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Marine Animal Encyclopedia

Dinophysis acuta

Dinophysis acuta is one of the largest belonging to the genus Dinophysis. It is plantlike in having numerous yellow-green chloroplasts, which it uses to manufacture food by photosynthesis, but it is also animal-like in being able to move using its two whiplike flagella for propulsion. Dinophysis acuta's cells are oblong in shape, rounded posteriorly, and have a robust, laterally compressed test that is made up of a number of different plates. Like diatoms, most dinoflagellates have unique tests by which they can be identified even as fossils. All species of Dinophysis are toxic and have been responsible for a number of die-offs in shellfish when blooms occur. Under certain conditions, such as a long period of calm weather, they multiply very rapidly by simple division, sometimes becoming so numerous that the water changes color. This phenomenon is referred to as a red tide. A huge amount of toxins and okadaic acid builds up in the water and passes up the food chain via shellfish in which the toxins accumulate. If the contaminated shellfish is then eaten by humans, it causes sickness and severe diarrhea. Sexual reproduction in Dinophysis acuta is not well understood, but it is thought to involve cells that in the past were described as a different species, Dinophysis dens.

  • Kingdom Dinoflagellata
  • Length Up to in (0.95 mm)
  • Habitat Open water
  • Distribution Cold and temperate waters worldwide