Scotland may not be the first place that comes to mind when you think of coral reefs, but the deep waters west of the nation are indeed home to reefs not unlike those found in the tropics. Unfortunately, a commercial fishing technique known as bottom trawling regularly damages that coral, putting the reefs at risk. Now, scientists are working on a possible solution to the problem – swarms of small, autonomous coral-fixing robots.

Bottom trawling involves the use of nets that are weighted along their bottom edge, so that it sinks right down to the sea floor. As the surface-located trawler then pulls the net through the water, the weights drag along the bottom, crashing into whatever is in their path. When they encounter coral reefs, they smash branches of coral off of them.

The sort-of good news is that if those branches are found reasonably quickly and cemented back onto the reef, they will resume growing. Presently, such work is conducted mostly by volunteer scuba divers. Unfortunately, however, these divers are limited both in the amount of time they can stay underwater, and the depths to which they can go ... that’s why a group of scientists from Scotland’s Heriot Watt University are developing underwater robots to do the job.

The so-called “coralbots” would function like swarming insects such as bees or wasps, that work together in large groups to build structures. In the case of the coralbots, they would operate according to simple pre-programmed rules. These would allow them to cooperate with one another in first differentiating broken-off coral fragments from other seabed debris such as rocks or litter, and then retrieving those fragments and cementing them back onto the reef.

While a smaller number of larger remote-operated vehicles (ROVs) could presumably be used for such work, there are advantages to the swarm approach. Most importantly, because any of one of the robots isn’t as crucial a part of the project, they don’t need to be built as robust or sophisticated. Should one of them be damaged – which is quite likely to happen, over 200 meters (656 feet) beneath the North Atlantic – the other coralbots could simply adapt to take on their workload.

While the research is still in its early stages, there are big hopes for its applications, not just in Scotland but in oceans all over the world. “Swarms of robots could be instantaneously deployed after a hurricane or in a deep area known to be impacted by trawling, and rebuild the reef in days to weeks, instead of years to centuries,” said project leader Dr. Lea-Anne Henry.