The operation of an airlift pump, working under low submergence ratios (between 0.17 and 0.31), has been visually studied. The two-phase flow structures occurring in the riser channel and around the injector section were recorded by a high speed video system. A quasi-periodic burst-like behaviour characterised the now pattern in the riser tube, which appeared to dominate the operation of the airlift pump under the conditions of low submergence ratios. An interesting aspect of die airlift pump operation, under these conditions, is that the two phases show a large interface area; this is due to th : high dispersion degree of the two-phase mixture in the riser duct. Data and pictures from video recordings regarding the sequence, time and length scales of the occurring flow patterns are reported.