Biogeochemical Cycling

Environmental science Module 1 Topic. This PPT is not a work of mine and was provided by our college professor during our graduation, so I am not sure about the original author. The credit goes to the Original author.

1. Biogeochemical cycle Biogeochemical cycle involves biological, geological and chemical system and all are interlinked through a cyclic chain. It is a complete pathway that a chemical element flows from atmosphere, water, rock or soils to the living organisms and again back to the atmosphere, water, rock or soils from living organisms The cyclic pathways through which continuous circulation of the chemical substances take place from abiotic components to the living organisms and from living organisms to abiotic components are called biogeochemical cycles. The most important cycles are water, carbon, oxygen, nitrogen and phosphorus

2. Hydrological cycle (water cycle) Clouds Evaporation Soil Ground water infiltration snow melting precipitation rainfall ocean evaporation & condensation Water bodies

3. Water cycle It is a continuous natural process. The cyclic movement of water as it evaporates from land, water and living organisms enters the atmosphere where it condenses and back to living organisms on the earth’s surface as precipitation From the earth’s surface it moves under ground by infiltration or overland by surface runoff into rivers, lakes and oceans. The total amount of water on earth remains constant but due to hydrological cycle it moves from one place to another. The movement and flow of water takes place continuously through the natural process like evaporation , condensation , runoff , sublimation , transpiration and infiltration

4. Oxygen cycle Atmospheric O2 Respiration in animals & plants Photosynthesis in green plants CO2 + H2O Organic compd

5. Oxygen is the major component of all living organisms. Oxygen is needed by most of the plants & animals & all human beings for aerobic respiration The plants & animals can take O2 from atmosphere through respiration process & through photosysnthesis . The plant releases O2 into the atmosphere. This continuous exchange of O2 between the atmosphere & living organisms set up the O2 cycle.

6. Carbon Cycle Carbon is the basic ncomponent of organic compounds such as carbohydrates, proteins, lipids etc which are present in all living organisms. Carbon is present in atmosphere as CO2. Green plants uses CO2 during photosysnthesis & produce carbohydrates. Consumers take up carbohydrates & synthesise C compounds in their body. When producers & consumers die , the body is decomposed by the action of microorganisms producing CO2 which enters to atmosphere. Dead organic matter is converted into fossil fuels from which coal,oil & gas are produced.

7. Carbon Cycle These on combustion form CO2 & release to the atmosphere. Thus the continuous exchange of CO2 between atmosphere & living organisms forms Carbon cycle.

8. Carbon cycle Atmospheric CO2 decompose respiration Dead organic matter Consumer producer death death Fossil fuel Fossil fuel combustion

9. Nitrogen cycle Atmospheric N2 Animal protein Nitrogen fixation NO2 in soil & water NO3 in soil & water P lant protein NH3 in soil & water denitrification decomposers nitrification ammonification

10. Nitrogen Cycle It is a process of exchange of N2 in the form of NH4 + , NO2, NO3 through the biotic & abiotic components of an ecosystem, It consists of the following steps : i ) Nitrogen fixation i i) assimilation i ii) ammonification i v) nitrification v ) denitrification Nitrogen fixation : It is the process of conversion of atmospheric N2 to ammonia (NH3) by soil bacteria N2+ 3 H2 2NH3

11. Nitrogen Cycle Ammonification : It is the conversion of organic form of N2 ( Protein, Amminoacid ) to ammonia by bacteria & fungi Nitrification : It is the process of conversion of NH3 into nitrites (NO2 - ) & then nitrates (NO3- ) Denitrification : It is the process where nitrate & nitrite is converted to N2

12. Phosphorus Cycle Ammonification : It is the conversion of organic form of N2 ( Protein, Amminoacid ) to ammonia by bacteria & fungi Nitrification : It is the process of conversion of NH3 into nitrites (NO2 - ) & then nitrates (NO3- ) Denitrification : It is the process where nitrate & nitrite is converted to N2