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 2006early spring of 2005 obviouslyinfluenced the succession pattern ofphytoplankton, inducing the unusualproliferation of certain algae such asK. mikimotoi.PO.01-12Genetic diversity within BalticSea populations of nodularinproducingNodularia spumigenaand non-toxic NodulariaharveyanaSession: PO.01 - GeneticsB Luckas, T Krueger, S Hiller, ROelmuellerUniversity Jena, JENA, GermanyThe genus Nodularia was recentlydivided into seven species. Fourspecies (Nodularia spumigena, N.baltica, N. litorea, and N. crassa)are planktic with the capability toproduce gas vesicles. Threespecies (N. harveyana, N.sphaerocarpa, and N. willei) lackgas vesicles and grow in benthic,periphytic, or soil habitats. Methodsinvolving the whole genome and16SrRNA sequences have indicatedthe close overall relatedness ofNodularia strains and alsodistinguished the nodularinproducingstrains from the non-toxicones [1].Recently, Nodularia spumigena(Huebel 1988/306) and Nodulariaharveyana (Huebel 1983/300) fromthe Baltic Sea were tested forproduction of nodularin, and only N.spumigena proved to be toxic.Therefore, the gene clusters of bothspecies were analysed.Characteristic differences wereobserved. Southern analysesdemonstrated that the cluster of N.harveyana lacks DNA sequencesencoding the subunits NdaE/F.[1] M.J. Laamanen, M.F. Gugger,J.M. Lehtimaki, K. Haukka, K.Sivonen. 2001. Appl. Environ.Microbiol. 67:4638-4647.PO.13-92Cyanobacteria blooms - apossible cause of mass mortalityof Lesser Flamingos in LakeManyara and Lake Big Momela,TanzaniaSession: PO.13 – Regional eventsCharles Lugomela, Harish B. Pratap,Yunus D. MgayaUniversity of of Dar es Salaam, DAR ESSALAAM, TanzaniaLimnological studies wereconducted in three alkaline lakes(Lake Big Momela, Manyara andEmbagai) with the aim ofinvestigating the cause of massmortality of the Lesser Flamingos inLake Manyara and Lake BigMomela during July–August 2004.High concentrations, up to 150million filaments per liter of thepotentially toxic planktoniccyanobacterium Arthrospirafusiformis were found in surfacescum of Lake Big Momela whereLesser Flamingos were dying at arate of between 15 and 50individuals per day during the studyperiod. Gut content analysesindicated that A. fusiformis was themain food item in moribundflamingos. Mouse bioassaysuggested that the crude microalgalextract dominated by A. fusiformiswas toxic with all mice close todeath becoming lethargic, with lossof balance, uncoordinatedmovements, intermittent tremors,dyspnoea with gasping followed byrespiratory arrest. This observationgives circumstantial evidence thatA. fusiformis at such highconcentrations was toxic to the228