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鼎湖山土壤有机质深度分布的剖面演化机制

土壤学报 2005年第1期42卷 1-8页

作者：陈庆强沈承德孙彦敏彭少麟易惟熙李志安姜漫涛华东师范大学河口海岸国家重点实验室上海200062 中国科学院广州地球化学研究所广州510640 中国科学院华南植物研究所广州510650

根据鼎湖山森林植被带(SL)、灌丛—草甸过渡带土壤剖面(GC)有机质含量,有机质Δ14C、δ13C值,土壤粘粒含量及孢粉分析结果,研究华南亚热带山地土壤有机质深度分布特征的成因机制。结果表明土壤有机质的深度分布特征与土壤剖面的发育过... 详细信息

根据鼎湖山森林植被带(SL)、灌丛—草甸过渡带土壤剖面(GC)有机质含量,有机质Δ14C、δ13C值,土壤粘粒含量及孢粉分析结果,研究华南亚热带山地土壤有机质深度分布特征的成因机制。结果表明土壤有机质的深度分布特征与土壤剖面的发育过程密切相关,随深度增大,有机质的来源数量不断减少,而成土时间增加,分解作用导致的有机质含量降低幅度增大,有机质含量不断减少。土壤有机质14C表观年龄随深度增加,土壤有机质δ13C值与有机质含量的深度变化具有明显对应关系,这些都是土壤剖面发育过程中有机质不同更新周期组分呈规律性分解的结果。粘粒的深度分布反映土壤剖面淋滤淀积的特点,表明土壤剖面经受了长期成土风化。土壤剖面的上述特征均为剖面发育过程中不断沉积、不断成土的结果,表明土壤剖面成土演化对于有机质深度分布具有显著制约。

关键词：土壤剖面土壤有机质有机质含量发育过程成土鼎湖山深度分布 δ^13C 表观成因机制

Flocculation process of fine-grained sediments by the combined effect of salinity and humus in the Changjiang Estuary

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Acta Oceanologica Sinica 2007年第1期26卷 140-149页

作者： liU Qizhen li jiufa DAI Zhijun li Daoji State Key Laboratory of estuarine and coastal research East China Normal University Shanghai 200062 China

For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum （TM） . For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum （TM） . The effects of salinity and humus on the fine-grained sediments have been analyzed through the synthetic study of the aspects of flocculation/coagulation power （ F）, diameter （D） and zeta potential （Z）. And the microcosmic configuration of the flocs has been analyzed by using a scan electron microscope and Fourier Transform Infrared Spectrometry. The results show that：（ 1 ） with the increase of salinity, F and D become greater and Z becomes smaller, and with the increase of the concentration of humus, F becomes smaller, but D and Z become greater; （2） the microcosmic configuration of the flocculation shows that humus packs on the fine sediments in the form of salt, and the flocculation model of C - P - OM （C stands for clay; P cations; OM organic materials） can successfully demonstrate the mechanism of the formation of the finegrained sediments in the high-turbid area of the Changjiang Estuary.

关键词： Changjiang Estuary fine-grained sediment floceulation salinity

research on the adsorptive kinetic experiments on humus and its spacial variations in the Changjiang (Yangtze) estuary

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Acta Geochimica 2006年第S1期 259-259页

作者： Qizhen liU1, jiufa li1, Gui FU1, Weichang LU2, Daoji li1 1 State Key Laboratory of estuarine and coastal research, east china normal university, shanghai 200062, china 2 Department of Chemistry, east china normal university, shanghai 200062, china

Flood-ebb asymmetry in current velocity and suspended sediment transport in the Changjiang Estuary

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Acta Oceanologica Sinica 2016年第10期35卷 37-47页

作者： li Zhanhai WANG Yaping CHENG Peng ZHANG Guoan li jiufa State Key Laboratory of estuarine and coastal research East China Normal University School of Geographic and Oceanographic Sciences Nanjing University College of Ocean and Earth Sciences Xiamen University

Time series measurements were conducted on suspended sediment and current velocity from neap tide to spring tide in the South Branch of the upper Changjiang Estuary in the summer of 2011. Strong flood-ebb asymmetry in the current velocity was observed in the South Branch as a result of high river runoff and tide deformation, in which the magnitude and duration of ebb currents were significantly greater than those of flood currents. The suspended sediment concentration（SSC） and suspended median grain size also exhibited remarkable flood-ebb variation; these variables were considerably larger during the ebb than during the flood and increased from neap to spring tide. Affected by the strong asymmetry in the current velocity and SSC between the flood and ebb,suspended sediment flux during the ebb was notably larger than during the flood, and a seaward tidal net flux was observed in each tidal cycle. The balance of sediment flux illustrates that the seaward sediment transport was dominated by river flow and tidal trapping and the landward sediment transport was dominated by the Stokes drift and the shear effect. Notable resuspension occurred during the spring and moderate tides. The critical velocity for the resuspension of bed sediments was estimated based on the correlation between current velocity with SSC and suspended median grain size. The results show that the critical velocity was approximately 40 cm/s during the flood phases and approximately 80 cm/s during the ebb phases because the surficial flood bed sediments located in the lower reach are much finer than the surficial ebb bed sediments located in the upper reach. The flood-ebb variation in the critical erosion velocity has significant effect on the intratidal variation of SSC and sediment transport process, and it is a common phenomenon in many estuaries of the world due to the complicated spatial distribution of bed sediments.

关键词： flood-ebb asymmetry suspended sediment concentration resuspension river runoff flux the upper Changjiang Estuary

Intratidal and neap-spring variations of suspended sediment concentrations and sediment transport processes in the North Branch of the Changjiang Estuary

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Acta Oceanologica Sinica 2015年第1期34卷 137-147页

作者： li Zhanhai li Michael Z DAI Zhijun ZHAO Fangfang li jiufa State Key Laboratory of estuarine and coastal research East China Normal University Geological Survey of Canada (Atlantic) Bedford Institute of OceanographyDartmouthB2Y 4A2Canada

Profles of tidal current and suspended sediment concentration （SSC） were measured in the North Branch of the Changjiang Estuary from neap tide to spring tide in April 2010. The measurement data were analyzed to determine the characteristics of intratidal and neap-spring variations of SSC and suspended sediment transport. Modulated by tidal range and current speed, the tidal mean SSC increased from 0.5 kg/m3 in neap tide to 3.5 kg/ma in spring tide. The intratidal variation of the depth-mean SSC can be summarized into three types： V-shape variation in neap tide, M-shape and mixed M-V shape variation in medium and spring tides. The occurrence of these variation types is controlled by the relative intensity and interaction of resuspension, settling and impact of water exchange from the rise and fall of tide. In neap tide the V-shape variation is mainly due to the dominant effect of the water exchange from the rise and fall of tide. During medium and spring tides, resuspension and settling processes become dominant. The interactions of these processes, together with the sustained high ebb current and shorter duration of low-tide slack, are respon- sible for the M-shape and M-V shape SSC variation. Weakly consolidated mud and high current speed cause significant resuspension and remarkable flood and ebb SSC peaks. Setting occurs at the slack water periods to cause SSC troughs and formation of a thin flufflayer on the bed. Fluxes of water and suspended sediment averaged over the neap-spring cycle are all seawards, but the magnitude and direction of tidal net sediment flux is highly variable.

关键词： suspended sediment concentration intratidal and neap-spring variation impact of waterexchange resuspension settling Changjiang (Yangtze River) Estuary

The self-regulation process and its mechanism of channels' bed changes in the Changjiang(Yangtze) Estuary in china

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Acta Oceanologica Sinica 2015年第7期34卷 123-130页

作者： ZHANG Xiaohe li jiufa ZHU Wenwu CHENG Heqin CHEN Wei State Key Laboratory of estuarine and coastal research East China Normal University institute for Marine and Atmospheric research Utrecht Utrecht University

Recent bathymetric changes in the Changjiang Estuary under the influence of artificial regulation engineerings and basin reservoirs have been analyzed based on the maritime charts since 1997 and recent fieldworks. The results indicate a slight erosion of the channels in the upper and middle estuary, continuing deposition and seaward move of the mouth bar crest and intensifying erosion at the nearshore seabed. It is noteworthy that the morphological evolution caused by intensive human activities dominates over the changes from nature process. First, the riverbes are eroded overall in the South Branch （SB）, the South Channel （SC） and the upper and middle reaches of the North Channel （NC）. The nearshore seabed outside the river mouth is being eroded slightly, which is attributed to the declining sediment supply from the Changjiang Basin due to the construction of the Three Gorges Dam upstream. The sediment above the seabed is very active and coarsened, meanwhile, sand waves are becoming more distinct. Second, a deposition occurs in the North Brach （NB）, the mouth of the NC, the mouth bars of the North Passage （NP） and the South Passage （SP） and especially the main channel of the NP, where it shows a massive siltation after the deep waterway project. The reasons for the recent changes are not only the dynamic structure in estuarine mouth bars, but also the supply of sediment resuspension in a local and offshore area. Meanwhile, the severe erosion and siltation in some reaches is related to the construction of estuarine engineerings. It is indicated that the Changjiang Estuary is gradually self-adjusted and adapting to the varying natural factors and intensive human activities. The study on the mechanism of self-regulation of the recent bathymetric changes in the Changjiang Estuary has important and practical significance.

关键词： Changjiang Estuary bathymetric changes self-regulation human activities tidal current sediment transport

Modern pollen distributions in Qinghai-Tibetan Plateau and the development of transfer functions for reconstructing Holocene environmental changes

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Modern pollen distributions in Qinghai-Tibetan Plateau and t...

中国科学院地质与地球物理研究所第11届（2011年度）学术年会

作者： Houyuan Lu~(a,*),Naiqin Wu~a,Kam-biu liu~b,liping Zhu~c,Xiangdong Yang~d,Tandong Yao~c,Luo Wang~a, Quan li~a,Xingqi liu~d,Caiming Shen~e,Xiaoqiang li~f,Guobang Tong~g,Hui Jiang~h aKey Laboratory of Cenozoic Geology and Environment,institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,china b Department of Oceanography and coastal Sciences,Louisiana State university,Baton Rouge,LA 70803,USA cinstitute of Tibetan Plateau research,Chinese Academy of Sciences,Beijing 100085,china d State Key Laboratory of Lake Science and Environment,Nanjing institute of limnology and Geography,Chinese Academy of Sciences,Nanjing 210008,china e Atmospheric Sciences research Center,State university of New York,Albany,NY 12203,USA f institute of Vertebrate Paleontology and Paleoanthropology,Chinese Academy of Sciences,Beijing 100044,china g institute of Hydrology and Geology,Chinese Academy of Geological Sciences,Zhengding 050803,china h State Key Laboratory of estuarine and coastal research,east china normal university,shanghai 200062,china

This study investigates the distribution of modern pollen assemblages in the Qjnghai-Tibetan Plateau, china,based on surface soil samples collected at 1202 sites along an altitudinal gradient of 10 -5500 m asl,where mean annual precipitation(MAP) ranges from 12 to 1840 mm and mean annual temperature(MAT) from -1 to 21.5℃.A total of 153 pollen taxa were found with relative abundances greater than 1%in at least two *** correspondence analysis(CCA) was used to determine the main environmental variables influencing pollen *** results reveal that MAP is the most significant dominant ***,MAT,altitude(ALT),July temperature(MT7),and relative humidity(HHH) are also significant variables that clearly follow the gradients in the CCA ordination, suggesting that pollen assemblages probably not only reflect a single climatic parameter,but also a variety of other climatic inter-related parameters. Transfer functions,based on locally weighted weighted averaging(LWWA),were developed for MAP (R-boot = 0.89,RMSEP = 109 mm),MAT(R-boot = *** = 2.3℃),ALT(R-boot = 0.73, RMSEP = 597 m),HHH(R-boot = 0.82,RMSEP = 4.5%),and July mean precipitation(MP7)(R- boot = 0.87,RMSEP = 23 ram).Overall,our results confirm that pollen can provide reliable estimates of the primary climatic *** application of the LWWA model to the fossil records of Chen Co Lake allowed quantitative inferences to be made about Holocene climatic changes in the southern Tibetan Plateau,suggesting that LWWA is a robust calibration method for quantitative palaeo-environ-mental reconstruction based on pollen data in the regions.

关键词： Qinghai-Tibetan plateau Vegetation Pollen Transfer functions Holocene Climatic changes

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长江河口悬沙输移特性

泥沙研究 1986年第1期 1-13页

作者：沈焕庭李九发朱慧芳周福根华东师范大学河口海岸研究所同济大学海洋地质系

长江来水来沙具有水量沙量大,有明显的季节变化。水量与沙量时而相应时而不相应、流量最大月后的沙量比流量最大月前大等特点.口门附近的悬沙浓度和净输沙量在时间上有明显的涨落潮、大小潮和洪枯季变化。在空间上,三条汉道各异,同一汊... 详细信息

长江来水来沙具有水量沙量大,有明显的季节变化。水量与沙量时而相应时而不相应、流量最大月后的沙量比流量最大月前大等特点.口门附近的悬沙浓度和净输沙量在时间上有明显的涨落潮、大小潮和洪枯季变化。在空间上,三条汉道各异,同一汊道拦门沙内外也有较大差异。北港是目前长江输水输沙的主要通道。流域来沙约有50％以上在南支口门附近沉积,南港口外的水下三角洲是主要淤积区。122°30′E～123°E间是悬沙向东扩散的一条重要界线,入海泥沙主要向东偏南方向扩散。

关键词：含沙量北槽南槽含沙浓度悬沙悬移质北港枯季输移特性来水来沙口门潮流速输沙量悬沙浓度长江河口长江

Distributions of sediments of the tidal flats in response to dynamic actions,Yangtze （Changjiang） Estuary

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Journal of Geographical Sciences 2011年第4期21卷 719-732页

作者： YAN Hong DAI Zhijun li jiufa ZHAO Jianchun ZHANG Xiaoling ZHAO Junkai State Key Laboratory of estuarine and coastal research East China Normal University Shanghai 200062 China Faculty of Civil Engineering and Geosciences Delft Technical University Delft 2600 the Netherlands

Sediment samples with high spatial resolution （432 samples in total） and flow data were collected on the tidal flats in the mouth-bar region of the Yangtze Estuary. The data was collected in July 2005, July 2006 and May 2007. The samples were analyzed with a particle sizer, resulting in the sediment distribution. The grain sizes and related parameters were analyzed. The results were presented in a ternary diagram. The sediment mainly consisted of sand, silty sand, sandy silt, sand-silt-clay, silt and clayey silt. And sand skeletons and clay matrices were found. At Nanhui Shoal, silt skeletons could be identified as well. Furthermore, the results were discussed per shoal. Although some depth dependencies were found per shoal, no general relation was found. The results are as follows： sediment located at these tidal flats of the Yangtze Estuary was mainly composed of sand, silty sand and silt. The median grain size in sediment was relatively complex with a range from 2.5 φ to 8 φ. The distributions of sorting coefficients ranging from 1 to 2 were in agreement with median sizes. It was suggested that sediment of the tidal flats was coarser and better sorted or finer and worse sorted. The skewness in sediment distribution varied from 0.1 to 0.8. In addition, the distributions of sorting coefficient and skewness in sediment at Chongming eastern Shoal, Hengsha eastern Shoal and Jiuduan Shoal were of similar characteristics because there were closely positive correlated relationships among these parameters. However, due to the location difference between Nanhui Southern Shoal and eastern Shoal, the values of sorting coefficient and skewness had relatively large distinctions. The tracks of sediment transport could be described based on the distributions of sediment, which might reveal sediment transport controlled by two dominant hydrodynamic factors of current and wave. It was appreciable that coarser sediment with lower sorted coefficient was affected by dominant ebb curr

关键词： sediment tidal flat deposition wave action tidal current Yangtze (Changjiang) Estuary