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Biological Weathering- NCERT Geography Notes For UPSC Exams:
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Biological Weathering is one among important topics for UPSC Civil Services Exam. In this article, we will be covering the meaning of biological weathering, the process involved in it and the causative factors in it.
About Biological Weathering: - The process of removal of minerals and iron from the rock is known as biological weathering. This process brings physical changes in rocks due to growth or movement of organisms.
- For example: organisms like earthworm, algae, termites help in making soil fertile which is directly or indirectly good for agriculture and irrigation processes. Sometimes this process is done by human beings also by ploughing and cultivating processes.
- As by this process they are mixing and creating contact between air, water, soil minerals present on the earth surface. This organism also produces chemicals that absorb all the nutrients from rock and help in the process of rock breaking on which day lives.
- Along with that there are some organisms like Piddock shells who Bole into rocks and scrap away the grains by absorbing nutrient and acid present in the rock which Fossil led to to dissolving of the rock.
- The process of biological weathering is common and can be seen everywhere. There are several organisms like bacteria, algae and lichen which produce chemicals that help in breaking down rock on which day lives.
Check NCERT notes on Endogenic Process here.
Biological Weathering (UPSC Geography) NCERT Notes: Download PDF Here
Process Involved in Weathering of Rocks:
Biological weathering is the process of disintegration of the rock and minerals by various biological agents. This process is caused by the physical or chemical agent of organisms. These agents include:
A. Organic Activity From Lichen And Algae:
Organisms like lichen and algae which are open, live on bare rock extract minerals from the rock by a process called Ion exchange mechanism. This biochemical weathering process of leaching minerals from the rock happens which causes weakening and breakdown of rock. Along with that the king of plant material can also produce acidic compounds which have capability to dissolve the exposed rock. Apart from all these processes, presence of organisms growing pending on moving across the surface of rock also lead to small amounts of abrasion and pressure which led to mechanical weathering of the rock. As in this process the organism extracts various minerals from the rock.
B. Rock Disintegration By Plant Growth:
When plant roots penetrate the rock it then leads to cracks and crevices of rocks. This process leads to the split or break of rock into smaller particles through mechanical weathering. The rate of this process is gradually slower than other weathering processes.
C. Burrowing And Tunneling Organisms:
Borrowing tunneling and asset secreting organism are also considered as another form of biological weathering. As all these organisms chemically or mechanically contribute to the weathering process. This organism Mein Boro or tunnel into rock or cracks into rock that causes The Rock to break down and disintegrate into smaller pieces.
Agents That Cause Biological Weathering
The common agents which cause biological weathering are: humans, plants, wind, water, air, animals, etc. Biological weathering can be further classified into types i.e. mechanical and chemical weathering. Acid rain describes a chemical weathering process.
A. Biological Weathering By Microorganisms:
Organisms which do processes like wedging and burrowing can cause biological weathering processes. Such organisms are: termites, earthworms, rodents, etc. All these organisms help in showing the new surface to chemical attack and also helps in penetration of air and moisture.
Whereas organisms like bacteria, mosses, algae, lichens frequently grow on rock surfaces mainly in humid areas. These organisms form weak acid which has the capability of converting minerals to clay.
Growth of algae can deteriorate several rock types and give them more exposure for the weathering process.
B. Biological Weathering By Humans:
Apart from microorganisms, humans can also play a crucial role in the biological weathering process. As during processes like road building, mining, etc weathering process in occuring. Processes like vegetation, ploughing, cultivation of soil are also helpful in producing new contacts between water, minerals and air in the earth material.
C. Biological Weathering Process By Plants And Animals:
Processes like decomposition of plants and animals helps in creation of different acids like carbonic acids, humic and many more different acids which increase the decay and solubility of some elements. Along with that roots of plants also have the ability of creating tremendous pressure on the earth material and leads to weathering processes.
Check detailed NCERT notes on Weathering here.
Types Of Biological Weathering - Plant roots: There are trees which grow within the rock and such plants lead to biological weathering processes. As the plant roots penetrate the soil for getting nutrients and water and during this process plant roots go through cracks or joints in the rocks and with their growth they crack the root apart. Sometimes roots of bigger plants also exert pressure on adjacent rocks whereas some plants also emit organic acids which have capability of dissolving rocks minerals.
- Microbial activity: Microorganisms like algae, moss, lichens and bacterias have the ability of producing organic acids. This acid by passage of time alters the chemical composition of rocks and also breaks down the outer layer of rock with time.
- Burrowing animals: Animals like moles, rabbits, squirrels have the ability to create fissure into the rocks. Along with that they also sucks important nutrients during this process. Which leads to the breaking down of rocks into big pieces.
- Human activities: Human activities like agricultural practice, mining, construction, etc are involved in fragmentation of rocks into small pieces. As all these activities create cracks in the rock which do the weathering process.
You might also like: NCERT notes on Conservation of Biodiversity
We hope the above NCERT Notes Geography(NCERT) -NCERT Notes On Biological Weathering for UPSC aspirants proves to be useful for your UPSC and other competitive exams preparations. For more notes and updated details, download the Testbook App and get exam-ready in no time!
Biological Weathering FAQs
How do biological weathering processes occur?
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How can we prevent biological weathering processes?
By doing power washing cement or asphalt surfaces along with doing the weeding process regularly can prevent biological weathering processes. As all these surfaces prevent the surface of rocks from decomposition processes which are induced by acids produced by lichens or mosses. Along with that removal of large trees can also prevent biological weathering processes.
What is chemical weathering?
When acid rain and moving water react with rocks and minerals to change or weaken them, such a process is called chemical weathering. Such weathering always causes some type of chemical reaction within the rock or mineral itself.
What are the importance of weathering for the well being of the environment?
One of the major roles of weathering is in the formation of soil. As during the weathering process initial masses of rocks are broken down into small fragments and by there occurs the formation of soil. The extent of weathering of rocks determines the depth of soil.
How can the weathering process be prevented?
By using wind barriers the process as it minimises the weathering activity along with that use sealants such as stains on decks, to prevent the decomposition of such materials.