Energy Transfer

In 1927, the British ecologist Charles Elton wrote that most food webs have a similar pyramidal shape. At the bottom, there are many photosynthetic organisms which collectively have a large biomass and productivity. On each of the following trophic levels, or feeding levels, there are successively fewer heterotrophic organisms, with a smaller productivity. The pyramid of biomass and productivity is now known as the Eltonian pyramid.

In 1942, Raymond L. Lindeman published a paper that examined food webs in terms of energy flow. Lindeman proposed that, by using energy as the currency of ecosystem processes, food webs could be quantified. This allowed him to explain that the Eltonian pyramid was a result of successive energy losses associated with the thermodynamic inefficiencies of energy transfer among trophic levels.

Current research in ecological energy transfer focuses on increasing our understanding of the paths of energy and matter within grazing and microbial food webs. Rather little is understood about such pathways because of the huge numbers of species and their complex interactions. This understanding is essential for proper management of ecosystems. The fate and effects of toxic chemicals within food webs must be understood if impacts on vulnerable species and ecosystems are to avoided or minimized.