KEY CONCEPT Matter cycles in and out of an ecosystem.

1. KEY CONCEPT Matter cycles in and out of an ecosystem.

2. precipitation condensation transpiration evaporation surface runoff lake water storage in ocean groundwater seepage Water cycles through the environment. • The hydrologic, or water, cycle is the circular pathway of water on Earth. • Organisms all have bodies made mostly of water.

3. Elements essential for life also cycle through ecosystems. • A biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an ecosystem. • The main processes involved in the oxygen cycle are photosynthesis and respiration.

4. oxygen photosynthesis respiration carbon dioxide • Oxygen cycles indirectly through an ecosystem by the cycling of other nutrients. Fig. In the oxygen cycle, oxygen flows into the atmosphere as a byproduct of photosynthesis. Organisms take in this oxygen and release it as carbon dioxide through respiration.

5. carbon dioxide in air respiration combustion photosynthesis respiration photosynthesis decomposition of organisms carbon dioxide dissolved in water fossil fuels • The carbon cycle moves carbon from the atmosphere, through the food web, and returns to the atmosphere. • Carbon is emitted by the burning of fossil fuels. • Some carbon is stored for long periods of time in areas called carbon sinks. • Carbon is the building block of life. Fig. Photosynthesis and respiration account for much of the transformation and movement of carbon.

6. nitrogen in atmosphere animals plant nitrates nitrogen-fixing bacteria in roots decomposers nitrifying bacteria ammonification nitrites nitrogen-fixing bacteria in soil ammonium nitrifying bacteria denitrifying bacteria • Some bacteria convert gaseous nitrogen into ammonia through a process called nitrogen fixation. • Some nitrogen-fixing bacteria live innodules on theroots of legumes;others livefreely inthe soil. • The nitrogen cycle mostly takes place underground. Fig. Much of the nitrogen cycle occurs underground, where bacteria transform ammonium into nitrates, which are used by plants to make amino acids.

7. nitrogen in atmosphere animals plant nitrates nitrogen-fixing bacteria in roots decomposers nitrifying bacteria ammonification nitrites nitrogen-fixing bacteria in soil ammonium nitrifying bacteria denitrifying bacteria • Nitrifying bacteria change the ammonium into nitrate. • Nitrogen moves through the foodweb and returnsto the soil duringdecomposition. • Ammonia released into the soil is transformed into ammonium. Fig. Much of the nitrogen cycle occurs underground, where bacteria transform ammonium into nitrates, which are used by plants to make amino acids.

8. Eutrophication When excessive inorganic nutrients (like nitrogen or phosphorus) build up in a lake or other body of water algal blooms occur. This is usually caused by excessive use of fertilizers that run off from land into the water system. Once the algae and plants die off, decomposers deplete the water of oxygen while breaking down the dead plant and algae matter. Once oxygen levels drop too low, fish and other animals that live in the water suffocate and die. Fig. Red tide is a phenomenon caused by algal blooms (Wikipedia definition) during which algae become so numerous that they discolor coastal waters (hence the name "red tide"). The algal bloom may also deplete oxygen in the waters and/or release toxins that may cause illness in humans and other animals. Jun 14, 2015

9. rain geologic uplifting weathering of phosphate from rocks runoff plants animals phosphate in soil phosphate in solution leaching sedimentation forms new rocks decomposers • Phosphate is released by the weathering of rocks. • Phosphorus moves through the food web and returns to the soil during decomposition of organic matter. • The phosphorus cycle takes place at and below ground level. • Phosphorus leaches into groundwater from the soil and is locked in sediments. • Both mining and agriculture add phosphorus into the environment.