  We study the problem of sinking particles in a realistic oceanic flow, with
major energetic structures in the mesoscale, focussing in the range of particle
sizes and densities appropriate for marine biogenic particles. Our aim is to
unify the theoretical investigations with its applications in the oceanographic
context and considering a mesoscale simulation of the oceanic velocity field.
By using the equation of motion of small particles in a fluid flow, we assess
the influence of physical processes such as the Coriolis force and the inertia
of the particles, and we conclude that they represent negligible corrections to
the most important terms, which are passive motion with the velocity of the
flow, and a constant added vertical velocity due to gravity. Even if within
this approximation three-dimensional clustering of particles can not occur,
two-dimensional cuts or projections of the evolving three-dimensional density
can display inhomogeneities similar to the ones observed in sinking ocean
particles.
