Light spectrum regulates cell accumulation during daytime in the raphidophyte Chattonella antiqua causing noxious red tides.

Most marine raphidophyte species cause noxious red tides in temperate coastal areas around the world. It is known that swimming abilities enable raphidophytes to accumulation of cells and to actively acquire light at surface layers and nutrients over a wide depth range. However, it remains unclear how the swimming behavior is affected by environmental conditions, especially light condition.