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How Does Nature Recycle Nutrients?. What is the Nitrogen Cycle? Facts: Facts: Nitrogen (N) is an essential constituent of protein, DNA, RNA, and chlorophyll.

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Presentation on theme: "How Does Nature Recycle Nutrients?. What is the Nitrogen Cycle? Facts: Facts: Nitrogen (N) is an essential constituent of protein, DNA, RNA, and chlorophyll."— Presentation transcript:

1 How Does Nature Recycle Nutrients?

2 What is the Nitrogen Cycle? Facts: Facts: Nitrogen (N) is an essential constituent of protein, DNA, RNA, and chlorophyll. Nitrogen (N) is an essential constituent of protein, DNA, RNA, and chlorophyll. Nitrogen is the most abundant gas in the atmosphere (78%), but it must be fixed or converted into a usable form. Nitrogen is the most abundant gas in the atmosphere (78%), but it must be fixed or converted into a usable form.

3 How is Nitrogen Fixed? Nitrogen Fixation Methods: Nitrogen Fixation Methods: High energy fixation- a small amount of atmospheric nitrogen is fixed by lightening. The high energy combines N and H 2 O resulting in ammonia (NH 3 ) and nitrates (NO 3 ). These forms are carried to Earth in precipitation. High energy fixation- a small amount of atmospheric nitrogen is fixed by lightening. The high energy combines N and H 2 O resulting in ammonia (NH 3 ) and nitrates (NO 3 ). These forms are carried to Earth in precipitation. Biological fixation: achieves 90% of the nitrogen fixation. Atmospheric nitrogen (N 2 ) is split and combined with hydrogen (H) atoms to eventually form ammonia (NH 3 ). Biological fixation: achieves 90% of the nitrogen fixation. Atmospheric nitrogen (N 2 ) is split and combined with hydrogen (H) atoms to eventually form ammonia (NH 3 ).

4 Who Performs Nitrogen Fixation? Symbiotic bacteria (eg. Rhizobium spp.) living in association with leguminous (plants in the pea/bean family). - free-living anaerobic bacteria - blue-green algae (cyanobacteria) Symbiotic bacteria (eg. Rhizobium spp.) living in association with leguminous (plants in the pea/bean family). - free-living anaerobic bacteria - blue-green algae (cyanobacteria) Ammonification: Once NH 3 is in the soil it combines with H+ ions to form ammonium ion (NH 4 ), or without it to form NO 3. NH 4 + and NO 3 are readily absorbed by plants. Ammonification: Once NH 3 is in the soil it combines with H+ ions to form ammonium ion (NH 4 ), or without it to form NO 3. NH 4 + and NO 3 are readily absorbed by plants. Nitrification: is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates (bacteria) Nitrification: is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates (bacteria) Denitrification: Bacteria reduces nitrates and nitrites back into gaseous nitrogen (N 2 ) Denitrification: Bacteria reduces nitrates and nitrites back into gaseous nitrogen (N 2 )

5 The Nitrogen Cycle

6 What is the Carbon Cycle? All life is based on the element carbon. All life is based on the element carbon. Carbon is the major chemical constituent of most organic matter, from fossil fuels to the complex molecules (DNA and RNA) that control genetic reproduction in organisms. Carbon is the major chemical constituent of most organic matter, from fossil fuels to the complex molecules (DNA and RNA) that control genetic reproduction in organisms. Yet by weight, carbon is not one of the most abundant elements within the Earth's crust. In fact, the lithosphere is only 0.032 % carbon by weight. Yet by weight, carbon is not one of the most abundant elements within the Earth's crust. In fact, the lithosphere is only 0.032 % carbon by weight. In comparison, oxygen and silicon respectively make up 45.2 % and 29.4 % of the Earth's surface rocks. In comparison, oxygen and silicon respectively make up 45.2 % and 29.4 % of the Earth's surface rocks.

7 The Carbon Cycle

8 Where is Carbon Stored Living Organisms (organic molecules) Living Organisms (organic molecules) Sedimentary Rock (limestone, dolomite) Sedimentary Rock (limestone, dolomite) Shells of marine organisms (calcium carbonate) Shells of marine organisms (calcium carbonate) Fossil Fuels Fossil Fuels Carbon Dioxide in our atmosphere Carbon Dioxide in our atmosphere Organic matter in our soils Organic matter in our soils

9 What is the Phosphorus Cycle? Component of DNA, RNA, ATP, proteins and enzymes Component of DNA, RNA, ATP, proteins and enzymes Cycles in a sedimentary cycle - A good example of how a mineral element becomes part of an organism. Cycles in a sedimentary cycle - A good example of how a mineral element becomes part of an organism. The source of Phosphorus (P) is rock. The source of Phosphorus (P) is rock. It is released into the cycle through erosion or mining. It is released into the cycle through erosion or mining. It is soluble in H 2 O as phosphate (PO 4 ) It is soluble in H 2 O as phosphate (PO 4 ) It is taken up by plant roots, then travels through food chains. It is taken up by plant roots, then travels through food chains. It is returned to sediment It is returned to sediment

10 The Phosphorus Cycle

11 What is the Oxygen Cycle?


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