Ocean acidification (OA) is a reduction in the pH of the ocean over time, caused primarily by uptake of carbon dioxide (CO2) from the earth’s atmosphere. OA reduces the amount of the calcium carbonate available, which marine organisms need to build their shells or skeletons. Marine organisms such as corals, clams, crabs and other shellfish may be threatened as OA continues to increase due to high concentrations of CO2. Therefore, our livelihood, economy, and culture will eventually be affected by OA as we are dependent on our ocean and the marine life.
New research by Palau International Coral Reef Center (PICRC) and the University of the Ryukyus shows potential for adaption to OA by corals in Nikko (Ngermid) Bay. This research titled “Potential local adaptation of corals at acidified and warmed Nikko Bay, Palau” was recently published in the science journal Scientific Reports.
The study was led by Dr. Haruko Kurihara from the University of the Ryukyus and include other researchers from University of the Ryukyus, PICRC, Tokyo Institute of Technology, The Sasakawa Peace Foundation, and Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC). These researchers found that the seawater environment in Nikko Bay was warmer (1-2 ℃ higher) and more acidic (0.3-0.4 lower pH) compared to outside of the bay. These environmental conditions are similar to what is expected to occur in the ocean by the end of this century due to the climate change, and these conditions are expected to be detrimental for most coral species. However, highly diverse and healthy coral communities were found within the bay.
Examining calcification, photosynthesis and respiration rates of corals in the bay and outside the bay, the authors of the study suggest that corals have the potential to acclimate and adapt to those warm and acidic conditions. Evaluating the mechanisms underlying these processes will help us in understanding how organisms have adapted and evolved under the changing environment that occurred in the past. Additionally, those data may give hints for potential conservation strategies for corals under future climate change.
This research was supported by Science and Technology Research Partnership for Sustainable Development (SATREPS). Supported by two Japanese government agencies, the Japan Science and Technology Agency (JST), and the Japan International Cooperation Agency (JICA), SATREPS is a Japanese government program that promotes international joint research targeting global issues.