| 摘要: |
| 夏季大亚湾存在由粤东沿岸上升流所引起的外海水入侵现象，且入侵强度存在年际差异，作者利用大亚湾2004~2017年历年夏季航次调查数据，将弱入侵年份与强入侵年份进行对比分析，以探讨外海水入侵对大亚湾浮游植物群落结构的影响。结果显示，当外海水入侵由弱变强时，湾内水体理化特征发现显著变化，水体由高温低盐转变为低温高盐，N、P等营养盐含量出现下降。海水理化性质的改变导致了浮游植物群落结构的变化，硅藻、甲藻种类数以及浮游植物Shannon-wiener指数均出现升高；浮游植物总丰度和硅藻丰度下降，甲藻丰度变化不明显；常见浮游植物种类伪菱形藻属（Pseudo-nitzschia sp.）、角毛藻属（Chaetoceros sp.）和叉角藻（Ceratium furca）丰度出现下降，而中肋骨条藻（Skeletonema costatum）和菱形海线藻（Thalassionema nitzschioides）丰度出现升高；优势种由单一硅藻种类向硅藻和甲藻共为优势转变。此外，外海水入侵还会通过改变海水理化因子的空间分布以及湾内上层水体流向来影响浮游植物群落结构的空间分布。 |
| 关键词: 大亚湾 外海水入侵 浮游植物 营养盐 |
| DOI：10.11759/hykx20190321003 |
| 分类号: |
| 基金项目:国家科技基础资源调查专项项目（2017FY201404） |
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| Effects of shelf seawater intrusion on phytoplankton community structure in Daya Bay in the summer |
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YANG Xi1,2,3, TANG Ye-hui1,2
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1.South China Sea Institute of Oceanology Chinese Academy of Sciences, Guangzhou 510301, China;2.University of Chinese Academy of Sciencces, Beijing 100049, China;3.South China Sea Environmental Monitoring Center, State Oceanic Administration, Guangzhou 510300, China
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| Abstract: |
| Summer seawater intrusion caused due to coastal upwelling off eastern Guangdong occurs in Daya Bay and exhibits annual variation in its strength. This study analyzed the effects of seawater intrusion on the phytoplankton community structure using summer survey data from 2004 to 2017 in Daya Bay. Results demonstrated that strong shelf seawater intrusion results in low-temperature and high-salinity water in Daya Bay. The concentrations of dissolved inorganic nitrogen (DIN) and phosphate (PO43--P) diluted by the intrusion water decreased, which thereby changed the phytoplankton community structure. The richness of diatoms and dinoflagellates and the Shannon-Wiener index of phytoplankton increased, whereas the total abundance of phytoplankton and diatoms, but not dinoflagellates, decreased. The abundance of regular species such as Pseudo-nitzschia sp., Chaetoceros sp., and Ceratium furca decreased, whereas that of Skeletonema costatum and Thalassionema nitzschioides increased. The dominant group changed from single diatoms to diatoms with coexistent dinoflagellates. Moreover, seawater intrusion also has the potential to change the horizontal distribution patterns of phytoplankton by affecting the horizontal distribution patterns of seawater physicochemical characteristics and the flow direction of upper water. |
| Key words: Daya Bay shelf seawater intrusion phytoplankton nutrients |
