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: – Ecosphere- Tissues of plants, animals, fungi, bacteria, etc. – Lithosphere- top soil – Atmosphere – Hydrosphere The Carbon Cycle

Fluxes: Sinks: - Photosynthesis - Fossil Fuels - Respiration (coal, oil, - Burning fossil fuels natural gas) - Burning trees - Rock- limestone - 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 in needed to make many compounds found in the body – DNA – Protein – Enzymes The Nitrogen Cycle

• Reservoirs/Sink s: – Atmosphere (78% N2 gas, but we can’t use it!) – Ecosphere (tissues of living things) The Nitrogen Cycle

• Fluxes • Our Impact: – Bacteria perform The Haber- many processes in Bosch Process

the nitrogen cycle removes N2 (nitrogen fixation, from the ammonification, atmosphere denitrification, and use it to decomposition). make fertilizer. – Lightning – Consumers 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 • Human Impact: – Run-off 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. – Bacteria populations increase and feed off of the dead algae and use up all the oxygen in the water. – Low oxygen levels cause other aquatic organisms to die to leave the area.