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The implementation of the Water Framework Directive requires EU member states to establish and harmonize ecological status class boundaries for biological quality elements. In this paper, we describe an approach for defining ecological class boundaries that delineates shifts in lake ecosystem functioning and, therefore, provides ecologically meaningful targets for water policy in Europe., We collected an extensive data set of 810 lake-years from nine Central European countries, and we used phytoplankton chlorophyll a, a metric widely used to measure the impact of eutrophication in lakes. Our approach establishes chlorophyll a target values in relation to three significant ecological effects of eutrophication: the decline of aquatic macrophytes, the dominance of potentially harmful cyanobacteria and the major functional switch from a clear water to a turbid state., Ranges of threshold chlorophyll a concentrations are given for the two most common lake types in lowland Central Europe: for moderately deep lakes (mean depth 3-15 m), the greatest ecological shifts occur in the range 10-12 μg L−1 chlorophyll a, and for shallow lakes (<3 m mean depth), in the range 21-23 μg L−1 chlorophyll a., Synthesis and applications. Our study provides class boundaries for determining the ecological status of lakes, which have robust ecological consequences for lake functioning and which, therefore, provide strong and objective targets for sustainable water management in Europe. The results have been endorsed by all participant member states and adopted in the European Commission legislation, marking the first attempt in international water policy to move from physico-chemical quality standards to harmonized ecologically based quality targets. [ABSTRACT FROM AUTHOR]

The Prince Edward Islands (PEIs) lie within the Antarctic Circumpolar Current (ACC), in a transition zone bordered by the sub‐Antarctic Front (SAF) to the north and the Antarctic Polar Front (APF) in the south. A climate‐driven southward shift of the ACC and its frontal systems, the SAF and APF, in the vicinity of the PEIs is associated with a long‐term decline in the frequency of island‐associated phytoplankton blooms. These oceanographic perturbations coincide with significant declines in top predator populations attributed to shifts in the distribution and availability of prey, illustrating the interconnectedness between the marine and terrestrial ecosystems of the PEIs. This study investigated the influence of oceanographic variability on the marine ecosystem of the PEIs. A shift in phytoplankton and bacterial communities was observed that coincides with the position of the southern branch of the SAF, which was located to the north of the PEIs during 2014 and to the south during 2012, 2013, and 2015. These shifts in the diversity and structure of marine microbial communities correlate with significant perturbations in the position of the SAF relative to the islands leading us to conlclude that bacterial and phytoplankton communities in the PEI region are strongly influenced by shifts in the position of the SAF relative to the PEIs. This study highlights the critical need to link on‐going physical time series measurements with biological observations to provide a better understanding of the direct role that the upstream dynamics has on the near‐shore island environment and its productivity. [ABSTRACT FROM AUTHOR]

The Water Framework Directive is the first international legislation to require European countries to establish comparable ecological assessment schemes for their freshwaters. A key element in harmonising quality classification within and between Europe's river basins is an “Intercalibration” exercise, stipulated by the WFD, to ensure that the good status boundaries in all of the biological assessment methods correspond to similar levels of anthropogenic pressure. In this article, we provide a comprehensive overview of this international comparison, focusing on the assessment schemes developed for freshwater lakes. Out of 82 lake ecological assessment methods reported for the comparison, 62 were successfully intercalibrated and included in the EC Decision on intercalibration, with a high proportion of phytoplankton (18), macrophyte (17) and benthic fauna (13) assessment methods. All the lake assessment methods are reviewed in this article, including the results of intercalibration. Furthermore, the current gaps and way forward to reach consistent management objectives for European lakes are discussed. [ABSTRACT FROM AUTHOR]