12th International Conference on Harmful Algae

More documents

Recommendations

Info

INTERNATIONAL SOCIETY FOR THE STUDY OF HARMFUL ALGAE12 th <strong>International</strong> <strong>Conference</strong> on Harmful Algae, Copenhagen, Denmark, 4-8 September 2006Gambierdiscus toxicus were grownin N- (nitrate, ammonium, freeamino acids, urea, or putrescine) orP-limited (phosphate, ß-glycerophosphate, or nucleotides)xenic batch cultures. Growth ratesranged from 0.11- 0.18 d -1 excepton urea (no growth). Cellular N andP pools were uncoupled fromconditions in the water and celldivision continued after the limitingnutrient was below detectable limits.N:P varied from 3-34 (1651) and 2-37 (strain 1655) with no relationshipbetween cellular N:P and totaltoxicity. Strain 1655 was roughlyfive-fold more toxic than strain 1651.The N source had no effect ontoxicity in either strain. The Psource had no effect on toxicity instrain 1651, but strain 1655 cellsgrown on ß-glycerophosphate weremore toxic. Stationary phase cellswere more toxic than exponentialphase cells in both strains underboth N- and P-limitation. In P-limited semi-continuous cultures,the toxicity of strain 1655 decreased(43.7-79.3 fg C-Ctx1Eq cell -1 ) as thegrowth rate increased (0.02-0.15 d -1 ). Toxicity differences were afunction of growth phase (batchculture) or growth rate (semicontinuousculture). Nutrient sourceand type of nutrient limitation havinglittle to no effect.PO.13-58Involvement of cyanobacteria inthe tropical ecotoxicologicalphenomenon of ciguatera fishpoisoningSession: PO.13 - Regional eventsD Laurent, AS Kerbrat, I de Fremicourt,T Darius, M Chinain, S PauillacIRD, NOUMEA, New CaledoniaDuring 2005, a cyanobacterialproliferation (Hydrocoleumlyngbyaceum) was found to inducea severe ciguatera outbreak in Lifou(Loyalty Islands, New Caledonia).Lipid-soluble extracts ofcyanobacteria and giant clams werefound to contain CTX-likecompounds, as assessed byneuroblastoma cell bioassays andcompetitive membrane-bindingassay using tritiated brevetoxin-3.According to the mouse bioassay,water-soluble extracts of bothsamples appear to contain the wellknownalkaloid neurotoxinsproduced by cyanobacteria andresponsible for Paralytic ShellfishPoisoning (PSP).This is the first demonstration ofsimultaneous occurrence of PSPtoxins and CTX-like toxins inextracts of marine cyanobacteria.The chemical identification of thesetoxins is currently underway byliquid chromatography coupled withmass spectrometry (LC/MS).Although long-term observations willbe necessary to decipher the trendsin dinoflagellate and cyanobacteriapopulations as well as thefavourable environmentalparameters, the new findingsrequire that CFP risk assessmentprograms must now includemonitoring of cyanobacteria besidesthe usual screening fordinoflagellates. In the perspective ofglobal warming, such events wouldprobably arise more frequently.PO.11-02Effect of bicarbonate addition onallelopathy in OscillatoriaagardhiiSession: PO.11 – AllelopathyLA Lawton 1 , GA Akin-Oriola 2 ,1 The Robert Gordon University,ABERDEEN, United Kingdom2 Lagos State University, LAGOS, Nigeria215
INTERNATIONAL SOCIETY FOR THE STUDY OF HARMFUL ALGAE12 th <strong>International</strong> <strong>Conference</strong> on Harmful Algae, Copenhagen, Denmark, 4-8 September 2006Phytoplankton species competewith each other for limitingresources especially nutrients. Thishas led to the evolution of differentstrategies ensuring their competitiveadvantage over other species inresource utilization. An example ofsuch a strategy is allelopathy – therelease of organic compounds byplants into the medium, whichaffects competiting species. Thisstudy investigates the effect ofbicarbonate-enriched spent mediaof non-toxic O. agardhii CYA 29 ongrowth and toxin concentration in M.aeruginosa PCC 7820.Bioassays were carried out in BG11 media to which were addedeither i) 15mM of bicarbonate ii) 0.1% (v/v) spent medium of O. agardhiior iii) 15mM bicarbonate and 0.1 %(v/v) spent medium of O. agardhii.The cultures were incubated at 25°C and sampled for biomass andtoxin concentration.A statistical analysis using Tukey’shonestly significant difference testshowed that after 3 weeks, biomassand total microcystin concentrationwere higher in cultures with spentmedia than those with bicarbonateand spent media. In contrast,microcystin concentrationdecreased six-fold in cultures withbicarbonate.Conclusion: addition of bicarbonateand/or spent media of O. agardhiihas a significant impact on growthand toxin production in M.aeruginosa.PO.11-14Epilithics biofilms: effect ofallelopathic compound onstructure and algal productionSession: PO.11 - AllelopathyJ Leflaive, L Ten-HageUniversité Paul Sabatier, TOULOUSE,FranceProduction of allelochemicals maybe considered as a competitor- andpredator-exclusion process. Epilithicbiofilms are benthic microbialaggregates formed by anassociation of autotrophs andheterotrophs, prokaryotes as well aseukaryotes. With the relativelycohesive organization ofmicroorganisms, theseagglomerates are quite auspiciousfor allelopathic interactions. The aimof this study is to show the effects ofthe presence of an allechemicalproducingstrain on biofilm structureand production. The experimentalset-up was based on artificialbiofilms, grown in microcosms andcomposed of a limited number ofalgal species (cyanobacteria anddiatoms, isolated from naturalbiofilms). Non-destructivetechniques of biofilm investigationswere used in order to elucidate bothspatial structure and functioning(laser-scanning confocalmicroscopy, microelectrodes). Toeliminate the effects of competition,extracts containing cyanobacterin,an allelopathic compound producedby the cyanobacteria Scytonemahofmannii, were added to thebiofilms. In a more general context,epilithic biofilm is an example ofcomplex integrated system whosedynamic functioning involves manysignalisation and regulationnetworks. This study aim tounderstand how allelopathicinteraction can modify biofilmfunctioning and structure.PO.06-13Effects of varying salinity andN:P ratios on the growth andtoxicity of Karenia brevisSession: PO.06 - Population dynamicsDK Lekan216
Page 1 and 2:
INTERNATIONAL SOCIETYFOR THE STUDY
Page 3 and 4:
Dear participantWelcome to Denmark
Page 5 and 6:
INTERNATIONAL SOCIETY FOR THE STUDY
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166: INTERNATIONAL SOCIETY FOR THE STUDY
Page 215: INTERNATIONAL SOCIETY FOR THE STUDY
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
Page 321 and 322:
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
Page 329 and 330:
Page 331 and 332:
Page 333 and 334:
Page 335 and 336:
Page 337 and 338:
Page 339 and 340:
Page 341 and 342:
Page 343 and 344:
Page 345 and 346:
Page 347 and 348:
Page 349 and 350:
Page 351 and 352:
Page 353 and 354:
Page 355 and 356:
Page 357 and 358:
Page 359 and 360:
Page 361 and 362:
Page 363 and 364:
Page 365 and 366:
Page 367 and 368:
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Page 389 and 390:
Page 391 and 392:
Page 393 and 394:
Page 395 and 396:
Page 397 and 398:
Page 399 and 400:
Page 401 and 402:
Page 403 and 404:
show all

12th International Conference on Harmful Algae

Create successful ePaper yourself

Delete template?

Save as template?