1. Cycles of Matter MATTER CYCLES
Each of the elements that is vital for life exists on Earth in a closed loop of cyclical changes. From a systems point of view, Earth is essentially a closed system with respect to matter.
ENERGY FLOWS
The functioning of our planet relies on a constant input of energy from the sun. This energy leaves Earth in the form of heat flowing to outer space. From a systems point of view, Earth is an open system with respect to energy.
LIFE WEBS
A vast and intricate network of relationships connects all Earth's organisms with each other and with the cycles of matter and the flows of energy. From a systems point of view, Earth is a networked system with respect to life.
Photo Credit: ©Bruce Coleman, LTD/Natural Selection

2. Recycling in the Biosphere
Energy and matter move through the biosphere very differently.

3. Recycling in the Biosphere
Energy and matter move through the biosphere very differently.
Unlike the one-way flow of energy, matter is recycled within and between ecosystems.

4. Elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another through biogeochemical cycles.
Matter can cycle because biological systems do not use up matter, they transform it.
Matter is assembled into living tissue or passed out of the body as waste products.

5. The Water Cycle Water moves between the ocean, atmosphere, and land.
Let’s review some of the terms of that cycle!
This diagram shows the main processes involved in the water cycle. Scientists estimate that it can take a single water molecule as long as 4000 years to complete one cycle.

6. The process by which water changes from a liquid form in the ocean or other bodies of water into an atmospheric gas is called evaporation.

7. Water can also enter the atmosphere by evaporating from the leaves of plants in the process of transpiration.

8. Water vapor condenses into tiny droplets that form clouds (condensation), and then returns to Earth’s surface as precipitation (rain).

9. Water enters streams or seeps into soil where it enters plants through their roots to start the cycle all over again!

10. Nutrient Cycles Nutrient Cycles
All the chemical substances that an organism needs to sustain life are its nutrients.
Every living organism needs nutrients to build tissues and carry out essential life functions.
Similar to water, nutrients are passed between organisms and the environment through biogeochemical cycles.

11. Nutrient Cycles
Primary producers, such as plants, usually obtain nutrients in simple inorganic forms from their environment.
Consumers obtain nutrients by eating other organisms.

12. Carbon Cycle CO2 in Atmosphere CO2 in Ocean
Carbon is a key ingredient of living tissue.
Biological processes, such as photosynthesis, respiration, and decomposition, take up and release carbon and oxygen.
Geochemical processes, such as erosion and volcanic activity, release carbon dioxide to the atmosphere and oceans.
Carbon Cycle
CO2 in Atmosphere
Photosynthesis
Volcanic activity
feeding
Respiration
Erosion
Human activity
Respiration
Decomposition
CO2 in Ocean
Uplift
Carbon is found in several large reservoirs in the biosphere. In the atmosphere, it is found as carbon dioxide gas; in the oceans as dissolved carbon dioxide; on land in organisms, rocks, and soil; and underground as coal, petroleum, and calcium carbonate rock. 
Deposition
Photosynthesis
feeding
Fossil fuel
Deposition
Carbonate Rocks

13. Biogeochemical processes, such as the burial and decomposition of dead organisms and their conversion under pressure into coal and petroleum (fossil fuels), store carbon underground.
Human activities, such as mining, cutting and burning forests, and burning fossil fuels, release carbon dioxide into the atmosphere.
Carbon Cycle
CO2 in Atmosphere
Photosynthesis
Volcanic activity
feeding
Respiration
Erosion
Human activity
Respiration
Decomposition
CO2 in Ocean
Uplift
Carbon is found in several large reservoirs in the biosphere. In the atmosphere, it is found as carbon dioxide gas; in the oceans as dissolved carbon dioxide; on land in organisms, rocks, and soil; and underground as coal, petroleum, and calcium carbonate rock. 
Deposition
Photosynthesis
feeding
Fossil fuel
Deposition
Carbonate Rocks

14. Nitrogen Cycles The Nitrogen Cycle
All organisms require nitrogen to make proteins.
Although nitrogen gas is the most abundant form of nitrogen on Earth, only certain types of bacteria can use this form directly.
Such bacteria live in the soil and on the roots of plants called legumes. They convert nitrogen gas into ammonia in a process known as nitrogen fixation.

15. Other bacteria in the soil convert ammonia into nitrates and nitrites.
Once these products are available, producers can use them to make proteins.
Consumers then eat the producers and reuse the nitrogen to make their own proteins.

16. When organisms die, decomposers return nitrogen to the soil as ammonia.
The ammonia may be taken up again by producers.
Other soil bacteria convert nitrates into nitrogen gas in a process called denitrification.
This process releases nitrogen into the atmosphere once again.

17. Nitrogen Cycle NH3 N2 in Atmosphere NO3 and NO2
Synthetic fertilizer manufacturer
Atmospheric nitrogen fixation
Decomposition
Uptake by producers
Reuse by consumers
Uptake by producers
Reuse by consumers
The atmosphere is the main reservoir of nitrogen in the biosphere. Nitrogen also cycles through the soil and through the tissues of living organisms. 
Decomposition excretion
Decomposition excretion
Bacterial nitrogen fixation
NO3 and NO2
NH3

18. Phosphorus Cycle Organisms Land Ocean Sediments
Phosphorus is essential to organisms because it helps forms important molecules like DNA and RNA.
Most phosphorus exists in the form of inorganic phosphate. Inorganic phosphate is released into the soil and water as sediments wear down.
Organic phosphate moves through the food web and to the rest of the ecosystem.
Phosphate, eventually enters the ocean, where it is used by marine organisms.
Some phosphate stays on land and cycles between organisms and the soil. Plants bind the phosphates into organic compounds.
Phosphorus Cycle
Organisms
Phosphorus in the biosphere cycles among the land, ocean sediments, and living organisms.
Land
Ocean
Sediments

19. Nutrient Limitation
The primary productivity of an ecosystem is the rate at which organic matter is created by producers.
One factor that controls the primary productivity of an ecosystem is the amount of available nutrients.
If a nutrient is in short supply, it will limit an organism's growth.
When an ecosystem is limited by a single nutrient that is scarce or cycles very slowly, this substance is called a limiting nutrient.

20. Nutrient Limitation
When an aquatic ecosystem receives a large input of a limiting nutrient—such as runoff from heavily fertilized fields—the result is often an immediate increase in the amount of algae and other producers.
This result is called an algal bloom.
Algal blooms can disrupt the equilibrium of an ecosystem.

21. Nutrient Cycles CO2 in Atmosphere CO2 in Ocean Carbonate Rocks
Photosynthesis
Volcanic activity
feeding
Respiration
Erosion
Human activity
Respiration
Decomposition
CO2 in Ocean
Uplift
Carbon is found in several large reservoirs in the biosphere. In the atmosphere, it is found as carbon dioxide gas; in the oceans as dissolved carbon dioxide; on land in organisms, rocks, and soil; and underground as coal, petroleum, and calcium carbonate rock. 
Deposition
Photosynthesis
feeding
Fossil fuel
Deposition
Carbonate Rocks

22. Transpiration is part of the
water cycle.
carbon cycle.
nitrogen cycle.
phosphorus cycle.

23. Carbon is found in the atmosphere in the form of
carbohydrates.
carbon dioxide.
calcium carbonate.
ammonia.

24. Biologists describe nutrients as moving through cycles because the substances
start as simple organic forms that plants need.
provide “building blocks” and energy that organisms need.
are passed between organisms and the environment and then back to organisms.
are needed by organisms to carry out life processes.

25. The only organisms that can convert nitrogen in the atmosphere into a form useful to living things are nitrogen-fixing
plants.
bacteria.
detritivores.
animals.

26. When an aquatic ecosystem receives a large input of a limiting nutrient, the result is
runoff.
algal death.
algal bloom.
less primary productivity.