@article {Bennett2013,
	title = {{Trophic regions of a hydrothermal plume dispersing away from an ultramafic-hosted vent-system: Von Damm vent-site, Mid-Cayman Rise}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {14},
	number = {2},
	year = {2013},
	pages = {317{\textendash}327},
	abstract = {Deep-sea ultramafic-hosted vent systems have the potential to provide large amounts of metabolic energy to both autotrophic and heterotrophic microorganisms in their dispersing hydrothermal plumes. Such vent-systems release large quantities of hydrogen and methane to the water column, both of which can be exploited by autotrophic microorganisms. Carbon cycling in these hydrothermal plumes may, therefore, have an important influence on open-ocean biogeochemistry. In this study, we investigated an ultramafic-hosted system on the Mid-Cayman Rise, emitting metal-poor and hydrogen sulfide-, methane-, and hydrogen-rich hydrothermal fluids. Total organic carbon concentrations in the plume ranged between 42.1 and 51.1 $μ$M (background = 43.2 {\textpm} 0.7 $μ$M (n = 5)) and near-field plume samples with elevated methane concentrations imply the presence of chemoautotrophic primary production and in particular methanotrophy. In parts of the plume characterized by persistent potential temperature anomalies but lacking elevated methane concentrations, we found elevated organic carbon concentrations of up to 51.1 $μ$M, most likely resulting from the presence of heterotrophic communities, their extracellular products and vent larvae. Elevated carbon concentrations up to 47.4 $μ$M were detected even in far-field plume samples. Within the Von Damm hydrothermal plume, we have used our data to hypothesize a microbial food web in which chemoautotrophy supports a heterotrophic community of microorganisms. Such an active microbial food web would provide a source of labile organic carbon to the deep ocean that should be considered in any future studies evaluating sources and sinks of carbon from hydrothermal venting to the deep ocean.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {1525-2027},
	doi = {10.1002/ggge.20063},
	url = {http://dx.doi.org/10.1002/ggge.20063},
	author = {Bennett, S A and Coleman, Max and Huber, J A and Reddington, E and Kinsey, J C and McIntyre, C and Seewald, J S and German, C R}
}
@article {Bennett2011a,
	title = {{Tracing iron-fueled microbial carbon production within the hydrothermal plume at the Loihi Seamount}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {75},
	number = {19},
	year = {2011},
	pages = {5526{\textendash}5539},
	abstract = {The Loihi hydrothermal plume provides an opportunity to investigate iron (Fe) oxidation and microbial processes in a system that is truly Fe dominated and distinct from mid-ocean ridge spreading centers. The lack of hydrogen sulfide within the Loihi hydrothermal fluids and the presence of an oxygen minimum zone at this submarine volcano{\textquoteright}s summit, results in a prolonged presence of reduced Fe within the dispersing non-buoyant plume. In this study, we have investigated the potential for microbial carbon fixation within the Loihi plume. We sampled for both particulate and dissolved organic carbon in hydrothermal fluids, microbial mats growing around vents, and the dispersing plume, and carried out stable carbon isotope analysis on the particulate fraction. The $δ$13C values of the microbial mats ranged from -23{\textperthousand} to -28{\textperthousand}, and are distinct from those of deep-ocean particulate organic carbon (POC). The mats and hydrothermal fluids were also elevated in dissolved organic carbon (DOC) compared to background seawater. Within the hydrothermal plume, DOC and POC concentrations were elevated and the isotopic composition of POC within the plume suggests mixing between background seawater POC and a 13C-depleted hydrothermal component. The combination of both DOC and POC increasing in the dispersing plume that cannot solely be the result of entrainment and DOC adsorption, provides strong evidence for in-situ microbial productivity by chemolithoautotrophs, including a likelihood for iron-oxidizing microorganisms.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2011.06.039},
	url = {http://dx.doi.org/10.1016/j.gca.2011.06.039},
	author = {Bennett, S A and Hansman, R L and Sessions, A L and Nakamura, K and Edwards, K J}
}
