Ecohydrology & Hydrobiology最新文献

Water resources sustainability is an increasing concern, requiring accurate estimates of the hydrological processes involved. This study evaluates the impacts of climate change (CC) and land use (LU) in a river basin in the Brazilian semi-arid. Using the Soil & Water Assessment Tool (SWAT), calibration/ validation was carried out based on limited measurements for discharge and using complementary remote sensing information for evapotranspiration (ET), as well as experimental data for soil moisture (SM). The evapotranspiration data used for calibration were obtained from the MOD16A2 product, at sub-basin scale. Principal component analysis was used to evaluate the interaction between variables. To assess the impacts of CC e and LU two scenarios were investigated: S1 – LU map without insertion of Permanent Preservation Areas (PPA), and S2 – with insertion of PPA. The Regional Climate Models (RCM) Eta-MIROC5 and Eta-HADGEM-ES for the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios were adopted. The SWAT model adequately represented evapotranspiration, with Nash-Sutcliffe coefficient (NS) of 0.67 for calibration, and 0.74 for validation. For wet periods, the SM simulated values were similar to the experimental measurements with a coefficient of determination (R²) of 0.68. Complementary information for evapotranspiration and soil moisture across sub-basins successfully allowed consistent spatially distributed hydrological variables to be simulated. The model performance for validation using ET data was higher (NS = 0.77) compared to previous streamflow-only calibration strategies for flow (NS = 0.42) and soil moisture (NS = 0.46). Under the CC scenarios, natural vegetation restoration would compensate reductions in water availability.

The main reason for the appearance of pharmaceutical compounds in the aquatic environment is their regular excretion by humans and animals in an unchanged form or slightly metabolized. Pharmaceuticals limit the habitable living environment for aquatic organisms, because they can be toxic not only to bacteria but also to non-target organisms. Plants of the Lemnoideae subfamily and crustaceans Daphniindae family are widely used as bioindicators in freshwater environmental risk assessments. This study aimed to use biotests (Lemna test and Daphtoxkit) to determine the effect of two pharmaceuticals: antibiotic – Doxycycline (DOX) and semi-synthetic chemotherapeutic drug – Norfloxacin (NOR) on plants Lemna minor and crustaceans Daphnia magna. Standard Lemna test was extended to include pharmaceutical effects on plant chlorophyll content (LCC) and fluorescence (Fo, Fm, and Fv/Fm), and the confirmation of drug toxicity was the biotest Daphtoxkit assessing the immobilization (IM) of organisms. Studies have shown that DOX was more toxic than NOR on tested aquatic organisms: plants and crustaceans. The lowest observed effect concentration (EC₂₀) of DOX and NOR reduced by 20 % LCC and Iy of L. minor was 2.14 and 8.11 mg × L ^{− 1}, respectively. The LCC was an early and sensitive indicator of the phytotoxic effects of DOX in L. minor before morphological changes were observed. Confirmation of drug toxicity was the Daphtoxkit. The EC₂₀ (180. min) of DOX and NOR, IM of daphnia by 20 % was 117.18 and 215.42 mg × L ^{− 1}, respectively. In conclusion, DOX and NOR in aquatic environments may have significant implications for tested organisms and their ecosystems.

As stormwater management embarks on a new journey of resource allocation and disparity, addressing the contamination resulting from deicing salts is a growing concern for designers and land planners. Turf and native grass variety are currently one of the most readily available and adaptive resources to address some of these ever increasing hydrologic concerns. However, little is known about the water quality efficiency and optimal design layout of turf and native grasses in urban or rural landscapes with regards to salt remediation. In this study, a five plot series of grass swales was utilized in this study to measure water quality efficiency and salt tolerance of turf and native grasses. The grass varieties that were tested in this study include; Common hard fescue (Festuca trachyphylla), Chewings fescue (Festuca rubra commutata), and sheep fescue (Festuca ovina). Results showed that the grass swales that made up of a blend of grass variety were the most successful at reducing saline and TDS levels as compared to their monoculture counterparts. The findings reveal that a relatively simple grass swale could provide excellent salt and TDS reduction when utilizing a blend of grass varieties; specifically a hard fescue and sheep fescue blend.

A common method of preparing water samples for environmental DNA isolation is to vacuum filter the water sample through membrane filters. The aim of research was to test the performance of five methods of preparing river water samples for DNA isolation. DNA was isolated using a commercial kit and next-generation sequencing was performed on an Illumina Miseq platform. Pseudomonas spp. was the dominant bacterial genus in all samples. However, its relative abundance varied between samples. Depending on the volume of water filtered, the eluates yielded 62–63 % (V = 100 mL), 59–63.9 % (V = 50 mL), 17.8–19.4 % (V = 500 mL) of the relative abundance of Pseudomonas sp. In contrast, DNA isolation from the membrane filter (V = 100 mL) yielded 38 % and from the sediment after centrifugation 27 %. Differences were observed for all taxa obtained. The results indicate that even the sample volume used for filtration influences the results obtained from next-generation sequencing.

This study provides a unique opportunity to realistically assess the impact of tourism pressure on the water quality of lakes. A quantitative analysis of the physicochemical and microbiological parameters of water during and after the COVID-19 lockdown period was made. The study covered Sztynorckie Lake located in the Great Masurian Lakes System (GMLS) (northeastern Poland), which is a holiday destination for hundreds of thousands of holidaymakers, and serves as a pillar of the local economy. Significant improvement in the microbiological water quality was observed only during the drastic reduction of human activity due to the pandemic-enforced lockdown. This was confirmed by the results of PCA (X-axis explains 88 % of the variability of the analyzed samples; statistical significance of p<0.05). The rapid increase in the number of coliforms and Escherichia coli (613.1 MPN/100 mL) in the first weekend after the lockdown (June 2020) indicates a point discharge of sewage (including fecal pollution). Illegal discharge of sewage and wastewater is a highly reprehensible offense, and radical legal steps should be taken to prevent it and to protect the water quality. No significant relationship was found between the lockdown and the lake water's physicochemical conditions. In the spring, increased primary production was evidenced by the high concentration of chlorophyll a (52.5 to 70.5 μg/L), suspended particulate matter (20.4 to 21.0 mg/L) and total organic carbon (20.7 to 22.7 mg/L). This is a warning that a nutrient-rich lacustrine ecosystem cannot be restored quickly.

The dynamic of different grass strips width effects on runoff-sediment reduction benefit are not clearly understood. Thus, we aim to determine the optimum grass strips width on runoff-sediment reduction benefits on inceptisols slopes. In this work, using a soil flume as a carrier, we analyzed the influences of flow rate and grass strips width on runoff and sediment yield, as well as determined the optimum grass strips width on runoff and sediment reduction benefit through simulated scouring experiments under different flow rates (4, 6 and 8 L/min) and grass strips widths (0.50, 0.75 and 1.00 m). The results showed that 1) the runoff coefficient increases binomial with increasing scouring time, and the runoff and sediment yield of grass strips were much lower than those of bare soil under a given flow rate. 2) Compared to the bare slope, the mean runoff and sediment reduction benefits of the average grass strips width were 27.20% and 43.66%, respectively. 3) The 1.00 m grass strips width had a great runoff-sediment benefit for controlling the soil erosion, and the runoff-sediment reduction benefit was more sensitive to changes in grass strips width than to flow rate. Therefore, we can conclude that the 1.00 m grass strips width was the optimal grass strips width for reducing the runoff and sediment yield. These results have theoretical and practical significance for preventing water and soil loss on purple soil sloping farmland.

The differences in soil water content across the soil profiles produce changes in soil microbial and enzymatic properties, which play a major role in the transformation of soil organic matter. Permanent water saturation contributes to the formation of gleyic/stagnic horizons which have reducing conditions, this leads to a depletion in soil oxygen and changes in soil properties. To assess the effect of water content, we compared soil properties in the gleyic/stagnic horizons to the oxidative layers, which occurred at the same/similar depth in other profiles. The enzymatic activity and the number of microbial groups were assessed in eight soil profiles located in central Poland.

The studied properties responded differently to the water content. As expected, nitrate-reductase activity and the nitrate content were significantly higher in gleyic/stagnic than in oxidative conditions, while the opposite trend was found for phenol oxidase, urease, N-acetyl-glucosaminidase activity and the fungi number. No clear response in the total bacteria and facultative anaerobic bacteria (Bfa) count toward oxidation-reduction conditions was found. The dehydrogenases did not have a higher activity in the gleyic/stagnic as compared to the oxidative horizons and did not correlate significantly with the Bfa count. Differences in enzyme activities may be caused by the fact that the variation in frequency and duration of the reducing conditions in the soils may be insufficient to affect the short-term dynamics of these enzymes. The higher activity of some hydrolases in the reducing horizons may also be associated with the greater carbon and nitrogen content in these horizons.

Artificial waterways are characterized by dams and locks that slow water flow. Such conditions can influence the environment of freshwater organisms, including the zooplankton community. Our research aimed to assess the impact of environmental and hydrological conditions on the zooplankton of sites upstream and downstream of canal locks. The study was carried out in 2021 and 2022. Water samples were collected monthly from two canals during the growing season. We evaluated how water flow velocity and selected environmental parameters (i.e., water temperature, Secchi disk visibility, conductivity, oxygen concentration, saturation, pH and chl-a concentrations) influence the zooplankton diversity (T) density (N) and biomass (B). Our study showed that the zooplankton of the canals was highly diverse. Rotifers dominated over crustaceans in diversity and density at all sites of canals. The statistical analysis revealed differences in environmental and biological conditions between habitats located upstream and downstream of locks. Rotifers density and biomass changed approximately proportionally to changes in chlorophyll at sites upstream of locks. It supports the hypothesis that rotifer communities are defined by the bottom-up effect linked to food supply (phytoplankton). The growth of crustaceans (density and biomass), as well as total zooplankton biomass, was affected by water temperature at sites downstream of the lock.