We begin our current review of the water literature with a series of papers on threats to water status. Eutrophication, salinization or new types of pollution are constant pressures on ecosystems and an ongoing and unfortunately growing problem. We must also not forget about hydromorphological transformations. Studies indicate that they affect river watersheds and ice cover parameters. We also present a paper on new challenges in drought forecasting.
1. water quality deterioration remains a major stressor for macroinvertebrate, diatom and fish communities in German rivers
Markert N., Guhl B., Feld Ch. K., (2023). Water quality deterioration remains a major stressor for macroinvertebrate, diatom and fish communities in German rivers. Science Of The Total Environment, 907, 167994.
According to reports from the European Environment Agency (EEA), there are still about 60 percent. rivers in Europe do not meet quality standards for biological elements, i.e. the condition of the communities of organisms that inhabit them. The problem was addressed by researchers in Germany, who asked how the effects of different stressors on different groups of aquatic organisms differ depending on their sensitivity to a particular pressure. Based on river monitoring data from four German states and using Random Forest (RF) analysis, the authors examined the effects of 19 variables from 6 stressor groups (nutrients, salt ions, water temperature, dissolved oxygen, a mixture of 51 micropollutants, hydrological changes and morphological habitat quality) on 3 biological communities – benthic diatoms, benthic macroinvertebrates and fish. It turned out that the responses of all communities were explained primarily by factors related to water quality, but not by chemical micropollutants. In contrast, the impact of physical pressures was less pronounced, being stronger for hydrological than for morphological changes. Despite the inclusion of various types of pressures, the decline in water quality remains a major cause of the inadequate condition of aquatic ecosystems. The authors conclude that to achieve good ecological status, river restoration and management must address both water quality and hydromorphological stressors. Restricting analyses to only one group of organisms (e.g., macroinvertebrates) or to only selected indicators can make it difficult to identify stressors and classify them hierarchically, thereby misleading river managers.
Kaushal S.S., Likens G.E., Mayer P.M. et al. (2023). The anthropogenic salt cycle. Nat Rev Earth Environ.
One of the most significant pressures on water, which is unfortunately growing in importance globally, is salinity. We have written about this problem more than once in Water Matters. A few days ago, the journal Nature Reviews Earth & Environment published a review article with the very telling title “The Anthropogenic Salt Cycle” (oryg. “The anthropogenic salt cycle”; until the association with the anthropogenic water cycle itself comes to mind!). A team of scientists from several U.S. research centers analyzed, based on a review of the literature, changes in nature’s natural salt cycle, concentrations and circulation pathways in the face of increasing global trends in salt production. The natural circulation of salt is mainly conditioned by relatively slow geological and hydrological processes. The increasing production and use of salt is altering the natural ionic balance of many Earth systems, and one of the most serious effects of this process is the so-called “salt balance. freshwater salinization syndrome (we wrote about this syndrome, as well as when freshwater is too salty, in Water Matters). As cited by the authors, global production of various salts has increased rapidly over the past century, reaching a volume of about 300 Mt NaCl per year. Excess salt spreads through the anthropogenic salt cycle, causing freshwater salinization with all its consequences for the ecosystem, but also negatively affecting food and energy production, air quality, human health and infrastructure. The authors make clear the urgent need to set environmental standards and thresholds for salt ion concentrations, as well as to reduce water salinity, before serious and irreversible damage is done to the environment.
The article was unfortunately published without open access, but I assure anyone interested in the topic that it is worth the effort to obtain it.
3. A bibliometric analysis of emerging contaminants (ECs) (2001-2021): Evolution of hotspots and research trends
Yu Yang, Wang Siyu, Yu Pingfeng et al, (2024). A bibliometric analysis of emerging contaminants (ECs) (2001-2021): Evolution of hotspots and research trends. Science of The Total Environment, 907, 168116.
Another article, which does not offer open access, but explores the very relevant and topical problem of water pollution, is a paper by Chinese researchers addressing the issue of so-called “water pollution. emerging contaminants(EC, or emerging contaminants). EC, also known as contaminants of emerging concern(CEC, or contaminants of emerging concern), is the term used for pollutants that may affect the environment or human health, but are usually not regulated by existing environmental regulations. The authors of the article asked themselves how the trends and directions of scientific research in the field of individual ECs have changed over the past two decades. Based on a review of nearly 8,000. papers published between 2001 and 2021 demonstrate that antibiotics, microplastics, endocrine disrupting compounds (EDCs), per- and polyfluoroalkyl compounds (PFASs), pesticides, heavy metals and nanoparticles are attracting increasing scientific attention. In contrast, research interest in conventional pharmaceuticals, persistent organic pollutants and substances such as benzotriazole, diclofenac, bisphenol A, carbamazepine, triclosan and titanium dioxide is clearly declining. The authors identify PFAS and EDCs as potentially key EC research sites in the coming years. This paper presents an objective and comprehensive insight into the map of EC research, which can be used to indicate future research directions in this field.
Shyrokaya A., Pappenberger F., Pechlivanidis I. et al. (2023). Advances and gaps in the science and practice of impact-based forecasting of droughts. WIREs Water, e1698.
The effectiveness of measures aimed at improving the health of aquatic ecosystems is certainly significantly affected by climate change and the growing risk of drought. Developments in digital weather modeling and forecasting techniques are making it possible to predict drought and monitor it with increasing accuracy. However, the drought early warning systems currently in use are based on statistical indicators that do not take into account regional specificities, so they do not take into account the socio-economic impact of the phenomenon. The solution to this problem, which is increasingly being advocated and applied, is to move away from conventional physical drought forecasting and use impact-based forecasting(IbF). The issue was taken up by a team of Swedish researchers who conducted a comprehensive review of the IbF issue, outlining the progress made in the field over the past 10 years. The authors identify seven scientific and practical challenges/limitations to the use of IbF and propose actions to address them. The purpose of the article is to advance the field of drought impact forecasting and its use in making informed decisions on drought mitigation and minimization efforts around the world.
5 River Habitat Survey: Does This Help to Explain the Nature of Water Mite (Acari and Hydrachnidia) Assemblages?
Stryjecki R.; Peši´c V., Szlauer-Lukaszewska A. et al, (2023). River Habitat Survey: Does This Help to Explain the Nature of Water Mite (Acari and Hydrachnidia) Assemblages? Water, 15, 3751.
Readers interested in environmental assessment methodologies may be interested in the work of a team of mainly Polish scientists (with the participation also of researchers from Montenegro and India) from several research centers, on the possibility of applying a protocol for assessing the state of hydromorphological transformation of rivers using the Lake Habitat Survey(LHS) method to predict aquatic communities (Acari, Hydrachnidia). Water assessments in accordance with EU legislation are based on the links between the state of abiotic (including hydromorphological) conditions of aquatic ecosystems and the condition of biological communities. The authors of this study tested whether the hydromorphological characteristics of river habitats are an important element in explaining the characteristics of water mite communities and whether the RHS method can be used to predict the characteristics of Hydrachnidia populations in rivers. Based on a detailed study of the LHS method and mite communities at six study sites located on the Krąpiel River in northwestern Poland (West Pomeranian Voivodeship), the authors showed that the LHS method indicators explained the river’s water mite communities at the level of general population parameters, i.e. The number of individuals and species (species richness). In contrast, clarifying the taxonomic structure of waterbirds requires using more detailed habitat characteristics at the local level (microhabitats). The work indicates the potential of water mites as indicators of physical transformation of the aquatic environment.
Fukś M. (2023). Changes in river ice cover in the context of climate change and dam impacts: a review. Aquat Sci, 85, 113.
And finally, the problem of hydromorphological transformation of rivers with a winter accent, that is, how climate change and the operation of dam reservoirs affect the characteristics of river ice cover. This issue was analyzed by a scientist from the Institute of Geography and Spatial Planning of the Polish Academy of Sciences in Krakow, Maksymilian Fukś, and his results were published in the autumn issue of the journal Aquatic Sciences. Based on a review of the literature, the author analyzed the parameters of river ice cover, such as freezing time, onset of breakup, duration and thickness, and the analysis mainly included works that studied the variability of these parameters based on long measurement cycles (>1 year). Its results indicate that the main reason for the disruption of river ice cover observed since the early 20th century. are the effects of climate change, which have contributed to a reduction in the duration of ice cover on rivers. This phenomenon occurs mainly as a result of its earlier decay, rather than its later formation. As a result of changes in the timing of the freezing and disintegration of river ice cover, the duration of ice cover is shortening by up to several days per decade. A decrease in ice thickness was also observed in most of the areas studied. In addition, the results of measurements from water gauge stations and modeling studies have shown that the trends of ice cover freezing and breakup are less spatially variable in Eurasia than in North America. Analysis of the impact of dam reservoirs has shown that they can significantly affect the spatio-temporal distribution of ice cover occurrence on rivers even on a global scale. Studies of individual reservoirs indicate that their impact on local ice cover is significant, and the range of impact can reach several hundred kilometers. The role of reservoirs in the occurrence of ice cover on a regional and global scale is not known, but the rationale presented by the author suggests that it may be significant, especially in central North America, Europe and East Asia.
The author stresses the need to study changes in river ice cover based on remote sensing data. Such studies will provide insight into the temporal and spatial distribution of trends in river ice cover parameters and the strength and extent of the impact of dam reservoirs.