1. Aim: Cycling of Materials
Notepack 10
How Ecosystems Work
Aim: Cycling of Materials

2. Recycling Materials
Within any given ecosystem there is a limited amount of materials that organisms use in order to survive.
In some causes the limits placed on these materials will put a limit on the size of the populations that use the material.
Since organisms are constantly using these materials, the amount of these materials will decrease over time as the organisms use them.
For an ecosystem to be successful, there needs to be a way in which materials that are used can be replaced.
By recycling these materials, the ecosystem has an endless supply of essential materials.

3. The Carbon Cycle
The carbon cycle is the movement of carbon from the nonliving environment into living things and back
Carbon is the essential component of proteins, fats, and carbohydrates, which make up all organisms.
Proteins are important because it provides organisms with enzymes, hormones, and structure fibers, such as muscles.
Carbohydrates and fats provide organisms with useable energy, so they can perform metabolic activities.

4. The Carbon Cycle

5. The Carbon Cycle Carbon exists in air, water, and living organisms.
Producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis.
Consumers obtain carbon from the carbohydrates (glucose and starch) in the producers they eat.

6. The Carbon Cycle
During cellular respiration, some of the carbon is released back into the atmosphere as carbon dioxide.
Some carbon is stored in limestone, forming one of the largest “carbon sinks” on Earth.
Limestone is rock that is formed from the compression of tiny organisms, such as, coral, shellfish and zooplankton.
The carbon is released when the limestone is dissolved by water (rain). As the water breaks down the limestone, CO2 is released.

7. The Carbon Cycle
Carbon stored in the bodies of organisms as fat, oils, or other molecules, may be released into the soil or air when the organisms dies.
These molecules may form deposits of coal, oil, or natural gas, which are known as fossil fuels.
Fossil fuels store carbon left over from bodies of organisms that died millions of years ago.

8. How Humans Affect the Carbon Cycle
The release of carbon back into the environment is a natural process. The rate in which carbon returns to the environment is slow and steady, but organisms in an ecosystem are adapted to this rate of release.
However, humans are returning carbon back to the environment at a rapid rate.
This rapid release of carbon into the atmosphere, water and ground is having a tremendous impact on many ecosystems that are not adapted for such a rapid rate of carbon release.

9. How Humans Affect the Carbon Cycle
Humans are returning carbon back to the environment by:
- burning fossil fuels for energy – Burning fossil fuels release carbon into the atmosphere in the form of carbon dioxide. Fossil fuels include gas, coal and oil.
- Raising cattle – Cattle is an important food source for humans. They provide food, milk and leather. Cattle also produce lots of methane, which is released in the form of flatulent (farts).
-Deforestation – Deforestation is the removal of large areas of tree. Although not a big producer of carbon, (unless burnt down) the removal of trees reduces the environment from absorbing carbon from the air; therefore, keeping atmospheric carbon levels high.

10. How Humans Affect the Carbon Cycle
Increased levels of carbon dioxide may contribute to global warming.
Global warming is an increase in the temperature of the Earth.
Many ecosystems, such as, polar and mountain regions are greatly affected. Many of the organisms that live in these areas are adapted for cold weather climates. Because the temperatures are climbing at an abnormal rate, many of these organisms are having a hard time adapting, there by dying out
Coastal regions are also being affected because water that was once trapped in glacier ice is now being released as the ice melts. The now released water finds its way to the ocean causing an increase in sea level. The rise in sea level is causing flooding in coastal areas, effecting organisms that live there.

11. Norton the Nucleus Explains the Carbon Cycle
Carbon Cycle Explained

12. The Nitrogen Cycle
The nitrogen cycle is the process in which nitrogen circulates among the air, soil, water, plants, and animals in an ecosystem.
All organisms need nitrogen to build proteins, which are used to build new cells.
Nitrogen makes up 78 percent of the gases in the atmosphere.

13. The Nitrogen Cycle
Nitrogen is not a readily used molecules that organisms can use right away. It must be altered, or fixed, before organisms can use it.
Only a few species of bacteria can fix atmospheric nitrogen into chemical compounds that can be used by other organisms.
These bacteria are known as “nitrogen-fixing” bacteria.

14. The Nitrogen Cycle
Nitrogen-fixing bacteria are bacteria that convert atmospheric nitrogen into ammonia.
These bacteria live within the roots of plants called legumes, which include beans, peas, and clover.
The bacteria use sugar provided by the legumes to produce nitrogen-containing compounds such as nitrates.
Excess nitrogen fixed by the bacteria is released into the soil.

15. The Nitrogen Cycle

16. Decomposers and the Nitrogen Cycle
Nitrogen stored within the bodies of living things is returned to the nitrogen cycle once those organisms die.
Decomposers break down decaying plants and animals, as well as plant and animal wastes. Decomposers are made up of organisms such as fungi and bacteria. These organisms breakdown the dead organism into nitrogen compound molecules which seep into the soil.
After decomposers return nitrogen to the soil, bacteria transform a small amount of the nitrogen into nitrogen gas, which then returns to the atmosphere to complete the nitrogen cycle.

17. The Phosphorus Cycle
Phosphorus is an element that is part of many molecules that make up the cells of living organisms.
Plants get the phosphorus they need from soil and water, while animals get their phosphorus by eating plants or other animals that have eaten plants.
The phosphorus cycle is the cyclic movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment.
Phosphorous is important for many on the life processes of living things. In animals, phosphorous plays an important role in the skeletal and nervous systems.

18. The Phosphorus Cycle

19. The Phosphorus Cycle
Phosphorus may enter soil and water when rocks erode.
Small amounts of phosphorus dissolve as phosphate, which moves into the soil.
Plants absorb phosphates in the soil through their roots.
Some phosphorus washes off the land and ends up in the ocean.
Because many phosphate salts are not soluble in water, they sink to the bottom and accumulate as sediment.

20. Fertilizers and the Nitrogen and Phosphorus Cycles
Fertilizers, which people use to stimulate and maximize plant growth, contain both nitrogen and phosphorus.
Excessive amounts of fertilizer can enter terrestrial and aquatic ecosystems through runoff.
Excess nitrogen and phosphorus can cause rapid growth of algae, algal bloom.
Excess algae can deplete an aquatic ecosystem of important nutrients such as oxygen, on which fish and other aquatic organisms depend. This happens because the algae bloom blocks out the light from reaching the bottom plants. This stops photosynthesis from happening, there by killing the plants, followed by fish dying.

21. Acid Precipitation
When fuel is burned, large amounts of nitric oxide is release into the atmosphere.
In the air, nitric oxide can combine with oxygen and water vapor to form nitric acid.
Nitric acid lowers the pH of water vapor in the air.
Dissolved in rain or snow, the nitric acid falls as acid precipitation.

22. Acid Precipitation
Acid precipitation, most commonly acid rain can cause damage to pH sensitive ecosystems.
Plants and aquatic life are very sensitive to changes in pH.
Entire forest, as well as, ponds and streams, have been wiped out as the results of acid rain entering the ecosystem.
pH play an important role in an enzymes ability to perform chemical reactions. pH can cause enzymes and other proteins to change their shape, thereby making them ineffective in performing their job. This can lead to weaken or even death of an individual and/or a population.

23. Acid Rain Explained via YouTube!