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Harmful algal blooms: mechanisms, monitoring, and prevention in a rapidly changing world
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Pseudocryptic speciation in Protoceratium reticulatum (Dinophyceae) and its relationship with biogeography and physiology
P-B1-11
Na Wang* , Third Institute of Oceanography, SOA, Xiamen 361005, China
Bernd Krock, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany
Kenneth Neil Mertens, Ifremer, LER BO, Station de Biologie Marine, Place de la Croix, BP40537, F-29185 Concarneau CEDEX, France
Zhaohe Luo, Third Institute of Oceanography, SOA, Xiamen 361005, China
Urban Tillmann, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany
Haifeng Gu, Third Institute of Oceanography, SOA, Xiamen 361005, China
Presenter Email: wangna@tio.org.cn |
| Protoceratium reticulatum is a marine toxic dinoflagellate widely distributed around the world. However, its growth and toxin-producing characteristics differ markedly among different origin of strains. In this study, a total of 38 strains and 12 cysts of P. reticulatum were obtained from several climatic zones including British Columbia, Mediterranean Sea, New Zealand, Chile, Chukchi Sea, Greenland, Norway, Yellow Sea, East China Sea and South China Sea. The morphology of some strains was examined with light microscopy and scanning electron microscopy. Large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS)sequences of all the strains and cysts were obtained. Molecular phylogeny based on ITS rDNA sequences identified three distinct ribotypes (referred as ribotypes A, B and C) within P. reticulatum. Ribotype A was only found in cold waters and ribotype B was found in warm waters. Sympatric occurrence of ribotypes A and B was observed in Yellow Sea. Growth experiments were carried out on one stain of ribotype A and one strain of ribotype B from Yellow Sea; P. reticulatum ribotype B exhibited the highest growth rate at 20 degrees Celsius and 25 degrees Celsius (0.52 and 0.50 divisions/day), but the highest growth rate of P. reticulatum ribotype A occurred at 20 degrees Celsius and 15 degrees Celsius (0.26 and 0.25 divisions/day); P. reticulatum ribotype A could not survive at 25 degrees Celsius. Yessotoxins(YTXs) profiles of 13 cultured P. reticulatum were analyzed using LC-MS/MS. These results demonstrated that all P. reticulatum ribotypes could produce high level YTXs . Our results support that pseudocryptic speciation occurred in P. reticulatum which is related with their ecophysiological differentiation. |
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