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 2006In 1968 the first instance of PSPtoxicity in the UK was documented,linked to Alexandrium tamarense.Alexandrium species are a regularfeature of the early summerphytoplankton assemblage invarious parts of the country andPSTs are regularly recorded inshellfish. Over the years a range ofstudies on Alexandrium have beencarried out in various parts of thecountry and further Alexandriumspecies (A. minutum and A.ostenfeldii) have been detected.The advent of molecular studiesand the identification of tworibotypes for Alexandriumtamarense (North American andWestern European) that occur in theUK, have further complicated thispicture. The overlap in occurrenceof these ribotypes is particularlyinteresting from an ecologicalstandpoint and as part of the EUfunded SEEDS project we areinvestigating the occurrence andmating capability of Alexandriumtamarense strains around the coastof the British Isles. In thispresentation we will bring togetherall that is known (from disparatesources) of the occurrence ofAlexandrium species in Britishcoastal waters and highlight areaswhich merit more detailedinvestigation.PO.08-17Production of spirolides in singlecells of Alexandrium ostenfeldiithroughout the diurnal cycleSession: PO.08 - ToxicologyNI Lewis, CM Garnett, CT Leggiadro,CM Rafuse, MA QuilliamNational Research Council, HALIFAX, NS,CanadaThe production of toxic metabolitesby dinoflagellates is known to beaffected by both environmental andgenetic factors. Changes in toxincontent during the cell cycle havebeen observed in several toxicspecies including Alexandrium spp.In this study, a micro-column LC-MS system was used to quantifytoxin concentration within a singlecell over the diurnal cycle, allowingthe accurate determination ofchanges in spirolide quota of singlecells of AOSH1, an isolate ofAlexandrium ostenfeldii. Digitalimage analysis was used todetermine the volume of individualcells, which facilitated accuratecalculation of des methyl-Cconcentration following analysis. Inaddition, changes in mean cell sizein the culture were monitored usinga Coulter Multisizer. A distinctadvantage of this method was thatthe toxin profile and concentrationcould be determined for individualcells undergoing division. Thesemethods allowed furtherexamination of differences in thebio-volume of live and preserved(Lugol’s) cells.PO.10-25Nitrogen uptake rates bysuccessive dinoflagellate bloomsin the East China Sea, 2005, andvariation with nitrogen andphosphorus statusSession: PO.10 - Ecophysiology &autecologyJ Li 1 , PM Glibert 1 , S Lu 2 , D Lu 3 , X Shi 4 ,C Zhang 41 Horn Point Laboratory, UMCES,CAMBRIDGE, MD, United States ofAmerica2 Institute of Hydrobiology, Jinan Univ.,GUANGZHOU, China3 Second Institute of Oceanography, SOA,HANGZHOU, China4 Ocean University of China, QINGDAO,China218