Micro Bubbles???

Hey guys, all of a sudden i have noticed micro bubbles forming on some of my rock and rising to the surface.
They seem to be coming from within them.

I have a few thought as to what it may be but would like to see what you guys would conclude it is.

1. I have recently installed a skimmer and dissolved oxygen is reforming?

2. Air that was still in the rock is being displaced as water seeps in deeper (since some of it has only been put in a few weeks ago)?

3. Bacteria is creating nitrogen gass?

Hey Mike,it shouldn’t be nitrogen, that function is on an atom level making them very small and more or less, water soluble.
There are some possibilities, air trapped and coming out, hydrogen sulphide being expelled from changes of conditions or a current directing bubbles under the rock and up they go, but larger as they combine.
If it was from the out side and they were new and hard to see them as yet, it would be algae including diatoms or cyano bacteria making the oxygen bubbles.
I wouldn’t worry mate unless a water pump in the aquarium is chopping them up and making the issue larger by harming inverts.

the algae would make sense as the only rocks it seems to be coming off are the ones that have algae on them due to the lighting conditions and how long they been in there. cheers