science

Nitrogen Cycle

Nitrogen was discovered by Rutherford in 1772, but it had been known since the Middle Ages to the alchemists, who referred to it as "agua fortis", famously corrosive, and also as "aqua regia" with which they dissolved gold.

Some three decades after it was discovered that living plants needed nitrogen, Jules Reiset recognized in 1856 that decomposing organic matter releases nitrogen. This discovery eventually laid the foundation for the nitrogen cycle, as it was the first evidence of the nitrogen cycle in the biological realm.

Animals obtain their nitrogen (and all other compounds) from plants (or from animals that have fed on them). Four processes are involved in the nitrogen cycle through the biosphere: (1) nitrogen fixation, (2) decomposition, (3) nitrification, and (4) denitrification. Microorganisms play an important role in these four processes.