Abstract
Continental margins in world oceans contain large amounts of marine gas hydrates. Changes in the temperature and pressure of sediment may destabilize the methane hydrate, leading to its release and seepage into the sea. This process would increase the dissolved methane in the ambient seawater. In this study, a methane sensor was used to detect methane anomalies in the water column in southwestern Dongsha and Shenhu, northern slope of the South China Sea. Methane plumes were detected at stations SCS001 and T001 in the southwestern Dongsha area, and station SCS002 in the Shenhu area, respectively. The maximum methane concentrations were 8.8 nmol/L in southwestern Dongsha and 10.1 nmol/L in Shenhu, which are about 4–5 times higher than the background methane concentration. This indicates that there are active methane seepages present in both the southwestern Dongsha and Shenhu areas, which are likely related to a methane hydrate reservoir beneath the seafloor. A methane sensor with a low detection limit is a practical instrument with which to detect methane plumes in oceanic environments and to monitor methane leakage from the seafloor.
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References
Burke Jr R A, Reid D F, Brooks J M, Lavoie D M. 1983. Upper water column methane geochemistry in the eastern tropical North Pacific. Limnology and Oceanography, 28(1): 19–32.
Han X Q, Suess E, Huang Y Y, Wu N Y, Bohrmann G, Su X, Eisenhauer A, Rehder G, Fang Y X. 2008. Jiulong Methane Reef: Microbial mediation of seep carbonates in the South China Sea. Marine Geology, 249(3–4): 243–256.
Han X Q, Suess E, Liebetrau V, Eisenhauer A, Huang Y Y. 2014. Past methane release events and environmental conditions at the upper continental slope of the South China Sea: constraints by seep carbonates. International Journal of Earth Sciences, 103(7): 1 873–1 887.
Han X Q, Yang K H, Huang Y Y. 2013. Origin and nature of cold seep in northeastern Dongsha area, South China Sea: Evidence from chimney–like seep carbonates. Science Bulletin, 58(30): 3 689–3 697.
Huang Y Y, Suess E, Wu N Y. 2005. Geological setting and evidences of gas hydrate occurring in the North–east Dongsha area of South China Sea. Proceedings of Gas Hydrate Colloquium between Taiwan and Motherland, Tainan. p.3–4.(in Chinese with English abstract)
Kelley C A, Jeffrey W H. 2002. Dissolved methane concentration profiles and air–sea fluxes from 41°S to 27°N. Global Biogeochemical Cycles, 16(3): 13–1–13–6.
Kvenvolden K A. 1993. Gas hydrates–geological perspective and global change. Reviews Geophysics, 31(2): 173–187.
Li S J, Chu F Y, Fang Y X, Wu Z Y, Ni Y G. 2010. Associated interpretation of sub–bottom and single–channel seismic profiles from slope of Shenhu Area in the northern South China Sea—characteristics of gas hydrate sediment. Journal of Tropical Oceanography, 29(4): 56–62.(in Chinese with English abstract)
Lu H F, Chen F, Liu J, Liao Z L, Sun X M, Su X. 2006. Characteristics of authigenic carbonate chimneys in Shenhu area, northern South China Sea: recorders of hydrocarbon–enriched fluid activity. Geological Review, 52(3): 352–357.(in Chinese with English abstract)
McInerney F A, Wing S L. 2011. The paleocene–eocene thermal maximum: a perturbation of carbon cycle, climate, and biosphere with implications for the future. Annual Review of Earth & Planetary Sciences, 39(11): 489–516.
Milkov A V. 2004. Global estimates of hydrate–bound gas in marine sediments: how much is really out there? Earth–Science Reviews, 66(3–4): 183–197.
Reeburgh W S. 2007. Oceanic methane biogeochemistry. Chemical Reviews, 107(2): 486–513.
Ruppel C D, Kessler J D. 2017. The interaction of climate change and methane hydrates. Reviews of Geophysics, 55(1): 126–168.
Sauter E J, Muyakshin S I, Charlou J L, Schlüter M, Boetius A, Jerosch K, Damm E, Foucher J P, Klages M. 2006. Methane discharge from a deep–sea submarine mud volcano into the upper water column by gas hydratecoated methane bubbles. Earth and Planetary Science Letters, 243(3–4): 354–365.
Shang J H, Li J B, Zhang J B. 2008. Contrast of seismic reflection characteristics of gas hydrate distribution between northeast SCS slope and Hengchun ridge. Marine Science Bulletin, 10(1): 64–74.
Tilbrook B D, Karl D M. 1995. Methane sources, distributions and sinks from California coastal waters to the oligotrophic North Pacific gyre. Marine Chemistry, 49(1): 51–64.
Traganza E D, Swinnerton J W, Cheek C H. 1979. Methane supersaturation and ATP–zooplankton blooms in nearsurface waters of the Western Mediterranean and the subtropical North Atlantic Ocean. Deep Sea Research Part A. Oceanographic Research Papers, 26(11): 1 237–1 245.
Ward B B, Kilpatrick K A, Wopat A E, Minnich E C, Lidstrom M E. 1989. Methane oxidation in Saanich inlet during summer stratification. Continental Shelf Research, 9(1): 65–75.
Wu N Y, Zhang H Q, Yang S X, Liang J Q, Wang H B. 2007. Preliminary discussion on natural gas hydrate(NGH) reservoir system of Shenhu area, north slope of South China Sea. Natural Gas Industry, 27(9): 1–6.(in Chinese with English abstract)
Yao B C. 2007. The forming condition and distribution characteristics of the gas hydrate in the South China Sea. Offshore Oil, 27(1): 1–10.(in Chinese with English abstract)
Yin X J, Zhou H Y, Yang Q H, Wang H, Chen J. 2008. The evidence for the existence of methane seepages in the northern South China Sea: abnormal high methane concentrations in bottom waters. Acta Oceanologica Sinica, 27(6): 62–70.
Zhang G L, Zhang J. 2001. Advances in studies of dissolved methane in seawater. Advance in earth Sciences, 16(6): 829–835.(in Chinese with English abstract)
Zhang G X, Yang S X, Zhang M, Liang J Q, Lu J G, Holland M, Schultheiss P, the GMGS2 ScienceTeam. 2014. GMGS2 expedition investigates rich and complex gas hydrate environment in the South China Sea. Methane Hydrate Newsletter, 14(1): 1–5.
Zhou H Y, Wu Z J, Peng X T, Jiang L, Tang S. 2007. Detection of methane plumes in the water column of Logatchev hydrothermal vent field, Mid–Atlantic Ridge. Chinese Science Bulletin, 52(15): 2 140–2 146.
Zhou H Y, Yin X J, Yang Q H, Wang H, Wu Z J, Bao S X. 2009. Distribution, source and flux of methane in the western Pearl River Estuary and northern South China Sea. Marine Chemistry, 117(1–4): 21–31.
Acknowledgement
The authors appreciate the assistance of all cruise members on the RV/ Dayangyihao during the DY 21 cruise. Thanks to Akiningbagbe Akintoye Edward, and Enago (www.enago.cn), for English language editing. We thank Anika Burkard Newell, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.
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Supported by the National Key R&D Program of China (No. 2017YFC0306701), the National Natural Science Foundation of China (No. 41106052), and the Fundamental Research Funds for National Nonprofit Institute Grant (No. JG1511)
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Qiu, Z., Han, X. & Wang, Y. Methane seepages in the northern South China Sea: evidence from in situ measurements. J. Ocean. Limnol. 36, 1556–1561 (2018). https://doi.org/10.1007/s00343-018-7052-6
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DOI: https://doi.org/10.1007/s00343-018-7052-6