@article {Gueguen2016,
	title = {{Comparative geochemistry of four ferromanganese crusts from the Pacific Ocean and significance for the use of Ni isotopes as paleoceanographic tracers}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {189},
	year = {2016},
	pages = {214{\textendash}235},
	abstract = {{Ferromanganese (Fe-Mn) crusts are potential archive of the Ni isotope composition of seawater through time. In this study we aim at (1) understanding Ni isotope fractionation mechanisms and metal enrichment processes in Fe-Mn deposits, (2) addressing global vs. local control of Ni isotope composition of these deposits. Two Fe-Mn crusts from the North Pacific Ocean (Apuupuu Seamount, Hawaii) and two Fe-Mn crusts from the South Pacific Ocean (near Rurutu Island, Austral archipelago of French Polynesia) were characterized for their elemental geochemistry and Ni isotope composition. Geochemical analyses were performed at millimeter intervals in order to provide time-resolved record of Ni isotopes. Chronology and growth rates were determined using cosmogenic 10Be isotope abundances. The results show that, despite different growth rates, textures and geochemical patterns, Fe-Mn crusts from both North and South Pacific Oceans have fairly homogenous Ni isotope compositions over the last \~{}17 Ma, yielding average $δ$60/58Ni values of 1.79 {\textpm} 0.21{\textperthousand} (2sd},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.gca.2016.06.005},
	author = {Gueguen, B and Rouxel, O J and Rouget, M-L and Bollinger, C and Ponzevera, E and Germain, Y and Fouquet, Y}
}
@article {Rouxel2016,
	title = {{Geochemistry and iron isotope systematics of hydrothermal plume fall-out at East Pacific Rise 9{\textdegree}50'N}},
	journal = {Chemical Geology},
	volume = {441},
	year = {2016},
	pages = {212{\textendash}234},
	abstract = {While gross hydrothermal fluxes entering the ocean are known to be significant, much remains unknown about the fate of this material as it disperses through the oceans, and its impact upon ocean biogeochemistry. Mineral precipitation within hydrothermal plumes removes hydrothermally-sourced metals from solution and also acts to scavenge trace elements from the surrounding water column. Here, we investigate the fate of particulate Fe released from high-temperature hydrothermal venting at EPR 9{\textdegree}50'N and its potential impact on local deep-ocean Fe-isotopic and geochemical budgets. We measured the geochemical composition, mineralogy and Fe isotope systematics of hydrothermal plume products in order to determine whether mineral precipitation imposes characteristic Fe-isotope {\textquotedblleft}fingerprints{\textquotedblright} for hydrothermally sourced Fe in the deep ocean. Our sampling includes sediment trap deployments after the eruptive event of Jan. 2006, allowing the examination of temporal changes of hydrothermal fluxes over a 160 day period. Results show that Fe isotope composition in the high-temperature vent fluids is rather constant over the sampling period 2004{\textendash}2008, and that secular variations of $δ$56Fe values of plume particles from - 0.03 to - 0.91{\textperthousand} (relative to IRMM-14 standard) could be explained by local processes leading to variable mixing extents of hydrothermal, biogenic and lithogenic particles. Through geochemical modeling, we have calculated the relative abundances of hydrothermal plume components such as sulfides, Fe oxyhydroxides, organic matter, biogenic and lithogenic phases. We demonstrate that Fe isotope fractionation in the hydrothermal plume occurs during the formation and rapid settling of Fe-sulfides that are characterized by $δ$56Fe values ranging from - 0.73 {\textpm} 0.13{\textperthousand} to - 0.86 {\textpm} 0.13{\textperthousand}, which is systematically lower than the end-member hydrothermal fluids ($δ$56Fe = - 0.4{\textperthousand}). This study suggests that both the initial Fe isotope composition of the high-temperature vent fluids and its initial Fe/H2S ratio (i.e. Fe-sulfide precipitation versus Fe-oxyhydroxide precipitation) should impose characteristic Fe isotope {\textquotedblleft}fingerprints{\textquotedblright} for hydrothermally derived Fe in the deep ocean.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	doi = {10.1016/j.chemgeo.2016.08.027},
	author = {Rouxel, O J and Toner, B M and Manganini, S J and German, C R}
}
@article {Escoube2015,
	title = {{Coupled Ge/Si and Ge isotope ratios as geochemical tracers of seafloor hydrothermal systems: Case studies at Loihi Seamount and East Pacific Rise 9{\textdegree}50'N}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {167},
	year = {2015},
	pages = {93{\textendash}112},
	abstract = {Germanium (Ge) and Silicon (Si) exhibit similar geochemical behavior in marine environments but are variably enriched in seafloor hydrothermal fluids relative to seawater. In this study, Ge isotope and Ge/Si ratio systematics were investigated in low temperature hydrothermal vents from Loihi Seamount (Pacific Ocean, 18{\textdegree}54'N, 155{\textdegree}15'W) and results were compared to high-temperature vents from the East Pacific Rise (EPR) at 9{\textdegree}50'N. Loihi offers the opportunity to understand contrasting Ge and Si behavior in low temperature seafloor hydrothermal systems characterized by abundant Fe oxyhydroxide deposition at the seafloor. The results show that both Ge/Si and $δ$74/70Ge in hydrothermal fluids are fractionated relative to the basaltic host rocks. The enrichment in Ge vs. Si relative to fresh basalts, together with Ge isotope fractionation ($Δ$74/70Gefluid-basalt up to 1.15{\textperthousand} at EPR 9{\textdegree}50'N and 1.64{\textperthousand} at Loihi) are best explained by the precipitation of minerals (e.g. quartz and Fe-sulfides) during higher temperature seawater{\textendash}rock reactions in the subsurface. The study of Fe-rich hydrothermal deposits at Loihi, largely composed of Fe-oxyhydroxides, shows that Ge isotopes are also fractionated upon mineral precipitation at the seafloor. We obtained an average Ge isotope fractionation factor between Fe-oxyhydroxide (ferrihydrite) and dissolved Ge in the fluid of -2.0 {\textpm} 0.6{\textperthousand} (2sd), and a maximum value of -3.6 {\textpm} 0.6{\textperthousand} (2sd), which is consistent with recent theoretical and experimental studies. The study of a hydrothermal chimney at Bio 9 vent at EPR 9{\textdegree}50'N also demonstrates that Ge isotopes are fractionated by approximately -5.6 {\textpm} 0.6{\textperthousand} (2sd) during precipitation of metal sulfides under hydrothermal conditions. Using combined Ge/Si and estimated Ge isotope signatures of Ge sinks and sources in seawater, we propose a preliminary oceanic budget of Ge which reveals that an important sink, referred as the {\textquotedblleft}missing Ge sink{\textquotedblright}, may correspond to Ge sequestration into authigenic Fe-oxyhydroxides in marine sediments. This study shows that combining Ge/Si and $δ$74/70Ge systematics provides a useful tool to trace hydrothermal Ge and Si sources in marine environments and to understand formation processes of seafloor hydrothermal deposits.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.gca.2015.06.025},
	author = {Escoube, R and Rouxel, O J and Edwards, K J and Glazer, B and Donard, O F X}
}
@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 {Adams2011,
	title = {{Surface-generated mesoscale eddies transport deep-sea products from hydrothermal vents}},
	journal = {Science},
	volume = {332},
	number = {6029},
	year = {2011},
	pages = {580{\textendash}583},
	abstract = {Atmospheric forcing, which is known to have a strong influence on surface ocean dynamics and production, is typically not considered in studies of the deep sea. Our observations and models demonstrate an unexpected influence of surface-generated mesoscale eddies in the transport of hydrothermal vent efflux and of vent larvae away from the northern East Pacific Rise. Transport by these deep-reaching eddies provides a mechanism for spreading the hydrothermal chemical and heat flux into the deep-ocean interior and for dispersing propagules hundreds of kilometers between isolated and ephemeral communities. Because the eddies interacting with the East Pacific Rise are formed seasonally and are sensitive to phenomena such as El Ni{\~n}o, they have the potential to introduce seasonal to interannual atmospheric variations into the deep sea.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0036-8075},
	doi = {10.1126/science.1201066},
	url = {http://dx.doi.org/10.1126/science.1201066},
	author = {Adams, D K and McGillicuddy, D J and Zamudio, L and Thurnherr, A M and Liang, X and Rouxel, O J and German, C R and Mullineaux, L S}
}
@article {Craddock2010a,
	title = {{Rare earth element abundances in hydrothermal fluids from the Manus Basin, Papua New Guinea: indicators of sub-seafloor hydrothermal processes in back-arc basins}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {74},
	number = {19},
	year = {2010},
	pages = {5494{\textendash}5513},
	abstract = {Rare earth element (REE) concentrations are reported for a large suite of seafloor vent fluids from four hydrothermal systems in the Manus back-arc basin (Vienna Woods, PACMANUS, DESMOS and SuSu Knolls vent areas). Sampled vent fluids show a wide range of absolute REE concentrations and chondrite-normalized (REEN) distribution patterns (LaN /SmN \~{} 0.6{\textendash}11; LaN /YbN \~{} 0.6 {\textendash} 71; View the MathML sourceEuN/EuN*\~{}1{\textendash}55). REEN distribution patterns in different vent fluids range from light-REE enriched, to mid- and heavy-REE enriched, to flat, and have a range of positive Eu-anomalies. This heterogeneity contrasts markedly with relatively uniform REEN distribution patterns of mid-ocean ridge hydrothermal fluids. In Manus Basin fluids, aqueous REE compositions do not inherit directly or show a clear relationship with the REE compositions of primary crustal rocks with which hydrothermal fluids interact. These results suggest that the REEs are less sensitive indicators of primary crustal rock composition despite crustal rocks being the dominant source of REEs in submarine hydrothermal fluids. In contrast, differences in aqueous REE compositions are consistently correlated with differences in fluid pH and ligand (chloride, fluoride and sulfate) concentrations. Our results suggest that the REEs can be used as an indicator of the type of magmatic acid volatile (i.e., presence of HF, SO2) degassing in submarine hydrothermal systems. Additional fluid data suggest that near-seafloor mixing between high-temperature hydrothermal fluid and locally entrained seawater at many vent areas in the Manus Basin causes anhydrite precipitation. Anhydrite effectively incorporates REE and likely affects measured fluid REE concentrations, but does not affect their relative distributions.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2010.07.003},
	url = {http://dx.doi.org/10.1016/j.gca.2010.07.003},
	author = {Craddock, P R and Bach, W and Seewald, J S and Rouxel, O J and Reeves, E and Tivey, M K}
}
@article {Glazer2009,
	title = {{Redox speciation and distribution within diverse iron-dominated microbial habitats at Loihi Seamount}},
	journal = {Geomicrobiology Journal},
	volume = {26},
	number = {8},
	year = {2009},
	pages = {606{\textendash}622},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {0149-0451},
	doi = {10.1080/01490450903263392},
	url = {http://dx.doi.org/10.1080/01490450903263392},
	author = {Glazer, B T and Rouxel, O J}
}
@article {Rouxel2008,
	title = {{Integrated Fe- and S-isotope study of seafloor hydrothermal vents at East Pacific Rise 9{\textendash}10 degrees N}},
	journal = {Chemical Geology},
	volume = {252},
	number = {3-4},
	year = {2008},
	pages = {214{\textendash}227},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0009-2541},
	doi = {10.1016/j.chemgeo.2008.03.009},
	url = {http://dx.doi.org/10.1016/j.chemgeo.2008.03.009},
	author = {Rouxel, O J and Shanks, W C and Bach, W and Edwards, K J}
}
@article {John2008,
	title = {{Zinc stable isotopes in seafloor hydrothermal vent fluids and chimneys}},
	journal = {Earth and Planetary Science Letters},
	volume = {269},
	number = {1-2},
	year = {2008},
	pages = {17{\textendash}28},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2007.12.011},
	url = {http://dx.doi.org/10.1016/j.epsl.2007.12.011},
	author = {John, S G and Rouxel, O J and Craddock, P R and Engwall, A M and Boyle, E A}
}
