  The diffusion-driven growth of a dense cloud of bubbles immersed in a
gas-supersaturated liquid is a problem that finds applications in several
modern technologies such as solvent-exchange micro-reactors, nanotechnology or
the manufacturing of foamy materials. However, under Earth's gravity
conditions, these dynamics can only be observed for a very limited time if the
cloud is not attached to a surface, due to the action of buoyancy, i.e. of
gravity effects. Here, we present experimental observations of the time
evolution of dense bubble clouds growing in CO$_2$-supersaturated water in
microgravity conditions. We report the existence of three regimes where the
bubble cloud exhibits different growth rates. At short times, each bubble grows
independently following the Epstein--Plesset equation. Later on, bubbles start
to interact with each other and their growth rate diminishes as they compete
for the available CO$_2$. When this happens, the growth rate slows down. This
occurs earlier the deeper the bubble is in the cloud. Finally, at long times,
only those bubbles on the husk continue growing. These regimes may be
qualitatively described by a mathematical model where each individual bubble
grows in the presence of a constellation of point mass sinks. Despite the model
being only valid for dilute bubble clouds, its predictions are consistent with
the experimental observations, even though the bubble clouds we observe are
rather dense.
