Xu Fu-Liu, Dawson R W, Tao Shu, Li Ben-Gang, Cao Jun
Department of Urban and Environmental Sciences, Peking University, Beijing, China.
Chemosphere. 2002 Jan;46(2):173-85. doi: 10.1016/s0045-6535(01)00127-8.
This paper presents the system-level responses of experimental lake ecosystems to three chemical stresses (acidification, copper and pesticide contamination) using exergy and structural exergy as ecological indicators. The results indicate that the doses or toxicity of the three chemical stressors contributed to changes in both exergy and structural exergy. Remarkable changes in exergy and structural exergy occurred under acidic conditions and in the presence of Dursban, 24D-DMA, permethrin, bifenthrin, Carbaryl, TCP, PCP, trichlorethylene, benzene, and high doses of Cu, oil, and hexazinone. This seemed to indicate that the subject ecosystems were seriously contaminated by these chemical stressors. For low doses of Cu, oil, atrazine, HCBP, and hexazinone, exergy and structural exergy were either unchanged or only slightly changed, suggesting that the lake ecosystems were not significantly impacted by these chemical stressors. Discussion of the relationships between ecosystem-level changes and structural and functional changes in stressed lake ecosystems indicates that the above-mentioned ecosystem-level changes were in accordance with the changes in structure and function. The observed changes in exergy and structural exergy were also consistent with Odum's predictions of shortened food chains, reduced resource use efficiency, poor stability, low information, and high entropy in stressed aquatic ecosystems. The findings lead the authors to conclude that it is feasible for exergy and structural exergy to serve as ecological indicators when characterizing the system-level responses of experimental lake ecosystems to chemical stress. These results for experimental lake ecosystems would be extrapolated to actual lakes.
本文以火用和结构火用作为生态指标，展示了实验湖泊生态系统对三种化学胁迫（酸化、铜污染和农药污染）的系统级响应。结果表明，这三种化学胁迫因子的剂量或毒性导致了火用和结构火用的变化。在酸性条件下以及存在毒死蜱、2,4-滴二甲胺盐、氯菊酯、联苯菊酯、西维因、三氯苯酚、五氯苯酚、三氯乙烯、苯以及高剂量的铜、油和嗪草酮时，火用和结构火用发生了显著变化。这似乎表明受试生态系统受到了这些化学胁迫因子的严重污染。对于低剂量的铜、油、阿特拉津、六氯苯和嗪草酮，火用和结构火用要么没有变化，要么只有轻微变化，这表明湖泊生态系统未受到这些化学胁迫因子的显著影响。对受胁迫湖泊生态系统中生态系统层面变化与结构和功能变化之间关系的讨论表明，上述生态系统层面的变化与结构和功能的变化是一致的。观察到的火用和结构火用的变化也与奥德姆对受胁迫水生生态系统中食物链缩短、资源利用效率降低、稳定性差、信息少和熵高的预测一致。这些发现使作者得出结论，在表征实验湖泊生态系统对化学胁迫的系统级响应时，火用和结构火用作为生态指标是可行的。实验湖泊生态系统的这些结果将外推至实际湖泊。
