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17 Cards in this Set
- Front
- Back
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What is carbon?
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Basic constiuent of all organic compounds and is involved in the fixation of energy by photosynthesis (CO2).
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What is the source of all carbon in both living organisms and fossil deposits?
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Carbon Dioxide in the atmosphere and the waters of the Earth.
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What is meant by diurnal fluctuation of Carbon Dioxide?
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CO2 is down during the day as the plants withdraw the CO2 for photosynthesis, CO2 is up at night when photosynthesis ceases and plants respire CO2 into the atmosphere.
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What is Nitrogen?
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An essential constituent of protein, which is a building block of all living tissue.
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What are the two forms of nitrogen available to plants?
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Ammonium and Nitrate.
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What are the two ways nitrogen enters the ecosystem?
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Atmospheric Deposition and Nitrogen Fixation.
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How is nitrogen supplied via atmospheric deposition?
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By wetfall (rain, snow, or even cloud and fog droplets).
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How is nitrogen supplied via nitrogen fixation?
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High energy fixation (cosmic radiation, meteorite trails, and lightning) and Biological fixation (symbiotic bacteria lving in mutualistic association with plants).
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What is ammonification?
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NH4 occurs in the soil as a product of microbial decomposition or organic matter, wherein NH3 is released as a waste product of microbial activity.
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What is nitrification?
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Brings nitrogen to us via lightning which converts nitrates to nitrites.
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What are the main reservoirs of phosphorous?
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Rock and natural phosphate deposits.
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How is phosphorous released by rocks and minerals?
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Weathering, leaching, erosion, and mining for use as agricultural fertilizers.
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What nutrient has both sedimentary and gaseous phases?
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Sulfur.
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What are the sources of sulfur that enter the Earth's atmosphere?
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Combustion of fossil fuels, volcanic eruptions, exchange at the surface of the oceans, and gases released by decomposition.
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What is the sulfur cycle?
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Enters initially as hydrogen sulfide, which interacts with oxygen to form sulfur dioxide. Soluble in water, it is carried back to the surface via rainwater as weak sulfuric acid. In a soluble form it is taken up by plants starting with photosynthesis, turned into sulfur-bearing amino acids and transferred to the consumers.
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What is the major source of free oxygen that supports life?
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The atmosphere.
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What are the two significant sources of altmospheric oxygen?
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The breakup of water vapor through a process driven by sunlight and photosynthesis.
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