Molecular techniques for understanding harmful algal blooms: A review

Harmful algal blooms (HABs) are intricate ecological events caused by diverse algal species and are influenced by a myriad of biotic and abiotic factors. The urgently needed development of effective prevention and control techniques face two primary challenges. The first challenge is the technical shortfalls in rapidly identifying and monitoring the causative species. The second challenge is the absence of research frameworks and technologies for accurately diagnosing the primary drivers of these blooms. Molecular techniques offer promising solutions to these issues, and research in this field has seen significant growth over the past two decades. Previous reviews have predominantly focused on species identification and monitoring, leaving the status of bloom driver studies less clear. This review provides a comprehensive overview of molecular techniques for HAB identification and driver analysis. HAB-specific use cases of techniques and comparison between them based on technical specifications are provided. Nucleic acid-based techniques presently dominate over antibody-based techniques due to their tunable taxon-specificity and ease to prepare probes. In situ applications and monitoring platforms still have a large room for improvement. The omics approach is the most promising choice for unraveling HAB drivers but requires a framework and a quantitative model for estimating the contribution of potential responsible factors. Future prospects relating to particular needs in HAB research and emerging technologies are also discussed.