真光层的颗粒动力学──Ⅵ.南海东北部海域上层水体颗粒动力学的示踪研究  

PARTICLE DYNAMICS IN THE EUPHOTIC ZONE Ⅵ.THE UTILITY OF TRACER ^(234)Th FOR STUDYING PARTICLE DYNAMICS IN THE UPPER WATER COLUMN OF THE NORTHEASTERN SOUTH CHINA SEA

作　　者：陈敏[1] 黄奕普[1] 陈飞舟[1] 邱雨生[1] 徐茂泉[1] 姜德盛 

机构地区：[1]厦门大学海洋系,厦门361005

出　　处：《热带海洋》1997年第2期91-103,共13页

基　　金：国家自然科学基金!4945600l;49376272

摘　　要：利用234Th－238U不平衡研究南海东北部海域3个站位上层水体中的颗粒动力学性质，测定了水往中溶解态及颗粒态234Th的比活度，具体讨论各相中234Th／238U）AR（放射性活度比）比值的垂直分布情况及其与水化学要素间的关系。运用稿态箱式模型计算出各站位不同水层中溶解态234Th相对于清除至颗粒物的平均停留时间和颗粒态234Th相对于迁出作用的停留时间。由模型得出的参数表明3个站位的真光层具有两种不同的层化图像，这一情形与我们在南沙群岛海域得到的结果相一致。结合POC／PTh比值，估算出3个站位从真光层输出的颗粒有机碳（POC）通量分别为4.025.0和5．4mmolC·m－3－d-1。文中进一步讨论了234Th与POC两者停留时间的关系。The disequilibrium between the particle -reactive tracer 234 Th (T1/2=24. 1d)and its soluble parent, 238U, was used to study the particle dynamics at three stations in the northeastern South China Sea. Profiles of dissolved and particulate 234Th in the upper 500m and a steady state box model were used to quantify dissolved 234Th scavenging and particle removal rates. Some valuable biogeochemical information have been gained by combination with the profiles of nutrients (NO-3 NO-2, SiO2-3,PO3-2), S, T, DO, TSM and POC The calculated parameters suggested that three stations have two kinds of thoritun structure in the euphotic zone, which is consistent with the conclusion we obtained in the Nansha sea area. The POC export fluxes out of the euphotic zone were 4.0, 25.0 and 5.4 mmol C. m-2. d-1 respectively. The relations between the residence times of POC and PTh have also been discussed.

关 键 词：颗粒动力学 真光层 表层水 南海 铀238 钍234 

分 类 号：P734.24[天文地球—海洋化学] P731.2[天文地球—海洋科学]