  We investigate numerically the dynamics and statistics of inertial particles
transported by stratified turbulence, in the case of particle density
intermediate in the average density profile of the fluid. In these conditions,
particles tend to form a thin layer around the corresponding fluid isopycnal.
The thickness of the resulting layer is determined by a balance between
buoyancy (which attracts the particle to the isopycnal) and inertia (which
prevents them from following it exactly). By means of extensive numerical
simulations, we explore the parameter space of the system and we find that in a
range of parameters particles form fractal cluster within the layer.
