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 2006mixotrophic, and that this abilitytogether with grazer resistance,may in part explain its competitiveadvantage.O.02-03Growth and survival ofDinophysis acuminata, aphototrophic marinedinoflagellate causing diarrheticshellfish poisoningSession: O.02 - Ecophysiology 1Presentation time: 11:40 - 12:00W Yih 1 , S Kim 1 , G Myung 1 , YG Kang 1 ,HS Kim 2 , MG Park 31 Kunsan National University, KUNSAN,South Korea2 Ministry of Maritime Affairs & Fisheries,KUNSAN, South Korea3 Chonnam National University, GWANGJU,South KoreaMany scientists have attempted tocultivate dinoflagellate Dinophysisspecies using various culture mediaand potential prey organismswithout any reported success. Toinvestigate the growth of Dinophysisspecies, we isolated D. acuminatacells from seawater samplescollected at Masan Bay, Korea andincubated the isolate under growthconditions (60 µmol m -2 s -1 , L/Dcycle of 14:10) supplying potentialprey species including Teleaulaxsp., a cryptophyte. Further, to knowthe effect of starvation on growth ofD. acuminata, we incubated theculture in the absence of preyorganisms under the light:dark cycleas well as continuous darkcondition, and monitored cellabundance of D. acuminata overtimes. In this study, quantitativeimportance of potential preyorganism for the growth andsurvival of D. acuminata will bediscussed.O.02-04Broad predator-prey relationshipamong the mixotrophic red-tidedinoflagellatesSession: O.02 - Ecophysiology 1Presentation time: 12:00 - 12:20HJ Jeong 1 , YD Yoo 1 , NS Kang 1 , JYSong 2 , TH Kim 2 , WH Yih 2 , JY Park 11 Seoul National University, SEOUL, SouthKorea2 Kunsan National University, KUNSAN,South KoreaWe investigated predator-preyrelationship among phototrophicred-tide dinoflagellates. There arebroad predator and preyrelationships among red-tidedinoflagellates (Akashiwosanguinea, Alexandrium tamarense,Amphidinium carterae,Gymnodinium catenatum, G.impudicum, Heterocapsa triquetra,Lingulodinium polyedrum,Prorocentrum donghaiense, P.micans, P. minimum, P. triestinum,and Scrippsiella trochoidea).Akashiwo sanguinea and L.polyedrum were able to ingest thesmall red-tide dinoflagellates P.minimum, H. triquetra, S.trochoidea, and A. tamarense.Maximum specific growth rates of L.polyedrum on P. minimum and S.trochoidea were 0.254 and 0.303 d -1 , respectively, under a 14:10 hlight-dark cycle of 50 µmol m -2 s -1 ,while their growth rates withoutadded prey were 0.157 and 0.182 d -1 , respectively. Maximum ingestionrates of L. polyedrum on S.trochoidea and P. minimum were0.20-0.36 ngC grazer -1 d -1 . Thecalculated grazing coefficients of L.polyedrum on small Prorocentrumspp. and S. trochoidea were up to0.026 and 0.011 h -1 , respectively.The results of the present studysuggest that L. polyedrumsometimes have a potentially30