Bubbles Rising Out Of Sand Bed

[tmhasara]

I opened up the blinds to give my newly established tank some sunlight for the first time, and it's causing bubbles to form on the sand bed. There are clearly bubbles underneath the sand bed as well. I've read this is a natural part of the nitrogen cycle, but why does sunlight effect it, and are the effects good or bad?

[FishStrings]

My guess from the diagrams, there is a small layer of algae slime about an inch deep in the sand. Plants breathe oxygen at night and carbon dioxide when you turn on the lights. Since algae is a plant this maybe somehow effects gas exchanges right off the bat between the plant and bacteria layer in the sand. This is nothing but a scientific guess.