The influence of turbulent mixing on the subsurface chlorophyll maximum layer in the northern South China Sea
The influence of turbulent mixing on the subsurface chlorophyll maximum layer in the northern South China Sea
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湍流混合对南海北部次表层叶绿素最大层的影响
DOI：
10.1007/s00343-020-0313-1
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发表时间：
2021
影响因子：
1.6
通讯作者：
Gao Yongli
中科院分区：
文献类型：
--
作者：
Shang Chenjing;Liang Changrong;Chen Guiying;Gao Yongli
我们提供了 2010 年 4 月至 5 月在南海北部部署湍流微观结构仪器和 CTD 包的观测结果。从中我们确定了两个横断面（A 和 B）中的湍流混合（耗散率 ε 和二密扩散系数 κ）、营养物（磷酸盐、硝酸盐和亚硝酸盐）、营养物通量和叶绿素 a。横断面A位于上部100 m湍流混合较弱的区域(κ ~10 ~(-6) -10 ~(-4) m~2/s)。 B断面位于上层100 m湍流混合较强的区域（κ ~10 ~(-5) -10 ~(-3) m~2/s），受吕宋海峡内波和西太平洋海水入侵的影响。在这两个样带中，在上部 100 m 处都有一个薄的地下叶绿素最大层 (SCML) (>0.25 mg/m~3)。观察结果表明，湍流混合对两条样带中养分和叶绿素a分布的影响是不同的。在湍流混合较弱的样带 A 中，湍流混合引起的营养物通量将营养物输送到 SCML，但不输送到上层水域。营养物质足以支持当地 SCML 浮游植物种群，并且 SCML 保持紧凑。在湍流混合较强的B样带中，湍流混合引起的营养盐通量不仅将营养盐输送到SCML，而且将营养盐输送到上层水体，使水柱中的营养盐分散并使SCML扩散。
We present observations from deployments of turbulent microstructure instrument and CTD package in the northern South China Sea from April to May 2010. From them we determined the turbulent mixing (dissipation rate ε and diapycnal diffusivity κ), nutrients (phosphate, nitrate, and nitrite), nutrient fluxes, and chlorophyll a in two transects (A and B). Transect A was located in the region where turbulent mixing in the upper 100 m was weak (κ ~10 ~(-6) -10 ~(-4) m~2/s). Transect B was located in the region where the turbulent mixing in the upper 100 m was strong (κ ~10 ~(-5) -10 ~(-3) m~2/s) due to the influence of internal waves originating from the Luzon Strait and water intrusion from the Western Pacific. In both transects, there was a thin subsurface chlorophyll maximum layer (SCML) (>0.25 mg/m~3) nested in the upper 100 m. The observations indicate that the effects of turbulent mixing on the distributions of nutrients and chlorophyll a were different in the two transects. In the transect A with weak turbulent mixing, nutrient fluxes induced by turbulent mixing transported nutrients to the SCML but not to the upper water. Nutrients were sufficient to support a local SCML phytoplankton population and the SCML remained compact. In the transect B with strong turbulent mixing, nutrient fluxes induced by turbulent mixing transported nutrients not only to the SCML but also to the upper water, which scatters the nutrients in the water column and diffuses the SCML.