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Different vertical distribution of zooplankton community between North Pacific Subtropical Gyre and Western Pacific Warm Pool: its implication to carbon flux 预览
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作者 Dong Sun Dongsheng Zhang +1 位作者 Ruiyan Zhang Chunsheng Wang 《海洋学报:英文版》 SCIE CAS CSCD 2019年第6期32-45,共14页
The mesozooplankton in both epipelagic and mesopelagic zones is essentially important for the study of ecosystem and biological carbon pump. Previous studies showed that the diel vertical migration (DVM) pattern of me... The mesozooplankton in both epipelagic and mesopelagic zones is essentially important for the study of ecosystem and biological carbon pump. Previous studies showed that the diel vertical migration (DVM) pattern of mesozooplankton varied among ecosystems. However, that pattern was largely unknown in the Western Pacific Warm Pool (WPWP). The vertical distribution, DVM and community structure of mesozooplankton from the surface to 1 000 m were compared at Stas JL7K (WPWP) and MA (North Pacific Subtropical Gyre, NPSG). Two sites showed similarly low biomass in both epipelagic and mesopelagic zones, which were in accordance with oligotrophic conditions of these two ecosystems. Stronger DVM (night/day ratio) was found at JL7K (1.31) than that at MA (1.09) on surface 0–100 m, and an obvious night increase of mesopelagic biomass was observed at JL7K, which was probably due to migrators from bathypelagic zone. Active carbon flux by DVM of zooplankton was estimated to be 0.23 mmol/(m2·d) at JL7K and 0.16 mmol/(m2·d) at MA. The community structure analysis showed that calanoid copepods, cnidarians and appendicularians were the main contributors to DVM of mesozooplankton at both sites. We also compared the present result with previous studies of the two ecosystems, and suggested that the DVM of mesozooplankton was more homogeneous within the WPWP and more variable within the NPSG, though both ecosystems showed typically extremely oligotrophic conditions. The different diel vertical migration strength of mesozooplankton between NPSG and WPWP implied different efficiency of carbon pump in these two ecosystems. 展开更多
关键词 mesopelagic zone DIEL VERTICAL MIGRATION biological PUMP VERTICAL distribution active carbon FLUX
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Bedrock samples from the Chukchi Borderland,Arctic Ocean—First Chinese dredge in the polar regions 预览
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作者 Tao Zhang Yanhui Dong +2 位作者 Chunguo Yang Qingsheng Guan Jinyao Gao 《海洋学报:英文版》 SCIE CAS CSCD 2019年第11期162-164,共3页
The Chukchi Borderland is a relict continental block in the Arctic Ocean.Its origin and tectonic processes are of great significance for understanding the formation model of the Amerasia Basin and the configurations o... The Chukchi Borderland is a relict continental block in the Arctic Ocean.Its origin and tectonic processes are of great significance for understanding the formation model of the Amerasia Basin and the configurations of the Mesozoic Arctic regions.Due to the harsh environment and rare geological and geophysical data,the evolution of the Chukchi Borderland is still unclear(e.g.,Grantz et al.,1998,2011).We conducted two rock dredges and a multibeam full coverage survey of 830 km2 in the Northwind Abyssal Plain of the Chukchi Borderland during the Chinese ninth Arctic scientific expedition in 2018.This is the first rock dredge survey of China in the polar regions with floating ice,and is just after the HLY0905 dredge at the Northwind Abyssal Plain in 2009(Mayer and Armstrong,2011).The retrieved samples will provide new information for understanding the origin and tectonic evolution of the Chukchi Borderland. 展开更多
关键词 ARCTIC rock TECTONIC
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Harnessing structural instability for cell durotaxis 预览
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作者 Jie Wei Xiaofeng Chen Bin Chen 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第2期355-364,共10页
Cells were suggested to sense matrix rigidity by applying fluctuating forces, but the underlying mechanism remains elusive. Here with a generic filament-crosslinker modeling system for stress fibers, we demonstrate th... Cells were suggested to sense matrix rigidity by applying fluctuating forces, but the underlying mechanism remains elusive. Here with a generic filament-crosslinker modeling system for stress fibers, we demonstrate that high mechanical forces can be induced by specific protein-protein interactions with biased kinetics. Strikingly, we further find that there exist two patterns of force generation, a stable pattern and a fluctuated pattern, in agreement with previous experimental observations. Our analysis indicates that the fluctuated force profile is essentially due to force-induced structural instability during structural assembly. We suggest that how cells utilize or circumvent such stable forces or fluctuated forces may be important in other biological processes as well, though whether such forces should be regarded as passive or active is still tentative. 展开更多
关键词 PROTEIN-PROTEIN interaction Biased KINETICS FORCE GENERATION STABLE PATTERN Fluctuated PATTERN
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Geochemistry and age of seamounts in the West Pacific: mantle processes and petrogenetic implications 预览
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作者 Limei Tang Yanhui Dong +3 位作者 Fengyou Chu Ling Chen Weilin Ma Yonggang Liu 《海洋学报:英文版》 SCIE CAS CSCD 2019年第1期71-77,共7页
Research on seamounts provides some of the best constraints for understanding intraplate volcanism, and samples from seamounts reveal crucial evidence about the geochemical makeup of the oceanic mantle. There are stil... Research on seamounts provides some of the best constraints for understanding intraplate volcanism, and samples from seamounts reveal crucial evidence about the geochemical makeup of the oceanic mantle. There are still many seamounts in the West Pacific Seamount Province (WPSP) that have not been studied, meaning their ages and geochemistry remain unknown. A better understanding of these seamount trails and their evolutionary history, investigated with age and geochemistry data, will enable better understanding of the geological processes operating underneath the Pacific Ocean Plate. Here, new ^40Ar/^39Ar ages and trace element and Sr-Nd-Pb isotopic data for seven basalt rocks from four seamounts in the WPSP are provided. Chemically, these rocks are all Oceanic Island Alkali basalt (OIA type);analysis of olivine phenocrysts shows that the magmas experienced strong olivine fractionation and changed from olivine + plagioclase to olivine + plagioclase + clinopyroxene cotectic during their evolution. Rare earth element (REE) patterns and a spider diagram of the samples in this study show OIB (Ocean Island Basalt) like behavior. The range of ^87Sr/^86Sr values is from 0.704 60 to 0.706 24, the range of ^206Pb/^204Pb values is from 18.241 to 18.599, and the range of ^143Nd/^144Nd values is from 0.512 646 to 0.512 826;together, these values indicate magma sources ranging from EMI to EMII. Finally, new ^40Ar/^39Ar age data show that these seamounts formed at ~97 and ~106 Ma, indicating that some may have undergone the same formation processes as seamounts in the eastern part of the Magellan Seamount Trail, but other seamounts likely have different origins. 展开更多
关键词 ^40AR/^39AR ages GEOCHEMISTRY magmatic evolution BASALTS West PACIFIC
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微小RNA-451对巨噬细胞移动抑制因子的调控及对结肠癌细胞增殖与迁移的影响
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作者 李国梁 潘志坚 +1 位作者 柴立新 邓国华 《中华实验外科杂志》 CAS CSCD 北大核心 2019年第11期2026-2028,共3页
目的观察miR-451对巨噬细胞移动抑制因子(MIF)的调控及对结肠癌细胞增殖与迁移的影响。方法脂质体Lipofectamine™3000将miR-451 mimics和miR-451 NC转入SW480结肠癌细胞中,实时定量聚合酶链反应(Real-time PCR)检测miR-451表达,噻唑蓝(M... 目的观察miR-451对巨噬细胞移动抑制因子(MIF)的调控及对结肠癌细胞增殖与迁移的影响。方法脂质体Lipofectamine™3000将miR-451 mimics和miR-451 NC转入SW480结肠癌细胞中,实时定量聚合酶链反应(Real-time PCR)检测miR-451表达,噻唑蓝(MTT)法检测细胞活力,细胞克隆形成实验检测细胞克隆能力,流式细胞术检测细胞周期,Transwell实验检测细胞迁移能力,Real-time PCR法及蛋白质印迹法(Western blot)检测细胞中MIF蛋白及mRNA表达,并进行荧光素酶报告基因分析。结果miR-451 mimics组(2.46±0.25)中miR-451表达量高于miR-451 NC组(1.00±0.11,t=52.374,P<0.05)。miR-451 mimics组(0.37±0.03)细胞活力低于miR-451 NC组(0.58±0.06,t=30.672,P<0.05)。miR-451 mimics组(41.56±4.17)细胞克隆数目少于miR-451 NC组(132.37±11.29,t=73.927,P<0.05)。miR-451 mimics组G1期长于miR-451 NC组(t=4.093,P<0.05),miR-451 mimics组G2期短于miR-451 NC组(t=6.349,P<0.05)。miR-451 mimics组[(56.59±5.66)个]细胞迁移袭数目少于miR-451 NC组[(184.73±18.47)个,t=64.992,P<0.05]。miR-451 mimics+pGL4 MIF 3’端非编码区(3’UTR)-Wt组的荧光强度低于其它所有转染组(F=2875.12,P<0.05)。miR-451 mimics组(0.35±0.03)中MIF mRNA表达量低于与miR-451 NC组(1.00±0.10)(t=61.001,P<0.05)。Western blot实验结果表明,miR-451 mimics组(0.23±0.02)中MIF蛋白表达量低于miR-451 NC组(0.92±0.10)(t=66.293,P<0.05)。结论miR-451表达量上调后能够通过负性调控MIF表达,抑制SW480细胞增殖与迁移。 展开更多
关键词 结肠癌 微小RNA-451 巨噬细胞移动抑制因子 增殖 侵袭
The spatial distribution of major and trace elements of surface sediments in the northeastern Beibu Gulf of the South China Sea 预览
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作者 Qian Ge George Z Xue +3 位作者 Liming Ye Dong Xu Jianru Zhao Fengyou Chu 《海洋学报:英文版》 SCIE CAS CSCD 2019年第3期93-102,共10页
A multi-index analysis including grain size, major and trace elements is performed on the surface sediments from the northeastern Beibu Gulf to trace the sources of the sediments and to understand the controlling fact... A multi-index analysis including grain size, major and trace elements is performed on the surface sediments from the northeastern Beibu Gulf to trace the sources of the sediments and to understand the controlling factors for elements distribution. The mean grain size exhibits a wide variation ranging from 0.09Φ to 8.05Φ with an average value of 5.33Φ. The average contents of major elements descend in an order of c(SiO2)>c(Al2O3)>c(Fe2O3)>c(CaO)>c(MgO)>c(K2O)>c(Na2O)>c(TiO2)>c(P2O5)>c(MnO), while those of trace elements exhibit a descending order of c(Sr)>c(Rb)>c(V)>c(Zn)>c(Cr)>c(Pb)>c(Ni)>c(Cu)>c(As). On the basis of elementary distribution characteristics and statistical analyses, the study area is divided into the four zones: Zone I is located in the northeastern coastal area of the gulf, which receives large amount of fluvial materials from local rivers in Guangxi and Guangdong, China, and the Qiongzhou Strait;Zone Ⅱ is located in the center of the study area, where surface sediments exhibits a multiple source;Zone Ⅲ is located in the Qiongzhou Strait, where surface sediments are dominated by materials from the Zhujiang River and Hainan;Zone IV is located in the southwest of the study area, where surface sediments are mainly originated from the Red River and Hainan. The statistical analyses of sediment geochemical characteristics reveal that the grain size, which is mainly influenced by hydrodynamics and mineral composition of terrigenous materials, is the leading factor controlling the elementary distribution.Meanwhile, impacts from anthropogenic activities and marine biogenic process will also be taken into consideration. 展开更多
关键词 GRAIN size major and TRACE elements Beibu GULF spatial distribution sediment source
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Geochemical Characteristics of Saturated Hydrocarbons from Strata Inferred from the Multitubular Cores of the Prydz Bay and the Sources/Environmental Variations 预览
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作者 Yang Dan Zhang Yicheng +4 位作者 Han Xinbin Zhao Jun Xu Xuedan Zhang Huijuan Zhang Haisheng 《气象与环境研究:英文版》 CAS 2019年第5期96-102,共7页
The content and distribution of saturated hydrocarbons (n-alkanes,isoprenoid,steranes and terpanes) in the multitubular cores ANT29-M2 from the Prydz Bay of the Antarctic were analyzed using gas chromatography-mass sp... The content and distribution of saturated hydrocarbons (n-alkanes,isoprenoid,steranes and terpanes) in the multitubular cores ANT29-M2 from the Prydz Bay of the Antarctic were analyzed using gas chromatography-mass spectrometry,and the organic matter sources,sedimentary environments and geochemical parameters of the sediments were discussed.The results showed that the carbon number of the multitubular samples ANT29-M2 was between C14 and C32 with low-carbon single peak group and main peak carbon of C18 .n-alkane gas charomatography fingerprint spectra indicated that unmixable complex compounds displayed a significant bulge,and the obvious UCM shape suggested a large input of bacteria.The ∑C21^-/∑C22^+ values varied from 1.82 to 3.9,and C21^+C22 /C28 ^+C 29 values ranged from 1.26 to 6.30,indicating that the sedimentary organic matter mainly originated from marine algae.The CPI and OEP values varied from 1.54 to 2.29 and from 4.48 to 4.82,respectively,with a significant odd even predominance.Pr/Ph values ranged from 0.34 to 0.76,significantly smaller than 1,with a clear distribution of C29 >C27 >C28 and C27 >C29 >C28 for regular steranes and a V-shaped C29 predominance and C27 predominance.This indicated that the sedimentary organic matter in the Prydz Bay originated from a mixed marine/continental source,and was deposited under a strongly reducing environment.The maturity parameters of the sedimentary strata from the Prydz Bay displayed significant inconsistency.Geochemical parameters of hopane C 32 22S/C 32 (22S+22R) and sterane C 29 αββ/(αββ+ααα) suggested a high maturity,but other geochemical parameters such as C29 ααα20S/C29 ααα(20S+20R),CPI and OEP reflected that those of columnar strata were within the range of modern marine sediments (lowly mature to immature),probably resulting from the development of microorganisms. 展开更多
关键词 PRYDZ BAY Sediment CORES Saturated hydrocarbons GEOCHEMICAL characteristics Environmental significance
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Linking Monsoon Activity with River-Derived Sediments Deposition in the Northern South China Sea 预览
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作者 GE Qian XU Dong +2 位作者 YE Liming YANG Kehong YAO Zhigang 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第5期1098-1104,共7页
The history of the East Asian monsoon(EAM)since Last Glacial Maximum is reconstructed based on records in a sediment core retrieved from the northern South China Sea.The provenance of organic carbon and the EAM’s evo... The history of the East Asian monsoon(EAM)since Last Glacial Maximum is reconstructed based on records in a sediment core retrieved from the northern South China Sea.The provenance of organic carbon and the EAM’s evolution are investigated using combined organic carbon,grain size,and AMS 14 C dating analysis.Responding to the strong winter monsoon,the marine organic matter was dominated in the sediments,andδ13 C of organic matter was high during the last glacial period.During the Holocene,the primary productivity decreased and the dilution effect of riverine inorganic clastics strengthened.Accordingly,the total organic carbon contents andδ13 C values decreased,and terrestrial organic matter content increased in the core sediments.The 4μm grain size fraction,as the environmental sensitive grain size component,is determined to reconstruct the paleoclimatic records.During the last glacial period,the contents of 4μm grain size component were mainly controlled by the sea level changes.Upon the Holocene,the influence of the sea level changes weakened and the roles of current system and provenance strengthened.The correlation between the EAM and solar insolation forcing is also discussed in this paper. 展开更多
关键词 organic carbon GRAIN size SEA level current system South China SEA East Asian MONSOON
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热带印度洋海表日增温年循环和半年循环
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作者 张田雷 闫运伟 陈莹莹 《海洋湖沼通报》 CSCD 北大核心 2019年第1期39-46,共8页
利用SeaFlux再分析数据和经验模型研究了热带印度洋海表日增温年循环和半年循环的时空分布特征及其机理。研究结果表明,热带印度洋海表日增温年循环振幅在绝大部分海区都较大;而半年循环振幅仅在北印度洋较大。对年循环而言,在17°... 利用SeaFlux再分析数据和经验模型研究了热带印度洋海表日增温年循环和半年循环的时空分布特征及其机理。研究结果表明,热带印度洋海表日增温年循环振幅在绝大部分海区都较大;而半年循环振幅仅在北印度洋较大。对年循环而言,在17°S以南海区以太阳辐射年循环的贡献为主,而在17°S以北海区以风速年循环的贡献为主;对于半年循环,在北印度洋以风速半年循环的贡献为主。本文还重点关注了以下两个海区:1)阿拉伯海西部,海表日增温年循环比半年循环振幅小;2)孟加拉湾中部,情况刚好相反。两海区相比,海表日增温年循环振幅在孟加拉湾中部较大;而半年循环振幅在阿拉伯海西部较大。这些差异都是由两海区不同的太阳辐射和风速年循环和半年循环造成的。 展开更多
关键词 海表日增温 年循环 半年循环 热带印度洋
Significant salinity increase in subsurface waters of the South China Sea during 2016-2017 预览
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作者 Xingrong Chen Zenghong Liu +2 位作者 Haiyan Wang Dongfeng Xu Lei Wang 《海洋学报:英文版》 SCIE CAS CSCD 2019年第11期51-61,共11页
The South China Sea(SCS)is the largest semi-enclosed marginal sea in the North Pacific.Salinity changes in the SCS play an important role in regional and global ocean circulation and the hydrological cycle.However,the... The South China Sea(SCS)is the largest semi-enclosed marginal sea in the North Pacific.Salinity changes in the SCS play an important role in regional and global ocean circulation and the hydrological cycle.However,there are few studies on salinity changes over the SCS due to lack of high-quality and long-term observations.In the past decade,the deployment of floats from the Argo program in the SCS and their accumulated temperature and salinity profiles have made it possible for us to examine salinity changes over the entire basin.In this study,salinity changes were investigated with Argo and underwater glider temperature and salinity observations and gridded temperature-salinity objective analyses(UK Met Office Hadley Centre EN4.2.1 objective analysis and China Argo Real-time Data Center BOA_Argo).The results indicated that the subsurface water in the entire SCS became significantly saltier during 2016-2017.The most significant salinity increase was found during 2016 in the northeastern SCS.The subsurface water in the northeastern SCS exhibited a salinity maximum above 35,which was recorded by three Argo floats during 2015-2016.Such high salinity water was rarely observed and reported prior to the Argo era.Average salinity of 2016-2017 along the 25.5σθ-23.5σθ isopycnal surfaces in the whole SCS is 0.014−0.130 higher than the climatology.Increases in subsurface salinity started from the northeastern SCS and extended southwestward gradually.Moreover,the subsurface salinity changes,especially in the northern SCS,exhibited a semiannual lead behind the subsurface Luzon Strait transport.Further analysis indicated that the predominance of advection,driven by subsurface Luzon Strait transport,led to salinification along the western boundary of the SCS.In other parts of the SCS,negative wind stress curl trends tended to preserve the high salinity characteristics of the subsurface water. 展开更多
关键词 South China Sea salinification SUBSURFACE Luzon Strait transport
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A multi-channel chemical sensor and its application in detecting hydrothermal vents 预览
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作者 Zhen Cai A J Mur Luis +3 位作者 Jiwan Han Kui Wang Huawei Qin Ying Ye 《海洋学报:英文版》 SCIE CAS CSCD 2019年第9期128-134,共7页
There are well-established chemical and turbidity anomalies in the plumes occurring vicinity of hydrothermal vents, which are used to indicate their existence and locations. We here develop a small, accurate multi-cha... There are well-established chemical and turbidity anomalies in the plumes occurring vicinity of hydrothermal vents, which are used to indicate their existence and locations. We here develop a small, accurate multi-channel chemical sensor to detect such anomalies which can be used in deep-sea at depths of more than 4 000 m. The design allowed five all-solid-state electrodes to be mounted on it and each (apart from one reference electrode) could be changed according to chemicals to be measured. Two experiments were conducted using the chemical sensors. The first was a shallow-sea trial which included sample measurements and in situ monitoring. pH, Eh, CO3^2- and SO4^2- electrodes were utilized to demonstrate that the chemical sensor was accurate and stable outside the laboratory. In the second experiment, the chemical sensor was integrated with pH, Eh, CO3^2- and H2S electrodes, and was used in 29 scans of the seabed along the Southwest Indian Ridge (SWIR) to detect hydrothermal vents, from which 27 sets of valid data were obtained. Hydrothermal vents were identified by analyzing the chemical anomalies, the primary judging criteria were decreasing voltages of Eh and H2S, matched by increasing voltages of pH and CO3^2- . We proposed that simultaneous detection of changes in these parameters will indicate a hydrothermal vent. Amongst the 27 valid sets of data, five potential hydrothermal vents were targeted using the proposed method. We suggest that our sensors could be widely employed by marine scientists. 展开更多
关键词 CHEMICAL sensor MULTI-CHANNEL HYDROTHERMAL VENTS detection CHEMICAL ANOMALIES SWIR
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浙江省专门(工读)学校现状调查
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作者 阮玲玲 杨晓慧 《上海教育科研》 北大核心 2019年第6期56-59,共4页
本研究选取浙江省内唯一的一所专门学校初三及高一学生作为对象,对学生来源、家庭背景、心理健康状况、行为表现及学业成绩进行调查,结果发现:专门学校办学规模较小,招生生源有限制;学生普遍存在心理健康状况不良、行为问题严重、学业... 本研究选取浙江省内唯一的一所专门学校初三及高一学生作为对象,对学生来源、家庭背景、心理健康状况、行为表现及学业成绩进行调查,结果发现:专门学校办学规模较小,招生生源有限制;学生普遍存在心理健康状况不良、行为问题严重、学业水平较低等问题;专门学校学生家庭关系复杂,家庭教育缺失。建议采取多方面措施,深化发展新时期的专门教育。 展开更多
关键词 专门(工读)学校 学生现状 调查研究
Characteristics of particle fluxes in the Prydz Bay polynya, Eastern Antarctica
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作者 Zhengbing HAN Chuanyu HU +4 位作者 Weiping SUN Jun ZHAO Jianming PAN Gaojing FAN Haisheng ZHANG 《中国科学:地球科学英文版》 SCIE EI CAS CSCD 2019年第4期657-670,共14页
The settling of particulate carbon in seawater is a key component of the ocean carbon cycle. We deployed a set of sediment trap in the polynya of Prydz Bay from December 2010 to December 2011 to investigate the season... The settling of particulate carbon in seawater is a key component of the ocean carbon cycle. We deployed a set of sediment trap in the polynya of Prydz Bay from December 2010 to December 2011 to investigate the seasonal variations in particle fluxes. There was a clear seasonal variation in the particle fluxes, with maximum and minimum fluxes recorded during the summer and winter, respectively. The average total flux over the sampling period was 193.58 mg m-2d-1, and the average fluxes of organic carbon(Corg), inorganic carbon(Cinorg), and biogenic silica(Sibio) were 721.78, 28.67, and 2382.80 μmol m-2 d-1, respectively. Sibiowas the main contributor to the total mass flux, and strongly correlated with Corg. The high Sibio/Corgmolar ratios(>1) suggest that Corgwas transported to deep sea in association with Sibio. By comparing remote sensing data of sea ice and chlorophyll in the upper water column, we found that the dynamics of carbon fluxes were closely related to changes in sea ice. Algae in sea ice may have a key role in biological pump processes in early summer. Apart from the ice algae bloom period, variations in carbon fluxes generally corresponded with phytoplankton blooms in the upper water. The ballast effect controlled the particle settling velocity and the efficiency of the biological pump. Sea ice rafts initiated the first particle export event and enhanced the particle settling efficiency during melting period. As diatoms might become less dominant in the ice-free area, sea ice loss may cause the efficiency of the biological pump efficiency to decrease over the long term. 展开更多
关键词 PRYDZ BAY Particle FLUXES Polynya BALLAST effect Biological PUMP efficiency
Distribution and Sources of Organic Matter in Surface Sediments of the Northern Bering and Chukchi Seas by Using Bulk and Tetraether Proxies 预览
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作者 JI Zhongqiang JIN Haiyan +5 位作者 STEIN Ruediger LI Zhongqiao BAI Youcheng LI Hongliang ZHANG Yang CHEN Jianfang 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第3期563-572,共10页
The organic matter (OM) preserved in Arctic Ocean sediments is of great importance to the global carbon budget. How-ever, works that apply multiple proxies to determine the distribution and concentration of organic ca... The organic matter (OM) preserved in Arctic Ocean sediments is of great importance to the global carbon budget. How-ever, works that apply multiple proxies to determine the distribution and concentration of organic carbon (OC) in the surface sedi-ments of the northern Bering and Chukchi Seas remain limited. Here a multiproxy approach based on bulk OM parameters and the branched vs. isoprenoid tetraether (BIT) index was used to investigate the distribution and sources of OM in the surface sediments of the northern Bering and Chukchi Seas. Binary and ternary mixing models were applied to trace the contribution of different OC sources to the total OC in the study area. The δ13C values of the sediments provided by the binary model showed that the proportion of terrestrial OC fell in the range of 27.4%–79.8% (46.2% on average). The BIT index returned the lowest fraction (4.8%–27.3%, 12.0% on average). The ternary mixing model was employed to determine the plant-, soil-, and marine-derived fractions of the total OM. The ternary model showed that 11.5%±6.3%, 31.4%±9.5%, and 57.1%±12.4% of OM in the sediment of the study area was derived from soil, plants, and marine sources, respectively. The differences in OM composition between the west and east sides of the Chukchi Sea were controlled by OM inputs from key water masses (i.e., Anadyr Water and Alaska Coastal Water), river discharge, and the nutrient supply from the Pacific inflow that supports marine productivity. 展开更多
关键词 northern BERING SEA CHUKCHI SEA organic matter GDGTs BULK parameters
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Comparison of Phytoplankton Communities Between Melt Ponds and Open Water in the Central Arctic Ocean 预览
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作者 ZHANG Tianzhen ZHUANG Yanpei +4 位作者 JIN Haiyan LI Ke JI Zhongqiang LI Yangjie BAI Youcheng 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第3期573-579,共7页
Climate warming has a significant impact on the sea ice and ecosystem of the Arctic Ocean.Under the increasing numbers of melt ponds in Arctic sea ice,the phytoplankton communities associated with the ice system are c... Climate warming has a significant impact on the sea ice and ecosystem of the Arctic Ocean.Under the increasing numbers of melt ponds in Arctic sea ice,the phytoplankton communities associated with the ice system are changing.During the 7th Chinese National Arctic Research Expedition cruise in summer 2016,photosynthesis pigments and nutrients were analyzed,revealing differences in phytoplankton communities between melt ponds and open water in the central Arctic.Photosynthetic pigment analysis suggested that Fuco(5-91μg m^-3)and Diadino(4-21μg m^-3)were the main pigments in the open water.However,the melt ponds had high concentrations of Viola(7-30μg m^-3),Lut(4-59μg m^-3)and Chl b(11-38μg m^-3),suggesting that green algae dominated phytoplankton communities in the melt ponds.The significant differences in phytoplankton communities between melt ponds and open water might be due to the salinity difference.Moreover,green algae may play a more important role in Arctic sea ice ecosystems with the expected growing number of melt ponds in the central Arctic Ocean. 展开更多
关键词 the CENTRAL Arctic Ocean MELT PONDS PHOTOSYNTHESIS pigments nutrients PHYTOPLANKTON COMMUNITIES
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Distribution Patterns of Major and Trace Elements andProvenance of Surface Sediments on the ContinentalShelf off Western Guangdong Province andNortheastern Hainan Island 预览
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作者 GE Qian XUE Z. George +3 位作者 YE Liming XU Dong YAO Zhigang CHU Fengyou 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第4期849-858,共10页
A coupled approach based on grain size and geochemical elements is used to trace the provenance of surface sediments and to confirm the distribution patterns of grain size and elements on the continental shelf off wes... A coupled approach based on grain size and geochemical elements is used to trace the provenance of surface sediments and to confirm the distribution patterns of grain size and elements on the continental shelf off western Guangdong Province and northeastern Hainan Island. The mean grain size ranges from 0.05 φ to 7.28 φ with a mean value of 5.60 φ. The average concentra- tions of major elements descend in the order of SiO2 > Al2O3 > CaO > Fe2O3 > K2O > MgO > Na2O > TiO2 > P2O5 > MnO, while those of trace elements exhibit a descending order of Sr > Rb > Zn > V > Cr > Pb > Ni > Cu > As > Cd. On the basis of the distribution patterns of elements and results of statistical analysis, the study area is classified into three zones. Zone I locates on the continental shelf off western Guangdong Province, and the sediments are mainly from Pearl River, Taiwanese rivers, and small rivers nearby. Zone II locates in the eastern exit of Qiongzhou Strait and the coastal area off Leizhou Peninsula, and the sediments are mainly from the ero- sion products of Qiongzhou Strait and Hainan Island. Zone III locates off the eastern Hainan Island and the continental shelf deeper than 50 m isobaths, and the sediments are mainly from Hainan Island and coral reef. The influence from open water should also be considered. Results indicate that the grain size is the main controlling factor for major and trace element contents and that anthropo- genic impact and biological activity also play an important role in the distribution of these elements. 展开更多
关键词 grain size GEOCHEMICAL elements WESTERN Guangdong Province NORTHEASTERN HAINAN ISLAND controlling factor
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一张小纸玩出大乾坤——五年级体验类习作《撕纸游戏》教学过程与评析 预览
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作者 朱红 魏丽君 《教学月刊:小学版(语文)》 2019年第1期42-45,共4页
【习作目标】1.通过“玩纸”游戏的前后对比体验,激发学生的习作兴趣和表达欲望。2.借助学生的当场片段练习,引导学生通过分解动作写清楚游戏的过程。3.通过对当场习作的比较和欣赏,懂得借由写游【习作目标】1.通过“玩纸”游戏的前后... 【习作目标】1.通过“玩纸”游戏的前后对比体验,激发学生的习作兴趣和表达欲望。2.借助学生的当场片段练习,引导学生通过分解动作写清楚游戏的过程。3.通过对当场习作的比较和欣赏,懂得借由写游【习作目标】1.通过“玩纸”游戏的前后对比体验,激发学生的习作兴趣和表达欲望。2.借助学生的当场片段练习,引导学生通过分解动作写清楚游戏的过程。3.通过对当场习作的比较和欣赏,懂得借由写游戏者的感受来写具体游戏过程的习作方法。戏者的感受来写具体游戏过程的习作方法。 展开更多
关键词 习作兴趣 游戏过程 教学过程 五年级 引导学生 撕纸 乾坤 表达欲望
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Distribution and Sources of Polycyclic Aromatic Hydrocarbons in the Sediment Cores M2 from the Prydz Bay and Implications for Sedimentary Environment 预览
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作者 Yang Dan Han Xibin +3 位作者 Zhang Haisheng Zhang Yicheng Xu Xudan Zhang Huijuan 《气象与环境研究:英文版》 CAS 2019年第4期15-22,共8页
In this study, the polycyclic aromatic hydrocarbons (PAHs) from the sediment cores M2 in the Pryza Bay of the Antarctica were quantitatively measured using GC-MS analysis, and it is found that the PAHs mainly included... In this study, the polycyclic aromatic hydrocarbons (PAHs) from the sediment cores M2 in the Pryza Bay of the Antarctica were quantitatively measured using GC-MS analysis, and it is found that the PAHs mainly included bicyclic naphthalene compounds, tricyclic phenanthrene and fluorine series (dibenzofuran and dibenzothiophene), and tetracyclic fluoranthene, pyrene and chrysene series. The results showed that the phenanthrene series with low molecular weight (tricyclic compounds) had a relatively higher content than the series with high molecular weight (tetracyclic compounds). The fluoranthene/(fluoranthene and pyrene) ratio of M2 varied from 0.46 to 0.54. Integrated with the content of 1,7-dimethylphenanthrene and terrigenous chrysene, it is inferred that PAHs in the sediments from the Pryzd Bay were originated from a mixed source of the products of petroleum, refined products and coal combustion, natural source and terrigenous higher plants. Complete methyl dibenzothiophene and dimethyldibenzothiophene series compounds were detected in the sediment cores, which are closely associated with a reducing environment. The ratio of dibenzothiophene to dibenzofuran was between 0.46 and 3.21, mostly greater than 0.7. Combined with the oxidation/reduction index (Pr/Ph) ranging from 0.45 to 0.61 for the sediment cores, it is indicated that these compounds were formed in a normal reducing environment. Geochemical parameters of PAHs such as TNR-1 (0.53-1.57), MPI (0.24-1.21), MDR (1.83-5.57), and MDBI (0.41-0.93), and maturity parameters such as C 29 /C 29 (+), C 31 22S/C 31 (22S+22R), C 32 22S/C 32 (22S+22R) and Ts/(Tm+Ts) were all indicative of high maturity. However, all the above parameters were significantly deviated from those of modern sediments and modern organisms, which undoubtedly shows the input of exogenous mature organic matter. 展开更多
关键词 ANTARCTICA Sediment core POLYCYCLIC AROMATIC hydrocarbons Material source SEDIMENTARY environment
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Kuroshio intrusion into the South China Sea with an anticyclonic eddy: evidence from underwater glider observation 预览
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作者 LIU Zenghong CHEN Xingrong +2 位作者 YU Jiancheng XU Dongfeng SUN Chaohui 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第5期1469-1480,共12页
In this study, high-resolution temperature and salinity data obtained from three Sea-Wing underwater gliders were used together with satellite altimeter data to track the vertical thermohaline structure of an anticycl... In this study, high-resolution temperature and salinity data obtained from three Sea-Wing underwater gliders were used together with satellite altimeter data to track the vertical thermohaline structure of an anticyclonic eddy that originated from the loop current of the Kuroshio southwest of Taiwan, China. One of the gliders crossed the entire eddy and it observed a remarkable warm anomaly of as much as 3.9℃ extending to 500 dbar from the base of the mixed layer. Conversely, a positive salinity anomaly was found to be above 200 dbar only in the anticyclonic eddy, with a maximum value of >0.5 in the mixed layer. Below the mixed layer, water of higher salinity (>34.7) was found, which could have been preserved through constrained vertical mixing within the anticyclonic eddy. The salinity in the upper layer of the anticyclonic eddy was much similar to that of the northwestern Pacific Ocean than the northern South China Sea, reflecting Kuroshio intrusion with anticyclonic eddy shedding from the loop current. 展开更多
关键词 anticyclonic EDDY South China SEA KUROSHIO Sea-Wing underwater GLIDER
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Catalogue of Polychaete species (Annelida) described from China Seas during 2008–2017 预览
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作者 WANG Yueyun WANG Chunsheng 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第2期724-735,共12页
China Seas are one of the most diverse regions in the Pacific. Though much eff ort has been made to explore its biodiversity, the polychaetes diversity is still poorly known. A large number of species records are base... China Seas are one of the most diverse regions in the Pacific. Though much eff ort has been made to explore its biodiversity, the polychaetes diversity is still poorly known. A large number of species records are based on ecological investigation rather than taxonomical studies. We update the Polychaete species taxonomicaly described from China coastal waters during 2008–2017 and list them as a catalogue. The catalogue contains 47 species of 32 genera and 17 families, the type depository, type locality and geographic distribution. Some taxonomic problems are present in remarks. 展开更多
关键词 CHECKLIST ANNELIDA POLYCHAETA taxonomy China SEAS
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