Looks like bryopsis being overtaken by calothrix which is a light slimy yet hairy/fuzzy nastiness that loosely attaches to your rock work. Air bubbles are usually trapped while escaping the "algae", just like in your picture. Calothrix is a type of blue green algae that looks very similar to Dinos. Remove the rock and scrub, and then fine tune with a toothbrush. Let some cleaners get the rest. recommended cleaners are :
Chitons
Nerite snails
astrea snails
cerith snails trochus snails
6-8 caribbean blue leg hermits ( these are tiny)