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Meridional deflection of global eddy propagation derived from tandem altimetry: Mechanism and implication

science China earth sciences 2024年第3期67卷 811-825页

作者： Ge CHEN Xiaoyan CHEN frontiers science center for deep ocean multispheres and earth system School of Marine TechnologyOcean University of ChinaQindao 266100China Laboratory for Regional oceanography and Numerical Modeling Laoshan LaboratoryQindao 266237China

A common view on meridional deflection of eddy propagation is poleward for cyclones and equatorward for anticyclones. This widely accepted polarity-sensitive pattern has been increasingly undermined given that it is systematically violated on both zonal and regional scales as recently reported. Here, we approach the problem by exploring these violations in terms of eddy effects of spatiotemporal geostrophy, thermal fading, and flow dragging, yielding the following main conclusions.(1) The polarity-dependent deflection discrepancy is a pseudo feature resulting from a biased fit to the normalized eddy tracks which are spatially asymmetric(though azimuthally symmetric) between the two signs;Instead, the primary pattern of eddy deflection appears to be geographically correlated and polarity independent.(2) Geostrophic adjustment plays a critical role in defining the meridional movement of an eddy. Specifically, a consistent poleward(equatorward) trajectory bending of spatially(temporally) ageostrophic eddies is observed irrespective of their polarity.(3) The mechanism of eddy deflection is also determined by its zonal propagation direction. Westward propagating eddies are substantially affected by thermal fading, while opposite ones by flow dragging. A realistic and comprehensive understanding of eddy deflection mechanisms serves as a significant contribution to the prediction of eddy trajectory, and the protection of ocean environment.

关键词： Mesoscale eddies Eddy propagation Eddy meridional deflection Satellite observation Geostrophic adjustment

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Effects of ocean Acidification on Nitrogen Metabolism of Skeletonema costatum

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Journal of ocean University of China 2024年第5期23卷 1359-1370页

作者： WANG Shuxing MI Tiezhu ZHEN Yu ZHU Jianbin Key Laboratory of Marine Environment and Ecology Ministry of Education College of Environmental Science and Engineering Ocean University of China Laboratory for Marine Ecology and Environmental science Qingdao Marine Science and Technology Center frontiers science center for deep ocean multispheres and earth system Ocean University of China

ocean acidification（OA）, caused by the rising concentration of atmospheric CO2, leads to changes in the marine carbonate system. This, in turn, affects the physiological processes of phytoplankton. In response to increased p CO2levels, marine microalgae modulate their physiological responses to meet their energy and metabolic requirements. Nitrogen metabolism is a critical metabolic pathway, directly affecting the growth and reproductive capacity of marine microorganisms. Understanding the molecular mechanisms that regulate nitrogen metabolism in microalgae under OA conditions is therefore crucial. This study aimed to investigate how OA affects the expression profiles of key genes in the nitrogen metabolic pathway of the marine diatom Skeletonema costatum. Our findings indicate that OA upregulates key genes involved in the nitrogen metabolic pathway, specifically those related to nitrate assimilation and glutamate metabolism. Moreover, p CO2has been identified as the predominant factor affecting the expression of these genes, with a more significant impact than pH variations in S. costatum. This research not only advances our understanding of the adaptive mechanisms of S. costatum in response to OA but also provides essential data for predicting the ecological consequences of OA on marine diatoms.

关键词： gene expression nitrogen metabolism ocean acidification Skeletonema costatum transcriptome

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Photochemical Production of Methyl Halides with Guaiacol as the Precursor

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Journal of ocean University of China 2024年第5期23卷 1275-1286页

作者： YANG Fan ZHANG Yan WU Guanyu HE Zhen YANG Guipeng frontiers science center for deep ocean multispheres and earth system Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China Laboratory for Marine Ecology and Environmental science Qingdao Marine Science and Technology Center Institute of Marine Chemistry Ocean University of China

Methyl halides are crucial trace greenhouse gases in the atmosphere, playing a significant role in global climate change and the atmospheric environment. This study investigated the photochemical production of methyl halides in an artificial seawater system using guaiacol as a precursor through laboratory simulation experiments. The influences of various environmental factors, including illumination time, radiation wavebands, illumination intensity, concentrations of guaiacol and halide ions（X-）, Fe3+, salinity, dissolved oxygen（DO）, and pH value on the photochemical production of methyl halides were examined. We demonstrated that increased illumination intensity and duration promote the photochemical production of methyl halides, with a notable enhancement under UV-B radiation. Guaiacol and halide ions were identified as key precursors, and their high concentrations facilitated the formation of methyl halides. Additionally, different types of halide ions exhibited a competitive relationship in producing methyl halides. The study found that an increase in pH inhibited the photochemical formation of CH3I due to the reaction between OH-and ·CH3. Dissolved oxygen was found to inhibit the photochemical formation of CH3I while promoting the formation of CH3Cl. Conversely, an appropriate concentration of Fe3+enhanced the photochemical production of methyl halides. Field observations indicated a high photochemical production of methyl halides in the natural waters near Qingdao's coastal area, likely due to the high concentration of dissolved organic matter（DOM）, which supports photochemical reactions. Furthermore, the photochemical production of methyl halides in natural seawater was significantly higher than in dark conditions, underscoring the importance of illumination in promoting these photochemical processes in seawater.

关键词： dissolved organic matter guaiacol methyl halides photochemical production

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Characterization of a Novel Esterase Belonging to Family V from Marinobacter flavimaris

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Journal of ocean University of China 2024年第1期23卷 221-232页

作者： HE Jingjing ZHANG Yunhui WU Leilei WANG Yaru ZHANG He LIU Zhengang SHI Xiaochong frontiers science center for deep ocean multispheres and earth system and College of Marine Life SciencesOcean University of ChinaQingdao 266003China Laboratory for Marine Ecology and Environmental science Laoshan LaboratoryQingdao 266237China Institute of Evolution&Marine Biodiversity Ocean University of ChinaQingdao 266003China

Lipolytic enzymes have attracted enormous attentions because of their ability in ester hydrolysis,ester synthesis,transesterification and other biochemical *** are important sources of lipolytic enzymes applied in ***,a novel lipolytic enzyme encoded by esterase gene est1347 was identified in Marinobacter flavimaris WLL162,and was purified and *** lipolytic enzyme Est1347 consisted of 312 amino acid residues and a 21-amino-acids N-terminal signal peptide with a predicted molecular weight of 34.2 *** belongs to family V of bacterial lipolytic enzymes based on the amino acid sequence homology ***1347 is a mesophilic and alkali-resistant enzyme with the highest activity at 45℃and pH 8.5;it is stable at temperatures below 50℃and pH 7.5–***1347 showed a preference for middle-length chain substrate p-NPC10 and a wide range of other *** Km,Vmax,Kcat and Kcat/Km values of Est1347 for p-NPC10 in pH 8.5 at 45℃were 0.9411 mmol L^(−1),1285μmol min^(−1)mg^(−1),698.91 s^(−1)and 743.65 s^(−1)(mmol L^(−1))^(−1),*** is also tolerant to the metal ions,organic solvents and *** conclusion,the esterase Est1347 laid a foundation for further study of bacterial lipolytic enzyme family V.

关键词： esterase Marinobacter flavimaris enzymatic properties lipolytic enzyme family V

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Effect of dissolved organic nitrogen on the bloom of Prorocentrum donghaiense and Karenia spp. in the East China Sea coastal waters

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Acta oceanologica Sinica 2024年第6期43卷 71-85页

作者： Xiaoru Cui Guangming Zhen Jing Zhao Keqiang Li Xiulin Wang Key Laboratory of Marine Chemistry Theory and Technology/frontiers science center for deep ocean multispheres and earth system of Ministry of Education Ocean University of ChinaQingdao 266100China College of Environmental science and Engineering Ocean University of ChinaQingdao 266100China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China

Understan ding the mechanism of harmful algal bloom formation is vital for effectively preventing algal bloom outbreaks in coastal *** *** in the East China Sea show a significant correlation with nutrient ***,the impact of key components of nutrients,especially dissolved organic nitrogen(DON),on the blooms of Karenia *** not *** research is still *** this study,the cruise observations,field mesocosm-flask culture experiments,and a multinitrogen-tri-phytoplankton-detritus model(NTPD) are combined to reveal the quantitative influence of nutrient regimes on the shift of Prorocentrum donghaiense and Karenia *** the East China *** has a synchronism rhythm of *** spp.-diatom loop in the field culture experiment,which is consistent with the results of the cruise *** results showed that the processes of terrigenous DON(TeDON) and dissolved inorganic nitrogen(DIN:NO_(3)^(-)-N,NH_(4)^(+)-N) absorption promoted *** to become the dominant algae in the community;whereas the processes of DON from *** absorption promoted Karenia *** become the dominant algae in ambient DIN *** addition,the three-dimensional fluorescence components of humus C,tyrosine and fulvic acid can indicate the processes of growth and extinction of *** and Karenia spp.,*** study infers that *** and Karenia *** shift mechanism associated with the nutrient regime in coastal waters,which provides a scientific basis for the environmental management of coastal eco system health.

关键词： Karenia spp. Prorocentrum donghaiense nutrients multinitrogen-tri-phytoplankton-detritus model three-dimensional fluorescence

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Hydrographic Characteristics and oceanic Heat Flux in the Upper Arctic ocean over the Alpha Ridge Observed by the DTOP Platform in 2018 and 2021

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Journal of ocean University of China 2024年第2期23卷 304-316页

作者： WANG Yongjun LI Tao College of oceanic and Atmospheric sciences Ocean University of ChinaQingdao 266100China Frontier science center for deep ocean multispheres and earth system(FDOMES) and Physical oceanography Laboratory Ocean University of ChinaQingdao 266100China Laoshan Laboratory Qingdao 266237China

In 2018 and 2021,the Drift-Towing ocean Profilers(DTOP)provided extensive temperature and salinity data on the upper 120m ocean through their drifts over the Alpha Ridge north of the Canada *** thickness and temperature maximum of Alaska Coastal Water(ACW)ranged from 20m to 40m and-1.5℃to-0.8℃,respectively,and the salinity generally maintained from 30.2 to *** with World ocean Atlas 2018’s climatology manifested a 40m-thick and warm ACW roughly ex-ceeding the temperature maximum by 0.4–0.5℃in June–August *** anomalously warm ACW was highly related to the ex-pansion of the Beaufort Gyre in the negative Arctic Oscillation *** summer,the under-ice oceanic heat flux F_(w)^(OHF)was elevated,with a maximum value of above 25Wm^(-2).F_(w)^(OHF)was typically low in the freezing season,with an average value of 1.2Wm^(-2).The estimates of upward heat flux contributed by ACW to the sea ice bottom F_(w)^(OHF)were in the range of 3–4Wm^(-2)in June–August 2021,when ACW contained a heat content of more than 80MJm^(-2).The heat loss over this period was driven by a weak stratification upon the ACW layer associated with a surface mixed layer(SML)approaching the ACW *** autumn,F_(w)^(OHF)was reduced(<2 Wm^(-2))except during rare events when it elevated F_(w)^(OHF)*** addition,the intensive and widespread Ekman suction,which created a violent upwelling north of the Canada Basin,was largely responsible for the substantial cooling and thinning of the ACW layer in the summer of 2021.

关键词： Arctic ocean oceanic heat flux Alaska Coastal Water Alpha Ridge

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Boosting spring runoff into the sea by reservoir regulation and its potential for estuarine fishery recovery

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science China earth sciences 2024年第5期67卷 1591-1603页

作者： Xiao WU Houjie WANG Yongyong FAN Naishuang BI Chiyuan MIAO Jingping XU Zuosheng YANG College of Marine Geosciences Key Laboratory of Submarine Geosciences and Prospecting Technologyand Frontiers Science Center for Deep Ocean Multispheres and Earth SystemOcean University of ChinaQingdao 266100China Laoshan National Laboratory Qingdao 266061China Institute of the Yellow River Estuary and Coast science Dongying 257000China State Key Laboratory of earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Department of ocean science&Engineering Southern University of Science and TechnologyShenzhen 518055China

With global surge in reservoir construction over the past decades,river systems worldwide have been profoundly ***,flow manipulation by reservoirs has altered the natural hydrological processes,resulting in extensive modifications of fluvial-marine *** the adverse ecological consequences of reservoirs has become a global concern and has garnered increasing *** Yellow River,as one of the most extensively manipulated river systems globally,has experienced substantial changes in the amount and timing of water discharge due to the presence of numerous reservoirs scattered throughout its catchment *** alterations have caused physicochemical changes in the estuary and subsequent modifications to the estuarine *** recent years,the Yellow River Conservancy Committee initiated the release of water through the Xiaolangdi Dam during the major spawning period of fisheries,specifically in the spring,with the aim of improving the estuarine ecological *** 2011 to 2020,a total of 84.05 km^(3)of water was discharged from the Xiaolangdi Reservoir during spring seasons,of which 40%(33.16 km^(3))constituted water impounded within the reservoir during preceding ***,the spring water discharge from the Yellow River to the sea increased significantly from 1.50 km^(3)/yr to 3.46 km^(3)/yr in the past decade,leading to a decrease in estuarine salinity by 1.6 *** estuarine fishery resources,such as fish eggs in the Yellow River estuary,have demonstrated evident *** reservoir regulation in the Yellow River,which has successfully enhanced spring water discharge and subsequently restored estuarine fishery resources,presents an effective attempt for mitigating the adverse ecological effects associated with reservoirs.

关键词： Reservoir regulation Water release Spring runoff Estuarine ecosystem Yellow River

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Asexual Reproduction of Aurelia coerulea Polyps in situ on Settling Plates in Jiaozhou Bay, China

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Journal of ocean University of China 2024年第5期23卷 1371-1380页

作者： MI Tiezhu ZHU Jianbin ZHEN Yu WANG Guoshan WANG Jianyan Key Laboratory of Marine Environment and Ecology Ministry of Education College of Environmental Science and Engineering Ocean University of China Laboratory for Marine Ecology and Environmental science Qingdao Marine Science and Technology Center frontiers science center for deep ocean multispheres and earth system Ocean University of China National Marine Hazard Mitigation Service Ministry of Natural Resources Department of Life sciences National Natural History Museum of China

Jellyfish blooms are increasingly prevalent coastal phenomena, with Aurelia coerulea being a significant contributor. The complex life history of jellyfish, featuring a sessile polyp stage, is a key factor in bloom formation, yet it is challenging to study in the field. This study aimed to describe the asexual reproduction of A. coerulea polyps in Jiaozhou Bay, China, and to assess their ability to form sedentary colonies and their relationship with environmental factors. Using settling plates, we observed polyps in situ and documented three asexual reproduction modes: budding, strobilation, and podocyst formation. Environmental parameters including temperature, salinity, dissolved oxygen(DO), chlorophyll a(Chl a), and the biomass of phytoplankton and zooplankton were monitored. Budding was the predominant reproductive method, featuring stolon budding in autumn and direct budding during the winter and spring seasons. Strobilation took place in the colder months, releasing ephyrae between April and May. Polyp abundance was positively correlated with seawater temperature and negatively correlated with DO concentration. Polyps at 1.0 m depth showed higher survivorship and proliferation over 8 months, whereas those at 2.0 m depth experienced a steady decline and died within 4 months. The study enhances our understanding of the life cycle and asexual reproduction strategies of A. coerulea polyps in the field, with implications for predicting and managing jellyfish blooms. The findings underscore the importance of temperature and DO in polyp survival and suggest that initial polyp population proliferation is crucial for long-term survival.

关键词： asexual reproduction budding jellyfish bloom polyps strobilation

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Microbial Sulfate Reduction and Its Role in Carbon Sequestration in Marine Sediments

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Journal of earth science 2024年第4期35卷 1378-1381页

作者： Xiting Liu Houjie Wang Jiarui Liu Guang-Chao Zhuang Key Laboratory of Submarine Geosciences and Prospecting Technology College of Marine GeosciencesOcean University of ChinaQingdao266100China Qingdao Marine science and Technology center Laboratory for Marine GeologyQingdao266237China Department of earth Planetaryand Space SciencesUniversity of CaliforniaLos Angeles90095USA frontiers science center for deep ocean multispheres and earth system(FDOMES)and Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationOcean University of ChinaQingdao266100China

0 INTRODUCTION The carbon buried in marine sediments in the form of organic carbon or carbonate minerals represents the largest pathway for carbon removal from earth's surface environments(Sun and Turchyn,2014).Microbial sulfate reduction(MSR)is a fundamental biogeochemical process occurring in marine sediments,where sulfate-reducing bacteria(SRB)reduce sulfate(SO42-)to sulfide(S2-)using organic matter or methane as electron donors(Jorgensen,2021).

关键词： buried carbonate environments

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Constraints on Characteristics and Distribution of Gas Hydrate and Free Gas Using Broad-Band Processing of Three-Dimensional Seismic Data

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Journal of ocean University of China 2024年第5期23卷 1233-1247页

作者： WANG Xiujuan ZHOU Jilin LI Sanzhong LI Lixia LI Jie LI Yuanping WANG Linfei SU Pibo JIN Jiapeng GONG Zhi State Key Laboratory of Offshore Natural Gas Hydrate frontiers science center for deep ocean multispheres and earth system Key Laboratory of Submarine Geosciences and Prospecting Techniques MOE and College of Marine Geosciences Ocean University of China Laboratory for Marine Mineral Resources Qingdao Marine Science and Technology Center CNOOC Research Institute Co. Ltd. CNOOC China Limited Shenzhen Branch Guangzhou Marine Geological Survey China Geological Survey

Gas hydrate drilling expeditions in the Pearl River Mouth Basin, South China Sea, have identified concentrated gas hydrates with variable thickness. Moreover, free gas and the coexistence of gas hydrate and free gas have been confirmed by logging, coring, and production tests in the foraminifera-rich silty sediments with complex bottom-simulating reflectors(BSRs). The broad-band processing is conducted on conventional three-dimensional(3D) seismic data to improve the image and detection accuracy of gas hydratebearing layers and delineate the saturation and thickness of gas hydrate-and free gas-bearing sediments. Several geophysical attributes extracted along the base of the gas hydrate stability zone are used to demonstrate the variable distribution and the controlling factors for the differential enrichment of gas hydrate. The inverted gas hydrate saturation at the production zone is over 40% with a thickness of 90 m, showing the interbedded distribution with different boundaries between gas hydrate-and free gas-bearing layers. However, the gas hydrate saturation value at the adjacent canyon is 70%, with 30-m-thick patches and linear features. The lithological and fault controls on gas hydrate and free gas distributions are demonstrated by tracing each gas hydrate-bearing layer. Moreover, the BSR depths based on broad-band reprocessed 3D seismic data not only exhibit variations due to small-scale topographic changes caused by seafloor sedimentation and erosion but also show the upward shift of BSR and the blocky distribution of the coexistence of gas hydrate and free gas in the Pearl River Mouth Basin.

关键词： broad-band processing free gas gas hydrate shift of BSR

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