Microalgal blooms occur in Kuwait's waters year round. Seasonal non-harmful blooms are part of the annual succession in marine ecosystems and are a typical phenomenon in Kuwait's waters as well as in the Gulf region. The ecology and taxonomy of phytoplankton in Kuwait's waters have been studied during the past few decades; however, only very limited detailed taxonomical studies have been done on marine phytoplankton as a whole, as well as on potentially harmful species. Together with the phytoplankton, benthic microalgae are important primary producers and an essential component of the intertidal zone in Kuwait's marine environment. Potentially toxic microalgae were found in the intertidal sediments of Kuwait.
A total of 62 identified taxa can be categorized as potentially harmful species in the collected samples from Kuwait's waters and intertidal flats. Among them, 43 taxa are potentially toxic to humans and marine biota, and 10 taxa are potentially harmful to fish and invertebrates. Potentially toxic species are usually recorded in low densities in Kuwait's waters. However, the presence of a significant number of potentially harmful species in its phytoplankton can be regarded as a significant finding with latent hazards for humans and marine ecosystems. Documentation of this sporadic high abundance together with significant species richness of the potentially toxic phytoplankton, requires more intensive and comprehensive studies of Kuwait's marine environment.