargers. White it is evident that this process can occur under a variety of conditions, it is now clear that certain combinations of hole size, gas rate, and medium viscosity result in unusually energetic interfacial motions. An extensive investigation of this phenomenon has been completed, involving both the collection of experimental data and hydrodynamic modeling; this work has shown that shear stresses can be generated by this process that may be as large as 2000 to 3000 dynes/cm(2) in 50% glycerol solutions.