Eutrophication Of Water Bodies Research Articles

Cyanotoxins bioaccumulation by fish in an anthropized reservoir in central Mexico

The bioaccumulation of cyanotoxins has been well documented in exposed organisms including fish, which represent a potential route to cyanotoxins transfer to humans by consumption of contaminated food. We determined the bioaccumulation of neurotoxic saxitoxins and hepatotoxic microcystins in muscle and liver/viscera of native (Goodea atripinnis), introduced (Poeciliopsis gracilis), and commercially important (Oreochromis niloticus) fish in Santa Catarina, an anthropized reservoir in Central Mexico. Additionally, we calculated the potential risk of human exposure due to the consumption of the studied species. The Santa Catarina Reservoir showed some physical and chemical water parameters generally associated with cyanobacterial blooms (e.g., high phycocyanin, chlorophyll-a, dissolved phosphorus concentrations, and alkaline pH) with presence of cyanotoxins produced by the cyanobacteria genera Microcystis, Dolichospermum, and Planktothrix, which were found in dissolved and particulate (sestonic) fractions of water. Moreover, we detected the presence of saxitoxins and microcystins in the tissues of all species studied. The risk of intoxication for humans was lower for the consumption of Nile tilapia muscle than for the other analyzed species, whose consumption should be avoided since it exceeds the recommended daily intake of microcystins for a short-term (i.e., two-week exposure time). These findings are remarkable because commercial fishing in reservoirs and the consumption of these fish could represent a route to human exposure to toxins, particularly microcystins. Our results highlight the need for the detection of cyanotoxins and the evaluation of their bioaccumulation by fish in unstudied eutrophic waterbodies, to reduce the potential health risk for humans and the environment.

Algal blooms exacerbate cadmium/zinc bioaccumulation in filter-feeding fish in contaminated water: Mechanisms and environmental implications

Eutrophic waters experiencing cyanobacterial blooms often contain high levels of heavy metal pollutants, including cadmium (Cd) and zinc (Zn). The transfer mechanisms of Cd and Zn within the water-algae-fish system, however, remain poorly understood. This study investigates the accumulation and transfer of Cd and Zn in a simulated water-algae‑silver carp (Hypophthalmichthys molitrix) ecosystem during Microcystis aeruginosa (M. aeruginosa) blooms. Algae demonstrated significant bioaccumulation of Cd and Zn, with Zn proving more toxic to the algae than Cd. In silver carp, the accumulation of Cd and Zn was strengthened in the intestine, liver, and skin following ingestion of M. aeruginosa enriched with these metals. This resulted in a 31% increase in Cd enrichment in the intestine, liver, and a 72% increase in the skin, compared to systems without M. aeruginosa. Zn enrichment in the liver and skin increased by 53% and 61%, respectively. However, muscle accumulation of Cd and Zn showed only minor increases of 0.59 and 3.93 mg/kg. This study elucidated that algae exacerbated the bioaccumulation of Cd and Zn in silver carp through mechanisms such as digestion, absorption, and skin mucosal contact in ecosystems experiencing M. aeruginosa blooms. The accumulation and food chain amplification of heavy metals in eutrophic water bodies increase the ecological toxicity risk to aquatic organisms and local residents. Measures should be considered to simultaneously control both eutrophication and heavy metal pollution in water bodies, with overall results contributing to the scientific management of eutrophic waters containing heavy metals.

EVALUATION OF THE CARBON FOOTPRINT IN THE TREATMENT OF URBAN WASTEWATER IN THE CANARY ISLANDS (SPAIN)

ABSTRACT: Wastewater treatment plants play an important role within the urban water cycle to prevent the natural water environment and human health from being negatively affected by human activities. However, wastewater treatment processes, such as effluent discharge and indirect emissions resulting from energy or chemical production, also negatively affect the environment. Footprints have been used to track human influence on the environment in different areas of interest and have been applied to assess the sustainability of wastewater treatment plants. In this article, a comprehensive review of footprint assessment was investigated to evaluate the wastewater treatment process in wastewater treatment plants. The review showed that carbon footprinting was used to assess the sustainability of WWTPs, and that other footprint assessment applications (such as nitrogen and phosphorus footprinting) were also introduced to assess eutrophication of water bodies. To promote the application of footprint assessment, this article regulates the study objectives, frameworks, system boundaries, data processing methods, and the resulting interpretation process. The pros and cons of the footprint assessments were discussed and investigated in detail, examining the CO2 production on each island of the Canary archipelago, and several suggestions were proposed to improve the footprint assessments. Analysis of footprint assessments at different wastewater treatment plants revealed that wastewater treatment technologies and scales had a significant impact on footprints. Furthermore, research hotspots identified using a keyword network diagram showed that the water-carbon-energy nexus was a promising direction for future studies. The purpose of the study is to improve the reduction of the carbon footprint both at the level of direct and indirect emissions factors using new tools and methodologies. Key Words: Footprint; Waste water; Canary Islands

Assessing the accuracy of an infrared-converted drone camera with Orange-Cyan-NIR filter for vegetation and environmental monitoring

Drones equipped with cameras sensitive to near-infrared wavelengths are increasingly being used in environmental assessment studies and in agriculture. These cameras are sensitive to vegetation cover, extent of eutrophication in water bodies, and aspects of crops such as growth vigour, biomass and potential yield. Single-sensor (‘RGB’) cameras with modified spectral filters that allow for capturing near-infrared wavelengths offer a low-cost alternative to multi-sensor multispectral cameras or spectrometers. However, some studies point to lower measurement accuracies by such infrared converted sensors. So, to what extent can infrared converted cameras be used to quantify vegetation condition? This case study compared vegetation indices calculated from infrared converted camera imagery to those measured by a drone-borne multispectral camera and a handheld NDVI meter, as captured over soybean and potato fields. The study found that infrared converted camera derived NDVI was consistently lower over vegetation than NDVI measured from the multispectral and handheld sensors. Further, all considered indices of the infrared converted camera displayed relative underestimation at high index values, but over estimation at low index values. The study builds on previous case studies with similar results by further evaluating the reflectance patterns of the individual image bands to find possible reasons for the discrepancy in vegetation index measurements. There is good agreement between the near-infrared bands of the respective sensors (), but the respective red bands have weak correlation (). We discuss possible reasons for the lower vegetation index measurements observed by the infrared converted camera, noting broad band sensitivities, and differing central wavelengths, which may have caused overestimated reflectance in the red band. All processing and analysis were executed with open-source software, and source code is made available to support reproducible research.

Simultaneous removal of calcium, phosphorus, and bisphenol A from industrial wastewater by Stutzerimonas sp. ZW5 via microbially induced calcium precipitation (MICP): Kinetics, mechanism, and stress response

The biological treatment of complex industrial wastewater has always been a research hotspot. In this experiment, a salt-tolerant strain Stutzerimonas sp. ZW5 with aerobic denitrification and biomineralization ability was screened, and the optimum conditions of ZW5 were explored by kinetics. The removal efficiencies of nitrate (NO3--N), bisphenol A (BPA), phosphorus (PO43--P), and calcium (Ca2+) were 94.47%, 100%, 98.87%, and 83.04%, respectively. The removal mechanism of BPA was the adsorption of microbial induced calcium precipitation (MICP) and extracellular polymeric substances (EPS). Moreover, BPA could weaken the electron transfer ability and growth metabolism of microorganisms and affect the structure of biominerals. At the same time, the stress response of microorganisms would increase the secretion of EPS to promote the process of biomineralization. Through nitrogen balance experiments, it was found that the addition of BPA would lead to a decrease in the proportion of gaseous nitrogen. This experiment offers novel perspectives on the treatment of industrial effluents and microbial stress response. Environmental ImplicationNitrate and PO43--P in industrial wastewater led to eutrophication of water bodies, and BPA has a negative effect on the endocrine of aquatic organisms. In this experiment, a salt-tolerant strain ZW5 capable of efficient aerobic denitrification and biomineralization was screened. The strain ZW5 produced alkalinity in denitrification to promote the MICP, and BPA was adsorbed by hydrogen bonding and pore interaction through MICP and EPS. It was further studied that BPA would cause strain ZW5 to secrete more EPS and improve the MCIP. This experiment offers new insights into industrial wastewater treatment and the stress response of microorganisms.

Management of eutrophication using combined the “flock & sink” mitigation technique and submerged plants restoration: a mesocosm study

Abstract Currently, the issue of eutrophication and cyanobacterial blooms persists in water bodies worldwide, prompting the exploration of various treatment methods. This study conducted a comparative analysis of eutrophic water bodies using ferric chloride-modified zeolite (FMZ) and calcium hydroxide-modified zeolite (CMZ) combined with Elodeanuttallii (E. nuttallii) for removal and purification effects. The results revealed that the addition of E. nuttallii had a sustained inhibitory effect on phosphorus release, maintaining stability with lower Turbidity(Tur) and stabilized pH within the range of 8.5-9. FMZ demonstrated rapid reduction in dissolved phosphorus concentration, achieving a removal rate of 96% within 3 days. The combined plant group of CMZ and FMZ exhibited synergistic effects with E. nuttallii, achieving an impressive total phosphorus (TP) removal rate of 80.13% and a total nitrogen (TN) removal rate of 48.77%. Additionally, chlorophyll a (Chl a) concentration decreased from 100.74 ± 24.72 μg/L to 49.96 ± 2.08 μg/L. The phytoplankton community composition indicated that diatoms thrived in low temperatures and high NH4 conditions. Under the same low Total Nitrogen to Total Phosphorus (TN:TP) ratio, high TP concentrations were associated with cyanobacteria dominance, while green algae dominated in other scenarios. This comprehensive approach demonstrates the potential efficacy of CMZ and FMZ combined with E. nuttallii in addressing eutrophic water bodies and mitigating cyanobacterial blooms.

An innovative method based on Gaussian cloud distribution and sample information richness for eutrophication assessment of Yangtze's lakes and reservoirs under uncertainty.

The precise assessment of a water body's eutrophication status is essential for making informed decisions in water environment management. However, conventional approaches frequently fail to consider the randomness, fuzziness, and inherent hidden information of water quality indicators. These would result in an unreliable assessment. An enhanced method was proposed for the eutrophication assessment under uncertainty in this study. The multi-dimension gaussian cloud distribution was introduced to capture the randomness and fuzziness. The Shannon entropy based on various sample size and trophic levels was proposed to maximize valuable information hidden in the datasets. Twenty-seven significant lakes and reservoirs located in the Yangtze River Basin were selected to demonstrate the proposed method. The sensitivity and consistency were used to evaluate the accuracy of the proposed method. Results indicate that the proposed method has the capability to effectively assess the eutrophication status of lakes and reservoirs under uncertainty and that it has a better sensitivity since it can identify more than 33-50% trophic levels compared to the traditional methods. Further scenario experiments analysis revealed that the sample information richness, i.e., sample size and the number of trophic levels is of great significance to the accuracy/robustness of the method. Moreover, a sample size of 60 can offer the most favorable balance between accuracy/robustness and the monitoring expenses. These findings are crucial to optimizing the eutrophication assessment.

Enzymatic mechanism of MlrB for catalyzing linearized microcystins by Sphingopyxis sp. USTB-05.

Microcystins (MCs) are the most widespread cyanobacterial toxins in eutrophic water body. As high toxic intermediate metabolites, linearized MCs are further catalyzed by linearized microcystinase (MlrB) of Sphingopyxis sp. USTB-05. Here MlrB structure was studied by comprizing with a model representative of the penicillin-recognizing enzyme family via homology modeling. The key active sites of MlrB were predicted by molecular docking, and further verified by site-directed mutagenesis. A comprehensive enzymatic mechanism for linearized MCs biodegradation by MlrB was proposed: S77 transferred a proton to H307 to promote a nucleophilic attack on the peptide bond (Ala-Leu in MC-LR or Ala-Arg in MC-RR) of linearized MCs to form the amide intermediate. Then water was involved to break the peptide bond and produced the tetrapeptide as product. Meanwhile, four amino acid residues (K80, Y171, N173 and D245) acted synergistically to stabilize the substrate and intermediate transition states. This study firstly revealed the enzymatic mechanism of MlrB for biodegrading linearized MCs with both computer simulation and experimental verification.

Pulp mill sludges as a solution for reducing the risk of mineral nitrogen leaching from agriculture

Nitrogen (N) from agricultural systems contributes to the eutrophication of waterbodies through leaching. Incorporating organic material with a high carbon-to-nitrogen (C/N) ratio, such as mixed pulp mill sludges (PMSs), into the soil in autumn could reduce the amount of leachable N. This study tested the potential of composted and lime-stabilised mixed PMSs (CPMS and LPMS) in reducing the concentration of mineral N in the soil, and thus the risk of N leaching from arable land in the boreal region using a two-year field experiment. To better understand the mechanisms of the PMSs for influencing mineral N concentration in soil, the impact of PMSs with different quality on the reactions of N in the soil was investigated in a laboratory incubation study. In the field experiment, nitrate-N (NO3--N) concentration was lower with PMSs compared to mineral fertilisation and the control during the first autumn and the following spring after PMS application. The undersowing of Italian ryegrass reduced the NO3--N concentration in the soil during the first autumn. In the incubation experiment, PMSs reduced the soil ammonium-N (NH4+-N) concentration at the beginning of the experiment and the soil NO3--N concentration throughout the experiment compared to a mineral fertiliser treatment and an organic fertiliser. Increased soil respiration in PMS-treated soils indicated increase in microbial activity, and thus immobilisation of soil NO3--N and NH4+-N due to PMSs addition. These results suggest that PMSs have the potential to reduce N leaching from agricultural soils. However, the immobilisation of N must be considered when planning the nutrient requirements of the following crops.

Reconstruction of the currents structure in the Kuibyshev Reservoir using satellite data and field measurements

This paper is devoted to a series of the first field subsatellite experiments conducted in the waters of the Kuibyshev Reservoir (Kama estuary) in 2023. Simultaneously with ship-based measurements of current and wind fields, as well as chlorophyll-a concentration, two high-spatial-resolution satellite scanners surveyed the study area of the reservoir. From sequential images, current fields were reconstructed using the standard maximum cross-correlation (MCC) method, which were then compared with measurements from the Acoustic Doppler Current Profiler (ADCP). In certain parts of the water area, satisfactory agreement was obtained between the reconstructed currents and direct measurement current data. And in those parts of the water area where a significant discrepancy between the ADCP and MCC data was recorded, the possible reasons for the discrepancies were analyzed. Preliminary estimates of the parameters that have a significant impact on the possibility of reconstructing currents using the MCC method in inland eutrophicated water bodies have been made, and some limitations of the MCC method as a whole have been identified. Possible ways of further development of the method are analyzed.

Research on the Analysis of and Countermeasures for the Eutrophication of Water Bodies: Waihu Reservoir as a Case Study

Water quality deterioration and eutrophication have become a global concern, while reservoir pollution caused by multiple factors has led to frequent algal blooms, posing a serious threat to rural drinking water security and urban water supply. The purpose of this paper is to analyze the current water quality of Waihu Reservoir and use the single index method, the weighted comprehensive scoring method, and the nutrient level index method (TLI) to evaluate eutrophication. On this basis, the pollution sources of the reservoir are comprehensively analyzed and discussed, and effective control strategies are proposed. The evaluation results indicate that the reservoir is of moderate eutrophication type. Therefore, reducing the input of nutrients such as nitrogen and phosphorus in water is the main goal of alleviating exogenous pollution. The combination of engineering intervention and ecological restoration strategies to remove nutrients from the aquatic environment is an effective strategy to manage endogenous pollution. From the point of view of the source of pollution, this study provides an in-depth analysis of exogenous and endogenous pollution, respectively, and the proposed treatment is instructive for the control and routine management of eutrophication in the Waihu Reservoir, as well as for the management of similar problems in different reservoirs.

Study of a New Photocatalytic Film Process Combined with a Constructed Wetland and an Analysis of Reoxygenation Pathways in a Water Body

Pollution in water environments hinders both social progress and economic development. Wastewater treatment and the sustainable use of water resources are important factors in solving this problem. In a previous study, the authors proposed a process that used photocatalytic film as a back-end treatment in a composite iron–carbon constructed wetland (WIC&PF) to restore a mildly eutrophic water body. This method has strong reoxygenation effects, and can efficiently remove pollutants; these are qualities that have not been mentioned in previous studies regarding constructed wetlands. In this study, the authors further investigated the effectiveness of this process by using a photocatalytic film as a front-end treatment for a composite iron–carbon constructed wetland (PF&WIC) to restore a mildly eutrophic water body. The results showed NH4+-N, TN, TP, COD, and chlorophyll a removal rates using PF&WIC of 79.1 ± 6.6%, 76.8 ± 6.5%, 77.0 ± 5.4%, 77.3 ± 7.2%, and 91.7 ± 5.6%, respectively. The DO concentration of the water body increased compared with that of the effluent. The bacterial species and their abundance in the lake water also changed significantly, and photosynthetic autotrophic bacteria (Cyanobium PCC-6307) became the most dominant bacteria, and this played an important role in reoxygenating the water body. In comparing these results to those of our previous study, the removal of pollutants with PF&WIC was close to that with WIC&PF, but the reoxygenation effect of PF&WIC on the water body was significantly worse than that of WIC&PF; thus, WIC&PF is the more reasonable choice for treating eutrophic water bodies.

Ca–Mg modified attapulgite for phosphate removal and its potential as phosphate-based fertilizer

The urgent concerns of controlling water body eutrophication and the alleviating phosphorus shortage have led to an urgent need for action. The removal of phosphate from polluted waters and its reuse are essential for the prevention of eutrophication and for the sustainable utilization of phosphate resources. In this study, modified attapulgite with different Ca:Mg molar ratios was synthesized to facilitate the recovery of phosphate, with subsequent use of soil fertilizer. Ca–Mg modified attapulgite with the optimal ratio (ACM-5:3) exhibited an exceptional adsorption quality, achieving a maximum adsorption capacity of 63.2 mg/g. The pseudo-second-order model and Langmuir model could well describe the adsorption kinetics and isotherms, respectively. The adsorption mechanism analyses suggested that the interaction between ACM-5:3 and phosphate depended mainly on ion exchange and electrostatic attraction. Moreover, phosphate-laden-ACM-5:3 demonstrated a significant potential as a phosphorus-releasing fertilizer. It could promote corn growth by ensuring a continuous supply of phosphorus and minimizing phosphorus runoff losses. The above results suggested that ACM-5:3 was a potential adsorbent for efficient phosphate removal and recovery.

Modeling and Forecasting the Removal of Biogenic Elements from Agricultural Lands Depending on the Soil Agrophysical Properties

Introduction. Environmental pollution prevention, including prevention of water bodies, with nutrients (nitrogen and phosphorus) when they are removed from agricultural lands with possible runoff is a topical problem that requires a timely solution. The studies have found that the removal of nutrients is a result of geochemical processes, fertilization, and other factors. In this regard, mathematical modeling of the process of removal of nutrients from agricultural lands and their possible entry into water bodies is an urgent task. Aim of the Study. The study is aimed at modeling and predicting the process of possible removal of nutrients from agricultural lands to water bodies. Materials and Methods. When conducting the study, there were used well-known modeling methods. They are the methods for calculating the removal of nutrients from agricultural objects into water bodies, based on the minimum amount of initial information for predicting the eutrophication of water bodies and agrochemical methods taking into account the structure and size of field and agricultural areas, crop yields, and removal nutrients with the harvest. Results. Based on an analysis of the literature and expert judgment, a list of the most significant indicators influencing the process of nitrogen and phosphorus removal was justified. There have been developed mathematical models to determine and predict the input of nutrients from agricultural lands to water bodies. There have been found significant indicators influencing the amount of input of nutrients, such as the amount of applied fertilizers, the volume of moisture, soil water capacity, field area, depth of cultivation, etc. There is given an example of calculating the amount of input of nutrients into water bodies with a rainfall intensity of 50 mm per hour. Discussion and Conclusion. The essence of the proposed mathematical models comes down to the synthesis of numerous indicators in the complex process of removal of nutrients and their impact on water quality. The proposed mathematical models make it possible to predict the removal of nutrients from agricultural lands and to develop and implement technical and technological solutions to prevent environmental pollution.

Enhanced removal of phosphate from aqueous solutions by oxygen vacancy-rich MgO microspheres: Performance and mechanism

The efficient removal of phosphate from water environments was extremely significant to control eutrophication of water bodies and prevent further deterioration of water quality. In this study, oxygen vacancy-rich magnesium oxide (OV–MgO) microspheres were synthesized by a simple solvothermal method coupling high-temperature calcination. The effects of adsorbent dosage, contact time, initial pH and coexisting components on phosphate adsorption performance were examined. The physicochemical properties of OV-MgO microspheres and the phosphate removal mechanisms were analyzed by various characterization techniques. The maximum adsorption capacity predicted by the Sips isotherm model was 379.7 mg P/g for OV-MgO microspheres. The phosphate adsorption in this study had a fast adsorption kinetics and a high selectivity. OV-MgO microspheres had a good acid resistance for phosphate adsorption, but their adsorption capacity decreased under alkaline conditions. The electrostatic attraction, ligand exchange, surface precipitation, inner-sphere surface complexation and oxygen vacancy capture were mainly responsible for efficient removal of phosphate from aqueous solutions. This study probably promoted the development of oxygen vacancy-rich metal (hydr)oxides with potential application prospects.

Reconstructing the Holocene Development of Lake Chaika as an Example of Wetland Formation within the Sand Spit Environment Dynamics: A Case Study from the Curonian Spit, Southeastern Baltic, Russia

The paper provides original data that shed light on the formation dynamics of Lake Chaika, which is situated in the central part of the Curonian Spit and is the only large water body in the sand spits of the southeastern Baltic. Based on the multi-proxy approach, incl. investigation of the lithological structure of the bottom sediment cores, loss-on-ignition analysis, diatom analysis, study of macrofossil remains, and radiocarbon dating, we revealed that Lake Chaika was formed already in historical time, around 200 years ago. Before this period, the lake kettle, presumably, has not submerged during the Littorina transgressions, enabling the terrestrial development of the ecosystems on the moraine protrusion. During the mid-late Holocene (6700–150 cal BP), this depression was occupied by the peat-forming fen and alder carr communities. The peat deposits are separated from the overlying layers of gyttja by the thin sand horizon. We consider it a time marker for the so-called “sand disaster”, which occurred on the territory of the Curonian Spit in the 18th century (≈1700–1800). The change in the hydrological regime of the lake launched the ecosystem shifts during the last two centuries: from the water body to a wetland and vice versa. It is stated eight formation phases of the lake’s ecosystem: the terrestrial development without wet habitats (8900–6700 cal BP), the period of alder carrs (6700–3400 calBP), the sedge fen period (3400–450 cal BP), the period of inundated forest (1500–1700 AD), the “sand disaster” period (1700–1800 AD), the period of eutrophic water body (1800–1900 AD), the period of terrestrialised wetland (1900–1950 AD), and the period of secondary development of eutrophic water body (after 1950 AD).

Nature's Clean-Up Crew: Unlocking the Potential of Water Hyacinth as a Phytoremediation Wonder for Eutrophication Reduction in Aquatic Environments

This study aims to determine whether water hyacinth can be a phytoremediation tool to mitigate eutrophication in water bodies. Specifically, it seeks to observe the morphological changes in the leaves and stems of water hyacinth in terms of length and width, to describe the similarities and differences of water hyacinth from eutrophic and normal water aquariums, and to determine the efficacy of water hyacinth in mitigating eutrophication. The research employed an experimental research design, which constitutes a structured set of protocols and procedures tailored for conducting experimental investigations scientifically, employing two distinct sets of variables. In conclusion, the study found significant changes in water hyacinth's morphology when exposed to eutrophic water, with signs of distress observed after ten days due to high nutrient levels. Despite this, the findings support the potential of water hyacinth to mitigate eutrophication in water bodies, offering promise for enhanced water quality management.

Computationally characterizing the diffusive boundary layer in lakes and reservoirs

Abstract Purpose Hypolimnetic hypoxia has become increasingly prevalent in stratified water bodies in recent decades due to climate change. One primary sink of dissolved oxygen (DO) is sediment oxygen uptake ($${J}_{{O}_{2}}$$ J O 2 ). On the water side of the sediment–water interface (SWI), $${J}_{{O}_{2}}$$ J O 2 is controlled by a diffusive boundary layer (DBL), a millimeter-scale layer where molecular diffusion is the primary transport mechanism. In previous studies, the DBL was determined by visual inspection, which is subjective and time-consuming. Material and methods In this study, a computational procedure is proposed to determine the SWI and DBL objectively and automatically. The procedure was evaluated for more than 300 DO profiles in the sediment of three eutrophic water bodies spanning gradients of depth and surface area. Synthetic DO profiles were modeled based on sediment characteristics estimated by laboratory experiments. The procedure was further verified adopting the synthetic profiles. Results and discussion The procedure, which was evaluated for both measured and synthetic DO profiles, determined the SWI and DBL well for both steady and non-steady state DO profiles. A negative relationship between DBL thickness and aeration rates was observed, which agrees with existing literatures. Conclusions The procedure is recommended for future studies involving characterizing DBL to improve efficiency and consistency.

Nature's Clean-Up Crew: Unlocking the Potential of Water Hyacinth as a Phytoremediation Wonder for Eutrophication Reduction in Aquatic Environments

This study aims to determine whether water hyacinth can be a phytoremediation tool to mitigate eutrophication in water bodies. Specifically, it seeks to observe the morphological changes in the leaves and stems of water hyacinth in terms of length and width, to describe the similarities and differences of water hyacinth from eutrophic and normal water aquariums, and to determine the efficacy of water hyacinth in mitigating eutrophication. The research employed an experimental research design, which constitutes a structured set of protocols and procedures tailored for conducting experimental investigations scientifically, employing two distinct sets of variables. In conclusion, the study found significant changes in water hyacinth's morphology when exposed to eutrophic water, with signs of distress observed after ten days due to high nutrient levels. Despite this, the findings support the potential of water hyacinth to mitigate eutrophication in water bodies, offering promise for enhanced water quality management.

Macroinvertebrate and environmental responses to dredging and submerged macrophytes transplantation

Abstract Eutrophication of freshwater ecosystems is a global problem, but restoration can be difficult due to ongoing problems relating to water pollution, sedimentary nutrient stores and altered aquatic biodiversity. Mitigation of Eutrophication is often conducted alongside transplantation of submerged macrophytes and dredging, but knowledge of ecosystem response to post‐dredging transplantation of submerged macrophytes is limited. We report a long‐term (2008–2018) in situ monitoring study to evaluate the effects of different restoration measures: dredging only (Dredged) and dredged with post‐transplantation of submerged macrophytes (Dredged with macrophytes) conducted in five subtropical eutrophic lakes, Taihu basin. Water and sediment nutrients, bloom‐forming algae Microcystis and macroinvertebrate were monitored every 2 years for each treatment and compared with reference areas (Control) established in unrestored parts of the same lake. Dredging only decreased sediment nutrients (e.g. carbon, phosphorus) significantly; however, this effect diminished about 5 years later. Dredged with macrophytes had a stronger, longer lasting positive effect on water quality than dredged alone. Disturbance caused by dredging (without macrophytes transplantation) decreased the biomass of Microcystis, while transplantation of macrophytes shortly after dredging did not contribute to the decreasing of Microcystis biomass. The biomass of Microcystis in Dredged with macrophytes areas was always similar to Control over the period of our monitoring. A positive effect of submerged macrophytes transplantation post‐dredging was found for macroinvertebrate abundance and diversity: Dredged with macrophytes areas had significantly higher macroinvertebrate biomass and richness than Dredged areas after 9 years' recovery. Macroinvertebrate richness in Dredged with macrophytes areas nearly doubled compared to Control, while Dredged areas were just restored to Control levels. Synthesis and applications: Our study provides an long‐term field monitoring with new findings about the benefits and caution of submerged macrophytes transplantation post‐dredging and the effect of partial restoration, which could inform eutrophic waterbody restoration schemes.