33 research outputs found
Exploring Sheraoh Island at South-Eastern Qatar: First Distributional Records of Some Inland and Offshore Biota with Annotated Checklist
Sheraoh island is the most remote among Qatari islands, nearly 73.5 km south-eastern of the mainland of the
peninsula. In March 2010, a preliminary general survey of the species was conducted. Observations were made partly
by wading and snorkeling in the intertidal zone and partly by surveying the inland habitats. In total the 31 species
were recorded, 4 species of halophyte plants: Halopeplis perfoliata, Suaeda vermiculata, Salsola baryosoma and
Zygophyllum qatarense, one unexpected terrestrial mammal: the cape hare Lepus capensis, 2 species of visiting
birds: Motacilla flava and Anthus campestus and one species of sea bird.
Phalacrocorax nigrogularis, one dolphin species: Sousa chinensis. The largest richness was found in the marine
habitats, 3 species of sea weeds: Colpomenia sinusa, Padina boergesenii and Sargassum boveanum, 3 species of
corals: Anomastraea irregularis, Platygyra lamellina and Porites harrisoni, 2 species of nudibranchs: Chromodoris
cazae and Chromodoris sp. (unidentified)., 4 crab species: Hermit crab (unidentified), Etisus laevimanus, Grapsus
albolineatus and Lambrus prensor, 4 species of echinoderms: Pentacentral mammillatus, Ophiothela venusta,
Diadema setosum and Echinometra mathaei, 5 species of bony fish: Doryrhamphus sp. (larva), Cypserulus
oligolepis, Lethrinus nebulosus, Cephalopholis miniatus and Hemiramphus marginatus, one species of sea snakes:
Hydrophis sp. The most striking result is to collect an unknown nudibranch species and to report the cape hare which
is unexpected inhabitant. All figures of this study are published for the first time in Qatar.Qatar Universit
Molluscan diversity influenced by mangrove habitat in the khors of Qatar
The Exclusive Economic Zone (EEZ) of Qatar is a rapidly developing region within the Arabian Gulf, where monitoring of changes in benthic biodiversity and its functioning is needed. The influence of mangroves and seasonality on the nearshore subtidal molluscan diversity at three distinct khors (nearshore tidal bays) – natural mangroves (Al Dhakhira), planted mangroves (Al Mafyar) and no-mangroves (Dawhat Zekreet) – are investigated in this study. This study concludes that even the sub-tidal area is influenced by mangroves, and mangroves increase the diversity of molluscs compared to the site that lacks mangroves. The maximum salinity (59.8 psu) was observed at Dawhat Zekreet during summer, and the minimum (41.44 psu) at Al Dhakhira in winter. Chlorophyll a level was low for all the khors, and rarely exceeded 1 μg/L, depicting oligotrophic waters. Al Dhakhira demonstrated the highest molluscan species richness (32), and shared 28 species in common with Al Mafyar. Dawhat Zekreet had the fewest mollusc species number and no mangroves. When cumulative diversity over all seasons was considered, Dawhat Zekreet exhibited the lowest species richness; Al Dhakhira, the highest. Some mangrove regions have been already utilized for developmental activities, and Qatar needs to continue the program of mangrove conservation as a vital habitat for molluscs.Open access funding provided by the Qatar National Library. Part of this work has been supported by the QU-NIO joint IRCC project (No. IRCC-2019-002)
Sources, spatial distribution and characteristics of marine litter along the west coast of Qatar
The spatial distribution, sources and characteristics of marine litter (ML) from 36 locations spread over 12 beaches along the west coast of Qatar have been assessed. A total of 2376 ML items with varying sizes were found with an average abundance of 1.98 items/m2. The order of abundance of ML along the coast was as follows: plastics (71.4%) > metal (9.3%) > glass (5.1%) > paper (4.4%) > fabric (4.0%) > rubber (3.9%) > processed wood (2.0%). Locations in the south and northwest coasts of Qatar had significantly higher concentrations of ML. Surprisingly, nearly 47% of the beached polyethylene terephthalate (PET) bottles were derived from the countries bordering the Arabian/Persian Gulf (Gulf), and most of them were produced in the last 2 years. The plastic materials were drifted by winds and currents to the Qatar coast. Gulf circulation provides evidence to the pathways of ML beached on the Qatar coast.We acknowledge ORS, QU for awarding the Project (QUEX-ESC-QP-TM-18/19), funded by the Qatar Petroleum
Spatial distribution, structural characterization and weathering of tarmats along the west coast of Qatar
Oil pollution resulting from natural and anthropogenic activities in the Arabian Gulf as well as oil residue in the form of tarmat (TM) deposited on the coast is a major environmental concern. The spatial distribution, chemical composition and weathering pattern of tarmat along the west coast of Qatar has been assessed based on the TM samples collected from 12 coastal regions. The range of TM distribution is 0–104 g m−1 with an average value of 9.25 g m−1. Though the current TM level is thirty-fold lesser than that was found during 1993–1997 (average 290 g m−1), the distribution pattern is similar. The results of ATR-FTIR spectroscopy indicate that aromatic compounds are higher in the north (N) coast TMs than those found in the northwest (NW) and southwest (SW) coasts, and Carbonyl Index values indicate that TM of NW coast is highly weathered compared to those found in the N and SW coasts.ORS, QU Project (QUEX-ESC-QP-TM-18/19), funded by the Qatar Petroleum
Sentinel-2 image transformation methods for mapping oil spill – A case study with Wakashio oil spill in the Indian Ocean, off Mauritius
Although several indices have been constructed and available at the Index database (IDB) for Sentinel-2 satellite to map and study several earth resources, no indices have been developed to map oil spill. We constructed band ratios (5 + 6)/7, (3 + 4)/2, (11+12)/8 and 3/2, (3 + 4)/2, (6 + 7)/5 using the high-resolution MSI (multi-spectral instrument) visible-near infrared-shortwave infrared spectral bands of Sentinel-2 by summing-up the bands representing the shoulders of absorption features as numerator and the band located nearest to the absorption feature as denominator to discriminate oil spill, and demonstrate the potential of this method to map the Wakashio oil spill which occurred in the Indian Ocean, off Mauritius. The resulted images discriminated the oil spill well. We also decorrelated the spectral bands 4, 3 and 2 by studying the spectral band absorptions and discriminated the spill as very thick, thick and thin. The results of decorrelation stretch method exhibited the distribution of types of oil spill in a different tone, distinctly. Both the image transformation methods (band ratios and decorrelation stretch methods) showed their capability to map oil spills, and these methods are recommended to use for similar spectral bands of other sensors to map oil spills. • This study demonstrated the application of band ratios and decorrelation stretch methods to map oil spill. • The methods discriminated the oil spill off Mauritius, and showed spill thicknesses from the Sentinel-2 data. • The new methods are recommended to use for the spectral bands of other sensors to map oil spill.This work was supported by the Qatar University’s International Research Collaboration Co-Funds project (IRCC-2019-002). The authors are thankful to the Copernicus, European Space Agency for sharing the Sentinel-2 data through the Sentinel open access hub. The authors are thankful to Dr. Damià Barceló, the Editor in Chief and anonymous reviewers of the journal for their valuable reviews and constructive comments that have helped to present the work lucidly. The authors are thankful to Dr. Damià Barceló, Editor in Chief and anonymous reviewers of the journal for their valuable reviews, providing comments and suggestions that have helped to present the work lucidly. Open access funding provided by the Qatar National Library
Effects of bottom substratum on survival and growth of early juveniles of blue swimming crab, (Linnaeus, 1758) in captivity
Aim: Cannibalism remains a limiting factor during the nursery culture of crabs. This study was undertaken to improve the rearing techniques by investigating the impact of bottom substratum on crablet survival and growth. The knowledge gained from the research will be useful for the communal seed culture and development of crab farming, which are important factors regarding farmers' job stability in the future. Methodology: Blue swimming crab, Portunus pelagicus (first settled (C1 crabs); initial average weight and SD of 0.02 ± 0.01g) were cultured in glass aquarium (90 x 44 x 34 cm) and their survival and growth were assessed after 22 days of culture in four types of substratum such as control (none), sand, soil, or sand + soil. All treatments had 25 juvenile crabs, each of which was triplicated. Feeding was done twice a day (9 am and 5 pm) to apparent satiation. Results: Survival of early juvenile crabs cultured with sand was substantially higher at 65.33 ± 6.11% than those cultured with soil, sand + soil or control at 29.33 ± 10.07%, 28.00 ± 8.00%, and 21.33 ± 6.11%, respectively. Growth performance (such as final weight, weight gain and specific growth rate) of the early juvenile of P. pelagicus in all treatments were not significantly different (p>0.05). Interpretation: Overall, the best survival was achieved with sand substratum and can be recommended as a mean of reducing cannibalism during the early nursery rearing of blue swimming crab juveniles under captive culture conditions
Detection of Wakashio oil spill off Mauritius using Sentinel-1 and 2 data: Capability of sensors, image transformation methods and mapping
Oil spill incidents contaminate water bodies, and damage the coastal and marine environment including coral reefs and mangroves, and therefore, monitoring the oil spills is highly important. This study discriminates the Wakashio oil spill, which occurred off Mauritius, located in the Indian Ocean on August 06, 2020 using the Sentinel-1 and 2 data acquired before, during and after the spill to understand the spreading of the spill and assess its impact on the coastal environment. The interpretation of VV polarization images of Synthetic-Aperture Radar (SAR) C-band (5.404 GHz) of Sentinel-1 acquired between July 5 and September 3, 2020 showed the occurrence and distribution of oil spill as dark warped patches. The images of band ratios (5 + 6)/7, (3 + 4)/2, (11 + 12)/8 and 3/2, (3 + 4)/2, (6 + 7)/5 of the Sentinel-2 data detected the oil spill. The images of decorrelated spectral bands 4, 3 and 2 distinguished the very thick, thick and thin oil spills in a different tone and showed clearly their distribution over the lagoon and offshore, and the accumulation of spilled oil on the coral reefs and along the coast. The distribution of post-oil spill along the coast was interpreted using the images acquired after 21 August 2020. The accuracy of oil spill mapping was assessed by classifying the SAR-C data and decorrelated images of the MultiSpectral Instrument (MSI) data using the Parallelepiped supervised algorithm and confusion matrix. The results showed that the overall accuracy is on an average 91.72 and 98.77%, and Kappa coefficient 0.84 and 0.96, respectively. The satellite-derived results were validated with field studies. The MSI results showed the occurrence and spread of oil spill having different thicknesses, and supported the results of SAR. This study demonstrated the capability of Sentinel sensors and the potential of image processing methods to detect, monitor and assess oil spill impact on environment.This work was supported by the Qatar University’s International Research Collaboration Co-Funds project (IRCC-2019-002
Sex ratio,gonad development and fecundity of Miyakella nepa(Crustacea, Stomatopoda) of Pantai Remis coastal waters of Malaysia
The sex ratio, gonad development and fecundity of Miyakella nepa (Latreille, 1828), in the coastal waters of Pantai Remis, Perak, were investigated from February 2012 to January 2013. Sex identification was done by identifying stomatopod's genitalia organs, and the ovaries were dissected out and preserved for further analysis. Female stomatopods with mature or near spawning stages were used for fecundity estimation. A total of 951 specimens of M. nepa, with 565 females and 386 males were examined. Results showed a sex ratio of 1:1.46 (male:females). Maximum GSI was estimated to be 5.80, while lowest was 2.95. Sexual maturity for female M. nepa was observed at 100 mm total length. The mean fecundity of M. nepa was 425,657 (± 1,8701) eggs which was observed to increase with increased body length
GALLSTONES IN PATIENTS WITH INHERITED HEMOLYTIC DISEASES
The purpose is to provide an overview on the incidence of gallstone disease in patients with various types of inherited (chronic) hemolytic diseases at risk of cholelithiasis/choledocholithiasis with particular emphasis on its pathogenesis, genetic, risk factors and management. A detailed electronic literature search to determine the source of materials for this review article was done. The reported incidences of gallstones and choledocholithiasis vary according to the different types of inherited hemolytic diseases and the ethnicity of the studied populations. To date, no review article summarises the incidences of cholelithiasis in patients with various inherited haemolytic diseases was published. Regular ultrasound examination for the presence of gallstones recommended in patients with inherited haemolytic anaemias, particularly those with additional risk factors recommended. Further studies for evaluating the reasons for the higher incidence of cholelithiasis in thalassemia major and sickle cell anemia compared to hereditary spherocytosis; the effect of co inheritance of alpha thalassaemia on decreasing bilirubin level in patients with sickle cell disease and beta thalassaemia; the effect of the co inheritance of UGT1A1 and ABCG8 gene mutation on the incidence of gallstones in other blood diseases such as Hb-H disease, autoimmune haemolytic anaemias, congenital dyserythropoietic anaemia, hereditary elliptocytosis, Southeast Asian Ovalocytosis, glucose-6-phosphate and pyruvate kinase deficiency are recommended. Evaluation of the potential role of the solubility of the mutant proteins and haemoglobin subunit in the red blood cells as an additional mechanism for the development of gallstones in patients with inherited haemolytic anaemias recommended
Climate variability and its impact on the spatial distribution of mangroves in Qatar
Mangroves are a unique vegetation community that can adapt to harsh climatic conditions, including in areas of high temperature and high salinity levels. It is an important coastal wetland community in many countries that provide a multitude of ecosystem services. Qatar has a small mangrove community covering about 21 km2 and it is probably the only natural vegetation type found in Qatar. They are important because of their aesthetic value, as a buffer zone protecting the lowland coastal area as well as its role in storing carbons. Therefore, it is important to understand mangroves response to global climatic variability. This is particularly important as Avicennia, which is the only mangrove species found in Qatar has limited elevation range and less able to resist extreme physical and environmental changes. Species distribution models combined with GIS and Remote Sensing are some of the tools that can be used to project the potential change of mangrove vegetation communities. These spatial information technologies can be used to extract and map current distribution of mangrove vegetation while species distribution model can be used to predict the potential geographical distribution of suitable habitats and species occurrence. In the current research, MaxEnt, GIS and high resolution World View 3 satellite data were used to classify, map and predict mangrove vegetation. The preliminary findings show the potential habitats in the east and the northwest part of Qatar. This research is important as there are no current studies examining the spatial distribution of mangroves or assessing the potential impact of climate variability on mangrove communities in Qatar.qscienc