Microalgae Growth Inhibition-Based Reservoirs Water Quality Assessment to Identify Ecotoxicological Risks

This work intended to assess the adaptability of bioassay with Raphidocelis subcapitata to be used as a complement to the water quality assessment parameters of reservoirs imposed by the European Water Framework Directive (WFD). Thus, water samples of Portuguese reservoirs (Miranda, Pocinho, Aguieira, and Alqueva) were analyzed in three sampling periods (spring and autumn 2019, and spring 2020). A physical and chemical report of waters was also performed. R. subcapitata assay proved to be sensitive, indicating the presence of a potential perturbation that was not always associated with chemical analysis performed. In general, in the spring samplings, the water samples showed more disturbances to R. subcapitata, which in some situations may be associated with the higher content of nutrients and metals. Microalgae assay can be an effective complementary tool to indicate the ecotoxicological potential since they responded quickly to all sample components of water samples, in a wide-ranging variety of water conditions (different sites in several reservoirs). High similarities between the final ecotoxicological and the ecological potentials, according to the WFD parameters, were detected. The ecotoxicological approach based on our results allowed to confirm that bioassays with R. subcapitata are suitable and sensible to detect perturbations.

The Use of Zooplankton Metrics to Determine the Trophic Status and Ecological Potential: An Approach in a Large Mediterranean Watershed

In the European Water Framework Directive, zooplankton was not included as a Biological Quality Element despite its important place in the aquatic trophic web. In the present study on zooplankton abundances and biomasses, we used several metrics to test their ability to detect differences among trophic statuses and ecological potential levels, and collected a large sum of data in more than 60 reservoirs at Ebro watershed, on more than 300 sampling occasions over 10 years. Our results indicate that most zooplankton metrics are correlated to environmental variables that determine reservoirs’ trophic states, especially chlorophyll a and total phosphorus. The metrics with better sensitivity to differentiate trophic states and ecological potential levels were ZOO (total zooplankton), LZOO (large zooplankton), CLAD (cladocerans), and ZOO:CHLA (zooplankton:chlorophyll a ratio). Microcrustacean metrics such as DAPHN (Daphnia), COP (copepods), CYCLO (cyclopoids), and CALA (calanoids) were good at differentiating between high and low water quality in trophic status (oligotrophic–eutrophic) and ecological potential (good or superior–moderate). Thus, zooplankton can be used as a valuable tool to determine water quality; we believe that zooplankton should be considered a Biological Quality Element within Water Framework Directive monitoring programs for inland waters.

Management of Global Warming Effects in the European Water Framework Directive: Consideration of Social–Ecological System Features in the Elbe River Basin District

In this study, we examined the extent to which global warming management is currently integrated into the European Water Framework Directive (WFD), the central legal framework for water management in the EU. We focused on the Elbe River Basin District and how global warming is addressed in its water management. We used the social–ecological systems (SES) approach as our theoretical framework, representing an eminent analytical frame of biosphere-based sustainability science. In our study, we analysed core characteristics of SES in the context of global warming to evaluate the effectiveness of current water management in the Elbe River basin concerning long-term changing climate conditions. To determine to what extent each SES feature is considered in the Elbe water management, we applied a scale of 1 to 5. Our results show that the SES feature “scale and openness” is best addressed (score 4.0) by the Elbe River basin management, followed by “context dependency” (score 3.9); however, “non-linearity, uncertainty, unpredictability” (score 3.2), “self-organisation and adaptability” (score 3.1), and “dynamics” (score 3.0) have only moderate impacts. SES features can only be considered comprehensively if global warming is accounted for in an integrated way at a European level. In order to ensure effective implementation, explicit regulations and legally binding obligations are most likely required.

The genome sequence of the European water vole, Arvicola amphibius Linnaeus 1758

We present a genome assembly from an individual male Arvicola amphibius (the European water vole; Chordata; Mammalia; Rodentia; Cricetidae). The genome sequence is 2.30 gigabases in span. The majority of the assembly is scaffolded into 18 chromosomal pseudomolecules, including the X sex chromosome. Gene annotation of this assembly on Ensembl has identified 21,394 protein coding genes.

Suggested Sampling Methodology for Lake Benthic Macroinvertebrates under the Requirements of the European Water Framework Directive

The estimation of the number of samples required for reliably monitoring lakes’ benthic macroinvertebrates is difficult due to the natural variability and cost and time constraints. To determine a statistically robust and effective sampling design, we collected benthic macroinvertebrate samples from 15 Greek natural lakes. We compared the spatial and temporal variability of the benthic macroinvertebrate community composition to identify differences among lakes, between lake zones (sublittoral and profundal) and sampling periods. Furthermore, we examined the sampling precision and determined the number of required samples to attain maximum taxa richness. The diminution of the sampling effort was estimated and the desired precision level, considering different benthic macroinvertebrate abundances, was modelled. No temporal or spatial variation between lake zones was observed in communities’ compositions. The precision of our sampling design was adequate, and rarefaction curves revealed an adequate taxa richness (>70%). The developed model could be applied to assess the required sampling effort in lakes within the Mediterranean ecoregion with similar benthic macroinvertebrate abundances.

Evapotranspiration enhancement drives the European water-budget deficit during multi-year droughts

In a warming climate, periods with below-than-average precipitation will increase in frequency and intensity. During such periods, known as meteorological droughts, sparse but consistent pieces of evidence show that the decline in annual runoff may be proportionally larger than the corresponding decline in precipitation (e.g., −40 % vs. −20 %). Reasons behind this exacerbation of runoff deficit during dry periods remain largely unknown, which challenges generalization at larger scales (i.e., beyond the single catchment), as well as the predictability of when this exacerbation will occur and how intense it will be. Here, we tested the hypothesis that runoff-deficit exacerbation during droughts is a common feature of droughts across climates and is driven by evapotranspiration enhancement. We support this hypothesis by relying on multidecadal records of streamflow and precipitation for more than 200 catchments across various European climates, which distinctively show the emergence of similar periods of exacerbated runoff deficit identified in previous studies, i.e., runoff deficit on the order of −20 % to −40 % less than what expected from precipitation deficit. The magnitude of this exacerbation is two to three times larger for basins located in dry regions than for basins in wet regions and is qualitatively correlated with an increase in annual evapotranspiration during droughts, on the order of 11 % and 33 % over basins characterized by energy- and water-limited evapotranspiration regimes, respectively. Thus, enhanced atmospheric and vegetation demand for moisture during dry periods induces a nonlinear and potentially hysteretic precipitation-runoff relationship for low-flow regimes, which results in an unexpectedly large decrease in runoff during periods of already low water availability. Forecasting onset, magnitude, and duration of these drops in runoff availability has paramount societal implications, especially in a warming climate, given their supporting role for water, food, and energy security. The outcome that water basins are prone to this exacerbation of runoff deficit for various climates and evapotranspiration regimes, compounded by the lack of specific parametrizations of this process in the majority of hydrological and land-surface models, make further understanding of its patterns of predictability an urgent priority for water-resource planning and management in a warming and drier climate.

European environmental governance and the post-ecology perspective: a critical analysis of the Water Framework Directive

In the framework of critical geographies of the environment, this paper discusses European environmental governance and reflects on its policies, practices and discourses. In this context, we analyze the Water Framework Directive (WFD) as a key, ground-breaking policy aimed at reconfiguring European water governance by foregrounding principles of sustainability and participation. By adopting a political ecology approach and the post-ecology analytical perspective, this research analyzes the nature of the WFD with its aims of reconfiguring national water politics in terms of policies, mechanisms and discourses by reflecting on the contradictions and controversies surrounding the directive. Methodologically, the research uses a critical analysis and review of both theoretical and empirical academic literature and policy reports. The paper shows that political ecology, and the post-ecology perspective in particular, can be used to critically reflect on the WFD as a policy oriented towards technocratic governance and participatory arrangements that blur democratic political debate, marginalize conflicts and foster the politics of unsustainability.

Observed exacerbation of the European water-budget deficit during multi-year droughts

<p>In Mediterranean climates, prolonged droughts lead to a significant shift in the precipitation -runoff relationship, usually in the direction of proportionally less precipitation allocated to runoff compared to wet periods. This shift may impact discharge predictions, as many hydrological and land surface models assume that hydrological processes are stationary even under a significant change of the climate (i.e., multi-year droughts) and are generally calibrated with more weight on discharge peaks than low flows. </p><p>Here, we investigate whether multi-year droughts result in a change in the precipitation-runoff relationship over continental European climates (which has never been fully explored before). 30-year records of annual rainfall and runoff from a dataset (>200) of small- and medium-scale (150 to 10000 km2) European catchments were used to test the existence of statistical shifts in the precipitation–runoff relationship. This was achieved by fitting a multivariate regression across annual cumulative full-natural flow, basin-wide annual precipitation, and a categorical variable denoting multi-year drought and non-drought years.</p><p>Results demonstrate that multi-year droughts cause a shift in the precipitation–runoff relationship regardless of predominant climate , with the magnitude of this shift ranging between 20 and 80%. We explore mechanisms of these shifts and potential explanatory factors, including catchment properties and characteristics.</p><p>Understanding changes in the precipitation-runoff relationship is paramount to make models and water resource management more robust to droughts, especially in a warming and more variable climate.</p>