2018 Fiscal Year Research-status Report
Creating marine forests that can withstand herbivory
| Project/Area Number |
17KT0149
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| Research Institution | Nagasaki University |
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Principal Investigator |
ニシハラ グレゴリーナオキ 長崎大学, 海洋未来イノベーション機構, 准教授 (40508321)
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| Co-Investigator(Kenkyū-buntansha) |
戸田 龍樹 創価大学, 理工学部, 教授 (10222150)
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| Project Period (FY) |
2017-07-18 – 2020-03-31
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| Keywords | いそやけ / 付着藻類 / 栄養塩 / ウニ |
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| Outline of Annual Research Achievements |
In Mushima Island, Ojika-machi, Nagasaki Prefecture, two study sites were selected in 2017 October. In 2018 September, 6 permanent stations were setup, two in site A and 4 in site B. At site A, one station was fertilized with inorganic P and the other was not fertilized. Both remained unprotected from herbivores. At site B, the stations were stup as 2x2 matrix of inorganic P fertilization and herbivore protection. Concrete blocks with Sargassum embryos were placed at each site. The survival rate of these embryos were monitored monthly at each site. By 2018 December, there was no evidence of any embryos surviving at each site. The reason for the poor survival rates are not clear, but we believe that water temperature is the cause, since the water temperature did not drop below 14 degrees C during the winter and were as high as 28 degrees C during the summer. Sargassum embryos have better survival rates in cooler waters.
At the same time, interactions between seaweed and sea urchins are being examined at our field station. It is clear that when dead sea urchins are present, grazing activity of live sea urchins are reduced. This suggests that sea urchins change their behavior during stress, which can reduce grazing.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The results for the seaweed -- sea urchin interaction is very clear. There is a real reduction in grazing by live sea urchins when the sea urchins are present.
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| Strategy for Future Research Activity |
We will continue to examine the influence of nutrients on seaweed growth, but we may change our experimental procedure and do this in controlled tanks. We are conducting experiments to examine if there is any seasonality in the way sea urchins react to dead sea urchins and how this affects herbivory. We expect to be able to publish these results by the end of FY2019.
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| Causes of Carryover |
We were able to save costs on batteries and travel. Therefore, we will use these saved funds to repair equipment that was damaged during 2017 and 2018.
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