Microaerophilic organisms are a specific type of microorganism (especially bacteria) that requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in the atmosphere (~20% concentration). Many microphiles are also capnophiles, as they require an elevate concentration of carbon dioxide. (In the laboratory they can be easily cultivated in a candle jar, a container into which a lit candle is introduced before sealing the airtight lid. The flame burns until extinguished by oxygen deprivation, creating a carbon dioxide-rich, oxygen-poor atmosphere.)