Distribution and environmental geochemical indices of mercury in tar contaminated beaches along the coast of Qatar

The current study aimed to gauge total mercury (THg) concentration and the environmental geochemical indices in tarmat contaminated sediments and test their presence in targeted coastal species. Layers of hard asphalt-like tarmats and sediment samples were collected from 34 sites along the coast of Qatar. The mean concentration of THg in tarmat-sediment mixture is 89 ± 20 ng·g−1. THg concentration varies significantly between the northern and eastern coasts. Geographically, sampling area were divided into four zones according to the relative closeness with low to serious potential ecological risk index (Er), moderate pollution load index (PLI), moderate Geoaccumulation index (Igeo), and no toxic risk (TRI) trending as Northern (Zones 4, 3) > North-Eastern (Zone 1) > Western (Zone 2) coasts. Three biota classes (Gastropoda, Bivalvia, and Crustacea) were sampled on the tarmat which the hermit crab (Clibanarius signatus) from Ras Rakan island obtained the highest THg (977 ng·g−1) and BSAF (29.70)

Spatial variability of summer hydrography in the central Arabian Gulf

The Arabian Gulf is a very significant ocean body, which hosts more than 55% of the oil reserves of the world and produces about 30% of the total production, and thus, it is likely to face high risk and adverse problems by the intensified environmental stressors and severe climatic changes. Therefore, understanding the hydrography of the Gulf is very essential to identify various marine environmental issues and subsequently, developing marine protection and management plans. In this study, hydrography data collected at 11 stations along 3 linear transects in the early summer of 2016 were analyzed. The physicochemical parameters exhibited apparent variations along each transect, both laterally and vertically, connected to stratification, formation of different water masses and excessive heating. The temperature and salinity decreased laterally from nearshore to offshore, while layered density structures were identified in the offshore regions. The pH, dissolved oxygen (DO) and chlorophyll fluorescence (Fo) exhibited distinct horizontal and vertical variations. The observed pH is within the normal ranges, indicating that seawater acidification may not be a threat. The highest DO (6.13–8.37 mg/l) was observed in a layer of 24-36 m water depth in the deeper regions of the central transect

Monitoring oil spill in Norilsk, Russia using satellite data.

This paper studies the oil spill, which occurred in the Norilsk and Taimyr region of Russia due to the collapse of the fuel tank at the power station on May 29, 2020. We monitored the snow, ice, water, vegetation and wetland of the region using data from the Multi-Spectral Instruments (MSI) of Sentinel-2 satellite. We analyzed the spectral band absorptions of Sentinel-2 data acquired before, during and after the incident, developed true and false-color composites (FCC), decorrelated spectral bands and used the indices, i.e. Snow Water Index (SWI), Normalized Difference Water Index (NDWI) and Normalized Difference Vegetation Index (NDVI). The results of decorrelated spectral bands 3, 8, and 11 of Sentinel-2 well confirmed the results of SWI, NDWI, NDVI, and FCC images showing the intensive snow and ice melt between May 21 and 31, 2020. We used Sentinel-2 results, field photographs, analysis of the 1980-2020 daily air temperature and precipitation data, permafrost observations and modeling to explore the hypothesis that either the long-term dynamics of the frozen ground, changing climate and environmental factors, or abnormal weather conditions may have caused or contributed to the collapse of the oil tank.Open access funding provided by the Qatar National Library

Observed variability in physical and biogeochemical parameters in the central Arabian Gulf

In situ measurements of physical and biogeochemical variables were conducted along a transect in the Exclusive Economic Zone (EEZ) of Qatar during late summer (September 2014) and winter (January 2015) to investigate their vertical, spatial and temporal variability. The study reveals that the water column is characterized by strong stratification during late summer in the deepest station, where the water depth is around 65 m and the surface to bottom temperature variation is around 9.1°C. The water column is vertically homogeneous during winter due to surface cooling and wind mixing. The surface to 23 m water column is characterized by ample dissolved oxygen (DO) during late summer and winter in the offshore regions, however, relatively low DO is found during late summer due to weak mixing and advection under weak winds and currents. Dissolved oxygen drops to hypoxic levels below the summer thermocline, and the winter high DO layer extends up to the bottom. Chlorophyll-a (Chl-a) is relatively high during late summer in the offshore region, while that in the nearshore regions is very low, which is linked to the anthropogenic stresses from the central east coast of Qatar. The results identified in this study fill an essential gap in the knowledge of regional primary production dynamics.Environmental Science Center (ESC) & Department of Biological and Environmental Sciences (DBES), Qatar University (QU

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

Target gastropods for standardizing the monitoring of tar mat contamination in the Arabian Gulf

This study proposes a standardization process for the monitoring the level of tar mat contamination in the Arabian Gulf. In the study, we selected target gastropod species and evaluated the ecological and ecotoxicological effects of tar mats on their populations, the bioaccumulation of heavy metals, and these species’ potential as bioindicator taxa for tar mat-associated heavy metals. The study was carried out at two sites on the Qatar coast on shoreline rocks, both of which have areas of tar mat coverage and areas without tar mats. The species selected as representative species for the ecoregion were the endemic Clypeomorus bifasciata persica (Houbrick, 1985) in the intertidal zone and the Echinolittorina arabica (El Assal, 1990) in the supratidal zone. Both are grazers and are niche restricted to hard substrates and daily scraping/grazing on the tar mat deposition zone of the shorelines. The key heavy metal indicators chosen were As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn, and the gastropod species were divided into classes according to their size. Tar mat presence was found to negatively affect both the overall population size of Clypeomorus and different size classes, and lead to high levels of assimilation of heavy metals. Tar mat presence also negatively affected different size classes of Echinolittorina where large sizes were found to be most significantly affected. The results also demonstrated that Cu and Ni are the heavy metals most associated with tar mat contamination of this kind. Overall, our results confirmed that grazer gastropods are good bioindicators of tar mat-associated contaminants in shoreline ecosystems. Our study provides the database on the heavy metal contamination of the proposed target gastropods, and offers information that will be relevant for further monitoring and comparisons among threatened coastal areas in the Arabian Gulf.This research was supported by the Qatar Petroleum through the project of QU (QUEX-ESC-QP-TM-18/19)

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

COVID-19 personal protection equipment (PPE): A potential source of microplastic pollution in the State of Qatar

Coronavirus disease 2019 (COVID-19) has become a global pandemic. The personal protection equipment (PPE), especially medical face masks and N95 filtering face piece respirators (FFRs) are typically worn by people at home/office/working place/outside to protect from infection. Thus, the increase in consumption of face masks and FFRs across Qatar has given rise to a new environmental challenge, adding to the vast plastic waste in the environment. Our team has already established the baseline levels of marine litter (ML) including plastic waste along the west coast of Qatar based on November 2019 ML survey (Veerasingam et al., 2020a). To study the impact of COVID-19 on ML, we have conducted another survey along the west coast of Qatar in July 2020. The distribution of PPE is higher on the southern part of west coast of Qatar than the northern part. Attenuated Total Reflectance - Fourier Transform Infrared (ATR-FTIR) Spectroscopy was used to characterize the polymer types of surgical face masks, N95 FFRs and gloves. Polypropylene (PP) and Polyamide (PA) were the abundant polymer types of PPEs. This study confirmed that the PPE could be a potential source for microplastic contaminant in the environment, especially if the present situation continues. Therefore, proper waste removal measures have to be followe

Surface waves generated by shamal and easterly winds off Qatar

Waves in the Arabian Gulf are primarily controlled by the regional winds, for example, shamal winds during winter and early summer. Though Gulf wave characteristics have been heavily utilized for the design of offshore platforms and structures, wave features associated with various wind systems are not explicitly covered scientifically, say, for the Exclusive Economic Zone (EEZ) of Qatar. Therefore, we made an attempt to identify the features associated with different wind systems by analyzing the measured waves off Fuwairit, north coast of Qatar during 29 Oct - 26 Nov 2019. The analyses have been further extended to the Gulf using the reanalysis waves obtained from the COPERNICUS Marine Environment Monitoring Services (CMEMS) to describe the monthly, seasonal and annual characteristics. The results indicate that the easterly waves generated due to Nashi winds influence the east and northeast coasts of Qatar and shamal waves show clear dominance in the northern and northeastern offshore boundaries of the EEZ of Qatar. We find exceptional easterly (Nashi) waves during March 2019 contributing to the highest monthly mean significant wave height, which is a deviation from the known long-term wave climate of the Gulf

A multiscale ocean modelling system for the central Arabian/Persian Gulf: From regional to structure scale circulation patterns

The Arabian/Persian Gulf (hereafter, the “Gulf”) is one the busiest and fastest changing sea in the World. Its circulation is primarily driven by the surface water inflow from the Sea of Oman and density-driven and wind-driven flows within the Gulf. The regional circulation in its central part, particularly around Qatar, could not be explored because of unavailability of measured current data and the coarse resolution opted for the entire Gulf modelling. In the present study, we developed a high-resolution ocean modelling system of the entire Gulf with a particular focus on Qatar coastal waters. The model uses an unstructured mesh with different resolutions ranging from ∼5 km in the open ocean to ∼150 m along the coast of Qatar and less than 40 m around artificial structures. The model results have been validated with in situ data collected off Qatar. It allows seamless simulations of hydrodynamic processes from the entire basin scale down to the scale of coastal structures. The study identifies seasonal variability in currents and eddies in the central part of the Gulf. It also suggests the existence of four prominent anticyclonic eddies in the Gulf of Salwa, south of Bahrain. At the structure scale, the flow is mostly tidally driven and can be intensified beyond 1 m/s through narrow passages such as between breakwaters or within artificial waterways. By explicitly representing the effect of ocean sprawl on the coastal circulation, our model has the potential to greatly improve the environmental impact assessment of coastal developments in the Gulf area.We are grateful to Dr. Antoine Saint-Amand and Ms. Lauranne Alaerts for their help in producing some of the figures. We further thank Prof. Hamad Al-Saad Al-Kuwari, Director, Environmental Science Center (ESC), Qatar University (QU) for his constant encouragement and support. This work was jointly carried out by QU and UCLouvain under the QU Collaborative Grant project (QUCG-ESC-22/23-591), funded by QU, Qatar. Computational resources were provided by the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the F.R.S.-FNRS, Belgium under Grant No. 2.5020.11