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1.
海岸带潮滩地形具有快速变化的特点;在盐沼植被覆盖的潮滩区域,地面激光扫描仪（terrestrial laser scanning,TLS）获取地形数据受到地表植被的影响。为了研究TLS在盐沼潮滩使用的地形测量精度与盐沼植被种类、盖度的关系,本文以芦苇群落、白茅群落、互花米草群落、海三棱藨草群落4种典型海岸带盐沼植被群落为研究对象,在移动窗口法的基础上辅以聚类分析的植被滤除算法,分别从点云原始数据中恢复地表地形地貌特征。研究结果表明：1）植被盖度越高,TLS反演地形精度越低,两者负相关。2）不同植被的激光穿透能力不同：盖度大于50%时,激光无法穿透原始盖度分别为70%、65%、65%的白茅群落、互花米草群落、海三棱藨草群落,均方根误差（root-mean-square error,RMSE）分别为22.0、22.0、8.6 cm;盖度等于50%时,白茅群落、海三棱藨草群落、芦苇群落和互花米草群落的RMSE分别为16.0、6.6、4.5、5.7 cm;盖度小于50%时,芦苇群落、互花米草群落、海三棱藨草群落地形反演精度小幅度提高,白茅群落地形反演精度提升较为明显。3）在盐沼潮滩地区使用TLS反演地形时,增加TLS架设高度、对同一区域多方位反复扫描可能有助于提高地形反演效果。 相似文献
2.
长江口潮滩植物根际重金属的分布与累积 总被引：11，自引：0，他引：11
长江口滨岸潮滩芦苇与海三棱燕草根系、茎叶以及根际沉积物中Cu、Pb、Mn、Zn、Cr的含量分析发现，Cu、Pb、Zn、Cr在根系中的含量较高，而Mn在茎叶中的含量达到总量的55％以上。海三棱燕草比芦苇能更有效地累积重金属，两种植物根系。沉积物系统均表现出明显的重金属含量季节变化。植物体内重金属含量一般在冬季富集；芦苇根际沉积物中重金属的含量秋季较低，冬季富集，而海三棱蒲草根际沉积物中Cu、Pb、Mn均在秋季含量较高，Zn、Cr冬季含量最高。 相似文献
3.
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
4.
夏季长江河口潮间带反硝化作用和N2O的排放与吸收 总被引：15，自引：1，他引：15
采用培养箱乙炔抑制和现场静态箱法,于夏季(7月)在长江河口潮滩潮间带进行了采样,研究表明,长江河口潮滩水体自身N2O产生速率很低,在潮汐淹没期沉积物是上覆水体N2O的来源,其来自沉积物中反硝化、硝化等氮素循环的多个反应过程,沉积物中N2O自然产生速率在0.10～8.50μmol/(m2·h)之间,反硝化速率在21.91～35.87μmol/(m2·h)之间。退潮出露期中潮滩是大气N2O的排放源犤交换速率在-11.03～13.17μmol/(m2·h)之间犦,5～10cm地温是影响N2O排放速率的显著性因素;低潮滩-大气界面N2O排放、吸收速率在-5.75～0.49μmol/(m2·h)之间。总体上看,中潮滩是大气N2O的排放源;而低潮滩对大气N2O有明显的吸收作用。潮滩植被(海三棱草和底栖藻类)的光合作用明显抑制了N2O的排放并可能导致吸收,而其呼吸作用则增加了N2O的排放,潮间带-大气界面N2O的排放和吸收与CO2的排放、吸收有显著的正相关关系。 相似文献
5.
为研究芦苇盐沼植物在一个生长周期不同生长季节的雷达后向散射系数变化特征,对芦苇分布信息进行提取,探究Sentinel-1A卫星数据在长江口湿地植被监测中的应用前景。以对长江河口崇明东滩南部为研究区域,利用2016年11个时相的Sentinel-1A雷达卫星影像VV（vertical transmit/vertical receive）+VH（vertical transmit/horizontal receive）双极化数据,分析潮滩地带芦苇、白茅、海三棱藨草、水体和光滩在植被生长周期内的雷达后向散射强度变化特征,对芦苇盐沼植被进行识别提取。结果表明：相较于VH极化方式,VV极化方式下不同地物的后向散射强度差异更为明显,芦苇的后向散射强度在枯叶期下显著高于其他地物;进行芦苇植被提取时,需要对植被枯萎期不同潮位状况下的雷达影像进行组合运算,芦苇提取精度可达到88.7%;对芦苇植被雷达后向散射强度和临近时相的光学遥感归一化植被指数（normalized difference vegetation index,INDV）进行相关性分析,发现两者呈良好的正相关关系,相关系数为0.78。 相似文献
6.
天津市潮间带表层沉积物的类型及其分布 总被引：4，自引：2，他引：2
根据在天津市潮间带地区采集的108个底质样品的粒度分析结果,划分了潮间带表层沉积物的类型,并探讨了潮间带的粒度分布特征和沉积作用。结果表明,天津潮间带可分为3个岩性区,分别以海河口、独流减河口为界,海河口以北至涧河口为片状粘土质粉砂分布区,海河口以南至独流减河口为多岩性、条带状的砂-粉砂分布区,独流减河口至歧口为片状粘土质粉砂分布区。海河口以北的潮间带是以低能潮汐作用为主的泥质粉砂潮滩沉积环境,海河口以南的潮间带是以河口沉积为主体,后经潮汐改造的潮滩环境,驴驹河-独流减河河口岸段潮间带早期水动力较强,后受到潮滩环境的改造,歧口岸段潮间带以潮滩沉积环境为主。 相似文献
7.
长江口盐沼硫酸盐还原菌的分布特征与环境机制 总被引：3，自引：0，他引：3
选择长江口崇明东滩两类植被区（互花米草、土著植被）纵向剖面,根据不同高程部位柱样土壤和植被根际硫酸盐还原菌（SRB）与异养菌的数量,颗粒有机碳（POC）含量与δ13C值,孔隙水Cl-/SO2- ４摩尔比等,研究盐沼SRB的空间分布特征与机制。自高潮滩向光滩,柱样氧含量降低,SO2- ４含量增加,导致SRB含量增加,SRB在有机质矿化中的作用增强。高潮滩柱样不同深度层位的异养菌数量明显大于中潮滩和光滩柱样的相应层位,这与由陆向海柱样氧含量及POC含量降低有关。SRB对植被根际环境的变化较敏感,芦苇根际最有利于SRB生长,藨草根际次之;互花米草根际不利于SRB生长,根系分泌物可能对SRB有抑制作用。土壤有机质含量是导致不同纵向剖面相同高程部位柱样之间微生物数量差异的主要因素。同一纵向剖面不同高程部位柱样之间在土壤氧含量与SO2- ４含量方面的不同,导致这些柱样微生物数量存在差异。盐沼柱样孔隙水Cl-/SO2-４摩尔比总体偏低,多小于19.33,指示有非海源SO2- ４加入。非海源SO2-４的加入掩盖了硫酸盐还原作用对SO2-４的消耗,增加了利用孔隙水Cl-/SO2-４摩尔比定量研究盐沼硫酸盐还原作用强度的难度。柱样中SRB越多,Cl-/SO2-４摩尔比就越大,硫酸盐还原作用就越明显。 相似文献
8.
福建罗源湾潮滩沉积过程对人类活动和台风事件的响应 总被引：1，自引：0，他引：1
潮滩地区是人类活动和台风事件影响最为显著的地区之一,利用潮滩沉积记录可以提取影响区域重大人类活动和台风事件的历史变化。罗源湾潮滩中上部盐沼和光滩柱状沉积物粒度分析结果显示,罗源湾潮滩沉积物以细颗粒为主,盐沼内部和潮滩中上部光滩柱状沉积物平均粒径分别为5.41~45.00 μm和5.4~68.82 μm,但在不同深度出现多次沉积物变粗的现象;利用210Pb测试计算得到的沉积速率分别为1.96 cm/a和1.23 cm/a;近年来的围填海活动导致潮间带地区沉积速率显著增大,互花米草的引种也进一步导致潮间带上部沉积速率增大。台风的强烈影响使得潮间带沉积出现间断,在沉积间断界面出现沉积物粒度变粗的现象,由此推断了近170年来显著影响罗源湾地区的台风事件沉积层的位置,并由此计算了不同时段的沉积速率。根据柱状沉积物粒度分析结果,不仅可以反演近百年来的对罗源湾产生重要影响的台风事件,也可以反演20世纪50年代以来罗源湾经历的几次较大规模的人类活动。 相似文献
9.
夏季长江口潮间带CH4、CO2和N2O通量特征 总被引：5，自引：0，他引：5
使用原位静态箱现场采样,对夏季(7月和8月)长江口崇明东滩湿地3种主要温室气体CO2、CH4和N2O的界面通量进行了同步观测.结果表明,夏季低潮滩是大气CH4的排放源(40.2 μg/(m2·h)),CO2和N2O的吸收汇(通量值分别为-86.3 mg/(m2·h),-27.6 μg/(m2·h)).7月和8月中潮滩是3种温室气体的排放源,CH4日平均排放速率达到6.56 mg/(m2·h),CO2为301 mg/(m2·h),N2O为69.9 μg/(m2·h).温度(气温和不同深度地温)、沉积物有机碳含量以及潮滩植被海三棱藨草和沉积物表层藻类的光合和呼吸是决定CH4、CO2、N2O产生、排放和吸收的主要因素.相关分析表明中潮滩气体排放通量与温度(气温和不同深度地温)呈显著正相关关系,但在低潮滩气体通量与温度的相关关系不明显. 相似文献
10.
海岸带盐沼植被可以减缓流速,具有重要的缓流固滩功能。本文以长江口崇明东滩盐沼区植被海三棱藨草（Scirpus Mariqueter）为研究对象,设置“光滩—植被带边缘—植被带”的观测样带,研究生长中期、生长后期和枯萎期不同物候期海三棱藨草缓流能力的差异。结果表明：海三棱藨草植被带具有显著的缓流能力,平均流速小于相邻光滩,缓流能力强于相邻光滩,单位距离流速衰减率是光滩的1.47～3.48倍;不同物候期缓流能力存在差异,呈现生长中期>生长后期>枯萎期的规律,生长中期、生长后期和枯萎期的单位距离流速衰减率分别为1.15%,1.06%和0.50% m-1。海三棱藨草植被带的单位距离流速衰减率与植被带边缘流速呈正相关,3个物候期的相关性系数（R）均大于0.80;除枯萎期为正相关外,生长中期、生长后期植被单位距离流速衰减率与边缘水深为负相关,R的绝对值均超过0.90。 相似文献
11.
《Applied Geochemistry》2005,20(6):1195-1208
The upper intertidal zone, and salt marshes in particular, have been shown by numerous authors to be effective medium to long-term storage areas for a range of contaminants discharged or transported into the estuarine environment. A detailed understanding of the specific controls on the trapping and storage of contaminants, however, is absent for many estuarine systems. This paper examines heavy metal distribution and accumulation in two contrasting Spartina sp.-dominated macrotidal salt marsh systems – a rapidly prograding, relatively young marsh system at the Vasiere Nord, near the mouth of the Seine estuary, France, and a more mature, less extensive marsh system in the Medway estuary, UK. The spatial distribution of the heavy metals Zn, Cu, Pb, Ni and Co is assessed and compared in both systems via detailed surface sampling and analysis, while the longer-term accumulation of these metals and its temporal variability is compared via analysis of dated sediment cores. Of the two sites studied, the more extensive marsh system at the Vasiere Nord in the Seine estuary shows a clear differentiation of heavy metals across the marsh and fronting mudflat, with highest metal concentrations found in surface sediments from the more elevated, interior marsh areas. At Horrid Hill in the Medway estuary, the spatial distribution of heavy metals in surface sediments is more irregular, and there is no clear relationship between heavy metal concentration and site elevation, with average concentrations similar in the marsh and fronting mudflats. Sediment core data indicate that the more recent near-surface sediments at Horrid Hill are clearly more contaminated than those at greater depth, with most heavy metal contamination confined to the upper 20 cm of the sediment column (with peak metal input in the late 1960s/early 1970s). In contrast, due to extremely rapid sediment accretion at the mouth of the Seine, heavy metal distribution with depth at the Vasiere Nord site is relatively erratic, with metal concentrations showing a general increase with depth. These sediments provide little information on temporal trends in heavy metal loading to the Seine estuary. Overall, heavy metal concentrations at both sites are within typical ranges reported for other industrialised estuaries in NW Europe. 相似文献
12.
We report electrochemical profiles from unvegetated surficial sediments of a Georgia salt marsh. In creek bank sediments, the absence of Sigma H2S or FeSaq and the presence of Fe(III)-organic complexes suggest that Mn and Fe reduction dominates over at least the top ca. 5 cm of the sediment column, consistent with other recent results. In unvegetated flats, accumulation of Sigma H2S indicates that SO42- reduction dominates over the same depth. A summer release of dissolved organic species from the dominant tall form Spartina alterniflora, together with elevated temperatures, appears to result in increased SO42- reduction intensity and hence high summer concentrations of Sigma H2S in flat sediments. However, increased bioturbation and/or bioirrigation seem to prevent this from happening in bank sediments. Studies of biogeochemical processes in salt marshes need to take such spatial and temporal variations into account if we are to develop a good understanding of these highly productive ecosystems. Furthermore, multidimensional analyses are necessary to obtain adequate quantitative pictures of such heterogeneous sediments. 相似文献
13.
长江口盐沼土壤有机质分布与矿化的空间差异 总被引：2，自引：0，他引：2
在长江口崇明东滩两类植被(互花米草、土著植被)区域分别选择一条纵向剖面,在高潮滩、中潮滩及光滩取得柱状样,利用颗粒有机碳(POC)含量、碳稳定同位素组成、土壤C/N比与颗粒组成等资料,研究盐沼有机质的分布与矿化特征。结果表明,两个纵向剖面的相同高程部位柱样之间,颗粒有机碳δ13C与POC含量的深度特征均存在显著差异;两个柱样的δ13C与POC含量的平均值均相差较大。互花米草对高潮滩柱样有机质的含量与组成均产生了明显影响,对中潮滩柱样有机质组成已有一定影响;土著植被对高潮滩柱样有机质组成的影响显著。盐沼植被对土壤有机质的分布与矿化均产生了明显影响。高潮滩柱样矿化阶段不同的有机质组分混杂,中潮滩柱样有机质的组成相对简单,矿化程度较弱。柱样粘粒含量与含水量在垂向上变化频繁,盐沼原始沉积层序对柱样的物质分布特征具有本底制约。不同高程部位柱样之间,有机质的深度分布特征以及矿化程度差异显著,盐沼碳动态受到潮滩特征性动力沉积过程的显著影响。 相似文献
14.
L. A. Cifuentes 《Estuaries and Coasts》1991,14(4):414-429
Terrestrially-derived organic matter in sediments of the Delaware Estuary originates from riverine transport of soils and fresh litter, sewage and industrial wastes, and marsh export of organic matter. The quantity, composition, and spatial distribution of terrigenous organic matter in sediments was determined by elemental (C and N), lignin, and stable carbon isotope analyses. Sediments in the upper Delaware Estuary had low organic carbon content and high lignin content. In contrast, sediments in the lower Delaware Estuary had high organic carbon content and low lignin content. There was a slight decrease in the proportion of syringyl and cinnamyl phenols relative to vanillyl phenols between the upper estuary and lower estuary. Differences in lignin and stable carbon isotope compositions between sediments of the Delaware Estuary and sediments of the Broadkill River estuary (an adjoining salt-marsh estuary) supported previous observations that marshes do not export substantial quantities of organic matter to estuaries. Additional results suggested that lignin-rich sediments were concentrated in the upper estuary, most likely in the zone of high turbidity. Furthermore, algal material diluted lignin-rich sediments, particularly in the lower estuary. The weaker algal signal in bottom sediments compared to that in suspended particulate matter suggested algal material was decomposed either in the water column or at the sediment-water interface. Physical sorting of sediments prior to deposition was also indicated by observations of compositional differences between the upper and lower estuary bottom sediments. Finally, seasonal variations in primary productivity strongly influenced the relative abundance of terrestrial organic matter. In fall, however, the proportion of lignin was greatest because of a combination of greater inputs of terrestrially-derived organic matter, lower river discharge, and a decrease in algal biomass. 相似文献
15.
潮间带盐沼植物对海岸沉积动力过程影响的研究进展 总被引：11，自引：1，他引：11
根据已有文献归纳出盐沼植物对水动力、悬沙运动、沉积、地貌影响研究已取得的进展，包括：①单位距离盐沼中波能的损失可为相邻光滩的数倍至数十倍；波浪传入互花米草盐沼20~30 m后，波能可全部损失；②盐沼植物可使潮流流速降低一个数量级；当植冠被淹没后，垂向流速剖面在植冠附近出现转折；③当植冠被淹没后，垂向上植冠层内的紊动强度趋于一致且明显低于植冠层以上；互花米草盐沼中的紊动强度可比相邻光滩低1~2个数量级；④盐沼植物通过2种机制影响悬沙的运动：其一是降低水体紊动，从而促进悬沙的沉降并遏制滩面沉积物再悬浮；其二是茎叶对悬沙的直接黏附。这两种机制可使盐沼中的悬沙浓度比相邻光滩低一半以上；⑤植物对细颗粒悬沙的促淤作用导致盐沼中的底床滩面沉积物细化；⑥盐沼中的垂向沉积速率可比光滩高7~8倍；盐沼中波痕和侵蚀坑等微地貌不易发育，滩面平整化；与光滩上频繁发生的冲淤交替相比，盐沼中通常只淤不冲，滩面稳定性较高；⑦植物对上述沉积动力过程的影响程度与植物的高度、密度、盖度等生态参数密切相关，因此，不同的植物种类对沉积动力过程的影响往往存在显著差异。在此基础上，展望了今后该领域研究进一步加强的几个方面。
[HT5H]关〓键〓词：[HT5K]
[HT5H]中图分类号:〓〓〓文献标识码：A[HT5SS][HK] 相似文献
16.
长江口盐沼滩面发育对有机碳深度分布的制约 总被引：1，自引：0，他引：1
通过对长江口崇明东滩高潮滩、中潮滩以及光滩柱状样的有机碳含量与碳稳定同位素组成（δ13C）、粒度组成等的测定，研究盐沼有机碳深度分布特征与形成机制。结果表明，盐沼土壤颗粒有机碳（POC）主要赋存于粒径小于0.016 mm的颗粒中，POC含量对粒径在0.002~0.004 mm区间的颗粒含量变化最敏感，说明盐沼POC主要来自长江径流悬移质，这与有机碳稳定同位素结果一致。土壤POC含量与不同粒径区间颗粒含量相关关系表明，高潮滩与中潮滩柱样的泥沙级配较为接近；光滩柱样POC含量与不同粒径区间颗粒含量相关关系特征与高、中潮滩柱样的基本类似，主要不同表现在粒径大于0.016 mm的粗颗粒，这很可能受控于盐沼不同高程部位动力沉积过程。盐沼植被对高、中潮滩柱样POC的贡献相当可观，个别层段高达55.6%；植被对土壤POC的贡献受到滩面过程的明显制约。滩面动力沉积过程形成盐沼垂向上独特的沙、泥纹层构造，其优良的封堵效能显著影响土壤有机碳的垂向分布。盐沼滩面动力沉积过程是塑造有机碳深度分布特征的关键因素。 相似文献
17.
A process-based numerical model is applied to investigate sediment transport dynamics and sediment budget in tide-dominated estuaries under different salt marsh erosion scenarios. Using a typical funnel-shaped estuary (Ribble Estuary, UK) as a study site, it is found that the remobilization of sediments within the estuary is increased as a result of the tidal inundation of the eroded salt marsh. The landward export of the finest sediment is also intensified. The relationship between salt marsh erosion and net landward export of sediments has been found to be non-linear—with the first 30% salt marsh erosion causing most of the predicted export. The presence of vegetation also influences the sediment budget. Results suggest that vegetation reduces the amount of sediment being transported upstream. Again, the trapping effect of salt marsh in terms of plant density is non-linear. Whilst a vegetated surface with a stem density of 64 plants/m2 decreased the net landward export of very fine sand by around 50%, a further increase in stem density from 64 to 512 plants/m2 had a relatively small effect. 相似文献
18.
Costa Larissa Mirlean Nicolai Quintana Guilherme Adebayo Segun Johannesson Karen 《Aquatic Geochemistry》2021,27(2):79-103
Arsenic (As), iron (Fe), and manganese (Mn) contents were measured in sediment nodules and associated pore waters obtained from sediment cores collected from a salt marsh on Pólvora Island (southern Brazil). Sediment cores were obtained when brackish water dominated the estuary, at two different environments: an unvegetated mudflat colonized by crabs (Neohelice granulata), and a low intertidal stand vegetated by Spartina alterniflora. We determined the percentage of nodules in each depth interval of the cores, along with redox potential, and As, Fe, and Mn contents of the nodules. The mineralogy of the nodules was investigated, and results showed they are mainly composed by quartz, phyllosilicates, and amorphous Fe–Mn oxides/oxyhydroxides. Pore water results showed that bioturbation by local crabs supports oxygen penetration to depths of ca. 25 cm below the salt marsh surface, with lower Fe contents in pore water associated with the brackish period. However, S. alterniflora growth appears to have a greater impact on sediment geochemistry of Fe, Mn, and possibly As due to sulfate reduction and the associated decrease in pore water pH. Higher Fe concentrations were observed in the pore waters during the period of brackish water dominance, which also corresponded to the S. alterniflora growth season. The study demonstrates that differences in geochemical conditions (e.g., Fe content) that can develop in salt marsh sediments owing to different types of bioirrigation processes (i.e., bioirrigation driven by crabs versus that related to the growth of S. alterniflora) play important roles in the biogeochemical cycling of As.
相似文献19.
长江口吴淞-浏河滨岸带沉积物AVS和SEM含量的空间分布特征 总被引：1，自引：0，他引：1
对长江口吴淞-浏河滨岸带37个站位沉积物中酸可挥发性硫化物（AVS）和同时可提取态重金属（SEM）含量及其空间分布特征进行了研究。结果表明,SEM在37个站位沉积物中浓度范围为0．20～1．37μmol／g,平均值为0．74μmol／g;AVS的浓度范围为0．20—0．80μmol／g,平均值为0．23μmol／g;沉积物中AVS含量与总有机碳（TOC）和含水率呈显著正相关关系,而SEM分别与TOC和含水率呈显著正相关关系,与沉积物中值粒径呈显著负相关关系。依据SEM／AVS比值评价方法以及美国EPA（SEM—AVS）差值评价方法对沉积物中重金属的生物有效性的判断表明,除了B2站点无显著生物毒性外,吴淞-浏河滨岸带沉积物中重金属对水生生物均处于中等毒性水平。 相似文献