Anoxic refers a region having no oxygen present, with nitrite and nitrate present and taking over the function as the oxidiser (with the oxidation reduction potential between +50 and -50 mV).
Within a reef system, denitrification (conversion of nitrate to nitrogen gas) occurs in the anoxic regions (includes interior regions of liverock, bottom layers of sand bed and inside a denitrator i.e. surfaces not directly in contact with the water).
The presence of oxygen is referred to as aerobic and the absence anaerobic.
Oxygen will penetrate through approximately 0.5 millimeters of a stationary biofilm.
- ↑ (http://dx.doi.org/10.1016/j.bej.2003.10.003): Hibiya, K., Nagai, J., Tsuneda, S., and Hirata, A., Simple prediction of oxygen penetration depth in biofilms for wastewater treatment, Biochemical Engineering Journal, 19(1), (2004), 61-68.