A different perspective in metabolic ecology is presented using food web data, based on trophic compartments and communities in aquatic ecosystems (coastal areas, shelves and estuaries in marine ecosystems, and lake ecosystems), including primary producers (phytoplankton and aquatic plants). The relationships among the metabolic traits (biomass, respiration and production) in aquatic communities are expressed through power laws, hence, the value of one of the three metabolic traits provides the values of the other two. Noteworthily, these metabolic traits (biomass, respiration, production) are related to those of primary producers according to various power laws. That is: the metabolic traits of communities can be estimated from those of primary producers alone. These power laws appear to be universal in marine ecosystems but vary among different lake ecosystems.