Bio-geochemical cycles
As the name suggests that it is the cycle of flow of nutrients between biological and geographical components of an ecosystem or environment.
Nutrient Cycle
- The nutrient cycle refers to the process by which essential nutrients are transferred from the physical environment to living organisms and then cycled back to the environment.
Types of Nutrient cycle
Atmospheric Nutrient Cycle
A. Water Cycle.
B. Carbon Cycle.
C. Oxygen Cycle.
Edaphic Nutrients Cycle
A. Nitrogen Cycle.
B. Sulphur Cycle .
C. Phosphorous Cycle
Atmospheric Nutrient Cycle
A.Water Cycle
- The driving force for a water cycle is the solar radiation which is 15% of the total radiation reaching on the earth.
- The hydrologic cycle is the continuous circulation of water in the Earth atmosphere system.
- Water is an essential resource on Earth, and it is stored in various major reservoirs such as oceans, lakes, rivers, soils, glaciers, snowfields, and groundwater.
- The movement of water from one reservoir to another is facilitated by several processes, including evaporation, transpiration, condensation, precipitation, deposition, runoff, infiltration, and groundwater flow.
B.Carbon Cycle
- The carbon cycle involves the movement of carbon through different parts of the Earth's system.
- Carbon dioxide is a critical gas for plants, as they require it for photosynthesis, which allows them to produce carbohydrates that are necessary for their survival and for other organisms.
- Carbon dioxide is released into the atmosphere through the respiration of all living organisms on the planet.
- The Earth's crust also releases carbon, which is present in the form of calcium carbonates (CaCO3) and magnesium carbonates (MgCO3) from the skeletons of marine organisms during the process of mineralization.
- By subsequent weathering these Calcium Carbonates and Magnesium Carbonates get mixed with the soil and add to the soil nutrition.
- In this way ultimately these carbon rich organic matters accumulate in the ecosystems.
- By burning of fossil fuel, coal & wood large amount of carbon dioxide get released to the atmosphere.
- These carbon dioxides get assimilated by the plants.
- The animals consume these carbohydrates, that is the photosynthetic products.
- The carbohydrates consumed, in this way reach to the heterotrophs.
C. Oxygen Cycle
- The Oxygen cycle involves the movement of oxygen through the atmosphere, biosphere, and lithosphere.
- It shows how free oxygen is produced and utilized in each of these areas.
- This process of oxygen movement is essential for the survival of plants, animals, and humans.
- In the atmosphere, oxygen is produced by photosynthesis and released into the air through respiration and decay processes.
- Plants and animals use oxygen for respiration, which releases carbon dioxide back into the atmosphere.
- In the lithosphere, oxygen is locked in minerals and rocks and released into the atmosphere through weathering processes.
- Overall, the oxygen cycle is a vital process that helps to maintain the balance of oxygen in the Earth's ecosystems.
- In the atmosphere the dry air contains 20.94% of oxygen.
- Oxygen is required by all the living organisms for respiration. It is also associated with the moisture content.
Edaphic Nutrients Cycle
A. Nitrogen Cycle
- About 79% of the atmospheric air is Nitrogen.
- Nitrogen is an essential element for all living organisms.
- Biological nitrogen fixation carried on by some bacteria and blue green algae brings the nitrogen of the atmospheric pool into the soil or aquatic bodies from where it is taken up in the biosphere.
Nitrogen Fixation
Process of Nitrogen Fixation
Nitrogen Fixation-> -> Ammonification ( formation of ammonia) and Nitrification (formation of Nitrates) > Denitrification (Nitrate to Nitrogen)
It can be done both by non-biological (physical) and biological way.
I) Non- Biological fixation of Nitrogen-
- It includes fixation of Nitrogen in Industries, Chemical fertilizers, Agricultural activities etc. artificially.
II)Biological Nitrogen Fixation
- Biological Nitrogen Fixation are of two types.
Non-Symbiotic Nitrogen Fixation-
- It is carried out by organisms, who live freely in the soil or water.
- Example- Azobacter, Anabaena, Nostoc, Cycas Coralloid roots, Blue green algae etc.
Symbiotic Nitrogen Fixation-
- Symbiotic nitrogen fixation is a process by which microorganisms live inside the root nodules of various plants in a mutually beneficial relationship.
- These microorganisms possess the ability to convert atmospheric nitrogen into a usable form.
- Primarily found in the roots of legumes, including peas, soybeans, and beans, nitrogen fixing organisms create nodules in the plant's roots, where they multiply and perform the nitrogen fixation process.
- Examples- Bacteria, Rhizobium etc.
III) Ammonification
- It is the process of production of ammonia (NH3) or ammonium (NH4) compounds from the decomposition action of bacteria on organic matter & nitrogenous waste products such as urea and uric acid (organic nitrogen).
- Examples– Nitrosomonas bacteria, Nitroso coccus bacteria.
IV) Nitrification-
- Nitrification is the process of converting ammonium to nitrates.
- The conversion begins when the bacteria Nitrosomonas and/or Nitrococcus oxidize ammonium ions to nitrite.
- Nitrite is then further oxidized to nitrate with the aid of the bacterium Nitrobacter.
V)Denitrification (Nitrate to Nitrogen)
- It is the process of conversion of Nitrate to Nitrogen.
- Examples- Pseudomonas and Thiobacillus Bacteria.
B.Sulphur Cycle
- The movement of sulphur in the biosphere and the underground is called Sulphur Cycle.
- It is found in Rocks, Organic and inorganic deposits etc.
- Sulphur occurs in the form of Hydrogen sulphide (H2S) (both gaseous and sedimentary) Sulphur dioxide (SO2) (both gaseous and sedimentary) Sulphates (SO4) (sedimentary).
- Sulphur enters the atmosphere from several sources like volcanic eruptions, combustion of fossil fuels, from surface of ocean and from gases released by decomposition.
- When atmospheric hydrogen sulphide is oxidized, it transforms into sulphur dioxide.
- Sulphur dioxide in the atmosphere dissolves in rainwater to form weak sulphuric acid and is then carried back to the earth.
- Organic sulphur present in plant and animal bodies is decomposed by aerobic bacteria.
- During decomposition, sulphur in organic matter is transformed into sulphate (SO4) or hydrogen sulphides (H2S).
- Hydrogen Sulphides then get converted into elemental sulphur by anaerobic bacteria (these bacteria do not require oxygen).
- Sulphur Dioxide (SO2) is also released to the atmosphere by vehicular exhaustion.
C.Phosphorus Cycle
- It is the part of one of sedimentary cycle.
- Phosphorous is found MORE in aquatic system as comparison to Land because runoff water brings it to water bodies.
It is found in following ways-
- In Plants and animal bodies.
- In rocks and Natural deposits.
Process-
Absorption of phosphorus by roots of plants from soil ->through food chain it enters to bodies of animals ->after the death of Animals and Plants it goes back to soil.
Important one liner on Bio-geochemical cycles.
What do you understand by bio-geochemical cycles?
Bio-geochemical cycles are a process of nutrient flow between biological and geographical components of an ecosystem.
What is the nutrient cycle?
The nutrient cycle refers to the movement of essential nutrients from the physical environment to living organisms and then back to the environment.
What are the two types of nutrient cycles?
The two types of nutrient cycles are atmospheric and edaphic nutrient cycles.
What are the three types of atmospheric nutrient cycles?
The three types of atmospheric nutrient cycles are the water cycle, carbon cycle, and oxygen cycle.
What is the driving force for the water cycle?
The solar radiation is the driving force for the water cycle.
What are the major reservoirs of water on Earth?
The major reservoirs of water on Earth are oceans, lakes, rivers, soils, glaciers, snowfields, and groundwater.
How is carbon dioxide released into the atmosphere?
Carbon dioxide is released into the atmosphere through the respiration of all living organisms on the planet.
What is mineralization?
Mineralization is the process where calcium carbonates and magnesium carbonates from marine organisms' skeletons mix with soil and add to the soil nutrition.
What are the primary photosynthetic products?
The primary photosynthetic products are carbohydrates.
What is the role of oxygen in the lithosphere?
Oxygen is locked in minerals and rocks in the lithosphere and released into the atmosphere through weathering processes.
What is the percentage of nitrogen in atmospheric air?
About 79% of atmospheric air is nitrogen.
What is biological nitrogen fixation?
Biological nitrogen fixation is a process by which some bacteria and blue-green algae bring atmospheric nitrogen into the soil or aquatic bodies, which is then taken up in the biosphere.
What are the two types of biological nitrogen fixation?
The two types of biological nitrogen fixation are non-symbiotic nitrogen fixation and symbiotic nitrogen fixation.
What is nitrification?
Nitrification is the process of converting ammonium to nitrates.