What is meant by the cycling of materials in an ecosystem? Describe the carbon cycle in detail with the help of a suitable diagram.

What is meant by the cycling of materials in an ecosystem?
 Describe the carbon cycle in detail with the help of a suitable diagram.

Cycling of materials - Living organisms require four nutrients in relatively large amounts, these are carbon. oxygen, nitrogen, and hydrogen. They also require phosphorus and sulphur. These elements are present in our environment in a fixed quantity, therefore they must be recycled in order to sustain life. Also, these elements must move efficiently, from the living to non-living components and vice versa.

For example, plants take in carbon as carbon dioxide to produce food. As the herbivores eat plants, carbon is passed on to them, which in turn is passed on to carnivores, and so on.

Carbon is eventually returned to the nonliving pool in the ecosystem, through the excretory processes of the producers, the herbivores. the carnivores, and also through the activity of the decomposers. Through such cyclic processes, these nutrients are used over and over again by the organisms. This aspect of the ecosystem function is called the cycling of materials.

Carbon is one of the essential elements of all organic substances and it enters the ecosystem through the process of photosynthesis. Carbon is present as carbon dioxide in the atmosphere. Carbon dioxide forms 0.03 to 0.04% of the atmosphere. The oceans also have carbon dioxide dissolved in their water.

There are 12 basic steps of the Carbon cycle.

1. Carbon dioxide enters the food chain through the plants by the process of photosynthesis.

2. Some of the carbon dioxide captured by the plants and converted into organic molecules are returned to the atmosphere via respiration.

3.  Some portion of the carbon is incorporated into the plant body, which is later passed on to the herbivores, etc.

4.  The living beings release carbon dioxide into the air during breathing.

5.  (i, ii) carbon dioxide is also returned to the atmospheric reservoir by the death and subsequent decay of the dead bodies and wastes of animals and plants.

6)  Formation of fossil fuels, like coal. oil. gas is a part of the carbon cycle, wherein carbon is trapped for millions of years. Fossil fuels are the remains of ancient plants and animals that were subjected to high temperature and pressure over millions of years. Man has been using wood, peat, coal, and petroleum as sources of energy, for running transport such as motorcars, airplanes, etc.: for industries. for cooking food and various other purposes. The burning of fossil fuels returns carbon back into the atmosphere.

7)  Since air is in direct contact with the sea, the carbon dioxide from the air dissolves in the upper layers of water resulting in the formation of carbonates.

8) The plants that grow in seawater, do not get atmospheric carbon dioxide. Therefore, they utilize carbonates present in water as a source of carbon dioxide during photosynthesis.

9)   Food produced by water plants passes through the aquatic food chain. For example, when fish feed on the water plants, carbon passes on from plants to the fish, and ultimately to the other organisms that feed on fish.

10)  Some of the carbon dioxide produced by marine plants and animals during breathing gets dissolved in seawater and can be re-utilized by the plants.

II )  However, some of the carbon dioxides thus evolved escapes to the atmosphere.

12) Organisms like snails, oysters, etc. extract carbon dioxide dissolved in water and combine it with calcium to form calcium carbonate from which they construct their shells. Shells of these dead animals collect in undersea deposits and may eventually be converted to limestone.