Barnacles may have a small footprint, but their effect on global shipping is large.

When ships’ hulls get coated with barnacles and other creatures, they use more fuel and eventually must be hauled out of water and scraped clean, at an estimated cost of several billion dollars a year. Fuel burned by the shipping industry is a significant contributor to global carbon emissions, too.

To keep barnacles off hulls, boats are coated in antifouling paint that kills barnacle larvae. Unfortunately, the paints’ active ingredients also leach into the water and kill other things, like oysters, leading to bans on some formulations and a search for alternatives.

Researchers who study the physics of sticky biological structures at Kiel University in Germany reported last week in the Journal of the Royal Society Interface that one option may involve texture, rather than chemicals. Covering surfaces with microscopic structures shaped like mushrooms, they find, keeps barnacles from getting a firm foothold.