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 2006Presentation time: 12:40 - 13:00Mingjiang Zhou 1 , Mingyuan Zhu 2 ,Yunfeng Wang 1 , Dedi Zhu 3 , SonghuiLv 4 , Douding Lu 3 , Xiaoyong Shi 5 ,Chuansong Zhang 51 Institute of Oceanology, CAS, QINGDAO,China2 First Institute of Oceanography, QINGDAO266061, China3 Second Institute of Oceanography, SOA,HANGZHOU 310012, China4 Jinan University, GUANGZHOU 510632,China5 Ocean University, QINGDAO 266003,ChinaIn 2005, CEOHAB (Ecology andOceanography of Harmful AlgalBlooms in China) carried out 5cruises to further understand themechanisms of large scaleProrocentrum blooms along eastChinese coast, near Changjiangriver estuary and Zhejiang coast.The blooms re-occurred for severalyears at nearly the same time. Itsoccurrence was delayed in 2005,following a succession of bloomspecies, from Skeletonema toKarenia and then Prorocentrum.Preliminary clues were obtained toexplain this phenomenon. First,physical oceanographic datashowed that significant lowtemperatures of the seawater mayhave played an important role. Thetemperature of sea water at the endof March was about three degreeslower compared with 2004 and wasnot favourable for Prorocentrum togrow. Secondly, more nutrient inputfrom excessive runoff of Changjiangriver during winter might also play arole. And thirdly, different adaptivestrategies caused diatoms tobecome dominant in the earlyspring, and the dinoflagellates later,so that Prorocentrum was delayed.Short-term climate changeapparently could have a significantimpact on the outbreak andsuccession of large-scale HABsalong the east Chinese coastthrough alterations of environmentalconditions.PL.08The physical oceanographiccontrol of harmful algal bloomsSession: PL..08 - Plenary VIII – Ecologyand OceanographyPresentation time: 14:15 - 14:50Robin RaineThe Martin Ryan Institute, NationalUniversity of Ireland, GALWAY, IrelandMany HABs impacting onaquaculture regions or other sitesof amenity value arise becausethey are transported to the site.This occurs with local currents orelse with water whose circulation issubjected to shifts in forcingvariables such as the wind. Asound knowledge of coastal andnear shelf physical oceanographicprocesses is therefore of immenseimportance if we are to predict HABevents with confidence. Theeffects of coastal currents,upwelling, and estuarineentrainment in transporting bloomshave been acknowledged for sometime. More recently, the influencesof coastal and tidal fronts, windforced water exchanges in bays,coastal jets and gyres have beenstudied in relation to HABs. Manycoastal bays also have residentpopulations of HAB species. Thissituation arises not only due to adormant sessile stage in the lifecycle, but also because thebalance between growth andphysical dilution of the bay favoursa bloom.This paper reviews physicaloceanographic processes withinthe context of HAB events usingIrish coastal waters as an example.Data is also presented which78