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Anthropogenic nutrient enrichment is one of the key global change pressures threatening the health of estuaries. This is evident at the persistently eutrophic Swartkops Estuary located along the warm temperate coast of South Africa. Augmented nutrient-rich baseflows (e.g., stormwater runoff, wastewater treatment work discharges) have resulted in the persistent growth of invasive alien aquatic plants (IAAPs), particularly water hyacinth (Pontederia crassipes), in the upper estuarine reaches. As such, the objective of this study was to investigate the temporal population dynamics of water hyacinth in the Swartkops Estuary to inform management options. Methods included five-weekly sampling campaigns in winter, spring, and summer, interspersed with monthly sampling over a year-long period. Physico-chemical variables and river inflow were measured in situ, while samples were collected for inorganic nutrients, phytoplankton biomass, and IAAP measurements (cover, biomass, and tissue nutrients). Model results indicated that increased water temperature and inorganic nitrogen (ammonium and NOx) levels promoted increased coverage of water hyacinth, while seasonal analysis highlighted reduced (p < 0.05) dissolved oxygen levels during the peak summer IAAP accumulation period. Notably, model results indicated declining IAAP tissue TN and TP concentrations with increasing water temperature, yet overall TN and TP storage was highest in summer due to the extensive water hyacinth cover observed during this period. Overall, the proportionally low and transient nature of nutrient storage by water hyacinth populations, together with the detrimental consequences they facilitate, highlights the need to integrate short-term control measures with catchment-scale management interventions geared towards mitigating the causative drivers. [ABSTRACT FROM AUTHOR]

Water hyacinth (Pontederia crassipes Mart.) is a monocotyledonous aquatic plant renowned for its rapid growth, extensive proliferation, biological invasiveness, and ecological resilience to variations in pH, nutrients, and temperature. The International Union for Conservation of Nature (IUCN) has listed P. crassipes among the top 100 invasive species. However, comprehensive genomic information, particularly concerning its mitochondrial genome (mitogenome), remains surprisingly limited. In this study, the complete mitogenome of P. crassipes was analyzed using bioinformatics approaches. The mitogenome is 399,263 bp long and contains 38 protein-coding genes (PCGs), 24 tRNA genes, and 3 rRNA genes. Sequence analysis revealed that the complete mitogenome of the species contains 3,289 dispersed repeats, and 765 RNA editing sites in protein-coding genes. The P. crassipes mitogenome possessed un-conserved structures, including extensive sequence transfer between its chloroplasts and mitochondria. Our study on the mitogenome of P. crassipes offers critical insights into its evolutionary patterns and phylogenetic relationships with related taxa. This research enhances our understanding of this invasive species, known for its significant biomass and rapid overgrowth in aquatic environments. [ABSTRACT FROM AUTHOR]

The fabrication of nanoparticles by green routes is gaining extensive attention owing to their reliability, sustainability, being eco-friendly, cost-effectiveness, high productivity, and purity and biocompatibility. In the current study, zinc oxide nanoparticles (ZnO NPs) were successfully fabricated via green route using leaf extract of Pontederia crassipes. The synthesized sample was characterized by various techniques, such as FT-IR, XRD, BET, FEEM, TEM, and EDS. The characterization results confirmed the success of the synthesis process, with prepared ZnO NPs exhibiting good purity. The synthesized ZnO NPs were employed as an adsorbent for the removal of carcinogenic anionic congo red (CR) and cationic malachite green (MG) dyes from aqueous solutions. All experiments were performed in a batch process where the effects of dye concentration, adsorbent dose, equilibrium time, temperature, pH, and salinity have been investigated. High removal capacity of 96.39% for CR was achieved with pH 2, dye concentration of 40 mg/L, and adsorbent dosage of 1.2 g within 30-min equilibration time. On the other hand, the maximum adsorption efficiency for MG dye was 95.75% with pH 7, dye concentration of 15 mg/L, and ZnO dosage of 1.2 g within 60-min equilibration time. The Temkin and Freundlich isotherm models match the dye adsorption process for CR and MG, respectively. Depending on the thermodynamic functions, it was proven that the adsorption process for both dyes is endothermic and spontaneous. Employing ZnO as anti-breast cancer (MCF7 cancer cell line) was also studied. ZnO NPs exhibit high in vitro cytotoxic efficacy against cancerous MCF7 (IC50 = 39.3 μg/mL. [ABSTRACT FROM AUTHOR]

This study is the first report evaluating the microplastic (MP) and macroplastics capture potential of Pontederia crassipes. Total of 3691 (508 microplastic and 3183 macroplastic) particles were extracted from the roots of 12 examined specimens. Mean macroplastic abundance in the roots was found as 265±44 macroplastic/specimen. Majority of the extracted macroplastics were fragment in shape, blue in color. Mean microplastic abundance was found as 42±23 MPs/specimen. Majority of the extracted microplastics were fragment in shape, blue in color and less than 500 µm in size. Results of this preliminary study showed that this species have significant ability to adsorb micro and macroplastics by the roots which makes them perfect employees for integrated floating systems. [ABSTRACT FROM AUTHOR]

Considering the considerable environmental impact resulting from basic chromium sulfate, the exploration of vegetable tanning materials as an eco-friendly alternative has gained substantial interest. This study endeavors to extract tannins from Pontederia crassipes using various solvents (water, acetone, methanol, and ethanol) and evaluate their potential as a vegetable tanning agent for leather processing. Among the solvents, methanol exhibited the highest extraction efficiency at 26.34%. UV–Vis spectroscopy, FT-IR spectroscopy, and titrimetric analysis confirmed the presence of total tannins at 152.25 mg/g, which encompassed polyphenolic compounds such as epicatechin, catechin hydrate, and catechol. The antimicrobial behavior of the extracted tannin was confirmed by antimicrobial analysis. Notably, leather tanned with Pontederia crassipes tannin displayed an impressive shrinkage temperature of 83.31 °C, tensile strength 286.33 kg/cm2, and elongation 63.33%. This innovative tanning approach also yielded enhanced properties such as tensile strength, Bauman tear strength, stitch tear strength, tongue tear strength, and percentage of elongation, surpassing those of traditional vegetable-tanned leather. A closer look at the surface of the tanned leathers using Scanning electron microscopy (SEM) revealed compact fiber structures and uniform surface. Moreover, the Fourier-transform infrared spectroscopy (FTIR) analysis revealed clear functional groups within the Pontederia crassipes tanned leather, as evidenced by the broad peak observed. These results collectively imply that Pontederia crassipes tannin presents promise as an eco-friendly substitute for basic chromium sulfate and a novel reservoir of vegetable tannins for the leather sector.

Host specificity determination of weed biocontrol agents has historically relied on evidence generated through quarantine trials in the region of introduction. These trials could give 'false positive' results due to a maximum type I error probability, and where possible, more research under field conditions should be conducted in the region of origin. The oligophagous, semiaquatic grasshopper, Cornops aquaticum Bruner (Orthoptera: Acrididae, Tetrataeniini), was released in South Africa for the biological control of Pontederia crassipes Pellegrini and Horn (Pontederiaceae). The aim of this study was to assess how the performance and field host range of C. aquaticum varies according to its stages of development, and how this contributes to the understanding of the relationship between the fundamental (laboratory‐based) and the ecological (field‐based) host range of this grasshopper, and its implications for water hyacinth biocontrol. We conducted post‐release laboratory no‐choice trials, confining early instars (instars 1 and 2), later instars (instars 3–6), and adult females and males in mesh cages, to determine insect performance on wetland plants growing in sympatry with P. crassipes. Also, gut analysis from field‐collected C. aquaticum was done to determine the ecological host range of this insect, identifying epidermal tissue of consumed plants. In no‐choice trials, survival rates of the later instars and adult C. aquaticum were similar on Pistia stratiotes L. (Araceae), Oxycaryum cubense (Poepp. & Kunth) Lye (Cyperaceae), and P. crassipes. However, under field conditions, P. crassipes and the congeneric Pontederia azurea Sw. were the only plant contents in the guts of early instars and the most abundant species in later instars and adults. The results support the hypothesis that C. aquaticum is an oligophagous insect on the genus Pontederia, and that different life stages should be considered when conducting host‐specificity trials in externally feeding mobile herbivore species. Diet composition of field‐collected insects thus could help detect false positives in laboratory trials, being an additional and realistic approach in understanding and predicting the selection processes of the insect in the new environment. Retrospective analysis of potential agents that were rejected due to lack of host‐specificity, using the methods from this study, could add a suite of additional agents to programs where invasive weeds remain unmanaged. [ABSTRACT FROM AUTHOR]

Owing to its high concentrations of nitrogen and phosphorus, the slurry from water hyacinth (Pontederia crassipes) biogas production cannot be discharged directly without further treatment. To achieve the target of water recycling, a new strategy of combining a Carrousel oxidation ditch with a water spinach wetland was developed in this study for the harmless treatment of Pontederia crassipes biogas slurry. First, the water quality characteristics of the biogas slurry were measured. Then, comprehensive tests of the combined slurry treatment system were carried out to verify pollutant removal performance and mechanism. The results showed that the Carrousel oxidation ditch reduced the inlet pollutant load of the subsequent water spinach wetland. The chemical oxygen demand (COD), and ammonium nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) contents of the average effluent from the combined system were less than 50 mg/L, 1.6 mg/L, 6 mg/L, and 0.5 mg/L, respectively, which means that all met urban sewage treatment standard of Level 1 Grade A (GB18918-2002). Gas chromatography – mass spectrometry analysis showed that the combined system had decreased various types of organic pollutants in the biogas slurry exponentially, efficiently removing alkane pollutants, aromatic hydrocarbons, and heterocyclic compounds. Scanning electron microscopy images revealed very large surface area of the water spinach roots in the wetland, which played important roles in enriching the microorganisms and trapping organic matter. Plant absorption, microbial degradation, and filtration were the primary ways in which the water spinach wetland purified the biogas slurry.

Common water hyacinth, Pontederia (former Eichhornia) crassipes is a notorious aquatic invasive species. In African Great Lakes, the species is known for deleterious social, economic, and environmental impacts in lakes such as Victoria, Kyoga, Albert, Malawi, Tanganyika, Tana, and Naivasha. We report invasion and establishment of the species in Lake Edward, Kazinga Channel and possibly in Lake George. Lake Edward is one of the African Great Lakes. Common water hyacinth was observed at multiple locations on Lake Edward and Kazinga Channel. Presence of 'mats' of the weed with flowers is a sign of successful establishment. We observed free floating Common water hyacinth plants, indicating that the invasion is spreading. The invasion and establishment of the weed threatens a fishery of significant importance to rural livelihoods, fish species of conservation importance and tourism among others. At the current extent of invasion, mechanical removal and use of water hyacinth weevils, if expedited, could be adequate for stopping the expansion of the invasive weed. We recommend immediate action by government agencies responsible for the management of fisheries and protected areas to control the weed. [ABSTRACT FROM AUTHOR]

Primary producer responses to cumulative regulating factors were investigated in a temporarily closed microtidal estuary. We hypothesised that the phytoplankton chlorophyll-a concentration (Chl a) and invasive alien aquatic plant (IAAP) abundance would be highest during the low-flow season and that shifts in community structure would be driven by salinity and nutrient gradients. The augmented freshwater inflow limited phytoplankton Chl a (<5 µg Chl a l−1) due to low freshwater residency, while isolated instances of increased Chl a (≥10 but ≤20 µg Chl a l−1) were recorded following a brief period of mouth closure. Cyanophyceae proliferated for 67% of the study period with maximum abundance (>10 000 cells ml−1) recorded in spring owing to increased water retention. A community consisting of co-dominant Cryptophyceae, Euglenophyceae and IAAPs was recorded during winter, indicating a shared preference for slow-flowing, low-salinity (<5) eutrophic habitats. Dinophyceae was the only phytoplankton class that showed niche differentiation by favouring the mesohaline lower reaches. The homogenisation of dynamic estuarine gradients and the prevalence of nutrient-tolerant primary producers is indicative of the degraded state of this estuary as a result of consistent nutrient-enriched freshwater baseflows. The application of a multidisciplinary restoration approach is required to improve the ecosystem health. [ABSTRACT FROM AUTHOR]

Invasive floating aquatic vegetation negatively impacts wetland ecosystems and mapping this vegetation through space and time can aid in designing and assessing effective control strategies. Current remote sensing methods for mapping floating aquatic vegetation at the genus level relies on airborne imaging spectroscopy, resulting in temporal gaps because routine hyperspectral satellite coverage is not yet available. Here we achieved genus level and species level discrimination between two invasive aquatic vegetation species using Sentinel 2 multispectral satellite data and machine-learning classifiers in summer and fall. The species of concern were water hyacinth (Eichornia crassipes) and water primrose (Ludwigia spp.). Our classifiers also identified submerged and emergent aquatic vegetation at the community level. Random forest models using Sentinel-2 data achieved an average overall accuracy of 90%, and class accuracies of 79–91% and 85–95% for water hyacinth and water primrose, respectively. To our knowledge, this is the first study that has mapped water primrose to the genus level using satellite remote sensing. Sentinel-2 derived maps compared well to those derived from airborne imaging spectroscopy and we also identified misclassifications that can be attributed to the coarser Sentinel-2 spectral and spatial resolutions. Our results demonstrate that the intra-annual temporal gaps between airborne imaging spectroscopy observations can be supplemented with Sentinel-2 satellite data and thus, rapidly growing/expanding vegetation can be tracked in real time. Such improvements have potential management benefits by improving the understanding of the phenology, spread, competitive advantages, and vulnerabilities of these aquatic plants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aerial parts and roots of water hyacinth (Pontederia crassipes) were investigated. • Two new phenylnaphthalic anhydrides were isolated from the roots of water hyacinth. • The structures of compounds were determined by 1D and 2D NMR and HRESIMS spectra. • 8-Phenylphenalenones showed antiprotozoal activity against Trypanosoma cruzi. Nineteen compounds were isolated from the aerial parts and roots of Pontederia crassipes Mart. [≡ Eichhornia crassipes (Mart.) Solms] (Pontederiaceae), including the new 4-hydroxy-5-phenyl-1,8-naphthalic anhydride (1) and 4-hydroxy-5-(4-hydroxyphenyl)-1,8-naphthalic anhydride (2). In addition, chemically related phenylnaphthalic acid derivatives 1a and 2a were obtained. The structures of the compounds were established by 1D and 2D NMR and ESI-HRMS analysis. 8-Phenylphenalenones 3 and 4 were evaluated for antiprotozoal activity against trypomastigote forms of Trypanosoma cruzi and displayed moderate activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • A sustainable route for synthesizing Zno, biochar, and ZnO /biochar nanomaterials is Conducted. • Characterization study of synthesized materials it, demonstrated. • Eco-friendly synthesized materials for degrading of RhB dye. Were obtained as photocatalysts. • ZnO biochar efficiency of Single has a maximum photocatalytic/degradation of 92%. In the current study, biochar, as a porous and low-cost carbon derived from Pontederia crassipes L. leaves, was loaded with zinc oxide for the photocatalytic discoloration of Rhodamine B dye in aqueous suspension under solar light irradiation. For the comparison, the unmodified zinc oxide and biochar samples were prepared. The synthesizing materials were investigated by X-ray powder diffraction, UV-DRS spectrophotometer, field emission scanning electron microscopy, Fourier transform infrared spectrometer, and Raman spectroscopy. The synthesized ZnO/Biochar hybrid has improved features, besides narrowing the band gap energy, and enhancing the surface area of the photocatalyst. The ZnO/biochar nanohybrid displayed an excellent photocatalytic degradation efficiency (99. 67 %) of Rhodamine B in the presence of H 2 O 2 with 120 min of solar light irradiation. The results of recyclability study of ZnO/Biochar in the photocatalysis process verified its physical and chemical stability after five repeated cycles, hence it retained of 82.24 % of initial activity. Furthermore, the photocatalytic discoloration reaction was compatible with the pseudo-first-order kinetic model [ABSTRACT FROM AUTHOR]

Invasive floating aquatic vegetation negatively impacts wetland ecosystems and mapping this vegetation through space and time can aid in designing and assessing effective control strategies. Current remote sensing methods for mapping floating aquatic vegetation at the genus level relies on airborne imaging spectroscopy, resulting in temporal gaps because routine hyperspectral satellite coverage is not yet available. Here we achieved genus level and species level discrimination between two invasive aquatic vegetation species using Sentinel 2 multispectral satellite data and machine-learning classifiers in summer and fall. The species of concern were water hyacinth (Eichornia crassipes) and water primrose (Ludwigia spp.). Our classifiers also identified submerged and emergent aquatic vegetation at the community level. Random forest models using Sentinel-2 data achieved an average overall accuracy of 90%, and class accuracies of 79–91% and 85–95% for water hyacinth and water primrose, respectively. To our knowledge, this is the first study that has mapped water primrose to the genus level using satellite remote sensing. Sentinel-2 derived maps compared well to those derived from airborne imaging spectroscopy and we also identified misclassifications that can be attributed to the coarser Sentinel-2 spectral and spatial resolutions. Our results demonstrate that the intra-annual temporal gaps between airborne imaging spectroscopy observations can be supplemented with Sentinel-2 satellite data and thus, rapidly growing/expanding vegetation can be tracked in real time. Such improvements have potential management benefits by improving the understanding of the phenology, spread, competitive advantages, and vulnerabilities of these aquatic plants.

Water hyacinth ( Pontederia crassipes Mart.) is a monocotyledonous aquatic plant renowned for its rapid growth, extensive proliferation, biological invasiveness, and ecological resilience to variations in pH, nutrients, and temperature. The International Union for Conservation of Nature (IUCN) has listed P. crassipes among the top 100 invasive species. However, comprehensive genomic information, particularly concerning its mitochondrial genome (mitogenome), remains surprisingly limited. In this study, the complete mitogenome of P. crassipes was analyzed using bioinformatics approaches. The mitogenome is 399,263 bp long and contains 38 protein-coding genes (PCGs), 24 tRNA genes, and 3 rRNA genes. Sequence analysis revealed that the complete mitogenome of the species contains 3,289 dispersed repeats, and 765 RNA editing sites in protein-coding genes. The P. crassipes mitogenome possessed un-conserved structures, including extensive sequence transfer between its chloroplasts and mitochondria. Our study on the mitogenome of P. crassipes offers critical insights into its evolutionary patterns and phylogenetic relationships with related taxa. This research enhances our understanding of this invasive species, known for its significant biomass and rapid overgrowth in aquatic environments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hao, Jiang, Pan, Guo, Chen, Li, Liu, Guo, Luo and Jia.)

Water hyacinth, Pontederia crassipes (Martius) [≡Eichhornia crassipes (Martius) Solms-Laubach] (Pontederiaceae), is native to South America, but has expanded its range to many other regions of the world including South Africa. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released as a biological control agent and has established in several regions. Recently, the indigenous species Echthrodelphax migratorius Benoit, (Hymenoptera: Dryinidae) was discovered in South Africa parasitising M. scutellaris. This newly discovered relationship might have repercussions for the efficacy of biological control of water hyacinth by the delphacid. The wasp may negatively impact M. scutellaris populations making it difficult for the agent to successfully manage the invasive weed. Contrarily, the parasitoid may be beneficial by keeping the M. scutellaris populations stable, serving as a natural enemy. [ABSTRACT FROM AUTHOR]

[Display omitted] • AC/ZnO nanocomposites are synthesized by an eco-friendly green route. • Adsorptive removal of Congo Red and Malachite Green dyes was quantified exhibiting promise adsorptive behavior of AC/ZnO surface. • Synthesized AC/ZnO nanocomposite shows removal efficiency of 98.87 % for Congo Red and 99.23 % for Malachite Green. In the current study, a facile and green route for synthesis zinc oxide supported activated carbon nanocomposites (AC/ZnO) using Pontederia crassipes leaves has been conducted. The synthesized ZnO/AC nanocomposites have been obtained as adsorbents to remove Malachite Green (MG) and Congo Red (CR) dyes after characterization via XRD, FTIR, FE-SEM, EDX, BET-BJH, TEM and Raman spectroscopy techniques. The influence of five parameters such as time, adsorbent dosage, solution pH, dye concentration and temperature has been optimized as batch experiments. The results showed that the ZnO/AC (10 %) nanocomposite showed the better removal efficiency of 98.87 % for CR and 99.23 % for MG with an estimated maximum adsorption capacity of 987.77 mg/g for CR and 74.36 mg/g for MG. The Freundlich, Halsey isotherms (R2 = 0.9969 for CR and 0.9842 for MG) and pseudo-second-order (R2 = 0.9996 for CR and = 0.9997 for MG) models were most appropriate in the description of the adsorption process. These findings confirmed that ZnO/AC fabricated via green approach is an efficient adsorbent for the removal of cationic and anionic dyes and could possibly be used for the treatment of other industrial textile effluents. [ABSTRACT FROM AUTHOR]

• M. scutellaris has established, dispersed, and is impacting control of P. crassipes. • Wild populations of M. scutellaris are producing macropters and dispersing via flight. • Dispersal has been documented from herbicide treated sites and across terrestrial habitat. • New populations have reached an equilibrium density that does not change with more releases. Changes to the historical flow and nutrient levels of freshwater bodies in Florida have made control of waterhyacinth difficult. Biological control agents were introduced to augment herbicidal control of this plant. The newest insect agent, Megamelus scutellaris , was released in 2010, has established, and has been documented dispersing more than 6 kms away from release locations, across aquatic and terrestrial habitats. These insects were able to successfully disperse away from herbicide treated areas and across terrestrial habitats to reach new mats of waterhyacinth. Macropterous individuals were the first M. scutellaris documented at three non-release sites, indicating that the established wild populations are producing flighted individuals and are dispersing actively. Established populations appear to have reached an equilibrium density of 10.74 ± 19.74 M. scutellaris /m2 and this does not fluctuate with additional releases. [ABSTRACT FROM AUTHOR]

• Megamelus scutellaris is parasitized by a mymarid wasp that primarily utilizes a native delphacid. • Parasitism rate of M. scutellaris decreases farther away from the parasitoid's primary host. • Parasitism was not density dependent suggesting it will not interfere with biological control. The biological control agent Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released in Florida in 2010 to improve control of the invasive aquatic plant, Pontederia (Eichhornia) crassipes (Mart.) Solms (Commelinales: Pontederiaceae). A native egg parasitoid, Kalopolynema ema (Schauff and Grissell) (Hymenoptera: Mymaridae), was documented utilizing M. scutellaris , potentially limiting its effectiveness as a biological control agent. An experiment to determine if the distance from K. ema 's native host impacted parasitism rate of M. scutellaris was conducted in artificial ponds with naturally occurring populations of the native insect species. Models indicated that parasitism decreased with distance from the native host and with increasing M. scutellaris density. Although parasitism increased with K. ema density, rainfall, and temperature, parasitism was low with over half of the test plants indicating no signs of parasitism on M. scutellaris. The lack of a density dependent response by K. ema suggests it will not interfere with biological control of P. crassipes in Florida. [ABSTRACT FROM AUTHOR]