莱州湾表层海水水化学要素分析

发布时间：2018-05-23 15:13

本文选题：莱州湾 + 营养盐　；参考：《中国地质大学（北京）》2014年硕士论文

【摘要】：莱州湾是我国典型的半封闭性陆架海湾，入海径流丰富，营养盐充足，是我国重要的鱼、虾、蟹产卵场和索饵场之一，也是我国北方重要的渔业生产基地。进入新世纪以来，莱州湾地区工、农业快速发展给莱州湾生态环境带来了沉重的压力。我们于2012年8月对莱州湾海域进行了综合水质调查，分析了莱州湾表层水体理化因子、营养盐、常量元素和微量元素水平分布特征和相关性，并对海水进行聚类分析、富营养化评价和重金属污染风险评价。最后，结合沿岸地下水、河水水化学数据，初步分析莱州湾营养盐和重金属入海途径。主要结论如下：沿岸淡水输入是莱州湾海水化学要素水平分布的主要影响因素。莱州湾表层海水pH、盐度、比重、TDS、电导率、K、Mg、Na、Ca、Sr、Cl、S、Li有着相似的水平分布特征，均呈现出沿岸低、湾内高的分布特点，从湾口向湾内有减小趋势，，在河口处最小。海水深度是海水温度的主要控制因素，海水温度由近岸向湾内随海水深度增加降低；DO（溶解氧）含量主要受海水温度影响，随温度升高DO含量降低。湾口海域海水理化因子垂向变化无明显特点。海水化学要素相关性分析显示盐度、比重、TDS、电导率、K、Mg、Na、Ca、Sr、Cl、S之间有着很好的正相关关系；通过聚类分析将莱州湾海水划分为东、西两个部分，东部受到渤海海水影响明显，西部受到沿岸淡水输入影响明显。莱州湾海水富营养化水平为磷限制潜在性富营养，N/P原子比为189.06，近年来莱N/P比值居高不下，随着海水磷消耗而氮富余，N/P值有继续增大的可能。莱州湾存在重金属污染风险，污染风险大小排列依次为Cu Ni Co，重金属As和Cr符合二类海水水质标准。由于资料有限，本文无法确定莱州湾部分海域重金属含量偏高原因,其入海途径需要进一步调查。莱州湾营养盐主要来自沿岸河流淡水输入，海底地下水排泄也是莱州湾营养盐的重要来源。初步估算结果显示，沿岸河流向海输送DIN:1.03×106t/a，P：6.24×104t/a，海底地下水排泄的营养盐通量为DIN:1.26×105t/a，P：2.75×103t/a。海底地下水排泄向海输送陆源污染物的能力不可忽视。
[Abstract]:Laizhou Bay is a typical semi-closed shelf bay in China with abundant runoff and abundant nutrients. It is one of the important spawning grounds for fish, shrimp, crab and bait field in China, as well as an important fishery production base in the north of China. Since the beginning of the new century, the rapid development of agriculture in Laizhou Bay has brought heavy pressure to the ecological environment of Laizhou Bay. In August, 2012, we conducted a comprehensive water quality survey in Laizhou Bay, and analyzed the distribution characteristics and correlation of physical and chemical factors, nutrients, major elements and trace elements in the surface water of Laizhou Bay, and carried out cluster analysis of sea water. Eutrophication evaluation and heavy metal pollution risk assessment. Finally, combined with the chemical data of groundwater and river water along the coast, the nutrient and heavy metals in Laizhou Bay were preliminarily analyzed. The main conclusions are as follows: Coastal fresh water input is the main factor influencing the horizontal distribution of seawater chemical elements in Laizhou Bay. The pH, salinity, specific gravity and conductivity of the surface seawater in the Laizhou Bay have similar horizontal distribution characteristics, showing the characteristics of low littoral and high in the bay, decreasing from the mouth of the bay to the inside of the bay, and the smallest at the mouth of the estuary. The depth of seawater is the main controlling factor of seawater temperature. The content of do decreases with the increase of seawater depth, and the content of do decreases with the increase of seawater depth. The vertical change of physical and chemical factors of seawater in the gulf is not obvious. The correlation analysis of sea water chemical elements shows that there is a good positive correlation between salinity, specific gravity, TDS and electrical conductivity, and the sea water in Laizhou Bay is divided into east and west parts by cluster analysis, and the eastern part is obviously influenced by Bohai sea water. The west is obviously affected by the coastal fresh water input. The eutrophication level of seawater in Laizhou Bay is phosphorus limiting potential eutrophication N / P atomic ratio is 189.06. In recent years, the ratio of N / P to N / P remains high, and the N / P value of nitrogen surplus is likely to continue to increase with the consumption of phosphorus in seawater. Heavy metal pollution risk exists in Laizhou Bay. The order of pollution risk is that Cu Ni Co, heavy metals as and Cr conform to the second class seawater water quality standard. Because of the limited data, it is impossible to determine the reason for the high content of heavy metals in some sea areas of Laizhou Bay, and the way to enter the sea needs further investigation. The nutrient in Laizhou Bay mainly comes from the fresh water input of coastal rivers, and the discharge of undersea groundwater is also an important source of nutrients in Laizhou Bay. The preliminary estimation results show that the coastal rivers transport DIN:1.03 脳 106t / a to the sea with a nutrient flux of DIN:1.26 脳 105t / a: 2.75 脳 103t / a, and the nutrient flux of the undersea groundwater is 6.24 脳 104t / a. The ability of undersea groundwater to discharge and transport land-based pollutants to the sea cannot be ignored.
【学位授予单位】：中国地质大学（北京）
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P734.41

【参考文献】