Cycles of Matter

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.

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

3. Recycling in the Biosphere • 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!

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 itsnutrients. • 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 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 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 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 N2 in Atmosphere Synthetic fertilizer manufacturer Atmospheric nitrogen fixation Decomposition Uptake by producers Reuse by consumers Uptake by producers Reuse by consumers Decomposition excretion Decomposition excretion Bacterial nitrogen fixation NO3 and NO2 NH3

18. Phosphorus Cycle • 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. • 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 Photosynthesis Volcanic activity feeding Respiration Erosion Human activity Respiration Decomposition CO2 in Ocean Uplift 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.