The Use of Phytoplankton in the Assessment of Water Quality in the Lower Section of Poland’s Largest River

Phytoplankton studies were carried out in the lower course of Poland’s largest river, the Vistula. This section of the Vistula has changed much since the 19th century due to regulation of the bed and limitation of its flood banks. In the years 1994–2020, hydrobiological studies of physical and chemical parameters and phytoplankton were carried out. On the basis of these studies, this research investigated the water quality of the river. Since 2000, a gradual improvement in water quality in the river has been observed, as manifested by decreasing phytoplankton biomass (from over 15 mg/L in 1994 and 2003 to less than 10 mg/L in the 2000s) and lower chlorophyll a concentrations (from 48 µg/L in 1998 to 12.5 µg/L in 2020). The river’s ecological potential index, calculated on the basis of indicator species of phytoplankton and chlorophyll a concentration, also indicates a progressive improvement. In the 1990s, the ecological potential was poor; at the turn of the century, it was moderate; and in the following years, the phytoplankton studies showed an ecological potential that was good or moderate (slightly below the lower threshold of good potential).

Can zooplankton species be used as indicators of trophic status and ecological potential of reservoirs?

The European Water Framework Directive implements the policies to achieve a good ecological status of all European waterbodies. To determine the ecological potential in freshwater environments, abiotic (morphology, physical and chemical variables) and biotics (algae, fishes, etc.) metrics are used. Despite their importance in trophic web, zooplankton was not included as one of the Biological Quality Elements (BQE) to determine the water quality. In the present research, we studied the zooplankton species that can be considered as indicators of trophic status and ecological potential for more than 60 water reservoirs. The data were obtained from more of 300 samples collected during 10 years from reservoirs at Ebro River watershed, which is the largest basin in Spain. According to their physicochemical and biological elements, the trophic status and ecological potential of these reservoirs were established. More than 150 zooplankton species were identified during the study. The results from this research indicate that species that are related with low water quality are: Acanthocyclops americanus, Ceriodaphnia spp., Daphnia cucullata, Daphnia párvula, Diaphanosoma brachyurum, Brachionus angularis, Keratella cochlearis and Phompolyx sulcata. An indicator of moderate quality was Bosmina longirostris, while Daphnia longispina, Ascomorpha ovalis and Ascomorpha saltans were considered as indicators of good water quality. The data obtained suggest that zooplankton species can be used as a valuable tool to determine the water quality status and should be considered, in a near future, as one more of the BQE within the WFD metrics.

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.

A new charophyte habitat with a stabilized good ecological potential of mine water

Each newly-created pond which is supplied with mine water gives the opportunity to study a unique ecosystem in context of possible conditions for biotic live. Therefore, this research aimed to assess a phytoplankton-based ecological potential against the trophic conditions and the risk of contamination with trace elements, and demonstrate the possibility to stabilize at least good water quality of a clarification pond. The gradual decrease in turbidity-related variables (including suspended solids and iron) and nutrients, on the one hand, and an increase in phytoplankton-related indicators, on the other hand, were the most evident. Besides, relative stability in trace elements (the best water quality class), trophic level (slightly eutrophic level) and ecological potential (maximum potential), and relative instability in sulfates and calcium were also recorded. The final stabilization of water habitat resulted in abundant growth of charophyte Nitella mucronata. This all suggested a new ecological opportunity for settlement of a rare species and important for biodiversity enhancement. Furthermore, the study revealed that a clarification pond did not pose any toxic risk from the elevated content of trace elements or the growth of toxic or potentially toxic cyanobacteria which is essential for proper functioning and management of water ecosystems.

Assessment of the ecological potential of the region using the method of regression analysis and the coefficient of elasticity for sustainable development

One of the fundamental economic determinants of sustainable development is the optimal use of limited resources and the use of environmentally friendly-nature, energy, and material-saving technologies, including the extraction and processing of raw materials, the creation of environmentally friendly products, minimization, processing and disposal of waste. In this study, in order to clarify the indicator "ecological potential of the region", it is proposed to consider a number of indica-tors that, according to the authors, have a significant impact on this phenomenon. One of the significant indicators for assessing the ecological potential of the territo-ry is the indicator of the area of landfills for the disposal of solid municipal waste (MSW) in a particular region. The authors hypothesize that the change in the vol-umes of landfills for the disposal of solid municipal waste (MSW) in a particular region depends on the type of development of the territory. As the main defining indicators (factors-arguments) of the development of the region were chosen: the number of manufacturing enterprises, population and gross regional product (GRP) per capita. The authors have developed a regression model to determine the degree of influence of a number of socio-economic indicators on the volumes of landfills for the disposal of MSW. Significant parameters were determined for terri-tories with different types of regional development (extensive type of develop-ment. Using the method of regression analysis, it was found by calculation that for regions of all types of development, the decisive factor that affects the volume of landfills for the disposal of MSW is the population of the territory. With the help of the coefficient of elasticity, the closeness of the relationship of the considered fac-tors-arguments was determined.

‘Terres vaines et vagues’: Ecocriticism and Breton Wastelands in Visual and Literary Representation

Despite their long histories as a culturally valuable commons and sites of biodiversity, the Breton landes were frequently depicted by nineteenth-century authors, travellers and administrators as wild, unproductive wastelands. While the architects of France's ‘interior colonization’ identified such areas as an ugly, infertile expanse to be cleared and put to use, many visual artists were producing a compelling counter-narrative, representing the landes and zones humides as places of beauty and reverie. This article examines the work of artists such as François Blin, Camille Bernier, Alexandre Ségé and Henri Rivière from an ecocritical perspective, arguing that their work contributed to a discourse of preservation by encouraging new ways of seeing the land, not for its extractive utility but as a space of unexpected splendour and enchantment. Far from a regressive form of nostalgia, these images encourage a unique ‘dwelling perspective’ which uses aesthetic beauty to reveal the area's ecological potential and to articulate a call for responsible environmental stewardship.