  We search for frozen water and its processing around young stellar objects
(YSOs of class I/II). We try to detect potential, regional differences in water
ice evolution within YSOs, which is relevant to understanding the chemical
structure of the progenitors of protoplanetary systems and the evolution of
solid materials. Water plays an important role as a reaction bed for rich
chemistry and is an indispensable requirement for life as known on Earth. We
present our analysis of NAOS-CONICA/VLT spectroscopy of water ice at 3um for
the TTauri star YLW 16A in the rho-Ophiuchi molecular cloud. We obtained
spectra for different regions of the circumstellar environment. The observed
absorption profiles are deconvolved with the mass extinction profiles of
amorphous and crystallized ice measured in laboratory. We take into account
both absorption and scattering by ice grains. Water ice in YLW 16A is detected
with optical depths of between tau=1.8 and tau=2.5. The profiles that are
measured can be fitted predominantly by the extinction profiles of small grains
(0.1um - 0.3um) with a small contribution from large grains (<10%). However, an
unambiguous trace of grain growth cannot be found. We detected crystallized
water ice spectra that have their origin in different regions of the
circumstellar environment of the TTauri star YLW 16A. The crystallinity
increases in the upper layers of the circumstellar disk, while only amorphous
grains exist in the bipolar envelope. As in studies of silicate grains in
TTauri objects, the higher crystallinity in the upper layers of the outer disk
regions implies that water ice crystallizes and remains crystallized close to
the disk atmosphere where water ice is shielded against hard irradiation.
