Which of the following processes mainly contributes to the reduction of oxygen levels in the atmosphere in the oxygen cycle?

Key Points

• Respiration is the process by which living organisms take in oxygen and release carbon dioxide. This process reduces the levels of oxygen in the atmosphere.
• Combustion is a chemical process in which a substance reacts rapidly with oxygen and gives off heat. This process consumes oxygen and releases carbon dioxide, thus reducing oxygen levels.
• Formation of nitrogen oxides occurs during high-temperature combustion processes. These oxides can react with oxygen and contribute to the depletion of atmospheric oxygen.
• These processes collectively contribute to the reduction of oxygen levels in the atmosphere as part of the oxygen cycle.

Additional Information

• Respiration:
  • Respiration is the process of breaking down glucose to produce energy, which involves taking in oxygen and releasing carbon dioxide.
  • It occurs in all aerobic organisms including humans, animals, and plants during the night.
• Combustion:
  • Combustion is a chemical reaction that typically occurs when a fuel reacts with an oxidant, releasing heat and light.
  • Common examples include the burning of fossil fuels such as coal, natural gas, and gasoline.
• Nitrogen Oxides (NOx):
  • Nitrogen oxides are a group of gases that are composed of nitrogen and oxygen.
  • These are produced from the reaction among nitrogen, oxygen, and even hydrocarbons (during combustion), especially at high temperatures.
  • NOx gases are known to contribute to environmental issues such as smog and acid rain.
• Oxygen Cycle:
  • The oxygen cycle is the biogeochemical cycle that describes the movement of oxygen within and between its three main reservoirs: the atmosphere, the biosphere, and the lithosphere.
  • It involves processes like photosynthesis, respiration, and decomposition.