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 2006(42 600 cells of Dinophysis spp/L),[AO] was 25,4 pg/cell, while forDinophysis acuta, the [DTX2] was25 pg of equivalent AO/cell.than 32 psu. The characteristicsand the distribution of thispotentially toxic genus arediscussed.PO.13-64A post-tsunami study on thediversity of dinoflagellates in thecoastal area of Phang-ngaProvince, ThailandSession: PO.13 - Regional eventsN Mongkonsangsuree, C Songroop, APiumsomboon, N PhapavasitChulalongkorn University, BANGKOK,ThailandAn assessment of tsunami damageon the mangrove and coastalecosystem of Nam Khem Village,Phang-nga province, southernThailand was carried out in October2005. The area was damaged bythe tsunami event in December2004. The water intrusion intomangrove creeks and thedestruction of mangrove trees bythe over-washed wave causedserious problems for both theecosystem diversity and function.Thus, a study on the diversity anddistribution of phytoplankton andbenthic microalgae was conductedto assess the long-term impact ofthe tsunami. Duplicate watersamples were collected fromsubsurface and bottom depths at 7stations located along the waterchannel between the main land andKho-kao Island and in the mangrovecreeks. A total of 15 genera ofdinoflagellates were found in thearea with Protoperidinium, Ceratiumand Prorocentrum as the mostabundant genera. Dinoflagellatecysts were also observed. A highdensity of Prorocentrum, more than200 cells/l, was recorded in the midchanneland the adjacent mangrovecreek where the salinity was higherPO.01-07Molecular characterization andmorphological variability ofseven strains of thedinoflagellate ProrocentrumminimumSession: PO.01 - GeneticsM Monti, B CatalettoOGS, TRIESTE, ItalyThe class Dinophyceae has beenthe subject of several molecularstudies that have clarified thephylogenetic position ofdinoflagellates with respect to otherprotists and have helped toestablish new genera. However,within the same dinoflagellatespecies, morphological features cansometimes vary in response tochanging environmental conditionsor physiological states.Prorocentrum minimum has been asubject of interest to taxonomistsbecause of its highly variablecellular morphology. This has givenrise to a debate about whether thedifferent shapes represent separatespecies or only one variable taxon.The morphological diversity ofseven strains of P. minimum fromdifferent geographical areas wasinvestigated using a range of cellcharacters, and intraindividualgenetic diversity was assessed bysequencing the internal transcribedspacer regions (ITS1 – ITS2). Threestrains originated from the AdriaticSea, two from the Baltic Sea, onefrom the Gulf of Finland and onefrom Chesapeake Bay (USA). Allstrains were kept under controlledconditions, at their original salinities.From the morphological and243