Biomass (ecology)

This article is about the ecological measure. For the renewable energy source, see Biomass (energy).

The total global live biomass has been estimated at 550 billion tonnes carbon, most of which is found in forests.
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.

Biomass is the total mass of living biological organisms in a given area or ecosystem at a specific time. Biomass may refer to the 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 encompasses microorganisms, plants, and animals, and is typically expressed as total mass or average mass per unit area.

The method used to measure biomass depends on the context. In some cases, biomass refers to the wet weight of organisms as they exist in nature. 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. In other contexts, it may refer to dry weight (excluding water content), or to the mass of organic carbon, excluding inorganic components such as bones, shells, or teeth.

In 2018, Bar-On et al. estimated Earth's total live biomass at approximately 550 billion tonnes of carbon, the majority of which is found in plants. A 1998 study by Field et al. estimated global annual net primary production at just over 100 billion tonnes of carbon per year. While bacteria were once believed to account for a biomass comparable to that of plants, more recent research indicates they represent a much smaller proportion. The total number of DNA base pairs on Earth – sometimes used as a possible approximation of global biodiversity – has been estimated at (5.3±3.6)×1037, with a mass of around 50 billion tonnes. By the year 2020, the mass of human-made materials or anthropogenic mass, defined as "the mass embedded in inanimate solid objects made by humans (that have not yet been demolished or taken out of service)", was projected to surpass that of all living biomass on Earth.

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