Ok that’s good to know! Being able to find a few crucial sound effects online that are under appropriate licenses that we could use will help a lot.
For demonstration, here’s a quick test track I threw together for a Vents Ambience track. It uses the “Underwater Snowstorm” track made by Yuri which works as a perfect Underwater Hum sound effect constantly playing in the background. Then I sprinkled in three underwater explosions off of Freesound.org to show when the vents release another burst of gas (they are pretty bad quality so you can hear the buzz of the microphone during their clips). Finally I added some bubbling taken from the current microbe_ambience2.ogg track. Sometimes an explosion leads to bubbling, sometimes it doesn’t, just to see what sounds best. Give a listen and provide your thoughts!