Sivasankaran_ppt_20250325_164726_0000[1] [Read-Only].pptx

The nitrogen cycle is the process of nitrogen moving through the atmosphere, soil, water, plants, animals, and microorganisms. It involves:

1. Nitrogen Fixation – Conversion of atmospheric nitrogen into usable forms by bacteria or lightning.


2. Nitrification – Conversion of ammonia into nitrates by bacteria.


3. Assimilation – Plants absorb nitrates for growth.


4. Ammonification – Decomposers convert organic nitrogen from dead organisms into ammonia.


5. Denitrification – Bacteria convert nitrates back into atmospheric nitrogen (N₂), completing the cycle.

1. Sub Title: Nitrogen Cycle Sub Code: WMBM41 (Core) Title: Air Borne Disease Unit: III Here is where your presentation begins Submitted To ; Dr. S. Viswanathan, M.Sc, Ph.D., Head and Associate Professor, PG and Research Department of Microbiology, Sri Paramakalyani College, Alwarkurichi-627412. Submitted By ; SIVASANKARAN. M , II, M.Sc, Microbiology, PG and Research Department of Microbiology, Sri Paramakalyani College, Alwarkurichi-627412. Seminar Assigned Date; 10-01-2025 Seminar Completion Date; 27-02-2025

2. AIM The aim of the nitrogen cycle is to convert nitrogen into various chemical forms that can be used by living organisms. It ensures the continuous movement of nitrogen between the atmosphere, soil, water, and living beings, supporting plant growth, maintaining ecosystem balance, and sustaining life on Earth. OBJECTIVES The nitrogen cycle's objectives are to convert atmospheric nitrogen into usable forms, support plant growth, recycle nitrogen within ecosystems, decompose organic matter, and regulate nitrogen levels to prevent environmental imbalance.

3. Biogeochemical cycle Nitrogen Forms of nitrogen Uses of nitrogen Nitrogen cycle Process of nitrogen cycle Role of nitrogen cycle Importance of nitrogen cycle SYNOPSIS

4. BIOGEOCHEMICAL CYCLE In geography and Earth science, a biogeochemical cycle or cycling of a substance is a pathway by which a chemical substance moves through biotic(biosphere) and abiotic (lithosphere, atmosphere and hydrosphere) compartments of Earth. There are biogeochemical cycles for nitrogen, carbon, phosphorous, sulfur, oxygen and water.

5. BIOGEOCHEMICAL CYCLE

6. NITROGEN Nitrogen is found to have either 3 or 5 valence electron. Lies at the top of group 15 on periodic table. Molecular nitrogen is not reactive at standard temperature and pressure. Nitrogen is a non-metal, colorless, odorless. Largest source of nitrogen is in the atmosphere. Nitrogen makes up 78% of our air! Nitrogen is an essential component. Discovered by Scottish physician Daniel Rutherford in 1772 .

7. FORMS OF NITROGEN It in the form of dinitrogen (N2) gas. In addition to dinitrogen other organic and inorganic forms exist. Organic form of nitrogen make up a very high percentage of the total nitrogen. Plants are able to use only very specific inorganic forms of nitrogen. It is present in the form of organic nitrogen, ammonia, ammonium, nitrite, nitrate, nitrous oxide, nitric oxide or inorganic nitrogen

8. FORMS OF NITROGEN a) organic nitrogen as- ■ ammonium (NH4+), ■ nitrite (NO₂), ■ nitrate (NO3), ■ nitrous oxide (N₂O), ■ nitric oxide (NO) or b) inorganic nitrogen as nitrogen gas (N2).

9. USES OF NITROGEN Food preservation Manufacturing Fire suppression Pharmaceuticals Food packaging Pressurized beer kages

10. NITROGEN CYCLE The nitrogen cycle is a biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among the atmosphere, terrestrial and marine environment. This conversion can be done by both physical and biological methods. It is of particular interest to Ecologists. Nitrogen availability can effect rate of key ecosystem process, including decomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers and release of nitrogen in waste water.

11. PROCESS OF NITROGEN CYCLE Nitrogen cycle consists of the following steps- 1. Nitrogen Fixation 2. Nitrogen assimilation 3. Ammonification 4. Nitrification and 5. Denitrification 6. Sedimentation

12. 1. NITROGEN FIXATION Conversion of nitrogen to nitrates and nitrites through atmosphere, industrial and biological process is called as nitrogen fixation. But most fixation is done by free-living or symbiotic bacteria known as Diazotrophs. These bacteria have the nitrogenase enzyme.

13. TYPES OF NITROGEN FIXATION

14. SYMBIOTIC NITROGEN FIXATION • Nitrogen reduction by symbiotic microbes. • The diazotrophs derive nourishment from plant root and provide nitrogen to it. • These process to form nodule development. • Eg: Rhizobium, Frankia etc.

15. NON SYMBIOTIC NITROGEN FIXATION Some microorganisms live independently in the soil and do nitrogen fixation. Nitrogen fixation by these microbes is called non- symbiotic nitrogen fixation. Non- symbiotic nitrogen fixers are divided into two group Free living autotrophic diazotrophs: synthesize own food by photosynthesis using sunlight or chemicals Eg: Clyndrospermum, Plectonema, Tolupotrix. Free living heterotrophic diazotrophs: Use organic matter as food and do nitrogen fixation. Eg: Clostridium, Azotobacter, Klebsiella, Beijrinckia

16. 2. ASSIMILATION It is the incorporation of inorganic nitrogen compounds into organic molecules. Nitrates and ammonia resulting from nitrogen fixation are assimilated or incorporated into the specific tissue. In plants that have symbiotic relationship rhizobia, nitrogen a with is assimilated in the form of ammonium ions directly from roots.

17. 3. AMMONIFICATION The remains of all living thing and their waste products are decomposed by microorganisms in the process of ammonification which yields ammonia from organic nitrogen. Ammonia can leave the soil or be converted into other nitrogen compounds depending on part of soil condition.

18. The conversion of ammonium to nitrate is performed mainly by the Nitrifying bacteria. In the primary stage of nitrification, the oxidation of ammonium to nitrate is performed by Nitrosomonas sps. which converts ammonia to nitrites. Other bacterial species such as Nitrobacter responsible for the oxidation of the nitrities to nitrates. Ammonia gas is toxic to plants. 4. NITRIFICATION

19. Denitrification is the reduction of nitrates back into nitrogen gas (N2), completing the nitrogen cycle. This process is performed by bacterial species such as Pseudomonas and Clostridium in anaerobic conditions. They use the nitrate as an electron acceptor in the place of oxygen during respiration. Denitrification occurs in anaerobic conditions. 5. DENITRIFICATION

20. 5. DENITRIFICATION

21. Sometimes, nitrates of soil are locked up in the rocks while they are washed down to the sea or leached deeply into the earth along with percolating water. This phenomena is known as sedimentation. 6. SEDIMENTATION

22. 1) Nitrogen fixation through symbiotic relationship. 2) Bacteria break down proteins through the process by decay. 3) Nitrosomonas and nitrobacter help in nitrification. 4) Anamox, Pseudomonas or clostridia help in denitrification. ROLE OF MICROBES IN NITROGEN CYCLE

23. • Plant growth: Nitrogen helps plants grow, produce seeds and fruit, and improve leaf quality. • Soil quality: Nitrogen-rich soil is better for growing crops. • Genetic material: Nitrogen is a key part of DNA, which carries genetic information. • Protein synthesis: Nitrogen is a key part of proteins, which are responsible for many life processes. • Environment: The nitrogen cycle helps clean up the environment by breaking down dead plants and animals. IMPORTANCE OF NITROGEN CYCLE

24. https://www.slideshare.net/slideshow/nitrogen-cycle-42012967/42012967 https://www.slideshare.net/slideshow/nitrogen-cycle-101750973/101750973 https://kids.frontiersin.org/articles/10.3389/frym.2019.00041 REFERENCE

25. LEARNING OUTCOMES Nitrogen Transformation – Understand how nitrogen changes into different forms. Key Processes – Identify stages like fixation, nitrification, and denitrification. Role of Microorganisms – Learn how bacteria help in nitrogen recycling. Importance for Life – Explain how the cycle supports ecosystems and food production. Human Impact – Analyze how human activities affect the nitrogen cycle.

26. EMPOWERING MY POTENTIAL 1. Boosts my confidence in communic complex ideas and opinions. 2. Helps me develop critical thinking self-reflection skills, making me a more informed and thoughtful individual. 3. Enhances my time management and organizational skills as I prepare and deliver the semina

27. SWOT Analysis Opportunities 1. Integration with sustainable development goals
2. Advances in technology
3. Increased public awareness
4. Capacity building and training Threats 1. Lack of political will
2. Limited resources
3. Conflicting interests
4. Climate change and uncertainty Strengths 1. Proactive approach
2. Holistic consideration
3. Improved decision-making
4. Enhanced public participation Weaknesses 1. Time-consuming and costly
2. Limited scope
3. Subjective interpretations
4. Inadequate enforcement

28. MORAL STORY The Drunkard A policeman sees a drunk man searching for something under a streetlight and asks what the drunk has lost. He says he lost his keys and they both look under the streetlight together. After a few minutes the policeman asks if he is sure he lost them here, and the drunk replies, no, and that he lost them in the park. The policeman asks why he is searching here, and the drunk replies, “this is where the light is”. The moral of the story: Truth and wisdom are found where you least want to look.

29. THANK YOU!