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In ecology, 'biomass' refers to the cumulation of living matter.^[2] That is, it is the total living biological material in a given area or of a biological community or group. Biomass is measured by weight, or by dry weight, per given area (usually measured per square metre or square kilometre). This means that only 30% of the weight of any creature is counted, the rest being water.
The most successful animal, in terms of biomass, is the Antarctic krill, ''Euphausia superba'', with a biomass of probably over 500 million tons, roughly twice the total biomass of humans. The entire earth contains about 75 billion tons of biomass, or 0.00000000126% of the total mass of the Earth. Humans comprise about 250 million tons (0.33%) of the Earth's biomass, domesticated animals about 700 million (1.0%), and crops about 2 billion tons or 2.7% of the Earth's biomass. The total biomass of bacteria is estimated to equal that of plants ^[3].
Biomass may also be a measure of the dried organic mass of an ecosystem. As the trophic level increases, the biomass of each trophic level decreases. That is, producers (grass, trees, scrubs, etc.) have a much higher biomass than animals that consume them (deer, zebras, insects, etc.). The level with the least biomass is the highest predators in the food chain (foxes, eagles, etc.)
Biomass is also related to net primary productivity (NPP). Factors which limit NPP and thus mean biomass accumulates only slowly, include

★ Low rainfall

★ Low temperaures

★ Little available nutrients

★ Short growing season

★ Lack of supply of stock material
Factors which encourage NPP and thus tend to increase biomass are the converse of these.

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See also

References

External links

See also

★ Biota (ecology)

★ Ecological pyramid

★ Water mass

References

1. Fisheries Technical Paper 367: Krill Fisheries of the World, Nicol, S., Endo, Y., , , FAO, 1997,
2.
3. Whitman, Coleman, and Wiebe, Prokaryotes: The unseen majority, Proc. Natl. Acad. Sci. USA, Vol. 95, pp. 6578–6583, June 1998

External links

Counting bacteria