多田 邦尚

領域名 環境生態機能学

教員氏名  多田 邦尚 

研究分野 化学生物海洋学

研究キーワード:沿岸海洋,栄養塩,植物プランクトン, 瀬戸内海, 堆積物

最近の研究課題

1.瀬戸内海の栄養塩異変の原因究明と未来

 瀬戸内海は高度経済成長期に富栄養化が著しく進行し,赤潮が多発した. 1973年には瀬戸内法が施行され,その後,窒素やリンの排水総量規制もなされるなど,水質を中心に環境改善の努力が続けられてきた. その結果,赤潮の発生件数は最頻時の1/3に減少するなど水質は改善されたが, 近年はイワシ類やアサリ等の漁獲量の減少,ノリの色落ちなど,「きれいすぎる海」が問題になっている. 今後の栄養塩管理を如何に行うべきか?NやPの河川からの流入、および海水中から海底堆積物までのNやPの循環を調べつつ研究を進めている。

2.夜光虫の生態

 瀬戸内海で発生する赤潮のうち夜光虫の赤潮がもっとも多い。また、夜光虫は赤潮を形成していない時でも、その生物量は無視できないほど大きい。夜光虫の生物量の変化と沿岸海域の物質循環に及ぼす影響について調べている。

代表的な研究業績

Tada, K., et al. (1998): Standing stocks and production rates of phytoplankton and abundance of bacteria in the Seto Inland  Sea, Japan.  Journal of Oceanography  54, 285 – 295.

Tada, K. et al. (2000): Carbon and nitrogen content of Noctiluca scintillans in the Seto Inland Sea, Japan.  Journal of   Plankton Research  22, 1203 – 1211.Tada, K., et al. (2004): Seasonal variation in the abundance of  Noctiluca scintillans in the Seto Inland Sea, Japan.  Plankton  Biology and Ecology,  51, 7-14.

Tada, K. et al. (2009) : Diatoms Grow Faster Using Ammonium in Rapidly Flushed Eutrophic Dokai Bay, Japan.. Journal of Oceanography, 65, 885 – 891.Nishikawa, T. et al. (2010) : Nutrient and Phytoplankton Dynamics in Harima-Nada, Eastern Seto Inland Sea, Japan During a 35 Year Period from 1973 to 2007. Estuaries and Coast, 33, 417 – 427.

Asahi, T. et al. (2014): Horizontal distribution of particulate matter and its characterization using phosphorous as an indicator in surface coastal water, Harima-Nada, the Seto Inland Sea, Japan, Journal of Oceanography, 70, 277 – 287.

多田ら (2014):瀬戸内海東部海域の栄養塩異変とその影響, 沿岸海洋研究,52,39-47.

Tada, K.,et al. (2017).: Negligible effect of the benthic fauna on measuring the nutrient  upward fluxes from coastal           sediments, Journal of Oceanography, 73, 397-402 .

Research Area: Environmental & Ecological Science 
Research Specialization:  Chemical and Biological Oceanography 
Name: TADA, Kuninao

Keywords:Coastal water,Nutrient, Phytoplasnkton,Seto Inland Sea,Sediment

Recent Research

1. Nutrient decrease in the Seto Inland Sea and nutrient control in the future

      During high economic growth of the 1960s and thereafter, the Seto Inland Sea, Japan was heavily eutrophicated, and red tide occurred often. To resolve the situation, the Law for Conservation of Environment of Seto Inland Sea was enacted in 1973 to regulate industrial effluent and urban wastewater. With the enactment of this law, the annual occurrence of red tides in the Seto Inland Sea decreased from 300 to 100.However, with changes in nutrient levels, the fisheries yields of species such as sardine and short-neck clam were affected negatively.Also, seaweed Nori culture was heavily damaged. How can we control the nutrient level? We investigate the nitrogen and phosphorous cycle in the coastal environment.We are studying about N and P loading from the land, and the behavior of N and P in the seawater and bottom sediment.

2. The ecology of Noctilucascintillans

      Noctiluca scintillans red tide is the most frequent in all red tide outbreaks in the Seto Inland Sea. The biomass of N.scintillans is not trivial as it occupies a substantial part of the plankton biomass, even when N.scintillans red tide has not occurred. We are studying about the variation in abundance of N.scintillans and its ecological role in the coastal water.

Publications

Tada, K., et al. (1998): Standing stocks and production rates of phytoplankton and abundance of bacteria in the Seto Inland  Sea, Japan.  Journal of Oceanography  54, 285 – 295.

Tada, K. et al. (2000): Carbon and nitrogen content of Noctiluca scintillans in the Seto Inland Sea, Japan.  Journal of   Plankton Research  22, 1203 – 1211.Tada, K., et al. (2004): Seasonal variation in the abundance of  Noctiluca scintillans in the Seto Inland Sea, Japan.  Plankton  Biology and Ecology,  51, 7-14.

Tada, K. et al. (2009) : Diatoms Grow Faster Using Ammonium in Rapidly Flushed Eutrophic Dokai Bay, Japan.. Journal of Oceanography, 65, 885 – 891.Nishikawa, T. et al. (2010) : Nutrient and Phytoplankton Dynamics in Harima-Nada, Eastern Seto Inland Sea, Japan During a 35 Year Period from 1973 to 2007. Estuaries and Coast, 33, 417 – 427.

Asahi, T. et al. (2014): Horizontal distribution of particulate matter and its characterization using phosphorous as an indicator in surface coastal water, Harima-Nada, the Seto Inland Sea, Japan, Journal of Oceanography, 70, 277 – 287.

多田ら (2014):瀬戸内海東部海域の栄養塩異変とその影響, 沿岸海洋研究,52,39-47.

Tada, K.,et al. (2017).: Negligible effect of the benthic fauna on measuring the nutrient  upward fluxes from coastal           sediments, Journal of Oceanography, 73, 397-402 .

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