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Nutrient Cycles 8th Grade Science A Generalized Cycle Materials often move between the regions of the earth- Atmosphere - Hydrosphere - Lithosphere - Ecosphere Cycle Terminology Reservoirs: areas where things are stored; things can move in and out Sinks: areas where materials are stored over long periods of time and in large quantities Fluxes: processes that move materials Carbon Importance: Life on Earth is carbon based- we are made of molecules that contain carbon. The Carbon Cycle Reservoirs: BiosphereTissues of plants, animals, fungi, bacteria, etc. Lithospheretop soil Atmosphere Hydrosphere The Carbon Cycle Sinks: - Fossil Fuels (coal, oil, natural gas) - Rock- limestone The Carbon Cycle Fluxes: - Photosynthesis - Respiration - Burning fossil fuels - Burning trees - Decomposition - Consumers The Carbon Cycle Human Impact: Humans have increased the amount of CO2 in the atmosphere from burning fossil fuels and wood. Nitrogen Importance: nitrogen is needed to make many compounds found in the body DNA Protein Enzymes The Nitrogen Cycle Reservoirs/Sinks: Atmosphere (78% N2 gas, but we can’t use it!) Ecosphere (tissues of living things) The Nitrogen Cycle Fluxes Bacteria perform many processes in the nitrogen cycle (nitrogen fixation, ammonification, denitrification, decomposition). Lightning Consumers The Nitrogen Cycle Our Impact: The Haber-Bosch Process removes N2 from the atmosphere and use it to make fertilizer. Potassium Importance: It is a mineral that is needed for muscle growth and for the normal function of cells and tissues. Potassium Cycle Reservoirs/sinks: Lithosphere: Mineral deposits and surface soil Ecosphere: Tissues of living things Potassium Cycle Fluxes: Weathering Uptake by plants Decomposition Consumers Phosphorus Importance: needed for many biological compounds such as DNA and for bone formation. Phosphorus Cycle Reservoirs/Sinks: Lithosphere: Earth’s crust and top soil Ecosphere: tissue of living things Phosphorus Cycle Fluxes: Decomposers Consumers Weathering of rocks Phosphorus Cycle Human Impact: Runoff from farms contains high levels of phosphorus which make their way into streams, rivers, etc. Too much of a good thing: Eutrophication: build-up of too many nutrients such as nitrogen or phosphorus in a body of water. Excess nutrients cause excessive algae growth. The algae blocks sunlight from reaching the bottom, causing other algae to die. The algae at the surface die and fall to the bottom. Feces from fish and zooplankton that feed off the algae fall to the bottom Bacteria populations increase and feed off of the dead algae and feces and use up all the oxygen in the water. Low oxygen levels cause other aquatic organisms to die or leave the area. Eutrophication Eutrophication