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Biosphere

Current Research

Most research investigating the biosphere is aimed at determining the effects that human activities are having on its environments and ecosystems. Pollution, fertilizer application, changes in land use, fuel consumption, and other human activities affect nutrient cycles and damage functional components of the biosphere, such as the ozone layer that protects organisms from intense exposure to solar ultraviolet radiation, and the greenhouse effect that moderates the surface temperature of the planet.


For example, fertilizer application increases the amounts of nitrogen, phosphorus, and other nutrients that organisms can use for growth. An excess nutrient availability can damage lakes through algal blooms and fish kills. Fuel consumption and land clearing increases the concentration of carbon dioxide in the atmosphere, and may cause global warming by intensifying the planet's greenhouse effect.

Recent interest in long-term, manned space operations has spawned research into the development of artificial biospheres. Extended missions in space require that nutrients are cycled in a volume no larger than a building. The Biosphere 2 project, which received a great deal of popular attention in the early 1990s, has provided insight into the difficulty of managing such small, artificial biospheres. Human civilization is also finding that it is difficult to sustainably manage the much larger biosphere of planet Earth.

See also Lithosphere.


Resources

Books

Allen, John. Biosphere 2: The Human Experiment. New York: Viking, 1991.

Bradbury, I. K. The Biosphere. London/New York: Bellhaven Press, 1991.

Hamblin, W.K., and E.H. Christiansen. Earth's Dynamic Systems. 9th ed. Upper Saddle River: Prentice Hall, 2001.

Levin, Simon A., ed. Encyclopedia of Biodiversity. San Diego, CA: Academic Press, 2000.

Odum, Eugene. Ecology and Our Endangered Life-Support Systems. 2nd ed. Sunderland, MA: Sinauer Associates, 1993.

Smil, V. Cycles of Life: Civilization and the Biosphere. W.H. Freeman and Co., 1997.

Tudge, Colin. Global Ecology. New York: Oxford University Press, 1991.

Periodicals

Clark, B. C. "Planetary Interchange of Bioactive Material: Probability Factors and Implications." Origins of Life and Evolution of the Biosphere no. 31 (2001): 185–197.

Huggett, R. J. "Ecosphere, Biosphere, Or Gaia? What To Call The Global Ecosystem." Global Ecology And Biogeography 8, no. 6 (1999): 425-432.

Salthe, S.N. "The Evolution of the Biosphere: Towards a New Mythology." World Futures. 30 (1990): 53-67.


Steven MacKenzie

KEY TERMS

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Decomposition

—The breakdown of the complex molecules composing dead organisms into simple nutrients that can be reutilized by living organisms.

Energy

—The ability to do work. Energy occurs in various forms. The most important ones in biospheric processes are solar (electromagnetic), kinetic, heat (or thermal), and chemical-bond energies.

Global warming

—Atmospheric warming caused by an increase in the concentration of greenhouse gases, which absorb infrared energy emitted by Earth's surface, thereby slowing its rate of cooling. Carbon dioxide and water vapor are particularly important in this respect.

Nutrient cycle

—The cycling of biologically important elements from one molecular form to another, and eventually back to the original form.

Nutrients

—The molecules organisms obtain from their environment and are used for growth, energy, and other metabolic processes.

Photosynthesis

—Enzymatic, sunlight-induced reaction between carbon dioxide and water, which produces oxygen and organic molecules. Plants, algae, and certain bacteria are photosynthetic organisms.

Respiration

—Enzymatic chemical reactions between organic molecules and oxygen, which result in the production of carbon dioxide, water, and energy.

Additional topics

Science EncyclopediaScience & Philosophy: Bilateral symmetry to Boolean algebraBiosphere - History, Requirements For Life, Evolution Of The Biosphere, Current Research