Progress in remote sensing identification of algal species in global water bodies

Algal blooms pose a serious threat to public health, aquatic ecological security, regional economic development, and have become a global water ecological and environmental issue. The causes of algal blooms are complex, with different types of algae leading to varying impacts. Among these, the species of phytoplankton and their dominant populations are critical factors in assessing the ecological health and safety of water bodies. While traditional laboratory methods can provide high-precision algal identification information, satellite remote sensing technology offers the advantages of real-time and large-scale monitoring, enabling the dynamic observation of algae in global water bodies. Although existing studies have utilized remote sensing technology to identify algae, its operational application still faces numerous challenges. This article reviews the research progress in algal species identification, remote sensing monitoring of specific algae, and the differentiation of mixed algal species. Overall, satellite remote sensing has been proven effective in identifying and monitoring algae across different phyla. Based on differences in the inherent optical properties or apparent optical properties of water bodies, various algal identification methods have been developed. However, research on fine-scale identification of differences among various algal species remains relatively limited. Further investigation into the optical property differences among different algae is key to improving algal identification efficiency. Future research on remote sensing identification of algal species will advance in the directions of refined algorithms, quantitative inversion of algal biomass, large-scale spatiotemporal analysis, and operational applications. This review aims to provide references for related studies in water environment monitoring, algal bloom early warning, and prevention and control.