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Occurrence of Different Forms and Implications of Compound Specific Sterols in Continental Sediments of the Northeast South China Sea

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Acta Geologica Sinica(English Edition) 2019年第2期93卷 420-429页

作者： QIU Hong ZOU Li ZHANG Minsheng ZHU Chaoqi JIA Yonggang College of Environmental Science and Engineering Ocean University of China Education Key Laboratory fo r Marine Environment and Ecology Ocean University of China The Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of China

The South China Sea(SCS) is one of the most productive and accumulative marginal shelves of organic carbon in the world. To expound the transformation and preservation of organic carbon in the Northeast SCS, where abundant oil and gas resources have been reported, compound specific sterols in free(FR), base hydrolytic(BH), and acid hydrolytic(AH) forms were analyzed in surface and columnar sediments in May, 2016. The results showed that the total contents of sterols detected ranged from 0.15 to 3.74 ppm dry weight in the surface sediments, and gradually decreased from 3.41 to0.17 ppm dry weight from surface to deep sediments, in which cholesterol(27^(△5)) was the most abundant component. Sterols mainly existed in the BH form(54.51%-74.20%), followed by the FR form(25.50%-45.49%) and then the AH form(0-3.77%) in turn, in the surface sediments. BH and FR sterols accounted for 0-49.08% and 50.92%-100% in the columnar sediments, while AH sterols were undetectable. The contents of specific sterols indicated that, the primary source of marine organic carbon was about 5 times as much as that from terrestrial input. More and more FR sterols transformed into BH sterols with increasing sedimentary depth, and BH sterols absolutely dominated in sediment depths under 25 cm. The forms of Sterols C27 were maintained at a relative consistence state, but Sterols C28 to C30 degraded gradually during the sedimentation process. It was suggested that the stability of sterols, based on the chemical structures, might be the primary factor controlling their degradation and preservation in deeper sediments. These results would help to understand the organic carbon(OC) transformation in a hydrate formation area in a marginal sea.

关键词： sterols sediments occurrence forms transformation northeast South China Sea

Marine Geohazards： Review and Future Perspective

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Acta Geologica Sinica(English Edition) 2016年第4期90卷 1455-1470页

作者： JIA Yonggang ZHU Chaoqi LIU Liping WANG Dong Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering (Ocean University of China) Qingdao Shandong 266100 China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology Qingdao Shandong 266061 China Key Laboratory of Marine Environment and Ecology Ministry of Education Ocean University of China Qingdao Shandong 266100 China

With offshore resource exploration moving to the deep water, marine geohazards have been attracting attention from the academic and industry. Research achievements of marine geohazards were reviewed in this paper. We analyzed and discussed typical issues among marine geohazards, including coastal erosion, submarine slope failure, turbidity current and special hazards induced by gas hydrate dissociation, in terms of their definition, distribution, characteristics and case studies. Major international projects on marine geohazards headed by the United States, Europe, Japan and other international organizations are introduced as well. Three marine geohazard survey methods, including geophysical survey, geotechnical exploration and in-situ observation, were summarized with a brief description of each approach, respectively. Especially, the history of marine geohazard researches in China is briefly reviewed, showing the disparity between China and developed countries in the study of marine geohazards narrows gradually. The potential research tendency in future was suggested.

关键词： marine geohazards submarine landslide gas hydrate coastal erosion in-situ observation

The observations of seabed sediment erosion and resuspension processes in the Jiaozhou Bay in China

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Acta Oceanologica Sinica 2017年第11期36卷 79-85页

作者： LIU Xiaolei ZHU Chaoqi ZHENG Jiewen GUO Lei YIN Ping JIA Yonggang Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061 China Key Laboratory of Marine Environmental and Ecology Ministry of EducationOcean University of ChinaQingdao 266100China Qingdao Institute of Marine Geology Chinese Geology ScienceQingdao 266071China

In estuarine and coastal areas, the seabed is in a constant process of dynamic change under marine conditions.Seabed sediment erosion and resuspension are important processes that safely control the geological environment. Field tripod observations conducted in the Jiaozhou Bay in China are reported, to investigate the effects of hydrodynamic conditions on the erosion and resuspension processes of the seabed. The observational results show that the maximum shear stress created by tidal currents can reach 0.35 N/m2, which is higher than the wave-induced shear stress during fair weather conditions. A seabed erosion frequently occurs during the flood tide, whereas a seabed deposition occurs during ebb tide. Waves can produce a bottom shear stress approximately equivalent to that induced by currents when the local wind reaches Force 4 with a speed of 5 m/s.When the wind reaches 7 m/s and the significant wave height reaches 26 cm, waves play a more significant role than currents in the dynamic processes of the seabed sediment resuspension and lead to a high value of turbidity that is approximately two to eight times higher than that in fair weather. These analyses clearly illustrate that periodic current-induced sediment erosion and resuspension are dominant in fair weather, whereas episodic high waves are responsible for significant sediment resuspension. Additional work is needed to establish a more thorough understanding of the mechanisms of sediment dynamics in the Jiaozhou Bay.

关键词： seabed sediment erosion resuspension tripod Jiaozhou Bay

Ultrasensitive methyl salicylate gas sensing determined by Pd-doped SnO_(2)

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Frontiers of Materials Science 2022年第4期16卷 71-79页

作者： chaoqi zhu Xiang LI Xiaoxia WANG Huiyu SU Chaofan MA Xiang GUO Changsheng XIE Dawen ZENG State Key Laboratory of Material Processing and Die&Mould Technology Department of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyXiangyang 441003China

Efficient chemicalwarfare agents(CWAs)detection is required to protect people from the cWAs in war and terrorism.In this work,a Pd-doped SnO_(2)nanoparticles-based gas sensor was developed to detect a nerve agent simulant named methyl salicylate.The sensing measurements of methyl salicylate under different Pd doping amounts found that the 0.5 at.%Pd-doped SnO_(2)exhibited a significant improvement in the detection of methyl salicylate at the ppb(1ppb=10-9)level,and the response value to 160 ppb methyl salicylate is 0.72 at 250℃.Compared with the pure SnO_(2),the response value is increased by 4.5 times,which could be attributed to the influence of the noble metal Pd on the oxygen state and its catalytic effect.In addition,the 0.5at.%Pd-doped SnO_(2)sensor still has an obvious response to 16ppb methyl salicylate with a response value of 0.13,indicating the lower detection limit of the sensor.

关键词： SnO_(2) methyl salicylate gas sensor Pd doping noble metal

Nepheloid layer generation by gas eruption:unexpected experimental results

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Journal of Oceanology and Limnology 2023年第2期41卷 769-777页

作者： chaoqi zhu Sanzhong LI Jiangxin CHEN Dawei WANG Xiaoshuai SONG Zhenghui LI Bo CHEN Hongxian SHAN Yonggang JIA Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Key Lab of Submarine Geosciences and Prospecting TechniquesMinistry of Education(MOE)Ocean University of ChinaQingdao 266100China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China Frontiers Science Center for Deep Ocean Multispheres and Earth System and College of Marine GeosciencesOcean University of ChinaQingdao 266100China Hainan Key Laboratory of Marine Geological Resources and Environment Haikou 570206China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China Key Laboratory of Gas Hydrate Ministry of Natural ResourcesQingdao Institute of Marine GeologyQingdao 266061China Laboratory of Marine Geophysics and Georeource Institute of Deep-Sea Science and EngineeringChinese Academy of SciencesSanya 572000China

Knowledge of nepheloid layers is important to improve the understanding of physical,geological,and sedimentary processes from continental shelf to abyssal environments.We had not tried to study the nepheloid layers in a hydrate-associated tank until unexpected results occurred.Tank experimental results show that gas eruptions triggered intermediate nepheloid layers.Thus,we proposed a new mechanism of intermediate nepheloid layer generation by eruptions.The intermediate nepheloid layers were generated in uniform-density fluid,which indicated that stratified fluid is not a necessary condition for intermediate nepheloid layers.Sufficient space for advection and an oblique slope for detachment are the key ingredients for intermediate nepheloid layer generation by eruptions.Our experiments also offer a new experimental evidence for bottom nepheloid layer generation by earthquakes.Given the scale effects of laboratory experiment,it is important to determine whether submarine volcanic eruption or hydrate-associated venting causes intermediate nepheloid layer in the nature.

关键词： intermediate nepheloid layer gas eruption bottom nepheloid layer gas hydrate tank experiment seafloor instability

Dynamics of Bottom Boundary Layers in the Yellow River Subaqueous Delta Based on Long-Term In-Situ Observations

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Acta Geologica Sinica(English Edition) 2017年第1期91卷 369-370页

作者： ZHU Chaoqi JIA Yonggang WANG Zhenhao GUO Lei SHAN Hongxian LIU Xiaolei ZHANG Minsheng Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering (Ocean University of China) Qingdao 266100 Shandong China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology Qingdao 266061Shandong China

Objective In geo-marine science,the generalized bottom boundary layer（BBL）represents a layer between sediments and seawater.The BBL plays an important role in geological,geobiochemical,geophysical and geotechnical r... 详细信息

关键词： Dynamics of Bottom Boundary Layers in the Yellow River Subaqueous Delta Based on Long-Term In-Situ Observations

Liquid-plastic Limit of Surface Sediments in North Slope of South China Sea

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Acta Geologica Sinica(English Edition) 2017年第S1期91卷 259-260页

作者： JIANG Jun ZHU Chaoqi SHEN Zhicong ZHANG Bowen ZHANG Xiatao WANG Xinquan JIA Yonggang Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering (Ocean University of China) Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology

1 Introduction China has a vast area of continental shelf and is very rich in marine resources,but because of the complex geological environment and frequent geological disasters,the utilization of marine resources an... 详细信息

关键词： soil Liquid-plastic Limit of Surface Sediments in North Slope of South China Sea

Surface Sediment Density and Moisture Content in North slope of South China Sea

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Acta Geologica Sinica(English Edition) 2017年第S1期91卷 155-156页

作者： ZHANG Bowen ZHU Chaoqi JIA Yonggang ZHANG Xiatao DAI Xinnan SHEN Zhicong JIANG Jun WANG Xinquan Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering( Ocean University of China) Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology

Marine engineering geology is mainly based on the actual project to study the seabed.This provides a variety of engineering geological parameters for the development of marine engineering(zhu et al.,2016).This is an e... 详细信息

关键词： Surface Sediment Density and Moisture Content in North slope of South China Sea

Preservation of Lipid Molecular Fossils in the Sediments from an Oil-Gas Releasing Zone in the South China Sea

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Journal of Ocean University of China 2018年第6期17卷 1336-1342页

In order to explore the standing stock and preservation of organic carbon, different forms of compound specific lipids were analyzed, based on a 1.8 m sediment core collected in the northern continental shelf of South China Sea in May, 2016. In the core sediments, 21 species of fatty acids, 6 species of alcohols, 8 species of sterols and phytol were detected. Fatty acids were dominated components with the percent of 67%–91% in the total lipids, in which saturated fatty acid C16:0 accounted for about 50%. The contents of lipid species generally decreased from the sediments at surface to those deep, except alcohols waving in a certain range at the same time. Fatty acids primarily existed in free form, followed by base hydrolytic form, and then acid hydrolytic form. Free alcohols were obviously dominated, while base and acid hydrolytic forms contributed small comparably. Phytol gave a significant priority to base hydrolytic form, while acid hydrolytic form could be neglected. Similar to phytol, sterols mostly presented in base hydrolytic form, and then in free form. The compositions of lipids and their forms suggested that organic carbon basically originated from primary production in upper waters in studying area, and were well preserved in the sediments.

关键词： lipids sediments preservation South China Sea