  We study the influence of the turbulent transport on ice chemistry in
protoplanetary disks, focusing on carbon and nitrogen bearing molecules.
Chemical rate equations are solved with the diffusion term, mimicking the
turbulent mixing in the vertical direction. Turbulence can bring ice-coated
dust grains from the midplane to the warm irradiated disk surface, and the ice
mantles are reprocessed by photoreactions, thermal desorption, and surface
reactions. The upward transport decreases the abundance of methanol and ammonia
ices at r < 30 AU, because warm dust temperature prohibits their reformation on
grain surfaces. This reprocessing could explain the smaller abundances of
carbon and nitrogen bearing molecules in cometary coma than those in low-mass
protostellar envelopes. We also show the effect of mixing on the synthesis of
complex organic molecules (COMs) are two ways: (1) transport of ices from the
midplane to the disk surface and (2) transport of atomic hydrogen from the
surface to the midplane. The former enhances the COMs formation in the disk
surface, while the latter suppresses it in the midplane. Then, when mixing is
strong, COMs are predominantly formed in the disk surface, while their parent
molecules are (re)formed in the midplane. This cycle expands the COMs
distribution both vertically and radially outward compared with that in the
non-turbulent model. We derive the timescale of the sink mechanism by which CO
and N2 are converted to less volatile molecules to be depleted from the gas
phase, and find that the vertical mixing suppresses this mechanism in the inner
disks.
