Beneath The Sea

Coral reefs and marine life are under threat. Acidification of the oceans worldwide due to rising sea temperatures and water pollution is leading to the destructive phenomenon of coral bleaching. This disrupts the symbiotic relationship between coral and algae causing the reef to die, leaving countless sea creatures without a habitat. As well as providing protection and food for marine life, coral reefs are a vital source of oxygen and form indispensable natural barriers that help shield coastal regions from tsunamis and hurricanes.

Providing damaged reefs with new physical structures to house corals can aid significantly with the rehabilitation process. The first phase of investigating how to produce these structures sustainably then was to focus on an environmentally-friendly material, clay, and evaluate its behavior during different additive manufacturing methods, such as 3D printing. The research group of Gramazio & Kohler, a pioneer of digital fabrication in architecture, played an important role in this. They were ready to share their know-how, and the ZHdK, another cooperation partner in this project, provided their premises and 3D clay printer for producing different prototypes. A major challenge was to find suitable ways to gather knowledge from different disciplines and then integrate it into the entire prototype manufacturing process.

In the next phase, it was necessary to investigate how the different prototypes behave under water. Together with the marine biologist Dr. Ulrike Pfreundt, samples with different roughness and amplitudes were produced. The first prototypes were tested by simulating a current. Using the PIV technique (Particle Image Velocimetry), researchers from ETH Environmental Fluid Dynamics (EFM) were able to analyze which structures reduce the current and help the coral larvae to settle. Their results helped to finalise the design of the full-scale model.

Practical testing of the resulting prototypes started in December 2019. They were released into the water in the Maldives in order to find out, which surface structure would work best. Just one month later it was observed that the first larvae had settled. Some of these prototypes were integrated into the Material Archive of the ZHdK and the ETH Material Hub as reference objects and can be viewed there.

Project Duration

1. March 2019 – 31. March 2020

After the Project

The project is continued in the form of the organisation rrreefs. It was co-founded in summer 2020 by Marie Griesmar and Ulrike Pfreundt, a marine biologist and ETH Zurich alumna. Both are now jointly pursuing their goal to support the restoration of coral reefs around the world.