Abstract


A 100 YEARS CORAL GROWTH HISTORY IN VOLCANICALLY ACIDIFIED ENVIRONMENTS: ANALOGUES FOR CORAL ACCLIMATION TO FUTURE OCEAN ACIDIFICATION

Experimental and modelling studies are suggesting that the projected ocean acidification due to rising atmospheric carbon dioxide concentrations would have dramatically influenced on the calcification processes of marine organisms. Recent field based observation in volcanically acidified coral reefs have revealed on-going drastic ecological shifts. However, the long-term observation is very limited for the prediction of coral acclimation in future acidified ocean predicted in next century. Tropical shallow water corals could record long-term growth histories in annual bands of their aragonite skeletons as well as marine environmental changes during a few hundreds years. We discovered the large massive Porites corals living around active volcanic island of Satsuma Io-Jima, Japan, providing a unique opportunity to observe marine organism living under extreme environments of low pH condition accompanied with volcanic gases emission from sea flower. We collected coral cores around the island inside and outside the rim ridges of Kikai caldera. We applied geochemical approaches (δ18O, δ13C, Sr/Ca, Mg/Ca, Ba/Ca, and F/Ca) and x-ray densitometry (calcification rate, skeletal density, and extension rate) to demonstrate the relationship between volcanic and hydrothermal activities and coral growth characteristics during last one hundred years, including submarine volcanic eruption in 1934. Coral extension rate at the site near hydrothermal vent was significantly small, suggesting the influence by low pH water and/or hydrothermal activity. We discuss the possible future analogue of coral acclimation against ocean acidification and marine pollution in natural system.

Authors

Watanabe, T., Hokkaido University, Japan, nabe@mail.sci.hokudai.ac.jp

KAMIMURA, K., Hokkaido University, Japan, k.kanae@frontier.hokudai.ac.jp

SEKIYA, S., Hokkaido University, Japan, sekiya@mail.sci.hokudai.ac.jp

Yamazaki, A., Hokkaido University, Japan, zaki@mail.sci.hokudai.ac.jp

Omori, K., Hokkaido University, Japan, kazuto.omori@gmail.com

LE GUERN, F., CNRS, France

KIYOKAWA, S., Kyushu University, Japan, kiyokawa@geo.kyushu-u.ac.jp

Details

Oral presentation

Session #:32
Date: 06/23/2016
Time: 13:45
Location: 314

Presentation is given by student: No