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 2006mg/dm 3 ) have been associated withincreased concentrations ofammonia nitrogen (2.5–9.2mg/dcm 3 ), and organic phosphorus(0.97–3.07 mg/dcm 3 ), representinga polytrophic status(Burchardt 1987). Aphanizomenonflos-aquae surface blooms in thelake were associated withincreasing numbers and size of gasvacuoles in their trichomes, andoccurred during the initial phase ofthe bloom and associated withhigher iron concentrations (e.g. 0.18mg/l). Vegetative cell division of A.flos-aquae and production ofheterocysts and akinetes occurredwhen phosphate levels exceeded0.3 mg/l (Burchardt 1987). The lakewater analysis in 1998 included theconcentration of algal biomass,nutrients, N:P coefficient, and iron(Burchardt, Kokocinski, Owsianny2000). The combinations of thedifferent mineral forms of iron tomineral forms of nitrogen andphosphate were found to beresponsible for inhibitingdevelopment of Aphanizomenonflos-aquae as well as for thedevelopment of akinetes fromsediments. Avaibility of the mineralform of iron (III), involved in thephotosynthesis process, was foundto be a stimulating factor forincreased abundance ofAphanizomenon flos-aquae inSwietokrzyskie Lake.PO.01-24Phytoplankton assemblages inballast water of U.S. militaryships considering port of origin,voyage time and ocean exchangepracticesSession: PO.01 - GeneticsJM Burkholder 1 , GM Hallegraeff 2 , GMelia 3 , A Cohen 4 , D Oldach 5 , HBowers 5 , MW Parrow 6 , MA Mallin 71 Center for Applied Aquatic Ecology,RALEIGH, United States of America2 School of Plant Science, U. of Tasmania,HOBART, Australia3 Depart. Environ. and Natural Resources,RALEIGH, United States of America4 San Francisco Estuary Institute,OAKLAND, United States of America5 Institute of Human Virology, U. of MD,BALTIMORE, United States of America6 Department of Biology, UNC Charlotte,CHARLOTTE, United States of America7 Center for Marine Sci., UNC Wilmington,WILMINGTON, United States of AmericaEnvironmental conditions andphytoplankton assemblages werecharacterized in ballast water from62 ballast tanks aboard 28 shipsoperated by the U.S. Military SealiftCommand and the MaritimeAdministration, sampled at 9 portson the U.S. West Coast and 4 portson the U.S. East Coast. The ballasttank waters had been held for 2-176days, and 90% of the tanks hadundergone ballast exchange withopen ocean waters. One hundredphytoplankton species wereidentified including 22 potentiallyharmful taxa. Assemblages weredominated by chain-formingdiatoms and dinoflagellates, andviable organisms comprised abouthalf of the total cells. Phytoplanktonabundances were unrelated to themeasured physical/chemicalparameters, except for a positiverelationship between centric diatomabundance and nitrateconcentrations. Abundancegenerally was higher in tanks withcoastal water sources anddecreased with water age. Tankswith ballast water more than 33days old did not produce culturablephytoplankton. Abundances ofviable phytoplankton with maximumdimension > 50 µm exceededproposed <strong>International</strong> MaritimeOrganization standards in 47% ofthe ballast tanks sampled. The datasuggest that further treatment142