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DaiDai Wu
Key Laboratory of Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of sciences, Guangzhou 510640, China.

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Journal article
Published: 23 September 2019 in International Journal of Environmental Research and Public Health
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Anaerobic oxidation of methane (AOM) is a common biochemical process in the ocean and it plays an important role in global climate change, elemental circulation, and atmospheric evolution over geological time. In this paper, we analyzed of δ34S, Fe, Mn, Ca/Ti, and Sr/Ti ratios, and the date of carbon and sulfur from the site SH3 of Shenhu area. Result showed that (1) 0-6 mbsf (meter blow the sea floor) was mainly affected by OSR (anaerobic oxidation of organic matters) and 7-15 mbsf was a paleo-SMTZ (sulfate-methane transition zone) position. The modern SMTZ was mainly distributed at 19-25 mbsf. The barium sulfate precipitation above the modern SMTZ indicating that the current methane leakage was stable and lasted longer during geological history. (2) By studying the change of magnetic and the different carbonate minerals, results showed that there were two AOM stages. During the early stage, Fe2+ were mainly produced by sulfide abiotic reductive dissolution. During the later stage, Fe2+ were mainly produced by the metal-AOM. (3) Study of the mineral characteristics of the paleo-SMTZ and the modern SMTZ showed that the modern SMTZ carbonate minerals were mainly low-Mg calcite and aragonite, while the paleo-SMTZ carbon minerals were mainly high Mg minerals. The reason for this difference is that the modern SMTZ layer was only experienced the first stage of anaerobic oxidation of methane. In the paleo-SMTZ layer, it has experienced two stage of anaerobic oxidation of methane. During the last stage of metal-AOM, the low Mg carbonate minerals were converted into high Mg carbonate minerals. This research confirms the presence of metal-driven methane anaerobic oxidation at the bottom of sulfate-driven methane anaerobic oxidation and during the metal-driven methane anaerobic oxidation, methane and metal oxides or hydroxides would couple to convert the in situ metal oxides or hydroxides into metal ions, meanwhile the phosphorus adsorbed on the surface of the metal oxides is released into adjacent pore water, and convert to new P-bearing minerals under suitable conditions.

ACS Style

Rui Xie; DaiDai Wu; Jie Liu; Tiantian Sun; Lihua Liu; Nengyou Wu. Geochemical Evidence of Metal-Driven Anaerobic Oxidation of Methane in the Shenhu Area, the South China Sea. International Journal of Environmental Research and Public Health 2019, 16, 3559 .

AMA Style

Rui Xie, DaiDai Wu, Jie Liu, Tiantian Sun, Lihua Liu, Nengyou Wu. Geochemical Evidence of Metal-Driven Anaerobic Oxidation of Methane in the Shenhu Area, the South China Sea. International Journal of Environmental Research and Public Health. 2019; 16 (19):3559.

Chicago/Turabian Style

Rui Xie; DaiDai Wu; Jie Liu; Tiantian Sun; Lihua Liu; Nengyou Wu. 2019. "Geochemical Evidence of Metal-Driven Anaerobic Oxidation of Methane in the Shenhu Area, the South China Sea." International Journal of Environmental Research and Public Health 16, no. 19: 3559.

Article
Published: 09 July 2019 in Acta Oceanologica Sinica
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Recent studies have shown that specific geochemical characteristics of sediments can be used to reconstruct past methane seepage events. In this work, the correlation between the Sr/Ca and Mg/Ca ratios of sediment samples is analyzed and the sulfate concentration profile in Site C14 from cold-seep sediments in the Qiongdongnan Basin in northern South China Sea is obtained. The results confirmed that, sulfate at 0-247 cm below sea floor (Unit I) is mainly consumed by organic matter sulfate reduction (OSR), while sulfate at 247-655 cm (Unit II) is consumed by both the OSR and the anaerobic oxidation of methane (AOM). In addition, the bottom sediment layer is affected by weak methane seepage. The Mo and U enrichment factors also exhibit similar trends in their respective depth profiles. The responses of trace elements, including Co/Al, Ni/Al, Cr/Al and Zn/Al ratios to methane seepage allowed the study of depositional conditions and methane seepage events. Based on the results, it is speculated that the depositional conditions of Unit II changed with depth from moderate conditions of sulfidic and oxic conditions to locally anoxic conditions, and finally to suboxic conditions due to methane fluid leakage. The stable isotope values of chromium-reducible sulfide produced by AOM and those of sulfide formed by OSR in the early diagenetic environment suffered serious depletion of 34S. This was probably due to weak methane leakage, which caused the slower upward diffusion and the effect of early diagenesis on the samples. It is necessary to consider the effects of depositional environments and diagenesis on these geochemical parameters.

ACS Style

Tiantian Sun; DaiDai Wu; Fei Yang; Lihua Liu; Xuegang Chen; Ying Ye. Sedimentary geochemical proxies for methane seepage at Site C14 in the Qiongdongnan Basin in the northern South China Sea. Acta Oceanologica Sinica 2019, 38, 84 -95.

AMA Style

Tiantian Sun, DaiDai Wu, Fei Yang, Lihua Liu, Xuegang Chen, Ying Ye. Sedimentary geochemical proxies for methane seepage at Site C14 in the Qiongdongnan Basin in the northern South China Sea. Acta Oceanologica Sinica. 2019; 38 (7):84-95.

Chicago/Turabian Style

Tiantian Sun; DaiDai Wu; Fei Yang; Lihua Liu; Xuegang Chen; Ying Ye. 2019. "Sedimentary geochemical proxies for methane seepage at Site C14 in the Qiongdongnan Basin in the northern South China Sea." Acta Oceanologica Sinica 38, no. 7: 84-95.

Journal article
Published: 28 June 2019 in International Journal of Environmental Research and Public Health
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Sediments at marine cold seep areas provide potential archives of past fluid flow, which allow insights into the evolution of past methane seepage activities. However, signals for anaerobic oxidation of methane (AOM) might be obscured in bulk sediments in cold-seep settings due to several factors, especially flood and turbidite deposition. Comprehensive inorganic data were gathered in this study to explore the availability of related records at cold seeps and to provide insights into the evolution of past methane seepage activities. Sediments collected from the site 973-4 in the Taixinan Basin on the northern slope of the South China Sea were characterized in terms of total carbon and sulfur, δ13C values of total organic carbon (δ13CTIC), δ34S values of chromium reducible sulfur (δ34SCRS), and foraminiferal oxygen and carbon isotopes. The results confirmed a strong correlation between formation of authigenic minerals and AOM. Moreover, the 34S enrichments and abundant chromium reducible sulfur (CRS) contents in the authigenic sulfides in the sulfate-methane transition zone (SMTZ) within 619-900 cm below seafloor (cmbsf) reflected past high methane fluxes supported by constant methane seepages. Lithological distribution and AMS (Accelerator Mass Spectra) 14C dating of planktonic foraminifera show that the turbidite (~35.14 ka) was related to a foraminifera-rich interval (Unit II: 440-619 cmbsf) and increased carbonate productivity during the last glacial maximum (LGM). Enrichment of Mo and U was observed accompanied by low contents of nutrient metals (Al, Ti, V, Ni, Fe, Mn, and Cu) in Unit II. The foraminifera-rich interval (Unit II) of cold seep sediments was probably linked to the phenomenon of inconsecutive sedimentary sequence due to the turbidites, which resulted in the lack of Fe, Mn, and Ba enrichment. There is no U enrichment but only Mo enrichment within Unit III, which might be related to H2S produced by AOM during the methane seepages. Based on the above results, it can be speculated that this area has experienced multiple-episodes of methane seep events. Further exploration of AOM should focus on the risks of rapid deposition, especially the impact of turbidity current on sediments.

ACS Style

DaiDai Wu; Tiantian Sun; Rui Xie; Mengdi Pan; Xuegang Chen; Ying Ye; Lihua Liu; Nengyou Wu. Characteristics of Authigenic Minerals around the Sulfate-Methane Transition Zone in the Methane-Rich Sediments of the Northern South China Sea: Inorganic Geochemical Evidence. International Journal of Environmental Research and Public Health 2019, 16, 2299 .

AMA Style

DaiDai Wu, Tiantian Sun, Rui Xie, Mengdi Pan, Xuegang Chen, Ying Ye, Lihua Liu, Nengyou Wu. Characteristics of Authigenic Minerals around the Sulfate-Methane Transition Zone in the Methane-Rich Sediments of the Northern South China Sea: Inorganic Geochemical Evidence. International Journal of Environmental Research and Public Health. 2019; 16 (13):2299.

Chicago/Turabian Style

DaiDai Wu; Tiantian Sun; Rui Xie; Mengdi Pan; Xuegang Chen; Ying Ye; Lihua Liu; Nengyou Wu. 2019. "Characteristics of Authigenic Minerals around the Sulfate-Methane Transition Zone in the Methane-Rich Sediments of the Northern South China Sea: Inorganic Geochemical Evidence." International Journal of Environmental Research and Public Health 16, no. 13: 2299.

Journal article
Published: 22 April 2019 in International Journal of Environmental Research and Public Health
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Cold seep emissions of low temperature fluid from the marine sediment basins are mainly comprised of methane and other hydrocarbons. A series of biogeochemical processes related to methane lead to the formation of authigenic carbonate minerals. In this study, a self-built experimental device was used to study the formation process of carbonate minerals under cold seep conditions. The concentrations of pore water chemicals, HCO3- and Ca2+ at different heights of the reactor under flow conditions can be observed. According to the experimental results, the formation process of carbonate minerals under cold seep conditions was estimated, that 1 m carbonate growth needs 12,000 and 7000 years, respectively, under fast (5 mL·min-1) and slow emission (1 mL·min-1) conditions. Furthermore, TOUGHREACT was used to simulate the diagenesis process. A 1D unsteady react-transport model was developed, and the experimental data was used to constrain the simulation. The results of simulation show that the carbonates need 17,000 and 9700 years to grow 1 m under the condition of fast and slow flow scenarios, respectively. The results of this work will contribute to the study of foundation on the formation of authigenic minerals in cold seep areas, and for the physical properties of sedimentary media as well.

ACS Style

Tao Ye; Guangrong Jin; DaiDai Wu; Lihua Liu; Ye; Jin; Wu; Liu; and LiHua Liu. Experimental and Numerical Simulation of the Formation of Cold Seep Carbonates in Marine Sediments. International Journal of Environmental Research and Public Health 2019, 16, 1433 .

AMA Style

Tao Ye, Guangrong Jin, DaiDai Wu, Lihua Liu, Ye, Jin, Wu, Liu, and LiHua Liu. Experimental and Numerical Simulation of the Formation of Cold Seep Carbonates in Marine Sediments. International Journal of Environmental Research and Public Health. 2019; 16 (8):1433.

Chicago/Turabian Style

Tao Ye; Guangrong Jin; DaiDai Wu; Lihua Liu; Ye; Jin; Wu; Liu; and LiHua Liu. 2019. "Experimental and Numerical Simulation of the Formation of Cold Seep Carbonates in Marine Sediments." International Journal of Environmental Research and Public Health 16, no. 8: 1433.

Journal article
Published: 01 February 2017 in Journal of Hazardous Materials
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The disposal of waste cathode ray-tubes (CRTs) from old televisions and discarded computer monitors has become a major environmental concern worldwide. In this work, an open-loop recycling method was developed to synthesize zeolites using CRT funnel glass as the raw material. The effects of hydrothermal temperatures and pressure, n(SiO/AlO) molar ratios and hydrothermal time on the resulting products were investigated. The results indicated that hydrothermal temperatures and pressure played critical roles in zeolite synthesis. Amorphous phases were detected at lower temperatures (80-100°C) and pressure (0.47-1.01bar) with n(SiO/AlO)=2.0. At the temperature of 110°C (pressure 1.43bar), NaA formed with a mixture of NaP1 and Faujasite. With further increase in the temperature and pressure, the unstable NaA and Faujasite disappeared, and Hydroxysodalite developed. The influence of n(SiO/AlO) ratios on resulting products revealed a single phase of NaA was formed at the ratio of 1.5 and a mixture of NaA and Faujasite at the ratio of 2.0. Prolonging hydrothermal time, however, could promote zeolite crystallization, and NaA gradually developed with an increase in the time from 2 to 6h at n(SiO/AlO)=1.5. By comparison, crystallization phases were observed only when the time was longer than 8h at n(SiO/AlO)=2.0.

ACS Style

Zhitong Yao; DaiDai Wu; Jie Liu; Weihong Wu; Hongting Zhao; Junhong Tang. Recycling of typical difficult-to-treat e-waste: Synthesize zeolites from waste cathode-ray-tube funnel glass. Journal of Hazardous Materials 2017, 324, 673 -680.

AMA Style

Zhitong Yao, DaiDai Wu, Jie Liu, Weihong Wu, Hongting Zhao, Junhong Tang. Recycling of typical difficult-to-treat e-waste: Synthesize zeolites from waste cathode-ray-tube funnel glass. Journal of Hazardous Materials. 2017; 324 ():673-680.

Chicago/Turabian Style

Zhitong Yao; DaiDai Wu; Jie Liu; Weihong Wu; Hongting Zhao; Junhong Tang. 2017. "Recycling of typical difficult-to-treat e-waste: Synthesize zeolites from waste cathode-ray-tube funnel glass." Journal of Hazardous Materials 324, no. : 673-680.