2020 Fiscal Year Research-status Report
Identifying "super corals" in Mauritius: what physiological factors promote high recovery after bleaching?
| Project/Area Number |
18KK0298
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| Research Institution | Shizuoka University |
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Principal Investigator |
CASARETO Beatriz 静岡大学, 創造科学技術大学院, 特任教授 (60402244)
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| Co-Investigator(Kenkyū-buntansha) |
藤原 健智 静岡大学, 創造科学技術大学院, 教授 (80209121)
天野 豊己 静岡大学, 理学部, 准教授 (90297945)
RAMPHUL CHITRA 静岡大学, 創造科学技術大学院, 研究員 (20832661)
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| Project Period (FY) |
2018-10-09 – 2022-03-31
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| Keywords | Mauritius / Super Coral / coral bleaching / oxidative stress / thermal tolerant / genome analysis / Symbiodiniaceae / physiological factor |
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| Outline of Annual Research Achievements |
This study aims to describe the physiological mechanisms that promote a successful response of thermally tolerant corals, which we define as
“super corals". We surveyed two target reefs: Albion (A) (shallow, human impacted) and Belle-Mare (BM) (deep, less affected). We sampled 17 and 19 coral colonies in A and BM respectively. Results from these studies showed that rather than in A, corals in BM were highly exposed to stressful condition judging from the high allomer/Chl-a indicating oxidative stress condition of symbionts and the total holobiont affected judging from the high gly/glu ratio in the tissues of corals from BM. Nevertheless these corals were successful in keeping high Fv/Fm with healthy zooxanthellae (even under bleached condition) with high Chl-a/cell. High % of the bacterium Endozoicomonas in Pocillopora corals at BM confirmed their healthy condition. The presence of Symbiodiniaceae of Clade D (Genus Durusdinium) (thermal resistant) reinforced “super coral” features. In terms of coral species, Pocillopora eydouxi, Pavona sp and Montipora sp were the species classified as "super corals". We had tested the selected "super corals" in incubations under stressful temperatures (2 and 4 degrees over normal)with a successful recovery keeping their intact their photosynthetic performance. We successfully published two scientific papers in international journals in collaboration with Mauritius researchers, including the participation of 3 early career researchers from both sides.
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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
Due to the covid-19 we were not able to trip to Mauritius planed in March of 2021, however we had developed a number of activities in cooperation with the University of Mauritius: We developed 4 times on-line seminars for young researchers with about 20 participants each time. Other on-line meetings were held for data analysis and planning. We had performed detailed physiological studies to identify those parameters defining “super corals”. On these bases, we had identified “super corals” species and performed incubations under stressful conditions of high temperature to evaluate their response. Data are actually under analysis. We had also accomplished training and education of young scientists. We success in getting the UNESCO/K. Obuchi Young Researcher Fellowship to give training to a Mauritius PhD candidate at Shizuoka University from August to October 2021. We had prepared a joint report to fulfill the requirements for an RCA between Univ. of Mauritius and Shizuoka Univ. that also covers the requested report for coral sampling permits. We had published three joint paper in collaboration with Mauritius scientists (Journal of Sustainability Science and Management, Marine Pollution Bulletin and Research Journal of Microbiology) and we have two more manuscript under review. We had also submitted two joint abstract to the 14th International Coral Reef Symposium (ICRS) to be held in Bremen, Germany from 18-28 July 2021
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| Strategy for Future Research Activity |
At the moment The Republic of Mauritius is under locked down due to spreading of Covid-19, therefore we were not able to trip in this fiscal year. We are expecting to be able to trip to Mauritius during this fiscal year once the quarantine is over. We plan to (a) Continuing surveys in the two selected reefs. (b) Evaluation of coral physiological responses using incubation under normal vs. stressful conditions of temperature and light with (3-4 days), and posterior recovery (4-6 days). Coral nubbins under normal (ambient) and stressful temperatures (plus 2 to 4 °C) and light (over 1500 micromol cm-2 sec-1) will be incubated to evaluate their responses in the reduction of oxidative stress and apoptosis, defense against infections, feeding under normal or bleached conditions. We will test posterior recovery capacity, by placing the corals back to ambient conditions. Experiments will be done at the University of Mauritius (UoM) laboratory facilities. (c) We will hold the second workshop at UoM. Finally we will create a summary with conclusions and recommendations:
(a) Create a first molecular genetic catalogue/database for Symbiodinium from corals of Mauritius. (b) Summary of data with characterization of
a “super coral” and identification of such areas in Mauritius that can provide “super corals” for the future of African Reefs (c) Make
relevant recommendations for inclusion of areas bearing “super corals” in Marine Protected Areas
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| Causes of Carryover |
Due to the spreading of corona-virus infection we could not trip to the Republic of Mauritius during the 2020 fiscal year, therefore we requested an extension to finalize the remaining surveys and experiments in Mauritius during the present fiscal year.
Actually the Republic of Mauritius is under a situation of lockdown due to the spreading of covid-19. We are expecting to be able to trip to Mauritius once the lockdown in the country is resumed.
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