Abstract
The results of an investigation of the energy values of 42 species of benthic and planktonic invertebrates from 12 phyla indicates that there is a significant higher average energy content per unit dry weight and ash-free dry weight in planktonic forms. The energy content was closely correlated to the proportion of organic matter in both groups, but several planktonic species displayed exceptionally high values. This can be explained by the ability to store large amounts of lipids in these species.