The Nitrogen Cycle (including human influences)

The Nitrogen Cycle (including human influences)

The Nitrogen Cycle

  • The Nitrogen cycle illustrates how nitrogen (N), an essential nutrient for life, is converted into various forms within the environment.
  • Nitrogen is found in several states in the environment and the changes it undergoes form a major part of the nitrogen cycle.
  • Nitrogen gas (N2) makes up about 78% of the Earth’s atmosphere.

Key Steps of the Nitrogen Cycle

  1. Nitrogen Fixation: Process where N2 is converted into a usable form (like ammonia NH3) by nitrogen-fixing bacteria or through lightning strikes.
  2. Ammonification: A process where decaying organisms and waste products are converted into ammonia by bacteria and fungi.
  3. Nitrification: In this two-step process, ammonia is first converted into nitrite (NO2-) by bacteria called Nitrosomonas. Then, another type of bacteria called Nitrobacter converts nitrite into nitrate (NO3-).
  4. Assimilation: Plants absorb nitrates from soils into their roots and convert them into proteins. Animals then consume these proteins by feeding on the plants.
  5. Denitrification: The process where nitrates in the soil are broken down by bacteria and released back into the atmosphere as nitrogen gas (N2), completing the nitrogen cycle.

Human Influences on the Nitrogen Cycle

  • Synthetic Fertilizers: Overuse of nitrogenous fertilizers can lead to high concentrations of harmful nitrates in groundwater.
  • Burning of Fossil Fuels: This releases various nitrogen oxides into the air, creating smog and contributing to acid rain.
  • Haber Process: This is a method used to produce ammonia from nitrogen, thus artificially enhancing nitrogen fixation and disrupting the natural balance.
  • Deforestation and Soil Erosion: These practices disrupt the nitrogen cycle by removing plants that help convert nitrogen into usable forms, and by washing away nitrate-rich soil.

By understanding the processes behind the nitrogen cycle and acknowledging the potential human influences, it is possible to take conscious steps towards better environmental practices and planetary health.