Such coatings could completely replace more toxic copper-based coatings
While the sight of barnacles on ships’ hulls may seem like a very normal part of the maritime environment, the fact is that the presence of such organisms makes a vessel much less streamlined. The harder it is for a ship to slice through the water, the harder its engines have to work and the more fuel it uses. Although there are some anti-fouling coatings that can be applied to hulls, these are often toxic, and can leach into the surrounding water and harm marine organisms. Some recent efforts at eco-friendly solutions have included using fungus and seed-inspired coatings, but scientists at Sweden’s University of Gothenburg are now reporting success with the use of molecules created by a certain type of bacteria.
The molecules are known as macrocyclic lactones, and barnacles don’t like them. In field tests, trace amounts of the lactones were added to a regular anti-fouling coating, which was then applied to a boat’s hull – a binding agent kept the molecules from dispersing into the water. Although the barnacle larvae then colonized the hull as per usual, when they matured into adults and tried to establish a more secure hold, they lost their footing and were swept away.
Apparently, a marine species of brown algae uses the molecules in the same way, to keep barnacles from accumulating on its leaves.