Abstract
Adopting the theories and methods of emergy analysis, the annual average emergy input-output of the Lake Nansi wetland
ecosystem is calculated. Further, the emergy analysis chart is drawn to evaluate the energy flow and the economic value of the
lake. The structure and functions of the Lake Nansi wetland ecosystem are analyzed as a whole. The results showed that the
amount of the input solar emergy (including sunlight, wind and rainfall) of the Lake Nansi is 1.11×1021 1021 solar emergy
joule/year (sej/a), and the output solar emergy is 1.73×1020sej/a. The primary productivity is 1.61×1020sej/a. Non-renewable
resources is 1.03×1021 sej/a. At the same time, the ecological benefits of aquatic vascular plants and fish of the Lake Nansi are
significant. The energy investment ratio of the lake is 0.0009. The net emergy yield ratio is 165.23 and environmental load ratio is
14.22. The high net emergy yield ratio and environmental load ratio show that Lake Nansi wetland ecosystem has a great
contribution to local economy. The regional economic development is low and vastly depends on nature environment.