The enactment of the Water Framework Directive (WFD) initiated scientific efforts to develop reliable methods for comparing prevailing lake conditions against reference (or nonimpaired) states, using the state of a set biological elements. Drawing a distinction between impaired and natural conditions can be a challenging exercise. Another important aspect is to ensure that water quality assessment is comparable among the different Member States. In this context, the present paper offers a constructive critique of the practices followed during the WFD implementation in Greece by pinpointing methodological weaknesses and knowledge gaps that undermine our ability to classify the ecological quality of Greek lakes. One of the pillars of WDF is a valid lake typology that sets ecological standards transcending geographic regions and national boundaries. The national typology of Greek lakes has failed to take into account essential components. WFD compliance assessments based on the descriptions of phytoplankton communities are oversimplified and as such should be revisited. Exclusion of most chroococcal species from the analysis of cyanobacteria biovolume in Greek lakes/reservoirs and most reservoirs in Spain, Portugal, and Cyprus is not consistent with the distribution of those taxa in lakes. Similarly, the total biovolume reference values and the indices used in classification schemes reflect misunderstandings of WFD core principles. This hampers the comparability of ecological status across Europe and leads to quality standards that are too relaxed to provide an efficient target for the protection of Greek/transboundary lakes such as the ancient Lake Megali Prespa.

中文翻译：

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水框架指令的实施：根据地中海地区希腊湖泊状况的浮游植物进行具有生态意义的分类的经验教训和未来展望

水框架指令 (WFD) 的颁布启动了科学努力，以开发可靠的方法，使用一组生物元素的状态将盛行的湖泊条件与参考（或未受损）状态进行比较。区分受损条件和自然条件可能是一项具有挑战性的工作。另一个重要方面是确保水质评估在不同成员国之间具有可比性。在这种情况下，本文通过指出破坏我们对希腊湖泊生态质量进行分类的能力的方法论弱点和知识差距，对希腊实施 WFD 期间所遵循的做法提出了建设性的批评。WDF 的支柱之一是有效的湖泊类型，它设定了超越地理区域和国界的生态标准。希腊湖泊的国家类型没有考虑到基本组成部分。基于浮游植物群落描述的 WFD 合规性评估过于简单化，因此应重新审视。从希腊湖泊/水库和西班牙、葡萄牙和塞浦路斯的大多数水库中的蓝藻生物量分析中排除大多数慢性球菌物种与这些分类群在湖泊中的分布不一致。同样，总生物量参考值和分类方案中使用的指数反映了对 WFD 核心原则的误解。这阻碍了整个欧洲生态状况的可比性，并导致质量标准过于宽松，无法为保护古梅加利普雷斯帕湖等希腊/跨界湖泊提供有效目标。