Определение nitrogen cycle в Английский Язык Английский Язык словарь
The natural circulation of nitrogen, in which atmospheric nitrogen is converted to nitrogen oxides by lightning and deposited in the soil by rain where it is assimilated by plants and either eaten by animals (and returned as faeces) or decomposed back to elemental nitrogen by bacteria
the circulation of nitrogen; nitrates from the soil are absorbed by plants which are eaten by animals that die and decay returning the nitrogen back to the soil
Circulation of nitrogen in various forms throughout nature. Nitrogen is essential to life, but in the atmosphere it is in a form (the diatomic molecule N2) unavailable to most organisms. Nitrogen fixation by microbes turns this nitrogen into nitrates and other compounds, which plants or algae assimilate into their tissues. Animals that eat plants in turn incorporate the compounds into their own tissues. Microbes decompose the remains and waste of all living things into ammonia (ammonification); the ammonia may leave the soil through vaporization into the air or leaching into water. Ammonia remaining in soil may be transformed by bacteria into nitrates (nitrification), which then can be reassimilated into living organisms, or into free nitrogen (denitrification), which reenters the atmosphere. Hence, once fixed from air, some nitrogen goes through the cycle repeatedly without returning to the gaseous state
A group of nuclear reactions, that involve the interaction of protons with carbon, nitrogen and oxygen nuclei, thought to be the main source of energy in main-sequence stars of greater than 1.4 solar mass