  We experimentally investigate the effect of Reynolds number (Re) on the
turbulence induced by the motion of bubbles in a quiescent Newtonian fluid at
small Re. The energy spectra, $E(k)$, is determined from the decaying
turbulence behind the bubble swarm obtained using particle image velocimetry
(PIV). As the bubble Reynolds number decreases, the signature $k^{-3}$ of the
energy spectra for the bubble induced turbulence is replaced by a scaling
similar to the classical $k^{-5/3}$ Kolmogorov's scaling, where $k$ is the
wavenumber. We find that for Re $<$ $O$(100) the slope of the normalized energy
spectra is no longer independent on the gas volume fraction. This is further
corroborated using spatial correlation of the velocity vector behind the bubble
swarm. Thus, we provide experimental evidence to the claim by
\citet{mazzitelli2003effect} that at low Reynolds numbers the normalized energy
spectra of the bubble induced turbulence will no longer show the $k^{-3}$
scaling because of the absence of bubble wake and that the energy spectra will
depend on the number of bubbles, thus non-universal.
