1. Archaeal Lipids and 16S rRNA Genes Characterizing Non-hydrate and Hydrate-Impacted Sediments in the Gulf of Mexico.
- Author
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Pi, Yundan, Ye, Qi, Jiang, Hongchen, Wang, Peng, Li, Shuguang, Noakes, John, Culp, Randy, Dong, Hailiang, and Zhang, Chuanlun
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PHYLOGENY , *MARINE sediments , *SEDIMENTS , *GEOLOGY education , *GAS hydrates - Abstract
This study reports the intact lipids and the phylogenetic compositions of archaea from marine sediments adjacent to or within a region of methane seeps and hydrate mounds in the Mississippi Canyon (MC) Block 118 in the Gulf of Mexico. An aliquot of lyophilized sediment (∼5 g) was extracted for total lipids. Fractions of the glycerol dialkyl glycerol tetraethers (GDGTs) were obtained through column fractionation and determined using liquid-chromatography-mass spectrometry. DNA was extracted from a different aliquot of the sample (∼7 g) that was kept at -80°C. GDGTs showed distinct patterns between non-hydrate and hydrate-impacted samples, suggesting dramatically different archaeal communities caused by the presence of gas hydrates or cold seeps. Clone libraries of 16S rRNA genes were constructed to provide a phylogenetic explanation of the archaeal populations possibly causing the variation in lipid profiles. In contrast to the non-thermophilic crenarchaeota-dominant species in the normal marine sediment, the hydrate-impacted samples showed the predominance of ANME-1 subgroups with Thermoplasmatales being secondarily abundant; both of them are known to produce tetraether lipids and may be responsible for the enhanced archaeal lipids in the hydrate samples. MC 118 is designed to be a seafloor observatory in the Gulf of Mexico and our study represents the initial efforts in characterizing archaeal populations and their role in carbon cycle at this location. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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