Algal and bacterial hydrocarbons in particulate matter and interfacial sediment of the Cariaco Trench

Journal Article · Tue May 01 04:00:00 EDT 1990 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(90)90157-G· OSTI ID:6210733

Wakeham, S G ^[1]

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1. Skidaway Institute of Oceanography, Savannah, GA (USA)

Particulate matter samples and sediment from the sediment-water interface were collected in the Cariaco Trench, an anoxic marine basin on the continental shelf of Venezuela, and analyzed for hydrocarbons. Concentrations of hydrocarbons were highest in oxic surface waters and at the top of the anoxic zone, and were low in the low oxygen zone above the oxic-anoxic interface and anoxic bottom waters. Branched C{sub 25}-trienes and -tetraenes dominated the hydrocarbon distributions in <53 {mu}m particles in the oxic zone, while the isoprenoid C{sub 25}- and C{sub 40}-alkanes, 2,6,10,15,19-pentamethyleicosane and lycopane, dominated in the <53 {mu}m particles in the anoxic waters; petrogenic C{sub 17}-C{sub 40} n-alkanes dominated the >53 {mu}m particles. Particle size and depth distributions of the hydrocarbons demonstrate the importance of algal hydrocarbons in surface waters, coupled with increased abundances of bacterial hydrocarbons, especially in the <53 {mu}m particles, in the anoxic zone. These observations illustrate the importance of oxic-anoxic interfaces, even in the oceanic water column, as zones of intense microbial alteration of organic matter and as sources of some of the organic compounds found in sediments.

• OSTI ID: 6210733
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 54:5; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

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02 PETROLEUM
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CONCENTRATION RATIO
CONTINENTAL MARGIN
CONTINENTAL SHELF
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SEDIMENT-WATER INTERFACES
SEDIMENTARY BASINS
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