U.S. Navy Researchers Unlock Secrets Behind Barnacle Glue

The U.S. Naval Research Laboratory has achieved an important milestone towards understanding one of the most persistent species of marine biofouling: the barnacle. 

Barnacles may not seem complex, but scientists have never been able to fully characterize the tough glue that sticks these small organisms to the hull of a ship. Some of the proteins in barnacle glue can be dissolved in solvents and analyzed, but some cannot - at least until this point. Scientists at the U.S. Naval Research Laboratory have now found a way to dissolve all of the glue and process multiple samples at the same time, allowing them to characterize twice as many glue proteins as in previous studies. 

Postdoc Janna Schultzhaus and her fellow researchers at NRL recently designed a study to test how well their barocycler machine, a laboratory instrument used to subject specimens to cycles of high pressure, could break down the proteins with three test solvents. The method proved successsful, and Schultzhaus' team used it to identify more than 80 proteins, about double the number identified in previous studies. They also discovered several enzymes, which Schultzhaus believes may play a role in the production of glue, the transport of proteins or the support of the barnacle molting process. 

"We now have a controlled way to break the glue down and see what’s there and what’s changing,” Schultzhaus said. “If we can figure out how to make them not attach as well, they will be easier to remove or [ensure] they just won’t attach. That would save the Navy a lot of money.” 

Barnacles are an important focus for antifouling research because they impart significant drag and are notoriously difficult to remove. One specifically-targeted anti-barnacle compound has already reached the marketplace - the coating additive Selektope, which is designed to activate barnacle larvae's swim response and cause them to leave the hull surface before adhering.