Salt pollution of the middle and lower sections of the river Werra (Germany) and its impact on benthic macroinvertebrates (original) (raw)
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Limnologica - Ecology and Management of Inland Waters, 2011
The reduction and the smoothened amplitudes of the chloride concentrations since 2000 have resulted in a gradual positive development of the aquatic fauna in the River Werra. In the salinized section of the river increasing species numbers have been determined along the salinity gradient, which shows maximum chloride concentrations of about 2500 mg/l, maximum potash concentrations at approximately 200 mg/l, and magnesia concentrations peaked at 320 mg/l. As an immediate consequence of the reduction in salt concentration the immigration of various caddis fly species into the lower River Werra was observed. The Number of taxa per sample rose from 5 to more than 30 in the lower Werra region. Changes in speciesrichness could be seen more frequently in river sections where chloride concentrations fluctuated around 1500 mg/l.
We studied the composition of non-indigenous macroinvertebrate species (NIMS) and biocontamination level in four major large Croatian rivers (the Danube, Sava, Drava and Mura) to establish which environmental parameters are the most important for the composition of NIMS assemblages and to determine how NIMS affect biological metrics regularly used in ecological quality assessment. We sampled benthic macroinvertebrates at 48 sites (44 lotic þ 4 lentic), and among 236 taxa, 21 NIMS were identified, of which 9 were widespread and abundant. Only 14.6% of sites exhibited no biocontamination, 18.7% exhibited low or moderate biocontamination and 66.7% exhibited high or severe biocontamination. Higher biocontamination in the Drava may be due to both the proximity to the Danube as the main source of NIMS and the existence of three large reservoirs. We found significantly negative correlation between the number of NIMS and native taxa. The significant correlations between biocontamination indices and tested biological metrics were as follows: negative with %EPT, EPT-S, BMWP and IBE AQEM, while positive with HR-SI. This indicates that at sites where NIMS are abundant and native taxa scarce, standard biological metrics could provide unreliable results and compromise the assessment of ecological status of large rivers.
Effects of reduced salt concentrations on plant communities in the River Werra (Germany)
Limnologica - Ecology and Management of Inland Waters, 2011
The reduction and equalization of the salt concentrations in the River Werra have resulted in a gradual recovery of the aquatic flora. Spatial high-resolution macrophyte mappings document the spread of the aquatic vascular plants in the middle and lower River Werra. Simultaneously, the plankton blooms have declined. Changes in the composition of the algal communities including diatoms also indicated lower salinity. In addition to the salinity, high nutrient concentrations, waste water discharges and structural degradation are important stressors in the River Werra as shown by e.g. low species richness of vascular plants and the common occurrence of pollution tolerant diatoms. From the existing data it is clear that an encompassing improvement of the ecological conditions in the River Werra can only be achieved by further restoration measures considering all stressors.
Hydrobiologia, 2013
The majority of studies comparing the response of biotic metrics to environmental stress in rivers are based on relatively small, homogeneous datasets resulting from research projects. Here, we used a large dataset from Austrian and German national river monitoring programmes (2,302 sites) to analyse the response of fish, diatom and macroinvertebrate metrics to four stressors acting at different scales (hydromorphology, physico-chemistry, riparian and catchment land use). Nutrient enrichment and catchment land use were the main discriminating stressors for all organism groups, over-ruling the effects of hydromorphological stress on the site scale. The response of fish metrics to stress was generally low, while macroinvertebrate metrics performed best. The Trophic Diatom Index (TDI) responded most strongly to all stressors in the mountain streams, while different metrics were responsive in the lowlands. Our results suggest that many rivers are still considerably affected by nutrient enrichment (eutrophication), which might directly point at implications of catchment land use. We conclude that monitoring datasets are well-suited to detect major broad-scale trends of degradation and their impact on riverine assemblages, while the more subtle effects of local-scale stressors require stream type-specific approaches. Hydrobiologia (2013) 704:389-415 391 Hydromorphology Impoundment
Limnologica - Ecology and Management of Inland Waters, 2004
The present study is based mainly upon the authors' hydrochemical and hydrobiological studies of small silicate streams in South-West Germany, principally in the Black Forest and the Odenwald. The aim of the paper is the adaptation of a practically proven four-level biological classification system of different degrees of acidity using benthic maroinvertebrates to a five-level system of acidification of mainly upland streams with low buffer capacity. The main reason for such a five-class system is the Water Framework Directive of the European Union (EU WFD), which lays down a five-level classification system for the assessment of the ecological quality of waters. The biological method of assessing the state of acidity for evaluation of the degree of anthropogenic acidification under the directive, and principles of the EU WFD, are also described. A list of 278 taxa of the macrozoobenthos has been reclassified from a four-level system to a five-level biological indication system, based upon the authors' scientific expertise and the latest references from literature of different acid sensitive areas in Germany.
Impact of potash mining in streams: the Llobregat basin (northeast Spain) as a case study
Journal of Limnology, 2016
Potash mining is significantly increasing the salt concentration of rivers and streams due to lixiviates coming from the mine tailings. In the present study, we have focused on the middle Llobregat basin (northeast Spain), where an important potash mining activity exists from the beginning of the XX century. Up to 50 million tonnes of saline waste have been disposed in the area, mainly composed of sodium chloride. We assessed the ecological status of streams adjacent to the mines by studying different physicochemical and hydromorphological variables, as well as aquatic macroinvertebrates. We found extraordinary high values of salinity in the studied streams, reaching conductivities up to 132.4 mS/cm. Salt-polluted streams were characterized by a deterioration of the riparian vegetation and the fluvial habitat. Both macroinvertebrate richness and abundance decreased with increasing salinity. In the most polluted stream only two families of macroinvertebrates were found: Ephydridae an...
Hydrobiologia
Salinisation has direct and detrimental physiological effects on freshwater organisms, yet little is known about its indirect effects. Here, we present a study that investigated the primary and secondary effects of salinisation on aquatic macroinvertebrates. We analysed macroinvertebrate samples from nine sites in river Wipper, Germany against nine stressor variables (water quality, salinisation, hydromorphological degradation). A Principal Component Analysis showed water quality deterioration and physical habitat degradation to constitute the main stressor gradients. Two macroinvertebrate community metrics (index of general degradation and percent Ephemeroptera-Plecoptera-Trichoptera specimens) revealed strong and significant positive correlations with water quality, but only weak and insignificant positive correlations with hydromorphological quality. High-resolution temporal measurements revealed notable oxygen deficits at a salinised and macrophyte-rich site that was dominated b...
River Research and Applications, 2019
In this study, the combined effects of hydrological and chemical stressors on benthic macroinvertebrates were evaluated in order to explore the response of the biological community to multiple stressors. The Adige River, located in the south‐eastern Alps, was selected as a case study because representative of the situation of a large river in which the variety of stressors present in the Alpine region act simultaneously. As expected, streamflow showed a seasonal pattern, with high flows in the spring–summer period; however, locally, the natural hydrological regime was altered by the presence of hydropower systems, which chiefly affected low flows. Multivariate analysis showed seasonal and spatial patterns in both chemical and hydrological parameters with a clear gradient in the concentration of nitrate, personal care, and pharmaceutical products moving from headwaters to the main stem of the river. The macroinvertebrate community composition was significantly different in summer and...
Water, Air, & Soil Pollution, 2019
The anthropogenic salinisation of rivers causes grave environmental problems that are responsible for the degradation of water quality on a worldwide scale as well as for biological changes in aquatic ecosystems. The objectives of the survey were to analyse the structure of the macroinvertebrate communities in the Bolina River, which is currently the second most anthropogenic salinised river in the world, in relation to various types of instream microhabitats and to determine the environmental factors that have a significant effect on the structure of the macroinvertebrate communities. The result of a canonical correspondence analysis (CCA) showed that electrical conductivity, the temperature of the water and the organic matter content in the bottom sediments were the most important factors (statistically significant) that influenced the macroinvertebrate communities in the anthropogenic salinised river. A total of 77 taxa of macroinvertebrates were recorded in the Bolina River. A Kruskal-Wallis one-way ANOVA and multiple comparison post hoc tests revealed statistically significant differences in the median number of taxa and the median density of macroinvertebrates between the various types of microhabitats in the salinised river. The anthropogenic salinisation of a river can lead to a decrease in aquatic biodiversity that favours invasive species over native species. The Bolina River, which has a salinity of up to 33.6‰, is an example of a unique habitat for organisms that are salt tolerant (euryhaline) or eurytopic. It is a route for the spread of alien and invasive invertebrate species including Gammarus tigrinus, Potamopyrgus antipodarum, and Monopylephorus limosus.