Authors: HongXiang Guan Dong Feng NengYou Wu DuoFu Chen H H Roberts DaiDai Wu
Publish Date: 2009/07/27
Volume: 55, Issue: 8, Pages: 730-735
Abstract
Here we reported the fattyacids and their δ 13C values in seep carbonates collected from Green Canyon lease block 185 GC 185 Sample GCF at upper continental slope water depth ∼540 m and Alaminos Canyon lease block 645 GC 645 Sample ACE at lower continental slope water depth ∼2200 m of the Gulf of Mexico More than thirty kinds of fatty acids were detected in both samples These fatty acids are maximized at C16 There is a clear evenoverodd carbon number predominance in carbon number range The fatty acids are mainly composed of nfatty acids iso/anteisofatty acids and terminally branched oddnumbered fatty acids iso/anteiso The low δ 13C values −3999‰ to3236‰ of nC120 nC130 iC140 and nC140 suggest that they may relate to the chemosynthetic communities at seep sites The unsaturated fatty acids nC182 and C181Δ9 have the same δ 13C values they may originate from the Beggiatoa/Thioploca Unlike other fatty acids the terminally branched fatty acids iso/anteiso show lower δ 13C values as low as −6395‰ suggesting a possible relationship to sulfate reducing bacteria which is common during anaerobic oxidation of methane at seep sites
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