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Author(s): Deanne Erdmann MS

Ecological Pyramids of Biomass

The total dry weight of organisms (standing crop) in a particular trophic level is referenced as biomass. Most pyramids follow the typical pattern of narrowing at each level, however in some aquatic ecosystems, the pyramid may be inverted. In the example, phytoplankton grow and reproduce so rapidly that they can support a large population of zooplankton even though at any one time, the biomass of phytoplankton is smaller than that of the zooplankton.