role+of+the+carbon+and+nitrogen+cycles+in+maintaining+life+on+earth


 * //Role of the carbon and nitrogen cycles in maintaining life on earth// **


 * Videos**

Hydrologic and carbon cycles || media type="custom" key="24192138" Nitrogen and phosphorus cycles || media type="custom" key="24192854" Keeping up with carbon ||
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 * Common misconceptions:**
 * The atmosphere is big and carbon dioxide makes up a small % of the total gases. We are not adding enough carbon dioxide to make a difference.
 * The carbon cycle and water cycle are linked. Water carries carbon around the cycle.
 * Oxygen is needed by animals, whereas carbon dioxide is needed by plants.
 * Plants gain their mass from water and nutrients through roots.
 * The ocean has an almost infinite capacity to absorb CO2 and carbon, so the ocean reservoir can reduce any increase in CO2 concentration.
 * Since nitrogen is a nutrient, more is better.
 * Nitrogen gas is useless.
 * The nitrogen cycle is used to provide energy for the carbon cycle.
 * Nitrogen is released into the soil from the legume roots.


 * Interesting facts:**
 * Most gases in the atmosphere do not trap heat. Greenhouse gases including carbon dioxide do trap heat. Even though they may make up a relatively small percentage of the atmosphere, the way in which greenhouse gases trap heat adds up to having a large effect.
 * The cycling of each type of matter (nitrogen, phosphorous, carbon, water) are independent, though they may affect each other. Carbon moves between the atmosphere, the earth, and water due to factors including air pressure, photosynthesis by plants, respiration by plants and animals, and burning of biomass and fossil fuels. In contrast to the water cycle, the carbon cycle is not directly driven by the sun.
 * Plants respire like other organisms, however their rate of photosynthesis is higher than respiration so they have a net absorption or carbon dioxide. Plants gain their mass from photosynthesis.
 * Ocean acidification is occurring as a result of climate change, because too much carbon dioxide is being absorbed and getting converted in carbonic acid. The increase in temperature of the oceans because of human induced climate change makes the oceans less efficient at absorbing carbon dioxide as well.
 * Too much nitrogen (in the form of fertiliser) causes algal blooms which results in death of aquatic organisms in water ways.
 * Nitrogen gas is the source of nitrogen we use.
 * The primary pathways for nitrogen transfer from the legume to the soil are through grazing livestock and decomposition of dead legume plant material. When legume forage is consumed by grazing livestock, from 80 to 90% of the nitrogen in that forage passes through the animal and is excreted in the urine and feces. Unfortunately about 50% of the nitrogen in the urine is lost through volatilisation.


 * Resources:**
 * Biogeochemistry Workshop - the Nitrogen cycle from Cornell University Earth and Atmospheric Sciences.
 * Carbon Cycle Roleplay from California Academy of Sciences.
 * The Nitrogen Cycle from PBS LearningMedia.