Anoxic

Anoxic describes processes, which occur in the absence of molecular gaseous oxygen, but other forms of oxygen are still present (in opposite to anaerobic, which means that there is no oxygen at all) and used for the respiration of microorganism. Anoxic conditions are often found at the interface between aerobic and anaerobic environments (e.g. in trickling filters or in facultative ponds).The biological conversion of nitrate is to nitrogen gas is anoxic. This process is also known as denitrification.