Browsing by Author "Wijethunga, H.N.S."

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    Assessment of Macroalgae Diversity along the Economically Important Southern Coastal Zone of Sri Lanka during North East (NE) Monsoon Period
    (Uva Wellassa University of Sri Lanka, 2020) Wijethunga, H.N.S.; Silva, A.P.R.; Shanuke, D.S.; Abeygunawardana, A.P.; Senevirthna, J.D.M.; Bambaranda, B.V.A.S.M.; Thushari, G.G.N.; Liyanage, N.P.P.
    Southern coastal zone acts as a highly productive ecosystem with rich macroalgae diversity. However, limited scientific studies have been conducted on macroalgae diversity in the southern coastal belt of Sri Lanka. The current study is focused on the assessment of the intertidal, macroalgae diversity along this coastal belt. This study was conducted using systematic sampling technique along the intertidal zone at 12 selected regional coasts (Hambantota, Godawaya, Rekawa, Tangalle, Dickwella, Polhena, Mirissa, Weligama, Unawatuna, Galle Fort, Dodanduwa and Hikkaduwa) representing three districts (Hambantota, Matara, Galle) of the southern province during NE monsoon period (December 2019 to February 2020). NE monsoon period was selected to minimize the climatic effects during sampling in different seasons. Macroalgae species were taxonomically identified using the recommended pictorial guides and literature records. Oneway Analysis of Variance (ANOVA) was employed to identify the variations of macroalgae diversity with sampling location (p<0.05). According to the results, a total of 26 macroalgae species (10 belong to Chlorophyta: >38% richness, 10 in Rhodophyta: >38% richness, and 6 from Phaeophyta: >23 % richness) were identified in this coastal belt. Ecologically dominant species belong to division Chlorophyta out of all the sampling sites. Shannon-Wiener biodiversity index (H') of the macroalgae in respective ecosystems significantly changed with sampling locations (p<0.05). The spatial variation pattern of biodiversity is correlated with unsustainable anthropogenic activities and natural factors. Shannon-Wiener biodiversity index (H') ranged at 0.67-2.59 in the study sites. The highest composition of macroalgal species (20) was recorded from the Godawaya site due to the minimum anthropogenic effect. Mirissa (02) and Dodanduwa (01) regions had the lowest macroalgae species richness and commercial activities were relatively higher along these coastal zones compared to all other sites. Accordingly, macroalgae act as the biological indicators reflecting the health status of respective ecosystems. So, the findings of this study would be important to identify the quality of the coastal zones and apply appropriate coastal conservation and management measures in the future. Also, the commonly recorded macroalgae species which belong to Chlorophyta and Rhodophyta can be sustainably utilized in processing value-added foods and other products. In conclusion, this study reveals the current status of macroalgae diversity on the southern coast during the NE monsoon period and detailed investigation of species composition is strongly recommended throughout the year. Keywords: Biodiversity assessment, North east monsoon, Macroalgae, Intertidal zone, Coastal ecosystems
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    Occurrence of Microplastics in Gut and Muscles of Commerson's Anchovy in Madu-Ganga Estuary of Southern Province, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Praboda, M.W.K.; Egodauyana, K.P.U.T.; Wijethunga, H.N.S.; Abeygunawardana, A.P.; Senevirathna, J.D.M.; Thushari, G.G.N.
    Plastic pollution causes serious ecological risks on biodiversity with toxicological effects on the biota. The objective of this study was to assess microplastic accumulation in seasonally common fishery resource: Stolephorus commersonnii (Commerson's Anchovy) harvested from Madu-ganga estuarine ecosystem. Fifteen matured fish samples (n=15) were randomly collected from local fishermen from November 2019 to January 2020. Microplastic particles were extracted from the digestive tract and muscles of anchovies using the recommended protocol of 10% KOH digestion. Hot needle test and Fourier Transform Infrared Radiation (FTIR) analysis were used for the confirmation of microscopically observed microplastics in anchovy samples. Microscopically observed microplastics were counted and categorized according to the size, color, and shape of plastics. Results revealed the microplastic accumulation in both the digestive tract and muscles of anchovies. Microplastics accumulate into the muscles via translocation and different respiratory modes. The average microplastic accumulation rate of anchovy gut and muscles were recorded as 301.70±3.58 items/g and 29.33±1.19 items/g respectively. White/transparent microplastic particles were the most abundant type in both guts (145.50±2.18 items/g) and muscles (13.55±1.23 items/g) of fish. However, blue (71.33+0.83 items/g: gut, 9.85+1.13 items/g: muscle), black (37.85+1.07 items/g: gut, 2.49+0.44 items/g: muscle), red (28.31+0.60 items/g: gut, 2.31+0.3 items/g: muscle) and pink (15.31+0.34 items/g: gut 0.96+0.24 items/g: muscle) microplastic debris were also recorded from gut and muscle samples. The majority of accumulated plastics in both gut and muscles were at the size range of 0.50 -1.00 mm. Fiber shape microplastics were observed in all the samples. FTIR results revealed that polypropylene as the only polymer type of microplastics in fish muscles and gut. This polymer is a key component of fishing ropes, netting materials, bottle caps, and packaging materials that enter through tourism/recreational activities and fishery operations into the estuarine ecosystem. Therefore, the current study recommends sustainable, integrated fishery management and eco-tourism programs focusing on plastic pollution control and prevention activities in Madu-ganga estuarine ecosystem. In conclusion, this study highlights the occurrence of microplastic contamination in the estuarine biota and the urgent need for plastic wastes management programs. Keywords: Coastal fishery resources, Estuarine ecosystem, Integrated fishery management, Microplastic accumulation rate, Plastic pollution control programmes
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    Phytoplankton Diversity in Six Major Reservoirs of Badulla District, Uva Province, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Eheliyagoda, P.G.R.; Kumarage, N.T.; Abeygunawardana, A.P.; Thushari, G.G.N.; Liyanage, N.P.P.; Chandrasena, G.; Silva, A.P.R; Wijethunga, H.N.S.
    Phytoplanktons are major primary producers and act as a bioindicator in inland waters. The present study investigated the phytoplankton species composition of six reservoirs (Ulhitiya, Rathkinda, Mapakada, Nagadeepa, Dambarawa, and Sorabora) with highest inland fish production in Badulla district. Samples were collected using a plankton net (60 μm mesh size) from five sampling points of each reservoir during November 2019- January 2020. The taxonomical status of collected samples was identified using previous literature records, standard pictorial guides (The Genera of the Freshwater Algae of Sri Lanka). Biodiversity indices were calculated to identify the variations of phytoplankton diversity among sampling points and reservoirs. Total of 41 phytoplankton species belonging nine major taxonomic classes; Bacillariophyceae (10), Chlorophyceae (10), Cyanophyceae (08), Zygnemaphyceae (06), Eugenophyceae (02), Fragilariophyceae (02), Chryotophyceae (01), Xanthophyceae (01), Dinophyceae (01) were recorded. Diatoms (Bascillariophyceae) recorded the highest relative abundance (61.57%) from selected reservoirs. Sampling points of each reservoir had no significant effect (p>0.05) on the phytoplankton diversity while it showed a significant effect (p>0.05) on phytoplankton diversity among reservoirs. The highest Shannon-Wiener index (1.61±0.06), Simpson’s Index (0.71±0.01), evenness (0.52±0.024) and richness (21±1.62) were reported from Dambarawa, while lowest Shannon-wiener index (1.25±0.19), Simpson’s index (0.59±0.08), evenness (0.42±0.19) and richness (19±0.89) resulted for Ulhitiya Reservoir. The current study reveals that Aulacoseira sp, Microcystis sp, Pediastrum sp, Staurastrum sp, Arthrospira sp shows the highest abundance in all six reservoirs. Dominant species play a vital role as primary producers, bioindicators (Aulacoseira sp, Microcystis sp), and feed (Staurastrum sp, Arthrospira sp) for fish. Due to the high abundance of Microsystis sp. (51.58%) in the Ulhitiya reservoir, the potential to generate toxic algal blooms was identified by the current study. In conclusion, this study identified the dynamic phytoplankton community and dominant species which act as the major autotrophs in studied reservoirs. Further, data collected could be used as the baseline information for the aquatic ecological studies and inland fishery enhancement programs Keywords: Shannon-Wiener index, Simpson’s index, Biodiversity, Inland fishery, Primary producers/autotrophs
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    Screening of Plastic Pollution Effects in Madu-ganga Estuarine Ecosystem in Southern Province, Sri Lanka: An Approach toward the Coastal Zone Management
    (Uva Wellassa University of Sri Lanka, 2020) Praboda, M.W.K.; Wijethunga, H.N.S.; Silva, A.P.R.; Gayathry, D. L.; Abeygunawardana, A.P.; Senevirathna, J.D.M.; Thushari, G.G.N.
    Plastic pollutants act as the emerging contaminant with possible threats to aquatic ecosystems. The present study attempts to assess microplastic (MP) content in surface water and sediments of Madu-Ganga estuary which is one of the ecologically and commercially important Ramsar wetlands in Sri Lanka. Manta net (380 μm) was employed to collect surface water samples by towing net horizontally along water surface for 10 m with 1.8 ms-1 of average flow rate, while Ekman grab was used for sampling sediments from 4 study sites during October 2019 to January 2020. Wet Peroxide Oxidation (WPO) protocol was applied after subjecting both water and sediment samples to the wet sieving process. Fourier Transform Infrared Radiation (FTIR) analysis was used to confirm polymer types of extracted MPs in samples. MPs in digested samples were enumerated and categorized microscopically according to their size, shape, and color. One Way Analysis of Variance (ANOVA) was applied to identify the differences of MPs density with sampling location (p<0.05). According to the results, both surface water and sediment layers had contaminated by MPs accumulation. Sampling location had not significant (p>0.05) effect on the MP content of surface water and sediment samples. Average MPs accumulation rate of surface water and sediment samples were recorded as 40.06±1.84 items/m3 and 5.88±1.33 items/100g respectively. Whitetransparent, blue, black, and red were major color categories observed in MPs, while white-transparent color was dominant MP type of water and sediment samples. Most of the accumulated MPs were at the 0.50-1.00 mm of long-range. Fiber, sheet, and fragment shape MPs were commonly found in water and sediment samples. According to FTIR analysis, polypropylene (Characteristic absorption bands: 2950 cm−1 , 2915 cm− 1 , 2838 cm− 1 , 1455 cm− 1 , 1377 cm− 1 ) was abundant polymer type in surface water, while sediment contains polypropylene and polyvinyl chloride (Characteristic absorption bands: 1427 cm−1 , 1331 cm−1 , 1255 cm−1 ,1099 cm−1 , 966 cm−1 ). As per the preliminary survey, two major anthropogenic activities: commercial fishery and tourism were identified as the main point and non-point pollution sources in this ecosystem. In conclusion, this study emphasizes the growing risk of plastic pollution and the urgent need for a sustainable management plan to reduce plastic pollution in the Madu-Ganga estuary ecosystem. Keywords: Plastic contamination, Microplastics, Coastal ecosystem, Surface water, Benthic sediments, Anthropogenic factors
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    Screening the Effects of Microplastics on Selected Invertebrates along Southern Coastal Belt in Sri Lanka: A Preliminary Approach to Coastal Pollution Control
    (Uva Wellassa University of Sri Lanka, 2019-02) Wijethunga, H.N.S.; Athawuda, A.M.G.A.D; Dias, P.C.B; Abeygunawardana, A.P.; Senevirathna, J.D.M.; Thushari, G.G.N.; Liyanage, N.P.P.; Jayamanne, S.C.
    Primary and secondary microplastics entering into coastal and marine environment are potentially harmful to the health of aquatic organisms. Current study intended to assess plastic pollution effects on sessile invertebrates along the Southern coastal belt of Sri Lanka during July-December 2018. Twelve sampling sites (Hambantota, Godawaya, Rekawa, Tangalle, Dickwella, Polhena, Mirissa, Weligama, Unawatuna, Gallefort, Dodanduwa and Hikkaduwa) with different anthropogenic activities were selected as representing 03 districts (Hambantota, Matara, Galle) of Southern province. Biodiversity survey was conducted to identify prevalence of natural inhabitants in selected regional coasts and 03 dominant coastal mollusks: Saccostrea cucullata (Rock Oyster), Littorina sp. (Periwinkle) and Patella sp. (Limpets) were selected for screening microplastics accumulation level. Alkaline digestion protocol was identified as the most suitable procedure for microplastics extraction considering plastics recovery rate and digestion efficiency of flesh. Randomly collected, pooled biological samples (N=20-2) were subjected to KOH digestion and resultant microplastics were verified using hot needle test. As results revealed, all 03 invertebrates were contaminated with microplastics accumulation at average rates of 7.2-2.8counts/g in all sampling sites. Majority of contaminated microplastics were filamentous types (>90%) followed by rod shapes (1%). Microplastic accumulation rate varied significantly according to the type of species (p<0.05) due to differences of their feeding mechanism. Further, filter feeding organisms (Rock Oysters) were highly susceptible in accumulation of microplastics (7.24.1counts/g) in their bodies, while plastic accumulation rate was highest in oysters from Hambantota. Microplastic accumulation rate of mollusks was not significantly different according to the sampling site due to closer proximity (p>0.05). Tourism, unsustainable coastal fishery and harbor operational activities were identified as key factors affecting on higher plastic pollution level on Southern coast. Current study reflects negative aspect of plastic pollution on intertidal organisms.