Navy Lab Continues Fight Against Age-Old Foe.

• Author: Mayfield, Mandy
• Position: NEWS BRIEFS

* The Naval Research Laboratory is not giving up the battle against one of the sea service's toughest and longest-standing foes: barnacles.

For mariners, barnacles are an ancient scourge. Even today, they cost the Navy billions of dollars and continue to pose a sticky problem for scientists.

Barnacles, mussels and algae are primary sources of biofouling, and are looking for a place to settle down. They will try to adhere to anything, including the bottom of a ship.

The Navy wants to make barnacles feel unwelcome, said Kathryn Wahl, a chemist and materials scientist from the Naval Research Laboratory and a coatings and biofouling program officer with the Office of Naval Research.

Barnacles are especially problematic because they slow a ship down and increase fuel consumption. Even the newest ship or most recently cleaned hull will be subject to biofouling from the moment it enters the water. Unless protected by an antifouling coating, in just two weeks their presence is enough to cause drag and they start becoming hard to remove.

In just six months, a guided missile destroyer's speed will be reduced by two knots unless the bottom is cleaned, and this effect increases in warmer water. It requires time and resources to scrape them off and takes ships offline and away from their operational duties. That's why the Navy wants to get the upper hand against these underwater pests. Better to keep them off the ship in the first place.

"Their success is largely due to an ability to adhere to diverse substrates by secreting a thin adhesive layer that is deposited as the organism grows and expands its base," Wahl said of the barnacles.

Barnacles, like mussels and tubeworms, secrete extremely strong glues that cure underwater. Mussels can make more than 20 types of proteins in the glue; and scientists have found and begun to identify more than 50 proteins in the barnacle adhesive interface.

The lab's researchers are examining the chemistry of the glue, how it's made and how it gets applied to a surface.

They are also studying how the shape and design of the shell, which functions as armor for the barnacle, contributes to the difficulty of removing them from surfaces.

"We are working to better understand how barnacles adhere to surfaces, and through that inform new ways to produce alternatives to toxic paints and surface treatments. Some of our research materials are showing promise in this area," said...