Accumulation of Trace Metals, Petroleum Hydrocarbons, and Polycyclic Aromatic Hydrocarbons in Marine Copepods from the Arabian Gulf

In this study, zooplankton samples were collected from the coastal waters of Qatar during winter and summer 1998 to assess the impact of growing industrialization on the bioaccumulation of trace metals, total petroleum hydrocarbons (TPHCs) and polycyclic aromatic hydrocarbons (PAHs) in copepods, the dominant zooplankton group and main food for fish in the Arabian Gulf

Extreme 15N Depletion in Seagrasses

Seagrass beds form an important part of the coastal ecosystem in many parts of the world but are very sensitive to anthropogenic nutrient increases. In the last decades, stable isotopes have been used as tracers of anthropogenic nutrient sources and to distinguish these impacts from natural environmental change, as well as in the identification of food sources in isotopic food web reconstruction. Thus, it is important to establish the extent of natural variations on the stable isotope composition of seagrass, validating their ability to act as both tracers�of nutrients and food sources. Around the world, depending on the seagrass species and ecosystem, values of seagrass N normally vary from 0 to 8 ? ?15N. In this study, highly unusual seagrass N isotope values were observed on the east coast of Qatar, with significant spatial variation over a scale of a few metres, and with ?15N values ranging from +2.95 to ?12.39 ? within a single bay during March 2012. This pattern of variation was consistent over a period of a year although there was a seasonal effect on the seagrass ?15N values. Seagrass, water column and sediment nutrient profiles were not correlated with seagrass ?15N values and neither were longer-term indicators of nutrient limitation such as seagrass biomass and height. Sediment ?15N values were correlated with Halodule uninervis ?15N values and this, together with the small spatial scale of variation, suggest that localised sediment processes may be responsible for the extreme isotopic values. Consistent differences in sediment to plant 15N discrimination between seagrass species also suggest that species-specific nutrient uptake mechanisms contribute to the observed ?15N values. This study reports some of the most extreme, negative ?15N values ever noted for seagrass (as low as ?12.4 ?) and some of the most highly spatially variable (values varied over 15.4 ? in a relatively small area of only 655�ha). These results are widely relevant, as they demonstrate the need for adequate spatial and temporal sampling when working with N stable isotopes to identify food sources in food web studies or as tracers of anthropogenic nutrients.Scopu

Geochemical composition of dust from Qatar peninsula

Atmospheric dust samples have been collected from different areas in Qatar and analyzed for major and trace element composition. This region of the Arabian Gulf represents an area largely affected by dust from natural and anthropogenic sources. Twenty one samples were collected during 2014 and 2015 from Al-Khor, Katara, Sealine, Al-Waab, and Qatar University by passive and active sampling techniques. Some bulk samples were collected during the massive megastorm that occurred in April 2015. Back trajectories were determined for each sample set using the NOAA HYSPLIT model over a 50 hour time interval. Samples were equally divided between northerly (n=12; northern Saudi Arabia, Kuwait or Iraq) and southerly (n=8; SE Saudi Arabia, United Arab Emirates and Oman) sources. One sample is expected to originate from westward, in Saudi Arabia. There is more variability noticed in source locations throughout the winter months (October to March), with more of them coming from the south (9 times) compared to summer months (April to September) for twice only. Dust samples were microwave-assisted, total acid digested (HF+HCl+HNO3) and oxidized with H2O2 before analyses were conducted by ICP-OES. Only 12 out of 23 elements (Al, Ca, Fe, K, Mg, Na, Ag, As, Ba, Be, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sr, V, Zn, P) of the Qatari dust samples were enriched relative to Upper Continental Crust (UCC). Calcium was especially enriched to a level of 400% relative to UCC. About 33% of the total sample mass was CaCO3, reflecting the composition of surface rocks in the source areas. Of the elements typically associated with anthropogenic activity, Ag, Ni, and Zn were the most enriched relative to UCC, with enrichment factors of 182%, 233%, and 209%, respectively. Other metals like Pb and V were not significantly enriched, with enrichment factors not exceeding 25% and 3%, respectively. Major elements (Al, Mn and Fe) were depleted relative to UCC due to the strong enrichment of CaCO3, with enrichment factors of -58%, -35% and -5%, respectively. Samples with northern and southern origins were separated to investigate if the elemental composition could be used to identify source/origin. Only three elements were observed to have a statistical difference. Pb and Na were higher in the samples collected from the south while Cr was higher in those from the north. This study aims to investigate present-day geochemistry of dust particles and its effect on the marine environment of the Arabian Gulf. The geochemical composition of dust is essential component for correcting lithogenic input to water column suspended matter samples.qscienc

Present Limits to Heat-Adaptability in Corals and Population-Level Responses to Climate Extremes

Climate change scenarios suggest an increase in tropical ocean temperature by 1–3°C by 2099, potentially killing many coral reefs. But Arabian/Persian Gulf corals already exist in this future thermal environment predicted for most tropical reefs and survived severe bleaching in 2010, one of the hottest years on record. Exposure to 33–35°C was on average twice as long as in non-bleaching years. Gulf corals bleached after exposure to temperatures above 34°C for a total of 8 weeks of which 3 weeks were above 35°C. This is more heat than any other corals can survive, providing an insight into the present limits of holobiont adaptation. We show that average temperatures as well as heat-waves in the Gulf have been increasing, that coral population levels will fluctuate strongly, and reef-building capability will be compromised. This, in combination with ocean acidification and significant local threats posed by rampant coastal development puts even these most heat-adapted corals at risk. WWF considers the Gulf ecoregion as “critically endangered”. We argue here that Gulf corals should be considered for assisted migration to the tropical Indo-Pacific. This would have the double benefit of avoiding local extinction of the world's most heat-adapted holobionts while at the same time introducing their genetic information to populations naïve to such extremes, potentially assisting their survival. Thus, the heat-adaptation acquired by Gulf corals over 6 k, could benefit tropical Indo-Pacific corals who have <100 y until they will experience a similarly harsh climate. Population models suggest that the heat-adapted corals could become dominant on tropical reefs within ∼20 years

Man-made impact on the geochemistry of the Nile delta lakes. A study of metals concentrations in sediments

Forty two sediment samples were collected from four River Nile northern delta lakes (Mariut, Edku, Burullus and Manzalah) to asses the man-made impact on their environment during the last 20 years. Due to the continuous discharge of agricultural, industrial and sewage waste waters to these lakes, significant variations in the sediment's nature took place, with fine fractions dominating opposite to the outflowing area of the main drains. Organic carbon was elevated at the southern regions, reaching 10.5 ± 4.5% in lake Mariut. Meanwhile, carbonate increased reaching 90% for samples collected at the lake-sea connection areas. The 0.5 N HCl extractable metals indicated enriched levels of different metals at sites affected by sewage and industrial discharge. This fraction constituted 75 and 81% of the total metals in Lakes Mariut and Manzalah, respectively. Extractable Cd for Lakes Mariut and Manzalah constituted 51 and 53%, respectively, while Ph formed 59% of the total digestable metal in Lake Manzalah. Total metals concentrations especially Cd and Pb were elevated 8 to 70 times than those observed in the same lakes 25 years ago. The conversion of the untreated sewage discharge of Alexandria city to Lake Mariut and significant portion of Cairo sewage to Lake Manzalah during the past 10 years lead to the appearance of elevated levels of contaminants in both lakes. Agricultural discharge showed less impact on Lakes Edku and Burullus. Cluster analysis revealed associations between stations located under same types of stress while the correspondence factor analysis displayed that metals distribution pattern in the Nile delta lakes are governed by organic carbon as well as fine grained size fraction distribution

Dissolved copper, cadmium and lead in the coastal waters of Qatar, Arabian Gulf

143-149The concentrations of Cu, Pb and Cd have been determined in the exclusive economic zone of Qatar, Arabian Gulf during December 1993. Cathodic stripping voltammetry (CSV) was used both before and after UV destruction of organic matter in filtered samples, to differentiate between the total dissolved as well as the labile fractions. Metals distribution in the area is affected by the circulation pattern. Average total dissolved metals were 30.3 +/- 13.42, 8.53 +/- 4.37 and 0.61 +/- 0.46 nM kg(-1) for Cu, Pb and Cd, respectively. The organic fraction constituted on the average 37 +/- 13 % (Cu), 28 +/- 18 % (Ph) and 26 +/- 12 % (Cd) of the total dissolved metal indicating the affinity of Cu > Ph > Cd to form stable organic complexes. Significant relations appeared between organic Cu with both organic carbon and chlorophyll a. Inorganic Cd/reactive phosphorus ratio (average 1.46+0.73 nM:mu M-1) and inorganic Cu/reactive Si ratio (average 5.9 + 2.4 nM :mu M-1) were three orders of magnitude higher than the global ratios indicating nutrient deficiency in this part of the Gulf

تراكم بعض الفلزات الثقيلة في الأسماك الاقتصادية والروبيان من المياه القطرية

A total of 150 fish and prawn samples representing the most economically important species were collected during 1995-96 by experimental fishing in three locations covering the coastal waters of Qatar. Fish and prawn flesh were analysed for the oil related metals Cr, Pb, Ni and V. The range of levels in fish were 0.06 -0.64 |Xg g"1, 0.03 - 0.93 (ig g"1, 0.31 - 2.23 |Xg g"1 and ND - 0.232 |ig g"1 for Cr, Pb, Ni and V, respectively;تم عن طريق الصيد التجريبي جمع 150 عينة من الأسماك الاقتصادية والروبيان خلال عامي 1995/ 1996, من ثلاثة مواقع تغطي المياه القطرية ( السافلية - رأس لفان ومسيعيد ) وتحليل محتواها من فلزات الكروم ، الرصاص ، النيكل والفانديوم . أوضحت النتائج ارتفاع طفيف في تركيز تلك الفلزات في الروبيان عنها في الاسماك خاصة في المواقع المتأثرة بالصرف الصناعي . أظهرت الاسماك القاعية قدرة مرتفعة على مراكمة الفلزات عن الأنواع البلاحية، بينما كانت معظم القيم التي تم الحصول عليها مقاربة لتلك المسجلة سابقا في المياه القطرية والخليج العربي . ارتفعت قيم الرصاص في بعض العينات لتقترب من الحد المسموح به دولياً لتناول المأكولات البحرية . رغم التحقق من أن معدل الاستهلاك الحالي للاسماك والروبيان في قطر لايزال أمن لمستهلكي المأكولات البحرية فان وضع برنامج رصد دائم لمتابعة تركيزات الفلزات في تلك الكائنات أصبح ضرورة

الطحالب البحرية ككاشفات حيوية لمستويات التلوث في الخليج العربي

The extensive distribution of several marine macroalgal species makes them a potential bioindicator tool for monitoring existing levels of different types of marine pollutants in the region. The present work illustrates the importance of a few widely distributed species of marine algae in depicting the levels of some toxic heavy metals and hydrocarbons along the Qatari and Saudi Arabian shores. Results indicate a strong bioaccumulation potential in these species for both heavy metals and hydrocarbons. A similar monitoring scheme using these identified species could very well be extended to other areas in the Gulf in order to form a comprehensive monitoring plan for the region. This field study also highlights the potential for removal of pollutants by algae as they are washed ashore in large quantities in the region.التوزيع المكثف لعدد من الطحالب البحرية في الخليج يلعب درراً كبيراً في استخدامها ككاشفات حيوية لرصد، تركيزات بعض الملوثات في المنطقة . وتوضح الدراسة الحالية أهمية تواجد وانتشار بعض أجناس الطحالب في تقدير مستويات بعض الفلزات الثقيلة والهيدروكرلونات البترولية حول السواحل القطرية والسعودية . أبرزت النتائج تراكم تلك الملوثات في هذه الأجناس بصورة واضحة وكذلك امكانية تطبيق برنامج رصد مكثف مشابه في أماكن أخرى بمنطقة الخليج . كما ألقت الدراسة الضوء على أهمية التخلص الطبيعي من الملوثات البحرية عند انجراف الطحالب بعد موتها بكميات كبيرة على شواطىء المنطقة

التركيب البيوكيميائي للكوبيبودا يوتربينا اكيوتفرانز في المياه الساحلية للأسكندرية

Protein, carbohydrate and lipid contents were determined in the most numerous and wide spread copepod Euterpina acutifrons collected from the coastal waters of Alexandria. Protein is the major biochemical component of the copepod constituting on the average 35.2 ± 6.7% of the organisms' dry weight followed by carbohydrate (7.9 ± 1.6%) and lipid (3.7 ± 1.9%) contents. Organisms collected from the Eastern Harbor (eutrophic basin) affected by sewage discharge were characterized by high biochemical contents while opposite to landbased sources affected by industrial discharge, the organisms' biochemical components were at a minimum. Compared to other representatives of the zooplankton community, Euterpina retains high protein content indicating its suitability as food for marine fishes. The step wise multiple regression equations revealed that the different biochemical components of Euterpina are mostly affected with the occurrence of available food represented by chlorophyll a concentrations. The average Protein/Carbohydrate ratio for E. acutifrons i.e. 4.46 ± 2.3 indicate that the organism is inhabiting a nutrient sufficient environment. Lipid/protein ratios more than 0.2 observed at industrial discharge affected areas indicate pollution impact on protein production.تم تعيين المحتوى البيوكيميائي لكائن يوتريبنا اكيوتفرانز ، اكثر الكوبيبودات عددا وانتشارا في المياه الساحلية لمدينة الاسكندرية. كان البروتين هو المكون البيوكيميائي الرئيسي حيث كون 25,2% من الوزن الجاف للكائن تلاه الكربوهيدرات (9 , 7%) ثم الدهون (3,7%) . أظهرت الكائنات المجموعة من الميناء الشرقي للإسكندرية المعرض للتلوث بمخلفات الصرف الصحي أعلى قيم للمركبات البيو كيميائية في حين سجلت أقل قيم في المناطق المعرضة للصرف الصناعي . مقارنة بمثيلاتها من العوالق الحيوانية . أظهرت يوتربينا أعلى مستويات للبروتين مؤكدة فائدتها كغذاء للأسماك البحرية . أوضحت الدراسات الإحصائية تأثر المحتوى البيوكيميائي للكائن تأثرا كبيراً بتوفر الغذاء الممثل في الكلوروفيل أ. كما أثبتت النسبة المرتفعة للبروتين / كربوهيدرات أن الكائن يعيش في بيئة غنية بالأملاح المغنية ، في حين أن نسبة الدهون / البروتين التي تتجاو 2، و التي تم تسجيلها في المناطق المتأثرة بالصرف الصناعي تدل على تا اثير التلوث على زيادة إنتاجية البروتينات