1089 / 2024-09-20 11:37:06

Physiological and Biogeochemical Responses of Super-Corals to extreme cold Stress from Dongshan sea at the Northernmost edge of South China Sea

Cold stress, resilience, energy reserves, hetertrophy, coral physiology

Session 59 - Impacts of Climate and Biogeochemical Extremes on Marine Organisms and Ecosystems

Dongshan’s Seawater are affected by both the coastal currents of Zhejiang, Fujian and eastern Guangdong, as well as the warm current of Taiwan and the South China Sea, with an average monthly salinity of 31.3-32.9 and water temperature of 14-28 °C. The data shows that the waters of Higashiyama have been many low temperature leaves. For example, in mid-January 2011, the water temperature was below 13°C, lasted for 3 weeks and the lowest recorded temperature was 11.8°C, and the Dongshan Bay buoy recorded a low temperature of 13^oC. It's not known what kind of pressure these cryogenic events exert on the coral ecosystem and how corals will adapt to this extreme cold stress. Therefore, it is urgent to clarify the mechanism by which reef-building corals can cope with extreme low temperatures and/or recover after cold bleaching. In the present abstract we will compare between the physiological performance of feed and starved corals under extreme cold stress which may be a key factor solving resistance of some corals to extreme cold stress and/or recover after cold bleaching, as well as the dynamic structure of symbiont community associated within corals under extreme cold stress. In order to investigate how the heterotrophic feeding of the coral modifies the carbon budget and thus improving the physiological process of the two partners of the symbiosis under extreme cold stress after testing the two hypotheses that we imposed for this study. We hypothesis that the heterotrophic feeding will maintain symbiont concentration and photosynthesis during cold stress and thereby maintain the carbon acquisition and translocation compared to stressed and starved corals. We also hypothesis that dissolved organic carbon and particulate organic matter uptake will mitigate the loss of autotrophic carbon during cold bleaching events in Dongshan corals, and also it will meet carbon required for daily metabolic energy during bleaching and absence of their symbiotic algae that would support quickly coral recovery after extreme cold stress.