影响海岸带盐沼土壤有机质、TN和TP含量时空变化的关键因子：潮水和植被

为了更好地理解在潮水和植被交互作用梯度上有机质、全氮和全磷分布的特殊性,分别于生长季和非生长季在苏北盐沼沿近潮沟带和远潮沟带2条样线布设9个固定采样区,采集土壤样品,测定土壤有机质、全氮和全磷的含量。结果表明：植被和潮水的交互作用是决定土壤有机质、全氮和全磷时空变化的关键因素。相对于潮水,植被的影响更为稳定和持久;盐沼土壤有机质和全氮含量具有显著的空间和月份变化,空间变化主要包括植被带（潮水）梯度上和样带间（潮流）的差异,在植被带（潮水）梯度上植被带高于光滩,而植被带间呈现由海向陆的递减趋势,即互花米草(Spartina alterniflora)>盐地碱蓬(Suaeda salsa)>獐茅(Aeluropus littoralis)>芦苇( Phragmites australis);有机质样带间差异表现为在低位盐沼远潮沟带大于近潮沟带,而中位盐沼却是近潮沟带大于远潮沟带,全磷含量时间和空间变化上均不具显著性;pH、土壤含水量和盐分含量等与潮水作用直接相关的因子与距海距离呈负相关关系,土壤有机质、全氮和全磷与距海距离也表现为负相关关系,而土壤有机质、全氮和全磷含量与pH、土壤含水量及盐分含量等因子为正相关关系,一定程度上诠释了潮水对土壤有机质、全氮和全磷含量变化的影响。     

Recent geomorphic changes in the Liaohe Estuary

This paper mainly analyzes the geomorphological changes of the tidal deposition in the Liaohe Estuary based on the multi-year bathymetric charts in 1990, 1996, 2002 and 2005 and Landsat TM images in 1987, 1994, 2002 and 2005. Evolution of the tidal depositional system during the past 20 years in the Liaohe River was studied on the basis of 50 boreholes drilling and 30 km shallow stratigraphic exploration from 2002 to 2005. The main tidal depositional body of the modern Liaohe River delta is located in the Shuangtaizihe Estuary. The stratum within the depth of 10 m includes tidal bank facies, tidal channel facies and neritic facies with paleo-delta facies underlying them. The sediments of tidal bank facies are mainly composed of sand and silt with siltation load and suspended load of about 50% respectively in proportion. The sediment of tidal channel facies and neritic facies is composed of clayey silt and silty clay which belongs to suspended load. The study area was a small bay between the old Daliaohe River, the old Dalinghe River and the Raoyanghe River complex delta since the Holocene to 1896. Many tidal banks formed and expanded rapidly after the Shuangtaizihe River was excavated by labor in 1896. The runoff and sediment discharge have decreased since the construction of brake at the Shuangtaizihe River in 1958.The Shuangtaizihe Estuary is in the state of deposition as a whole whose tidal bank is increasing and expanding southward, westward and northward. The maximum expansion speed is 87 to 683 m/a and the mean depositional rate is 0.189 m/a. Erosion occurred in some part of tidal bank with average erosional rate of 0.122 m/a. The tidal channel was filled up with sediment at a migration speed of 48–200 m/a. Geomorphologic changes have happened under the combined influences of runoff, ocean dynamics and human activities. The main source of sediment changes from river sediment to sediment driven by tidal current and longshore current.     

江苏中部海岸潮沟的形态变化特征

作为一种典型的潮滩地貌单元,潮沟(tidal creeks) 在江苏中部海岸潮间带广泛发育,并表现出复杂的摆动性。本文根据1981-2010 年遥感影像和野外观测数据,对该区潮沟的平面形态变化进行了分析。结果显示,江苏中部海岸潮沟(根据其长度差异) 一般分为4 级,1~3 级潮沟的个数分别为21、97 和688 (1:5:33),其平均长度分别为7587±1544 m、1921±916 m和327±200 m;潮沟在中潮带比较发育,其密度和分汊率明显大于高潮带和低潮带;主潮沟曲率从高潮带向低潮带呈减小趋势;外来引种互花米草扩展和大规模滩涂围垦活动对潮沟产生了较大影响,其中后者明显地抑制了潮沟的发育。研究区潮沟的摆动性具有明显的区域和级别差异。与研究区北部的潮滩区域相比,海岸潮差较大的南部潮滩区潮沟的摆动性较大;同一个潮沟系统其1 级潮沟的摆动性>2 级潮沟>3 级潮沟;同一条潮沟其下段的摆动性>中段>上段;同一区段弯曲岸段的摆动性>顺直岸段;1 级潮沟上段、2 级潮沟中上段、3 级潮沟或位于盐沼内的潮沟其摆动性不明显。     

潮滩围垦对海岸环境的影响研究进展

潮滩围垦是沿海国家拓展陆域, 缓解人地矛盾的最主要方式之一。潮滩围垦通过对潮滩高 程、水沙动力条件、沉积物特征等多种环境因子的改变, 促进生物演替, 并通过垦区土地的人为利 用, 对海岸环境演变产生重要影响。文章从围垦工程对水沙环境的影响、围垦对海岸带物质循环 的影响、围垦对潮滩生物生态学的影响和盐沼恢复与生态重建等4 方面探讨了不同学科学者对 围垦环境影响的主要研究进展及存在的问题, 并指出应加强多学科合作的综合研究, 探讨潮滩围 垦对海岸环境的影响机制, 以寻求兼顾围垦土地需求与海岸带生态保护的持续发展之路。     

盐城滨海湿地退化评估及分区诊断

根据野外监测数据和遥感信息解译结果,分析了盐城滨海湿地生态特征,定量评估了湿地退化程度,分区探讨了导致湿地退化的主导因素。结果表明:①盐城滨海湿地的主要植物为盐地碱蓬(Suaeda salsa)、互花米草(Spartina alterniflora)和芦苇(Phragmitesau stralis)。受湿地基底稳定性和土壤盐度影响,湿地植被呈现出明显的东西分带、南北分区的特点,地带性分布规律明显。②盐城滨海湿地景观类型可以划分为河口水域、盐地碱蓬滩、芦苇沼泽、互花米草沼泽、耕地、建筑用地、养殖池、盐田和光滩9种类型。由于自然因素和人为活动影响,自1980年以后,研究区景观格局发生了巨大变化。自然景观面积减少了33%,人工景观增加了180%。自然湿地中,面积减少最大的是盐地碱蓬滩和芦苇沼泽。③1980～2008年,盐城滨海湿地的互花米草滩面积呈现出增长趋势,盐地碱蓬滩处于严重退化状态,芦苇沼泽处于退化状态,导致盐地碱蓬滩和芦苇沼泽退化的主要因素是人类开发活动。④对不同区域的导致湿地退化的主导因素进行了诊断,其中灌河口—射阳河口岸段湿地退化的主导因素为海岸侵蚀。射阳河口—斗龙港口岸段属于淤蚀过渡海岸,因处于盐城珍禽国家级自然保护区的核心区位置,人类干扰强度不大,湿地退化不严重。斗龙港口—弶港岸段湿地退化的主导因素为人类对湿地的围垦和开发利用活动。     

互花米草盐沼潮沟地貌特征

互花米草是我国从国外引进的能在淤泥质潮滩的高潮带下部和中潮带上部生长的禾木科植物,由于其植株高大、群落盖度高、根系发达等生物学特性,其对潮流动力特征有显著的影响。本文通过对江苏省东台市笆斗垦区外互花米草盐沼地的潮沟形态调查,发现互花米草盐沼潮沟具有以下一些特征:潮沟密度大,可达50km/km²以上;潮沟的宽深比小,大多在8以下;沿岸堤发育,且多呈不对称状;一级主潮沟与主潮沟接头处普遍呈逆弧形;盐沼外侧边缘发育有明显的陡坎冲沟。分析认为这些特征主要与互花米草发达的根系和致密的植株等生物学特性有关,发达的根系增加了盐沼滩面的稳定性,而互花米草高大的植株增加了对潮水运动的阻力,提高了滩面落潮水的归槽水位,改变了潮流的泥沙沉积地点和涨、落潮流的流向,从而形成比较特别的互花米草盐沼潮沟特征。     

江苏中部海岸互花米草扩展对滩涂围垦的响应

根据2001-2013年遥感影像和野外观测数据,对江苏中部海岸互花米草(Spartina alterniflora Loisel)在滩涂围垦期间的扩展过程进行定量化分析。结果显示：2001-2013年互花米草扩展对围垦的响应大体分为三个阶段：2001-2007年,海堤外米草面积较大,每年新增米草面积及米草年扩展率均和新增围垦面积变化同步,且相关性显著;2008-2010年,海堤外米草面积较小,但米草年扩展率仍然较高;2011-2013年,随着围垦的持续进行,米草扩展进入稳定期。因此,互花米草扩展对于滩涂围垦的不同速率和阶段具有不同的响应。若围垦时保留足够宽度的堤前米草,则围垦可以提高米草的年扩展率,其机理是互花米草种子产量和前缘淤积环境是影响米草扩展的主要因素,而围垦对这两方面都有影响。在后期滩涂围垦时,应保证堤外米草宽度在0.9~1 km之间,实现土地资源的可持续利用。     

苏北岸外条子泥沙洲潮沟系统的稳定性研究

以苏北岸外条子泥沙洲潮沟系统为例,分析该区域野外实地测量及历年卫片,分析主要潮沟系统近20年来的动态变化。总结了潮沟系统发育演变的特点,主要表现为各个主干潮沟系统摆动幅度、速率均不相同,单独潮沟系统的各沟段亦有不同的摆动幅度、速率;位于沙洲中部西大港西侧近岸潮沟系统摆动具一定周期性,其东侧潮沟摆动较稳定;潮沟摆动有突变和渐变两种形式。沙洲潮沟系统在多因素的综合作用下具备自动调整作用,主要表现为单一潮沟具有平衡倾向性及沙洲潮沟系统整体的综合布局调整。     

中国特有盐沼植物——海三棱藨草的现状及保护利用

海三棱藨草Scirpus mariqueter是中国特有盐沼植物,也是长江口淤涨型潮滩的典型盐沼先锋植物。在自然状况下,盐沼植被依照盐渍藻类—海三棱藨草—芦苇进行演替。近10年来,由于受长江口的高强度围垦、外来入侵种互花米草的大面积引种和长江中上游来沙量的锐减及全球气候变暖引起的海平面上升的迭加效应影响,海三棱藨草的面积呈加速缩减态势,如若不及时采取相应的保护措施,海三棱藨草将面临灭种的威胁,并由此带来长江河口滩涂湿地生态系统结构和功能的改变。为此,需对长江口滩涂围垦、互花米草种植促淤的人为措施进行深入研究,以保护好中国特有的盐沼植物海三棱藨草,维持长江河口湿地生态系统结构和功能的完整性,更好地发挥其湿地生态系统的服务功能。     

Sedimentary response of Pagham Harbour, southern England to barrier breaching in AD 1910

This paper examines the evolution of Pagham Harbour, southern England following storm-induced breaching of a protective barrier in AD 1910. Stratigraphic studies of sediments collected from intertidal areas show the presence of a distinct stratigraphic horizon in the northeast of Pagham Harbour at ca. 0 to +1.0 m ordnance datum (OD). Radiometric data indicate that this horizon is a ‘reclamation surface’ formed after land claim in AD 1846. Following marine flooding in AD 1910, sediment has accreted relatively rapidly (at a broadly constant rate of between 4 and 8 mm a⁻¹), wave and/or tidal energy have decreased and extensive marshes have developed. An asymptotic reduction in sediment accretion rate through time, as predicted in various theoretical models of salt marsh accretion, is not observed. Over the entire Pagham Harbour area, the period between AD 1948 and AD 1986 has seen an average marsh loss of 0.0087 km² a⁻¹, which is relatively small in comparison with other more exposed sites in the local area. Historically breached sites such as Pagham Harbour are common around European coasts, and these provide important natural laboratories within which the medium-term (decadal to centennial) coastal response to barrier breaching, and to managed-realignment coastal protection schemes, can be assessed.     

30-year response to damming of a Mediterranean river in California,USA

Dry Creek is a major tributary of the Russian River in Northern California (USA) that has experienced hydrologic and morphologic alterations after the closure of Warm Springs Dam in 1983. Our objective is to present a detailed diagnosis of the modification of the creek’s flow and sediment regimes, and interpret the alterations regarding the ecomorphologic evolution previously observed in the creek. Statistical analysis of the river’s flow and sediment series indicates that dam operation has had significant impacts on the magnitude and frequency of occurrence of the highest floods, and the magnitude, variability, and duration of low and very low flows. Similarly, sediment concentration and discharge have also experienced major alterations. Loss of habitat complexity for native flora and fauna (especially endangered salmonids), channel incision, and vegetation encroachment are some of the negative trends found for the creek over the last 30 years, since river regulation began. We discuss the present dynamics of the river and propose, on that basis, the improvement of its hydromorphic functioning as part of future large-scale restoration initiatives.     

Evolution of sedimentary environments of the middle Jiangsu coast, South Yellow Sea since late MIS 3

An evolutionary model of sedimentary environments since late Marine Isotope Stage 3 （late MIS 3, i.e., ca. 39 cal ka BP） along the middle Jiangsu coast is presented based upon a reinterpretation of core 07SR01, new correlations between adjacent published cores, and shallow seismic profiles recovered in the Xiyang tidal channel and adjacent northern sea areas. Geomorphology, sedimentology, radiocarbon dating and seismic and sequence stratigraphy are combined to confirm that environmental changes since late MIS 3 in the study area were controlled primarily by sea-level fluctuations, sediment discharge of paleo-rivers into the South Yellow Sea （SYS）, and minor tectonic subsidence, all of which impacted the progression of regional geomorphic and sedimentary environments （Le., coastal barrier island freshwater lacustrine swamp, river floodplain, coastal marsh, tidal sand ridge, and tidal channel）. This resulted in the formation of a fifth-order sequence stratigraphy, comprised of the parasequence of the late stage of the last interstadial （Para-Sq2）, including the highstand and forced regressive wedge system tracts （HST and FRWST）, and the parasequence of the postglacial period （Para-Sql）, including the transgressive and highstand system tracts （TST and HST）. The tidal sand ridges likely began to develop during the postglacial transgression as sea-level rise covered the middle Jiangsu coast at ca. 9.0 cal ka BP. These initially submerged tidal sand ridges were constantly migrating until the southward migration of the Yellow River mouth to the northern Jiangsu coast during AD 1128 to 1855. The paleo-Xiyang tidal channel that was determined by the paleo-tidal current field and significantly different from the modern one, was in existence during the Holocene transgressive maxima and lasted until AD 1128. Following the capture of the Huaihe River in AD 1128 by the Yellow River, the paleo-Xiyang tidal channel was infilled with a large amount of river-derived sediments from AD 1128 to 1855, causing the emergence of some of the previously submerged tidal sand ridges. From AD 1855 to the present, the infilled paleo-Xiyang tidal channel has undergone scouring, resulting in its modern form. The modern Xiyang tidal channel continues to widen and deepen, due both to strong tidal current scouring and anthropogenic activities.     

近期长江北支口门圆陀角附近潮滩地貌动态变化

圆陀角位于长江北支岸线与江苏海岸线的交会处,独特的互花米草潮滩、淤泥质光滩环境和复杂的河海沉积动力,决定了潮滩地貌对海洋环境变化的响应具有敏感性。由于大规模的围垦,圆陀角附近过去40年来海岸线向东推进了6km。根据2006年以来多次的野外调查和室内粒度与钻孔岩芯的¹³⁷Cs分析, 2006年以来圆陀角附近潮滩淤积明显加强,由¹³⁷Cs时标估算的互花米草滩多年平均沉积速率为2.3cm/a, 2006~2008年观测到的互花米草滩淤积速率>4cm/a,粉砂淤泥质光滩的淤积速率更高;圆陀角风景区内互花米草滩前缘陡坎在风暴潮影响下侵蚀后退,并因粉砂淤泥质光滩的快速淤长而消亡,圆陀角附近潮滩地貌动态是对人类围垦活动、风暴潮与潮汐海洋动力的综合响应,互花米草与光滩快速淤积是近期圆陀角附近潮滩地貌演化的主要特点。     

琼州海峡水沙输运特征研究

根据1995年2～3月在琼州海峡两岸12个站点的同步观测资料,本文集中分析研究了海峡的水沙输运特征。琼州海峡潮流作用活跃,流速平均在015～074ms^-1(大潮)和012～051ms^-1(小潮)之间。海峡悬沙浓度大小潮十分接近(分别为0028kgm^-3、0026kgm^-3),并具有明显的时间性和地域性。周日单宽悬沙输运量在30～11000kg之间。潮流和波浪产生的泥沙再悬浮对海峡含沙量有较大影响,潮流作用还造成底质沉积物的运动,海峡周日单宽推移质输运率最大可达16400kg。受潮波系统和地形地貌影响,海峡北岸输水、输沙方向以西向为主,南岸以东北、东南向为主,流速、余流、悬沙输运通量皆具有大潮强于小潮,北岸强于南岸的特点     

A Review of “The Illustrated History of Natural Disasters”

Zonal patterns of salt marsh plants and physical conditions have been addressed primarily across the elevation gradient from inland to coastline rather than across tidal creeks in relation to their hydro-geomorphic processes such as bar formation and bank erosion. We found at a Danish marsh that by shaping major geomorphic features and providing sediments to the adjacent sites, fluvial-geomorphic processes of tidal creeks exert fundamental controls on the cross-channel distribution of abiotic and biotic factors. These results point to a need for biogeomorphic and landscape ecological perspectives to fully understand the underlying structure and geographic variability in salt marshes.     

江苏沿海互花米草盐沼动态变化及影响因素研究

收集1988～2001年12个时相的江苏盐城幅卫星影像，提取双洋河口至梁垛河闸之间的互花米草盐沼，统计不同时期的分布信息。分析表明：互花米草盐沼在江苏扩张非常迅速，到2001年7月互花米草盐沼分布面积达129．28km^2,从射阳河口至梁垛河闸之间的潮间中上带泥滩大部分已被互花米草盐沼所覆盖；由于生态位的影响，互花米草盐沼沿平行于海岸线方向扩张速度快于垂直于海岸线方向的扩张速度；依据野外调查和卫星影像分析，互花米草盐沼扩张可分为立地、快速扩张及成熟3个阶段。此外，还对互花米草盐沼的影响因素进行了探讨。     

黄土丘陵沟壑区岔巴沟下游泥沙传输 时间尺度动态研究

泥沙动态研究目前仍然不够完善, 尤其是在黄土丘陵沟壑区, 有关泥沙传输时间动态的 研究论文还不多见。本文利用岔巴沟下游长达8 年的水沙资料, 探讨了该区不同时间尺度( 洪水 内、月和季节及年际尺度) 上泥沙传输动态。结果表明, 在洪水内时间尺度上, 洪峰超前于沙峰的 事件占洪水事件总数的63.2%, 洪峰和沙峰同时发生及洪峰落后于沙峰的洪水事件则各占 18.4%左右。受高含沙水流的影响, 洪水事件产流量- 含沙量呈现逆时针滞后环, 而与洪峰和沙峰 出现的先后顺序无关。在月和季节尺度上, 存在着可蚀物质“储备- 释放”的过程, 即在晚秋(10 和 11 月份)、冬季和春季可蚀物质是一个积聚过程, 在夏季和早秋( 9 月份) 是泥沙输出流域的释放 过程。在年际尺度上, 含沙量和产沙量年际变化大, 主要与年内发生的洪水事件次数和幅度有关。     

海南博螯沿岸地貌与人类活动的潜在影响

The Boao coastal system along the eastern coast of Hainan Island is a dynamic delta-tidal inlet-barrier formed during the late Holocene. The delta developed inside a shallow lagoon barred by a sandy barrier with a narrow, shallow tidal inlet opening. Two major distributary channels separated by small islands characterize the delta. The lagoon is silting up receiving and trapping sediments from both the river and, in minor measure during storms, through the tidal inlet opening and barrier washovers. The barrier at the tidal inlet is highly dynamic and changes its form, accreting (migrating spit) against the inlet during fair-weather conditions and being eroded during storms and river floods.The delta has almost completely filled the lagoon and major concerns exist on the effect that ongoing large development plans may have on the environment. These concerns include the effect on floods and rate of siltation once banks of the islands have been stabilized and floodwater and sediment load are impeded from spreading over the lowlands, and the effect of increasing pollutant loads from the new facilities on the ecosystems of the increasingly restricting lagoon water and on the seashores.     

Geomorphology of the Boao coastal system and potential effects of human activities -Hainan Island, South China

1 IntroductionThe objectives of this paper are to analyze the principal characteristics of the W anquan Riverdelta that has developed in a narrow , shallow lagoon, and to determ ine the effect that theever-increasing hum an activities of the area m ay hav…