Newly recognized vital nitrogen cycle.
D000388:Air; D000397:Air Pollution; D000401:Aircraft; D001419:Bacteria / Q000378:metabolism; D005118:Extraterrestrial Environment; D009569:Nitric Oxide; D009586:Nitrogen Fixation; D009609:Nitrous Oxide / Q000096:biosynthesis; D010126:Ozone; D010777:Photochemistry; D011549:Pseudomonas / Q000378:metabolism; D012988:Soil Microbiology; D014466:Ultraviolet Rays
D009569:Nitric Oxide; D010126:Ozone; D009609:Nitrous Oxide