Dinophysis

Dinophysis is a genus of marine dinoflagellates in the family Dinophysiaceae, class Dinophyceae. They are single-celled, planktonic microalgae that occur in temperate and subtropical coastal waters worldwide. Some species form noticeable blooms that can impact shellfish industries.

Biology and ecology: Dinophysis species are primarily mixotrophic, feeding on other plankton and often acquiring photosynthetic plastids from prey through kleptoplasty. They are characterized by the typical dinoflagellate cell organization, with two flagella that enable movement in the water column. Species composition and abundance can vary regionally and seasonally, with blooms often linked to nutrient-rich upwelling areas.

Toxins and health effects: Several Dinophysis species produce lipophilic toxins associated with diarrhetic shellfish poisoning (DSP). The toxins include okadaic acid (OA) and dinophysistoxins (DTX1–DTX4), as well as pectenotoxins. OA and DTXs inhibit protein phosphatases in human cells and can cause gastrointestinal symptoms in people who consume contaminated shellfish.

Distribution and impact: Dinophysis blooms are reported worldwide, particularly in coastal zones where upwelling or eutrophic conditions occur. Toxin accumulation in shellfish such as mussels, clams, and oysters can lead to harvest closures and public-health advisories, prompting routine monitoring programs.

Detection and monitoring: Monitoring combines phytoplankton surveillance for Dinophysis cell counts with toxin analyses in shellfish tissue, typically by liquid chromatography–mass spectrometry (LC-MS). Molecular methods and advanced imaging are increasingly used to identify species and track bloom dynamics.