Ecohydrology & Hydrobiology最新文献

Researchers have increasingly integrated machine learning (ML) and deep learning (DL) algorithms to forecast the risk, vulnerability, and susceptibility of various geo-environmental challenges. However, to the best of our knowledge, there is a dearth of studies that have employed DL to predict the health status of wetland habitats, and none have explored a comparative analysis between ML and DL models in this context. This study aims to fill this gap by focusing on the development of wetland habitat health status using both ML and DL models, seeking to determine whether DL models exhibit superior predictability compared to ML models. The assessment of wetland habitat health status reveals that smaller fringe wetlands situated away from main rivers tend to be identified as poor habitats. The transition from phase II to III is marked by a substantial reduction in wetland area, decreasing from 438.76 km² to 235.68 km² across different habitat zones, underscoring the significant loss of wetland areas. The observed 43–46 % decline in very poor and poor habitat areas from phase II to III lends credibility to the predictive capabilities of the models. Notably, among the applied ML and DL models, XGB from the ML category and DNB from the DL category have demonstrated superior performance. In all instances, DL models outperformed ML models, suggesting that deep learning algorithms hold promise for evaluating wetland habitat health status. The mapping and modelling of wetland habitat health status at a spatial scale are pivotal for formulating effective wetland management strategies. The identification of areas with poor and good habitat health provides valuable information for prioritized planning and targeted wetland restoration efforts.

Microbial contamination of water, as well as the development of biofilm in irrigation systems, is one of the factors contributing to water losses, leading to a decrease in the optimization of the irrigation process and, consequently, a decrease in plant production. Water shortages are a highly undesirable phenomenon, particularly within the context of anthropogenic climate changes and the constraint of potable water resources. Biofilm can also be a reservoir of pathogenic microorganisms for human health, animal welfare, and plant production. Contaminated water used to irrigate vegetables that do not require heat treatment can lead to pathogen propagation, causing disease outbreaks. Therefore, it is essential to understand the dynamics of biofilm development and its underlying mechanisms, as well as its relation to water quality, to develop strategies that could help reduce or prevent biofilm formation and its negative effects. The analysis of factors promoting the development and composition of biofilm in irrigation systems allows the implementation of the most effective preventive methods, which translate into the optimization of the irrigation process and plant production. This paper aims to analyze reports related to the formation and microbial composition of biofilms occurring in agricultural irrigation systems, as well as to present the risks associated with biofilm formation and methods for its eradication. This review summarizes reports related to the various factors influencing biofilm formation and irrigation water quality, which may be a prelude to a comprehensive assessment and formulation of guidelines related to the management of water-based irrigation systems to improve biosafety.

This study analysed the formation of biofilms in the drinking water distribution system in Wroclaw. The focus was on the influence of the material from which pipes in water distribution systems are built: polyethylene (PE) and polypropylene (PP). Two reactors with continuous water flow were used. Once the quasi- steady state was determined, an analysis was carried out to measure the total number of microorganisms per unit volume, which were stabilised without affecting further changes in concentration, and to study the basic physicochemical parameters of water that can affect the microbial growth that forms. In addition, a literature review was conducted to analyse biofilm formation based on physicochemical parameters in the water distribution system. Psychrophilic bacteria were shown to be more numerous than mesophilic bacteria, with the growth rate of the latter being higher. An increase in the number of microorganisms was observed, with higher concentrations found on PE surfaces because the rougher surface structure provides better adhesion for biofilm-forming microorganisms than on a surface made of polypropylene (PP). The presence of mesophilic bacteria may indicate the potential for pathogenic microorganisms, as well as the formation of a primary biofilm characterised by irreversible attachment to the substrate. These findings suggest that synthetic materials such as PE are more susceptible to biological growth than polypropylene (PP) as a result of their uneven surface structure, which facilitates the deposition of biofilm-forming organisms. The preliminary results can be used as an important reference for future research related to biofilms in drinking water distribution systems.

The presence of microplastics (MP) in the organs of five fish species caught in the freshwater reservoirs of northern Poland was evaluated. Gills, liver, and digestive tracts of several commercial fish species such as common perch, silver Prussian carp, roach, and rainbow trout were tested to assess MP uptake due to their high population size as well as they play significant role as biomonitors. Since the mentioned species are gladly consumed they can be considered as a source of MP for humans. MP items were identified in all fish species. The highest contribution of MP was observed in predatory fish such as rainbow trout and perch. None of the correlations between MP abundance and fish body size. The number of items per individual fish ranged from 1 to 12, with an average of 1.78. Among the investigated MP shapes two types were found: fibers (56 %) and particles (44 %). MP were observed in different organs, such as the gills (50 %), liver (11 %), and digestive tract (39 %). The most dominant color observed was blue (58 %). The dominant size range was 1–5 mm (42 %), and 0.1–0.5 mm (42 %) respectively. The FT-IR characterization revealed the presence of polymers predominantly containing polyethylene, polypropylene, polyacrylic acid, cellophane, and polystyrene.

Ever-new cyanotoxins are being discovered, with planktic Cyanobacteria being the most studied communities, although records of cyanotoxins from benthic communities are becoming increasingly common. ​​Thus, the latter also started threatening users of water for recreational or drinking purposes. However, vast areas of the globe, i.a. Central Asia, are still understudied in this respect. Our recent study of benthic Cyanobacteria in the mountains of Eastern Pamir (Tajikistan) suggested that cyanotoxin production in high mountain environments is very limited. Here we present further study of Cyanobacteria, cyanotoxins, and other biologically active compounds such as geosmin and 2-Methylisoborneol (MIB) in microbial mats and water above them. Samples were collected in Eastern Pamirs, in UV (7–11) and altitude gradient (1000–4000 m a.s.l.). In the study, we used microscopic and genetic identification of Cyanobacteria based on NGS of V3-V4 16S rRNA amplicon and toxin assays using LC-QTOF-MS. The analyses demonstrated that the studied microbial mats contained potentially toxic Cyanobacteria (Anabaena, Lyngbya, Nostoc, Oscillatoria, and Phormidium). The production of cyanotoxins and taste and odor compounds (T&O) in natural environments was restricted to altitudes up to 3000 m a.s.l. Three water samples at 1000, 2000 and 3000 m a.s.l. contained MIB and/or geosmin, while debromoaplysiatoxin was noted at 2000 m a.s.l. Additionally, two strains (Hillbrichtia pamiria gen. nov. sp. nov. and Nostoc paludosum) isolated from sites at about 4000 m, in which no cyanotoxins or T&O were identified, produced debromoaplysiatoxin and microginin in laboratory conditions. The results suggest that in a stressful environment Cyanobacteria do not produce toxins.

Beaver-created ponds constitute an important element of small water retention in forest catchments and preserving biodiversity as breeding sites for vertebrates and invertebrates. In many areas, these habitats disappear as a result of drainage melioration, drainage formed from agricultural and developmental needs, and liquidation by littering and backfilling. This study was carried out from 2017 to 2019 to understand the transformations of river valley as a result of the beaver activity in the context of newly created ponds and mountain stream and to assess the changes and biodiversity. Beavers modified in-stream habitat by constructing dams, thus creating a series of interconnected dam ponds. Organic matter retention was higher in beaver ponds relative to unmodified river section. In beaver ponds, the invertebrate aquatic assemblages was highly variable. A total of 56 taxa were identified, and significant seasonal variability of benthos assemblages. The values of diversity indices confirmed the instability of benthos assemblage in beaver ponds (variability of species amongst years and sites), which may be related to the short period of their existence. Lotic macroinvertebrate assemblages were common in the beaver-modified section of stream, with some lentic taxa also being present. The unmodified section of stream had more abundant collectors- gatherers and predators and no filter feeders, while scrapers were more abundant in modified section. The environmental variables which significantly influenced invertebrate occurrence were pH, nitrates, iron and the content of organic matter. The results contribute to ecological characteristics of these aquatic environments, and enable determining their functioning in forest areas.