Cyanobacteria and Cyanotoxins in Southeast Asia: Ecotoxicology and Management Perspectives

Cyanobacteria are prolific producers of secondary metabolites, some of which are potent cyanotoxins that threaten ecosystem integrity and human health. Although blooms have been extensively studied in temperate regions, Southeast Asia’s (SEA’s) tropical marine and estuarine ecosystems remain comparatively underexplored despite their ecological richness and socio-economic importance. This review consolidates current knowledge on marine cyanobacteria and cyanotoxins in SEA, drawing on ecological surveys, ecotoxicological studies, and cyanobacterial bloom case reports. Diverse taxa including Trichodesmium, Lyngbya, Oscillatoria, Neolyngbya, and Aliinostoc, have been documented in SEA’s marine waters, many producing cyanotoxins with various toxic effects. Ecotoxicological risks are intensified by monsoonal variability, nutrient enrichment, and climate-driven shifts that collectively amplifies cyanoblooms and toxin production. Detection methods such as PCR-based assays, LC-MS/MS, and biosensor technologies are increasingly applied to identify toxin biosynthesis genes, cryptic species, and novel metabolites. Environmental challenges including eutrophication from wastewater discharge, trophic transfer of toxins, and climate induced shifts in species distribution, further complicates bloom dynamics and management. Mitigating this requires a multi-pronged approach: advancing biosensors for rapid detection, embedding monitoring within predictive climate frameworks, and expanding molecular surveillance to capture cryptic diversity and gene transfer events. Such strategies are essential for environmental management of cyanobacterial blooms in SEA.