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Sediment dynamic responses of coastal salt marsh to typhoon “KAEMI” in Quanzhou Bay,Fujian Province,China

Chinese Science Bulletin 2009年第1期54卷 120-130页

作者： WANG AiJun GAO Shu CHEN Jian LI DongYi Ministry of Education Key laboratory for coast and island development Nanjing University Nanjing 210093 China Open laboratory for coast & Ocean Environmental Geology Third Institute of Oceanography State Oceanic Administration Xiamen 361005 China

In order to understand the mechanisms of coastal protection by salt marshes during typhoon events,in situ measurements of water level,tidal current speed and direction,and suspended sediment concen-tration (SSC) were carried out using Electromagnetic Current Meter (EMCM,AEM HR),miniature pres-sure sensor (MkV/D) and Seapoint Turbidity Meter (STM) sensor on a tidal flat in Quanzhou Bay,during the period when the typhoon "KAEMI" was passing through the region. The analysis of the data ob-tained shows that the near-bed current speed within the Spartina alterniflora marsh was generally be-low 5 cm s-1,which was apparently smaller than on the adjacent bare flat (i.e. 5―30 cm s-1). The change in the near-bed current speed in response to the typhoon event was not significant within the S. al-terniflora marsh,but the current direction was influenced by the typhoon. The effect of the typhoon on the SSC was highly significant,with the SSC reaching 13 to 19 times the values on the bare flat or within the marsh under fair weather conditions; the near-bed SSC within the marsh was higher than on the bare flat,after the typhoon landed. The near-bed suspended sediment fluxes within the marsh and on the bare flat during the typhoon event were both enhanced,i.e.,4 times larger than under fair weather conditions. During the ebb,the bottom shear stress on the bare flat exceeded the critical shear stress for sediment motion for most of the ebb duration of the tide and,therefore,the bed sediment was eroding,with the erosion flux after the typhoon landed being around 2 to 3 times the value associated with fair weather conditions. In contrast,within the S. alterniflora marsh,the bottom shear stress was mostly lower than the critical shear stress for sediment motion,or lower than the critical shear stress for the maintenance of suspension; hence,the marsh surface was dominated by settling processes,with a settling flux during the typhoon being 3 to 6 times compared with the fair weather sit

关键词：碱湿地沉淀物动态过程台风福建

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Grain-size distribution patterns of suspended sediment in response to hydrodynamics on the Dafeng intertidal flat, Jiangsu, China

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Acta Oceanologica Sinica 2006年第6期25卷 63-77页

作者： LI Zhanhai GAO Shu CHEN Shenliang WANG Yaping state Key laboratory of Estuarine and coastal Research East China Normal University Shanghai 200062 China Key laboratory of coast and island development of Ministry of Education Nanjing University Nanjing 210093 China

Patterns of grain-size distributions of suspended sediment in relation to resuspension, settling, and tidal processes are investigated, based on in situ measurements over the Dafeng intertidal flat, on the Jiangsu coast, in the summer of 2002 and 2003. The suspended sediment here is dominated by fine and very fine silt, with a mean grain-size of 7 - 13 μm. The patterns of the grainsize distributions of suspended sediment during a tidal cycle are characterized by two types： one stable type representing insignificant spatial and temperal variations; and the other bimedal type with significant variations. The main factors influencing the grainsize distributions include resnspension, settling, suspended sediment imported into intertidal flats during the flood phase, and the grain-size distribution of seabed sediment. Resuspension increases the coarse particle content, enhances the mean grain-size of suspended sediment, and results in grain-size distributions for the suspended sediment similar to those of seabed sediment; the settling process has opposite effects on the suspended sediment. When resuspension occurs, the gain-size distributions of suspended sediment in the lower part of water column respond significantly to the current velocity. Where the influence of resuspension and settling processes is weak, the grain-size distributions of suspended sediment appear to be stable and almost identical for the various parts of intertidal flats during different measurement periods. Such distributions are referred to the background grain-size distribution, for which the mean grain-size over the Dafeng intertidal flat is around 7 μm.

关键词： grain-size distributions suspended sediment resuspension settling Jiangsu coast

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Late Oligocene Sedimentary Hiatus in Deep Sea Area of South China Sea, Result of Calcareous Nannofossils from ODP Site 1148

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Journal of China University of Geosciences 2004年第1期15卷 69-74页

作者： Su Xin Key laboratory of Lithospheric and Lithoprobing Technology, China University of Geosciences, Ministry of Education, Beijing 100083, China state pilot laboratory of coast & island development, Nanjing University, Nanjing 210093, China Key laboratory of Lithospheric and Lithoprobing Technology China University of Geosciences Ministry of Education Beijing 100083 China state pilot laboratory of coast & island development Nanjing University Nanjing 210093 China

In order to determine the age of the sedimentary hiatus and its geological significance, a study of the calcareous nannofossil biostratigraphy was carried out. Detailed stratigraphical data of the Late Oligocene-Early Miocene diagnostic species thus obtained. The nannofossil zonation of this interval was subdivided and the Oligocene-Miocene boundary was further determined. Several last Late Oligocene events were recognized, indicating a long-term sedimentary hiatus in the uppermost Upper Oligocene. The time span of the hiatus was estimated for about 2.2 Ma, at least from 23.9 to 26.1 Ma. The lithological and geophysical data from Site 1148 indicate some abrupt sedimentary changes that occurred below and above the hiatus. This hiatus at Site 1148 was probably related to the tectonic change, a major ridge jump during the seafloor spreading in the Late Oligocene South China Sea.

关键词： sedimentary hiatus calcareous nannofossils Late Oligocene ODP Site 1148 South China Sea.

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A Model for Environmental Impact Assessment of Land Reclamation

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China Ocean Engineering 2007年第2期21卷 343-354页

作者：郭伟李书恒毛亮殷勇朱大奎 Key laboratory of coast and island development of Ministry of Eduation Nanjing University Department of Geography State University of New York at BuffaloUSA

Land reclamation is a complex marine environmental engineering and has a huge impact on social, economic, and physical environment. Reclamation environmental impact assessment （REIA） is also a complicated project, including the assessment of social economic background, ocean engineering, coastal geomorphology, sediment transportation, marine hydrodynamics and marine ecosystem and so on. Nowadays, a large number of land reclaimed projects have been carried out or in the process of construction along the coastal zone, thus, it is necessary to build up a fnmlework on REIA to evaluate and quantify the environmental changes, to contribute to reclamation program, to reduce marine environmental disasters, and to sustain development of coastal zone. This article focuses on the research of REIA framework theory and puts forward a REIA model on land reclaimed evaluation, at the same time, applies this assessment system in Shenzhen City, which is a highly developed coastal city with an expectation of land reclamation. By use of the Remote Sensing （RS） and Geographic Information System （GIS） techniques, along with the topographic map and in situ survey in recla- mation area, it concludes that the area of 2680 hectares in total has been reclaimed in Shenzhen city by the end of the year 2000. Thus, reclamation is usually applied to meet the needs for infrastructure, such as harbors, industries and highways in Shenzhen City. However, some serious negative impacts have been created to the coastal environment shown clearly in the following aspects. Firstly, it caused the dramatic changes of tidal flat and channels along the western coast, made this area more unstable, which is threatening the function of the harbor in this area. Secondly, Tidal prism has decreased rapidly. During the 20 years of reclamation, the tidal prism has been reduced by 20% - 30% along the western coast in the Lingdingyang Estuary, and 15.6% in the Shenzhen Bay. As a result, the velocity of the tidal current

关键词： reclamation environmental impact assessment Shenzhen Bay

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Classifying the sedimentary environments of the Xincun Lagoon,Hainan island,by system cluster and principal component analyses

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Acta Oceanologica Sinica 2017年第4期36卷 64-71页

作者： YANG Yang GAO Shu ZHOU Liang WANG Yunwei LI Gaocong WANG Yaping HAN Zhuochen JIA Peihong state Key laboratory for Estuarine and coastal Research East China Normal University Ministry of Education Key laboratory for coast and island development Nanjing University College of Harbour Coastal and Offshore EngineeringHohai University

An understanding of the sedimentary environment in relation to its controlling factors is of great importance in coastal geomorphology,ecology,tourism and aquaculture *** attempt to deal with this issue,using a case study from the Xincun Lagoon,Hainan island in southern *** the study,surficial sediment samples were collected,together with hydrodynamic and bathymetric surveys,during August *** simulation was carried out to obtain high-spatial resolution tidal current *** sediment samples were analyzed to derive mean grain size,sorting coefficient,skewness and kurtosis,together with the sand,silt and clay *** modern sedimentary environments were classified using system cluster and principal component *** size analysis reveals that the sediments are characterized by extremely slightly sandy silty mud（ESSSM） and slightly silty sand（SSS）,which are distributed in the central lagoon and near-shore shallow water areas,*** grain size varies from 0 to 8.0Ф,with an average of 4.6Ф.The silt content is the highest,i.e.,52% on average,with the average contents of sand and clay being 43% and 5%,*** exists a significant correlation between mean size and water depth,suggesting that the surficial sediments become finer with increasing water *** analyses reveals two groups of *** first group is characterized by mean grain size of more than 5.5Ф,whilst the second group has mean grain size of below 3.5Ф.Further,these groups also have different correlations between mean grain size and the other grain size *** terms of the tidal current,the average values of the root mean square velocity（RMSV） are 7.5 cm/s and 6.9 cm/s on springs and neaps,*** the RMSVs that are higher than 4 cm/s,a significant positive correlation is found between the content of the 63–125 μm fraction and the RMSV,suggesting that the RMSV determines the variability of the very fine sand *** on

关键词： surficial sediment grain size lagoon sedimentary environment statistical analysis numerical simulation Hainan island

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Impact of the cord-grass Spartina alterniflora on sedimentary and morphological evolution of tidal salt marshes on the Jiangsu coast,China

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Acta Oceanologica Sinica 2006年第4期25卷 32-42页

作者： WANG Aijun GAO Shu JIA Jianjun Open laboratory of Ocean coast Environmental Geology Third Institute of Oceanography State Oceanic Administration Xiamen 361005 China Ministry of Education Key laboratory for coast and island development Nanjing University Nanjing 210093 China Key laboratory of Submarine Geosciences Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

The tidal flats of the Wanggang area, on the Jiangsu coast, represent the largest continuously distributed coastal wetland in terms of area coverage in China, and the dynamics of tidal flat accretion and erosion is highly complicated. The cord-grass Spartina alterniflora, which was introduced artificially into the Jiangsu coast, has significant influences on the regional tidal flat evolution in terms of deposition rate, spacial sediment distribution patterns and tidal creek morphology. On the basis of the data set of bed elevation and accumulation rate for different periods of time, the applicability of the Pethick - Allen model to the Jiangsu tidal salt marshes is discussed. In addition, caesium-137 dating was carried out for sediment samples collected from the salt marsh of the Wangang area. In combination with the caesium-137 analysis and the data collected from literature, the Pethick - Allen model was used to derive the accumulation rate in the Wanggang tidal flat for the various periods. The results show that the pattern of tidal flat accretion has been modified, due to more rapid accretion following the iatroduction of S. alterniflora to the region. Surficial sediment samples were collected from representative profiles and analyzed for grain size with a laser particle analyzer. The result shows that fine-grained sediment has been trapped by the plant, with most of the sediment deposited on the Suaeda salsa and Spartina angelica flats being derived from drainage creeks rather than the from gently sloping tidal flats. Remote sensing analysis and in situ observations indicate that the creeks formed in the S. alterniflora flat have a relatively small ratio of width to depth, a relatively high density, and are more stable than the other tidal flat creek systems in the study area.

关键词： Spartina alterniflora tidal flat sedimentation morphological evolution Jiangsu coast

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Identifying sources and hazardous risks of heavy metals in topsoils of rapidly urbanizing East China

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Journal of Geographical Sciences 2016年第6期26卷 735-749页

作者：刘洋马宗伟吕建树毕军 state Key laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University The Key laboratory of coast and island development of Ministry of Education Nanjing University College of Population Resource and Environment Shandong Normal University

With rapid economic and social development, soil contamination arising from heavy metals has become a serious problem in many parts of China. We collected a total of 445 samples （0-20 cm） at the nodes of a 2 kmx2 km grid in surface soils of Rizhao city, and analyzed sources and risk pattern of 10 heavy metals （As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn）. The combination of Multivariate statistics analysis and Geostatistical methods was applied to identify the sources and hazardous risk of heavy metals in soils. The result indicated that Cr, Ni, Co, Mn, Cu, and As were mainly controlled by parent materials and came from natural sources. Cd and Hg originated from anthropogenic sources. Pb and Zn, belonging to different groups in multivariate analysis, were associated with joint effect of parent materials and human inputs. Ordinary Kriging and Indicator Kriging suggested that single element and elements association from the same principal components had similar spatial distribution. Through comprehensive assessment on all elements, we also found the high risk areas were located in the populated urban areas and western study area, which could be attributed to the higher geological background in the western part and strong human interference in the eastern part.

关键词： heavy metals in soils hazardous risk multivariate analysis Indicator Kriging Rizhao

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Analysis of the characteristics of offshore currents in the Changjiang(Yangtze River) estuarine waters based on buoy observations

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Acta Oceanologica Sinica 2017年第4期36卷 13-20页

作者： LI Peng SHI Benwei WANG Yaping QIN Weihua LI Yangang CHEN Jian Forecast Center for East China Sea State Oceanic Administration Ministry of Education Key laboratory for coast and island development Nanjing University Marine Environment Investigation Center of East China Sea State Oceanic Administration

A buoy of 10 m in diameter was used to record the current speed and direction in a vertical profile in the offshore area of the Changjiang（Yangtze River） Estuary（with an average water depth of 46.0 m） for one *** results include：（1） the currents rotate clockwise and the current direction is consistent in a vertical profile without clear seasonal variations.（2） The horizontal current speeds are generally high,with a maximum of 128.5 cm/s occurring in summer and 105.5 cm/s appearing in winter commonly close to the *** average current speeds in the vertical profile fall in the same range（the differences are less than 8.0 cm/s）,with the maximum of47.0 cm/s occurring in summer and 40.8 cm/s in *** average current speed during spring tides is twice that during neap tides（26.5 cm/s）.（3） Significant differences of speeds are observed in the vertical *** maximum current speed occurs at either surface（spring and winter） or sub-surface（summer and autumn）,with the minimum current speed appearing at the *** maximum average current speed of all layers is 57.9cm/s,which occurs in the 18-m layer during summer.（4） The average speed of the residual currents ranges from7.5 cm/s to 11.3 cm/s,with the strongest occurring in spring and weakest in *** residual currents of all layers are eastward during spring and winter,whereas northeastward or northward during summer and autumn.（5） The currents in the offshore of Changjiang Estuary are impacted collectively by diluted Changjiang River discharge,the Taiwan Warm Current,monsoon and tides.

关键词： ocean currents buoy observation seasonal variations Changjiang(Yangtze River) Estuary

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ENVIRONMENTAL CHANGES SINCE LATE PLEISTOCENE IN ESTUARINE PLAIN OF JIULONG RIVER, FUJIAN PROVINCE

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Chinese Geographical Science 1997年第4期7卷 375-382页

作者：陈文瑞蓝东兆陈承惠朱大奎 state pilot laboratory of coast & island Exploitation Nanjing University Nanjing P.R. China Third Institute of Oceanography National Bureau of Oceanography Xiamen P.R. China

Based on the evidences of lithostratigraphy, palynology, micropaleontolopy and geochronology, paleoenvironments since the Late Pleistocene in the study area have been reconstructed. One of the most important inferences is that two marine transgressions have occurred, one in Wurm Sub-interglacial and the other Postglacial. The former had caused the study area to be in an estuary-bay envirment over the transgression maximum, with a sea level of no less than 10 m below present; foe latter reached its maximum over the Atlantic stage, with sedimentary environments of estuary-bay, hay or shallow sea, and the sea level arrived at the highest elevation in about 6 - 5 ka B.P. Furthermore, it is notable that, during the Late Wurm Glacial, the study area area had principally been in an estuary-bay environment, although the climate, like many other areas, turned cold and dry, It reflects a general trend of crustal subduction in Jiulong Estudrine Plain over this pened.

关键词： environmental change Late Pleistocene Jiulong Estuarine Plain Fujian Province

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High-resolution data collection for analysis of sediment dynamic processes associatedwith combined current-wave action over intertidal flats

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Chinese Science Bulletin 2006年第7期51卷 866-877页

作者： WANG Yaping GAO Shu JIA Jianjun Key laboratory for coast and island development Ministry of Education Nanjing University Nanjing 210093 China Key laboratory of Submarine Geo-Sciences Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

An MIDAS-400 Customised Data Ac- quisition System was deployed to obtain current ve- locity and suspended sediment concentration profiles over the intertidal flat at Wanggang, on the Jiangsu coast (China). At the same time, seawater tempera- ture, conductivity and pressure were measured. Us- ing a data sampling rate of 4 Hz, the high-frequency pressure signals in response to water surface fluc- tuations were recorded and subsequently trans- formed into wave parameters. The analytical results show that the apparent bed roughness length has a magnitude close to the height of sand ripples, which is much larger than the grain size diameter. The bot- tom shear stress associated with current-wave in- teraction is higher than the tidally-induced stress and intensified turbulent mixing and resuspension. Fur- thermore, several suspended sediment concentration peaks occurred during a tidal cycle, which can be related to strong turbulence near the bed caused by frontal tidal currents and the enhanced resuspension; advection and extreme weather conditions (e. g. storms and strong winds) also played an important role. Finally, large net suspended sediment fluxes were observed to present when the flood or ebb currents prolonged, i.e. the flow became quasi-unid- irectional during a tidal cycle. In general, the MIDAS- 400 is a suitable tool for high-resolution data collec- tion for the situations of combined current-wave ac- tion over intertidal flats; the data obtained can be used to analyze the processes and mechanisms of material transport.

关键词：高分辨率数据收集底板压力悬浮沉积浓缩潮间带

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