Phytoplankton as a key element in the marine food chain plays a vital role in marine ecosystems. In the South China Sea, phytoplankton blooms often occur northwest of Luzon Island usually during winter, which may have an important impact on primary productivity and regional biological carbon pump. Located in the East Asian monsoon region, the region northwest of Luzon Island is affected by wind stress, Kuroshio and topography with complex dynamic environment. With comprehensive analysis of domestic and international recent studies on phytoplankton blooms in the region northwest of Luzon Island, it is in order to explore the significant impacts of the environmental conditions including wind, Cagayan river discharge, Kuroshio intrusion, upwelling and currents on the spatio-temporal distribution of phytoplankton blooms. It is concluded that the winter phytoplankton bloom is likely due to upwelling and turbulent mixing generated by the Kuroshio interaction with the topography of the Luzon Island. The Cagayan river discharge also contributes to this occurrence, which is the largest river in the Philippines. But the impact of the river is limited to a few kilometers from its mouth. Moreover, the northward flow west of Luzon Island causes the center of the phytoplankton bloom to move northward. This review outlines the impacts of environmental elements on winter phytoplankton blooms northwest of the Luzon Island, and explores potential formation mechanisms of the blooms. Its spatio-temperal distribution can reveal the changes of marine ecosystem indirectly and is of great significance to marine scientific research. The researches on winter phytoplankton blooms also play a guiding role in red tide disaster prevention, marine environmental protection research, fisheries development, to some degree. The more detailed knowledge of the dynamic mechanisms of phytoplankton bloom phenomena contributes to better understanding of the complex marine biogeochemical process near the Luzon Strait.
Ying Chen1,2, Hui Gao1,2 and Hui Zhao1*