Biomass
Definition and meaning of Biomass in chemistry.
Biomass is the total mass of living or once-living material in a given area, ecosystem, or sample. Scientists usually measure it as dry weight, after removing water, so different samples can be compared fairly. It includes plants, animals, and microorganisms, often reported per unit of area or volume.
In more detail
Biomass is a core measurement in ecology because it reflects how much living matter an ecosystem can support. Producers, mainly plants and algae, capture energy from sunlight through photosynthesis and convert it into new tissue. This tissue becomes food for primary consumers, such as herbivores.
Primary consumers are in turn eaten by secondary consumers like predators. At each step up this food chain, only a fraction of the biomass and energy transfers to the next level. This fraction is usually around ten percent.
This is why plant biomass dominates most terrestrial ecosystems. Top predators make up only a tiny share of total biomass. The term also describes organic material used as a renewable energy source.
Wood, crop residue, animal waste, and algae can all be burned or converted into fuels like ethanol and biogas. This use connects ecology to energy science, since both track the same stored chemical energy. A common misconception is that biomass and biodiversity mean the same thing.
Biomass measures total mass, while biodiversity measures the variety of species present. A field of a single crop can have huge biomass but very low biodiversity. Tracking biomass over time also helps scientists monitor deforestation and crop yields. It also shows how ecosystems recover after disturbances like fires or droughts.
Key facts
| Field | Biochemistry / Ecology |
|---|---|
| Common unit | grams per square meter or metric tons per hectare |
| Main elements present | Carbon, hydrogen, oxygen, nitrogen |
| Energy transfer between levels | About 10% per trophic level |
| Renewable energy use | Wood, crop residue, algae, biogas |
| Not the same as | Biodiversity (species variety) |
A temperate forest might have a total biomass of about 200 metric tons per hectare. Trees typically make up around 95 percent of that mass. Herbivores, carnivores, and decomposers together account for a much smaller share.
Frequently asked questions
How does biomass differ from biodiversity?
Biomass measures the total mass of living things in an area. Biodiversity measures the variety and number of different species present, which is a separate idea.
Why do scientists measure biomass?
Biomass measurements show how productive and healthy an ecosystem is. They help scientists track deforestation, manage resources, and judge whether bioenergy crops are sustainable.
Why does biomass decrease at higher trophic levels?
Only about ten percent of the energy and mass at one feeding level typically transfers to the next. Most energy is lost as heat or used for the organism's own life processes.