Just to be the devils advocate, not all so called "Bubble Alage" is bubble algae, as in
Valonia sp, when it is in the "freee-living-sphere"form. Many may be just
Ventricaaria sp, which also release "spores". Then there some of the
Derbesia sp, which are in the "Halicystis Stage", which appear as dark green spheres. This is an alternative life sytle, which is completly different from the "turf" stage. The thing on the Derbesia is that it is always grows on crustose coralline alage and it floats when broken off, rather than sinks like the others