Takayoshi Kato

Investigation for Modeling of Sessile Organisms on Coastal Floating Structures

Through the investigation about environmental impacts of Mega-Float, it is revealed that the effect of sessile organisms adhering on the floating structure is significant. However there had been little information about activities of the sessile organisms on floating structures and their influences on water and bottom quality. Therefore, some experiments were carried out to investigate the uncertain processes caused by the sessile organisms. An instrument called “Bell-jar”, which is composed of an enclosed container and several sensors for measuring water quality in it, was developed to measure the activities of sessile organisms on artificial bases set in Tokyo Bay. Through the experiments using Bell-jar, the consumption rate of dissolved oxygen and Chlorophyll-a, and emission rate of nutrients by the sessile organisms were measured. By fitting the model to these results, the parameters for activities of sessile organisms such as respiration rate and filtering rate were determined. The experiments have been carried out under various conditions of water temperature and salinity and it is clarified that the activities of sessile organisms very much depend on the water temperature and salinity. The behavior of particulate organic matters excreted from the sessile organisms is also investigated by laboratory experiments. These results were used to improving the model of sessile organisms, which is incorporated into the numerical ecosystem model for environmental impact assessment of very large floating structures.Copyright

A Fundamental Study on the Effect of Ocean Fertilization by Deep Sea Water

본 연구에서 식물플랑크톤 뿐 아니라 동물플랑크톤을 포함하는 생태계 모델을 이용하여 해양 심층수의 해역 비옥화의 효과를 검증하였다. 모델은 2종의 식물플랑크톤, 3종의 동물플랑크톤, 질산염, 암모늄염, 규산염, 입자성 유기질소, 용존 유기질소, 입자성 규소 총 11개 요소로 구성된 NEMURO에 기초하고 있다. NEMURO의 11개 요소 외에도 두 종의 식물플랑크톤내 질소 셀 쿼터와 대형 식물플랑크톤내 규산염 셀 쿼터를 추가하였다. 해역 비옥화 효과를 조사하기 위해서 이즈 오시마 섬에서 실험을 실시하였지만, 본 실험에서 심층수의 유무에 의한 명확한 차이를 확인할 수 없었다. 이 실험 결과의 원인들을 모델 시뮬레이션에 의해 조사하였으며, 그 원인의 하나는 실험에 사용된 표층수의 높은 영양염 농도이다. 다른 원인은 무기질소 섭취율이

Visualization of the ambient wave field and the elastic responses of a very large floating structure in waves by use of a very small water tank

NH_4

A comparative study of the biomass-based and individual-based models of blue mussels

에 대한

Changes in the coastal environment in Kamaishi Bay after the Great East Japan Earthquake

NO_3

Assessment of environmental variations caused by a very large floating structure in a semi-closed bay

의 비율에 관련되어 있으므로 무기질소의 총 농도의 증가가 광합성 속도를 반드시 증진시키지 않는다는 것이다. 이 모델로 실험 결과들을 재현할 수 있었기 때문에 우리는 이 모델을 이용하여 해양 심층수에 의한 해역 비옥화의 효과를 검증하였다. 해양 심층수의 공급 간격이 너무 짧거나 해양 심층수의 양이 너무 많을 때 해역 비옥화 효과는 나타나기 어려운 것으로 밝혀졌다. 해양 심층수의 첨가가 너무 비번하거나 너무 많이 첨가하면 플랑크톤 농도의 희석이 식물플랑크톤의 광합성 증진 효과를 초과해 버린 것으로 추측된다. 【In this study, we investigated the effect of ocean fertilization by deep sea water, using an ecosystem model which contains not only phytoplankton but also zooplankton. The model is based on NEMURO which consists of eleven compartments - two species of phytoplankton, three species of zooplankton,

Measurement of Oceanophysical Environment around Mega-Float Model Moored in Tokyo Bay

NO_3

A fundamental study on behavior of deep ocean water discharged for seaweed bed generation

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Behaviour analysis of deep ocean water discharged in a small port

NH_4

A study on the shielding effects among wind-turbines in a floating wind farm (2nd Report)

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