Low level electrostatic ion acoustic turbulence generated by the ion-ion beam instability was investigated numerically. The fluctuations in potential were investigated by a conditional statistical analysis revealing propagating coherent structures having the form of negative potential wells which correspond to ion phase space vortices. The results demonstrate the importance of clump formation in ion phase space for the dynamics of the turbulence. The statistical analysis gives results in terms of averages over a conditionally selected subensemble. Because of the intermittent character of the turbulence it proved possible to devise a method, which permits recognition of essentially all coherent structures. With most of the structures recovered we are able to estimate their distributions of amplitude, width and velocity. A statistical evidence for interaction, i.e., binding, of phase space vortices was obtained.