Feeding and Growth Characteristics of a Diatom-Feeding Flagellate Isolated from the Bottom Sediment of Onagawa Bay, Northeastern Japan  

作　　者：Hiromasa Ohno Yoshinari Endo Waka Sato-Okoshi Goh Nishitani 

机构地区：[1]Graduate School of Agricultural Science, Tohoku University, Sendai, Japan

出　　处：《Open Journal of Marine Science》2013年第2期9-14,共6页海洋科学期刊（英文）

摘　　要：In recent years, several marine heterotrophic nanoflagellates have been reported to feed on diatoms much larger than themselves. However, very little is known about the grazer-prey relationships between heterotrophic nanoflagellates and diatoms in aquatic ecosystems. A diatom-feeding flagellate was discovered in the bottom sediment of OnagawaBay. It fed and proliferated on diatoms, especially Skeletonema costatum sensu lato. This study determined growth and ingestion rates of the flagellate on Skeletonema costatum s.l. under laboratory conditons. Its grazing pressure on the sinking flux of S. costatum s.l. was calculated by combining field data. Specific growth rate of the flagellate increased with increasing prey concentration. The maximum specific growth rate was 0.79 d–1 and maximum ingestion rate of the flagellate was 0.66 ng·C·grazer–1·d–1. Calculated grazing pressure of the flagellate on S. costatum s.l. flux was up to 25.6%. The results imply that the flagellate has a considerable grazing impact on S. costatum s.l. flux at least in a restricted season of the year. Therefore, the present study suggests that this benthic flagellate plays an important role in pelagic-benthic coupling inOnagawaBay.In recent years, several marine heterotrophic nanoflagellates have been reported to feed on diatoms much larger than themselves. However, very little is known about the grazer-prey relationships between heterotrophic nanoflagellates and diatoms in aquatic ecosystems. A diatom-feeding flagellate was discovered in the bottom sediment of OnagawaBay. It fed and proliferated on diatoms, especially Skeletonema costatum sensu lato. This study determined growth and ingestion rates of the flagellate on Skeletonema costatum s.l. under laboratory conditons. Its grazing pressure on the sinking flux of S. costatum s.l. was calculated by combining field data. Specific growth rate of the flagellate increased with increasing prey concentration. The maximum specific growth rate was 0.79 d–1 and maximum ingestion rate of the flagellate was 0.66 ng·C·grazer–1·d–1. Calculated grazing pressure of the flagellate on S. costatum s.l. flux was up to 25.6%. The results imply that the flagellate has a considerable grazing impact on S. costatum s.l. flux at least in a restricted season of the year. Therefore, the present study suggests that this benthic flagellate plays an important role in pelagic-benthic coupling inOnagawaBay.

关 键 词：Diatom-Feeding HETEROTROPHIC Nanoflagellate Growth GRAZING Impact Pelagic-Benthic Coupling 

分 类 号：R73[医药卫生—肿瘤]