@article {Larson2015,
	title = {{Stealth export of hydrogen and methane from a low temperature serpentinization system}},
	journal = {Deep-Sea Research Part II: Topical Studies in Oceanography},
	volume = {121},
	year = {2015},
	pages = {233{\textendash}245},
	abstract = {Chemical input to the deep sea from hydrothermal systems is a globally distributed phenomenon. Hydrothermal discharge is one of the primary mechanisms by which the Earth{\textquoteright}s interior processes manifest themselves at the Earth{\textquoteright}s surface, and it provides a source of energy for autotrophic processes by microbes that are too deep to capitalize on sunlight. Much is known about the water-column signature of this discharge from high-temperature mid-ocean Ridge (MOR) environments and their neighboring low-temperature counterparts. Hydrothermal discharge farther away from the ridge, however, has garnered less attention, owing in part to the difficulty in finding this style of venting, which eludes methods of detection that work well for high-temperature {\textquoteleft}black smoker{\textquoteright}-type venting. Here we present a case study of the plume from one such {\textquoteleft}invisible{\textquoteright} off-axis environment, The Lost City, with an emphasis on the dissolved volatile content of the hydrothermal plume. Serpentinization and abiotic organic synthesis generate significant concentrations of H2 and CH4 in vent fluid, but these species are unevenly transported to the overlying plume, which itself appears to be a composite of two different sources. A concentrated vent cluster on the talus slope channels fluid through at least eight chimneys, producing a water-column plume with the highest observed concentrations of CH4 in the field. In contrast, a saddle in the topography leading up to a carbonate cap hosts broadly distributed, nearly invisible venting apparent only in its water-column signals of redox potential and dissolved gas content, including the highest observed plume H2. After normalizing H2 and CH4 to the 3He background-corrected anomaly (3He$Δ$) to account for mixing and relative amount of mantle input, it appears that, while a minimum of 60{\%} of CH4 is transported out of the system, greater than 90{\%} of the H2 is consumed in the subsurface prior to venting. The exception to this pattern occurs in the plume originating from the area dubbed Chaff Beach, in which somewhat more than 10{\%} of the original H2 remains, indicating that this otherwise unremarkable plume, and others like it, may represent a significant source of H2 to the deep sea.},
	keywords = {AUV ABE (Autonomous Benthic Explorer), HOV Alvin (Human Occupied Vehicle)},
	doi = {10.1016/j.dsr2.2015.05.007},
	author = {Larson, B I and Lang, S Q and Lilley, M D and Olson, E J and Lupton, J E and Nakamura, K and Buck, N J}
}
@article {Lin2012,
	title = {{Inorganic chemistry, gas compositions and dissolved organic carbon in fluids from sedimented young basaltic crust on the Juan de Fuca Ridge flanks}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {85},
	year = {2012},
	pages = {213{\textendash}227},
	abstract = {The permeable upper oceanic basement serves as a plausible habitat for a variety of microbial communities. There is growing evidence suggesting a substantial subseafloor biosphere. Here new time series data are presented on key inorganic species, methane, hydrogen and dissolved organic carbon (DOC) in ridge flank fluids obtained from subseafloor observatory CORKs (Circulation Obviation Retrofit Kits) at Integrated Ocean Drilling Program (IODP) boreholes 1301A and 1026B. These data show that the new sampling methods (Cowen et al., 2012) employed at 1301A result in lower contamination than earlier studies. Furthermore, sample collection methods permitted most chemical analyses to be performed from aliquots of single large volume samples, thereby allowing more direct comparison of the data. The low phosphate concentrations (0.06{\textendash}0.2~$μ$M) suggest that relative to carbon and nitrogen, phosphorus could be a limiting nutrient in the basement biosphere. Coexisting sulfate (17{\textendash}18~mM), hydrogen sulfide (\~{}0.1~$μ$M), hydrogen (0.3{\textendash}0.7~$μ$M) and methane (1.5{\textendash}2~$μ$M) indicates that the basement aquifer at 1301A either draws fluids from multiple flow paths with different redox histories or is a complex environment that is not thermodynamically controlled and may allow co-occurring metabolic pathways including sulfate reduction and methanogenesis. The low DOC concentrations (11{\textendash}18~$μ$M) confirm that ridge flank basement is a net DOC sink and ultimately a net carbon sink. Based on the net amounts of DOC, oxygen, nitrate and sulfate removed (\~{}30~$μ$M, \~{}80~$μ$M, \~{}40~$μ$M and \~{}10~mM, respectively) from entrained bottom seawater, organic carbon may be aerobically or anaerobically oxidized in biotic and/or abiotic processes.},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2012.02.017},
	url = {http://dx.doi.org/10.1016/j.gca.2012.02.017},
	author = {Lin, H -T and Cowen, J P and Olson, E J and Amend, J P and Lilley, M D}
}
@article {Proskurowski2008,
	title = {{Stable isotopic evidence in support of active microbial methane cycling in low-temperature diffuse flow vents at 9 degrees 50{\textquoteright}N East Pacific Rise}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {72},
	number = {8},
	year = {2008},
	pages = {2005{\textendash}2023},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2008.01.025},
	url = {http://dx.doi.org/10.1016/j.gca.2008.01.025},
	author = {Proskurowski, G and Lilley, M D and Olson, E J}
}
@article {Larson2007,
	title = {{In situ measurement of dissolved chloride in high temperature hydrothermal fluids}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {71},
	number = {10},
	year = {2007},
	pages = {2510{\textendash}2523},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2007.02.013},
	url = {http://dx.doi.org/10.1016/j.gca.2007.02.013},
	author = {Larson, B I and Olson, E J and Lilley, M D}
}
@article {Proskurowski2006,
	title = {{Low temperature volatile production at the Lost City Hydrothermal Field: evidence from a hydrogen stable isotope geothermometer}},
	journal = {Chemical Geology},
	volume = {229},
	number = {4},
	year = {2006},
	pages = {331{\textendash}343},
	keywords = {AUV ABE (Autonomous Benthic Explorer), HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	issn = {0009-2541},
	doi = {10.1016/j.chemgeo.2005.11.005},
	url = {http://dx.doi.org/10.1016/j.chemgeo.2005.11.005},
	author = {Proskurowski, G and Lilley, M D and Kelley, D S and Olson, E J}
}
@article {Kelley2005a,
	title = {{A serpentinite-hosted ecosystem: The lost city hydrothermal field}},
	journal = {Science},
	volume = {307},
	number = {5714},
	year = {2005},
	pages = {1428{\textendash}1434},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0036-8075},
	doi = {10.1126/science.1102556},
	url = {http://dx.doi.org/10.1126/science.1102556},
	author = {Kelley, D S and Karson, J A and Fruh-Green, G L and Yoerger, D R and Shank, T M and Butterfield, D A and Hayes, J M and Schrenk, M O and Olson, E J and Proskurowski, G and Jakuba, M V and Bradley, A M and Larson, B I and Ludwig, K A and Glickson, D A and Buckman, K and Bradley, A S and Brazelton, W J and Roe, K and Elend, M J and Delacour, A and Bernasconi, S M and Lilley, M D and Baross, J A and Summons, R T and Sylva, S P}
}
@article {VonDamm2003,
	title = {{Extraordinary phase separation and segregation in vent fluids from the southern East Pacific Rise}},
	journal = {Earth and Planetary Science Letters},
	volume = {206},
	number = {3-4},
	year = {2003},
	month = {feb},
	pages = {365{\textendash}378},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0012-821X},
	doi = {10.1016/S0012-821X(02)01081-6},
	url = {http://dx.doi.org/10.1016/S0012-821X(02)01081-6},
	author = {Von Damm, K L and Lilley, M D and Shanks, W C and Brockington, M and Bray, A M and O{\textquoteright}Grady, K M and Olson, E J and Graham, A and Proskurowski, G and Party, SouEPR Science}
}
@article {Lilley2003,
	title = {{Magmatic events can produce rapid changes in hydrothermal vent chemistry}},
	journal = {Nature},
	volume = {422},
	number = {6934},
	year = {2003},
	pages = {878{\textendash}881},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	issn = {0028-0836},
	doi = {10.1038/nature01569},
	url = {http://dx.doi.org/10.1038/nature01569},
	author = {Lilley, M D and Butterfield, D A and Lupton, J E and Olson, E J}
}
@article {VanDover2001,
	title = {{Biogeography and ecological setting of Indian Ocean hydrothermal vents}},
	journal = {Science},
	volume = {294},
	number = {5543},
	year = {2001},
	pages = {818{\textendash}823},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0036-8075},
	doi = {10.1126/science.1064574},
	url = {http://dx.doi.org/10.1126/science.1064574},
	author = {Van Dover, C L and Humphris, S E and Fornari, D J and Cavanaugh, C M and Collier, R and Goffredi, S K and Hashimoto, J and Lilley, M D and Reysenbach, A -L and Shank, T M and Von Damm, K L and Banta, A and Gallant, R M and Gotz, D and Green, D and Hall, J and Harmer, T L and Hurtado, L A and Johnson, P and McKiness, Z P and Meredith, C and Olson, E J and Pan, I L and Turnipseed, M and Won, Y -J and Young, C R and Vrijenhoek, R C}
}
@article {Kelley2001a,
	title = {{An off-axis hydrothermal vent field near the Mid-Atlantic Ridge at 30 degrees N}},
	journal = {Nature},
	volume = {412},
	number = {6843},
	year = {2001},
	pages = {145{\textendash}149},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0028-0836},
	doi = {10.1038/35084000},
	url = {http://dx.doi.org/10.1038/35084000},
	author = {Kelley, D S and Karson, J A and Blackman, D K and Fruh-Green, G L and Butterfield, D A and Lilley, M D and Olson, E J and Schrenk, M O and Roe, K K and Lebon, G T and Rivizzigno, P}
}
