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Energy Transfer

The Role Of The Microbial Food Web

Much of the food web's energy is transferred to the often overlooked microbial, or decomposer, trophic level. Decomposers use excreted wastes and other dead biomass as a food source. Unlike the main, grazing food web, organisms of the microbial trophic level are extremely efficient feeders. Various species can rework the same food particle, extracting more of the stored energy each time. Some waste products of the microbial trophic level re-enter the grazing part of the food web and are used as growth materials for primary producers. This occurs, for example, when earthworms are eaten by birds.

See also Ecological pyramids; Energy budgets.

Resources

Books

Bradbury, I. The Biosphere. New York: Belhaven Press, Pinter Publishers, 1991.

Incropera, Frank P., and David P. DeWitt. Fundamentals of Heat and Mass Transfer. 5th ed. New York: John Wiley & Sons, 2001.

Miller, G. T., Jr. Environmental Science: Sustaining the Earth. 3rd ed. Belmont, CA: Wadsworth Publishing Company, 1991.

Stiling, P. D. "Energy Flow in Ecosystems." In Introductory Ecology. Englewood Cliffs, NJ: Prentice-Hall, 1992.

Periodicals

Begon, M., J. L. Harper, and C. R. Townsend. "The Flux of Energy Through Communities." In Ecology: Individuals, Populations and Communities. 2nd ed. Boston: Blackwell Scientific Publications, 1990.


Jennifer LeBlanc

KEY TERMS

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Biomass

—Total weight, volume, or energy equivalent of all living organisms within a given area.

Ecological efficiency

—Energy changes from one trophic level to the next.

First law of thermodynamics

—Energy can be transformed but it cannot be created nor can it be destroyed.

Primary consumer

—An organism that eats primary producers.

Primary producer

—An organism that photosynthesizes.

Second law of thermodynamics

—When energy is transformed, some of the original energy is degraded into less useful forms of energy.

Additional topics

Science EncyclopediaScience & Philosophy: Electrophoresis (cataphoresis) to EphemeralEnergy Transfer - History Of Energy Transfer Research, The Laws Of Thermodynamics And Energy Transfer In Food Webs, Components Of The Food Web