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 2006biological and hydrodynamicalnumerical models are beingdeveloped for A. catenella bloomsimulation in the area. In order toreconcile our observations withnumerical simulations, it appearsthat the low inoculum resulting fromcyst bank germination must remainconcentrated close to the bottom asa condition for successful bloominitiation. Less than 4 days of watercolumn stability associated with afrontal structure reduced thedispersion and supported thecohesion of the bottom cell clusters,allowing the seeding population toreach a critical density for blooming.PO.01-27Population genetic structure ofSkeletonema marinoi - a modelspecies for phytoplankton bloomdynamicsSession: PO.01 - GeneticsA GodheGöteborg University, GÖTEBORG, SwedenPhytoplankton blooms fuel coastalfood webs but can sometimes beharmful due to overwhelmingconcentrations, production of toxins,or mechanical injury. The geneticdiversity of a population is importantin determining the response tochanging environmental conditions.This diversity may also be importantfor bloom formation. We haveexamined the genetic diversity ofSkeletonema marinoi clonesisolated from Gullmar Fjord on theSwedish West Coast. This is a verycommon species in the area. Itoccurs from February to November,and reaches its highest densityduring the spring bloom in Februaryor March. More than a hundreddifferent clones were individuallyisolated from plankton samplescollected over more than one year.Allellic diversity within thepopulation was confirmed byanalyzing several microsatellite loci.Great genetic variation indicatesthat sexual reproduction is importantin the population. The high geneticdiversity of the population may be aprerequisite for its extensiveoccurrence during variable seasonalconditions. Sequencing ofconserved parts of the genome(LSU rDNA) also displayed a rangeof genetic variation, whereasmorphological features examined inthe electron microscope did notvary.PO.08-05Gyrodinium fissum: harmfulspecies or new biotechnologicalobject?Session: PO.08 - ToxicologyEvgeny B. Gol'dinSouthern Branch of the National Agrarian,SIMFEROPOL, UkraineThe dinoflagellate Gyrodiniumfissum (Gf) is poorly studied alga.Some authors regard it as red tideorganism; others as non-toxic objectof crustacean feeding; Gf biocidalactivity has not been properlystudied. We exposed lackey andbrown-tale moths, fall webworm andColorado potato beetle (Cpb) to theeffects of Gf. The leaves weretreated with a Gf culture and fed tothe insects. Gf demonstratedvarious inhibitory effects. (1)Repellent action: lackey moth larvaedid not feed and gathered in thesubstrate and jar walls. (2) Longtermdeterrent action with residualconsequences: the larval nutritionfell considerably (3.0-5.0% ofcontrol). (3) A short-term deterrentaction: brown-tale moth larvae. (4)Inhibition of growth: developmentallag of larvae of lackey moth179