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Application of confocal laser Raman spectroscopy on marine sediment microplastics

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Journal of Oceanology and Limnology 2020年第5期38卷 1502-1516页

作者： LIU Jing ZHANG Xin DU Zengfeng LUAN Zhendong LI Lianfu XI Shichuan WANG Bing CAO Lei YAN Jun key laboratory of marine geology and environment¢er of deep sea research Institute of OceanologyChinese Academy of SciencesQingdao 266071China laboratory for marine geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China University of Chinese Academy of Sciences Beijing 100049China center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

marine sediment is the primary sink of microplastics and is an indicator of pollution ***,although there are well-developed detection methods,detection is rarely focused on lowmicrometer-sized particles,mainly due to technique *** this study,a simplifi ed process omitting digestion procedures was developed to pretreat microplastics obtained from marine sediment and was coupled with micro-Raman spectroscopy to identify *** on the overall analysis of the characteristic peak assignments,a Raman spectral reference library was constructed for 18 types of *** addition,the eff ects of the measurement parameters were systematically *** research was then conducted to validate the developed process and investigate microplastic contamination in Huiquan Bay,Qingdao,*** simplifi ed process could retain the original appearance of microparticles and accomplish the detection ofenvironmental *** in the size range of 10-150μm accounted for 76%of all microplastics,and 56%of the total particles was particles smaller than 50μ***(42%)and polyethylene(20%)were predominant components of the *** particular,polypropylene particles smaller than 10μm were identifi ed in marine *** work demonstrates that Raman spectroscopy is not only an eff ective tool for detecting environmental particles but also highly applicable for identifying particles extracted from marine sediment.

关键词： microplastics confocal Raman spectroscopy marine sediment

Assessment of structural stability in Bohai sea area based on AHP-GDM model

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Acta Oceanologica Sinica 2013年第4期32卷 41-48页

作者： XIU Zongxiang LIU Baohua XIE Qiuhong LI Xishuang LIU Chenguang PEI Yanliang ZHENG Yanpeng The First Institute of Oceanography State Oceanic Administration key laboratory of marine Sedimentology and environmental geology National deep sea center

The AHP-GDM model is used for the assessment of structural stability, with the Bohai sea area as an exam- ple. In this model, the credit degree of each expert is calculated through the assessment matrix based on the similarity and diversity of vector. The comprehensive opinions of expert panel are quantitatively obtained by considering the effect ofcredit degree. According to the geological structural setting, the Bohai sea is di- vided into twelve assessment zones of structural stability by non-uniform element method. The structural stability grade of each zone is obtained on the basis of the latest geophysical data, earthquake statistical data, and the information of fault activities, current stress field and crustal deformation. The results show that there are one relatively stable area, three relatively sub-stable areas, six relatively sub-unstable areas and two relatively unstable areas. The assessment results of non-uniform element method are very close with those of uniform grid method with size of 0.25 in longitude direction and 0.14 in latitude direction. However the workload of non-uniform element method is only 1 / 16 of the latter. Compared with traditional assessment methods of structural stability, a more objective and reliable assessment result can be obtained by combining non-uniform element method and AHP-GDM model.

关键词： AHP-GDM Mode Bohai sea structural stability non-uniform element method

Post-Rifting Magmatism and the Drowned Reefs in the Xisha Archipelago Domain

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Journal of Ocean University of China 2018年第1期17卷 195-208页

作者： WANG Hongli ZHAO Qiang WU Shiguo WANG Dawei WANG Bin key laboratory of marine geology and environment Institute of Oceanology Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences key laboratory of marine Sedimentology and environmental geology First Institute of OceanographySOA laboratory for marine geology Qingdao National Laboratory for Marine Science and Technology laboratory of marine Geophysics and deep-sea Georesources Institute of Deep-Sea Science and Engineering Chinese Academy of Sciences Hangzhou Institute of Petroleum geology PetroChina

Fourteen isolated drowned reefs have been identified around the Xisha Uplift by multibeam and seismic data. The drowning processes of these reefs can be divided into three different stages, which correspond to three different accelerated tectonic subsidence periods. The drowning of the Xisha reefs is the result of the combined action of tectonic subsidence and sea level fluctuations, and the tectonic subsidence rate had to remain above 0.2 mm yr^(-1 )for a long time. Three abrupt accelerated tectonic subsidence events that occurred in the late Miocene, Pliocene and early Quaternary in the Xisha Uplift were closely related to the thermal subsidence processes after three stages of post-rifting magmatism. The magmatism of the middle Miocene and the following thermal subsidence resulted in the drowning of reefs in the northwestern Xisha uplift(Zone A). During the early Pliocene, massive magmatic intrusions and volcanic eruptions occurred in the Xisha Uplift. Then, the subsequent thermal subsidence started the drowning process of reefs in the northeastern and western regions of the Xisha Uplift(Zone B and C). During the early Quaternary, large-scale magmatism also occurred in the Xisha Uplift. The subsequent thermal subsidence resulted in a new rapid tectonic subsidence, which caused the reefs in the southern and southeastern regions of the Xisha Uplift to drown(Zone D and E).

关键词： magmatism tectonic subsidence drowned reef Xisha Archipelago

A Method for Calculating Bottom Backscattering Strength Using Omnidirectional Projector and Omnidirectional Hydrophone

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Journal of Ocean University of China 2019年第2期18卷 358-364页

作者： YU Kaiben YU Shengqi LIU Baohua LIU Zhongchen YANG Zhiguo KAN Guangming ZONG Le College of marine Geo-Sciences Ocean University of China National deep sea center State Oceanic Administration laboratory for marine geology and environment Pilot National Laboratory for Marine Science and Technology (Qingdao) key laboratory of marine Sedimentology and environmental geology First Institute of Oceanography

A method of obtaining bottom backscattering strength by employing an omnidirectional projector and omnidirectional hydrophone is proposed. The backscattering strength is extracted from monostatic backscattering data. The method was adopted in an experiment conducted in the South Yellow sea of China. The seafloor surface was relatively smooth and covered by a small quantity of shell fragments, as observed through a digital camera system. Sampling data showed that the main component of the sediment at this experimental site was fine sand. In this paper, we detail the calculation method. Preliminary results of backscattering strength as a function of grazing angle(20?–70?) in the frequency range of 6–24 kHz are presented. The measured backscattering strength increased with the grazing angle and changed more rapidly at large grazing angles(60?–70?). A comparison of the data at different frequencies reveals that the measured backscattering strength substantially rises with the increase of acoustic frequency. A fitting curve of Lambert's law against the measured data shows that the backscattering strength deviates from Lambert's law at large grazing angles.

关键词： acoustic scattering bottom backscattering strength fine sand Lambert’s law

Acoustic backscattering measurement from sandy seafloor at 6–24 kHz in the South Yellow sea

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Acta Oceanologica Sinica 2019年第5期38卷 99-108页

作者： Guangming Kan Baohua Liu Zhiguo Yang Shengqi Yu Lehua Qi Kaiben Yu Yanliang Pei key laboratory of marine Sedimentology and environmental geology First Institute of Oceanography Ministry of Natural Resources laboratory for marine geology and environment Pilot National Laboratory for Marine Science and Technology(Qingdao) National deep sea center Ministry of Natural Resources College of marine Geosciences Ocean University of China

The acoustic bottom backscattering strength was measured at the frequency range of 6–24 kHz on a typical sandy bottom in the South Yellow sea by using omnidirectional sources and omnidirectional receiving hydrophones. In the experiment, by avoiding disturbances due to scattering off the sea surface and satisfying the far-field condition, we obtained values of acoustic bottom backscattering strength ranging from –41.1 to –24.4 dB within a grazing angle range of 18°–80°. In the effective range of grazing angles, the acoustic scattering strength generally increases with an increase in the grazing angles, but trends of the variation were distinct in different ranges of frequency, which reflect different scattering mechanisms. The frequency dependence of bottom backscattering strength is generally characterized by a positive correlation in the entire frequency range of 6–24 kHz at the grazing angles of 20°, 40° and 60° with the linear regression slopes of 0.222 9 dB/kHz, 0.513 0 dB/kHz and 0.174 6 dB/kHz, respectively. At the largest grazing angle of 80°, the acoustic backscattering strength exhibits no evident frequency dependence.

关键词： acoustic backscattering strength sandy bottom South Yellow sea gazing angle dependence frequency dependence

Automatic calibration for wobble errors in shallow water multibeam bathymetries

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Journal of Oceanology and Limnology 2022年第5期40卷 1937-1949页

作者： Tianyu YUN Xianhai BU Zhe XING Zhendong LUAN Miao FAN Fanlin YANG College of Geodesy and Geomatics Shandong University of Science and TechnologyQingdao 266590China National marine Data and Information Service Tianjin 300012China key laboratory of marine geology and environment¢er of deep sea research Institute of OceanologyChinese Academy of SciencesQingdao 266071China key laboratory of Ocean Geomatics Ministry of Natural ResourcesQingdao 266590China

The wobble errors caused by the imperfect integration of motion sensors and transducers in multibeam echo-sounder systems(MBES)manifest as high-frequency wobbles in swaths and hinder the accurate expression of high-resolution seabed micro-topography under a dynamic marine *** are many types of wobble errors with certain coupling among ***,those current calibration methods ignore the coupling and are mainly manual ***,we proposed an automatic calibration method with the ***,given the independence of the transmitter and the receiver,the traditional georeferenced model is modified to improve the accuracy of footprint ***,based on the improved georeferenced model,the calibration model associated with motion scale,time delay,yaw misalignment,lever arm errors,and soundings is ***,the genetic algorithm(GA)is used to search dynamically for the optimal estimation of the corresponding error parameters to realize the automatic calibration of wobble *** simulated data show that the accuracy of the calibrated data can be controlled within 0.2%of the water *** measured data show that after calibration,the maximum standard deviation of the depth is reduced by about 5.9%,and the mean standard deviation of the depth is reduced by about 11.2%.The proposed method has significance in the precise calibration of dynamic errors in shallow water multibeam bathymetrie s.

关键词： multibeam echo-sounder systems footprint reduction wobble errors genetic algorithm automatic calibration

Geochronological and geochemical constraints on the petrogenesis and geodynamic process of Hemler,Vlinder,and Il'ichev seamount lavas in NW Pacific

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Science China Earth Sciences 2024年第6期67卷 1856-1871页

作者： Xun WEI Yan ZHANG Xuefa SHI Hui ZHANG key laboratory of marine geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China laboratory for marine geology Qingdao Marine Science and Technology CenterQingdao 266237China Shandong key laboratory of deep sea Mineral Resources Development(Preparatory) Qingdao 266061China

Oceanic intraplate volcanoes with linear age progressions are usually accepted to be derived from melting of an upwelling mantle *** seamount groups in NW Pacific,however,show complex age-distance relationships that are difficult to explain using the classic“mantle plume hypothesis”,and thus their origins are *** this study,we present ^(40)Ar-^(39)Ar age,geochemical,and Sr-Nd-Pb-Hf isotopic data of lavas from Hemler,Vlinder,and Il’ichev seamounts in NW Pacific,to elucidate their petrogenesis and geodynamic *** lavas from Hemler,Vlinder,and Il’ichev seamounts are classified as alkali basalt,basanite/nephelinite,and *** with Mg O>8 wt.%exhibit high contents of CaO,FeO^(T),and TiO_(2),similar to the composition of melts formed from reaction between carbonated eclogite-derived melts and fertile *** lavas have elevated Zr/Hf ratios(40.6-45.2)and negative Zr and Hf anomalies,indicating the presence of a carbonate component in the mantle *** are enriched in incompatible trace elements and have enriched mantle 1(EM1)-like SrNd-Pb-Hf isotopic *** isotopic compositions of Vlinder,Il’ichev basanite,and Hemler lavas in this study are similar to the Rarotonga *** occurring at the same seamount,the Il’ichev alkali basalts display more depleted SrNd-Hf isotopic compositions compared to Il’ichev *** to plate tectonic reconstruction results,the ages of Hemler(100.1 Ma),Vlinder pre-(100.2 Ma)and post-shield(87.5 Ma),and Il’ichev(56.4 Ma)lavas clearly deviate from the Macdonald,Arago,Rarotonga,and Samoa hotspot tracks,indicating that they cannot directly originate from mantle *** propose that in the mid-Cretaceous,when the Pacific plate passed over Rarotonga hotspot,melting of Rarotonga plume formed the Vlinder(main-shield stage),Pako,and Ioah *** Rarotonga(and possibly Samoa)plume materials would have been dispersed into the surrounding asthenosphere by mantle conve

关键词： Mantle plume Magellan seamount trail Carbonated mantle component Hotspot Lithosphere extension

Geochemical constraints on CO2-rich mantle source for the Kocebu seamount,Magellan seamount chain in the western Pacific

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Journal of Oceanology and Limnology 2020年第4期38卷 1201-1214页

作者： LIU Yuhao ZHANG Guoliang ZHANG Ji WANG Shuai center of deep sea research&key laboratory of marine geology and environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China laboratory for marine geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266000China University of Chinese Academy of Sciences Beijing 100049China center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

The alkaline oceanic island basalts(OIBs)with under-saturated SiO2 and high contents of CaO and alkaline are usually attributed to mantle sources different from typical tholeiitic *** on the results of high pressure and temperature experiment study,the genesis of silica under-saturated alkaline basaltic melts could be explained by the role of CO2,thus,the genetic relationship of alkaline basalts with CO2 has become a topic of relevance because it is closely related to the deep carbon *** Magellan seamount chain in the West Pacific seamount Province has wide distribution of alkali *** the first time,we collected alkaline basalt samples from the Kocebu seamount of the Magellan seamount chain and found that magmatic apatites widely occur in the less evolved volcanic rock samples,and the high contents of phosphorus should be a feature of the alkaline OIBs of the Magellan *** with typical OIBs,these alkaline volcanic rocks have higher CaO and P2O5,lower SiO2 content,negative anomaly of high field strength elements(HFSEs),more distinctly negative anomaly of potassium(K)and the ubiquity of titanaugite,indicating a CO2-rich mantle *** on the relatively high K2O and TiO2 contents and La/Yb ratio and low MgO content of these alkaline rocks,we suggest that the volcanic rocks of the Magellan seamounts are originated from carbonated eclogites derived possibly from ancient subducted altered oceanic crust.

关键词： alkaline oceanic island basalts(OIBs) carbonatite geochemistry mantle source Magellan seamounts

Formation of the modern current system in the East China sea since the early Holocene and its relationship with sea level and the monsoon system

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Chinese Journal of Oceanology and Limnology 2015年第4期33卷 1062-1071页

作者：郑旭峰李安春万世明蒋富清尹学明卢健 key laboratory of Marginal sea geology South China Sea Institute of Oceanology Chinese Academy of Sciences key laboratory of marine geology and environment Institute of Oceanology Chinese Academy of Sciences University of Chinese Academy of Sciences

The Okinawa Trough is a natural laboratory for the study of air-sea interaction and paleoenvironmental change. It has been demonstrated that present offshore export of particles in the bottom nepheloid layer occur primarily with downwelling from the northeast winter monsoon, which is inhibited by a transverse circulation pattern in summer. This current system was very different during the Last Glacial Maximum owing to low sea level （-120 m） and exposure of a large shelf area. We collected sediment core Oki01 from the middle Okinawa Trough during 2012 using R/V Kexue No. 1 to elucidate the timing and cause of the current system transition in the East China sea. Clay mineral, dry density, and elemental （Ti, Ca） composition of core Oki01 was analyzed. The results indicate that clay minerals derived mainly from the Huanghe （Yellow） and the Changjiang （Yangtze） Rivers during 16.0-11.6 ka, and the modem current system in the East China sea formed beginning in the early Holocene. Therefore, mixing of East China sea continental shelf, Changjiang River and partially Taiwan Island sediment are the major contributors. The decrease of log（Ti/Ca） and alternating provenance since the early Holocene indicate less sediment from the East China in summer because of resistance of the modern current system, i.e., a ＂water barrier＂ and upwelling. Conversely, sediment delivery persists in winter and log（Ti/Ca） indicates the winter monsoon signal since the early Holocene. Our evidence also suggests that sediment from Taiwan Island could be transported by the Kuroshio Current to the middle Okinawa Trough, where it mingles with winter monsoon- induced export of sediment from the Changjiang River and East China sea continental shelf. Although the present research advances understanding of the evolutionary history of paleoenvironmental change in the Okinawa Trough, more sediment cores should be retrieved over wide areas to construct a larger scenario.

关键词： monsoon modem current system Okinawa Trough Kuroshio Current