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991.
长江河口悬浮泥沙向浙闽沿岸输运近期变化的遥感分析   总被引:2,自引:0,他引:2  
陈瑞瑞  蒋雪中 《海洋科学》2017,41(3):89-101
利用2000~2015年Terra-MODIS(terra-moderate resolution imaging spectroradiometer,中等分辨率成像光谱仪)数据和2014年洪枯季现场数据建立泥沙反演模型,分析入长江河口泥沙大幅减少后河口表层悬沙向浙闽沿岸输运的时空变化和扩散形态。结果表明:(1)利用MODIS数据的二次型模型能够揭示长江口及邻近海域悬沙分布及输运特征,入海输运的长江口悬浮泥沙是浙闽沿岸连续悬浮泥沙带存在的物源;(2)受季风和沿岸流动力驱动,长江口悬沙向浙闽沿岸输运具有明显的季节性:春季,悬浮泥沙从长江口向浙闽沿岸呈条带状输运,春夏之交,南下的悬沙至温岭近岸海域出现中断现象;夏季,长江口大量悬沙滞留在长江口杭州湾近岸,仅有少量悬沙向南输运,泥沙带中断;秋季,10月下旬—11月中旬逐渐形成连续的近岸泥沙带;历冬至春,循环复始;(3)受近年来长江流域进入河口的泥沙减少影响,浙闽沿岸秋冬季连续的输沙带在春季提前断开,在秋季有推迟恢复的现象。本研究对于探究浙闽沿岸泥沙减少新格局,分析近海生态环境新变化具有重要意义。  相似文献   
992.
Frequency distribution characteristics of trace elements Fe. Mn, Zn, Cu. Sr and Ba are studied for the marine organisms collected from typical Chinese coastal waters and compared with those of major elements Ca and Mg. Nearly all the distributions for trace elements in macroalgae, benthic molluscs, crustaceans, cephalopods and different tissues of fish (muscle, liver and bone ) are found to show some degree of positive skewness, indicating a relatively large number of marine organisms with low concentrations for a particular element and only a few organisms with disproportionately high concentrations. Their distribution types are generally logarithmic normal distribution or nearly logarithmic normal distribution. Distribution of Ca is similar to that of trace elements, while Mg shows normal distribution. Average elemental concentrations of major types of organisms are calculated based on their frequency distributions.  相似文献   
993.
The abiotic typology of Polish lakes, compliant with the requirements of the EU Directive 2000/60/EC (Water Framework Directive), was developed in 2004 under the commission of the Ministry of the Environment. Based on the combination of the obligatory typological criteria from Annex II of the WFD and one additional factor, all Polish lakes larger than 0.5 km2 were assigned to 13 abiotic types. This typology reflected the diversity of abiotic conditions and was assumed to be tested and validated for its ecological relevance on the basis of biological data obtained thereafter. The first ten years of its application proved the high usability of this typology for lake classification of ecological status on the one hand, while on the other hand, it allowed to gather experiences and to detect deficiencies and errors considered in the verification process. In 2015, the abiotic typology of Polish lakes was verified. Above all, verification involved an analysis of the justification of lake eco-regional division and refinement of water stratification criteria, as these two issues have been questioned in the current typology. Data on physicochemical properties, phytoplankton, macrophytes and benthic diatoms obtained from the state lake monitoring conducted in the years 2007–2013 were used to verify the ecological relevance of the typological criteria. Typological criteria used in the verified lake typological scheme were essentially the same as those used in 2004. However, the number of lake types has been reduced from the previous 13 to seven, mainly due to the withdrawal from the lake division based on eco-regions. Moreover, the more specific criteria for determining the water mixing type were established. The new lake typology is expected to be implemented in routine monitoring and water management in Poland in the forthcoming River Basin Management Plan 2021–2027.  相似文献   
994.
The West Henan large sliding structure is located in the southern part of the North China plate. It is a planar structural feature of a relatively large scale. To its northwest lie the Taihang Mountains, and to the southwest the Funiu Mountain. In the east it extends between the broad plain and hilly land. Formed in the early Indosinian Period, its main sliding surface is the coal seam II 1 with the sliding direction from NW to SE, and a sliding area of about 23,000 km2. Affected by the big sliding, the coal seam II1 in West Henan occurs in the state of powder, and thickens to the SE. Some small penetrating sliding structures were developed over II 1 in the early Yanshanian Period, causing a disorder on the south border of the North China coal-accumulating basin in the late Palaeozoic Era. An exploration into the West Henan large sliding structure is of great importance in the geological study.  相似文献   
995.
朱岳年 《沉积学报》2000,18(4):567-572
油田水体系的地球化学场中蕴含着丰富的石油地质学含意,其研究对指导油气勘探和开发有重要的意义。辽河盆地西部凹陷欢-双地区下第三系油田水可划分为六个体系,即:(1)沙四段油田水体系,(2)沙三段下部油田水体系,(3)沙三段中-上部油田水体系,(4)沙二段油田水体系,(5)沙一段油田水体系和(6)东营组油田水体系。虽然这六个体系的油田水均为低矿化度的重碳酸钠型水,但其矿化度和还原系数场不尽相同;这些不同不仅表现在油田水体系之间的地球化学场异常区面积有差异,而且地球化学场异常区位置也有变化。一般认为油田水体系中矿化度场的正异常区和还原系数场的负异常区为有利的油气聚集区和保存区。  相似文献   
996.
红海湾海水养殖水域的营养盐、盐度、温度、浮游植物和叶绿素的观测结果表明,该水域中氨氮、亚硝酸盐及磷酸盐的消长受水系混合所制约。春季硝酸盐、氨氮和秋季磷酸盐与浮游植物之间存在着负相关,秋季表层叶绿素与营养盐(除氨外)存在着正相关,而底层叶绿素与营养盐存在密切负相关  相似文献   
997.
1986年秋日本以南和以东海域仔稚鱼的分布   总被引:2,自引:0,他引:2  
1986年10~11月在日本以南和以东海域的41个测站进行了鱼卵、仔鱼的调查,共采集到996尾仔稚鱼,它们隶属于38科67种,经济鱼类仔鱼稀少,而大洋性发光鱼类仔鱼十分丰富,其中钻光鱼科和灯笼鱼科分别占仔鱼总数的50.50%和32.33%。优势种为细钻光鱼、串灯鱼和西明灯鱼,它们分别占仔鱼总数的25.30%,16.47%和7.53%。仔鱼的丰度在黑潮流轴外侧边缘及其邻近的大洋域最高,在日本以南的沿岸水域占第二位,而在日本以东的混合水域最低。仔鱼丰度与温、盐度之间有显著的正相关关系。  相似文献   
998.
高抒 《海洋学研究》2021,39(4):1-10
长江入海物质在东海内陆架水域形成了大规模泥质沉积区。内陆架泥区具有细颗粒沉积物和有机质的源/汇双重特征。长江口及邻近海域的泥质沉积过程 产物关系、泥质沉积在生态系统动力学中的作用、泥质沉积碳库增量潜力,是区域性沉积动力学的3个前沿问题,主要研究内容包括长江河口泥区未来演化趋势、泥区沉积物重力流形成条件和过程、泥区沉积物有机质含量与初级生产及低氧水层的关系、泥区消浪作用及其机制、颗粒态有机质衰减曲线(或曲线族)、颗粒态有机质碳库增量潜力等。其研究需要海洋观测站网在底部边界层、水层、新型数据上的支撑,以满足数据分辨率、连续性的要求。底部边界层连续观测将有助于重力流、泥区消浪作用、湍动影响下的沉积物起动曲线族等问题的解决。水层观测将有助于有机质衰减系数的研究,进而获得有机质埋藏率、浅层天然气、有机碳库增量等问题的答案。一些新型数据含有物源、沉积体特征和演化的大量信息,此类数据的获取将依赖于观测技术的突破。  相似文献   
999.
互花米草作为入侵物种对潮间带滩涂和盐沼具有严重的生态危害,化学方法治理互花米草具有简便、快速、彻底和成本低等特点。但化学药剂存在一定毒性,可能会对周边环境带来一系列不利影响。然而,有关化学治理措施所带来环境影响的研究较少。本文基于2017年8-11月的调查数据,研究了天津市永定河河口附近滩涂互花米草化学治理对附近海域海水水质和潮间带沉积物产生的影响,对调查海域海水水质和沉积物质量进行了评价。调查与评价结果表明,无机氮、活性磷酸盐和化学需氧量(COD)为调查海域主要污染因子,硫化物为潮间带沉积物主要污染因子。施药后特征污染物草甘膦检测值高于本底值,所有站位均未检出磺酰脲类除草剂。综合来看,化学治理对附近海域海洋环境影响较小。  相似文献   
1000.
This paper presents the status of summer oxygen conditions in estuarine and coastal waters around Ireland between 2003 and 2007. Of the 95 water bodies surveyed, 85 had oxygen levels sufficient to support aquatic life. This corresponds to a surface area of 3125 km2 or 99.4% of the total area assessed. Ten water bodies, representing a surface area of 20.2 km2, were deficient in oxygen but still capable of supporting most aquatic life. No evidence of hypoxia (<2.0 mg/l O2) or anoxia (<0.2 mg/l O2) was found. Dissolved oxygen conditions in a number of estuaries continue to improve, probably due to improved municipal waste water treatment. The implementation of measures contained in both the Nitrates and Urban Waste Water Treatment Directives, together with those of the Water Framework Directive, should ensure areas of oxygen deficiency are eliminated from Irish waters.  相似文献   
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