@article {ISI:000371206300001,
	title = {{A distinct and active bacterial community in cold oxygenated fluids circulating beneath the western flank of the Mid-Atlantic ridge}},
	journal = {SCIENTIFIC REPORTS},
	volume = {6},
	year = {2016},
	month = {mar},
	type = {Article},
	abstract = {The rock-hosted, oceanic crustal aquifer is one of the largest ecosystems on Earth, yet little is known about its indigenous microorganisms. Here we provide the first phylogenetic and functional description of an active microbial community residing in the cold oxic crustal aquifer. Using subseafloor observatories, we recovered crustal fluids and found that the geochemical composition is similar to bottom seawater, as are cell abundances. However, based on relative abundances and functional potential of key bacterial groups, the crustal fluid microbial community is heterogeneous and markedly distinct from seawater. Potential rates of autotrophy and heterotrophy in the crust exceeded those of seawater, especially at elevated temperatures (25 degrees C) and deeper in the crust. Together, these results reveal an active, distinct, and diverse bacterial community engaged in both heterotrophy and autotrophy in the oxygenated crustal aquifer, providing key insight into the role of microbial communities in the ubiquitous cold dark subseafloor biosphere.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {2045-2322},
	doi = {10.1038/srep22541},
	author = {Meyer, Julie L and Jaekel, Ulrike and Tully, Benjamin J and Glazer, Brian T and Wheat, C Geoffrey and Lin, Huei-Ting and Hsieh, Chih-Chiang and Cowen, James P and Hulme, Samuel M and Girguis, Peter R and Huber, Julie A}
}
@article {ISI:000276314000001,
	title = {{Fluid sources and pathways of the Costa Rica erosional convergent margin}},
	journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
	volume = {11},
	year = {2010},
	month = {apr},
	type = {Article},
	abstract = {The margins community has only relatively recently begun to examine the tectonics and associated hydrologic systems of erosive convergent margins, which are substantially different as compared with accretionary margins. In this respect, the type example erosive margin is the Costa Rica system, which has been the subject of numerous recent large-scale investigations. Here pore fluids expelled at the wedge toe and at midslope mounds and mud volcanoes have been interpreted to have a common deep source of dehydrating clays, analogous to that at accretionary margins. However, we report unusually high B/Li molar ratios in pore fluids from a recent mudflow on Mound 11, offshore Costa Rica, which, together with unusually low B/Li ratios previously reported at the wedge toe, reveal that alternative fluid sources and/or processes must be operating at the Costa Rica margin. As serpentine formation is the only subduction zone process that significantly fractionates B and Li, we propose that the difference in fluid chemical composition is the result of erosion of upper plate serpentinites, ongoing serpentinization, and serpentine mineral phase transitions in the subduction channel. These processes provide both a source of fluids and fluid pathways that lead to the unique geochemical signature observed at this erosional margin. This conclusion is compatible with, and supported by, the current view of the tectonics, geology, and hydrogeology of the Costa Rica margin and the similarity of the pore fluid to that of two other convergent margins, both with known fluid/serpentinite interactions.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1525-2027},
	doi = {10.1029/2009GC002818},
	author = {Tryon, Michael D and Wheat, C Geoffrey and Hilton, David R}
}
@article {ISI:000280324500002,
	title = {{Subseafloor seawater-basalt-microbe reactions: Continuous sampling of borehole fluids in a ridge flank environment}},
	journal = {GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS},
	volume = {11},
	year = {2010},
	month = {jul},
	type = {Article},
	abstract = {Integrated Ocean Drilling Program (IODP) Hole 1301A was drilled, cased, and instrumented with a long-term, subseafloor observatory (CORK) on the eastern flank of the Juan de Fuca Ridge in summer 2004. This borehole is located 1 km south of ODP Hole 1026B and 5 km north of Baby Bare outcrop. Hole 1301A penetrates 262 m of sediment and 108 m of the uppermost 3.5 Ma basaltic basement in an area of warm (64 degrees C) hydrothermal circulation. The borehole was instrumented, and those instruments were recovered 4 years later. Here we report chemical data from two continuous fluid samplers (OsmoSamplers) and temperature recording tools that monitored changes in the state of borehole (formation) fluids. These changes document the effects of drilling, fluid overpressure and flow, seawater-basalt interactions, and microbial metababolic activity. Initially, bottom seawater flowed into the borehole through a leak between concentric CORK casing strings. Eventually, the direction of flow reversed, and warm, altered formation fluid flowed into the borehole and discharged at the seafloor. This reversal occurred during 1 week in September 2007, 3 years after drilling operations ceased. The composition of the formation fluid around Hole 1301A generally lies within bounds defined by springs on Baby Bare outcrop (to the south) and fluids that discharged from Hole 1026B (to the north); deviations likely result from reactions with drilling products. Simple conservative mixing of two end-member fluids reveals reactions occurring within the crust, including nitrate reduction presumably by denitrifying microbes. The observed changes in borehole fluid composition provide the foundation for a conceptual model of chemical and microbial change during recharge of a warm ridge-flank hydrothermal system. This model can be tested through future scientific ocean drilling experiments.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1525-2027},
	doi = {10.1029/2010GC003057},
	author = {Wheat, C Geoffrey and Jannasch, Hans W and Fisher, Andrew T and Becker, Keir and Sharkey, Jessica and Hulme, Samuel}
}
