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Biogeochemical Cycles. Ecosystem defined: a community of organisms and it’s corresponding abiotic environment through which matter cycles and energy flows.

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Presentation on theme: "Biogeochemical Cycles. Ecosystem defined: a community of organisms and it’s corresponding abiotic environment through which matter cycles and energy flows."— Presentation transcript:

1 Biogeochemical Cycles

2 Ecosystem defined: a community of organisms and it’s corresponding abiotic environment through which matter cycles and energy flows Wide variation in ecosystems Common to all ecosystems: energy flow and cycling of matter

3 Reservoir chemicals for long periods of time in one place and are generally abiotic Example: coal deposits

4 Exchange Pools chemicals are held for only short periods of time and are generally biotic Example: plants and animals (which temporarily use carbon in their systems and then release back into the air)

5 Biogeochemical Cycle pathway by which a chemical element or molecule moves through both biotic ("bio-") and abiotic ("geo-") compartments of an ecosystem. In effect, the element is recycled

6 BIO Biology. Life. Living things. These cycles all play a role in the lives of living things.

7 GEO Earth. Rocks. Land. This refers to the non-living processes at work. Oxygen cycles through many systems. It's in you and plants for the 'bio' part of the cycle. Oxygen might also wind up in rocks. The 'geo' part of its cycle.

8 Chemical Molecules. Reactions. Atoms. All cycles include these small pathways. Complete molecules are not always passed from one point to the next. Sometimes chemical reactions take place that changes the molecules and locations of the atoms.

9 What are the main cycles? In a gas cycle elements move through the atmosphere. Main reservoirs are the atmosphere and the ocean. In a sedimentary cycle elements move from land to water to sediment. Main reservoirs are the soil and sedimentary rocks.

10 What sustains life on Earth?

11 Secrets to Survival An ecosystem survives by a combination of energy flow and matter recycling

12 Matter cycling in ecosystems Nutrient Cycles: Global Recycling Global Cycles recycle nutrients through the earth’s air, land, water, and living organisms. Nutrients are the elements and compounds that organisms need to live, grow, and reproduce. Biogeochemical cycles move these substances through air, water, soil, rock and living organisms.


14 What Is Carbon? An element The basis of life of earth Found in rocks, oceans, atmosphere

15 Carbon Cycle The same carbon atoms are used repeatedly on earth. They cycle between the earth and the atmosphere.

16 Plants Use Carbon Dioxide Plants pull carbon dioxide from the atmosphere and use it to make food –— photosynthesis. The carbon becomes part of the plant (stored food).

17 Animals Eat Plants When organisms eat plants, they take in the carbon and some of it becomes part of their own bodies.

18 Plants and Animal Die When plants and animals die, most of their bodies are decomposed and carbon atoms are returned to the atmosphere. Some are not decomposed fully and end up in deposits underground (oil, coal, etc.).

19 Carbon Slowly Returns to Atmosphere Carbon in rocks and underground deposits is released very slowly into the atmosphere. This process takes many years.

20 Carbon Cycle Diagram Carbon in Atmosphere Plants use carbon to make food Animals eat plants and take in carbon Plants and animals die Decomposers break down dead things, releasing carbon to atmosphere and soil Bodies not decomposed — after many years, become part of oil or coal deposits Fossil fuels are burned; carbon is returned to atmosphere Carbon slowly released from these substances returns to atmosphere

21 Carbon in Oceans Additional carbon is stored in the ocean. Many animals pull carbon from water to use in shells, etc. Animals die and carbon substances are deposited at the bottom of the ocean. Oceans contain earth’s largest store of carbon.

22 The Carbon Cycle

23 Human Impact Fossil fuels release carbon stores very slowly Burning anything releases more carbon into atmosphere — especially fossil fuels Increased carbon dioxide in atmosphere increases global warming Fewer plants mean less CO 2 removed from atmosphere


25 What We Need to Do Burn less, especially fossil fuels Promote plant life, especially trees

26 Oxygen Cycle

27 Nitrogen Cycle

28 Effects of Increased Nitrogen 1.Loss of soil nutrients (calcium, potassium) 2.Acidification of rivers and lakes (fertilizers and combustion of coal). 3.Increases nitrogen oxides in the atmosphere (greenhouse gas—global warming). (greenhouse gas—global warming). (reduce ozone—increasing UV penetration).

29 Effects of Increased Nitrogen 4. Aids in spreading weeds into nitrogen poor areas (+Eutrophication of lakes, ponds, streams). 5.Increasing nitrogen increases carbon fixation (linked to carbon cycle). 6.Increasing acidification increases weathering (increases rate of phosphorous cycle).


31 Phosphorus Cycle



34 Biogeochemical Cycle = Recycling All the chemicals, nutrients, or elements — such as carbon, nitrogen, oxygen, phosphorus — used in ecosystems by living organisms operate on a closed system

35 Conclusions In contrast to energy, which moves in one direction through the ecosystem, materials are continually recycled from the abiotic environment to organisms, and back to the abiotic environment. Changes in one of the biogeochemical cycles usually influences the other biogeochemical cycles.

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