Seasonal distribution of species of the toxic dinoflagellate genus Dinophysis in Maizuru Bay (Japan), with comments on their autofluorescence and attachment of picophytoplankton

Goh Nishitani, Hikaru Sugioka, Ichiro Imai

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

The seasonal distribution of the dinoflagellate genus, Dinophysis, in Maizuru Bay, Japan, was investigated from May 1997 to December 1999. Seven species of Dinophysis were detected, including the toxic species of Dinophysis acuminata and D. fortii. The most dominant species was D. acuminata, detected year-around and more abundantly during periods when water temperatures were between 15 and 18°C. No relationship was found between cell abundance of Dinophysis spp. and concentrations of dissolved inorganic nutrients. Phycoerythrin containing nano- and picophytoplankton (cryptophytes and cyanobacteria), suspected to be prey of mixotrophic Dinophysis, were enumerated simultaneously. A clear relationship was not found among the cell abundances of Dinophysis spp. and nano- and picophytoplankton. Autofluorescence of Dinophysis spp. (mainly D. acuminata and D. fortii) under blue-light excitation was usually of a yellow-orange color. Occasionally, Dinophysis spp. had red autofluorescencing and yellow-orange autofluorescencing particles. The proportion of cells possessing red autofluorescence tended to be higher in the warm season. Numerous coccoid cells of picophytoplankton (ca. 1-2μm in diameter) were found attached to the cell surface of D. acuminata, D. fortii, etc. and food vacuole-like structures also observed. These observations suggest there is a close relationship between mixotrophic Dinophysis spp. and certain picophytoplankton. Based on our observations, the possibility that the picophytoplankton found to be attached onto Dinophysis cell surfaces are a food source for Dinophysis, and a source of DSP toxins, is discussed.

Original languageEnglish
Pages (from-to)253-264
Number of pages12
JournalHarmful Algae
Volume1
Issue number3
DOIs
Publication statusPublished - 2002 Oct
Externally publishedYes

Keywords

  • Autofluorescence
  • Dinophysis spp.
  • Mixotrophy
  • Picophytoplankton

ASJC Scopus subject areas

  • Aquatic Science
  • Plant Science

Fingerprint Dive into the research topics of 'Seasonal distribution of species of the toxic dinoflagellate genus Dinophysis in Maizuru Bay (Japan), with comments on their autofluorescence and attachment of picophytoplankton'. Together they form a unique fingerprint.

Cite this