University of Sri Jayewardenepura: Journals & Proceedings
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Comparative Study of Bisphenol-A and its Analogue Bisphenol-S on Growth and Condition Factor of Juvenile Zebrafish (Danio rerio)
Get PDFBisphenol-A is a synthetic estrogen highly used in the production of polycarbonate plastics and epoxy resins in plastic industry world-wide. Bisphenol-A presents as a ubiquitous environmental contaminant in all ecosystems. Bisphenol-A is an endocrine disruptor which affects the growth, development and physiology of living organisms. Therefore, bisphenol-S has been introduced as a safe alternative to bisphenol-A and it has become the widely used bisphenol-A substitute. Bisphenol-S has also been identified as an endocrine disruptor and emerging environmental contaminant. Therefore the safety of bisphenol-S substitution has become questionable. Thus, this study was carried out to comparatively assess the impacts of bisphenol-A and bisphenol-S exposure on growth and condition factor of zebrafish (Danio rerio). After 7-days acclimatization period, twenty juvenile zebrafish of 67 dpf (days post fertilization) of age were treated 35 days with 10 μg/L and 100 μg/L of bisphenol-A, bisphenol-S and with treatment control in triplicate tanks. Mean body length, weight, specific growth rate and condition factor of fish were evaluated. Mean body weight increment of zebrafish under 100 μg/L of bisphenol-S and bisphenol-A were significantly different from the treatment control (p<0.05, One way ANOVA, Tukeys pairwise Comparison). The mean body length increment and specific growth rate were not significant under both concentrations of bisphenol-S and bisphenol-A with treatment control (p>0.05). However, the condition factor of fish under both concentrations of bisphenols were significantly less than control (p<0.05). The condition factor of fish under comparable concentrations of bisphenol-S and bisphenol-A were not statistically significant. Therefore, it can be concluded that exposure to environmental concentrations of both types of bisphenols could affect the wellbeing of juvenile zebrafish. Based on the findings, bisphenol-S cannot be recommended as a safe substitution to bisphenol-A. Yet, more comprehensive studies are recommended to evaluate relative effect of bisphenol-S on freshwater ecosystem health.
Keywords: Body length, Body weight, Condition factor, Bisphenol-A, Bisphenol-S, Zebrafish, (Danio rerio) 
Mycoremediation Approach to Green Air: Phenanthrene and Anthracene Degrading Ability by Fusarium solani Isolate P11M-46
Get PDFThere are many health issues associated with air pollution that are rapidly increasing with time across the globe. Among many air pollutants, polycyclic aromatic hydrocarbons (PAHs) are of particular concern because of their carcinogenicity, genotoxicity, and long persistence in the environment. The majority of these PAHs release into the air through anthropogenic activities and natural sources. After releasing into the air, PAHs usually return to the ground due to their high molecular weight. These hydrocarbon depositions can be categorized as wet or dry depositions. One of the most prominent deposition surfaces of these pollutants is the phyllosphere. Microorganisms such as fungi perform a key role in PAHs elimination through bioremediation processes. Epiphytic fungi such as Fusarium solani isolate P11M-46 utilizes the deposited phenanthrene and anthracene on the phyllosphere and convert those PAHs in to non-toxic levels. The aim of this study was to evaluate the ability of F. solani isolate P11M-46 to degrade phenanthrene and anthracene, through a mycoremediation approach. Leaf samples were collected from Panchikawatta, Orugodawatta, Pettah, Maradana, Colombo Fort, and Sapugaskanda urban areas in Sri Lanka. Furthermore, PAH degradation ability of isolated F. solani isolate P11M-46 was confirmed through High Performance Liquid Chromatography (HPLC). The effects of by-products produced from the biodegradation process on living beings were evaluated using Artemia salina and the by-products were identified using Gas Chromatography and Mass Spectrometry (GCMS). According to HPLC results, F. solani isolate P11M-46 showed 68% of degradation percentage in phenanthrene while exhibiting 76% degradation in anthracene within 6 days. The GCMS analysis confirmed that the by-products were Phenol, 2-(phenylmethyl) from phenanthrene and 9, 10-anthracenedione from anthracene. Toxicity assay with A. salina confirmed that these byproducts were not toxic to the phyllosphere. The findings of the present study revealed the potential use of phyllosphere F. solani isolate P11M-46 in the remediation of environmental pollutants phenanthrene and anthracene. And also the by-products produced during their degradation mechanism were also confirmed as nontoxic compounds. Therefore, F. solani isolate P11M-46 could be effectively used in the bioremediation of phenanthrene and anthracene in polluted environments as a bioremediator.
Keywords: Polycyclic aromatic hydrocarbons, Bioremediation, HPLC, GCMS, Toxicity 
Ascertainment of Photosynthetic Biomass Curves in the Early Growth Stages of Selected Dominat Native and Endemic Plant Species in Lowland Rainforest Ecosystems, Sri Lanka that as a Proxy for Value Primary Ecosystem Services and towards Conservation
Get PDFThe lowland rainforests play a significance role in maintaining the rich biodiversity of threatened endemic and native species of flora. However, the physiognomy of many species is still poorly known. The main objective of this study was to established the gains in photosynthetic Biomass (PB) during the early growth phases of three native and endemic tree species Garcenia quaesita, Dipterocarpus zeylanicus and Artocapus nobilis, which are frequently found in the low land rainforest ecosystems in south-west Sri Lanka. The study was based on field data collection and through observations based on empirical measurements which focused on PB accumulation in the early growth stages of above tree species. The sampled individuals were found in the reforested site in Hinduma, Sri Lanka and Sampling was carried out in four sites which represented the growth at 1, 2, 3 and 4 years. Purposive sampling was carried out and 30 individuals from each and individual age group as mentioned above, totaling 360 individuals of the plant species. Fresh weight was measured from collected leaves and analyzed to derive PB curves using statistical software Minitab version 15. Oxygen production (1 g of PB gives 0.4 g of Oxygen) was quantified using the measured PB value applied to the standard allometric equation. PB and Oxygen production of selected tree species demonstrated an exponential growth after the age of 3 years. Results shows that at the end of 4th year D. zeylanicus produce highest PB value, i.e., 2,483.55 grms and then 550.92 and 421.36 grams occupied by A. nobilis and G. quaesita. Also, PB and Oxygen production had a significant relationship with the age. In conclusion all the selected species under the given climatic conditions shows an increasing rate of PB, and oxygen production with age up to 3 years with an exponential growth thereafter. The findings of this study will be used to explored and included in the contractual process of value Primary Ecosystem Services (PES) hence all the PES derivatives such as carbon sequestering values and oxygen production based on the PB value of that given plant species. Therefore, it creates new scientific proven records to archive economic opportunities, which are not still identified and value of primary ecosystem services of tree dominated ecosystems/land uses to achieve national green economic policy management objectives. Such an economy described above, can generate new ecosystem servicing values and socioeconomical benefits which, at the same time, promotes conservation of these species and their unique environments.
Keywords: Conservation, Green economy, Lowland rainforests, Photosynthetic Biomass, Primary ecosystem services 
A Comparison of Resources Usage for Two White-Leg Shrimp (Penaeus vannamei) Farming Systems (Earthen Pond System and Round Tank System)
Get PDFShrimp farming plays an important role in providing nutritious food and generating livelihoods for many millions of people worldwide. Asia is the biggest producer of shrimp contributing nearly 80% of the global shrimp aquaculture production. Black tiger shrimp (Penaeus monodon) is the main brackish water aquaculture species in Sri Lanka before 2018. White-leg shrimp (Penaeus vannamei) was a new species that was introduced in 2018 expecting a rapid increase in production in the country. Shrimp farming is classified into several categories: extensive, semi-intensive, intensive, and super-intensive based on the intensity of management practices such as stocking density, supply of feed and fertilizer, and management of water qualities. The round tank system is round-shaped and is a type of lined pond that uses an impermeable geomembrane for the retention of water. It belongs to the super-intensive category. The earthen pond is a water body that is basically enclosed by the earth. It belongs to the intensive category. The purpose of this study was to assess the amounts of land, water, and energy required per ton of harvested shrimp in two different production systems and identify the most sustainable system that is used minimum natural resources. The round tank system is located in the Erukkalampiddy area in the Mannar district, Sri Lanka. The earthen pond system is located in the Maikkulama area in the Puttalam district, Sri Lanka. Data on water usage, electricity usage, land area usage, and weight of harvested shrimp were collected during two cycles of production from August 2021 to May 2022. The t-tests were performed to compare resource usages. Land usage of the earthen pond system (950.00 m2/t shrimp, 1266.67 m2/t shrimp) is significantly greater than the round tank system (190.77 m2/t shrimp, 139.33 m2/t shrimp). Water usage of the earthen pond system (950.00 m3/t shrimp, 1266.67 m3/t shrimp) is significantly greater than the round tank system (190.77 m3/t shrimp, 139.33 m3/t shrimp). Energy usage of the round tank system (473.84 kWh/t shrimp, 591.46 kWh/t shrimp) is significantly greater than the earthen pond system (119.91 kWh/t shrimp, 154.78 kWh/t shrimp). It concludes that less land and water resources and high energy usage are required for a round tank system compared to an earthen pond system. Although establishing a round tank system will need more capital, compared to that of an earthen pond system, it is evident that the round tanksystem is more environmentally sustainable.
Keywords: Shrimp farming, Round tank system, Earthen pond system, White-leg shrimp (Penaeus vannamei
Scaling Up Above-Ground Biomass for Khaya senegalensis from Tree Level to Stand Level Using Sentinel-2 Based Dataset
Get PDFKhaya senegalensis is an emerging option for climate change mitigating strategies, however, quantifying the carbon sequestration potential of Khaya in Sri Lankan conditions remains a critical concern. Tree-level biomass models exist for Khaya, they lack in spatial representation, which is crucial for stand-level carbon stock estimates. This study developed stand-level models to representation of the stand variability, emphasizing the efficiency of remote sensing in capturing spatial features and spatial heterogeneity. Therefore, this study aimed to develop remote sensing[1]based stand scale above-ground biomass (AGB)/above-ground carbon (AGC) prediction models using the relationship between remote sensing-based vegetation indices and estimated AGB/AGC based on the field measurements. The field data were collected from 53 sample plots of Khaya senegalensis monoculture forest plantation located in the intermediate zone, Sri Lanka. The Conditional Latin Hypercube sampling (cLHS) method was used to identify the sample points. The tree biomass and carbon content were derived using a tree-level allometric model available in the literature, collecting substantial field data such as diameter at breast height (DBH), tree height, and stocking density. This tree-level carbon content was scaled up to the plot level, building the relationship between the total AGB of the plot and the plot structural variables (Stand Basal Area[1]BA, Stand Mean height-H, and Stand Density-SD). In this study, AGB was modelled with 7 vegetation indices derived using Sentinel-2 imagery. The Classification and Regression Tree (CART) model was fitted as the final model since AGB, and vegetation indices perform a complex and nonlinear relationship. The k-fold cross-validation method was used to validate the final model. The selected plot scale, field models have higher R2 -adj and lower error statistics. Finally selected plot scale allometric model was AGB=aBAb SDb1+ ε [RSE (4.781), RSS (1143), AIC (321.169), BIC (329.051), RMSE (4.644 Mgha-1 ), MAE (3.342), R2 -adj (0.9)] and remote sensing-based stand scale AGB model was based on the four vegetation indices namely, Normalized Vegetation Index (NDVI), Sentinel-2 Red Edge Position (S2REP), Enhanced Vegetation Index (EVI), and Normalized Difference Index (NDI) 45. Between AGB and vegetation indices were revealed higher variability and a more complex combination. This discloses when modelling AGB/AGC using remote sensing-based indices, tree-based machine learning algorithms are more appropriate than linear regression modelling. However, to generalize this model across Sri Lanka, further testing needs to be done with a large dataset.
Keywords: Khaya senegalensis, Biomass, Remote sensing, Allometric equation, Up-scalin
A Situational Audit on the Agricultural Seed Systems: A Case Study in Imbulpe Divisional Secretariat Division, Sri Lanka
Get PDFA seed system is a network of processes, organisations, and market dynamics contributing to the development, production, dissemination, and regulation of seeds. It is the foundational component for agricultural productivity and biodiversity, influencing crop yields, farmer resilience, and the adaptability of agriculture to changing environmental conditions. Seed systems can be structured and regulated (formal), community and farmer-based (informal), or a combination of these two. This paper explores the components of seed systems in the Imbulpe area of the Ratnapura district, exploring how they interact at local and regional levels to move seeds from breeders to farmers and the impact on agricultural practices. Seeds serve as custodians of preserving genetic diversity and a determinant of future agriculture. However, there are significant challenges that threaten the efficacy and sustainability of seed systems. Our research objectives were to identify the nature of the existing seed system in the Imbulpe area, understand the governance and controls in place, and explore the gaps and opportunities to improve the existing seed system to help preserve genetic diversity. Data was collected through questionnaires facilitated via interviews and focus group discussions with a target of fifty farmers, as well as consultations with local agrarian services institutions in the area. The questions covered existing seed systems and modifications done to improve or correct these systems. The formal seed system in the Imbulpe area involved agrarian services and key seed merchants, such as Hayleys and CIC. Informal seed systems were primarily used by subsistence farmers and those growing vegetables and fruits alongside large paddy fields where seed saving, exchanging, and selling among farmers defined systems used. Formal seed systems offered several qualities in seed which are helpful to farmers in terms of productivity, consistency, and reliability. High germination rates, genetic purity and uniformity, disease and pest resistance, and adaptability and resilience were found to enhance productivity for farmers. These were backed by soft services such as quality assurance and certification of seeds, access to new seed varieties, as well as technical support and guidance where appropriate. It is recommended that additional research work be done to determine the level of governance necessary to support the informal seed system in place, by allowing the seed quality to be assessed before distribution. Local farmers should be helped to devise their own voluntary protocols to ensure that their seeds are disease free and viable by using seed quarantines and test germinations. In conclusion, we found a healthy informal seed system within the Imbulpe area that could be improved with awareness through extension programs.
Keywords: Seed systems, Value chain analysis, Agricultural development, Food security, Resilienc
Lianas are Increasing in the Tropics: A Consolidated Evidence from Southeast India
Get PDFLianas are one of the most conspicuous elements of tropical forest ecosystems, comprising up to 50% of the woody species density and richness. Therefore, they are expected to majorly determine the tropical forest structure, function, and dynamics. Are lianas increasing in dominance in tropical forests has been a focused question in several recent studies. While the studies from neotropical sites agree with this claim, results from Afro-tropical sites have produced a contrasting trend. At this crucial juncture, we present the evidence for increasing liana abundance and biomass in the seasonally dry tropical forest sites of Southeast India based on over 30 years of long-term monitoring from six 1 ha permanent plots. During the initial inventory, all lianas ≥1 cm DBH were enumerated and tagged using serially numbered aluminium metal tags. At decadal intervals, each 1 ha permanent plot was re-invented for liana censusing. The liana density has increased by ~30% from the initial inventory. The results also revealed the decrement of trees by more than 35% during the same censusing interval. Similarly, the liana basal area and biomass increased significantly during the study period. While the underlying ecological mechanisms favouring lianas are still unclear, this crucial evidence from the present study will further strengthen the liana increment hypothesis in the tropics. The ecological implications of increasing liana dominance are also discussed.
Keywords: Forest dynamics, Population density, Long-term monitoring, seasonally dry tropical forests, Above-ground biomas
Effect of Salinity on the Morphological and Physiological Parameters of Quinoa (Chenopodium quinoa Wild.), Amarillo Marangani Variety
No full textQuinoa (Chenopodium quinoa Willd.) is a genetically diversified Andean crop, which has drawn attention from all over the world for its nutritional and health benefits as well as its adaptability to a variety of conditions, including marginal agroecosystems that are stressed by drought and nutrientpoor, salinized soils. Salinity is the main factor that inhibits crop growth at both the cellular and whole plant levels. Where high salinity groundwater is utilized for irrigation, soil salinity poses a significant concern in growth and development of plants. The aim of the present study was to investigate the effects of salinity on morphological and physiological parameters of quinoa variety Amarillo Marangani. Salt stress was imposed by application of 0 mM NaCl, 200 mM NaCl and 300 mM NaCl to the plants grown in pots (12 cm×12 cm). (Five plants per treatment) with 95% of field capacity of water. Tree height and stem diameter as morphological parameters and relative water content (RWC %) and stomatal density as physiological parameters were measured through 34 weeks of treatment period and analysed statistically using Minitab 17. Based on the morphological findings, plants grown under 300 mM NaCl showed the least growth in average height of 56.16±1.42 cm compared with the average heights of plants grown under 200 mM NaCl (62.33±2.85 cm) and 0 mM NaCl (66.50±2.59 cm). The stem dimeter under 300 mM NaCl showed a mean value of 3.40±0.11 mm compared with 200 mM NaCl (3.93±0.07) mm and 0 mM NaCl (4.2±0.07) mm respectively. Plants grown under 300 mM NaCl showed a significantly lower average RWC% value of 71.16±0.42 compared with the mean RWC % of 77.39±0.63 and 87.02±1.03 at 200 mM NaCl and 0 mM NaCl respectively. Comparing the values of stomatal density in different salinity conditions, plants grown under 300 mM NaCl has the lowest average stomatal density 54.64±1.36 than the plants under 200 mM NaCl 62.33±1.13 and 0 mM NaCl 74.20±1.59. The results emphasized that high salt concentrations in soil affected the plant growth morphologically and physiologically but considerable growth at salt concentration of 200 mM in the Amarillo Marangani variety.
Key words: Quinoa, Amarillo Marangani, Salinity, Growth parameter
Floristic Diversity, Composition and Conservation Importance of Flora in the Salgala Forest Reserve in Kegalle District, Sri Lanka
No full textSalgala forest (Ketagilla Mukalana) reserve (SFR) is a small, isolated lowland wet evergreen forest situated in Kegalle district was declared as a government reserve in 1817 due to its rich plant and animal diversity. This FR is under threat of degradation due to different anthropogenic activities. For conservation and protection measures, a prior knowledge on the floristic composition and diversity of the forest is crucial. This study was carried out to assess the species diversity and composition of FR along an elevational gradient (high elevation- above 300 m, mid elevationbetween 250 m-300 m, and low elevation- between 200 m-250 m). The stratified random sampling was carried out due to the heterogeneity of terrain. Therefore 7 plots with the dimensions of 10 m×10 m were used for measuring overstory trees having girth at breast height (GBH), GBH>=30 cm and height>=1.5 m. Total 49 sub-plots (7 sub-plots per one major plot) of sizes 2 m×2 m (4 plots) and two plots of sizes 1 m×1 m were used to assess the diversity of understory vegetation including the herbaceous plant species (GBH<30 cm, height<1.5 m). The Hutcheson's t-test was used to analyse diversity variation in standing vegetation along the three elevations categories. In this study, a total of 51 plant species were identified belonging to 38 families and 47 genera. Out of the species recorded, 28 (55%) were identified as endemic species while 23 (45%) are indigenous. Also, Zeuxine regia and Anoechtochilus regalis, which are nationally vulnerable plants were identified in SFR. Species belonging to family Annonacea were identified dominantly in overstory vegetation while species belonging to Stemonuraceae and Asparagaceae were dominated in understory vegetation. For the standing vegetation, mid elevation has recorded the highest diversity value for Shannon Weiner diversity index (H') (H'=3.5390), while the high elevation has recorded the least diversity value (H'=2.7659). The elevation and slope-related factors including soil erosion, surface water runoff, soil nutrition depletion due to the irregular surfaces with frequent rock outcrops and amount of sunlight received were affected to diversity reduction with increasing elevation. Therefore, differences in plant growth requirements, competitive pressures, human disturbances could be the cause of variance in the vegetation composition that currently exist in these seven sampling sites. Hence, more studies on diversity and composition variations in different landscapes are importance to get the idea of conservation practices in the Salgala FR.
Keywords: Endemic species, Hutcheson’s t-test, Shannon Diversity Index, Slope effec
Impact of Naturally Occurring Water Types and pH on the Emergence and Survival of Aedes albopictus Mosquitoes in Southern Sri Lanka
No full textMosquitoes play a major role in significant disease outbreaks in humans and animals in many parts of the World. A better understanding of mosquito fauna in diverse ecological conditions including physico-chemical parameters is important in risk assessment of vector-borne diseases. Thus, this study was designed to identify the impact of naturally occurring water types and pH on Aedes albopictus, one of the dengue disease vector mosquitoes in Sri Lanka. Five different water types, i.e., marine, brackish, pond, rain, and distilled water; as well as pond water with three different pH values (pH 6, pH 7, and pH 8) were used for this study. Twenty eggs each of Aedes albopictus under different water types and pH levels were used to identify the survival and completion of their life cycle through larvae to the emergence of adult mosquitoes. Control setups were also used together with the experiment setups. pH and salinity of the different water types were also measured for all the water types. During this study, a total of 560 eggs were monitored and four replicates each were used for the analysis under different water types and pH values. Measured pH values were highest in marine water (pH 8.96-9.20), and it was lowest in rainwater (pH 5.05-5.70). Conductivity levels were also highest in marine water (4,880.76-5,530.60 µS/m) and it was lowest in distilled water (0.00–0.02 µS/m). According to the observations, the highest hatching percentage was reported in brackish water (18±1.83) and pond water under pH value 8 (8.25±5.62). Meanwhile, the lowest hatching percentage was reported in pond water with pH 6 (3±3.56). The highest adult emergence was also given in brackish water (17.8±2.2) and pH value 7 (7±00). However, the lowest adult emergence was observed under pH value 6 (2.5±00). Especially, no larvae or adults emerged from marine water. There was a significant difference in larvae hatching and adult emergence in different water types and under-selected pH values 6 (2.5±00) Especially, no larvae or adults emerged from marine water. There was a significant difference in larvae hatching and adult emergence in different water types and under-selected pH values (P< 0.05). The findings of this study are crucial in the recognition of the impact of water types and pH on the emergence and survival of Aedes albopictus mosquitoes in Sri Lanka.
Keywords: Adult emergence, Hatching success, Mosquito survival rate, Physico-chemical parameters, Water qualit