You have studied in Class XI that organisms need a constant supply of nutrients to grow, reproduce and regulate various body functions. The amount of nutrients, such as carbon, nitrogen, phosphorus, calcium, etc., present in the soil at any given time, is referred to as the standing state.
It varies in different kinds of ecosystems and also on a seasonal basis. What is important is to appreciate that nutrients which are never lost from the ecosystems, they are recycled time and again indefinitely.
The movement of nutrient elements through the various components of an ecosystem is called nutrient cycling. Another name of nutrient cycling is biogeochemical cycles (bio: living organism, geo: rocks, air, water).
Nutrient cycles are of two types:
- gaseous and
The reservoir for gaseous type of nutrient cycle (e.g., nitrogen, carbon cycle) exists in the atmosphere and for the sedimentary cycle (e.g., sulphur and phosphorus cycle), the reservoir is located in Earth’s crust. Environmental factors, e.g., soil, moisture, pH, temperaturer etc., regulate the rate of release of nutrients into the atmosphere.
The function of the reservoir is to meet with the deficit which occurs due to imbalance in the rate of influx and efflux. You have made a detailed study of nitrogen cycle in class XI. Here we discuss carbon and phosphorus cycles.