Biomass (ecology)
In ecology, biomass refers to the cumulation of living matter. 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
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. Humans comprise about 250 million tons ,
domesticated animals about 700 million , and
crops about 2 billion tons or 2.7% of the Earth's biomass.
Encyclopedia
In ecology,
biomass refers to the cumulation of living matter. 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
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. Humans comprise about 250 million tons ,
domesticated animals about 700 million , and
crops about 2 billion tons or 2.7% of the Earth's biomass.
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 have a much higher biomass than animals that
consume them . The level with the least biomass is the highest
predators in the food chain
Biomass is also related to net primary productivity . 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 and thus tend to increase biomass are the converse of these.
Biomass production
Biomass production for human use and consumption.
| BIOME ECOSYSTEM TYPE | Area | Mean Net Primary Production | World Primary Production | Mean biomass | World biomass | Minimum replacement rate |
|---|
| | | | | | | |
| Tropical rain forest | 17.0 | 2,200 | 37.40 | 45.00 | 765.00 | 20.45 |
| Tropical monsoon forest | 7.5 | 1,600 | 12.00 | 35.00 | 262.50 | 21.88 |
| Temperate evergreen forest | 5.0 | 1,320 | 6.60 | 35.00 | 175.00 | 26.52 |
| Temperate deciduous forest | 7.0 | 1,200 | 8.40 | 30.00 | 210.00 | 25.00 |
| Boreal forest | 12.0 | 800 | 9.60 | 20.00 | 240.00 | 25.00 |
| Mediterranean open forest | 2.8 | 750 | 2.10 | 18.00 | 50.40 | 24.00 |
| Woodland & shrubland | 5.7 | 700 | 3.99 | 6.00 | 34.20 | 8.57 |
| Savanna | 15.0 | 900 | 13.50 | 4.00 | 60.00 | 4.44 |
| Temperate grassland | 9.0 | 600 | 5.40 | 1.60 | 14.40 | 2.67 |
| Tundra and alpine | 8.0 | 140 | 1.12 | 0.60 | 4.80 | 4.29 |
| Desert & semidesert scrub | 18.0 | 90 | 1.62 | 0.70 | 12.60 | 7.78 |
| Extreme desert, rock, sand or ice sheets | 24.0 | 3 | 0.07 | 0.02 | 0.48 | 6.67 |
| Cultivated land | 14.0 | 650 | 9.10 | 1.00 | 14.00 | 1.54 |
| Swamp & marsh | 2.0 | 2,000 | 4.00 | 15.00 | 30.00 | 7.50 |
| Lake and stream | 2.0 | 250 | 0.50 | 0.02 | 0.04 | 0.08 |
| Total continental | 149.00 | 774.51 | 115.40 | 12.57 | 1,873.42 | 16.23 |
| Open Ocean | 332.00 | 125.00 | 41.50 | 0.003 | 1.00 | 0.02 |
| Upwelling zones | 0.40 | 500.00 | 0.20 | 0.020 | 0.01 | 0.04 |
| Continental shelf | 26.60 | 360.00 | 9.58 | 0.010 | 0.27 | 0.03 |
| Algal beds and reefs | 0.60 | 2,500.00 | 1.50 | 2.000 | 1.20 | 0.80 |
| Estuaries & mangroves | 1.40 | 1,500.00 | 2.10 | 1.000 | 1.40 | 0.67 |
| Total marine | 361.00 | 152.01 | 54.88 | 0.01 | 3.87 | 0.07 |
| Grand total | 510.00 | 926.52 | 170.28 | 12.58 | 1,877.29 | 11.02 |
Source: Whittaker R.H. & Likens G.E. "The Biosphere and Man" pp.305-328 in Leith H. & Whittaker R.H.
Primary Production of the Biosphere" Springer-Verlag Ecological Studies Vol 14
See also
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