Expelled zooxanthellae from corals; possible source as symbionts to other corals

2014 Fiscal Year Final Research Report

• Project/Area Number: 24570028
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Ecology/Environment
• Research Institution: Hiroshima University
• Principal Investigator: KOIKE Kazuhiko 広島大学, 生物圏科学研究科, 准教授 (30265722)
• Co-Investigator(Kenkyū-buntansha): YAMASHITA Hiroshi 独立行政法人水産総合研究センター, 西海区水産研究所, 研究員 (00583147)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: サンゴ / さんご礁 / 褐虫藻 / サンゴの白化 / ゾーザンテラ

Outline of Final Research Achievements

Expulsion of a symbiotic alga (zooxanthella) from several species of scleractinian corals was observed under different regimes of temperature stress. The corals expelled zooxanthellae even without giving temperature stress, and in this case, a half of the expelled population was consisted by the ones primarily subjected with coral digestion. Under the moderate heat stress, the ratio of such digested form increased and also the one with normal form but photosynthetically incompetent. These expulsion phenomena could be interpreted as the corals’ intrinsic mechanism to remove damaged zooxanthellae immediately. Under the non-stress condition, corals even expelled healthy zooxanthellae, which can be a source of symbiont for other corals.

Free Research Field

生物海洋学