  This study focuses on heat and mass exchange processes in hydrate foam during
its formation from methane bubbles in gas hydrate stability zone (GHSZ) of the
Lake Baikal and following delivery of it in open container to the lake surface.
The foam was formed as a result of methane bubble collection with a
trap/container. The trap was inverted glass beaker of diameter of 70 mm and 360
mm long. Open bottom end of the beaker used as enter for bubbles ascended from
the lakebed. At a depth of 1400 m all bubbles which fed to the trap were
transformed here into solid hydrate foam. The sensitive thermometer was mounted
in the middle of the trap and recorded the temperature inside trap. The fate of
the bubbles in the trap was recorded by video-camera. During ascend within GHSZ
with velocity of about 0.375 m/s we observed the continuous decrease of the
temperature in the foam up to a level of negative magnitude in a depth interval
of 1400 - 750 meters. Above 750 m temperature decrease was changed by small
growth. However once the trap ascended above top boundary of GHSZ at a depth of
380 m, the temperature fell sharply. Falling to a negative values -0.25 oC, the
temperature sharply stabilized and did not changed further until the trap
reached the surface. The decreasing of the temperature during the ascent is due
to the cooling of gas as a result of the performing of the work against the
forces of hydrostatic pressure. The temperature drop at the boundary of the
GHSZ is due to the absorption of heat by the decomposition of hydrate.
