Meiobenthic assemblage of the grey mangrove (Avicennia marina) along the Saudi Arabian coast of the Red Sea with emphasis on free-living nematodes

2018 ◽  
Vol 47 (4) ◽  
pp. 359-375 ◽  
Author(s):  
Abdulmohsin Al-Sofyani ◽  
Mohsen El-Sherbiny

Abstract Spatial variability in the population density of meiofauna and the assemblage of free-living marine nematodes was studied at 20 mangrove sites located along the Saudi Arabian coast of the Red Sea. The total abundance of meiofauna varied between the locations and ranged from 119 to 1380 ind. 10 cm−2. A total of seven main taxa were recorded. Nematodes dominated (64.3%) in all sediment samples. They were followed by harpacticoid copepods (13.2%) and polychaetes (12.9%) with significant differences in their density between the locations surveyed (p < 0.001). The Pearson correlation analysis showed significant positive correlations between the sand fraction and nematodes, harpacticoid copepods and turbellarians. Twenty-five genera of free-living nematodes belonging to 15 families were recorded in the study area. Microlaimidae were the most abundant family, while Xyalidae, Desomodridae and Chromidoridae were the most diverse families. Microlaimus, Halalaimus and Terschellingia were the most frequent genera. ANOSIM values obtained for the distribution of different nematode genera in various habitats showed no significant differences. Feeding types of different nematode genera were also documented and the epistrate feeders along with the deposit feeders were found to be the common feeding types in the present study.

Author(s):  
Rupert Brandmeier

This paper concerns a probable shipwreck cargo of Aqaba amphorae, which was discovered during the second season of the survey project along the Saudi Arabian coast, initiated by nautical archaeologists of Philipps-University Marburg and conducted in cooperation with members of the Saudi Commission for Tourism and Heritage in autumn 2013. Seafaring and sea trade was, according to the few ancient sources and modern research activities, a hazardous endeavor in antiquity. Transport containers like the Aqaba Amphorae played a major role in sea trade, a significant number of which have been detected on various sites along the Red Sea coast and its hinterland. The chronological classification as well as the application is far from complete, and recent archaeometrical investigations help to clarify the logistical aspects of manufacturing and distribution of Aqaba amphorae. Finding a number of remains of Aqaba amphorae at a supposed shipwreck site close to Jeddah delivers new insight into the maritime routes and activities along the western coast of Saudi Arabia. The documentary material currently available is the baseline for further research in the field of maritime archaeology as it pertains to trade in the Red Sea.


2020 ◽  
Vol 18 (1) ◽  
pp. 77-96
Author(s):  
Hameed Alsamadany ◽  
Hassan S. Al-Zahrani ◽  
El-Metwally M. Selim ◽  
Mohsen M. El-Sherbiny

AbstractTo assess trace element concentrations (Zn, Cu, Pb, Cr, Cd and Ni) in the mangrove swamps along the Saudi coast of the Arabian Gulf, thirteen samples of surface sediment and leaves of grey mangrove, Avicennia marina were collected and analyzed. The detected trace element contents (μg g-1) in surface sediments were in the following descending order according to their mean values; Cr (49.18) > Zn (48.48) > Cu (43.06) > Pb (26.61) > Ni (22.88) > Cd (3.21). The results showed that the average concentrations of Cd and Pb exceeded their world average concentration of shale. The geo-accumulation, potential ecological risk and toxicity response indices demonstrated that trace elements have posed a considerable ecological risk, especially Cd. The inter-relationships between physico-chemical characters and trace elements suggests that grained particles of mud represent a noteworthy character in the distribution of trace elements compared to organic materials. Moreover, the results revealed that Zn was clearly bioaccumulated in leaf tissues A. marina. Dredging, landfilling, sewage effluents and oil pollution can be the paramount sources of pollution in the area under investigation.


2018 ◽  
Vol 24 (4) ◽  
pp. 415-423
Author(s):  
Ya Ki Yang

Purpose: This study was done to examine the relationship between participation motivation, satisfaction and continuance willingness of voluntary activities of nursing students, and to identify factors influencing continuance willingness of voluntary activities. Methods: The research participants were 175 nursing students in the nursing departments of 3 universities located in G city and J province in Korea. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficient and multiple regression. Results: Participants' scores for participation motivation, satisfaction and continuance willingness of voluntary activities were $3.24{pm}0.76$, $3.11{pm}0.83$ and $3.03{pm}0.85$ respectively. Participation motivation and satisfaction of voluntary activities had positive correlations. Satisfaction and continuance willingness of voluntary activities had positive correlations. Factors influencing nursing students' continuance willingness of voluntary activities included participation motivation and satisfaction of voluntary activities. And these variables explained 74% of the variance in continuance willingness of voluntary activities. Conclusion: The findings show that development and application of educational programs to increase participation motivation and satisfaction of voluntary activities are important and will improve nursing students' continuance willingness of voluntary activities.


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