Natural and anthropogenic sources of extractable organic matter in sediments from the coastal zone of the Arabian Gulf in Saudi Arabia

2021 ◽  
Author(s):  
Ahmed I. Rushdi ◽  
Aarif H. El-Mubarak ◽  
Bernd R. T. Simoneit ◽  
Miguel A. Goni ◽  
Mohammed A. Qurban ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Organic Matter ◽  
Higher Plants ◽  
Gulf Coast ◽  
Arabian Gulf ◽  
Complex Mixture ◽  
Anthropogenic Sources ◽  
Gas Chromatography Mass Spectrometry ◽  
Terrestrial Vegetation ◽  
Extractable Organic Matter

Abstract Surface sediment samples from the Arabian Gulf coast of Saudi Arabia were collected by Van Veen grab sampler to identify the characteristics, distribution, levels, and to discriminate between natural and anthropogenic sources of the total extractable organic matter (TEOM). The dried and sieved sediments were extracted with a dichloromethane/methanol mixture for analysis by gas chromatography-mass spectrometry. The TEOM included n-alkanes (353.9±283.8 ng.g−1), n-alkanols (283.2±296.1 ng.g−1), fatty acid methyl esters (245.2±353.7 ng.g−1), hopanes (100.7±158.2 ng.g−1), steranes (58.5±96.3 ng.g−1), triterpenoids (18.9±21.1 ng.g−1), steroids (15.3±17.0 ng.g−1), polycyclic aromatic hydrocarbons (PAHs) (0.48±1.19 ng.g−1), as well as an unresolved complex mixture (UCM =1633±3151 ng.g−1) and petrochemicals (343.1±424.2 ng.g−1). The major sources of these TEOM compound groups were anthropogenic (petroleum and petrochemical) and natural (lipids from higher plants, marine material, and microbiota) inputs. Anthropogenic contaminants from petroleum products ranged from 46.6-85.6% of the TEOM, whereas petrochemicals varied from 10.7-40.6%. Biogenic influx from terrestrial vegetation ranged from 5.7-19.3%, and marine biotic sources varied from 11.1-37.5%. The continuous accumulation of anthropogenic contaminants will ultimately affect the critical habitats of this marine coastal region. This provides a basis for further studies to understand human and developmental activities on delivery, deposition processes, distribution, and biogeochemical alteration of organic matter in the coastal zones of the Arabian Gulf. Such studies are important for sustainable development and protection of these key regional habitats.

Monitoring metal levels in water and multiple biomarkers in the grouper (Epinephelus tauvina) to assess environmental stressors on the Arabian Gulf coast of Saudi Arabia

2018 ◽  
Vol 34 (5) ◽  
pp. 301-314
Author(s):  
Ashraf M Abdel-Moneim ◽  
Mohamed A Al-Kahtani ◽  
Omar M Elmenshawy ◽  
Hany Elsawy ◽  
Aly M Hafez ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Gulf Coast ◽  
Arabian Gulf ◽  
Environmental Stressors ◽  
Eastern Coast ◽  
Activity Levels ◽  
Hepatocellular Necrosis ◽  
Metal Levels ◽  
Multiple Biomarkers ◽  
Gill Lamellae

In this field study, the levels of heavy metals (Pb, Fe, Co, Cu, and Zn) in water and a suite of biochemical and histological biomarkers in the grouper ( Epinephelus tauvina) were assessed at four sites in the Arabian Gulf. Samples were taken from a relatively non-urban reference site, called Salwa (S1), and three effluent-dominated sites, namely Al-aziziyah in southern Dammam city (S2), the Al-Jubail coast (S3), and Manifa (S4). Toxic metals, namely Pb and Co (at all sites) and Fe (at S3), were elevated in water samples relative to the internationally permissible limits. In fish, induced levels of heat shock protein 70 (HSP70) in the liver at S3 and S4 were higher than those of the reference fish at S1. Additionally, the level of the lipid peroxidation (LPO) product (malondialdehyde (MDA)) was significantly increased in gills (at S3) and liver (at S2 and S3). There was an inhibition of catalase activities in the gills of fish from S2 to S4 and significantly higher activity levels of superoxide dismutase in the gills of fish from S4. Histopathological features such as aneurysms in gill vessels, deformed gill lamellae, increases in liver melano-macrophage centers, and hepatocellular necrosis were most abundant at sites where significant pollution problems exist (i.e. S2–S4). The results reveal that the eastern coast of Saudi Arabia, in the Arabian Gulf, is still contaminated, as indicated by elevated HSP70, LPO content and numbers of histological lesions, and that monitoring of contaminants and their effects should be continued in this region.

scholarly journals Molecular, Radioactive and Stable Carbon Isotope Characterization of Estuarine Particulate Organic Matter

Radiocarbon ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 985-990 ◽  
Author(s):  
Luc Megens ◽  
Johannes Van Der Plicht ◽  
Jan W. De Leeuw
Keyword(s):  
Organic Matter ◽  
Carbon Isotope ◽  
Suspended Matter ◽  
Stable Carbon Isotope ◽  
Complex Mixture ◽  
Total Carbon ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
C Value ◽  
Final Residue

Organic matter in sediments and suspended matter is a complex mixture of constituents with different histories, sources and stabilities. To study these components in a suspended matter sample from the Ems-Dollard Estuary, we used combined molecular analysis with pyrolysis/gas chromatography/mass spectrometry and stable and radioactive carbon isotope analyses of the bulk and separated chemical fractions. Carbohydrates and proteins, ca. 50% of the total organic carbon (TOC), are much younger than the bulk sample and have a somewhat higher δ13C value. Lipids and the final residue are considerably older and have lower δ13C values. The final residue, ca. 17% of the total carbon, consists mainly of aliphatic macromolecules that could be derived from algae or terrestrial plants. The δ13C value points to a marine origin.

scholarly journals Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

2014 ◽  
Vol 11 (5) ◽  
pp. 538 ◽  
Author(s):  
Athanasios Rizoulis ◽  
Wafa M. Al Lawati ◽  
Richard D. Pancost ◽  
David A. Polya ◽  
Bart E. van Dongen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Critical Role ◽  
Stable Isotope Probing ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Organic Substrates ◽  
Spectrometry Analysis ◽  
Subsurface Sediments ◽  
Extractable Organic Matter ◽  
Long Chain

Environmental context The use of groundwater with elevated concentrations of arsenic for drinking, cooking or irrigation has resulted in the worst mass poisoning in human history. This study shows that organic compounds that can be found in arsenic rich subsurface sediments may be used by indigenous microorganisms, contributing to the release of arsenic from the sediments into the groundwater. This study increases our understanding of the range of organic substrates (and their sources) that can potentially stimulate arsenic mobilisation into groundwaters. Abstract Microbial activity is generally accepted to play a critical role, with the aid of suitable organic carbon substrates, in the mobilisation of arsenic from sediments into shallow reducing groundwaters. The nature of the organic matter in natural aquifers driving the reduction of AsV to AsIII is of particular importance but is poorly understood. In this study, sediments from an arsenic rich aquifer in Cambodia were amended with two 13C-labelled organic substrates. 13C-hexadecane was used as a model for potentially bioavailable long chain n-alkanes and a 13C-kerogen analogue as a proxy for non-extractable organic matter. During anaerobic incubation for 8 weeks, significant FeIII reduction and AsIII mobilisation were observed in the biotic microcosms only, suggesting that these processes were microbially driven. Microcosms amended with 13C-hexadecane exhibited a similar extent of FeIII reduction to the non-amended microcosms, but marginally higher AsIII release. Moreover, gas chromatography–mass spectrometry analysis showed that 65% of the added 13C-hexadecane was degraded during the 8-week incubation. The degradation of 13C-hexadecane was microbially driven, as confirmed by DNA stable isotope probing (DNA-SIP). Amendment with 13C-kerogen did not enhance FeIII reduction or AsIII mobilisation, and microbial degradation of kerogen could not be confirmed conclusively by DNA-SIP fractionation or 13C incorporation in the phospholipid fatty acids. These data are, therefore, consistent with the utilisation of long chain n-alkanes (but not kerogen) as electron donors for anaerobic processes, potentially including FeIII and AsV reduction in the subsurface.

scholarly journals Macromolecular composition of terrestrial and marine organic matter in sediments across the East Siberian Arctic Shelf

2016 ◽  
Vol 10 (5) ◽  
pp. 2485-2500 ◽  
Author(s):  
Robert B. Sparkes ◽  
Ayça Doğrul Selver ◽  
Örjan Gustafsson ◽  
Igor P. Semiletov ◽  
Negar Haghipour ◽  
...  
Keyword(s):  
Organic Matter ◽  
Coastal Erosion ◽  
Principal Component ◽  
Arctic Shelf ◽  
The Arctic ◽  
Gas Chromatography Mass Spectrometry ◽  
Terrestrial Organic Matter ◽  
Pyrolysis Gas ◽  
Siberian Arctic ◽  
Extractable Organic Matter

Abstract. Mobilisation of terrestrial organic carbon (terrOC) from permafrost environments in eastern Siberia has the potential to deliver significant amounts of carbon to the Arctic Ocean, via both fluvial and coastal erosion. Eroded terrOC can be degraded during offshore transport or deposited across the wide East Siberian Arctic Shelf (ESAS). Most studies of terrOC on the ESAS have concentrated on solvent-extractable organic matter, but this represents only a small proportion of the total terrOC load. In this study we have used pyrolysis–gas chromatography–mass spectrometry (py-GCMS) to study all major groups of macromolecular components of the terrOC; this is the first time that this technique has been applied to the ESAS. This has shown that there is a strong offshore trend from terrestrial phenols, aromatics and cyclopentenones to marine pyridines. There is good agreement between proportion phenols measured using py-GCMS and independent quantification of lignin phenol concentrations (r2 = 0.67, p < 0.01, n = 24). Furfurals, thought to represent carbohydrates, show no offshore trend and are likely found in both marine and terrestrial organic matter. We have also collected new radiocarbon data for bulk OC (14COC) which, when coupled with previous measurements, allows us to produce the most comprehensive 14COC map of the ESAS to date. Combining the 14COC and py-GCMS data suggests that the aromatics group of compounds is likely sourced from old, aged terrOC, in contrast to the phenols group, which is likely sourced from modern woody material. We propose that an index of the relative proportions of phenols and pyridines can be used as a novel terrestrial vs. marine proxy measurement for macromolecular organic matter. Principal component analysis found that various terrestrial vs. marine proxies show different patterns across the ESAS, and it shows that multiple river–ocean transects of surface sediments transition from river-dominated to coastal-erosion-dominated to marine-dominated signatures.

Sign in / Sign up

Export Citation Format

Share Document