Calculations of exergy for organisms

Abstract

Exergy estimations based on biomass and information for organisms can with good approximation be found as: Ex = [beta]c, where c is the concentration of biomass and [beta] the weighting factor, that accounts for the information that the organisms carry [Jørgensen, S.E., 2002. Integration of Ecosystem Theories: A Pattern, vol. 432, 3rd ed. Kluwer Academic Publishing Company, Dordrecht, The Netherlands]. The determination of [beta] for various organisms has been based on the number of coding genes, but recent research has shown that some of the non-coding genes are crucial for the control, maintenance and development of the organisms. The results [Eichler, E.E., Sankoff, D., 2003. Structural dynamics of eukaryotic chromosome evolution. Science 301, 793-797.] of ongoing whole-genome projects have therefore be applied in order to obtain more accurate [beta]-values. These new [beta]-values are several times bigger than the previously applied values. The number of amino acids coding per gene has probably been underestimated in the previous calculations. However, applications of the former values, for instance in ecosystem health assessment, where exergy is used as ecological indicator (referred as exergy index) and in the development of structurally dynamic models, are still valid. Because the exergy calculations were applied only as relative measures.