| 摘要: |
| 湍流扩散过程导致的硝酸盐垂向输运对海水表层的浮游植物生长和初级生产力的大小有着重要影响。本文基于2018年夏季黄、东海水文环境、硝酸盐浓度和湍动能耗散率的同步、原位数据，分析了海域温度、盐度和硝酸盐的空间分布特征，结果表明营养盐含量丰富的黄海冷水团、长江冲淡水、东海北部底层混合水与黑潮次表层水是影响研究海域硝酸盐分布的主要水团。利用垂向湍扩散硝酸盐通量公式，计算了三个选定断面上的硝酸盐垂向扩散通量，其高值区与湍流扩散系数的高值区的位置基本一致。针对存在明显硝酸盐跃层的站位，计算得到跨硝酸盐跃层的垂向通量FND的范围在-9.78—36.60mmol/（m2·d）之间，在黄海冷水团区，夏季温跃层限制了该区营养盐向近表层的湍流垂向扩散；东海北部底层混合水区，湍流垂向扩散向上层补充了大量硝酸盐，促进了跃层之上浮游植物的生长；黑潮次表层水影响海区，夏季中层水体混合较弱，跨跃层的垂向通量也普遍偏低。开展硝酸盐垂向扩散通量的计算与分析，对进一步明确营养盐的输运机制有着重要研究意义。 |
| 关键词: 硝酸盐 湍流扩散 垂向扩散通量 新生产力 黄东海 |
| DOI：10.11693/hyhz20200100033 |
| 分类号:P731.1 |
| 基金项目:国家重点研发计划项目，2016YFA0601301号；国家自然科学基金，41876018号；天津市自然科学基金，19JCZDJC40600号。 |
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| SUMMER VERTICAL TURBULENT NITRATE FLUX IN THE YELLOW SEA AND THE EAST CHINA SEA |
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LYU Wen-Jin1, SUN Qun1, WANG Si-Jia1, LI Bo-Zhi2
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1.College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin 300457, China;2.Qingdao NORTEK measuring equipment co. LTD, Qingdao 266071, China
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| Abstract: |
| Nitrate vertical transport caused by turbulent diffusion has an important effect on phytoplankton growth and primary productivity of the upper ocean. Based on the synchronously in-situ observation dada of hydrologic feature, nitrate concentration, and the turbulent dissipation rate in summer 2018 in the Yellow Sea (YS) and the East China Sea (ECS), the distributions of temperature, salinity, and nitrate concentration were analyzed. Results show that the main water masses affecting the distribution were eutrophic Yellow Sea Cold Water Mass (YSCWM), the Changjiang Diluted Water (CDW), the Northern East China Sea Bottom Mixed Water (NECSBMW) and the Kuroshio Sub-Surface Water (KSSW). The vertical nitrate fluxes in three selected sections were calculated by using the vertical turbulent diffusion formula; the positions of large fluxes were consistent largely with the large turbulence diffusivity. In the presence of nitracline, the vertical turbulent nitrate flux (FND) across the nitracline ranged from -9.78 to 36.60mmol/(m2·d). In the area influenced by YSCWM, the summer thermocline restricted the vertical turbulent diffusion of nutrients to the surface layer. In the NECSBMW area, the vertical turbulent diffusion supplied a large amount of nitrate to the upper layer and promoted the growth of phytoplankton. In the KSSW area, the mixing of middle-layer water was weak, and the FND was low. The calculation and analysis of the summer vertical turbulent nitrate flux is of great significance to further clarify the transport mechanism of nutrients. |
| Key words: nitrate turbulence diffusivity vertical turbulent nitrate flux new production the Yellow Sea and the East China Sea |
