广东省海岸侵蚀现状及影响因素分析

20世纪50年代以来,广东海岸蚀退现象比较明显,本文基于广东省海岸侵蚀全面系统的调查,描述了广东省海岸侵蚀现状,进行了侵蚀强度分类及分布规律统计;总结分析不同海岸侵蚀类型的特征及差异;通过分析影响海岸侵蚀灾害的因素认为,广东海岸侵蚀是自然因素和人为因素共同作用下产生的,人类活动是近代海岸侵蚀加剧的主要原因。本研究将有助于广东省海岸带减灾、防灾目标的实现,为海岸侵蚀灾害的进一步研究打下基础。     

海岸侵蚀作用下海岸带地区极端风暴洪水风险评估 —以上海石化为例

海堤是海岸带地区社会经济活动的重要保护屏障。海岸侵蚀的加剧将导致海堤稳定性和安全性降低, 增加海岸带地 区遭受极端风暴洪水的风险, 进而影响到海岸带地区的安全。本文选择上海石化这一遭受海岸侵蚀较为严重的区域作为研究 区, 利用 GIS 分析了 1972—2020 年近岸海床侵蚀特征, 并基于 2000—2020 年-5 m 等深线变化评估了上海石化近岸海堤的 稳定性。结果表明： 1972—2020 年间上海石化前沿海床整体以侵蚀为主, 石化近岸东侧以及西侧局部的浅滩侵蚀明显, 城 市沙滩中段、第 6 次围堤处以及码头东岸海堤稳定性最低。基于上述研究结果, 考虑海堤稳定性薄弱段出现极端风暴洪水漫 堤或溃堤情景, 模拟并分析了上海石化 2010 年 、2030 年和2050 年遭受千年一遇极端风暴洪水的风险。结果显示： 在 2010 年基准年情景下, 受海岸侵蚀作用最明显的城市沙滩和第6 次围堤区域遭遇极端风暴洪水的风险最高, 到 2050 年, 当前稳 定性较好的海堤安全性也将大大降低, 与 2010 年相比, 上海石化近岸地区的直接经济损失将会增加近 3 倍。     

Promoting resilient economies by exploring insurance potential for facing coastal flooding and erosion: Evidence from Italy,Spain, France and United Kingdom

Insurance against natural perils such as flooding can be considered a significant element in coastal management. It can offer not only much-needed support to accelerate economic and social recovery following a disaster (coastal resilience) but also contribute to impact limitation by using pricing or restrictions on availability of coverage to discourage new development in hazard-prone areas. Insurance can affect the redistribution of damage costs across the population and through time, both in the short and long term. Policies of damage reduction are linked to mitigation measures for the properties (old or new buildings) by changing the depth–damage relationship while the long-run risk impacts could affect the overall damage function by discouraging new buildings in high risk areas. This paper will provide an overview of the main theoretical perspectives on insurance in flood risk management. Four different European contexts will be analysed. Data are derived from surveys and interviews conducted in France, United Kingdom, Italy and Spain.     

Implementation of coastal erosion management in the Netherlands

The Netherlands is a low-lying country, in which 9 million people are living below sea level and 70% of the gross domestic product is being earned in areas below sea level. Therefore, protection against flooding is traditionally the primary focus of coastal policy in the Netherlands. Analysis shows that characteristics of Dutch coastal management very well comply with the recommendations and key concepts to support sustainable coastal management as issued by the EU in 2004 (EUROSION). Sediment management represents the core of erosion management in the Netherlands; key concepts like resilience, coastal sediment cells, favorable sediment status and strategic sediment reservoirs, are important building stones. Development and implementation of coastal erosion management in the Netherlands, has implicitly been guided by a systematic Frame-of-Reference. Characteristics of this approach are the definition of clear objectives at different levels (i.e. strategic, tactical and operational) and an operational decision recipe related to policy development and implementation. Application of the Frame-of-Reference to current problems and challenges in Dutch coastal management indicates its ability to reveal shortcomings of the existing approach, and to explore potential solutions. Where EUROSION offers important concepts to define coastal erosion management, the Frame-of-Reference offers a tool to discern different objectives and responsibilities. The combination of both strongly supports implementation of coastal erosion management.     

The role of coastal setbacks in the context of coastal erosion and climate change

Coastal erosion and storms represent a source of risk for settlements and infrastructure along the coast. At the same time, coastal natural assets, including landscape, are threatened by increasing development mainly driven by tourism. The Mediterranean coast is especially vulnerable to these processes, considering its high biological and cultural diversity. An additional challenge is represented by climate change, as it will force coastal communities to apply more or less drastic adaptation strategies. Coastal setbacks, used to protect coastal communities and infrastructure from storms and erosion, and to preserve coastal habitats and landscapes from degradation, is one of the main instruments suggested by the Protocol on Integrated Coastal Zone Management of the Barcelona Convention, entered into force on the 24 of March 2011. Its implementation has the potential to influence coastal policies in other regions, such as the neighbouring Black Sea.The CONSCIENCE project has formalized concepts and conducted specific studies to provide new tools for coastal erosion management practice. The objective of this paper is to present a synthesis of the research conducted into coastal setbacks for coastal erosion management and climate change adaptation. This is done by analysing the requirement of the Protocol, current processes and management practices in two case study areas (Costa Brava Bays in Spain and Danube Delta, in Romania) and the new challenges posed by climate change.     

Analyzing qualitative and quantitative changes in coastal wetland associated to the effects of natural and anthropogenic factors in a part of Tianjin,China

Natural and anthropogenic factors in coastal wetland changes are widely discussed in wetland studies. Previous literatures have demonstrated that many factors may cause wetland change and argued that the global climate change and nutrient enrichment may become the most important ones in the next 50 years. Through field investigation, with the help of remote sensing technology and geographic information system, this research discusses the wetland change in Tianjin under the great pressure of rapid economic development, population growth, and sea-level rising. These findings include: (1) the wetland area expanded from 466.50 km² to 658.38 km² between 1987 and 1998, but it shrank to 550.5 km² by the year of 2006. (2) The results show that the groundwater has not been contaminated while the surface water has been polluted. (3) The questionnaire survey shows that the social environment in some specific ways impedes the protection of natural reserve. In order to achieve the harmony between human and nature, feasible countermeasures on how to keep ecological balance should be immediately taken. Consequently, natural conservation and sustainable economic development will be realized.     

Assessment of coastal flooding hazard along the Emilia Romagna littoral,IT

Aim of this paper is to develop simple tools for mapping — at regional and local scale — coastal areas exposed at flooding risk. A two-step simplified procedure for coastal management purposes is presented and is applied to Emilia Romagna (Italy), whose low and sandy coast faces the relatively mild Northern Adriatic Sea. The procedure is composed by a 1D conceptual model to determine flooding probability along wide coastal stretches and by a more detailed 2D Level II reliability method, that provides local quantitative statistical maps of inland flooding propagation. Qualitative maps obtained by literature approaches and quantitative results of flooding probability along the littoral show a good agreement. A coastal flood state indicator is proposed to rapidly assess coastal hazard.     

Biological indicators in the Caribbean coastal zone and their role in integrated coastal management

Caribbean coastal ecosystems are increasingly being threatened by natural and anthropogenic factors. The scale of these factors is at local, national, regional and global levels. Threats include the effects of fisheries and extraction, eutrophication, siltation, and pollution as well as global climate events such as El Niño and global climate change. Integrated coastal management (ICM) should clearly demonstrate the adverse effects of environmental impacts, thus justifying the need for mitigation and should evaluate the success of management efforts. ICM requires robust indicators that gauge the ‘health’ of the coast in relation to environmental, social and economic activities. Biological indicators (bioindicators) offer a signal of the biological condition in an ecosystem. Using bioindicators as an early warning of pollution or degradation in an ecosystem can help sustain critical resources. Biological indicators in the Caribbean are focused around particular ecosystems, especially coral reefs, seagrass beds and mangrove forests and include a range of biological parameters relating to particular species, groups of species and biological processes. The use of these indicators is critically reviewed and the presence or absence of a relevant framework for their use in Caribbean ICM programs is discussed.     

Phytoplanktonic biogeography in the subtropical coastal waters,East China Sea along intensive anthropogenic stresses: roles of environmental versus spatial factors

Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants that driving the biogeography of phytoplankton communities in the coastal area of northern Zhejiang still remained unclear. We surveyed phytoplankton community compositions in water columns associated with environmental and spatial influences across five subzones that geographically...     

福建海岸侵蚀风险评价研究

海岸侵蚀和淤积一直存在于海岸带系统内并塑造着现在的海岸线,近年来不当的人类活动以及全球气候变化加剧了海岸侵蚀,导致沿海土地流失,威胁人类生命财产安全。本文构建了海岸侵蚀风险评价理论体系,阐述了海岸侵蚀风险评价的方法,为海岸侵蚀风险管理提供有效指导。运用层析分析法确定评价指标权重;根据模糊集理论合成海岸侵蚀风险等级。以福建省海岸带为例,进行了海岸侵蚀风险评价,编绘了风险评价图,评价结果与客观情况比较吻合,验证了文中理论方法的适用性。本文构建的海岸侵蚀风险评价理论体系可以推广到其他区域,但应根据实际情况适当调整指标个数以及指标权重。     

Rates of coastal erosion and accretion in New Zealand

Abstract

Rates of coastal erosion and accretion for New Zealand are calculated for the period since early European colonisation. Methods used for calculating rates from cadastral plans, vertical aerial photographs and field measurements are described, evaluated, and illustrated with examples. The most natural reference line for measurements of shoreline changes and for defining the seaward boundary of land is the seaward limit of land vegetation. Measurements made from air photographs and plans at scales larger than 1:4000 have errors less than ± 1 m. As scales become small, errors increase proportionately. Along depositional shorelines, erosion and accretion generally occur at 0.5–4.0 m.y^?1. Maximum erosion and accretion rates are 25.4 m.y^?1 at North Kaipara Head and 68.9 m.y^?1 at Farewell Spit respectively. Cliff recession generally occurs at 0.25 ‐ 1.0 m.y^?1 with maximum rates of 2.25 m.y^?1 for mudstone cliffs at Cape Tumagain and 3.46 m.y^?1 for conglomerate cliffs at Ngapotiki.     

The impact of extreme flooding events and anthropogenic stressors on the macrobenthic communities’ dynamics

Marine and coastal environments are among the most ecologically and socio-economically important habitats on Earth. However, climate change associated with a variety of anthropogenic stressors (e.g. eutrophication) may interact to produce combined impacts on biodiversity and ecosystem functioning, which in turn will have profound implications for marine ecosystems and the economic and social systems that depend upon them.     

Approaches to knowledge sharing and capacity building: The role of local information systems in marine and coastal management

This paper explores how coastal data and information can be mobilised in information systems and applied in coastal management. The concept of an Information System is defined and described, and the potential role of Local Information System (LIS) in integrated coastal management (ICM) is considered. Three examples, from the Severn Estuary, UK the coast of the North West of England and North Wales, and the Fal and Helford estuaries, are used to demonstrate the requirements of a LIS for coastal areas. The role of GIS as part of the solution is considered in detail. The paper demonstrates how ideas from the disciplines of information systems and information science can be practically applied in coastal areas. The findings promote a holistic approach for those involved in the development of technologies and dealing with data and information about coasts and oceans.     

辽宁省海岸的蚀淤等级与分布

为了查清辽宁省海岸的蚀淤等级和分布,从1990年和2007年遥感图像中提取了17年的岸线变化信息,结合辽宁省908专项海岸带海岸侵蚀特征的调查资料,对全省海岸蚀淤情况进行了等级划分,并对其形成原因进行了分析与评价。结果表明,砂质海岸侵蚀较重的区域主要分布在绥中和熊岳一带,黄海岸段的砂质海岸基本稳定,基岩海岸侵蚀较重的区域主要分布在老铁山一带,粉沙淤泥质海岸侵蚀较重的区域分布在庄河一带。摸清辽宁省海岸蚀淤等级分布,对海岸整治与修复、海岸侵蚀灾害的防治与防护以及海岸带管理具有一定的指导意义。     

Geochemical and stratigraphic indicators of late Holocene coastal evolution in the Gythio area, southern Peloponnese, Greece

The study of past changes in sea level, and of historical and pre-historical coastal evolution, using coastal sediment stratigraphies is well-established over a range of geographic areas, in both seismic and aseismic settings. In the eastern Mediterranean, however, such studies are less common, and, notably, the use of sediment geochemistry, and its combination with lithostratigraphic studies to analyze palaeoenvironmental and palaeo-sea-level change, has not been explored to any significant extent, despite the fact that geochemical data have been successfully used elsewhere to aid in the identification of sea-level changes. Here, we use a combined geochemical, stratigraphic and microfossil approach to reconstruct late Holocene coastal evolution and sea-level change at two sites near Gythio in the southern Peloponnese, Greece. The sites show stratigraphic and geochemical evidence of the presence in Late Helladic times (ca. 1500 BC) of barrier-protected coastal lagoonal/wetland environments, which have gradually infilled over the last ca. 3500 yr. Archaeological remains and ceramic and charcoal-bearing horizons within the sediment sequences indicate Late Roman occupation of the area, although there is no sedimentary evidence of significant pre-Roman activity at the study sites. An apparent brackish wetland peat deposit at − 3.4 m (overlain by anoxic lagoonal clays) at Kamares (Kato Vathi) Bay shows a calibrated radiocarbon age of 1640–1440 BC, suggesting a relative sea-level rise of 0.8–1 mm/yr in this area over the past 3500 yr, in good agreement with previous archaeological and sea-level modelling studies. There is no evidence, based on the stratigraphic, microfossil or geochemical record, of sudden marine flooding events related to local or regional seismic activity, despite the presence of the area in a seismically active zone known to be subject to periodic earthquakes and tsunami. The data highlight the utility of combining geochemical and stratigraphic studies in the reconstruction of coastal evolution and the study of palaeo-sea-level changes, particularly in sequences (such as those described here) where microfossils are poorly preserved.     

珠江口淇澳岛滨海湿地沉积环境演化及其对人类活动的响应

滨海湿地作为人类活动和全球变化反应最为敏感的区域,其沉积记录可以反映出周边地区环境变化及人类活动信息。珠江口淇澳岛滨海湿地钻孔分析结果表明,在中全新世期间淇澳岛附近海域为河口湾环境,在风化层以上开始出现淤积,但在4 200 a BP前后受极冷气候的影响,沉积物粗化;自2 500 a BP以来,沉积环境相对稳定,在小冰期期间略有变化。沉积速率计算结果显示:淇澳岛附近海域自中全新世高海面以来的平均沉积速率为0.29 cm/a,4 160~2 500 a BP、2 500 a BP-1488年、1488-1893年、1893-1986年、1990-2007年期间的平均沉积速率分别为:0.17 cm/a、0.23 cm/a、0.35 cm/a、1.37 cm/a和5.94 cm/a,沉积速率逐渐增大,反映了珠江三角洲演化过程中沉积相与沉积环境的变化;1986-1990年期间的海堤建造极大地扰动了该钻孔上部的沉积过程,在工程施工期间共沉积了厚度约112 cm的沉积层,而在海堤建成后,沉积速率也显著增大。沉积物总有机碳、总氮和C/N值的垂向分布表明,在4 160~2 500 a BP期间受海洋环境影响较大,沉积物中有机碳以海源为主,2 500 a BP以来沉积物中碳、氮含量明显增大,C/N也相应变大,有机碳主要来源于陆源输入,但在小冰期期间海源有机碳贡献略有所增大;近百年来由于受人类活动影响显著,陆源有机碳的贡献快速增加。     

Sedimentological parameters and erosion behaviour of submarine coastal sediments in the south-western Baltic Sea

The aim of this study was to evaluate the erodibility of submarine coastal sediments for the purpose of modelling sediment dynamics in Mecklenburg Bay, south-western Baltic Sea. Erosion thresholds derived from experiments with a device microcosm on cores of fine sand (n=5, mean grain size=132 µm) and mud (n=5, medium silt size, mean=21 µm), collected at different times of the year, were compared to theoretical critical shear stress velocities based on grain-size measurements. For this purpose, a sedimentological map of natural surface sediments was constructed for the study area. Calculated values for critical shear stress velocities (u* _{cr-Hjulström} ) are 1.2 cm s^?1 for fine sand, and 3.75 cm s^?1 for cohesive mud. At the mud station, erosion experiments showed an initial transport of the fluffy surface layer (u* _cr-initial ) at a mean critical shear stress velocity of 0.39 cm s^?1. Initial rolling transport at the fine sand station for single sand grains was recorded at values of 0.5 cm s^?1. At higher shear stress velocities, the two sediment types showed diverging erosion behaviour. Measurable erosion (ε>5.0×10^?6 kg m^?2 s^?1) of fine sand starts at a mean critical shear stress velocity (u* _cr-erosion ) of 1.15 cm s^?1 whereas fluffy surface material on mud cores was eroded at mean u* _cr-erosion of 0.62 cm s^?1. This indicates that measured erosion thresholds at the fine sand site fit well to calculated critical shear stress velocities whereas calculated erosion thresholds for cohesive mud are roughly 6 times higher than measured values. As erosion behaviour at the mud station was dominated by fluffy surface material, the comparability of measured and calculated threshold values may be reduced. The underlying silt-sized sediment itself was stable due to cohesive effects. This behaviour has to be taken into consideration by using sediment types instead of mean grain sizes for mapping and modelling sediment dynamics. A comparison of the near-bottom hydrodynamic conditions in the study area and experimentally derived critical shear stress velocities suggests that particle transport is controlled by storm events whereas under calm conditions shear stress velocities do not exceed the critical values.     

漠阳江入海口东侧海岸侵蚀现状及成因分析

对漠阳江入海口东侧海岸的侵蚀情况进行了详细的野外调查,在2年的调查时间内对监测岸段的海岸线位置及海滩地形开展了5次重复测量。各次测量结果的对比表明,漠阳江入海口东侧海岸遭受了严重的侵蚀,岸线平均后退速率达15m.a 1;海滩地形剖面的动态变化则显示海岸侵蚀和淤积情况随季节而改变,在2008年台风"黑格比"登陆后,研究区岸线大幅后退,岸滩地形发生了深刻变化。通过对研究区海岸侵蚀特点的分析,认为砂质海岸的脆弱性和水动力作用是该区海岸侵蚀的基本条件,风暴潮是造成该区海岸严重侵蚀的重要因素;另外,人类活动也加剧了研究区的海岸侵蚀。     

Isotopic and elemental indicators of nutrient sources and status of coastal habitats in the Caribbean Sea,Yucatan Peninsula,Mexico

Nutrient inputs associated with coastal population growth threaten the integrity of coastal ecosystems around the globe. In order to assess the threat posed by rapid growth in tourism, we analyzed the nutrient concentrations as well as the δ¹⁵N of NO₃⁻ and macrophytes to detect wastewater nitrogen (N) at 6 locations along a groundwater-dominated coastal seagrass bed on the Caribbean coast of Mexico. We predicted that locations with greater coastal development would have higher concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (P), as well as δ¹⁵N of NO₃⁻, reflecting wastewater sources of N. However, concentrations of NO₃⁻ were not significantly different between developed (3.3 ± 5.3 μM NO₃⁻) and undeveloped (1.1 ± 0.7 μM) marine embayments. The most important control on DIN concentration appeared to be mixing of fresh and salt water, with DIN concentrations negatively correlated with salinity. The δ¹⁵N of NO₃⁻ was elevated at an inland pond (7.0 ± 0.42‰) and a hydrologically-connected tide pool (7.6 ± 0.57‰) approximately 1 km downstream of the pond. The elevated δ¹⁵N of NO₃⁻ at the pond was paralleled by high δ¹⁵N values of Cladophora sp., a ubiquitous green alga (10 ± 1‰). We hypothesize that inputs of nitrogen rich (NO₃⁻ > 30 μM) groundwater, characterized by ¹⁵N enriched signatures, flow through localized submarine groundwater discharges (SGD) and contribute to the elevated δ¹⁵N signatures observed in many benthic macrophytes. However, changes in nitrogen concentrations and isotope values over the salinity gradient suggest that other processes (e.g. denitrification) could also be contributing to the ¹⁵N enrichments observed in primary producers. More measurements are needed to determine the relative importance of nitrogen transformation processes as a source of ¹⁵N to groundwaters; however, it is clear that continued inputs of anthropogenic N via SGD have the potential to severely impact ecologically and economically valuable seagrass meadows and coral reefs along the Caribbean coast of Mexico.