trofice

Trofice is a theoretical unit used in ecology to quantify the amount of usable energy or biomass transferred from one trophic level to the next within an ecosystem. The term is used in some teaching materials and modeling exercises to illustrate energy flow through food webs and to facilitate comparisons across systems. In energy terms, a trofice can be expressed as joules per square meter per year, or, when biomass is the focus, grams of biomass per square meter per year; the choice of metric depends on the underlying model.

Calculation and interpretation: A trofice value for a given transfer is conceptually the portion of energy or biomass that is actually assimilated by the consumer from the resource, after accounting for losses to respiration and unassimilated material. In practice, trofice is often derived by multiplying the source production by the assimilation efficiency and the transfer efficiency to the next trophic level, though real ecosystems are more complex due to detrital pathways and omnivory.

Applications and limitations: Trofice serves as a convenient teaching or modeling convenience to compare energy transfer across habitats (for example, forests versus oceans). It is not a standard SI unit and is not universally adopted in primary literature; results depend on the definitions of production, efficiency, and system boundaries. Limitations include spatial heterogeneity, seasonal variation, and the omission of detrital or microbial loops.

See also: trophic level, energy flow, ecological efficiency, primary production, trophic transfer.