1,720,956 research outputs found
Plankton Assemblage in Coastal Waters near to Kalu Ganga River Mouth, Sri Lanka
No full textThe plankton community plays a major role in the stability of coastal ecosystems. They serve as key players in marine food webs. The current study was conducted to investigate the plankton diversity in coastal waters near Kalu Ganga river mouth, Sri Lanka. Six sampling locations were selected based on the random sampling technique, including three locations (CR1-CR3) along the right-side coastline and three locations (CL1-CL3) along the left-side coastline from the river mouth. Zooplankton and phytoplankton at each location were sampled from September 2020 to February 2021 using a 55 µm plankton net in surface waters on a monthly basis. Zooplankton and phytoplankton were morphologically identified to the nearest possible taxonomic level by using standard keys and guides. Shannon-Weiner diversity index (H) was calculated to determine the plankton diversity. Number of phytoplankton species found in the wet months (September-October) and dry months (JanuaryFebruary) were 62 and 68 respectively, while a similar number of zooplankton species (43) were recorded in both periods. Altogether, 81 phytoplankton species and 53 zooplankton species were identified during the research period. Bacillariophyta (72%) and Copepods (68%) were identified as the dominant phytoplankton and zooplankton groups respectively. Dinoflagellates including, Peridinium sp., Protoperidinium sp., Ceratium sp., Noctiluca sp., Gonyaulax sp., Alexandrium sp., which are well-known to form harmful algal blooms (HABs) accounted for 17%. Chlorophyta and Cyanophyta were less dominated and found only during wet months at nearest sampling locations (CL1 and CR1) to river mouth. Among them Closterium sp. was the dominant. Rotifera (11%), foraminifera (9%), protozoa (10%) and ichthyoplanktons (<1%) were also reported. The H values for plankton were recorded between 2.7 to 3.1 and values were not significantly different (p>0.05) between wet months and dry months at each location. The highest H value (3.1) was reported at the nearest sampling locations (CL1 and CR1) to the river mouth from each side of the coastline. Nauplius and Nitzchia sp. were the most abundant zooplankton and phytoplankton respectively in the study area. Although the number of recorded plankton species was almost similar in both periods, a variation of species composition was observed between wet months and dry months. The plankton diversity as well as the number of reported freshwater phytoplankton were increased towards the river mouth along the coastline. Further research should be conducted to determine the temporal and spatial variation of plankton diversity in the studied area.
Keywords: Kalu Ganga river mouth, Coastal waters, Plankton diversity, Shannon-Wiener diversity inde
Assessment of Water Quality of an Urban Wetland: Bellanvila-Attidiya, Colombo, Sri Lanka
No full textThe rapidly urbanizing land-use pattern in Colombo has limited the role of wetlands to sink various pollutants. It has affected their crucial ecological functions. The present study was conducted to assess the surface water quality in the Bellanvilla-Attidiya wetland using twelve key water parameters to examine the suitability of wetland waters for aquatic life. Based on the random sampling technique, ten locations were selected from the wetland area. Surface water samples were collected from January-April (dry months) and September-December (wet months) of 2023. Pollution status and the suitability of the wetland water for aquatic life were assessed using the water pollution index (WPI). Temperature, pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), salinity, and dissolved oxygen (DO) were measured onsite using portable meters. In the laboratory, nitrate-N, ammonia-N, orthophosphate, total phosphate, chemical oxygen demand (COD), and chlorophyll-a (Chl-a) were analyzed using standard analytical methods. Monthly average rainfall data for the study period were procured from the Department of Meteorology, Sri Lanka, corresponding to the meteorological station nearest to the study site. Results were compared with ambient water quality standards for aquatic life in Sri Lanka. COD and DO were not within the standard levels among the tested parameters. Although surface water contamination is possible due to increased surface runoff during the wet months, pearson-correlation results revealed that the monthly average rainfall has significant negative correlations (p<0.05) with concentrations of nitrate-N (r2=-0.880), ammonia-N (r2=-0.802), and COD, (r2=-0.483) which can be attributed to dilution impacts. The WPI was reported as 2.1±0.23 and 1.2±0.1, respectively, during dry and wet months. Therefore, the wetland area can be categorized as highly polluted (WPI>1- highly polluted) and unsuitable for aquatic life. There was a significant difference in WPI between wet months and dry months (P<0.05). Further, the monthly average rainfall of the study area has a strong negative correlation (p<0.05, r2=-0.800) with WPI values suggesting increased pollution levels in water during dry months. It is recommended that immediate intervention measures, such as reducing urban runoff and controlling pollutant discharge, be implemented to mitigate further degradation of water quality and protect the ecological integrity of this vital urban wetland ecosystem.
Keywords: Bellanvila-Attidiya wetland, Water pollution index, Aquatic life, Wet months, Dry month
Assessment of Plankton Diversity in Madunagala Hot Water Springs, Sri Lanka
No full textHot water springs present unique ecological niches due to their elevated temperatures and distinctive chemical compositions. This study aimed to investigate the plankton diversity of Madunagala hot water springs, one of the major hot springs in the Hambantota district, Sri Lanka. Plankton samples were collected using a 55µm standard plankton net from the surface waters of three interconnected wells (n=6) during July and August of 2023. In addition to that, temperature, pH, electrical conductivity (EC), Total Dissolved Solids (TDS), salinity, and Dissolved Oxygen (DO) were measured using portable meters at the site itself. Standard methods were used to determine the Total hardness (TH), nitrate (N-NO3-), and orthophosphate concentrations at the laboratory. Plankton were morphologically identified to the nearest possible taxonomic level. There were 15 phytoplankton taxa and 22 zooplankton taxa which were identified at least to the genus level, and some of the observed plankton species remained unidentified. Identified phytoplankton belonged to cyanophyta, bacillariophyta, euglenophyta, and chlorophyta; chlorophyta was the dominant phytoplankton group. Pediastrum spp. was identified as the most diverse one, reporting three species, including P. simplex, P. duplex, and P. tetras. Copepoda, rotifera, and microcrustaceans were reported as zooplankton groups. The average zooplankton density (40×104 individuals/m3) was higher than the average phytoplankton density (29×104 individuals/m3). The calculated Shannon-Wiener Diversity index value (H) and Simpson’s index of Diversity (SID) values ranged from 2.6 to 3.1 and 0.6 to 0.8, respectively, indicating moderate to high diversity levels of plankton in Madunagala hot water springs. H and SID values were not significantly different among the wells (p>0.05). The average value for temperature was 43.2±1.2 OC while pH, EC, TDS, Salinity, and DO were reported as 7.98±0.11, 5.13±1.10 mS/cm, 2.57±1.23 ppt, 3.1±0.2 ppt, 2.13±1.12 mg/L respectively. TH was reported as 982±24 mg/L as CaCO3. The N-NO3- and orthophosphate were reported as 0.8±0.1 mg/L and 0.2±0.1 mg/L respectively. There were no significant differences in any parameter among the wells (p>0.05). The plankton species that have been identified can be considered temperature tolerance species, which are found in water above 42º
These plankton might have specialized adaptations to high-temperature conditions, including heat resistance, metabolic versatility, etc.
Keywords: Madunagala hot water springs, Plankton diversity, Temperature tolerance species, Shannon-Wiener Diversity Index, Simpson’s index of diversit
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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