Nutrient cycle in ecosystem


5 basic nutrients existing in their original form are carbohydrates, proteins, lipids, vitamins, and minerals. Nevertheless, after the consumption of the nutrients, they acquire simpler forms, for instance, carbohydrates become glucose, proteins release amino acids and the complex lipids convert to their simpler forms-triglycerides. This will give us a clue that nutrients experiences some changes once they are consumed in the original forms. In order for the nutrients to attain their simpler forms, they must undergo some cyclic processes such as Kreb`s cycle or  ATP cycle. Similarly, in our atmosphere a number of cycles take place, one such process is the Nutrient cycle. Another distinguished phenomenon to be noted is that, following the utilization of nutrients by the body, the nutrients are transformed into waste material such as ammonia, urea and uric acid. Furthermore, the wastes excreted by our body are no more going to be the end products because they enter into the soil so that the whole cycle repeats. 


Need for nutrition cycles

The movement of nutrients through the various spheres of an ecosystem ( lithosphere, hydrosphere, and biosphere) to change themselves into different forms is called nutrient cycling. Plants help in the conversion of wastes ( by utilizing them as minerals in the form of compost) into essential nutrients such as starch, proteins and minerals. Hence, it is true that energy can neither be created and nor be destroyed but it can only switch into different form. Nutrient cycle is one of the ways in which the energy is converted from one form to another. There are many nutrient cycles in our ecosystems. The very purpose of a nutrient cycle is to convert complex inorganic substances into the usable and simpler form. Hence, nutrient cycle or ecological recycling is the process of exchange and movement of nutrients between their organic to inorganic forms that ultimately help in releasing them into the original production cycle. For example, food is consumed in the form of carbohydrates, protein, fats, but the end products will be urea, uric acid, ammonia which will enter the system once again. We can notice one thing that energy is escaped or trapped but it just gets into another form.


Forms of nutrient cycle 

Nutrient cycles are of 2 forms namely, gaseous form(nitrogen cycle and carbon cycle) and sedimentary form (, Sulfur, and phosphorus cycles). The net amount of nutrients available in their original form (carbon, nitrogen, phosphorus, calcium, etc) is called standing state at that point of time however some nutrients will be utilized for the bodily activities of individuals.  Some of the common nutrient cycles are as described below.


Carbon Cycle 

Earth is a reservoir of a huge amount of carbon in various forms. This is because, carbon is the basic building block of every organic material.  The majority of the carbon is found the oceans (71 %), and some amount in the earth’s crust and the rest of the amount is found within the living organisms. Some of the material goods that we use in our day-to-day life also has carbon, for example, diamond and graphite. Our atmosphere hardly holds 1% of the total carbon. Nevertheless, there is no stable form for carbon, instead, it undergoes a cyclic change from one form to another as shown in the image below.


Diagram of the carbon cycle- source

Carbon cycle


Some of the ways in which carbons moves in various forms are:

1. Photosynthesis: C02 is consumed by the plants during photosynthesis to produce food in the form of organic molecules like glucose. Glucose has some percentage of carbon in its molecular form.

2. Combustion: Through burning the wood, fossils and wastes will be degraded. By this method, the solid carbon is converted into co2 gas.

3.Metabolism: During the metabolic process, autotrophs converts the carbon into organic molecules such as fats, carbohydrates, and proteins and the autotrophs(plants) are consumed by the animals. On the other hand, the heterotrophs-animals consume these organic molecules and release carbon as the end product of excretion.

4. Oceanic life: Oceanic plants such as phytoplankton, zooplankton prey on each other, consequently, as an end product they release the co2 into  the ocean.

5. Cellular respiration: This is a very common way of conversion of carbon in which animals eat plants to consume organic carbon (carbohydrates) and these organic molecules will be broken down in the animal`s body systems with the help of cellular respiration. Ultimately, animals release the energy, water, and carbon dioxide. Furthermore, the same carbon dioxide is returned to the atmosphere during the gaseous exchange.

6. Precipitation of co2: Co2 Present in the atmosphere gets precipitated into solid carbonates in the ocean sediments.

7. The decay of dead matter: Carbon dioxide is released as a gas into the atmosphere during the decay of all organisms.


 Phosphorus Cycle

Posphorus cycle

Phosphorus is mainly present in its organic form inside our body systems. It is also one of the major components of all biological membranes, nucleic acids, etc. It makes up about 1% of our total body weight. Phosphorus is the second most abundant mineral in our body with the majority being found in the bones and teeth. In addition, phosphorus is a primary component in many bodily processes and cellular energy transfer system. In our nature, the natural reservoir of phosphorus is the rock phosphate. During the weathering process, sunlight and rain act on these rocks to dissolve a small amount of rocky phosphate. This will help in allowing the phosphorus to enter the soil. Soil helps the roots of the plants to absorb them and ultimately the herbivores and other animals obtain their phosphorus by eating these plants. When the plants and animals die, the dead organisms have phosphate-solubilizing bacteria to release phosphorus back into the environment. Phosphorus cannot be converted into gaseous form like oxygen and carbon dioxide.


Further reading


Types of ecosystem


Tropic levels in the ecosystem


Succession on the ecosystem


 Introduction to ecosystem



  1. What is a nutrient cycle? explain its importance.

  2. Describe the carbon cycle in detail.

  3. What are the different forms of nutrient cycles? explain one of them with an example.

  4. Explain the phosphorus cycle with a diagram.









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