12th International Conference on Harmful Algae

INTERNATIONAL SOCIETY FOR THE STUDY OF HARMFUL ALGAE12 th <strong>International</strong> <strong>Conference</strong> on Harmful Algae, Copenhagen, Denmark, 4-8 September 2006variations. Some bacteriaspecifically killed only one of thealgal species examined, and somekilled 2, 3, 4 or all 5 species. Thedensity of the algicidal bacteria wasin thousands / mL or higher inseawater of seaweed beds, muchmore abundant (50 times or more)than offshore. In offshore seawater,algicidal bacteria were associatedwith particles. In seaweed beds, thesame species of algicidal bacteriawere detected in particle-associatedand free-living fractions of seawaterand on the surface of seaweeds.Sequence analyses of SSU rRNAgene revealed that algicidal bacteriabelonged to marineCytophaga/Flavobacterium/Bacteroides group and α- and γ-Proteobacteria. The isolates withthe same sequences to algicidalbacteria did not always showalgicidal activities.PO.14-16Effects of alternate current ongrowth of and damage to toxicmicroalgal cellsSession: PO.14 - MitigationAyaka Ishiguro, Shin Takano,Hitoshi OgawaUniv. Tamagawa, MACHIDA-SHI TOKYO,JapanA typical pattern of the alternatecurrent of the commercial electricpower is the sine wave. However,there are various wave shapes ofthe alternating current, e.g.quadrate, triangle, saw shaped,bias, etc. Moreover, parameterssuch as voltage, current,frequency, distance betweenelectrodes, continuousness andintermittence of the current can bevaried. Although the risk for electricshock is higher with alternatecurrent than direct currentelectricity, the alternate current oflow voltages and currents are usedfor medical treatment.We observe sometime thatmicroalgae whiten in connectionwith electric leaks from submergedpumps in backyard ponds. Effectsof application patterns of thealternate current on different kindsof algae were investigated.Different effects, e.g. whitening,flaking off, cohesion and theseparation, etc. on algae wereobserved. It showed that the SSBwave of the alternate currentcauses gathering of the algae onthe electrode side. Furtherresearch on removal of the toxicsubstances from collected algae isrequired.PO.16-11Dynamics of in situ cystgermination and vegetativepopulation of Alexandriumcatenella in an embayment,central JapanSession: PO.16 – Life cyclesA Ishikawa 1 , M Hattori 1 , I Imai 21 Mie University, TSU, MIE, Japan2 Kyoto University, KYOTO, JapanSeasonal variations of in situgermination flux of cysts andabundance of vegetative cells of thetoxic dinoflagellate Alexandriumcatenella were investigated in AgoBay, central Japan, between July2003 and December 2004. The insitu germination flux (cells/m 2 /day)was measured using a new device'Plankton EmergenceTrap/Chamber (PET Chamber)' thatwe recently developed. Germinationof the cysts on the sedimentoccurred continually, ranging from52 – 1753 cells/ m 2 /day, with noseasonal trend. In contrast, the196