@article {McDermott2015,
	title = {{Identification of sulfur sources and isotopic equilibria in submarine hot-springs using multiple sulfur isotopes}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {160},
	year = {2015},
	pages = {169{\textendash}187},
	abstract = {Multiple sulfur isotopes were measured in metal sulfide deposits, elemental sulfur, and aqueous hydrogen sulfide to constrain sulfur sources and the isotopic systematics of precipitation in seafloor hydrothermal vents. Areas studied include the Eastern Manus Basin and Lau Basin back-arc spreading centers and the unsedimented basalt-hosted Southern East Pacific Rise (SEPR) and sediment-hosted Guaymas Basin mid-ocean ridge spreading centers. Chalcopyrite and dissolved hydrogen sulfide (H2S) $δ$34S values range from -5.5{\textperthousand} to +5.6{\textperthousand} in Manus Basin samples, +2.4{\textperthousand} to +6.1{\textperthousand} in Lau Basin samples, and +3.7{\textperthousand} to +5.7{\textperthousand} in SEPR samples. Values of $δ$34S for cubic cubanite and H2S range from -1.4{\textperthousand} to +4.7{\textperthousand} in Guaymas Basin samples. Multiple sulfur isotope systematics in fluid-mineral pairs from the SEPR and Lau Basin show that crustal host rock and thermochemical reduction of seawater-derived dissolved sulfate (SO4) are the primary sources of sulfur in mid-ocean ridge and some back-arc systems. At PACMANUS and SuSu Knolls hydrothermal systems in the Eastern Manus Basin, a significant contribution of sulfur is derived from disproportionation of magmatic sulfur dioxide (SO2), while the remaining sulfur is derived from crustal host rocks and SO4 reduction. At the sedimented Guaymas Basin hydrothermal system, sulfur sources include crustal host rock, reduced seawater SO4, and biogenic sulfide. Vent fluid flow through fresher, less-mature sediment supplies an increased quantity of reactant organic compounds that may reduce 34S-enriched SO4, while fluid interaction with more highly-altered sediments results in H2S characterized by a small, but isotopically-significant input of 34S-depleted biogenic sulfides. Near-zero $Δ$33S values in all samples implicate the abiotic processes of SO4 reduction and leaching of host rock as the major contributors to sulfur content at a high temperature unsedimented mid-ocean ridge and at a back-arc system. $Δ$33S values indicate that SO2 disproportionation is an additional process that contributes sulfur to a different back-arc system and to acid spring-type hydrothermal fluid circulation. At the sedimented Guaymus Basin, near-zero $Δ$33S values are also observed, despite negative $δ$34S values that indicate inputs of biogenic pyrite for some samples. In contrast with previous studies reporting isotope disequilibrium between H2S and chalcopyrite, the $δ$34S values of chalcopyrite sampled from the inner 1{\textendash}2 mm of a chimney wall are within {\textpm}1{\textperthousand} of $δ$34S values for H2S in the paired vent fluid, suggesting equilibrium fluid-mineral sulfur isotope exchange at 300{\textendash}400 {\textdegree}C. Isotopic equilibrium between hydrothermal fluid H2S and precipitating chalcopyrite implies that sulfur isotopes in the chalcopyrite lining across a chimney wall may accurately record past hydrothermal activity.},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.gca.2015.02.016},
	author = {McDermott, J M and Ono, S and Tivey, M K and Seewald, J S and Shanks, W C}
}
@article {Bennett2011,
	title = {{Dissolved and particulate organic carbon in hydrothermal plumes from the East Pacific Rise, 9 degrees 50'N}},
	journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
	volume = {58},
	number = {9},
	year = {2011},
	pages = {922{\textendash}931},
	abstract = {Chemoautotrophic production in seafloor hydrothermal systems has the potential to provide an important source of organic carbon that is exported to the surrounding deep-ocean. While hydrothermal plumes may export carbon, entrained from chimney walls and biologically rich diffuse flow areas, away from sites of venting they also have the potential to provide an environment for in-situ carbon fixation. In this study, we have followed the fate of dissolved and particulate organic carbon (DOC and POC) as it is dispersed through and settles beneath a hydrothermal plume system at 9{\textdegree}50'N on the East Pacific Rise. Concentrations of both DOC and POC are elevated in buoyant plume samples that were collected directly above sites of active venting using both DSV Alvin and a CTD-rosette. Similar levels of POC enrichment are also observed in the dispersing non-buoyant plume, \~{}500~m downstream from the vent-site. Further, sediment-trap samples collected beneath the same dispersing plume system, show evidence for a close coupling between organic carbon and Fe oxyhydroxide fluxes. We propose, therefore, a process that concentrates POC into hydrothermal plumes as they disperse through the deep-ocean. This is most probably the result of some combination of preferential adsorption of organic carbon onto Fe-oxyhydroxides and/or microbial activity that preferentially concentrates organic carbon in association with Fe-oxyhydroxides (e.g. through the microbial oxidation of Fe(II) and Fe sulfides). This potential for biological production and consumption within hydrothermal plumes highlights the importance of a multidisciplinary approach to understanding the role of the carbon cycle in deep-sea hydrothermal systems as well as the role that hydrothermal systems may play in regulating global deep-ocean carbon budgets.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0967-0637},
	doi = {10.1016/j.dsr.2011.06.010},
	url = {http://dx.doi.org/10.1016/j.dsr.2011.06.010},
	author = {Bennett, S A and Statham, P J and Green, D R H and Le Bris, N and McDermott, J M and Prado, F and Rouxel, O J and Von Damm, K L and German, C R}
}
@article {German2010,
	title = {{Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise}},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {107},
	number = {32},
	year = {2010},
	month = {aug},
	pages = {14020{\textendash}14025},
	abstract = {Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world{\textquoteright}s ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the similar to 110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at similar to 5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity-all in close proximity.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0027-8424},
	doi = {10.1073/pnas.1009205107},
	author = {German, C R and Bowen, A and Coleman, M L and Honig, D L and Huber, J A and Jakuba, M V and Kinsey, J C and Kurz, M D and Leroy, S and McDermott, J M and de Lepinay, B M and Nakamura, K and Seewald, J S and Smith, J L and Sylva, S P and Van Dover, C L and Whitcomb, L L and Yoerger, D R}
}
