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 20061 INTECMAR, VILAGARCÍA DE AROUSA,Spain2 Centro de Investigacions Mariñas,VILANOVA DE AROUSA, SpainIn order to assess the variability inboth content and profile of lipophilictoxins per Dinophysis acuta cell, twotoxic outbreaks were studied, inwhich this toxic species was thedominant one. In the first bloom(2001) water samples werecollected by net tow (from 0 to 15meters) in three nearby stations, on3 October. In the second one,(autumn 2005), plankton sampleswere collected weekly at threedepth intervals (0-5, 5-10 and 10-15meters) using a hose. The toxincontent of the plankton sampleswas analysed, in the first case byHPLC-FD, and in the second by LC-MS, and in both casesphytoplankton was quantified in ainverted microscope. The toxincontent per D. acuta cell wasindependent of cell concentrationand ranged from 0.20 to 10.8pg·cell -1 , without significantdifferences between the twoepisodes. In the samples from2001, OA, its conjugated forms andpectenotoxins were detected, with aslight predominance of OAconjugatedforms. During 2005, OA,DTX2 and the conjugated forms ofboth toxins were found in veryvariable proportions, even betweendifferent depths during the sameday, but with a slight predominanceof free OA.PO.13-71Foam events due to aPhaeocystis bloom along theCatalan coast (NWMediterranean)Session: PO.13 - Regional eventsL Arin, N Sampedro, M Segura, K vanLenning, A Calbet, J Guillén, A Reñe, DBlasco, J CampInstitut de Ciències del Mar, BARCELONA,SpainMarine haptophytes of the genusPhaeocystis may produce nearlymonospecific blooms in manynutrient-rich areas. Dense bloomsof Phaeocystis colonies in coastalzones are frequently associatedwith extensive masses of foam,causing problems for local fishingactivities and tourist industries. InMarch 2006, a Phaeocystis bloomoccurred along the Catalan coast(NE Spain). The bloom wasassociated with foam formation andextended several kilometres incoastal waters. Based on theobserved morphology of thecolonies, the responsible specieswas identified as P. globosa. Thebloom was not monospecific asdiatoms were also abundant (mostlymembers of the generaRhizosolenia, Chaetoceros,Pseudo-nitzschia andBacteriastrum). Phaeocystis haspreviously been recorded along theCatalan coast, but not at such highdensities. On this occasion, theabundance of cells was highenough to produce visible amountsof foam that could, for the first time,be recorded by ARGUS videocameras installed in the area.PO.06-11Gymnodinium catenatumpreference for and growth onnitrate, ammonium and ureaSession: PO.06 - Population dynamicsPA Armstrong 1 , PA Thompson 2 , CJBolch 3 , SIE Blackburn 21 University of Tasmania, Aquafin CRC,HOBART, Australia2 CSIRO, HOBART, Australia128