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The dye removal using phytoremediation has demonstrated its potential to degrade many recalcitrant dyes. The kinetic investigations for phytoremediation ability of Salvinia molesta Mitchell (S. molesta) were evaluated for Direct Red 28 (DR28) dye in the present research work. The potential of S. molesta was analysed at different pH and different initial dye concentrations. About 90 % of dye decolorization was achieved for 50 mg L−1 dye solution with 4 g of S. molesta plant at pH 6.5. The experimental results were evaluated with pseudo-first, pseudo-second and Elovich kinetic models. The validation indicated the most suitable curve with Pseudo-second order having the correlation value R2 ≥ 0.99. FTIR studies supported the phytoextraction of DR28 through functional group interaction between plant hairy roots and dye molecules. The results of the present studies suggests that S. molesta can be utilized for remediation of water bodies and wetlands contaminated with dye wastewater in natural conditions.

Additional active ingredients are needed for use in aquatic systems to respond to new threats or treatment scenarios, enhance selectivity, reduce use rates, and mitigate the risk of herbicide resistance. Florpyrauxifen-benzyl is a new synthetic auxin developed for use as an aquatic herbicide. A study was conducted at North Carolina State University in which 10 µg L−1 of 25% radiolabeled florpyrauxifen-benzyl was applied to the isolated shoot tissue of 10 different aquatic plant species to elucidate absorption and translocation patterns in these species. Extremely high levels of shoot absorption were observed for all species, and uptake was rapid. Highest shoot absorptions were observed for crested floatingheart [Nymphoides cristata (Roxb.) Kuntze] (A192 = 20 µg g−1), dioecious hydrilla [Hydrilla verticillata (L. f.) Royle] (A192 = 25.3 µg g−1), variable watermilfoil (Myriophyllum heterophyllum Michx.) (A192 = 40.1 µg g−1), and Eurasian watermilfoil (Myriophyllum spicatum L.) (A192 = 25.3 µg g−1). Evidence of translocation was observed in all rooted species tested, with the greatest translocation observed in N. cristata (1.28 µg g−1 at 192 h after treatment). The results of this study add to the growing body of knowledge surrounding the behavior of this newly registered herbicide within aquatic plants.

Eichhornia crassipes and Salvinia molesta are two of the world’s worst aquatic invasive alien plant Species (AIAPS) that have a major impact on the environment, agricultural production and food security. The aim of this study was to understand the current and potential distribution of E. crassipes and S. molesta under climate change in the tropical island of Sri Lanka. The MaxEnt species distribution modelling technique was used to generate predictive models using global distribution data and environmental variables. For future projections, the mean of two best performing climate models was used under two emissions scenarios, Representative Concentration Pathways (RCP) 4.5 and 8.5 for time periods 2050 and 2070. The study revealed that at present, the majority of the aquatic habitats of the country, particularly lowland areas, are vulnerable to the invasion of these two species; however, a striking difference was observed under future RCP scenarios. Aquatic habitats suitable for E. crassipes is predicted to decrease substantially by 2050 and increase again until 2070. The suitable habitats of S. molesta are likely to decrease sharply until 2070. This study provides insights for decision-makers that climate change influences should be considered for long-term management of AIAPS.

The non-native aquatic fern giant salvinia, Salvinia molesta Mitchell (Salviniaceae), poses a risk to freshwater ecosystems through limiting light penetration, decreasing submerged aquatic vegetation (SAV) abundance, altering water quality, and potentially leading to changes in macroinvertebrate community structure. Here, we conducted repeated quarterly field surveys and measured light, nutrients, water quality, and aquatic macroinvertebrate community composition and energetic value to detect effects from giant salvinia invasion. Giant salvinia reduced dissolved oxygen, pH and light availability in the aquatic environment, and increased the concentration of orthophosphate and ammonium. Following initial colonization, macroinvertebrate communities in giant salvinia resembled SAV communities dominated by aquatic insects, however, richness and relative abundance in giant salvinia decreased over time, resulting in a community populated by few taxa, primarily crustaceans. Total macroinvertebrate energetic value in giant salvinia was significantly lower than SAV communities. Giant salvinia invasion changed habitat composition, triggered internal nutrient loading, and reduced macroinvertebrate abundance, diversity, and ecosystem productivity. Our findings demonstrate larger ecological impacts from giant salvinia than previously reported, including potential disruption to the transfer of energy between trophic levels.

Invasion from giant salvinia (Salvinia molesta Mitchell, Salviniaceae) blocks sunlight entering waterbodies, reducing submerged aquatic macrophytes, thus lowering dissolved oxygen and stressing aqu...

The objective of this study was to investigate the reduction of phosphorus from rice mill wastewater by using free floating aquatic plants. Four free floating aquatic plants were used for this stud...

Biomimetic superhydrophobic surfaces display many excellent underwater functionalities, which attribute to the slippery air mattress trapped in the structures on the surface. However, the air mattress is easy to collapse due to various disturbances, leading to the fully wetted Wenzel state, while the water filling the microstructures is difficult to be repelled to completely recover the air mattress even on superhydrophobic surfaces like lotus leaves. Beyond superhydrophobicity, here we find that the floating fern, Salvinia molesta, has the superrepellent capability to efficiently replace the water in the microstructures with air and robustly recover the continuous air mattress. The hierarchical structures on the leaf surface are demonstrated to be crucial to the recovery. The interconnected wedge-shaped grooves between epidermal cells are key to the spontaneous spreading of air over the entire leaf governed by a gas wicking effect to form a thin air film, which provides a base for the later growth of the air mattress in thickness synchronously along the hairy structures. Inspired by nature, biomimetic artificial Salvinia surfaces are fabricated using 3D printing technology, which successfully achieves a complete recovery of a continuous air mattress to exactly imitate the superrepellent capability of Salvinia leaves. This finding will benefit the design principles of water-repellent materials and expand their underwater applications, especially in extreme environments.

We investigated the effect of CO2 and nutrient enrichment on competition between two free-floating fern species that co-occur in south-eastern Australia—native Azolla filiculoides and invasive exotic Salvinia molesta. The species were grown in monoculture and competition in a glasshouse experiment where the nutrient medium was replaced weekly to simulate a dynamic system. We found that the relative growth rate (RGR) of both species was greater under high resource conditions, with neither showing a suppressive response due to competition. On the contrary, A. filiculoides had a facilitative effect on S. molesta. In addition, A. filiculoides gained more biomass under high resource conditions relative to S. molesta and the opposite was true under low resource conditions. We conclude that [CO2] and nutrient concentration did not mediate competition between the species but instead influenced RGR independent of competition. These findings suggest that species composition in dynamic water bodies under future conditions may be determined by the species’ responses to environmental changes rather than by changes in competitive interactions.

We compared the cold tolerance of three populations of the salvinia weevil, Cyrtobagous salviniae. When exposed to 0°C, lethal time to kill 90% of adults from the Bayou Nicholas population ...

Rising atmospheric CO2 concentration is one of the most important ways human activity is contributing to global change. It has led to climate-related changes that affect physiological performance, phenology, and distributions of species globally. Elevated [CO2] enhances growth in many plant species through increased photosynthetic rates, improved water and nitrogen use efficiency, and altered functional traits. In this study, we investigated the growth, reproduction and functional trait responses to elevated [CO2] of two free-floating ferns, the native Azolla filiculoides (Azollaceae) and the exotic invasive Salvinia molesta (Salviniaceae), and a submerged native angiosperm, Vallisneria spiralis (Hydrocharitaceae). The species were grown in monocultures under ambient (∼400 ppm) and elevated (∼600 ppm) [CO2] in a greenhouse experiment. We found that A. filiculoides had enhanced relative growth rate and reproduction under elevated [CO2]. However, its root to shoot ratio was unaffected while its specific leaf area was reduced under elevated [CO2]. In contrast, S. molesta and V. spiralis did not differ in their growth, reproduction or functional trait responses between the CO2 treatments. We conclude that freshwater plant responses to elevated [CO2] may vary across species, with functional differences potentially driving differential responses as exemplified by the lack of response of the CAM physiology species Vallisneria spiralis and the strong response of the nitrogen-fixing A. filiculoides compared to the non nitrogen-fixing species in this study. Future work should focus on the impact of elevated CO2 on plant growth in the context of environmental conditions such as pH, temperature and light availability in freshwater systems.

Aquatic insects are important to the transfer of energy in freshwater wetlands. They link primary producers and organic matter to higher trophic levels, and pass energy from the aquatic environment to the terrestrial ecosystem via predation of adults. Introduction of the invasive free-floating aquatic fern giant salvinia, Salvinia molesta Mitchell, threatens aquatic insect communities and life cycle completion, specifically colonization, through mat formation and habitat changes. We examined how aerial colonization and assemblage structure of aquatic insects were affected by giant salvinia coverage. Mesocosms were established with three giant salvinia coverages, 25%, 50%, and 100%, and a native submerged macrophyte, 0% coverage; and environmental conditions and community structure were sampled monthly, over four months. After four weeks, all giant salvinia coverages reduced dissolved oxygen, pH, and light availability in the aquatic environment. In the 100% cover treatment, aquatic insect colonization was impeded, resulting in communities with lower abundance and richness, which were dominated by a coleopteran. The 25% and 50% giant salvinia coverages changed habitat complexity, which yielded different aquatic insect communities from the 0% and from 100% coverages. Regardless of the coverage, giant salvinia changed environmental conditions and putatively the 100% coverage disrupted the aquatic insect life cycle by limiting aerial colonization. This inability to complete their life cycle means aquatic insects cannot replenish themselves, leading to a diminished species pool and reduced energy potential. Our results highlight new, previously unreported, negative impacts from giant salvinia on ecosystem structure and function.

Organic matter, nutrients, and chemicals are some of the waste materials found in most domestic wastewaters. The purpose of this research was to evaluate the potentials of Pistia stratiotes, Salvinia molesta, and Eichhornia crassipes aquatic weed plants in the tertiary treatment of secondary domestic wastewater using hydroponic systems. Physicochemical analysis that considered turbidity, phosphate, ammoniacal nitrogen, and nitrate was conducted on the wastewater samples at different retention times of 6, 12, and 24 h for 14 days. The best performance was observed for a 24 h retention treatment system, with up to 91% (P. stratiotes), 94% (S. molesta), and 89.3% (E. crassipes) reduction for turbidity, 81.2% (P. stratiotes), 82.7% (S. molesta), and 88.5% (E. crassipes) for phosphate reduction, 88.66% (P. stratiotes), 90.47% (S. molesta), and 89.11% (E. crassipes) for ammoniacal nitrogen reduction, 83.6% (P. stratiotes), 92.1% (S. molesta) and 93% (E. crassipes) for nitrate reduction. Hence, the application of hydroponic systems in cultivation of the macrophytes proved to be effective in the phytoremediation process by removing the residual nutrients present in the treated secondary domestic wastewater. Additionally, this method can be used for the cultivation of plant-based biomass and other non-edible useful crops using the free nutrients content of the wastewater before its discharge into the natural environment.

Aquaculture is an activity with economic and social importance since it generates food, employment, and income. However, like other human activities, it negatively impacts the environment, in this respect mainly due to the production of effluents rich in sedimentable solids, organic matter, phosphorus, and nitrogen. These last two are responsible for the eutrophication of water courses, causing changes in the aquatic biota. Hence, there is a need to adopt strategies to improve the efficiency of wastewater reuse. In this sense, the objective of this work was to evaluate the efficiency of using the floating aquatic macrophytes Eichhornia crassipes, Pistia stratiotes, and Salvinia molesta for the treatment of aquaculture effluents. The experiment was conducted in a completely randomized design, with seven treatments and three repetitions; the treatments were the following: T1, without plant, treated only with sedimentation; T2, Eichhornia crassipes; T3, Pistia stratiotes; T4, Salvinia molesta; T5, Eichhornia crassipes and Pistia stratiotes; T6, Eichhornia crassipes and Salvinia molesta; and T7, Pistia stratiotes and Salvinia molesta. The treatments were evaluated for a period of 168 h: the first collection of effluent allowed analysis of the raw effluent; the second occurred 24 h after the first collection and the others, on alternate days with 72, 120, and 168 h, totaling five collections in each experimental unit. The effluent used came from breeding tanks of Nile Tilapia (Oreochromis niloticus). The quality of the effluent was evaluated by the rate of removal of nutrients N-total, N-nitrite, N-nitrate, N-ammoniacal and Ptotal, temperature, pH, turbidity, dissolved oxygen, electrical conductivity, total alkalinity, BDO, and CDO. After the effluent was treated, the values of the parameters were compared with the maximum admissible values (MAVs), as specified by Brazil's National Environmental Council (CONAMA) in Resolutions 430/2011 and 357/2005. With the use of floating aquatic macrophytes, the concentrations of all evaluated limnology parameters improved significantly. There was also an improvement in the physical aspect of the effluent (transparency and turbidity). Thus, it can be concluded that the use of the macrophytes Eichhornia crassipes, Pistia stratiotes, and Salvinia molesta is effective in the treatment of effluents from fish farming.

Salvinia molesta D.S. Mitchell (Salviniaceae) is a damaging free-floating invasive alien macrophyte native to South America. The biological control programme against S. molesta by the weevil Cyrtobagous salviniae Calder and Sands (Erirhinidae) has been successful in controlling S. molesta infestations in the introduced range, however, there is some debate as to how biological control success is measured. This study measured the response of epilithic algae and aquatic macroinvertebrate communities in a S. molesta-dominated state and subsequently where the weed had been cleared by biological control, as a proxy for ecosystem recovery in a before&ndash, after control&ndash, impact mesocosm experiment. The restored treatment (S. molesta and C. salviniae) demonstrated epilithic algae and aquatic macroinvertebrate recovery during the &ldquo, after&rdquo, biological control phase, defined as similar to the control treatment. Comparatively, the impacted treatment (100% S. molesta) showed a drastic decline in biodiversity and shifts in community assemblages. We conclude that the biological control effort by C. salviniae facilitated biodiversity recovery of the impacted treatment. Furthermore, epilithic algae and aquatic macroinvertebrate communities were reliable biological indicators for measuring ecological impacts of invasion and ecosystem recovery following biological control, and thus represent potential tools for evaluating biological control success and ecological restoration.

Nutrient status of freshwater ecosystems has a significant influence on biological invasions, species richness and community structure. The role of phosphorus in driving these effects has been widely reported while its co-limitation with nitrogen and other elements has received more recent attention. In a greenhouse experiment, we investigated the growth responses of two invasive exotic (Egeria densa and Salvinia molesta) and one native (Vallisneria spiralis) freshwater plant species to additional low concentrations of nitrate nitrogen (N-NO3). The species were grown at five nitrate concentrations (0.02, 0.05, 0.1, 0.5, and 0.9 mg N-NO3 L−1). We found that the growth of E. densa and V. spiralis increased with increasing nitrate concentration. Surprisingly, S. molesta had the fastest growth rate at the midrange nitrate concentration of 0.1 mg N-NO3 L−1 and its leaf production was not affected by nitrate treatment. Irrespective of nitrate concentration, the invasive exotic species, particularly S. molesta, showed much greater growth responses than the native V. spiralis. We conclude that freshwater plant growth responses to low nitrate concentrations will be species specific but the faster growth rates of S. molesta provide an example of how differences between co-occurring invasive exotic species and native species could have profound effects on the structure and function of freshwater ecosystems under changed environmental conditions.

Antioxidant enzymes are important components in the defense against arsenic (As) stress in plants. Here, we tested the hypothesis that Salvinia molesta, an aquatic fern, counteracts the harmful arsenite (AsIII) effects by activating scavenging reactive oxygen species (ROS) enzymes. Thus, our objective was to investigate the role of the superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and ascorbate peroxidase (APX) in S. molesta tolerance to AsIII and indicate the use of this plant in remediation of contaminated water. Plants were grown in nutrient solution at pH 6.5 and exposed to 0, 5, 10, or 20 µM AsIII for 96 h (analyses of As absorption, mineral nutrient content, and relative growth rate) and for 24 h (analyses of oxidative stress indicators and enzymatic antioxidant defenses). In the floating leaves, there was a greater basal activity of the antioxidant enzymes and less accumulation of As than in submerged leaves. The submerged leaves, which function as roots in S. molesta, accumulated more As than floating leaves, and SOD and CAT activities were inhibited. Thus, there was a greater production of ROS and oxidative stress. Our results show that S. molesta presents enzymatic antioxidant defenses to alleviate AsIII toxicity and are more effectives in the floating leaves. These results are important to elucidate the AsIII tolerance mechanisms in S. molesta and the possibility of their use in contamined water phytoremediation. Additional studies exposing plants to more prolonged stress and using AsIII concentrations closer to those found in contaminated environments will confirm this claim.

Biomethane potential (BMP) test was performed to access the anaerobic degradation of three macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta). Sonication pretreatment was evaluated in order to pre-hydrolyze the plants, aiming to remove the lag time and potentially increase the methane production. Two sonication energies were tested: 40,000 and 80,000 kJ kgTS− 1. Results indicated that not all the aquatic plants presented the same behavior. Raw biomass of Eichhornia and Pistia required a long lag-phase (11 and 8 days, respectively), while Salvinia did not, being the faster and most productive raw biomass (64% of biomethanization factor). Pretreated biomass was solubilized, however the results did not have a direct translation to the digestion performance. In fact, no substantial improvement on the amount of methane production occurred. The main experimental evidence was the full reduction of the lag-phase for Eichhornia and Pistia, while Salvinia did not exhibited a substantial change neither in methane production or in kinetics. The high biodegradability of Salvinia biomass without pretreatment indicated that ultrasound pretreatment is not required. Energetic Sustainability Index evidenced that sonication pretreatment process was not sustainable, due to the required high water content of the bulk.

The plant leaf of Salvinia molesta can retain an air layer underwater due to the hydrophobic and elastic eggbeater-shaped hairs on its surface, which have potential applications in thermal insulati...

Salvinia molesta, commonly known as giant Salvinia, is a floating fern belonging to the family of Salviniaceae. In this study the active fractions of the fern extract were separated using column chromatography and phenolic compounds present in the active fractions were determined by RP-HPLC. Ethyl acetate extract was found to possess significant pharmacological activity when compared to other extracts under study and therefore an attempt was made to fractionate ethyl acetate extract. The analysis was performed through two different mobile phases involving solvent A (acetonitrile) and solvent B (0.1% phosphoric acid in water) and solvent A (methanol) and Solvent B (4% acetic acid). HPLC analysis indicated the presence of phenolic compounds namely ascorbic acid, quercetin, gallic acid, resorcinol, catechol, vanillin and benzoic acid with specific retention times. The detected compounds possess antioxidant and antitumour activities. The results of the present study suggests the possibility to use S. molesta as a source for a plausible antioxidant agent which could be isolated and used as a lead candidate for the development of antioxidant drugs that help stop or limit damage caused by free radicals and to counteract oxidative stress leading to the prevention of a variety of chronic and degenerative diseases. Keywords: Salvinia molesta, Antioxidants, Phenolic compounds, Column chromatography, Fractionation, Free radicals

Akumulasi logam berat dan bahan pencemar ke dalam ekosistem akuatik memberi impak negatif kepada alam sekitar dan organisma akuatik. Salvinia molesta dan Pistia stratiotes merupakan spesies yang mempunyai kadar pertumbuhan yang cepat dan berkemampuan dalam mengakumulasi logam berat dan menyerap nutrien menjadikan ia sesuai digunakan untuk merawat air sisa melalui kaedah bioteknologi iaitu fitoremediasi. Kajian ini dijalankan untuk menentukan kualiti air sisa kumbahan sebelum dan selepas rawatan menggunakan kaedah fitoremediasi. Selain itu, objektif kajian ini juga adalah untuk menilai keberkesanan Salvinia molesta dan Pistia stratiotes sebagai agen fitoremediasi bagi rawatan air sisa. Sampel tumbuhan akuatik berbeza berat iaitu 10, 20 dan 30 g diuji untuk rawatan tersebut. Ujian ANOVA satu hala menunjukkan perbezaan kadar pengurangan jumlah pepejal terampai dan ammoniakal nitrogen yang bererti (p

Indian reservoir’s managers have been facing problem in managing water and fisheries resources due to invasive aquatic weed infestation. Multispectral remote sensing data was used for monitoring the growth pattern of world’s worst weed; Giant Salvinia (S. molesta Mitchell) in reservoir “Tumaria”, located in the Terai region of Uttarakhand (India). Temporal satellite data of Landsat-7 (ETM +) and Landsat-8 (OLI) for the period April, 2013 to May, 2015 were used for mapping and monitoring the weed. It was revealed that the reservoir was free from floating weed Salvinia until June, 2013 and for the first time appeared during September, 2013. It has covered 42% of the water spread area and subsequently covered 92% area until October, 2013. Active growth (matured weed) of Salvinia was observed when it covered 89–92% of water surface from October, 2013 to January, 2014 and also new growth (immatured weed) of Salvinia was observed on same months. Thematic map derived from the study can be used as a decision support tool for controlling aquatic weed infestation.

Households, food-processing industries and ponds and lakes all contribute towards waste which are usually untreated and have a unique putrescible property. These materials are low-cost lignocellulosic materials that have some prospective for reutilization. The present study provides a detailed physio-chemical characterization of commonly found waste materials such as banana (Musa) peel, banana blossom peel and most importantly Kariba Weed (Salvinia molesta) which is a type of weed found in stagnant water bodies in Kerala and thus the selection of this material also contributes towards the treatment possibilities of weed which is deemed as useless and at times contributes harmful effects when present in the ecosystem. The study includes the determination of various physico-chemical parameters such as pH , Turbidity, Electrical Conductivity, Total Solids and chemical parameters like Chloride, alkalinity, Acidity and Hardness at different conditions. In addition to all these parameters, the percentage removed is determined for a comparative study. Banana peel, Banana blossom peel and a Kariba weed are naturally occurring bio-waste materials which can offer a viable and cost effective solution for waste water treatment

Utilization of Salvinia molesta, an aquatic weed which is notorious for its allelopathy and invasiveness, has been explored by its vermicomposting. Fourier transform infrared spectroscopy (FT-IR) and plant bioassay tests were conducted to analyze the composition and fertilizer value of S .molesta vermicompost. Germination and seedling growth tests were performed in soil supplemented with vermicompost at levels ranging from 0.75 to 40% by weight of the soil on three common food plants, ladies finger (Abelmoschus esculentus), cucumber (Cucumis sativus), and green gram (Vigna radiata). The influence of S. molesta's vermicompost on some of the physicochemical and biological attributes of the soil was also studied. FT-IR analysis revealed that S. molesta loses its allelopathy, as the chemical compounds that are responsible for it are largely destroyed, in the course of its vermicomposting. There is also an indication that a portion of lignin content of S. molesta is degraded. Vermicompost enhanced the germination success and promoted the morphological growth and biochemical content of the plant species studied. It also bestowed plant friendly physicochemical and biological attributes to the soil. The findings raise the prospect that billions of tons of S. molesta biomass-which not only goes to waste at present but is also a cause of serious harm to the environment-may become utilizable in organic agriculture.

Purpose In a novel attempt, vermicompost derived from an intransigent and noxious weed salvinia was assessed for its fertilizer value and pest repellent properties. Methods In outdoor experiments which simulated the way vegetables are cultivated by farmers, ladies finger (Abelmoschus esculentus) seeds were germinated and grown in soil supplemented with salvinia vermicompost at four levels: 0 (V0), 2.5 (V1), 3.75 (V2) and 5 (V3) t/ha. Besides assessing germination success and subsequent growth, yield, and biochemical content of the plants, the impact of pest attacks on them was also studied. Results Salvinia vermicompost significantly enhanced germination success, growth, and yield of the plants. Maximum growth in terms of shoot length (96.2 cm), root length (48.2 cm), shoot and root dry weight (23.31, 7.96 g), stem diameter (14.04 mm), and number of leaves and branches (26.8, 4.8) was recorded in V4 (5t/ha). Likewise, the mineral and biochemical content in vermicompost-treated plants was significantly higher than in the controls. The vermicompost also induced resistance in plants against pests and disease. Compared to the controls, vermicompost had reduced the fruit borer infection by 65, 78 and 82% in V1, V2 and V3, respectively. Conclusion The toxicity of salvinia is largely eliminated when it is vermicomposted, and the product acquires the qualities of a good organic fertilizer. The present work can potentially lead to the development of an inexpensive, sustainable and eco-friendly method of utilizing billions of tons of phytomass that is generated annually by salvinia, and which presently goes to waste.

Cyrtobagous salviniae is widely used in several countries including the United States, South Africa and Australia for biological control of Salvinia molesta Mitchell (Salviniales: Salviniaceae). Despite considerable success in tropical and subtropical regions, the effectiveness of C. salviniae on S. molesta is inconsistent in temperate regions, indicating the need for populations adapted to cooler climates. The objectives of this study were to determine the regions of South America that are climatically similar to S. molesta habitats in temperate Louisiana, conduct surveys for new provenances of C. salviniae in these regions, establish the phylogenetic relationships among C. salviniae provenances, and compare the cold tolerance of populations of C. salviniae from Louisiana, USA and the Lower Parana-Uruguay Delta (LPUD), South America. Foreign exploration of the Lower Parana-Uruguay Delta region resulted in the first record of C. salviniae in Uruguay, and revealed the most southern distribution of this species in Argentina and Uruguay. Phylogenetic identification of this provenance indicated that it is a different biotype to the one from Brazil which was first released in the United States in 2001. Analysis of the climate in south, central, and north Louisiana revealed colder and more frequent cold fronts in the north, likely contributing to winter population crashes. Regional differences in Louisiana thermal regimes indicate that there is a need for region specific management plans, such as the inclusion of cold tolerant C. salviniae populations in the management of S. molesta in temperate regions. The cold tolerance of C. salviniae populations from Louisiana and Lower Parana-Uruguay Delta were compared by measuring survival at 0 °C, chill coma recovery times, and supercooling points (SCP). Survival at 0 °C was 1.5-times greater, mean chill coma recovery time was 1.8-times faster, and mean SCP was 1.2-times lower in the Lower Parana-Uruguay Delta population compared to the Louisiana population. These findings show that the Lower Parana-Uruguay Delta provenance should be considered for managing S. molesta in temperate regions. Besides host range tests on the Lower Parana-Uruguay Delta biotype, cross breeding between the Louisiana and Lower Parana-Uruguay Delta populations of C. salviniae should be investigated to determine the life histories of any possible hybrids.

In natural biological treatment systems, floating macrophytes have been used in maturation pond in recent years to upgrade effluents from stabilization ponds and are to achieve secondary treatment effluent quality from primary sewage effluent. In this study, the performance of phytoremediation by Salvinia molesta macrophytes on treated Palm Oil Mill Effluent (POME) is investigated. The objectives of the study are to determine the nutrient uptake by S. molesta from treated POME and its effect towards the biomass and biochemical content. The water quality after phytoremediation were monitored. The wastewater phytoremediation by S. molesta was conducted outdoor for 16 days in a raceway pond rig. The results showed that S. molesta achieved 95% phosphate removal efficiency from the wastewater, lowering concentration to 0.17 mg/l. Nitrate concentration was determined to be at 0.50 mg/l at the end of the experiment. Ammonia concentration showed a dynamic fluctuation trend with average value of 2.62 mg/l. For water quality assessment, turbidity decreased from 7.56 NTU to 0.94 NTU in just 2 days’ time. MLVSS analysis was significantly low by day 2 of experiment. COD removal efficiency was determined at 39%. All six water quality assay met their respective statutory discharge limit. The S. molesta cultivated in the raceway pond rig also showed increment toward the biomass gain, carbohydrate and protein at the end of the experiment. This study indicates that S. molesta plants have the potential to be used in the phytoremediation of treated POME and showed a superior biochemical composition.

Phytoremediation of industrial sewage sludge with Eichhornia crassipes, Salvinia molesta and Pistia stratiotes in pilot scale batch fed free water flow constructed wetlands was done in order to assess the suitability of remediated sludge as fertilizer. S. molesta showed the greatest decreases of Zn (36.0%), Fe (26.6%), Cu (32.6%), Cr (58.6%) and Ni, (26.9%) while P. startiotes and E. crassipes, respectively, showed the greatest Cd (27.1%) and Pb (42.4%) decreases. Metals, nutrients (total N and P) and fecal coliform in remediated sludge complied with regulatory standards and P. startiotes showed the greatest electrical conductivity (EC) (65.6%) decrease. The phytotoxicity assay on Lactuca sativa and Brassica oleraceae exhibited more than 50% of germination index from the sludge remediated with S. molesta. The results demonstrate that phytoremediation with hyper accumulators followed by phytotoxicity assay could be used to support decisions for the appropriate use of land disposed industrial sewage sludge.

Salvinia molesta (Giant Salvinia) is a highly problematic, non-native, invasive species in the southeastern United States. Other than introduced biological control agents, observations of natural enemies to Giant Salvinia are rare within the United States. We observed a native crayfish, Procambarus clarkii (Red Swamp Crayfish), feeding on Giant Salvinia in outdoor ponds that are typically utilized for mass-rearing Cyrtobagous salviniae (Salvinia Weevil), a Giant Salvinia biological control agent. Red Swamp Crayfish consumed the roots and leaves of Giant Salvinia, which greatly reduced its biomass. To our knowledge this is the first documented observation of the Red Swamp Crayfish consuming Giant Salvinia. This observation increases our knowledge about species that can consume Giant Salvinia and is a potential new pest of concern for managers of Salvinia Weevil rearing operations.

BACKGROUND: Methyl benzoate (MB) is a small, hydrophobic organic compound isolated from the freshwater fern Salvinia molesta (Salviniales: Salviniaceae). It is used as a fragrance and flavor enhancer owing to its pleasant smell. It has also demonstrated potential as a green pesticide for various groups of insects. However, its effects on mites are yet to be studied. RESULTS: Here, we assessed the acaricidal and repellent effects of MB against the two‐spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), under laboratory and greenhouse conditions. MB demonstrated concentration‐dependent contact toxicity against eggs and adults of the mite. A leaf‐dipping assay using 1% MB prevented the hatching of 92.7% of eggs and killed 100% of adults within 48 h of treatment. Concentration–mortality statistics were subjected to probit analysis, and the median lethal concentration (LC₅₀) values for eggs and adults were 0.25% and 0.5%, respectively. Treatment with 1% MB showed the highest mortality (100%), with a median lethal time (LT₅₀) estimated of 8.1 h. The efficacy of MB against adults of T. urticae on tomato plants under greenhouse conditions was 97.5% within 96 h post‐treatment. Further, MB showed significant repellent activity against adult females of T. urticae, although this declined with time. Spraying with 1% MB (three times per plant) was not phytotoxic to bean, cucumber, pepper, or tomato plants. CONCLUSION: MB is highly acaricidal and repellent, but not phytotoxic, and is a promising green pesticide.

Invasive alien plants have a significant impact on biodiversity, crop and pasture production, human and animal health, water resources, and economic development. As most low- and middle-income countries do not have the resources to actively manage invasive plants, many have intentionally introduced biological control agents to help manage their most important weeds. Some of these introductions have resulted in the successful control of numerous weeds such as Chromolaena odorata, Mimosa diplotricha, Pistia stratiotes, and Salvinia molesta. These successes are partly due to the reliance on biological control agents that have been tested and utilized elsewhere. However, despite the successes in weed biological control to date, many low- and middle-income countries are reluctant to pursue weed biological control, due to poor perceptions of biological control and lack of capacity. This results in missed opportunities to manage many weeds cost-effectively, and in so doing, increasing production costs and a dependency on herbicides.

In the present study, three aquatic macrophytes, Eichhornia crassipes, Salvinia molesta, and Pistia stratiotes were used to assess their relative efficacies in decontamination of a fish cul...

The search for low cost adsorbents that have metal-binding capacities has intensified in the last decades. Some natural aquatic macrophytes have been studied as adsorbents to remove heavy metals. Macrophytes ease to propagate converts them into plague for many ecosystems while they are also considered by some activities as a residue; therefore its resignification implies positive environmental effects. Whereas these macrophytes can be obtained from water bodies where they develop naturally, controlled production in greenhouses may be more appropriate for its use as filling in fixed-bed reactors that must operate continuously throughout the year. This work focused on obtaining the macrophytes growth parameters in order to calculate the most proper greenhouse containers dimensions and their required cultivation periods to be employed in a determined fixed-bed reactor with a certain effluent flow to filter. These parameters include: the biomass yield, the area required to obtain certain dry weight of a given biosorbent, and the relative growth and propagation rates. Selected macrophytes species were Azolla pinnata, Salvinia molesta, Limnobium leavigatum, Lemna minor and Pistia stratiotes. The characterization of each biomass and the study of their performance as biosorbents were conducted for the removal of Cu (II), Pb (II) and Cr (VI) ions from aqueous solutions, always procuring the WHO guidelines for drinking water. Azolla pinnata resulted in the species with the highest percentage of dry weight (6.56%), and the lowest values of relative growth and propagation rates. This species was as well the most efficient in removal of Cu and Pb (96.7% and 99.4%, respectively), while Pistia stratiotes was better adsorbent for Cr with a removal of 58.8%. The possibility of metal recovery and macrophyte biomasses reuse was also proven. Given their natural abundance, elemental growth conditions and propagation rates, macrophytes represent a low cost alternative to the most efficient commercial adsorbents.

There has been a rapid increase in atmospheric CO2 concentration, from pre-industrial values of 280 ppm to more than 400 ppm currently, and this is expected to double by the end of the 21st century. Studies have shown that plants grown at elevated CO2 concentrations have increased growth rates and invest more in carbon-based defences. This has important implications for the management of invasive alien plants, especially using biological control which is mostly dependent on herbivorous insects. The aim of this study was to investigate the effects of elevated atmospheric CO2 on the biological control of four invasive aquatic weeds (Azolla filiculoides, Salvinia molesta, Pistia stratiotes and Myriophyllum aquaticum). These species are currently under successful control by their respective biological control agents (Stenopelmus rufinasus, Cyrtobagous salviniae, Neohydronomus affinis, and Lysathia sp.) in South Africa. The plant species were grown in a two factorial design experiment, where atmospheric CO2 concentrations were set at ambient (400 ppm) or elevated (800 ppm), and plants were either subjected to or not subjected to herbivory by their target biological control agents. There was an overall increase in biomass production and C:N across all species at elevated CO2, both in the absence and presence of biological control, although C:N of M. aquaticum and biomass of A. filiculoides with herbivory were not constant with this trend. Insect feeding damage was reduced by elevated CO2, except for S. molesta. Thus, we can expect that plants will respond differently to CO2 increase, but the general trend suggests that these species will become more challenging to manage through biological control in future.

Salvinia molesta (native of south-eastern Brazil) is a free floating aquatic fern that has spread to several countries around the globe including Uganda. Under optimum growing conditions, the plant is capable of spreading rapidly where it can have immense environmental, economic and human health impacts. Thick mats of the weed have been recorded in some parts of Lake Kyoga, Uganda where it hinders the abstraction of water, docking and boat take-off, bathing and swimming activities. Therefore this study aimed to determine the extent of S. molesta at selected landing sites in Lake Kyoga and the influence of anthropogenic activities on the weed coverage as well as the effect of physico-chemical parameters of the water on the development of the weed. Quadrats were used to ascertain the coverage of S. molesta while the physico-chemical parameters were determined by standard methods. The results showed significant positive correlation of S. molesta weed coverage with phosphates (PO4-P) and negative correlations with pH, dissolved oxygen (DO) and water flow rate. Though statistically insignificant waste sites recorded the highest overall S. molesta coverage (82.61 ± 21.12 m2) per 400 m2 quadrat followed by boat docks (82.24 ± 19.45 m2), gardens (50.93 ± 11.82 m2) and finally fishing areas (27.94 ± 5.93 m2) respectively. The overall weed coverage was highest around the shoreline locations of Acholi inn landing site (101.72 ± 22.89 m2 per 400 m2) followed by Masindi port (60.39 ± 15.64 m2), Waitumba (41.89 ± 10.55 m2) and the least in the offshore location at Kayei landing site (39.71 ± 10.17 m2). Salvinia molesta distribution in Lake Kyoga is linked to nutrient (PO4-P) supply, proximity to the shoreline and the associated anthropogenic activities. Hence waste sites, gardens and boat docks enhance S. molesta invasion in Lake Kyoga. Therefore, sources of nutrients (phosphates) into Lake Kyoga that favour the proliferation of S. molesta should be minimized through adequate waste treatment and prohibition of cultivation close to the lake. Salvinia molesta coverage along the routes of moving boats should also be contained so as to reduce the spread of the weed in the lake through boat movements. Furthermore, eradication efforts of S. molesta weed in Lake Kyoga should be heightened at the shoreline areas of the lake in the various landing sites within the lake basin.

Little is known of and no flight activity has been documented for the salvinia weevil, Cyrtobagous salviniae Calder and Sands, in the United States. A bucket-type blacklight was used to determine the flight activity of the salvinia weevil in Louisiana from 2013–2015. One trap was operated during summer and early fall 2013 at the LSU AgCenter weevil rearing facility at Houma, LA. Number of weevils captured in the trap ranged from 30 (18 July) to zero (11 September). Weevils per kilogram of salvinia from the adjacent pond ranged from 9.1 (15 August) to 41.5 (8 October). Another trap was run on Cross Lake at Shreveport, LA, during 2013–2015 in conjunction with weevil releases for biological control of giant salvinia, Salvinia molesta Mitchell. During 2013, nine and six weevils were captured in the light trap on 11 and 18 September, respectively. No weevils were captured in the light trap in 2014 because of the late release of weevils in August. During 2015, weevils captured in the trap ranged from ...

It has been reported that the sophisticated structure of the Salvinia molesta surface offered a novel mechanism for long-term air-retention. It was difficult to mimic the structure, for it was composed of complex elastic eggbeater-shaped hairs with a coating of nanoscopic hydrophobic wax crystals, except for the top of the hairs. In this work, a structure of fibres cross on a patterned paper to mimic the ability of S. Molesta is manufactured. The complex elastic eggbeater-shaped hairs with a coating of SU-8 photoresist can support a droplet water of 1 ml. This work offered a new simple method to mimic the properties of S. molesta surface.

In evidently the first study of its kind, vermicompost derived solely from salvinia (Salvinia molesta Mitchell), arguably the world’s most invasive and dominant aquatic weed, has been assessed for its nature and composition. Salvinia is known to contain exceptionally high concentrations of polyphenols, and has unusually ligneous leaves—the two attributes that make it strongly allelopathic and hardy, enabling it to elbow out other vegetation. The present study, supported by UV–vis and FTIR spectrometry, thermogravimetric and differential thermal analysis, and GS-MS analysis, reveals that upon vermicomposting salvinia loses its allelopathy. It happens because chemicals responsible for the alleopathy of salvinia are destroyed, transforming the weed into a potent organic fertilizer. Much of the salvinia’s lignin is also biodegraded. Scanning electron microscopy shows marked disaggregation of the material in the vermicompost as compared to well-formed matrix of salvinia leaves. The findings open up the possibility of utilizing billions of tonnes of salvinia biomass – which not only goes to waste at present but is also a cause of serious harm to the environment – in making organic fertilizer.

The higher areal productivity and lipid content of microalgae and aquatic weed makes them the best alternative feedstocks for biodiesel production. Hence, an efficient and economic method of extracting lipid or oil from aquatic weed, Salvinia molesta is an important step towards biodiesel production. Since Salvinia molesta is an unexplored feedstock, its total lipid content was first measured as 16 % using Bligh and Dyer's method which was quite sufficient for further investigation. For extracting more amount of lipid from Salvinia molesta, methanol: chloroform in the ratio 2:1 v/v was identified as the most suitable solvent system using Soxhlet apparatus. Based on the literature and the preliminary experimentations, parameters such as solvent to biomass ratio, temperature, and time were identified as significant for lipid extraction. These parameters were then optimized using response surface methodology with central composite design, where experiments were performed using twenty combinations of these extraction parameters with Minitab-17 software. A lipid yield of 92.4 % from Salvinia molesta was obtained with Soxhlet apparatus using methanol and chloroform (2:1 v/v) as solvent system, at the optimized conditions of temperature (85 °C), solvent to biomass ratio (20:1), and time (137 min), whereas a predicted lipid yield of 93.5 % with regression model. Fatty acid methyl ester (FAME) analysis of S. molesta lipid using gas chromatograph mass spectroscopy (GCMS) with flame ionization detector showed that fatty acids such as C16:0, C16:1, C18:1, and C18:2 contributed more than 9 % weight of total fatty acids. FAME consisted of 56.32, 28.08, and 15.59 % weight of monounsaturated, saturated, and polyunsaturated fatty acids, respectively. Higher cetane number and superior oxidation stability of S. molesta FAME could be attributed to its higher monounsaturated content and lower polyunsaturated content as compared to biodiesels produced from C. vulgaris, Sunflower, and Jatropha.

The lack of clean water sources, due to the presence of pollutants in water, is a major issue in many countries, including Malaysia. To overcome this problem, various methods have been introduced, including phytoremediation treatment. Therefore, this phytoremediation study examined the ability of five aquatic plants&mdash, Centella asiatica, Ipomoea aquatica, Salvinia molesta, Eichhornia crassipes, and Pistia stratiotes&mdash, to remove three pollutants&mdash, total suspended solids (TSS), ammoniacal nitrogen (NH3-N), and phosphate&mdash, from aquaculture wastewater. Using wastewater samples, each containing 50 g of one of the plants, the pollutant levels were measured every two days for 14 days. The results showed a drastic decline in the concentration of pollutants, where C. asiatica was able to remove 98% of NH3-N, 90% of TSS, and 64% of phosphate, while I. aquatica showed the potential to eliminate up to 73% of TSS and NH3-N, and 50% of phosphate. E. crassipes drastically removed 98% of phosphate, 96% of TSS, and 74% of NH3-N, while P. stratiotes was able to eliminate 98% of TSS, 78% of NH3-N, and 89% of phosphate. S. molesta was efficient in removing 89.3% of TSS and 88.6% of phosphate, but only removed 63.9% of NH3-N.

Biological sampling for biomass estimation is a highly labor intensive process that can benefit from automation using computer vision. In this paper two algorithms the Green Layer Extraction (GLE) method and Morphology and Marker Controlled Watershed Transformation (MMCWT) method are proposed for the estimation of frond (leaf) area of an invasive aquatic fern Salvinia molesta. The two algorithms are tested using a computer controlled automatic testbed. The mean accuracy for the GLE was found to be 89.66% for estimating the number of fronds and 86.74 % for estimating the frond area. For the MMCWT the respective results are 91.92% and 80.68%. Then the results are subsequently used for developing a mathematical model as growth rate estimation of Salvinia molesta for various concentrations of Sodium di-hydrogen phosphate.

Because of water shortage, water treatment and reuse have become crucial. In this study, on the campus of Kun Shan University, an ecological channel with a treatment capacity of 150 CMD and a hydraulic retention time of 46.6 hr was used for the purification of reclaimed water. Different aquatic plants were grown to purify the used water, including floating aquatic plants such as water lettuce (Pistia stratiotes L.), Salvinia (Salvinia molesta D.S. Mitch.), and water hyacinth (Eichhornia crassipes (Mart.) Solms); submerged aquatic plants such as hornwort (Ceratophyllum demersum L.); and emergent plants such as Hygrophila pogonocalyx Hayata and H. salicifolia (Vahl) Nees. In water quality monitoring programs, dissolved oxygen, chemical oxygen demand, suspended solids, total nitrogen, total phosphate, and turbidity were measured weekly. The system was in operation from March 2015 to April 2017, across a total of nine seasons. The results obtained in this study indicated significant improvement in water quality, and dissolved oxygen in water increased from 1.6 mg/L to 5.3 mg/L. After treatment, performance for chemical oxygen demand, suspended solid, turbidity, total nitrogen, and total phosphate removal was 44.0%, 81.2%, 80.1%, 41.6%, and 18.0%, respectively. The results also revealed that Salvinia made little contribution to nitrogen removal, whereas Da-Ann hygrophila, willowleaf hygrophila, and hornwort exhibited great potential for nitrogen removal. Additionally, hornwort demonstrated great potential for phosphorus removal. The purified water is currently used for environmental maintenance and for supplying the landscape pool; moreover, the water purification process reduces the consumption of tap water and improves the efficiency of water utilization.

Phytoremediation is an emerging low cost green technology, which uses plants for treating contaminant in the environment. Phytoremediation potential of locally available aquatic plants Eichhornia crassipes (water hyacinth), Pistia stratiotes (water lettuce) and Salvinia molesta (water fern) in the treatment process of textile wastewater was investi-gated. The reduction efficiencies of chemical oxygen demand (COD), total solids (TS), total suspended solids (TSS), total dissolved solids (TDS), nitrates, phosphates, heavy metals (Cd, Ni and Zn) and total and fecal coliform from the waste-water by each plant species were estimated. Bioconcentration factors (BCF) and translocation factors (TF) of three plant species for Cd, Ni and Zn were also estimated in order to identify their heavy metal absorption and translocation capacity. The results of the study indicated that greater reduction of COD, nitrates, phosphates, total coliform and Zn from the ini-tial wastewater by the three plant species. The results of the study also suggested that the selected aquatic plants are hy-peraccumulators of Cd, Ni and Zn metals. The findings of this study suggest that E. crassipes, P. stratiotes and S. molesta are potential aquatic plants for treating textile waste water.

Giant salvinia (Salvinia molesta) is one of the most noxious invasive species in the world. The fern is known to have primary, secondary, and tertiary growth forms, which are also commonly hypothesized as growth stages. The identification of these forms is primarily based on the size and folding status of the floating leaves. However, we identified 12 forms in the greenhouse and the field. Our experiments showed that the folding of floating leaves is a reversible trait dependent on water access. The floating leaves quickly fold in response to water shortage, reducing water loss and needs, decreasing growth, and avoiding trichome damage. The leaves re-open to allow trichomes repel water and enhance growth when having adequate water supply. Larger secondary or tertiary forms do not produce small-leaf primary forms without high intensity stress. These results do not support the hypothesis that three growth forms represent sequential growth stages. The abnormal small-leaf forms are the result of endocide-induced autotoxicity and some of them never grow into other forms. The development of abnormal forms and reversible leaf folding strategy in response to high stress along with rapid asexual reproduction are major adaptive traits contributing to the invasiveness of S. molesta.

Several ecological services and functions are attributed to macrophytes, which may represent valuable resource for the ecological intensification of tropical fish farming. However, considering the multiple potential eco-services provided by macrophytes, the choice of the most appropriate species requires multiple criteria to assess these eco-services. Five floating macrophytes (Eichhornia crassipes, Lemna minor, Azolla filiculoides, Salvinia molesta and Salvinia spp.) were selected for this study. The six eco-services parameters compared among these macrophytes were: productivity (in % of seeded macrophytes), risk of non-productive cycles, nutritional value, impact on water quality, palatability (expressed as the percentage of plant ingested in 4 h) and ease of use. Experiments to determine these indicators were carried out in simple devices (net cages and plastic tanks) partially immerged in earthen ponds. The palatability of fresh macrophytes (whole or chopped) was studied in ponds using Osphronemus goramy juveniles. All indicators were scored from 1 to 5, and the highest score was assigned to the highest performer. These scores corresponded either to the evaluation of a single parameter (e.g. productivity) or to the average from scores of several parameters (e.g. nutritional score). Multiplier coefficients were applied for nutritional value and palatability. Azolla filiculoides showed the best scores for productivity; L. minor for nutritional value and palatability, and E. crassipes for the lowest risk of non-productive cycles and a positive impact on water quality. After integrating the scores in a multi-parameter matrix, A. filiculoides had the best overall score. The results of this approach to select macrophytes are discussed in light of the eco-services provided by macrophytes which may, in turn, promote the ecological intensification of tropical small-scale aquaculture.

The aquatic fern salvinia can retain an air layer on its hairy leaf surface when submerged under water, which is an inspiration for biomimetic applications like drag reduction. In this research, an electrostatic flocking technique is used to produce a hairy surface to mimic the air-trapping performance of the salvinia leaf. Viscose and nylon flocks with different sizes were selected. A volumetric method was established to analyze the air-retaining performance of the flocking samples, Salvinia molesta and lotus leaves as well. Through air volume change analyses, it is found that another factor that can affect the Salvinia molesta air-retaining ability is the curving of the leaf under water. A flocking sample fabricated by a kind of nylon flock is demonstrated to have a comparable air-retaining ability under static conditions as a Salvinia molesta leaf in its flat form.

Macrophytes have been used to mitigate eutrophication and upgrade effluent quality via their nutrient removal capability. However, the available data are influenced by factors such as microbial activities, weather, and wastewater quality, making comparison between nutrient removal performance of different macrophytes almost impossible. In this study, phytoremediation by Spirodela polyrhiza, Salvinia molesta and Lemna sp. were carried out axenically in synthetic wastewater under controlled condition to precisely evaluate nutrient removal efficiency of NO