PARENT SESSION
Oral Session # 1: Ecological Theory I: Theory; Scaling.
Presiding: M Pascual
Monday, August 4. 8:00 AM to 11:30 AM, SITCC Meeting Room 100.
Exergy as indicator of ecosystem's integrity.
Debeljak, Marko*,1, 1 Nova Gorica Polytechnic, Nova Gorica, Slovenia, Slovenia
ABSTRACT- Environmental sciences and sustainable management with renewable resources require development of integrated ecosystem theory which can be applied to explain scientifically our observations of nature by few basic natural laws. Comprehensive thermodynamic hypothesis about the processes of ecosystem's growth and development can make significant contribution to this attempt. The research has tested the ability of exergy indicators to assess forest ecosystem's development cycle consist of exploitation, conservation, destruction and renewal development stags. Exergy dissipation was calculated from data obtained with thermal remote sensing of studied plots. Calculation of exergy storage based on genome size of vascular plants of particular development stage. The results have shown that exergy dissipation successfully indicates differences between initial development stages, while exergy storage indicates differences between mature stages of forest ecosystem's development. According to the results, new exergy indicator was proposed: maximum dissipation specific storage of exergy. It is combination of exergy dissipation and exergy storage and gives thermodynamic explanation for complete cycle of forest ecosystem development. Results have been compared with the results of parallel conducted biometric research of the same study plots. The outcome showed supplementing of both results. This was used for evaluation of tentative ecological low of thermodynamic formulated thus: If a system receives a through flow of exergy the system will utilise this exergy flow to move away from thermodynamic equilibrium, and if more then one pathway is offered to move away from thermodynamic equilibrium, the one yielding most storage exergy by the prevailing conditions will have a propensity to be selected. The rigorous examinations of the results have proofed the existence of proposed law. Research has made a new contribution toward formulation of ecosystem theory and integrated development of sustainable management with renewable resources.
Key words: ecosystem, exergy, thermodynamics, sustainability