Nitrogen Cycle Flashcards
Use to revise for the Nitrogen Cycle
What is Atmospheric Nitrogen Fixation? What Earth’s spheres are involved and how?
When lightning strikes separate nitrogen gas into nitric oxide and nitrogen dioxide and dissolves in water droplets, forming nitric acid, which gets transported to the Earth’s surface through precipitation?
Spheres involved:
Atmosphere - Nitrogen Gas
Hydrosphere - Nitrogen oxide/nitrogen dioxide dissolve in water droplets.
What is Assimilation? What Earth’s spheres are involved and how?
When ammonia/ammonium gets taken up from the soil by plants to make important biological molecules like DNA and proteins.
Spheres involved:
Atmosphere - Ammonia was once Nitrogen in the Air
Lithosphere - Ammonia comes from soil
Biosphere - Ammonia taken up by plants
Define the Nitrogen Cycle
The Nitrogen cycle addresses the many forms of nitrogen as it takes part in Earth’s 4 Spheres
What is Consumption? What Earth’s spheres are involved and how?
Animals acquire organic nitrogen by consuming plants or other animals.
Spheres involved:
Atmosphere - Nitrogen
Biosphere - Consumption of Animals and Plants
What is Ammonification? What Earth’s spheres are involved and how?
Decomposers decompose dead organisms and return their nitrogen back to the soil as ammonia.
Spheres involved:
Atmosphere - Nitrogen once in the air
Biosphere - Dead matter & decomposers
Lithosphere - Nitrogen goes into the soil as ammonia
What are Volcanic Eruptions? What Earth’s spheres are involved and how?
These eruptions release nitrogen gas straight into the Atmosphere. The heat and pressure transform the gas into nitrogen oxide, which reacts with water vapour to form precipitation.
Spheres involved:
Lithosphere - Volcanoes
Atmosphere - Release of nitrogen gas
Hydrosphere - Nitrogen oxide reacts with water vapour to form precipitation
What is Denitrification? What Earth’s spheres are involved and how?
Denitrifying bacteria convert nitrates (No-3) in the soil into nitrogen gas (N2) and release them into the air.
Spheres involved:
Atmosphere - Nitrogen gas released to the air
Lithosphere - Nitrates in the soil are converted into nitrogen gas
Biosphere - Denitrifying bacteria do the converting
What is Nitrogen Fixation by Bacteria? What Earth’s spheres are involved and how?
Nitrogen-fixing bacteria convert nitrogen gas (N2) into ammonia (NH3) or ammonium (H4N+) by breaking the bonds and adding hydrogen atoms to it, so that it can be used by organisms. They are placed in the soil.
Spheres used:
Atmosphere - Nitrogen gas is converted into Ammonia or Ammonium
Biosphere - Nitrogen-fixing bacteria do the converting to convert the nitrogen into a form usable by all organisms
Lithosphere - ammonia, ammonium and bacteria in soil
What is Nitrification? What Earth’s spheres are involved and how?
Nitrifying bacteria add oxygen to ammonia in the soil to form Nitrite (NO2-) to Nitrate (NO3-). Sometimes, plants prefer to assimilate nitrates and can make the same molecules.
Spheres involved:
Atmosphere - Ammonia was once nitrogen in the air before conversion
Biosphere - Bacteria and Plants
Lithosphere - Conversion happens in the soil
