共查询到20条相似文献，搜索用时 311 毫秒
1.
滨海盐沼孔隙水动力过程研究综述 总被引：1，自引：0，他引：1
滨海盐沼是重要的陆地-海洋交界带生态系统，目前国际上存在关于滨海盐沼系统的两大重要假设：盐沼系统输出养分和盐沼植物带状分布。潮汐影响下盐沼孔隙水动力过程决定着盐沼与近海的物质交换和土壤通风条件，因此为验证两大重要假设，增强科学保护和修复滨海盐沼的能力，滨海盐沼孔隙水动力过程研究至关重要。联系两大重要假设论述了滨海盐沼孔隙水动力过程研究的意义；总结了滨海盐沼孔隙水动力过程野外观测和数值模拟两个方面的研究进展，尤其对模拟潮汐诱导下滨海盐沼孔隙水动力过程的4种数学模型，一维Boussinesq模型、二维饱和模型、二维饱和-非饱和模型、水-气两相流模型进行了系统的探讨；最后，通过对目前研究现状的分析，提出了有关进一步研究的建议。 相似文献
2.
盐沼的侵蚀,堆积和沉积动力 总被引：2，自引：0，他引：2
最近国外对盐沼侵蚀，堆积过程进行了较深入细致的研究，取得了很大进展，主要包括野外短尺度详细的沉积过程观测，室内物理模拟的深度和数学模拟的不断应，本文对此作了综述。这将加深人们对盐沼如何响应海平面、潮型、泥沙供给和波浪气候变化的认识。 相似文献
3.
盐沼前缘陡坎是潮滩环境中盐沼与粉砂—淤泥质光滩交界处的独特地貌形态,研究其形成过程与机理有助于理解盐沼湿地对潮滩发育及其稳定性的影响。根据江苏中部海岸盐城自然保护区核心岸段互花米草盐沼前缘陡坎形态参数（凹槽长度、凹槽宽度和陡坎高度）的分析,发现不同的形态参数组合对应于不同的陡坎演化阶段。根据陡坎形态特征差异,可将盐沼前缘陡坎韵律性形态发育过程分为三个阶段,而这三阶段的交替旋回过程与近岸波向的季节性变化有关。陡坎处的地貌特征与前缘光滩的沉积物特征表明陡坎形态特征形成与波浪作用有关,且显著的陡坎韵律性形态能够部分地应用边缘波理论来解释。 相似文献
4.
于2018年7月6~8日,在黄河三角洲芦苇(Phragmites anstralis)盐沼、盐地碱蓬(Suaeda salsa)盐沼、柽柳(Tamarix chinensis)盐沼和互花米草(Spartina alterniflora)盐沼中,分别采集了0~20 cm深度土柱,按2 cm一层,将采集的土柱分层,测定了不同深度土层的有机碳和可溶性有机碳含量;利用傅里叶变换红外光谱仪,分析了土样中可溶性有机碳的官能团结构特征。研究结果表明,芦苇盐沼、盐地碱蓬盐沼、柽柳盐沼和互花米草盐沼表层土壤中的有机碳和可溶性有机碳含量都在0~2 cm深度层最大,随着土壤深度的增加,二者都在逐渐减小,其陆源有机碳的贡献率分别为79.81%、42.73%、63.45%和34.91%,海源有机碳的贡献率分别为20.19%、57.27%、36.55%和65.09%;生长着4种植物群落的盐沼表层土壤中的可溶性有机碳的红外光谱特征类似,其官能团结构以醇酚类和芳烃类为主,还包括脂肪族、烯烃、卤代烃和仲酰胺类;在波数为1580~1660 cm-1与2800~3010cm-1处,芦苇盐沼、互花米草盐沼、柽柳盐沼和盐地碱蓬盐沼表层土壤中可溶性有机碳红外光谱的峰面积比分别为0.13、0.61、2.27和5.14,盐地碱蓬盐沼表层土壤可溶性有机碳中惰性碳含量最大。 相似文献
5.
《湿地科学》2019,(6)
于2018年7月6～8日,在黄河三角洲芦苇(Phragmites anstralis)盐沼、盐地碱蓬(Suaeda salsa)盐沼、柽柳(Tamarix chinensis)盐沼和互花米草(Spartina alterniflora)盐沼中,分别采集了0～20 cm深度土柱,按2 cm一层,将采集的土柱分层,测定了不同深度土层的有机碳和可溶性有机碳含量;利用傅里叶变换红外光谱仪,分析了土样中可溶性有机碳的官能团结构特征。研究结果表明,芦苇盐沼、盐地碱蓬盐沼、柽柳盐沼和互花米草盐沼表层土壤中的有机碳和可溶性有机碳含量都在0～2 cm深度层最大,随着土壤深度的增加,二者都在逐渐减小,其陆源有机碳的贡献率分别为79.81%、42.73%、63.45%和34.91%,海源有机碳的贡献率分别为20.19%、57.27%、36.55%和65.09%;生长着4种植物群落的盐沼表层土壤中的可溶性有机碳的红外光谱特征类似,其官能团结构以醇酚类和芳烃类为主,还包括脂肪族、烯烃、卤代烃和仲酰胺类;在波数为1 580～1 660 cm~(-1)与2 800～3 010cm~(-1)处,芦苇盐沼、互花米草盐沼、柽柳盐沼和盐地碱蓬盐沼表层土壤中可溶性有机碳红外光谱的峰面积比分别为0.13、0.61、2.27和5.14,盐地碱蓬盐沼表层土壤可溶性有机碳中惰性碳含量最大。 相似文献
6.
黄河三角洲天然和恢复盐沼土壤磷分布特征 总被引：1，自引：0，他引：1
《湿地科学》2015,(6)
在黄河三角洲国家级自然保护区内,以天然和实施"引淡压咸"生态恢复工程的盐沼土壤为研究对象,研究芦苇盐沼、盐地碱蓬盐沼和裸盐沼0~50 cm深度土壤磷含量分布特征及其与土壤理化因子的关系。结果表明,表层土壤(0~20 cm深度)全磷质量比为416.44~714.33 mg/kg,略高于全国平均水平(500 mg/kg);在各形态磷中,无机磷含量最高,残余态磷含量次之,有机磷含量最低;芦苇盐沼和盐地碱蓬盐沼土壤各形态磷含量普遍高于裸盐沼,且芦苇盐沼土壤磷含量最高;恢复盐沼与天然盐沼土壤的全磷、无机磷和残余态磷含量无显著差异,但恢复盐沼土壤有机磷含量低于天然盐沼;天然盐沼土壤磷含量的主要影响因素是土壤有机质含量、电导率、微团聚体比例和粉—粘团聚体比例;恢复盐沼土壤磷含量的主要影响因素为土壤p H和细大团聚体比例。 相似文献
7.
黄河三角洲盐地碱蓬盐沼的时空分布动态 总被引：1，自引：0，他引：1
《湿地科学》2015,(6)
为了研究高强度人类活动背景下的黄河三角洲盐地碱蓬(Suaeda salsa)盐沼斑块空间配置在时间序列上的变化特征,以1984年、1994年、2004年和2014年的遥感影像数据为数据源,研究盐地碱蓬盐沼斑块的面积、周长、形状复杂性指数、空间聚集性和密度的空间配置特征。结果表明,1984~2014年期间,黄河三角洲盐地碱蓬盐沼面积萎缩了约78%,而且盐沼斑块破碎化趋势明显;盐沼斑块的周长面积比和形状复杂性指数随时间显著增大,这将会进一步地导致盐地碱蓬盐沼过度开放,加快盐沼质量的恶化进程;盐沼斑块间的最邻近指数减小,斑块聚集性显著;盐地碱蓬盐沼的斑块密度随时间减小,并向自然潮沟分布密集区域聚集。要有效地开展滨海湿地修复,需要对滨海湿地斑块的历史分布和空间配置有一个更清晰的认识,而不是仅关注湿地面积是否增加,这将对滨海湿地生态修复具有重要的指示作用。 相似文献
8.
向海洋方向入侵的互花米草(Spartina alterniflora)不仅能改变河口生态系统中磷元素的生物地球化学过程,而且能对河口生态系统的稳定和健康产生深刻影响。2019年4月(春季),在闽江河口鳝鱼滩东部的互花米草分布区,采用时空互代法,由陆地向海洋方向,选择互花米草已经入侵5~6 a的盐沼、互花米草已经入侵1~2 a的盐沼和光滩作为研究对象,在互花米草向海洋方向入侵条件下,研究植物—土壤系统中磷的赋存特征及其主要影响因素。研究结果表明,在互花米草向海洋方向入侵条件下,闽江河口鳝鱼滩东部的盐沼土壤中的全磷含量增大;与光滩相比,互花米草入侵5~6 a和1~2 a的盐沼土壤中的全磷含量分别增加了51.6%和27.1%;互花米草向海洋方向入侵不仅改变了盐沼土壤的颗粒组成、电导率、土壤有机质含量和全磷含量,而且改变了互花米草各器官中的全磷含量、磷累积系数和器官之间的磷转运能力;在互花米草已经入侵5~6 a的盐沼中,互花米草主要是通过减小根冠比和提高对磷的吸收和利用,维持其自身的生长;在互花米草已经入侵1~2 a的盐沼中,互花米草则是通过增大根冠比和提高根系向地上器官转运磷的能力,维持其自身的生长。互花米草向海洋方向入侵整体增大了植物—土壤系统的磷储量,提高了土壤有效磷养分的供给能力,这些都有利于加快互花米草向海洋方向入侵的速度。 相似文献
9.
于2018年4月,在辽河口天然芦苇(Phragmites australis)盐沼、油田区芦苇盐沼、退化芦苇盐沼、盐地碱蓬(Suaeda salsa)盐沼、滩涂和稻田中,设置采样点,采集0~10 cm、10~20 cm、20~30 cm和30~40 cm深度的土壤样品,测定土壤样品中的铁和锰元素含量,研究辽河口湿地土壤中铁和锰元素含量的分布特征。研究结果表明,辽河口天然芦苇盐沼、油田区芦苇盐沼、退化芦苇盐沼、盐地碱蓬盐沼、滩涂和稻田的24个采样点0~40 cm深度土壤中的铁元素和锰元素质量比的平均值分别为31.82 g/kg和624.5 mg/kg;油田区芦苇盐沼、天然芦苇盐沼和稻田0~40 cm深度土壤中的铁元素和锰元素含量较大,退化芦苇盐沼、盐地碱蓬盐沼和滩涂0~40 cm深度土壤中的铁元素和锰元素含量较小;辽河口湿地0~10 cm深度土壤中的铁元素含量主要受全磷含量的影响;10~20 cm深度土壤中的铁元素含量主要受总有机碳含量和电导率的影响;20~30 cm深度土壤中的铁元素含量主要受总有机碳含量、全氮含量、全磷含量和电导率的影响;30~40 cm深度土壤中的锰元素含量主要受全磷含量的影响。 相似文献
10.
挥发性氯代烷烃是大气中重要的短命氯源气体,对全球气候变暖和臭氧层破坏具有重要贡献,在全球C和Cl元素循环中扮演着重要的角色,具有非常重要的环境意义。分别于生长季(2004年7月)和非生长季(2005年1月)在苏北海岸带盐沼沿环境梯度采用静态箱技术原位测定氯代甲烷(CH3Cl、CH2Cl2、CHCl3和CCl4)和氯代乙烷(CH3CHCl2和CH3CCl3)6种单体成分通量。结果表明:海岸带盐沼生态系统氯代烷烃单体成分通量关系的差异性主要表现在3个方面:一是海岸带盐沼高氯烷烃不同单体成分间具有很好的相关性,而低氯烷烃CH3Cl与各种高氯烷烃单体成分间相关性不显著。这表明海岸带盐沼低氯烷烃和高氯烷烃的源汇过程可能是不同的,而高氯烷烃间可能存在比较一致的源汇过程;二是高等植物对氯代烷烃不同单体成分贡献的差异性表现为对低氯烷烃CH3Cl表现为源效应,而对高氯烷烃则表现为汇效应;三是盐沼土壤对氯代烷烃不同单体成分的贡献均表现为汇效应,但是研究区低氯烷烃和高氯烷烃来源和生物降解模式不同。低氯烷烃CH3Cl可能源于盐沼植物及其枯落物排放和海洋排放的输入,而高氯烷烃含量既可能来自非生长季盐沼植物和凋落物腐解释放,也可能来自其他区域人类活动排放和海洋排放的外源输入。因此,海岸带盐沼对外源输入的高氯烷烃具有吸纳作用。 相似文献
11.
Robin Rotman Larissa Naylor Rachael McDonnell Conall MacNiocaill 《Geomorphology》2008,100(3-4):241-255
This paper presents the first attempt to use environmental magnetism to quantify sediment provenance on a managed realignment (MR) site. MR is one technique for creating/restoring intertidal habitats and improving the standard of coastal flood protection. Monitoring of MR sites is essential for determining how successful they are at achieving these aims, and normally includes measurement of sedimentation rates through the use of accretion plates and sediment erosion tables (SETs). One limitation of this technique is that the provenance of sediment accreting on realigned surfaces cannot readily be quantified. Our results demonstrate that magnetics-based fingerprinting can successfully apportion sediment source contributions to created/restored coastal saltmarshes with an efficiency similar to that of existing un-mixing models applied to other habitats (82.87%). Analysis of mineral magnetic properties (χFD, IRMsoft and SIRM) demonstrated that the majority of sediment accreting on the Freiston Shore MR Site (Lincolnshire, UK) is derived from established saltmarshes seaward of the breached embankment. This indicates that the MR site may be growing at the expense of neighbouring saltmarshes—thereby undermining the habitat-creation objectives used to justify MR. It is recommended that future MR monitoring programmes consider the provenance of post-breach deposits to help identify any adverse impacts that wetland creation/restoration may have on existing habitats. Further testing of environmental magnetism in coastal saltmarshes and MR sites is necessary to validate wider use of the technique. 相似文献
12.
Patterns, rates and possible causes of saltmarsh erosion in the Greater Thames area (UK) 总被引：2，自引：0，他引：2
The estuary-dominated coast of the Greater Thames in England has experienced rapid lateral erosion and internal dissection of saltmarshes. This paper provides an overview of saltmarsh development in this area, and re-examines the role of environmental and human forcing factors. It draws on documentary evidence, including historical maps, survey data and time-series data of forcing factors. Lateral marsh retreat began in the 19th century in the Medway and Blackwater Estuaries, followed by other estuaries in the Greater Thames region at the beginning of the 20th century. The outer estuaries and the wider parts of the inner estuaries especially have experienced erosion. Erosion has been modest in wave-sheltered areas, e.g., the Colne and the inner Crouch. In the 1960s and, more widely, the 1970s, a phase of rapid erosion took place, with erosion rates of up to ca. 16 ha year−1 per site, notably along the open coast of Dengie and Foulness, and in the Blackwater and Thames Estuaries. At all sites, vertical sediment accretion was well able to keep up with sea level rise over the past century. Evidence indicates that there may have been several causes for the erosion of saltmarshes. These are notably land claim and embankment construction (increasing the tidal range and current velocities) and a continuous rise of, especially, high and extreme water levels. The latest episode of rapid erosion in the 1970s is largely attributed to changes in the wind/wave climate. For example, erosion at wave-exposed sites coincided with a peak in high magnitude waves combined with a high incidence of southeasterly waves. The study shows that many factors, including natural forcing factors and human activities, have to be taken into account when explaining saltmarsh development. 相似文献
13.
发展中长时间尺度的海岸演化预测方法与机理模型,是目前国际海岸演化研究领域关注的焦点和最具挑战性课题。本文系统性地回顾了近半个世纪以来不同时间尺度海岸演化模式的研究发展历程和成果,从动力机制和时间尺度两个方面对海岸演化机理模型存在的主要建模瓶颈问题进行了系统总结。通过对渤海湾西岸近一个半世纪以来海岸演化机制的初步分析,提出了以泥沙收支、环流输送、波浪掀沙以及波气候变化等要素作为年代际尺度海岸演化主要驱动因子,基于驱动力概化与统计升尺度有机衔接的年代际尺度海岸演化机理模型的动力—统计建模方法框架新思路,为推动海岸演化动力学理论体系和中长时间尺度海岸演化预测方法创新,提供了重要科学依据和借鉴。 相似文献
14.
Sedimentation rates in the Wanggang salt marshes, Jiangsu 总被引：1，自引：0，他引：1
WANGAijun GAOShu JIAJianjun PANShaoming 《地理学报(英文版)》2005,15(2):199-209
1 IntroductionLand-ocean interaction in coastalzone is one of the key m atters of the International G eosphereand Biosphere Program (IG BP). The key problem s of the second phase in the next decadeinclude the m aterial cycle, the system evolution process … 相似文献
15.
Coastal salt-marshes represent an important coastal wetland system. The total area of coastal wetlands exceeds 5000 km2 in Jiangsu Province, China, but it is decreasing rapidly in response to the intense reclamation activities and coastal erosion along a part of the coastline. Hence, two types of plants, Spartina angelica and Spartina alterniflora, were introduced successively into the Jiangsu coastal areas, in order to protect the coastline from erosion and to increase the accumulation rate. Pb-210 and Cs-137 analyses were carried out for sediment samples from the salt-marshes of Wanggang to determine the sedimentation rate, on the basis of an evaluation of the background activity values and the factors affecting the enrichment of Pb-210. Analysis of a typical sediment column of the tidal flat shows that there is weak absorption of Pb-210 in the silt-dominated sediment. Because of the influences of factors such as storm events, bioturbation, material sources and analytical error, some abnormal data points appear in the Pb-210 record. After ignoring these data the calculated sedimentation rate was 3.3 cm yr-1 on average. Based upon analysis of the Cs-137 dating, the rate since 1963 was 3.1 cm yr-1 on average, similar to the data by Pb-210 dating and the previous studies. The dating results show that there were three stages of sedimentation, with the most rapid accretion being taking place after Spartina angelica was introduced into the area. The study also shows that at the stage of Spartina alterniflora growth, the accretion rate was higher than on the flat surface with the same elevation without the cover of this plant. 相似文献
16.
Coastal salt-marshes represent an important coastal wetland system. The total area of coastal wetlands exceeds 5000 km2 in Jiangsu Province, China, but it is decreasing rapidly in response to the intense reclamation activities and coastal erosion along a part of the coastline. Hence, two types of plants, Spartina angelica and Spartina alterniflora, were introduced successively into the Jiangsu coastal areas, in order to protect the coastline from erosion and to increase the accumulation rate. Pb-210 and Cs-137 analyses were carried out for sediment samples from the salt-marshes of Wanggang to determine the sedimentation rate, on the basis of an evaluation of the background activity values and the factors affecting the enrichment of Pb-210. Analysis of a typical sediment column of the tidal flat shows that there is weak absorption of Pb-210 in the silt-dominated sediment. Because of the influences of factors such as storm events, bioturbation, material sources and analytical error, some abnormal data points appear in the Pb-210 record. After ignoring these data the calculated sedimentation rate was 3.3 cm yr-1 on average. Based upon analysis of the Cs-137 dating, the rate since 1963 was 3.1 cm yr-1 on average, similar to the data by Pb-210 dating and the previous studies. The dating results show that there were three stages of sedimentation, with the most rapid accretion being taking place after Spartina angelica was introduced into the area. The study also shows that at the stage of Spartina alterniflora growth, the accretion rate was higher than on the flat surface with the same elevation without the cover of this plant. 相似文献
17.
黄河内蒙古河段非汛期和汛期冲淤量计算方法 总被引：1，自引：0，他引：1
基于多沙河流“多来多排”的经验输沙公式,建立了考虑上站来沙量、前期河床累计淤积量、临界输沙水量及干支流泥沙粒径影响的非汛期和汛期输沙量一般表达式。在此基础上,根据黄河内蒙古河段1952-2010年实测的水沙资料,将其应用于黄河内蒙古河段巴彦高勒—三湖河口河段、三湖河口—头道拐河段以及巴彦高勒—头道拐全河段非汛期和汛期输沙量的计算,并应用输沙率法计算了各河段1952-2010年的非汛期和汛期冲淤量及其相应的累计冲淤量。通过输沙量、冲淤量和累计冲淤量计算值与实测值的对比表明,各河段非汛期和汛期输沙量、冲淤量及相应的累计淤积量计算值与实测值的吻合较好,其中非汛期和汛期输沙量计算值和实测值之间的相关系数R2分别约为0.93和0.97;非汛期和汛期冲淤量计算值与实测值之间的相关系数R2分别约为0.80和0.90;非汛期和汛期累计冲淤量之间的相关系数R2分别约为0.94和0.99。结果表明,就吻合程度而言,累计冲淤量优于年冲淤量,汛期优于非汛期。本文建立的冲淤量方法能够很好模拟该河段长历时的非汛期和汛期冲淤过程,可为黄河内蒙古河段输沙量及长期淤积发展趋势的分析提供科学依据。 相似文献
18.
Techniques for simultaneous quantification of wind and water erosion in semi-arid regions 总被引：3，自引：0，他引：3
Wind and water erosion are usually studied as two separate processes. However, in semi-arid zones both processes contribute significantly to soil degradation. Whereas for water erosion the direction of sediment transport is controlled by topography, in wind erosion the direction of transport is controlled by the wind direction. Furthermore, the spatial pattern of erosion and deposition for wind erosion is determined by the spatial distribution of source material, soil erodibility factors and non-erodible roughness elements. Given this difference in dependence on topography, different approaches are needed to determine the mass balance for a given area. For water erosion, the research area has to be defined such that no input of sediment occurs, whereas in wind erosion the input and output fluxes of sediment should be measured, or a non-eroding boundary should be created.In semi-arid regions, wind erosion events are often followed immediately by heavy rain. As wind and water erosion occur almost simultaneously at the same site, the effect of wind and water erosion at a given site should be studied concurrently. To do so, a number of measurement techniques with different spatial and temporal scales are necessary. The research should be started at the scale of a Sahelian field. For a complete insight into the processes at a site, the research should include measurement techniques that quantify the impact of wind and water erosion separately and techniques that quantify their combined effect. 相似文献
19.
江苏王港盐沼的现代沉积速率 总被引：35，自引：0，他引：35
江苏海岸湿地总面积超过5000km^2，但围垦活动的加剧使盐沼湿地面积迅速减少；为了达到海岸防护、保滩促淤的目的，先后引种了大米草和互花米草。通过采集江苏王港潮滩盐沼湿地9处柱状样和挖取探槽剖面，以及对沉积剖面样品进行^210Pb和^137Cs测年分析，探讨了^210Pb的本底及影响^210Pb富集的因素，估算了王港盐沼湿地的现代沉积速率。王港潮滩盐沼沉积物对^210Pb的吸附作用较弱；受风暴潮、生物扰动、物源变化及实验误差等因素的影响，在^210Pbex剖面上出现了数据异常点，将这些数据点剔除后计算得到的沉积速率为33cm yr^-1，^137Cs测年显示，该地区1963年以来的平均沉积速率3．1cm yr^-1，与^210Pb法及前人研究结果相一致。根据一个典型剖面的^137Cs测年数据分析，王港潮滩盐沼的沉积过程根据地貌特征的不同可分3个阶段，大米草覆盖阶段滩面高程迅速增加，互花米草的生长提高了滩面淤积速率。 相似文献
20.
本文从河口塑造与输沙关系、流域泄沙与输移模式,以及口外来沙与潮流输移特征等三方面,探讨河口区的泥沙运移规律和补给来源。并在此基础上,提出粗细不同粒级的造床泥沙按不同方式治理的设想。 相似文献