Education Spotlight

Biofouling is the formation of a film of bacteria or larger marine organisms such as barnacles after the surface of an object has been immersed in water.

BREVARD COUNTY • MELBOURNE, FLORIDA – A group of Florida Tech researchers is working to understand how water pressure in the deep ocean affects biofilms and larger biofouling organisms by refurbishing a practical tool: a deep-sea pressure chamber.

Biofouling is the growth of a film of bacteria or larger marine life such as barnacles after the surface of an object has been submerged in water. It can affect the functionality of a ship by slowing it down, causing the ship to burn more fuel and emit more greenhouse gases.

All commercially available antifouling paints and coatings are designed for use on surface vessels. The U.S. Navy is interested in how hydrostatic pressure affects these materials and whether repeated pressure cycles negatively affect their ability to prevent or inhibit biofouling.

The chamber was originally built by Edwin Link, the visionary inventor of the flight simulator, an ally of Florida Tech’s founding president Jerome Keuper, and co-founder of the Harbor Branch Oceanographic Institution. Link, whose name adorns Florida Tech’s building that houses ocean engineering and marine sciences, donated the chamber to Florida Tech.

The chamber can simulate the pressure at a depth of up to 300 meters below the sea surface. However, due to a defective pump, the chamber could not reach this depth.

Thanks to recent funding from the Naval Undersea Warfare Center, Assistant Professor Kelli Hunsucker and graduate student Geligne Franklin are using the pressure chamber to conduct deep-sea biofouling research. Although the chamber is functional, part of their funding will go toward refurbishing it to make it fully operational.

This was accomplished by Florida Tech’s machine shop and design center.

Their research examines how biofilms colonize surfaces and how these biofilms are affected by changes in hydrostatic pressure (e.g. when a submarine or unmanned underwater vehicle descends). They hope to use the chamber to find out whether higher pressure kills biofilm-forming organisms.

“Do we even need to worry about the biofilm that builds up on a submarine? That was kind of the main reason for it,” Hunsucker said. “If you have a biofilm that grew in shallow water when the ship was docked and then exposed to different pressures, is that biofilm going to die off?”

Hunsucker’s previous research looked at this growth on ship hulls and ways to control it.

Starting with the pressure chamber, researchers will determine whether growth at greater depths is even a problem. If the growth is killed by the pressure, the next question is how long it needs to remain at that level to die, Hunsucker said.

However, if the biofilm still exists after the pressure is applied, other questions arise.

“If (the surface) comes back and that biofilm is still there, the biofilm can get thicker or be a precursor to the next layer of pollution, like barnacles and weeds and other things that will grow on top of it,” Hunsucker said.

As for improvements to the chamber, Hunsucker’s team added several new components, including a new pump and a new cart. With the pump in working order, they will finally attempt to increase the pressure in the chamber to 450 PSI (about 1,050 feet deep).

“(We’re) really trying to push some of these biofilms to the max,” Hunsucker said.

The first phase of testing involved growing a biofilm on surfaces in the house and then pressurizing the surfaces in the chamber to see how they are affected. The second phase will take place in the Bahamas to compare the chamber’s results to pressure in a real marine environment.

“I’m really excited to see how (the results) fit together,” Franklin said.

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