Dry ice sublimation rate in water

As I got some a finger sized of dry ice in water, it started to bubble vigorously as expected and gave off a lot of smoke. But after 3 minutes or so, the rate of sublimation seems to slow down a lot, and in only bubbles from one spot of the ice, and the rest of the dry ice seems to be not sublimating anymore. I dropped the dry ice into tap water.


So what causes the decrease in rate of the sublimation? Would drinking/distilled water cause different results from tap water?


Thanks!


