World Atlas of Biodiversity

[Goswin_van_Eyck]

World Atlas of Biodiversity

The Biosphere
The biosphere is the thin and irregular envelope around and including the Earth's surface that contains all living organisms and the elements they exchange with the non-living environment.

Water makes up about two-thirds of an average living cell, and organic molecules based on hydrogen, carbon, nitrogen and oxygen make up the remaining one-third. These and other elements of living cells cycle repeatedly between the soil, sediment, air and water of the environment and the transient substance of living organisms.

The energy to maintain the structure of organisms enters the biosphere when sunlight is used by bacteria, algae and plants to produce organic molecules by photosynthesis, and all energy eventually leaves the biosphere again in the form of heat. Photosynthetic organisms themselves use a proportion of the organic material they synthesise; net primary production is the amount of energy-rich material left to sustain all other life on Earth.

Humans now appropriate a large proportion of global net primary production, and have caused planetary-scale perturbations in cycling of carbon, nitrogen, and other elements.
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