Biogeochemical cycles

In Earth science, a biogeochemical cycle or substance turnover or cycling of substances is a pathway by which a chemical substance moves through both the biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) components of Earth.

1. Biogeochemical Cycles MADE BY : DEEPANSHU & HARIKANT PROJECT GUIDE: DR. TANUJA NAUTIYAL DEPT OF CHEMISTRY NORTHERN INDIA ENGINEERING COLLEGE

2. Biogeochemical Cycles Biogeochemical Cycles Describe The Flow Of Essential Elements From The Environment Through Living Organisms And Back Into The Environment.

3. What are biogeochemical cycles? Earth system has four parts Atmosphere Hydrosphere Lithosphere Biosphere Biogeochemical cycles : The chemical interactions (cycles) that exist between the atmosphere, hydrosphere, lithosphere, and biosphere. Abiotic (physio-chemical) and biotic processes drive these cycles Focus on carbon and water cycles (but could include all necessary elements for life). N - cycle weakly touched on!

4. How do elements move through the biogeochemical cycle? 4 Elements Organisms use elements as nutrients and put nutrients back into the environment Elements Elements travel among air, land and sea through physical processes

5. Types Of Biogeochemical Cycles Different types of biogeochemical cycles are as follows : Hydrological cycle Carbon cycle Nitrogen cycle Phosphorus cycle

6. Transformations Examples of Transformations Carbon cycle : Organic compounds to CO 2 (processes: respiration, decomposition, or fire) Carbon cycle : CO 2 to organic compounds (process: photosynthesis) Nitrogen cycle : N 2 to NO 3 (atmospheric nitrogen to plant utilizable nitrate) (process: N-fixation) Nitrogen cycle : N 2 to NH 3 (plant utilizable ammonia) (process: Haber-Bosch Industrial N-fixation) Water cycle : Liquid water to water vapor (process: evaporation and evapo-transpiration) Water cycle : Water vapor to liquid water (process: condensation)

7. Hydrological Cycle

8. Hydrological Cycle 1 1. Reservoir – oceans, air (as water vapor), groundwater, lakes and glaciers; evaporation, wind and precipitation (rain) move water from oceans to land. 2. Assimilation – plants absorb water from the ground, animals drink water or eat other organisms which are composed mostly of water. 3. Release – plants transpire, animals breathe and expel liquid wastes.

9. Carbon Cycle

10. Carbon Cycle (carbon is required for building organic compounds) 1. Reservoir – atmosphere (as CO 2 ), fossil fuels (oil, coal), durable organic materials (for example: cellulose). 2. Assimilation – plants use CO 2 in photosynthesis; animals consume plants. 3. Release – plants and animals release CO 2 through respiration and decomposition; CO 2 is released as wood and fossil fuels are burned.

11. Carbon Cycle 1. Reservoir – atmosphere (as CO 2 ), fossil fuels (oil, coal), durable organic materials (for example: cellulose). 2. Assimilation – plants use CO 2 in photosynthesis; animals consume plants. 3. Release – plants and animals release CO 2 through respiration and decomposition; CO 2 is released as wood and fossil fuels are burned.

12. Carbon Cycle : Key Points Carbon is the skeleton of all life. Carbon dioxide is a critical gas: Taken up by plants in photosynthesis Released by plants and animals in respiration Released during decomposition (and fires) Greenhouse gas (greenhouse effect - your car in the sun)

13. Nitrogen Cycle

14. Nitrogen Cycle 1. Reservoir – atmosphere (as N 2 ); soil (as NH 4 + or ammonium, NH 3 or ammonia, N0 2 - or nitrite, N0 3 - or nitrate 2. Assimilation – plants absorb nitrogen as either NH 4 + or as N0 3 - , animals obtain nitrogen by eating plants and other animals. 3. Release – Denitrifying bacteria convert N0 3 - back to N 2 ; detrivorous bacteria convert organic compounds back to NH 4 + ; animals excrete NH 4 + , urea, or uric acid.

15. Nitrogen Cycle: Key Points Nitrogen is in the atmosphere as N 2 (78%) N 2 is an inert gas and cannot be used by plants or animals N 2 can be converted to a usable form via Lightening N-fixing plants and cyanobacteria Industrial process (energy intensive) Nitrogen limits plant growth Nitrogen is easily lost from biological systems

16. Phosphorus Cycle

17. Phosphorus Cycle Reservoir – erosion transfers phosphorus to water and soil; sediments and rocks that accumulate on ocean floors return to the surface as a result of uplifting by geological processes Assimilation – plants absorb inorganic PO 4 3- (phosphate) from soils; animals obtain organic phosphorus when they plants and other animals Release – plants and animals release phosphorus when they decompose; animals excrete phosphorus in their waste products