According to the European Water Framework Directive (WFD), restoration actions are needed if the present-day ecological quality status (EcoQS) is worse than good. However, less stringent environmental objectives may be allowed if the water body’s natural condition is such that it may be unfeasible or unreasonably expensive to achieve good conditions.

In the Inner Skjolda- and Grindefjord, an isolated and shallow silled fjordsystem on the SW coast of Norway, the present EcoQS (based on benthic foraminifera and macroinvertebrates) is bad due to anoxic conditions in the bottom water. Paleoecological foraminiferal data in two dated sediment records were used to establish in situ reference conditions. The data revealed that the current bad EcoQS did not deviate from the natural reference condition which existed just prior to the onset of the industrial revolution. Further back in time, the record showed poor EcoQS and a strong dominance of the opportunistic foraminiferal species Stainforthia fusiformis, indicating unfavorable conditions for benthic foraminifera already >2000 years ago. The changing ecological status during the pre-industrial period was probably caused by the inner fjordsystem becoming gradually more isolated and stratified, and the bottom water more stagnant with decreasing oxygen concentrations, in response to isostatic uplift. Our study shows that reference conditions at a location may represent a natural succession of environmental changes i.e., the natural baseline does not have to represent only one environmental condition but may vary naturally over time. We therefore suggest that the conditions just prior to the onset of the industrial revolution should be used when defining reference conditions according to the WFD.

根据欧洲水框架指令 (WFD)，如果当前的生态质量状况 (EcoQS) 不如好，则需要采取恢复行动。但是，如果水体的自然条件使得实现良好条件可能不可行或成本过高，则可以允许不太严格的环境目标。

Inner Skjolda- 和 Grindefjord 是挪威西南海岸的一个孤立的浅峡湾系统，由于底水缺氧，目前的 EcoQS（基于底栖有孔虫和大型无脊椎动物）很糟糕。两个年代久远的沉积物记录中的古生态有孔虫数据用于建立原位参考条件。数据显示，当前糟糕的 EcoQS 并没有偏离工业革命开始前就存在的自然参考条件。更早的时候，记录显示 EcoQS 较差，机会性有孔虫物种Stainforthia fusiformis占主导地位，表明底栖有孔虫的不利条件已经 > 2000 年前。工业化前时期生态状况的变化可能是由于内部峡湾系统逐渐变得更加孤立和分层，底水随着氧气浓度的降低而更加停滞，以响应均衡抬升。我们的研究表明，一个位置的参考条件可能代表自然连续的环境变化，即自然基线不必只代表一种环境条件，而是可能随时间自然变化。因此，我们建议在根据 WFD 定义参考条件时，应使用工业革命开始之前的条件。