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研究河口沙洲及其植被的演变规律对维护河势稳定、保护河口地区生态环境具有重大意义。然而在较大时空尺度上，针对河口沙洲演变与其植被变化之间的相互作用关系尚讨论不足。因此，本文通过对文献资料中九段沙区域河势演变、涉水工程、植被面积等数据的收集和总结，结合海图及遥感影像分析，归纳分析了近三十年九段沙沙体及植被的演变特征及其相关作用关系。结果显示，近三十年九段沙沙体扩张明显，特别是0m以上沙体面积增长迅速，总增长达到176.5%；而5m等深线以内沙体面积扩张相对缓慢。九段沙区域河口汊道分流比、分沙比、悬沙浓度等水文、泥沙要素变化显著。九段沙植被面积由1990年的9.1 km2扩张到了2015年的65.68 km2，其中不同植被类群的变化特征有所不同。筛选得到的与0m等深线以内沙体面积变化具有显著相关性的环境因子包括互花米草群落面积和芦苇群落面积。未筛选得到与5m 等深线以内沙体面积变化有显著相关性的环境因子。九段沙沙体的演变受到了水文、泥沙条件及河势变化的重要影响。同时，沙体的发育提供了适宜植物生长的高程及环境条件进而促进了植被面积的扩张。沙洲演变与植被演变之间的相互作用关系在不同植被和不同高程间有所差异。未来需要进行长期有效监测以系统综合分析水文过程、沙洲演变与植被变化之间的相互作用关系。 相似文献
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福建沿海胃癌高、低发区生态地球化学特征 总被引：1，自引：0，他引：1
通过对长乐市梅花、文岭镇胃癌高发区及福安市下白石镇胃癌低发区的土壤、水体、稻米等介质中元素含量的对比分析,运用数理统计方法对胃癌与生态地球化学环境的关系进行研究。结果表明,胃癌高发区的土壤、稻米中Mo等有益元素缺乏,稻米中Hg、Cd等有害元素较高,饮用水中Cl^-、Mn等有害元素较高。 相似文献
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G. catenatum 《Estuarine, Coastal and Shelf Science》2001,53(6):787
Toxic Gymnodinium catenatum blooms usually occur in the Galician Rias at the end of the upwelling season, which necessitates a ban on harvesting shellfish extraction, with subsequent economic losses for this sector. One of the possible causes cited in the literature is the advection of populations from outside the area but no evidence was available to substantiate this.Oceanographic conditions at the end of the upwelling season in the NW coast of the Iberian Peninsula (39°–43°N) have been studied for the years 1986, 1990, 1995 and 1998. Sea surface temperature data from satellite images, wind data, drifter tracks and in situ oceanic data from the Galician Rias have been combined to clarify the oceanographic structures in the area at the commencement of the blooms. On the inner shelf, an inshore poleward current advecting warm water has been identified after the cessation of upwelling. On the middle and outer shelf, a tongue of cold water as a remnant of the previous upwelling continued to move southward. On the slope and offshore, the poleward counter current reported by several authors was detected carrying warm oceanic water northwards.It is suggested that the inshore poleward current, not previously reported in the literature, could advect initial populations of dinoflagellates to the Rias from northern Portuguese waters. This would explain why blooms such as G. catenatum have been found usually in Portuguese waters several weeks before the Galician Rias, showing an apparent northward movement, but cells of this toxic dinoflagellate species have not been found in waters of the offshore poleward counter current. 相似文献
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Giorgio Bavestrello Riccardo Cattaneo-Vietti Roberto Danovaro Mauro Fabiano 《Marine Ecology》1991,12(4):281-292
Abstract. The detritus rolling down a vertical cliff was studied at Portofino Promontory (Ligurian Sea, Italy) at 16 m depth (January 1988- January 1989). The large amount of collected sediment is mainly due to the position of the traps; they collected not only the sedimenting material, but also the detritus rolling down along the cliff. The amount of sediment matter is 7 times greater in winter than in summer, showing a good correlation with rough seas and rain that cause a "mechanical cleaning" of animal and plant debris (Sérpulid tubes, shells, exuvias. leaves) along the cliff.
The Total Suspended Matter (TSM) in the water column shows maximum values in March and September. The organic fraction has an average concentration of 0.81 mg 1-l . The phytoplanktonic biomass, measured as Chi a , shows an annual cycle with a peak in spring (1–2.7μg·l-1 ). while in other periods of the year the value is about 0.3-0.5 μg·1-1 . A significant relationship was found between organic detritus in the collected sédiments and the Chi a in the water column. The great influence of the rocky wall detritus on the normal trend of the TSM in the coastal water column is pointed out. 相似文献
The Total Suspended Matter (TSM) in the water column shows maximum values in March and September. The organic fraction has an average concentration of 0.81 mg 1
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苏北岸外条子泥沙洲潮沟系统的稳定性研究 总被引：6，自引：2，他引：4
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。 相似文献
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长江口潮间带九段沙浅滩潮水沟形态分析 总被引：3，自引：1，他引：2
潮水沟演化是潮滩滩面对环境动力和生物过程的适应,分析潮水沟的形态特征有助于反推解读滩面的响应机制。借助于滩面水位高程计算模型和参数统计分析,提出九段沙上沙滩面潮水沟存在集中和分散两种发育模式。与分散模式相比,集中模式的水动力条件更强,潮沟数量更少,等级更高,规模更大。在研究区内,单支潮水沟的汇水形式彼此不同,但两种模式的总体汇水形式相近,潮水沟均以显著线性关系随汇水面积增大而扩展,最后两侧滩面产生同等的沟化程度。 相似文献
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渤海湾西岸滨海盐渍土的盐渍化特征分析 总被引：4，自引：0，他引：4
渤海湾西岸滨海盐渍土的盐渍化特征与滨海平原的地面高程、气候条件、盐渍土的理化性状、地下水的矿化度及人类活动等密切相关。就土盐渍化的程度而言,地面高程较高处的土高于地面高程较低处的土,上层土高于下层土。受蒸发和降水影响,地下水位以上土的盐渍化敏感深度为1 m左右。随着气候的变化,滨海盐渍土显现出春季蒸发,上层土积盐;夏季淋洗,土中盐分向下移动的盐渍化特征。随着深度的增加,土的含盐量逐渐减少,至地下水位附近出现轻微增长。从剖面上地表至地下水位间可划分为3个不同聚盐形态和含盐量的土盐渍化程度分区带,即土蒸发浓缩聚盐带、土盐化变动带和土饱水溶盐带;平面上向海岸线方向延伸,土逐渐由非盐渍土变为弱盐渍土、中盐渍土和强盐渍土,含盐量和盐渍化程度也越来越高。地下水位浅和地下水矿化度高,则上层土的盐渍化程度就愈高。 相似文献
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