USC Wrigley Institute, AHF232, University of Southern California, Los Angeles, CA 90089, USA.
Archaeal diversity in ODP legacy borehole 892b and associated seawater and sediments of the Cascadia Margin
Version of Record online: 5 JAN 2006
FEMS Microbiology Ecology
Volume 54, Issue 2, pages 167–177, October 2005
How to Cite
Lanoil, B. D., La Duc, M. T., Wright, M., Kastner, M., Nealson, K. H. and Bartlett, D. (2005), Archaeal diversity in ODP legacy borehole 892b and associated seawater and sediments of the Cascadia Margin. FEMS Microbiology Ecology, 54: 167–177. doi: 10.1016/j.femsec.2005.03.015
- Issue online: 5 JAN 2006
- Version of Record online: 5 JAN 2006
- Received 12 December 2004, Revised 18 March 2005, Accepted 18 March 2005
- Cascadia Margin;
- 16S rRNA;
- Ocean Drilling Project (ODP)
The Cascadia Margin is a region of active accretionary tectonics characterized by high methane flux accompanied by the formation of sedimentary gas hydrates, carbonate nodules, and carbonate pavements. Several sediment cores have been obtained from this region by the Ocean Drilling Project (ODP), and in some cases the boreholes have been sealed off, serving as sites for long-term observatories. We characterized geochemical parameters and diversity of Archaea in one such “legacy” borehole, ODP site 892b, as well as in bottom water immediately above the borehole and in two nearby sediments. The methane concentrations in the samples varied over five orders of magnitude, from 25 to 35 nM in the bottom water to 1.4 mM in one of the sediment samples. Despite these differences, the Archaeal community in all samples was dominated by gene sequences related to the methanogenic Archaea, a finding that correlates with studies of other environments characterized by high methane flux. The archaeal phylotype richness in borehole ODP 892b was limited to two phylotypes; one specifically related to Methanosaeta spp., the other to the anaerobic methane oxidizing ANME-1 group. Although some similar groups were observed in nearby sediment and seawater samples, their archaeal phylotype richness was significantly higher than in the borehole. The possible presence of a dynamic microbial community in the Cascadia Margin sub-surface and its potential roles in methanogenesis, anaerobic oxidation of methane, and authigenic precipitation of carbonate in the Cascadia Margin are discussed.