A review of the current and emerging detection methods of marine harmful microalgae

In recent years, the scale and frequency of outbreaks of harmful algal blooms (HABs) have increased year by year due to the intensification of seawater eutrophication and global climate change. HABs have become a global marine ecological and environmental problem, which poses a serious threat to human health, marine ecological security, and economic development. The establishment of detection technology for harmful microalgae is fundamental to the early warning and prevention of HABs. To date, several detection methods have been developed for harmful microalgae, they however lack a unified classification standard. It is difficult to use a reasonable mix of all the developed methods to improve the accuracy of detection results. Here, all of the established detection methods for harmful microalgae were reviewed, including morphological structure-based detection methods, cytochrome-based detection techniques, immunoassays, and nucleic acid-based detection methods. The principles, advantages, and weaknesses of these methods were highlighted. Their application in the detection of harmful microalgae was summarized. Overall, different detection methods are suitable for different purposes. Further development of more accurate, cost-effective, efficient, and rapid detection technology is required in the future. This review is expected to provide a reference for research related to the monitoring of marine environment, early warning of HABs, and the molecular identification of harmful microalgae.