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1.
潮滩剖面形态与多组分泥沙分选是海岸动力学与河口、海岸地貌学的重要研究内容,对保持生物多样性、研究沉积历史和沿海工程评估等具有重要的实际意义。从现场观测、理论解析和数值模拟等方面,归纳了在潮滩剖面形态特征与多组分泥沙分选方面研究的主要进展。回顾了潮滩剖面形态分别在潮流和波浪主导下的经典理论解析解,剖析了包括潮流、波浪泥沙来源及特性等主要影响因子以及植被、海平面上升、围垦工程等其他影响因子对潮滩剖面形态水平向、垂向泥沙分选过程的作用机理,同时提出了考虑水动力、生物作用、人类活动等多因子耦合作用下潮滩演变研究以及定量化预测方向的若干亟待解决的科学问题。 相似文献
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The swing of the main channel of the Qiantang River is controlled by the high-water and low-water changes in the river, as well as the impact of large-scale reclamation of tidal flats. Its evolution in modern times is the result of the combined functions of natural and man-made factors. This paper analyzes the cause of the formation of the South Channel and Xisan Tidal Furrow and proposes the regulation principle of “To regulate the river and reclaim tidal flats by taking the advantage of local topography”. It is suggested to cut off the South Channel and Xisan Tidal Furrow completely to restrict the swing of the main channel and to increase the reclamation area of the tidal flat at the same time. 相似文献
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Qingguang Zhu Ya Ping Wang Wenfei Ni Jianhua Gao Minliang Li Lei Yang Xulong Gong Shu Gao 《Environmental Earth Sciences》2016,75(23):1472
Intertidal (tidal flat) reclamation along the Chinese coastline, especially which is in Jiangsu Province, has increased markedly in recent years. However, the hydrodynamic disturbance and environmental impacts of this activity are not yet fully understood. In this study, a process-based depth-averaged model is used to evaluate quantitatively the possible impacts of intertidal reclamation for the southern Yellow Sea region. The simulation results show that reclamation of both inshore and offshore intertidal areas of ~1800 km2 (according to the approved governmental reclamation scheme) would result in three remarkable changes in tidal patterns: enhanced M2 and M4 tidal amplitudes in coastal areas, strengthened negative tidal asymmetry in the southern region of the sand ridge system, and an enhanced tidal energy flux toward offshore through the main channels in the south. These changes would result in some negative impacts. The enhancement in local tidal amplitude could increase the probability of coastal hazards, and the offshore sediment transport tendency resulting from negative tidal asymmetry in the south could lead to severe erosion. The enhanced energy flux transported offshore may also affect far-field regions. On the other hand, alternative reclamation of ~400 km2 of offshore intertidal area could significantly minimize hydrodynamic disturbances to the local tidal system. Offshore reclamation with lower environment impacts may be the future for coastal development. To cope with the potential environmental risks caused by reclamation, it is recommended to strengthen environmental impact assessment and overseeing of reclamation plans, and advance international cooperation in terms of coastal management. Our findings provide a reference for coastal management in countries with substantial areas of tidal flats. 相似文献
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为研究多因子共同作用下的潮滩演变机制,开发了基于植被生长和潮动力作用的潮滩剖面演变数学模型。在不考虑植被作用下,模拟得到了潮滩中长期演变后的上凸形剖面特征;泥沙供给是决定潮滩宽度的因素,供给越充分,潮滩宽度越大。模型考虑植被过程时,结果表明不同的植被生物量分布形式对潮滩水动力的影响程度不同,在潮间带上部,生物量抛物线分布时的减流效果强于生物量线性分布形式;而在潮间带下部则相反。模拟结果显示盐沼和光滩之间出现陡坎,且随着滩面的逐步淤高,陡坎逐步向海移动。 相似文献
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为揭示河口湾水动力环境对滩涂利用的累积响应过程,以珠江口伶仃洋河口湾为例,基于潮波数学模型和潮流数学模型,研究了1981年以来湾内进出潮量、分潮振幅和潮流流速的累积变化。结果表明:相对于1981年,2018年岸线条件下伶仃洋湾口断面涨落潮量累积减少4.9%~6.0%、内伶仃断面涨落潮量累积减少9.0%~12.8%、深圳湾断面涨落潮量累积减少17.8%、南沙断面涨落潮量累积减少5.0%~6.3%;伶仃洋M2分潮振幅呈增加趋势,振幅增幅由南向北增加,潮波由南向北变形进一步加剧;伶仃洋最大可能潮差变化与M2分潮振幅变化趋势一致,潮汐性质没有发生变化;伶仃洋潮流流速总体减小,西岸流速减幅高于东岸,湾顶附近流速略有增加。 相似文献
7.
盐沼潮滩作为滨海湿地的一个重要类型,为河口海岸地区提供了多种关键的生态服务功能,具有重要的社会、经济与生态价值,其地貌演变规律的认知是海岸带保护修复和科学管理的基础。回顾国内外近一个世纪以来针对潮滩动力地貌过程的研究工作,发现研究热点已逐渐从传统的研究潮滩水-沙-地貌相互作用过渡到探索植物、动物、微生物等生物作用与动力、地貌之间的互馈机制,涉及海岸动力学、地貌学、沉积学、环境生态学等多个学科,是典型的交叉学科前沿研究领域。归纳了盐沼植被与潮滩多种因子的相互作用,总结了常用的盐沼潮滩地貌演变模拟手段及取得的机理认知,并提出今后在生物作用、陆海耦合动力地貌模型研发等方面的科学问题和发展方向。 相似文献
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以实地调研资料为依据,对苏中黄海岸带的侵蚀、淤积作出系统分析。将苏中岸段分为北侵蚀、南淤积两大段,射阳河口以北的面大套河口为侵、淤转换中介点。作者从地貌形态、地层岩性(结构构造为主)、入海河口与风浪组合的水动力条件着眼,对侵、淤形成机制作了简要分析,并对发展趋势作出了概略预测,最后针对岸带侵、淤特点,提出岸带保护措施及滩涂资源开发利用方向。本文可供海岸滩涂资源开发利用规划及地质灾害防治参考利用。 相似文献
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深圳是我国经济高速发展的海滨城市。最近20年城市发展中对海洋资源开发已取得巨大成就,特别在 海港建设、围海造地开拓城市用地空间等方面。文章是配合深圳城市发展建设,从海岸海洋环境资源的调查分析 着手,对海岸带利用作出空间规划。 深圳西岸是珠江口冲积平原,正处珠江河口区的最大浑浊带范围,泥沙淤积使岸线外移,是深圳海涂资源主要 分布区。至2000年深圳在海涂区已围海造地26.8km2,按规划至2010年,将再填海28km2。西岸的填海已影响到 珠江口深槽淤积、浅滩扩大及深圳湾污染加重。至2010年,预期围海工程完毕后,已达海涂开发与海洋环境容量 的极限,今后不能再围海造地。 深圳是中国南方主要外贸进出口港,可能会发展成与上海并列为中国的两个国际航运中心。2020年运量将超 过2亿吨,西岸深水港发展将饱和,深圳深水港后备基地将在东部海岸,大鹏湾东岸下沙、南澳沿岸是理想的大型 深水港后备基地。 利用深圳河及开凿梧桐山,贯通大鹏湾与深圳湾,这一深圳运河工程是改善深圳湾海洋环境、根治深圳河污染 的重要生态工程,同时还具有航运与旅游功能。 相似文献
10.
利用在长江口崇明岛北支北四滧港（SY）、北堡港（BBG）以及新卫村（XW）潮滩获取的表层沉积物,测试总有机碳（TOC）、总氮（TN）及总硫（TS）含量,分析有机地球化学元素在潮滩微相的分布规律及影响因素,试图建立TOC/TN、TS/TOC等潮滩微相识别指标。研究结果显示,影响长江口潮滩TN、TS微相分布的重要因素为有机质含量及类型。在淤涨型潮滩,TOC/TN在高潮滩一般大于10,在中潮滩明显降至10以下;中潮滩植被带TS/TOC最高,平均值达0.063,其次为高潮滩互花米草带和中潮滩光滩（分别为0.055和0.054）,高潮滩芦苇带最低;TS-TOC一元线性回归斜率在高潮滩芦苇带呈现为显著低值,自高潮滩米草带向光滩,逐渐增大。在侵蚀型潮滩,TOC/TN从高潮滩到低潮滩均大于10,而且中、低潮滩的比值大于高潮滩,潮下带骤降至小于10;TS/TOC自陆向海逐渐增大,TS-TOC一元回归斜率高潮滩最低,中潮滩最高。另外,侵蚀型潮滩各微相的TS-TOC一元线性回归斜率均明显低于淤涨型潮滩。上述研究结果表明,长江口沉积物的TOC/TN和TS/TOC及TS-TOC一元线性回归斜率与潮滩沉积微相之间存在一定的关系,具有应用于全新世钻孔识别潮滩沉积物微相的潜力。 相似文献
11.
潮滩沉积物重金属累积特征研究进展 总被引：21，自引：1，他引：21
在分析总结国内外潮滩重金属研究现状和成果的基础上，指出潮滩重金属来源的定量分析尚很不完整；沉积物的物质组成、粒径、水动力作用、潮滩生物、河流输入量、人类活动等都对重金属在潮滩的分布有着重要影响。在垂岸方向，重金属从高潮滩到低潮滩含量逐渐降低，反应了水动力以及粒径对潮滩重金属的分布的控制；沿岸方向，淤涨岸段，重金属含量低，排污口严重影响着重金属的沿程分布，重金属含量随离排污口的距离增大而呈指数减少；垂向方向，在许多地方重金属分布与人类活动、经济发展状况相吻合。生物活动使潮滩重金属的累计特征变得复杂，改变了潮滩局部的微环境。与国内外河口重金属研究相比，潮滩重金属的研究远远不足。沉积物中重金属常用研究方法，如Tes sier地球化学相连续提取法、Meso cosm模型，以及数值和现场模拟的方法的应用，对潮滩重金属的研究将有很大帮助。在潮滩重金属的污染评价中，生物标准较其它标准更为适合。 相似文献
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A unique radial tidal sand ridge system (RTSRS) has developed under a complex tidal current field on the eastern China coast
between the Yangtze River delta to the south and the abandoned Yellow River (Huanghe) delta to the north. The present study
examines the sedimentary evolution of a ridge-channel pair in the central RTSRS. Three cores, with two on the ridges and one
in the channel, were drilled to reveal the late Pleistocene-Holocene deposits of the system. Five sedimentary facies were
distinguished, i.e. ridgeshallow subtidal facies, ridge-deep subtidal facies, nearsurface channel bottom facies, middle tidal
flat facies and low tidal flat facies. The ridge-shallow subtidal facies consists of sandy strata with ripple cross beddings,
horizontal lamina, and massive beddings. Bioturbation seldom occurs. The ridge-deep subtidal facies is primarily characterized
by sandy and muddy interlayers with common flaser and lenticular bedding structures. Bioturbation appears abundantly. Massive
and graded sediment sequences of storm origin are present as characterized by rich shell fragments. The nearsurface channel
bottom facies consists of loose, soft, clayey silt deposits with deformed sedimentary layers. This facies occurs in the deeper
part of the active channels. The middle tidal flat and lower tidal flat facies composed of silt-clay couplets prevailed primarily
in the tidal flats. Incomplete sedimentary successions show that coastal plain deposits dominate in the study area during
12–13 ka B.P. The sandy ridge and channel facies became dominant during 4–6 ka B.P. when the sea level receded temporarily.
Tidal ridge and channel in the study area became active during the last four decades. Sediment reworking due to typhoon and
sandy ridge migration plays a key role in shaping the present radial ridge system. 相似文献
13.
A. Chakrabarti 《Journal of Earth System Science》2005,114(3):353-368
Sedimentary structures of some coastal tropical tidal flats of the east coast of India, and inner estuarine tidal point bars
located at 30 to 50 kilometers inland from the coast, have been extensively studied under varying seasonal conditions. The
results reveal that physical features such as flaser bedding, herringbone cross-bedding, lenticular bedding, and mud/silt
couplets are common to both the environments. In fact, flaser bedding and lenticular bedding are more common in the point
bar facies during the monsoon months than in the coastal tidal flat environments. Interference ripples, though common in both
the environments, show different architectural patterns for different environmental domains. Interference ripples with thread-like
secondary set overriding the earlier ripple-form, resembling wrinkle marks, are the typical features in estuarine point bars
near the high water region. Because structures which are so far considered as key structures for near-coastal tidal flats
are common to both the environments, caution should be exercised for deciphering palaeo-environments, particularly for Proterozoic
rocks, where one has to depend only on physical sedimentary structures. 相似文献
14.
有效识别和评估各滩涂区域资源开发承载力时空变化的差异, 有利于滩涂资源的科学规划, 对实现沿海滩涂资源的高效利用与保护具有重要意义。本文针对渤海半封闭海湾滩涂特征的空间差异性, 基于"驱动力-状态-影响"模型, 构建了滩涂资源开发承载力评估体系, 对研究区域7个评价单元在4个代表年份的资源承载力进行了评估, 阐明了海湾滩涂资源开发承载力时空演变特征。结果表明: 围填工程减弱了渤海湾滩涂资源开发承载能力, 工程大规模建设期间(2003—2012年)各评价单元承载力均呈下降趋势, 2012年后随着国家围填海管控措施的实施, 滩涂承载力有回升态势; 在空间上滩涂资源承载力表现为湾顶的降幅高于海湾南部区域, 滩涂开发前后天津港附近区域承载力较弱, 黄骅港以南滩涂养殖区承载力较强。 相似文献
15.
基于RS与GIS的南汇东滩围垦研究 总被引：1，自引：0，他引：1
RS和GIS技术是滩涂围垦监测最经济和有效的方法之一。本文基于1983年以来多期遥感影像,解译出了不同时期人工岸线的位置,在此基础上利用GIS技术分析了近30年来南汇东滩的围垦过程及其与滩涂淤涨速率的关系。结果表明,近30年来南汇东滩的围垦过程呈现＂由慢至快＂的发展趋势,经历了＂缓慢—稳步—高速＂三个发展阶段：（1）1983～1995年年均围垦速率约1.23km2/a,圈围速率较小;（2）1995～2000年为7.95km2/a,围垦速率处于稳步增长阶段;（3）2002～2005年为35.27km2/a,是围垦速率最大的阶段。2002年以前,围垦速率与滩涂淤涨速率基本一致,2002年之后,围垦速率远大于滩涂淤涨速率。本文认为8km2/a是南汇东滩适宜的围垦速度。2002年之后南汇东滩的快速围垦并没有导致上海整体滩涂面积的减少,围垦可不囿于局部滩涂面积的稳定,以全市总体滩涂面积和湿地水平的动态平衡,可为滩涂资源开发利用提供现实选择。 相似文献
16.
苏北潮滩湿地不同生态带碳、氮、磷分布特征* 总被引：1，自引：0，他引：1
通过对比苏北潮滩湿地不同生态带的表层以及柱状沉积物中总有机碳、总氮、总磷和有机磷含量,并结合不同植被不同植株部位中碳、氮、磷的含量变化,分析了潮滩沉积物中碳、氮、磷的垂向和水平分布特征与规律,探讨了不同生态带以及潮滩植被对碳、氮、磷等生源要素的富集作用。对比分析结果表明:苏北潮滩湿地各生态带对不同的测量指标有着不同的富集作用,互花米草滩的总有机碳、总氮和有机磷含量要远大于其他几个生态带,光滩沉积物中总磷的含量最高; 粒度效应是控制互花米草前缘地带以及互花米草滩沉积物中有机碳和氮分布的一个重要因素,盐蒿和芦苇滩中有机碳和氮的分布更多的是受粒度之外的其他因素影响; 不同生态带表层沉积物中的C/N比值分布,大致可反映其有机物来源的差异,而不同生态带中柱状沉积物中的C/N比值相对接近,很难根据C/N比值大小来对不同生态带中的有机物来源进行判断,这可能是埋藏在柱状沉积物中的有机物更多的受到了早期成岩作用造成的。植被对潮滩湿地中碳、氮、磷的分布有着重要影响,3种物质在互花米草、盐蒿和芦苇中的含量差别不是很大,因此潮滩植被对沉积物中上述3种物质的贡献差别主要是由不同植被的生物量和其所处环境的沉积动力差异造成的。 相似文献
17.
Microbial deposits at Shark Bay constitute a diverse living microbial carbonate system, developed in a semi‐arid, highly evaporative marine setting. Three tidal flats located in different embayments within the World Heritage area were investigated in order to compare microbial deposits and their Holocene evolution. The stressing conditions in the intertidal–subtidal environment have produced a microbial ecosystem that is trapping, binding and biologically inducing CaCO3 precipitation, producing laminated stromatolites (tufted, smooth and colloform), non‐laminated thrombolitic forms (pustular) and cryptomicrobial non‐laminated forms (microbial pavement). A general shallowing‐upwards sedimentary cycle was recognized and correlated with Holocene sea‐level variations, where microbial deposits constitute the younger (2360 years bp ) and shallower sedimentary veneer. In addition, sediments have been documented with evidence of exposure during the Holocene, from 1040 to 940 14C years bp , when sea‐level was apparently lower than present. Filamentous bacteria constitute the dominant group in the blister, tufted and smooth mat types, and coccus bacteria dominate the pustular, colloform and microbial pavement deposit types. In the subtidal environment within colloform and pavement structures, microbial communities coexist with organisms such as bivalves, serpulids, diatoms, green algae (Acetabularia), crustaceans, foraminifera and micro‐gastropods, which are responsible for exoskeleton supply and extensive bioturbation. The internal fabric of the microbial deposits is laminated, sub‐laminar, scalloped, irregular or clotted, depending on the amount of fine‐grained carbonate and the natural ability of microbial communities to trap and bind particles or induce carbonate precipitation. Nilemah tidal flat contains the thickest (1·3 m) and best‐developed microbial sedimentary system; its deposition pre‐dated the Rocky Point and Garden Point tidal flats, with the most positive isotope values for δ13C and δ18O, reflecting strong microbial activity in a highly evaporative environment. There is an evolutionary series preserved within the tidal flats reflecting relative ages and degree of salinity elevation. 相似文献
18.
Sourav Saha Anupam Ghosh Santanu Banerjee Pratul K. Saraswati Stuart D. Burley 《Journal of the Geological Society of India》2011,77(5):409-418
This study highlights lithofacies and biofacies characteristics of the open coast tidal flat near Daman on the eastern flank
of Gulf of Khambhat. Sedimentological and biological observation record six facies within the tidal flat area including older
beach, beach face, sand flat, mud flat/mixed flat, sand bar and beach rock. Distinct sedimentary structures, foraminiferal
assemblage and bioturbation intensity characterize each facies. A wide variety of wave and current generated sedimentary features
characterize the sand flat facies. Semiconsolidated sands of older beach running parallel the coastline at a level higher
than the present beach face possibly records the latest sea level highstand. The beach rock reflects early cementation of
sands in tropical environments. Foraminifera are widely distributed in sand flats, mixed flats and mud flats and grouped into
two biofacies — Ammonia-Elphidium-Quinqueloculina biofacies (sand flat and mixed flat) and Trochammina-Miliammina biofacies (mud flats). The beach face and sand bar facies contain forminifera reworked from sand flat and mud/mixed flat.
Seasonal variation in depositional style is marked by deposition of fresh mud deposited over large areas of the intertidal
flat during monsoon time, most of which is washed away by waves and current actions well before the onset of the next monsoon. 相似文献
19.
本研究通过对长江口现代潮滩6个柱状样沉积物的粒度精细分析,试图提取研究区潮滩沉积相识别的粒度敏感指标,并通过对长江三角洲南部平原一个全新世钻孔(SL67孔)潮滩沉积物的粒度研究,检验现代沉积粒度敏感指标在全新世钻孔潮滩沉积相识别中的应用。研究显示,长江口现代高潮滩和中潮滩的黏性颗粒(8μm)和粗粉砂(32~63μm)含量差异显著,可以成为区分高潮滩和中潮滩的敏感组分;在开敞型的中、低潮滩之间,砂(63μm)和细粉砂含量(8~32μm)也差异明显。长江口现代潮滩沉积物的粒度频率曲线及众数值也可以有效协助区分高潮滩、中潮滩和低潮滩沉积物。利用上述粒度敏感组分和众数指标检验SL67孔全新世早中期在海平面波动控制下的潮滩演替过程,并揭示了7.5 cal ka BP前后的一次海平面加速上升事件。 相似文献
20.
潮滩生态系统中生源要素氮的生物地球化学过程研究综述 总被引：2，自引：1，他引：1
海岸带潮滩生源要素生物地球化学循环过程是国际地圈生物圈计划（IGBP）、海岸带陆海交互作用（LOICZ）研究的重要内容,也是全球变化区域响应研究中的重要组成部分。在过去的10～20年之间,潮滩生源要素氮的生物地球化学循环研究得到了长足的发展。基于此,较为全面、系统地总结和分析了有关潮滩氮营养盐的来源、潮滩氮素的物理、化学和生物迁移转化过程及氮素地球化学循环过程中底栖生物效应等一系列研究成果,并提出了今后潮滩生源要素氮的生物地球化学循环研究重点和发展趋向。 相似文献