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Chemicals cycle in ecosystems. Concept 36.3. Basic pattern of chemical cycling. Three general steps Producers incorporate chemicals from the nonliving environment into organic compounds
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Chemicals cycle in ecosystems Concept 36.3
Basic pattern of chemical cycling • Three general steps • Producers incorporate chemicals from the nonliving environment into organic compounds • Consumers feed on the producers, incorporating some of the chemicals into their own bodies and releasing some back to the environment in waste products • As organisms die, decomposers break them down, further supplying the soil, water and air with chemicals in inorganic form. The producers gain a renewed supply of raw materials for building organic matter and the cycles continue.
The Nitrogen Cycle Form of N that producers can use • Nitrogen fixation • Process that converts the nitrogen gas to ammonia (NH3) • Nitrification • Process that converts ammonium to nitrates Ammonium NH4 Nitrates NO3
Nitrogen Fixation Nitrification
The Water Cycle • Transpiration • Evaporation from the plant’s leaves • Maple tree – could enter 200 liters back into the atmosphere!
Human Activities can alter ecosystems Concept 36.4
Carbon Cycle Impacts • Deforestation • Clearing of forest for agriculture, lumber and other uses • Adds 20% of CO2 added to atmosphere • 80% is from worldwide burning of fossil fuels
Greenhouse Effect • Process by which atmospheric gases trap heat close to Earth’s surface and prevent it from escaping into space • Global Warming • Overall rise in Earth’s average temperature
Nitrogen Cycle Impacts • Eutrophication • Rapid growth of algae in bodies of water, due to high levels of nitrogen and often phosphate • Acid Rain • Precipitation that carries acid back to Earth’s surface
Water Cycle Impacts • Deforestation • Drawing water from river or aquifers for household use or crop irrigation
Biological Magnification • Process by which pollutants become more concentrated in successive trophic levels of a food web
Ozone Shield • Ozone – O3 • Ozone layer – 17-25 kilometers above Earth • CFC’s – chlorofluorocarbons – banned in the 1980’s