The East China Sea (ECS) is threatened by frequent Skeletonema costatum (S. costatum)blooms every year, which can cause severe environmental harm, as well as considerableeconomic losses. Remote sensing is an efficient tool for monitoring these harmful algal blooms(HABs) and studying concerned marine conditions. This study investigated two intensiveS. costatum HABs in the ECS by analysis of water distribution and spatial-temporal patternof four oceanographic parameters derived from moderate resolution imaging spectroradiometer(MODIS) and QuickSCAT satellite data using multiple remote sensing approaches (compositeimagery interpretation, classification, and parameters retrieval). Results show that high chlorophyll-a (Chl-a) concentrations and net primary production (NPP) decrease from the HABareas toward the open sea. A peak of Chl-a (<10 mgm−3) and NPP (<5000 mg · C · m−2 · d−1)are considered indicators of large-scale S. costatum blooms in the ECS. Low sea surfacetemperature (SST; approximately 23°C) are observed in S. costatum HAB areas. In early stages,winds in terms of direction and speed can bring nutrients to facilitate the formation of S. costatumblooms, but then sharply change into unfavorable conditions to cause the final disappearanceof HABs. This study also explored multiple oceanographic explanations in the ECS frombiochemical, meteorological, physical, and geological perspectives for a better understanding ofsuch S. costatum HABs mechanisms.
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