Quantitative assessment of methane turnover in shallow surface sediments of hydrate-bearing areas in Shenhu area of South China Sea
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摘要:
在天然气水合物发育区海底沉积物中甲烷厌氧氧化作用(AOM)是碳循环的重要组成部分。通过定量计算表层沉积物中甲烷迁移转化通量,可以更准确评估甲烷来源碳对沉积物碳库和海洋深部碳库影响。本文利用反应―运移模型对采集于南海神狐水合物发育区两个站位(SH-W19-PC、SH-W23-PC)采集的孔隙水SO42-、溶解无机碳(DIC)、Ca2+剖面进行拟合,同时对DIC碳同位素进行分析,确定近海底沉积物中的碳循环。研究显示两个站位孔隙水中SO42-和Ca2+浓度在剖面上随深度呈线性减少,DIC浓度随深度逐渐增加,其δ13CDIC值随深度逐渐降低至约-25‰,表明两个站位存在一定程度的AOM。模拟计算两个站位沉积物孔隙水溶解甲烷向上的通量分别为25.9和18.4 mmol·m-2 a-1,AOM作用产生的DIC分别占其总DIC量的70.7%和60%。由沉积物向海水中释放的DIC通量占DIC汇的约60%。因此,在天然气水合物发育区向海底渗漏甲烷大部分以DIC的形式进入上覆海水,这些具有极负碳同位素值的甲烷来源的DIC可能对局部深海碳库产生一定的影响。
Abstract:Anaerobic oxidation of methane (AOM) is an important process in the carbon cycle in marine sediments, especially in hydrate-bearing areas. By quantifying the pattern of methane migration and conversion flux in surface sediments, we can assess the impact of carbon, derived from methane, onto sediment carbon pool and deep ocean carbon pool more accurately. In this research, the reaction-migration model is used to fit the SO42−, dissolved inorganic carbon (DIC), and Ca2+ concentration of pore water and the carbon isotope of DIC is analyzed simultaneously at SH-W19-PC and SH-W23-PC Station, which are two typical hydrate-bearing areas in the Shenhu area of South China Sea. The analyzed results reveal that, the concentrations of SO42− and Ca2+ in the pore water of the two stations decrease linearly with depth, while the DIC concentration increases with depth. And the δ13CDIC value of the DIC in the pore water is near -25‰, indicating methane activity in these two stations. The numerical results show that the flux of dissolved methane in the pore water of the two stations are 25.9 mmol·m−2 a−1 and 18.4 mmol·m−2 a−1, respectively. And the content of DIC produced by AOM accounts for 70.7% and 60% of the total DIC content. In addition, the DIC flux released from sediment to seawater is about 60% of the DIC sink. Therefore, methane leaking from the cold seep area and hydrate-bearing area enters the overlying seawater partly in the form of DIC. These methane-derived DIC with extremely negative carbon isotope values may have a certain impact on the local deep sea carbon pool.
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表 1 SH-W19-PC和SH-W23-PC站位模型参数及边界条件
Table 1. Model parameters and boundary conditions at sites SH-W19-PC and SH-W23-PC
参数 SH-W19-PC SH-W23-PC 单位 温度(T) 5 5 ℃ 盐度(S) 33.5 33.5 % 压力(P) 105 105.1 bar 干燥固体密度(ρS) 2.5 2.5 g/cm3 沉积速率(ω)a 0.033 0.033 cm/a 沉积物-水界面孔隙度(φ0)b 0.7 0.7 — POC初始年龄(a0)c 40 40 ka SO42−在海水中的扩散系数c 191 191 cm2/a CH4在海水中的扩散系数c 294 294 cm2/a DIC在海水中的扩散系数d 203 203 cm2/a Ca2+在海水中的扩散系数c 142 142 cm2/a POC抑制系数(KC)e 35 35 mmol/L POC降解米氏常数(KSO42-)e 0.1 0.1 mmol/L AOM的动力系数(KAOM)e 1 1 cm3/(a·mmol) SO42−的上边界条件 28.2 28.2 mmol/L DIC的上边界条件 2.2 2.3 mmol/L Ca2+的上边界条件 11 11 mmol/L a为南海北部6个ODP184钻孔的平均值[52],b据Wang 等[52],c据Hu Y等[33],d基于碳酸氢根离子的分子扩散系数[27],e据Wallman 等[50]。 -
[1] Kvenvolden K A. Gas hydrate-geological perspective and global change [J]. Reviews of Geophysics, 1993, 31(2): 173-187. doi: 10.1029/93RG00268
[2] Buffett B, Archer D. Global inventory of methane clathrate: sensitivity to changes in the deep ocean [J]. Earth and Planetary Science Letters, 2004, 227(3-4): 185-199. doi: 10.1016/j.jpgl.2004.09.005
[3] Wallmann K, Pinero E, Burwicz E, et al. The global inventory of methane hydrate in marine sediments: a theoretical approach [J]. Energies, 2012, 5(7): 2449-2498. doi: 10.3390/en5072449
[4] Milkov A V. Global estimates of hydrate-bound gas in marine sediments: how much is really out there? [J]. Earth-Science Reviews, 2004, 66(3-4): 183-197. doi: 10.1016/j.earscirev.2003.11.002
[5] Knittel K, Boetius A. Anaerobic oxidation of methane: progress with an unknown process [J]. Annual Review of Microbiology, 2009, 63(1): 311-334. doi: 10.1146/annurev.micro.61.080706.093130
[6] Valentine D L, Kastner M, Wardlaw G D, et al. Biogeochemical investigations of marine methane seeps, Hydrate Ridge, Oregon [J]. Journal of Geophysical Research: Biogeosciences, 2015, 110(G2): G02005.
[7] Stakes D S, Orange D, Paduan J B, et al. Cold-seeps and authigenic carbonate formation in Monterey Bay, California [J]. Marine Geology, 1999, 159(1-4): 93-109. doi: 10.1016/S0025-3227(98)00200-X
[8] Komada T, Burdige D J, Li H L, et al. Organic matter cycling across the sulfate-methane transition zone of the Santa Barbara Basin, California borderland [J]. Geochimica et Cosmochimica Acta, 2016, 176: 259-278. doi: 10.1016/j.gca.2015.12.022
[9] Pohlman J W, Bauer J E, Waite W F, et al. Methane hydrate-bearing seeps as a source of aged dissolved organic carbon to the oceans [J]. Nature Geoscience, 2010, 4(1): 37-41.
[10] Haeckel M, Boudreau B P, Wallmann K. Bubble-induced porewater mixing: A 3-D model for deep porewater irrigation [J]. Geochimica et Cosmochimica Acta, 2007, 71(21): 5135-5154. doi: 10.1016/j.gca.2007.08.011
[11] Dickens G R. Global change: hydrocarbon-driven warming [J]. Nature, 2004, 429(6991): 513-515. doi: 10.1038/429513a
[12] Whiticar M J, Faber E, Schoell M. Biogenic methane formation in marine and freshwater environments: CO2 reduction vs. acetate fermentation—Isotope evidence [J]. Geochimica et Cosmochimica Acta, 1986, 50(5): 693-709. doi: 10.1016/0016-7037(86)90346-7
[13] Chen D F, Li X X, Xia B. Distribution features of gas hydrate stable zones and resource prediction of the Qiongdongnan basin in the South China Sea [J]. Chinese Journal of Geophysics, 2004, 47(3): 548-555. doi: 10.1002/cjg2.519
[14] Zhang H Q, Yang S X, Wu N Y, et al. Successful and surprising results for China's first gas hydrate drilling expedition [J]. Fire in the Ice: Methane Hydrate Newsletter, 2007, 7: 6-9.
[15] Zhang G X, Yang S X, Zhang M, Liang J, et al. GMGS2 expedition investigates rich and complex gas hydrate environment in the South China Sea [J]. Fire in the Ice: Methane Hydrate Newsletter, 2014, 14(1): 1-5.
[16] Yang S X, Zhang M, Liang J Q, et al. Preliminary results of China's third gas hydrate drilling expedition: a critical step from discovery to development in the South China Sea [J]. Fire in the Ice: Methane Hydrate Newsletter, 2015, 15(2): 1-5.
[17] Wu S, Zhang G, Huang Y, et al. Gas hydrate occurrence on the continental slope of the northern South China Sea [J]. Marine and Petroleum Geology, 2005, 22(3): 403-412. doi: 10.1016/j.marpetgeo.2004.11.006
[18] Deng H, Yan P, Liu H L, et al. Seismic data processing and the characterization of a gas hydrate bearing zone offshore of southwestern Taiwan [J]. Terrestrial, Atmospheric and Oceanic Sciences, 2006, 17(4): 781-797. doi: 10.3319/TAO.2006.17.4.781(GH)
[19] Yan P, Deng H, Liu H L. The geological structure and prospect of Gas Hydrate over the Dongsha slope, South China Sea [J]. Terrestrial, Atmospheric and Oceanic Sciences, 2006, 17(4): 645-658. doi: 10.3319/TAO.2006.17.4.645(GH)
[20] Suess E. RV SONNE Cruise Report SO177, Sino–German Cooperative Project, South China Sea Continental Margin: Geological Methane Budget and Environmental Effects of Methane Emissions and Gashydrates. IFM-GEOMAR Reports. 2005.
[21] 李学杰. 南海北部陆坡水合物初步研究: ODP钻孔证据[J]. 南海地质研究, 2004(1):16-28
LI Xuejie. Preliminary study of gas hydrate in the northern slope of the south china sea: evidences from ODP [J]. South China Sea Geology Research, 2004(1): 16-28.
[22] Hui G, Li S Z, Guo L L, et al. Source and accumulation of gas hydrate in the northern margin of the South China Sea [J]. Marine and Petroleum Geology, 2006, 69: 127-145.
[23] Feng J X, Yang S X, Liang J Q, et al. Methane seepage inferred from the porewater geochemistry of shallow sediments in the Beikang Basin of the southern South China Sea [J]. Journal of Asian Earth Sciences, 2018, 168: 77-86. doi: 10.1016/j.jseaes.2018.02.005
[24] Chen F, Hu Y, Feng D, et al. Evidence of intense methane seepages from molybdenum enrichments in gas hydrate-bearing sediments of the northern South China Sea [J]. Chemical Geology, 2016, 443: 173-181. doi: 10.1016/j.chemgeo.2016.09.029
[25] Hu Y, Feng D, Liang Q Y, et al. Impact of anaerobic oxidation of methane on the geochemical cycle of redox-sensitive elements at cold-seep sites of the northern South China Sea [J]. Deep Sea Research Part II: Topical Studies in Oceanography, 2015, 122: 84-94. doi: 10.1016/j.dsr2.2015.06.012
[26] Han X Q, Suess E, Huang Y Y, et al. Jiulong methane reef: Microbial mediation of seep carbonates in the South China Sea [J]. Marine Geology, 2008, 249(3-4): 243-256. doi: 10.1016/j.margeo.2007.11.012
[27] Luo M, Chen L Y, Wang S H, et al. Pockmark activity inferred from pore water geochemistry in shallow sediments of the pockmark field in southwestern Xisha Uplift, northwestern South China Sea [J]. Marine and Petroleum Geology, 2013, 48: 247-259. doi: 10.1016/j.marpetgeo.2013.08.018
[28] Tong H P, Feng D, Cheng H, et al. Authigenic carbonates from seeps on the northern continental slope of the South China Sea: New insights into fluid sources and geochronology [J]. Marine and Petroleum Geology, 2013, 43: 260-271. doi: 10.1016/j.marpetgeo.2013.01.011
[29] Feng D, Cheng M, Kiel S, et al. Using Bathymodiolus tissue stable carbon, nitrogen and sulfur isotopes to infer biogeochemical process at a cold seep in the South China Sea [J]. Deep Sea Research Part I: Oceanographic Research Papers, 2015, 104: 52-59. doi: 10.1016/j.dsr.2015.06.011
[30] Lin Z Y, Sun X M, Peckmann J, et al. How sulfate-driven anaerobic oxidation of methane affects the sulfur isotopic composition of pyrite: A SIMS study from the South China Sea [J]. Chemical Geology, 2016, 440: 26-41. doi: 10.1016/j.chemgeo.2016.07.007
[31] Chuang P C, Dale A W, Wallmann K, et al. Relating sulfate and methane dynamics to geology: accretionary prism offshore SW Taiwan [J]. Geochemistry, Geophysics, Geosystems, 2013, 14(7): 2523-2545. doi: 10.1002/ggge.20168
[32] 梁华崔, 梁前勇, 胡钰, 等. 南海东沙海域浅表层柱状沉积物孔隙水地球化学特征及对冷泉流体活动的指示[J]. 地球化学, 2017, 46(4):333-344 doi: 10.3969/j.issn.0379-1726.2017.04.004
LIANG Huacui, LIANG Qianyong, HU Yu, et al. Pore water geochemistry of shallow surface sediments in the Dongsha area of the South China Sea and its implications for the activities of cold seep fluids [J]. Geochimica, 2017, 46(4): 333-344. doi: 10.3969/j.issn.0379-1726.2017.04.004
[33] Hu Y, Luo M, Chen L Y, et al. Methane source linked to gas hydrate system at hydrate drilling areas of the South China Sea: Porewater geochemistry and numerical model constraints [J]. Journal of Asian Earth Sciences, 2018, 168: 87-95. doi: 10.1016/j.jseaes.2018.04.028
[34] 吴雪停, 刘丽华, Haeckel M, et al. 南海北部深海浅层沉积物中甲烷生物地球化学过程数值模拟研究[J]. 海洋地质与第四纪地质, 2016, 36(3):81-90
WU Xueting, LIU Lihua, Haeckel M, et al. Simulation of the biogeochemical processes in methane-bearing surface sediments of Haiyang 4 area, northern slope of south china sea [J]. Marine Geology & Quaternary Geology, 2016, 36(3): 81-90.
[35] Luo M, Dale A W, Wallmann K, et al. Estimating the time of pockmark formation in the SW Xisha Uplift (South China Sea) using reaction-transport modeling [J]. Marine Geology, 2015, 364: 21-31. doi: 10.1016/j.margeo.2015.03.006
[36] Hu Y, Luo M, Liang Q Y, et al. Pore fluid compositions and inferred fluid flow patterns at the Haima cold seeps of the South China sea [J]. Marine and Petroleum Geology, 2016, 103: 29-40.
[37] Ye H, Yang T, Zhu G R, et al. Pore water geochemistry in shallow sediments from the northeastern continental slope of the South China sea [J]. Marine and Petroleum Geology, 2016, 75: 68-82. doi: 10.1016/j.marpetgeo.2016.03.010
[38] 冯俊熙, 杨胜雄, 梁金强, 等. 南海北部神狐东南海域沉积物孔隙水地球化学特征及其对天然气水合物的指示[J]. 海洋地质前沿, 2017, 33(7):32-44
FENG Junxi, YANG Shengxiong, LIANG Jinqiang, et al. Pore water geochemistry in shallow sediments from southeastern shenhu area of northern south china sea and their implications for gas hydrate occurrence [J]. Marine Geology Frontiers, 2017, 33(7): 32-44.
[39] 郭依群, 杨胜雄, 梁金强, 等. 南海北部神狐海域高饱和度天然气水合物分布特征[J]. 地学前缘, 2017, 24(4):24-31
GUO Yiqun, YANG Shengxiong, LIANG Jinqiang, et al. Characteristics of high gas hydrate distribution in the Shenhu area on the northern slope of the South China Sea [J]. Earth Science Frontiers, 2017, 24(4): 24-31.
[40] Guo Y Q, Yang S X, Liang J Q, et al. Characteristics of high gas hydrate distribution in the Shenhu area on the northern slope of the South China Sea [J]. Earth Science Frontiers, 2017, 24(4): 24-31.
[41] Taylor B, Hayes D E. Origin and history of the South China Sea Basin[M]//Hayes D E. The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands. Washington, D.C.: American Geophysical Union, 1983, 27: 23-56.
[42] Sun Y B, Wu F, Clemens S C, et al. Processes controlling the geochemical composition of the South China Sea sediments during the last climatic cycle [J]. Chemical Geology, 2008, 257(3-4): 240-246. doi: 10.1016/j.chemgeo.2008.10.002
[43] 王存武, 陈红汉, 陈长民, 等. 珠江口盆地白云深水扇特征及油气成藏主控因素[J]. 地球科学—中国地质大学学报, 2007, 32(2):247-252, 266
WANG Cunwu, CHEN Honghan, CHEN Changmin, et al. Characteristics of the Baiyun deep-water fan and main accumulation controlling factors in Pearl River Mouth Basin, South China Sea [J]. Earth Science—Journal of China University of Geosciences, 2007, 32(2): 247-252, 266.
[44] Chen H, Savage P S, Teng F Z, et al. Zinc isotope fractionation during magmatic differentiation and the isotopic composition of the bulk Earth [J]. Earth and Planetary Science Letters, 2013, 369-370: 34-42. doi: 10.1016/j.jpgl.2013.02.037
[45] 王家豪, 庞雄, 王存武, 等. 珠江口盆地白云凹陷中央底辟带的发现及识别[J]. 地球科学—中国地质大学学报, 2006, 31(2):209-213
WANG Jiahao, PANG Xiong, WANG Cunwu, et al. Discovery and recognition of the central diapiric zone in Baiyun depression, Pearl River Mouth basin [J]. Earth Science-Journal of China University of Geosciences, 2006, 31(2): 209-213.
[46] 吴庐山, 杨胜雄, 梁金强, 等. 南海北部神狐海域沉积物中孔隙水硫酸盐梯度变化特征及其对天然气水合物的指示意义[J]. 中国科学: 地球科学, 2013, 56(3):530-540
WU Lushan, YANG Shengxiong, LIANG Jinqiang, et al. Variations of pore water sulphate gradients in sediments in indicator for underlying gas hydrate in shenhu area, the South China sea [J]. Chinese Science: Earth Science, 2013, 56(3): 530-540.
[47] 张伟, 梁金强, 何家雄, 等. 南海北部神狐海域GMGS1和GMGS3钻探区天然气水合物运聚成藏的差异性[J]. 天然气工业, 2018, 38(3):138-149
ZHANG Wei, LIANG Jiaqiang, HE Jiaxiong, et al. Differences in natural gas hydrate migration and accumulation between GMGS1 and GMGS3 drilling areas in the Shenhu area, northern South China Sea [J]. Natural Gas Industry, 2018, 38(3): 138-149.
[48] 吴能友, 杨胜雄, 王宏斌, 等. 南海北部陆坡神狐海域天然气水合物成藏的流体运移体系[J]. 地球物理学报, 2009, 52(6):1641-1650
WU Nengyou, YANG Shengxiong, WANG Hongbin, et al. Gas-bearing fluid influx sub-system for gas hydrate geological system in Shenhu Area, Northern South China Sea [J]. Chinese Journal of Geophysics, 2009, 52(6): 1641-1650.
[49] Sayles F L. Early Diagenesis: a theoretical approach. Robert A. Berner, Princeton University Press; Princeton, N.J., 1980; XII, 241 p., Princeton Series in Geochemistry, 25 cloth; 9 paper [J]. Geochimicaet Cosmochimica Acta, 1982, 46(2): 303-303.
[50] Wallmann K, Aloisi G, Haeckel M, et al. Kinetics of organic matter degradation, microbial methane generation, and gas hydrate formation in anoxic marine sediments [J]. Geochimica et Cosmochimica Acta, 2006, 70(15): 3905-3927. doi: 10.1016/j.gca.2006.06.003
[51] Van Cappellen P, Wang Y F. Cycling of iron and manganese in surface sediments; a general theory for the coupled transport and reaction of carbon, oxygen, nitrogen, sulfur, iron, and manganese [J]. American Journal of Science, 1996, 296(3): 197-243. doi: 10.2475/ajs.296.3.197
[52] Wang P, Prell W L, Blum P, et al. Proceedings of the Ocean Drilling Program, Initial Report 184, College Station, TX: Ocean Drilling Program, 2000.
[53] Jørgensen B B, Kasten S. Sulfur cycling and methane oxidation[M]//Schulz H D, Zabel M. Marine Geochemistry. Berlin, Heidelberg: Springer, 2006: 271-309.
[54] Reeburgh W S. Oceanic methane biogeochemistry [J]. Chemical Reviews, 2007, 107(2): 486-513. doi: 10.1021/cr050362v
[55] Regnier P, Dale A W, Arndt S, et al. Quantitative analysis of anaerobic oxidation of methane (AOM) in marine sediments: A modeling perspective [J]. Earth-Science Reviews, 2011, 106(1-2): 105-130. doi: 10.1016/j.earscirev.2011.01.002
[56] Middelburg J J. A simple rate model for organic matter decomposition in marine sediments [J]. Geochimica et Cosmochimica Acta, 1989, 53(7): 1577-1581. doi: 10.1016/0016-7037(89)90239-1
[57] Reeburgh W S. Methane consumption in Cariaco Trench waters and sediments [J]. Earth and Planetary Science Letters, 1976, 28(3): 337-344. doi: 10.1016/0012-821X(76)90195-3
[58] Boetius A, Ravenschlag K, Schubert C J, et al. A marine microbial consortium apparently mediating anaerobic oxidation of methane [J]. Nature, 2000, 407(6804): 623-626. doi: 10.1038/35036572
[59] Zhang Y P, Luo M, Hu Y, et al. An areal assessment of subseafloor carbon cycling in cold seeps and hydrate-bearing areas in the northern South China Sea [J]. Geofluids, 2019, 2019: 2573937.
[60] Borowski W R, Paull C K, Ussler III W. Global and local variations of interstitial sulfate gradients in deep-water, continental margin sediments: Sensitivity to underlying methane and gas hydrates [J]. Marine Geology, 1999, 159(1-4): 131-154. doi: 10.1016/S0025-3227(99)00004-3
[61] Egger M, Riedinger N, Mogollón J M, et al. Global diffusive fluxes of methane in marine sediments [J]. Nature Geoscience, 2018, 11(6): 421-425. doi: 10.1038/s41561-018-0122-8
[62] Wu L S, Yang S X, Liang J Q, et al. Variations of pore water sulfate gradients in sediments as indicator for underlying gas hydrate in Shenhu Area, the South China Sea [J]. Science China Earth Sciences, 2012, 56(4): 530-540.
[63] Hong W L, Sauer S, Panieri G, et al. Removal of methane through hydrological, microbial, and geochemical processes in the shallow sediments of pockmarks along eastern Vestnesa Ridge (Svalbard) [J]. Limnology and Oceanography, 2016, 61(S1): S324-S343. doi: 10.1002/lno.10299
[64] Hong W L, Torres M E, Kim J H, et al. Carbon cycling within the sulfate-methane-transition-zone in marine sediments from the Ulleung Basin [J]. Biogeochemistry, 2013, 115(1): 129-148.
[65] Berner R A. The carbon cycle and carbon dioxide over Phanerozoic time: the role of land plants [J]. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 1998, 353(1365): 75-82. doi: 10.1098/rstb.1998.0192
[66] Jahnke R A. The global ocean flux of particulate organic carbon: Areal distribution and magnitude [J]. Global Biogeochemical Cycles, 1996, 10(1): 71-88. doi: 10.1029/95GB03525
[67] Krumins V, Gehlen M, Arndt S, et al. Dissolved inorganic carbon and alkalinity fluxes from coastal marine sediments: model estimates for different shelf environments and sensitivity to global change [J]. Biogeosciences, 2013, 10: 371-398.
[68] Chuang P C, Yang T F, Wallmann K, et al. Carbon isotope exchange during anaerobic oxidation of methane (AOM) in sediments of the northeastern South China Sea [J]. Geochimica et Cosmochimica Acta, 2019, 246: 138-155. doi: 10.1016/j.gca.2018.11.003
[69] Schubert C J, Nielsen B. Effects of decarbonation treatments on δ13C values in marine sediments [J]. Marine Chemistry, 2000, 72(1): 55-59. doi: 10.1016/S0304-4203(00)00066-9
[70] Guan H X, Feng D, Wu N Y, et al. Fatty-acids and their δ13C characteristics of seep carbonates from the northern continental slope of Gulf of Mexico [J]. Chinese Science Bulletin, 2009, 55(8): 730-735.
[71] Campbell K A, Farmer J D, Des Marais D. Ancient hydrocarbon seeps from the Mesozoic convergent margin of California: carbonate geochemistry, fluids and palaeoenvironments [J]. Geofluids, 2010, 2(2): 63-94.
[72] 佟宏鹏, 冯东, 陈多福. 南海北部冷泉碳酸盐岩的矿物、岩石及地球化学研究进展[J]. 热带海洋学报, 2012, 31(5):45-56
TONG Hongpeng, FENG Dong, CHEN Duofu. Progresses on petrology, mineralogy and geochemistry of cold seep carbonates in the northern South China Sea [J]. Journal of Tropical Oceanography, 2012, 31(5): 45-56.
[73] Burdige D J, Komada T, Magen C, et al. Modeling studies of dissolved organic matter cycling in Santa Barbara Basin (CA, USA) sediments [J]. Geochimica et Cosmochimica Acta, 2016, 195: 100-119. doi: 10.1016/j.gca.2016.09.007
[74] Burdige D J. Sediment pore waters[M]//Hansell D A, Carlson C A. Biogeochemistry of Marine Dissolved Organic Matter. San Diego, CA: Academic Press, 2002: 611-663.
[75] Hung C W, Huang K H, Shih Y Y, et al. Benthic fluxes of dissolved organic carbon from gas hydrate sediments in the northern South China Sea [J]. Scientific Reports, 2016, 6: 29597. doi: 10.1038/srep29597