  Geophysical fluid flows are predominantly turbulent and often strongly
affected by the Earth's rotation, as well as by stable density stratification.
Using direct numerical simulations of forced Boussinesq equations, we study the
influence of these effects on the motion of fluid particles, focusing on cases
where the frequencies associated with rotation and stratification (RaS), $N$
and $f$ respectively, are held at a fixed ratio $N/f=5$. As the intensity of
RaS increases, a sharp transition is observed between a regime dominated by
eddies to a regime dominated by waves, which can also be seemingly described by
simply comparing the time scale $1/N$ and $\tau_\eta$ (the Kolmogorov time
scale). We perform a detailed study of Lagrangian statistics of acceleration,
velocity and related quantities in the two regimes. The flow anisotropy induces
a clear difference between particle motion in the horizontal and vertical
directions. In the regime $N\tau_\eta <1$, acceleration statistics in both
horizontal and vertical directions, exhibit well known characteristics of
isotropic turbulence. In contrast for $N\tau_\eta >1$, they are directly
influenced by imposed RaS. The Lagrangian velocity statistics exhibit visible
anisotropy for all runs; nevertheless the degree of anisotropy becomes very
strong in the regime $N\tau_\eta >1$. We find that in the regime $N\tau_\eta
<1$, rotation enhances the mean displacement of particles in horizontal planes
at short times, but inhibits them at longer times. This inhibition of
horizontal displacement becomes stronger for $N\tau_\eta >1$, with no clear
diffusive behavior. Displacements in the vertical direction are always
inhibited. The inhibition becomes extremely strong when $N\tau_\eta >1$, with
the particles almost being trapped horizontally.
