Phosphorous Cycle – Introduction, Steps and Importance

Introduction

Energy flow in ecosystem 

The movement of energy through living creatures in a particular environment is referred to as energy flow. All living organisms can be categorized as producers or consumers, and those producers and consumers are then defined as members of a food chain. A trophic level is the name given to each trophic level in the food chain. The two laws of thermodynamics drive Energy Flow. Energy, according to the First Law, cannot be created or destroyed; it can only change form. According to the Second Law, the more energy that is transmitted, the more energy is wasted. 

Energy flow refers to the quantity of energy that flows through a food chain. The flow of energy is monitored. The energy intake, or energy that enters the environment, measured in Joules or calories. As a result, the energy flow is also known as calorific flow. The Energy Flow is largely responsible for organisms’ survival. The sun is the most important source of energy for all living things. Photosynthesis is the process through which plants transform solar light into energy. This radiation (humans get less than half of the sun’s effective energy) that plants may use is known as Effective Radiation, also known as Photosynthetically Active Radiation (PAR) 

Phosphorus Cycle 

Phosphorus is an essential nutrient for all living creatures. It is an important component of the structural framework of DNA and RNA. They are also a necessary component of ATP. Phosphorus accounts for 80 percent of the phosphorus in human teeth and bones. The phosphorus cycle is an extremely slow process. Phosphorus in the rocks is washed into the soil by a number of weather phenomena. Phosphorus is taken by organic matter in the soil and utilized in a variety of biological activities. Because phosphorus and phosphorus-containing chemicals are solely found on land, the atmosphere plays no part in the phosphorus cycle.  

The phosphorus cycle is a sedimentary cycle (unlike carbon, oxygen, and nitrogen), and neither the atmosphere nor microorganisms fix phosphorus as they do nitrogen. Phosphorus enters the biosphere nearly exclusively through absorption by plant roots in the soil. Weathering of phosphate-containing rocks, primarily apatite [Ca₅(PO₄) 3OH], resulting in a very tiny pool of inorganic phosphorus accessible for organismal usage. 

The majority of phosphorus taken by plants in most soils originates from organic molecules that decompose, releasing phosphorus in plant available inorganic forms. Mineralization is the process by which organically bound nutrients are converted to plant available forms. It is vital in the release of Sulphur, nitrogen, and phosphorus to the soil. Organisms utilize phosphorus in energy transfers (ATP and NAPD), as a component of nucleic acids (RNA and DNA), and as a structural constituent of membranes (phospholipids). 

Phosphorus is a nutrient of concern in most ecosystems due to a combination of three factors: 

• Most soils include only minute quantities of weathering from disjunctly scattered rocks. 
• Being lesser soluble and less mobile than other nutrients, less phosphorus moves in the soil solution. That’s why roots develop in the zone where more phosphorus is available. 
• Phosphorus that flows from the land to the ocean is consumed by creatures in the surface waters, but a significant quantity is lost to sediments in the shells and bones of marine species, as well as via phosphate precipitation and settling. 

Phosphorus cycle steps 

The following are the important steps in the phosphorus cycle process: 

• Weathering  
• Absorption b plants 
• Absorption by animals 
• Return to environment through decomposition. 

1. Weathering 

Phosphorus may be found in abundance in rocks. Because of this, the phosphorus cycle begins in the earth’s crust. The phosphate salts are extracted from the rocks. These salts are washed away into the earth and combine with it. 

2. Absorption by Plants 

Plants absorb phosphate salts that have been dissolved in water. The quantity of phosphorus in the soil, on the other hand, is relatively low. That is why farmers use phosphate fertilizers on their agricultural land. 

Aquatic plants absorb inorganic phosphorus from the bottom layers of bodies of water. Phosphate salts have an effect on plant growth in aquatic environments because they do not dissolve properly in water.  

3. Absorption by Plants 

Phosphorus is absorbed by animals through plant consumption or by devouring plant-eating animals. When opposed to rocks, plants and animals have a quicker phosphorus cycle. 

4. Return of Phosphorus Back to the Ecosystem 

When plants and animals die, bacteria degrade them. The organic form of phosphorus is transformed into the inorganic form, which is returned to soil and water throughout this process. 

Soil and water will end up in sediments and rocks, which will then weather and release phosphorus. As a result, the phosphorous cycle begins once more. 

Human impacts on phosphorus cycle 

A variety of human activities, including as fertilizer usage, artificial eutrophication, and so on, have a significant influence on the phosphorus cycle. Phosphorus fertilizers raise the phosphorus level in the soil. Excessive use of these fertilizers lowers soil fertility and is also detrimental to soil microbes. When they are carried away into neighboring bodies of water, they endanger aquatic life. The quantity of phosphorus carried away in water during the transportation of food from farms to cities promotes eutrophication. This promotes the growth of algae. These either create algal blooms or perish, both of which are hazardous to the aquatic habitat. 

Importance of carbon cycle 

Phosphorus is a necessary element for all living species since it is a structural component of ATP (adenosine triphosphate), a type of cellular energy, as well as DNA and RNA, which are vital life-sustaining molecules. Phosphorus is found in the human body in the form of bones and teeth, which account for 80 percent of the phosphorus need. Because of its scarcity in soil and water, phosphorus restricts plant and animal development. 

The phosphorus in these rocks is progressively degrading, releasing phosphates into the environment or draining into the sea, where it is deposited in deep sediments. The ratio of phosphorus to other elements in the body is larger than the accessible and primary sources of phosphorus. It is a more crucial and limiting factor in terms of production. Thus, the phosphorus cycle is recognized as a crucial ecological cycle.