HYPER3D

Artificial reefs are now considered to be a valuable tool to restore destructed reef habitats. 3D printers allow artificial reefs to be built with a high three-dimensional complexity, which mimic the complexity of natural habitats. A successful restoration then supposes that the progressive colonization of the artificial reef has a food web organization and ecosystem functions close to those observed in natural habitats. Therefore, once installed, artificial reefs need to be monitored to make sure that the colonization operates in a natural way. In this project, we are developing and testing an innovative tool: a hyperspectral camera to monitor the very first stages of colonization and food web development (macrofouling). Each underwater species is indeed characterized by a unique set of multi-spectral colors that the human eye cannot accurately perceive, whereas a hyperspectral camera can record the entire spectrum from the visible to the invisible.

We acquired an underwater hyperspectral camera that was being developed by a start-up, Plan Blue (https://www.planblue.com/). We tested it in 2018 in the Larvotto marine protected area (Monaco), conducting the first hyperspectral camera analysis in the Mediterranean Sea. The preliminary results revealed the large spectral diversity in the protected area, which we interpret as a valuable proxy for its species richness. The individual species identification was more difficult however, calling for further improvement of the camera to succeed discriminating the individual signals. We are therefore in the process of guiding the improvement of the camera to make it more sensitive to individual species. Meanwhile, total spectral diversity can now be used as a valuable proxy to monitor the growing colonization of artificial reefs.