Invasive Aquatic Plant Research Articles

Response of four Vallisneria taxa to aquatic herbicides

Abstract Native aquatic macrophytes such as Vallisneria americana Michx. are often desirable in aquatic ecosystems due to the ecological benefits they provide but are threatened by competition from invasive taxa including nonnative Vallisneria taxa and hydrilla (Hydrilla verticillata L.f. Royle). Identifying potential selective herbicide management options can provide options to minimize impacts to native taxa in restoration and aquatic invasive plant management programs. Greenhouse mesocosm experiments were conducted in 2023 to investigate herbicide efficacy on two native eelgrass species (V. americana and V. neotropicalis Vict.), two nonnative taxa (V. australis S.W.L. Jacobs & Les and V. spiralis × V. denseserrulata Makino) and H. verticillata. Herbicide applications included endothall, diquat, florpyrauxifen-benzyl, fluridone, and flumioxazin and select combinations of these herbicides used in H. verticillata management. Endothall alone provided 90 to 100% aboveground biomass reduction at 3000 µg L-1 with at least 24 hours of continuous or intermittent exposure to all native and invasive species at six weeks after exposure, whereas florpyrauxifen-benzyl applied alone resulted in minimal aboveground biomass reduction. A 45 day of exposure of fluridone (10 µg L-1) resulted in 95% biomass reduction on V. americana and 7 to 48% other tested taxa. The combination of flumioxazin and florpyrauxifen-benzyl resulted in 90 to 100% aboveground biomass reduction and endothall combined with florpyrauxifen-benzyl resulted in 93 to 100% aboveground biomass reduction across taxa. Reductions in belowground biomass mirrored trends observed in aboveground biomass. No treatments selectively controlled invasive Vallisneria without injury to native Vallisneria, although efficacy was observed on hydrilla. These insights provide an understanding for differences between these Vallisneria for researchers moving forward with selectively targeting H. verticillata in the presence of native Vallisneria species and two new aquatic invasive plants. Future research should expand treatment scenarios, increase the study period, and identify potential integrated plant management strategies for field scenarios.

Introduction of three cryptic lineages of invasive Nymphoides cristata in the southeastern United States

Abstract Crested floating heart [Nymphoides cristata (Roxb.) Kuntze] is an invasive aquatic plant in the southeastern United States. For clonal plants like N. cristata, clonal diversity may influence response to control tactics and/or evolutionary potential. However, little is known about the diversity of introduced N. cristata. In this study, we used genotyping-by-sequencing to quantify N. cristata diversity in the southeastern U.S. and determine how that diversity is distributed across the invaded range. Our results show that at least three distinct genetic lineages of N. cristata are present in the southeastern U.S. Geographic distribution of the lineages varied, with one widespread lineage identified across several states and others only found in a single waterbody. There is also evidence of extensive asexual reproduction, with invaded waterbodies often host to a single genetic lineage. The genetic diversity reported in this study likely results from multiple introductions of N. cristata to the southeastern U.S. and should be considered by managers when assessing control tactics such as screening for biocontrol agents or herbicide testing. The extent and distribution of genetic diversity should also be considered by researchers studying the potential for invasive spread of N. cristata within the U.S. or hybridization with native Nymphoides species.

Differential photosynthetic yield across a wide range of temperatures for Northern and invasive Watermilfoils

Eurasian watermilfoil (Myriophyllum spicatum) is one of the most challenging invasive aquatic plant species in Minnesota. Eurasian watermilfoil has hybridized with the native Northern watermilfoil (Myriophyllum sibiricum), creating a more complex issue when it comes to invasions. The hybridization of watermilfoil has increased difficulty for management and an underlying biological mechanism explaining this difficulty has yet to be determined. We compared the photosynthetic temperature response of the parental Northern and Eurasian parental genotypes to five hybrid watermilfoils using pulse amplitude modulated (PAM) chlorophyll fluorometry to determine if there are intrinsic physiological differences in photosynthesis between genotypes. We examined both the ratio of variable to maximal fluorescence (Fv/Fm) and light-adapted quantum yield of photosystem II (PSII) electron transfer (ΦPSII) every 5 °C from 0 to 45 °C representing sub- to supraoptimal water temperatures. On average, hybrids had 6% and 8% higher Fv/Fm and ΦPSII values respectively, than parental genotypes across all temperatures. In both parental and hybrid genotypes Fv/Fm values were consistent from 0 to 35 °C and declined 36% as water temperature approached 45 °C. Optimal water temperature for ΦPSII was between 25-35 °C and hybrids had 17% higher values for suboptimal temperatures between 5-15 °C. Our findings indicate that although the many strains of watermilfoil are morphologically similar, they differ in their photosynthetic capacity and may indicate heterosis. Innate differences between parental strains and hybrids could impact overall primary productivity, life history characteristics, and overall invasiveness. These factors could also be contributing to the documented management failures seen in field populations.

Insights into the community structure and environmental functions of water hyacinth rhizobiome in urban river ecosystem.

Water hyacinth (WH) is a widespread floating invasive aquatic plant with a prolific reproductive and dispersion rate. With the aid of its root-associated microbes, WH significantly modulates the ecosystem's functioning. Despite their irrevocable importance, the WH microbiome remains unexplored in detail. Here, we present a shotgun sequencing analysis of WH rhizobiome predominant in urban rivers and their surrounding water to unveil the diversity drivers and functional relationship. The core microbiome of the WH mainly consisted of the methane-metabolizing archaebacteria and sulfate-reducing bacteria, which are probably driving the methane and sulfur metabolic flux along the vegetative zone in the water. The beta diversity analysis revealed temporal variations (River WH_2020 vs. WH_2022) (R of 0.8 to 1 and R2 of 0.17 to 0.41), which probably could be attributed to the transient taxa as there was a higher sharing of core bacteria (48%). Also, the WH microbiome significantly differed (R = 0.46 to 1.0 and R2 of 0.18 to 0.52) from its surrounding water. Further, the functional analysis predicted 140 pollutant-degrading enzymes (PDEs) well-implicated in various xenobiotic pollutant degradation, including hydrocarbons, plastics, and aromatic dyes. These PDEs were mapped to bacterial genera such as Hydrogenophaga, Ideonella, Rubrivivax, Dechloromonas, and Thauera, which are well-reported for facilitating the metabolism of xenobiotic compounds. The higher prevalence of metal and biocide resistance genes further highlighted the persistence of resistant microbes assisting WH in bioremediation applications.

Active remote sensing data and dispersal processes improve predictions for an invasive aquatic plant during a climatic extreme in Great Lakes coastal wetlands

Invasive aquatic plants pose a significant threat to coastal wetlands. Predicting suitable habitat for invasive aquatic plants in uninvaded yet vulnerable wetlands remains a critical task to prevent further harm to these ecosystems. The integration of remote sensing and geospatial data into species distribution models (SDMs) can help predict where new invasions are likely to occur by generating spatial outputs of habitat suitability. The objective of this study was to assess the efficacy of utilizing active remote sensing datasets (synthetic aperture radar (SAR) and light detection and ranging (LiDAR) with multispectral imagery and other geospatial data in predicting the potential distribution of an invasive aquatic plant based on its biophysical habitat requirements and dispersal dynamics. We also considered a climatic extreme (lake water levels) during the study period to investigate how these predictions may change between years. We compiled a time series of 1628 field records on the occurrence of Hydrocharis morsus-ranae (European frogbit; EFB) with nine remote sensing and geospatial layers as predictors to train and assess the predictive capacity of random forest models to generate habitat suitability in Great Lakes coastal wetlands in northern Michigan, USA. We found that SAR and LiDAR data were useful as proxies for key biophysical characteristics of EFB habitat (emergent vegetation and water depth), and that a vegetation index calculated from spectral imagery was one of the most important predictors of EFB occurrence. Our SDM using all predictors yielded the highest mean overall accuracy of 88.3% and a true skill statistic of 75.7%. Two of the most important predictors of EFB occurrence were dispersal-related: 1) distance to the nearest known EFB population (m), and 2) distance to nearest public boat launch (m). The area of highly suitable habitat (pixels assigned ≥0.8 probability) was 74% larger during a climatically extreme high water-level year compared to an average year. Our findings demonstrate that active remote sensing can be integrated into SDM workflows as proxies for important drivers of invasive species expansion that are difficult to measure in other ways. Moreover, the importance of a proxy variable for endogenous dispersal (distance to nearest known population) in these SDMs indicates that EFB is currently spreading, and thereby less influenced by within-site dynamics such as interspecific competition. Lastly, we found that extreme climatic conditions can dramatically change this species’ niche, and therefore we recommend that future studies include dynamic climate conditions in SDMs to more accurately forecast the spread during early invasion stages.

Autonomous suction harvesting as a novel approach to aquatic invasive plant control

Autonomous suction harvesting as a novel approach to aquatic invasive plant control

Modeling the Effects of Temperature and Limiting Nutrients on the Competition of an Invasive Floating Plant, Pontederia crassipes, with Submersed Vegetation in a Shallow Lake.

The potential for a non-native plant species to invade a new habitat depends on broadscale factors such as climate, local factors such as nutrient availability, and the biotic community of the habitat into which the plant species is introduced. We developed a spatially explicit model to assess the risk of expansion of a floating invasive aquatic plant species (FAV), the water hyacinth (Pontederia crassipes), an invader in the United States, beyond its present range. Our model used known data on growth rates and competition with a native submersed aquatic macrophyte (SAV). In particular, the model simulated an invasion into a habitat with a mean annual temperature different from its own growth optimum, in which we also simulated seasonal fluctuations in temperature. Twenty different nutrient concentrations and eight different temperature scenarios, with different mean annual amplitudes of seasonal temperature variation around the mean of the invaded habitat, were simulated. In each case, the ability of the water hyacinth to invade and either exclude or coexist with the native vegetation was determined. As the temperature pattern was changed from tropical towards increasingly cooler temperate levels, the competitive advantage shifted from the tropical FAV to the more temperate SAV, with a wide range in which coexistence occurred. High nutrient concentrations allowed the coexistence of FAV, even at cooler annual temperatures. But even at the highest nutrient concentrations in the model, the FAV was unlikely to persist under the current climates of latitudes in the Southeastern United States above that of Northern Alabama. This result may have some implications for where control efforts need to be concentrated.

Assessing the effects of Water hyacinth proliferation on biochemical oxygen demand with operational land imager data

The rapid proliferation of water hyacinth (Eichhornia crassipes) in water bodies poses a significant threat to ecosystems and communities that rely on these resources. While this plant can offer certain benefits, its excessive growth can lead to detrimental ecological and social impacts. This study aimed to assess the relationship between water hyacinth coverage and Biochemical Oxygen Demand (BOD) levels in the Sonso Lagoon, Colombia, using Landsat 8 satellite imagery and in-situ measurements. Water hyacinth coverage was classified and quantified from Landsat 8 images. These data were then correlated with BOD levels obtained through periodic monitoring of the lagoon. The analysis revealed a strong negative correlation (ρ=−0.83; p−value<0.05**) between water hyacinth coverage and BOD, demonstrating the plant's impact on water quality. A predictive model was developed to estimate BOD levels based on satellite-derived water hyacinth data. The integration of remote sensing and in-situ measurements offers an effective strategy for monitoring water hyacinth proliferation and its ecological consequences. The proposed approach enables rapid assessment of water quality parameters, facilitating timely implementation of mitigation and control measures. This methodology can be extended to quantify other invasive aquatic plant species and their impacts on aquatic ecosystems.

Changes in perceived risk and ecosystem services after herbicide use on an aquatic invader

ABSTRACT Biodiversity conservation can entail socially controversial management interventions such as herbicide applications to eradicate aquatic invasive plants from highly productive native ecosystems. This study used a case example of the successful eradication of Alaska’s first aquatic invasive plant, Elodea spp. from two lakes surrounded by waterfront homes with the objective to measure perceived changes in the use of the lakes by local residents. A household survey was conducted with homeowners before and after the application of herbicides to measure public attitudes and human behavior changes related to the use of herbicide. We found fears and subjective expectations of survey respondents did not match the eventually collected objective scientific data on water quality. Also, we measured a significant negative change in lake-related activities over the duration of the management intervention that is smaller compared to the reduced activity level lake residents anticipated before the application of herbicide. Swimming and the consumption of fish caught in the lakes were the most negatively affected ecosystem services. The study showed the indirect and often hidden effects of management interventions on human risk perceptions that can translate to unintended human behavior changes and a reduction in related ecosystem service use. To account for complex social dimensions of controversial resource management interventions, resource managers require information on broad public value trade-offs and perceived risk beyond that which public meetings can provide. In this context, household surveys before and after resource management interventions can offer insights few other approaches can. The potential for more advanced outreach methods is discussed.

Thin lines between native and invasive aquatic plants are common, posing challenges for response efforts

Abstract Lines separating native and invasive plant species can be thin due to close relatedness, obscured by cryptic invasions, or breached by hybridization. Past work suggests these phenomena are especially prevalent in aquatic systems. This could arise from strong filters imposed by aquatic environments magnifying the importance of ‘preadaptation’—non‐native species succeeding where closely related native species occur due to shared traits. If so, there should be stronger signals of preadaptation in aquatic than terrestrial plant invasions, with implications for management. I tested for stronger influence of preadaptation in aquatic than terrestrial invasions by comparing relatedness of invasive and native species in aquatic versus terrestrial flora of the Midwestern USA using herbarium records and taxonomic and phylogenetic analyses. I predicted that aquatic species would constitute an evolutionarily distinct subset of plants; aquatic invaders would be more closely related, taxonomically and phylogenetically, to native aquatic plants than terrestrial invaders are to their native counterparts; and aquatic invaders from the Midwest's primary donor region (the Palearctic) would be more closely related to Midwestern species than are Palearctic aquatic plants that are not invasive in the Midwest. Findings supported the evolutionary legacy of adaptation to aquatic environments being reflected in thin lines separating invasive and native aquatic plants. Aquatic species constituted an evolutionarily distinct subset of plants, and invasive aquatic plants were more closely related to native aquatic plants (taxonomically and phylogenetically) than terrestrial invaders were to terrestrial native species. Additionally, aquatic plants of the Palearctic that are invasive in the Midwest were more closely related to Midwestern natives (phylogenetically, but not taxonomically) than were their non‐invasive counterparts, reinforcing the role of preadaptation. Synthesis and applications: Thin lines separating native from invasive aquatic plants pose challenges for response efforts. For resource managers, the prevalence of cryptic invasions requires dedicated, robust approaches to surveillance. For outreach, finer distinctions between native and invasive necessitate nuanced approaches to communication and education. And when control is needed, it should be implemented cautiously to minimize nontarget impacts to close native relatives, but thoroughly enough to prevent native relatives being displaced by competition and/or introgression.

Evaluation of Two Ecosystem Services Provided by a Pistia stratiotes Population on the Pacific Coast of South America.

One of the most fascinating wetlands on Peru's central coast is the Santa Rosa wetland (Chancay, Lima), an ecosystem threatened by anthropogenic activities. Some of these impacts have led to the uncontrolled growth of Pistia stratiotes, an invasive aquatic plant. This study sought to quantify the regulation and provisioning of ecosystem services provided by P. stratiotes using carbon storage and the provision of biomass as indicators. To this end, the biomasses of 50 plots measuring 0.0625 m2 were weighed and georeferenced and the percentages of dry biomass (%DB) and total organic carbon in the biomass (%C) were quantified. The biomass and its coordinates were entered into ArcGIS and a Kriging interpolation technique was applied to determine the total amount of biomass (B). It was found that P. stratiotes stored 3942.57 tCO2 and that 2132.41 tons of biomass could be obtained for fodder. The total carbon stored by this aquatic plant represented 28.46% of the total carbon sequestered in the wetland ecosystem by vascular plants, suggesting that its contribution to the carbon cycle is significant. This is the first study to estimate the biomass of a floating aquatic plant population in a coastal Peruvian wetland and is a pioneering study addressing the in situ carbon estimation of Peruvian floating aquatic plants. The results and methods proposed in this research will serve in the evaluation of the potential of ecosystem services among similar populations of floating aquatic species. In addition, the data presented can be used to establish plans for the management and use of this biomass in the production of soil fertilizers and cattle forage.

Functional traits of exotic submerged macrophytes mediate diversity-invasibility relationship in freshwater communities under eutrophication

Plant diversity may respond differently in terms of whether it can drive plant invasions in freshwater ecosystem. Linkages and interactions between diversity and invasibility have not been clearly resolved, and it is unclear how nutrient enrichment (e.g., eutrophication) will affect this relationship. As a key predictor of plant growth, the ability of functional traits to mediate trade-offs in the diversity-invasibility relationship is unknown. Here, we conducted a series of experiments to determine the role of exotic plant functional traits in the diversity-invasibility relationship of submerged macrophyte communities under eutrophication. We selected common native and exotic submerged macrophytes in the subtropics to construct different diverse submerged macrophyte communities to simulate invasion. Meanwhile, to test the adaptability and importance of functional traits, we experimentally verified the differences in functional traits between exotic and native species. Our results showed a positive correlation between native plant diversity and community invasibility. Moreover, the invader's performance was predominantly determined by functional traits of exotic species, such as plant biomass and tissue nutrients, which were significantly altered by species diversity. Furthermore, our results suggested that functional traits contribute significantly more to the invasiveness of exotic submerged macrophytes than the other factors to which they are subjected. Plant functional traits can mediate the diversity–invasibility relationship because of the higher intrinsic dominance of exotic submerged macrophyte species. In summary, our study revealed diversity-invasibility relationship in submerged macrophyte communities and highlighted functional traits as key drivers of invasion of high-risk exotic submerged macrophyte species. Although previous studies have elucidated the importance of functional trait studies for plant invasions, our study provides the only current evidence demonstrating the important role of invaders' functional traits in mediating the diversity-invasibility relationship. This novel perspective offers valuable insights into the management and control of invasive aquatic plants.

Global impact of water hyacinth (Eichhornia Crassipes) on rural communities and mitigation strategies: a systematic review.

The proliferation of water hyacinths (Eichhornia crassipes), recognized as one of the most invasive aquatic plants worldwide, presents profound ecological and socioeconomic challenges across diverse ecosystems, particularly in rural communities. This systematic review examines the extensive global impacts and explores various mitigation strategies to manage and utilize this pervasive species. Ecologically, water hyacinth disrupts aquatic ecosystems by depleting oxygen levels, obstructing sunlight, and displacing native species, which in turn compromises water quality and biodiversity. Economically, its rapid spread affects agriculture, fishing, and navigation, imposing significant costs on local economies and livelihoods. In response, this review assesses integrated management approaches combining mechanical, chemical, and biological controls that have been implemented to curb its growth. Moreover, innovative strategies that repurpose the biomass for bioenergy, handicrafts, and bio-remediation are discussed, highlighting their potential to transform an ecological menace into an economic resource. These strategies not only mitigate the plant's negative impacts but also contribute to sustainable development by providing economic opportunities and enhancing ecosystem services. This review stresses the necessity for a holistic approach to water hyacinth management that is adaptive, sustainable, and beneficial to affected communities.

Modeling water hyacinth (Eichhornia crassipes) distribution in Lake Tana, Ethiopia, using machine learning

Aquatic invasive plant, water hyacinth poses serious environmental and socioeconomic challenges. Understanding and predicting the spatiotemporal distribution of this species is important for reducing its environmental impact. Therefore, the present study aimed to model the distribution of water hyacinths in an important ecological region (Lake Tana) of Ethiopia using four machine learning models. We used 11 variables obtained from Sentinel-1 SAR bands, Sentinel-2A bands and indices, and bioclimate data sources. The models use 458 presence and 458 randomly generated pseudoabsence data as response variables and employ a tenfold bootstrap sampling method. The area under the curve (AUC), receiver operator curve (ROC), true skill statistics (TSS), coefficient of rank correlation (COR), sensitivity, specificity, and kappa coefficient were used to evaluate the models. The findings demonstrate that the random forest model outperforms the other models, with AUC values of 0.93 and 0.95, TSS values of 0.77 and 0.82, and kappa values of 0.76 and 0.82 in the wet and dry seasons, respectively. B12 (16% and 20%), NDWI (15% and 12%), mean annual temperature (13% and 14%), and B5 (11% and 12%) were found to be the most relevant variables during the wet and dry seasons, respectively. Water hyacinths have greater spatial coverage during the wet season than during the dry season because of high rainfall, high water levels and nutrient runoff. We can conclude that to detect and predict the spatiotemporal conditions of water hyacinth accurately, integrating Sentinel image indices and bands with bioclimatic variables and using machine learning models are crucial.

Investigating UV-Irradiation Parameters in the Green Synthesis of Silver Nanoparticles from Water Hyacinth Leaf Extract: Optimization for Future Sensor Applications.

Silver nanoparticles (AgNPs) can be produced safely and greenly using water hyacinth, an invasive aquatic plant, as a reducing agent. This study aimed to optimize the UV-irradiation parameters for the synthesis of AgNPs from water hyacinth leaf extract. The study varied the reaction time and pH levels and added a stabilizing agent to the mixture. The synthesized AgNPs were characterized using UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The findings revealed that the optimal conditions for synthesizing AgNPs were achieved by adjusting the pH level to 8.5, adding starch as a stabilizing agent, and exposing the mixture to UV-A radiation for one hour. These conditions resulted in the smallest size and highest quantity of AgNPs. Furthermore, the synthesized AgNP colloids remained stable for up to six months. This study highlights the potential of utilizing water hyacinth as a sustainable and cost-effective reducing agent for AgNP synthesis, with potential applications in pharmaceuticals, drug development, catalysis, and sensing detection.

Ecology of Elodea canadensis Michx. and Elodea nuttallii (Planch.) H. St. John-Insights from National Water Monitoring in Croatia.

Elodea canadensis Michx. (common waterweed) and Elodea nuttallii (Planch.) H. St. John (Nuttall's waterweed), two invasive aquatic plants from North America, have coexisted in European water bodies since the early 20th century. New localities for both species in Croatia continued to be discovered during a study that ran from 2016 to 2023 as a part of the annual implementation of Water Framework Directive monitoring that covered the entire territory of Croatia (786 sampling points in total). Based on these data, the distribution and ecology of both species were analysed. Elodea canadensis was found at 30 sampling points, mostly in rivers, and E. nuttallii at 15 sampling points, mostly in artificial canals. Nearly three-quarters (72.5%) of all elodea sampling points were in the Pannonian Ecoregion. Elodea canadensis was discovered for the first time in the Continental-Dinaric and Mediterranean-Dinaric Subecoregions. To study the ecology of the species, for each sampling point, vegetation relevés were performed and monthly measurements of physico-chemical parameters were collected. The most common accompanying species for both elodeas are presented, and the difference in species assemblages between the sites with E. canadensis and E. nuttallii was confirmed with the ANOSIM test. Furthermore, Indicator Species Analysis revealed eight species characteristic of E. canadensis sites and eleven species characteristic of E. nuttallii sites. Fitting multivariate models (CCA and NPMR) to species abundance revealed the ecological reaction of E. canadensis and E. nuttallii to environmental descriptors. The most strongly contributing environmental descriptors that influence the distribution of both Elodea species are biochemical oxygen demand, electrical conductivity and total phosphorus. In Croatia, the replacement of E. canadensis with E. nuttallii was observed in several water bodies with high nutrient loads.

Invasive Aquatic Plants as Potential Sustainable Feedstocks for Biochar Production and as an Innovative Approach for Wastewater Treatment

Biochar (BC) is a well-established physical treatment method. The high-cost BC limits their use as adsorbents in wastewater. Thus, deriving BC from cheap and locally available waste materials is needed to develop a feasible waste removal technology. Nowadays, BC technology makes it possible to envision a new strategy to manage invasive plants by converting them into value-added products like BC. Hence, the present study was designed to evaluate the potential utilization of BC as an efficient filter medium made by invasive aquatic plants, Salvinia spp., and Eichhornia spp. A mass of 50 g of prepared activated and nonactivated BC was incorporated in a sand and gravel filter to treat rubber-manufactured wastewater. Wastewater was passed through the filter, and both raw and treated water samples were analyzed for pH, Total Suspended Solids (TSS), Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Total Kjeldahl Nitrogen (TKN), Ammoniacal-Nitrogen (NH3-N), Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Phosphates (TP), Nitrate (NO3-N), turbidity and heavy metals (Zinc, Chromium). The control filter was developed only with sand and gravel, excluding BC. Fourier Transform-Infrared Spectroscopy (FT-IR) and Scanning electron microscopy (SEM) were used to analyze BC’s chemical and physical characteristics. A brine shrimp lethality assay was carried out for toxicological evaluation. OH stretching (3,550-3,200 cm−1), C=C aromatic stretching (1400-1660 cm−1), and Phenol-O-H bending (1,300-1,400 cm−1) were recorded in all BC samples that involved the adsorption mechanism. Observed images indicated differences in surface morphology of both activated and nonactivated BC were observed under SEM observation. The study concludes that the filter unit incorporated with activated Eichhornia spp. Gave the best treatment efficiency when compared to filter units incorporated with other activated and nonactivated BC. The toxicity assay revealed 100% mortality in the control setup and raw wastewater but only 60–70% in the nonactivated BC integrated filters. Activated BC-incorporated filters showed no mortalities. Hence, the study’s outcomes suggest a green approach using invasive aquatic plants for sustainable wastewater treatment.

Sustainable solutions for water hyacinth invasion: Characteristics, impacts, control, and utilization

Water hyacinth (Eichhornia crassipes) is an invasive aquatic plant that has become a global issue due to its significant ecological and socio-economic impacts. This paper discusses the characteristics and impacts of water hyacinth invasion, emphasizing the urgency of effective management strategies. Various methods for harvesting and controlling water hyacinth, including physical, biological, and chemical approaches, are elucidated. Additionally, the paper highlights the potential utilization of water hyacinth for pollutant absorption and sequestration of heavy metals, organic contaminants, and excess nutrients. Furthermore, the opportunities to convert water hyacinth biomass into bioenergy sources such as biogas and bioethanol have been identified. The paper also presents the technical feasibility of using water hyacinth to produce biochar, high-quality bio-fertilizer, animal feed, and several other valuable products.

Multi-Interacting Natural and Anthropogenic Stressors on Freshwater Ecosystems: Their Current Status and Future Prospects for 21st Century

The inheritance of historic human-induced disruption and the fierceness of its impact change aquatic ecosystems. This work reviews some of the main stressors on freshwater ecosystems, focusing on their effects, threats, risks, protection, conservation, and management elements. An overview is provided on the water protection linked to freshwater stressors: solar ultraviolet radiation, thermal pollution, nanoparticles, radioactive pollution, salinization, nutrients, sedimentation, drought, extreme floods, fragmentation, pesticides, war and terrorism, algal blooms, invasive aquatic plants, riparian vegetation, and invasive aquatic fish. Altogether, these stressors build an exceptionally composite background of stressors that are continuously changing freshwater ecosystems and diminishing or even destroying their capability to create and maintain ongoing natural healthy products and essential services to humans. Environmental and human civilization sustainability cannot exist without the proper management of freshwater ecosystems all over the planet; this specific management is impossible if the widespread studied stressors are not deeply understood structurally and functionally. Without considering each of these stressors and their synergisms, the Earth’s freshwater is doomed in terms of both quantitative and qualitative aspects.

Research on Satellite and Ground Multi-Sensor Collaborative Sensing Method for Floating Plants

Abstract. Dynamic monitoring of water environment is the basis of maintaining urban security and promoting urban sustainable development. To effectively solve the problems caused by the large-scale flooding of floating aquatic invasive plants, such as water environment destruction, clogging river, water quality pollution, water ecological balance destruction, etc., a satellite and ground multi-sensor collaborative sensing method for floating plants is proposed in this paper. For the monitoring of floating plants in macro watershed, the vegetation index and chlorophyll concentration were used to extract floating plants, analyzing, and calculating the distribution and coverage area of floating plants based on 4-band high-resolution satellite images. For the monitoring of floating plants in small watershed, combined with visible light video, multispectral images, and LiDAR data, optimized spectral feature variable processing, semantic segmentation network, and symmetric function neural network are utilized to obtain real-time information on the invasion location, distribution pattern, and coverage area of floating plants. In this paper, the upstream basin of the Huangpu River in Shanghai in 2023 was selected as the experimental area. The distribution of floating plants in different watercourse and different periods was successfully obtained by this method, and the coverage area was accurately calculated with an identification rate of more than 90%, which provided technical support for cross-regional management and efficient cleaning of floating plants.