Material Cycling in Ecosystems

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Material Cycling in Ecosystems

• 1.7

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• What role do decomposers play in an ecosystem?
• What nutrients are important to ecosystems?
• Materials in an ecosystem are used over and over
  again-4 Cycles- Carbon, Nitrogen, Minerals and
  Water

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Carbon Cycle

• Why is carbon important to ecosystems?
• All living things are composed mainly of carbon
• Cycle Producers take in CO2 during
  photosynthesis, consumers eat producers. When
  consumers break down their food using cellular
  respiration Carbon is released back into the
  atmosphere

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Human Effects on C-Cycle

• What are fossil fuels?
• Coal, oil, natural gas- comes from dead organisms
  from millions of years ago
• Burning fossil fuels- add carbon dioxide to the
  atmosphere- contributing to global warming

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Nitrogen Cycle

• All organisms need nitrogen to build proteins
• Nitrogen (N) makes up 78 of the atmosphere
• The only organisms that can use nitrogen directly
  are nitrogen fixing bacteria
• they take N from the atmosphere and transform, or
  fix it into a form that plants can use
• These bacteria live in the roots of some plants-
  use sugars from the plant for energy and produce
  N in the form of ammonia that the plant can use
• Other plants get N from the soil
• How do consumers get nitrogen?

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Nitrogen fixing bacteria have a mutualistic
relationship with plants. The bacteria live w/in
the nodules on the roots of some plants-they use
sugar from the plant for energy and in return
produce a form a nitrogen the plants can use to
survive
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Human Impact on Nitrogen cycle

• Farming has a large impact on the Nitrogen cycle
• Farmers add Nitrogen rich fertilizers to crops to
  help them grow, this puts more nitrogen into the
  ecosystem
• Burning fossil fuels also contribute to more
  Nitrogen in the atmosphere and can lead to acid
  rain

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Hydrologic (water) Cycle

• The hydrologic cycle describes the movement and
  storage of water on Earth
• Process that moves water from one place to
  another between the atmosphere and Earth
• Suns heat evaporates water from the Earths
  surface, as water vapor cools and condenses, it
  forms droplets in the clouds. When clouds meet
  cold air, water returns to the Earth as
  precipitation-rain, sleet, snow
• Where does the precipitation go?

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Water Cycle contd

• Precipitation falls into oceans, lakes, rivers
  some is absorbed by plants and soil
• Some gets trapped as groundwater-underground
  water that may rise to the surface again or be
  pumped up (wells)
• Water is also used by plants, taken up through
  their roots
• Water the plants dont use is released back into
  the atmosphere as water vapor- this process is
  called transpiration

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Human Impact on Water Cycle

• Discuss with group
• What are some human actions that affect the water
  cycle?