Phytoplankton based assessment of the ecological status of four shallow lakes (Eastern Poland) according to Water Framework Directive – a comparison of approaches

AbstractThe EU Water Framework Directive includes phytoplankton as one of the four biological elements to be used in the assessment of the ecological status of surface waters. In this work we establish the ecological status of four shallow lakes in the Polesie Region of Eastern Poland on the basis of phytoplankton and physicochemical data from the lake water. A number of recently developed phytoplankton indices, including the Carlson Index, Q index and German PSI were compared. Cyanoprokaryota, chlorophytes and dinophytes dominated in Lakes Głębokie and Sumin, while in the Lakes Rotcze and Maśluchowskie the biggest share belonged to Chlorophyta. On the basis of the Carlson Index, Lake Głębokie had the highest trophic score, while the lowest score was for Lake Rotcze. A similar result was also found with the Q index which indicated a good ecological state for Lake Rotcze (Q=3.5), a bad state for Lake Głębokie (Q=0.9), a poor status for Lake Sumin (Q=1.2) and a moderate status for Lake Maśluchowskie (Q=2.9). Similar results were obtained with the use of the German PSI which classified Lake Głębokie as bad status (PSI=4.7) and Lake Rotcze as good (PSI=2), although differences between the 2 indices appeared between the moderate and poor status lakes (respectively in the case of Lake Sumin – PSI=2.6 and Lake Maśluchowskie – PSI=4.4)

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe

Effects of multiple stressors on cyanobacteria abundance vary with lake type

Blooms of cyanobacteria are a current threat to global water security that is expected to increase in the future because of increasing nutrient enrichment, increasing temperature and extreme precipitation in combination with prolonged drought. However, the responses to multiple stressors, such as those above, are often complex and there is contradictory evidence as to how they may interact. Here we used broad scale data from 494 lakes in central and northern Europe, to assess how cyanobacteria respond to nutrients (phosphorus), temperature and water retention time in different types of lakes. Eight lake types were examined based on factorial combinations of major factors that determine phytoplankton composition and sensitivity to nutrients: alkalinity (low and medium‐high), colour (clear and humic) and mixing intensity (polymictic and stratified). In line with expectations, cyanobacteria increased with temperature and retention time in five of the eight lake types. Temperature effects were greatest in lake types situated at higher latitudes, suggesting that lakes currently not at risk could be affected by warming in the future. However, the sensitivity of cyanobacteria to temperature, retention time and phosphorus varied among lake types highlighting the complex responses of lakes to multiple stressors. For example, in polymictic, medium‐high alkalinity, humic lakes cyanobacteria biovolume was positively explained by retention time and a synergy between TP and temperature while in polymictic, medium‐high alkalinity, clear lakes only retention time was identified as an explanatory variable. These results show that, although climate change will need to be accounted for when managing the risk of cyanobacteria in lakes, a ‘one‐size fits‐all’ approach is not appropriate. When forecasting the response of cyanobacteria to future environmental change, including changes caused by climate and local management, it will be important to take this differential sensitivity of lakes into account

Phytoplankton in the ecological status assessment of European lakes – advantages and constraints

Although the phytoplankton indices describing the response of phytoplankton to the eutrophication have been developed and used for many years in the routine lake monitoring programme in some countries, the implementation of the Water Framework Directive (WFD) [EC, 2000] stimulated the development and improvement of quite a number of the current WFD-compliant phytoplankton-based methods. This paper is a review of the current phytoplankton-based methods for assessing the ecological status of European lakes. The particular attention was paid to the ways of solving problems arising from the need to reflect the complex and dynamic plankton algal communities on a numerical scale in order to gain reliable information about the state of the ecosystem

Functional urban areas and the development of small towns (on the example of FUA Malbork and Sztum town)

Artykuł poświęcony jest analizie Strategii Rozwoju Miejskiego Obszaru Funkcjonalnego Malborka na lata 2014-2020, która przeprowadzona została z punktu widzenia miasta Sztum – jednego z partnerów realizujących strategię. W pierwszej części nakreślono ramy opracowywania strategii MOF. Opisano przesłanki merytoryczne służące do wyznaczania obszarów funkcjonalnych oraz scharakteryzowano instrumentarium adresowane do realizacji MOF-ów, jakim są Zintegrowane Inwestycje Terytorialne (w przypadku województwa pomorskiego – Zintegrowane Porozumienia Terytorialne). Część aplikacyjna zawiera opis Sztumu podkreślający jego specyfikę jako małego miasta, przedstawia MOF Malborka i jego priorytety z punktu widzenia znaczenia dla Sztumu. Zawarto w niej przykłady projektów strategicznych, w które bezpośrednio zaangażowane jest miasto, a których oddziaływanie przyczyni się do intensyfikacji jego rozwoju. Zaprezentowane badania, biorąc pod uwagę kontekst i cel artykułu, mają charakter idiograficzny, dla których właściwą procedurą badawczą jest analiza studium przypadków (case study).The article is devoted to analysis of the Development Strategy of Malbork Functional Area (FUA) for the years 2014-2020, which was carried out from the perspective of the Sztum town - one of the seven Partners implementing Strategy. The first part presents a framework for FUA strategies. Described the essential reasons for setting the functional areas and characterized instruments aimed at the implementation of the FUA, which are Integrated Territorial Investment - ITI (in the case of the Pomeranian Integrated Territorial Agreement). The application part contains a description of Sztum emphasizing its specificity as a small town, shows the MOF Malbork and its priorities from the viewpoint of importance for Sztum. It describes examples of strategic projects. It describes examples of strategic projects, in which the town is directly involved and whose the impact will intensify the development of the town

Rapid monitoring of cyanobacteria in lakes – a case study in the Wel River catchment, Poland

The purpose of the study was to ascertain the effect of cyanobacterial abundance and its taxonomic structure on the results of measurements made by a fluorometric device designed to detect in situ chlorophyll a and phycocyanin. A multiparameter water quality probe was tested at 10 lakes located in the Wel River catchment. We found a strong correlation between the chlorophyll a concentration determined by laboratory procedure (CHL-a) and that obtained as a result of the probe measurements (YSI CHL-a) (R=0.78) as well as between the YSI CHL-a and the total phytoplankton biomass (R=0.73), whereas YSI CHL-a was not a good predictor of cyanobacterial biomass (R=0.24). The phycocyanin recorded by the probe was proportional to the total biomass of cyanobacteria (R=0.86); however, this cyanobacterial taxonomic structure influenced the fluorometric signal. Nevertheless, our study showed significant differentiation of phycocyanin measurement distribution at different levels of cyanobacterial abundance (10 mg L−1), which indicates that the PC-YSI measurements are valuable in the detection of increased risk of exceeding health alert thresholds recommended by the WHO

Phytoplankton indicator taxa for reference conditions in Northern and Central European lowland lakes

Phytoplankton data from 606 lakes were used to characterize indicator taxa of near-pristine reference conditions in clearwater and humic lowland lakes of Northern and Central Europe. Reference lakes were selected based on low pressure from catchment land-use, low population density and the absence of point sources. Reference lakes had low phytoplankton biomass and taxa richness compared to non-reference lakes. In low alkalinity lakes of Northern Europe, the reference communities had high biomass proportions of chrysophytes and low proportions of cyanobacteria; in the Central European high alkalinity lakes, the biomass was distributed more evenly among algal groups. Indicator species analysis and similarity analysis listed 5-29 taxa indicating reference conditions. Indicator taxa differed especially between the low alkalinity and the high alkalinity lakes, but there were also country-specific differences. Most common indicator taxa for the northern reference lakes were chrysophytes (e.g. Bitrichia, Dinobryon). In the Central European reference lakes, diatoms (e.g. Cyclotella) were more characteristic. Despite the differences, there was a general finding that taxa present in reference lakes were often also present in non-reference lakes, but typically in lower biomass proportions; another characteristic of the reference communities is the absence of many taxa typically found in non-reference lakes

Phytoplankton indicator taxa for reference conditions in lowland Northern and Central European lakes

Phytoplankton data from 606 lakes was used to characterise indicator taxa of near pristine reference conditions in clearwater and humic lowland lakes in Northern and Central Europe. Reference lakes were selected based on low pressure from catchment land-use, low population density and absence of point sources. Reference lakes had low phytoplankton biomass and taxa richness compared to non-reference lakes. In the North European low alkalinitry lakes the reference communities had high biomass proportions of chrysophytes and low proportions of cyanobacteria; in the Central European high alkalinity lakes the biomass was distributed more evenly among algal groups. Indicator Species Analysis and Similarity Analysis listed 5-29 taxa for reference conditions. Indicator taxa differed especially between the low alkalinity North European and high alkalinity Central European lakess but there were also country-specific differences. Most common indicator taxa for the Northern reference lakes were chrysophytes (e.g. Bitrichia, Dinobryon). In the Central European reference lakes diatoms (e.g. Cyclotella) were more characteristic. Despite the differences there was a general finding that taxa present in reference lakes were often also present in non-reference lakes, but typically in lower biomass proportions. Another characteristic of the reference communities is the absence of many taxa typically found in non-reference lakes.JRC.H.1-Water Resource

Strength and uncertainty of lake phytoplankton metrics for assessing eutrophication impacts in lakes.

Phytoplankton constitutes a diverse array of short-lived organisms which derive their nutrients from the water column of lakes. These features make this community the most direct and earliest indicator of the impacts of changing nutrient conditions on lake ecosystems. It also makes them particularly suitable for measuring the success of restoration measures following reduction in nutrient loads. This paper integrates a large volume of work on a number of measures, or metrics, developed or using phytoplankton to assess the ecological status of European lakes, as required for the Water Framework Directive (WFD). It examines the indicator strenght of these metrics, specifically in relation to representing the impacts of eutrophication. It also examines how these measures vary naturally at different locations within a lake, as well as between lakes, and how much variability is associated with different replicate samples, different months within a year and between years. On the basis of this analysis, three of the strongest metrics (chlorophyll-a, Phytoplankton Trophic Index (PTI) and cyanobacterial biovolume) are recommended for use as robust measures for assessing the ecological quality of lakes in relation to nutrient enrichment pressures and a minimum recommended sampling frequency is provided for these three metrics.JRC.H.1-Water Resource

Quantifying uncertainties in biologically-based water quality assessment: a pan-European analysis of lake phytoplankton community metrics

Lake phytoplankton are adopted world-wide as a sensitive indicator of water quality. European environmental legislation, the EU Water Framework Directive (WFD), formalises this, requiring the use of phytoplankton to assess the ecological status of lakes and coastal waters. Here we provide a rigorous assessment of a number of proposed phytoplankton metrics for assessing the ecological quality of European lakes, specifically in response to nutrient enrichment, or eutrophication, the most widespread pressure affecting lakes. To be useful indicators, metrics must have a small measurement error relative to the eutrophication signal we want them to represent among lakes of different nutrient status. An understanding of variability in metric scores among different locations around a lake, or due to sampling and analytical variability can also identify how best this measurement error is minimised. To quantify metric variability, we analyse data from a multi-scale field campaign of 32 European lakes, resolving the extent to which seven phytoplankton metrics (including chlorophyll a, the most widely used metric of lake quality) vary among lakes, among sampling locations within a lake and through sample replication and processing. We also relate these metrics to environmental variables, including total phosphorus concentration as an indicator of eutrophication. For all seven metrics, 65–96% of the variance in metric scores was among lakes, much higher than variability occurring due to sampling/sample processing. Using multi-model inference, there was strong support for relationships between among-lake variation in three metrics and differences in total phosphorus concentrations. Three of the metrics were also related to mean lake depth. Variability among locations within a lake was minimal (<4%), with sub-samples and analysts accounting for much of the within-lake metric variance. This indicates that a single sampling location is representative and suggests that sub-sample replication and standardisation of analyst procedures should result in increased precision of ecological assessments based upon these metrics. For three phytoplankton metrics being used in the WFD: chlorophyll a concentration, the Phytoplankton Trophic Index (PTI) and cyanobacterial biovolume, >85% of the variance in metric scores was among-lakes and total phosphorus concentration was well supported as a predictor of this variation. Based upon this study, we can recommend that these three proposed metrics can be considered sufficiently robust for the ecological status assessment of European lakes in WFD monitoring schemes