Use of eco-exergy in ecological networks

•Eco-exergy can be used in ecological network to depict the transfer processes.•The total work energy (eco-exergy) should include the work energy of the information.•A network with eco-exergy depicts total system through flow (TST) of all the work energy.•The work energy including information are distributed to the entire network.

Eco-exergy (EE) has previously been used in ecological network calculations. It is the work energy including the work energy of the embodied information. Eco-exergy is calculated for living organisms as β × B × f kJ, where β is covering the information contained in the genome, B is the biomass (for instance in g) and f is the work energy per unit of biomass, which on average is 18.7 kJ/g. The β-value is a weighting factor that expresses the ratio between the work energy of an organism including the work energy of the embodied information and the work energy of the biomass. The work energy of information transfer is, however, different for the donor and the receptor. This is in part because the receptor uses the work energy to grow, which means it gains the work energy including the information on the level of the receptor while the donor is losing the work energy including the information of the donor. This difference between the donor and recipient has to be considered when we illustrate the ecological networks, their respective transfer processes, and their total system throughflows (TST). It is also critical when we determine the eco-exergy (EE), which is equal to the work energy including the information stored in the network. Two examples are used to illustrate the differences between ecological networks, based on either donor determined work energy including information or on work energy, where the donor and receptor determined work energy of information are different due to differences in the β-values. The results of the latter are presumed to give the correct calculations of the transfer processes in ecological networks.