Contribution of “Old” carbon from natural marine hydrocarbon seeps to sedimentary and dissolved organic carbon pools in the Gulf of Mexico

Wang, Xu-Chen; Chen, Robert F.; Whelan, Jean K.; Eglinton, L.B.

doi:10.1029/2001gl013430

Cited by 45 publications

(37 citation statements)

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“…The DOC pool in sediment porewaters also reflected a significant contribution (up to 96%) from deep sediment CH4. In another study on the TX-LA Shelf, petroleum seeps were found to contribute 40% to 60% to the total organic C in a shallower slope region [17]. This study suggests a need for global consideration of the distribution of deep sediment CH4, especially hydrate bound methane, and the flux of carbon from this globally-significant carbon pool to shallow sediments.…”

Section: Discussionmentioning

confidence: 99%

“…This is a contrast to aerobic CH4 assimilation, where methane-derived carbon is directly incorporated into microbial biomass [15]. Deep sediment hydrocarbons, including CH4, have been shown to contribute to carbon cycling in shallow sediments and the water column [16][17][18][19][20][21]. However, the indirect contribution of hydrate-sourced CH4 to shallow sediment carbon pools through AOM and subsequent carbon dioxide (CO2) fixation has not been thoroughly evaluated.…”

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confidence: 99%

“…Shallow sediment CH4 in Atwater Valley, Gulf of Mexico has been shown to be dominated by biogenic gas from deep sediments [17]. In this study, two sites in Atwater Valley were contrasted: A sediment mound with active fluid advection and high vertical CH4 flux and an off-mound site exhibiting steady-state CH4 diffusion [22,23].…”

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confidence: 99%

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Deep Sediment-Sourced Methane Contribution to Shallow Sediment Organic Carbon: Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico

et al. 2015

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Coastal methane hydrate deposits are globally abundant. There is a need to understand the deep sediment sourced methane energy contribution to shallow sediment carbon relative to terrestrial sources and phytoplankton. Shallow sediment and porewater samples were collected from Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico near a seafloor mound feature identified in geophysical surveys as an elevated bottom seismic reflection. Geochemical data revealed off-mound methane diffusion and active fluid advection on-mound. Gas composition (average methane/ethane ratio ~11,000) and isotope ratios of methane on the mound (average δ CSOC = −629‰) suggest deep sourced ancient carbon is incorporated into shallow sediment organic matter. Porewater and sediment data indicate inorganic carbon fixed during anaerobic oxidation of methane is a dominant contributor to on-mound shallow sediment organic carbon cycling. A simple stable carbon isotope mass balance suggests carbon fixation of dissolved inorganic carbon (DIC) associated with anaerobic oxidation of hydrate-sourced CH4 contributes up to 85% of shallow sediment organic carbon.

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Section: Discussionmentioning

confidence: 99%

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Deep Sediment-Sourced Methane Contribution to Shallow Sediment Organic Carbon: Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico

et al. 2015

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“…DOC produced this way has distinctly old C-14 age and exports from seafloor into the ocean with circulating water from the "sub-seafloor ocean", providing a major source of old DOC in the ocean (Figure 8) [137]. Old DOC over 10 ka in age has been reported from a cold seepage off Vancouver Island [138], NE Pacific, from a low-temperature hydrothermal vent on ridge-flank off Juan de Fuca spreading ridge [139], and from deep-water hydrocarbon seepage in the Gulf of Mexico [140].…”

Section: Deep Biosphere and Deep Carbon Reservoirmentioning

confidence: 99%

Tracing the life history of a marginal sea—On “The South China Sea Deep” Research Program

Wang

2012

Chin. Sci. Bull.

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the first large-scale basic-research program in ocean science in the country aiming to reconstruct the life history of a marginal sea. The overall scientific objective of the program is to dissect this typical marginal sea by studying its history of evolution and its modern processes, including the following three major components: (1) Development of the deep basin: utilizing new techniques to re-measure magnetic anomaly lineations, to explore the deep tectonic features, to drill the oceanic crust, and to study volcanic seamount chains; (2) deep-water sediments: observing the modern processes to reveal the patterns of deep-water circulations and sedimentation, analyzing deep-sea sediments to recognize paleoceanographic response to basin evolution, and subsequently to bridge the modern and paleo-studies of the deep-sea processes; and (3) biogeochemical processes: using a variety of techniques including deploying submarine observation and deep-water diving device to investigate the distribution patterns and environmental impacts of deepwater seepages and subbottom circulation, and to reveal the role of microbes in deep-sea carbon cycling. As compared with the open ocean and other marginal seas, the South China Sea enjoys many more advantages as a marine basin for reconstructing the life history. Meanwhile, the South China Sea Deep Program provides unique opportunities in studying the evolution and variations of the sea-land interactions between the Pacific and Asia.the South China Sea Deep, marginal sea, deep-sea process, life history, tectonic evolution, sedimentological response, biogeochemistry Citation:Wang P X. Tracing the life history of a marginal

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“…Marine DOC is also a highly complex pool both in composition and dynamics (Benner 2002). Marine primary production is considered to be the major source of DOC to the ocean's interior (Williams and Druffel 1987;Opsahl and Benner 1997), but additional sources likely exist, including rivers and ocean margins (Bauer and Druffel 1998;Raymond and Bauer 2001;Dittmar and Kattner 2003;Bouillon et al 2008), hydrocarbon seeps (Wang et al 2001;Pohlman et al, 2011), hydrothermal systems , and sediment porewaters (Burdige et al 1999;Tremblay et al 2007).…”

Section: Marine Doc and Determination Of Its Isotopic Signaturesmentioning

confidence: 99%

Determination of radiocarbon in marine sediment porewater dissolved organic carbon by thermal sulfate reduction

Johnson

Komada

2011

Limnology & Ocean Methods

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Fractional abundances of 14 C and 13 C in dissolved organic carbon (DOC) in sediment porewaters may hold important clues about organic carbon cycling in sediments. Yet there is a dearth of isotopic signatures for porewater DOC because of the difficulty associated with oxidizing DOC in seawater. At present, marine DOC can be processed for analyses of 14 C and 13 C with high precision and minimal contamination by ultraviolet (UV) oxidation, but this method is resource intensive and could be difficult to implement. To resolve this, a thermal sulfate reduction (TSR) method, previously developed to determine 13 C in seawater DOC (Fry et al. 1996), was modified and tested for 14 C and 13 C determination in porewater DOC. CO 2 yields from six test materials ranged between 90% and 108%. d Application of TSR to archived porewater DOC samples from a sediment incubation experiment revealed notable changes in isotopic values that were not readily discerned in the DOC concentration data alone. The total uncertainty in the 14 C values after blank correction was ± 0.005 to 0.02 fraction modern (Fm) for sample sizes ranging between 143 and 560 µg C. For systems where precision on the order of ± 0.02 Fm is acceptable, TSR could be a viable alternative to UV oxidation for processing small, concentrated marine DOC samples. *Corresponding author: E-mail: tkomada@sfsu.edu AcknowledgmentsWe thank Ann McNichol for encouraging us to pursue this method and for sharing the protocol that she and Bill Martin developed. Sheila Griffin and Ellen Druffel generated the UV oxidation data, ran our AMS samples, and provided many helpful discussions. Xiaomei Xu provided assistance in radiocarbon data interpretation. Sabrina Crispo ran the TOC-V and assisted in the laboratory and in the field. We thank the captain and crew of R/V Point Sur, J. Polly, R. Paul, D. Burdige, M. Jinuntuya, and A. Pitts for the work conducted in the Santa Monica Basin. Three anonymous reviewers provided comments that helped improve the quality of this manuscript. This work was supported by NSF-OCE0726819 (TK) and James C Kelley Scholarship (LJ).Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of this research (ACS-PRF #46120-GB2 to TK). DOI 10.4319/lom.2011.9.485 Limnol. Oceanogr.: Methods 9, 2011, 485-498 © 2011, by the American Society of Limnology and Oceanography, Inc. LIMNOLOGY and OCEANOGRAPHY: METHODSues for marine porewater DOC have been reported in only a handful of studies (Bauer et al. 1995; Alperin et al. 2000).Several different methods have been developed to oxidize DOC to CO 2 for subsequent determination of 14 C and 13 C. As summarized by Bauer (2002), these can be broadly categorized into three types: (1) UV oxidation (Armstrong et al. 1966;Williams 1968; Williams et al. 1969; Williams and Gordon 1970;Druffel et al. 1989; Bauer et al. 1998;Beaupré et al. 2007), (2) sealed-tube dry combustion (Fry et al. 1993; Fry et al. 1996), and (3) flow-through high-temperature oxidation (Bauer ...

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Contribution of “Old” carbon from natural marine hydrocarbon seeps to sedimentary and dissolved organic carbon pools in the Gulf of Mexico

Cited by 45 publications

References 21 publications

Deep Sediment-Sourced Methane Contribution to Shallow Sediment Organic Carbon: Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico

Deep Sediment-Sourced Methane Contribution to Shallow Sediment Organic Carbon: Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico

Tracing the life history of a marginal sea—On “The South China Sea Deep” Research Program

Determination of radiocarbon in marine sediment porewater dissolved organic carbon by thermal sulfate reduction

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