Brown Pocket in SandBed

Along the edged of my tank where the current has formed some sand dunes I can see about 3/4 of an inch below the surface sand there is brown / reddish pockets with trapped air. Should I stir the bed to move this around or leave it be?

is this an anaerobic pocket or just some trapped algae?

 

Maybe both. i would leave it alone.8)

 

It's cyanobacteria. The glass is taking light to it (kinda like fiber optics) and it's producing Oxygen (the bubbles).

 

I wouldn't stir it up it may release unwanted nitrites which can be harmful.

E

 

Thanks all, I'll keep an eye on it and try to do further research the way the pockets are formed it kind of has me held hostage to moving any of my rock around because between the current and the goby my sandbed is uneven.