scholarly journals Influence of environmental factors on the life cycle and morphology of Artemia salina (Crustacea: Anostraca) in Sabkhet El Adhibet (SE Tunisia)

2011 ◽  
Vol 48 (1) ◽  
pp. 67-83 ◽  
Author(s):  
Hachem Naceur ◽  
Amel Jenhani ◽  
Mohamed Romdhane
Keyword(s):  
Population Structure ◽  
Life Cycle ◽  
Environmental Factors ◽  
Dissolved Oxygen ◽  
Physicochemical Parameters ◽  
Morphological Characteristics ◽  
Principal Component ◽  
Artemia Salina ◽  
Maximal Diameter ◽  
The Impact

Influence of environmental factors on the life cycle and morphology ofArtemia salina(Crustacea: Anostraca) in Sabkhet El Adhibet (SE Tunisia)This study was aimed to examine in greater detail the influence of selected environmental factors on the life cycle and morphological characteristics of the brine shrimpArtemia salina(Linnaeus, 1758). During this follow-up, from November 2005 to April 2006 and from November 2006 to April 2007, Sabkhet El Adhibet (southeast Tunisia: 33°07'7.58"N, 11°24'8.69"E) was surveyed monthly to determine the impact of water salinity, temperature, pH, dissolved oxygen, and phytoplankton density and community structure onArtemiadensity, population structure, reproductive mode, and total offspring. Strong correlations were found between physicochemical parameters of water andArtemiareproduction characteristics. In contrast, no significant relationship was detected between physicochemical variables andArtemiapopulation structure and density. Further, there were no correlations between phytoplankton density and theArtemialife cycle. Moreover, we observed relationships between physicochemical parameters and all morphological characteristics, especially between the width of 3rdabdominal segment and salinity (rxy= 0.96), temperature (rxy= 0.73), pH (rxy= -0.77) and oxygen (rxy= -0.92) for male specimens, and between the length of the furca and both salinity (rxy= -0.76) and dissolved oxygen (rxy= 0.74), and between the maximal diameter of compound eyes and temperature (rxy= -0.56) for female specimens. Principal component analysis (PCA) shows that male and female specimens collected at different environmental conditions converge, which explains the morphological similarity between them according to salinity, temperature, and dissolved oxygen concentration as well as total phytoplankton, diatom, cryptophyte, and dinophyte density.

scholarly journals The impact of anthropogenic and environmental factors on the variability of Escherichia coli in rivers in southwest Bangladesh

2021 ◽  
Author(s):  
M. M. Majedul Islam ◽  
Md. Atikul Islam
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Surface Water ◽  
Environmental Factors ◽  
Physicochemical Parameters ◽  
Sewage Treatment Plant ◽  
Oxygen Demand ◽  
Faecal Contamination ◽  
E Coli ◽  
The Impact

Abstract Faecal contamination of surface water sources is an important water quality issue worldwide. Although quite a few studies exist on surface water faecal contamination and variability of indicator bacteria, most of the studies have been based on larger river basins and in temperate region. The variability is relatively unknown in local scale and in tropical developing countries. In this study we assess how anthropogenic and environmental factors affect faecal contamination and physicochemical parameters in Rupsha and Bhairab rivers around Khulna city, Bangladesh. Water samples were collected from six locations of the rivers during a wet and dry period in 2018 to measure Escherichia coli (E. coli) concentrations. Water physicochemical parameters—temperature, turbidity, pH, dissolved oxygen, biochemical oxygen demand and chemical oxygen demand were also measured. Higher concentrations of E. coli were found in the sampling sites located near the densely populated urban area compared to the downstream site, which receives fewer amounts of discharges from sewer drains. All the E. coli samples violated bathing water quality standards. E. coli concentrations were found to be correlated positively with precipitation and turbidity. A linear regression model was applied, that explains large part of the variation in E. coli concentration (R2 = 0.42). Water quality index assessment was also ranked the water quality as ‘poor’ category; indicate that the water is unsuitable for uses in domestic and recreational purposes and high health risks involved with the water use. The study findings highlight the problem of untreated sewage discharge into the rivers. Implementation of sewage treatment plant with adequate capacity is highly recommended.

scholarly journals Isolation-By-Distance-and-Time in a stepping-stone model

2015 ◽  
Author(s):  
Nicolas Duforet-Frebourg ◽  
Montgomery Slatkin
Keyword(s):  
Principal Component Analysis ◽  
Population Genetics ◽  
Population Structure ◽  
Isolation By Distance ◽  
Principal Component ◽  
Joint Effect ◽  
Stepping Stone ◽  
Ancient Times ◽  
The Impact ◽  
Stepping Stone Model

With the great advances in ancient DNA extraction, population genetics data are now made of geographically separated individuals from both present and ancient times. However, population genetics theory about the joint effect of space and time has not been thoroughly studied. Based on the classical stepping--stone model, we develop the theory of Isolation by Distance and Time. We derive the correlation of allele frequencies between demes in the case where ancient samples are present in the data, and investigate the impact of edge effects with forward-in-time simulations. We also derive results about coalescent times in circular/toroidal models. As one of the most common way to investigate population structure is to apply principal component analysis, we evaluate the impact of this theory on plots of principal components. Our results demonstrate that time between samples is a non-negligible factor that requires new attention in population genetics.

In situ study of adult Artemia salina morphometry and its relationship to the physicochemical water parameters in the saltwork of Sahline (Tunisia)

2011 ◽  
Vol 40 (4) ◽  
Author(s):  
Hachem Naceur ◽  
Amel Jenhani ◽  
Mohamed Romdhane
Keyword(s):  
Dissolved Oxygen ◽  
Abdominal Segment ◽  
Principal Component ◽  
Field Work ◽  
Environmental Water ◽  
Artemia Salina ◽  
Morphometric Parameters ◽  
Morphometric Characters ◽  
Water Parameters ◽  
Total Length

AbstractThe morphometric characteristics of the adult natural population of the brine shrimp Artemia salina from the saltwork of Sahline were surveyed in order to establish the relationship between morphometry and environmental water parameters. The field work was performed monthly from October 2005 to June 2006. During this period, the variation in water temperature, salinity, pH, and concentrations of dissolved oxygen and nutrients (orthophosphate, nitrite, nitrate and ammonium) were monitored. Adult Artemia samples (male and female) were randomly collected and stored in plastic containers and transferred to the laboratory for morphometric characterisation. Results show that adult specimens appear in the saltwork of Sahline from December through June. The population sampled in June had significantly lower values in all morphometric characters when compared to the other samples. Concerning male specimens, correlation analysis of the morphometric parameters and environmental conditions indicate that the strongest correlations were between temperature and total length (r xy = −0.656), salinity and total length (r xy = −0.558), and between pH and width of head (r xy = 0.559). For female specimens, the strongest correlations were between total length and salinity (r xy = −0.610), total length and temperature (r xy = −0.537) and between total length and pH (r xy = 0.583). No correlations were observed between dissolved oxygen concentrations or ammonium levels and any morphometric parameters. The principal component analysis (PCA) revealed that diameter of compound eyes, width of second abdominal segment and width of third abdominal segment, for male specimens, and total length, abdominal length and width of the ovisac, for female specimens, are the morphometric parameters that show the greatest variation between samples.

scholarly journals Water hydrochemistry of Lake Boudaroua in the Moroccan Prerifwest Mediterranean region

2021 ◽  
Vol 234 ◽  
pp. 00078
Author(s):  
Hicham En-nkhili ◽  
Issam Etebaai ◽  
Khadija El kharrim ◽  
Driss Belghyti
Keyword(s):  
Surface Water ◽  
Dissolved Oxygen ◽  
Physicochemical Parameters ◽  
Quality Parameters ◽  
World Health ◽  
Total Hardness ◽  
Rate Variation ◽  
Health Organization ◽  
The Impact

In order to assess the quality of surface water of Boudaroua Lake, located in the Moroccan Pre-rif.The water quality parameters was used to evaluate the potential presence of toxicity of this ecosystem. To this end, samples and hydrochemical analyzes were carried out for five permanent stations around the Lake, during the study period (July 2019, October 2019, January 2020). The study was based on 11 parameters, namely, turbidity (TUR), dissolved oxygen (O2), total hardness (DT), calcium (Ca2+),magnesium(Mg2+), sodium (Na+),potassium (K+), ammonium (NH+4), chloride(Cl−), sulfate( SO2−4), nitrate (NO-3)were considered. The results obtained of these physicochemical parameters have been compared with the Moroccan standard (MS) for surface water and with the World Health Organization (WHO). The results indicated that the values of the physicochemical parameters varies significantly seasonally due to precipitation rate variation. In addition the impact of Agricultural pollution resulting from the excessive use of fertilizers that enter the lake through waterways, such as ammonium NH+4, and dissolved oxygen (O2) its value reaching respectively 1.09 mg/L ,12 mg/L remains above standards (MS) and (WHO) which could harm the ecosystem of the lake.

Habitat use of the Japanese eel (Anguilla japonica) and marbled eel (Anguilla marmorata) in the large subtropical Pearl River

2021 ◽  
Vol 57 ◽  
pp. 8
Author(s):  
Fangmin Shuai ◽  
Xinhui Li ◽  
Wanling Yang ◽  
Weitao Chen ◽  
Sovan Lek
Keyword(s):  
Population Structure ◽  
Environmental Factors ◽  
Habitat Use ◽  
Southern China ◽  
Anguilla Japonica ◽  
Japanese Eel ◽  
Pearl River ◽  
Small Scale ◽  
The Pearl River ◽  
The Impact

Anguilla spp. are catadromous fish and with a high economic value in Asia. The Pearl River is the largest river in southern China and is an important area for wild populations of Anguilla spp. However, until now, there has been little research on the eel's population structure and habitat use in the Pearl River. This study analyzed the population structure and habitat use characteristics of the Japanese eel (Anguilla japonica) and the marbled eel (Anguilla marmorata) in the Pearl River based on data collected from 2015 to 2018. A total of 181 Japanese eels and 56 marbled eels were collected, over half of which were middle-sized eels between 255 and 600 mm in length. Although they are sister species, Japanese eels mainly inhabit complex river habitats characterized by high river fractals and coefficients of fluvial facies, while marbled eels mainly inhabit wider and deeper river sections. The impact of physical environmental factors (such as river fractals, coefficients of fluvial facies and river width) on the distribution of these two species is greater than the impact of small-scale water quality environmental factors (such as DO concentration, temperature and clarity). The results of this study showed that wild Anguilla spp. resources in the Pearl River were extremely low and there was an urgent need for conservation and management of eel resources in south China.

The impact of environmental factors on zooplankton communities in the Vistula Lagoon

2011 ◽  
Vol 40 (2) ◽  
Author(s):  
Ewa Paturej ◽  
Marek Kruk
Keyword(s):  
Environmental Factors ◽  
Dissolved Oxygen ◽  
Trophic State ◽  
Vistula Lagoon ◽  
Central Basin ◽  
Total Abundance ◽  
Western Basin ◽  
The Impact ◽  
The Vistula Lagoon ◽  
Oxygen Concentrations

AbstractThe Vistula Lagoon, an estuarine system exposed to both continental and marine impacts, is marked by rapid changes in local environmental conditions, including salinity levels, water transparency, temperature, pH, dissolved oxygen concentrations, trophic state and wind speed. Here, the effect of environmental factors on the abundance and horizontal distribution of zooplankton was analysed. A higher number of taxa were noted in the saltwater intrusion section of the Vistula Lagoon (Central Basin) compared to the area of freshwater inflow (Western Basin). The average density of the analysed zooplankton in the western section of the Vistula Lagoon reached 654 indiv. dm−3, three-fold higher than in the central section (224 indiv. dm−3). Differences in zooplankton biomass were even more pronounced (13.43 mg dm−3 vs. 2.33 mg dm−3). The Central Basin of the Vistula Lagoon was dominated by Copepoda (approx. 50% total abundance), mostly Calanoida (genus Acartia) typically found in brackish waters. Marine species, including Acartia bifilosa and Acartia tonsa, were also reported. Species of freshwater Cladocera predominated in the Western Basin (over 50% total abundance, mostly the eutrophic species Chydorus sphaericus) where Copepoda were represented by a single cyclopoid species, Cyclops vicinus. The saline and freshwater environments of the Vistula Lagoon differed significantly (p<0.001) with respect to the abundance and biomass of zooplankton. The above differences resulted not only from salinity and temperature conditions, but also from dissolved oxygen concentrations, the trophic state of the investigated water body, and the existing biocenotic relationships.

scholarly journals ISSR markers and morphometry determine genetic diversity and population structure in Hedera helix L.

2021 ◽  
Author(s):  
Abdul Shakoor ◽  
Gul Zaib ◽  
Fang Zhao ◽  
Wuyang Li ◽  
Xincan Lan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Similarity ◽  
Diversity Index ◽  
Morphological Characteristics ◽  
Principal Component ◽  
Mantel Test ◽  
Hedera Helix ◽  
Plant Populations ◽  
High Genetic Diversity

Hedera helix L. is an invasive, but medicinally important plant. In Iran, there is no available study on the H. helix population to reveal the genetic diversity and population structure. Fifty-six individual plants belonging to nine geographical populations were collected in four provinces of Iran. High genetic diversity, polymorphisms, and a Shannon diversity index of 0.269 were detected in Mazandaran, Kandovan (Population 3). Analysis of the molecular variance indicated 40% of total genetic variation of the whole population was present in the subpopulation. A high genetic similarity (0.922) between plant Populations 5 (Kermanshah; Islamabad) and 6 (Kermanshah; Paveh) was noted. On the other hand, a low genetic similarity was observed between plant Populations 1 (Tehran; Darband) and 8 (Ardabil; Hur). The Mantel test revealed a correlation between the genetic and geographical distances. Furthermore, it demonstrated the isolation mechanism responsible for the population structure in the H. helix plant populations. The principal component analysis explained the majority of the variation in the morphological characteristics. Three components explained 87% of the variation, and the first component explained 60% of the variation. For instance, the leaf morphology showed a correlation of &gt; 0.7 between leaf morphological and floral characters. The plant leaves and quantitative flower characteristics separated the plant populations according to the differences in length. The current results have implications for plant conservation and management.

scholarly journals The Influence of Polystyrene Microspheres Abundance on Development and Feeding Behavior of Artemia salina (Linnaeus, 1758)

2021 ◽  
Vol 11 (8) ◽  
pp. 3352
Author(s):  
Marco Albano ◽  
Giuseppe Panarello ◽  
Davide Di Paola ◽  
Fabiano Capparucci ◽  
Rosalia Crupi ◽  
...  
Keyword(s):  
Life Cycle ◽  
Feeding Behavior ◽  
Dunaliella Salina ◽  
Food Source ◽  
Developmental Stages ◽  
Artemia Salina ◽  
Dependent Manner ◽  
Polystyrene Microspheres ◽  
The Impact ◽  
Dose Dependent

In the present study, it has been evaluated how 10 µm of polyethylene microspheres can be ingested by Artemia salina (Linnaeus, 1758) larvae within the first 7 days of the life cycle, and the impact on their health. Twelve A. salina larvae (instar I) groups were exposed to different microplastics (MPs) concentrations (0-1-10-102-103-104 MPs/mL), with and without Dunaliella salina as a food source. The results highlighted that A. salina larvae ingest MPs in relation to the exposure times in a dose-dependent manner and are significantly influenced by food availability. The highest contamination found was 306.2 MPs/individual at 104 MPs/mL exposure without a food source. No MPs were found in the presence of the food source from 1 to 102 MPs/mL, while contamination was detected at all concentrations of MPs without a food source. The worst effect on the developmental stages was evaluated at 168 h with a food source, with a delay compared to the control of I and II instars at 103 and 104 MPs/mL, respectively. Furthermore, microalgal feeding was significantly reduced for about 50% in the presence of 104 MPs/mL. These results highlight that aquatic microplastics pollution could affect the A. salina’s feeding behavior and life cycle.

The Impact of Shariah Governance and Corporate Governance on the Risk Management Practices: Evidence from Local and Foreign Islamic Banks in Malaysia

2018 ◽  
Vol 15 (2) ◽  
pp. 1-20
Author(s):  
Sabri Embi ◽  
Zurina Shafii
Keyword(s):  
Risk Management ◽  
Corporate Governance ◽  
Management Practices ◽  
Principal Component ◽  
T Test ◽  
The Body ◽  
Primary Data ◽  
Islamic Banks ◽  
Shariah Governance ◽  
The Impact

The purpose of this study is to examine the impact of Shariah governance and corporate governance (CG) on the risk management practices (RMPs) of local Islamic banks and foreign Islamic banks operating in Malaysia. The Shariah governance comprises the Shariah review (SR) and Shariah audit (SA) variables. The study also evaluates the level of RMPs, CG, SR, and SA between these two type of banks. With the aid of SPSS version 20, the items for RMPs, CG, SR, and SA were subjected to principal component analysis (PCA). From the PCA, one component or factor was extracted each for the CG, SR, and RMPs while another two factors were extracted for the SA. Primary data was collected using a self-administered survey questionnaire. The questionnaire covers four aspects ; CG, SR, SA, and RMPs. The data received from the 300 usable questionnaires were subjected to correlation and regression analyses as well as an independent t-test. The result of correlation analysis shows that all the four variables have large positive correlations with each other indicating a strong and significant relationship between them. From the regression analysis undertaken, CG, SR, and SA together explained 52.3 percent of the RMPs and CG emerged as the most influential variable that impacts the RMPs. The independent t-test carried out shows that there were significant differences in the CG and SA between the local and foreign Islamic banks. However, there were no significant differences between the two types of the bank in relation to SR and RMPs. The study has contributed to the body of knowledge and is beneficial to academicians, industry players, regulators, and other stakeholders.

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