@article {2615,
	title = {Microbial decomposition of marine dissolved organic matter in cool oceanic crust},
	journal = {Nature Geoscience},
	volume = {11},
	year = {2018},
	month = {Jan-05-2018},
	pages = {334 - 339},
	abstract = {Marine dissolved organic carbon (DOC) is one of the largest active reservoirs of reduced carbon on Earth. In the deep ocean, DOC has been described as biologically recalcitrant and has a radiocarbon age of 4,000 to 6,000 years, which far exceeds the timescale of ocean overturning. However, abiotic removal mechanisms cannot account for the full magnitude of deep-ocean DOC loss. Deep-ocean water circulates at low temperatures through volcanic crust on ridge flanks, but little is known about the associated biogeochemical processes and carbon cycling.
Here we present analyses of DOC in fluids from two borehole observatories installed in crustal rocks west of the Mid-Atlantic Ridge, and show that deep-ocean DOC is removed from these cool circulating fluids. The removal mechanism is isotopically selective and causes a shift in specific features of molecular composition, consistent with microbe-mediated oxidation. We suggest organic molecules with an average radiocarbon age of 3,200 years are bioavailable to crustal microbes, and that this removal mechanism may account for at least 5\% of the global loss of DOC in the deep ocean. Cool crustal circulation probably contributes to maintaining the deep ocean as a reservoir of {\textquoteright}aged{\textquoteright} and refractory DOC by discharging the surviving organic carbon constituents that are molecularly degraded and depleted in C-14 and C-13 into the deep ocean.},
	keywords = {carbon, community, deep-ocean, DISTINCT, extraction, fluid-flow, HEAT, MID-ATLANTIC RIDGE, SEAWATER, WESTERN FLANK},
	issn = {1752-0894},
	doi = {10.1038/s41561-018-0109-5},
	url = {http://www.nature.com/articles/s41561-018-0109-5http://www.nature.com/articles/s41561-018-0109-5.pdfhttp://www.nature.com/articles/s41561-018-0109-5http://www.nature.com/articles/s41561-018-0109-5.pdf},
	author = {Shah Walter, Sunita R. and Jaekel, Ulrike and Osterholz, Helena and Fisher, Andrew T. and Huber, Julie A. and Pearson, Ann and Dittmar, Thorsten and Girguis, Peter R.}
}
@article {1962,
	title = {Biogeochemical investigations of marine methane seeps, Hydrate Ridge, Oregon},
	journal = {Journal of Geophysical Research-Biogeosciences},
	volume = {110},
	year = {2005},
	note = {090wnTimes Cited:19
Cited References Count:72
},
	month = {Nov 10},
	pages = {1-17},
	abstract = {[1] A series of biogeochemical studies were conducted at the southern summit of Hydrate Ridge, offshore Oregon. Using the submersible DSV Alvin, sediment push cores were collected from two distinct seep environments characterized by the presence of clam fields (CF) or microbial mats (MM) at the sediment-water interface; samples were also collected from a nearby reference site characterized by a barren surface at the sediment-water interface. Sediment samples from each setting were analyzed for the depth distributions of total organic carbon (concentrations, delta C-13 and Delta C-14), total sedimentary nitrogen, and microbial abundance. Pore fluids were extracted and analyzed for sulfate, alkalinity, sulfide, organic carbon, and volatile organic acids. These depth distributions clearly indicate the presence of three distinctive biogeochemical settings in the surface sediments of Hydrate Ridge, and provide the basis for a comparative biogeochemical analysis. Both CF and MM sites display properties indicating enhanced microbial activity in the subsurface, compared with the reference site. MM sites display evidence of net biomass production in the subsurface; however, a loss of sediment nitrogen relative to the reference site indicates that mineralization is also enhanced. Calculations based on the removal of nitrogen indicate that greater than 30\% of autochthonous organic material is lost to enhanced mineralization in the top 23 cm of one MM site. An isotope mass balance of sediment-bound organic carbon indicates a mixed source, including methane and allochthonous organic carbon dissolved in the seep fluids. The concentrations of organic carbon dissolved in seep fluids reach values of 22 mM and provide a first indication that advective transport of dissolved organic carbon from great depth may supply an important source of energy and carbon to "methane seep{\textquoteright}{\textquoteright} communities.},
	keywords = {anaerobic oxidation, authigenic carbonates, cascadia convergent margin, community structure, dissolved organic-carbon, fluid-flow, ne pacific, odp site 892b, phylogenetic analysis, sulfate-reducing bacteria},
	isbn = {0148-0227},
	doi = {10.1029/2005JG000025},
	url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&amp;SrcAuth=Alerting\&amp;SrcApp=Alerting\&amp;DestApp=WOS\&amp;DestLinkType=FullRecord;UT=WOS:000240984200001},
	author = {Valentine, D. L. and Kastner, M. and Wardlaw, G. D. and Wang, X. C. and Purdy, A. and Bartlett, D. H.}
}
