TY - JOUR
T1 - Influence of subsurface biosphere on geochemical fluxes from diffuse hydrothermal fluids
AU - Wankel, Scott D.
AU - Germanovich, Leonid N.
AU - Lilley, Marvin D.
AU - Genc, Gence
AU - Diperna, Christopher J.
AU - Bradley, Alexander S.
AU - Olson, Eric J.
AU - Girguis, Peter R.
N1 - Funding Information:
We would like to thank the R/V Atlantis crew and the DSV Alvin crew. Special thanks to S. Kelley and B. Strickrott for their assistance with the in situ mass spectrometer and flowmeter during deployment, as well as J. Robidart and B. Orcutt, who served as DSV Alvin chief scientists and collected ISMS data on dives 4419 and 4420. Special thanks go to R. Hurt and R. Lowell for their help in the design and calibration of the flowmeter. Helpful comments, useful discussion and assistance in the lab were provided by S. Shah, D. Johnston and C.H. Wankel. We are also grateful to J. Melas-Kyriazi for providing assistance with data management. Support for this research was provided, in part, by NSF OCE-0838107 and NASA-ASTEP grant no. 0910169 to P.R.G. and NSF OCE-0937057 to L.N.G.
PY - 2011/7
Y1 - 2011/7
N2 - Hydrothermal vents along mid-ocean systems host unique, highly productive biological communities, based on microbial chemoautotrophy, that thrive on the sulphur, metals, nitrogen and carbon emitted from the vents into the deep ocean. Geochemical studies of vents have centred on analyses of high-temperature, focused hydrothermal vents, which exhibit very high flow rates and are generally considered too hot for microbial life. Geochemical fluxes and metabolic activity associated with habitable, lower temperature diffuse fluids remain poorly constrained. As a result, little is known about the extent to which microbial communities, particularly in the subsurface, influence geochemical flux from more diffuse flows. Here, we estimate the net flux of methane, carbon dioxide and hydrogen from diffuse and focused hydrothermal vents along the Juan de Fuca ridge, using an in situ mass spectrometer and flowmeter. We show that geochemical flux from diffuse vents can equal or exceed that emanating from hot, focused vents. Notably, hydrogen concentrations in fluids emerging from diffuse vents are 50% to 80% lower than predicted. We attribute the loss of hydrogen in diffuse vent fluids to microbial consumption in the subsurface, and suggest that subsurface microbial communities can significantly influence hydrothermal geochemical fluxes to the deep ocean.
AB - Hydrothermal vents along mid-ocean systems host unique, highly productive biological communities, based on microbial chemoautotrophy, that thrive on the sulphur, metals, nitrogen and carbon emitted from the vents into the deep ocean. Geochemical studies of vents have centred on analyses of high-temperature, focused hydrothermal vents, which exhibit very high flow rates and are generally considered too hot for microbial life. Geochemical fluxes and metabolic activity associated with habitable, lower temperature diffuse fluids remain poorly constrained. As a result, little is known about the extent to which microbial communities, particularly in the subsurface, influence geochemical flux from more diffuse flows. Here, we estimate the net flux of methane, carbon dioxide and hydrogen from diffuse and focused hydrothermal vents along the Juan de Fuca ridge, using an in situ mass spectrometer and flowmeter. We show that geochemical flux from diffuse vents can equal or exceed that emanating from hot, focused vents. Notably, hydrogen concentrations in fluids emerging from diffuse vents are 50% to 80% lower than predicted. We attribute the loss of hydrogen in diffuse vent fluids to microbial consumption in the subsurface, and suggest that subsurface microbial communities can significantly influence hydrothermal geochemical fluxes to the deep ocean.
UR - http://www.scopus.com/inward/record.url?scp=79959921978&partnerID=8YFLogxK
U2 - 10.1038/ngeo1183
DO - 10.1038/ngeo1183
M3 - Article
AN - SCOPUS:79959921978
SN - 1752-0894
VL - 4
SP - 461
EP - 468
JO - Nature Geoscience
JF - Nature Geoscience
IS - 7
ER -