Tonight we launched the OpenROV equipped with the payload to detect fluorescence in the ocean. It consists of a blue LED strip (excitation source), a power source and a GoPro with a yellow filter (detection). It was launched from the North of Aitutaki in the Cook Islands where an abundance of life exists, including corals, fish, clams etc. Given that many corals are known to fluoresce, our aim for the first trial was to detect fluorescence emitted from a coral. After only 9 minutes in the water fluorescence was detected! A fantastic green hue was observed coming into the view of the camera ending with the coral being seen to fluoresce at about 60-70cm. We believe the coral in the photo is a member of the Porites genus, though this is difficult to tell. Whilst the fluorescence is dimmer than using a torch, this proves the principle that we can detect fluorescence from an affordable ROV (OpenROV) which people from all over the world can have relatively easy access to. We hope that this method can be used to assess coral health and discover a novel fluorescent protein and proving it works is a massive step forward in this research. Perhaps this is the beginning of a great way for everyone to join in and start to systematically assess coral health.

Furthermore a vivid pink colour was observed (picture not shown) using a blue diving torch and a yellow filter and whilst this can be seen in normal conditions, it is particularly vivid with the torch. This was later identified to be a disease that affects Porites coral. So we should definitely quantify the pink areas as well as the total fluorescence as a proxy for coral health.

A few adjustments need to be made to optimise the performance of the ROV, including tinkering with the weight distribution, ballast and buoyancy of the payload. Given the torch has shown better results at the same distances, we may also try and attach it to the ROV and compare the data. Furthermore we ran into a few problems with the tether getting caught on corals, as such we’re going to use a positively buoyant tether on the next tests to avoid this happening again.