利用镭环境同位素评估胶州湾海底地下水排泄及其携带营养物质输入

发布时间：2018-03-14 00:24

本文选题：海底地下水排泄　切入点：镭同位素　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：海底地下水排泄量(submarine groundwater discharge,SGD)是指通过陆架边缘所有由海底进入海水中的水流,不考虑流体组分和驱动力如何。海水渗入到海岸含水层以后会发生一系列的生物化学反应,从而改变原来海水中的某些化学组分,因此SGD对海岸带生态环境有很好的指示作用。胶州湾作为青岛的母亲湾,是一个湾口很窄的半封闭形海湾,与外海海水的交换能力比较弱。随着经济的高速发展,海湾环境日益遭受人类活动的影响而不断的恶化。因此,研究胶州湾的海底地下水排泄及其携带的营养盐对于胶州湾生态环境意义重大。本研究利用镭同位素质量平衡模型评估了胶州湾的水体刷新时间以及SGD,在此基础上,结合水盐平衡模型评估了胶州湾的海底地下淡水排泄量(submarine fresh groundwater discharge,SFGD),进一步研究了胶州湾的水体混合过程。同时我们结合水体表观年龄模型和纳潮量法对用镭同位素法估计的胶州湾海水的水体刷新时间进行了验证,用区域水均衡法对胶州湾的海底地下淡水排泄量进行了验证。根据上述物理模型,估计得到胶州湾夏季(2015年7月)和冬季(2016年1月)的水体的刷新时间分别为6.06~13.32天、9.32~23.08天,SGD分别为1.16×10~7 m3/d~1.81×10~7 m3/d,0.72×10~7 m3/d~1.11×10~7 m3/d,SFGD分别为0.76×106 m3/d~5.69×106m3/d,1.34×106 m3/d~2.84×106 m3/d。夏季和冬季SFGD占SGD的百分比分别为6.53%~31.40%,18.46%~25.63%。在上述结果的基础上,我们还分析了胶州湾在两个季节的营养盐入海通量。胶州湾夏季近岸地下水的无机氮(DIN)浓度为714.47μmol/L,溶解无机磷(DIP)浓度为0.31μmol/L,氮磷比为2304;冬季DIN浓度为69.40μmol/L,DIP浓度为0.66μmol/L,氮磷比为105。则胶州湾夏季DIN的入海通量为1.04×10~7 mol/d,DIP的入海通量为4.49×10~3 mol/d,冬季DIN的入海通量为6.21×105 mol/d,DIP入海的通量为5.91×10~3 mol/d。
[Abstract]:Submarine groundwater charge (SGD) refers to all currents entering seawater from the bottom of the shelf through the edge of the shelf, regardless of the composition and driving force of the fluid. A series of biochemical reactions occur when seawater seeps into a coastal aquifer. In order to change some chemical components in the original seawater, SGD is a good indicator of the ecological environment of the coastal zone. As the mother's bay of Qingdao, Jiaozhou Bay is a narrow semi-enclosed bay. With the rapid development of economy, the environment of the Gulf is increasingly affected by human activities. It is of great significance to study the discharge of groundwater in Jiaozhou Bay and its nutrients for the ecological environment of Jiaozhou Bay. In this study, the water refresh time and SGD of Jiaozhou Bay were evaluated by using radium isotope mass balance model. Combined with water and salt balance model, the submarine fresh groundwater discharges SFGDN were evaluated in Jiaozhou Bay, and the mixing process of water body in Jiaozhou Bay was further studied. At the same time, radium isotopes were applied to Jiaozhou Bay in combination with the apparent age model of water body and the method of tidal absorption. The water refresh time of Jiaozhou Bay sea water was verified by the method. The regional water balance method is used to verify the discharge of underground fresh water from the bottom of Jiaozhou Bay. The estimated refreshment times for summer (July 2015) and winter (January 2016) in Jiaozhou Bay were 6.06 ~ 13.32 days and 1.16 脳 10 ~ 7 m ~ (3 / 3) / d ~ (1.81) 脳 10 ~ (7) m ~ (3 /) d ~ (-1) d ~ (-1) 7 脳 10 ~ (7) mm ~ (3) / d ~ (-1), respectively, respectively. The mean values of SFGD in SGD in summer and winter were 0.76 脳 10 ~ (6) m ~ (3 / 3) and 5.69 脳 10 ~ (6) m ~ (-3) d ~ (-1) 2.84 脳 10 ~ (-6) m ~ (3d) d, respectively. The percentages of SFGD in SGD in summer and winter were 6.5331.40 ~ 18.46m ~ (3) g / d respectively. Based on the above results, The nutrient flux of Jiaozhou Bay in two seasons was also analyzed. The concentration of inorganic nitrogen tin, dissolved inorganic phosphorus, nitrogen and phosphorus were 714.47 渭 mol / L, 0.31 渭 mol / L, 2304, and 69.40 渭 mol / L, 0.66 渭 mol / L, 0.66 渭 mol / L, respectively, in the summer of Jiaozhou Bay, 69.40 渭 mol / L and 0.66 渭 mol / L, respectively, and the ratio of nitrogen and phosphorus to nitrogen and phosphorus was 0.31 渭 mol / L, 69.40 渭 mol / L and 0.66 渭 mol / L, respectively. In the summer of Jiaozhou Bay, the flux of DIN is 1.04 脳 10 ~ (7) mol / d ~ (-1) and that of DIN in winter is 6.21 脳 10 ~ (5) mol / d ~ (3) mol 路d ~ (-1) ~ (-1) ~ (-1) 脳 10 ~ (-3) mol 路d ~ (-1).
【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】：2017
【分类号】：X145;P731.2

【相似文献】