储存于遗传信息中的能值和埃三级.pdf

Ecological Modelling 178 (2004) 11–16 Emergy and exergy stored in genetic information S.E. Jorgensen a,1, H.T. Odumb , M.T. Brownb,∗ a DFH, Environmental Chemistry, University Park 2, 2100 Copenhagen, Denmark b Department of Environmental Engineering Sciences, University of Florida, Post Box 116350, Gainesville, FL 32611-6350, USA Abstract The emergy and exergy of genetic information and its biological carriers are evaluated. Emergy used to build and maintain biological organisms (which we suggest are the carriers of genetic information analogous to books or a communications network) was evaluated on an areal basis using average global emergy input to the biosphere. The chemical exergy of genes is calculated relative to detritus as the reference environment. Using generalized data for populations of organisms from bacteria to large mammals, an emergy–exergy ratio for genes and solar transformities of biomass are calculated. The exergy used to maintain genetic information is shown to be between about 0.1 and 1000 MJ/m2 . The emergy–exergy ratio for gene maintenance (a measure of the emergy required per Joule of genetic information is between about 1.0 and 20,000 sej/J. Generalized solar transformities for organisms are calculated and vary between about 2 sej/J of biomass (soil bacteria) to 75 million sej/J (mammel biomass). An interesting relationship between the emergy costs of gene maintenance and the solar transformity of biomass leads us to conclude that as the complexity of the biological carrier of information increases, the emergy costs of maintaining the carrier increases faster than the information carried. We propose that the emergy required to generate the genetic information contained in the biosphere today is eno