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Geochemical processes controlling dissolved selenium in the Changjiang(Yangtze) Estuary and its adjacent waters

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Acta Oceanologica Sinica 2014年第10期33卷 19-29页

作者： WU Xiaodan SONG Jinming WU Bin li tiegang li Xuegang Institute of Oceanology Chinese Academy of Sciences University of Chinese Academy of Sciences

Dissolved selenium in the Changjiang（Yangtze） Estuary and its adjacent waters was determined by hydride generation atomic fluorescence spectrometry to elucidate the source, behavior in estuary, adsorption-desorption process and biological role. In surface water, Se（IV） concentration ranged 0.05–1.14 nmol/L and Se（VI） concentration varied 0.01–1.20 nmol/L, with the means of 0.76 and 0.49 nmol/L, respectively. In bottom water, Se（IV） content varied 0.03–0.27 nmol/L and Se（VI） content ranged 0.04–0.85 nmol/L, with the averages of 0.10 and 0.40 nmol/L, respectively. High level of Se（IV） was observed near the shore with a significant decrease towards the open sea, suggesting the continental input from the adjacent rivers. Large value of Se（VI） was found in bottom water, reflecting the release from suspended sediment. Besides, high value appeared in the same latitude of the Changjiang Estuary and Hangzhou Bay illustrated the effect of lateral mixing and the long-distance transport of selenium. Se（VI）, more soluble, occupied higher percentage in aqueous environment. The presence of Se（IV） resulted from the degradation of residue and the reduction of Se（VI） under anaerobic condition. The positive relationship to suspended particulate material（SPM） and negative correlation to depth indicated that Se（IV） tended to be released from the high density particulate matter. Instead, Se（VI） content did not significantly relate to SPM since it generally formed inner-sphere complex to iron hydroxide. Se（IV） content negatively varied to salinity and largely depended on the freshwater dilution and physical mixing. While, Se（VI） level deviated from the dilution line due to the in situ biogeochemical process such as removal via phytoplankton uptake and inputs via organic matter regeneration. As the essential element, Se（IV） was confirmed more bioavailable to phytoplankton growth than Se（VI）, and moreover, seemed to be more related to phosphorus than to nitrogen.

关键词： dissolved selenium distribution geochemical behavior Changjiang(Yangtze) Estuary

The evolution of the Kuroshio Current over the last 5 million years since the Pliocene: Evidence from planktonic foraminiferal faunas

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Science China Earth Sciences 2020年第11期63卷 1714-1729页

作者： Jia WANG Fengming CHANG tiegang li Hanjie SUN Yikun CUI Tianhao liU 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 266061China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of OceanographyMNRQingdao 266061China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

Meridional heat transport of the western Pacific boundary current(the Kuroshio Current)is one of the key factors in global climate *** current is important because it controls the temperature gradient between low latitudes and the North Pacific and so significantly influences mid-latitude atmosphere-ocean *** we reconstruct changes in hydrological conditions within the mid-latitude mainstream of the Kuroshio Current based on faunal analysis of planktonic foraminifera in core DSDP 296 from the Northwest Pacific *** approach enabled us to deduce evolutionary processes within the Kuroshio Current since the Pliocene.A total of 57 species in the coarser section(>150μm)were identified;results indicate that planktonic foraminiferal faunal evolution has mainly been characterized by three major stages,the first of which comprised mixed-layer warm-water species of Globigerinoides ruber which first appeared between 3.5 and 2.7 Ma and then gradually increased in *** of another warm-water species of *** also gradually increased in number over this *** in warm-water species indicate a gradual rise in sea surface temperature(SST)and imply initiation of Kuroshio Current impact on the Northwest Pacific Ocean since at least 3.5 ***,over the period between 2.7 and 2.0 Ma,thermocline species of Globigerina calida,Neogloboquadrina humersa,Neogloboquadrina dutertrei,and Pulleniatina obliquiloculata started to appear in the *** fauna was dominated by *** as well as increasing *** *** features imply a further rise in SST and its gradually enhanced influence on thermocline water,suggesting strengthening of the Kuroshio Current since 2.7 ***,between 2.0 Ma and present,increasing contents of thermocline species(i.e.,***,*** and ***)indicate a gradual rise in seawater temperature at this depth and also imply more intensive Kuroshio Current during th

关键词： Pliocene Kuroshio Planktonic foraminifera Western Pacific Warm Pool

Biocalcification crisis in the continental shelf under ocean acidification

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Geoscience Frontiers 2023年第6期14卷 1-7页

作者： Shuaishuai Dong Yanli Lei tiegang li Yifei Cao Kuidong Xu Laboratory of Marine Organism Taxonomy and Phylogeny Qingdao Key Laboratory of Marine Biodiversity and ConservationInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of OceanographyMNRQingdao 266061China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China University of Chinese Academy of Sciences Beijing 100049China

Ocean acidification(OA)is a persistent challenge for humans and is predicted to have deleterious effects on marine organisms,especially marine calcifiers such as coral and *** foraminifera is an important component of sediment in the continental shelf,while little is known about the impact of ocean acidification on benthic foraminifera both at the community and individual level and associated calcium carbonate *** conducted eight months continued culture experiment under the scenario of 400,800,1200 and 1600 ppm pCO_(2)gradients on living benthic foraminifera from four stations in the continental shelf of the West Pacific *** results showed OA had a negative effect on the abundance of benthic *** contrast,the diversity increased roughly under OA conditions implying OA might stimulate the emergence of rare species and promote community diversity to some *** addition,we confirmed that the offshore area wasn’t the refuge for benthic foraminifera while the nearshore one had more resistance to moderate *** species Protelphidium tuberculatum was the dominant species occupying on average 75%in all treatments and its shell diameter,weight and thickness showed a decrease,indicating the decrease of calcification of benthic foraminifera.A relationship between the weight of *** and pCO_(2)(R^(2)=0.96)was *** on the present work,calcareous benthic foraminifera deposited 8.57104 t calcium carbonate per year and this might reduce by nearly half and 90%under 800 and 1200 ppm scenarios,which indicates a biocalcification crisis under ongoing *** work shows an analogy for palaeoceanic OA and also provides new insights into the sediment of calcium carbonate in the future.

关键词： Benthic foraminifera pCO_(2) Ocean acidification Continental shelf Calcium carbonate deposit Yellow Sea

Testing the mantle plume hypothesis： an IODP effort to drill into the Kamchatka-Okhotsk Sea basement

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Science Bulletin 2017年第21期62卷 1464-1472页

作者： Yaoling Niu Xuefa Shi tiegang li Shiguo Wu Weidong Sun Rixiang Zhu Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China Department of Earth Sciences Durham UniversityDurham DH1 3LEUK lnstitute of Oceanology Chinese Acadermy of SciencesQingdao 266071.China First Institute of Oceanography State Oceanic AdministrationQingdao 266061China Institute of Deep-sea Science and Engineering Chinese Acadery of SciencesSanya 572000China Institute of Geology 8 Geophysics Chinese Academy of SciencesBeijing 100029China

The great mantle plume debate(GPD) has been going on for ~15 years(Foulger and Natland, 2003;Anderson, 2004; Niu, 2005; Davies, 2005; Foulger, 2005; Campbell, 2005; Campbell and Davies, 2006),centered on whether mantle plumes exist as a result of Earth's cooling or whether their existence is purely required for convenience in explaining certain Earth phenomena(Niu, 2005). Despite the mounting evidence that many of the so-called plumes may be localized melting anomalies, the debate is likely to continue. We recognize that the slow progress of the debate results from communication *** debaters may not truly appreciate(1) what the mantle plume hypothesis actually is, and(2) none of the petrological, geochemical and geophysical methods widely used can actually provide smoking-gun evidence for or against mantle plume hypothesis. In this short paper, we clarify these issues, and elaborate a geologically effective approach to test the hypothesis. According to the mantle plume hypothesis, a thermal mantle plume must originate from the thermal boundary layer at the core-mantle boundary(CMB), and a large mantle plume head is required to carry the material from the deep mantle to the surface. The plume head product in ocean basins is the oceanic plateau, which is a lithospheric terrane that is large(1000's km across), thick(>200 km), shallow(2–4 km high above the surrounding seafloors), buoyant(~1% less dense than the surrounding lithosphere), and thus must be preserved in the surface geology(Niu et al., 2003). The Hawaiian volcanism has been considered as the surface expression of a type mantle plume, but it does not seem to have a(known) plume head product. If this is true, the Hawaiian mantle plume in particular and the mantle plume hypothesis in general must be questioned. Therefore, whether there is an oceanic plateau-like product for the Hawaiian volcanism is key to testing the mantle plume hypothesis, and the Kamchatka-Okhotsk Sea basement is the best cand

关键词： Mantle plume debate Geologically testing plume hypothesis Drilling into Kamchatka-Okhotsk Sea basement

Sedimentation rates and provenance analysis in the Southwestern Okinawa Trough since the mid-Holocene

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Chinese Science Bulletin 2009年第7期54卷 1234-1242页

作者： li ChuanShun JIANG Bo li AnChun li tiegang JIANG FuQing Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China Graduate University Chinese Academy of Sciences Beijing 100049 China China Ocean Press Beijing 100081 China

As a high-sedimentation rate depocenter along the path of the Kuroshio Current, the southwesternmost part of the Okinawa Trough is a key area to understand the Kuroshio history and sediments transpor-tation. A 34.17-m-long sediment core was obtained by the advanced piston corer of Marco Polo/IMAGES XII MARION DUFRESNE during the May 2005 from the Southern Okinawa Trough at site MD05-2908. The recovered sediments were analyzed by AMS 14C dating, coarse size fraction (>63 μm) extraction and moisture content determination in order to study its sedimentation flux and provenance. The depth-age relationship of core MD05-2908 was well constrained by 17 14C dating points. The sediments span across the mid-Holocene (6.8 ka B.P.) and have remarkablely high sedimentation rates between 1.8 and 21.2 m ka?1, which is well consistent with the modern observations from sediment traps. We identified five 70―200 a periods of abnormally rapid sedimentation events at 6790―6600 a B.P., 5690―5600 a B.P., 4820―4720 a B.P., 1090―880 a B.P., and 260―190 a B.P., during which the highest sedimentation rate is up to 21.2 m/ka. In general, the lithology of the sediments were dominated by silt and clay, associated with less than 5% coarse size fraction (>63 μm). As the most significant sediment source, the Lanyang River in northeastern Taiwan annually deliver about 10Mt materials to the coastal and offshore region of northeast Taiwan, a portion of which could be carried northward by currents toward the study area. Therefore, we concluded that the 5 abnormally rapid sedimentation events may be related to intensified rainfall in Taiwan and thus increased materials to our study area at that time. However, a few extreme-rapid sedimentation events cannot be explained by normal river runoff alone. The large earth-quakes or typhoons induced hyperpycnal discharge of fluvial sediment to the ocean may also act as a potential source supply to the Okinawa Trough.

关键词：南冲绳海槽沉积速率河流沉积物异常事件中期西南泥沙来源马可波罗

Evolution and variation of the Tsushima warm current during the late Quaternary: Evidence from planktonic foraminifera, oxygen and carbon isotopes

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Science China Earth Sciences 2007年第5期50卷 725-735页

作者： li tiegang SUN RongTao ZHANG DeYu liU ZhenXia li Qing JIANG Bo Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China Graduate School of Chinese Academy of Sciences Beijing 100039China School of Resources&Environment Engineering Shandong University of TechnologyZibo 255049China The First Institute of Oceanography State Oceanic AdministrationQingdao 266003China

The evolution and variation history of the Tsushima warm current during the late Quaternary was reconstructed based on the quantitative census data of planktonic foraminiferal fauna, together with oxygen and carbon isotope records of mixed layer dweller G. ruber and thermocline dweller N. dutertrei in piston core CSH1 and core DGKS9603 collected separately from the Tsushima warm current and the Kuroshio dominated area. The result showed that the Tsushima warm current vanished in the lowstand period during 40―24 cal ka BP, while the Kuroshio still flowed across the Okinawa Trough, arousing strong upwelling in the northern Trough. Meanwhile, the influence of freshwater greatly increased in the northern Okinawa Trough, as the broad East China Sea continental shelf emerged. The freshwater reached its maximum during the last glacial maximum (LGM), when the upwelling obviously weakened for the lowest sea-level and the depression of the Kuroshio. The modern Tsushima warm current began its development since 16 cal ka BP, and the impact of the Kuroshio increased in the middle and north- ern Okinawa Trough synchronously during the deglaciation and gradually evolved as the main water source of the Tsushima current. The modern Tsushima current finally formed at about 8.5 cal ka BP, since then the circulation structure has been relatively stable. The water of the modern Tsushima cur- rent primarily came from the Kuroshio axis. A short-term wiggle of the current occurred at about 3 cal ka BP, probably for the influences from the enhancement of the winter monsoon and the depression of the Kuroshio. The cold water masses greatly strengthened during the wiggle.

关键词： Tsushima warm current Kuroshio late Quaternary planktonic foraminifera oxygen and carbon isotopes Okinawa Trough

Revisiting the dependence of thermocline-dwelling foraminiferal B/Ca on temperature and [CO32-], and its application in reconstruction of the subsurface carbonate system in the tropical western Pacific since 24 ka

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Acta Oceanologica Sinica 2019年第9期38卷 71-86页

作者： Jingteng Guo tiegang li Zhifang Xiong Xiaohua Qiu Fengming Chang CAS Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China First Institute of Oceanography Ministry of Natural Resources Qingdao 266061 China University of Chinese Academy of Sciences Beijing 100049 China Laboratory for Marine Geology and Environment Pilot National Laboratory for Marine Science and Technology (Qingdao) Qingdao 266237 China No. 1 Institute of Geology and Mineral Resources of Shandong Province Jinan 250014 China

The B/Ca ratio of planktonic foraminifer shells has been used as a proxy for reconstructing past ocean carbonate chemistry. However, recent studies have revealed significant uncertainties associated with this proxy, such as whether seawater temperature or [CO^2-3 ] is the dominant control on the partition coefficient (KD) of planktonic foraminiferal B/Ca. To address these uncertainties and thus improve our understanding of the planktonic foraminiferal B/Ca proxy, we analysed B/Ca ratios in the tests of Neogloboquadrina dutertrei (300- 355 μm) and Pulleniatina obliquiloculata (355- 400 μm) in surface sediment samples from the tropical western Pacific and South China Sea. The relationship between these B/Ca ratios and bottom water calcite saturation states (Δ[CO^2-3 ]) is weak, thus suggesting only a small dissolution effect on the B/Ca of the two species. The correlation coefficients (R2) between the B/Ca ratios of N. dutertrei and P. obliquiloculata and environmental parameters (e.g., temperature, salinity, phosphate, DIC and ALK) in the tropical western Pacific and South China Sea are not high enough to justify using B/Ca ratios as a palaeoenvironmental proxy in the study areas. The significant correlation between KD values of N. dutertrei and P. obliquiloculata and carbonate system parameters (e.g.,[CO^2-3 ], DIC, ALK, pH and [HCO^-3 ]) in the study area reflect chemical links between the KD denominator and these variables. Based on our surface sediment calibration, an empirical relationship between the KD of N. dutertrei and temperature is proposed in the tropical western Pacific. We also generated a record of B/Ca ratios in N. dutertrei (300 -355 μm) from Core MD06-3052 in the tropical western Pacific over the past 24 ka to evaluate the application of the revised B/Ca proxy method. Based on the reconstructed empirical relationship for B/Ca and subsurface seawater ALK, we estimated subsurface seawater carbonate system parameters in the tropical western Pacific si

关键词： planktonic foraminifera B/Ca carbonate chemistry tropical western Pacific South China Sea

Paleoenvironment evolution of the East Philippine Sea recorded in the new-type ferromanganese crust since the terminal Late Miocene

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Science China Earth Sciences 2007年第8期50卷 1179-1188页

作者： XU ZhaoKai li AnChun JIANG FuQing li tiegang MENG QingYong JIN Ning Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China Graduate University of Chinese Academy of Sciences Beijing 100039China

From systemic research of microstructure, geochemistry, uranium-series and 10Be isotope dating on a new-type deepwater ferromanganese crust from the East Philippine Sea, the paleoenvironment evolu-tion of the target area since the terminal Late Miocene was recovered. The vertical section changes of microstructure and chemical composition are consistent in the studied crust, which indicate three major accretion periods and corresponding paleoenvironment evolution of the crust. The bottom crust zone was formed in the terminal Late Miocene (5.6 Ma) with loose microstructure, high detritus content and high growth rate. Reductions of mineral element content, accretion rate and positive Ce-anomaly degree at 4.6 Ma indicate temporal warming, which went against the crust accretion and finally formed an accretion gap in the terminal Middle Pliocene (2.8―2.7 Ma). The more active Antarctic bottom sea-waters in the Late Pliocene (2.7 Ma) facilitated the fast transfer to the top pure crust zone. Hereafter, with the further apart of volcanic source and the keeping increase of eolian material (1.0 Ma), although surrounding conditions were still favorable, mineral element content still shows an obvious reducing trend. It thereby offers new carrier and data for the unclear paleoceanographic research of the target area since the terminal Late Miocene.

关键词： new-type ferromanganese crust record paleoenvironment evolution uranium-series dating 10Be isotope dating East Philippine Sea

Vast laminated diatom mat deposits from the west low-latitude Pacific Ocean in the last glacial period

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Chinese Science Bulletin 2009年第23期54卷 4529-4533页

作者： ZHAI Bin li tiegang CHANG FengMing CAO QiYuan Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Diatoms are one of the predominant contributors to global carbon fixation by accounting for over 40% of total oceanic primary production and dominate export production. They play a significant role in marine biogeochemistry cycle. The diatom mat deposits are results of vast diatoms bloom. By analysis of diatom mats in 136°00′―140°00′E,15°00′―21°00′N, Eastern Philippines Sea, we identified the species of the diatoms as giant Ethmodiscus rex (Wallich) Hendey. AMS 14C dating shows that the sediments rich in diatom mats occurred during 16000―28600 a B.P., which means the bloom mainly occurred during the last glacial period, while there are no diatom mat deposits in other layers. Preliminary analysis indicates that Antarctic Intermediate Water (AAIW) expanded northward and brought silicate-rich water into the area, namely, silicon leakage processes caused the bloom of diatoms. In addition, the increase of iron input is one of the main reasons for the diatom bloom.

关键词：末次冰期硅藻藻垫存款太平洋低纬度生物地球化学循环层压