About This Project

Urgent action is needed to protect coral reefs in the face of a changing climate. In Hawaiʻi, outflow from an electric plant warms a coral reef by 5 °C above normal. Surprisingly, corals are thriving here. If these corals have adapted to a warmer environment, they could enhance the long-term effectiveness of reef restoration efforts. In this project, we will conduct transplant experiments to test whether these corals retain their heat tolerance even after transplantation to cooler reefs.

Ask the Scientists

What is the context of this research?

As climate change pushes corals to the brink of their thermal tolerance, scientists and managers are turning to coral outplanting; however, this approach does not necessarily offer a solution because the corals placed on reefs may not be any more tolerant to rising temperatures than the dead counterparts that they are replacing. In western Oahu, corals live near outflow pipes of the Kahe Point electric plant, where water temperatures are elevated up to 5 °C above ambient. These corals offer a potentially powerful tool in “climate-proofing” Hawaiian reefs via restoration methods, but the efficacy of transplanting these corals has yet to be tested. Transplanting climate-proof corals is expected to have a direct restoring effect on the local reefs into which they are transplanted.

What is the significance of this project?

The reciprocal transplant experiment will reveal whether corals living at Kahe Point have developed heat tolerance that may enable them to persist as water temperatures continue to rise throughout this century, in addition to testing the ability of other corals to rapidly acclimate to higher temperatures. Thus, this project will identify if corals from Kahe Point are “climate-proof” and a good candidate for restoration efforts. Additionally, testing rates of acclimation will demonstrate the urgency with which management actions are required to combat the effects of climate change on Hawaiian reefs. The results of this study will therefore be directly applicable to organizations and agencies currently planning or practicing reef restoration efforts.

What are the goals of the project?

We will test whether corals living near or within the heated outflow of the Kahe Point pipes have developed heat tolerance that makes them resistant to bleaching. In other words, if these corals are transplanted to cooler environments, do they perform poorly or do they maintain their current fitness while retaining their heat tolerance? We will evaluate this using standardized photographs to document pigment changes that can reflect stress responses such as "bleaching", and by measuring coral growth rates via weight measurements at the beginning and end of the experiment. Answering this question is essential to understanding if these corals can be transplanted to improve the resilience of Hawaiian reefs to future bleaching events