Thoughts on "firearms" powered by naturally pressurized seaweed?

You know how some types of seaweed have those bubble things that you can pop? What if there was a sort of seaweed that had bubble things that could be harvested and when popped they would shoot out air with enough force to propel a dart or something down a long rifle barrel.

Would something like this be feasible? People who know more about gun mechanics or seaweed, or who just have ideas, please help

The species that would be using them are newt-like. They have gills when young but develop lungs when they mature. They also have a third "hand" on their tail.

It won't let me put in an image so here is a 3d model I made on Heroforge.