One of the most pressing Biology Topics of our time is the conservation of endangered species and habitats.
What is Oxygen Cycle? Explain with diagram
Oxygen is one of the constituents of water and forms about 21 percent of the air in the atmosphere. It is required for respiration by all living organisms. Oxygen enters the living world through respiration; it oxidizes the food materials and produces energy and carbon dioxide:
Carbon dioxide (CO2) is utilized by plants to produce food materials during the process of photosynthesis.
The consequent free oxygen may now be used again in respiration or it may return to the environment as molecular oxygen of the atmosphere thus, completing the biogeochemical cycle.
The oxygen cycle. As the oxygen concentration in the atmosphere remains constant at 21 percent it is likely that natural degradation of ozone must occur to maintain the ozone: oxygen equilibrium.
The concentration of oxygen in the air and water is maintained by equal rates of its use in respiration and release in photosynthesis. Oxygen is also released as a part of CO2 by the decomposition of dead organic matter. Some oxygen is added to the air as CO2, H2O, sulphur dioxide (SO2), and nitrogen oxides during the burning of fuels (wood, coal, petroleum, and natural gas).
Some oxides (e.g., nitrate and nitrites) are formed by the microbial oxidation process. These oxides release O2 when reduced by chemical and biological processes. Oxygen is temporarily withdrawn from the circulation when it combines with soil minerals to form their oxides (e.g., when oxygen combines with iron it forms ferric oxide). Some part of the atmospheric oxygen that reacts at the higher levels of the atmosphere is reduced to ozone (O3) by high energy ultraviolet (UV) radiation. The ozone layer forms the protective ozone shield of the atmosphere.
The ozone layer protects organisms by preventing most of the ultraviolet and X-ray from reaching the Earth’s surface. The most recent factor affecting the oxygen cycle of the biosphere and the oxygen budget of the earth is the human being himself, i.e., burning fossil fuels.