How do you stop marine organisms from colonizing a tanker? Creative answers are needed to solve this problem, such as from the field of chemistry. What does a tanker care if barnacles colonize it? Well, given the gigantic dimensions of such ships, you would think: nothing at all.
After some time, you can see under the microscope how many organisms have stuck to the surface. This allows possible coatings to be compared. This idea is not new, of course. Algae, bacteria, mussels and barnacles have accompanied ships since time immemorial. The active ingredient tributyltin was particularly popular: a broad-spectrum biocide that, when released slowly, killed off anything that tried to colonize the surface of the ship.
However, it then turned out that the active ingredient acts like a hormone and accumulates in fish, thus entering the food chain. But the introduction of strict regulations in many ports means that the use of such coatings is on the decline. The aim is not so much to stop living organisms from attaching themselves to the ship in the first place, but to weaken their grip. In that case, they will simply be rinsed off by the flow of water as the ship travels.
The candidates include various bacteria and diatoms, for example. Both form biofilms and hide inside. Algae, barnacles and mussels are the largest species that make their home on ship hulls. Each species arrives separately and attaches itself in its own unique way. Many bacteria and algae secrete a gel-like matrix that first dries out the substrate and then sticks to it. Chemist Axel Rosenhahn is fascinated by the strategies that evolution has developed to make things stick under water.
In their larval stage, larger sea creatures such as barnacles move around in search of a place where they can settle. Their metamorphosis only begins once they have attached themselves. They walk on two legs, so-called antennae, which are covered with tiny hairs, similar to those of a gecko.
