During the 2011 exploration season of the EV Nautilus in the Mediterranean Sea, we conducted a multidisciplinary study, aimed at exploring the microbial populations below the sediment-water interface (SWI) in the hydrocarbon-rich environments of the Levantine basin. Two c. 1000-m-deep locations were sampled: sediments fueled by methane seepage at the toe of the Palmachim disturbance and a patch of euxinic sediment with high sulfide and methane content offshore Acre, enriched by hydrocarbon from an unknown source. We describe the composition of the microbial population in the top 5 cm of the sediment with 1 cm resolution, accompanied by measurements of methane and sulfate concentrations, and the isotopic composition of this methane and sulfate (δ¹³C(CH₄), δ¹⁸O(SO₄), and δ³⁴S(SO₄)). Our geochemical and microbiological results indicate the presence of the anaerobic methane oxidation (AOM) coupled to bacterial sulfate reduction (BSR). We show that complex methane and sulfur metabolizing microbial populations are present in both locations, although their community structure and metabolic preferences differ due to potential variation in the hydrocarbon source.
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http://dx.doi.org/10.1111/1574-6941.12264 | DOI Listing |
Sci Rep
November 2024
Univ. Grenoble Alpes, CNRS, Grenoble INP, LEGI, 38000, Grenoble, France.
The most prominent and persistent feature of the eastern Mediterranean Levantine Basin (LB) is the warm anticyclonic Cyprus Eddy (CE) located above the Eratosthenes Seamount (ESM). This eddy periodically couples with two smaller cyclonic and anticyclonic eddies, the South Shikmona Eddy (SSE) and North Shikmona Eddy (NSE), which form downstream. The reason for the zonal drift of the CE center and the formation mechanism of the CE, SSE and NSE is largely debated today, yet the upwelling and biological productivity of the LB can be strongly impacted by the local dynamics.
View Article and Find Full Text PDFBiol Trace Elem Res
July 2024
Faculty of Fisheries, Mersin University, Mersin, Turkey.
The determination of metal(loid) (As, Fe, Al, Sr, Zn, Pb, Mn, Cu, Cr, and Cd) levels in the muscle tissue of 23 different deep-sea bony fish sampled off Mersin Bay (NE Levantine Basin) and the assessment of health risks for human consumption were aimed. Tissue metal(loid) concentrations were determined as dry weight and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The tissue metal(loid) concentrations (µg g dw) were converted to wet weight prior to health risk assessment calculations.
View Article and Find Full Text PDFEcol Evol
March 2024
Israel Oceanographic and Limnological Research Ltd. Haifa Israel.
The <3% dissimilar Amplicon Sequence Variant (ASV) clusters of the 18S-V4 barcode were used as species-proxies for the evaluation of ASV composition and ASV diversity indices characterizing the hitherto poorly investigated meiofaunal communities of the south-eastern part of the Levantine basin. Accompanied by abundance measurements, the relationships of these characteristics with sedimentary and bottom terrain parameters were interpreted. The construction of community composition profiles, namely ASVs' list and their estimated abundances, was done using our previously established procedure (Harbuzov et al.
View Article and Find Full Text PDFSci Total Environ
April 2024
Israel Oceanographic & Limnological Research, National Institute of Oceanography, Haifa, Israel.
Silica plays a key role in the growth of silicifying primary producers (e.g., diatoms) and hence the ocean carbon pump.
View Article and Find Full Text PDFSci Total Environ
March 2024
Hellenic Centre for Marine Research, Institute of Oceanography, 46.7 Km Athens-Sounio av., Mavro Lithari, 19013 Anavyssos, Attiki, Greece.
Herein, we study the occurrence and water column distribution trends of suspended particle-associated aliphatic (AHCs) and polycyclic aromatic hydrocarbons (PAHs) collected from 36 offshore/deep sea locations across the open northeastern Mediterranean Sea. Total concentrations of the determined compounds fall within the range previously reported for non-polluted coastal and open sea locations worldwide. Mixed natural and anthropogenic sources were evident for the studied compounds, based on their molecular profile and several diagnostic indices.
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