Biomass (ecology)

The biomass is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms, plants or animals.[4] The mass can be expressed as the average mass per unit area, or as the total mass in the community.

How biomass is measured depends on why it is being measured. Sometimes, the biomass is regarded as the natural mass of organisms in situ, just as they are. For example, in a salmon fishery, the salmon biomass might be regarded as the total wet weight the salmon would have if they were taken out of the water. In other contexts, biomass can be measured in terms of the dried organic mass, so perhaps only 30% of the actual weight might count, the rest being water. For other purposes, only biological tissues count, and teeth, bones and shells are excluded. In some applications, biomass is measured as the mass of organically bound carbon (C) that is present.

The total live biomass on Earth is about 550–560 billion tonnes C,[1][5] and the total annual primary production of biomass is just over 100 billion tonnes C/yr.[6] The total live biomass of bacteria may be as much as that of plants and animals[7] or may be much less.[1][8][9][10][11] The total number of DNA base pairs on Earth, as a possible approximation of global biodiversity, is estimated at (5.3±3.6)×1037, and weighs 50 billion tonnes.[12][13] In comparison, the total mass of the biosphere has been estimated to be as much as 4×1012 tonnes of carbon.[14]

7 - Itahuania - Août 2008
Apart from bacteria, the total global live biomass has been estimated as 550 or 560 billion tonnes C,[1] most of which is found in forests.[2]
Klamath river estuary
Shallow aquatic environments, such as wetlands, estuaries and coral reefs, can be as productive as forests, generating similar amounts of new biomass each year on a given area.[3]

Ecological pyramids

Ecological pyramid
An ecological pyramid.

An ecological pyramid is a graphical representation that shows, for a given ecosystem, the relationship between biomass or biological productivity and trophic levels.

  • A biomass pyramid shows the amount of biomass at each trophic level.
  • A productivity pyramid shows the production or turn-over in biomass at each trophic level.

An ecological pyramid provides a snapshot in time of an ecological community.

The bottom of the pyramid represents the primary producers (autotrophs). The primary producers take energy from the environment in the form of sunlight or inorganic chemicals and use it to create energy-rich molecules such as carbohydrates. This mechanism is called primary production. The pyramid then proceeds through the various trophic levels to the apex predators at the top.

When energy is transferred from one trophic level to the next, typically only ten percent is used to build new biomass. The remaining ninety percent goes to metabolic processes or is dissipated as heat. This energy loss means that productivity pyramids are never inverted, and generally limits food chains to about six levels. However, in oceans, biomass pyramids can be wholly or partially inverted, with more biomass at higher levels.

Terrestrial biomass

Terrestrial biomass generally decreases markedly at each higher trophic level (plants, herbivores, carnivores). Examples of terrestrial producers are grasses, trees and shrubs. These have a much higher biomass than the animals that consume them, such as deer, zebras and insects. The level with the least biomass are the highest predators in the food chain, such as foxes and eagles.

In a temperate grassland, grasses and other plants are the primary producers at the bottom of the pyramid. Then come the primary consumers, such as grasshoppers, voles and bison, followed by the secondary consumers, shrews, hawks and small cats. Finally the tertiary consumers, large cats and wolves. The biomass pyramid decreases markedly at each higher level.

Ocean biomass

Ocean or marine biomass, in a reversal of terrestrial biomass, can increase at higher trophic levels. In the ocean, the food chain typically starts with phytoplankton, and follows the course:

Phytoplankton → zooplankton → predatory zooplankton → filter feeders → predatory fish

Phytoplankton are the main primary producers at the bottom of the marine food chain. Phytoplankton use photosynthesis to convert inorganic carbon into protoplasm. They are then consumed by microscopic animals called zooplankton.

Zooplankton comprise the second level in the food chain, and includes small crustaceans, such as copepods and krill, and the larva of fish, squid, lobsters and crabs.

In turn, small zooplankton are consumed by both larger predatory zooplankters, such as krill, and by forage fish, which are small, schooling, filter-feeding fish. This makes up the third level in the food chain.

Arctic food web
An ocean food web showing a network of food chains

The fourth trophic level consists of predatory fish, marine mammals and seabirds that consume forage fish. Examples are swordfish, seals and gannets.

Apex predators, such as orcas, which can consume seals, and shortfin mako sharks, which can consume swordfish, make up the fifth trophic level. Baleen whales can consume zooplankton and krill directly, leading to a food chain with only three or four trophic levels.

Marine environments can have inverted biomass pyramids. In particular, the biomass of consumers (copepods, krill, shrimp, forage fish) is larger than the biomass of primary producers. This happens because the ocean's primary producers are tiny phytoplankton that grow and reproduce rapidly, so a small mass can have a fast rate of primary production. In contrast, terrestrial primary producers grow and reproduce slowly.

There is an exception with cyanobacteria. Marine cyanobacteria are the smallest known photosynthetic organisms; the smallest of all, Prochlorococcus, is just 0.5 to 0.8 micrometres across.[15] Prochlorococcus is possibly the most plentiful species on Earth: a single millilitre of surface seawater may contain 100,000 cells or more. Worldwide, there are estimated to be several octillion (~1027) individuals.[16] Prochlorococcus is ubiquitous between 40°N and 40°S and dominates in the oligotrophic (nutrient poor) regions of the oceans.[17] The bacterium accounts for an estimated 20% of the oxygen in the Earth's atmosphere, and forms part of the base of the ocean food chain.[18]

Bacterial biomass

There are typically 50 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. In a much-cited study from 1998,[7] the world bacterial biomass had been mistakenly calculated to be 350 to 550 billions of tonnes of carbon, equal to between 60% and 100% of the carbon in plants. More recent studies of seafloor microbes cast considerable doubt on that; one study in 2012[8] reduced the calculated microbial biomass on the seafloor from the original 303 billions of tonnes of C to just 4.1 billions of tonnes of C, reducing the global biomass of prokaryotes to 50 to 250 billions of tonnes of C. Further, if the average per-cell biomass of prokaryotes is reduced from 86 to 14 femtograms C,[8] then the global biomass of prokaryotes was reduced to 13 to 44.5 billions of tonnes of C, equal to between 2.4% and 8.1% of the carbon in plants.

As of 2018, there continues to be some controversy over what the global bacterial biomass is. A census published by the PNAS in May 2018 gives for bacterial biomass ~70 billions of tonnes of carbon, equal to 15% of the whole biomass.[1] A census by the Deep Carbon Observatory project published in December 2018 gives a smaller figure of up to 23 billion tonnes of carbon.[9][10][11]

Geographic location Number of cells (× 1029) Billions of tonnes of carbon
Ocean floor
2.9[8] to 50[19]
4.1[8] to 303[7]
Open ocean
1.7[7][8] to 10[7]
Terrestrial soil
3.7[7][8] to 22[7]
Subsurface terrestrial
2.5 to 25[7]
3.5[7][8] to 215[7]

Global biomass

Estimates for the global biomass of species and higher level groups are not always consistent across the literature. The total global biomass has been estimated at about 550 billion tonnes C.[5][20] Most of this biomass is found on land, with only 5 to 10 billion tonnes C found in the oceans.[5] On land, there is about 1,000 times more plant biomass (phytomass) than animal biomass (zoomass). About 18% of this plant biomass is eaten by the land animals.[21] However, in the ocean, the animal biomass is nearly 30 times larger than the plant biomass.[22] Most ocean plant biomass is eaten by the ocean animals.[21]

name number of species date of estimate individual count mean living mass of individual percent biomass (dried) total number of carbon atoms global dry biomass in million tonnes global wet (fresh) biomass in million tonnes
7.0 billion
50 kg
(incl children)
4.63 billion
62 kg
(excl. children)[25]
1.3 billion[26]
400 kg
1.75 billion[27]
60 kg
24 billion
2 kg
107–108 billion[29]
3×10−6 kg
(0.003 grams)
1.3×106 billion [30]
3 g
30% [31]
0.486 g
10−6–10−9 kg
1×1031 cells[1]
23,000[9] – 70,000[1]

Humans comprise about 100 million tonnes of the Earth's dry biomass,[39] domesticated animals about 700 million tonnes, earthworms over 1,100 million tonnes,[30] and annual cereal crops about 2.3 billion tonnes.[40]

The most successful animal species, in terms of biomass, may well be Antarctic krill, Euphausia superba, with a fresh biomass approaching 500 million tonnes,[36][41][42] although domestic cattle may also reach these immense figures. However, as a group, the small aquatic crustaceans called copepods may form the largest animal biomass on earth.[43] A 2009 paper in Science estimates, for the first time, the total world fish biomass as somewhere between 0.8 and 2.0 billion tonnes.[44][45] It has been estimated that about 1% of the global biomass is due to phytoplankton,[46] and 25% is due to fungi.[47][48]

Cytisus scoparius2

Grasses, trees and shrubs have a much higher biomass than the animals that consume them

Bluegreen algae

The total biomass of bacteria may equal that of plants.[7]


Copepods may form the largest biomass of any animal species group.[43]

Antarctic krill (Euphausia superba)

Antarctic krill form one of the largest biomasses of any individual animal species.[41]

Fungus, Minnowburn - - 1008404

It has been claimed that fungi make up 25% of the global biomass

Global rate of production

Seawifs global biosphere
Globally, terrestrial and oceanic habitats produce a similar amount of new biomass each year (56.4 billion tonnes C terrestrial and 48.5 billion tonnes C oceanic).

Net primary production is the rate at which new biomass is generated, mainly due to photosynthesis. Global primary production can be estimated from satellite observations. Satellites scan the normalised difference vegetation index (NDVI) over terrestrial habitats, and scan sea-surface chlorophyll levels over oceans. This results in 56.4 billion tonnes C/yr (53.8%), for terrestrial primary production, and 48.5 billion tonnes C/yr for oceanic primary production.[6] Thus, the total photoautotrophic primary production for the Earth is about 104.9 billion tonnes C/yr. This translates to about 426 gC/m²/yr for land production (excluding areas with permanent ice cover), and 140 gC/m²/yr for the oceans.

However, there is a much more significant difference in standing stocks—while accounting for almost half of total annual production, oceanic autotrophs account for only about 0.2% of the total biomass. Autotrophs may have the highest global proportion of biomass, but they are closely rivaled or surpassed by microbes.[49][50]

Terrestrial freshwater ecosystems generate about 1.5% of the global net primary production.[51]

Some global producers of biomass in order of productivity rates are

Producer Biomass productivity
Ref Total area
(million km²)
Ref Total production
(billion tonnes C/yr)
Swamps and marshes 2,500 [3]
Tropical rainforests 2,000 [52] 8 16
Coral reefs 2,000 [3] 0.28 [53] 0.56
Algal beds 2,000 [3]
River estuaries 1,800 [3]
Temperate forests 1,250 [3] 19 24
Cultivated lands 650 [3][54] 17 11
Tundras 140 [3][54]
Open ocean 125 [3][54] 311 39
Deserts 3 [54] 50 0.15

See also


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  40. ^ FAO Statistical Yearbook 2013: page 130 -
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Further reading

External links

Ancient woodland

In the United Kingdom, an ancient woodland is a woodland that has existed continuously since 1600 or before in England, Wales and Northern Ireland (or 1750 in Scotland). Before those dates, planting of new woodland was uncommon, so a wood present in 1600 was likely to have developed naturally.In most ancient woods, the trees and shrubs have been cut down periodically as part of the management cycle. Provided that the area has remained as woodland, the stand is still considered ancient. Since it may have been cut over many times in the past, ancient woodland does not necessarily contain very old trees.For many species of animal and plant, ancient woodland sites provide the sole habitat, and for many others, conditions on these sites are much more suitable than those on other sites. Ancient woodland in the UK, like rainforest in the tropics, is home to rare and threatened species. For these reasons ancient woodland is often described as an irreplaceable resource, or 'critical natural capital'. The analogous term used in the United States is "Old-growth forest".Ancient woodland is formally defined on maps by Natural England and equivalent bodies. Mapping of ancient woodland has been undertaken in different ways and at different times, and the quality and availability of data varies from region to region, although there are some efforts to standardise and update it.

Arrocampo Reservoir

(This article is a summary translation of Spanish article Embalse de Arrocampo of Wikipedia (es))

The Arrocampo Reservoir, (embalse de Arrocampo or embalse de Arrocampo-Almaraz in Spanish), is located in the province of Cáceres, Extremadura, Spain.

It was created at 1976 to refrigerate the turbines of the Almaraz Nuclear Power Plant.

The nearest municipalities are Almaraz, Romangordo, Saucedilla and Serrejón.

The dam is on the Arrocampo River (arroyo Arrocampo), very close to where this little river joins the Tagus.


Biomass is plant or animal material used for energy production, heat production, or in various industrial processes as raw material for a range of products. It can be purposely grown energy crops (e.g. miscanthus, switchgrass), wood or forest residues, waste from food crops (wheat straw, bagasse), horticulture (yard waste), food processing (corn cobs), animal farming (manure, rich in nitrogen and phosphorus), or human waste from sewage plants.Burning plant-derived biomass releases CO2, but it has still been classified as a renewable energy source in the EU and UN legal frameworks because photosynthesis cycles the CO2 back into new crops. In some cases, this recycling of CO2 from plants to atmosphere and back into plants can even be CO2 negative, as a relatively large portion of the CO2 is moved to the soil during each cycle.

Cofiring with biomass has increased in coal power plants, because it makes it possible to release less CO2 without the cost assosicated with building new infrastructure. Co-firing is not without issues however, often an upgrade of the biomass is beneficiary. Upgrading to higher grade fuels can be achieved by different methods, broadly classified as thermal, chemical, or biochemical (see below).


Bioproducts or bio-based products are materials, chemicals and energy derived from renewable biological resources.


Biorefining is the process of "refining" multiple products from biomass as a feedstock or raw material much like a petroleum refinery that is currently in use. A biorefinery is a facility like a petroleum refinery that comprises the various process steps or unit operations and related equipment to produce various bioproducts including fuels, power, materials and chemicals from biomass. Industrial biorefineries have been identified as the most promising route to the creation of a new domestic biobased industry producing entire spectrum of bioproducts or bio-based products.

Biomass has various components such as lignin, cellulose, hemicellulose, extractives, etc. Biorefinery can take advantage of the unique properties of each of biomass components enabling the production of various products. The various bioproducts can include fiber, fuels, chemicals, plastics etc.

Ecological engineering

Ecological engineering uses ecology and engineering to predict, design, construct or restore, and manage ecosystems that integrate "human society with its natural environment for the benefit of both".


Ecotechnology – not to be confused with ecotechnics – is an applied science that seeks to fulfill human needs while causing minimal ecological disruption, by harnessing and manipulating natural forces to leverage their beneficial effects. Ecotechnology integrates two fields of study: the 'ecology of technics' and the 'technics of ecology,' requiring an understanding of the structures and processes of ecosystems and societies. All sustainable engineering that can reduce damage to ecosystems, adopt ecology as a fundamental basis, and ensure conservation of biodiversity and sustainable development may be considered as forms of ecotechnology.

Ecotechnology emphasizes approaching a problem from a holistic point of view. For example, remediation of rivers should not only consider one single area. Rather, the whole catchment area, which includes the upstream, middle stream and downstream sections, should be considered.

Construction can reduce its impact on nature by consulting experts on the environment.

Sustainable development requires the implementation of environmentally friendly technologies which are both efficient and adapted to local conditions. Ecotechnology allows improvement in economic performance while minimizing harm to the environment by:

increasing the efficiency in the selection and use of materials and energy sources

control of impacts on ecosystems

development and permanent improvement of cleaner processes and products


introducing environmental management systems in the production and services sectors

development of activities for increasing awareness of the need for environmental protection and promotion of sustainable development by the general publicDuring Ecotechnics '95 - International Symposium on Ecological Engineering in Östersund, Sweden, the participants agreed on the definition: "Ecotechnics is defined as the method of designing future societies within ecological frames."


A forest is a large area dominated by trees. Hundreds of more precise definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function. According to the widely used Food and Agriculture Organization definition, forests covered 4 billion hectares (9.9×109 acres) (15 million square miles) or approximately 30 percent of the world's land area in 2006.Forests are the dominant terrestrial ecosystem of Earth, and are distributed around the globe. Forests account for 75% of the gross primary production of the Earth's biosphere, and contain 80% of the Earth's plant biomass. Net primary production is estimated at 21.9 gigatonnes carbon per year for tropical forests, 8.1 for temperate forests, and 2.6 for boreal forests.Forests at different latitudes and elevations form distinctly different ecozones: boreal forests near the poles, tropical forests near the equator and temperate forests at mid-latitudes. Higher elevation areas tend to support forests similar to those at higher latitudes, and amount of precipitation also affects forest composition.

Human society and forests influence each other in both positive and negative ways. Forests provide ecosystem services to humans and serve as tourist attractions. Forests can also affect people's health. Human activities, including harvesting forest resources, can negatively affect forest ecosystems.

Index of fishing articles

This page is a list of fishing topics.


In engineering, macro-engineering (alternatively known as macroengineering or macro engineering and as mega engineering) is the implementation of extremely large-scale design projects. It can be seen as a branch of civil engineering or structural engineering but just on a very large land area. In particular, macro-engineering is the process of marshaling and managing of resources, technology and public opinion on a large scale to carry out complex tasks that last over a long period.

In contrast to conventional engineering projects, macro-engineering projects (called macro-projects or mega-projects) are multidisciplinary, involving collaboration from all fields of study; they involve not only engineers, but scientists, lawyers, industrialists, soldiers and politicians as well. Macro-projects are usually international; they override political boundaries because most countries lack the social, financial or physical ability to undertake them alone. As a consequence, macro-projects have the power to fundamentally transform its area of focus.

Macro-engineering is an evolving field that is only recently receiving attention. Because we routinely deal with challenges that are multinational in scope, such as global warming and pollution, macro-engineering is emerging as a transcendent solution to worldwide problems. Macro-engineering, or mega-engineering, is distinct from megascale engineering which deals with projects on a planetary or stellar scale. Where macro-engineering is currently practical, mega-scale engineering is still within the domain of speculative fiction.

Non-timber forest product

Non-timber forest products (NTFPs), also known as non-wood forest products (NWFPs), minor forest produce, special, minor, alternative and secondary forest products, are useful substances, materials and/or commodities obtained from forests which do not require harvesting (logging) trees. They include game animals, fur-bearers, nuts, seeds, berries, mushrooms, oils, foliage, pollarding, medicinal plants, peat, mast, fuelwood, fish, spices, and forage.Research on NTFPs has focused on their ability to be produced as commodities for rural incomes and markets, as an expression of traditional knowledge or as a livelihood option for rural household needs, and as a key component of sustainable forest management and conservation strategies. All research promotes forest products as valuable commodities and tools that can promote the conservation of forests.

Productivity (ecology)

In ecology, productivity refers to the rate of generation of biomass in an ecosystem. It is usually expressed in units of mass per unit surface (or volume) per unit time, for instance grams per square metre per day (g m−2 d−1). The mass unit may relate to dry matter or to the mass of carbon generated. Productivity of autotrophs such as plants is called primary productivity, while that of heterotrophs such as animals is called secondary productivity.


Saucedilla (Spanish pronunciation: [sau̯.θeˈði.ʎa]) is a municipality located in the province of Cáceres, Extremadura, Spain. According to the 2010 census (INE), it has a population of 859 inhabitants.

It belongs to the Campo Arañuelo County (Comarca del Campo Arañuelo), the capital of which is Navalmoral de la Mata.

Standing crop

A standing crop is the total dried biomass of the living organisms present in a given environment.

Standing stock

Standing stock may refer to:

Biomass (ecology) of a stock of organisms

Population density, a measurement of population per unit area or unit volume

Livestock crush, British English for the device called a stock or standing stock in the USA, used for restraining livestock

Trophic state index

Trophic State Index (TSI) is a classification system designed to rate bodies of water based on the amount of biological activity they sustain. Although the term "trophic index" is commonly applied to lakes, any surface body of water may be indexed.

The TSI of a body of water is rated on a scale from zero to one hundred. Under the TSI scale, bodies of water may be defined as:

oligotrophic (TSI 0–40, having the least amount of biological productivity, "good" water quality);

mesoeutrophic (TSI 40–60, having a moderate level of biological activity, "fair" water quality); or

eutrophic to hypereutrophic (TSI 60–100, having the highest amount of biological activity, "poor" water quality).The quantities of nitrogen, phosphorus, and other biologically useful nutrients are the primary determinants of a body of water's TSI. Nutrients such as nitrogen and phosphorus tend to be limiting resources in standing water bodies, so increased concentrations tend to result in increased plant growth, followed by corollary increases in subsequent trophic levels. Consequently, a body of water's trophic index may sometimes be used to make a rough estimate of its biological condition.


Wildcrafting (also known as foraging) is the practice of harvesting plants from their natural, or 'wild' habitat, primarily for food or medicinal purposes. It applies to uncultivated plants wherever they may be found, and is not necessarily limited to wilderness areas. Ethical considerations are often involved, such as protecting endangered species, potential for depletion of commonly held resources, and in the context of private property, preventing theft of valuable plants, for example, ginseng.

When wildcrafting is done sustainably and with proper respect, generally only the fruit, flowers or branches from plants are taken and the living plant is left, or if it is necessary to take the whole plant, seeds of the plant are placed in the empty hole from which the plant was taken. Care is taken to remove only a few plants, flowers, or branches, so plenty remains to continue the supply. The Association of Foragers believes that foraging by people plays an increasingly important role supporting, promoting and defending the health of all plants, fungi, algae, animals (including humans) and the habitats/environments in which they exist. Plants for a Future database lists 7000 plants with edible, medicinal or other uses. In the USA, the mission of United Plant Savers is to protect native medicinal plants of the United States and Canada (such as Goldenseal) and their native habitat while ensuring an abundant renewable supply of medicinal plants for generations to come.Four states and five national forests in America actively manage the wild harvesting of ginseng to ensure sustainability of wild populations. In Europe, non-wood forest products (e.g., forest fruits, mushroom, cork, pine kernels, acorns, medicinal herbs, essential oils, chestnuts etc.) can be significant in the bioeconomy, especially in regions where wood is not the most profitable product. These were examined during a four year study called The StarTree Project which assessed the wildcrafting of non-timber forest products across 14 regions of Europe to explore best practice and commercial opportunities.There is no evidence that foraging in small amounts for personal use by people and their families has any impact on populations of plants and fungi. However, once a species attracts widespread commercial interest it can quickly come under pressure if sustainable harvesting and management procedures are not followed. A case in point is Arnica, a medicinal species made into homeopathic remedies and highly popular first aid creams for bumps and bruises. It is now under strict protection and is included in the IUCN Red List of Threatened Species and in the Red Data Books and Red Data Lists of many European countries. Despite the loss of habitats, Arnica is mainly harvested from the wild. Dried flowers traded annually in Europe are estimated to be around 50 tonnes. The collection of Arnica for medicinal purposes has also caused disappearance or reduction in the size of several European populations. The pressure on natural sources of this plant is alleviated by a suitable use of Arnica supply in the European region, where flower heads are harvested.


A woodland (listen) or wood (or in the U.S., the plurale tantum woods) is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of primary or secondary succession. Higher density areas of trees with a largely closed canopy that provides extensive and nearly continuous shade are referred to as forests.

Extensive efforts by conservationist groups have been made to preserve woodlands from urbanization and agriculture: the woodlands of Northwest Indiana being an example, having been preserved as part of the Indiana Dunes.

Food webs
Example webs
Ecology: Modelling ecosystems: Other components
Aquatic ecosystems

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