• Do different microbial communities populate different sedimentary geochemical regimes, or do these communities differ only in degree and kinds of community activity?
• How does the flow of electron acceptors through deeply buried sediments affect microbial communities and sediment geochemistry?
• To what extent do paleooceanographic conditions as preserved in deeply buried ocean sediments affect microbial communities currently inhabiting this part of the Earth's biosphere?

Sampling and research will be carried out to determine if deeply buried microbes migrate to follow concentrations of electron acceptors, to what extent they switch from one electron acceptor to another, or if they activate and deactivate as chemical fronts migrate past. Additionally, although methane in marine sediments constitutes one of the largest carbon reservoirs near the Earth's surface, the phylogenic affinities and community structure of methanogenic microbes in deeply buried subseafloor sediments is unknown. All of the proposed sites have been occupied by previous DSDP or ODP expeditions, and the results of this earlier research indicates the sites selected are uniquely suited to this investigation. The eastern equatorial Pacific sites show the occurrence of stable high methane and sulfate concentrations over a thick stratigraphic interval in disagreement with standard models. The Peru margin sites show a pronounced brine incursion that penetrates the methanogenic zone at depth and reverses the vertical sequence of electron acceptor availability in the sediments. These sites are also relatively close to sediments rich in dissolved methane, hydrate-rich sediments, and normal marine sediments for comparison.

These are proposed sites and may not all be drilled.

Leg	Prop #	Description	Site Prop	Lat. Prop	Long. Prop	Water Depth Prop.	Total Depth Prop
201	571	Peru	PRB-1A D	9°0.6'S	83°31.8'W	4487	155
	Full		PRB-2A D	12°1.2'S	81°34.8'W	4827	124
			PRU-02A	11°3.9'S	78°16.3'W	252.5	300
			PRU-01A	10°59'S	77°59'W	150.5	300
			PRU-03A	8°59'S	79°54.6'W	426	160
			PRU-04A	9°6.6'S	80°34.8'W	5070	300
			EQP-1A O	3°5.7'S	90°49.2'W	3314	400
			EQP-2A O	2°46.2'S	110°34.2'W	3780	318

Staff Scientist: Jay Miller

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Send comments to webmaster@odpemail .tamu.edu. Modified on Wednesday, 15-Aug-2001 16:38:25 CDT.