日本地球惑星科学連合2019年大会

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[J] ポスター発表

セッション記号 A (大気水圏科学) » A-CG 大気海洋・環境科学複合領域・一般

[A-CG44] 沿岸海洋生態系─2.サンゴ礁・藻場・マングローブ

2019年5月28日(火) 10:45 〜 12:15 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:梅澤 有(東京農工大学)、宮島 利宏(東京大学 大気海洋研究所 海洋地球システム研究系 生元素動態分野)、渡邉 敦(笹川平和財団 海洋政策研究所)、樋口 富彦(東京大学大気海洋研究所)

[ACG44-P05] Enhancement of antioxidant activity of scleractinian coral Galaxea Fascicularis by feeding treatment.

*藤村 弘行1比嘉 彩也香1宮島 利宏2樋口 富彦2Sylvain Agostini3湯山 育子3中村 隆志4 (1.琉球大学、2.東京大学、3.筑波大学、4.東京工業大学)

キーワード:造礁サンゴ、従属栄養、抗酸化能

In recent years, mass coral bleaching has been recognized around the world. Coral bleaching is a phenomenon that coral loses symbiotic algae “zooxanthellae” due to strong solar radiation and high water temperature, and white coral skeleton can be seen through the transparent its soft tissue. Coral bleaching is caused by a damage of photosynthetic system of zooxanthella by strong light and the damaged part is not repaired by the continuation of the high water temperature, leading to a generation of harmful reactive oxygen species by combining surplus electrons and surrounding oxygen.
Since a translocation of fixed carbon from zooxanthellae to coral decreases during bleaching event, corals are forced to consume the stored lipids in the tissues. Prolonged bleaching event eventually causes the death of coral. Corals that store enough energy by predation have more resistance against bleaching (Ferrier-Pages et al. 2010). An addition of a trace amount of inorganic metals to corals has shown an increase in antioxidant enzyme activity (Sasaki 2013). Feeding activity is not only energy supply for coral but also supply of trace metal elements that can be used for the active center of antioxidant enzyme as a cofactor. It is possible that heterotrophic feeding may improve a tolerance of coral bleaching. Therefore, the aim of this study is to investigate experimentally whether antioxidant capacity can be enhanced by heterotrophic nutrition.
Coral polyps of Galaxea fascicularis were incubated with and without a feeding condition for 20 days. Zooplankton was given to coral at the dawn when coral actively extends its tentacles and takes predatory behavior (AM 5: 00 - 8: 00). After 20 days, the water temperature was raised up to 31ºC within 3 days. Finally, all the coral polyps were sacrificed and separated into host tissues and zooxanthella. Superoxide dismutase (SOD) enzyme activity of the antioxidant and concentration of the metal element contained in the protein were measured, respectively.
As a result of feeding experiment, the SOD enzyme activity increased under feeding conditions of 27 ℃ and maintained the activity level after exposure to high water temperature, indicating the enhancement of the antioxidant activity of G. fascicularis by feeding process.