Low-cost tool for the 3D virtual reconstruction of cold-water corals in aquaria

Why is the use of the 3D virtual reconstruction cold-water coral tool important?

Studies have showed stressors driven from global change (global warming, deoxygenation, and ocean acidification) are likely to affect the ecophysiological processes and performance (i.e., skeletal growth, respiration, or excretion rates) of cold-water corals. The 3D virtual reconstructions with this new tool will help us better understand and evaluate the effects of climate change on the ecophysiology of the corals in laboratory conditions.

Is the 3D virtual reconstruction cold-water coral tool useful?

Absolutely! It allows for the continuous monitoring of the apparent health of cold-water corals maintained in aquaria: It can be used to monitor tissue regeneration or retraction, changes in the structure of the tissue or the proportion of exposed skeleton, and allows the measurement of the growth.

It provides a very accurate quantification of the surface of the nubbin and can be useful for normalising ecophysiological data by tissue surface, as it is done with weight. In most cases, leading to a reduction of their manipulation, and in some cases avoiding sacrificing specimens to obtain the same or similar data. It also allows for the quantification of other variables such as polyp number from cold-water corals that have complex shapes (e.g. heavily branched octocorals and antipatharians). The accuracy of the tool has been repeatedly proven – the team has already captured more than 3600 photos that have led to 120 successful 3D coral virtual reconstructions, proving the reliability of the system.

What is the novelty of the tool?

The novelty is that the coral is automatically turned by a microprocessor that remains out of the water without drilling the aquarium. Therefore, the camera does not have to move around and there is no risk of water damage on the system. The microprocessor also calculates the number of angles that the coral has to turn based on the selected photos per turn and automatically activates the camera shutter. You can also customise the waiting time before and after every shot, depending on the camera settings and the complexity of the coral. Moreover, it is a very cost-effective tool with guaranteed long-term performance. The software that you will need (e.g. Agisoft Metashape, MeshLab) is either open-access or available through relatively cheap student licences that can be used by multiple users. Hence, the total cost for building and using this tool will not exceed €3,000.