bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of pH and Light Intensity on the Growth of Dunaliella Salina
Authors: Dilshan W.L.T.  , Asanthi H.B.  , Maithreepala R.A.  , Atapaththu K.S.S.  , Costa A.M.K.C.J.  , Suranga D.K.A.I.  
Published: February 2024

Dunaliella salina is a unicellular halophilic green alga dominantly found in salt lakes, and high saline ponds in slatterns all over the world. A rigid cell wall is absent in D. salina while the cells are covered by mucous materials that are enclosed by a thin elastic plasma membrane. This species has both environmental and economic validity as they are capable of producing β–carotene during photosynthesis. Synthesis of β–carotene in D. salina is a function of environmental factors, and thus, the present study was designed to study the effect of pH of the medium and light intensity on the growth of D. salina. The Algae sample was collected from a crystalizing pond of Hambantota Saltern, Sri Lanka, and a monoculture was maintained under suitable laboratory conditions. The seawater sample with pH 7.66 was used to prepare a series of pH using sodium carbonate anhydrous. These cultures were exposed to a series of pH (7.66, 8.0, 8.50, and 9.0) at two light intensities (885 lux and 200 lux). All experimental setups were maintained at 25oC with the photoperiod of 12h light and 12h dark. Four replicates of each pH medium were arranged into a 4×4 setup of flasks for each light intensity and the experiment was conducted for four weeks. At the end of the fourth week, the pH level of all flasks ranged from 8.27 to 8.53 due to the self-adjustment of the pH level in the culture medium in parallel to algal growth. The maximum growth was reflected by the highest absorbance of 1.46 at 750 nm. Taken together, our findings revealed that the optimum pH range and light intensity for culturing D. salina is 8.27-8.53 and 885 lux respectively. This study recommends further research on culturing of D. salina for extracting the bioproduct of β -carotene at various light intensity levels.
Keywords: Cell density, β –carotene, Light intensity, Self-adjusted
Effect of Natural IAA Produced by Streptomyces Strain ACM37 on Seed Germination and Seedling Growth
Authors: Gamlath A.G.N.N.A.S.  , Abayathunga T.P.  , Widana Gamage S.M.K.  
Published: February 2024

Biofertilizers play an important role in sustainable agriculture by improving soil fertility, crop tolerance and crop productivity. In this context, exploitation of plant growth promoting rhizobacteria with various beneficial properties is challenging. This study aimed to investigate the plant growth promoting activity of indole-3-acetic acid (IAA)-producing actinomycetes strain, Streptomyces ACM37 on the seed germination and seedling growth at early stage. The ACM37 was grown in starch-casein broth for 7 days at 28° C, 80 rpm and supplemented with 50 mg/l L- tryptophan to induce IAA production. After 7 days, IAA concentration in cell-free culture broth was quantified by following the Salkowski's method and it was 50 mg/l. Seed germination and seedling growth of cowpea (Vigna unguiculata) and rice (Oryza sativa L.) at different concentrations of IAA were estimated as % seed germination, number of roots, primary root length and length of hypocotyl. Initially, seeds were surface sterilized with 10% (v/v) NaOCl and soaked in 10, 20, 30, 40 and 50 mg/l crude IAA preparations for 1 h at 30° C. As controls, seeds were soaked in sterilized distilled water (SDW) and 50 mg/l synthetic IAA. Ten seeds per each treatment with three replicates were placed on 0.8% (w/v) water-agar in Petri plates and incubated in dark at 30° C. The % seed germination of ACM37-IAA-treated cowpea and rice seeds was enhanced at all concentrations compared to SDW and synthetic IAA treatments after 3 days. The highest 100% germination of cowpea was given at 10 mg/l IAA while it was 96.67±3.33% in>30 mg/l IAA in rice. Similarly, there was a significant (P<0.05) increase in primary root length and number of lateral roots in cowpea at 10 mg/l of ACM37-IAA. Overall, ACM37 showed significant plant growth promotion in cowpea at low concentration (10 mg/l) of IAA whereas there was a significant (P<0.05) reduction at high concentrations (>10 mg/l). On the other hand, there was no apparent increase in all growth parameters except seed germination in rice at all concentrations. It appears that high concentrations of ACM37-IAA may be required to promote plant growth in rice. Overall results highlight that plant growth promotion activity of ACM37 varies at different IAA concentrations and different plant species, probably between monocot and dicot species. Therefore, ACM37 has potential application as a plant growth promoting agent in biofertilizers and plant growth inhibiting agent in bioherbicides at certain IAA concentrations.
Keywords: Actinomycetes, Biofertilizer, Bioherbicide, IAA
Removal of Crystal Violet Dye in Textile Wastewater Using Rice Husk Biochar
Authors: Pabasara W.G.A.  , Premadasa A.G.K.E.  , Madushika J.W.A.  
Published: February 2024

Crystal Violet Dye (CVD) is a water-soluble, hazardous organic dye that causes adverse health issues and environmental pollution. This dye was mostly added to wastewater by the textile industries. Treatment of CVD-contained wastewater has become a great challenge due to high investment and operating costs and inefficiency in dye removal of conventional methods such as biological degradation and chemical oxidation. So, the main purpose of this study is to investigate the CVD removal ability of Rice Husk Biochar (RHB). The experiment procedure was designed to determine the influence of initial CVD concentration, adsorbent dosage, pH, contact time, and temperature on dye removal. RHB was prepared by pyrolysis process at 700o C for 3h at a constant heating rate of 10o C min-1 in a muffle furnace. Adsorption of CVD by RHB was verified by performing Fourier Transform Infrared spectroscopy. The concentration of the remaining dye after adsorption studies was calculated using Ultra-Violet visible spectroscopy. According to the results, the dye removal efficiency increased with the RHB amount, but the rate of this increment decreased at higher RHB dosages. The highest dye removal efficiency of 97.33% was recorded at 1.5 g RHB amount. In the effect of initial CVD concentration, the efficiency increased up to 600 mg/l and then decreased and the maximum removal efficiency was 96.77%. pH value has no significant effect on dye removal and the highest efficiency of 97.3 % was recorded at pH 4. Further, as the contact time increased, the dye removal increased until it reached an equilibrium state at 60 minutes with 92.03% efficiency. Moreover, when raising the temperature, the adsorption of CVD by RHB marginally increased. According to the kinetic studies, the experimental data followed pseudo- second-order kinetic models than pseudo-first order. Further, adsorption equilibrium data well fitted both Freundlich and Langmuir isotherm models so that it can be assumed that both monolayer and multilayer adsorption of CVD in RHB surface. Thermodynamic parameters such as Gibbs free energy and enthalpy change were calculated, and all values were recorded as negative implying adsorption was favorable and spontaneous and the process was exothermic. In conclusion, the optimum dye removal was recorded at 350 C and pH 4 with an initial dye concentration of 600 mg/L and adsorbent dosage of 1.5 g. Thus, this study concluded that RHB could be utilized as a cost- effective, eco-friendly, and affordable adsorbent for the removal of CVD from wastewater with over 90% dye removal efficiency.
Keywords: Crystal violet dye, Rice husk biochar, Textile industry, Adsorption
On-water Catalyst-free Synthesis of 3-Alkenyl Oxindoles
Authors: Kumarasinghe K.G.U.R.  , Samaradiwakara D.M.T.A.  
Published: February 2024

3-Alkenyl oxindoles are key structural motifs in organic chemistry with a wide range of applications mainly in the pharmaceutical industry, due to excellent biological activities such as anti-inflammatory, antiviral, antibacterial, and anticancer properties. With the discovery of the importance of oxindole derivatives in the pharmaceutical industry, demand for sustainable protocols for the synthesis increased as most classical methods have their limitations and flaws. In this study on-water, catalyst-free, atom-economical green approach was developed for the synthesis of 3- alkenyl oxindole derivatives using oxindole and aldehyde as starting materials. The reaction between oxindole and benzaldehyde was conducted on water under catalyst-free conditions. Interestingly, 100% conversion was observed when the reaction was carried out for 24 hours at 100° C. As the next step, the applicability of the developed approach was proven for different aldehydes. Furaldehyde, cinnamaldehyde, and vanillin were used as the aldehydes to synthesize 3- alkenyl oxindole derivatives, and the isolated yields were obtained as 77%, 54%, and 51% respectively. The desired product formation was confirmed by comparing the Rf value of the product with that of the previously synthesized well-characterized compounds; 3- benzylideneindolin-2-one, 3-(furan-3-methylene)indolin-2-one, 3-(3-phenylallylidene)indolin-2- one, and 3-(4-hydroxy-3-methoxybenzylidene)indolin-2-one using Thin Layer Chromatography. Further characterization was done by Fourier-transform infrared (FT-IR), Ultraviolet-visible (UVVis), and Nuclear Magnetic Resonance (NMR) spectroscopic techniques. In further optimization steps, the reaction was performed using surfactants as the catalyst. By adhering to the green chemistry principles different sources of biosurfactants were used including Acacia concinna pods, Sapindus emarginatus fruit pericarp, Dillenia retusa fruit pericarp, and Trigonella foenumgraecum seeds. In order to compare the effect of biosurfactants, a synthetic surfactant, sodium dodecyl sulfate (SDS) was used as the catalyst. When the reaction was carried out for 21 hours at 100 °C using fruit pericarp of Sapindus emarginatus as the source of biosurfactant, 100% conversion was observed. Using water as the solvent, readily available starting materials, higher yield, and eco-friendliness and catalyst-free conditions suggest the possible use of the developed method for large-scale preparations of 3-alkenyl oxindole derivatives.
Keywords: Green protocol, Oxindole derivatives, Surfactant, On water synthesis, Catalyst-free
State of Surface and Vertical Salinity in Puttalam Lagoon during North-East Monsoon
Authors: Perera H.A.S.D  , Jayathilake R.M.  
Published: February 2024

Puttalam Lagoon which covers 226 km2 located in Sri Lanka‘s Northwest coast, plays an important role in aquaculture and lagoon capture fisheries. Kala oya and Mee oya are the major freshwater sources which empties into the Lagoon by eastern bank. Salinity variability is an important environmental variable in lagoon system that has an impact on aquaculture and aquatic resources. During the Northeast monsoon (NEM) in 2021, the spatial and vertical fluctuation of salinity in the lagoon was studied using SBE 19plus V2 CTD profiler. Field measurements show that the vertical salinity stratification in the lagoon was substantial during the study period. The lagoon has a significant spatial variability of salinity, ranging from 15 psu to 26 psu and Kala Oya river mouth has a salinity of 22 psu which impacted by freshwater and sea water circulation. The Salinity stratification in eastern section of the lagoon where the Kala Oya and Mee Oya streamflow reach is observed with surface salinity of 15 psu. During the NEM season, the average discharge of Kala Oya and Mee Oya to the lagoon was 10.8 m3/s and 9.4 m3/s, respectively, with a mean monthly precipitation of 48.89 mm. Fresh water from the Kala and Mee oya rivers flows into the lagoon during the season, while low evaporation and significant rainfall led the salinity to decline during the wet season, influencing the structure and function of lagoon ecosystems. The study reveals that a significant area of the lagoon is covered by the 20-30 psu salinity range, which is more appropriate for brackish water fisheries, particularly for shrimp and prawns during NEM.
Keywords: Salinity, CTD profiling, Northeast Monsoon, Freshwater
Variation of Geochemical Properties of Soils in Tropical Lowland Rainforests in Sri Lanka
Authors: Bandara H.M.K.S.  , Herath H.M.S.K.  , Samarakoon S.M.T.N.  , Chandrajith R.L.R.  , De Costa W.A.J.M.  
Published: February 2024

Tropical lowland rainforests (TLRFs) of Sri Lanka are considered as diverse ecosystems which play a vital role in climate change mitigation. In recent years, increasing deforestation leads to diminishing their potential ecosystem roles. For efficient forest conservation, knowledge of both above- and below-ground characteristics of TLRFs is required. Currently, above-ground information on TLRFs is sufficiently available but the details on the below-ground characteristics are limited. Therefore, this study was carried out to investigate pedo-geochemical properties of lowland rain forests of Kanneliya (KDN) and Pitadeniya, (PTD) in Sri Lanka. Four sampling plots with 1 ha in size (KDN1, KDN2, PTD1 and PTD2) were established, selecting altitudes of 117, 174, 509, and 618 m asl, respectively. Five representative near-surface (up to 25 cm) samples were collected from each plot for the investigation. Soil pH, electrical conductivity (EC), and cation exchange capacity (CEC) were measured while soil organic matter (SOM) content was determined by (i) Walkey-Black (WB) and (ii) Loss on ignition (LI) methods. Data were analysed by ANOVA and means were compared using Duncan‘s test. All measured parameters were significantly different (P<0.05) among the sampling plots. Soil pH and EC values were ranged between 3.43– 3.78 and 0.28–0.44 dS m-1, respectively. The highest CEC was recorded in PTD2 (11.09±3.44 cmol(+)/kg) whereas the lowest was in PTD1 (5.31±1.26 cmol(+)/kg). The highest SOM was recorded in PTD1 (17.71±4.42% in WB, 18.04±3.98% in LI) whereas the lowest was noted in PTD2 (5.81±3.07% in WB, 8.21±2.13% in LI). According to the comparison made between WB and LI methods, LI method recorded higher SOM content. The actual SOM and volatilizable water in hygroscopic mineral fractions might be the reason for the higher values in LI method. All acquired data were compared with standard interpretation data and accordingly, soils of the measured TLRFs are acidic, non-saline and non-reduced with sufficient soil aeration. Even though, TLRF vegetation produce high amount of biomass, soil CEC and SOM contents are low in the study area due to rapid microbial decomposition and absorption of dense vegetation. There was no linear relationship between measured parameters and altitude. Overall, measured soil chemical properties can be considered as ideal indicators of TLRFs conservation and therefore, it needs to be correlated with above-ground properties for understanding the behaviour of TLRFs responding to conservation strategies.
Keywords: Forest conservation, Soil chemical properties, Soil organic matter content, Tropical lowland rainforest
Comparative Study of Soil Nutrients in Selected Paddy Lands in Wet Zone Treated with Organic and Chemical Fertilizers
Authors: Pemathilaka A.U.S.  , Munasinghe M.L.A.M.S.  
Published: February 2024

In Sri Lanka, paddy consumes the most significant part of chemical fertilizers and accounts for approximately 50 percent of the widespread use of chemical fertilizers. With the immediate banning of inorganic fertilizers, there was a huge argument between the government and the farmers about organic farming. Since the soil fertility change takes a long time, the impact of long-term application of the same fertilizer should be assessed. Field experiments were conducted in six selected paddy fields in wet zone considering fertilizer type and rice variety. Total 30 samples from each site were collected and soil initial nitrogen (N), phosphorus (P) potassium (K), Organic C, and composition of used fertilizers were analyzed. Nutrient status compared using critical, optimum ranges, and general management practices are discussed. This study revealed that the total N level in all the sites varies near the critical level and is inadequate to produce expected yields. Soil organic C (3.8-6.7%) and N (0.06-0.2%) levels in organic sites were higher than the chemical sites (0.09-0.19N%, 1.4-2.1C%). Phosphorus level is below the critical level (0.9-8.4 mg/kg) in organic sites, and varies from medium to high (7.5-27.0 mg/kg) in chemical sites. The sites using chemical fertilizers showed excessive K (395-480 mg/kg), and organic sites were below the optimum range (82-92 mg/kg). According to the fertilizer analysis, organic fertilizers are rich in organic C (40-90 g/kg), while organic C is absent (0%) in chemical fertilizers. All the other nutrient amounts are very low (N:0.7-19.3 g/kg, P:0.06-0.8 g/kg, K:33.2-15.4 mg/kg) in organic fertilizers, and the composition is unstable. Chemical fertilizers have an exact composition of nutrients and can easily be applied at the particular growth stage of the plant which is beneficial. An external supply of essential soil nutrient through organic or chemical fertilizer sources is required to produce expected yields. Regular and continuous monitoring of soil quality, pre-nutrient assessment of organic fertilizers, site-specific fertilization, and proper agronomic practices are highly recommended. These results will be beneficial in selecting or manufacturing suitable fertilizer type/types for paddy cultivation, including bio-fertilizers.
Keywords: Organic fertilizers, Status of soil nutrients, Soil fertility, Rice varieties
Impacts of Organic and Non-organic Paddy Farming Practices on Surface Water Quality in Selected Areas
Authors: Fernando N.D.S.M.  , Godakumbura P.I.  , Prashantha M.A.B.  , Cooray A.T.  
Published: February 2024

Paddy (Oryza sativa L.) cultivation plays major role in Sri Lanka. Mainly Organic and Non-organic paddy farming methods are conducted. Organic paddy farming method only used organic fertilizers and non-organic paddy farming method used chemical fertilizers which are Urea, Triple Super Phosphates. Therefore, farming practices can be affected to the surface water quality creating various health hazards. The study was conducted from November 2021 to February 2022 (Maha season) to assess the impact of organic and non-organic paddy farming practices on surface water quality in Wallewala, Homagama, and Kottawa paddy agricultural lands by analyzing pH, EC, TDS, DO, BOD, COD, total hardness, nitrate, nitrite, phosphate, sulfate, chloride, potassium, zinc, and chromium. Wallewala is newly created environment sensitive agricultural land in less human influence. Both organic and non-organic paddy lands are in that area. Kottawa paddy lands are cultivated only chemical fertilizers and the Homagama paddy lands are cultivated by organic fertilizers. Randomly, six and nine surface water samples were collected from paddy irrigated systems in Wallewala area represent to organic and non-organic paddy lands respectively. Randomly, five and six surface water samples were collected from paddy irrigated systems in Homagama Organic, and Kottawa non-organic paddy lands respectively. The water from both paddy systems, min pH (5.25±0.04), max EC (315±1.00 μScm-1 ), min DO (6.13±0.06 mgL-1), max BOD5 (2.82±0.06 mgL-1), max sulfate (205.76 ppm), max chloride (45.91 ppm), max K (5.63 ppm), and max Zn (0.12 ppm) were found, while the study revealed that all the water quality parameters were not exceeded the reported ambient water quality standards for inland waters in Sri Lanka for irrigation purposes. Further EC, TDS, COD, total hardness, sulfates, chloride, potassium, and zinc were greater in non-organic paddy lands in both Wallewala and Kottawa areas. According to the obtained data, there was no water pollution from the paddy cultivation in respective areas. But these results indicate that water quality parameters vary with the utilized fertilizers.
Keywords: Paddy cultivation, Water quality, Organic paddy farming, Non-organic
A Quality Review of EIA: A Comparative Study of State-Funded and International Aid Agency-funded Development Projects in Sri Lanka
Authors: Vinasithamby R  , Vimaladhas N.  , Vimaladhas V.  
Published: February 2024

A development project's environmental impact assessment (EIA) is a tool for mitigating the effects on the environment and promoting sustainable development. EIA is an expensive and professionally engaged process that involves the public. Many countries around the world have long-standing laws in place connected to this topic, as well as solid knowledge and experience. One persistent argument against the efficacy of EIA in developing nations is that the procedure and quality differ from country to country. The International Aid Agencies (IAA) have their guidelines for protecting the environment while following local environmental assessment standards for any financing requirements. IAA involvement in the EIA process might significantly affect how well- written EIA reports are. To evaluate the assessment quality, six EIA reports from state-financed development projects (SL-EIAs) and another six development projects EIAs funded by the IAA (IAA-EIAs) in Sri Lanka were randomly chosen. LeeCooley review package (1990) was used to evaluate the Environmental Impact Statements (EIS) of each EIA. In this investigation, it was discovered that IAA-EIAs and SL-EIAs had a significant difference in overall quality. IAA-EIAs show values that range from highly satisfactory to satisfactory and each share 50 percent, whereas SL-EIAs indicate 83 percent satisfactory and 17 percent of borderline quality. In comparison to the SL-EIAs, all four review areas of the IAA-EIAs performed notably well. While the SL-EIA shows good to borderline quality (0.66-0.72), all evaluated IAA-EIA reports reveal highly satisfactory to satisfactory (0.81-0.93) quality. The engagement of IAA in the environmental assessment has a considerable impact to improve assessment quality in comparison to the only domestic assessment. Finding the weak area in the SL-EIA process and adhering to the IAA standards would elevate the standard of the report.
Keywords: EIA quality, Review, International Aid Agency, Development projects