Effect of herbicides derived from land on competition between marine diatoms and flagellates: Do the herbicides trigger the flagellates blooms?

2015 Fiscal Year Final Research Report

• Project/Area Number: 26850120
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Aquatic bioproduction science
• Research Institution: Japan Fisheries Research and Education Agency
• Principal Investigator: Onduka Toshimitsu 国立研究開発法人水産総合研究センター, その他部局等, 研究員 (00371972)
• Co-Investigator(Renkei-kenkyūsha): NAKAYAMA NATSUKO 国立研究開発法人水産総合研究センター, 瀬戸内海区水産研究所, 主任研究員 (20612675) ; ITO KATSUTOSHI 国立研究開発法人水産総合研究センター, 瀬戸内海区水産研究所, 主任研究員 (80450782) ; ITO MANA 国立研究開発法人水産総合研究センター, 瀬戸内海区水産研究所, 任期付研究員 (80450782) ; MOCHIDA KAZUHIKO 国立研究開発法人水産総合研究センター, 瀬戸内海区水産研究所, 有害物質グループ長 (00371964)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 珪藻 / 鞭毛藻 / プランクトン遷移 / 福山港

Outline of Final Research Achievements

Ten kind of herbicides were identified in environmental water in Hukuyama Port and the mouth of the Ashida River where flagellate blooms were generated in recent years. Bromobutide, cyanazine, bromacil, and pretilachlor were detected at relatively high frequency, these concentration was relatively high from June to August. Flagellate cells were identified in that same period.
The acute toxicities of these herbicides to a diatom Chaetoceros sp. and a flagellate Heterosigma akashiwo were assessed, Chaetoceros sp. was more sensitive to cyanazine, bromacil, and pretilachlor than H. akashiwo. The growth rate of the diatom was decreased with these herbicides, and the growth rate of the flagellate faster than that of the diatom in the toxicity tests. Herbicides may therefore influence generation of flagellate blooms.

Free Research Field

環境毒性学