Inhibiting effects of benthic diatoms on the harmful dinoflagellate Karenia mikimotoi performing diurnal vertical migration

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K14960
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Aquatic bioproduction science
• Research Institution: Hokkaido University
• Principal Investigator: Imai Ichiro 北海道大学, 水産科学研究院, 特任教授 (80271013)
• Research Collaborator: Miyamura Kazuyoshi ; Iwano Hideki
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 赤潮 / 底生珪藻 / 羽状目珪藻 / 中心目珪藻 / 珪藻休眠期細胞 / Karenia mikimotoi / 日周鉛直移動 / 増殖阻害

Outline of Final Research Achievements

The harmful dinoflagellate Karenia mikimotoi performs diurnal vertical migration reaching deeper than 20m deep at night. When K. mikimotoi reach the sea bottom, dwelling pennate diatoms probably give various adverse effects on K. mikimotoi. The densities of penante diatoms and resting stage cells of centric diatoms were detected as many as 104 ~ 106 cells per gram wet sediments. The existence of pennate diatoms with densities morathan 0.1 million per gram wet sediment inhibited the diurnal vertical migration and growth of K. mikimotoi. Newly established pure strain of Nitzschia sp.1 entirely killed K. mikimotoi through co-culture experiment. Freshly collected sediments were also inhibiting to K. mikimotoi, and the grazer ciliate Pleuronema sp. was newly isolated as predator on K. mikimotoi. Obtained results showed that the pennate diatoms dwelling sea bottom inhibited the growth of K. mikimotoi and ciliates probably also kill K. mikimotoi at sea bottom in the shallow area.

Free Research Field

有害有毒プランクトン