title: In situdynamics of cyst and vegetative cell populations of the toxic dinoflagellateAlexandrium catenellain Ago Bay, central Japan.
abstract: Temporal changes in thein situgermination flux of cysts and the abundance of vegetative cells of the toxic dinoflagellateAlexandrium catenellawere investigated in Ago Bay, central Japan from July 2003 to December 2004. Thein situgermination flux (cells m-2day-1) was measured using 'plankton emergence trap/chambers (PET chambers)'. Germination of the cysts in the sediments occurred continuously during the study, ranging from 52 to 1753 cells m-2day-1, with no temporal trend. This germination pattern appeared to be promoted by a short mandatory dormancy period for newly formed cysts coupled with a broad temperature window for germination. For the vegetative populations, high abundances (>105cells m-2) were recorded in the water column from spring to summer and from autumn to early winter. The size of the vegetative populations did not correlate with the cyst germination flux but rather larger vegetative populations were often observed when the water temperature was around 20°C, indicating that bloom development was mainly regulated by the temperature. Nonetheless, the continuous germination pattern ofA. catenellais advantageous enabling the germinated cells to immediately exploit favorable bloom conditions.
authors.affiliation: Graduate School of Bioresources , MIE University , 1577 Kurima-Machiya-Cho, TSU, MIE 514-8507 , Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ishikawa
authors.affiliation: Graduate School of Bioresources , MIE University , 1577 Kurima-Machiya-Cho, TSU, MIE 514-8507 , Japan.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Hattori
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture , Kyoto University , Oiwake-Cho, Kitashirakawa, Sakyo-Ku, Kyoto 606-8502 , Japan.
authors.forename: Ken-Ichiro
authors.initials: KI
authors.lastname: Ishii
authors.affiliation: Biology Department , Woods Hole Oceanographic Institution , Woods Hole, MA 02543-1049 , USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Kulis
authors.affiliation: Biology Department , Woods Hole Oceanographic Institution , Woods Hole, MA 02543-1049 , USA.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Anderson
authors.affiliation: Graduate School of Fisheries Sciences , Hokkaido University , Minato-Cho, Hakodate, Hokkaido 041-8611 , Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Imai
keywords: Alexandrium catenella; bloom formation; cyst; in situ germination; population dynamics