Based on both physical and biological data collected from multi-source satellite during summer typhoon Linfa, we found that the typhoon triggered two phytoplankton declines and three phytoplankton blooms in the northern South China Sea (SCS), where the waters were influenced by coastal upwelling and the input of terrigenous materials from the Pearl River estuary (PRE). One phytoplankton decline (about a 3-fold reduction) in the continental shelf region can probably be attribute to the limited nutrient supply induced by the decayed coastal northeastern current and onshore Ekman transport (OET) and Kuroshio intrusion water, as well as the uplifted subsurface’s low chlorophyll-a (Chl-a) concentration driven by vertical mixing and upwelling. Another phytoplankton decline (about a 3.5-fold reduction) in the eastern Leizhou Peninsula-coastal upwelling region is probably caused by OET and a decayed coastal northern current. Conversely, the decayed coastal current, OET, and the vertical mixing and upwelling could lead to the transport of nutrient-rich water from the PRE to the nearshore region of the southwestern PRE mouth, and from the subsurface layer to the surface, respectively, thereby stimulating the growth of phytoplankton in the nearshore region (increased by about 4-fold) and the open ocean (increased by about 2.3-fold). In the Shantou (the coastal upwelling region), the phytoplankton responses to nutrient supply were feeble when phytoplankton was already growing in nutrient replete conditions. In addition, the OET and the high turbidity barely resulted in moderate phytoplankton bloom (increased by 38%). In summary, the physical driving forces associated with typhoons that modulates phytoplankton dynamics are the nutrient and phytoplankton transportation in the northern SCS during the wet season.

中文翻译：

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夏季台风琳发对南海北部大陆架区叶绿素a浓度的影响

基于夏季台风“临发”期间多源卫星收集的物理和生物数据，我们发现台风在南海北部（SCS）引发了两次浮游植物减少和三次浮游植物水华，该水域受沿海上升流和来自珠江口（PRE）的陆源物质输入。大陆架区域浮游植物的减少（约减少 3 倍）可能是由于沿海东北流衰减和陆上埃克曼输运 (OET) 和黑潮侵入水以及抬升的地下低叶绿素一个（Chl-一个) 由垂直混合和上升流驱动的浓度。雷州半岛东部沿海上升流区浮游植物的另一次减少（约减少 3.5 倍）可能是由 OET 和衰减的沿海北流引起的。相反，衰减的海岸流 OET 和垂直混合和上升流可能导致富营养水从 PRE 输送到西南 PRE 口的近岸区域，以及从地下层输送到地表，从而刺激近岸地区（增加约 4 倍）和公海（增加约 2.3 倍）浮游植物的生长。在汕头（沿海上升流区），当浮游植物已经在养分充足的条件下生长时，浮游植物对养分供应的反应很弱。此外，OET 和高浊度几乎没有导致中度浮游植物大量繁殖（增加 38%）。总之，与台风相关的调节浮游植物动态的物理驱动力是南海北部雨季期间营养物质和浮游植物的运输。