🔆BIO-GEOCHEMICAL CYCLE
✅The movement of nutrient elements through the various components of an ecosystem is called nutrient cycling.
✅Another name of nutrient cycling is biogeochemical cycles (bio: living organism, geo: rocks, air, water). Nutrient cycles are of two types:
1. Gaseous - Reservoir for gaseous type of nutrient cycle (e.g. nitrogen, carbon cycle) exists in the atmosphere
2. Sedimentary- For the sedimentary cycle (e.g. Sulphur and phosphorus cycle), the reservoir is located in Earth’s crust.
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✅The movement of nutrient elements through the various components of an ecosystem is called nutrient cycling.
✅Another name of nutrient cycling is biogeochemical cycles (bio: living organism, geo: rocks, air, water). Nutrient cycles are of two types:
1. Gaseous - Reservoir for gaseous type of nutrient cycle (e.g. nitrogen, carbon cycle) exists in the atmosphere
2. Sedimentary- For the sedimentary cycle (e.g. Sulphur and phosphorus cycle), the reservoir is located in Earth’s crust.
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🔆Carbon Cycle:
✅ 71 per cent carbon is found dissolved in oceans. This oceanic reservoir regulates the amount of carbon dioxide in the atmosphere.
✅Atmosphere only contains about 1 per cent of total global carbon.
✅Carbon cycling occurs through atmosphere, ocean and through living and dead organisms.
✅ A considerable amount of carbon returns to the atmosphere as CO2 through respiratory activities of the
producers and consumers.
✅Decomposers also contribute substantially to CO2 pool by their processing of waste materials and dead
organic matter of land or oceans.
✅Human activities have significantly influenced the carbon cycle. Rapid deforestation and massive burning of fossil fuel for energy and transport have significantly increased the rate of release of carbon dioxide into the
atmosphere.
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✅ 71 per cent carbon is found dissolved in oceans. This oceanic reservoir regulates the amount of carbon dioxide in the atmosphere.
✅Atmosphere only contains about 1 per cent of total global carbon.
✅Carbon cycling occurs through atmosphere, ocean and through living and dead organisms.
✅ A considerable amount of carbon returns to the atmosphere as CO2 through respiratory activities of the
producers and consumers.
✅Decomposers also contribute substantially to CO2 pool by their processing of waste materials and dead
organic matter of land or oceans.
✅Human activities have significantly influenced the carbon cycle. Rapid deforestation and massive burning of fossil fuel for energy and transport have significantly increased the rate of release of carbon dioxide into the
atmosphere.
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#bio_geochemical_cycle
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🔆Nitrogen Cycle:
✅ Nitrogen is a constituent of amino acids, proteins, hormones, chlorophylls and many of the vitamins
✅Plants compete with microbes for the limited nitrogen that is available in the soil. Thus, nitrogen is a limiting nutrient for both natural and agricultural ecosystems.
✅ Nitrogen exists as two nitrogen atoms (N2) joined by a very strong triple covalent bond (N ≡ N).
✅ In nature, lightning and ultraviolet radiation provide enough energy to convert nitrogen to nitrogen oxides (NO, NO2, N2O).
✅ Industrial combustions, forest fires, automobile exhausts and power-generating stations are also sources of atmospheric nitrogen oxides.
1. Step 1: N2 Fixing ➔ Nitrogen → Ammonia or Ammonium Ions
2. Step 2: Nitrification ➔ Ammonia or Ammonium Ions (bacteria: Nitrosomonas and/or Nitrococcus) → Nitrite (Nitrobacter)→ Nitrate
3. Step 3: Ammonification ➔ Dead Matter + Animal Waste (Urea, Uric Acid) → Ammonia or Ammonium Ions
4. Step 4: Denitrification ➔ Nitrate (bacteria: Pseudomonas and Thiobacillus) → Nitrogen
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✅ Nitrogen is a constituent of amino acids, proteins, hormones, chlorophylls and many of the vitamins
✅Plants compete with microbes for the limited nitrogen that is available in the soil. Thus, nitrogen is a limiting nutrient for both natural and agricultural ecosystems.
✅ Nitrogen exists as two nitrogen atoms (N2) joined by a very strong triple covalent bond (N ≡ N).
✅ In nature, lightning and ultraviolet radiation provide enough energy to convert nitrogen to nitrogen oxides (NO, NO2, N2O).
✅ Industrial combustions, forest fires, automobile exhausts and power-generating stations are also sources of atmospheric nitrogen oxides.
1. Step 1: N2 Fixing ➔ Nitrogen → Ammonia or Ammonium Ions
2. Step 2: Nitrification ➔ Ammonia or Ammonium Ions (bacteria: Nitrosomonas and/or Nitrococcus) → Nitrite (Nitrobacter)→ Nitrate
3. Step 3: Ammonification ➔ Dead Matter + Animal Waste (Urea, Uric Acid) → Ammonia or Ammonium Ions
4. Step 4: Denitrification ➔ Nitrate (bacteria: Pseudomonas and Thiobacillus) → Nitrogen
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🔆Sulfur cycle
✅In Sulfur cycle, there is a circulation of sulfur in various forms through nature. Sulfur occurs in all living matter as a component of certain amino acids.
✅ It is abundant in the soil in proteins and, through a series of microbial transformations, ends up as sulfates usable by plants.
✅The Sulphur reservoir is in the soil and sediments where it is locked in organic (coal, oil and peat) and inorganic deposits (pyrite rock and Sulphur rock) in the form of sulphates, sulphides and organic Sulphur.
✅ It is released by weathering of rocks, erosional runoff and decomposition of organic matter and is carried to terrestrial and aquatic ecosystems in salt solution.
✅The Sulphur cycle is mostly sedimentary except two of its compounds, hydrogen sulphide (H2S) and Sulphur dioxide (SO2), which add a gaseous component.
✅Sulphur enters the atmosphere from several sources like volcanic eruptions, combustion of fossil fuels (coal, diesel etc.), from the surface of the ocean and gases released by decomposition.
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✅In Sulfur cycle, there is a circulation of sulfur in various forms through nature. Sulfur occurs in all living matter as a component of certain amino acids.
✅ It is abundant in the soil in proteins and, through a series of microbial transformations, ends up as sulfates usable by plants.
✅The Sulphur reservoir is in the soil and sediments where it is locked in organic (coal, oil and peat) and inorganic deposits (pyrite rock and Sulphur rock) in the form of sulphates, sulphides and organic Sulphur.
✅ It is released by weathering of rocks, erosional runoff and decomposition of organic matter and is carried to terrestrial and aquatic ecosystems in salt solution.
✅The Sulphur cycle is mostly sedimentary except two of its compounds, hydrogen sulphide (H2S) and Sulphur dioxide (SO2), which add a gaseous component.
✅Sulphur enters the atmosphere from several sources like volcanic eruptions, combustion of fossil fuels (coal, diesel etc.), from the surface of the ocean and gases released by decomposition.
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🔆Phosphorus Cycle:
✅Phosphorus is a major constituent of biological membranes, nucleic acids and cellular energy transfer systems.
✅Many animals also need large quantities of this element to make shells, bones and teeth.
✅ The natural reservoir of phosphorus is rock, which contains phosphorus in the form of phosphates.
✅When rocks are weathered, minute amounts of these phosphates dissolve in soil solution and are absorbed by the roots of the plants.
✅Herbivores and other animals obtain this element from plants. The waste products and the dead organisms are decomposed by phosphate-solubilizing bacteria releasing phosphorus.
✅Unlike carbon cycle, there is no respiratory release of phosphorus into atmosphere.
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✅Phosphorus is a major constituent of biological membranes, nucleic acids and cellular energy transfer systems.
✅Many animals also need large quantities of this element to make shells, bones and teeth.
✅ The natural reservoir of phosphorus is rock, which contains phosphorus in the form of phosphates.
✅When rocks are weathered, minute amounts of these phosphates dissolve in soil solution and are absorbed by the roots of the plants.
✅Herbivores and other animals obtain this element from plants. The waste products and the dead organisms are decomposed by phosphate-solubilizing bacteria releasing phosphorus.
✅Unlike carbon cycle, there is no respiratory release of phosphorus into atmosphere.
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🔆Nitrogen Cycle:
✅ Nitrogen is a constituent of amino acids, proteins, hormones, chlorophylls and many of the vitamins
✅Plants compete with microbes for the limited nitrogen that is available in the soil. Thus, nitrogen is a limiting nutrient for both natural and agricultural ecosystems.
✅ Nitrogen exists as two nitrogen atoms (N2) joined by a very strong triple covalent bond (N ≡ N).
✅ In nature, lightning and ultraviolet radiation provide enough energy to convert nitrogen to nitrogen oxides (NO, NO2, N2O).
✅ Industrial combustions, forest fires, automobile exhausts and power-generating stations are also sources of atmospheric nitrogen oxides.
1. Step 1: N2 Fixing ➔ Nitrogen → Ammonia or Ammonium Ions
2. Step 2: Nitrification ➔ Ammonia or Ammonium Ions (bacteria: Nitrosomonas and/or Nitrococcus) → Nitrite (Nitrobacter)→ Nitrate
3. Step 3: Ammonification ➔ Dead Matter + Animal Waste (Urea, Uric Acid) → Ammonia or Ammonium Ions
4. Step 4: Denitrification ➔ Nitrate (bacteria: Pseudomonas and Thiobacillus) → Nitrogen
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✅ Nitrogen is a constituent of amino acids, proteins, hormones, chlorophylls and many of the vitamins
✅Plants compete with microbes for the limited nitrogen that is available in the soil. Thus, nitrogen is a limiting nutrient for both natural and agricultural ecosystems.
✅ Nitrogen exists as two nitrogen atoms (N2) joined by a very strong triple covalent bond (N ≡ N).
✅ In nature, lightning and ultraviolet radiation provide enough energy to convert nitrogen to nitrogen oxides (NO, NO2, N2O).
✅ Industrial combustions, forest fires, automobile exhausts and power-generating stations are also sources of atmospheric nitrogen oxides.
1. Step 1: N2 Fixing ➔ Nitrogen → Ammonia or Ammonium Ions
2. Step 2: Nitrification ➔ Ammonia or Ammonium Ions (bacteria: Nitrosomonas and/or Nitrococcus) → Nitrite (Nitrobacter)→ Nitrate
3. Step 3: Ammonification ➔ Dead Matter + Animal Waste (Urea, Uric Acid) → Ammonia or Ammonium Ions
4. Step 4: Denitrification ➔ Nitrate (bacteria: Pseudomonas and Thiobacillus) → Nitrogen
#revision_notes
#prelims
#environment
#bio_geochemical_cycle
Join @CSE_EXAM
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