Nielsen Kurt, Sømod Bent, Ellegaard Christina, Krause-Jensen Dorte
National Environmental Research Institute, Department of Lake and Estuarine Ecology, Silkeborg, Denmark.
Ambio. 2003 Jun;32(4):287-94. doi: 10.1579/0044-7447-32.4.287.
The European Water Framework Directive (WFD) requires the definition of reference conditions, i.e. pristine conditions, for all surface waters. As the present state of Danish coastal waters cannot be referred to as pristine, reference conditions have to be assessed by analysis of historical data or by the use of models. Using Randers Fjord as an example, the aim of this work was i) to demonstrate possibilities and restrictions of assessing reference conditions by historical data and by modelling; and ii) to demonstrate how ecological conditions have changed along with eutrophication. The ample historical data from Randers Fjord allowed us to assess reference conditions with respect to benthic macrophytes and benthic fauna. Models of varying complexity enabled us to assess reference conditions for nutrients, chlorophyll a, Secchi depth, and eelgrass. We conclude that models can be a useful supplement to assess reference conditions, though they are presently restricted by the lack of quantitative links between eutrophication and species composition.
欧洲水框架指令（WFD）要求为所有地表水定义参考条件，即原始条件。由于丹麦沿海水域的现状不能被视为原始状态，因此必须通过分析历史数据或使用模型来评估参考条件。以兰讷斯峡湾为例，这项工作的目的是：i）展示通过历史数据和建模评估参考条件的可能性和局限性；ii）展示生态条件如何随着富营养化而变化。兰讷斯峡湾丰富的历史数据使我们能够评估底栖大型植物和底栖动物的参考条件。不同复杂程度的模型使我们能够评估营养物质、叶绿素a、塞氏深度和鳗草的参考条件。我们得出结论，尽管目前模型因富营养化与物种组成之间缺乏定量联系而受到限制，但它们可以作为评估参考条件的有用补充。
