摘要
《欧洲水框架指令》(WFD)要求确定所有地表水的参考条件,即原始条件。鉴于丹麦沿岸水域的目前状态不能被称为是原始的,因此,必须通过分析历史资料或利用模型来评价参考条件。以兰讷斯峡湾为例,本文的目的是:①论证通过历史资料和模拟评价参考条件的可能性和限制因素;②论证生态条件是如何随着富营养化而改变的,来自兰讷斯峡湾的充分历史资料使我们能够评价与底栖大型植物和底栖动物有关的参考条件。具有不同复杂性的模型使我们能够评价营养物质、叶绿素α、透明度板深度以及大叶藻等的参考条件。我们断定,模型是评价参考条件的有益补充,尽管它们目前由于缺乏富营养化和物种组成之间的定量联系而受到限制。
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.
