Search Results (49)

Intensified human activities in recent years, such as wastewater discharge and agricultural non-point source pollution have led to a decline in lake water quality, especially in the middle and lower reaches of the Yangtze River Basin, which threaten the stability of lake water ecosystems. Therefore, it is necessary to conduct a scientific assessment of the water eco-environmental quality of shallow lakes and implement targeted management measures. Considering the characteristics of shallow lakes, major ecological and environmental issues, and current standards and guidelines, an indicator system method was employed to establish a water eco-environmental quality evaluation system tailored for typical shallow lakes in the middle and lower reaches of the Yangtze River Basin. This evaluation system comprises three criteria layers (aquatic organism, habitat quality, and water quality) and 10 indicator layers. Using survey data from 2022 to 2024 for evaluation, the results showed that the water eco-environmental quality of Lake Gehu was rated as poor, with the lowest score for macrophyte coverage and the highest score for riparian vegetation coverage. This indicates that the shoreline restoration project in Lake Gehu was effective, while the lake water quality still needs improvement. Remedial measures include increasing aquatic vegetation coverage, reducing nitrogen and phosphorus pollution loads, and controlling the occurrence of algal blooms. This evaluation system combines field surveys with remote sensing monitoring data, fully considering historical and current conditions, and can guide local authorities in evaluating lake water environmental quality. The constructed evaluation system is applicable for the assessment of shallow lakes in the middle and lower reaches of Yangtze River Basin. It provides a scientific basis for the continuous improvement of eco-environmental quality and the construction of Beautiful Lakes Initiative, contributing to the management and protection of lake ecosystems. Full article

The Arabian Gulf, bordered by major energy-producing nations, harbors diverse microalgal communities with strong potential for the bioremediation of environmental pollutants, particularly petroleum hydrocarbons. This review evaluates two key microalgal groups—micro-green algae and dinoflagellates—highlighting their distinct physiological traits and ecological roles in pollution mitigation. Dinoflagellates, including Prorocentrum and Protoperidinium, have demonstrated hydrocarbon-degrading abilities but are frequently linked to harmful algal blooms (HABs), marine toxins, and bioluminescence, posing ecological and health risks. The toxins produced by these algae can be hemolytic or neurotoxic and include compounds such as azaspiracids, brevetoxins, ciguatoxins, okadaic acid, saxitoxins, and yessotoxins. In contrast, micro-green algae such as Oedogonium and Pandorina are generally non-toxic, seldom associated with HABs, and typically found in clean freshwater and brackish environments. Some species, like Chlorogonium, indicate pollution tolerance, while Dunaliella has shown promise in remediating contaminated seawater. Both groups exhibit unique enzymatic pathways and metabolic mechanisms for degrading hydrocarbons and remediating heavy metals. Due to their respective phycoremediation capacities and environmental adaptability, these algae offer sustainable, nature-based solutions for pollution control in coastal, estuarine, and inland freshwater systems, particularly in mainland Qatar. This review compares their remediation efficacy, ecological impacts, and practical limitations to support the selection of effective algal candidates for eco-friendly strategies targeting petroleum-contaminated marine environments. Full article

The western region of Lake Erie has been experiencing severe water-quality issues, mainly through the infestation of algal blooms, highlighting the urgent need for action. Understanding the drivers and the intricacies associated with algal bloom phenomena is important to develop effective water-quality remediation strategies. In this study, the influences of multiple bloom drivers were explored, together with Harmonized Landsat Sentinel-2 (HLS) images, using the datasets collected in Western Lake Erie from 2013 to 2022. Bloom drivers included a group of physicochemical and meteorological variables, and Chlorophyll-a (Chl-a) served as a proxy for algal blooms. Various combinations of these datasets were used as predictor variables for three machine learning models, including Support Vector Regression (SVR), Extreme Gradient Boosting (XGB), and Random Forest (RF). Each model is complemented with the SHapley Additive exPlanations (SHAP) model to understand the role of predictor variables in Chl-a estimation. A combination of physicochemical variables and optical spectral bands yielded the highest model performance (R² up to 0.76, RMSE as low as 8.04 µg/L). The models using only meteorological data and spectral bands performed poorly (R² < 0.40), indicating the limited standalone predictive power of meteorological variables. While satellite-only models achieved moderate performance (R² up to 0.48), they could still be useful for preliminary monitoring where field data are unavailable. Furthermore, all 20 variables did not substantially improve model performance over models with only spectral and physicochemical inputs. While SVR achieved the highest R² in individual runs, XGB provided the most stable and consistently strong performance across input configurations, which could be an important consideration for operational use. These findings are highly relevant for harmful algal bloom (HAB) monitoring, where Chl-a serves as a critical proxy. By clarifying the contribution of diverse variables to Chl-a prediction and identifying robust modeling approaches, this study provides actionable insights to support data-driven management decisions aimed at mitigating HAB impacts in freshwater systems. Full article

Numerous remediation strategies exist for cyanobacterial harmful algal blooms (cyanoHABs); however, most are limited by challenges of scalability and adverse off-target effects on the surrounding ecosystem. Germicidal ultraviolet light (UV-C) has emerged as a promising method for suppressing cyanoHABs in a sustainable, chemical-free manner that is both scalable and results in limited off-target ecological effects in the surrounding area. In this study, the US Army Engineer Research and Development Center’s (ERDC)’s CyanoSTUN^TM (Cyanobacterial Suppression Through Ultraviolet-Light-C Neutralization) vessel was deployed to a cyanoHAB as part of a field trial to determine whether UV-C could effectively suppress cellular growth, degrade associated cyanotoxins, and inhibit harmful phytoplankton species more readily than beneficial species without the addition of chemicals. The cyanoHAB exhibited an average cyanobacteria abundance of 3.75 × 10⁵ cells/mL (n = 5, SD = 6.76 × 10⁴ cells/mL) and average total microcystin concentration of 3.5 µg/L (n = 5; SD = 0.24 µg/L). Pre- and post-treatment samples were collected and re-grown for 9 days in the laboratory to observe differences in microcystin, chlorophyll a, and phycocyanin concentrations, optical density, cell density, and community composition. The results of the field trial showed that the CyanoSTUN UV-C treatment effectively suppressed the growth of the cyanobacteria community for approximately two days at the three tested UV-C doses. The CyanoSTUN UV-C treatment also demonstrated a sustained, dose-dependent effect on microcystin concentration; the average reduction in microcystin concentration for 15, 30, and 45 mJ/cm² treatment doses was 31.6% (n = 10, SD = 20.1%; 1.3 µg/L reduced), 45.7% (n = 10, SD = 10.8%; 1.9 µg/L reduced), and 49.9% (n = 10, SD = 8.2%; 1.7 µg/L reduced), respectively, over the 9-day regrowth period. Non-cyanobacteria were too scarce in this CyanoHAB to conclude whether the CyanoSTUN UV-C inhibits harmful phytoplankton species more readily than beneficial species. Further field studies with the CyanoSTUN^TM are required to validate performance under more severe cyanoHAB conditions, however the results reported herein from the first field trial with the CyanoSTUN^TM suggest that this treatment method may offer water managers confronted with a CyanoHAB the ability to rapidly and safely pause a bloom for multiple days and reduce the risks posed by its associated cyanotoxins without adding chemicals. Full article

Phosphate pollution in aquatic environments leads to eutrophication and harmful algal blooms, significantly impacting ecosystems and water quality. The current study evaluates the effectiveness of surface-modified activated carbon (SMAC) in suppressing phosphate release from sediments. Using soil samples from Daecheong Lake, the performance of SMAC adsorption for phosphate was analyzed under various SMAC modification scenarios. Experiments showed that SMAC achieved approximately twice the phosphate removal efficiency compared to conventional activated carbon, with increasing effectiveness under higher flow velocities. Additionally, SMAC significantly reduced phosphate concentrations within the sediment layers, proving its effectiveness in the soil remediation process as well. The results highlight SMAC as a promising solution for mitigating pollutant release in rivers, lakes, and coastal areas, offering both short-term and cumulative long-term benefits for water quality improvement and ecosystem protection. Full article

High phosphorus (P) content and eutrophication are chemically and biologically related processes. Reducing phosphorus levels in water is essential for controlling eutrophication. In this study, biochar was produced from cyanobacteria biomass and evaluated as an adsorbent for phosphorus removal from water. The cyanobacterial biomass was collected from a local swamp in the “Departamento del Atlántico”, Colombia, and heated at 350 °C for 2 h to induce partial carbonization. The resulting biochar was characterized using vibrational spectroscopy and scanning electron microscopy (SEM/EDS). The adsorption capacity of cyanobacteria-derived biochar was assessed through kinetic and isothermal adsorption studies. The kinetic analysis revealed a maximum adsorption capacity of 5.51 mg/g and a rate constant of 0.084 g mg⁻¹ min⁻¹, with the pseudo-second-order model providing the best fit. The isotherm analysis showed that the Langmuir model accurately described the adsorption process, with an adsorption constant (K_L) of 0.360 L mg⁻¹, suggesting monolayer adsorption on the biochar surface. These results confirm that biochar obtained from cyanobacterial blooms is an effective and sustainable material for phosphorus removal from aqueous solutions, offering a promising strategy for nutrient pollution control and environmental remediation. Full article

To address freshwater lake blooms resulting from eutrophication, the application of quaternary ammonium compounds as algaecides serves as an effective emergency remediation strategy. Didecyl methylpropyl ammonium iodide (DMPAI) is a novel quaternary ammonium algaecide; however, its bacteriostatic properties may significantly disrupt the microbial activity in lakes, particularly within the lake–terrestrial ecotone. To investigate the degradation process of DMPAI in the lake–terrestrial ecotone and its impact on the microbial community, experiments were conducted using a large-scale indoor simulation device to analyze DMPAI concentrations, the composition of the lake microbial community, and associated gene functions. The results showed that (1) DMPAI was completely removed from the lake water body in approximately 36 h; (2) The addition of DMPAI altered the microbial community structure in the lake–terrestrial ecotone, as evidenced by an increase in the diversity index and the proliferation of microorganisms capable of tolerating and degrading DMPAI, such as Pseudomonas and Flavobacterium, within a short period. These changes were typically observed after 10 d and generally recovered, not persisting for extended periods. (3) Functional genes involved in carbon, nitrogen, and sulfur cycling are more significantly impaired in the lake–terrestrial ecotone with DMPAI addition. The destabilization of the microbial community may lead to a short-term increase in pathogenic bacteria during the recovery process. This phenomenon was more pronounced in environments with higher concentrations of DMPAI. Therefore, the concentration of DMPAI should be controlled within the range of 0.5 to 2.0 mg L⁻¹. Full article

Reported incidences of cyanobacterial harmful algal blooms (CHABs) are increasing across the world due to climate change and nutrient loading, dominating freshwater ecosystems and producing dangerous cyanotoxins that cause ecological damage. Microcystis aeruginosa is one of the most common species of cyanobacteria; it produces hepatotoxic and neurotoxic microcystin-LR. The ecological and human impact of algal blooms is immense, and traditional CHAB remediation methods are not always adequate in eutrophic regions such as Lake Erie in North America. As a result, a proactive, targeted approach is needed to bioremediate cyanobacteria in their pre-colonial stages. Nematodes, such as the model organism Caenorhabditis elegans, are potential candidates for bioremediating cyanobacteria such as M. aeruginosa. C. elegans have metabolic pathways that could detoxify microcystin-LR and enable tolerance to cyanobacteria in nature. We analyzed C. elegans health and fat accumulation on a diet of toxic M. aeruginosa and found that C. elegans can ingest, digest, metabolize, and survive off of this diet. The mean lifespans of the worm populations were only slightly different at 20.68 ± 0.35 (mean ± S.E.M) and 17.89 ± 0.40 when fed E. coli and toxic M. aeruginosa, respectively. In addition, a diet of toxic M. aeruginosa compared to E. coli did not have any significant impact on C. elegans pharyngeal pumping (304.2 ± 9.3 versus 330.0 ± 10.4 pumps/min), dauer response (86.3 ± 1.0 versus 83.65 ± 1.0% in dauer), mobility (209.25 ± 7.0 versus 210.15 ± 4.4 thrashes/min), or SKN-1 expression based on SKN1::GFP fluorescence measurements. Overall, a diet of toxic M. aeruginosa was able to sustain C. elegans development, and C. elegans was tolerant of it. These results suggest that C. elegans and similar nematodes could be viable candidates for cyanobacterial bioremediation. Full article

Qionghai Lake is an important freshwater source in the Yunnan–Guizhou Plateau. However, cyanobacterial blooms have been observed recently in Qionghai Lake, but their formation mechanism and control management are not well understood. Herein, phytoplankton, zooplankton, eutrophication, nutrients, and biochemical indices were measured in Qionghai Lake from May 2022 to April 2023. The results showed that cyanobacterial blooms in Qionghai Lake predominated in Anabaena sp. with a density of 1.11 × 10⁷–18.87 × 10⁷ cells/L. Anabaena blooms started in the northwestern area of Qionghai Lake in November 2022 and then expanded to the entire lake until it peaked and subsided in February 2023. Protozoa dominated in zooplankton while having no significant relationship with Anabaena blooms in Qionghai Lake. The trophic level index and chlorophyll a showed similar spatiotemporal trends with Anabaena sp. density, and water quality in the northwest of the Qionghai Lake was worse than in other parts. Total nitrogen (TN) and total phosphorus (TP) were 0.41–0.54 and 0.021–0.045 mg/L from November 2022 to February 2023. TN and TP were positively correlated with Anabaena sp. density, but TP was the most significant environmental factor affecting Anabaena bloom in Qionghai Lake. These findings might provide essential information for improving bloom control and water quality remediation in Qionghai Lake. Full article

Transgenerational plasticity (TGP) refers to the influence of ancestral environmental signals on offspring’s traits across generations. While evidence of TGP in plants is growing, its role in plant adaptation over successive generations remains unclear, particularly in floating plants facing fluctuating environments. Duckweed (Lemna minor), a common ecological remediation material, often coexists with the harmful bloom-forming cyanobacterium Microcystis aeruginosa, which releases a highly toxic exudate mixture (MaE) during its growth. In this study, we investigate the TGP of duckweed and its adaptive role under stress from MaE during the bloom-forming process. We found that exposure to MaE induces significant phenotypic plasticity in duckweed, manifested by alterations in morphological, physiological, and transcriptomic profiles. Specifically, MaE exposure significantly affected duckweed, promoting growth at low concentrations but inhibiting it at high concentrations, affecting traits like biomass, frond number, total frond area, and photosynthetic efficiency. Additionally, the activities of antioxidant enzymes, together with the levels of proline, soluble sugars, and proteins, are elevated with increasing MaE concentrations. These plastic changes are largely retained through asexual reproductive cycles, persisting for several generations even under MaE-free conditions. We identified 619 genes that maintain a ‘transcriptional memory’, some of which correlate with the TGP-linked alterations in morphological and physiological traits in response to MaE stress. Notably, progeny from MaE-exposed lineages demonstrate enhanced fitness when re-exposed to MaE. These results enhance our comprehension of the adaptive significance of TGP in plants and suggest feasible approaches for utilizing duckweed’s TGP in the bioremediation of detrimental algal blooms. Full article

Propolis is a sustainable and environmentally friendly agrochemical of natural origin, a resinous mixture produced by honeybees. It is used as a natural remedy in multiple pathologies., but it is also a natural defense enhancer, a phytostimulator that helps to bind, bloom, and pollinate plants. Propolis is used in organic farming as a phytoprotector and phytostimulator. The present study investigates the main physical–chemical parameters of Romanian propolis, its antifungal activity against five fungal strains (Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Fusarium oxysporum, and Rhizopus stolonifer) and its phyto-inhibitory activity when it is applied on the layer and under the layer for different grain crops (wheat, maize, oats, and barley). Different doses were used—1, 5, and 10 g of propolis powder—and the growth of the plume was monitored for 13 days. The physical–chemical parameters investigated are volatile oils, wax, oxidation index, melting point, dry matter, ash, and resin, and maximum values were obtained for phenols (189.4 mgGAE/g), flavonoids (84.31 mgQE/g), and IC₅₀ (0.086 µg/mL). Propolis demonstrates high antifungal activity against all fungal strains. The results showed that propolis has the best phyto-inhibition potential among the studied grain crops when it is applied on the layer, with the lowest plume growth for maize (14 mm), followed by oats, barley, and lastly wheat (24 mm). Propolis can find increasing application in sustainable and environmentally friendly agriculture and the obtaining of organic food. Full article

The purpose of this research is to examine the benefits and limitations of the implementation of novel digital academic advising systems based on the principles of authentic outcome-based education (OBE) using automated collection and reporting processes for Accreditation Board for Engineering and Technology (ABET) student outcomes data for effective developmental advising. We examine digital developmental advising models of undergraduate engineering programs in two universities that employ customized features of the web-based software EvalTools^® 6.0, including an advising module based on assessment methodology incorporating the faculty course assessment report, performance indicators, and hybrid rubrics classified according to the affective, cognitive, and psychomotor domains of Bloom’s learning model. A case study approach over a six-year period is adopted for this research. The two case studies present results of samples of developmental advising activity employing sequential explanatory mixed methods models using a combination of quantitative and qualitative analyses of (a) detailed students’ outcomes and performance indicator information and (b) self-evaluation of their professional development and lifelong learning skills. The findings of this study show that digital advising systems employing the faculty course assessment report using performance indicators and hybrid rubrics can provide comprehensive and realistic outcome data to help both developmental advisors and students easily identify the specific cause of performance failures, implement practical recommendations for remedial actions, and track improvements. Inherent strong skills can also be identified in academically weak students by observing patterns or trends of relatively better-performing outcomes to reinforce their natural affinity for learning specialized competencies to help them pursue related and successful career paths. Full article

Sunflower has substantial potential for the remediation of heavy metals in soil, but its efficiency in Cd-contaminated soil is limited, with high concentrations of Cd causing stress in plants. Exogenous Si enhances plant tolerance to heavy metals, but the mechanism for enhancing the tolerance of oil sunflower under Cd stress is not known. In potting experiments, sunflowers were grown in soil with a Cd concentration of 11.8 mg/kg soil (the maximum value in the Zhundong coal mining area of Xinjiang) and five Si treatment levels (0, 50, 250, 500, and 1500 mg/kg soil). Exogenous Si improved sunflower development, gas exchange characteristics, and antioxidant enzyme activities in sunflower compared with the Cd-only control; exogenous Si application increased Cd concentrations in sunflower roots, stems, and leaves, and Cd was mainly concentrated in sunflower roots. Sunflower biomass increased by 13.83–114.18%, and gas exchange parameters increased by 16.95–36.03%, 30.06–66.82%, and 9.77–14.71%, respectively, as compared to the control. With the increase in sodium silicate concentrations, sunflower antioxidant enzyme activities increased by 8.81–150.28%, 91.35–351.55%, and 35.11–54.69%, respectively, and MDA content decreased by 3.34–25.14% as compared to Si0. Moreover, exogenous Si increased Cd uptake and minimized Cd stress in sunflowers at the seedling and blooming stages, and it potentially facilitated the phytoremediation of Cd-contaminated soils through enriched plants such as sunflower, as well as contributing to the achievement of sustainable development of the soil environment. Full article

Aquatic ecosystems are often subject to degradation due to various environmental stressors. The accumulation of an organic sediment layer causes shallowing, algal blooms, and hypertrophy in water reservoirs. The processes of overgrowth and shallowing lead to a reduction in the ecosystem services provided by the reservoir as well as potentially causing the disappearance of the water body. To address these challenges and restore the ecological balance of water reservoirs, effective and sustainable revitalisation methods are essential. In recent years, biotechnological approaches, particularly utilizing microbiological interventions, have emerged as promising strategies for water reservoir revitalization. Microorganisms, with their remarkable ability to degrade pollutants and enhance nutrient cycling, offer great potential in remediating environmental issues in a natural and eco-friendly manner. This article presents the results of a study of 33 Polish reservoirs subjected to reclamation with microbial biopreparations from 2014 to 2023. The results of changes in bottom sediment reduction, water transparency, dissolved oxygen concentration, and water turbidity are presented. Reduction in morphological changes in the fraction of soft organic sediments, an improvement in the oxygen profile of the bottom and surface water layers, and an increase in water transparency were observed after reclamation with the use of biopreparations. Full article

The restoration of eutrophic river and lake ecosystems is an important task that has been conducted in numerous ways and at many locations around the world. However, such improvements of water quality are often temporary, as such ecosystems are dynamic, and restoration measures must be reassessed and modified. The restored catchment of a shallow eutrophic lake, Lake Seeburg, in central Germany, was monitored over a 13-month period. The restoration of the inflowing river a decade earlier included riverbed prolongation, gradient reduction, and the construction of wetlands upstream, which reduced the sediment input and silting up of the lake. As nutrient fluxes in the tributaries were still high, these restoration measures seemed to be insufficiently effective. This study aimed to locate nutrient hotspots and quantify the nutrient balances of the catchment. Nitrogen and phosphorous concentrations, river discharge, hydrochemical parameters (pH, temperature, oxygen concentrations) and turbidity, as a proxy for suspended particulate matter (SPM), were monitored monthly. Our data show that the lake functions as a nitrogen sink, whereas the phosphorous fluxes follow a seasonal trend with the negative balance in winter turning into a positive balance in summer with the onset of cyanobacterial blooms. The release of phosphorous from the wetland throughout the year indicates supersaturation and thus a permanent input of phosphorous into the lake. Consequently, phosphorus loading in the lake is quite high, fostering eutrophication. Furthermore, the very low precipitation rates during the study highlighted that the lake was not only controlled by external nutrient loads but rather was sustained by high internal phosphorous loading. Consequently, the remediation action of creating the wetland to restore the sedimentation trap and nutrient accumulation capacity was not sufficient. Full article