2017 Fiscal Year Research-status Report
Potential of coral resilience in an acidifying ocean
Project/Area Number |
17K17621
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Research Institution | University of Tsukuba |
Principal Investigator |
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Project Period (FY) |
2017-04-01 – 2020-03-31
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Keywords | coral / ocean acidification / CO2 seep / ETSA |
Outline of Annual Research Achievements |
During the year FY2017, the main focus was to assess the link between energy production in corals and its implication for OA resilience. This was tested on coral that were assessed as resilient and non resilient by conducting field surveys at two CO2 seeps in Shikine Island and Papua New Guinea. Acroporids were generally found to be less resilient than massive or encrusting corals (such as Poritids). The energy production potential was assessed by measuring mitochondrial electron transport system activity (ETSA). Resilient corals were found to have a statistically significant higher ETSA normalized to biomass (protein content). The effect of transplantation from reference pCO2 to high pCO2 zones was also tested. The ETSA activities, did not significantly change after transplantation. Overall these results suggest that coral resilience to OA may be a innate tolerance provided by a higher ETSA. To test the second hypothesis on the link of coral morphologies and OA resilience, a custom made flume aquarium, that is suitable to measure pH and dissolved oxygen in the diffusive boundary layer of different corals species (different morphologies) under various flow rates (laminar flow) was built and tested. Moreover, to confirm the general resilience of corals massive vs branching corals, a long term transplantation under elevated CO2 of these two types of morphologies was started at the CO2 seep in Shikine Island. Finally, a long term experiment in the laboratory is being run to test the effect of multiple levels of CO2.
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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
Because the opportunity to go to Papua New Guinea to conduct field survey at the CO2 seeps arised, a higher priority was put on resolving the link between energy production and ocean acidification rather than the morphology effects. Thus CO2 seeps offers a unique opportunity for such study as corals are exposed to life long elevated CO2. On the other hand, the link between morphologies and tolerances to OA, is more suitably tested in the laboratory.
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Strategy for Future Research Activity |
The second year of the research will be to test the link between coral morphologies and ocean resilience. Different species with different morphologies were sampled during FY2017 and are now stored in aquarium with running seawater at the Shimoda Marine Research Center to acclimate them to aquarium conditions. The required flume aquarium was built and preliminary tests run to check whether laminar flow can be achieved under different flow rates including those observed under natural conditions. The FY2018 will therefore be dedicated to run the experiments in the laboratory. In addition, a system for the transplantation of corals with controlled flow rates in the field is being worked on and is expected to be ready during FY2018.
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Causes of Carryover |
Due to the move of focus towards the link of energy and coral resilience to OA in the FY2017, the budget during the FY2018 will be mainly allocated to the study of the link between morphologies and coral resilience to OA using microsensors techniques. Therefore microsensors probes, pH (unisense, 150,000JPY per probe, 3 months lifetime) and dissolved oxygen probes (unisense, 200,000JPY per probe, 6 months lifetime) will be purchased in addition to a specific software for the measurement using microsensors (unisense TraceSuite, 400,000JPY). Field and laboratory measurement of energy production will still be conducted and therefore consummables for running cost are accounted for a total of 500,000JPY. To be able to conduct field surveys and transplantation at the Shikine CO2 seep, 150,000JPY are planned and finally presentation of the results obtained during FY2017 and FY2018 is planned at the Japanese Coral Reef Symposium to be held in Okinawa and the symposium Ocean in a high CO2 world, and therefore travel expenses is planned to an amount of 400,000JPY
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