Nutrient Cycling and Retention

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Chapter 19

• Nutrient Cycling and Retention

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Definitions

• Nutrients elements required for the development,
  maintenance, and reproduction of organisms (N, P,
  K, etc.)
• Nutrient Cycling the use, transformations,
  movement, and reuse of nutrients in ecosystems

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Phosphorus
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Nitrogen
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Carbon
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Decomposition Moisture
Moisture enhances decomposition of organic
material
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Decomposition Nutrient Content
The presence of nitrogen speeds decomposition
while the presence of lignin slows
decomposition Species differ in their
concentrations of nitrogen and lignin
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Decomposition Climate
Long, warm growing seasons enhance rates of
decomposition
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Nutrient Cycling Streams
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Nutrient Cycling Grazers
The presence of grazers can speed rates of
nutrient cycling
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Nutrient Cycling Plant Species
Species rich in nitrogen can increase rates of
nutrient cycling
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Nutrient Cycling Disturbance
Disturbance can lead to immediate losses of
nutrients from ecosystems
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Nutrient Cycling Flooding
Flooding can lead to the time periods with the
greatest loss of nutrients from the ecosystem
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Nutrient Cycling Seasons
Seasonal patterns are related to peaks of
nutrient input and loss
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Nutrient Cycling The Vernal Dam

• Muller and Bormann Erythronium americanum takes
  up N in spring in amounts equal to that lost in
  the stream
• Zak and others soil microbes take up a lot more
• Tessier hmmmm..

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Mean decrease of 0.43 g N/m2
Mean increase of 3.07 g N/m2
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Nutrient Cycling Humans
Human activities greatly modify rates of nutrient
cycling and increase the loss of nutrients from
ecosystems
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Summary

• Nutrient Cycles
• Decomposition is affected by temperature,
  moisture, and chemical composition of organic
  matter
• Plants and animals modify nutrient cycling
• Disturbance increases the loss of nutrients
• Humans