Cool Reef : A temperature-controlled environment for coral development

The main objective of “COOLREEF” is to create a temperature-controlled environment for coral development and compare a cooled area to an uncooled control area. The research was located on Tetiaroa Atoll, around the facilities of “The Brando” hotel, using the hotel’s existing Sea Water Air Conditioning infrastructure (SWAC)

In December 2022, the project team installed coral tables near the SWAC outflow pipes at a depth of approximately 12 meters, setting up cooled and control nurseries. Different coral species, known for their sensitivity to bleaching, were selected for the study, including Acropora globiceps and Pocillopora verrucosa. The cooling intervention was planned for the hot months of February to May 2024, coinciding with potential bleaching events.

COOLREEF has laid the foundation for further studies, suggesting modifications to the SWAC configuration to improve cooling efficiency and uniformity across the reef area. The project aligns with global efforts such as RRAP in Australia, demonstrating potential adaptation strategies for coral conservation in the face of increasing sea temperatures.

Early results from the project indicate a marked improvement in the thermal environment of the cooled nursery, with temperatures maintained 1-2°C lower than the control site. This should mitigate the effects of bleaching and promote coral health. However, a full analysis of coral health, growth rates and environmental parameters such as pH and salinity is pending, with data to be assessed after the project.

Fragments of Acropora globiceps in April, during bleaching, under normal conditions, shade, and cooling