Water Hyacinth Research Articles

Effect of n‐pentanol with novel water hyacinth biodiesel‐diesel ternary blends on diesel engine performance and emission characteristics

AbstractPresent research deals with crude oil production from water hyacinth biomass and its biodiesel preparation. Alcohol additive n‐pentanol is mixed with biodiesel and diesel blends to identify their effects on diesel engine performance and emission parameters experimentally. Water hyacinth oil (WHO) is produced through Soxhlet extraction technique, and its biodiesel is prepared by transesterification. n‐pentanol is mixed through magnetic stirring in biodiesel‐diesel blends to improve their combustion quality and efficiency. Prepared fuel blends properties are examined as per ASTM standards. Experimental results reveal that, BSFC and BTE are evaluated as 0.26 kg/kW‐h and 29.5%, respectively, with HC emissions as 29 ppm, CO emissions as 0.28 vol%, NOx emissions as 330 ppm and CO2 emissions as 2.21 vol% for WHB20D75P5 fuel at maximum load. The comparison of D100 and WHB20D80 with respect to WHB20D75P5 reveals 3.27% reduction and 7.27% improvement in BTE, respectively. Both HC and CO are reduced by 14.70% and 22.22% for WHB20D75P5 fuel compared to diesel. NOx and CO2 emissions are increased by 6.79% and 12.75% for WHB20D75P5 fuel compared to diesel. Overall, WHB20D75P5 fuel is the best performer.

Anaerobic sludge from a full-scale biodigester: physico-chemical and organic characterization, and principal component analysis (PCA)

The biological transformation of the organic fraction of municipal solid waste into bioenergy yields a solid digested material known as anaerobic sludge, comprising a mixture of organic and inorganic substances. This sludge holds significant potential as a renewable resource for agricultural reuse. However, there is also the potential risk of contamination from this material in receiving environments. Therefore, it is crucial to assess the characteristics of this material to ensure compliance with local regulations regarding its soil application, aiming to avoid adverse environmental impacts and ensure proper and viable disposal. In this study, conducted to explore the characteristics of bottom sludge collected from a pilot-scale anaerobic biodigester, various parameters were analyzed. The biodigester in question had a capacity of 1300 liters and a useful volume of 1000 liters, digesting food waste and water hyacinth (Eichhornia crassipes) in a ratio of 20% in terms of volatile solids from the macrophyte to the volatile solids of the food waste. A multivariate analysis was conducted on the following parameters: metals (Al, Ba, Cd, Cr, Cu, Fe, Mn, Mo, Pb, Se, V, Zn, Na, and K); total, fixed, and volatile solids; alkalinity; volatile fatty acids; ammonia; Kjeldahl nitrogen (NTK); and organic, inorganic, and total carbon (COT), to observe possible correlations among these parameters. Additionally, the sludge underwent nuclear magnetic resonance (NMR) analysis for detection and characterization of organic compounds. This approach provided a deeper understanding of the properties of anaerobic sludge produced strictly under the aforementioned conditions, contributing to further research in the field.

Effectiveness of aquatic plants as phytoremediation in palm oil processing factory wastewater

The research aims to see the effect of using kale (Ipomoea Aquatica), water hyacinth (Eichhornia crassipes) and apu-apu (Pistia statiotes) in the phytoremediation process on water quality in palm oil mill waste. The design used in this research is an experimental design using a non-factorial Completely Randomized Design (CRD). The treatments in the study used 4 treatments and three replications, namely P1: 20 liters of palm oil waste + 600 grams of water spinach, P2: 20 liters of palm oil waste + 600 grams of water hyacinth, P3: 20 liters of palm oil waste + 600 grams of apu-apu, P4: 20 liters of palm oil waste. The observation parameters in this study include pH, DO, Temperature, Nitrate and Phosphate. The results showed that the best aquatic plants in phytoremediation of palm oil wastewater were in treatment B (water hyacinth) and the lowest in treatment D (control). From the results obtained, it can be concluded that water hyacinth is suitable for use as a plant in phytoremediation and is able to improve the quality of palm oil wastewater.

Optimizing the Role of User and Maintainer Groups (Kpp) in the Settlement Quality Improvement Program (Case Study of Klasabi Slum Settlement, Sorong City)

The purpose of this research is to optimize the role of the user and maintainer group (KPP) in the Klasabi slum quality improvement program of Sorong City. In this case, the environmental conditions in this settlement are reviewed, the role of KPP is evaluated, and optimization strategies are also formulated that can be used for the environmental management of Klasabi slums in Sorong City. This research is quantitative with the method used in this research, namely the descriptive method with a case study technique through data collection from the results of distributing questionnaires, interview results, direct observation, and using other official documents analyzed using validity test analysis and reliability tests. Based on the results of the data validity test and the data reliability test, it was found that the research data or questionnaire data used in the study was valid and reliable. research data or questionnaire data used in this study is valid or reliable. The results showed that environmental conditions, seen from several perspectives, including ecological, economic, social, and cultural, can be considered good. However, when viewed in ecological conditions, especially in road and drainage conditions, it is still considered adequate by the community because there is no equal distribution of facility development. Also, the role of the user and maintainer group (KPP) is assessed as not optimal in carrying out its duties and responsibilities; this is supported by the results of the conducted interviews and observations made by researchers. In addition, optimization strategies can be carried out, such as structuring the Klasabi area around Deo Airport in Sorong City, handling slum houses by the government to support the development of water tourism, optimizing the use of water hyacinth plants that can be developed by community members using SIKIM and BLK facilities, and providing capital loans to support the business of making traditional snacks, traditional Papuan handicrafts, and Papuan craftsmen certification training in Sorong City.

Weeds and Their Response to Changing Climate: A Review

Climate change is one of the most important parameters to cause alteration in weed composition, population growth, life processes, physiological development, and infestation pressure. A few of the weed species may become inactive, while the rest may become aggressive invaders. Weeds possess unique biological characteristics and ecological range that enable them to tolerate and successfully intrude in any ecosystem with varied environmental conditions. Rising carbon dioxide, will benefit C3 crops to expand their photosynthetic capacity, thus leading to increased biomass production and productivity, on the other hand increased temperatures will benefit the C4 crops. These differences in response of C3 and C4 crops to changing climate will influence crop-weed interaction, most likely at the expense of crop. Moisture is another important environmental factor which plays a major role in weed seed germination, thus the survival. Temperature and relative humidity influence the course of absorption, translocation, and metabolism of herbicides in plants, any change in their range leads to decreased herbicide efficacy and thus the weed control. Studies focussed on the performance of weeds under elevated environmental factors help to make strategic decisions on their management before having their impact on change in weed biological aspects, and foresee the future with elevated temperature and carbon dioxide conditions. Weeds such as Parthenium hysterophorus, Sphagneticola trilobata, Prosopis juliflora and Eichhornia crassipes, have been identified as potential future threats. Consequently, exploring the bioprospecting potential of these weeds is seen as an inevitable necessity.

Sustainable seedling pots: Development and characterisation of banana waste and natural fibre-reinforced composites for horticultural applications

Plastic pots used in horticultural nurseries generate substantial waste, causing environmental pollution. This study aimed to develop biodegradable composites from banana pseudo-stem reinforced with agricultural residues like pineapple leaves, taro and water hyacinth as eco-friendly substitutes. The aim of this study is to develop optimised banana biocomposite formulations with suitable reinforcements that balance mechanical durability, biodegradation, and seedling growth promotion properties to serve as viable eco-friendly alternatives to plastic seedling pots. This study was carried out by fabricating banana fibre mats through pulping, drying and hot pressing. Composite sheets were reinforced with 50 % pineapple, taro or water hyacinth fibres. The mechanical properties (tensile, yield strength, elongation, bursting strength), hydrophilicity (contact angle, water absorption), biodegradability (soil burial test), and seedling growth promotion were evaluated through appropriate testing methods. The results show that banana-taro composites exhibited suitable tensile strength (25 MPa), elongation (27 %), water uptake (41 %) and 82 % biodegradation in 60 days. It was observed that biodegradable seedling trays fabricated from banana-taro composite showed 95 % tomato seed germination and a 125 cm plant height increase in 30 days, superior to plastic trays. The finding shows that the study demonstrates the potential of banana-taro biocomposites as alternatives to plastic nursery pots, enabling healthy seedling growth while eliminating plastic waste pollution through biodegradation.

Cotton aphid (Aphis gossypii Glover: Aphididae) influence associated to water hyacinth nutrient (Pontederia crassipes Mart.: Pontederiaceae) in lath house conditions in Great Rift Valley of Ethiopia

The cotton aphid, Aphis gossypii Glover is a polyphagous herbivore known worldwide. The aphid infestation could be considered as a challenge to crops, but an opportunity for alien invasive weed management. Hence, this study was initiated to investigate the potential of cotton aphid on the management of water hyacinth. Aphid-infested water hyacinth plants were used as a stock for rearing the aphid in a lath house at Ethiopian Sugar Corporation, Research and Development Center, Wonji. After rearing, randomly collected 30 aphids were placed onto water hyacinth plants cultivated under three nutrient levels. Aphid population, water hyacinth biomass and percent nitrogen and phosphorus were analyzed. The water hyacinth treated with a high nutrient level had the highest (295.0) mean aphids on apical leaves followed by the middle (178.3) and basal (104.7) leaves. The water hyacinth subjected to medium and no aphid treatment had the highest dry (44.3 g) biomass. However, when treated with a low nutrient level and aphids resulted in the lowest dry (31.9 g) biomass. Nitrogen and phosphorus concentrations were found high in the water hyacinth that received a high nutrient and no aphid treatment. The presence of the aphids reduced the biomass and nutrient concentration of the invasive weed. The findings of the current study revealed that the cotton aphid affected the water hyacinth in the lath house conditions in Ethiopia.

Risk assessment of four toxic heavy metals in terrestrial and aquatic ecosystems around BSCIC tannery industrial estate of Savar, Dhaka,Bangladesh.

The shifting of tannery industries from Hazaribagh to Savar adjacent to Dhaleshwari River might have inevitable adverse impacts, especially the heavy metal contamination of both terrestrial and aquatic ecosystems. The study was carried out to investigate the concentrations of four heavy metals in the soil, water, and plant samples collected from around Dhaleshwari River adjacent to the Bangladesh Small & Cottage Industries Corporation Tannery Industrial Estate, Dhaka. This study revealed that average concentrations of cadmium and chromium in soil exceeded the maximum permissible limit of World Health Organization (1996) and average concentrations of lead, cadmium, and chromium in water exceeded the maximum permissible limit of World Health Organization (2011) and Environmental Conservation Rules (1997). The average concentrations of lead, cadmium, and chromium in the roots and shoots of both Eichhornia crassipes and Cynodon dactylon exceeded the maximum permissible limit of Food and Agriculture Organization/ World Health Organization (2016). Ecological risk assessment using indices model for soil pollution indicated that soil is mostly contaminated with cadmium and chromium which can pose strong ecological risk Health risk assessment using indices model for water pollution revealed the high degree of contamination and unacceptable non-carcinogenic risk and carcinogenic risk for adults as well as children through ingestion of water. Average bioconcentration factor and bioaccumulation factor were higher in Eichhornia crassipes than Cynodon dactylon for lead, cadmium, and chromium. Average translocation factor was also higher in Eichhornia crassipes for all the metals except cadmium. It is suggested remedial and mitigation measures be instituted to control environmental degradation of the newly established Tannery Industrial Estate.

Evaluation of the phytoremediation potential of selected hydrophytes grown in wastewater. A case study in Sheikhupura, Pakistan

Water pollution is a major environmental issue and human health risk worldwide. With rapid industrialization and economic growth, water bodies are contaminated at large scale. In the current study the concentration of four heavy metals (HMs) cadmium (Cd), copper (Cu), nickel (Ni), and manganese (Mn) was measured in water, sediment, and hydrophytes (Eichhornia Crassipes, Pistia stratiotes and Lemna minor) samples collected from wastewater stream in Sheikhupura, Punjab, Pakistan. The results revealed that the concentrations of Cd (0.23 mg L-1), Cu (5.00 mg L-1), Mn (6.00 mg L-1), and Ni (3.00 mg L-1) in water samples were above the permissible limits (APL) set by the World Health Organization (WHO). However, the concentration of Cd, Cu, Mn, and Ni in sediment samples was found to be below the maximum permissible limits (BMPL) set by WHO. The WHO permissible limits for Cd, Cu, Mn, and Ni in water is 0.01, 0.02, 0.20, and 1.40 mg L-1 respectively while in sediments is 3.00, 100, 2000, and 50 mg kg-1 respectively. In addition, Mn concentration was highest among all the tested hydrophytes, water, and sediment samples. HMs contents were higher in hydrophytes as compared to water and sediment samples. In addition, all three hydrophytes were found to absorb HMs from wastewater with bioaccumulation factor ranging from 2.52 to 216. Current data revealed that Pistia stratiotes have greater potential to absorb HMs from water as compared to Eichhornia Crassipes, and Lemna minor

Linking hydrological connectivity with the richness and composition of aquatic invertebrates across the Paraná River floodplain, Argentina

Lateral hydrological connectivity can affect the community characteristics by promoting dispersal of organisms between the river and its floodplain. We investigated the species richness, specific diversity, and relative abundance of microcrustaceans transported by the flood and the macroinvertebrates retained by Pontederia crassipes Mart. roots in five floodplain lakes with different connectivity within the RAMSAR Site Humedales Chaco. Due to differences in the slopes of the floodplain studied, the connectivity was determined by the topographic location of each lake, rather than by the distance from the river. During the hydrological connection, there was a transverse gradient in the physical and chemical characteristics of the water, with an increase in the electrical conductivity and a decrease in dissolved oxygen and suspended solids in the more isolated sites. A total of 62 species of microcrustaceans (48 cladocerans and 14 copepods) and 63 taxa of macroinvertebrates were identified. The microcrustaceans had high species richness in the three most connected lakes, whereas the macroinvertebrates had a peak in taxa richness in the lakes with intermediate connectivity. The low beta diversity (βw) for both microcrustaceans (14.63 %) and macroinvertebrates (16.9 %) indicated that taxa richness varied little between sites with different hydrological connectivity. In both assemblages, cluster analysis based on the similarity of the relative abundance grouped the three sites more connected and separated from the less connected sites. Our results suggest that species richness followed different patterns in different assemblages across the lateral gradient and that the hydrological connectivity was more related to the relative abundance of microcrustaceans and macroinvertebrates than to the classical measures of βw. Species diversity indices did not vary between sites. The high total species richness of invertebrates is mainly a result of the spatial arrangement of the different floodplain lakes.

Production efficiency of young Acehnese cattle by giving fermented of water hyacinth (Eichhornia crassipes), palm fronds, and sago stems with addition of digestive enzymes

Production efficiency of young Acehnese cattle by giving fermented of water hyacinth (Eichhornia crassipes), palm fronds, and sago stems with addition of digestive enzymes

Efficient ORR catalyst: porous activated carbon prepared from water hyacinth with high N content

Efficient ORR catalyst: porous activated carbon prepared from water hyacinth with high N content

Phytoremediation Potential of Macrophytes from Calcium Fortified Ground Water under Laboratory Condition to Improve Water Quality

To select the best macrophyte for the phytoremediation of calcium from Ca-fortified ground water and inland saline water, 1 week screening was done for Eichhornia crassipes, Salvinia molesta and Lemna minor by using four effective concentrations of Calcium viz., 200, 400, 600 and 800 mg L–1. Experiment was done in triplicate. Water samples were collected at one day interval and plant samples at the end of experiment. The Calcium uptake concentration was found significantly (p<0.05) higher for E. crassipes on 6th day (5.37%) of experiment at effective concentration 800 mg L–¹, followed by S. molesta (4.87%) and L. minor (4.13%). Further experiment was conducted for 1 month for water quality analysis and testing the Calcium uptake, and found that there was significant improvement in water quality parameters. The finding of this study will serve baseline information for treatment of inland saline water to make it useful for various agricultural and aquaculture applications.

How does the diurnal biological clock influence electrokinetics in a living plant?

The existence of electrical potential in plant tissues has been studied for decades to understand its contribution toward the plants' health and developmental aspects. This potential is profoundly controlled and modulated by the electrokinetics involved in the flow navigated through the narrow conduits of a plant, which in turn is primarily governed by circadian rhythms. However, the interconnection between electrokinetics and the diurnal biological clock is yet to be understood. In this work, we unraveled the electrokinetics in response to the diurnal variations of a plant. Experiments conducted on water hyacinth stem indicate a cyclic variation of streaming potential synchronized with the changes introduced by circadian rhythm. In further efforts toward understanding the variation of streaming potential at different flow conditions, experiments were conducted on excised stem segments of Dracaena sanderiana, where the generated potential was studied against varying flow rates with different constitutive features of the flowing electrolyte. Notably, the resulting streaming potential from the flow of electrolytic solutions of different ionic strengths, species, and pH was found to align well with the fundamental premises of electrokinetics. These results are likely to expand our current knowledge of plant hydraulics by diligently examining the electrokinetics involved in the flow circuits of plants that undergo cyclic variations in close association with the circadian rhythms.

Oil absorbent based on lauryl methacrylate grafting onto cellulose of water hyacinth (Eichhornia crassipes)

AbstractIn this article, a novel oil‐absorbent polymer was synthesized by graft polymerization of lauryl methacrylate (LMA) onto water hyacinth (WH) using 2,2′‐azobisisobutyronitrile (AIBN) as initiator and divinyl benzene (DVB) as a crosslinking agent. The effects of initiator content, LMA content, reaction temperature, reaction time, and crosslinker content on the superabsorbent polymer were investigated. The prepared graft copolymer WH‐g‐LMA was analyzed using FTIR, SEM, XRD, and TGA. In the presence of the better cross‐linker DVB (1.5%) and contact time of about 25 min, the maximal Q (oil sorption capacity) of co‐polymer towards crude and Soybean oils is 23.68 and 25.72 g g−1, respectively. The Q is reduced when sorbent dosage increased, but it increases with increasing the temperature and reaches a maximum of 40 °C. The reusability of co‐polymer is characteristic of 7 sorption/desorption cycles.

Effects of water hyacinth compost and biological agents (Trichoderma sp) on the growth and yield of shallots (Allium ascalonicum L.) in dry land

Shallot (Allium ascalonicum L.) is one of leading vegetable commodities intensively cultivated by farmers for a long time, including farmers in East Nusa Tenggara (ENT). The purpose of this study was to produce water hyacinth compost with ability to interact with Trichoderma sp. in order to improve the shallot bulb quality cultivated in dry land. This factorial experimental research was arranged in a Split Plot Design with 10 treatments and 3 replications. There were 10 treatment combinations with 30 experimental plots. Two factors were tested in this research. The first factor was the water hyacinth compost as the main plot, namely: 15 ton ha⁻¹ water hyacinth compost (K1) and without water hyacinth compost (K2), while the second factor as a sub-plot was the concentration of Trichoderma sp., consisting of watering with plain water (as control) of 100 mL(P0), watering with a concentration of Trichoderma sp. 5 mL.L⁻¹ (P1), watering with a concentration of Trichoderma sp. 10 mL.L⁻¹ (P2), watering with Trichoderma sp. concentration 15 mL.L⁻¹ (P3) and watering with Trichoderma sp. 20 mL.L⁻¹ (P4). The treatment of water hyacinth compost fertilizer at 15 tons ha⁻¹ with a concentration of Trichoderma sp 20 mL.L⁻¹ resulted in the highest number of shallot leaves (84.27 strands) and tillers (10.82). The shallot bulb weight per plot was 2455.33 g, and the number of bulbs per plot was 350.40 bulbs.

Nutrient Digestibility of Non-conventional Protein Sources Blend in African Catfish, Clarias gariepinus (Burchell, 1822) Post Juveniles Using Novel Aquafeed Formulation Software

In this study, the growth performance, carcass composition, and apparent digestibility coefficient of African catfish, Clarias gariepinus, were evaluated in relation to different non-conventional protein sources blends diets that were formulated using a novel feed formulation software (FUTA AQUAFEED). Diet 1 served as the control diet, and the other four experimental diets (Diets 2 through 5) included non-conventional protein sources such blood meal, water hyacinth, palm kernel cake, palm beetle meal, blackfly meal, water fern, and Moringa. The gross composition of the experimental feeds exhibited notable variations in nutrient content. The crude protein content in the diets were iso-nitrogenous. Analysis of the composition of the carcass showed that diets varied significantly. Diet 5 had the highest fat content (10.66%), while Diet 3 had the highest crude protein amount (61.57%). Growth performance parameters such as initial and final weights, weight increase, feed conversion ratio (FCR), specific growth rate (SGR), and protein efficiency ratio (PER) exhibited diverse patterns. Diet 5 produced the greatest final weight (324.00 ± 122.94 g) and weight gain (173.32 ± 96.06 g), suggesting that the varied protein blend may have advantages. Dietary differences were seen in the apparent digestibility coefficients of crude protein and lipids. The crude protein digestibility coefficient (90.68%) was best in Diet 3, while the crude lipid digestibility coefficient (92.00%) was highest in Diet 1. In conclusion, the inclusion of unconventional protein sources in the diets of C. gariepinus affects both their growth performance and nutritional makeup. Through the incorporation of alternate protein sources into fish diets, the findings offer insights for improving aquaculture techniques and advancing sustainability.

Silane and fluorine free facile hydrophobicization of water hyacinth biomass for oil-water separations

As the adverse effects of using plastics and perfluorinated alkyl substances become more apparent, there is a growing need for sustainable hydrophobic products. Cellulose and its derivatives are the most abundant and widely used polymers, and cellulose-based products have great potential in industries where plastics and other hydrophobic polymers are used, such as stain-resistant fabrics, food packaging, and oil-water separation applications. In this study, we extracted cellulose from water hyacinth (WH) biomass, known for its negative environmental impact, and converted it into hydrophobic cellulose. This addresses the issue of managing WH waste and creating an environmentally friendly hydrophobic material. Initially, aldehyde groups were introduced through oxidation with periodate, followed by direct octadecyl amine (ODA) grafting onto dialdehyde cellulose (DAC) via a Schiff base condensation. The resulting ODA modified cellulose (ODA-C) was dispersed in ethanol and used to coat various materials, including cotton fabric, cellulose filter paper, and packaging paper. The modified materials showed excellent hydrophobicity as measured by their water contact angles (WCAs), and the application of the coating was demonstrated for oil-water separation, stain-resistant hydrophobic fabric, and paper-based packaging materials. FTIR, XRD, and WCA analysis confirmed the successful modification of cellulose. A high separation efficiency of 99% was achieved for diesel/water separation using modified filter paper (MoFP), under gravity. On application of the coating, cotton fabric became hydrophobic and resisted staining from dye, and paper-based packaging materials became more robust by becoming water-resistant. Overall, the facile synthesis, low cost, high efficiency, and use of environmentally friendly sustainable materials make this a promising strategy for hydrophobically modifying surfaces for a wide range of applications while reducing the menace of water hyacinth.

Pontederia crassipes Biosynthesised Silver Nanoparticles (AgNPs), Characterisation and Activity against Multidrug-Resistant Microbes

Introduction: Pontederia crassipes (water hyacinth) has been singled out as one of the major causes of enormous economic and ecological losses to tropical water systems and habitats. Almost impossible to eradicate, the ominous species is characterized by rapid multiplication, giving rapid and extensive spread that can choke entire rivers and water bodies. However, vast, diverse bioactive secondary metabolites are found in P crassipes which exhibit an expansive assortment of antibacterial properties used in traditional medicine. The rapid emergence of Multi Drug Resistant (MDR) pathogens to common drugs is a pandemic of global proportions. Global health institutions are calling for a coordinated, global action plan to develop new biomaterials to combat the rising threat by MDR strains and improve treatment outcomes and save lives. This study proposes consumption of the water hyacinth lily species through a novel, material biosynthesis approach not only to manage the aquatic infestation but to develop advanced multifunctional, anti-microbial Silver nanoparticles through bio-reduction and capping of Silver salts targeted at MDR microbes. Methodology: After screening for active phytoconstituents of P.crassipes. The Biosynthesis of Novel AgNPs mediated by phenolic, antibacterial lyophilized hydro-ethanolic extracts from P crassipes as both bioreduction and capping agents was investigated. The resultant AgNPs characteristics, toxicological profiles and the antibacterial effects on 10 common microbes including MDR bacterial strains were evaluated. Observations and Results: TEM revealed that cubic and spherical nanometric AgNPs structures were successfully synthesized with particle size range from 10-60nm. With an average zone of inhibition of 29mm and an MIC of 6.25 µg/ml .The nanoparticles were efficacious against selected MDR strains and common infectious bacterial strains tested. In-vivo acute oral toxicity evaluations confirmed the safety of P crassipes. Conclusion: Biogenic P.crassipes mediated AgNPs are feasible, safe and efficacious and have immense potential for optimization into efficient broad spectrum MDR antibacterial agents.b

Biotic and abiotic factors driving water hyacinth, Pontederia crassipes, phenology in Nyanza Gulf, Lake Victoria, Kenya

While isolated patches of water hyacinth have persisted in most parts of Lake Victoria since the rapid decline in biomass beginning in 1999/2000, Nyanza Gulf has maintained extensive but cyclical coverage over the years. High water hyacinth productivities were found to coincide with the western region associated with upwelling and regenerated nutrients, and also with periods of complete lake turnover. River discharge sites, which are numerous in the eastern region, expressed relatively low water hyacinth productivities. High productivity meant better nutritional quality, a state preferred by the Neochetina weevils. Although the difference in productivities between the eastern and western regions were statistically insignificant, the feeding scars were notably different. This implies that any slight change in water hyacinth’s nutritional quality as a result of change in resource water quality, significantly affects the weevil’s productivities. During complete lake turnover, water hyacinth productivity is highly enhanced, likely due to upwelling of hypolimnetic nutrient enriched waters with subsequent spontaneous weevil invasion. During times of such high nutrient quality, the rates of leaf turnover outstrips the herbivory by the weevils. The nutrient dynamics from primary sources coupled with secondary regenerated loads through lake turnovers influences the water hyacinth’s varying nutritional quality and weevil population, which ultimately determines the water hyacinth phenology within the semi-enclosed Nyanza Gulf. The objectives of this study were to study the spatial influence of resource water quality to the consumer water hyacinth productivity and how temporal hydrologic dynamics drives its cyclicity.