Cycles of Matter MATTER CYCLES Each of the

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.

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

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.

• 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.

The Water Cycle • Water moves between the ocean, atmosphere, and land. • Let’s review some of the terms of that cycle!

• 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.

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

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

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

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.

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

Carbon Cycle • Carbon is a key ingredient of living tissue. • Biological processes, such as photosynthesis, respiration, and decomposition, take up and release carbon and oxygen. CO 2 in Atmosphere Photosynthesis feeding Respiration Decomposition • Geochemical processes, such as erosion and volcanic activity, release carbon dioxide to the atmosphere and oceans. Volcanic activity Human activity Erosion CO 2 in Ocean Respiration Uplift Deposition Photosynthesis Fossil fuel feeding Deposition Carbonate Rocks

• 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. Carbon Cycle CO 2 in Atmosphere Photosynthesis feeding Respiration Decomposition • Human activities, such as mining, cutting and burning forests, and burning fossil fuels, release carbon dioxide into the atmosphere. Volcanic activity Human activity Erosion CO 2 in Ocean Respiration Uplift Deposition Photosynthesis Fossil fuel feeding Deposition Carbonate Rocks

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.

• 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.

• 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.

Nitrogen Cycle N 2 in Atmosphere Synthetic fertilizer manufacturer Uptake by producers Bacterial nitrogen fixation Decomposition Reuse by consumers Decomposition excretion NH 3 Atmospheric nitrogen fixation Uptake by producers NO 3 and NO 2 Decomposition excretion Reuse by consumers

• 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 cycles between organisms and the soil. Plants bind the phosphates into organic compounds. Phosphorus Cycle Organisms Land Ocean Sediments

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.

• When an aquatic Nutrient 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. Limitation

Nutrient Cycles CO 2 in Atmosphere Photosynthesis feeding Volcanic activity Respiration Decomposition Human activity Erosion CO 2 in Ocean Respiration Uplift Deposition Photosynthesis Fossil fuel feeding Deposition Carbonate Rocks

– Transpiration is part of the • • water cycle. carbon cycle. nitrogen cycle. phosphorus cycle.

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

– 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.

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

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